Vol. 78 Thursday, 

No. 177 September 12, 2013 

Part II 

Department of Labor 

Occupational Safety and Health Administration 

29 CFR Parts 1910, 1915, and 1926 

Occupational Exposure to Respirable Crystalline Silica; Proposed Rule 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56274 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

DEPARTMENT OF LABOR 

Occupational Safety and Health 

Administration 

29 CFR Parts 1910, 1915, and 1926 

[Docket No. OSHA–2010–0034] 

RIN 1218–AB70 

Occupational Exposure to Respirable 

Crystalline Silica 

AGENCY: Occupational Safety and Health 

Administration (OSHA), Department of 

Labor. 

ACTION: Proposed rule; request for 

comments. 

SUMMARY: The Occupational Safety and 

Health Administration (OSHA) proposes 

to amend its existing standards for 

occupational exposure to respirable 

crystalline silica. The basis for issuance 

of this proposal is a preliminary 

determination by the Assistant Secretary 

of Labor for Occupational Safety and 

Health that employees exposed to 

respirable crystalline silica face a 

significant risk to their health at the 

current permissible exposure limits and 

that promulgating these proposed 

standards will substantially reduce that 

risk. 

This document proposes a new 

permissible exposure limit, calculated 

as an 8-hour time-weighted average, of 

50 micrograms of respirable crystalline 

silica per cubic meter of air (50 mg/m3). 

OSHA also proposes other ancillary 

provisions for employee protection such 

as preferred methods for controlling 

exposure, respiratory protection, 

medical surveillance, hazard 

communication, and recordkeeping. 

OSHA is proposing two separate 

regulatory texts—one for general 

industry and maritime, and the other for 

construction—in order to tailor 

requirements to the circumstances 

found in these sectors. 

DATES: Written comments. Written 

comments, including comments on the 

information collection determination 

described in Section IX of the preamble 

(OMB Review under the Paperwork 

Reduction Act of 1995), must be 

submitted (postmarked, sent, or 

received) by December 11, 2013. 

Informal public hearings. The Agency 

plans to hold informal public hearings 

beginning on March 4, 2014, in 

Washington, DC. OSHA expects the 

hearings to last from 9:30 a.m. to 5:30 

p.m., local time; a schedule will be 

released prior to the start of the 

hearings. The exact daily schedule may 

be amended at the discretion of the 

presiding administrative law judge 

(ALJ). If necessary, the hearings will 

continue at the same time on 

subsequent days. Peer reviewers of 

OSHA’s Health Effects Literature 

Review and Preliminary Quantitative 

Risk Assessment will be present in 

Washington, DC to hear testimony on 

the second day of the hearing, March 5, 

2014; see Section XV for more 

information on the peer review process. 

Notice of intention to appear at the 

hearings. Interested persons who intend 

to present testimony or question 

witnesses at the hearings must submit 

(transmit, send, postmark, deliver) a 

notice of their intention to do so by 

November 12, 2013. The notice of intent 

must indicate if the submitter requests 

to present testimony in the presence of 

the peer reviewers. 

Hearing testimony and documentary 

evidence. Interested persons who 

request more than 10 minutes to present 

testimony, or who intend to submit 

documentary evidence, at the hearings 

must submit (transmit, send, postmark, 

deliver) the full text of their testimony 

and all documentary evidence by 

December 11, 2013. See Section XV 

below for details on the format and how 

to file a notice of intention to appear, 

submit documentary evidence at the 

hearing, and request an appropriate 

amount of time to present testimony. 

ADDRESSES: Written comments. You may 

submit comments, identified by Docket 

No. OSHA–2010–0034, by any of the 

following methods: 

Electronically: You may submit 

comments and attachments 

electronically at http://

www.regulations.gov, which is the 

Federal e-Rulemaking Portal. Follow the 

instructions on-line for making 

electronic submissions. 

Fax: If your submissions, including 

attachments, are not longer than 10 

pages, you may fax them to the OSHA 

Docket Office at (202) 693–1648. 

Mail, hand delivery, express mail, 

messenger, or courier service: You must 

submit your comments to the OSHA 

Docket Office, Docket No. OSHA–2010– 

0034, U.S. Department of Labor, Room 

N–2625, 200 Constitution Avenue NW., 

Washington, DC 20210, telephone (202) 

693–2350 (OSHA’s TTY number is (877) 

889–5627). Deliveries (hand, express 

mail, messenger, or courier service) are 

accepted during the Department of 

Labor’s and Docket Office’s normal 

business hours, 8:15 a.m.–4:45 p.m., 

E.T. 

Instructions: All submissions must 

include the Agency name and the 

docket number for this rulemaking 

(Docket No. OSHA–2010–0034). All 

comments, including any personal 

information you provide, are placed in 

the public docket without change and 

may be made available online at http:// 

www.regulations.gov. Therefore, OSHA 

cautions you about submitting personal 

information such as social security 

numbers and birthdates. 

If you submit scientific or technical 

studies or other results of scientific 

research, OSHA requests (but is not 

requiring) that you also provide the 

following information where it is 

available: (1) Identification of the 

funding source(s) and sponsoring 

organization(s) of the research; (2) the 

extent to which the research findings 

were reviewed by a potentially affected 

party prior to publication or submission 

to the docket, and identification of any 

such parties; and (3) the nature of any 

financial relationships (e.g., consulting 

agreements, expert witness support, or 

research funding) between investigators 

who conducted the research and any 

organization(s) or entities having an 

interest in the rulemaking. If you are 

submitting comments or testimony on 

the Agency’s scientific and technical 

analyses, OSHA requests that you 

disclose: (1) The nature of any financial 

relationships you may have with any 

organization(s) or entities having an 

interest in the rulemaking; and (2) the 

extent to which your comments or 

testimony were reviewed by an 

interested party prior to its submission. 

Disclosure of such information is 

intended to promote transparency and 

scientific integrity of data and technical 

information submitted to the record. 

This request is consistent with 

Executive Order 13563, issued on 

January 18, 2011, which instructs 

agencies to ensure the objectivity of any 

scientific and technological information 

used to support their regulatory actions. 

OSHA emphasizes that all material 

submitted to the rulemaking record will 

be considered by the Agency to develop 

the final rule and supporting analyses. 

Informal public hearings. The 

Washington, DC hearing will be held in 

the auditorium of the U.S. Department 

of Labor, 200 Constitution Avenue NW., 

Washington, DC 20210. 

Notice of intention to appear, hearing 

testimony and documentary evidence. 

You may submit (transmit, send, 

postmark, deliver) your notice of 

intention to appear, hearing testimony, 

and documentary evidence, identified 

by docket number (OSHA–2010–0034), 

by any of the following methods: 

Electronically: http://

www.regulations.gov. Follow the 

instructions online for electronic 

submission of materials, including 

attachments. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56275 

Fax: If your written submission does 

not exceed 10 pages, including 

attachments, you may fax it to the 

OSHA Docket Office at (202) 693–1648. 

Regular mail, express delivery, hand 

delivery, and messenger and courier 

service: Submit your materials to the 

OSHA Docket Office, Docket No. 

OSHA–2010–0034, U.S. Department of 

Labor, Room N–2625, 200 Constitution 

Avenue NW., Washington, DC 20210; 

telephone (202) 693–2350 (TTY number 

(877) 889–5627). Deliveries (express 

mail, hand delivery, and messenger and 

courier service) are accepted during the 

Department of Labor’s and OSHA 

Docket Office’s normal hours of 

operation, 8:15 a.m. to 4:45 p.m., ET. 

Instructions: All submissions must 

include the Agency name and docket 

number for this rulemaking (Docket No. 

OSHA–2010–0034). All submissions, 

including any personal information, are 

placed in the public docket without 

change and may be available online at 

http://www.regulations.gov. Therefore, 

OSHA cautions you about submitting 

certain personal information, such as 

social security numbers and birthdates. 

Because of security-related procedures, 

the use of regular mail may cause a 

significant delay in the receipt of your 

submissions. For information about 

security-related procedures for 

submitting materials by express 

delivery, hand delivery, messenger, or 

courier service, please contact the 

OSHA Docket Office. For additional 

information on submitting notices of 

intention to appear, hearing testimony 

or documentary evidence, see Section 

XV of this preamble, Public 

Participation. 

Docket: To read or download 

comments, notices of intention to 

appear, and materials submitted in 

response to this Federal Register notice, 

go to Docket No. OSHA–2010–0034 at 

http://www.regulations.gov or to the 

OSHA Docket Office at the address 

above. All comments and submissions 

are listed in the http://

www.regulations.gov index; however, 

some information (e.g., copyrighted 

material) is not publicly available to 

read or download through that Web site. 

All comments and submissions are 

available for inspection and, where 

permissible, copying at the OSHA 

Docket Office. 

Electronic copies of this Federal 

Register document are available at 

http://regulations.gov. Copies also are 

available from the OSHA Office of 

Publications, Room N–3101, U.S. 

Department of Labor, 200 Constitution 

Avenue NW., Washington, DC 20210; 

telephone (202) 693–1888. This 

document, as well as news releases and 

other relevant information, is also 

available at OSHA’s Web site at http:// 

www.osha.gov. 

FOR FURTHER INFORMATION CONTACT: For 

general information and press inquiries, 

contact Frank Meilinger, Director, Office 

of Communications, Room N–3647, 

OSHA, U.S. Department of Labor, 200 

Constitution Avenue NW., Washington, 

DC 20210; telephone (202) 693–1999. 

For technical inquiries, contact William 

Perry or David O’Connor, Directorate of 

Standards and Guidance, Room N–3718, 

OSHA, U.S. Department of Labor, 200 

Constitution Avenue NW., Washington, 

DC 20210; telephone (202) 693–1950 or 

fax (202) 693–1678. For hearing 

inquiries, contact Frank Meilinger, 

Director, Office of Communications, 

Room N–3647, OSHA, U.S. Department 

of Labor, 200 Constitution Avenue NW., 

Washington, DC 20210; telephone (202) 

693–1999; email meilinger.francis2@

dol.gov. 

SUPPLEMENTARY INFORMATION: 

The preamble to the proposed 

standard on occupational exposure to 

respirable crystalline silica follows this 

outline: 

I. Issues 

II. Pertinent Legal Authority 

III. Events Leading to the Proposed Standards 

IV. Chemical Properties and Industrial Uses 

V. Health Effects Summary 

VI. Summary of the Preliminary Quantitative 

Risk Assessment 

VII. Significance of Risk 

VIII. Summary of the Preliminary Economic 

Analysis and Initial Regulatory 

Flexibility Analysis 

IX. OMB Review Under the Paperwork 

Reduction Act of 1995 

X. Federalism 

XI. State Plans 

XII. Unfunded Mandates 

XIII. Protecting Children From 

Environmental Health and Safety Risks 

XIV. Environmental Impacts 

XV. Public Participation 

XVI. Summary and Explanation of the 

Standards 

(a) Scope and Application 

(b) Definitions 

(c) Permissible Exposure Limit (PEL) 

(d) Exposure Assessment 

(e) Regulated Areas and Access Control 

(f) Methods of Compliance 

(g) Respiratory Protection 

(h) Medical Surveillance 

(i) Communication of Respirable 

Crystalline Silica Hazards to Employees 

(j) Recordkeeping 

(k) Dates 

XVII. References 

XVIII. Authority and Signature 

OSHA currently enforces permissible 

exposure limits (PELs) for respirable 

crystalline silica in general industry, 

construction, and shipyards. These PELs 

were adopted in 1971, shortly after the 

Agency was created, and have not been 

updated since then. The PEL for quartz 

(the most common form of crystalline 

silica) in general industry is a formula 

that is approximately equivalent to 100 

micrograms per cubic meter of air (mg/ 

m3) as an 8-hour time-weighted average. 

The PEL for quartz in construction and 

shipyards is a formula based on a nowobsolete particle count sampling 

method that is approximately equivalent 

to 250 mg/m3. The current PELs for two 

other forms of crystalline silica 

(cristobalite and tridymite) are one-half 

of the values for quartz in general 

industry. OSHA is proposing a new PEL 

for respirable crystalline silica (quartz, 

cristobalite, and tridymite) of 50 mg/m3

in all industry sectors covered by the 

rule. OSHA is also proposing other 

elements of a comprehensive health 

standard, including requirements for 

exposure assessment, preferred methods 

for controlling exposure, respiratory 

protection, medical surveillance, hazard 

communication, and recordkeeping. 

OSHA’s proposal is based on the 

requirements of the Occupational Safety 

and Health Act (OSH Act) and court 

interpretations of the Act. For health 

standards issued under section 6(b)(5) of 

the OSH Act, OSHA is required to 

promulgate a standard that reduces 

significant risk to the extent that it is 

technologically and economically 

feasible to do so. See Section II of this 

preamble, Pertinent Legal Authority, for 

a full discussion of OSHA legal 

requirements. 

OSHA has conducted an extensive 

review of the literature on adverse 

health effects associated with exposure 

to respirable crystalline silica. The 

Agency has also developed estimates of 

the risk of silica-related diseases 

assuming exposure over a working 

lifetime at the proposed PEL and action 

level, as well as at OSHA’s current 

PELs. These analyses are presented in a 

background document entitled 

‘‘Respirable Crystalline Silica—Health 

Effects Literature Review and 

Preliminary Quantitative Risk 

Assessment’’ and are summarized in 

this preamble in Section V, Health 

Effects Summary, and Section VI, 

Summary of OSHA’s Preliminary 

Quantitative Risk Assessment, 

respectively. The available evidence 

indicates that employees exposed to 

respirable crystalline silica well below 

the current PELs are at increased risk of 

lung cancer mortality and silicosis 

mortality and morbidity. Occupational 

exposures to respirable crystalline silica 

also may result in the development of 

kidney and autoimmune diseases and in 

death from other nonmalignant 

respiratory diseases, including chronic 

obstructive pulmonary disease (COPD). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56276 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

1Am. Textile Mfrs. Inst., Inc. v. Nat’l Cotton 

Council of Am., 452 U.S. 490, 513 (1981); Pub. 

Citizen Health Research Group v. U.S. Dep’t of 

Labor, 557 F.3d 165, 177 (3d Cir. 2009); Friends of 

the Boundary Waters Wilderness v. Robertson, 978 

F.2d 1484, 1487 (8th Cir. 1992). 

As discussed in Section VII, 

Significance of Risk, in this preamble, 

OSHA preliminarily finds that worker 

exposure to respirable crystalline silica 

constitutes a significant risk and that the 

proposed standard will substantially 

reduce this risk. 

Section 6(b) of the OSH Act requires 

OSHA to determine that its standards 

are technologically and economically 

feasible. OSHA’s examination of the 

technological and economic feasibility 

of the proposed rule is presented in the 

Preliminary Economic Analysis and 

Initial Regulatory Flexibility Analysis 

(PEA), and is summarized in Section 

VIII of this preamble. For general 

industry and maritime, OSHA has 

preliminarily concluded that the 

proposed PEL of 50 mg/m3 is 

technologically feasible for all affected 

industries. For construction, OSHA has 

preliminarily determined that the 

proposed PEL of 50 mg/m3 is feasible in 

10 out of 12 of the affected activities. 

Thus, OSHA preliminarily concludes 

that engineering and work practices will 

be sufficient to reduce and maintain 

silica exposures to the proposed PEL of 

50 mg/m3 or below in most operations 

most of the time in the affected 

industries. For those few operations 

within an industry or activity where the 

proposed PEL is not technologically 

feasible even when workers use 

recommended engineering and work 

practice controls, employers can 

supplement controls with respirators to 

achieve exposure levels at or below the 

proposed PEL. 

OSHA developed quantitative 

estimates of the compliance costs of the 

proposed rule for each of the affected 

industry sectors. The estimated 

compliance costs were compared with 

industry revenues and profits to provide 

a screening analysis of the economic 

feasibility of complying with the revised 

standard and an evaluation of the 

potential economic impacts. Industries 

with unusually high costs as a 

percentage of revenues or profits were 

further analyzed for possible economic 

feasibility issues. After performing these 

analyses, OSHA has preliminarily 

concluded that compliance with the 

requirements of the proposed rule 

would be economically feasible in every 

affected industry sector. 

OSHA directed Inforum—a not-forprofit corporation (based at the 

University of Maryland) well recognized 

for its macroeconomic modeling—to run 

its LIFT (Long-term Interindustry 

Forecasting Tool) model of the U.S. 

economy to estimate the industry and 

aggregate employment effects of the 

proposed silica rule. Inforum developed 

estimates of the employment impacts 

over the ten-year period from 2014– 

2023 by feeding OSHA’s year-by-year 

and industry-by-industry estimates of 

the compliance costs of the proposed 

rule into its LIFT model. Based on the 

resulting Inforum estimates of 

employment impacts, OSHA has 

preliminarily concluded that the 

proposed rule would have a negligible— 

albeit slightly positive—net impact on 

aggregate U.S. employment. 

OSHA believes that a new PEL, 

expressed as a gravimetric measurement 

of respirable crystalline silica, will 

improve compliance because the PEL is 

simple and relatively easy to 

understand. In comparison, the existing 

PELs require application of a formula to 

account for the crystalline silica content 

of the dust sampled and, in the case of 

the construction and shipyard PELs, a 

conversion from particle count to mg/

m3 as well. OSHA also expects that the 

approach to methods of compliance for 

construction operations included in this 

proposal will improve compliance with 

the standard. This approach, which 

specifies exposure control methods for 

selected construction operations, gives 

employers a simple option to identify 

the control measures that are 

appropriate for these operations. 

Alternately, employers could conduct 

exposure assessments to determine if 

worker exposures are in compliance 

with the PEL. In either case, the 

proposed rule would provide a basis for 

ensuring that appropriate measures are 

in place to limit worker exposures. 

The Regulatory Flexibility Act, as 

amended by the Small Business 

Regulatory Enforcement Fairness Act 

(SBREFA), requires that OSHA either 

certify that a rule would not have a 

significant economic impact on a 

substantial number of small firms or 

prepare a regulatory flexibility analysis 

and hold a Small Business Advocacy 

Review (SBAR) Panel prior to proposing 

the rule. OSHA has determined that a 

regulatory flexibility analysis is needed 

and has provided this analysis in 

Section VIII.G of this preamble. OSHA 

also previously held a SBAR Panel for 

this rule. The recommendations of the 

Panel and OSHA’s response to them are 

summarized in Section VIII.G of this 

preamble. 

Executive Orders 13563 and 12866 

direct agencies to assess all costs and 

benefits of available regulatory 

alternatives. Executive Order 13563 

emphasizes the importance of 

quantifying both costs and benefits, of 

reducing costs, of harmonizing rules, 

and of promoting flexibility. This rule 

has been designated an economically 

significant regulatory action under 

section 3(f)(1) of Executive Order 12866. 

Accordingly, the rule has been reviewed 

by the Office of Management and 

Budget, and the remainder of this 

section summarizes the key findings of 

the analysis with respect to costs and 

benefits of the rule and then presents 

several possible alternatives to the rule. 

Table SI–1—which, like all the tables 

in this section, is derived from material 

presented in Section VIII of this 

preamble—provides a summary of 

OSHA’s best estimate of the costs and 

benefits of the proposed rule using a 

discount rate of 3 percent. As shown, 

the proposed rule is estimated to 

prevent 688 fatalities and 1,585 silicarelated illnesses annually once it is fully 

effective, and the estimated cost of the 

rule is $637 million annually. Also as 

shown in Table SI–1, the discounted 

monetized benefits of the proposed rule 

are estimated to be $5.3 billion 

annually, and the proposed rule is 

estimated to generate net benefits of 

$4.6 billion annually. These estimates 

are for informational purposes only and 

have not been used by OSHA as the 

basis for its decision concerning the 

choice of a PEL or of other ancillary 

requirements for this proposed silica 

rule. The courts have ruled that OSHA 

may not use benefit-cost analysis or a 

criterion of maximizing net benefits as 

a basis for setting OSHA health 

standards.1

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56277 

Both the costs and benefits of Table 

SI–1 reflect the incremental costs and 

benefits associated with achieving full 

compliance with the proposed rule. 

They do not include (a) costs and 

benefits associated with current 

compliance that have already been 

achieved with regard to the new 

requirements, or (b) costs and benefits 

associated with achieving compliance 

with existing requirements, to the extent 

that some employers may currently not 

be fully complying with applicable 

regulatory requirements. They also do 

not include costs or benefits associated 

with relatively rare, extremely high 

exposures that can lead to acute 

silicosis. 

Subsequent to completion of the PEA, 

OSHA identified an industry, hydraulic 

fracturing, that would be impacted by 

the proposed standard. Hydraulic 

fracturing, sometimes called ‘‘fracking,’’ 

is a process used to extract natural gas 

and oil deposits from shale and other 

tight geologic formations. A recent 

cooperative study by the National 

Institute for Occupational Safety and 

Health (NIOSH) and industry partners 

identified overexposures to silica among 

workers conducting hydraulic fracturing 

operations. An industry focus group has 

been working with OSHA and NIOSH to 

disseminate information about this 

hazard, share best practices, and 

develop engineering controls to limit 

worker exposures to silica. OSHA finds 

that there are now sufficient data to 

provide the main elements of the 

economic analysis for this rapidly 

growing industry and has done so in 

Appendix A to the PEA. 

Based on recent data from the U.S. 

Census Bureau and industry sources, 

OSHA estimates that roughly 25,000 

workers in 444 establishments (operated 

by 200 business entities) in hydraulic 

fracturing would be affected by the 

proposed standard. Annual benefits of 

the proposed 50 mg/m3 PEL include 

approximately 12 avoided fatalities—2.9 

avoided lung cancers (mid-point 

estimate), 6.3 prevented non-cancer 

respiratory illnesses, and 2.3 prevented 

cases of renal failure—and 40.8 avoided 

cases of silicosis morbidity. Monetized 

benefits are expected to range from 

$75.1 million at a seven percent 

discount rate to $105.4 million at a three 

percent discount rate to undiscounted 

benefits of $140.3 million. OSHA 

estimates that under the proposed 

standard, annualized compliance costs 

for the hydraulic fracturing industry 

will total $28.6 million at a discount 

rate of 7 percent or $26.4 million at a 

discount rate of 3 percent. 

In addition to the proposed rule itself, 

this preamble discusses several 

regulatory alternatives to the proposed 

OSHA silica standard. These are 

presented below as well as in Section 

VIII of this preamble. OSHA believes 

that this presentation of regulatory 

alternatives serves two important 

functions. The first is to explore the 

possibility of less costly ways (than the 

proposed rule) to provide an adequate 

level of worker protection from 

exposure to respirable crystalline silica. 

The second is tied to the Agency’s 

statutory requirement, which underlies 

the proposed rule, to reduce significant 

risk to the extent feasible. If, based on 

evidence presented during notice and 

comment, OSHA is unable to justify its 

preliminary findings of significant risk 

and feasibility as presented in this 

preamble to the proposed rule, the 

Agency must then consider regulatory 

alternatives that do satisfy its statutory 

obligations. 


mstockstill on DSK4VPTVN1PROD with PROPOSALS2EP12SE13.000</GPH>
56278 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

Each regulatory alternative presented 

here is described and analyzed relative 

to the proposed rule. Where 

appropriate, the Agency notes whether 

the regulatory alternative, to be a 

legitimate candidate for OSHA 

consideration, requires evidence 

contrary to the Agency’s findings of 

significant risk and feasibility. To 

facilitate comment, the regulatory 

alternatives have been organized into 

four categories: (1) Alternative PELs to 

the proposed PEL of 50 mg/m3; (2) 

regulatory alternatives that affect 

proposed ancillary provisions; (3) a 

regulatory alternative that would modify 

the proposed methods of compliance; 

and (4) regulatory alternatives 

concerning when different provisions of 

the proposed rule would take effect. 

In addition, OSHA would like to draw 

attention to one possible modification to 

the proposed rule, involving methods of 

compliance, that the Agency would not 

consider to be a legitimate regulatory 

alternative: To permit the use of 

respiratory protection as an alternative 

to engineering and work practice 

controls as a primary means to achieve 

the PEL. 

As described in Section XVI of the 

preamble, Summary and Explanation of 

the Proposed Standards, OSHA is 

proposing to require primary reliance on 

engineering controls and work practices 

because reliance on these methods is 

consistent with long-established good 

industrial hygiene practice, with the 

Agency’s experience in ensuring that 

workers have a healthy workplace, and 

with the Agency’s traditional adherence 

to a hierarchy of preferred controls. The 

Agency’s adherence to the hierarchy of 

controls has been successfully upheld 

by the courts (see AFL–CIO v. Marshall, 

617 F.2d 636 (D.C. Cir. 1979) (cotton 

dust standard); United Steelworkers v. 

Marshall, 647 F.2d 1189 (D.C. Cir. 

1980), cert. denied, 453 U.S. 913 (1981) 

(lead standard); ASARCO v. OSHA, 746 

F.2d 483 (9th Cir. 1984) (arsenic 

standard); Am. Iron & Steel v. OSHA, 

182 F.3d 1261 (11th Cir. 1999) 

(respiratory protection standard); Pub. 

Citizen v. U.S. Dep’t of Labor, 557 F.3d 

165 (3rd Cir. 2009) (hexavalent 

chromium standard)). 

Engineering controls are reliable, 

provide consistent levels of protection 

to a large number of workers, can be 

monitored, allow for predictable 

performance levels, and can efficiently 

remove a toxic substance from the 

workplace. Once removed, the toxic 

substance no longer poses a threat to 

employees. The effectiveness of 

engineering controls does not generally 

depend on human behavior to the same 

extent as personal protective equipment 

does, and the operation of equipment is 

not as vulnerable to human error as is 

personal protective equipment. 

Respirators are another important 

means of protecting workers. However, 

to be effective, respirators must be 

individually selected; fitted and 

periodically refitted; conscientiously 

and properly worn; regularly 

maintained; and replaced as necessary. 

In many workplaces, these conditions 

for effective respirator use are difficult 

to achieve. The absence of any of these 

conditions can reduce or eliminate the 

protection that respirators provide to 

some or all of the employees who wear 

them. 

In addition, use of respirators in the 

workplace presents other safety and 

health concerns. Respirators impose 

substantial physiological burdens on 

some employees. Certain medical 

conditions can compromise an 

employee’s ability to tolerate the 

physiological burdens imposed by 

respirator use, thereby placing the 

employee wearing the respirator at an 

increased risk of illness, injury, and 

even death. Psychological conditions, 

such as claustrophobia, can also impair 

the effective use of respirators by 

employees. These concerns about the 

burdens placed on workers by the use 

of respirators are the basis for the 

requirement that employers provide a 

medical evaluation to determine the 

employee’s ability to wear a respirator 

before the employee is fit tested or 

required to use a respirator in the 

workplace. Although experience in 

industry shows that most healthy 

workers do not have physiological 

problems wearing properly chosen and 

fitted respirators, common health 

problems can sometime preclude an 

employee from wearing a respirator. 

Safety problems created by respirators 

that limit vision and communication 

must also be considered. In some 

difficult or dangerous jobs, effective 

vision or communication is vital. Voice 

transmission through a respirator can be 

difficult and fatiguing. 

Because respirators are less reliable 

than engineering and work practice 

controls and may create additional 

problems, OSHA believes that primary 

reliance on respirators to protect 

workers is generally inappropriate when 

feasible engineering and work practice 

controls are available. All OSHA 

substance-specific health standards 

have recognized and required employers 

to observe the hierarchy of controls, 

favoring engineering and work practice 

controls over respirators. OSHA’s PELs, 

including the current PELs for 

respirable crystalline silica, also 

incorporate this hierarchy of controls. In 

addition, the industry consensus 

standards for crystalline silica (ASTM E 

1132–06, Standard Practice for Health 

Requirements Relating to Occupational 

Exposure to Respirable Crystalline 

Silica, and ASTM E 2626–09, Standard 

Practice for Controlling Occupational 

Exposure to Respirable Crystalline 

Silica for Construction and Demolition 

Activities) incorporate the hierarchy of 

controls. 

It is important to note that the very 

concept of technological feasibility for 

OSHA standards is grounded in the 

hierarchy of controls. As indicated in 

Section II of this preamble, Pertinent 

Legal Authority, the courts have 

clarified that a standard is 

technologically feasible if OSHA proves 

a reasonable possibility, 

. . . within the limits of the best available 

evidence . . . that the typical firm will be 

able to develop and install engineering and 

work practice controls that can meet the PEL 

in most of its operations. [See United 

Steelworkers v. Marshall, 647 F.2d 1189, 

1272 (D.C. Cir. 1980)] 

Allowing use of respirators instead of 

engineering and work practice controls 

would be at odds with this framework 

for evaluating the technological 

feasibility of a PEL. 

Alternative PELs 

OSHA has examined two regulatory 

alternatives (named Regulatory 

Alternatives #1 and #2) that would 

modify the PEL for the proposed rule. 

Under Regulatory Alternative #1, the 

proposed PEL would be changed from 

50 mg/m3 to 100 mg/m3 for all industry 

sectors covered by the rule, and the 

action level would be changed from 25 

mg/m3 to 50 mg/m3 (thereby keeping the 

action level at one-half of the PEL). 

Under Regulatory Alternative #2, the 

proposed PEL would be lowered from 

50 mg/m3 to 25 mg/m3 for all industry 

sectors covered by the rule, while the 

action level would remain at 25 mg/m3

(because of difficulties in accurately 

measuring exposure levels below 25 mg/ 

m3). 

Tables SI–2 and SI–3 present, for 

informational purposes, the estimated 

costs, benefits, and net benefits of the 

proposed rule under the proposed PEL 

of 50 mg/m3 and for the regulatory 

alternatives of a PEL of 100 mg/m3 and 

a PEL of 25 mg/m3 (Regulatory 

Alternatives #1 and #2), using 

alternative discount rates of 3 and 7 

percent. These two tables also present 

the incremental costs, the incremental 

benefits, and the incremental net 

benefits of going from a PEL of 100 mg/ 

m3 to the proposed PEL of 50 mg/m3 and 

then of going from the proposed PEL of 

50 mg/m3 to a PEL of 25 mg/m3. Table 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2


EP12SE13.001</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table 51·2: Annualized Costs, Benefits and Incremental Benefits of OSHA's Proposed Silica Standard of 50 (.191m3 and 100 (.191m3 Alternative 

Millions ($2009) 

25b!9/m3 Incremental Costs/Benefits 50l;!g/m3 Incremental Costs/Benefits 

Discount Rate --EL 3% 

Annualized Costs 

Engineering Controls (includes Abrasive Blasting) $330 $344 $0 $0 $330 $344 $187 $197 

Respirators $421 $422 $330 $331 $91 $91 $88 $88 Exposure Assessment $203 $203 $131 $129 $73 $74 $26 $26 Medical Surveillance $219 $227 $143 $148 $76 $79 $28 $29 

Training $49 $50 $0 $0 $49 $50 $0 $0 

Regulated Area or Access Control $65 $86 $66 $66 $19 

Total Annualized Costs (point estimate) $1,308 $1,332 $670 $674 $637 $658 $339 $351 

Annual Benefits: Number of Cases Prevented Cases Cases Cases Cases Cases 

Fatal Lung Cancers (midpoint estimate) 257 75 162 79 83 Fatal Silicosis & other 527 152 375 186 189 Respiratory Diseases Fatal Renal Disease 258 108 151 91 60 

Mortality 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,116 331 

Silicosis Morbidity 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $544 953 

Monetized Annual Benefits (midpoint estimate) $7,030 $4,684 $1,776 $1,188 $5,254 $3,495 $2,495 $1,659 Net Benefits $5722 $3352 $1105 $514 $4617 $2838 $2157 $1308 

Source: U.S, Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory AnalysIs 
As Tables SI–2 and SI–3 show, going 

from a PEL of 100 mg/m3 to a PEL of 50 

mg/m3 would prevent, annually, an 

additional 357 silica-related fatalities 

the proposed PEL of 50 

Based on its preliminary findings that 

and an additional 632 cases of silicosis. 

mg/m3

significantly reduces worker risk from technologically and economically 

silicosis cases avoided) and is both 

number of silica-related fatalities and 

silica exposure (as demonstrated by the 


EP12SE13.002</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table SI-3: Annualized Costs, Benefits and Incremental Benefits of OSHA's Proposed Silica Standard of 50 j.lg/m3 and 100 jJg/m3 Alternative, by Major 

Millions ($2009) 

251!g/m3 Incremental Costs/Benefits 50 l!9!m3 Incremental Costs/B

Discount Rate 

Annualized Costs 

Construction $1,043 $1,062 $548 $551 $495 $511 $233 $2

General Industry/Maritime $264 $270 $122 $123 $143 $147 $106 $1

Total Annualized Costs $1,308 $1,332 $670 $674 $637 $658 $339 $3

Annual Benefits: Number of Cases 

Prevented Cases Cases Cases Cases 

Silica-Related Mortality 

Construction 802 $3,804 $2,504 235 $1,109 $746 567 $2,695 $1,758 242 $1,158 $76

General Industry/Maritime 221 $1,007 $657 100 $434 $283 121 $573 $374 115 $545 $35

Total 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,1

Silicosis Morbidity 

Construction 1,157 $1,451 $996 77 $96 $66 1,080 $1,354 $930 161 $202 $13

General Industry/Maritime 613 $768 $528 109 $136 $94 504 $632 $434 471 $590 $40

Total 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $54

Monetized Annual Benefits (midpoint 

estimate) 

Construction $5,255 $3,500 $1,205 $812 $4,049 $2,688 $1,360 $89

General Industry/Maritime $1,775 $1,164 $570 $377 $1,205 $808 $1,135 $76

Total $7,030 $4,684 $1,776 $1,188 $5,254 $3,495 $2,495 $1,6

Net Benefits 

Construction $4,211 $2,437 $657 $261 $3,555 $2,177 $1,127 $65

General Industry/Maritime $1,511 $914 $448 $254 $1,062 $661 $1,029 $65

Total $5,722 $3,352 $1,105 $514 $4,617 $2,838 $2,157 $1,3

Source: U,S, Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and AnalYSiS, Office of Regulatory Analysis 
Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56281 

feasible, OSHA cannot propose a PEL of 

100 mg/m3 (Regulatory Alternative #1) 

without violating its statutory 

obligations under the OSH Act. 

However, the Agency will consider 

evidence that challenges its preliminary 

findings. 

As previously noted, Tables SI–2 and 

SI–3 also show the costs and benefits of 

a PEL of 25 mg/m3 (Regulatory 

Alternative #2), as well as the 

incremental costs and benefits of going 

from the proposed PEL of 50 mg/m3 to 

a PEL of 25 mg/m3. Because OSHA 

preliminarily determined that a PEL of 

25 mg/m3 would not be feasible (that is, 

engineering and work practices would 

not be sufficient to reduce and maintain 

silica exposures to a PEL of 25 mg/m3 or 

below in most operations most of the 

time in the affected industries), the 

Agency did not attempt to identify 

engineering controls or their costs for 

affected industries to meet this PEL. 

Instead, for purposes of estimating the 

costs of going from a PEL of 50 mg/m3

to a PEL of 25 mg/m3, OSHA assumed 

that all workers exposed between 50 mg/ 

m3 and 25 mg/m3 would have to wear 

respirators to achieve compliance with 

the 25 mg/m3 PEL. OSHA then estimated 

the associated additional costs for 

respirators, exposure assessments, 

medical surveillance, and regulated 

areas (the latter three for ancillary 

requirements specified in the proposed 

rule). 

As shown in Tables SI–2 and SI–3, 

going from a PEL of 50 mg/m3 to a PEL 

of 25 mg/m3 would prevent, annually, an 

additional 335 silica-related fatalities 

and an additional 186 cases of silicosis. 

These estimates support OSHA’s 

preliminarily finding that there is 

significant risk remaining at the 

proposed PEL of 50 mg/m3. However, the 

Agency has preliminarily determined 

that a PEL of 25 mg/m3 (Regulatory 

Alternative #2) is not technologically 

feasible, and for that reason, cannot 

propose it without violating its statutory 

obligations under the OSH Act. 

Regulatory Alternatives That Affect 

Ancillary Provisions 

The proposed rule contains several 

ancillary provisions (provisions other 

than the PEL), including requirements 

for exposure assessment, medical 

surveillance, training, and regulated 

areas or access control. As shown in 

Table SI–2, these ancillary provisions 

represent approximately $223 million 

(or about 34 percent) of the total 

annualized costs of the rule of $658 

million (using a 7 percent discount 

rate). The two most expensive of the 

ancillary provisions are the 

requirements for medical surveillance, 

with annualized costs of $79 million, 

and the requirements for exposure 

monitoring, with annualized costs of 

$74 million. 

As proposed, the requirements for 

exposure assessment are triggered by the 

action level. As described in this 

preamble, OSHA has defined the action 

level for the proposed standard as an 

airborne concentration of respirable 

crystalline silica of 25 mg/m3 calculated 

as an eight-hour time-weighted average. 

In this proposal, as in other standards, 

the action level has been set at one-half 

of the PEL. 

Because of the variable nature of 

employee exposures to airborne 

concentrations of respirable crystalline 

silica, maintaining exposures below the 

action level provides reasonable 

assurance that employees will not be 

exposed to respirable crystalline silica 

at levels above the PEL on days when 

no exposure measurements are made. 

Even when all measurements on a given 

day may fall below the PEL (but are 

above the action level), there is some 

chance that on another day, when 

exposures are not measured, the 

employee’s actual exposure may exceed 

the PEL. When exposure measurements 

are above the action level, the employer 

cannot be reasonably confident that 

employees have not been exposed to 

respirable crystalline silica 

concentrations in excess of the PEL 

during at least some part of the work 

week. Therefore, requiring periodic 

exposure measurements when the 

action level is exceeded provides the 

employer with a reasonable degree of 

confidence in the results of the exposure 

monitoring. 

The action level is also intended to 

encourage employers to lower exposure 

levels in order to avoid the costs 

associated with the exposure assessment 

provisions. Some employers would be 

able to reduce exposures below the 

action level in all work areas, and other 

employers in some work areas. As 

exposures are lowered, the risk of 

adverse health effects among workers 

decreases. 

OSHA’s preliminary risk assessment 

indicates that significant risk remains at 

the proposed PEL of 50 mg/m3. Where 

there is continuing significant risk, the 

decision in the Asbestos case (Bldg. and 

Constr. Trades Dep’t, AFL–CIO v. Brock, 

838 F.2d 1258, 1274 (D.C. Cir. 1988)) 

indicated that OSHA should use its 

legal authority to impose additional 

requirements on employers to further 

reduce risk when those requirements 

will result in a greater than de minimis 

incremental benefit to workers’ health. 

OSHA’s preliminary conclusion is that 

the requirements triggered by the action 

level will result in a very real and 

necessary, but non-quantifiable, further 

reduction in risk beyond that provided 

by the PEL alone. OSHA’s choice of 

proposing an action level for exposure 

monitoring of one-half of the PEL is 

based on the Agency’s successful 

experience with other standards, 

including those for inorganic arsenic (29 

CFR 1910.1018), ethylene oxide (29 CFR 

1910.1047), benzene (29 CFR 

1910.1028), and methylene chloride (29 

CFR 1910.1052). 

As specified in the proposed rule, all 

workers exposed to respirable 

crystalline silica above the PEL of 50 mg/ 

m3 are subject to the medical 

surveillance requirements. This means 

that the medical surveillance 

requirements would apply to 15,172 

workers in general industry and 336,244 

workers in construction. OSHA 

estimates that 457 possible silicosis 

cases will be referred to pulmonary 

specialists annually as a result of this 

medical surveillance. 

OSHA has preliminarily determined 

that these ancillary provisions will: (1) 

Help ensure that the PEL is not 

exceeded, and (2) minimize risk to 

workers given the very high level of risk 

remaining at the PEL. OSHA did not 

estimate, and the benefits analysis does 

not include, monetary benefits resulting 

from early discovery of illness. 

Because medical surveillance and 

exposure assessment are the two most 

costly ancillary provisions in the 

proposed rule, the Agency has 

examined four regulatory alternatives 

(named Regulatory Alternatives #3, #4, 

#5, and #6) involving changes to one or 

the other of these ancillary provisions. 

These four regulatory alternatives are 

defined below and the incremental cost 

impact of each is summarized in Table 

SI–4. In addition, OSHA is including a 

regulatory alternative (named 

Regulatory Alternative #7) that would 

remove all ancillary provisions. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Under Regulatory Alternative #3, the 

action level would be raised from 25 mg/ 

m3 to 50 mg/m3 while keeping the PEL 

at 50 mg/m3. As a result, exposure triggered only if workers were exposed 

monitoring requirements would be 


EP12SE13.003</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

13% Discount Rate I 

Proposed Rule 

Option 3: PEL=50; AL=50 

Option 4: PEL=50; AL =25, with 

medical surveillance triggered by AL 

Option 5: PEL=50; AL=25, with 

medical exams annually 

Option 6: PEL=50; AL=25, with 

surveillance triggered by AL and 

medical exams annually 

17% Discount Rate I 

Proposed Rule 

Option 3: PEL=50; AL=50 

Option 4: PEL=50; AL =25, with 

medical surveillance triggered by AL 

Option 5: PEL=50; AL=25, with 

medical exams annually 

Option 6: PEL=50; AL=25, with 

surveillance triggered by AL and 

medical exams annually 

Table 51-4: Cost of Regulatory Alternatives Affecting Ancillary Provisions 

Cost Incremental Co

Construction GIIM Total Construction 

$494,826,699 $142,502,681 $637,329,380 $457,686,162 $117,680,601 $575,366,763 -$37,140,537 -$2

$606,697,624 $173,701,827 $780,399,451 $111,870,925 $3$561,613,766 $145,088,559 $706,702,325 $66,787,067 $

$775,334,483 $203,665,685 $979,000,168 $280,507,784 $6

Cost Incremental Co

Construction GIIM Total Construction 

$511,165,616 $146,726,595 $657,892,211 $473,638,698 $121,817,396 $595,456,093 -$37,526,918 -$2

$627,197,794 $179,066,993 $806,264,787 $132,371,095 $

$575,224,843 $149,204,718 $724,429,561 $64,059,227 $

$791,806,358 $208,339,741 $1,000,146,099 $280,640,742 $6

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory A
Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56283 

above the proposed PEL of 50 mg/m3. As 

shown in Table SI–4, Regulatory Option 

#3 would reduce the annualized cost of 

the proposed rule by about $62 million, 

using a discount rate of either 3 percent 

or 7 percent. 

Under Regulatory Alternative #4, the 

action level would remain at 25 mg/m3

but medical surveillance would now be 

triggered by the action level, not the 

PEL. As a result, medical surveillance 

requirements would be triggered only if 

workers were exposed at or above the 

proposed action level of 25 mg/m3. As 

shown in Table SI–4, Regulatory Option 

#4 would increase the annualized cost 

of the proposed rule by about $143 

million, using a discount rate of 3 

percent (and by about $169 million, 

using a discount rate of 7 percent). 

Under Regulatory Alternative #5, the 

only change to the proposed rule would 

be to the medical surveillance 

requirements. Instead of requiring 

workers exposed above the PEL to have 

a medical check-up every three years, 

those workers would be required to 

have a medical check-up annually. As 

shown in Table SI–4, Regulatory Option 

#5 would increase the annualized cost 

of the proposed rule by about $69 

million, using a discount rate of 3 

percent (and by about $66 million, using 

a discount rate of 7 percent). 

Regulatory Alternative #6 would 

essentially combine the modified 

requirements in Regulatory Alternatives 

#4 and #5. Under Regulatory Alternative 

#6, medical surveillance would be 

triggered by the action level, not the 

PEL, and workers exposed at or above 

the action level would be required to 

have a medical check-up annually 

rather than triennially. The exposure 

monitoring requirements in the 

proposed rule would not be affected. As 

shown in Table SI–4, Regulatory Option 

#6 would increase the annualized cost 

of the proposed rule by about $342 

million, using a discount rate of either 

3 percent or 7 percent. 

OSHA is not able to quantify the 

effects of these preceding four 

regulatory alternatives on protecting 

workers exposed to respirable 

crystalline silica at levels at or below 

the proposed PEL of 50 mg/m3—where 

significant risk remains. The Agency 

solicits comment on the extent to which 

these regulatory options may improve or 

reduce the effectiveness of the proposed 

rule. 

The final regulatory alternative 

affecting ancillary provisions, 

Regulatory Alternative #7, would 

eliminate all of the ancillary provisions 

of the proposed rule, including 

exposure assessment, medical 

surveillance, training, and regulated 

areas or access control. However, it 

should be carefully noted that 

elimination of the ancillary provisions 

does not mean that all costs for ancillary 

provisions would disappear. In order to 

meet the PEL, employers would still 

commonly need to do monitoring, train 

workers on the use of controls, and set 

up some kind of regulated areas to 

indicate where respirator use would be 

required. It is also likely that employers 

would increasingly follow the many 

recommendations to provide medical 

surveillance for employees. OSHA has 

not attempted to estimate the extent to 

which the costs of these activities would 

be reduced if they were not formally 

required, but OSHA welcomes comment 

on the issue. 

As indicated previously, OSHA 

preliminarily finds that there is 

significant risk remaining at the 

proposed PEL of 50 mg/m3. However, the 

Agency has also preliminarily 

determined that 50 mg/m3 is the lowest 

feasible PEL. Therefore, the Agency 

believes that it is necessary to include 

ancillary provisions in the proposed 

rule to further reduce the remaining 

risk. OSHA anticipates that these 

ancillary provisions will reduce the risk 

beyond the reduction that will be 

achieved by a new PEL alone. 

OSHA’s reasons for including each of 

the proposed ancillary provisions are 

detailed in Section XVI of this 

preamble, Summary and Explanation of 

the Standards. In particular, OSHA 

believes that requirements for exposure 

assessment (or alternately, using 

specified exposure control methods for 

selected construction operations) would 

provide a basis for ensuring that 

appropriate measures are in place to 

limit worker exposures. Medical 

surveillance is particularly important 

because individuals exposed above the 

PEL (which triggers medical 

surveillance in the proposed rule) are at 

significant risk of death and illness. 

Medical surveillance would allow for 

identification of respirable crystalline 

silica-related adverse health effects at an 

early stage so that appropriate 

intervention measures can be taken. 

OSHA believes that regulated areas and 

access control are important because 

they serve to limit exposure to 

respirable crystalline silica to as few 

employees as possible. Finally, OSHA 

believes that worker training is 

necessary to inform employees of the 

hazards to which they are exposed, 

along with associated protective 

measures, so that employees understand 

how they can minimize potential health 

hazards. Worker training on silicarelated work practices is particularly 

important in controlling silica 

exposures because engineering controls 

frequently require action on the part of 

workers to function effectively. 

OSHA expects that the benefits 

estimated under the proposed rule will 

not be fully achieved if employers do 

not implement the ancillary provisions 

of the proposed rule. For example, 

OSHA believes that the effectiveness of 

the proposed rule depends on regulated 

areas or access control to further limit 

exposures and on medical surveillance 

to identify disease cases when they do 

occur. 

Both industry and worker groups have 

recognized that a comprehensive 

standard is needed to protect workers 

exposed to respirable crystalline silica. 

For example, the industry consensus 

standards for crystalline silica, ASTM E 

1132–06, Standard Practice for Health 

Requirements Relating to Occupational 

Exposure to Respirable Crystalline 

Silica, and ASTM E 2626–09, Standard 

Practice for Controlling Occupational 

Exposure to Respirable Crystalline 

Silica for Construction and Demolition 

Activities, as well as the draft proposed 

silica standard for construction 

developed by the Building and 

Construction Trades Department, AFL– 

CIO, have each included comprehensive 

programs. These recommended 

standards include provisions for 

methods of compliance, exposure 

monitoring, training, and medical 

surveillance (ASTM, 2006; 2009; BCTD 

2001). Moreover, as mentioned 

previously, where there is continuing 

significant risk, the decision in the 

Asbestos case (Bldg. and Constr. Trades 

Dep’t, AFL–CIO v. Brock, 838 F.2d 1258, 

1274 (D.C. Cir. 1988)) indicated that 

OSHA should use its legal authority to 

impose additional requirements on 

employers to further reduce risk when 

those requirements will result in a 

greater than de minimis incremental 

benefit to workers’ health. OSHA 

preliminarily concludes that the 

additional requirements in the ancillary 

provisions of the proposed standard 

clearly exceed this threshold. 

A Regulatory Alternative That Modifies 

the Methods of Compliance 

The proposed standard in general 

industry and maritime would require 

employers to implement engineering 

and work practice controls to reduce 

employees’ exposures to or below the 

PEL. Where engineering and/or work 

practice controls are insufficient, 

employers would still be required to 

implement them to reduce exposure as 

much as possible, and to supplement 

them with a respiratory protection 

program. Under the proposed 

construction standard, employers would 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56284 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

be given two options for compliance. 

The first option largely follows 

requirements for the general industry 

and maritime proposed standard, while 

the second option outlines, in Table 1 

(Exposure Control Methods for Selected 

Construction Operations) of the 

proposed rule, specific construction 

exposure control methods. Employers 

choosing to follow OSHA’s proposed 

control methods would be considered to 

be in compliance with the engineering 

and work practice control requirements 

of the proposed standard, and would 

not be required to conduct certain 

exposure monitoring activities. 

One regulatory alternative (Regulatory 

Alternative #8) involving methods of 

compliance would be to eliminate Table 

1 as a compliance option in the 

construction sector. Under that 

regulatory alternative, OSHA estimates 

that there would be no effect on 

estimated benefits but that the 

annualized costs of complying with the 

proposed rule (without the benefit of the 

Table 1 option in construction) would 

increase by $175 million, totally in 

exposure monitoring costs, using a 3 

percent discount rate (and by $178 

million using a 7 percent discount rate), 

so that the total annualized compliance 

costs for all affected establishments in 

construction would increase from $495 

to $670 million using a 3 percent 

discount rate (and from $511 to $689 

million using a 7 percent discount rate). 

Regulatory Alternatives That Affect the 

Timing of the Standard 

The proposed rule would become 

effective 60 days following publication 

of the final rule in the Federal Register. 

Provisions outlined in the proposed 

standard would become enforceable 180 

days following the effective date, with 

the exceptions of engineering controls 

and laboratory requirements. The 

proposed rule would require 

engineering controls to be implemented 

no later than one year after the effective 

date, and laboratory requirements 

would be required to begin two years 

after the effective date. 

OSHA will strongly consider 

alternatives that would reduce the 

economic impact of the rule and 

provide additional flexibility for firms 

coming into compliance with the 

requirements of the rule. The Agency 

solicits comment and suggestions from 

stakeholders, particularly small 

business representatives, on options for 

phasing in requirements for engineering 

controls, medical surveillance, and 

other provisions of the rule (e.g., over 1, 

2, 3, or more years). These options will 

be considered for specific industries 

(e.g., industries where first-year or 

annualized cost impacts are highest), 

specific size-classes of employers (e.g., 

employers with fewer than 20 

employees), combinations of these 

factors, or all firms covered by the rule. 

Although OSHA did not explicitly 

develop or quantitatively analyze the 

multitude of potential regulatory 

alternatives involving longer-term or 

more complex phase-ins of the standard, 

the Agency is soliciting comments on 

this issue. Such a particularized, multiyear phase-in could have several 

advantages, especially from the 

viewpoint of impacts on small 

businesses. First, it would reduce the 

one-time initial costs of the standard by 

spreading them out over time, a 

particularly useful mechanism for small 

businesses that have trouble borrowing 

large amounts of capital in a single year. 

Second, a differential phase-in for 

smaller firms would aid very small 

firms by allowing them to gain from the 

control experience of larger firms. 

Finally, a phase-in would be useful in 

certain industries—such as foundries, 

for example—by allowing employers to 

coordinate their environmental and 

occupational safety and health control 

strategies to minimize potential costs. 

However a phase-in would also 

postpone the benefits of the standard. 

OSHA analyzed one regulatory 

alternative (Regulatory Alternative #9) 

involving the timing of the standard 

which would arise if, contrary to 

OSHA’s preliminary findings, a PEL of 

50 mg/m3 with an action level of 25 mg/ 

m3 were found to be technologically and 

economically feasible some time in the 

future (say, in five years), but not 

feasible immediately. In that case, 

OSHA might issue a final rule with a 

PEL of 50 mg/m3 and an action level of 

25 mg/m3 to take effect in five years, but 

at the same time issue an interim PEL 

of 100 mg/m3 and an action level of 50 

mg/m3 to be in effect until the final rule 

becomes feasible. Under this regulatory 

alternative, and consistent with the 

public participation and ‘‘look back’’ 

provisions of Executive Order 13563, 

the Agency could monitor compliance 

with the interim standard, review 

progress toward meeting the feasibility 

requirements of the final rule, and 

evaluate whether any adjustments to the 

timing of the final rule would be 

needed. Under Regulatory Alternative 

#9, the estimated costs and benefits 

would be somewhere between those 

estimated for a PEL of 100 mg/m3 with 

an action level of 50 mg/m3 and those 

estimated for a PEL of 50 mg/m3 with an 

action level of 25 mg/m3, the exact 

estimates depending on the length of 

time until the final rule is phased in. 

OSHA emphasizes that this regulatory 

alternative is contrary to the Agency’s 

preliminary findings of economic 

feasibility and, for the Agency to 

consider it, would require specific 

evidence introduced on the record to 

show that the proposed rule is not now 

feasible but would be feasible in the 

future. 

OSHA requests comments on these 

regulatory alternatives, including the 

Agency’s choice of regulatory 

alternatives (and whether there are other 

regulatory alternatives the Agency 

should consider) and the Agency’s 

analysis of them. 

I. Issues 

OSHA requests comment on all 

relevant issues, including health effects, 

risk assessment, significance of risk, 

technological and economic feasibility, 

and the provisions of the proposed 

regulatory text. In addition, OSHA 

requests comments on all of the issues 

raised by the Small Business Regulatory 

Fairness Enforcement Act (SBREFA) 

Panel, as summarized in Table VIII–H– 

4 in Section VIII.H of this preamble. 

OSHA is including Section I on issues 

at the beginning of the document to 

assist readers as they review the 

proposal and consider any comments 

they may want to submit. However, to 

fully understand the questions in this 

section and provide substantive input in 

response to them, the parts of the 

preamble that address these issues in 

detail should be read and reviewed. 

These include: Section V, Health Effects 

Summary; Section VI, Summary of the 

Preliminary Quantitative Risk 

Assessment; Section VII, Significance of 

Risk; Section VIII, Summary of the 

Preliminary Economic Analysis and 

Initial Regulatory Flexibility Analysis; 

and Section XVI, Summary and 

Explanation of the Standards. In 

addition, OSHA invites comment on 

additional technical questions and 

discussions of economic issues 

presented in the Preliminary Economic 

Analysis (PEA) of the proposed 

standards. Section XIX is the text of the 

standards and is the final authority on 

what is required in them. 

OSHA requests that comments be 

organized, to the extent possible, around 

the following issues and numbered 

questions. Comment on particular 

provisions should contain a heading 

setting forth the section and the 

paragraph in the standard that the 

comment is addressing. Comments 

addressing more than one section or 

paragraph will have correspondingly 

more headings. 

Submitting comments in an organized 

manner and with clear reference to the 

issue raised will enable all participants 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56285 

to easily see what issues the commenter 

addressed and how they were 

addressed. This is particularly 

important in a rulemaking such as 

silica, which has multiple adverse 

health effects and affects many diverse 

processes and industries. Many 

commenters, especially small 

businesses, are likely to confine their 

interest (and comments) to the issues 

that affect them, and they will benefit 

from being able to quickly identify 

comments on these issues in others’ 

submissions. Of course, the Agency 

welcomes comments concerning this 

proposal that fall outside the issues 

raised in this section. However, OSHA 

is especially interested in responses, 

supported by evidence and reasons, to 

the following questions: 

Health Effects 

1. OSHA has described a variety of 

studies addressing the major adverse 

health effects that have been associated 

with exposure to respirable crystalline 

silica. Has OSHA adequately identified 

and documented all critical health 

impairments associated with 

occupational exposure to respirable 

crystalline silica? If not, what adverse 

health effects should be added? Are 

there any additional studies, other data, 

or information that would affect the 

information discussed or significantly 

change the determination of material 

health impairment? Submit any relevant 

information, data, or additional studies 

(or the citations), and explain your 

reasoning for recommending the 

inclusion of any studies you suggest. 

2. Using currently available 

epidemiologic and experimental 

studies, OSHA has made a preliminary 

determination that respirable crystalline 

silica presents risks of lung cancer, 

silicosis, and non-malignant respiratory 

disease (NMRD) as well as autoimmune 

and renal disease risks to exposed 

workers. Is this determination correct? 

Are there additional studies or other 

data OSHA should consider in 

evaluating any of these adverse health 

risks? If so, submit the studies (or 

citations) and other data and include 

your reasons for finding them germane 

to determining adverse health effects of 

exposure to crystalline silica. 

Risk Assessment 

3. OSHA has relied upon risk models 

using cumulative respirable crystalline 

silica exposure to estimate the lifetime 

risk of death from occupational lung 

cancer, silicosis, and NMRD among 

exposed workers. Additionally, OSHA 

has estimated the lifetime risk of 

silicosis morbidity among exposed 

workers. Is cumulative exposure the 

correct metric for exposure for each of 

these models? If not, what exposure 

measure should be used? 

4. Some of the literature OSHA 

reviewed indicated that the risk of 

contracting accelerated silicosis and 

lung cancer may be non-linear at very 

high exposures and may be described by 

an exposure dose rate health effect 

model. OSHA used the more 

conservative model of cumulative 

exposure that is more protective to the 

worker. Are there additional data to 

support or rebut any of these models 

used by OSHA? Are there other models 

that OSHA should consider for 

estimating lung cancer, silicosis, or 

NMRD risk? If so, describe the models 

and the rationale for their use. 

5. Are there additional studies or 

sources of data that OSHA should have 

included in its qualitative and 

quantitative risk assessments? What are 

these studies and have they been peerreviewed, or are they soon to be peerreviewed? What is the rationale for 

recommending the studies or data? 

6. Steenland et al. (2001a) pooled data 

from 10 cohort studies to conduct an 

analysis of lung cancer mortality among 

silica-exposed workers. Can you provide 

quantitative lung cancer risk estimates 

from other data sources? Have or will 

the data you submit be peer-reviewed? 

OSHA is particularly interested in 

quantitative risk analyses that can be 

conducted using the industrial sand 

worker studies by McDonald, Hughes, 

and Rando (2001) and the pooled 

center-based case-control study 

conducted by Cassidy et al. (2007). 

7. OSHA has made a preliminary 

determination that the available data are 

not sufficient or suitable for quantitative 

analysis of the risk of autoimmune 

disease, stomach cancer, and other 

cancer and non-cancer health effects. Do 

you have, or are you aware of, studies, 

data, and rationale that would be 

suitable for a quantitative risk 

assessment for these adverse health 

effects? Submit the studies (or citations), 

data, and rationale. 

Profile of Affected Industries 

8. In its PEA of the proposed rule, 

summarized in Section VIII of this 

preamble, OSHA presents a profile of 

the affected worker population. The 

profile includes estimates of the number 

of affected workers by industry sector or 

operation and job category, and the 

distribution of exposures by job 

category. If your company has potential 

worker exposures to respirable 

crystalline silica, is your industry 

among those listed by North American 

Industry Classification System (NAICS) 

code as affected industries? Are there 

additional data that will enable the 

Agency to refine its profile of the worker 

population exposed to respirable 

crystalline silica? If so, provide or 

reference such data and explain how 

OSHA should use these data to revise 

the profile. 

Technological and Economic Feasibility 

of the Proposed PEL 

9. What are the job categories in 

which employees are potentially 

exposed to respirable crystalline silica 

in your company or industry? For each 

job category, provide a brief description 

of the operation and describe the job 

activities that may lead to respirable 

crystalline silica exposure. How many 

employees are exposed, or have the 

potential for exposure, to respirable 

crystalline silica in each job category in 

your company or industry? What are the 

frequency, duration, and levels of 

exposures to respirable crystalline silica 

in each job category in your company or 

industry? Where responders are able to 

provide exposure data, OSHA requests 

that, where available, exposure data be 

personal samples with clear 

descriptions of the length of the sample, 

analytical method, and controls in 

place. Exposure data that provide 

information concerning the controls in 

place are more valuable than exposure 

data without such information. 

10. Please describe work 

environments or processes that may 

expose workers to cristobalite. Please 

provide supporting evidence, or explain 

the basis of your knowledge. 

11. Have there been technological 

changes within your industry that have 

influenced the magnitude, frequency, or 

duration of exposure to respirable 

crystalline silica or the means by which 

employers attempt to control such 

exposures? Describe in detail these 

technological changes and their effects 

on respirable crystalline silica 

exposures and methods of control. 

12. Has there been a trend within your 

industry or an effort in your firm to 

reduce or eliminate respirable 

crystalline silica from production 

processes, products, and services? If so, 

please describe the methods used and 

provide an estimate of the percentage 

reduction in respirable crystalline silica, 

and the extent to which respirable 

crystalline silica is still necessary in 

specific processes within product lines 

or production activities. If you have 

substituted another substance(s) for 

crystalline silica, identify the 

substance(s) and any adverse health 

effects associated with exposure to the 

substitute substances, and the cost 

impact of substitution (cost of materials, 

productivity impact). OSHA also 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56286 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

requests that responders describe any 

health hazards or technical, economic, 

or other deterrents to substitution. 

13. Has your industry or firm used 

outsourcing or subcontracting, or 

concentrated high exposure tasks inhouse, in order to expose fewer workers 

to respirable crystalline silica? An 

example would be subcontracting for 

the removal of hardened concrete from 

concrete mixing trucks, a task done 

typically 2–4 times a year, to a specialty 

subcontractor. What methods have you 

used to reduce the number of workers 

exposed to respirable crystalline silica 

and how were they implemented? 

Describe any trends related to 

concentration of high exposure tasks 

and provide any supporting 

information. 

14. Does any job category or employee 

in your workplace have exposures to 

respirable crystalline silica that air 

monitoring data do not adequately 

portray due to the short duration, 

intermittent or non-routine nature, or 

other unique characteristics of the 

exposure? Explain your response and 

indicate peak levels, duration, and 

frequency of exposures for employees in 

these job categories. 

15. OSHA requests the following 

information regarding engineering and 

work practice controls to control 

exposure to crystalline silica in your 

workplace or industry: 

a. Describe the operations and tasks in 

which the proposed PEL is being 

achieved most of the time by means of 

engineering and work practice controls. 

b. What engineering and work 

practice controls have been 

implemented in these operations and 

tasks? 

c. For all operations and tasks in 

facilities where respirable crystalline 

silica is used, what engineering and 

work practice controls have been 

implemented to control respirable 

crystalline silica? If you have installed 

engineering controls or adopted work 

practices to reduce exposure to 

respirable crystalline silica, describe the 

exposure reduction achieved and the 

cost of these controls. 

d. Where current work practices 

include the use of regulated areas and 

hygiene facilities, provide data on the 

implementation of these controls, 

including data on the costs of 

installation, operation, and maintenance 

associated with these controls. 

e. Describe additional engineering and 

work practice controls that could be 

implemented in each operation where 

exposure levels are currently above the 

proposed PEL to further reduce 

exposure levels. 

f. When these additional controls are 

implemented, to what levels can 

exposure be expected to be reduced, or 

what percent reduction is expected to be 

achieved? 

g. What amount of time is needed to 

develop, install, and implement these 

additional controls? Will the added 

controls affect productivity? If so, how? 

h. Are there any processes or 

operations for which it is not reasonably 

possible to implement engineering and 

work practice controls within one year 

to achieve the proposed PEL? If so, how 

much additional time would be 

necessary? 

16. OSHA requests information on 

whether there are any specific 

conditions or job tasks involving 

exposure to respirable crystalline silica 

where engineering and work practice 

controls are not available or are not 

capable of reducing exposure levels to 

or below the proposed PEL most of the 

time. Provide data and evidence to 

support your response. 

17. OSHA has made a preliminary 

determination that compliance with the 

proposed PEL can be achieved in most 

operations most of the time through the 

use of engineering and work practice 

controls. OSHA has further made a 

preliminary determination that the 

proposed rule is technologically 

feasible. OSHA solicits comments on 

the reasonableness of these preliminary 

determinations. 

Compliance Costs 

18. In its PEA (summarized in Section 

VIII.3 of this preamble), OSHA 

developed its estimate of the costs of the 

proposed rule. The Agency requests 

comment on the methodological and 

analytical assumptions applied in the 

cost analysis. Of particular importance 

are the unit cost estimates provided in 

tables and text in Chapter V of the PEA 

for all major provisions of the proposed 

rule. OSHA requests the following 

information regarding unit and total 

compliance costs: 

a. If you have installed engineering 

controls or adopted work practices to 

reduce exposure to respirable crystalline 

silica, describe these controls and their 

costs. If you have substituted another 

substance(s) for crystalline silica, what 

has been the cost impact of substitution 

(cost of materials, productivity impact)? 

b. OSHA has proposed to limit the 

prohibition on dry sweeping to 

situations where this activity could 

contribute to exposure that exceeds the 

PEL and estimated the costs for the use 

of wet methods to control dust. OSHA 

requests comment on the use of wet 

methods as a substitute for dry 

sweeping and whether the prohibition 

on dry sweeping is feasible and costeffective. 

c. In its PEA, OSHA presents 

estimated baseline levels of use of 

personal protective equipment (PPE) 

and the incremental PPE costs 

associated with the proposed rule. Are 

OSHA’s estimated PPE compliance rates 

reasonable? Are OSHA’s estimates of 

PPE costs, and the assumptions 

underlying these estimates, consistent 

with current industry practice? If not, 

provide data and evidence describing 

current industry PPE practices. 

d. Do you currently conduct exposure 

monitoring for respirable crystalline 

silica? Are OSHA’s estimates of 

exposure assessment costs reasonable? 

Would your company require outside 

consultants to perform exposure 

monitoring? 

e. Are OSHA’s estimates for medical 

surveillance costs—including direct 

medical costs, the opportunity cost of 

worker time for offsite travel and for the 

health screening, and recordkeeping 

costs—reasonable? 

f. In its PEA, OSHA presents 

estimated baseline levels of training and 

information concerning respirable 

crystalline silica-related hazards and the 

incremental costs associated with the 

additional requirements for training and 

information in the proposed rule. OSHA 

requests information on information and 

training programs addressing respirable 

crystalline silica that are currently being 

implemented by employers and any 

necessary additions to those programs 

that are anticipated in response to the 

proposed rule. Are OSHA’s baseline 

estimates and unit costs for training 

reasonable and consistent with current 

industry practice? 

g. Are OSHA’s estimated costs for 

regulated areas and written access 

control plans reasonable? 

h. The cost estimates in the PEA take 

the much higher labor turnover rates in 

construction into account when 

calculating costs. For the proposed rule, 

OSHA used the most recent BLS 

turnover rate of 64 percent for 

construction (versus a turnover rate of 

27.2 percent for general industry). 

OSHA believes that the estimates in the 

PEA capture the effect of high turnover 

rates in construction and solicits 

comments on this issue. 

i. Has OSHA omitted any costs that 

would be incurred to comply with the 

proposed rule? 

Effects on Small Entities 

19. OSHA has considered the effects 

on small entities raised during its 

SBREFA process and addressed these 

concerns in Chapter VIII of the PEA. Are 

there additional difficulties small 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56287 

entities may encounter when attempting 

to comply with requirements of the 

proposed rule? Can any of the 

proposal’s requirements be deleted or 

simplified for small entities, while still 

providing equivalent protection of the 

health of employees? Would allowing 

additional time for small entities to 

comply make a difference in their 

ability to comply? How much additional 

time would be necessary? 

Economic Impacts 

20. OSHA, in its PEA, has estimated 

compliance costs per affected entity and 

the likely impacts on revenues and 

profits. OSHA requests that affected 

employers provide comment on OSHA’s 

estimate of revenue, profit, and the 

impacts of costs for their industry or 

application group. The Agency also 

requests that employers provide data on 

their revenues, profits, and the impacts 

of cost, if available. Are there special 

circumstances—such as unique cost 

factors, foreign competition, or pricing 

constraints—that OSHA needs to 

consider when evaluating economic 

impacts for particular applications and 

industry groups? 

21. OSHA seeks comment as to 

whether establishments will be able to 

finance first-year compliance costs from 

cash flow, and under what 

circumstances a phase-in approach will 

assist firms in complying with the 

proposed rule. 

22. The Agency invites comment on 

potential employment impacts of the 

proposed silica rule, and on Inforum’s 

estimates of the employment impacts of 

the proposed silica rule on the U.S. 

economy. 

Outreach and Compliance Assistance 

23. If the proposed rule is 

promulgated, OSHA will provide 

outreach materials on the provisions of 

the standards in order to encourage and 

assist employers in complying. Are 

there particular materials that would 

make compliance easier for your 

company or industry? What materials 

would be especially useful for small 

entities? Submit recommendations or 

samples. 

Benefits and Net Benefits 

24. OSHA requests comments on any 

aspect of its estimation of benefits and 

net benefits from the proposed rule, 

including the following: 

a. The use of willingness-to-pay 

measures and estimates based on 

compensating wage differentials. 

b. The data and methods used in the 

benefits calculations. 

c. The choice of discount rate for 

annualizing the monetized benefits of 

the proposed rule. 

d. Increasing the monetary value of a 

statistical life over time resulting from 

an increase in real per capita income 

and the estimated income elasticity of 

the value of life. 

e. Extending the benefits analysis 

beyond the 60-year period used in the 

PEA. 

f. The magnitude of non-quantified 

health benefits arising from the 

proposed rule and methods for better 

measuring these effects. An example 

would be diagnosing latent tuberculosis 

(TB) in the silica-exposed population 

and thereby reducing the risk of TB 

being spread to the population at large. 

Overlapping and Duplicative 

Regulations 

25. Do any federal regulations 

duplicate, overlap, or conflict with the 

proposed respirable crystalline silica 

rule? If so, provide or cite to these 

regulations. 

Alternatives/Ways to Simplify a New 

Standard 

26. Comment on the alternative to 

new comprehensive standards (which 

have ancillary provisions in addition to 

a permissible exposure limit) that would 

be simply improved outreach and 

enforcement of the existing standards 

(which is only a permissible exposure 

limit with no ancillary provisions). Do 

you believe that improved outreach and 

enforcement of the existing permissible 

exposure limits would be sufficient to 

reduce significant risks of material 

health impairment in workers exposed 

to respirable crystalline silica? Provide 

information to support your position. 

27. OSHA solicits comments on ways 

to simplify the proposed rule without 

compromising worker protection from 

exposure to respirable crystalline silica. 

In particular, provide detailed 

recommendations on ways to simplify 

the proposed standard for construction. 

Provide evidence that your 

recommended simplifications would 

result in a standard that was effective, 

to the extent feasible, in reducing 

significant risks of material health 

impairment in workers exposed to 

respirable crystalline silica. 

Environmental Impacts 

28. Submit data, information, or 

comments pertaining to possible 

environmental impacts of adopting this 

proposal, including any positive or 

negative environmental effects and any 

irreversible commitments of natural 

resources that would be involved. In 

particular, consideration should be 

given to the potential direct or indirect 

impacts of the proposal on water and air 

pollution, energy use, solid waste 

disposal, or land use. Would 

compliance with the silica rule require 

additional actions to comply with 

federal, state, or local environmental 

requirements? 

29. Some small entity representatives 

advised OSHA that the use of water as 

a control measure is limited at their 

work sites due to potential water and 

soil contamination. OSHA believes 

these limits may only apply in 

situations where crystalline silica is 

found with other toxic substances such 

as during abrasive blasting of metal or 

painted metal structures, or in locations 

where state and local requirements are 

more restrictive than EPA requirements. 

OSHA seeks comments on this issue, 

including cites to applicable 

requirements. 

a. Are there limits on the use of water 

controls in your operations due to 

environmental regulations? If so, are the 

limits due to the non-silica components 

of the waste stream? What are these 

non-silica components? 

b. What metals or other toxic 

chemicals are in your silica waste 

streams and what are the procedures 

and costs to filter out these metals or 

other toxic chemicals from your waste 

streams? Provide documentation to 

support your cost estimates. 

Provisions of the Standards 

Scope 

30. OSHA’s Advisory Committee on 

Construction Safety and Health 

(ACCSH) has historically advised the 

Agency to take into consideration the 

unique nature of construction work 

environments by either setting separate 

standards or making accommodations 

for the differences in work 

environments in construction as 

compared to general industry. ASTM, 

for example, has separate silica 

standards of practice for general 

industry and construction, E 1132–06 

and E 2625–09, respectively. To account 

for differences in the workplace 

environments for these different sectors, 

OSHA has proposed separate standards 

for general industry/maritime and 

construction. Is this approach necessary 

and appropriate? What other 

approaches, if any, should the Agency 

consider? Provide a rationale for your 

response. 

31. OSHA has proposed that the scope 

of the construction standard include all 

occupational exposures to respirable 

crystalline silica in construction work as 

defined in 29 CFR 1910.12(b) and 

covered under 29 CFR part 1926, rather 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56288 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

than restricting the application of the 

rule to specific construction operations. 

Should OSHA modify the scope to limit 

what is covered? What should be 

included and what should be excluded? 

Provide a rationale for your position. 

Submit your proposed language for the 

scope and application provision. 

32. OSHA has not proposed to cover 

agriculture because the Agency does not 

have data sufficient to determine the 

feasibility of the proposed PEL in 

agricultural operations. Should OSHA 

cover respirable crystalline silica 

exposure in agriculture? Provide 

evidence to support your position. 

OSHA seeks information on agricultural 

operations that involve respirable 

crystalline silica exposures, including 

information that identifies particular 

activities or crops (e.g., hand picking 

fruit and vegetables, shaking branches 

and trees, harvesting with combines, 

loading storage silos, planting) 

associated with exposure, information 

indicating levels of exposure, and 

information relating to available control 

measures and their effectiveness. OSHA 

also seeks information related to the 

development of respirable crystalline 

silica-related adverse health effects and 

diseases among workers in the 

agricultural sector. 

33. Should OSHA limit coverage of 

the rule to materials that contain a 

threshold concentration (e.g., 1%) of 

crystalline silica? For example, OSHA’s 

Asbestos standard defines ‘‘asbestoscontaining material’’ as any material 

containing more than 1% asbestos, for 

consistency with EPA regulations. 

OSHA has not proposed a comparable 

limitation to the definition of respirable 

crystalline silica. Is this approach 

appropriate? Provide the rationale for 

your position. 

34. OSHA has proposed to cover 

shipyards under the general industry 

standard. Are there any unique 

circumstances in shipyard employment 

that would justify development of 

different provisions or a separate 

standard for the shipyard industry? 

What are the circumstances and how 

would they not be adequately covered 

by the general industry standard? 

Definitions 

35. Competent person. OSHA has 

proposed limited duties for a competent 

person relating to establishment of an 

access control plan. The Agency did not 

propose specific requirements for 

training of a competent person. Is this 

approach appropriate? Should OSHA 

include a competent person provision? 

If so, should the Agency add to, modify, 

or delete any of the duties of a 

competent person as described in the 

proposed standard? Provide the basis for 

your recommendations. 

36. Has OSHA defined ‘‘respirable 

crystalline silica’’ appropriately? If not, 

provide the definition that you believe 

is appropriate. Explain the basis for 

your response, and provide any data 

that you believe are relevant. 

37. The proposed rule defines 

‘‘respirable crystalline silica’’ in part as 

‘‘airborne particles that contain quartz, 

cristobalite, and/or tridymite.’’ OSHA 

believes that tridymite is rarely found in 

nature or in the workplace. Please 

describe any instances of occupational 

exposure to tridymite of which you are 

aware. Please provide supporting 

evidence, or explain the basis of your 

knowledge. Should tridymite be 

included in the scope of this proposed 

rule? Please provide any evidence to 

support your position. 

PEL and Action Level 

38. OSHA has proposed a TWA PEL 

for respirable crystalline silica of 50 mg/ 

m3 for general industry, maritime, and 

construction. The Agency has made a 

preliminary determination that this is 

the lowest level that is technologically 

feasible. The Agency has also 

determined that a PEL of 50 mg/m3 will 

substantially reduce, but not eliminate, 

significant risk of material health 

impairment. Is this PEL appropriate, 

given the Agency’s obligation to reduce 

significant risk of material health 

impairment to the extent feasible? If not, 

what PEL would be more appropriate? 

The Agency also solicits comment on 

maintaining the existing PELs for 

respirable crystalline silica. Provide 

evidence to support your response. 

39. OSHA has proposed a single PEL 

for respirable crystalline silica (quartz, 

cristobalite, and tridymite). Is a single 

PEL appropriate, or should the Agency 

maintain separate PELs for the different 

forms of respirable crystalline silica? 

Provide the rationale for your position. 

40. OSHA has proposed an action 

level for respirable crystalline silica 

exposure of 25 mg/m3 in general 

industry, maritime, and construction. Is 

this an appropriate approach and level, 

and if not, what approach or level 

would be more appropriate and why? 

Should an action level be included in 

the final rule? Provide the rationale for 

your position. 

41. If an action level is included in 

the final rule, which provisions, if any, 

should be triggered by exposure above 

or below the action level? Provide the 

basis for your position and include 

supporting information. 

42. If no action level is included in 

the final rule, which provisions should 

apply to all workers exposed to 

respirable crystalline silica? Which 

provisions should be triggered by the 

PEL? Are there any other appropriate 

triggers for the requirements of the rule? 

Exposure Assessment 

43. OSHA is proposing to allow 

employers to initially assess employee 

exposures using air monitoring or 

objective data. Has OSHA defined 

‘‘objective data’’ sufficiently for an 

employer to know what data may be 

used? If not, submit an alternative 

definition. Is it appropriate to allow 

employers to use objective data to 

perform exposure assessments? Explain 

why or why not. 

44. The proposed rule provides two 

options for periodic exposure 

assessment: (1) A fixed schedule option, 

and (2) a performance option. The 

performance option provides employers 

flexibility in the methods used to 

determine employee exposures, but 

requires employers to accurately 

characterize employee exposures. The 

proposed approach is explained in the 

Summary and Explanation for 

paragraph (d) Exposure Assessment. 

OSHA solicits comments on this 

proposed exposure assessment 

provision. Is the wording of the 

performance option in the regulatory 

text understandable and does it clearly 

indicate what would constitute 

compliance with the provision? If not, 

suggest alternative language that would 

clarify the provision, enabling 

employers to more easily understand 

what would constitute compliance. 

45. Do you conduct initial air 

monitoring or do you rely on objective 

data to determine respirable crystalline 

silica exposures? If objective data, what 

data do you use? Have you conducted 

historical exposure monitoring of your 

workforce that is representative of 

current process technology and 

equipment use? Describe any other 

approaches you have implemented for 

assessing an employee’s initial exposure 

to respirable crystalline silica. 

46. OSHA is proposing specific 

requirements for laboratories that 

perform analyses of respirable 

crystalline silica samples. The rationale 

is to improve the precision in individual 

laboratories and reduce the variability of 

results between laboratories, so that 

sampling results will be more reliable. 

Are these proposed requirements 

appropriate? Will the laboratory 

requirements add necessary reliability 

and reduce inter-lab variability, or 

might they be overly proscriptive? 

Provide the basis for your response. 

47. Has OSHA correctly described the 

accuracy and precision of existing 

methods of sampling and analysis for 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56289 

respirable crystalline silica at the 

proposed action level and PEL? Can 

worker exposures be accurately 

measured at the proposed action level 

and PEL? Explain the basis for your 

response, and provide any data that you 

believe are relevant. 

48. OSHA has not addressed the 

performance of the analytical method 

with respect to tridymite since we have 

found little available data. Please 

comment on the performance of the 

analytical method with respect to 

tridymite and provide any data to 

support your position. 

Regulated Areas and Access Control 

49. Where exposures exceed the PEL, 

OSHA has proposed to provide 

employers with the option of either 

establishing a regulated area or 

establishing a written access control 

plan. For which types of work 

operations would employers be likely to 

establish a written access control plan? 

Will employees be protected by these 

options? Provide the basis for your 

position and include supporting 

information. 

50. The Summary and Explanation for 

paragraph (e) Regulated Areas and 

Access Control clarifies how the 

regulated area requirements would 

apply to multi-employer worksites in 

the proposed standard. OSHA solicits 

comments on this issue. 

51. OSHA is proposing limited 

requirements for protective clothing in 

the silica rule. Is this appropriate? Are 

you aware of any situations where more 

or different protective clothing would be 

needed for silica exposures? If so, what 

type of protective clothing and 

equipment should be required? Are 

there additional provisions related to 

protective clothing that should be 

incorporated into this rule that will 

enhance worker protection? Provide the 

rationale and data that support your 

conclusions. 

Methods of Compliance 

52. In OSHA’s cadmium standard (29 

CFR 1910.1027(f)(1)(ii),(iii), and (iv)), 

the Agency established separate 

engineering control air limits (SECALs) 

for certain processes in selected 

industries. SECALs were established 

where compliance with the PEL by 

means of engineering and work practice 

controls was infeasible. For these 

industries, a SECAL was established at 

the lowest feasible level that could be 

achieved by engineering and work 

practice controls. The PEL was set at a 

lower level, and could be achieved by 

any allowable combination of controls, 

including respiratory protection. In 

OSHA’s chromium (VI) standard (29 

CFR 1910.1026), an exception similar to 

SECALs was made for painting 

airplanes and airplane parts. Should 

OSHA follow this approach for 

respirable crystalline silica in any 

industries or processes? If so, in what 

industries or processes, and at what 

exposure levels, should the SECALs be 

established? Provide the basis for your 

position and include supporting 

information. 

53. The proposed standards do not 

contain a requirement for a written 

exposure control program. The two 

ASTM standards for general industry 

and construction (E 1132–06, section 

4.2.6, and E 2626–09, section 4.2.5) state 

that, where overexposures are persistent 

(such as in regulated areas or abrasive 

blasting operations), a written exposure 

control plan shall establish engineering 

and administrative controls to bring the 

area into compliance, if feasible. In 

addition, the proposed regulatory 

language developed by the Building and 

Construction Trades Department, AFL– 

CIO contains provisions for a written 

program. The ASTM standards 

recommend that, where there are 

regulated areas with persistent 

exposures or tasks, tools, or operations 

that tend to cause respirable crystalline 

silica exposure, the employer will 

conduct a formal analysis and 

implement a written control plan (an 

abatement plan) on how to bring the 

process into compliance. If that is not 

feasible, the employer is to indicate the 

respiratory protection and other 

protective procedures that will be used 

to protect employee(s) permanently or 

until compliance will be achieved. 

Should OSHA require employers to 

develop and implement a written 

exposure control plan and, if so, what 

should be required to be in the plans? 

54. Table 1 in the proposed 

construction standard specifies 

engineering and work practice controls 

and respiratory protection for selected 

construction operations, and exempts 

employers who implement these 

controls from exposure assessment 

requirements. Is this approach 

appropriate? Are there other operations 

that should be included, or listed 

operations that should not be included? 

Are the specified control measures 

effective? Should any other changes be 

made in Table 1? How should OSHA 

update Table 1 in the future to account 

for development of new technologies? 

Provide data and information to support 

your position. 

55. OSHA requests comments on the 

degree of specificity used for the 

engineering and work practice controls 

for tasks identified in Table 1, including 

maintenance requirements. Should 

OSHA require an evaluation or 

inspection checklist for controls? If so, 

how frequently should evaluations or 

inspections be conducted? Provide any 

examples of such checklists, along with 

information regarding their frequency of 

use and effectiveness. 

56. In the proposed construction 

standard, when employees perform an 

operation listed in Table 1 and the 

employer fully implements the 

engineering controls, work practices, 

and respiratory protection described in 

Table 1 for that operation, the employer 

is not required to assess the exposure of 

the employees performing such 

operations. However, the employer must 

still ensure compliance with the 

proposed PEL for that operation. OSHA 

seeks comment on whether employers 

fully complying with Table 1 for an 

operation should still need to comply 

with the proposed PEL for that 

operation. Instead, should OSHA treat 

compliance with Table 1 as 

automatically meeting the requirements 

of the proposed PEL? 

57. Are the descriptions of the 

operations (specific task or tool 

descriptions) and control technologies 

in Table 1 clear and precise enough so 

that employers and workers will know 

what controls they should be using for 

the listed operations? Identify the 

specific operation you are addressing 

and whether your assessment is based 

on your anecdotal experience or 

research. For each operation, are the 

data and other supporting information 

sufficient to predict the range of 

expected exposures under the 

controlled conditions? Identify 

operations, if any, where you believe the 

data are not sufficient. Provide the 

reasoning and data that support your 

position. 

58. In one specific example from 

Table 1, OSHA has proposed the option 

of using a wet method for hand-operated 

grinders, with respirators required only 

for operations lasting four hours or 

more. Please comment and provide 

OSHA with additional information 

regarding wet grinding and the 

adequacy of this control strategy. OSHA 

is also seeking additional information 

on the second option (commercially 

available shrouds and dust collection 

systems) to confirm that this control 

strategy (including the use of half-mask 

respirators) will reduce workers’ 

exposure to or below the PEL. 

59. For impact drilling operations 

lasting four hours or less, OSHA is 

proposing in Table 1 to allow workers 

to use water delivery systems without 

the use of respiratory protection, as the 

Agency believes that this dust 

suppression method alone will provide 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56290 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

consistent, sufficient protection. Is this 

control strategy appropriate? Please 

provide the basis for your position and 

any supporting evidence or additional 

information that addresses the 

appropriateness of this control strategy. 

60. In the case of rock drilling, in 

order to ensure that workers are 

adequately protected from the higher 

exposures that they would experience 

working under shrouds, OSHA is 

proposing in Table 1 that employers 

ensure that workers use half-mask 

respirators when working under 

shrouds at the point of operation. Is this 

specification appropriate? Please 

provide the basis for your position and 

any supporting evidence or additional 

information that addresses the 

appropriateness of this specification. 

61. OSHA has specified a control 

strategy for concrete drilling in Table 1 

that includes use of a dust collection 

system as well as a low-flow water 

spray. Please provide to OSHA any data 

that you have that describes the efficacy 

of these controls. Is the control strategy 

in Table 1 adequate? Please provide the 

basis for your position and any 

supporting evidence or additional 

information regarding the adequacy of 

this control strategy. 

62. One of the control options in 

Table 1 in the proposed construction 

standard for rock-crushing operations is 

local exhaust ventilation. However, 

OSHA is aware of difficulties in 

applying this control to this operation. 

Is this control strategy appropriate and 

practical for rock-crushing operations? 

Please provide any information that you 

have addressing this issue. 

63. OSHA has not proposed to 

prohibit the use of crystalline silica as 

an abrasive blasting agent. Abrasive 

blasting, similar to other operations that 

involve respirable crystalline silica 

exposures, must follow the hierarchy of 

controls, which means, if feasible, that 

substitution, engineering, or 

administrative controls or a 

combination of these controls must be 

used to minimize or eliminate the 

exposure hazard. Is this approach 

appropriate? Provide the basis for your 

position and any supporting evidence. 

64. The technological feasibility study 

(PEA, Chapter 4) indicates that 

employers use substitutes for crystalline 

silica in a variety of operations. If you 

are aware of substitutes for crystalline 

silica that are currently being used in 

any operation not considered in the 

feasibility study, please provide to 

OSHA relevant information that 

contains data supporting the 

effectiveness, in reducing exposure to 

crystalline silica, of those substitutes. 

Provide any information you may have 

on the health hazards associated with 

exposure to these substitutes. 

65. Information regarding the 

effectiveness of dust control kits that 

incorporate local exhaust ventilation in 

the railroad transportation industry in 

reducing worker exposure to crystalline 

silica is not available from the 

manufacturer. If you have any relevant 

information on the effectiveness of such 

kits, please provide it to OSHA. 

66. The proposed rule prohibits the 

use of compressed air and dry brushing 

and sweeping for cleaning of surfaces 

and clothing in general industry, 

maritime, and construction and 

promotes the use of wet methods and 

HEPA-filter vacuuming as alternatives. 

Are there any circumstances in general 

industry, maritime, or construction 

work where dry sweeping is the only 

kind of sweeping that can be done? 

Have you done dry sweeping and, if so, 

what has been your experience with it? 

What methods have you used to 

minimize dust when dry sweeping? Can 

exposure levels be kept below the 

proposed PEL when dry sweeping is 

conducted? How? Provide exposure data 

for periods when you conducted dry 

sweeping. If silica respirable dust 

samples are not available, provide real 

time respirable dust or gravimetric 

respirable dust data. Is water available 

at most sites to wet down dust prior to 

sweeping? How effective is the use of 

water? Does the use of water cause other 

problems for the worksite? Are there 

other substitutes that are effective? 

67. A 30-day exemption from the 

requirement to implement engineering 

and work practice controls was not 

included in the proposed standard for 

construction, and has been removed 

from the proposed standard for general 

industry and maritime. OSHA requests 

comment on this issue. 

68. The proposed prohibition on 

employee rotation is explained in the 

Summary and Explanation for 

paragraph (f) Methods of Compliance. 

OSHA solicits comment on the 

prohibition of employee rotation to 

achieve compliance when exposure 

levels exceed the PEL. 

Medical Surveillance 

69. Is medical surveillance being 

provided for respirable crystalline 

silica-exposed employees at your 

worksite? If so: 

a. How do you determine which 

employees receive medical surveillance 

(e.g., by exposure level or other factors)? 

b. Who administers and implements 

the medical surveillance (e.g., company 

doctor or nurse, outside doctor or 

nurse)? 

c. What examinations, tests, or 

evaluations are included in the medical 

surveillance program? Does your 

medical surveillance program include 

testing for latent TB? Do you include 

pulmonary function testing in your 

medical surveillance program? 

d. What benefits (e.g., health, 

reduction in absenteeism, or financial) 

have been achieved from the medical 

surveillance program? 

e. What are the costs of your medical 

surveillance program? How do your 

costs compare with OSHA’s estimated 

unit costs for the physical examination 

and employee time involved in the 

medical surveillance program? Are 

OSHA’s baseline assumptions and cost 

estimates for medical surveillance 

consistent with your experiences 

providing medical surveillance to your 

employees? 

f. How many employees are included 

in your medical surveillance program? 

g. What NAICS code describes your 

workplace? 

70. Is the content and frequency of 

proposed examinations appropriate? If 

not, how should content and frequency 

be modified? 

71. Is the specified content of the 

physician or other licensed health care 

professional’s (PLHCP) written medical 

opinion sufficiently detailed to enable 

the employer to address the employee’s 

needs and potential workplace 

improvements, and yet appropriately 

limited so as to protect the employee’s 

medical privacy? If not, how could the 

medical opinion be improved? 

72. Is the requirement for latent TB 

testing appropriate? Does the proposed 

rule implement this requirement in a 

cost-effective manner? Provide the data 

or cite references that support your 

position. 

73. Is the requirement for pulmonary 

function testing initially and at threeyear intervals appropriate? Is there an 

alternate strategy or schedule for 

conducting follow-up testing that is 

better? Provide data or cite references to 

support your position. 

74. Is the requirement for chest X-rays 

initially and at three-year intervals 

appropriate? Is there an alternate 

strategy or schedule for conducting 

follow-up chest X-rays that you believe 

would be better? Provide data or cite 

references to support your position. 

75. Are there other tests that should 

be included in medical surveillance? 

76. Do you provide medical 

surveillance to employees under 

another OSHA standard or as a matter 

of company policy? If so, describe your 

program in terms of what standards the 

program addresses and such factors as 

content and frequency of examinations 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56291 

and referrals, and reports to the 

employer. 

77. Is exposure for 30 days at or above 

the PEL the appropriate number of days 

to trigger medical surveillance? Should 

the appropriate reference for medical 

monitoring be the PEL or the action 

level? Is 30 days from initial assignment 

a reasonable amount of time to provide 

a medical exam? Indicate the basis for 

your position. 

78. Are PLHCPs available in your 

geographic area to provide medical 

surveillance to workers who are covered 

by the proposed rule? For example, do 

you have access to qualified X-ray 

technicians, NIOSH-certified B-readers, 

and pulmonary specialists? Describe 

any difficulties you may have with 

regard to access to PLHCPs to provide 

surveillance for the rule. Note what you 

consider your ‘‘geographic area’’ in 

responding to this question. 

79. OSHA is proposing to allow an 

‘‘equivalent diagnostic study’’ in place 

of requirements to use a chest X-ray 

(posterior/anterior view; no less than 14 

x 17 inches and no more than 16 x 17 

inches at full inspiration; interpreted 

and classified according to the 

International Labour Organization (ILO) 

International Classification of 

Radiographs of Pneumoconioses by a 

NIOSH-certified ‘‘B’’ reader). Two other 

radiological test methods, computed 

tomography (CT) and high resolution 

computed tomography (HRCT), could be 

considered ‘‘equivalent diagnostic 

studies’’ under paragraph (h)(2)(iii) of 

the proposal. However, the benefits of 

CT or HRCT should be balanced with 

risks, including higher radiation doses. 

Also, standardized methods for 

interpreting and reporting results of CT 

or HRCT are not currently available. The 

Agency requests comment on whether 

CT and HRCT should be considered 

‘‘equivalent diagnostic studies’’ under 

the rule. Provide a rationale and 

evidence to support your position. 

80. OSHA has not included 

requirements for medical removal 

protection (MRP) in the proposed rule, 

because OSHA has made a preliminary 

determination that there are few 

instances where temporary worker 

removal and MRP will be useful. The 

Agency requests comment as to whether 

the respirable crystalline silica rule 

should include provisions for the 

temporary removal and extension of 

MRP benefits to employees with certain 

respirable crystalline silica-related 

health conditions. In particular, what 

medical conditions or findings should 

trigger temporary removal and for what 

maximum amount of time should MRP 

benefits be extended? OSHA also seeks 

information on whether or not MRP is 

currently being used by employers with 

respirable crystalline silica-exposed 

workers, and the costs of such programs. 

Hazard Communication and Training 

81. OSHA has proposed that 

employers provide hazard information 

to employees in accordance with the 

Agency’s Hazard Communication 

standard (29 CFR 1910.1200). 

Compliance with the Hazard 

Communication standard would mean 

that there would be a requirement for a 

warning label for substances that 

contain more than 0.1 percent 

crystalline silica. Should this 

requirement be changed so that warning 

labels would only be required of 

substances more than 1 percent by 

weight of silica? Provide the rationale 

for your position. The Agency also has 

proposed additional training specific to 

work with respirable crystalline silica. 

Should OSHA include these additional 

requirements in the final rule, or are the 

requirements of the Hazard 

Communication standard sufficient? 

82. OSHA is providing an abbreviated 

training section in this proposal as 

compared to ASTM consensus 

standards (see ASTM E 1132–06, 

sections 4.8.1–5). The Hazard 

Communication standard is 

comprehensive and covers most of the 

training requirements traditionally 

included in an OSHA health standard. 

Do you concur with OSHA that 

performance-based training specified in 

the Hazard Communication standard, 

supplemented by the few training 

requirements of this section, is 

sufficient in its scope and depth? Are 

there any other training provisions you 

would add? 

83. The proposed rule does not alter 

the requirements for substances to have 

warning labels, specify wording for 

labels, or otherwise modify the 

provisions of the OSHA’s Hazard 

Communication standard. OSHA invites 

comment on these issues. 

Recordkeeping 

84. OSHA is proposing to require 

recordkeeping for air monitoring data, 

objective data, and medical surveillance 

records. The proposed rule’s 

recordkeeping requirements are 

discussed in the Summary and 

Explanation for paragraph (j) 

Recordkeeping. The Agency seeks 

comment on the utility of these 

recordkeeping requirements as well as 

the costs of making and maintaining 

these records. Provide evidence to 

support your position. 

Dates 

85. OSHA requests comment on the 

time allowed for compliance with the 

provisions of the proposed rule. Is the 

time proposed appropriate, or should 

there be a longer or shorter phase-in of 

requirements? In particular, should 

requirements for engineering controls 

and/or medical surveillance be phased 

in over a longer period of time (e.g., over 

1, 2, 3, or more years)? Should an 

extended phase-in period be provided 

for specific industries (e.g., industries 

where first-year or annualized cost 

impacts are highest), specific sizeclasses of employers (e.g., employers 

with fewer than 20 employees), 

combinations of these factors, or all 

firms covered by the rule? Identify any 

industries, processes, or operations that 

have special needs for additional time, 

the additional time required, and the 

reasons for the request. 

86. OSHA is proposing a two-year 

start-up period to allow laboratories 

time to achieve compliance with the 

proposed requirements, particularly 

with regard to requirements for 

accreditation and round robin testing. 

OSHA also recognizes that requirements 

for monitoring in the proposed rule will 

increase the required capacity for 

analysis of respirable crystalline silica 

samples. Do you think that this start-up 

period is enough time for laboratories to 

achieve compliance with the proposed 

requirements and to develop sufficient 

analytic capacity? If you think that 

additional time is needed, please tell 

OSHA how much additional time is 

required and give your reasons for this 

request. 

Appendices 

87. Some OSHA health standards 

include appendices that address topics 

such as the hazards associated with the 

regulated substance, health screening 

considerations, occupational disease 

questionnaires, and PLHCP obligations. 

In this proposed rule, OSHA has 

included a non-mandatory appendix to 

clarify the medical surveillance 

provisions of the rule. What would be 

the advantages and disadvantages of 

including such an appendix in the final 

rule? If you believe it should be 

included, comment on the 

appropriateness of the information 

included. What additional information, 

if any, should be included in the 

appendix? 

II. Pertinent Legal Authority 

The purpose of the Occupational 

Safety and Health Act, 29 U.S.C. 651 et 

seq. (‘‘the Act’’), is to ‘‘. . . assure so far 

as possible every working man and 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56292 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

2The Mineral Dusts tables that contain the silica 

PELs for construction and shipyards do not clearly 

express PELs for cristobalite and tridymite. 29 CFR 

1926.55; 29 CFR 1915.1000. This lack of textual 

clarity likely results from a transcription error in 

the Code of Federal Regulations. OSHA’s current 

proposal provides the same PEL for quartz, 

cristobalite, and tridymite, in general industry, 

construction, and shipyards. 

woman in the nation safe and healthful 

working conditions and to preserve our 

human resources.’’ 29 U.S.C. 651(b). 

To achieve this goal Congress 

authorized the Secretary of Labor (the 

Secretary) to promulgate and enforce 

occupational safety and health 

standards. 29 U.S.C. 654(b) (requiring 

employers to comply with OSHA 

standards), 655(a) (authorizing summary 

adoption of existing consensus and 

federal standards within two years of 

the Act’s enactment), and 655(b) 

(authorizing promulgation, modification 

or revocation of standards pursuant to 

notice and comment). 

The Act provides that in promulgating 

health standards dealing with toxic 

materials or harmful physical agents, 

such as this proposed standard 

regulating occupational exposure to 

respirable crystalline silica, the 

Secretary, shall set the standard which 

most adequately assures, to the extent 

feasible, on the basis of the best 

available evidence that no employee 

will suffer material impairment of 

health or functional capacity even if 

such employee has regular exposure to 

the hazard dealt with by such standard 

for the period of his working life. 29 

U.S.C. 655(b)(5). 

The Supreme Court has held that 

before the Secretary can promulgate any 

permanent health or safety standard, she 

must make a threshold finding that 

significant risk is present and that such 

risk can be eliminated or lessened by a 

change in practices. Industrial Union 

Dept., AFL–CIO v. American Petroleum 

Institute, 448 U.S. 607, 641–42 (1980) 

(plurality opinion) (‘‘The Benzene 

case’’). Thus, section 6(b)(5) of the Act 

requires health standards to reduce 

significant risk to the extent feasible. Id. 

The Court further observed that what 

constitutes ‘‘significant risk’’ is ‘‘not a 

mathematical straitjacket’’ and must be 

‘‘based largely on policy 

considerations.’’ The Benzene case, 448 

U.S. at 655. The Court gave the example 

that if, 

. . . the odds are one in a billion that a 

person will die from cancer . . . the risk 

clearly could not be considered significant. 

On the other hand, if the odds are one in one 

thousand that regular inhalation of gasoline 

vapors that are 2% benzene will be fatal, a 

reasonable person might well consider the 

risk significant. [Id.] 

OSHA standards must be both 

technologically and economically 

feasible. United Steelworkers v. 

Marshall, 647 F.2d 1189, 1264 (D.C. Cir. 

1980) (‘‘The Lead I case’’). The Supreme 

Court has defined feasibility as ‘‘capable 

of being done.’’ Am. Textile Mfrs. Inst. 

v. Donovan, 452 U.S. 490, 509–510 

(1981) (‘‘The Cotton Dust case’’). The 

courts have further clarified that a 

standard is technologically feasible if 

OSHA proves a reasonable possibility, 

. . . within the limits of the best available 

evidence . . . that the typical firm will be 

able to develop and install engineering and 

work practice controls that can meet the PEL 

in most of its operations. [See The Lead I 

case, 647 F.2d at 1272] 

With respect to economic feasibility, 

the courts have held that a standard is 

feasible if it does not threaten massive 

dislocation to or imperil the existence of 

the industry. Id. at 1265. A court must 

examine the cost of compliance with an 

OSHA standard, 

. . . in relation to the financial health and 

profitability of the industry and the likely 

effect of such costs on unit consumer prices 

. . . [T]he practical question is whether the 

standard threatens the competitive stability 

of an industry, . . . or whether any intraindustry or inter-industry discrimination in 

the standard might wreck such stability or 

lead to undue concentration. [Id. (citing 

Indus. Union Dep’t, AFL–CIO v. Hodgson, 

499 F.2d 467 (D.C. Cir. 1974))] 

The courts have further observed that 

granting companies reasonable time to 

comply with new PELs may enhance 

economic feasibility. The Lead I case at 

1265. While a standard must be 

economically feasible, the Supreme 

Court has held that a cost-benefit 

analysis of health standards is not 

required by the Act because a feasibility 

analysis is required. The Cotton Dust 

case, 453 U.S. at 509. 

Finally, sections 6(b)(7) and 8(c) of 

the Act authorize OSHA to include 

among a standard’s requirements 

labeling, monitoring, medical testing, 

and other information-gathering and 

-transmittal provisions. 29 U.S.C. 

655(b)(7), 657(c). 

III. Events Leading to the Proposed 

Standards 

OSHA’s current standards for 

workplace exposure to respirable 

crystalline silica were adopted in 1971, 

pursuant to section 6(a) of the OSH Act 

(36 FR 10466, May 29, 1971). Section 

6(a) provided that in the first two years 

after the effective date of the Act, OSHA 

had to promulgate ‘‘start-up’’ standards, 

on an expedited basis and without 

public hearing or comment, based on 

national consensus or established 

Federal standards that improved 

employee safety or health. Pursuant to 

that authority, OSHA in 1971 

promulgated approximately 425 

permissible exposure limits (PELs) for 

air contaminants, including silica, 

derived principally from Federal 

standards applicable to government 

contractors under the Walsh-Healey 

Public Contracts Act, 41 U.S.C. 35, and 

the Contract Work Hours and Safety 

Standards Act (commonly known as the 

Construction Safety Act), 40 U.S.C. 333. 

The Walsh-Healey Act and Construction 

Safety Act standards, in turn, had been 

adopted primarily from 

recommendations of the American 

Conference of Governmental Industrial 

Hygienists (ACGIH). 

For general industry (see 29 CFR 

1910.1000, Table Z–3), the PEL for 

crystalline silica in the form of 

respirable quartz is based on two 

alternative formulas: (1) A particlecount formula, PELmppcf = 250/(% quartz 

+ 5); and (2) a mass formula proposed 

by ACGIH in 1968, PEL = (10 mg/m3)/ 

(% quartz + 2). The general industry 

PELs for cristobalite and tridymite are 

one-half of the value calculated from 

either of the above two formulas. For 

construction (29 CFR 1926.55, 

Appendix A) and shipyards (29 CFR 

1915.1000, Table Z), the formula for the 

PEL for crystalline silica in the form of 

quartz (PELmppcf = 250/(% quartz + 5)), 

which requires particle counting, is 

derived from the 1970 ACGIH threshold 

limit value (TLV).2 The formula based 

on particle-counting technology used in 

the general industry, construction, and 

shipyard PELs is now considered 

obsolete. 

In 1974, the National Institute for 

Occupational Safety and Health 

(NIOSH) evaluated crystalline silica as a 

workplace hazard and issued criteria for 

a recommended standard on 

occupational exposure to crystalline 

silica (NIOSH, 1974). NIOSH 

recommended that occupational 

exposure to crystalline silica be 

controlled so that no worker is exposed 

to a time-weighted average (TWA) of 

free (respirable crystalline) silica greater 

than 50 mg/m3 as determined by a fullshift sample for up to a 10-hour 

workday, 40-hour workweek. The 

document also recommended a number 

of ancillary provisions for a standard, 

such as exposure monitoring and 

medical surveillance. 

In December 1974, OSHA published 

an Advanced Notice of Proposed 

Rulemaking (ANPRM) based on the 

recommendations in the NIOSH criteria 

document (39 FR 44771, Dec. 27, 1974). 

In the ANPRM, OSHA solicited ‘‘public 

participation on the issues of whether a 

new standard for crystalline silica 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56293 

should be issued on the basis of the 

[NIOSH] criteria or any other 

information, and, if so, what should be 

the contents of a proposed standard for 

crystalline silica.’’ OSHA also set forth 

the particular issues of concern on 

which comments were requested. The 

Agency did not pursue a final rule for 

crystalline silica at that time. 

As information developed during the 

1980s and 1990s, national and 

international classification 

organizations came to recognize 

crystalline silica as a human carcinogen. 

In June 1986, the International Agency 

for Research on Cancer (IARC) evaluated 

the available evidence regarding 

crystalline silica carcinogenicity and 

concluded that it was ‘‘probably 

carcinogenic to humans’’ (IARC, 1987). 

An IARC working group met again in 

October 1996 to evaluate the complete 

body of research, including research 

that had been conducted since the 

initial 1986 evaluation. IARC concluded 

that ‘‘crystalline silica inhaled in the 

form of quartz or cristobalite from 

occupational sources is carcinogenic to 

humans’’ (IARC, 1997). 

In 1991, in the Sixth Annual Report 

on Carcinogens, the U.S. National 

Toxicology Program (NTP) concluded 

that respirable crystalline silica was 

‘‘reasonably anticipated to be a human 

carcinogen’’ (NTP, 1991). NTP 

reevaluated the available evidence and 

concluded, in the Ninth Report on 

Carcinogens (NTP, 2000), that 

‘‘respirable crystalline silica (RCS), 

primarily quartz dust occurring in 

industrial and occupational settings, is 

known to be a human carcinogen, based 

on sufficient evidence of carcinogenicity 

from studies in humans indicating a 

causal relationship between exposure to 

RCS and increased lung cancer rates in 

workers exposed to crystalline silica 

dust’’ (NTP, 2000). ACGIH listed 

respirable crystalline silica (in the form 

of quartz) as a suspected human 

carcinogen in 2000, while lowering the 

TLV to 0.05 mg/m3 (ACGIH, 2001). 

ACGIH subsequently lowered the TLV 

for crystalline silica to 0.025 mg/m3 in 

2006, which is the current value 

(ACGIH, 2010). 

In 1989, OSHA established 8-hour 

TWA PELs of 0.1 for quartz and 0.05 

mg/m3 for cristobalite and tridymite, as 

part of the Air Contaminants final rule 

for general industry (54 FR 2332, Jan. 

19, 1989). OSHA stated that these limits 

presented no substantial change from 

the Agency’s former formula limits, but 

would simplify sampling procedures. In 

providing comments on the proposed 

rule, NIOSH recommended that 

crystalline silica be considered a 

potential carcinogen. 

In 1992, OSHA, as part of the Air 

Contaminants proposed rule for 

maritime, construction, and agriculture, 

proposed the same PELs as for general 

industry, to make the PELs consistent 

across all the OSHA-regulated sectors 

(57 FR 26002, June 12, 1992). However, 

on July 7 of the same year, the U.S. 

Court of Appeals for the Eleventh 

Circuit vacated the 1989 Air 

Contaminants final rule for general 

industry (Am. Fed’n of Labor and Cong. 

of Indus. Orgs. v. OSHA, 965 F.2d 962 

(1992)), which also mooted the 

proposed rule for maritime, 

construction, and agriculture. The 

Court’s decision to vacate the rule 

forced the Agency to return to the PELs 

adopted in the 1970s. 

In 1994, OSHA launched a process to 

determine which safety and health 

hazards in the U.S. needed most 

attention. A priority planning 

committee included safety and health 

experts from OSHA, NIOSH, and the 

Mine Safety and Health Administration 

(MSHA). The committee reviewed 

available information on occupational 

deaths, injuries, and illnesses and held 

an extensive dialogue with 

representatives of labor, industry, 

professional and academic 

organizations, the States, voluntary 

standards organizations, and the public. 

The National Advisory Committee on 

Occupational Safety and Health and the 

Advisory Committee on Construction 

Safety and Health also made 

recommendations. Rulemaking for 

crystalline silica exposure was one of 

the priorities designated by this process. 

OSHA indicated that crystalline silica 

would be added to the Agency’s 

regulatory agenda as other standards 

were completed and resources became 

available. 

In August 1996, the Agency initiated 

enforcement efforts under a Special 

Emphasis Program (SEP) on crystalline 

silica. The SEP was intended to reduce 

worker silica dust exposures that can 

cause silicosis. It included extensive 

outreach as well as inspections. Among 

the outreach materials available were 

slides presenting information on hazard 

recognition and crystalline silica control 

technology, a video on crystalline silica 

and silicosis, and informational cards 

for workers explaining crystalline silica, 

health effects related to exposure, and 

methods of control. The SEP provided 

guidance for targeting inspections of 

worksites with employees at risk of 

developing silicosis. 

As a follow-up to the SEP, OSHA 

undertook numerous non-regulatory 

actions to address silica exposures. For 

example, in October of 1996, OSHA 

launched a joint silicosis prevention 

effort with MSHA, NIOSH, and the 

American Lung Association (DOL, 

1996). This public education campaign 

involved distribution of materials on 

how to prevent silicosis, including a 

guide for working safely with silica and 

stickers for hard hats to remind workers 

of crystalline silica hazards. Spanish 

language versions of these materials 

were also made available. OSHA and 

MSHA inspectors distributed materials 

at mines, construction sites, and other 

affected workplaces. The joint silicosis 

prevention effort included a National 

Conference to Eliminate Silicosis in 

Washington, DC, in March of 1997, 

which brought together approximately 

650 participants from labor, business, 

government, and the health and safety 

professions to exchange ideas and share 

solutions to reach the goal of 

eliminating silicosis. The conference 

highlighted the best methods of 

eliminating silicosis and included 

problem-solving workshops on how to 

prevent the disease in specific 

industries and job operations; plenary 

sessions with senior government, labor, 

and corporate officials; and 

opportunities to meet with safety and 

health professionals who had 

implemented successful silicosis 

prevention programs. 

In 2003, OSHA examined 

enforcement data for the years between 

1997 and 2002 and identified high rates 

of noncompliance with the OSHA 

respirable crystalline silica PEL, 

particularly in construction. This period 

covers the first five years of the SEP. 

These enforcement data, presented in 

Table 1, indicate that 24 percent of 

silica samples from the construction 

industry and 13 percent from general 

industry were at least three times the 

OSHA PEL. The data indicate that 66 

percent of the silica samples obtained 

during inspections in general industry 

were in compliance with the PEL, while 

only 58 percent of the samples collected 

in construction were in compliance. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56294 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE III–1—RESULTS OF TIME-WEIGHTED AVERAGE (TWA) EXPOSURE RESPIRABLE CRYSTALLINE SILICA SAMPLES FOR

CONSTRUCTION AND GENERAL INDUSTRY

[January 1, 1997–December 31, 2002] 

Exposure (severity relative to the PEL) 

Construction Other than construction 

Number of 

samples Percent Number of samples Percent 

< 1 PEL ............................................................................................................ 424 58 2226 66 

1 × PEL to < 2 × PEL ...................................................................................... 86 12 469 14 

2 × PEL to < 3 × PEL ...................................................................................... 48 6 215 6 

≥ 3 × PEL and higher (3+) ............................................................................... 180 24 453 13 

Total # of samples .................................................................................... 738 3363 

Source: OSHA Integrated Management Information System. 

In an effort to expand the 1996 SEP, 

on January 24, 2008, OSHA 

implemented a National Emphasis 

Program (NEP) to identify and reduce or 

eliminate the health hazards associated 

with occupational exposure to 

crystalline silica (OSHA, 2008). The 

NEP targeted worksites with elevated 

exposures to crystalline silica and 

included new program evaluation 

procedures designed to ensure that the 

goals of the NEP were measured as 

accurately as possible, detailed 

procedures for conducting inspections, 

updated information for selecting sites 

for inspection, development of outreach 

programs by each Regional and Area 

Office emphasizing the formation of 

voluntary partnerships to share 

information, and guidance on 

calculating PELs in construction and 

shipyards. In each OSHA Region, at 

least two percent of inspections every 

year are silica-related inspections. 

Additionally, the silica-related 

inspections are conducted at a range of 

facilities reasonably representing the 

distribution of general industry and 

construction work sites in that region. 

A recent analysis of OSHA 

enforcement data from January 2003 to 

December 2009 (covering the period of 

continued implementation of the SEP 

and the first two years of the NEP) 

shows that considerable noncompliance 

with the PEL continues to occur. These 

enforcement data, presented in Table 2, 

indicate that 14 percent of silica 

samples from the construction industry 

and 19 percent for general industry were 

at least three times the OSHA PEL 

during this period. The data indicate 

that 70 percent of the silica samples 

obtained during inspections in general 

industry were in compliance with the 

PEL, and 75 percent of the samples 

collected in construction were in 

compliance. 

TABLE III–2—RESULTS OF TIME-WEIGHTED AVERAGE (TWA) EXPOSURE RESPIRABLE CRYSTALLINE SILICA SAMPLES FOR

CONSTRUCTION AND GENERAL INDUSTRY

[January 1, 2003–December 31, 2009] 

Exposure (severity relative to the PEL) 

Construction Other than construction 

Number of 

samples Percent Number of samples Percent 

< 1 PEL ............................................................................................................ 548 75 948 70 

1 × PEL to < 2 × PEL ...................................................................................... 49 7 107 8 

2 × PEL to < 3 × PEL ...................................................................................... 32 4 46 3 

≥ 3 × PEL and higher (3+) ............................................................................... 103 14 254 19 

Total # of samples .................................................................................... 732 1355 

Source: OSHA Integrated Management Information System. 

Both industry and worker groups have 

recognized that a comprehensive 

standard is needed to protect workers 

exposed to respirable crystalline silica. 

For example, ASTM (originally known 

as the American Society for Testing and 

Materials) has published recommended 

standards for addressing the hazards of 

crystalline silica, and the Building and 

Construction Trades Department, AFL– 

CIO also has recommended a 

comprehensive program standard. These 

recommended standards include 

provisions for methods of compliance, 

exposure monitoring, training, and 

medical surveillance. The National 

Industrial Sand Association has also 

developed exposure assessment, 

medical surveillance, and training 

guidance products. 

In 1997, OSHA announced in its 

Unified Agenda under Long-Term 

Actions that it planned to publish a 

proposed rule on crystalline silica 

‘‘because the agency has concluded that 

there will be no significant progress in 

the prevention of silica-related diseases 

without the adoption of a full and 

comprehensive silica standard, 

including provisions for product 

substitution, engineering controls, 

training and education, respiratory 

protection and medical screening and 

surveillance. A full standard will 

improve worker protection, ensure 

adequate prevention programs, and 

further reduce silica-related diseases.’’ 

(62 FR 57755, 57758, Oct. 29, 1997). In 

November 1998, OSHA moved 

‘‘Occupational Exposure to Crystalline 

Silica’’ to the pre-rule stage in the 

Regulatory Plan (63 FR 61284, 61303– 

304, Nov. 9, 1998). OSHA held a series 

of stakeholder meetings in 1999 and 

2000 to get input on the rulemaking. 

Stakeholder meetings for all industry 

sectors were held in Washington, 

Chicago, and San Francisco. A separate 

stakeholder meeting for the construction 

sector was held in Atlanta. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56295 

OSHA initiated Small Business 

Regulatory Enforcement Fairness Act 

(SBREFA) proceedings in 2003, seeking 

the advice of small business 

representatives on the proposed rule (68 

FR 30583, 30584, May 27, 2003). The 

SBREFA panel, including 

representatives from OSHA, the Small 

Business Administration (SBA), and the 

Office of Management and Budget 

(OMB), was convened on October 20, 

2003. The panel conferred with small 

entity representatives (SERs) from 

general industry, maritime, and 

construction on November 10 and 12, 

2003, and delivered its final report, 

which included comments from the 

SERs and recommendations to OSHA 

for the proposed rule, to OSHA’s 

Assistant Secretary on December 19, 

2003 (OSHA, 2003). 

Throughout the crystalline silica 

rulemaking process, OSHA has 

presented information to, and has 

consulted with, the Advisory Committee 

on Construction Safety and Health 

(ACCSH) and the Maritime Advisory 

Committee on Occupational Safety and 

Health (MACOSH). In December of 

2009, OSHA representatives met with 

ACCSH to discuss the rulemaking and 

receive their comments and 

recommendations. On December 11, 

ACCSH passed motions supporting the 

concept of Table 1 in the draft proposed 

construction rule and recognizing that 

the controls listed in Table 1 are 

effective. (As discussed with regard to 

paragraph (f) of the proposed rule, Table 

1 presents specified control measures 

for selected construction operations.) 

ACCSH also recommended that OSHA 

maintain the protective clothing 

provision found in the SBREFA panel 

draft regulatory text and restore the 

‘‘competent person’’ requirement and 

responsibilities to the proposed rule. 

Additionally, the group recommended 

that OSHA move forward expeditiously 

with the rulemaking process. 

In January 2010, OSHA completed a 

peer review of the draft Health Effects 

analysis and Preliminary Quantitative 

Risk Assessment following procedures 

set forth by OMB in the Final 

Information Quality Bulletin for Peer 

Review, published on the OMB Web site 

on December 16, 2004 (see 70 FR 2664, 

Jan. 14, 2005). Each peer reviewer 

submitted a written report to OSHA. 

The Agency revised its draft documents 

as appropriate and made the revised 

documents available to the public as 

part of this Notice of Proposed 

Rulemaking. OSHA also made the 

written charge to the peer reviewers, the 

peer reviewers’ names, the peer 

reviewers’ reports, and the Agency’s 

response to the peer reviewers’ reports 

publicly available with publication of 

this proposed rule. OSHA will schedule 

time during the informal rulemaking 

hearing for participants to testify on the 

Health Effects analysis and Preliminary 

Quantitative Risk Assessment in the 

presence of peer reviewers and will 

request the peer reviewers to submit any 

amended final comments they may wish 

to add to the record. The Agency will 

consider amended final comments 

received from the peer reviewers during 

development of a final rule and will 

make them publicly available as part of 

the silica rulemaking record. 

IV. Chemical Properties and Industrial 

Uses 

Silica is a compound composed of the 

elements silicon and oxygen (chemical 

formula SiO2). Silica has a molecular 

weight of 60.08, and exists in crystalline 

and amorphous states, both in the 

natural environment and as produced 

during manufacturing or other 

processes. These substances are odorless 

solids, have no vapor pressure, and 

create non-explosive dusts when 

particles are suspended in air (IARC, 

1997). 

Silica is classified as part of the 

‘‘silicate’’ class of minerals, which 

includes compounds that are composed 

of silicon and oxygen and which may 

also be bonded to metal ions or their 

oxides (Hurlbut, 1966). The basic 

structural units of silicates are silicon 

tetrahedrons (SiO4), pyramidal 

structures with four triangular sides 

where a silicon atom is located in the 

center of the structure and an oxygen 

atom is located at each of the four 

corners. When silica tetrahedrons bond 

exclusively with other silica 

tetrahedrons, each oxygen atom is 

bonded to the silicon atom of its original 

ion, as well as to the silicon atom from 

another silica ion. This results in a ratio 

of one atom of silicon to two atoms of 

oxygen, expressed as SiO2. The siliconoxygen bonds within the tetrahedrons 

use only one-half of each oxygen’s total 

bonding energy. This leaves negatively 

charged oxygen ions available to bond 

with available positively charged ions. 

When they bond with metal and metal 

oxides, commonly of iron, magnesium, 

aluminum, sodium, potassium, and 

calcium, they form the silicate minerals 

commonly found in nature (Bureau of 

Mines, 1992). 

In crystalline silica, the silicon and 

oxygen atoms are arranged in a threedimensional repeating pattern. Silica is 

said to be polymorphic, as different 

forms are created when the silica 

tetrahedrons combine in different 

crystalline structures. The primary 

forms of crystalline silica are quartz, 

cristobalite, and tridymite. In an 

amorphous state, silicon and oxygen 

atoms are present in the same 

proportions but are not organized in a 

repeating pattern. Amorphous silica 

includes natural and manufactured 

glasses (vitreous and fused silica, quartz 

glass), biogenic silica, and opals which 

are amorphous silica hydrates (IARC, 

1997). 

Quartz is the most common form of 

crystalline silica and accounts for 

almost 12% by volume of the earth’s 

crust. Alpha quartz, the quartz form that 

is stable below 573 °C, is the most 

prevalent form of crystalline silica 

found in the workplace. It accounts for 

the overwhelming majority of naturally 

found silica and is present in varying 

amounts in almost every type of 

mineral. Alpha quartz is found in 

igneous, sedimentary, and metamorphic 

rock, and all soils contain at least a trace 

amount of quartz (Bureau of Mines, 

1992). Alpha quartz is used in many 

products throughout various industries 

and is a common component of building 

materials (Madsen et al., 1995). 

Common trade names for commercially 

available quartz include: CSQZ, DQ 12, 

Min-U-Sil, Sil-Co-Sil, Snowit, Sykron 

F300, and Sykron F600 (IARC, 1997). 

Cristobalite is a form of crystalline 

silica that is formed at high 

temperatures (>1470 °C). Although 

naturally occurring cristobalite is 

relatively rare, volcanic eruptions, such 

as Mount St. Helens, can release 

cristobalite dust into the air. Cristobalite 

can also be created during some 

processes conducted in the workplace. 

For example, flux-calcined 

diatomaceous earth is a material used as 

a filtering aid and as a filler in other 

products (IARC, 1997). It is produced 

when diatomaceous earth (diatomite), a 

geological product of decayed 

unicellular organisms called diatoms, is 

heated with flux. The finished product 

can contain between 40 and 60 percent 

cristobalite. Also, high temperature 

furnaces are often lined with bricks that 

contain quartz. When subjected to 

prolonged high temperatures, this 

quartz can convert to cristobalite. 

Tridymite is another material formed 

at high temperatures (>870 °C) that is 

associated with volcanic activity. The 

creation of tridymite requires the 

presence of a flux such as sodium oxide. 

Tridymite is rarely found in nature and 

rarely reported in the workplace (Smith, 

1998). 

When heated or cooled sufficiently, 

crystalline silica can transition between 

the polymorphic forms, with specific 

transitions occurring at different 

temperatures. At higher temperatures 

the linkages between the silica 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56296 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

tetrahedrons break and reform, resulting 

in new crystalline structures. Quartz 

converts to cristobalite at 1470 °C, and 

at 1723 °C cristobalite loses its 

crystalline structure and becomes 

amorphous fused silica. These high 

temperature transitions reverse 

themselves at extremely slow rates, with 

different forms co-existing for a long 

time after the crystal cools. 

Other types of transitions occur at 

lower temperatures when the silicaoxygen bonds in the silica tetrahedron 

rotate or stretch, resulting in a new 

crystalline structure. These lowtemperature, or alpha to beta, transitions 

are readily and rapidly reversed as the 

crystal cools. At temperatures 

encountered by workers, only the alpha 

form of crystalline silica exists (IARC, 

1997). 

Crystalline silica minerals produce 

distinct X-ray diffraction patterns, 

specific to their crystalline structure. 

The patterns can be used to distinguish 

the crystalline polymorphs from each 

other and from amorphous silica (IARC, 

1997). 

The specific gravity and melting point 

of silica vary between polymorphs. 

Silica is insoluble in water at 20 °C and 

in most acids, but its solubility 

increases with higher temperatures and 

pH, and it dissolves readily in 

hydrofluoric acid. Solubility is also 

affected by the presence of trace metals 

and by particle size. Under humid 

conditions water vapor in the air reacts 

with the surface of silica particles to 

form an external layer of silinols (SiOH). 

When these silinols are present the 

crystalline silica becomes more 

hydrophilic. Heating or acid washing 

reduces the amount of silinols on the 

surface area of crystalline silica 

particles. There is an external 

amorphous layer found in aged quartz, 

called the Beilby layer, which is not 

found on freshly cut quartz. This 

amorphous layer is more water soluble 

than the underlying crystalline core. 

Etching with hydrofluoric acid removes 

the Beilby layer as well as the principal 

metal impurities on quartz. 

Crystalline silica has limited chemical 

reactivity. It reacts with alkaline 

aqueous solutions, but does not readily 

react with most acids, with the 

exception of hydrofluoric acid. In 

contrast, amorphous silica and most 

silicates react with most mineral acids 

and alkaline solutions. Analytical 

chemists relied on this difference in 

acid reactivity to develop the silica 

point count analytical method that was 

widely used prior to the current X-ray 

diffraction and infrared methods 

(Madsen et al., 1995). 

Crystalline silica is used in industry 

in a wide variety of applications. Sand 

and gravel are used in road building and 

concrete construction. Sand with greater 

than 98% silica is used in the 

manufacture of glass and ceramics. 

Silica sand is used to form molds for 

metal castings in foundries, and in 

abrasive blasting operations. Silica is 

also used as a filler in plastics, rubber, 

and paint, and as an abrasive in soaps 

and scouring cleansers. Silica sand is 

used to filter impurities from municipal 

water and sewage treatment plants, and 

in hydraulic fracturing for oil and gas 

recovery. Silica is also used to 

manufacture artificial stone products 

used as bathroom and kitchen 

countertops, and the silica content in 

those products can exceed 93 percent 

(Kramer et al., 2012). 

There are over thirty major industries 

and operations where exposures to 

crystalline silica can occur. They 

include such diverse workplaces as 

foundries, dental laboratories, concrete 

products and paint and coating 

manufacture, as well as construction 

activities including masonry cutting, 

grinding and tuckpointing, operating 

heavy equipment, and road work. A 

more detailed discussion of the 

industries affected by the proposed 

standard is presented in Section VIII of 

this preamble. Crystalline silica 

exposures can also occur in mining, and 

in agriculture during plowing and 

harvesting. 

V. Health Effects Summary 

This section presents a summary of 

OSHA’s review of the health effects 

literature for respirable crystalline 

silica. OSHA’s full analysis is contained 

in Section I of the background 

document entitled ‘‘Respirable 

Crystalline Silica—Health Effects 

Literature Review and Preliminary 

Quantitative Risk Assessment,’’ which 

has been placed in rulemaking docket 

OSHA–2010–0034. OSHA’s review of 

the literature on the adverse effects 

associated with exposure to crystalline 

silica covers the following topics: 

(1) Silicosis (including relevant data 

from U.S. disease surveillance efforts); 

(2) Lung cancer and cancer at other 

sites; 

(3) Non-malignant respiratory disease 

(other than silicosis); 

(4) Renal and autoimmune effects; 

and 

(5) Physical factors affecting the 

toxicity of crystalline silica. 

The purpose of the Agency’s scientific 

review is to present OSHA’s preliminary 

findings on the nature of the hazards 

presented by exposure to respirable 

crystalline silica, and to present an 

adequate basis for the quantitative risk 

assessment section to follow. OSHA’s 

review reflects the relevant literature 

identified by the Agency through 

previously published reviews, literature 

searches, and contact with outside 

experts. Most of the evidence that 

describes the health risks associated 

with exposure to silica consists of 

epidemiological studies of worker 

populations; in addition, animal and in 

vitro studies on mode of action and 

molecular toxicology are also described. 

OSHA’s review of the silicosis literature 

focused on a few particular issues, such 

as the factors that affect progression of 

the disease and the relationship 

between the appearance of radiological 

abnormalities indicative of silicosis and 

pulmonary function decline. Exposure 

to respirable crystalline silica is the only 

known cause of silicosis and there are 

literally thousands of research papers 

and case studies describing silicosis 

among working populations. OSHA did 

not review every one of these studies, 

because many of them do not relate to 

the issues that are of interest to OSHA. 

OSHA’s health effects literature 

review addresses exposure only to 

airborne respirable crystalline silica 

since there is no evidence that dermal 

or oral exposure presents a hazard to 

workers. This review is also confined to 

issues related to inhalation of respirable 

dust, which is generally defined as 

particles that are capable of reaching the 

gas-exchange region of the lung (i.e., 

particles less than 10 mm in 

aerodynamic diameter). The available 

studies include populations exposed to 

quartz or cristobalite, the two forms of 

crystalline silica most often encountered 

in the workplace. OSHA was unable to 

identify any relevant epidemiological 

literature concerning a third polymorph, 

tridymite, which is also currently 

regulated by OSHA and included in the 

scope of OSHA’s proposed crystalline 

silica standard. 

OSHA’s approach in this review is 

based on a weight-of-evidence 

approach, in which studies (both 

positive and negative) are evaluated for 

their overall quality, and causal 

inferences are drawn based on a 

determination of whether there is 

substantial evidence that exposure 

increases the risk of a particular effect. 

Factors considered in assessing the 

quality of studies include size of the 

cohort studied and power of the study 

to detect a sufficiently low level of 

disease risk; duration of follow-up of the 

study population; potential for study 

bias (such as selection bias in casecontrol studies or survivor effects in 

cross-sectional studies); and adequacy 

of underlying exposure information for 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56297 

examining exposure-response 

relationships. Studies were deemed 

suitable for inclusion in OSHA’s 

Preliminary Quantitative Risk 

Assessment where there was adequate 

quantitative information on exposure 

and disease risks and the study was 

judged to be sufficiently high quality 

according to the criteria described 

above. The Preliminary Quantitative 

Risk Assessment is included in Section 

II of the background document and is 

summarized in Section VI of this 

preamble. 

A draft health effects review 

document was submitted for external 

scientific peer review in accordance 

with the Office of Management and 

Budget’s ‘‘Final Information Quality 

Bulletin for Peer Review’’ (OMB, 2004). 

A summary of OSHA’s responses to the 

peer reviewers’ comments appears in 

Section III of the background document. 

Since the draft health effects review 

document was submitted for external 

scientific peer review, new studies or 

reviews examining possible associations 

between occupational exposure to 

respirable crystalline silica and lung 

cancer have been published. OSHA’s 

analysis of that new information is 

presented in a supplemental literature 

review and is available in the docket 

(OSHA, 2013). 

A. Silicosis and Disease Progression 

1. Pathology and Diagnosis 

Silicosis is a progressive disease in 

which accumulation of respirable 

crystalline silica particles causes an 

inflammatory reaction in the lung, 

leading to lung damage and scarring, 

and, in some cases, progresses to 

complications resulting in disability and 

death. Three types of silicosis have been 

described: an acute form following 

intense exposure to respirable dust of 

high crystalline silica content for a 

relatively short period (i.e., a few 

months or years); an accelerated form, 

resulting from about 5 to 15 years of 

heavy exposure to respirable dusts of 

high crystalline silica content; and, most 

commonly, a chronic form that typically 

follows less intense exposure of usually 

more than 20 years (Becklake, 1994; 

Balaan and Banks, 1992). In both the 

accelerated and chronic form of the 

disease, lung inflammation leads to the 

formation of excess connective tissue, or 

fibrosis, in the lung. The hallmark of the 

chronic form of silicosis is the silicotic 

islet or nodule, one of the few agentspecific lesions in pathology (Balaan 

and Banks, 1992). As the disease 

progresses, these nodules, or fibrotic 

lesions, increase in density and can 

develop into large fibrotic masses, 

resulting in progressive massive fibrosis 

(PMF). Once established, the fibrotic 

process of chronic silicosis is thought to 

be irreversible (Becklake, 1994), and 

there is no specific treatment for 

silicosis (Davis, 1996; Banks, 2005). 

Unlike chronic silicosis, the acute form 

of the disease almost certainly arises 

from exposures well in excess of current 

OSHA standards and presents a 

different pathological picture, one of 

pulmonary alveolar proteinosis. 

Chronic silicosis is the most 

frequently observed type of silicosis in 

the U.S. today. Affected workers may 

have a dry chronic cough, sputum 

production, shortness of breath, and 

reduced pulmonary function. These 

symptoms result from airway restriction 

and/or obstruction caused by the 

development of fibrotic scarring in the 

alveolar sacs and lower region of the 

lung. The scarring can be detected by 

chest x-ray or computerized tomography 

(CT) when the lesions become large 

enough to appear as visible opacities. 

The result is restriction of lung volumes 

and decreased pulmonary compliance 

with concomitant reduced gas transfer 

(Balaan and Banks, 1992). Early stages 

of chronic silicosis can be referred to as 

either simple or nodular silicosis; later 

stages are referred to as either 

pulmonary massive fibrosis (PMF), 

complicated, or advanced silicosis. 

The clinical diagnosis of silicosis has 

three requisites (Balaan and Banks, 

1992; Banks, 2005). The first is the 

recognition by the physician that 

exposure to crystalline silica adequate 

to cause this disease has occurred. The 

second is the presence of chest 

radiographic abnormalities consistent 

with silicosis. The third is the absence 

of other illnesses that could resemble 

silicosis on chest radiograph, e.g., 

pulmonary fungal infection or miliary 

tuberculosis. To describe the presence 

and severity of silicosis from chest x-ray 

films or digital radiographic images, a 

standardized system exists to classify 

the opacities seen on chest radiographs 

(the International Labor Organization 

(ILO) International Classification of 

Radiographs of the Pneumoconioses 

(ILO, 1980, 2002, 2011; Merchant and 

Schwartz, 1998; NIOSH, 2011). This 

system standardizes the description of 

chest x-ray films or digital radiographic 

images with respect to the size, shape, 

and density of opacities, which together 

indicate the severity and extent of lung 

involvement. The density of opacities 

seen on chest x-ray films or digital 

radiographic images is classified on a 4- 

point major category scale (0, 1, 2, or 3), 

with each major category divided into 

three subcategories, giving a 12-point 

scale between 0/0 and 3/+. (For each 

subcategory, the top number indicates 

the major category that the profusion 

most closely resembles, and the bottom 

number indicates the major category 

that was given secondary 

consideration.) Major category 0 

indicates the absence of visible opacities 

and categories 1 to 3 reflect increasing 

profusion of opacities and a 

concomitant increase in severity of 

disease. Biopsy is not necessary to make 

a diagnosis and a diagnosis does not 

require that chest x-ray films or digital 

radiographic images be rated using the 

ILO system (NIOSH, 2002). In addition, 

an assessment of pulmonary function, 

though not itself necessary to confirm a 

diagnosis of silicosis, is important to 

evaluate whether the individual has 

impaired lung function. 

Although chest x-ray is typically used 

to examine workers exposed to 

respirable crystalline silica for the 

presence of silicosis, it is a fairly 

insensitive tool for detecting lung 

fibrosis (Hnizdo et al., 1993; Craighead 

and Vallyathan, 1980; Rosenman et al., 

1997). To address the low sensitivity of 

chest x-rays for detecting silicosis, 

Hnizdo et al. (1993) recommended that 

radiographs consistent with an ILO 

category of 0/1 or greater be considered 

indicative of silicosis among workers 

exposed to a high concentration of 

silica-containing dust. In like manner, to 

maintain high specificity, chest x-rays 

classified as category 1/0 or 1/1 should 

be considered as a positive diagnosis of 

silicosis. 

Newer imaging technologies with 

both research and clinical applications 

include computed tomography, and 

high resolution tomography. Highresolution computed tomography 

(HRCT) uses thinner image slices and a 

different reconstruction algorithm to 

improve spatial resolution over CT. 

Recent studies of high-resolution 

computerized tomography (HRCT) have 

found HRCT to be superior to chest xray imaging for detecting small opacities 

and for identifying PMF (Sun et al., 

2008; Lopes et al., 2008; Blum et al., 

2008). 

The causal relationship between 

exposure to crystalline silica and 

silicosis has long been accepted in the 

scientific and medical communities. Of 

greater interest to OSHA is the 

quantitative relationship between 

exposure to crystalline silica and 

development of silicosis. A large 

number of cross-sectional and 

retrospective studies have been 

conducted to evaluate this relationship 

(Kreiss and Zhen, 1996; Love et al., 

1999; Ng and Chan, 1994; Rosenman et 

al., 1996; Hughes et al., 1998; Muir et 

al., 1989a, 1989b; Park et al., 2002; Chen 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56298 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

et al., 2001; Hnizdo and Sluis-Cremer, 

1993; Miller et al., 1998; Buchanan et 

al., 2003; Steenland and Brown, 1995b). 

In general, these studies, particularly 

those that included retirees, have found 

a risk of radiological silicosis (usually 

defined as x-ray films classified ILO 

major category 1 or greater) among 

workers exposed near the range of 

cumulative exposure permitted by 

current exposure limits. These studies 

are presented in detail in OSHA’s 

Preliminary Quantitative Risk 

Assessment (Section II of the 

background document and summarized 

in Section VI of this preamble). 

2. Silicosis in the United States 

Unlike most occupational diseases, 

surveillance statistics are available that 

provide information on the prevalence 

of silicosis mortality and morbidity in 

the U.S. The most comprehensive and 

current source of surveillance data in 

the U.S. related to occupational lung 

diseases, including silicosis, is the 

National Institute for Occupational 

Safety and Health (NIOSH) WorkRelated Lung Disease (WoRLD) 

Surveillance System; the WoRLD 

Surveillance Report is compiled from 

the most recent data from the WoRLD 

System (NIOSH, 2008c). National 

statistics on mortality associated with 

occupational lung diseases are also 

compiled in the National Occupational 

Respiratory Mortality System (NORMS, 

available on the Internet at http://

webappa.cdc.gov/ords/norms.html), a 

searchable database administered by 

NIOSH. In addition, NIOSH published a 

recent review of mortality statistics in 

its MMWR Report Silicosis Mortality, 

Prevention, and Control—United States, 

1968–2002 (CDC, 2005). For each of 

these sources, data are compiled from 

death certificates reported to state vital 

statistics offices, which are collected by 

the National Center for Health Statistics 

(NCHS). Data on silicosis morbidity are 

available from only a few states that 

administer occupational disease 

surveillance systems, and from data on 

hospital discharges. OSHA believes that 

the mortality and morbidity statistics 

compiled in these sources and 

summarized below indicate that 

silicosis remains a significant 

occupational health problem in the U.S. 

today. 

From 1968 to 2002, silicosis was 

recorded as an underlying or 

contributing cause of death on 16,305 

death certificates; of these, a total of 

15,944 (98 percent) deaths occurred in 

males (CDC, 2005). From 1968 to 2002, 

the number of silicosis deaths decreased 

from 1,157 (8.91 per million persons 

aged ≥15 years) to 148 (0.66 per 

million), corresponding to a 93-percent 

decline in the overall mortality rate. In 

its most recent WoRLD Report (NIOSH, 

2008c), NIOSH reported that the number 

of silicosis deaths in 2003, 2004, and 

2005 were 179, 166, and 161, 

respectively, slightly higher than that 

reported in 2002. The number of 

silicosis deaths identified each year has 

remained fairly constant since the late 

1990’s. 

NIOSH cited two main factors that 

were likely responsible for the declining 

trend in silicosis mortality since 1968. 

First, many of the deaths in the early 

part of the study period occurred among 

persons whose main exposure to 

crystalline silica dust probably occurred 

before introduction of national 

standards for silica dust exposure 

established by OSHA and the Mine 

Safety and Health Administration 

(MSHA) (i.e., permissible exposure 

limits (PELs)) that likely led to reduced 

silica dust exposure. Second, there has 

been declining employment in heavy 

industries (e.g., foundries) where silica 

exposure was prevalent (CDC, 2005). 

Although the factors described by 

NIOSH are reasonable explanations for 

the steep reduction in silicosis-related 

mortality, it should be emphasized that 

the surveillance data are insufficient for 

the analysis of residual risk associated 

with current occupational exposure 

limits for crystalline silica. Analyses 

designed to explore this question must 

make use of appropriate exposureresponse data, as is presented in 

OSHA’s Preliminary Quantitative Risk 

Assessment (summarized in Section VI 

of this preamble). 

Although the number of deaths from 

silicosis overall has declined since 

1968, the number of silicosis-associated 

deaths reported among persons aged 15 

to 44 had not declined substantially 

prior to 1995 (CDC 1998). 

Unfortunately, it is not known to what 

extent these deaths among younger 

workers were caused by acute or 

accelerated forms of silicosis. 

Silicosis deaths among workers of all 

ages result in significant premature 

mortality; between 1996 and 2005, a 

total of 1,746 deaths resulted in a total 

of 20,234 years of life lost from life 

expectancy, with an average of 11.6 

years of life lost. For the same period, 

among 307 decedents who died before 

age 65, or the end of a working life, 

there were 3,045 years of life lost to age 

65, with an average of 9.9 years of life 

lost from a working life (NIOSH, 2008c). 

Data on the prevalence of silicosis 

morbidity are available from only three 

states (Michigan, Ohio, and New Jersey) 

that have administered disease 

surveillance programs over the past 

several years. These programs rely 

primarily on hospital discharge records, 

reporting of cases from the medical 

community, workers’ compensation 

programs, and death certificate data. For 

the reporting period 1993–2002, the last 

year for which data are available, three 

states (Michigan, New Jersey and Ohio) 

recorded 879 cases of silicosis (NIOSH 

2008c). Hospital discharge records 

represent the primary ascertainment 

source for all three states. It should be 

noted that hospital discharge records 

most likely include cases of acute 

silicosis or very advance chronic 

silicosis since it is unlikely that there 

would be a need for hospitalization in 

cases with early radiographic signs of 

silicosis, such as for an ILO category 

1/0 x-ray. Nationwide hospital 

discharge data compiled by NIOSH 

(2008c) and the Council of State and 

Territorial Epidemiologists (CSTE, 2005) 

indicates that there are at least 1,000 

hospitalizations each year due to 

silicosis. 

Data on silicosis mortality and 

morbidity are likely to understate the 

true impact of exposure of U.S. workers 

to crystalline silica. This is in part due 

to underreporting that is characteristic 

of passive case-based disease 

surveillance systems that rely on the 

health care community to generate 

records (Froines et al., 1989). Health 

care professionals play the main role in 

such surveillance by virtue of their 

unique role in recognizing and 

diagnosing diseases, but most health 

care professionals do not take 

occupational histories (Goldman and 

Peters, 1981; Rutstein et al., 1983). In 

addition to the lack of information about 

exposure histories, difficulty in 

recognizing occupational illnesses that 

have long latency periods, like silicosis, 

contributes to under-recognition and 

underreporting by health care providers. 

Based on an analysis of data from 

Michigan’s silicosis surveillance 

activities, Rosenman et al. (2003) 

estimated that the true incidence of 

silicosis mortality and morbidity were 

understated by a factor of between 2.5 

and 5, and that there were estimated to 

be from 3,600 to 7,300 new cases of 

silicosis occurring in the U.S. annually 

between 1987 and 1996. Taken with the 

surveillance data presented above, 

OSHA believes that exposure to 

crystalline silica remains a cause of 

significant mortality and morbidity in 

the U.S. 

3. Progression of Silicosis and Its 

Associated Impairment 

As described above, silicosis is a 

progressive lung disease that is usually 

first detected by the appearance of a 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56299 

diffuse nodular fibrosis on chest x-ray 

films. To evaluate the clinical 

significance of radiographic signs of 

silicosis, OSHA reviewed several 

studies that have examined how 

exposure affects progression of the 

disease (as seen by chest radiography) as 

well as the relationship between 

radiologic findings and pulmonary 

function. The following summarizes 

OSHA’s preliminary findings from this 

review. 

Of the several studies reviewed by 

OSHA that documented silicosis 

progression in populations of workers, 

four studies (Hughes et al., 1982; Hessel 

et al., 1988; Miller et al., 1998; Ng et al., 

1987a) included quantitative exposure 

data that were based on either current 

or historical measurements of respirable 

quartz. The exposure variable most 

strongly associated in these studies with 

progression of silicosis was cumulative 

respirable quartz (or silica) exposure 

(Hessel et al., 1988; Hughes et al., 1982; 

Miller et al., 1998; Ng et al., 1987a), 

though both average concentration of 

respirable silica (Hughes et al., 1982; Ng 

et al., 1987a) and duration of 

employment in dusty jobs have also 

been found to be associated with the 

progression of silicosis (Hughes et al., 

1982; Ogawa et al., 2003). 

The study reflecting average 

exposures most similar to current 

exposure conditions is that of Miller et 

al. (1998), which followed a group of 

547 British coal miners in 1990–1991 to 

evaluate chest x-ray changes that had 

occurred after the mines closed in 1981. 

This study had data available from chest 

x-rays taken during health surveys 

conducted between 1954 and 1978, as 

well as data from extensive exposure 

monitoring conducted between 1964 

and 1978. The mean and maximum 

cumulative exposure reported in the 

study correspond to average 

concentrations of 0.12 and 0.55 mg/m3, 

respectively, over the 15-year sampling 

period. However, between 1971 and 

1976, workers experienced unusually 

high concentrations of respirable quartz 

in one of the two coal seams in which 

the miners worked. For some 

occupations, quarterly mean quartz 

concentrations ranged from 1 to 3 mg/ 

m3, and for a brief period, 

concentrations exceeded 10 mg/m3 for 

one job. Some of these high exposures 

likely contributed to the extent of 

disease progression seen in these 

workers; in its Preliminary Quantitative 

Risk Assessment, OSHA reviewed a 

study by Buchanan et al. (2003), who 

found that short-term exposures to high 

(>2 mg/m3) concentrations of silica can 

increase the silicosis risk by 3-fold over 

what would be predicted by cumulative 

exposure alone (see Section VI). 

Among the 504 workers whose last 

chest x-ray was classified as ILO 0/0 or 

0/1, 20 percent had experienced onset of 

silicosis (i.e., chest x-ray was classified 

as ILO 1/0 by the time of follow up in 

1990–1991), and 4.8 percent progressed 

to at least category 2. However, there are 

no data available to continue following 

the progression of this group because 

there have been no follow-up surveys of 

this cohort since 1991. 

In three other studies examining the 

progression of silicosis, (Hessel et al., 

1988; Hughes et al., 1982; Ng et al., 

1987a) cohorts were comprised of 

silicotics (individuals already diagnosed 

with silicosis) that were followed 

further to evaluate disease progression. 

These studies reflect exposures of 

workers to generally higher average 

concentrations of respirable quartz than 

are permitted by OSHA’s current 

exposure limit. Some general findings 

from this body of literature follow. First, 

size of opacities on initial radiograph is 

a determinant for further progression. 

Individuals with large opacities on 

initial chest radiograph have a higher 

probability of further disease 

progression than those with small 

opacities (Hughes et al., 1982; Lee, et al., 

2001; Ogawa et al., 2003). Second, 

although silicotics who continue to be 

exposed are more likely to progress than 

silicotics who are not exposed (Hessel et 

al., 1988), once silicosis has been 

detected there remains a likelihood of 

progression in the absence of additional 

exposure to silica (Hessel et al., 1988; 

Miller et al., 1998; Ogawa, et al., 2003; 

Yang et al., 2006). There is some 

evidence in the literature that the 

probability of progression is likely to 

decline over time following the end of 

the exposure, although this observation 

may also reflect a survivor effect 

(Hughes et al., 1982; Lee et al., 2001). In 

addition, of borderline statistical 

significance was the association of 

tuberculosis with increased likelihood 

of silicosis progression (Lee et al., 2001). 

Of the four studies reviewed by OSHA 

that provided quantitative exposure 

information, two studies (Miller et al., 

1998; Ng et al., 1987a) provide the 

information most relevant to current 

exposure conditions. The range of 

average concentration of respirable 

crystalline silica to which workers were 

exposed in these studies (0.12 to 0.48 

mg/m3, respectively) is relatively 

narrow and is of particular interest to 

OSHA because current enforcement data 

indicate that exposures in this range or 

not much lower are common today, 

especially in construction and 

foundries, and sandblasting operations. 

These studies reported the percentage of 

workers whose chest x-rays show signs 

of progression at the time of follow-up; 

the annual rate at which workers 

showed disease progression were 

similar, 2 percent and 6 percent, 

respectively. 

Several cross-sectional and 

longitudinal studies have examined the 

relationship between progressive 

changes observed on radiographs and 

corresponding declines in lung-function 

parameters. In general, the results are 

mixed: some studies have found that 

pulmonary function losses correlate 

with the extent of fibrosis seen on chest 

x-ray films, and others have not found 

such correlations. The lack of a 

correlation in some studies between 

degree of fibrotic profusion seen on 

chest x-rays and pulmonary function 

have led some to suggest that 

pulmonary function loss is an 

independent effect of exposure to 

respirable crystalline silica, or may be a 

consequence of emphysematous 

changes that have been seen in 

conjunction with radiographic silicosis. 

Among studies that have reported 

finding a relationship between 

pulmonary function and x-ray 

abnormalities, Ng and Chan (1992) 

found that forced expiratory volume 

(FEV1) and forced vital capacity (FVC) 

were statistically significantly lower for 

workers whose x-ray films were 

classified as ILO profusion categories 2 

and 3, but not among workers with ILO 

category 1 profusion compared to those 

with a profusion score of 0/0. As 

expected, highly significant reductions 

in FEV1, FVC, and FEV1/FVC were 

noted in subjects with large opacities. 

The authors concluded that chronic 

simple silicosis, except that classified as 

profusion category 1, is associated with 

significant lung function impairment 

attributable to fibrotic disease. 

Similarly, Moore et al. (1988) also 

found chronic silicosis to be associated 

with significant lung function loss, 

especially among workers with chest xrays classified as ILO profusion 

categories 2 and 3. For those classified 

as category 1, lung function was not 

diminished. Be ́gin et al. (1988) also 

found a correlation between decreased 

lung function (FVC and the ratio of 

FEV1/FVC) and increased profusion and 

coalescence of opacities as determined 

by CT scan. This study demonstrated 

increased impairment among workers 

with higher imaging categories (3 and 

4), as expected, but also impairment 

(significantly reduced expiratory flow 

rates) among persons with more 

moderate pulmonary fibrosis (group 2). 

In a population of gold miners, Cowie 

(1998) found that lung function 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56300 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

declined more rapidly in men with 

silicosis than those without. In addition 

to the 24 ml./yr. decrements expected 

due to aging, this study found an 

additional loss of 8 ml. of FEV1 per year 

would be expected from continued 

exposure to dust in the mines. An 

earlier cross-sectional study by these 

authors (Cowie and Mabena, 1991), 

which examined 1,197 black 

underground gold miners who had 

silicosis, found that silicosis (analyzed 

as a continuous variable based on chest 

x-ray film classification) was associated 

with reductions in FVC, FEV1, FEV1/

FVC, and carbon monoxide diffusing 

capacity (DLco), and these relationships 

persisted after controlling for duration 

and intensity of exposure and smoking. 

In contrast to these studies, other 

investigators have reported finding 

pulmonary function decrements in 

exposed workers independent of 

radiological evidence of silicosis. 

Hughes et al. (1982) studied a 

representative sample of 83 silicotic 

sandblasters, 61 of whom were followed 

for one to seven years. A multiple 

regression analysis showed that the 

annual reductions in FVC, FEV1 and 

DLco were related to average silica 

concentrations but not duration of 

exposure, smoking, stage of silicosis, or 

time from initial exposure. Ng et al. 

(1987b) found that, among male 

gemstone workers in Hong Kong with xrays classified as either Category 0 or 1, 

declines in FEV1 and FVC were not 

associated with radiographic category of 

silicosis after adjustment for years of 

employment. The authors concluded 

that there was an independent effect of 

respirable dust exposure on pulmonary 

function. In a population of 61 gold 

miners, Wiles et al. (1992) also found 

that radiographic silicosis was not 

associated with lung function 

decrements. In a re-analysis and followup of an earlier study, Hnizdo (1992) 

found that silicosis was not a significant 

predictor of lung function, except for 

FEV1 for non-smokers. 

Wang et al. (1997) observed that 

silica-exposed workers (both 

nonsmokers and smokers), even those 

without radiographic evidence of 

silicosis, had decreased spirometric 

parameters and diffusing capacity 

(DLco). Pulmonary function was further 

decreased in the presence of silicosis, 

even those with mild to moderate 

disease (ILO categories 1 and 2). The 

authors concluded that functional 

abnormalities precede radiographic 

changes of silicosis. 

A number of studies were conducted 

to examine the role of emphysematous 

changes in the presence of silicosis in 

reducing lung function; these have been 

reviewed by Gamble et al. (2004), who 

concluded that there is little evidence 

that silicosis is related to development 

of emphysema in the absence of PMF. 

In addition, Gamble et al. (2004) found 

that, in general, studies found that the 

lung function of those with radiographic 

silicosis in ILO category 1 was 

indistinguishable from those in category 

0, and that those in category 2 had small 

reductions in lung function relative to 

those with category 0 and little 

difference in the prevalence of 

emphysema. There were slightly greater 

decrements in lung function with 

category 3 and more significant 

reductions with progressive massive 

fibrosis. In studies for which 

information was available on both 

silicosis and emphysema, reduced lung 

function was more strongly related to 

emphysema than to silicosis. 

In conclusion, many studies reported 

finding an association between 

pulmonary function decrements and 

ILO category 2 or 3 background 

profusion of small opacities; this 

appears to be consistent with the 

histopathological view, in which 

individual fibrotic nodules 

conglomerate to form a massive fibrosis 

(Ng and Chan, 1992). Emphysema may 

also play a role in reducing lung 

function in workers with higher grades 

of silicosis. Pulmonary function 

decrements have not been reported in 

some studies among workers with 

silicosis scored as ILO category 1. 

However, a number of other studies 

have documented declines in 

pulmonary function in persons exposed 

to silica and whose radiograph readings 

are in the major ILO category 1 (i.e. 1/ 

0, 1/1, 1/2), or even before changes were 

seen on chest x-ray (Be ́gin et al., 1988; 

Cowie, 1998; Cowie and Mabena, 1991; 

Ng et al., 1987a; Wang et al., 1997). It 

may also be that studies designed to 

relate x-ray findings with pulmonary 

function declines are further 

confounded by pulmonary function 

declines caused by chronic obstructive 

pulmonary disease (COPD) seen among 

silica-exposed workers absent 

radiological silicosis, as has been seen 

in many investigations of COPD. 

OSHA’s review of the literature on 

crystalline silica exposure and 

development of COPD appears in 

section II.D of the background document 

and is summarized in section V.D 

below. 

OSHA believes that the literature 

reviewed above demonstrates decreased 

lung function among workers with 

radiological evidence of silicosis 

consistent with an ILO classification of 

major category 2 or higher. Also, given 

the evidence of functional impairment 

in some workers prior to radiological 

evidence of silicosis, and given the low 

sensitivity of radiography, particularly 

in detecting early silicosis, OSHA 

believes that exposure to silica impairs 

lung function in at least some 

individuals before silicosis can be 

detected on chest radiograph. 

4. Pulmonary Tuberculosis 

As silicosis progresses, it may be 

complicated by severe mycobacterial 

infections, the most common of which 

is pulmonary tuberculosis (TB). Active 

tuberculosis infection is a wellrecognized complication of chronic 

silicosis, and such infections are known 

as silicotuberculosis (IARC, 1997; 

NIOSH, 2002). The risk of developing 

TB infection is higher in silicotics than 

non-silicotics (Balmes, 1990; Cowie, 

1994; Hnizdo and Murray, 1998; 

Kleinschmidt and Churchyard, 1997; 

and Murray et al., 1996). There also is 

evidence that exposure to silica 

increases the risk for pulmonary 

tuberculosis independent of the 

presence of silicosis (Cowie, 1994; 

Hnizdo and Murray, 1998; 

teWaterNaude et al., 2006). In a 

summary of the literature on silicarelated disease mechanisms, Ding et al. 

(2002) noted that it is well documented 

that exposure to silica can lead to 

impaired cell-mediated immunity, 

increasing susceptibility to 

mycobacterial infection. Reduced 

numbers of T-cells, increased numbers 

of B-cells, and alterations of serum 

immunoglobulin levels have been 

observed in workers with silicosis. In 

addition, according to Ng and Chan 

(1991), silicosis and TB act 

synergistically to increase fibrotic scar 

tissue (leading to massive fibrosis) or to 

enhance susceptibility to active 

mycobacterial infection. Lung fibrosis is 

common to both diseases and both 

diseases decrease the ability of alveolar 

macrophages to aid in the clearance of 

dust or infectious particles. 

B. Carcinogenic Effects of Silica (Cancer 

of the Lung and Other Sites) 

OSHA conducted an independent 

review of the epidemiological literature 

on exposure to respirable crystalline 

silica and lung cancer, covering more 

than 30 occupational groups in over a 

dozen industrial sectors. In addition, 

OSHA reviewed a pooled case-control 

study, a large national death certificate 

study, two national cancer registry 

studies, and six meta-analyses. In all, 

OSHA’s review included approximately 

60 primary epidemiological studies. 

Based on its review, OSHA 

preliminarily concludes that the human 

data summarized in this section 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56301 

provides ample evidence that exposure 

to respirable crystalline silica increases 

the risk of lung cancer among workers. 

The strongest evidence comes from the 

worldwide cohort and case-control 

studies reporting excess lung cancer 

mortality among workers exposed to 

respirable crystalline silica dust as 

quartz in various industrial sectors, 

including the granite/stone quarrying 

and processing, industrial sand, mining, 

and pottery and ceramic industries, as 

well as to cristobalite in diatomaceous 

earth and refractory brick industries. 

The 10-cohort pooled case-control 

analysis by Steenland et al. (2001a) 

confirms these findings. A more recent 

clinic-based pooled case-control 

analysis of seven European countries by 

Cassidy et al. (2007) as well as two 

national death certificate registry 

studies (Pukkala et al., 2005 in Finland; 

Calvert et al., 2003 in the United States) 

support the findings from the cohort 

and case-control analysis. 

1. Overall and Industry Sector-Specific 

Findings 

Associations between exposure to 

respirable crystalline silica and lung 

cancer have been reported in worker 

populations from many different 

industrial sectors. IARC (1997) 

concluded that crystalline silica is a 

confirmed human carcinogen based 

largely on nine studies of cohorts in four 

industry sectors that IARC considered to 

be the least influenced by confounding 

factors (sectors included quarries and 

granite works, gold mining, ceramic/

pottery/refractory brick industries, and 

the diatomaceous earth industry). IARC 

(2012) recently reaffirmed that 

crystalline silica is a confirmed human 

carcinogen. NIOSH (2002) also 

determined that crystalline silica is a 

human carcinogen after evaluating 

updated literature. 

OSHA believes that the strongest 

evidence for carcinogenicity comes from 

studies in five industry sectors. These 

are: 

• Diatomaceous Earth Workers 

(Checkoway et al., 1993, 1996, 1997, 

and 1999; Seixas et al., 1997); 

• British Pottery Workers (Cherry et 

al., 1998; McDonald et al., 1995); 

• Vermont Granite Workers (Attfield 

and Costello, 2004; Graham et al., 2004; 

Costello and Graham, 1988; Davis et al., 

1983); 

• North American Industrial Sand 

Workers (Hughes et al., 2001; McDonald 

et al., 2001, 2005; Rando et al., 2001; 

Sanderson et al., 2000; Steenland and 

Sanderson, 2001); and 

• British Coal Mining (Miller et al., 

2007; Miller and MacCalman, 2009). 

The studies above were all 

retrospective cohort or case-control 

studies that demonstrated positive, 

statistically significant exposureresponse relationships between 

exposure to crystalline silica and lung 

cancer mortality. Except for the British 

pottery studies, where exposureresponse trends were noted for average 

exposure only, lung cancer risk was 

found to be related to cumulative 

exposure. OSHA credits these studies 

because in general, they are of sufficient 

size and have adequate years of follow 

up, and have sufficient quantitative 

exposure data to reliably estimate 

exposures of cohort members. As part of 

their analyses, the authors of these 

studies also found positive exposureresponse relationships for silicosis, 

indicating that underlying estimates of 

worker exposures were not likely to be 

substantially misclassified. 

Furthermore, the authors of these 

studies addressed potential confounding 

due to other carcinogenic exposures 

through study design or data analysis. 

A series of studies of the 

diatomaceous earth industry 

(Checkoway et al., 1993, 1996, 1997, 

1999) demonstrated positive exposureresponse trends between cristobalite 

exposures and lung cancer as well as 

non-malignant respiratory disease 

mortality (NMRD). Checkoway et al. 

(1993) developed a ‘‘semi-quantitative’’ 

cumulative exposure estimate that 

demonstrated a statistically significant 

positive exposure-response trend (p = 

0.026) between duration of employment 

or cumulative exposure and lung cancer 

mortality. The quartile analysis showed 

a monotonic increase in lung cancer 

mortality, with the highest exposure 

quartile having a RR of 2.74 for lung 

cancer mortality. Checkoway et al. 

(1996) conducted a re-analysis to 

address criticisms of potential 

confounding due to asbestos and again 

demonstrated a positive exposure 

response risk gradient when controlling 

for asbestos exposure and other 

variables. Rice et al. (2001) conducted a 

re-analysis and quantitative risk 

assessment of the Checkoway et al. 

(1997) study, which OSHA has included 

as part of its assessment of lung cancer 

mortality risk (See Section II, 

Preliminary Quantitative Risk 

Assessment). 

In the British pottery industry, excess 

lung cancer risk was found to be 

associated with crystalline silica 

exposure among workers in a PMR 

study (McDonald et al., 1995) and in a 

cohort and nested case-control study 

(Cherry et al., 1998). In the PMR study, 

elevated PMRs for lung cancer were 

found after adjusting for potential 

confounding by asbestos exposure. In 

the study by Cherry et al., odds ratios 

for lung cancer mortality were 

statistically significantly elevated after 

adjusting for smoking. Odds ratios were 

related to average, but not cumulative, 

exposure to crystalline silica. The 

findings of the British pottery studies 

are supported by other studies within 

their industrial sector. Studies by 

Winter et al. (1990) of British pottery 

workers and by McLaughlin et al. (1992) 

both reported finding suggestive trends 

of increased lung cancer mortality with 

increasing exposure to respirable 

crystalline silica. 

Costello and Graham (1988) and 

Graham et al. (2004) in a follow-up 

study found that Vermont granite 

workers employed prior to 1930 had an 

excess risk of lung cancer, but lung 

cancer mortality among granite workers 

hired after 1940 (post-implementation of 

controls) was not elevated in the 

Costello and Graham (1988) study and 

was only somewhat elevated (not 

statistically significant) in the Graham et 

al. (2004) study. Graham et al. (2004) 

concluded that their results did not 

support a causal relationship between 

granite dust exposure and lung cancer 

mortality. Looking at the same 

population, Attfield and Costello (2004) 

developed a quantitative estimate of 

cumulative exposure (8 exposure 

categories) adapted from a job exposure 

matrix developed by Davis et al. (1983). 

They found a statistically significant 

trend with log-transformed cumulative 

exposure. Lung cancer mortality rose 

reasonably consistently through the first 

seven increasing exposure groups, but 

fell in the highest cumulative exposure 

group. With the highest exposure group 

omitted, a strong positive dose-response 

trend was found for both untransformed 

and log-transformed cumulative 

exposures. Attfield and Costello (2004) 

concluded that exposure to crystalline 

silica in the range of cumulative 

exposures typically experienced by 

contemporarily exposed workers causes 

an increased risk of lung cancer 

mortality. The authors explained that 

the highest exposure group would have 

included the most unreliable exposure 

estimates being reconstructed from 

exposures 20 years prior to study 

initiation when exposure estimation 

was less precise. Also, even though the 

highest exposure group consisted of 

only 15 percent of the study population, 

it had a disproportionate effect on 

dampening the exposure-response 

relationship. 

OSHA believes that the study by 

Attfield and Costello (2004) is of 

superior design in that it was a 

categorical analysis that used 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56302 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

quantitative estimates of exposure and 

evaluated lung cancer mortality rates by 

exposure group. In contrast, the findings 

by Graham et al. (2004) are based on a 

dichotomous comparison of risk among 

high- versus low-exposure groups, 

where date-of-hire before and after 

implementation of ventilation controls 

is used as a surrogate for exposure. 

Consequently, OSHA believes that the 

study by Attfield and Costello is the 

more convincing study, and is one of 

the studies used by OSHA for 

quantitative risk assessment of lung 

cancer mortality due to crystalline silica 

exposure. 

The conclusions of the Vermont 

granite worker study (Attfield and 

Costello, 2004) are supported by the 

findings in studies of workers in the 

U.S. crushed stone industry (Costello et 

al., 1995) and Danish stone industry 

(Gue ́nel et al., 1989a, 1989b). Costello et 

al. (1995) found a non-statistically 

significant increase in lung cancer 

mortality among limestone quarry 

workers and a statistically significant 

increased lung cancer mortality in 

granite quarry workers who worked 20 

years or more since first exposure. 

Gue ́nel et al. (1989b), in a Danish cohort 

study, found statistically significant 

increases in lung cancer incidence 

among skilled stone workers and skilled 

granite stone cutters. A study of Finnish 

granite workers that initially showed 

increasing risk of lung cancer with 

increasing silica exposure, upon 

extended follow-up, did not show an 

association and is therefore considered 

a negative study (Toxichemica, Inc., 

2004). 

Studies of two overlapping cohorts in 

the industrial sand industry (Hughes et 

al., 2001; McDonald et al., 2001, 2005; 

Rando et al., 2001; Sanderson et al., 

2000; Steenland and Sanderson, 2001) 

reported comparable results. These 

studies found a statistically significantly 

increased risk of lung cancer mortality 

with increased cumulative exposure in 

both categorical and continuous 

analyses. McDonald et al. (2001) 

examined a cohort that entered the 

workforce, on average, a decade earlier 

than the cohorts that Steenland and 

Sanderson (2001) examined. The 

McDonald cohort, drawn from eight 

plants, had more years of exposure in 

the industry (19 versus 8.8 years). The 

Steenland and Sanderson (2001) cohort 

worked in 16 plants, 7 of which 

overlapped with the McDonald, et al. 

(2001) cohort. McDonald et al. (2001), 

Hughes et al. (2001), and Rando et al. 

(2001) had access to smoking histories, 

plant records, and exposure 

measurements that allowed for 

historical reconstruction and the 

development of a job exposure matrix. 

Steenland and Sanderson (2001) had 

limited access to plant facilities, less 

detailed historic exposure data, and 

used MSHA enforcement records for 

estimates of recent exposure. These 

studies (Hughes et al., 2001; McDonald 

et al., 2005; Steenland and Sanderson, 

2001) show very similar exposure 

response patterns of increased lung 

cancer mortality with increased 

exposure. OSHA included the 

quantitative exposure-response analysis 

from the Hughes et al. (2001) study in 

its Preliminary Quantitative Risk 

Assessment (Section II). 

Brown and Rushton (2005a, 2005b) 

found no association between risk of 

lung cancer mortality and exposure to 

respirable crystalline silica among 

British industrial sand workers. 

However, the small sample size and 

number of years of follow-up limited the 

statistical power of the analysis. 

Additionally, as Steenland noted in a 

letter review (2005a), the cumulative 

exposures of workers in the Brown and 

Ruston (2005b) study were over 10 

times lower than the cumulative 

exposures experienced by the cohorts in 

the pooled analysis that Steenland et al. 

(2001b) performed. The low exposures 

experienced by this cohort would have 

made detecting a positive association 

with lung cancer mortality even more 

difficult. 

Excess lung cancer mortality was 

reported in a large cohort study of 

British coal miners (Miller et al., 2007; 

Miller and MacCalman, 2009). These 

studies examined the mortality 

experience of 17,800 miners through the 

end of 2005. By that time, the cohort 

had accumulated 516,431 person years 

of observation (an average of 29 years 

per miner), with 10,698 deaths from all 

causes. Overall lung cancer mortality 

was elevated (SMR=115.7, 95% C.I. 

104.8–127.7), and a positive exposureresponse relationship with crystalline 

silica exposure was determined from 

Cox regression after adjusting for 

smoking history. Three of the strengths 

of this study are the detailed timeexposure measurements of both quartz 

and total mine dust, detailed individual 

work histories, and individual smoking 

histories. For lung cancer, analyses 

based on the Cox regression provide 

strong evidence that, for these coal 

miners, quartz exposures were 

associated with increased lung cancer 

risk but that simultaneous exposures to 

coal dust did not cause increased lung 

cancer risk. Because of these strengths, 

OSHA included the quantitative 

analysis from this study in its 

Preliminary Quantitative Risk 

Assessment (Section II). 

Studies of lung cancer mortality in 

metal ore mining populations reflect 

mixed results. Many of these mining 

studies were subject to confounding due 

to exposure to other potential 

carcinogens such as radon and arsenic. 

IARC (1997) noted that in only a few ore 

mining studies was confounding from 

other occupational carcinogens taken 

into account. IARC (1997) also noted 

that, where confounding was absent or 

accounted for in the analysis (gold 

miners in the U.S., tungsten miners in 

China, and zinc and lead miners in 

Sardinia, Italy), an association between 

silica exposure and lung cancer was 

absent. Many of the studies conducted 

since IARC’s (1997) review more 

strongly implicate crystalline silica as a 

human carcinogen. Pelucchi et al. 

(2006), in a meta-analysis of studies 

conducted since IARC’s (1997) review, 

reported statistically significantly 

elevated relative risks of lung cancer 

mortality in underground and surface 

miners in three cohort and four casecontrol studies (See Table I–15). Cassidy 

et al. (2007), in a pooled case-control 

analysis, showed a statistically 

significant increased risk of lung cancer 

mortality among miners (OR = 1.48). 

Cassidy et al. (2007) also demonstrated 

a clear linear trend of increasing odds 

ratios for lung cancer with increasing 

exposures. 

Among workers in Chinese tungsten 

and iron mines, mortality from lung 

cancer was not found to be statistically 

significantly increased (Chen et al., 

1992; McLaughlin et al., 1992). In 

contrast, studies of Chinese tin miners 

found increased lung cancer mortality 

rates and positive exposure-response 

associations with increased silica 

exposure (Chen et al., 1992). 

Unfortunately, in many of these Chinese 

tin mines, there was potential 

confounding from arsenic exposure, 

which was highly correlated with 

exposure to crystalline silica (Chen and 

Chen, 2002; Chen et al., 2006). Two 

other studies (Carta et al. (2001) of 

Sardinian miners and stone quarrymen; 

Finkelstein (1998) primarily of 

Canadian miners) were limited to 

silicotics. The Sardinian study found a 

non-statistically significant association 

between crystalline silica exposure and 

lung cancer mortality but no apparent 

exposure-response trend with silica 

exposure. The authors attributed the 

increased lung cancer to increased 

radon exposure and smoking among 

cases as compared to controls. 

Finkelstein (1998) found a positive 

association between silica exposure and 

lung cancer. 

Gold mining has been extensively 

studied in the United States, South 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56303 

Africa, and Australia in four cohort and 

associated nested case-control studies, 

and in two separate case-control studies 

conducted in South Africa. As with 

metal ore mining, gold mining involves 

exposure to radon and other 

carcinogenic agents, which may 

confound the relationship between 

silica exposure and lung cancer. The 

U.S. gold miner study (Steenland and 

Brown, 1995a) did not find an increased 

risk of lung cancer, while the western 

Australian gold miner study (de Klerk 

and Musk, 1998) showed a SMR of 149 

(95% CI 1.26–1.76) for lung cancer. 

Logistic regression analysis of the 

western Australian case control data 

showed that lung cancer mortality was 

statistically significantly associated with 

log cumulative silica exposure after 

adjusting for smoking and bronchitis. 

After additionally adjusting for silicosis, 

the relative risk remained elevated but 

was no longer statistically significant. 

The authors concluded that their 

findings showed statistically 

significantly increased lung cancer 

mortality in this cohort but that the 

increase in lung cancer mortality was 

restricted to silicotic members of the 

cohort. 

Four studies of gold miners were 

conducted in South Africa. Two case 

control studies (Hessel et al., 1986, 

1990) reported no significant association 

between silica exposure and lung 

cancer, but these two studies may have 

underestimated risk, according to 

Hnizdo and Sluis-Cremer (1991). Two 

cohort studies (Reid and Sluis-Cremer, 

1996; Hnizdo and Sluis-Cremer, 1991) 

and their associated nested case-control 

studies found elevated SMRs and odds 

ratios, respectively, for lung cancer. 

Reid and Sluis-Cremer (1996) attributed 

the increased mortality due to lung 

cancer and other non-malignant 

respiratory diseases to cohort members’ 

lifestyle choices (particularly smoking 

and alcohol consumption). However, 

OSHA notes that the study reported 

finding a positive, though not 

statistically significant, association 

between cumulative crystalline silica 

exposure and lung cancer, as well as 

statistically significant association with 

renal failure, COPD, and other 

respiratory diseases that have been 

implicated with silica exposure. 

In contrast, Hnizdo and Sluis-Cremer 

(1991) found a positive exposureresponse relationship between 

cumulative exposure and lung cancer 

mortality among South African gold 

miners after accounting for smoking. In 

a nested case-control study from the 

same cohort, Hnizdo et al. (1997) found 

a statistically significant increase in 

lung cancer mortality that was 

associated with increased cumulative 

dust exposure and time spent 

underground. Of the studies examining 

silica and lung cancer among South 

African gold miners, these two studies 

were the least likely to have been 

affected by exposure misclassification, 

given their rigorous methodologies and 

exposure measurements. Although not 

conclusive in isolation, OSHA considers 

the mining study results, particularly 

the gold mining and the newer mining 

studies, as supporting evidence of a 

causal relationship between exposure to 

silica and lung cancer risk. 

OSHA has preliminarily determined 

that the results of the studies conducted 

in three industry sectors (foundry, 

silicon carbide, and construction 

sectors) were confounded by the 

presence of exposures to other 

carcinogens. Exposure data from these 

studies were not sufficient to 

distinguish between exposure to silica 

dust and exposure to other occupational 

carcinogens. Thus, elevated rates of lung 

cancer found in these industries could 

not be attributed to silica. IARC 

previously made a similar 

determination in reference to the 

foundry industry. However, with 

respect to the construction industry, 

Cassidy et al. (2007), in a large, 

European community-based casecontrol study, reported finding a clear 

linear trend of increasing odds ratio 

with increasing cumulative exposure to 

crystalline silica (estimated semiquantitatively) after adjusting for 

smoking and exposure to insulation and 

wood dusts. Similar trends were found 

for workers in the manufacturing and 

mining industries as well. This study 

was a very large multi-national study 

that utilized information on smoking 

histories and exposure to silica and 

other occupational carcinogens. OSHA 

believes that this study provides further 

evidence that exposure to crystalline 

silica increases the risk of lung cancer 

mortality and, in particular, in the 

construction industry. 

In addition, a recent analysis of 4.8 

million death certificates from 27 states 

within the U.S. for the years 1982 to 

1995 showed statistically significant 

excesses in lung cancer mortality, 

silicosis mortality, tuberculosis, and 

NMRD among persons with occupations 

involving medium and high exposure to 

respirable crystalline silica (Calvert et 

al., 2003). A national records and death 

certificate study was also conducted in 

Finland by Pukkala et al. (2005), who 

found a statistically significant excess of 

lung cancer incidence among men and 

women with estimated medium and 

heavy exposures. OSHA believes that 

these large national death certificate 

studies and the pooled European 

community-based case-control study are 

strongly supportive of the previously 

reviewed epidemiologic data and 

supports the conclusion that 

occupational exposure to crystalline 

silica is a risk factor for lung cancer 

mortality. 

One of the more compelling studies 

evaluated by OSHA is the pooled 

analysis of 10 occupational cohorts (5 

mines and 5 industrial facilities) 

conducted by Steenland et al. (2001a), 

which demonstrated an overall positive 

exposure-response relationship between 

cumulative exposure to silica and lung 

cancer mortality. These ten cohorts 

included 65,980 workers and 1,072 lung 

cancer deaths, and were selected 

because of the availability of raw data 

on exposure to crystalline silica and 

health outcomes. The investigators used 

a nested case control design and found 

lung cancer risk increased with 

increasing cumulative exposure, log 

cumulative exposure, and average 

exposure. Exposure-response trends 

were similar between mining and nonmining cohorts. From their analysis, the 

authors concluded that ‘‘[d]espite this 

relatively shallow exposure–response 

trend, overall our results tend to support 

the recent conclusion by IARC (1997) 

that inhaled crystalline silica in 

occupational settings is a human 

carcinogen, and suggest that existing 

permissible exposure limits for silica 

need to be lowered (Steenland et al., 

2001a). To evaluate the potential effect 

of random and systematic errors in the 

underlying exposure data from these 10 

cohort studies, Steenland and Bartell 

(Toxichemica, Inc., 2004) conducted a 

series of sensitivity analyses at OSHA’s 

request. OSHA’s Preliminary 

Quantitative Risk Assessment (Section 

II) presents additional information on 

the Steenland et al. (2001a) pooled 

cohort study and the sensitivity analysis 

performed by Steenland and Bartell 

(Toxichemica, Inc., 2004). 

2. Smoking, Silica Exposure, and Lung 

Cancer 

Smoking is known to be a major risk 

factor for lung cancer. However, OSHA 

believes it is unlikely that smoking 

explains the observed exposureresponse trends in the studies described 

above, particularly the retrospective 

cohort or nested case-control studies of 

diatomaceous earth, British pottery, 

Vermont granite, British coal, South 

African gold, and industrial sand 

workers. Also, the positive associations 

between silica exposure and lung cancer 

in multiple studies in multiple sectors 

indicates that exposure to crystalline 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56304 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

silica independently increases the risk 

of lung cancer. 

Studies by Hnizdo et al. (1997), 

McLaughlin et al. (1992), Hughes et al. 

(2001), McDonald et al. (2001, 2005), 

Miller and MacCalman (2009), and 

Cassidy et al. (2007) had detailed 

smoking histories with sufficiently large 

populations and a sufficient number of 

years of follow-up time to quantify the 

interaction between crystalline silica 

exposure and cigarette smoking. In a 

cohort of white South African gold 

miners (Hnizdo and Sluis-Cremer, 1991) 

and in the follow-up nested case-control 

study (Hnizdo et al., 1997) found that 

the combined effect of exposure to 

respirable crystalline silica and smoking 

was greater than additive, suggesting a 

multiplicative effect. This synergy 

appeared to be greatest for miners with 

greater than 35 pack-years of smoking 

and higher cumulative exposure to 

silica. In the Chinese nested casecontrol studies reported by McLaughlin 

et al. (1992), cigarette smoking was 

associated with lung cancer, but control 

for smoking did not influence the 

association between silica and lung 

cancer in the mining and pottery 

cohorts studied. The studies of 

industrial sand workers by Hughes et al. 

(2001) and British coal workers by 

Miller and MacCalman (2009) found 

positive exposure-response trends after 

adjusting for smoking histories, as did 

Cassidy et al. (2007) in their 

community-based case-control study of 

exposed European workers. 

In reference to control of potential 

confounding by cigarette smoking in 

crystalline silica studies, Stayner (2007), 

in an invited journal commentary, 

stated: 

Of particular concern in occupational 

cohort studies is the difficulty in adequately 

controlling for confounding by cigarette 

smoking. Several of the cohort studies that 

adjusted for smoking have demonstrated an 

excess of lung cancer, although the control 

for smoking in many of these studies was less 

than optimal. The results of the article by 

Cassidy et al. presented in this journal appear 

to have been well controlled for smoking and 

other workplace exposures. It is quite 

implausible that residual confounding by 

smoking or other risk factors for lung cancer 

in this or other studies could explain the 

observed excess of lung cancer in the wide 

variety of populations and study designs that 

have been used. Also, it is generally 

considered very unlikely that confounding by 

smoking could explain the positive exposureresponse relationships observed in these 

studies, which largely rely on comparisons 

between workers with similar socioeconomic 

backgrounds. 

Given the findings of investigators 

who have accounted for the impact of 

smoking, the weight of the evidence 

reviewed here implicates respirable 

crystalline silica as an independent risk 

factor for lung cancer mortality. This 

finding is further supported by animal 

studies demonstrating that exposure to 

silica alone can cause lung cancer (e.g., 

Muhle et al., 1995). 

3. Silicosis and Lung Cancer Risk 

In general, studies of workers with 

silicosis, as well as meta-analyses that 

include these studies, have shown that 

workers with radiologic evidence of 

silicosis have higher lung cancer risk 

than those without radiologic 

abnormalities or mixed cohorts. Three 

meta-analyses attempted to look at the 

association of increasing ILO 

radiographic categories of silicosis with 

increasing lung cancer mortality. Two of 

these analyses (Kurihara and Wada, 

2004; Tsuda et al., 1997) showed no 

association with increasing lung cancer 

mortality, while Lacasse et al. (2005) 

demonstrated a positive dose-response 

for lung cancer with increasing ILO 

radiographic category. A number of 

other studies, discussed above, found 

increased lung cancer risk among 

exposed workers absent radiological 

evidence of silicosis (Cassidy et al., 

2007; Checkoway et al., 1999; Cherry et 

al., 1998; Hnizdo et al., 1997; 

McLaughlin et al., 1992). For example, 

the diatomaceous earth study by 

Checkoway et al. (1999) showed a 

statistically significant exposureresponse for lung cancer among nonsilicotics. Checkoway and Franzblau 

(2000), reviewing the international 

literature, found all epidemiological 

studies conducted to that date were 

insufficient to conclusively determine 

the role of silicosis in the etiology of 

lung cancer. OSHA preliminarily 

concludes that the more recent pooled 

and meta-analyses do not provide 

compelling evidence that silicosis is a 

necessary precursor to lung cancer. The 

analyses that do suggest an association 

between silicosis and lung cancer may 

simply reflect that more highly exposed 

individuals are at a higher risk for lung 

cancer. 

Animal and in vitro studies have 

demonstrated that the early steps in the 

proposed mechanistic pathways that 

lead to silicosis and lung cancer seem to 

share some common features. This has 

led some of these researchers to also 

suggest that silicosis is a prerequisite to 

lung cancer. Some have suggested that 

any increased lung cancer risk 

associated with silica may be a 

consequence of the inflammation (and 

concomitant oxidative stress) and 

increased epithelial cell proliferation 

associated with the development of 

silicosis. However, other researchers 

have noted that other key factors and 

proposed mechanisms, such as direct 

damage to DNA by silica, inhibition of 

p53, loss of cell cycle regulation, 

stimulation of growth factors, and 

production of oncogenes, may also be 

involved in carcinogenesis induced by 

silica (see Section II.F of the background 

document for more information on these 

studies). Thus, OSHA preliminarily 

concludes that available animal and in 

vitro studies do not support the 

hypothesis that development of silicosis 

is necessary for silica exposure to cause 

lung cancer. 

4. Relationship Between Silica 

Polymorphs and Lung Cancer Risk 

OSHA’s current PELs for respirable 

crystalline silica reflects a once-held 

belief that cristobalite is more toxic than 

quartz (i.e., the existing general industry 

PEL for cristobalite is one-half the 

general industry PEL for quartz). 

Available evidence indicates that this 

does not appear to be the case with 

respect to the carcinogenicity of 

crystalline silica. A comparison between 

cohorts having principally been exposed 

to cristobalite (the diatomaceous earth 

study and the Italian refractory brick 

study) with other well conducted 

studies of quartz-exposed cohorts 

suggests no difference in the toxicity of 

cristobalite versus quartz. The data 

indicates that the SMRs for lung cancer 

mortality among workers in the 

diatomaceous earth (SMR = 141) and 

refractory brick (SMR=151) cohort 

studies are within the range of the SMR 

point estimates of other cohort studies 

with principally quartz exposures 

(quartz exposure of Vermont granite 

workers yielding an SMR of 117; quartz 

and possible post-firing cristobalite 

exposure of British pottery workers 

yielding an SMR of 129; quartz exposure 

among industrial sand workers yielding 

SMRs of 129, (McDonald et al., 2001) 

and 160 (Steenland and Sanderson, 

2001)). Also, the SMR point estimates 

for the diatomaceous earth and 

refractory brick studies are similar to, 

and fall within the 95 percent 

confidence interval of, the odds ratio 

(OR=1.37, 95% CI 1.14–1.65) of the 

recently conducted multi-center casecontrol study in Europe (Cassidy et al., 

2007). 

OSHA believes that the current 

epidemiological literature provides 

little, if any, support for treating 

cristobalite as presenting a greater lung 

cancer risk than comparable exposure to 

respirable quartz. Furthermore, the 

weight of the available toxicological 

literature no longer supports the 

hypothesis that cristobalite has a higher 

toxicity than quartz, and quantitative 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56305 

estimates of lung cancer risk do not 

suggest that cristobalite is more 

carcinogenic than quartz. (See Section 

I.F of the background document, 

Physical Factors that May Influence 

Toxicity of Crystalline Silica, for a fuller 

discussion of this issue.) OSHA 

preliminary concludes that respirable 

cristobalite and quartz dust have similar 

potencies for increasing lung cancer 

risk. Both IARC (1997) and NIOSH 

(2002) reached similar conclusions. 

5. Cancers of Other Sites 

Respirable crystalline silica exposure 

has also been investigated as a potential 

risk factor for cancer at other sites such 

as the larynx, nasopharynx and the 

digestive system including the 

esophagus and stomach. Although many 

of these studies suggest an association 

between exposure to crystalline silica 

and an excess risk of cancer mortality, 

most are too limited in terms of size, 

study design, or potential for 

confounding to be conclusive. Other 

than for lung cancer, cancer mortality 

studies demonstrating a dose-response 

relationship are quite limited. In their 

silica hazard review, NIOSH (2002) 

concluded that, exclusive of the lung, an 

association has not been established 

between silica exposure and excess 

mortality from cancer at other sites. A 

brief summary of the relevant literature 

is presented below. 

a. Cancer of the Larynx and 

Nasopharynx 

Several studies, including three of the 

better-quality lung cancer studies 

(Checkoway et al., 1997; Davis et al., 

1983; McDonald et al., 2001) suggest an 

association between exposure to 

crystalline silica and increased 

mortality from laryngeal cancer. 

However, the evidence for an 

association is not strong due to the 

small number of cases reported and lack 

of statistical significance of most of the 

findings. 

b. Gastric (Stomach) Cancer 

In their 2002 hazard review of 

respirable crystalline silica, NIOSH 

identified numerous epidemiological 

studies and reported statistically 

significant increases in death rates due 

to gastric or stomach cancer. OSHA 

preliminarily concurs with observations 

made previously by Cocco et al. (1996) 

and the NIOSH (2002) crystalline silica 

hazard review that the vast majority of 

epidemiology studies of silica and 

stomach cancer have not sufficiently 

adjusted for the effects of confounding 

factors or have not been sufficiently 

designed to assess a dose-response 

relationship (e.g., Finkelstein and 

Verma, 2005; Moshammer and 

Neuberger, 2004; Selikoff, 1978, Stern et 

al., 2001). Other studies did not 

demonstrate a statistically significant 

dose-response relationship (e.g., Calvert 

et al., 2003; Tsuda et al., 2001). 

Therefore, OSHA believes the evidence 

is insufficient to conclude that silica is 

a gastric carcinogen. 

c. Esophageal Cancer 

Three well-conducted nested casecontrol studies of Chinese workers 

indicated an increased risk of 

esophageal cancer mortality attributed 

by the study’s authors to respirable 

crystalline silica exposure in refractory 

brick production, boiler repair, and 

foundry workers (Pan et al., 1999; 

Wernli et al., 2006) and caisson 

construction work (Yu et al., 2005). 

Each study demonstrated a doseresponse association with some 

surrogate measure of exposure, but 

confounding due to other occupational 

exposures is possible in all three work 

settings (heavy metal exposure in the 

repair of boilers in steel plants, PAH 

exposure in foundry workers, radon and 

radon daughter exposure in Hong Kong 

caisson workers). Other less wellconstructed studies also indicated 

elevated rates of esophageal cancer 

mortality with silica exposure (Tsuda et 

al., 2001; Xu et al., 1996a). 

In contrast, two large national 

mortality studies in Finland and the 

United States, using qualitatively 

ranked exposure estimates, did not 

show a positive association between 

silica exposure and esophageal cancer 

mortality (Calvert et al., 2003; 

Weiderpass et al., 2003). OSHA 

preliminarily concludes that the 

epidemiological literature is not 

sufficiently robust to attribute increased 

esophageal cancer mortality to exposure 

to respirable crystalline silica. 

d. Other Miscellaneous Cancers 

In 2002, NIOSH conducted a thorough 

literature review of the health effects 

potentially associated with crystalline 

silica exposure including a review of 

lung cancer and other carcinogens. 

NIOSH noted that for workers who may 

have been exposed to crystalline silica, 

there have been infrequent reports of 

statistically significant excesses of 

deaths for other cancers. A summary of 

these cancer studies as cited in NIOSH 

(2002) have been reported in the 

following organ systems (see NIOSH, 

2002 for full bibliographic references): 

salivary gland; liver; bone; pancreatic; 

skin; lymphopoetic or hematopoietic; 

brain; and bladder. 

According to NIOSH (2002), an 

association has not been established 

between these cancers and exposure to 

crystalline silica. OSHA believes that 

these isolated reports of excess cancer 

mortality at these sites are not sufficient 

to draw any inferences about the role of 

silica exposure. The findings have not 

been consistently seen among 

epidemiological studies and there is no 

evidence of an exposure response 

relationship. 

C. Other Nonmalignant Respiratory 

Disease 

In addition to causing silicosis, 

exposure to crystalline silica has been 

associated with increased risks of other 

non-malignant respiratory diseases 

(NMRD), primarily chronic obstructive 

pulmonary disease (COPD). COPD is a 

disease state characterized by airflow 

limitation that is not fully reversible. 

The airflow limitation is usually 

progressive and is associated with an 

abnormal inflammatory response of the 

lungs to noxious particles or gases. In 

patients with COPD, either chronic 

bronchitis or emphysema may be 

present or both conditions may be 

present together. The following presents 

OSHA’s discussion of the literature 

describing the relationships between 

silica exposure and non-malignant 

respiratory disease. 

1. Emphysema 

OSHA has considered a series of 

longitudinal studies of white South 

African gold miners conducted by 

Hnizdo and co-workers. Hnizdo et al. 

(1991) found a significant association 

between emphysema (both panacinar 

and centriacinar) and years of 

employment in a high dust occupation 

(respirable dust was estimated to 

contain 30 percent free silica). There 

was no such association found for nonsmokers, as there were only four nonsmokers with a significant degree of 

emphysema found in the cohort. A 

further study by Hnizdo et al. (1994) 

looked at only life-long non-smoking 

South African gold miners. In this 

population, no significant degree of 

emphysema or association with years of 

exposure or cumulative dust exposure 

was found. However, the degree of 

emphysema was significantly associated 

with the degree of hilar gland nodules, 

which the authors suggested might act 

as a surrogate for exposure to silica. The 

authors concluded that the minimal 

degree of emphysema seen in nonsmoking miners exposed to the 

cumulative dust levels found in this 

study (mean 6.8 mg/m3, SD 2.4, range 

0.5 to 20.2, 30 percent crystalline silica) 

was unlikely to cause meaningful 

impairment of lung function. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56306 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

From the two studies above, Hnizdo 

et al. (1994) concluded that the 

statistically significant association 

between exposure to silica dust and the 

degree of emphysema in smokers 

suggests that tobacco smoking 

potentiates the effect of silica dust. In 

contrast to their previous studies, a later 

study by Hnizdo et al. (2000) of South 

African gold miners found that 

emphysema prevalence was decreased 

in relation to dust exposure. The 

authors suggested that selection bias 

was responsible for this finding. 

The findings of several cross-sectional 

and case-control studies were more 

mixed. Becklake et al. (1987), in an 

unmatched case-control study of white 

South African gold miners, determined 

that a miner who had worked in high 

dust for 20 years had a greater chance 

of getting emphysema than a miner who 

had never worked in high dust. A 

reanalysis of this data (de Beer et al., 

1992) including added-back cases and 

controls (because of possible selection 

bias in the original study), still found an 

increased risk for emphysema, although 

the reported odds ratio was smaller than 

previously reported by Becklake et al. 

(1987). Begin et al. (1995), in a study of 

the prevalence of emphysema in silicaexposed workers with and without 

silicosis, found that silica-exposed 

smokers without silicosis had a higher 

prevalence of emphysema than a group 

of asbestos-exposed workers with 

similar smoking history. In nonsmokers, the prevalence of emphysema 

was much higher in those with silicosis 

than in those without silicosis. A study 

of black underground gold miners found 

that the presence and grade of 

emphysema were statistically 

significantly associated with the 

presence of silicosis but not with years 

of mining (Cowie et al., 1993). 

Several of the above studies (Becklake 

et al., 1987; Begin et al., 1995; Hnizdo 

et al., 1994) found that emphysema can 

occur in silica-exposed workers who do 

not have silicosis and suggest that a 

causal relationship may exist between 

exposure to silica and emphysema. The 

findings of experimental (animal) 

studies that emphysema occurs at lower 

silica doses than does fibrosis in the 

airways or the appearance of early 

silicotic nodules (e.g., Wright et al., 

1988) tend to support the findings in 

human studies that silica-induced 

emphysema can occur absent signs of 

silicosis. 

Others have also concluded that there 

is a relationship between emphysema 

and exposure to crystalline silica. Green 

and Vallyathan (1996) reviewed several 

studies of emphysema in workers 

exposed to silica. The authors stated 

that these studies show an association 

between cumulative dust exposure and 

death from emphysema. IARC (1997) 

has also briefly reviewed studies on 

emphysema in its monograph on 

crystalline silica carcinogenicity and 

concluded that exposure to crystalline 

silica increases the risk of emphysema. 

In their 2002 Hazard Review, NIOSH 

concluded that occupational exposure 

to respirable crystalline silica is 

associated with emphysema but that 

some epidemiologic studies suggested 

that this effect may be less frequent or 

absent in non-smokers. 

Hnizdo and Vallyathan (2003) also 

conducted a review of studies 

addressing COPD due to occupational 

silica exposure and concluded that 

chronic exposure to silica dust at levels 

that do not cause silicosis may cause 

emphysema. 

Based on these findings, OSHA 

preliminarily concludes that exposure 

to respirable crystalline silica or silicacontaining dust can increase the risk of 

emphysema, regardless of whether 

silicosis is present. This appears to be 

clearly the case for smokers. It is less 

clear whether nonsmokers exposed to 

silica would also be at higher risk and 

if so, at what levels of exposure. It is 

also possible that smoking potentiates 

the effect of silica dust in increasing 

emphysema risk. 

2. Chronic Bronchitis 

There were no longitudinal studies 

available designed to investigate the 

relationship between silica exposure 

and bronchitis. However, several crosssectional studies provide useful 

information. Studies are about equally 

divided between those that have 

reported a relationship between silica 

exposure and bronchitis and those that 

have not. Several studies demonstrated 

a qualitative or semiquantitative 

relationship between silica exposure 

and chronic bronchitis. Sluis-Cremer et 

al. (1967) found a significant difference 

between the prevalence of chronic 

bronchitis in dust-exposed and non-dust 

exposed male residents of a South 

African gold mining town who smoked, 

but found no increased prevalence 

among non-smokers. In contrast, a 

different study of South African gold 

miners found that the prevalence of 

chronic bronchitis increased 

significantly with increasing dust 

concentration and cumulative dust 

exposure in smokers, nonsmokers, and 

ex-smokers (Wiles and Faure, 1977). 

Similarly, a study of Western Australia 

gold miners found that the prevalence of 

chronic bronchitis, as indicated by odds 

ratios (controlled for age and smoking), 

was significantly increased in those that 

had worked in the mines for 1 to 9 

years, 10 to 19 years, and more than 20 

years, as compared to lifetime nonminers (Holman et al., 1987). Chronic 

bronchitis was present in 62 percent of 

black South African gold miners and 45 

percent of those who had never smoked 

in a study by Cowie and Mabena (1991). 

The prevalence of what the researchers 

called ‘‘chronic bronchitic symptom 

complex’’ reflected the intensity of dust 

exposure. A higher prevalence of 

respiratory symptoms, independent of 

smoking and age, was also found for 

granite quarry workers in Singapore in 

a high exposure group as compared to 

low exposure and control groups, even 

after excluding those with silicosis from 

the analysis (Ng et al., 1992b). 

Other studies found no relationship 

between silica exposure and the 

prevalence of chronic bronchitis. Irwig 

and Rocks (1978) compared silicotic and 

non-silicotic South African gold miners 

and found no significant difference in 

symptoms of chronic bronchitis. The 

prevalence of symptoms of chronic 

bronchitis were also not found to be 

associated with years of mining, after 

adjusting for smoking, in a population 

of current underground uranium miners 

(Samet et al., 1984). Silica exposure was 

described in the study to be ‘‘on 

occasion’’ above the TLV. It was not 

possible to determine, however, 

whether miners with respiratory 

diseases had left the workforce, making 

the remaining population 

unrepresentative. Hard-rock 

(molybdenum) miners, with 27 and 49 

percent of personal silica samples 

greater than 100 and 55 mg/m3, 

respectively, also showed no increase in 

prevalence of chronic bronchitis in 

association with work in that industry 

(Kreiss et al., 1989). However, the 

authors thought that differential outmigration of symptomatic miners and 

retired miners from the industry and 

town might explain that finding. 

Finally, grinders of agate stones (with 

resulting dust containing 70.4 percent 

silica) in India also had no increase in 

the prevalence of chronic bronchitis 

compared to controls matched by 

socioeconomic status, age and smoking, 

although there was a significantly 

higher prevalence of acute bronchitis in 

female grinders. A significantly higher 

prevalence and increasing trend with 

exposure duration for pneumoconiosis 

in the agate workers indicated that had 

an increased prevalence in chronic 

bronchitis been present, it would have 

been detected (Rastogi et al., 1991). 

However, control workers in this study 

may also have been exposed to silica 

and the study and control workers both 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56307 

had high tuberculosis prevalence, 

possibly masking an association of 

exposure with bronchitis (NIOSH, 

2002). Furthermore, exposure durations 

were very short. 

Thus, some prevalence studies 

supported a finding of increased 

bronchitis in workers exposed to silicacontaining dust, while other studies did 

not support such a finding. However, 

OSHA believes that many of the studies 

that did not find such a relationship 

were likely to be biased towards the 

null. For example, some of the 

molybdenum miners studied by Kreiss 

et al. (1989), particularly retired and 

symptomatic miners, may have left the 

town and the industry before the time 

that the cross-sectional study was 

conducted, resulting in a survivor effect 

that could have interfered with 

detection of a possible association 

between silica exposure and bronchitis. 

This survivor effect may also have been 

operating in the study of uranium 

miners in New Mexico (Samet et al., 

1984). In two of the negative studies, 

members of comparison and control 

groups were also exposed to crystalline 

silica (Irwig and Rocks, 1978; Rastogi et 

al., 1991), creating a potential bias 

toward the null. Additionally, 

tuberculosis in both exposed and 

control groups in the agate worker study 

(Rastogi et al., 1991)) may have masked 

an effect (NIOSH, 2002), and the 

exposure durations were very short. 

Several of the positive studies 

demonstrated a qualitative or semiquantitative relationship between silica 

exposure and chronic bronchitis. 

Others have reviewed relevant studies 

and also concluded that there is a 

relationship between exposure to 

crystalline silica and the development 

of bronchitis. The American Thoracic 

Society (ATS) (1997) published an 

official statement on the adverse effects 

of crystalline silica exposure that 

included a section that discussed 

studies on chronic bronchitis (defined 

by chronic sputum production). 

According to the ATS review, chronic 

bronchitis was found to be common 

among worker groups exposed to dusty 

environments contaminated with silica. 

In support of this conclusion, ATS cited 

studies with what they viewed as 

positive findings of South African 

(Hnizdo et al., 1990) and Australian 

(Holman et al., 1987) gold miners, 

Indonesian granite workers (Ng et al., 

1992b), and Indian agate workers 

(Rastogi et al., 1991). ATS did not 

mention studies with negative findings. 

A review published by NIOSH in 

2002 discussed studies related to silica 

exposure and development of chronic 

bronchitis. NIOSH concluded, based on 

the same studies reviewed by OSHA, 

that occupational exposure to respirable 

crystalline silica is associated with 

bronchitis, but that some epidemiologic 

studies suggested that this effect may be 

less frequent or absent in non-smokers. 

Hnizdo and Vallyathan (2003) also 

reviewed studies addressing COPD due 

to occupational silica exposure and 

concluded that chronic exposure to 

silica dust at levels that do not cause 

silicosis may cause chronic bronchitis. 

They based this conclusion on studies 

that they cited as showing that the 

prevalence of chronic bronchitis 

increases with intensity of exposure. 

The cited studies were also reviewed by 

OSHA (Cowie and Mabena, 1991; 

Holman et al., 1987; Kreiss et al., 1989; 

Sluis-Cremer et al., 1967; Wiles and 

Faure, 1977). 

OSHA preliminarily concludes that 

exposure to respirable crystalline silica 

may cause chronic bronchitis and an 

exposure-response relationship may 

exist. Smokers may be at increased risk 

as compared to non-smokers. Chronic 

bronchitis may occur in silica-exposed 

workers who do not have silicosis. 

3. Pulmonary Function Impairment 

OSHA has reviewed numerous 

studies on the relationship of silica 

exposure to pulmonary function 

impairment as measured by spirometry. 

There were several longitudinal studies 

available. Two groups of researchers 

conducted longitudinal studies of lung 

function impairment in Vermont granite 

workers and reached opposite 

conclusions. Graham et al (1981, 1994) 

examined stone shed workers, who had 

the highest exposures to respirable 

crystalline silica (between 50 and 100 

mg/m3), along with quarry workers 

(presumed to have lower exposure) and 

office workers (expected to have 

negligible exposure). The longitudinal 

losses of FVC and FEV1 were not 

correlated with years employed, did not 

differ among shed, quarry, and office 

workers, and were similar, according to 

the authors, to other blue collar workers 

not exposed to occupational dust. 

Eisen et al. (1983, 1995) found the 

opposite. They looked at lung function 

in two groups of granite workers: 

‘‘survivors’’, who participated in each of 

five annual physical exams, and 

‘‘dropouts’’, who did not participate in 

the final exam. There was a significant 

exposure-response relationship between 

exposure to crystalline silica and FEV1

decline among the dropouts but not 

among the survivors. The dropout group 

had a steeper FEV1 loss, and this was 

true for each smoking category. The 

authors concluded that exposures of 

about 50 ug/m3 produced a measurable 

effect on pulmonary function in the 

dropouts. Eisen et al. (1995) felt that the 

‘‘healthy worker effect’’ was apparent in 

this study and that studies that only 

looked at ‘‘survivors’’ would be less 

likely to see any effect of silica on 

pulmonary function. 

A 12-year follow-up of age- and 

smoking-matched granite crushers and 

referents in Sweden found that over the 

follow-up period, the granite crushers 

had significantly greater decreases in 

FEV1, FEV1/FVC, maximum expiratory 

flow, and FEF50 than the referents 

(Malmberg et al., 1993). A longitudinal 

study of South African gold miners 

conducted by Hnizdo (1992) found that 

cumulative dust exposure was a 

significant predictor of most indices of 

decreases in lung function, including 

FEV1 and FVC. A multiple linear 

regression analysis showed that the 

effects of silica exposure and smoking 

were additive. Another study of South 

African gold miners (Cowie, 1998) also 

found a loss of FEV1 in those without 

silicosis. Finally, a study of U.S. 

automotive foundry workers (Hertzberg 

et al., 2002) found a consistent 

association with increased pulmonary 

function abnormalities and estimated 

measures of cumulative silica exposure 

within 0.1 mg/m3. The Hnizdo (1992), 

Cowie et al. (1993), and Cowie (1998) 

studies of South African gold miners 

and the Malmberg et al. (1993) study of 

Swedish granite workers found very 

similar reductions in FEV1 attributable 

to silica dust exposure. 

A number of prevalence studies have 

described relationships between lung 

function loss and silica exposure or 

exposure measurement surrogates (e.g., 

duration of exposure). These findings 

support those of the longitudinal 

studies. Such results have been found in 

studies of white South African gold 

miners (Hnizdo et al., 1990; Irwig and 

Rocks, 1978), black South African gold 

miners (Cowie and Mabena, 1991), 

Quebec silica-exposed workers (Begin, 

et al., 1995), Singapore rock drilling and 

crushing workers (Ng et al., 1992b), 

Vermont granite shed workers 

(Theriault et al., 1974a, 1974b), 

aggregate quarry workers and coal 

miners in Spain (Montes et al., 2004a, 

2004b), concrete workers in The 

Netherlands (Meijer et al., 2001), 

Chinese refractory brick manufacturing 

workers in an iron-steel plant (Wang et 

al., 1997), Chinese gemstone workers 

(Ng et al., 1987b), hard-rock miners in 

Manitoba, Canada (Manfreda et al., 

1982) and Colorado (Kreiss et al., 1989), 

pottery workers in France (Neukirch et 

al., 1994), potato sorters exposed to 

diatomaceous earth containing 

crystalline silica in The Netherlands 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56308 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

(Jorna et al., 1994), slate workers in 

Norway (Suhr et al., 2003), and men in 

a Norwegian community (Humerfelt et 

al., 1998). Two of these prevalence 

studies also addressed the role of 

smoking in lung function impairment 

associated with silica exposure. In 

contrast to the longitudinal study of 

South African gold miners discussed 

above (Hnizdo, 1992), another study of 

South African gold miners (Hnizdo et 

al., 1990) found that the joint effect of 

dust and tobacco smoking on lung 

function impairment was synergistic, 

rather than additive. Also, Montes et al. 

(2004b) found that the criteria for dusttobacco interactions were satisfied for 

FEV1 decline in a study of Spanish 

aggregate quarry workers. 

One of the longitudinal studies and 

many of the prevalence studies 

discussed above directly addressed the 

question of whether silica-exposed 

workers can develop pulmonary 

function impairment in the absence of 

silicosis. These studies found that 

pulmonary function impairment: (1) 

Can occur in silica-exposed workers in 

the absence of silicosis, (2) was still 

evident when silicosis was controlled 

for in the analysis, and (3) was related 

to the magnitude and duration of silica 

exposure rather than to the presence or 

severity of silicosis. 

Many researchers have concluded that 

a relationship exists between exposure 

to silica and lung function impairment. 

IARC (1997) has briefly reviewed 

studies on airways disease (i.e., chronic 

airflow limitation and obstructive 

impairment of lung function) in its 

monograph on crystalline silica 

carcinogenicity and concluded that 

exposure to crystalline silica causes 

these effects. In its official statement on 

the adverse effects of crystalline silica 

exposure, the American Thoracic 

Society (ATS) (1997) included a section 

on airflow obstruction. The ATS noted 

that, in most of the studies reviewed, 

airflow limitation was associated with 

chronic bronchitis. The review of 

Hnizdo and Vallyathan (2003) also 

addressed COPD due to occupational 

silica exposure. They examined the 

epidemiological evidence for an 

exposure-response relationship for 

airflow obstruction in studies where 

silicosis was present or absent. Hnizdo 

and Vallyathan (2003) concluded that 

chronic exposure to silica dust at levels 

that do not cause silicosis may cause 

airflow obstruction. 

Based on the evidence discussed 

above from a number of longitudinal 

studies and numerous cross-sectional 

studies, OSHA preliminarily concludes 

that there is an exposure-response 

relationship between exposure to 

respirable crystalline silica and the 

development of impaired lung function. 

The effect of tobacco smoking on this 

relationship may be additive or 

synergistic. Also, pulmonary function 

impairment has been shown to occur 

among silica-exposed workers who do 

not show signs of silicosis. 

4. Non-malignant Respiratory Disease 

Mortality 

In this section, OSHA reviews studies 

on NMRD mortality that focused on 

causes of death other than from 

silicosis. Two studies of gold miners, a 

study of diatomaceous earth workers, 

and a case-control analysis of death 

certificate data provide useful 

information. 

Wyndham et al. (1986) found a 

significant excess mortality for chronic 

respiratory diseases in a cohort of white 

South African gold miners. Although 

these data did include silicosis 

mortality, the authors found evidence 

demonstrating that none of the miners 

certified on the death certificate as 

dying from silicosis actually died from 

that disease. Instead, pneumoconiosis 

was always an incidental finding in 

those dying from some other cause, the 

most common of which was chronic 

obstructive lung disease. A case-referent 

analysis found that, although the major 

risk factor for chronic respiratory 

disease was smoking, there was a 

statistically significant additional effect 

of cumulative dust exposure, with the 

relative risk estimated to be 2.48 per ten 

units of 1000 particle years of exposure. 

A synergistic effect of smoking and 

cumulative dust exposure on mortality 

from COPD was found in another study 

of white South African gold miners 

(Hnizdo, 1990). Analysis of various 

combinations of dust exposure and 

smoking found a trend in odds ratios 

that indicated this synergism. There was 

a statistically significant increasing 

trend for dust particle-years and for 

cigarette-years of smoking. For 

cumulative dust exposure, an exposureresponse relationship was found, with 

the analysis estimating that those with 

exposures of 10,000, 17,500, or 20,000 

particle-years of exposure had a 2.5-, 

5.06-, or 6.4-times higher mortality risk 

for COPD, respectively, than those with 

the lowest dust exposure of less than 

5000 particle-years. The authors 

concluded that dust alone would not 

lead to increased COPD mortality but 

that dust and smoking act 

synergistically to cause COPD and were 

thus the main risk factor for death from 

COPD in their study. 

Park et al. (2002) analyzed the 

California diatomaceous earth cohort 

data originally studied by Checkoway et 

al. (1997), consisting of 2,570 

diatomaceous earth workers employed 

for 12 months or more from 1942 to 

1994, to quantify the relationship 

between exposure to cristobalite and 

mortality from chronic lung disease 

other than cancer (LDOC). Diseases in 

this category included pneumoconiosis 

(which included silicosis), chronic 

bronchitis, and emphysema, but 

excluded pneumonia and other 

infectious diseases. Smoking 

information was available for about 50 

percent of the cohort and for 22 of the 

67 LDOC deaths available for analysis, 

permitting Park et al. (2002) to at least 

partially adjust for smoking. Using the 

exposure estimates developed for the 

cohort by Rice et al. (2001) in their 

exposure-response study of lung cancer 

risks, Park et al. (2002) evaluated the 

quantitative exposure-response 

relationship for LDOC mortality and 

found a strong positive relationship 

with exposure to respirable crystalline 

silica. OSHA finds this study 

particularly compelling because of the 

strengths of the study design and 

availability of smoking history data on 

part of the cohort and high-quality 

exposure and job history data; 

consequently, OSHA has included this 

study in its Preliminary Quantitative 

Risk Assessment. 

In a case-control analysis of death 

certificate data drawn from 27 U.S. 

states, Calvert et al. (2003) found 

increased mortality odds ratios among 

those in the medium and higher 

crystalline silica exposure categories, a 

significant trend of increased risk for 

COPD mortality with increasing silica 

exposures, and a significantly increased 

odds ratio for COPD mortality in 

silicotics as compared to those without 

silicosis. 

Green and Vallyathan (1996) also 

reviewed several studies of NMRD 

mortality in workers exposed to silica. 

The authors stated that these studies 

showed an association between 

cumulative dust exposure and death 

from the chronic respiratory diseases. 

Based on the evidence presented in 

the studies above, OSHA preliminarily 

concludes that respirable crystalline 

silica increases the risk for mortality 

from non-malignant respiratory disease 

(not including silicosis) in an exposurerelated manner. However, it appears 

that the risk is strongly influenced by 

smoking, and the effects of smoking and 

silica exposure may be synergistic. 

D. Renal and Autoimmune Effects 

In recent years, evidence has 

accumulated that suggests an 

association between exposure to 

crystalline silica and an increased risk 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56309 

of renal disease. Over the past 10 years, 

epidemiologic studies have been 

conducted that provide evidence of 

exposure-response trends to support 

this association. There is also suggestive 

evidence that silica can increase the risk 

of rheumatoid arthritis and other 

autoimmune diseases (Steenland, 

2005b). In fact, an autoimmune 

mechanism has been postulated for 

some silica-associated renal disease 

(Calvert et al., 1997). This section will 

discuss the evidence supporting an 

association of silica exposure with renal 

and autoimmune diseases. 

Overall, there is substantial evidence 

suggesting an association between 

exposure to crystalline silica and 

increased risks of renal and 

autoimmune diseases. In addition to a 

number of case reports, epidemiologic 

studies have found statistically 

significant associations between 

occupational exposure to silica dust and 

chronic renal disease (e.g., Calvert et al., 

1997), subclinical renal changes (e.g., 

Ng et al., 1992c), end-stage renal disease 

morbidity (e.g., Steenland et al., 1990), 

chronic renal disease mortality 

(Steenland et al., 2001b, 2002a), and 

Wegener’s granulomatosis (Nuyts et al., 

1995). In other findings, silica-exposed 

individuals, both with and without 

silicosis, had an increased prevalence of 

abnormal renal function (Hotz et al., 

1995), and renal effects have been 

reported to persist after cessation of 

silica exposure (Ng et al., 1992c). 

Possible mechanisms suggested for 

silica-induced renal disease include a 

direct toxic effect on the kidney, 

deposition in the kidney of immune 

complexes (IgA) following silica-related 

pulmonary inflammation, or an 

autoimmune mechanism (Calvert et al., 

1997; Gregorini et al., 1993). 

Several studies of exposed worker 

populations reported finding excess 

renal disease mortality and morbidity. 

Wyndham et al. (1986) reported finding 

excess mortality from acute and chronic 

nephritis among South African 

goldminers that had been followed for 9 

years. Italian ceramic workers 

experienced an overall increase in the 

prevalence of end-stage renal disease 

(ESRD) cases compared to regional rates; 

the six cases that occurred among the 

workers had cumulative exposures to 

crystalline silica of between 0.2 and 3.8 

mg/m3-years (Rapiti et al., 1999). 

Calvert et al. (1997) found an 

increased incidence of non-systemic 

ESRD cases among 2,412 South Dakota 

gold miners exposed to a median 

crystalline silica concentration of 0.09 

mg/m3. In another study of South 

Dakota gold miners, Steenland and 

Brown (1995a) reported a positive trend 

of chronic renal disease mortality risk 

and cumulative exposure to respirable 

crystalline silica, but most of the excess 

deaths were concentrated among 

workers hired before 1930 when 

exposures were likely higher than in 

more recent years. 

Excess renal disease mortality has 

also been described among North 

American industrial sand workers. 

McDonald et al., (2001, 2005) found that 

nephritis/nephrosis mortality was 

elevated overall among 2,670 industrial 

sand workers hired 20 or more years 

prior to follow-up, but there was no 

apparent relationship with either 

cumulative or average exposure to 

crystalline silica. However, Steenland et 

al. (2001b) did find that increased 

mortality from acute and chronic renal 

disease was related to increasing 

quartiles of cumulative exposure among 

a larger cohort of 4,626 industrial sand 

workers. In addition, they also found a 

positive trend for ESRD case incidence 

and quartiles of cumulative exposure. 

In a pooled cohort analysis, Steenland 

et al. (2002a) combined the industrial 

sand cohort from Steenland et al. 

(2001b), gold mining cohort from 

Steenland and Brown (1995a), and the 

Vermont granite cohort studies by 

Costello and Graham (1988). In all, the 

combined cohort consisted of 13,382 

workers with exposure information 

available for 12,783. The exposure 

estimates were validated by the 

monotonically increasing exposureresponse trends seen in analyses of 

silicosis, since cumulative silica levels 

are known to predict silicosis risk. The 

mean duration of exposure, cumulative 

exposure, and concentration of 

respirable silica for the cohort were 13.6 

years, 1.2 mg/m3-years, and 0.07 mg/m3, 

respectively. 

The analysis demonstrated 

statistically significant exposureresponse trends for acute and chronic 

renal disease mortality with quartiles of 

cumulative exposure to respirable 

crystalline silica. In a nested casecontrol study design, a positive 

exposure-response relationship was 

found across the three cohorts for both 

multiple-cause mortality (i.e., any 

mention of renal disease on the death 

certificate) and underlying cause 

mortality. Renal disease risk was most 

prevalent among workers with 

cumulative exposures of 0.5 mg/m3 or 

more (Steenland et al., 2002a). 

Other studies failed to find an excess 

renal disease risk among silica-exposed 

workers. Davis et al. (1983) found an 

elevated, but not a statistically 

significant increase, in mortality from 

diseases of the genitourinary system 

among Vermont granite shed workers. 

There was no observed relationship 

between mortality from this cause and 

cumulative exposure. A similar finding 

was reported by Koskela et al. (1987) 

among Finnish granite workers, where 

there were 4 deaths due to urinary tract 

disease compared to 1.8 expected. Both 

Carta et al. (1994) and Cocco et al. 

(1994) reported finding no increased 

mortality from urinary tract disease 

among workers in an Italian lead mine 

and a zinc mine. However, Cocco et al. 

(1994) commented that exposures to 

respirable crystalline silica were low, 

averaging 0.007 and 0.09 mg/m3 in the 

two mines, respectively, and that their 

study in particular had low statistical 

power to detect excess mortality. 

There are many case series, casecontrol, and cohort studies that provide 

support for a causal relationship 

between exposure to respirable 

crystalline silica and an increased renal 

disease risk (Kolev et al., 1970; Osorio 

et al., 1987; Steenland et al., 1990; 

Gregorini et al., 1993; Nuyts et al., 

1995). In addition, a number of studies 

have demonstrated early clinical signs 

of renal dysfunction (i.e., urinary 

excretion of low- and high-molecular 

weight proteins and other markers of 

renal glomerular and tubular disruption) 

in workers exposed to crystalline silica, 

both with and without silicosis (Ng et 

al., 1992c; Hotz et al., 1995; Boujemaa, 

1994; Rosenman et al., 2000). 

OSHA believes that there is 

substantial evidence on which to base a 

finding that exposure to respirable 

crystalline silica increases the risk of 

renal disease mortality and morbidity. 

In particular, OSHA believes that the 3- 

cohort pooled analysis conducted by 

Steenland et al. (2002a) is particularly 

convincing. OSHA believes that the 

findings of this pooled analysis seem 

credible because the analysis involved a 

large number of workers from three 

cohorts with well-documented, 

validated job-exposure matrices and 

found a positive and monotonic 

increase in renal disease risk with 

increasing exposure for both underlying 

and multiple cause data. However, there 

are considerably less data, and thus the 

findings based on them are less robust, 

than what is available for silicosis 

mortality or lung cancer mortality. 

Nevertheless, OSHA preliminarily 

concludes that the underlying data are 

sufficient to provide useful estimates of 

risk and has included the Steenland et 

al. (2002a) analysis in its Preliminary 

Quantitative Risk Assessment. 

Several studies of different designs, 

including case series, cohort, registry 

linkage and case-control, conducted in a 

variety of exposed groups suggest an 

association between silica exposure and 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56310 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

increased risk of systemic autoimmune 

disease (Parks et al., 1999). Studies have 

found that the most common 

autoimmune diseases associated with 

silica exposure are scleroderma (e.g., 

Sluis-Cremer et al., 1985); rheumatoid 

arthritis (e.g. Klockars et al., 1987; 

Rosenman and Zhu, 1995); and systemic 

lupus erythematosus (e.g., Brown et al., 

1997). Mechanisms suggested for silicarelated autoimmune disease include an 

adjuvant effect of silica (Parks et al., 

1999), activation of the immune system 

by the fibrogenic proteins and growth 

factors released as a result of the 

interaction of silica particles with 

macrophages (e.g., Haustein and 

Anderegg, 1998), and a direct local 

effect of non-respirable silica particles 

penetrating the skin and producing 

scleroderma (Green and Vallyathan, 

1996). However, there are no 

quantitative exposure-response data 

available at this time on which to base 

a quantitative risk assessment for 

autoimmune diseases. 

Therefore, OSHA preliminarily 

concludes that there is substantial 

evidence that silica exposure increases 

the risks of renal and autoimmune 

disease. The positive and monotonic 

exposure-response trends demonstrated 

for silica exposure and renal disease risk 

more strongly suggest a causal link. The 

studies by Steenland et al. (2001b, 

2002a) and Steenland and Brown 

(1995a) provide evidence of a positive 

exposure-response relationship. For 

autoimmune diseases, the available data 

did not provide an adequate basis for 

assessing exposure-response 

relationships. However, OSHA believes 

that the available exposure-response 

data on silica exposure and renal 

disease is sufficient to allow for 

quantitative estimates of risk. 

E. Physical Factors That May Influence 

Toxicity of Crystalline Silica 

Much research has been conducted to 

investigate the influence of various 

physical factors on the toxicologic 

potency of crystalline silica. Such 

factors examined include crystal 

polymorphism; the age of fractured 

surfaces of the crystal particle; the 

presence of impurities, particularly 

metals, on particle surfaces; and clay 

occlusion of the particle. These factors 

likely vary among different workplace 

settings suggesting that the risk to 

workers exposed to a given level of 

respirable crystalline silica may not be 

equivalent in different work 

environments. In this section, OSHA 

examines the research demonstrating 

the effects of these factors on the 

toxicologic potency of silica. 

The modification of surface 

characteristics by the physical factors 

noted above may alter the toxicity of 

silica by affecting the physical and 

biochemical pathways of the 

mechanistic process. Thus, OSHA has 

reviewed the proposed mechanisms by 

which silica exposure leads to silicosis 

and lung cancer. It has been proposed 

that silicosis results from a cycle of cell 

damage, oxidant generation, 

inflammation, scarring and fibrosis. A 

silica particle entering the lung can 

cause lung damage by two major 

mechanisms: direct damage to lung cells 

due to the silica particle’s unique 

surface properties or by the activation or 

stimulation of alveolar macrophages 

(after phagocytosis) and/or alveolar 

epithelial cells. In either case, an 

elevated production of reactive oxygen 

and nitrogen species (ROS/RNS) results 

in oxidant damage to lung cells. The 

oxidative stress and lung injury 

stimulates alveolar macrophages and/or 

alveolar epithelial cells to produce 

growth factors and fibrogenic mediators, 

resulting in fibroblast activation and 

pulmonary fibrosis. A continuous 

ingestion-reingestion cycle, with cell 

activation and death, is established. 

OSHA has examined evidence on the 

comparative toxicity of the silica 

polymorphs (quartz, cristobalite, and 

tridymite). A number of animal studies 

appear to suggest that cristobalite and 

tridymite are more toxic to the lung than 

quartz and more tumorigenic (e.g., King 

et al., 1953; Wagner et al., 1980). 

However, in contrast to these findings, 

several authors have reviewed the 

studies done in this area and concluded 

that cristobalite and tridymite are not 

more toxic than quartz (e.g., Bolsaitis 

and Wallace, 1996; Guthrie and Heaney, 

1995). Furthermore, a difference in 

toxicity between cristobalite and quartz 

has not been observed in epidemiologic 

studies (tridymite has not been studied) 

(NIOSH, 2002). In an analysis of 

exposure-response for lung cancer, 

Steenland et al. (2001a) found similar 

exposure-response trends between 

cristobalite-exposed workers and other 

cohorts exposed to quartz. 

A number of studies have compared 

the toxicity of freshly fractured versus 

aged silica. Although animal studies 

have demonstrated that freshly fractured 

silica is more toxic than aged silica, 

aged silica still retains significant 

toxicity (Porter et al., 2002; Shoemaker 

et al., 1995; Vallyathan et al., 1995). 

Studies of workers exposed to freshly 

fractured silica have demonstrated that 

these workers exhibit the same cellular 

effects as seen in animals exposed to 

freshly fractured silica (Castranova et 

al., 1998; Goodman et al., 1992). There 

have been no studies, however, 

comparing workers exposed to freshly 

fractured silica to those exposed to aged 

silica. Animal studies also suggest that 

pulmonary reactions of rats to shortduration exposure to freshly fractured 

silica mimic those seen in acute silicosis 

in humans (Vallyathan et al., 1995). 

Surface impurities, particularly 

metals, have been shown to alter silica 

toxicity. Iron, depending on its state and 

quantity, has been shown to either 

increase or decrease toxicity. Aluminum 

has been shown to decrease toxicity 

(Castranova et al., 1997; Donaldson and 

Borm, 1998; Fubini, 1998). Silica coated 

with aluminosilicate clay exhibits lower 

toxicity, possibly as a result of reduced 

bioavailability of the silica particle 

surface (Donaldson and Borm, 1998; 

Fubini, 1998). This reduced 

bioavailability may be due to aluminum 

ions left on the silica surface by the clay 

(Bruch et al., 2004; Cakmak et al., 2004; 

Fubini et al., 2004). Aluminum and 

other metal ions are thought to modify 

silanol groups on the silica surface, thus 

decreasing the membranolytic and 

cytotoxic potency and resulting in 

enhanced particle clearance from the 

lung before damage can take place 

(Fubini, 1998). An epidemiologic study 

found that the risk of silicosis was less 

in pottery workers than in tin and 

tungsten miners (Chen et al., 2005; 

Harrison et al., 2005), possibly reflecting 

that pottery workers were exposed to 

silica particles having less biologically 

available, non-clay-occluded surface 

area than was the case for miners. The 

authors concluded that clay occlusion of 

silica particles can be a factor in 

reducing disease risk. 

Although it is evident that a number 

of factors can act to mediate the 

toxicological potency of crystalline 

silica, it is not clear how such 

considerations should be taken into 

account to evaluate lung cancer and 

silicosis risks to exposed workers. After 

evaluating many in vitro studies that 

had been conducted to investigate the 

surface characteristics of crystalline 

silica particles and their influence on 

fibrogenic activity, NIOSH (2002) 

concluded that further research is 

needed to associate specific surface 

characteristics that can affect toxicity 

with specific occupational exposure 

situations and consequent health risks 

to workers. According to NIOSH (2002), 

such exposures may include work 

processes that produce freshly fractured 

silica surfaces or that involve quartz 

contaminated with trace elements such 

as iron. NIOSH called for further in vitro 

and in vivo studies of the toxicity and 

pathogenicity of alpha quartz compared 

with its polymorphs, quartz 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56311 

contaminated with trace elements, and 

further research on the association of 

surface properties with specific work 

practices and health effects. 

In discussing the ‘‘considerable’’ 

heterogeneity shown across the 10 

studies used in the pooled lung cancer 

risk analysis, Steenland et al. (2001a) 

pointed to hypotheses that physical 

differences in silica exposure (e.g., 

freshness of particle cleavage) between 

cohorts may be a partial explanation of 

observed differences in exposureresponse coefficients derived from those 

cohort studies. However, the authors 

did not have specific information on 

whether or how these factors might have 

actually influenced the observed 

differences. Similarly, in the pooled 

analysis and risk assessments for 

silicosis mortality conducted by 

Mannetje et al. (2002b), differences in 

biological activity of different types of 

silica dust could not be specifically 

taken into account. Mannetje et al. 

(2002b) determined that the exposureresponse relationship between silicosis 

and log-transformed cumulative 

exposure to crystalline silica was 

comparable between studies and no 

significant heterogeneity was found. 

The authors therefore concluded that 

their findings were relevant for different 

circumstances of occupational exposure 

to crystalline silica. Both the Steenland 

et al. (2001a) and Mannetje et al. (2002b) 

studies are discussed in detail in 

OSHA’s Preliminary Quantitative Risk 

Assessment (section II of the 

background document and summarized 

in section VI of this preamble). 

OSHA preliminarily concludes that 

there is considerable evidence to 

support the hypothesis that surface 

activity of crystalline silica particles 

plays an important role in producing 

disease, and that several environmental 

influences can modify surface activity to 

either enhance or diminish the toxicity 

of silica. However, OSHA believes that 

the available information is insufficient 

to determine in any quantitative way 

how these influences may affect disease 

risk to workers in any particular 

workplace setting. 

VI. Summary of OSHA’s Preliminary 

Quantitative Risk Assessment 

A. Introduction 

The Occupational Safety and Health 

Act (OSH Act or Act) and some 

landmark court cases have led OSHA to 

rely on quantitative risk assessment, to 

the extent possible, to support the risk 

determinations required to set a 

permissible exposure limit (PEL) for a 

toxic substance in standards under the 

OSH Act. A determining factor in the 

decision to perform a quantitative risk 

assessment is the availability of suitable 

data for such an assessment. In the case 

of crystalline silica, there has been 

extensive research on its health effects, 

and several quantitative risk 

assessments have been published in the 

peer-reviewed scientific literature that 

describe the risk to exposed workers of 

lung cancer mortality, silicosis mortality 

and morbidity, non-malignant 

respiratory disease mortality, and renal 

disease mortality. These assessments 

were based on several studies of 

occupational cohorts in a variety of 

industry sectors, the underlying studies 

of which are described in OSHA’s 

review of the health effects literature 

(see section V of this preamble). In this 

section, OSHA summarizes its 

Preliminary Quantitative Risk 

Assessment (QRA) for crystalline silica, 

which is presented in Section II of the 

background document entitled 

‘‘Respirable Crystalline Silica—Health 

Effects Literature Review and 

Preliminary Quantitative Risk 

Assessment’’ (placed in Docket OSHA– 

2010–0034). 

OSHA has done what it believes to be 

a comprehensive review of the literature 

to provide quantitative estimates of risk 

for crystalline silica-related diseases. 

Quantitative risk assessments for lung 

cancer and silicosis mortality were 

published after the International Agency 

for Research on Cancer (IARC) 

determined more than a decade ago that 

there was sufficient evidence to regard 

crystalline silica as a human carcinogen 

(IARC, 1997). This finding was based on 

several studies of worker cohorts 

demonstrating associations between 

exposure to crystalline silica and an 

increased risk of lung cancer. Although 

IARC judged the overall evidence as 

being sufficient to support this 

conclusion, IARC also noted that some 

studies of crystalline silica-exposed 

workers did not demonstrate an excess 

risk of lung cancer and that exposureresponse trends were not always 

consistent among studies that were able 

to describe such trends. These findings 

led Steenland et al. (2001a) and 

Mannetje et al. (2002b) to conduct 

comprehensive exposure-response 

analyses of the risk of lung cancer and 

silicosis mortality associated with 

exposure to crystalline silica. These 

studies, referred to as the IARC multicenter studies of lung cancer and 

silicosis mortality, relied on all 

available cohort data from previously 

published epidemiological studies for 

which there were adequate quantitative 

data on worker exposures to crystalline 

silica to derive pooled estimates of 

disease risk. In addition, OSHA 

identified four single-cohort studies of 

lung cancer mortality that it judged 

suitable for quantitative risk assessment; 

two of these cohorts (Attfield and 

Costello, 2004; Rice et al., 2001) were 

included among the 10 used in the IARC 

multi-center study and studies of two 

other cohorts appeared later (Hughes et 

al., 2001; McDonald et al., 2001, 2005; 

Miller and MacCalman, 2009). For nonmalignant respiratory disease mortality, 

in addition to the silicosis mortality 

study by Mannetje et al. (2002b), Park et 

al. (2002) conducted an exposureresponse analysis of non-malignant 

respiratory disease mortality (including 

silicosis and other chronic obstructive 

pulmonary diseases) among 

diatomaceous earth workers. Exposureresponse analyses for silicosis morbidity 

have been published in several singlecohort studies (Chen et al., 2005; 

Hnizdo and Sluis-Cremer, 1993; 

Steenland and Brown, 1995b; Miller et 

al., 1998; Buchanan et al., 2003). 

Finally, a quantitative assessment of 

end-stage renal disease mortality based 

on data from three worker cohorts was 

developed by Steenland et al. (2002a). 

In addition to these published studies, 

OSHA’s contractor, Toxichemica, Inc., 

commissioned Drs. Kyle Steenland and 

Scott Bartell of Emory University to 

perform an uncertainty analysis to 

examine the effect on lung cancer and 

silicosis mortality risk estimates of 

uncertainties that exist in the exposure 

assessments underlying the two IARC 

multi-center analyses (Toxichemica, 

Inc., 2004). 

OSHA’s Preliminary QRA presents 

estimates of the risk of silica-related 

diseases assuming exposure over a 

working life (45 years) to the proposed 

8-hour time-weighted average (TWA) 

PEL and action level of 0.05 and 0.025 

mg/m3, respectively, of respirable 

crystalline silica, as well as to OSHA’s 

current PELs. OSHA’s current general 

industry PEL for respirable quartz is 

expressed both in terms of a particle 

count formula and a gravimetric 

concentration formula, while the 

current construction and shipyard 

employment PELs for respirable quartz 

are only expressed in terms of a particle 

count formula. The current PELs limit 

exposure to respirable dust; the specific 

limit in any given instance depends on 

the concentration of crystalline silica in 

the dust. For quartz, the gravimetric 

general industry PEL approaches a limit 

of 0.1 mg/m3 as respirable quartz as the 

quartz content increases (see discussion 

in Section XVI of this preamble, 

Summary and Explanation for 

paragraph (c)). OSHA’s Preliminary 

QRA presents risk estimates for 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56312 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

exposure over a working lifetime to 0.1 

mg/m3 to represent the risk associated 

with exposure to the current general 

industry PEL. OSHA’s current PEL for 

construction and shipyard employment 

is a formula PEL that limits exposure to 

respirable dust expressed as a respirable 

particle count concentration. As with 

the gravimetric general industry PEL, 

the limit varies depending on quartz 

content of the dust. There is no single 

mass concentration equivalent for the 

construction and shipyard PELs; 

OSHA’s Preliminary QRA reviews 

several studies that suggest that the 

current construction/shipyard PEL 

likely lies in the range between 0.25 and 

0.5 mg/m3 respirable quartz, and OSHA 

presents risk estimates for this range of 

exposure to represent the risks 

associated with exposure to the current 

construction/shipyard PEL. In general 

industry, for both the gravimetric and 

particle count PELs, OSHA’s current 

PEL for cristobalite and tridymite are 

half the value for quartz. Thus, OSHA’s 

Preliminary QRA presents risk estimates 

associated with exposure over a working 

lifetime to 0.025, 0.05, 0.1, 0.25, and 0.5 

mg/m3 respirable silica (corresponding 

to cumulative exposures over 45 years 

to 1.125, 2.25, 4.5, 11.25, and 22.5 mg/ 

m3-years). 

Risk estimates for lung cancer 

mortality, silicosis and non-malignant 

respiratory disease mortality, and renal 

disease mortality are presented in terms 

of lifetime (up to age 85) excess risk per 

1,000 workers for exposure over an 8- 

hour working day, 250 days per year, 

and a 45-year working life. For silicosis 

morbidity, OSHA based its risk 

estimates on cumulative risk models 

used by the various investigators to 

develop quantitative exposure-response 

relationships. These models 

characterized the risk of developing 

silicosis (as detected by chest 

radiography) up to the time that cohort 

members (including both active and 

retired workers) were last examined. 

Thus, risk estimates derived from these 

studies represent less-than-lifetime risks 

of developing radiographic silicosis. 

OSHA did not attempt to estimate 

lifetime risk (i.e., up to age 85) for 

silicosis morbidity because the 

relationships between age, time, and 

disease onset post-exposure have not 

been well characterized. 

A draft preliminary quantitative risk 

assessment document was submitted for 

external scientific peer review in 

accordance with the Office of 

Management and Budget’s ‘‘Final 

Information Quality Bulletin for Peer 

Review’’ (OMB, 2004). A summary of 

OSHA’s responses to the peer reviewers’ 

comments appears in Section III of the 

background document. 

In the sections below, OSHA 

describes the studies and the published 

risk assessments it uses to estimate the 

occupational risk of crystalline silicarelated disease. (The Preliminary QRA 

itself also discusses several other 

available studies that OSHA does not 

include and OSHA’s reasons for not 

including these studies.) 

B. Lung Cancer Mortality 

1. Summary of Studies 

In its Preliminary QRA, OSHA 

discusses risk assessments from six 

published studies that quantitatively 

analyzed exposure-response 

relationships for crystalline silica and 

lung cancer; some of these also provided 

estimates of risks associated with 

exposure to OSHA’s current PEL or 

NIOSH’s Recommended Exposure Limit 

(REL) of 0.05 mg/m3. These studies 

include: (1) A quantitative analysis by 

Steenland et al. (2001a) of worker cohort 

data pooled from ten studies; (2) an 

exposure-response analysis by Rice et 

al. (2001) of a cohort of diatomaceous 

earth workers primarily exposed to 

cristobalite; (3) an analysis by Attfield 

and Costello (2004) of U.S. granite 

workers; (4) a risk assessment by 

Kuempel et al. (2001), who employed a 

kinetic rat lung model to describe the 

relationship between quartz lung 

burden and cancer risk, then calibrated 

and validated that model using the 

diatomaceous earth worker and granite 

worker cohort mortality data; (5) an 

exposure-response analysis by Hughes 

et al., (2001) of U.S. industrial sand 

workers; and (6) a risk analysis by 

Miller et al. (2007) and Miller and 

MacCalman (2009) of British coal 

miners. These six studies are described 

briefly below and are followed by a 

summary of the lung cancer risk 

estimates derived from these studies. 

a. Steenland et al. (2001a) Pooled Cohort 

Analysis 

OSHA considers the lung cancer 

analysis conducted by Steenland et al. 

(2001a) to be of prime importance for 

risk estimation because of its size, 

incorporation of data from multiple 

cohorts, and availability of detailed 

exposure and job history data. 

Subsequent to its publication, Steenland 

and Bartell (Toxichemica, Inc., 2004) 

conducted a quantitative uncertainty 

analysis on the pooled data set to 

evaluate the potential impact on the risk 

estimates of random and systematic 

exposure misclassification, and 

Steenland (personal communication, 

2010) conducted additional exposureresponse modeling. 

The original study consisted of a 

pooled exposure-response analysis and 

risk assessment based on raw data 

obtained from ten cohorts of silicaexposed workers (65,980 workers, 1,072 

lung cancer deaths). Steenland et al. 

(2001a) initially identified 13 cohort 

studies as containing exposure 

information sufficient to develop a 

quantitative exposure assessment; the 

10 studies included in the pooled 

analysis were those for which data on 

exposure and health outcome could be 

obtained for individual workers. The 

cohorts in the pooled analysis included 

U.S. gold miners (Steenland and Brown, 

1995a), U.S. diatomaceous earth 

workers (Checkoway et al., 1997), 

Australian gold miners (de Klerk and 

Musk, 1998), Finnish granite workers 

(Koskela et al., 1994), U.S. industrial 

sand employees (Steenland and 

Sanderson, 2001), Vermont granite 

workers (Costello and Graham, 1988), 

South African gold miners (Hnizdo and 

Sluis-Cremer, 1991; Hnizdo et al., 1997), 

and Chinese pottery workers, tin 

miners, and tungsten miners (Chen et 

al., 1992). 

The exposure assessments developed 

for the pooled analysis are described by 

Mannetje et al. (2002a). The exposure 

information and measurement methods 

used to assess exposure from each of the 

10 cohort studies varied by cohort and 

by time and included dust 

measurements representing particle 

counts, mass of total dust, and 

respirable dust mass. All exposure 

information was converted to units of 

mg/m3 respirable crystalline silica by 

generating cohort-specific conversion 

factors based on the silica content of the 

dust to which workers were exposed. 

A case-control study design was 

employed for which cases and controls 

were matched for race, sex, age (within 

5 years) and study; 100 controls were 

matched to each case. To test the 

reasonableness of the cumulative 

exposure estimates for cohort members, 

Mannetje et al. (2002a) examined 

exposure-response relationships for 

silicosis mortality by performing a 

nested case-control analysis for silicosis 

or unspecified pneumoconiosis using 

conditional logistic regression. Each 

cohort was stratified into quartiles by 

cumulative exposure, and standardized 

rate ratios (SRR) for silicosis were 

calculated using the lowest-exposure 

quartile as the baseline. Odds ratios 

(OR) for silicosis were also calculated 

for the pooled data set overall, which 

was stratified into quintiles based on 

cumulative exposure. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56313 

For the pooled data set, the 

relationship between odds ratio for 

silicosis mortality and increasing 

cumulative exposure was ‘‘positive and 

reasonably monotonic’’, ranging from 

3.1 for the lowest quartile of exposure 

to 4.8 for the highest. In addition, in 

seven of the ten individual cohorts, 

there were statistically significant trends 

between silicosis mortality rate ratios 

(SRR) and cumulative exposure. For two 

of the cohorts (U.S. granite workers and 

U.S. gold miners), the trend test was not 

statistically significant (p=0.10). A trend 

analysis could not be performed on the 

South African gold miner cohort since 

silicosis was not coded as an underlying 

cause of death in that country. A more 

rigorous analysis of silicosis mortality 

on pooled data from six of these cohorts 

also showed a strong, statistically 

significant increasing trend with 

increasing decile of cumulative 

exposure (Mannetje et al., 2002b), 

providing additional evidence for the 

reasonableness of the exposure 

assessment used for the Steenland et al 

(2001a) lung cancer analysis. 

For the pooled lung cancer mortality 

analysis, Steenland et al. (2001a) 

conducted a nested case-control 

analysis via Cox regression, in which 

there were 100 controls chosen for each 

case randomly selected from among 

cohort members who survived past the 

age at which the case died, and matched 

on age (the time variable in Cox 

regression), study, race/ethnicity, sex, 

and date of birth within 5 years (which, 

in effect, matched on calendar time 

given the matching on age). Using 

alternative continuous exposure 

variables in a log-linear relative risk 

model (log RR=bx, where x represents 

the exposure variable and b the 

coefficient to be estimated), Steenland et 

al. (2001a) found that the use of either 

1) cumulative exposure with a 15-year 

lag, 2) the log of cumulative exposure 

with a 15-year lag, or 3) average 

exposure resulted in positive 

statistically significant (p≤0.05) 

exposure-response coefficients. The 

models that provided the best fit to the 

data were those that used cumulative 

exposure and log-transformed 

cumulative exposure. The fit of the loglinear model with average exposure was 

clearly inferior to those using 

cumulative and log-cumulative 

exposure metrics. 

There was significant heterogeneity 

among studies (cohorts) using either 

cumulative exposure or average 

exposure. The authors suggested a 

number of possible reasons for such 

heterogeneity, including errors in 

measurement of high exposures (which 

tends to have strong influence on the 

exposure-response curve when 

untransformed exposure measures are 

used), the differential toxicity of silica 

depending on the crystalline 

polymorph, the presence of coatings or 

trace minerals that alter the reactivity of 

the crystal surfaces, and the age of the 

fractured surfaces. Models that used the 

log transform of cumulative exposure 

showed no statistically significant 

heterogeneity among cohorts (p=0.36), 

possibly because they are less 

influenced by very high exposures than 

models using untransformed cumulative 

exposure. For this reason, as well as the 

good fit of the model using logcumulative exposure, Steenland et al. 

(2001a) conducted much of their 

analysis using log-transformed 

cumulative exposure. The sensitivity 

analysis by Toxichemica, Inc. (2004) 

repeated this analysis after correcting 

some errors in the original coding of the 

data set. At OSHA’s request, Steenland 

(2010) also conducted a categorical 

analysis of the pooled data set and 

additional analyses using linear relative 

risk models (with and without logtransformation of cumulative exposure) 

as well as a 2-piece spline model. 

The cohort studies included in the 

pooled analysis relied in part on particle 

count data and the use of conversion 

factors to estimate exposures of workers 

to mass respirable quartz. A few studies 

were able to include at least some 

respirable mass sampling data. OSHA 

believes that uncertainty in the 

exposure assessments that underlie each 

of the 10 studies included in the pooled 

analysis is likely to represent one of the 

most important sources of uncertainty 

in the risk estimates. To evaluate the 

potential impact of uncertainties in the 

underlying exposure assessments on 

estimates of the risk, OSHA’s contractor, 

Toxichemica, Inc. (2004), commissioned 

Drs. Kyle Steenland and Scott Bartell of 

Emory University to conduct an 

uncertainty analysis using the raw data 

from the pooled cancer risk assessment. 

The uncertainty analysis employed a 

Monte Carlo technique in which two 

kinds of random exposure measurement 

error were considered; these were (1) 

random variation in respirable dust 

measurements and (2) random error in 

estimating respirable quartz exposures 

from historical data on particle count 

concentration, total dust mass 

concentration, and respirable dust mass 

concentration measurements. Based on 

the results of this uncertainty analysis, 

OSHA does not have reason to believe 

that random error in the underlying 

exposure estimates in the Steenland et 

al. (2001a) pooled cohort study of lung 

cancer is likely to have substantially 

influenced the original findings, 

although a few individual cohorts 

(particularly the South African and 

Australian gold miner cohorts) appeared 

to be sensitive to measurement errors. 

The sensitivity analysis also 

examined the potential effect of 

systematic bias in the use of conversion 

factors to estimate respirable crystalline 

silica exposures from historical data. 

Absent a priori reasons to suspect bias 

in a specific direction (with the possible 

exception of the South African cohort), 

Toxichemica, Inc. (2004) considered 

possible biases in either direction by 

assuming that exposure was underestimated by 100% (i.e., the true 

exposure was twice the estimated) or 

over-estimated by 100% (i.e., the true 

exposure was half the estimated) for any 

given cohort in the original pooled 

dataset. For the conditional logistic 

regression model using log cumulative 

exposure with a 15-year lag, doubling or 

halving the exposure for a specific study 

resulted in virtually no change in the 

exposure-response coefficient for that 

study or for the pooled analysis overall. 

Therefore, based on the results of the 

uncertainty analysis, OSHA believes 

that misclassification errors of a 

reasonable magnitude in the estimation 

of historical exposures for the 10 cohort 

studies were not likely to have 

substantially biased risk estimates 

derived from the exposure-response 

model used by Steenland et al. (2001a). 

b. Rice et al. (2001) Analysis of 

Diatomaceous Earth Workers 

Rice et al. (2001) applied a variety of 

exposure-response models to the same 

California diatomaceous earth cohort 

data originally reported on by 

Checkoway et al. (1993, 1996, 1997) and 

included in the pooled analysis 

conducted by Steenland et al. (2001a) 

described above. The cohort consisted 

of 2,342 white males employed for at 

least one year between 1942 and 1987 

in a California diatomaceous earth 

mining and processing plant. The cohort 

was followed until 1994, and included 

77 lung cancer deaths. Rice et al. (2001) 

relied on the dust exposure assessment 

developed by Seixas et al. (1997) from 

company records of over 6,000 samples 

collected from 1948 to 1988; cristobalite 

was the predominate form of crystalline 

silica to which the cohort was exposed. 

Analysis was based on both Poisson 

regression models Cox’s proportional 

hazards models with various functions 

of cumulative silica exposure in mg/m3- 

years to estimate the relationship 

between silica exposure and lung cancer 

mortality rate. Rice et al. (2001) reported 

that exposure to crystalline silica was a 

significant predictor of lung cancer 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56314 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

mortality for nearly all of the models 

employed, with the linear relative risk 

model providing the best fit to the data 

in the Poisson regression analysis. 

c. Attfield and Costello (2004) Analysis 

of Granite Workers 

Attfield and Costello (2004) analyzed 

the same U.S. granite cohort originally 

studied by Costello and Graham (1988) 

and Davis et al. (1983) and included in 

the Steenland et al. (2001a) pooled 

analysis, consisting of 5,414 male 

granite workers who were employed in 

the Vermont granite industry between 

1950 and 1982 and who had received at 

least one chest x-ray from the 

surveillance program of the Vermont 

Department of Industrial Hygiene. Their 

2004 report extended follow-up from 

1982 to 1994, and found 201 deaths. 

Workers’ cumulative exposures were 

estimated by Davis et al. (1983) based on 

historical exposure data collected in six 

environmental surveys conducted 

between 1924 and 1977, plus work 

history information. 

Using Poisson regression models and 

seven cumulative exposure categories, 

the authors reported that the results of 

the categorical analysis showed a 

generally increasing trend of lung 

cancer rate ratios with increasing 

cumulative exposure, with seven lung 

cancer death rate ratios ranging from 

1.18 to 2.6. A complication of this 

analysis was that the rate ratio for the 

highest exposure group in the analysis 

(cumulative exposures of 6.0 mg/m3- 

years or higher) was substantially lower 

than those for other exposure groups. 

Attfield and Costello (2004) reported 

that the best-fitting model was based on 

a 15-year lag, use of untransformed 

cumulative exposure, and omission of 

the highest exposure group. 

The authors argued that it was 

appropriate to base their risk estimates 

on a model that was fitted without the 

highest exposure group for several 

reasons. They believed the underlying 

exposure data for the high-exposure 

group was weaker than for the others, 

and that there was a greater likelihood 

that competing causes of death and 

misdiagnoses of causes of death 

attenuated the lung cancer death rate. 

Second, all of the remaining groups 

comprised 85 percent of the deaths in 

the cohort and showed a strong linear 

increase in lung cancer mortality with 

increasing exposure. Third, Attfield and 

Costello (2004) believed that the 

exposure-response relationship seen in 

the lower exposure groups was more 

relevant given that the exposures of 

these groups were within the range of 

current occupational standards. Finally, 

the authors stated that risk estimates 

derived from the model after excluding 

the highest exposure group were more 

consistent with other published risk 

estimates than was the case for 

estimates derived from the model using 

all exposure groups. Because of these 

reasons, OSHA believes it is appropriate 

to rely on the model employed by 

Attfield and Costello (2004) after 

omitting the highest exposure group. 

d. Kuempel et al. (2001) Rat-Based 

Model for Human Lung Cancer 

Kuempel et al. (2001) published a ratbased toxicokinetic/toxicodynamic 

model for silica exposure for predicting 

human lung cancer, based on lung 

burden concentrations necessary to 

cause the precursor events that can lead 

to adverse physiological effects in the 

lung. These adverse physiological 

effects can then lead to lung fibrosis and 

an indirect genotoxic cause of lung 

cancer. The hypothesized first step, or 

earliest expected response, in these 

disease processes is chronic lung 

inflammation, which the authors 

consider as a disease limiting step. 

Since the NOAEL of lung burden 

associated with this inflammation, 

based on the authors’ rat-to-human lung 

model conversion, is the equivalent of 

exposure to 0.036 mg/m3 (Mcrit) for 45 

years, exposures below this level would 

presumably not lead to (based on an 

indirect genotoxic mechanism) lung 

cancer, at least in the ‘‘average 

individual.’’ Since silicosis also is 

inflammation mediated, this exposure 

could also be considered to be an 

average threshold level for that disease 

as well. 

Kuempel et al. (2001) have used their 

rat-based lung cancer model with 

human data, both to validate their 

model and to estimate the lung cancer 

risk as a function of quartz lung burden. 

First they ‘‘calibrated’’ human lung 

burdens from those in rats based on 

exposure estimates and lung autopsy 

reports of U.S. coal miners. Then they 

validated these lung burden estimates 

using quartz exposure data from U.K. 

coal miners. Using these human lung 

burden/exposure concentration 

equivalence relationships, they then 

converted the cumulative exposure-lung 

cancer response slope estimates from 

both the California diatomaceous earth 

workers (Rice et al., 2001) and Vermont 

granite workers (Attfield and Costello, 

2001) to lung burden-lung cancer 

response slope estimates. Finally, they 

used these latter slope estimates in a life 

table program to estimate lung cancer 

risk associated with their ‘‘threshold’’ 

exposure of 0.036 mg/m3 and to the 

OSHA PEL and NIOSH REL. Comparing 

the estimates from the two 

epidemiology studies with those based 

on a male rat chronic silica exposure 

study the authors found that, ’’ the lung 

cancer excess risk estimates based on 

male rat data are approximately three 

times higher than those based on the 

male human data.’’ Based on this 

modeling and validation exercise, 

Keumpel et al. concluded, ‘‘the ratbased estimates of excess lung cancer 

risk in humans exposed to crystalline 

silica are reasonably similar to those 

based on two human occupational 

epidemiology studies.’’ 

Toxichemica, Inc. (2004) investigated 

whether use of the dosimetry model 

would substantially affect the results of 

the pooled lung cancer data analysis 

initially conducted by Steenland et al. 

(2001a). They replicated the lung 

dosimetry model using Kuempel et al.’s 

(2001) reported median fit parameter 

values, and compared the relationship 

between log cumulative exposure and 

15-year lagged lung burden at the age of 

death in case subjects selected for the 

pooled case-control analysis. The two 

dose metrics were found to be highly 

correlated (r=0.99), and models based 

on either log silica lung burden or log 

cumulative exposure were similarly 

good predictors of lung cancer risk in 

the pooled analysis (nearly identical 

log-likelihoods of –4843.96 and— 

4843.996, respectively). OSHA believes 

that the Kuempel et al. (2001) analysis 

is a credible attempt to quantitatively 

describe the retention and accumulation 

of quartz in the lung, and to relate the 

external exposure and its associated 

lung burden to the inflammatory 

process. However, using the lung 

burden model to convert the cumulative 

exposure coefficients to a different 

exposure metric appears to add little 

additional information or insight to the 

risk assessments conducted on the 

diatomaceous earth and granite cohort 

studies. Therefore, for the purpose of 

quantitatively evaluating lung cancer 

risk in exposed workers, OSHA has 

chosen to rely on the epidemiology 

studies themselves and the cumulative 

exposure metrics used in those studies. 

e. Hughes et al. (2001), McDonald et al. 

(2001), and McDonald et al. (2005) 

Study of North American Industrial 

Sand Workers 

McDonald et al. (2001), Hughes et al. 

(2001) and McDonald et al. (2005) 

followed up on a cohort study of North 

American industrial sand workers that 

overlapped with the industrial sand 

cohort (18 plants, 4,626 workers) 

studied by Steenland and Sanderson 

(2001) and included in Steenland et al.’s 

(2001a) pooled cohort analysis. The 

McDonald et al. (2001) follow-up cohort 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56315 

included 2,670 men employed before 

1980 for three years or more in one of 

nine North American (8 U.S. and 1 

Canadian) sand-producing plants, 

including 1 large associated office 

complex. Information on cause of death 

was obtained, from 1960 through 1994, 

for 99 percent of the deceased workers 

for a total 1,025 deaths representing 38 

percent of the cohort. A nested casecontrol study and analysis based on 90 

lung cancer deaths from this cohort was 

also conducted by Hughes et al. (2001). 

A later update through 2000, of both the 

cohort and nested case-control studies 

by McDonald et al. (2005), eliminated 

the Canadian plant, following 2,452 

men from the eight U.S. plants. For the 

lung cancer case-control part of the 

study the update included 105 lung 

cancer deaths. Both the initial and 

updated case control studies used up to 

two controls per case. 

Although the cohort studies provided 

evidence of increased risk of lung 

cancer (SMR = 150, p = 0.001, based on 

U.S. rates) for deaths occurring 20 or 

more years from hire, the nested casecontrol studies, Hughes et al. (2001) and 

McDonald et al. (2005), allowed for 

individual job, exposure, and smoking 

histories to be taken into account in the 

exposure-response analysis for lung 

cancer. Both of these case-control 

analyses relied on an analysis of 

exposure information reported by 

Sanderson et al. (2000) and by Rando et 

al. (2001) to provide individual 

estimates of average and cumulative 

exposure. Statistically significant 

positive exposure-response trends for 

lung cancer were found for both 

cumulative exposure (lagged 15 years) 

and average exposure concentration, but 

not for duration of employment, after 

controlling for smoking. A monotonic 

increase was seen for both lagged and 

unlagged cumulative exposure when the 

four upper exposure categories were 

collapsed into two. With exposure 

lagged 15 years and after adjusting for 

smoking, increasing quartiles of 

cumulative silica exposure were 

associated with lung cancer mortality 

(odds ratios of 1.00, 0.84, 2.02 and 2.07, 

p-value for trend=0.04). There was no 

indication of an interaction effect of 

smoking and cumulative silica exposure 

(Hughes et al., 2001). 

OSHA considers this Hughes et al. 

(2001) study and analysis to be of high 

enough quality to provide risk estimates 

for excess lung cancer for silica 

exposure to industrial sand workers. 

Using the median cumulative exposure 

levels of 0, 0.758, 2.229 and 6.183 mg/ 

m3-years, Hughes et al. estimated lung 

cancer odds ratios, ORs (no. of deaths), 

for these categories of 1.00 (14), 0.84 

(15), 2.02 (31), and 2.07 (30), 

respectively, on a 15-year lag basis (pvalue for trend=0.04.) For the updated 

nested case control analysis, McDonald 

et al. (2005) found very similar results, 

with exposure lagged 15 years and, after 

adjusting for smoking, increasing 

quartiles of cumulative silica exposure 

were associated with lung cancer ORs 

(no. of deaths) of 1.00 (13), 0.94 (17), 

2.24 (38), and 2.66 (37) (p-value for 

trend=0.006). Because the Hughes et al. 

(2001) report contained information that 

allowed OSHA to better calculate 

exposure-response estimates and 

because of otherwise very similar results 

in the two papers, OSHA has chosen to 

base its lifetime excess lung cancer risk 

estimate for these industrial sand 

workers on the Hughes et al. (2001) 

case-control study. Using the median 

exposure levels of 0, 0.758, 2.229 and 

6.183 mg-years/m3, respectively, for 

each of the four categories described 

above, and using the model: ln OR = a 

+ b × Cumulative Exposure, the 

coefficient for the exposure estimate 

was b = 0.13 per (mg/m3-years), with a 

standard error of b = 0.074 (calculated 

from the trend test p-value in the same 

paper). In this model, with background 

lung cancer risks of about 5 percent, the 

OR provides a suitable estimate of the 

relative risk. 

f. Miller et al. (2007) and Miller and 

MacCalman (2009) Study of British Coal 

Workers Exposed to Respirable Quartz 

Miller et al. (2007) and Miller and 

MacCalman (2009) continued a followup mortality study, begun in 1970, of 

18,166 coalminers from 10 British 

coalmines initially followed through the 

end of 1992 (Miller et al., 1997). The 

two recent reports on mortality analyzed 

the cohort of 17,800 miners and 

extended the analysis through the end 

of 2005. By that time there were 516,431 

person years of observation, an average 

of 29 years per miner, with 10,698 

deaths from all causes. Causes of deaths 

of interest included pneumoconiosis, 

other non-malignant respiratory 

diseases (NMRD), lung cancer, stomach 

cancer, and tuberculosis. Three of the 

strengths of this study are its use of 

detailed time-exposure measurements of 

both quartz and total mine dust, 

detailed individual work histories, and 

individual smoking histories. However, 

the authors noted that no additional 

exposure measurements were included 

in the updated analysis, since all the 

mines had closed by the mid 1980’s. 

For this cohort mortality study there 

were analyses using both external 

(regional age-time and cause specific 

mortality rates) internal controls. For 

the analysis from external mortality 

rates, the all-cause mortality SMR from 

1959 through 2005 was 100.9 (95% C.I., 

99.0–102.8), based on all 10,698 deaths. 

However, these death ratios were not 

uniform over time. For the period from 

1990 to 2005, the all-cause SMR was 

109.6 (95% C.I., 106.5–112.8), while the 

ratios for previous periods were less 

than 100. This pattern of recent 

increasing SMRs was also seen in the 

recent cause-specific death rate for lung 

cancer, SMR=115.7 (95% C.I., 104.8– 

127.7). For the analysis based on 

internal rates and using Cox regression 

methods, the relative risk for lung 

cancer risk based on a cumulative 

quartz exposure equivalent to 

approximately 0.055 mg/m3 for 45 years 

was RR = 1.14 (95% C.I., 1.04 to 1.25). 

This risk is adjusted for concurrent coal 

dust exposure and smoking status, and 

incorporated a 15-year lag in quartz 

exposures. The analysis showed a strong 

effect for smoking (independent of 

quartz exposure) on lung cancer. For 

lung cancer, OSHA believes that the 

analyses based on the Cox regression 

method provides strong evidence that 

for these coal miners’ quartz exposures 

were associated with increased lung 

cancer risk, but that simultaneous 

exposures to coal dust did not cause 

increased lung cancer risk. To estimate 

lung cancer risk from this study, OSHA 

estimated the regression slope for a loglinear relative risk model based on the 

Miller and MacCalman’s (2009) finding 

of a relative risk of 1.14 for a cumulative 

exposure of 0.055 mg/m3-years. 

2. Summary of OSHA’s Estimates of 

Lung Cancer Mortality Risk 

Tables VI–1 and VI–2 summarize the 

excess lung cancer risk estimates from 

occupational exposure to crystalline 

silica, based on five of the six lung 

cancer risk assessments discussed 

above. OSHA’s estimates of lifetime 

excess lung cancer risk associated with 

45 years of exposure to crystalline silica 

at 0.1 mg/m3 (approximately the current 

general industry PEL) range from 13 to 

60 deaths per 1,000 workers. For 

exposure to the proposed PEL of 0.05 

mg/m3, the lifetime risk estimates 

calculated by OSHA are in the range of 

6 to 26 deaths per 1,000 workers. For a 

45-year exposure at the proposed action 

level of 0.025 mg/m3, OSHA estimates 

the risk to range from 3 to 23 deaths per 

1,000 workers. The results from these 

assessments are reasonably consistent 

despite the use of data from different 

cohorts and the reliance on different 

analytical techniques for evaluating 

dose-response relationships. 

Furthermore, OSHA notes that in this 

range of exposure, 0.025—0.1 mg/m3, 

there is statistical consistency between 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56316 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

the risk estimates, as evidenced by the 

considerable overlap in the 95-percent 

confidence intervals of the risk 

estimates presented in Table VI–1. 

OSHA also estimates the lung cancer 

risk associated with 45 years of 

exposure to the current construction/

shipyard PEL (in the range of 0.25 to 0.5 

mg/m3) to range from 37 to 653 deaths 

per 1,000 workers. Exposure to 0.25 or 

0.5 mg/m3 over 45 years represents 

cumulative exposures of 11.25 and 22.5 

mg-years/m3, respectively. This range of 

cumulative exposure is well above the 

median cumulative exposure for most of 

the cohorts used in the risk assessment, 

primarily because most of the 

individuals in these cohorts had not 

been exposed for as long as 45 years. 

Thus, estimating lung cancer excess 

risks over this higher range of 

cumulative exposures of interest to 

OSHA required some degree of 

extrapolation and adds uncertainty to 

the estimates. 

C. Silicosis and Non-Malignant 

Respiratory Disease Mortality 

There are two published quantitative 

risk assessment studies of silicosis and 

non-malignant respiratory disease 

(NMRD) mortality; a pooled analysis of 

silicosis mortality by Mannetje et al. 

(2002b) of data from six epidemiological 

studies, and an exposure-response 

analysis of NMRD mortality among 

diatomaceous earth workers (Park et al., 

2002). 

1. Mannetje et al. (2002b) Six Cohort 

Pooled Analysis 

The Mannetje et al. (2002b) silicosis 

analysis was part of the IARC ten cohort 

pooled study included in the Steenland 

et al. (2001a) lung cancer mortality 

analysis above. These studies included 

18,634 subjects and 170 silicosis deaths 

(n = 150 for silicosis, and n = 20 

unspecified pneumoconiosis). The 

silicosis deaths had a median duration 

of exposure of 28 years, a median 

cumulative exposure of 7.2 mg/m3- 

years, and a median average exposure of 

0.26 mg/m3, while the respective values 

of the whole cohort were 10 years, 0.62 

mg/m3-years, and 0.07 mg/m3. Rates for 

silicosis adjusted for age, calendar time, 

and study were estimated by Poisson 

regression; rates increased nearly 

monotonically with deciles of 

cumulative exposure, from a mortality 

rate of 5/100,000 person-years in the 

lowest exposure category (0–0.99 mg/

m3-years) to 299/100,000 person-years 

in the highest category (>28.10 mg/m3- 

years). Quantitative estimates of 

exposure to respirable silica (mg/m3) 

were available for all six cohorts 

(Mannetje et al. 2002a). Lifetime risk of 

silicosis mortality was estimated by 

accumulating mortality rates over time 

using the formula 

Risk = 1 ¥ exp(¥ètime * rate). 

To estimate the risk of silicosis 

mortality at the current and proposed 

PELs, OSHA used the model described 

by Mannetje et al. (2002b) to estimate 

risk to age 85 but used rate ratios that 

were estimated from a nested casecontrol design that was part of a 

sensitivity analysis conducted by 

Toxichemica, Inc. (2004), rather than 

the Poisson regression originally 

conducted by Mannetje et al. (2002b). 

The case-control design was selected 

because it was expected to better control 

for age; in addition, the rate ratios 

derived from the case-control study 

reflect exposure measurement 

uncertainty via conduct of a Monte 

Carlo analysis (Toxichemica, Inc., 2004). 

2. Park et al. (2002) Study of 

Diatomaceous Earth Workers 

Park et al. (2002) analyzed the 

California diatomaceous earth cohort 

data originally studied by Checkoway et 

al. (1997), consisting of 2,570 

diatomaceous earth workers employed 

for 12 months or more from 1942 to 

1994, to quantify the relationship 

between exposure to cristobalite and 

mortality from chronic lung disease 

other than cancer (LDOC). Diseases in 

this category included pneumoconiosis 

(which included silicosis), chronic 

bronchitis, and emphysema, but 

excluded pneumonia and other 

infectious diseases. Industrial hygiene 

data for the cohort were available from 

the employer for total dust, silica 

(mostly cristobalite), and asbestos. Park 

et al. (2002) used the exposure 

assessment previously reported by 

Seixas et al. (1997) and used by Rice et 

al. (2001) to estimate cumulative 

crystalline silica exposures for each 

worker in the cohort based on detailed 

work history files. The mean silica 

concentration for the cohort overall was 

0.29 mg/m3 over the period of 

employment (Seixas et al., 1997). The 

mean cumulative exposure values for 

total respirable dust and respirable 

crystalline silica were 7.31 and 2.16 mg/ 

m3-year, respectively. Similar 

cumulative exposure estimates were 

made for asbestos. Smoking information 

was available for about 50 percent of the 

cohort and for 22 of the 67 LDOC deaths 

available for analysis, permitting Park et 

al. (2002) to at least partially adjust for 

smoking. Estimates of LDOC mortality 

risks were derived via Poisson and 

Cox’s proportional hazards models; a 

variety of relative rate model forms were 

fit to the data, with a linear relative rate 

model being selected for risk estimation. 

3. Summary Risk Estimates for Silicosis 

and NMRD Mortality 

Table VI–2 presents OSHA’s risk 

estimates for silicosis and NMRD 

mortality derived from the Mannetje et 

al. (2002b) and Park et al. (2002) studies, 

respectively. For 45 years of exposure to 

the current general industry PEL 

(approximately 0.1 mg/m3 respirable 

crystalline silica), OSHA’s estimates of 

excess lifetime risk are 11 deaths per 

1,000 workers for the pooled analysis 

and 83 deaths per 1,000 workers based 

on Park et al.’s (2002) estimates. At the 

proposed PEL, estimates of silicosis and 

NMRD mortality are 7 and 43 deaths per 

1,000, respectively. For exposures up to 

0.25 mg/m3, the estimates based on Park 

et al. are about 5 to 11 times as great as 

those calculated for the pooled analysis 

of silicosis mortality (Mannetje et al., 

2002b). However, these two sets of risk 

estimates are not directly comparable. 

First, the Park et al. analysis used 

untransformed cumulative exposure as 

the exposure metric, whereas the 

Mannertje et al. analysis used log 

cumulative exposure, which causes the 

exposure-response to flatten out in the 

higher exposure ranges. Second, the 

mortality endpoint for the Park et al. 

(2002) analysis is death from all noncancer lung diseases, including 

pneumoconiosis, emphysema, and 

chronic bronchitis, whereas the pooled 

analysis by Mannetje et al. (2002b) 

included only deaths coded as silicosis 

or other pneumoconiosis. Less than 25 

percent of the LDOC deaths in the Park 

et al. (2002) analysis were coded as 

silicosis or other pneumoconiosis (15 of 

67). As noted by Park et al. (2002), it is 

likely that silicosis as a cause of death 

is often misclassified as emphysema or 

chronic bronchitis; thus, Mannetje et 

al.’s (2002b) selection of deaths may 

tend to underestimate the true risk of 

silicosis mortality, and Park et al.’s 

(2002) analysis would more fairly 

capture the total respiratory mortality 

risk from all non-malignant causes, 

including silicosis and chronic 

obstructive pulmonary disease. 

D. Renal Disease Mortality 

Steenland et al. (2002a) examined 

renal disease mortality in three cohorts 

and evaluated exposure-response 

relationships from the pooled cohort 

data. The three cohorts included U.S. 

gold miners (Steenland and Brown, 

1995a), U.S. industrial sand workers 

(Steenland et al., 2001b), and Vermont 

granite workers (Costello and Graham, 

1988), all three of which are included in 

both the lung cancer mortality and 

silicosis mortality pooled analyses 

reported above. Follow up for the U.S. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56317 

gold miners study was extended six 

years from that in the other pooled 

analyses. Steenland et al. (2002a) 

reported that these cohorts were chosen 

because data were available for both 

underlying cause mortality and multiple 

cause mortality; this was believed 

important because renal disease is often 

listed on death certificates without 

being identified as an underlying cause 

of death. In the three cohorts, there were 

51 total renal disease deaths using 

underlying cause, and 204 total renal 

deaths using multiple cause mortality. 

The combined cohort for the pooled 

analysis (Steenland et al., 2002a) 

consisted of 13,382 workers with 

exposure information available for 

12,783 (95 percent). Exposure matrices 

for the three cohorts had been used in 

previous studies (Steenland and Brown, 

1995a; Attfield and Costello, 2001; 

Steenland et al., 2001b). The mean 

duration of exposure, the mean 

cumulative exposure, and the mean 

concentration of respirable silica for the 

pooled cohort were 13.6 years, 1.2 mg/ 

m3-years, and 0.07 mg/m3, respectively. 

SMRs (compared to the U.S. population) 

for renal disease (acute and chronic 

glomerulonephritis, nephrotic 

syndrome, acute and chronic renal 

failure, renal sclerosis, and nephritis/

nephropathy) were statistically 

significantly elevated using multiple 

cause data (SMR 1.29, 95% CI 1.10– 

1.47, 193 deaths) and underlying cause 

data (SMR 1.41, 95% CI 1.05–1.85, 51 

observed deaths). 

OSHA’s estimates of renal disease 

mortality appear in Table VI–2. Based 

on the life table analysis, OSHA 

estimates that exposure to the current 

(0.10 mg/m3) and proposed general 

industry PEL (0.0.05 mg/m3) over a 

working life would result in a lifetime 

excess renal disease risk of 39 (95% CI 

2–200) and 32 (95% CI 1.7–147) deaths 

per 1,000, respectively. For exposure to 

the current construction/shipyard PEL, 

OSHA estimates the excess lifetime risk 

to range from 52 (95% CI 2.2–289) to 63 

(95% CI 2.5–368) deaths per 1,000 

workers. 

E. Silicosis Morbidity 

OSHA’s Preliminary QRA summarizes 

the principal cross-sectional and cohort 

studies that have quantitatively 

characterized relationships between 

exposure to crystalline silica and 

development of radiographic evidence 

of silicosis. Each of these studies relied 

on estimates of cumulative exposure to 

evaluate the relationship between 

exposure and silicosis prevalence in the 

worker populations examined. The 

health endpoint of interest in these 

studies is the appearance of opacities on 

chest roentgenograms indicative of 

pulmonary fibrosis. 

The International Labour 

Organization’s (ILO) 1980 International 

Classification of Radiographs of the 

Pneumoconioses is accepted as the 

standard against which chest 

radiographs are measured in 

epidemiologic studies, for medical 

surveillance and for clinical evaluation. 

According to this standard, if 

radiographic findings are or may be 

consistent with pneumoconiosis, then 

the size, shape, and extent of profusion 

of opacities are characterized by 

comparing the radiograph to standard 

films. Classification by shape (rounded 

vs. irregular) and size involves 

identifying primary and secondary types 

of small opacities on the radiograph and 

classifying them into one of six size/

shape categories. The extent of 

profusion is judged from the 

concentrations of opacities as compared 

with that on the standard radiographs 

and is graded on a 12-point scale of four 

major categories (0–3, with Category 0 

representing absence of opacities), each 

with three subcategories. Most of the 

studies reviewed by OSHA considered a 

finding consistent with an ILO 

classification of 1/1 to be a positive 

diagnosis of silicosis, although some 

also considered an x-ray classification of 

1/0 or 0/1 to be positive. 

Chest radiography is not the most 

sensitive tool used to diagnose or detect 

silicosis. In 1993, Hnizdo et al. reported 

the results of a study that compared 

autopsy and radiological findings of 

silicosis in a cohort of 557 white South 

African gold miners. The average period 

from last x-ray to autopsy was 2.7 years. 

Silicosis was not diagnosed 

radiographically for over 60 percent of 

the miners for whom pathological 

examination of lung tissue showed 

slight to marked silicosis. The 

likelihood of false negatives (negative by 

x-ray, but silicosis is actually present) 

increased with years of mining and 

average dust exposure of the miners. 

The low sensitivity seen for 

radiographic evaluation suggests that 

risk estimates derived from radiographic 

evidence likely understate the true risk 

of developing fibrotic lesions as a result 

of exposure to crystalline silica. 

OSHA’s Preliminary QRA examines 

multiple studies from which silicosis 

occupational morbidity risks can be 

estimated. The studies evaluated fall 

into three major types. Some are crosssectional studies in which radiographs 

taken at a point in time were examined 

to ascertain cases (Kreiss and Zhen, 

1996; Love et al., 1999; Ng and Chan, 

1994; Rosenman et al., 1996; 

Churchyard et al., 2003, 2004); these 

radiographs may have been taken as part 

of a health survey conducted by the 

investigators or represent the most 

recent chest x-ray available for study 

subjects. Other studies were designed to 

examine radiographs over time in an 

effort to determine onset of disease. 

Some of these studies examined 

primarily active, or current, workers 

(Hughes et al., 1998; Muir et al., 1989a, 

1989b; Park et al., 2002), while others 

included both active and retired 

workers (Chen et al., 2001, 2005; Hnizdo 

and Sluis-Cremer, 1993; Miller et al., 

1998; Buchanan et al., 2003; Steenland 

and Brown, 1995b). 

Even though OSHA has presented 

silicosis risk estimates for all of the 

studies identified, the Agency is relying 

primarily on those studies that 

examined radiographs over time and 

included both active and retired 

workers. It has been pointed out by 

others (Chen et al., 2001; Finkelstein, 

2000; NIOSH, 2002) that lack of followup of retired workers consistently 

resulted in lower risk estimates 

compared to studies that included 

retired workers. OSHA believes that the 

most reliable estimates of silicosis 

morbidity, as detected by chest 

radiographs, come from the studies that 

evaluated radiographs over time, 

included radiographic evaluation of 

workers after they left employment, and 

derived cumulative or lifetime estimates 

of silicosis disease risk. Brief 

descriptions of these cumulative risk 

studies used to estimate silicosis 

morbidity risks are presented below. 

1. Hnizdo and Sluis Cremer (1993) 

Study of South African White Gold 

Miners 

Hnizdo and Sluis-Cremer (1993) 

described the results of a retrospective 

cohort study of 2,235 white gold miners 

in South Africa. These workers had 

received annual examinations and chest 

x-rays while employed; most returned 

for occasional examinations after 

employment. A case was defined as one 

with an x-ray classification of ILO 1/1 

or greater. A total of 313 miners had 

developed silicosis and had been 

exposed for an average of 27 years at the 

time of diagnosis. Forty-three percent of 

the cases were diagnosed while 

employed and the remaining 57 percent 

were diagnosed an average of 7.4 years 

after leaving the mines. The average 

latency for the cohort was 35 years 

(range of 18–50 years) from start of 

exposure to diagnosis. 

The average respirable dust exposure 

for the cohort overall was 0.29 mg/m3

(range 0.11–0.47), corresponding to an 

estimated average respirable silica 

concentration of 0.09 mg/m3 (range 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56318 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

0.033–0.14). The average cumulative 

dust exposure for the overall cohort was 

6.6 mg/m3-years (range 1.2–18.7), or an 

average cumulative silica exposure of 

1.98 mg/m3-years (range 0.36–5.61). 

OSHA believes that the exposure 

estimates for the cohort are uncertain 

given the need to rely on particle count 

data generated over a fairly narrow 

production period. 

Silicosis risk increased exponentially 

with cumulative exposure to respirable 

dust and was modeled using log-logistic 

regression. Using the exposure-response 

relationship developed by Hnizdo and 

Sluis-Cremer (1993), and assuming a 

quartz content of 30 percent in 

respirable dust, Rice and Stayner (1995) 

and NIOSH (2002) estimated the risk of 

silicosis to be 70 percent and 13 percent 

for a 45-year exposure to 0.1 and 0.05 

mg/m3 respirable crystalline silica, 

respectively. 

2. Steenland and Brown (1995b) Study 

of South Dakota Gold Miners 

Three thousand three hundred thirty 

South Dakota gold miners who had 

worked at least a year underground 

between 1940 and 1965 were studied by 

Steenland and Brown (1995b). Workers 

were followed though 1990 with 1,551 

having died; loss to follow up was low 

(2 percent). Chest x-rays taken in crosssectional surveys in 1960 and 1976 and 

death certificates were used to ascertain 

cases of silicosis. One hundred twenty 

eight cases were found via death 

certificate, 29 by x-ray (defined as ILO 

1/1 or greater), and 13 by both. Nine 

percent of deaths had silicosis 

mentioned on the death certificate. 

Inclusion of death certificate diagnoses 

probably increases the risk estimates 

from this study compared to those that 

rely exclusively on radiographic 

findings to evaluate silicosis morbidity 

risk (see discussion of Hnizdo et al. 

(1993) above). 

Exposure was estimated by 

conversion of impinger (particle count) 

data and was based on measurements 

indicating an average of 13 percent 

silica in the dust. Based on these data, 

the authors estimated the mean 

exposure concentration to be 0.05 mg/

m3 for the overall cohort, with those 

hired before 1930 exposed to an average 

of 0.15 mg/m3. The average duration of 

exposure for cases was 20 years (s.d = 

8.7) compared to 8.2 years (s.d = 7.9) for 

the rest of the cohort. This study found 

that cumulative exposure was the best 

disease predictor, followed by duration 

of exposure and average exposure. 

Lifetime risks were estimated from 

Poisson regression models using 

standard life table techniques. The 

authors estimated a risk of 47 percent 

associated with 45 years of exposure to 

0.09 mg/m3 respirable crystalline silica, 

which reduced to 35 percent after 

adjustment for age and calendar time. 

3. Miller et al. (1995, 1998) and 

Buchanan et al. (2003) Study of Scottish 

Coal Miners 

Miller et al. (1995, 1998) and 

Buchanan et al. (2003) reported on a 

1990/1991 follow-up study of 547 

survivors of a 1,416 member cohort of 

Scottish coal workers from a single 

mine. These men had all worked in the 

mine during a period between early 

1971 and mid 1976, during which they 

had experienced ‘‘unusually high 

concentrations of freshly cut quartz in 

mixed coalmine dust. The population’s 

exposures to both coal and quartz dust 

had been measured in unique detail, for 

a substantial proportion of the men’s 

working lives.’’ Thus, this cohort 

allowed for the study of the effects of 

both higher and lower silica 

concentrations, and exposure-rate 

effects on the development of silicosis. 

The 1,416 men had all had previous 

radiographs dating from before, during, 

or just after this high concentration 

period, and the 547 participating 

survivors received their follow-up chest 

x-rays between November 1990 and 

April 1991. Follow-up interviews 

consisted of questions on current and 

past smoking habits, and occupational 

history since leaving the coal mine, 

which closed in 1981. 

Silicosis cases were identified as such 

if the median classification of the three 

readers indicated an ILO (1980) 

classification of 1/0 or greater, plus a 

progression from the earlier reading. Of 

the 547 men, 203 (38 percent) showed 

progression of at least one ILO category 

from the 1970’s surveys to the 1990–91 

survey; in 128 of these (24 percent) 

there was progression of two or more 

steps. In the 1970’s survey 504 men had 

a profusion score of 0; of these, 120 (24 

percent) progressed to an ILO 

classification of 1/0 or greater. Of the 36 

men who had shown earlier profusions 

of 1/0 or greater, 27 (75 percent) showed 

further progression at the 1990/1991 

follow-up. Only one subject showed a 

regression from any earlier reading, and 

that was slight, from ILO 1/0 to 0/1. 

To study the effects of exposure to 

high concentrations of quartz dust, the 

Buchanan et al. (2003) analysis 

presented the results of logistic 

regression modeling that incorporated 

two independent terms for cumulative 

exposure, one arising from exposure to 

concentrations less than 2 mg/m3

respirable quartz and the other from 

exposure to concentrations greater than 

or equal to 2 mg/m3. Both of the 

cumulative quartz exposure 

concentration variables were ‘‘highly 

statistically significant in the presence 

of the other,’’ and independent of the 

presence of coal dust. Since these quartz 

variables were in the same units, g–hr/ 

m3, the authors noted that coefficient for 

exposure concentrations equal to or 

above 2.0 mg/m3 was 3 times that of the 

coefficient for concentrations less than 

2.0 mg/m3. From this, the authors 

concluded that their analysis showed 

that ‘‘the risk of silicosis over a working 

lifetime can rise dramatically with 

exposure to such high concentrations 

over a timescale of merely a few 

months.’’ 

Buchanan et al., (2003) provided 

analysis and risk estimates only for 

silicosis cases defined as having an xray classified as ILO 2/1+, after 

adjusting for the disproportionately 

severe effect of exposure to high 

concentrations on silicosis risk. 

Estimating the risk of acquiring a chest 

x-ray classified as ILO 1/0+ from the 

Buchanan (2003) or the earlier Miller et 

al. (1995, 1998) publications can only be 

roughly approximated because of the 

limited summary information included; 

this information suggests that the risk of 

silicosis defined as an ILO classification 

of 1/0+ could be about three times 

higher than the risk of silicosis defined 

as an ILO 2/1+ x-ray. OSHA has a high 

degree of confidence in the estimates of 

progression to stages 2/1+ from this 

Scotland coal mine study, mainly 

because of the highly detailed and 

extensive exposure measurements, the 

radiographic records, and the detailed 

analyses of high exposure-rate effects. 

4. Chen et al. (2001) Study of Tin 

Miners 

Chen et al. (2001) reported the results 

of a retrospective study of a Chinese 

cohort of 3,010 underground miners 

who had worked in tin mines at least 

one year between 1960 and 1965. They 

were followed through 1994, by which 

time 2,426 (80.6%) workers had either 

retired or died, and only 400 (13.3%) 

remained employed at the mines. 

The study incorporated occupational 

histories, dust measurements and 

medical examination records. Exposure 

data consisted of high-flow, short-term 

gravimetric total dust measurements 

made routinely since 1950; the authors 

used data from 1950 to represent earlier 

exposures since dust control measures 

were not implemented until 1958. 

Results from a 1998–1999 survey 

indicated that respirable silica 

measurements were 3.6 percent (s.d = 

2.5 percent) of total dust measurements. 

Annual radiographs were taken since 

1963 and all cohort members continued 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56319 

to have chest x-rays taken every 2 or 3 

years after leaving work. Silicosis was 

diagnosed when at least 2 of 3 

radiologists classified a radiograph as 

being a ‘‘suspected case’’ or at Stage I, 

II, or III under the 1986 Chinese 

pneumoconiosis roentgen diagnostic 

criteria. According to Chen et al. (2001), 

these four categories under the Chinese 

system were found to agree closely with 

ILO categories 0/1, Category 1, Category 

2, and Category 3, respectively, based on 

studies comparing the Chinese and ILO 

classification systems. Silicosis was 

observed in 33.7 percent of the group; 

67.4 percent of the cases developed after 

exposure ended. 

5. Chen et al. (2005) Study of Chinese 

Pottery Workers, Tin Miners, and 

Tungsten Miners 

In a later study, Chen et al. (2005) 

investigated silicosis morbidity risks 

among three cohorts to determine if the 

risk varied among workers exposed to 

silica dust having different 

characteristics. The cohorts consisted of 

4,547 pottery workers, 4,028 tin miners, 

and 14,427 tungsten miners selected 

from a total of 20 workplaces. Cohort 

members included all males employed 

after January 1, 1950 and who worked 

for at least one year between 1960 and 

1974. Radiological follow-up was 

through December 31, 1994 and x-rays 

were scored according to the Chinese 

classification system as described above 

by Chen et al. (2001) for the tin miner 

study. Exposure estimates of cohort 

members to respirable crystalline silica 

were based on the same data as 

described by Chen et al. (2001). In 

addition, the investigators measured the 

extent of surface occlusion of crystalline 

silica particles by alumino-silicate from 

47 dust samples taken at 13 worksites 

using multiple-voltage scanning 

electron microscopy and energy 

dispersive X-ray spectroscopy (Harrison 

et al., 2005); this method yielded 

estimates of the percent of particle 

surface that is occluded. 

Compared to tin and tungsten miners, 

pottery workers were exposed to 

significantly higher mean total dust 

concentrations (8.2 mg/m3, compared to 

3.9 mg/m3 for tin miners and 4.0 mg/m3

for tungsten miners), worked more net 

years in dusty occupations (mean of 

24.9 years compared to 16.4 years for tin 

miners and 16.5 years for tungsten 

miners), and had higher mean 

cumulative dust exposures (205.6 mg/

m3-years compared to 62.3 mg/m3-years 

for tin miners and 64.9 mg/m3-years for 

tungsten miners) (Chen et al., 2005). 

Applying the authors’ conversion 

factors to estimate respirable crystalline 

silica from Chinese total dust 

measurements, the approximate mean 

cumulative exposures to respirable 

silica for pottery, tin, and tungsten 

workers are 6.4 mg/m3-years, 2.4 mg/

m3-years, and 3.2 mg/m3-years, 

respectively. Measurement of particle 

surface occlusion indicated that, on 

average, 45 percent of the surface area 

of respirable particles collected from 

pottery factory samples was occluded, 

compared to 18 percent of the particle 

surface area for tin mine samples and 13 

percent of particle surface area for 

tungsten mines. 

Based on Chen et al. (2005), OSHA 

estimated the cumulative silicosis risk 

associated with 45 years of exposure to 

0.1 mg/m3 respirable crystalline silica (a 

cumulative exposure of 4.5 mg/m3- 

years) to be 6 percent for pottery 

workers, 12 percent for tungsten miners, 

and 40 percent for tin miners. For a 

cumulative exposure of 2.25 mg/m3- 

years (i.e., 45 years of exposure to 0.05 

mg/m3), cumulative silicosis morbidity 

risks were estimated to be 2, 2, and 10 

percent for pottery workers, tungsten 

miners, and tin miners, respectively. 

When cumulative silica exposure was 

adjusted to reflect exposure to surfaceactive quartz particles (i.e., not 

occluded), the estimated cumulative 

risk among pottery workers more closely 

approximated those of the tin and 

tungsten miners, suggesting to the 

authors that alumino-silicate occlusion 

of the crystalline particles in pottery 

factories at least partially explained the 

lower risk seen among workers, despite 

their having been more heavily exposed. 

6. Summary of Silicosis Morbidity Risk 

Estimates. 

Table VI–2 presents OSHA’s risk 

estimates for silicosis morbidity that are 

derived from each of the studies 

described above. Estimates of silicosis 

morbidity derived from the seven 

cohorts in cumulative risk studies with 

post-employment follow-up range from 

60 to 773 per 1,000 workers for 45-year 

exposures to the current general 

industry PEL of 0.10 mg/m3, and from 

20 to 170 per 1,000 workers for a 45- 

year exposure to the proposed PEL of 

0.05 mg/m3. The study results provide 

substantial evidence that the disease can 

progress for years after exposure ends. 

Results from an autopsy study (Hnizdo 

et al., 1993), which found pathological 

evidence of silicosis absent radiological 

signs, suggest that silicosis cases based 

on radiographic diagnosis alone tend to 

underestimate risk since pathological 

evidence of silicosis. Other results 

(Chen et al., 2005) suggest that surface 

properties among various types of silica 

dusts can have different silicosis 

potencies. Results from the Buchanan et 

al. (2003) study of Scottish coal miners 

suggest that short-term exposures to >2 

mg/m3 silica can cause a 

disproportionately higher risk of 

silicosis than would be predicted by 

cumulative exposure alone, suggesting a 

dose-rate effect for exposures to 

concentrations above this level. OSHA 

believes that, given the consistent 

finding of a monotonic exposureresponse relationship for silicosis 

morbidity with cumulative exposure in 

the studies reviewed, that cumulative 

exposure is a reasonable exposure 

metric upon which to base risk 

estimates in the exposure range of 

interest to OSHA (i.e., between 0.025 

and 0.5 mg/m3 respirable crystalline 

silica). 

F. Other Considerations in OSHA’s Risk 

Analysis 

Uncertainties are inherent to any risk 

modeling process and analysis; 

assessing risk and associated 

complexities of silica exposure among 

workers is no different. However, the 

Agency has a high level of confidence 

that the preliminary risk assessment 

results reasonably reflect the range of 

risks experienced by workers exposed to 

silica in all occupational settings. First, 

the preliminary assessment is based on 

an analysis of a wide range of studies, 

conducted in multiple industries across 

a wide range of exposure distributions, 

which included cumulative exposures 

equivalent to 45 years of exposure to 

and below the current PEL. 

Second, risk models employed in this 

assessment are based on a cumulative 

exposure metric, which is the product of 

average daily silica concentration and 

duration of worker exposure for a 

specific job. Consequently, these models 

predict the same risk for a given 

cumulative exposure regardless of the 

pattern of exposure. For example, a 

manufacturing plant worker exposed to 

silica at 0.05 mg/m3 for eight hours per 

day will have the same cumulative 

exposure over a given period of time as 

a construction worker who is exposed 

each day to silica at 0.1 mg/m3 for one 

hour, at 0.075 mg/m3 for four hours and 

not exposed to silica for three hours. 

The cumulative exposure metric thus 

reflects a worker’s long-term average 

exposure without regard to the pattern 

of exposure experienced by the worker, 

and is therefore generally applicable to 

all workers who are exposed to silica in 

the various industries. For example, at 

construction sites, conditions may 

change often since the nature of work 

can be intermittent and involve working 

with a variety of materials that contain 

different concentrations of quartz. 

Additionally, workers may perform 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56320 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

construction operations for relatively 

short periods of time where they are 

exposed to concentrations of silica that 

may be significantly higher than many 

continuous operations in general 

industry. However, these differences are 

taken into account by the use of the 

cumulative exposure metric that relates 

exposure to disease risk. OSHA believes 

that use of cumulative exposure is the 

most appropriate dose-metric because 

each of the studies that provide the 

basis for the risk assessment 

demonstrated strong exposure-response 

relationships between cumulative 

exposure and disease risk. This metric 

is especially important in terms of 

progression of silica-related disease, as 

discussed in Section VII of the 

preamble, Significance of Risk, in 

section B.1.a. 

OSHA’s risk assessment relied upon 

many studies that utilized cumulative 

exposures of cohort members. Table VI– 

3 summarizes these lung cancer studies, 

including worker exposure quartile data 

across a number of industry sectors. The 

cumulative exposures exhibited in these 

studies are equivalent to the cumulative 

exposure that would result from 45 

years of exposure to the current and 

proposed PELs (i.e., 4.5 and 2,25 mg/m3, 

respectively). For this reason, OSHA has 

a high degree of confidence in the risk 

estimates associated with exposure to 

the current and proposed PELs; 

additionally, the risk assessment does 

not require significant low-dose 

extrapolation of the model beyond the 

observed range of exposures. OSHA 

acknowledges there is greater 

uncertainty in the risk estimates for the 

proposed action level of 0.025 mg/m3, 

particularly given some evidence of a 

threshold for silicosis between the 

proposed PEL and action level. Given 

the Agency’s findings that controlling 

exposures below the proposed PEL 

would not be technologically feasible 

for employers, OSHA believes that 

estimating risk for exposures below the 

proposed action level, which becomes 

increasingly more uncertain, is not 

necessary to further inform the Agency’s 

regulatory action. 

Although the Agency believes that the 

results of its risk assessment are broadly 

relevant to all occupational exposure 

situations involving crystalline silica, 

OSHA acknowledges that differences 

exist in the relative toxicity of 

crystalline silica particles present in 

different work settings due to factors 

such as the presence of mineral or metal 

impurities on quartz particle surfaces, 

whether the particles have been freshly 

fractured or are aged, and size 

distribution of particles. At this time, 

however, OSHA preliminarily 

concludes that it is not yet possible to 

use available information on factors that 

mediate the potency of silica to refine 

available quantitative estimates of the 

lung cancer and silicosis mortality risks, 

and that the estimates from the studies 

and analyses relied upon are fairly 

representative of a wide range of 

workplaces reflecting differences in 

silica polymorphism, surface properties, 

and impurities. 

TABLE VI–1—ESTIMATES OF LIFETIME A LUNG CANCER MORTALITY RISK RESULTING FROM 45-YEARS OF EXPOSURE TO

CRYSTALLINE SILICA

[Deaths per 1,000 workers (95% confidence interval)] 

Cohort Model 

Exposure 

lag 

(years) 

Model parameters 

(standard error) 

Exposure level (mg/m3) 

0.025 0.05 0.10 0.25 0.50 

Ten pooled cohorts 

(see Table II–1).

Log-linear b ............ 15 b = 0.60 (0.015) .... 22 (11–36) 26 (12–41) 29 (13–48) 34 (15–56) 38 (17–63) 

Linear b .................. 15 b = 0.074950 

(0.024121).

23 (9–38) 26 (10–43) 29 (11–47) 33 (12–53) 36 (14–58) 

Linear .................... 15 b1 = 0.16498 

(0.0653) and.

9 (2–16) 18 (4–31) 22 (6–38) 27 (12–43) 36 (20–51) 

Spline§c d ............... b2 = ¥0.1493 

(0.0657).

Range from 10 cohorts............................ 15 Various .................. 0.21–13 0.41–28 0.83–69 2.1–298 4.2–687 

Log-linear c ............

Diatomaceous 

earth workers.

Linear c .................. 10 b = 0.1441 e ........... 9 (2–21) 17 (5–41) 34 (10–79) 81 (24–180) 152 (46–312) 

U.S.Granite workers.Log-linear c ............ 15 b = 0.19 e ............... 11 (4–18) 25 (9–42) 60 (19–111) 250 (59–502) 653 (167–760) 

North American industrial sand 

workers.

Log-linear c ............ 15 b = 0.13 (0.074)f ... 7 (0–16) 15 (0–37) 34 (0–93) 120 (0–425) 387 (0–750) 

British coal miners Log-linear c ............ 15 B = 0.0524 

(0.0188).

3 (1–5) 6 (2–11) 13 (4–23) 37 (9–75) 95 (20–224) 

a Risk to age 85 and based on 2006 background mortality rates for all males (see Appendix for life table method). b Model with log cumulative exposure (mg/m3-days + 1). c Model with cumulative exposure (mg/m3-years). d 95% confidence interval calculated as follows (where CE = cumulative exposure in mg/m3-years and SE is standard error of the parameter estimate): 

For CE ≤ 2.19: 1 + [(b1 ± (1.96*SE1)) * CE]. 

For CE > 2.19: 1 + [(b1 * CE) + (b2 * (CE–2.19))] ± 1.96 * SQRT[ (CE2 * SE1

2) + ((CE–2.19)2* SE22) + (2*CE*(CE–3.29)*-0.00429)]. eStandard error not reported, upper and lower confidence limit on beta estimated from confidence interval of risk estimate reported in original article. 

fStandard error of the coefficient was estimated from the p-value for trend. 

TABLE VI–2—SUMMARY OF LIFETIME OR CUMULATIVE RISK ESTIMATES FOR CRYSTALLINE SILICA

Health endpoint (source) 

Risk associated with 45 years of occupational exposure 

(per 1,000 workers) 

Respirable crystalline silica exposure level (mg/m3) 

0.025 0.05 0.100 0.250 0.500 

Lung Cancer Mortality (Lifetime Risk): 

Pooled Analysis, Toxichemica, Inc (2004) a b ............... 9–23 18–26 22–29 27–34 36–38 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56321 

TABLE VI–2—SUMMARY OF LIFETIME OR CUMULATIVE RISK ESTIMATES FOR CRYSTALLINE SILICA—Continued 

Health endpoint (source) 

Risk associated with 45 years of occupational exposure 

(per 1,000 workers) 

Respirable crystalline silica exposure level (mg/m3) 

0.025 0.05 0.100 0.250 0.500 

Diatomaceous Earth Worker study (Rice et al., 

2001) a c ..................................................................... 9 17 34 81 152 

U.S. Granite Worker study (Attfield and Costello, 

2004) a d ..................................................................... 11 25 60 250 653 

North American Industrial Sand Worker study 

(Hughes et al., 2001) a e ............................................ 7 15 34 120 387 

British Coal Miner study (Miller and MacCalman, 

2009) a f ...................................................................... 3 6 13 37 95 

Silicosis and Non-Malignant Lung Disease Mortality 

(Lifetime Risk): 

Pooled Analysis (Toxichemica, Inc., 2004) (silicosis) g 4 7 11 17 22 

Diatomaceous Earth Worker study (Park et al., 2002) 

(NMRD) h ................................................................... 22 43 83 188 321 

Renal Disease Mortality (Lifetime Risk): 

Pooled Cohort study (Steenland et al., 2002a) ............ 25 32 39 52 63 

Silicosis Morbidity (Cumulative Risk): 

Chest x-ray category of 2/1 or greater (Buchanan et 

al., 2003)j .................................................................. 21 55 301 994 1000 

Silicosis mortality and/or x-ray of 1/1 or greater 

(Steenland and Brown, 1995b) k ............................... 31 74 431 593 626 

Chest x-ray category of 1/1 or greater (Hnizdo and 

Sluis-Cremer, 1993)l ................................................. 6 127 773 995 1000 

Chest x-ray category of 1 or greater (Chen et al., 

2001) m ...................................................................... 40 170 590 1000 1000 

Chest x-ray category of 1 or greater (Chen et al., 

2005) n

Tin miners .............................................................. 40 100 400 950 1000 

Tungsten miners .................................................... 5 20 120 750 1000 

Pottery workers ...................................................... 5 20 60 300 700 

From Table II–12, ‘‘Respirable Crystalline Silica—Health Effects Literature Review and Preliminary Quantitative Risk Assessment’’ 

(Docket OSHA–2010–0034). 

TABLE VI–3—EXPOSURE DISTRIBUTION IN LUNG CANCER STUDIES

Study n 

Primary 

exposure 

(as 

described 

in study) 

No. of 

deaths 

from lung 

cancer 

Cum(exp) (mg/m3-y) Average* exposure (mg/m3) Mean respirable 

crystalline 

silica exposure 

over employment 

period 

(mg/m∧3) 

q1 median 

(q2) q3 max 25th (q1) median (q2) 75th (q3) max 

U.S. diatomaceous earth 

workers 1

(Checkoway 

et al., 1997).

2,342 cristobalite 77 0.37 1.05 2.48 62.52 0.11 0.18 0.46 2.43 n/a 

S. African gold 

miners 1

(Hnizdo and 

Sluis-cremer, 

1991 & 

Hnizdo et al., 

1997).

2,260 quartz and 

other silicates.

77 n/a 4.23 n/a n/a 0.15 0.19 0.22 0.31 n/a 

U.S. gold miners 1

(Steenland 

and Brown, 

1995a).

3,328 silica dust 156 0.1 0.23 0.74 6.2 0.02 0.05 0.1 0.24 n/a 

Australian gold 

miners 1 (de 

Klerk and 

Musk, 1998).

2,297 silica dust 135 6.52 11.37 17.31 50.22 0.25 0.43 0.65 1.55 n/a 

U.S. granite 

workers 

(Costello and 

Graham, 

1988).

5,414 silica dust 

from 

granite.

124 0.14 0.71 2.19 50 0.02 0.05 0.08 1.01 n/a 

Finnish granite 

workers 

(Koskela et 

al., 1994).

1,026 quartz dust 38 0.84 4.63 15.42 100.98 0.39 0.59 1.29 3.6 n/a 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56322 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VI–3—EXPOSURE DISTRIBUTION IN LUNG CANCER STUDIES—Continued 

Study n 

Primary 

exposure 

(as 

described 

in study) 

No. of 

deaths 

from lung 

cancer 

Cum(exp) (mg/m3-y) Average* exposure (mg/m3) Mean respirable 

crystalline 

silica exposure 

over employment 

period 

(mg/m∧3) 

q1 median 

(q2) q3 max 25th (q1) median 

(q2) 75th (q3) max 

U.S. industrial 

sand workers 1

(Steenland 

et al., 2001b).

4,626 silica dust 85 0.03 0.13 5.2 8.265 0.02 0.04 0.06 0.4 n/a 

North American industrial sand 

workers 1

(Hughes et 

al., 2001).

90 crystalline 

silica.

95 1.11 2.73 5.20 n/a 0.069 0.15 0.025 n/a n/a 

Ch. Tungsten 

(Chen et al., 

1992).

28,442 silica dust 174 3.49 8.56 29.79 232.26 0.15 0.32 1.28 4.98 6.1 

Ch. Pottery 

(Chen et al., 

1992).

13,719 silica dust 81 3.89 6.07 9.44 63.15 0.18 0.22 0.34 2.1 11.4 

Ch. Tin (Chen 

et al., 1992).

7,849 silica dust 119 2.79 5.27 5.29 83.09 0.12 0.19 0.49 1.95 7.7 

British coal 

workers 1

(Miller and 

MacCalman, 

2009).

17,820 quartz ....... 973 n/a n/a n/a n/a n/a n/a n/a n/a n/a 

1Study adjusted for effects smoking. 

* Average exposure is cumulative exposure averaged over the entire exposure period. 

n/a Data not available. 

VII. Significance of Risk 

A. Legal Requirements 

To promulgate a standard that 

regulates workplace exposure to toxic 

materials or harmful physical agents, 

OSHA must first determine that the 

standard reduces a ‘‘significant risk’’ of 

‘‘material impairment.’’ The first part of 

this requirement, ‘‘significant risk,’’ 

refers to the likelihood of harm, whereas 

the second part, ‘‘material impairment,’’ 

refers to the severity of the 

consequences of exposure. 

The Agency’s burden to establish 

significant risk derives from the OSH 

Act, 29 U.S.C. 651 et seq. Section 3(8) 

of the Act requires that workplace safety 

and health standards be ‘‘reasonably 

necessary and appropriate to provide 

safe or healthful employment.’’ 29 

U.S.C. 652(8). The Supreme Court, in 

the ‘‘benzene’’ decision, stated that 

section 3(8) ‘‘implies that, before 

promulgating any standard, the 

Secretary must make a finding that the 

workplaces in question are not safe.’’ 

Indus. Union Dep’t, AFL–CIO v. Am. 

Petroleum Inst., 448 U.S. 607, 642 

(1980). Examining section 3(8) more 

closely, the Court described OSHA’s 

obligation to demonstrate significant 

risk: 

‘‘[S]afe’’ is not the equivalent of ‘‘risk-free.’’ 

A workplace can hardly be considered 

‘‘unsafe’’ unless it threatens the workers with 

a significant risk of harm. Therefore, before 

the Secretary can promulgate any permanent 

health or safety standard, he must make a 

threshold finding that the place of 

employment is unsafe in the sense that 

significant risks are present and can be 

eliminated or lessened by a change in 

practices. 

Id. While clarifying OSHA’s 

responsibilities, the Court emphasized 

the Agency’s discretion in determining 

what constitutes significant risk, stating, 

‘‘[the Agency’s] determination that a 

particular level of risk is ‘significant’ 

will be based largely on policy 

considerations.’’ Benzene, 448 U.S. at 

655, n. 62. The Court explained that 

significant risk is not a ‘‘mathematical 

straitjacket,’’ and maintained that OSHA 

could meet its burden without 

‘‘wait[ing] for deaths to occur before 

taking any action.’’ Benzene, 448 U.S. at 

655. 

Because section 6(b)(5) of the Act 

requires that the Agency base its 

findings on the ‘‘best available 

evidence,’’ a reviewing court must ‘‘give 

OSHA some leeway where its findings 

must be made on the frontiers of 

scientific knowledge.’’ Benzene, 448 

U.S. at 656. Thus, while OSHA’s 

significant risk determination must be 

supported by substantial evidence, the 

Agency ‘‘is not required to support the 

finding that a significant risk exists with 

anything approaching scientific 

certainty.’’ Id. Furthermore, ‘‘the 

Agency is free to use conservative 

assumptions in interpreting the data 

with respect to carcinogens, risking 

error on the side of over protection 

rather than under protection,’’ so long as 

such assumptions are based in ‘‘a body 

of reputable scientific thought.’’ Id. 

The Act also requires that the Agency 

make a finding that the toxic material or 

harmful physical agent at issue causes 

material impairment to workers’ health. 

Section 6(b)(5) of the Act directs the 

Secretary of Labor to ‘‘set the standard 

which most adequately assures, to the 

extent feasible, on the basis of the best 

available evidence, that no employee 

will suffer material impairment of 

health or functional capacity even if 

such employee has regular exposure to 

the hazard . . . for the period of his 

working life.’’ 29 U.S.C. 655(b)(5). As 

with significant risk, what constitutes 

material impairment in any given case 

is a policy determination for which 

OSHA is given substantial leeway. 

‘‘OSHA is not required to state with 

scientific certainty or precision the 

exact point at which each type of [harm] 

becomes a material impairment.’’ AFL– 

CIO v. OSHA, 965 F.2d 962, 975 (11th 

Cir. 1992). Courts have also noted that 

OSHA should consider all forms and 

degrees of material impairment—not 

just death or serious physical harm— 

and that OSHA may act with a 

‘‘pronounced bias towards worker 

safety.’’ Id; Bldg & Constr. Trades Dep’t 

v. Brock, 838 F.2d 1258, 1266 (D.C. Cir. 

1988). 

It is the Agency’s practice to estimate 

risk to workers by using quantitative 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56323 

risk assessment and determining the 

significance of that risk based on 

judicial guidance, the language of the 

OSH Act, and Agency policy 

considerations. Thus, using the best 

available evidence, OSHA identifies 

material health impairments associated 

with potentially hazardous occupational 

exposures, and, when possible, provides 

a quantitative assessment of exposed 

workers’ risk of these impairments. The 

Agency then evaluates whether these 

risks are severe enough to warrant 

regulatory action and determines 

whether a new or revised rule will 

substantially reduce these risks. 

In this case, OSHA has reviewed 

extensive toxicological, 

epidemiological, and experimental 

research pertaining to adverse health 

effects of occupational exposure to 

respirable crystalline silica, including 

silicosis, other non-malignant 

respiratory disease, lung cancer, and 

autoimmune and renal diseases. As a 

result of this review, the Agency has 

developed preliminary quantitative 

estimates of the excess risk of mortality 

and morbidity that is attributable to 

currently allowable respirable 

crystalline silica exposure 

concentrations. The Agency is 

proposing a new PEL of 0.05 mg/m3

because exposures at and above this 

level present a significant risk to 

workers’ health. Even though OSHA’s 

preliminary risk assessment indicates 

that a significant risk exists at the 

proposed action level of 0.025 mg/m3, 

the Agency is not proposing a PEL 

below the proposed 0.05 mg/m3 limit 

because OSHA must also consider 

technological and economic feasibility 

in determining exposure limits. As 

explained in the Summary and 

Explanation for paragraph (c), 

Permissible Exposure Limit (PEL), 

OSHA has preliminary determined that 

the proposed PEL of 0.05 mg/m3 is 

technologically and economically 

feasible, but that a lower PEL of 0.025 

mg/m3 is not technologically feasible. 

OSHA has preliminarily determined 

that long-term exposure at the current 

PEL presents a significant risk of 

material harm to workers’ health, and 

that adoption of the proposed PEL will 

substantially reduce this risk to the 

extent feasible. 

As discussed in Section V of this 

preamble (Health Effects Summary), 

inhalation exposure to respirable 

crystalline silica increases the risk of a 

variety of adverse health effects, 

including silicosis, chronic obstructive 

pulmonary disease (COPD), lung cancer, 

immunological effects, kidney disease, 

and infectious tuberculosis (TB). OSHA 

considers each of these conditions to be 

a material impairment of health. These 

diseases result in significant discomfort, 

permanent functional limitations 

including permanent disability or 

reduced ability to work, reduced quality 

of life, and decreased life expectancy. 

When these diseases coexist, as is 

common, the effects are particularly 

debilitating (Rice and Stayner, 1995; 

Rosenman et al., 1999). Based on these 

findings and on the scientific evidence 

that respirable crystalline silica 

substantially increases the risk of each 

of these conditions, OSHA preliminarily 

concludes that workers who are exposed 

to respirable crystalline silica at the 

current PEL are at significant risk of 

material impairment of health or 

functional capacity. 

B. OSHA’s Preliminary Findings 

1. Material Impairments of Health 

Section I of OSHA’s Health Effects 

Literature Review and Preliminary 

Quantitative Risk Assessment (available 

in Docket OSHA–2010–0034) describes 

in detail the adverse health conditions 

that workers who are exposed to 

respirable crystalline silica are at risk of 

developing. The Agency’s findings are 

summarized in Section V of this 

preamble (Health Effects Summary). The 

adverse health effects discussed include 

lung cancer, silicosis, other nonmalignant respiratory disease (NMRD), 

and immunological and renal effects. 

a. Silicosis 

Silicosis refers to a spectrum of lung 

diseases attributable to the inhalation of 

respirable crystalline silica. As 

described in Section V (Health Effects 

Summary), the three types of silicosis 

are acute, accelerated, and chronic. 

Acute silicosis can occur within a few 

weeks to months after inhalation 

exposure to extremely high levels of 

respirable crystalline silica. Death from 

acute silicosis can occur within months 

to a few years of disease onset, with the 

exposed person drowning in their own 

lung fluid (NIOSH, 1996). Accelerated 

silicosis results from exposure to high 

levels of airborne respirable crystalline 

silica, and disease usually occurs within 

5 to 10 years of initial exposure (NIOSH, 

1996). Both acute and accelerated 

silicosis are associated with exposures 

that are substantially above the current 

general industry PEL, although precise 

information on the relationships 

between exposure and occurrence of 

disease are not available. 

Chronic silicosis is the most common 

form of silicosis seen today, and is a 

progressive and irreversible condition 

characterized as a diffuse nodular 

pulmonary fibrosis (NIOSH, 1996). 

Chronic silicosis generally occurs after 

10 years or more of inhalation exposure 

to respirable crystalline silica at levels 

below those associated with acute and 

accelerated silicosis. Affected workers 

may have a dry chronic cough, sputum 

production, shortness of breath, and 

reduced pulmonary function. These 

symptoms result from airway restriction 

caused by the development of fibrotic 

scarring in the alveolar sacs and the 

ends of the lung tissue. The scarring can 

be detected in chest x-ray films when 

the lesions become large enough to 

appear as visible opacities. The result is 

restriction of lung volumes and 

decreased pulmonary compliance with 

concomitant reduced gas transfer 

(Balaan and Banks, 1992). Chronic 

silicosis is characterized by small, 

rounded opacities that are 

symmetrically distributed in the upper 

lung zones on chest radiograph. 

The diagnosis of silicosis is based on 

a history of exposure to respirable 

crystalline silica, chest radiograph 

findings, and the exclusion of other 

conditions, including tuberculosis (TB). 

Because workers affected by early stages 

of chronic silicosis are often 

asymptomatic, the finding of opacities 

in the lung is key to detecting silicosis 

and characterizing its severity. The 

International Labour Organization (ILO) 

International Classification of 

Radiographs of Pneumoconioses (ILO, 

1980, 2002, 2011) is the currently 

accepted standard against which chest 

radiographs are evaluated in 

epidemiologic studies, for medical 

surveillance, and for clinical evaluation. 

The ILO system standardizes the 

description of chest x-rays, and is based 

on a 12-step scale of severity and extent 

of silicosis as evidenced by the size, 

shape, and density of opacities seen on 

the x-ray film. Profusion (frequency) of 

small opacities is classified on a 4-point 

major category scale (0–3), with each 

major category divided into three, giving 

a 12-point scale between 0/¥ and 3/+. 

Large opacities are defined as any 

opacity greater than 1 cm that is present 

in a film. 

The small rounded opacities seen in 

early stage chronic silicosis (i.e., ILO 

major category 1 profusion) may 

progress (through ILO major categories 2 

and/or 3) and develop into large fibrotic 

masses that destroy the lung 

architecture, resulting in progressive 

massive fibrosis (PMF). This stage of 

advanced silicosis is usually 

characterized by impaired pulmonary 

function, disability, and premature 

death. In cases involving PMF, death is 

commonly attributable to progressive 

respiratory insufficiency (Balaan and 

Banks, 1992). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56324 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

The appearance of ILO category 2 or 

3 background profusion of small 

opacities has been shown to increase the 

risk of developing large opacities 

characteristic of PMF. In one study of 

silicosis patients in Hong Kong, Ng and 

Chan (1991) found the risk of PMF 

increased by 42 and 64 percent among 

patients whose chest x-ray films were 

classified as ILO major category 2 or 3, 

respectively. Research has shown that 

people with silicosis advanced beyond 

ILO major category 1 have reduced 

median survival times compared to the 

general population (Infante-Rivard et al., 

1991; Ng et al., 1992a; Westerholm, 

1980). 

Silicosis is the oldest known 

occupational lung disease and is still 

today the cause of significant premature 

mortality. In 2005, there were 161 

deaths in the U.S. where silicosis was 

recorded as an underlying or 

contributing cause of death on a death 

certificate (NIOSH, 2008c). Between 

1996 and 2005, deaths attributed to 

silicosis resulted in an average of 11.6 

years of life lost by affected workers 

(NIOSH, 2007). In addition, exposure to 

respirable crystalline silica remains an 

important cause of morbidity and 

hospitalizations. State-based hospital 

discharge data show that in the year 

2000, 1,128 silicosis-related 

hospitalizations occurred, indicating 

that silicosis continues to be a 

significant health issue in the U.S. 

(CSTE, 2005). Although there is no 

national silicosis disease surveillance 

system in the U.S., a published analysis 

of state-based surveillance data from the 

time period 1987–1996 estimated that 

between 3,600–7,000 new cases of 

silicosis occurred in the U.S. each year 

(Rosenman et al., 2003). It has been 

widely reported that available statistics 

on silicosis-related mortality and 

morbidity are likely to be understated 

due to misclassification of causes of 

death (for example, as tuberculosis, 

chronic bronchitis, emphysema, or cor 

pulmonale), errors in recording 

occupation on death certificates, or 

misdiagnosis of disease by health care 

providers (Goodwin, 2003; Windau et 

al., 1991; Rosenman et al., 2003). 

Furthermore, reliance on chest x-ray 

findings may miss cases of silicosis 

because fibrotic changes in the lung may 

not be visible on chest radiograph; thus, 

silicosis may be present absent x-ray 

signs or may be more severe than 

indicated by x-ray (Hnizdo et al., 1993; 

Craighead and Vallyathan, 1980; 

Rosenman et al., 1997). 

Although most workers with earlystage silicosis (ILO categories 0/1 or 1/ 

0) typically do not experience 

respiratory symptoms, the primary risk 

to the affected worker is progression of 

disease with progressive decline of lung 

function. Several studies of workers 

exposed to crystalline silica have shown 

that, once silicosis is detected by x-ray, 

a substantial proportion of affected 

workers can progress beyond ILO 

category 1 silicosis, even after exposure 

has ceased (for example, Hughes et al., 

1982; Hessel et al., 1988; Miller et al., 

1998; Ng et al., 1987a; Yang et al., 2006). 

In a population of coal miners whose 

last chest x-ray while employed was 

classified as major category 0, and who 

were examined again 10 years after the 

mine had closed, 20 percent had 

developed opacities consistent with a 

classification of at least 1/0, and 4 

percent progressed further to at least 2/ 

1 (Miller et al., 1998). Although there 

were periods of extremely high 

exposure to respirable quartz in the 

mine (greater than 2 mg/m3 in some jobs 

between 1972 and 1976, and more than 

10 percent of exposures between 1969 

and 1977 were greater than 1 mg/m3), 

the mean cumulative exposure for the 

cohort over the period 1964–1978 was 

1.8 mg/m3-years, corresponding to an 

average silica concentration of 0.12 mg/ 

m3. In a population of granite quarry 

workers exposed to an average 

respirable silica concentration of 0.48 

mg/m3 (mean length of employment was 

23.4 years), 45 percent of those 

diagnosed with simple silicosis showed 

radiological progression of disease after 

2 to 10 years of follow up (Ng et al., 

1987a). Among a population of gold 

miners, 92 percent progressed in 14 

years; exposures of high-, medium-, and 

low-exposure groups were 0.97, 0.45, 

and 0.24 mg/m3, respectively (Hessel et 

al., 1988). Chinese mine and factory 

workers categorized under the Chinese 

system of x-ray classification as 

‘‘suspected’’ silicosis cases (analogous 

to ILO 0/1) had a progression rate to 

stage I (analogous to ILO major category 

1) of 48.7 percent and the average 

interval was about 5.1 years (Yang et al., 

2006). These and other studies 

discussed in the Health Effects section 

are of populations of workers exposed to 

average concentrations of respirable 

crystalline silica above those permitted 

by OSHA’s current general industry 

PEL. The studies, however, are of 

interest to OSHA because the Agency’s 

current enforcement data indicate that 

exposures in this range are still common 

in some industry sectors. Furthermore, 

the Agency’s preliminary risk 

assessment is based on use of an 

exposure metric that is less influenced 

by exposure pattern and, instead, 

characterizes the accumulated exposure 

of workers over time. Further, the use of 

a cumulative exposure metric reflects 

the progression of silica-related 

diseases: While it is not known that 

silicosis is a precursor to lung cancer, 

continued exposure to respirable 

crystalline silica among workers with 

silicosis has been shown to be 

associated with malignant respiratory 

disease (Chen et al., 1992). The Chinese 

pottery workers study offers an example 

of silicosis-associated lung cancer 

among workers in the clay industry, 

reflecting the variety of health outcomes 

associated with diverse silica exposures 

across industrial settings. 

The risk of silicosis, and particularly 

its progression, carries with it an 

increased risk of reduced lung function. 

There is strong evidence in the literature 

for the finding that lung function 

deteriorates more rapidly in workers 

exposed to silica, especially those with 

silicosis, than what is expected from a 

normal aging process (Cowie 1998; 

Hughes et al., 1982; Malmberg et al., 

1993; Ng and Chan, 1992). The rates of 

decline in lung function are greater in 

those whose disease showed evidence of 

radiologic progression (Be ́gin et al., 

1987a; Cowie 1998; Ng and Chan, 1992; 

Ng et al., 1987a). Additionally, the 

average deterioration of lung function 

exceeds that in smokers (Hughes et al., 

1982). 

Several studies have reported no 

decrease in pulmonary function with an 

ILO category 1 level of profusion of 

small opacities but found declines in 

pulmonary function with categories 2 

and 3 (Ng et al., 1987a; Begin et al., 

1988; Moore et al., 1988). A study by 

Cowie (1998), however, found a 

statistically significantly greater annual 

loss in FVC and FEV1 among those with 

category 1 profusion compared to 

category 0. In another study, Cowie and 

Mabena (1991) found that the degree of 

profusion of opacities was associated 

with reductions in several pulmonary 

function metrics. Still, other studies 

have reported no associations between 

radiographic silicosis and decreases in 

pulmonary function (Ng et al., 1987a; 

Wiles et al., 1992; Hnizdo, 1992), with 

some studies (Ng et al., 1987a; Wang et 

al., 1997) finding that measurable 

changes in pulmonary function are 

evident well before the changes seen on 

chest x-ray. This may reflect the general 

insensitivity of chest radiography in 

detecting lung fibrosis, and/or may 

reflect that exposure to respirable silica 

has also been shown to increase the risk 

of chronic obstructive pulmonary 

disease (COPD) (see Section V, Health 

Effects Summary). 

Finally, silicosis, and exposure to 

respirable crystalline silica in and of 

itself, increases the risk that latent 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56325 

tuberculosis infection can convert to 

active disease. Early descriptions of dust 

diseases of the lung did not distinguish 

between TB and silicosis, and most fatal 

cases described in the first half of this 

century were a combination of silicosis 

and TB (Castranova et al., 1996). More 

recent findings demonstrate that 

exposure to silica, even without 

silicosis, increases the risk of infectious 

(i.e., active) pulmonary TB (Sherson et 

al., 1990; Cowie, 1994; Hnizdo and 

Murray, 1998; WaterNaude et al., 2006). 

Both conditions together can hasten the 

development of respiratory impairment 

and increase mortality risk even beyond 

that experienced by unexposed persons 

with active TB (Banks, 2005). 

Based on the information presented 

above and in its review of the health 

literature, OSHA preliminarily 

concludes that silicosis remains a 

significant cause of early mortality and 

of serious morbidity, despite the 

existence of an enforceable exposure 

limit over the past 40 years. Silicosis in 

its later stages of progression (i.e., with 

chest x-ray findings of ILO category 2 or 

3 profusion of small opacities, or the 

presence of large opacities) is 

characterized by the likely appearance 

of respiratory symptoms and decreased 

pulmonary function, as well as 

increased risk of progression to PMF, 

disability, and early mortality. Earlystage silicosis, although without 

symptoms among many who are 

affected, nevertheless reflects the 

formation of fibrotic lesions in the lung 

and increases the risk of progression to 

later stages, even after exposure to 

respirable crystalline silica ceases. In 

addition, the presence of silicosis 

increases the risk of pulmonary 

infections, including conversion of 

latent TB infection to active TB. 

Silicosis is not a reversible condition 

and there is no specific treatment for the 

disease, other than administration of 

drugs to alleviate inflammation and 

maintain open airways, or 

administration of oxygen therapy in 

severe cases. Based on these 

considerations, OSHA preliminarily 

finds that silicosis of any form, and at 

any stage, is a material impairment of 

health and that fibrotic scarring of the 

lungs represents loss of functional 

respiratory capacity. 

b. Lung Cancer 

OSHA considers lung cancer, an 

irreversible and usually fatal disease, to 

be a clear material impairment of health. 

According to the National Cancer 

Institute (Horner et al., 2009), the fiveyear survival rate for all forms of lung 

cancer is only 15.6 percent, a rate that 

has not improved in nearly two decades. 

OSHA’s preliminary finding that 

respirable crystalline silica exposure 

substantially increases the risk of lung 

cancer mortality is based on the best 

available toxicological and 

epidemiological data, reflects 

substantial supportive evidence from 

animal and mechanistic research, and is 

consistent with the conclusions of other 

government and public health 

organizations, including the 

International Agency for Research on 

Cancer (IARC, 1997), the National 

Toxicology Program (NTP, 2000), the 

National Institute for Occupational 

Safety and Health (NIOSH, 2002), the 

American Thoracic Society (1997), and 

the American Conference of 

Governmental Industrial Hygienists 

(ACGIH, 2001). The Agency’s primary 

evidence comes from evaluation of more 

than 50 studies of occupational cohorts 

from many different industry sectors in 

which exposure to respirable crystalline 

silica occurs, including granite and 

stone quarrying; the refractory brick 

industry; gold, tin, and tungsten mining; 

the diatomaceous earth industry; the 

industrial sand industry; and 

construction. Studies key to OSHA’s 

risk assessment are outlined in Table 

VII–1, which summarizes exposure 

characterization and related lung cancer 

risk across several different industries. 

In addition, the association between 

exposure to respirable crystalline silica 

and lung cancer risk was reported in a 

national mortality surveillance study 

(Calvert et al., 2003) and in two 

community-based studies (Pukkala et 

al., 2005; Cassidy et al., 2007), as well 

as in a pooled analysis of 10 

occupational cohort studies (Steenland 

et al., 2001a). 

TABLE VII–1— SUMMARY OF KEY LUNG CANCER STUDIES

Industry sector/population Type of study and description of population Exposure characterization No. of lung cancer 

deaths/cases Risk ratios (95% CI) Additional information Source 

U.S. Diatomaceous 

earth workers.

Cohort study. Same as 

Checkoway et al., 

1993, excluding 317 

workers whose exposures could not 

be characterized, 

and including 89 

workers with asbestos exposure who 

were previously excluded from the 

1993 study. Follow 

up through 1994.

Assessment based on 

almost 6,400 samples taken from 

1948–1988; about 

57 percent of samples represented 

particle counts, 17 

percent were personal respirable dust 

samples. JEM included 135 jobs 

over 4 time periods 

(Seixas et al., 1997).

77 ................................ SMR 129 (CI 101– 

161) based on national rates, and 

SMR 144 (CI 114– 

180) based on local 

rates. Risk ratios by 

exposure quintile 

were 1.00, 0.96, 

0.77, 1.26, and 2.15, 

with the latter being 

stat. sig. RR= 2.15 

and 1.67.

Smoking history available for half cohort. 

Under worst-case 

assumptions, the 

risk ratio for the 

high-exposure group 

would be reduced to 

1.67 after accounting for smoking.

Checkoway et al., 

1997. 

South African 

gold miners.

Cohort study. N=2,209 

white male miners 

employed between 

1936 and 1943. Followed from 1968– 

1986.

Particle count data 

from Beadle (1971).

77 ................................ RR 1.023 (CI 1.005– 

1.042) per 1,000 

particle-years of exposure based on 

Cox proportional 

hazards model.

Model adjusted for 

smoking and year of 

birth. Lung cancer 

was associated with 

silicosis of the hilar 

glands not silicosis 

of lung or pleura. 

Possible confounding by radon 

exposure among 

miners with 20 or 

more years experience.

Hnizdo and SluisCremer, 1991. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56326 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VII–1— SUMMARY OF KEY LUNG CANCER STUDIES—Continued 

Industry sector/population Type of study and description of population Exposure characterization No. of lung cancer 

deaths/cases Risk ratios (95% CI) Additional information Source 

South African 

gold miners.

Nested case-control 

study from population study by 

Hnizdo and SluisCremer,1991. N=78 

cases, 386 controls.

Particle count data 

converted to respirable dust mass 

(Beadle and Bradley, 1970, and 

Page-Shipp and 

Harris, 1972).

78 ................................ RR 2.45 (CI 1.2–5.2) 

when silicosis was 

included in model.

Lung cancer mortality 

associated with 

smoking, cumulative 

dust exposure, and 

duration of underground work. Latter 

two factors were 

most significantly 

associated with lung 

cancer with exposure lagged 20 

years.

Hnizdo et al., 1997. 

US gold miners.Cohort and nested 

case-control study, 

same population as 

Brown et al. (1986); 

workers with at least 

1 year underground 

work between 1940 

and 1965. Follow up 

through 1990.

Particle count data, 

conversion to mass 

concentration based 

on Vt. Granite study, 

construction of JEM. 

Median quartz exposures were 0.15, 

0.07, and 0.02 mg/

m3 prior to 1930, 

from 1930–1950, 

and after 1950 respectively.

115 .............................. SMR 113 (CI 94–136) 

overall. SMRs increased for workers 

with 30 or more 

years of latency, 

and when local cancer rates used as 

referents. Case-control study showed no 

relationship of risk to 

cumulative exposure 

to dust.

Smoking data available for part of cohort, habits comparable to general 

US population; attributable smokingrelated cancer risk 

estimated to be 1.07.

Steenland and Brown, 

1995a, 1995b 

Australian 

gold miners.

Cohort and nested 

case-control study. 

N=2,297, follow up 

of Armstrong et al. 

(1979). Follow up 

through 1993.

Expert ranking of 

dustiness by job.

Nested case control of 

138 lung cancer 

deaths.

SMR 126 (CI 107– 

159) lower bound; 

SMR 149 (CI 126– 

176) upper bound. 

From case-control, 

RR 1.31 (CI 1.10– 

1.7) per unit exposure score.

Association between 

exposure and lung 

cancer mortality not 

stat. sig. after adjusting for smoking, 

bronchitis, and silicosis. Authors concluded lung cancer 

restricted to miners 

who received compensation for silicosis..

de Klerk and Musk, 

1998 

U.S. 

(Vermont) 

granite 

shed and 

quarry 

workers –.

Cohort study. N=5,414 

employed at least 1 

year between 1950 

and 1982.

Exposure data not 

used in analysis.

53 deaths among 

those hired before 

1930; 43 deaths 

among those hired 

after 1940.

SMR 129 for pre-1930 

hires (not stat. sig.); 

SMR 95 for post1940 hires (not stat. 

sig). SMR 181 (stat. 

sig) for shed workers hired before 

1930 and with long 

tenure and latency.

Dust controls employed between 

1938 and 1940 with 

continuing improvement afterwards.

Costello and Graham, 

1988. 

Finnish granite workers.Cohort and nested 

case-control studies. 

N=1,026, follow up 

from 1972–1981, extended to 1985 

(Koskella et al., 

1990) and 1989 

(Koskella et al., 

1994).

Personal sampling 

data collected from 

1970–1972 included 

total and respirable 

dust and respirable 

silica sampling. Average silica concentrations ranged 

form 0.3–4.9 mg/m3.

31 through 1989 ......... Through 1989, SMR 

140 (CI 98–193). 

For workers in two 

regions where silica 

content of rock was 

highest, SMRs were 

126 (CI 71–208) and 

211 (CI 120–342), 

respectively.

Smoking habits similar 

to other Finnish occupational groups. 

Minimal work-related 

exposures to other 

carcinogens.

Koskela et al., 1987, 

1990, 1994. 

North American industrial sand 

workers.

Case-control study 

from McDonald et 

al. (2001) cohort.

Assessment based on 

14,249 respirable 

dust and silica samples taken from 

1974 to 1998. Exposures prior to this 

based on particle 

count data. Adjustments made for respirator use (Rando 

et al., 2001).

95 cases, two controls 

per case.

OR 1.00, 0.84, 2.02 

and 2.07 for increasing quartiles of exposure p for 

trend=0.04).

Adjusted for smoking. 

Positive association 

between silica exposure and lung cancer. Median exposure for cases and 

controls were 0.148 

and 0.110 mg/m3

respirable silica, respectively.

Hughes et al., 2001. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56327 

TABLE VII–1— SUMMARY OF KEY LUNG CANCER STUDIES—Continued 

Industry sector/population Type of study and description of population Exposure characterization No. of lung cancer 

deaths/cases Risk ratios (95% CI) Additional information Source 

U.S. industrial sand 

workers.

Cohort and nested 

case-control study. 

N=4,626 workers. 

Follow up from 

1960–1996.

Exposure assessment 

based on 4,269 

compliance dust 

samples taken from 

1974–1996 and analyzed for respirable 

quartz. Exposures 

prior to 1974 based 

on particle count 

data and quartz 

analysis of settled 

dust and dust collected by high-volume air samplers, 

and use of a conversion factor (1 

mppcf=0.1 mg/m3).

109 deaths overall ...... SMR 160 (CI 131– 

193) overall. Positive trends seen with 

cumulative silica exposure (p=0.04 for 

unlagged, p=0.08 for 

lagged).

Smoking data from 

358 workers suggested that smoking 

could not explain the 

observed increase in 

lung cancer mortality 

rates.

Steenland and 

Sanderson, 2001. 

Chinese Tin, 

Tungsten, 

and Copper miners.

Cohort study. 

N=54,522 workers 

employed 1 yr. or 

more between 1972 

and 1974. Follow up 

through 1989.

Measurements for total 

dust, quartz content, 

and particle size 

taken from 1950’s1980’s. Exposures 

categorized as high, 

medium, low, or 

non-exposed.

..................................... SMRs 198 for tin 

workers (no CI reported but stat. sig.). 

No stat. sig. increased SMR for 

tungsten or copper 

miners.

Non-statistically significantly increased risk 

ratio for lung cancer 

among silicotics. No 

increased gradient 

in risk observed with 

exposure.

Chen et al., 1992. 

Chinese Pottery workers.Cohort study. 

N=13,719 workers 

employed in 1972– 

1974. Follow up 

through 1989.

Measurements of jobspecific total dust 

and quartz content 

of settled dust used 

to classify workers 

into one of four total 

dust exposure 

groups.

..................................... SMR 58 (p<0.05) overall. RR 1.63 (CI 0.8– 

3.4) among silicotics 

compared to nonsilicotics.

No reported increase 

in lung cancer with 

increasing exposure.

Chen et al., 1992. 

British Coal 

workers.

Cohort study. 

N=17,820 miners 

from 10 collieries..

Quartz exposure assessed from personal respirable dust 

samples.

973 .............................. Significant relationship 

between cumulative 

silica exposure 

(lagged 15 years) 

and lung cancer 

mortality VIA Cox 

regression.

Adjusted for smoking .. Miller et al, 2007; Miller and MacCalman, 

2009 

Toxicity studies provide additional 

evidence of the carcinogenic potential of 

crystalline silica (Health Effects 

Summary, Section V). Acellular studies 

using DNA exposed directly to freshly 

fractured crystalline silica demonstrate 

the direct effect silica has on DNA 

breakage. Cell culture research has 

investigated the processes by which 

crystalline silica disrupts normal gene 

expression and replication (Section V). 

Studies demonstrate that chronic 

inflammatory and fibrotic processes 

resulting in oxidative and cellular 

damage set up another possible 

mechanism that leads to neoplastic 

changes in the lung (Goldsmith, 1997; 

see also Health Effects discussion in 

Section V). In addition, the biologically 

damaging physical characteristics of 

crystalline silica, and the direct and 

indirect genotoxicity of crystalline silica 

(Schins, 2002; Borm and Driscoll, 1996), 

support the Agency’s preliminary 

position that respirable crystalline silica 

should be considered as an occupational 

carcinogen that causes lung cancer, a 

clear material impairment of health. 

c. Non-Malignant Respiratory Disease 

(Other Than Silicosis) 

Exposure to respirable crystalline 

silica increases the risk of developing 

chronic obstructive pulmonary disease 

(COPD), in particular chronic bronchitis 

and emphysema. COPD results in loss of 

pulmonary function that restricts 

normal activity in individuals afflicted 

with these conditions (ATS, 2003). Both 

chronic bronchitis and emphysema can 

occur in conjunction with development 

of silicosis. Several studies have 

documented increased prevalence of 

chronic bronchitis and emphysema 

among silica-exposed workers even 

absent evidence of silicosis (see Section 

I of the Health Effects Literature Review 

and Preliminary Quantitative Risk 

Assessment; NIOSH, 2002; ATS, 1997). 

There is evidence that smoking may 

have an additive or synergistic effect on 

silica-related COPD morbidity or 

mortality (Hnizdo, 1990; Hnizdo et al., 

1990; Wyndham et al., 1986; NIOSH, 

2002). In a study of diatomaceous earth 

workers, Park et al. (2002) found a 

positive exposure-response relationship 

between exposure to respirable 

cristobalite and increased mortality 

from non-malignant respiratory disease. 

Decrements in pulmonary function 

have often been found among workers 

exposed to respirable crystalline silica 

absent radiologic evidence of silicosis. 

Several cross-sectional studies have 

reported such findings among granite 

workers (Theriault, 1974a, 1974b; Ng et 

al., 1992b; Montes et al., 2004b), South 

African gold miners (Irwig and Rocks, 

1978; Hnizdo et al., 1990; Cowie and 

Mabena, 1991), gemstone cutters (Ng et 

al., 1987b), concrete workers (Meijer et 

al., 2001), refractory brick workers 

(Wang et al., 1997), hard rock miners 

(Manfreda et al., 1982; Kreiss et al., 

1989), pottery workers (Neukirch et al., 

1994), slate workers (Suhr et al., 2003), 

and potato sorters (Jorna et al., 1994). 

OSHA also evaluated several 

longitudinal studies where exposed 

workers were examined over a period of 

time to track changes in pulmonary 

function. Among both active and retired 

Vermont granite workers exposed to an 

average of 60 mg/m3, Graham did not 

find exposure-related decrements in 

pulmonary function (Graham et al., 

1981, 1994). However, Eisen et al. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56328 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

(1995) did find significant pulmonary 

decrements among a subset of granite 

workers (termed ‘‘dropouts’’) who left 

work and consequently did not 

voluntarily participate in the last of a 

series of annual pulmonary function 

tests. This group of workers experienced 

steeper declines in FEV1 compared to 

the subset of workers who remained at 

work and participated in all tests 

(termed ‘‘survivors’’), and these declines 

were significantly related to dust 

exposure. Thus, in this study, workers 

who had left work had exposure-related 

declines in pulmonary function to a 

greater extent than did workers who 

remained on the job, clearly 

demonstrating a survivor effect among 

the active workers. Exposure-related 

changes in lung function were also 

reported in a 12-year study of granite 

workers (Malmberg et al., 1993), in two 

5-year studies of South African miners 

(Hnizdo, 1992; Cowie, 1998), and in a 

study of foundry workers whose lung 

function was assessed between 1978 

and 1992 (Hertzberg et al., 2002). 

Each of these studies reported their 

findings in terms of rates of decline in 

any of several pulmonary function 

measures, such as FVC, FEV1, and FEV1/ 

FVC. To put these declines in 

perspective, Eisen et al. (1995), reported 

that the rate of decline in FEV1 seen 

among the dropout subgroup of 

Vermont granite workers was 4 ml per 

mg/m3-year of exposure to respirable 

granite dust; by comparison, FEV1

declines at a rate of 10 ml/year from 

smoking one pack of cigarettes daily. 

From their study of foundry workers, 

Hertzberg et al., (2002) reported finding 

a 1.1 ml/year decline in FEV1 and a 1.6 

ml/year decline in FVC for each mg/m3- 

year of respirable silica exposure after 

controlling for ethnicity and smoking. 

From these rates of decline, they 

estimated that exposure to the current 

OSHA quartz standard of 0.1 mg/m3 for 

40 years would result in a total loss of 

FEV1 and FVC that is less than but still 

comparable to smoking a pack of 

cigarettes daily for 40 years. Hertzberg et 

al. (2002) also estimated that exposure 

to the current standard for 40 years 

would increase the risk of developing 

abnormal FEV1 or FVC by factors of 1.68 

and 1.42, respectively. OSHA believes 

that this magnitude of reduced 

pulmonary function, as well as the 

increased morbidity and mortality from 

non-malignant respiratory disease that 

has been documented in the studies 

summarized above, constitute material 

impairments of health and loss of 

functional respiratory capacity. 

d. Renal and Autoimmune Effects 

OSHA’s review of the literature 

summarized in Section V, Health Effects 

Summary, reflects substantial evidence 

that exposure to crystalline silica 

increases the risk of renal and 

autoimmune diseases. Epidemiologic 

studies have found statistically 

significant associations between 

occupational exposure to silica dust and 

chronic renal disease (e.g., Calvert et al., 

1997), subclinical renal changes 

including proteinurea and elevated 

serum creatinine (e.g., Ng et al., 1992c; 

Rosenman et al., 2000; Hotz et al., 1995), 

end-stage renal disease morbidity (e.g., 

Steenland et al., 1990), chronic renal 

disease mortality (Steenland et al., 

2001b, 2002a), and Wegener’s 

granulomatosis (Nuyts et al., 1995), the 

latter of which represents severe injury 

to the glomeruli that, if untreated, 

rapidly leads to renal failure. Possible 

mechanisms suggested for silicainduced renal disease include a direct 

toxic effect on the kidney, deposition in 

the kidney of immune complexes (IgA) 

following silica-related pulmonary 

inflammation, or an autoimmune 

mechanism (Calvert et al., 1997; 

Gregorini et al., 1993). Steenland et al. 

(2002a) demonstrated a positive 

exposure-response relationship between 

exposure to respirable crystalline silica 

and end-stage renal disease mortality. 

In addition, there are a number of 

studies that show exposure to be related 

to increased risks of autoimmune 

disease, including scleroderma (e.g., 

Sluis-Cremer et al., 1985), rheumatoid 

arthritis (e.g. Klockars et al., 1987; 

Rosenman and Zhu, 1995), and systemic 

lupus erythematosus (e.g., Brown et al., 

1997). Scleroderma is a degenerative 

disorder that leads to over-production of 

collagen in connective tissue that can 

cause a wide variety of symptoms 

including skin discoloration and 

ulceration, joint pain, swelling and 

discomfort in the extremities, breathing 

problems, and digestive problems. 

Rheumatoid arthritis is characterized by 

joint pain and tenderness, fatigue, fever, 

and weight loss. Systemic lupus 

erythematosus is a chronic disease of 

connective tissue that can present a 

wide range of symptoms including skin 

rash, fever, malaise, joint pain, and, in 

many cases, anemia and iron deficiency. 

OSHA believes that chronic renal 

disease, end-stage renal disease 

mortality, Wegener’s granulomatosis, 

scleroderma, rheumatoid arthritis, and 

systemic lupus erythematosus clearly 

represent material impairments of 

health. 

2. Significance of Risk 

To evaluate the significance of the 

health risks that result from exposure to 

hazardous chemical agents, OSHA relies 

on toxicological, epidemiological, and 

experimental data, as well as statistical 

methods. The Agency uses these data 

and methods to characterize the risk of 

disease resulting from workers’ 

exposure to a given hazard over a 

working lifetime at levels of exposure 

reflecting both compliance with current 

standards and compliance with the new 

standard being proposed. In the case of 

crystalline silica, the current general 

industry, construction, and shipyard 

PELs are formulas that limit 8-hour 

TWA exposures to respirable dust; the 

limit on exposure decreases with 

increasing crystalline silica content of 

the dust. OSHA’s current general 

industry PEL for respirable quartz is 

expressed both in terms of a particle 

count as well as a gravimetric 

concentration, while the current 

construction and shipyard employment 

PELs for respirable quartz are only 

expressed in terms of a particle count 

formula. For general industry, the 

gravimetric formula PEL for quartz 

approaches 0.1 mg/m3 (100 mg/m3) of 

respirable crystalline silica when the 

quartz content of the dust is about 10 

percent or greater. For the construction 

and shipyard industries, the current PEL 

is a formula that is based on 

concentration of respirable particles in 

the air; on a mass concentration basis, 

it is believed by OSHA to lie within a 

range of between about 0.25 mg/m3 (250 

mg/m3) to 0.5 mg/m3 (500 mg/m3) 

expressed as respirable quartz (see 

Section VI). In general industry, the 

current PELs for cristobalite and 

tridymite are one-half the PEL for 

quartz. 

OSHA is proposing to revise the 

current PELs for general industry, 

construction, and shipyards to 0.05 mg/ 

m3 (50 mg/m3) of respirable crystalline 

silica. OSHA is also proposing an action 

level of 0.025 mg/m3 (25 mg/m3). In the 

Summary of the Preliminary 

Quantitative Risk Assessment (Section 

VI of the preamble), OSHA presents 

estimates of health risks associated with 

45 years of exposure to 0.025, 0.05, and 

0.1 mg/m3 respirable crystalline silica to 

represent the risks associated with 

exposure over a working lifetime to the 

proposed action level, proposed PEL, 

and current general industry PEL, 

respectively. OSHA also presents 

estimates associated with exposure to 

0.25 and 0.5 mg/m3 to represent a range 

of risks likely to be associated with 

exposure to the current construction 

and shipyard PELs. Risk estimates are 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56329 

presented for mortality due to lung 

cancer, silicosis and other nonmalignant lung disease, and end-stage 

renal disease, as well as silicosis 

morbidity. The preliminary findings 

from this assessment are summarized 

below. 

a. Summary of Excess Risk Estimates for 

Excess Lung Cancer Mortality 

For preliminary estimates of lung 

cancer risk from crystalline silica 

exposure, OSHA has relied upon studies 

of exposure-response relationships 

presented in a pooled analysis of 10 

cohort studies (Steenland, et al. 2001a; 

Toxichemica, Inc., 2004) as well as on 

individual studies of granite (Attfield 

and Costello, 2004), diatomaceous earth 

(Rice et al., 2001), and industrial sand 

(Hughes et al., 2001) worker cohorts, 

and a study of coal miners exposed to 

respirable quartz (Miller et al., 2007; 

Miller and MacCalman, 2009). OSHA 

believes these studies are suitable for 

use to quantitatively characterize health 

risks to exposed workers because (1) 

study populations were of sufficient size 

to provide adequate power to detect low 

levels of risk, (2) sufficient quantitative 

exposure data were available to 

characterize cumulative exposures of 

cohort members to respirable crystalline 

silica, (3) the studies either adjusted for 

or otherwise adequately addressed 

confounding factors such as smoking 

and exposure to other carcinogens, and 

(4) investigators developed quantitative 

assessments of exposure-response 

relationships using appropriate 

statistical models or otherwise provided 

sufficient information that permits 

OSHA to do so. Where investigators 

estimated excess lung cancer risks 

associated with exposure to the current 

PEL or NIOSH recommended exposure 

limit, OSHA provided these estimates in 

its Preliminary Quantitative Risk 

Assessment. However, OSHA 

implemented all risk models in its own 

life table analysis so that the use of 

background lung cancer rates and 

assumptions regarding length of 

exposure and lifetime were constant 

across each of the models, and so OSHA 

could estimate lung cancer risks 

associated with exposure to specific 

levels of silica of interest to the Agency. 

The Steenland et al. (2001a) study 

consisted of a pooled exposure-response 

analysis and risk assessment based on 

raw data obtained for ten cohorts of 

silica-exposed workers (65,980 workers, 

1,072 lung cancer deaths). The cohorts 

in this pooled analysis include U.S. gold 

miners (Steenland and Brown, 1995a), 

U.S. diatomaceous earth workers 

(Checkoway et al., 1997), Australian 

gold miners (deKlerk and Musk, 1998), 

Finnish granite workers (Koskela et al., 

1994), South African gold miners 

(Hnizdo et al., 1997), U.S. industrial 

sand employees (Steenland et al., 

2001b), Vermont granite workers 

(Costello and Graham, 1988), and 

Chinese pottery workers, tin miners, 

and tungsten miners (Chen et al., 1992). 

The investigators used a nested casecontrol design with cases and controls 

matched for race, sex, age (within five 

years) and study; 100 controls were 

matched for each case. An extensive 

exposure assessment for this pooled 

analysis was developed and published 

by Mannetje et al. (2002a). Exposure 

measurement data were available for all 

10 cohorts and included measurements 

of particle counts, total dust mass, 

respirable dust mass, and, for one 

cohort, respirable quartz. Cohortspecific conversion factors were used to 

estimate cumulative exposures to 

respirable crystalline silica. A casecontrol analysis of silicosis mortality 

(Mannetje et al., 2002b) showed a strong 

positive exposure-response trend, 

indicating that cumulative exposure 

estimates for the cohorts were not 

subject to random misclassification 

errors of such a magnitude so as to 

obscure observing an exposure-response 

relationship between silica and silicosis 

despite the variety of dust measurement 

metrics relied upon and the need to 

make assumptions to convert the data to 

a single exposure metric (i.e., mass 

concentration of respirable crystalline 

silica). In effect, the known relationship 

between exposure to respirable silica 

and silicosis served as a positive control 

to assess the validity of exposure 

estimates. Quantitative assessment of 

lung cancer risks were based on use of 

a log-linear model (log RR = bx, where 

x represents the exposure variable and 

b the coefficient to be estimated) with a 

15-year exposure lag providing the best 

fit. Models based on untransformed or 

log-transformed cumulative dose 

metrics provided an acceptable fit to the 

pooled data, with the model using 

untransformed cumulative dose 

providing a slightly better fit. However, 

there was substantial heterogeneity 

among the exposure-response 

coefficients derived from the individual 

cohorts when untransformed 

cumulative dose was used, which could 

result in one or a few of the cohorts 

unduly influencing the pooled 

exposure-response coefficient. For this 

reason, the authors preferred the use of 

log-transformed cumulative exposure in 

the model to derive the pooled 

coefficient since heterogeneity was 

substantially reduced. 

OSHA’s implementation of this model 

is based on a re-analysis conducted by 

Steenland and Bartow (Toxichemica, 

2004), which corrected small errors in 

the assignment of exposure estimates in 

the original analysis. In addition, 

subsequent to the Toxichemica report, 

and in response to suggestions made by 

external peer reviewers, Steenland and 

Bartow conducted additional analyses 

based on use of a linear relative risk 

model having the general form RR = 1 

+ bx, as well as a categorical analysis 

(personal communication, Steenland 

2010). The linear model was 

implemented with both untransformed 

and log-transformed cumulative 

exposure metrics, and was also 

implemented as a 2-piece spline model. 

The categorical analysis indicates 

that, for the pooled data set, lung cancer 

relative risks increase steeply at low 

exposures, after which the rate of 

increase in relative risk declines and the 

exposure-response curve becomes flat 

(see Figure II–2 of the Preliminary 

Quantitative Risk Assessment). Use of 

either the linear relative risk or loglinear relative risk model with 

untransformed cumulative exposure 

(with or without a 15-year lag) failed to 

capture this initial steep slope, resulting 

in an underestimate of the relative risk 

compared to that suggested by the 

categorical analysis. In contrast, use of 

log-transformed cumulative exposure 

with the linear or log-linear model, and 

use of the 2-piece linear spline model 

with untransformed exposure, better 

reflected the initial rise and subsequent 

leveling out of the exposure-response 

curve, with the spline model fitting 

somewhat better than either the linear 

or log-linear models (all models 

incorporated a 15-year exposure lag). Of 

the three models that best reflect the 

shape of the underlying exposureresponse curve suggested by the 

categorical analysis, there is no clear 

rationale to prefer one over the other. 

Use of log-transformed cumulative 

exposure in either the linear or loglinear models has the advantage of 

reducing heterogeneity among the 10 

pooled studies, lessening the likelihood 

that the pooled coefficient would be 

overtly influenced by outliers; however, 

use of a log-transformed exposure 

metric complicates comparing results 

with those from other risk analyses 

considered by OSHA that are based on 

untransformed exposure metrics. Since 

all three of these models yield 

comparable estimates of risk the choice 

of model is not critical for the purpose 

of assessing significance of the risk, and 

therefore OSHA believes that the risk 

estimates derived from the pooled study 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56330 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

are best represented as a range of 

estimates based on all three of these 

models. 

From these models, the estimated 

lung cancer risk associated with 45 

years of exposure to 0.1 mg/m3 (about 

equal to the current general industry 

PEL) is between 22 and 29 deaths per 

1,000 workers. The estimated risk 

associated with exposure to silica 

concentrations in the range of 0.25 and 

0.5 mg/m3 (about equal to the current 

construction and shipyard PELs) is 

between 27 and 38 deaths per 1,000. At 

the proposed PEL of 0.05 mg/m3, the 

estimated excess risk ranges from 18 to 

26 deaths per 1,000, and, at the 

proposed action level of 0.025 mg/m3, 

from 9 to 23 deaths per 1,000. 

As previously discussed, the 

exposure-response coefficients derived 

from each of the 10 cohorts exhibited 

significant heterogeneity; risk estimates 

based on the coefficients derived from 

the individual studies for 

untransformed cumulative exposure 

varied by almost two orders of 

magnitude, with estimated risks 

associated with exposure over a working 

lifetime to the current general industry 

PEL ranging from a low of 0.8 deaths per 

1,000 (from the Chinese pottery worker 

study) to a high of 69 deaths per 1,000 

(from the South African miner study). It 

is possible that the differences seen in 

the slopes of the exposure-response 

relationships reflect physical differences 

in the nature of crystalline silica 

particles generated in these workplaces 

and/or the presence of different 

substances on the crystal surfaces that 

could mitigate or enhance their toxicity 

(see Section V, Health Effects 

Summary). It may also be that exposure 

estimates for some cohorts were subject 

to systematic misclassification errors 

resulting in under- or over-estimation of 

exposures due to the use of assumptions 

and conversion factors that were 

necessary to estimate mass respirable 

crystalline silica concentrations from 

exposure samples analyzed as particle 

counts or total and respirable dust mass. 

OSHA believes that, given the wide 

range of risk estimates derived from 

these 10 studies, use of log-transformed 

cumulative exposure or the 2-piece 

spline model is a reasonable approach 

for deriving a single summary statistic 

that represents the lung cancer risk 

across the range of workplaces and 

exposure conditions represented by the 

studies. However, use of these 

approaches results in a non-linear 

exposure-response and suggests that the 

relative risk of silica-related lung cancer 

begins to attenuate at cumulative 

exposures in the range of those 

represented by the current PELs. 

Although such exposure-response 

relationships have been described for 

some carcinogens (for example, from 

metabolic saturation or a healthy worker 

survivor effect, see Staynor et al., 2003), 

OSHA is not aware of any specific 

evidence that would suggest that such a 

result is biologically plausible for silica, 

except perhaps the possibility that lung 

cancer risks increase more slowly with 

increasing exposure because of 

competing risks from other silica-related 

diseases. Attenuation of the exposureresponse can also result from 

misclassification of exposure estimates 

for the more highly-exposed cohort 

members (Staynor et al., 2003). OSHA’s 

evaluation of individual cohort studies 

discussed below indicates that, with the 

exception of the Vermont granite cohort, 

attenuation of exposure-related lung 

cancer response has not been directly 

observed. 

In addition to the pooled cohort 

study, OSHA’s Preliminary Quantitative 

Risk Assessment presents risk estimates 

derived from four individual studies 

where investigators presented either 

lung cancer risk estimates or exposureresponse coefficients. Two of these 

studies, one on diatomaceous earth 

workers (Rice et al., 2001) and one on 

Vermont granite workers (Attfield and 

Costello, 2004), were included in the 10- 

cohort pooled study (Steenland et al., 

2001a; Toxichemica, 2004). The other 

two were of British coal miners (Miller 

et al., 2007; Miller and MacCalman, 

2010) and North American industrial 

sand workers (Hughes et al., 2001). 

Rice et al. (2001) presents an 

exposure-response analysis of the 

diatomaceous worker cohort studied by 

Checkoway et al. (1993, 1996, 1997), 

who found a significant relationship 

between exposure to respirable 

cristobalite and increased lung cancer 

mortality. The cohort consisted of 2,342 

white males employed for at least one 

year between 1942 and 1987 in a 

California diatomaceous earth mining 

and processing plant. The cohort was 

followed until 1994, and included 77 

lung cancer deaths. The risk analysis 

relied on an extensive job-specific 

exposure assessment developed by 

Sexias et al. (1997), which included use 

of over 6,000 samples taken during the 

period 1948 through 1988. The mean 

cumulative exposure for the cohort was 

2.16 mg/m3-years for respirable 

crystalline silica dust. Rice et al. (2001) 

evaluated several model forms for the 

exposure-response analysis and found 

exposure to respirable cristobalite to be 

a significant predictor of lung cancer 

mortality with the best-fitting model 

being a linear relative risk model (with 

a 15-year exposure lag). From this 

model, the estimates of the excess risk 

of lung cancer mortality are 34, 17, and 

9 deaths per 1,000 workers for 45-years 

of exposure to 0.1, 0.05, and 0.025 mg/ 

m3, respectively. For exposures in the 

range of the current construction and 

shipyard PELs over 45 years, estimated 

risks lie in a range between 81 and 152 

deaths per 1,000 workers. 

Somewhat higher risk estimates are 

derived from the analysis presented by 

Attfield and Costello (2004) of Vermont 

granite workers. This study involved a 

cohort of 5,414 male granite workers 

who were employed in the Vermont 

granite industry between 1950 and 1982 

and who were followed through 1994. 

Workers’ cumulative exposures were 

estimated by Davis et al. (1983) based on 

historical exposure data collected in six 

environmental surveys conducted 

between 1924 and 1977. A categorical 

analysis showed an increasing trend of 

lung cancer risk ratios with increasing 

exposure, and Poisson regression was 

used to evaluate several exposureresponse models with varying exposure 

lags and use of either untransformed or 

log-transformed exposure metrics. The 

best-fitting model was based on use of 

a 15-year lag, use of untransformed 

cumulative exposure, and omission of 

the highest exposure group. The 

investigators believed that the omission 

of the highest exposure group was 

appropriate since: (1) The underlying 

exposure data for the high-exposure 

group was weaker than for the others; 

(2) there was a greater likelihood that 

competing causes of death and 

misdiagnoses of causes of death 

attenuated the lung cancer death rate in 

the highest exposure group; (3) all of the 

remaining groups comprised 85 percent 

of the deaths in the cohort and showed 

a strong linear increase in lung cancer 

mortality with increasing exposure; and 

(4) the exposure-response relationship 

seen in the lower exposure groups was 

more relevant given that the exposures 

of these groups were within the range of 

current occupational standards. OSHA’s 

use of the exposure coefficient from this 

analysis in a log-linear relative risk 

model yielded a risk estimate of 60 

deaths per 1,000 workers for 45 years of 

exposure to the current general industry 

PEL of 0.1 mg/m3, 25 deaths per 1,000 

for 45 years of exposure to the proposed 

PEL of 0.05 mg/m3, and 11 deaths per 

1,000 for 45 years of exposure at the 

proposed action level of 0.025 mg/m3. 

Estimated risks associated with 45 years 

of exposure at the current construction 

PEL range from 250 to 653 deaths per 

1,000. 

Hughes et al. (2001) conducted a 

nested case-control study of 95 lung 

cancer deaths from a cohort of 2,670 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56331 

industrial sand workers in the U.S. and 

Canada studied by McDonald et al. 

(2001). (This cohort overlaps with the 

cohort studied by Steenland and 

Sanderson (2001), which was included 

in the 10-cohort pooled study by 

Steenland et al., 2001a). Both categorical 

analyses and conditional logistic 

regression were used to examine 

relationships with cumulative exposure, 

log of cumulative exposure, and average 

exposure. Exposure levels over time 

were estimated via a job-exposure 

matrix developed for this study (Rando 

et al., 2001). The 50th percentile 

(median) exposure level of cases and 

controls for lung cancer were 0.149 and 

0.110 mg/m3 respirable crystalline 

silica, respectively, slightly above the 

current OSHA general industry 

standard. There did not appear to be 

substantial misclassification of 

exposures, as evidenced by silicosis 

mortality showing a positive exposureresponse trend with cumulative 

exposure and average exposure 

concentration. Statistically significant 

positive exposure-response trends for 

lung cancer were found for both 

cumulative exposure (lagged 15 years) 

and average exposure concentration, but 

not for duration of employment, after 

controlling for smoking. There was no 

indication of an interaction effect of 

smoking and cumulative silica 

exposure. Hughes et al. (2001) reported 

the exposure coefficients for both lagged 

and unlagged cumulative exposure; 

there was no significant difference 

between the two (0.13 per mg/m3-year 

for lagged vs. 0.14 per mg/m3-year for 

unlagged). Use of the coefficient from 

Hughes et al. (2001) that incorporated a 

15-year lag generates estimated cancer 

risks of 34, 15, and 7 deaths per 1,000 

for 45 years exposure to the current 

general industry PEL of 0.1, the 

proposed PEL of 0.05 mg/m3, and the 

proposed action level of 0.025 mg/m3

respirable silica, respectively. For 45 

years of exposure to the construction 

PEL, estimated risks range from 120 to 

387 deaths per 1,000 workers. 

Miller and MacCalman (2010, also 

reported in Miller et al., 2007) extended 

the follow-up of a previously published 

cohort mortality study (Miller and 

Buchanan, 1997). The follow-up study 

included 17,800 miners from 10 coal 

mines in the U.K. who were followed 

through the end of 2005; observation in 

the original study began in 1970. By 

2005, there were 516,431 person years 

of observation, an average of 29 years 

per miner, with 10,698 deaths from all 

causes. Exposure estimates of cohort 

members were not updated from the 

earlier study since the mines closed in 

the 1980s; however, some of these men 

might have had additional exposure at 

other mines or facilities. An analysis of 

cause-specific mortality was performed 

using external controls; it demonstrated 

that lung cancer mortality was 

statistically significantly elevated for 

coal miners exposed to silica. An 

analysis using internal controls was 

performed via Cox proportional hazards 

regression methods, which allowed for 

each individual miner’s measurements 

of age and smoking status, as well as the 

individual’s detailed dust and quartz 

time-dependent exposure 

measurements. From the Cox regression, 

Miller and MacCalman (2009) estimated 

that cumulative exposure of 5 g-h/m3

respirable quartz (incorporating a 15- 

year lag) was associated with a relative 

risk of 1.14 for lung cancer. This 

cumulative exposure is about equivalent 

to 45 years of exposure to 0.055 mg/m3

respirable quartz, or a cumulative 

exposure of 2.25 mg/m3-yr, assuming 

2,000 hours of exposure per year. OSHA 

applied this slope factor in a log-relative 

risk model and estimated the lifetime 

lung cancer mortality risk to be 13 per 

1,000 for 45 years of exposure to 0.1 mg/ 

m3 respirable crystalline silica. For the 

proposed PEL of 0.05 mg/m3 and 

proposed action level of 0.025 mg/m3, 

the lifetime risks are estimated to be 6 

and 3 deaths per 1,000, respectively. 

The range of risks estimated to result 

from 45 years of exposure to the current 

construction and shipyard PELs is from 

37 to 95 deaths per 1,000 workers. 

The analysis from the Miller and 

MacCalman (2009) study yields risk 

estimates that are lower than those 

obtained from the other cohort studies 

described above. Possible explanations 

for this include: (1) Unlike the studies 

on diatomaceous earth workers and 

granite workers, the mortality analysis 

of the coal miners was adjusted for 

smoking; (2) lung cancer risks might 

have been lower among the coal miners 

due to high competing mortality risks 

observed in the cohort (mortality was 

significantly increased for several 

diseases, including tuberculosis, 

chronic bronchitis, and non-malignant 

respiratory disease); and (3) the lower 

risk estimates derived from the coal 

miner study could reflect an actual 

difference in the cancer potency of the 

quartz dust in the coal mines compared 

to that present in the work 

environments studied elsewhere. OSHA 

believes that the risk estimates derived 

from this study are credible. In terms of 

design, the cohort was based on union 

rolls with very good participation rates 

and good reporting. The study group 

was the largest of any of the individual 

cohort studies reviewed here (over 

17,000 workers) and there was an 

average of nearly 30 years of follow-up, 

with about 60 percent of the cohort 

having died by the end of follow-up. 

Just as important were the high quality 

and detail of the exposure 

measurements, both of total dust and 

quartz. 

b. Summary of Risk Estimates for 

Silicosis and Other Chronic Lung 

Disease Mortality 

OSHA based its quantitative 

assessment of silicosis mortality risks on 

a pooled analysis conducted by 

Mannetje et al. (2002b) of data from six 

of the ten epidemiological studies in the 

Steenland et al. (2001a) pooled analysis 

of lung cancer mortality. Cohorts 

included in the silicosis study were U.S. 

diatomaceous earth workers 

(Checkoway et al., 1997); Finnish 

granite workers (Koskela et al., 1994); 

U.S. granite workers (Costello and 

Graham, 1988); U.S. industrial sand 

workers (Steenland and Sanderson, 

2001); U.S. gold miners (Steenland and 

Brown, 1995b); and Australian gold 

miners (deKlerk and Musk, 1998). These 

six cohorts contained 18,634 subjects 

and 170 silicosis deaths, where silicosis 

mortality was defined as death from 

silicosis (ICD–9 502, n=150) or from 

unspecified pneumoconiosis (ICD–9 

505, n = 20). Analysis of exposureresponse was performed in a categorical 

analysis where the cohort was divided 

into cumulative exposure deciles and 

Poisson regression was used to estimate 

silicosis rate ratios for each category, 

adjusted for age, calendar period, and 

study. Exposure-response was examined 

in more detail using a nested casecontrol design and logistic regression. 

Although Mannetje et al. (2002b) 

estimated silicosis risks at the current 

OSHA PEL from the Poisson regression, 

a subsequent analysis based on the casecontrol design was conducted by 

Steenland and Bartow (Toxichemica, 

2004), which resulted in slightly lower 

estimates of risk. Based on the 

Toxichemica analysis, OSHA estimates 

that the lifetime risk (over 85 years) of 

silicosis mortality associated with 45 

years of exposure to the current general 

industry PEL of 0.1 mg/m3 is 11 deaths 

per 1,000 workers. Exposure for 45 years 

to the proposed PEL of 0.05 mg/m3 and 

action level of 0.025 mg/m3 results in an 

estimated 7 and 4 silicosis deaths per 

1,000, respectively. Lifetime risks 

associated with exposure at the current 

construction and shipyard PELs range 

from 17 to 22 deaths per 1,000 workers. 

To study non-malignant respiratory 

diseases, of which silicosis is one, Park 

et al. (2002) analyzed the California 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56332 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

diatomaceous earth cohort data 

originally studied by Checkoway et al. 

(1997), consisting of 2,570 diatomaceous 

earth workers employed for 12 months 

or more from 1942 to 1994. The authors 

quantified the relationship between 

exposure to cristobalite and mortality 

from chronic lung disease other than 

cancer (LDOC). Diseases in this category 

included pneumoconiosis (which 

included silicosis), chronic bronchitis, 

and emphysema, but excluded 

pneumonia and other infectious 

diseases. Less than 25 percent of the 

LDOC deaths in the analysis were coded 

as silicosis or other pneumoconiosis (15 

of 67). As noted by Park et al. (2002), it 

is likely that silicosis as a cause of death 

is often misclassified as emphysema or 

chronic bronchitis. Exposure-response 

relationships were explored using both 

Poisson regression models and Cox’s 

proportional hazards models fit to the 

same series of relative rate exposureresponse models that were evaluated by 

Rice et al. (2001) for lung cancer (i.e., 

log-linear, log-square root, log-quadratic, 

linear relative rate, a power function, 

and a shape function). Relative or excess 

rates were modeled using internal 

controls and adjusting for age, calendar 

time, ethnicity (Hispanic versus white), 

and time since first entry into the 

cohort, or using age- and calendar timeadjusted external standardization to 

U.S. population mortality rates. There 

were no LDOC deaths recorded among 

workers having cumulative exposures 

above 32 mg/m3-years, causing the 

response to level off or decline in the 

highest exposure range; possible 

explanations considered included 

survivor selection, depletion of 

susceptible populations in high dust 

areas, and/or a higher degree of 

misclassification of exposures in the 

earlier years where exposure data were 

lacking and when exposures were 

presumably the highest. Therefore, Park 

et al. (2002) performed exposureresponse analyses that restricted the 

dataset to observations where 

cumulative exposures were below 10 

mg/m3-years, a level more than four 

times higher than that resulting from 45 

years of exposure to the current general 

industry PEL for cristobalite (which is 

about 0.05 mg/m3), as well as analyses 

using the full dataset. Among the 

models based on the restricted dataset, 

the best-fitting model with a single 

exposure term was the linear relative 

rate model using external adjustment. 

OSHA’s estimates of the lifetime 

chronic lung disease mortality risk 

based on this model are substantially 

higher than those that OSHA derived 

from the Mannetje et al. (2002b) silicosis 

analysis. For the current general 

industry PEL of 0.1 mg/m3, exposure for 

45 years is estimated to result in 83 

deaths per 1,000 workers. At the 

proposed PEL of 0.05 mg/m3 and action 

level of 0.025 mg/m3, OSHA estimates 

the lifetime risk from 45 years of 

exposure to be 43 and 22 deaths per 

1,000, respectively. The range of risks 

associated with exposure at the 

construction and shipyard PELs over a 

working lifetime is from 188 to 321 

deaths per 1,000 workers. It should be 

noted that the Mannetje study (2002b) 

was not adjusted for smoking while the 

Park study (2002) had data on smoking 

habits for about one-third of the workers 

who died from LDOC and about half of 

the entire cohort. The Poisson 

regression on which the risk model is 

based was partially stratified on 

smoking. Furthermore, analyses without 

adjustment for smoking suggested to the 

authors that smoking was acting as a 

negative confounder. 

c. Summary of Risk Estimates for Renal 

Disease Mortality 

OSHA’s analysis of the health effects 

literature included several studies that 

have demonstrated that exposure to 

crystalline silica increases the risk of 

renal and autoimmune disease (see 

Section V, Health Effects Summary). 

Studies have found statistically 

significant associations between 

occupational exposure to silica dust and 

chronic renal disease, sub-clinical renal 

changes, end-stage renal disease 

morbidity, chronic renal disease 

mortality, and Wegener’s 

granulomatosis. A strong exposureresponse association for renal disease 

mortality and silica exposure has also 

been demonstrated. 

OSHA’s assessment of the renal 

disease risks that result from exposure 

to respirable crystalline silica are based 

on an analysis of pooled data from three 

cohort studies (Steenland et al., 2002a). 

The combined cohort for the pooled 

analysis (Steenland et al., 2002a) 

consisted of 13,382 workers and 

included industrial sand workers 

(Steenland et al., 2001b), U.S. gold 

miners (Steenland and Brown, 1995a), 

and Vermont granite workers (Costello 

and Graham, 1998). Exposure data were 

available for 12,783 workers and 

analyses conducted by the original 

investigators demonstrated 

monotonically increasing exposureresponse trends for silicosis, indicating 

that exposure estimates were not likely 

subject to significant random 

misclassification. The mean duration of 

exposure, cumulative exposure, and 

concentration of respirable silica for the 

combined cohort were 13.6 years, 1.2 

mg/m3-years, and 0.07 mg/m3, 

respectively. There were highly 

statistically significant trends for 

increasing renal disease mortality with 

increasing cumulative exposure for both 

multiple cause analysis of mortality 

(p<0.000001) and underlying cause 

analysis (p = 0.0007). Exposureresponse analysis was also conducted as 

part of a nested case-control study, 

which showed statistically significant 

monotonic trends of increasing risk with 

increasing exposure again for both 

multiple cause (p = 0.004 linear trend, 

0.0002 log trend) and underlying cause 

(p = 0.21 linear trend, 0.03 log trend) 

analysis. The authors found that use of 

log-cumulative dose in a log relative risk 

model fit the pooled data better than 

cumulative exposure, average exposure, 

or lagged exposure. OSHA’s estimates of 

renal disease mortality risk, which are 

based on the log relative risk model 

with log cumulative exposure, are 39 

deaths per 1,000 for 45 years of 

exposure at the current general industry 

PEL of 0.1 mg/m3, 32 deaths per 1,000 

for exposure at the proposed PEL of 0.05 

mg/m3, and 25 deaths per 1,000 at the 

proposed action level of 0.025 mg/m3. 

OSHA also estimates that 45 years of 

exposure at the current construction and 

shipyard PELs would result in a renal 

disease mortality risk ranging from 52 to 

63 deaths per 1,000 workers. 

d. Summary of Risk Estimates for 

Silicosis Morbidity 

OSHA’s Preliminary Quantitative Risk 

Assessment reviewed several crosssectional studies designed to 

characterize relationships between 

exposure to respirable crystalline silica 

and development of silicosis as 

determined by chest radiography. 

Several of these studies could not 

provide information on exposure or 

length of employment prior to disease 

onset. Others did have access to 

sufficient historical medical data to 

retrospectively determine time of 

disease onset but included medical 

examination at follow up of primarily 

active workers with little or no postemployment follow-up. Although OSHA 

presents silicosis risk estimates that 

were reported by the investigators of 

these studies, OSHA believes that such 

estimates are likely to understate 

lifetime risk of developing radiological 

silicosis; in fact, the risk estimates 

reported in these studies are generally 

lower than those derived from studies 

that included retired workers in follow 

up medical examinations. 

Therefore, OSHA believes that the 

most useful studies for characterizing 

lifetime risk of silicosis morbidity are 

retrospective cohort studies that 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56333 

included a large proportion of retired 

workers in the cohort and that were able 

to evaluate disease status over time, 

including post-retirement. OSHA 

identified studies of six cohorts for 

which the inclusion of retirees was 

deemed sufficient to adequately 

characterize silicosis morbidity risks 

well past employment (Hnizdo and 

Sluis-Cremer, 1993; Steenland and 

Brown, 1995b; Miller et al., 1998; 

Buchanan et al., 2003; Chen et al., 2001; 

Chen et al., 2005). Study populations 

included five mining cohorts and a 

Chinese pottery worker cohort. Except 

for the Chinese studies (Chen et al., 

2001; Chen et al., 2005), chest 

radiographs were interpreted in 

accordance with the ILO system 

described earlier in this section, and xray films were read by panels of Breaders. In the Chinese studies, films 

were evaluated using a Chinese system 

of classification that is analogous to the 

ILO system. In addition, the Steenland 

and Brown (1995b) study of U.S. gold 

miners included silicosis mortality as 

well as morbidity in its analysis. 

OSHA’s estimates of silicosis morbidity 

risks are based on implementing the 

various exposure-response models 

reported by the investigators; these are 

considered to be cumulative risk models 

in the sense that they represent the risk 

observed in the cohort at the time of the 

last medical evaluation and do not 

reflect all of the risk that may become 

manifest over a lifetime. With the 

exception of a coal miner study 

(Buchanan et al., 2003), risk estimates 

reflect the risk that a worker will 

acquire an abnormal chest x-ray 

classified as ILO major category 1 or 

greater; the coal miner study evaluated 

the risk of acquiring an abnormal chest 

x-ray classified as major category 2 or 

higher. 

For miners exposed to freshly cut 

crystalline silica, the estimated risk of 

developing lesions consistent with an 

ILO classification of category 1 or 

greater is estimated to range from 120 to 

773 cases per 1,000 workers exposed at 

the current general industry PEL of 0.1 

mg/m3 for 45 years. For 45 years of 

exposure to the proposed PEL of 0.05 

mg/m3, the range in estimated risk is 

from 20 to 170 cases per 1,000 workers. 

The risk predicted from exposure to the 

proposed action level of 0.025 mg/m3

ranges from 5 to 40 cases per 1,000. 

From the coal miner study of Buchanan 

et al. (2003), the estimated risks of 

acquiring an abnormal chest x-ray 

classified as ILO category 2 or higher are 

301, 55, and 21 cases per 1,000 workers 

exposed for 45 years to 0.1, 0.05, and 

0.025 mg/m3, respectively. These 

estimates are within the range of risks 

obtained from the other mining studies. 

At exposures at or above 0.25 mg/m3 for 

45 years (equivalent to the current 

construction and shipyard PELs), the 

risk of acquiring an abnormal chest xray approaches unity. Risk estimates 

based on the pottery cohort are 60, 20, 

and 5 cases per 1,000 workers exposed 

for 45 years to 0.1, 0.05, and 0.025 mg/ 

m3, respectively, which is generally 

below the range of risks estimated from 

the other studies and may reflect a 

lower toxicity of quartz particles in that 

work environment due to the presence 

of alumino-silicates on the particle 

surfaces. According to Chen et al. 

(2005), adjustment of the exposure 

metric to reflect the unoccluded surface 

area of silica particles resulted in an 

exposure-response of pottery workers 

that was similar to the mining cohorts. 

The finding of a reduced silicosis risk 

among pottery workers is consistent 

with other studies of clay and brick 

industries that have reported finding a 

lower prevalence of silicosis compared 

to that experienced in other industry 

sectors (Love et al., 1999; Hessel, 2006; 

Miller and Soutar, 2007) as well as a 

lower silicosis risk per unit of 

cumulative exposure (Love et al., 1999; 

Miller and Soutar, 2007). 

3. Significance of Risk and Risk 

Reduction 

The Supreme Court’s benzene 

decision of 1980, discussed above in 

this section, states that ‘‘before he can 

promulgate any permanent health or 

safety standard, the Secretary [of Labor] 

is required to make a threshold finding 

that a place of employment is unsafe— 

in the sense that significant risks are 

present and can be eliminated or 

lessened by a change in practices.’’ 

Benzene, 448 U.S. at 642. While making 

it clear that it is up to the Agency to 

determine what constitutes a significant 

risk, the Court offered general guidance 

on the level of risk OSHA might 

determine to be significant. 

It is the Agency’s responsibility to 

determine in the first instance what it 

considers to be a ‘‘significant’’ risk. Some 

risks are plainly acceptable and others are 

plainly unacceptable. If, for example, the 

odds are one in a billion that a person will 

die from cancer by taking a drink of 

chlorinated water, the risk clearly could not 

be considered significant. On the other hand, 

if the odds are one in a thousand that regular 

inhalation of gasoline vapors that are 2% 

benzene will be fatal, a reasonable person 

might well consider the risk significant and 

take appropriate steps to decrease or 

eliminate it. 

Benzene, 448 U.S. at 655. The Court 

further stated that the determination of 

significant risk is not a mathematical 

straitjacket and that ‘‘the Agency has no 

duty to calculate the exact probability of 

harm.’’ Id. 

In this section, OSHA presents its 

preliminary findings with respect to the 

significance of the risks summarized 

above, and the potential of the proposed 

standard to reduce those risks. Findings 

related to mortality risk will be 

presented first, followed by silicosis 

morbidity risks. 

a. Mortality Risks 

OSHA’s Preliminary Quantitative Risk 

Assessment (and the Summary of the 

Preliminary Quantitative Risk 

Assessment in section VI) presents risk 

estimates for four causes of excess 

mortality: Lung cancer, silicosis, nonmalignant respiratory disease (including 

silicosis and COPD), and renal disease. 

Table VII–2 presents the estimated 

excess lifetime risks (i.e., to age 85) of 

these fatal diseases associated with 

various levels of crystalline silica 

exposure allowed under the current 

rule, based on OSHA’s risk assessment 

and assuming 45 years of occupational 

exposure to crystalline silica. 

TABLE VII–2—EXPECTED EXCESS DEATHS PER 1,000 WORKERS

Fatal health outcome 

Current general 

industry PEL 

(0.1 mg/m3) 

Current 

construction/ 

shipyard PEL 

(0.25–0.5 mg/m3) 

Proposed PEL 

(0.05 mg/m3) 

Lung Cancer: 

10-cohort pooled analysis ........................................................................................ 22–29 27–38 18–26 

Single cohort study-lowest estimate ......................................................................... 13 37–95 6 

Single cohort study-highest estimate ....................................................................... 60 250–653 25 

Silicosis ............................................................................................................................ 11 17–22 7 

Non-Malignant Respiratory Disease (including silicosis) ................................................ 83 188–321 43 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56334 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VII–2—EXPECTED EXCESS DEATHS PER 1,000 WORKERS—Continued 

Fatal health outcome 

Current general 

industry PEL 

(0.1 mg/m3) 

Current 

construction/ 

shipyard PEL 

(0.25–0.5 mg/m3) 

Proposed PEL 

(0.05 mg/m3) 

Renal Disease ................................................................................................................. 39 52–63 32 

The purpose of the OSH Act, as stated 

in Section 6(b), is to ensure ‘‘that no 

employee will suffer material 

impairment of health or functional 

capacity even if such employee has 

regular exposure to the hazard . . . for 

the period of his working life.’’ 29 

U.S.C. 655(b)(5). Assuming a 45-year 

working life, as OSHA has done in 

significant risk determinations for 

previous standards, the Agency 

preliminarily finds that the excess risk 

of disease mortality related to exposure 

to respirable crystalline silica at levels 

permitted by current OSHA standards is 

clearly significant. The Agency’s 

estimate of such risk falls well above the 

level of risk the Supreme Court 

indicated a reasonable person might 

consider unacceptable. Benzene, 448 

U.S. at 655. For lung cancer, OSHA 

estimates the range of risk at the current 

general industry PEL to be between 13 

and 60 deaths per 1,000 workers. The 

estimated risk for silicosis mortality is 

lower, at 11 deaths per 1,000 workers; 

however, the estimated lifetime risk for 

non-malignant respiratory disease 

mortality, including silicosis, is about 8- 

fold higher than that for silicosis alone, 

at 83 deaths per 1,000. OSHA believes 

that the estimate for non-malignant 

respiratory disease mortality is better 

than the estimate for silicosis mortality 

at capturing the total respiratory disease 

burden associated with exposure to 

crystalline silica dust. The former 

captures deaths related to COPD, for 

which there is strong evidence of a 

causal relationship with exposure to 

silica, and is also more likely to capture 

those deaths where silicosis was a 

contributing factor but where the cause 

of death was misclassified. Finally, 

there is an estimated lifetime risk of 

renal disease mortality of 39 deaths per 

1,000. Exposure for 45 years at levels of 

respirable crystalline silica in the range 

of the current limits for construction 

and shipyards result in even higher risk 

estimates, as presented in Table VII–2. 

To further demonstrate significant 

risk, OSHA compares the risk from 

currently permissible crystalline silica 

exposures to risks found across a broad 

variety of occupations. The Agency has 

used similar occupational risk 

comparisons in the significant risk 

determination for substance-specific 

standards promulgated since the 

benzene decision. This approach is 

supported by evidence in the legislative 

record, with regard to Section 6(b)(5) of 

the Act (29 U.S.C. 655(b)(5)), that 

Congress intended the Agency to 

regulate unacceptably severe 

occupational hazards, and not ‘‘to 

establish a utopia free from any 

hazards’’ or to address risks comparable 

to those that exist in virtually any 

occupation or workplace. 116 Cong. 

Rec. 37614 (1970), Leg. Hist. 480–82. It 

is also consistent with Section 6(g) of 

the OSH Act, which states: ‘‘In 

determining the priority for establishing 

standards under this section, the 

Secretary shall give due regard to the 

urgency of the need for mandatory 

safety and health standards for 

particular industries, trades, crafts, 

occupations, businesses, workplaces or 

work environments.’’ 29 U.S.C. 655(g). 

Fatal injury rates for most U.S. 

industries and occupations may be 

obtained from data collected by the 

Bureau of Labor Statistics. Table VII–3 

shows annual fatality rates per 1,000 

employees for several industries for 

2007, as well as projected fatalities per 

1,000 employees assuming exposure to 

workplace hazards for 45 years based on 

these annual rates (BLS, 2010). While it 

is difficult to meaningfully compare 

aggregate industry fatality rates to the 

risks estimated in the quantitative risk 

assessment for crystalline silica, which 

address one specific hazard (inhalation 

exposure to respirable crystalline silica) 

and several health outcomes (lung 

cancer, silicosis, NMRD, renal disease 

mortality), these rates provide a useful 

frame of reference for considering risk 

from inhalation exposure to crystalline 

silica. For example, OSHA’s estimated 

range of 6–60 excess lung cancer deaths 

per 1,000 workers from regular 

occupational exposure to respirable 

crystalline silica in the range of 0.05— 

0.1 mg/m3 is roughly comparable to, or 

higher than, the expected risk of fatal 

injuries over a working life in high-risk 

occupations such as mining and 

construction (see Table VII–3). Regular 

exposures at higher levels, including the 

current construction and shipyard PELs 

for respirable crystalline silica, are 

expected to cause substantially more 

deaths per 1,000 workers from lung 

cancer (ranging from 37 to 653 per 

1,000) than result from occupational 

injuries in most private industry. At the 

proposed PEL of 0.05 mg/m3 respirable 

crystalline silica, the Agency’s estimate 

of excess lung cancer mortality, from 6 

to 26 deaths per 1,000 workers, is still 

3- to10-fold or more higher than private 

industry’s average fatal injury rate, 

given the same employment time, and 

substantially exceeds those rates found 

in lower-risk industries such as finance 

and educational and health services. 

TABLE VII–3—FATAL INJURIES PER 1000 EMPLOYEES, BY INDUSTRY OR SECTOR

Over 1 year Over 45 years 

All Private Industry ................................................................................................................................................... 0.043 1.9 

Mining (General) ...................................................................................................................................................... 0.214 9.6 

Construction ............................................................................................................................................................. 0.108 4.8 

Manufacturing .......................................................................................................................................................... 0.024 1.1 

Wholesale Trade ...................................................................................................................................................... 0.045 2.0 

Transportation and Warehousing ............................................................................................................................ 0.165 7.4 

Financial Activities ................................................................................................................................................... 0.012 0.5 

Educational and Health Services ............................................................................................................................ 0.008 0.4 

Source: BLS (2010). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56335 

Because there is little available 

information on the incidence of 

occupational cancer across all 

industries, risk from crystalline silica 

exposure cannot be compared with 

overall risk from other workplace 

carcinogens. However, OSHA’s previous 

risk assessments provide estimates of 

risk from exposure to certain 

carcinogens. These risk assessments, as 

with the current assessment for 

crystalline silica, were based on animal 

or human data of reasonable or high 

quality and used the best information 

then available. Table VII–4 shows the 

Agency’s best estimates of cancer risk 

from 45 years of occupational exposure 

to several carcinogens, as published in 

the preambles to final rules promulgated 

since the benzene decision in 1980. 

These risks were judged by the Agency 

to be significant. 

TABLE VII–4—SELECTED OSHA RISK ESTIMATES FOR PRIOR AND CURRENT PELS

[Excess Cancers per 1000 workers] 

Standard Risk at prior PEL Risk at current PEL Federal Register date 

Ethylene Oxide .................................................................. 63–109 per 1000 ................. 1.2–2.3 per 1000 ................. June 22, 1984. 

Asbestos ............................................................................ 64 per 1000 ......................... 6.7 per 1000 ........................ June 20, 1986. 

Benzene ............................................................................. 95 per 1000 ......................... 10 per 1000 ......................... September 11, 1987. 

Formaldehyde .................................................................... 0.4–6.2 per 1000 ................. 0.0056 per 1000 .................. December 4, 1987. 

Methylenedianiline ............................................................. *6–30 per 1000 ................... 0.8 per 1000 ........................ August 10, 1992. 

Cadmium ............................................................................ 58–157 per 1000 ................. 3–15 per 1000 ..................... September 14, 1992. 

1,3-Butadiene ..................................................................... 11.2–59.4 per 1000 ............. 1.3–8.1 per 1000 ................. November 4, 1996. 

Methylene Chloride ............................................................ 126 per 1000 ....................... 3.6 per 1000 ........................ January 10, 1997. 

Chromium VI ...................................................................... 101–351 per 1000 ............... 10–45 per 1000 ................... February 28, 2006 

Crystalline Silica: 

General Industry PEL ................................................. **13–60 per 1000 ................ ***6–26 per 1000 ................. N/A 

Construction/Shipyard PEL ........................................ **27–653 per 1000 .............. ***6–26 per 1000 .................

* no prior standard; reported risk is based on estimated exposures at the time of the rulemaking 

** estimated excess lung cancer risks at the current PEL 

*** estimated excess lung cancer risks at the proposed new PEL 

The estimated excess lung cancer 

risks associated with respirable 

crystalline silica at the current general 

industry PEL, 13–60 deaths per 1,000 

workers, are comparable to, and in some 

cases higher than, the estimated excess 

cancer risks for many other workplace 

carcinogens for which OSHA made a 

determination of significant risk (see 

Table VII–4, ‘‘Selected OSHA Risk 

Estimates for Prior and Current PELs’’). 

The estimated excess lung cancer risks 

associated with exposure to the current 

construction and shipyard PELs are 

even higher. The estimated risk from 

lifetime occupational exposure to 

respirable crystalline silica at the 

proposed PEL is 6–26 excess lung 

cancer deaths per 1,000 workers, a range 

still higher than the risks from exposure 

to many other carcinogens regulated by 

OSHA (see Table VII–4, ‘‘Selected 

OSHA Risk Estimates for Prior and 

Current PELs’’). 

OSHA’s preliminary risk assessment 

also shows that reduction of the current 

PELs to the proposed level of 0.05 mg/ 

m3 will result in substantial reduction 

in risk, although quantification of that 

reduction is subject to model 

uncertainty. Risk models that reflect 

attenuation of the risk with increasing 

exposure, such as those relating risk to 

a log transformation of cumulative 

exposure, will result in lower estimates 

of risk reduction compared to linear risk 

models. Thus, for lung cancer risks, the 

assessment based on the 10-cohort 

pooled analysis by Steenland et al. 

(2001; also Toxichemica, 2004; 

Steenland 2010) suggests risk will be 

reduced by about 14 percent from the 

current general industry PEL and by 28– 

41 percent from the current 

construction/shipyard PEL (based on 

the midpoint of the ranges of estimated 

risk derived from the three models used 

for the pooled cohort data). These risk 

reduction estimates, however, are much 

lower than those derived from the single 

cohort studies (Rice et al., 2001; Attfield 

and Costello, 2004; Hughes et al., 2001; 

Miller and MacCalman, 2009), which 

used linear or log-linear relative risk 

models with untransformed cumulative 

exposure as the dose metric. These 

single cohort studies suggest that 

reducing the current PELs to the 

proposed PEL will reduce lung cancer 

risk by more than 50 percent in general 

industry and by more than 80 percent in 

construction and shipyards. 

For silicosis mortality, OSHA’s 

assessment indicates that risk will be 

reduced by 36 percent and by 58–68 

percent as a result of reducing the 

current general industry and 

construction/shipyard PELs, 

respectively. Non-malignant respiratory 

disease mortality risks will be reduced 

by 48 percent and by 77–87 percent 

from reducing the general industry and 

construction/shipyard PELs, 

respectively, to the proposed PEL. There 

is also a substantial reduction in renal 

disease mortality risks; an 18-percent 

reduction associated with reducing the 

general industry PEL and a 38- to 49- 

percent reduction associated with 

reducing the construction/shipyard PEL. 

Thus, OSHA believes that the 

proposed PEL of 0.05 mg/m3 respirable 

crystalline silica will substantially 

reduce the risk of material health 

impairments associated with exposure 

to silica. However, even at the proposed 

PEL, as well as the action level of 0.025 

mg/m3, the risk posed to workers with 

45 years of regular exposure to 

respirable crystalline silica is greater 

than 1 per 1,000 workers and is still 

clearly significant. 

b. Silicosis Morbidity Risks 

OSHA’s Preliminary Risk Assessment 

characterizes the risk of developing lung 

fibrosis as detected by chest x-ray. For 

45 years of exposure at the current 

general industry PEL, OSHA estimates 

that the risk of developing lung fibrosis 

consistent with an ILO category 1+ 

degree of small opacity profusion ranges 

from 60 to 773 cases per 1,000. For 

exposure at the construction and 

shipyard PELs, the risk approaches 

unity. The wide range of risk estimates 

derived from the underlying studies 

relied on for the risk assessment may 

reflect differences in the relative toxicity 

of quartz particles in different 

workplaces; nevertheless, OSHA 

believes that each of these risk estimates 

clearly represent a significant risk of 

developing fibrotic lesions in the lung. 

Exposure to the proposed PEL of 0.05 

mg/m3 respirable crystalline silica for 

45 years yields an estimated risk of 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56336 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

between 20 and 170 cases per 1,000 for 

developing fibrotic lesions consistent 

with an ILO category of 1+. These risk 

estimates indicate that promulgation of 

the proposed PEL would result in a 

reduction in risk by about two-thirds or 

more, which the Agency believes is a 

substantial reduction of the risk of 

developing abnormal chest x-ray 

findings consistent with silicosis. 

One study of coal miners also 

permitted the agency to evaluate the risk 

of developing lung fibrosis consistent 

with an ILO category 2+ degree of 

profusion of small opacities (Buchanan 

et al., 2003). This level of profusion has 

been shown to be associated with a 

higher prevalence of lung function 

decrement and an increased rate of early 

mortality (Ng et al., 1987a; Begin et al., 

1998; Moore et al., 1988; Ng et al., 

1992a; Infante-Rivard et al., 1991). From 

this study, OSHA estimates that the risk 

associated with 45 years of exposure to 

the current general industry PEL is 301 

cases per 1,000 workers, again a clearly 

significant risk. Exposure to the 

proposed PEL of 0.05 mg/m3 respirable 

crystalline silica for 45 years yields an 

estimated risk of 55 cases per 1,000 for 

developing lesions consistent with an 

ILO category 2+ degree of small opacity 

profusion. This represents a reduction 

in risk of over 80 percent, again a clearly 

substantial reduction of the risk of 

developing radiologic silicosis 

consistent with ILO category 2+ degree 

of small opacity profusion. 

As is the case for other health effects 

addressed in the preliminary risk 

assessment (i.e., lung cancer, silicosis 

morbidity defined as ILO 1+ level of 

profusion), there is some evidence that 

this risk will vary according to the 

nature of quartz particles present in 

different workplaces. In particular, risk 

may vary depending on whether quartz 

is freshly fractured during work 

operations and the co-existence of other 

minerals and substances that could alter 

the biological activity of quartz. Using 

medical and exposure data taken from a 

cohort of heavy clay workers first 

studied by Love et al. (1999), Miller and 

Soutar (2007) compared the silicosis 

prevalence within the cohort to that 

predicted by the exposure-response 

model derived by Buchanan et al. (2003) 

and used by OSHA to estimate the risk 

of radiologic silicosis with a 

classification of ILO 2+. They found that 

the model predicted about a 4-fold 

higher prevalence of workers having an 

abnormal x-ray than was actually seen 

in the clay cohort (31 cases predicted vs. 

8 observed). Unlike the coal miner 

study, the clay worker cohort included 

only active workers and not retirees 

(Love et al., 1999); however, Miller and 

Soutar believed this could not explain 

the magnitude of the difference between 

the model prediction and observed 

silicosis prevalence in the clay worker 

cohort. OSHA believes that the result 

obtained by Miller and Soutar (2007) 

likely does reflect differences in the 

toxic potency of quartz particles in 

different work settings. Nevertheless, 

even if the risk estimates predicted by 

the model derived from the coal worker 

study were reduced substantially, even 

by more than a factor of 10, the resulting 

risk estimate would still reflect the 

presence of a significant risk. 

The Preliminary Quantitative Risk 

Assessment also discusses the question 

of a threshold exposure level for 

silicosis. There is little quantitative data 

available with which to estimate a 

threshold exposure level for silicosis or 

any of the other silica-related diseases 

addressed in the risk assessment. The 

risk assessment discussed one study 

that perhaps provides the best 

information. This is an analysis by 

Kuempel et al. (2001) who used a ratbased toxicokinetic/toxicodynamic 

model along with a human lung 

deposition/clearance model to estimate 

a minimum lung burden necessary to 

cause the initial inflammatory events 

that can lead to lung fibrosis and an 

indirect genotoxic cause of lung cancer. 

They estimated that the threshold effect 

level of lung burden associated with this 

inflammation (Mcrit) is the equivalent of 

exposure to 0.036 mg/m3 for 45 years; 

thus, exposures below this level would 

presumably not lead to an excess lung 

cancer risk (based on an indirect 

genotoxic mechanism) nor to silicosis, 

at least in the ‘‘average individual.’’ 

This might suggest that exposures to a 

concentration of silica at the proposed 

action level would not be associated 

with a risk of silicosis, and possibly not 

of lung cancer. However, OSHA does 

not believe that the analysis by Kuemple 

et al. is definitive with respect to a 

threshold for silica-related disease. 

First, since the critical quartz burden is 

a mean value derived from the model, 

the authors estimated that a 45-year 

exposure to a concentration as low as 

0.005 mg/m3, or 5 times below the 

proposed action level, would result in a 

lung quartz burden that was equal to the 

95-percent lower confidence limit on 

Mcrit. Due to the statistical uncertainty in 

Kuemple et al.’s estimate of critical lung 

burden, OSHA cannot rule out the 

existence of a threshold lung burden 

that is below that resulting from 

exposure to the proposed action level. 

In addition, with respect to silicarelated lung cancer, if at least some of 

the risk is from a direct genotoxic 

mechanism (see section II.F of the 

Health Effects Literature Review), then 

this threshold value is not relevant to 

the risk of lung cancer. Supporting 

evidence comes from Steenland and 

Deddens (2002), who found that, for the 

10-cohort pooled data set, a risk model 

that incorporated a threshold did fit 

better than a no-threshold model, but 

the estimated threshold was very low, 

0.010 mg/m3 (10 mg/m3). OSHA 

acknowledges that a threshold exposure 

level might lie within the range of the 

proposed action level, as suggested by 

the work of Kuempel et al. (2001) and 

that this possibility adds uncertainty to 

the estimated risks associated with 

exposure to the action level. However, 

OSHA believes that available 

information cannot firmly establish a 

threshold exposure level for silicarelated effects, and there is no empirical 

evidence that a threshold exists at or 

above the proposed PEL of 0.05 mg/m3

for respirable crystalline silica. 

VIII. Summary of the Preliminary 

Economic Analysis and Initial 

Regulatory Flexibility Analysis 

A. Introduction and Summary 

OSHA’s Preliminary Economic 

Analysis and Initial Regulatory 

Flexibility Analysis (PEA) addresses 

issues related to the costs, benefits, 

technological and economic feasibility, 

and the economic impacts (including 

impacts on small entities) of this 

proposed respirable crystalline silica 

rule and evaluates regulatory 

alternatives to the proposed rule. 

Executive Orders 13563 and 12866 

direct agencies to assess all costs and 

benefits of available regulatory 

alternatives and, if regulation is 

necessary, to select regulatory 

approaches that maximize net benefits 

(including potential economic, 

environmental, and public health and 

safety effects; distributive impacts; and 

equity). Executive Order 13563 

emphasized the importance of 

quantifying both costs and benefits, of 

reducing costs, of harmonizing rules, 

and of promoting flexibility. The full 

PEA has been placed in OSHA 

rulemaking docket OSHA–2010–0034. 

This rule is an economically significant 

regulatory action under Sec. 3(f)(1) of 

Executive Order 12866 and has been 

reviewed by the Office of Information 

and Regulatory Affairs in the Office of 

Management and Budget, as required by 

executive order. 

The purpose of the PEA is to: 

• Identify the establishments and 

industries potentially affected by the 

proposed rule; 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56337 

• Estimate current exposures and the 

technologically feasible methods of 

controlling these exposures; 

• Estimate the benefits resulting from 

employers coming into compliance with 

the proposed rule in terms of reductions 

in cases of silicosis, lung cancer, other 

forms of chronic obstructive pulmonary 

disease, and renal failure; 

• Evaluate the costs and economic 

impacts that establishments in the 

regulated community will incur to 

achieve compliance with the proposed 

rule; 

• Assess the economic feasibility of 

the proposed rule for affected 

industries; and 

• Assess the impact of the proposed 

rule on small entities through an Initial 

Regulatory Flexibility Analysis (IRFA), 

to include an evaluation of significant 

regulatory alternatives to the proposed 

rule that OSHA has considered. 

The Preliminary Economic Analysis 

contains the following chapters: 

Chapter I. Introduction 

Chapter II. Assessing the Need for Regulation 

Chapter III. Profile of Affected Industries 

Chapter IV. Technological Feasibility 

Chapter V. Costs of Compliance 

Chapter VI. Economic Impacts 

Chapter VII. Benefits and Net Benefits 

Chapter VIII. Regulatory Alternatives 

Chapter IX. Initial Regulatory Flexibility 

Analysis 

Chapter X. Environmental Impacts 

Key findings of these chapters are 

summarized below and in sections 

VIII.B through VIII.I of this PEA 

summary. 

Profile of Affected Industries 

The proposed rule would affect 

employers and employees in many 

different industries across the economy. 

As described in Section VIII.C and 

reported in Table VIII–3 of this 

preamble, OSHA estimates that a total of 

2.1 million employees in 550,000 

establishments and 533,000 firms 

(entities) are potentially at risk from 

exposure to respirable crystalline silica. 

This total includes 1.8 million 

employees in 477,000 establishments 

and 486,000 firms in the construction 

industry and 295,000 employees in 

56,000 establishments and 47,000 firms 

in general industry and maritime. 

Technological Feasibility 

As described in more detail in Section 

VIII.D of this preamble and in Chapter 

IV of the PEA, OSHA assessed, for all 

affected sectors, the current exposures 

and the technological feasibility of the 

proposed PEL of 50 mg/m3 and, for 

analytic purposes, an alternative PEL of 

25 mg/m3. 

Tables VIII–6 and VIII–7 in section 

VIII.D of this preamble summarize all 

the industry sectors and construction 

activities studied in the technological 

feasibility analysis and show how many 

operations within each can achieve 

levels of 50 mg/m3 through the 

implementation of engineering and 

work practice controls. The table also 

summarizes the overall feasibility 

finding for each industry sector or 

construction activity based on the 

number of feasible versus infeasible 

operations. For the general industry 

sector, OSHA has preliminarily 

concluded that the proposed PEL of 50 

mg/m3 is technologically feasible for all 

affected industries. For the construction 

activities, OSHA has determined that 

the proposed PEL of 50 mg/m3 is feasible 

in 10 out of 12 of the affected activities. 

Thus, OSHA preliminarily concludes 

that engineering and work practices will 

be sufficient to reduce and maintain 

silica exposures to the proposed PEL of 

50 mg/m3 or below in most operations 

most of the time in the affected 

industries. For those few operations 

within an industry or activity where the 

proposed PEL is not technologically 

feasible even when workers use 

recommended engineering and work 

practice controls (seven out of 108 

operations, see Tables VIII–6 and VIII– 

7), employers can supplement controls 

with respirators to achieve exposure 

levels at or below the proposed PEL. 

Based on the information presented in 

the technological feasibility analysis, 

the Agency believes that 50 mg/m3 is the 

lowest feasible PEL. An alternative PEL 

of 25 mg/m3 would not be feasible 

because the engineering and work 

practice controls identified to date will 

not be sufficient to consistently reduce 

exposures to levels below 25 mg/m3 in 

most operations most of the time. OSHA 

believes that an alternative PEL of 25 

mg/m3 would not be feasible for many 

industries, and that the use of 

respiratory protection would be 

necessary in most operations most of the 

time to achieve compliance. 

Additionally, the current methods of 

sampling analysis create higher errors 

and lower precision in measurement as 

concentrations of silica lower than the 

proposed PEL are analyzed. However, 

the Agency preliminarily concludes that 

these sampling and analytical methods 

are adequate to permit employers to 

comply with all applicable requirements 

triggered by the proposed action level 

and PEL. 

Costs of Compliance 

As described in more detail in Section 

VIII.E and reported by industry in Table 

VIII–8 of this preamble, the total 

annualized cost of compliance with the 

proposed standard is estimated to be 

about $658 million. The major cost 

elements associated with the revisions 

to the standard are costs for engineering 

controls, including controls for abrasive 

blasting ($344 million); medical 

surveillance ($79 million); exposure 

monitoring ($74 million); respiratory 

protection ($91 million); training ($50 

million) and regulated areas or access 

control ($19 million). Of the total cost, 

$511 million would be borne by firms 

in the construction industry and $147 

million would be borne by firms in 

general industry and maritime. 

The compliance costs are expressed as 

annualized costs in order to evaluate 

economic impacts against annual 

revenue and annual profits, to be able to 

compare the economic impact of the 

rulemaking with other OSHA regulatory 

actions, and to be able to add and track 

Federal regulatory compliance costs and 

economic impacts in a consistent 

manner. Annualized costs also represent 

a better measure for assessing the 

longer-term potential impacts of the 

rulemaking. The annualized costs were 

calculated by annualizing the one-time 

costs over a period of 10 years and 

applying discount rates of 7 and 3 

percent as appropriate. 

The estimated costs for the proposed 

silica standard rule include the 

additional costs necessary for employers 

to achieve full compliance. They do not 

include costs associated with current 

compliance that has already been 

achieved with regard to the new 

requirements or costs necessary to 

achieve compliance with existing silica 

requirements, to the extent that some 

employers may currently not be fully 

complying with applicable regulatory 

requirements. 

OSHA’s exposure profile represents 

the Agency’s best estimate of current 

exposures (i.e., baseline exposures). 

OSHA did not attempt to determine the 

extent to which current exposures in 

compliance with the current silica PELs 

are the result of baseline engineering 

controls or the result of circumstances 

leading to low exposures. This 

information is not needed to estimate 

the costs of (additional) engineering 

controls needed to comply with the 

proposed standard. 

Because of the severe health hazards 

involved, the Agency expects that the 

estimated 15,446 abrasive blasters in the 

construction sector and the estimated 

4,550 abrasive blasters in the maritime 

sector are currently wearing respirators 

in compliance with OSHA’s abrasive 

blasting provisions. Furthermore, for the 

construction baseline, an estimated 

241,269 workers, including abrasive 

blasters, will need to use respirators to 

achieve compliance with the proposed 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56338 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

rule, and, based on the NIOSH/BLS 

respirator use survey (NIOSH/BLS, 

2003), an estimated 56 percent of 

construction employers currently 

require such respiratory use and have 

respirator programs that meet OSHA’s 

respirator standard. OSHA has not taken 

any costs for employers and their 

workers currently in compliance with 

the respiratory provisions in the 

proposed rule. 

In addition, under both the general 

industry and construction baselines, an 

estimated 50 percent of employers have 

pre-existing training programs that 

address silica-related risks (as required 

under OSHA’s hazard communication 

standard) and partially satisfy the 

proposed rule’s training requirements 

(for costing purposes, estimated to 

satisfy 50 percent of the training 

requirements in the proposed rule). 

These employers will need fewer 

resources to achieve full compliance 

with the proposed rule than those 

employers without pre-existing training 

programs that address silica-related 

risks. 

Other than respiratory protection and 

worker training concerning silicarelated risks, OSHA did not assume 

baseline compliance with any ancillary 

provisions, even though some 

employers have reported that they do 

currently monitor silica exposure and 

some employers have reported 

conducting medical surveillance. 

Economic Impacts 

To assess the nature and magnitude of 

the economic impacts associated with 

compliance with the proposed rule, 

OSHA developed quantitative estimates 

of the potential economic impact of the 

new requirements on entities in each of 

the affected industry sectors. The 

estimated compliance costs were 

compared with industry revenues and 

profits to provide an assessment of the 

economic feasibility of complying with 

the revised standard and an evaluation 

of the potential economic impacts. 

As described in greater detail in 

Section VIII.F of this preamble, the costs 

of compliance with the proposed 

rulemaking are not large in relation to 

the corresponding annual financial 

flows associated with each of the 

affected industry sectors. The estimated 

annualized costs of compliance 

represent about 0.02 percent of annual 

revenues and about 0.5 percent of 

annual profits, on average, across all 

firms in general industry and maritime, 

and about 0.05 percent of annual 

revenues and about 1.0 percent of 

annual profits, on average, across all 

firms in construction. Compliance costs 

do not represent more than 0.39 percent 

of revenues or more than 8.8 percent of 

profits in any affected industry in 

general industry or maritime, or more 

than 0.13 percent of revenues or more 

than 3 percent of profits in any affected 

industry in construction. 

Based on its analysis of international 

trade effects, OSHA concluded that 

most or all costs arising from this 

proposed silica rule would be passed on 

in higher prices rather than absorbed in 

lost profits and that any price increases 

would result in minimal loss of business 

to foreign competition. 

Given the minimal potential impact 

on prices or profits in the affected 

industries, OSHA has preliminarily 

concluded that compliance with the 

requirements of the proposed 

rulemaking would be economically 

feasible in every affected industry 

sector. 

In addition, OSHA directed Inforum— 

a not-for-profit corporation with over 40 

years of experience in the design and 

application of macroeconomic models— 

to run its LIFT (Long-term Interindustry 

Forecasting Tool) model of the U.S. 

economy to estimate the industry and 

aggregate employment effects of the 

proposed silica rule. Inforum developed 

estimates of the employment impacts 

over the ten-year period from 2014– 

2023 by feeding OSHA’s year-by-year 

and industry-by-industry estimates of 

the compliance costs of the proposed 

rule into its LIFT model. The most 

important Inforum result is that the 

proposed silica rule would have a 

negligible—albeit slightly positive—net 

effect on aggregate U.S. employment. 

Based on its analysis of the costs and 

economic impacts associated with this 

rulemaking and on Inforum’s estimates 

of associated employment and other 

macroeconomic impacts, OSHA 

preliminarily concludes that the effect 

of the proposed standard on 

employment, wages, and economic 

growth for the United States would be 

negligible. 

Benefits, Net Benefits, and CostEffectiveness 

As described in more detail in Section 

VIII.G of this preamble, OSHA estimated 

the benefits, net benefits, and 

incremental benefits of the proposed 

silica rule. That section also contains a 

sensitivity analysis to show how robust 

the estimates of net benefits are to 

changes in various cost and benefit 

parameters. A full explanation of the 

derivation of the estimates presented 

there is provided in Chapter VII of the 

PEA for the proposed rule. OSHA 

invites comments on any aspect of its 

estimation of the benefits and net 

benefits of the proposed rule. 

OSHA estimated the benefits 

associated with the proposed PEL of 50 

mg/m3 and, for analytical purposes to 

comply with OMB Circular A–4, with 

an alternative PEL of 100 mg/m3 for 

respirable crystalline silica by applying 

the dose-response relationship 

developed in the Agency’s quantitative 

risk assessment—summarized in 

Section VI of this preamble—to current 

exposure levels. OSHA determined 

current exposure levels by first 

developing an exposure profile 

(presented in Chapter IV of the PEA) for 

industries with workers exposed to 

respirable crystalline silica, using OSHA 

inspection and site-visit data, and then 

applying this exposure profile to the 

total current worker population. The 

industry-by-industry exposure profile is 

summarized in Table VIII–5 in Section 

VIII.C of this preamble. 

By applying the dose-response 

relationship to estimates of current 

exposure levels across industries, it is 

possible to project the number of cases 

of the following diseases expected to 

occur in the worker population given 

current exposure levels (the ‘‘baseline’’): 

• Fatal cases of lung cancer, 

• fatal cases of non-malignant 

respiratory disease (including silicosis), 

• fatal cases of end-stage renal 

disease, and 

• cases of silicosis morbidity. 

Table VIII–1 provides a summary of 

OSHA’s best estimate of the costs and 

benefits of the proposed rule using a 

discount rate of 3 percent. As shown, 

the proposed rule is estimated to 

prevent 688 fatalities and 1,585 silicarelated illnesses annually once it is fully 

effective, and the estimated cost of the 

rule is $637 million annually. Also as 

shown in Table VIII–1, the discounted 

monetized benefits of the proposed rule 

are estimated to be $5.3 billion 

annually, and the proposed rule is 

estimated to generate net benefits of 

$4.6 billion annually. Table VIII–1 also 

presents the estimated costs and 

benefits of the proposed rule using a 

discount rate of 7 percent. The 

estimated costs and benefits of the 

proposed rule, disaggregated by 

industry sector, were previously 

presented in Table SI–3 in this 

preamble. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56339 

3An establishment is a single physical location at 

which business is conducted or services or 

industrial operations are performed. An entity is an 

aggregation of all establishments owned by a parent 

company within an industry with some annual 

payroll. 

4Production employment includes workers in 

building and grounds maintenance; forestry, 

fishing, and farming; installation and maintenance; 

construction; production; and material handling 

occupations. 

TABLE VIII–1—ANNUALIZED BENEFITS, COSTS AND NET BENEFITS OF OSHA’S PROPOSED SILICA STANDARD OF 50 μG/M3

Discount rate 3% 7% 

Annualized Costs 

Engineering Controls (includes Abrasive Blasting) .................................................. $329,994,068 $343,818,700 

Respirators ............................................................................................................... 90,573,449 90,918,741 

Exposure Assessment .............................................................................................. 72,504,999 74,421,757 

Medical Surveillance ................................................................................................. 76,233,932 79,069,527 

Training ..................................................................................................................... 48,779,433 50,266,744 

Regulated Area or Access Control ........................................................................... 19,243,500 19,396,743 

Total Annualized Costs (point estimate) ........................................................... 637,329,380 657,892,211 

Annual Benefits: Number of Cases Prevented 

Fatal Lung Cancers (midpoint estimate) .................................................................. 162 

Fatal Silicosis & other Non-Malignant Respiratory Diseases .................................. 375 

Fatal Renal Disease ................................................................................................. 151 

Silica-Related Mortality ............................................................................................. 688 3,203,485,869 2,101,980,475 

Silicosis Morbidity ..................................................................................................... 1,585 1,986,214,921 1,363,727,104 

Monetized Annual Benefits (midpoint estimate) ............................................... 5,189,700,790 3,465,707,579 

Net Benefits ....................................................................................................... 4,552,371,410 2,807,815,368 

Initial Regulatory Flexibility Analysis 

OSHA has prepared an Initial 

Regulatory Flexibility Analysis (IRFA) 

in accordance with the requirements of 

the Regulatory Flexibility Act, as 

amended in 1996. Among the contents 

of the IRFA are an analysis of the 

potential impact of the proposed rule on 

small entities and a description and 

discussion of significant alternatives to 

the proposed rule that OSHA has 

considered. The IRFA is presented in its 

entirety both in Chapter IX of the PEA 

and in Section VIII.I of this preamble. 

The remainder of this section (Section 

VIII) of the preamble is organized as 

follows: 

B. The Need for Regulation 

C. Profile of Affected Industry 

D. Technological Feasibility 

E. Costs of Compliance 

F. Economic Feasibility Analysis and 

Regulatory Flexibility Determination 

G. Benefits and Net Benefits 

H. Regulatory Alternatives 

I. Initial Regulatory Flexibility Analysis. 

B. Need for Regulation 

Employees in work environments 

addressed by the proposed silica rule 

are exposed to a variety of significant 

hazards that can and do cause serious 

injury and death. As described in 

Chapter II of the PEA in support of the 

proposed rule, the risks to employees 

are excessively large due to the 

existence of various types of market 

failure, and existing and alternative 

methods of overcoming these negative 

consequences—such as workers’ 

compensation systems, tort liability 

options, and information dissemination 

programs—have been shown to provide 

insufficient worker protection. 

After carefully weighing the various 

potential advantages and disadvantages 

of using a regulatory approach to 

improve upon the current situation, 

OSHA concludes that, in the case of 

silica exposure, the proposed mandatory 

standards represent the best choice for 

reducing the risks to employees. In 

addition, rulemaking is necessary in this 

case in order to replace older existing 

standards with updated, clear, and 

consistent health standards. 

C. Profile of Affected Industries 

1. Introduction 

Chapter III of the PEA presents profile 

data for industries potentially affected 

by the proposed silica rule. The 

discussion below summarizes the 

findings in that chapter. As a first step, 

OSHA identifies the North American 

Industrial Classification System 

(NAICS) industries, both in general 

industry and maritime and in the 

construction sector, with potential 

worker exposure to silica. Next, OSHA 

provides summary statistics for the 

affected industries, including the 

number of affected entities and 

establishments, the number of at-risk 

workers, and the average revenue for 

affected entities and establishments. 3

Finally, OSHA presents silica exposure 

profiles for at-risk workers. These data 

are presented by sector and job category. 

Summary data are also provided for the 

number of workers in each affected 

industry who are currently exposed 

above the proposed silica PEL of 50 mg/ 

m3, as well as above an alternative PEL 

of 100 mg/m3 for economic analysis 

purposes. 

The methodological basis for the 

industry and at-risk worker data 

presented here comes from ERG (2007a, 

2007b, 2008a, and 2008b). The actual 

data presented here comes from the 

technological feasibility analyses 

presented in Chapter IV of the PEA and 

from ERG (2013), which updated ERG’s 

earlier spreadsheets to reflect the most 

recent industry data available. The 

technological feasibility analyses 

identified the job categories with 

potential worker exposure to silica. ERG 

(2007a, 2007b) matched the BLS 

Occupational Employment Survey 

(OES) occupational titles in NAICS 

industries with the at-risk job categories 

and then calculated the percentages of 

production employment represented by 

each at-risk job title.4 These percentages 

were then used to project the number of 

employees in the at-risk job categories 

by NAICS industry. OSHA welcomes 

additional information and data that 

might help improve the accuracy and 

usefulness of the industry profile 

presented here and in Chapter III of the 

PEA. 

2. Selection of NAICS Industries for 

Analysis 

The technological feasibility analyses 

presented in Chapter IV of the PEA 

identify the general industry and 

maritime sectors and the construction 

activities potentially affected by the 

proposed silica standard. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56340 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

5Captive foundries include establishments in 

other industries with foundry processes incidental 

to the primary products manufactured. ERG (2008b) 

provides a discussion of the methodological issues 

involved in estimating the number of captive 

foundries and in identifying the industries in which 

they are found. 

a. General Industry and Maritime 

Employees engaged in various 

activities in general industry and 

maritime routinely encounter crystalline 

silica as a molding material, as an inert 

mineral additive, as a refractory 

material, as a sandblasting abrasive, or 

as a natural component of the base 

materials with which they work. Some 

industries use various forms of silica for 

multiple purposes. As a result, 

employers are challenged to limit 

worker exposure to silica in dozens of 

job categories throughout the general 

industry and maritime sectors. 

Job categories in general industry and 

maritime were selected for analysis 

based on data from the technical 

industrial hygiene literature, evidence 

from OSHA Special Emphasis Program 

(SEP) results, and, in several cases, 

information from ERG site visit reports. 

These data sources provided evidence of 

silica exposures in numerous sectors. 

While the available data are not entirely 

comprehensive, OSHA believes that 

silica exposures in other sectors are 

quite limited. 

The 25 industry subsectors in the 

overall general industry and maritime 

sectors that OSHA identified as being 

potentially affected by the proposed 

silica standard are as follows: 

• Asphalt Paving Products 

• Asphalt Roofing Materials 

• Industries with Captive Foundries 

• Concrete Products 

• Cut Stone 

• Dental Equipment and Supplies 

• Dental Laboratories 

• Flat Glass 

• Iron Foundries 

• Jewelry 

• Mineral Processing 

• Mineral Wool 

• Nonferrous Sand Casting Foundries 

• Non-Sand Casting Foundries 

• Other Ferrous Sand Casting Foundries 

• Other Glass Products 

• Paint and Coatings 

• Porcelain Enameling 

• Pottery 

• Railroads 

• Ready-Mix Concrete 

• Refractories 

• Refractory Repair 

• Shipyards 

• Structural Clay 

In some cases, affected industries 

presented in the technological 

feasibility analysis have been 

disaggregated to facilitate the cost and 

economic impact analysis. In particular, 

flat glass, mineral wool, and other glass 

products are subsectors of the glass 

industry described in Chapter IV of the 

PEA, and captive foundries,5 iron 

foundries, nonferrous sand casting 

foundries, non-sand cast foundries, and 

other ferrous sand casting foundries are 

subsectors of the overall foundries 

industry presented in Chapter IV of the 

PEA. 

As described in ERG (2008b), OSHA 

identified the six-digit NAICS codes for 

these subsectors to develop a list of 

industries potentially affected by the 

proposed silica standard. Table VIII–2 

presents the sectors listed above with 

their corresponding six-digit NAICS 

industries. 

BILLING CODE 4510–26–P 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56341 


mstockstill on DSK4VPTVN1PROD with PROPOSALS2EP12SE13.004</GPH>

Table VIII-2 

General Industry and Martime Sectors and Industries Potentially Affected by OSHA's Proposed Silica Rule 

Sector 

Asphalt Paving Products 

Asphalt Roofing Materials 

Captive Foundries 

NAICS 

324121 

324122 

331111 

331112 

331210 

331221 

331222 

331314 

331423 

331492 

332111 

332112 

332115 

332116 

332117 

332211 

332212 

332213 

332214 

332439 

332510 

332611 

332612 

332618 

332710 

332911 

332912 

332913 

332919 

332991 

332996 

332997 

332998 

332999 

333319 

333411 

333412 

333414 

333511 

333512 

333513 

333514 

333515 

333516 

333518 

333612 

333613 

333911 

333912 

333991 

333992 

333993 

333994 

333995 

333996 

333997 

333999 

334518 

336111 

336112 

336120 

336211 

336212 

Industry 

Asphalt paving mixture and block mfg 

Asphalt shingle and roofing materials 

Iron & steel mills 

Electrometallurgical ferroalloy product mfg 

Iron & steel pipes & tubes mfg from purchased steel 

Cold-rolled steel shape mfg 

Steel wire drawing 

Secondary smelting & alloying of aluminum 

Secondary smelting, refining, & alloying of copper 

Other nonferrous metal secondary smelting, refining, & alloying 

Iron & steel forging 

Nonferrous forging 

Crown & closure mfg 

Metal stamping 

Powder metallurgy part mfg 

Cutlery & flatware (except precious) mfg 

Hand & edge tool mfg 

Saw blade & handsaw mfg 

Kitchen utensil, pot, & pan mfg 

Other metal container mfg 

Hardware mfg 

Spring (heavy gauge) mfg 

Spring (light gauge) mfg 

Other fabricated wire product mfg 

Machine shops 

Industrial valve mfg 

Fluid power valve & hose fitting mfg 

Plumbing fixture fitting & trim mfg 

Other metal valve & pipe fitting mfg 

Ball & roller bearing mfg 

Fabricated pipe & pipe fitting mfg 

Industrial pattern mfg 

Enameled iron & metal sanitary ware mfg 

All other miscellaneous fabricated metal product mfg 

Other commercial & service industry machinery mfg 

Air purification equipment mfg 

Industrial & commercial fan & blower mfg 

Heating equipment (except warm air furnaces) mfg 

Industrial mold mfg 

Machine tool (metal cutting types) mfg 

Machine tool (metal forming types) mfg 

Special die & tool, die set, jig, & fixture mfg 

Cutting tool & machine tool accessory mfg 

Rolling mill machinery & equipment mfg 

Other metalworking machinery mfg 

Speed changer, industrial high-speed drive, & gear mfg 

Mechanical power transmission equipment mfg 

Pump & pumping equipment mfg 

Air & gas compressor mfg 

Power-driven handtool mfg 

Welding & soldering equipment mfg 

Packaging machinery mfg 

Industrial process furnace & oven mfg 

Fluid power cylinder & actuator mfg 

Fluid power pump & motor mfg 

Scale & balance (except laboratory) mfg 

All other miscellaneous general-purpose machinery mfg 

Watch, clock, & part mfg 

Automobile mfg 

Light truck & utility vehicle mfg 

Heavy duty truck mfg 

Motor vehicle body mfg 

Truck trailer mfg 
56342 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

BILLING CODE 4510–26–C 


mstockstill on DSK4VPTVN1PROD with PROPOSALS2EP12SE13.005</GPH>

Table VIII-2 

General Industry and Martime Sectors and Industries Potentially Affected by OSHA's Proposed Silica Rule 

(Continued) 

Concrete Products 

Cut Stone 

Dental Equipment and Supplies 

Dental Laboratories 

Flat Glass 

Iron Foundries 

Jewelry 

Mineral Processing 

Mineral Wool 

Nonferrous Sand Casting Foundries 

Non-Sand Casting Foundries 

Other Ferrous Sand Casting Foundries 

Other Glass Products 

Paint and Coatings 

Porcelain Enameling 

Pottery 

Railraods 

Ready-Mix Concrete 

Refractories 

Refractory Repair 

Shipyards 

Structural Clay 

Source: ERG, 2013 

336311 

336312 

336322 

336330 

336340 

336350 

336370 

336399 

336992 

337215 

339914 

327331 

327332 

327390 

327999 

327991 

339114 

339116 

Carburetor, piston, piston ring, & vallA3 mfg 

Gasoline engine & engine parts mfg 

Other motor IA3hicle electrical & electronic equipment mfg 

Motor IA3hicle steering & suspension component (except spring) mfg 

Motor IA3hicie brake system mfg 

Motor IA3hicie transmission & power train parts mfg 

Motor IA3hicie metal stamping 

All other motor IA3hicie parts mfg 

Military armored IA3hicle, tank, & tank component mfg 

Showcase, partition, shellhng, & locker mfg 

Costume jewelry & nOlA3lty mfg 

Concrete block & brick mfg 

Concrete pipe mfg 

Other concrete product mfg 

All other miscellaneous nonmetallic mineral product mfg 

Cut stone & stone product mfg 

Dental equipment and supplies, manufacturing 

Dental laboratories 

621210 Offices of dentists 

327211 Flat glass mfg 

331511 Iron foundries 

339911 Jewelry (except costume) mfg 

339913 Jewelers' material & lapidary work mfg 

339914 Costume jewelry & nOlA3lty mfg 

327992 Ground or treated mineral and earth manufacturing 

327993 Mineral wool mfg 

331524 Aluminum foundries (except die-casting) 

331525 Copper foundries (except die-casting) 

331528 Other nonferrous foundries (except die-casting) 

331512 Steel inlA3stment foundries 

331524 Aluminum foundries (except die-casting) 

331525 Copper foundries (except die-casting) 

331528 Other nonferrous foundries (except die-casting) 

331513 Steel foundries (except inlA3stment) 

327212 Other pressed & blown glass & glassware mfg 

327213 Glass container mfg 

325510 Paint & coating mfg tel 

332812 Metal coating and allied serlhces 

332998 Enameled iron & metal sanitary ware mfg 

335211 Electric housewares and household fans 

335221 Household cooking appliance manufactruing 

335222 Household refrigerator and home freezer manufacturing 

332323 Ornamental and architectural metal work 

335224 Household laundry equipment manufacturing 

335228 Other major household appliance manufacturing 

339950 Sign manufacturing 

327111 Vitreous china plumbing fixture & bathroom accessories mfg 

327112 Vitreous china, fine earthenware, & other pottery product mfg 

327113 Porcelain electrical supply mfg 

482110 Rail transportation 

327320 Ready-mix concrete mfg 

327124 Clay refractory mfg 

327125 Nonclay refractory mfg 

423840 Industrial supplies - wholesale 

336611 Ship building & repairing 

336612 Boat building 

327121 Brick & structural clay tile mfg 

327122 Ceramic wall & floor tile mfg 

327123 Other structural clay product mfg 
Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56343 

6ERG and OSHA used the four-digit NAICS codes 

for the construction sector both because the BLS’s 

Occupational Employment Statistics survey only 

provides data at this level of detail and because, 

unlike the case in general industry and maritime, 

job categories in the construction sector are taskspecific, not industry-specific. Furthermore, as far 

as economic impacts are concerned, IRS data on 

profitability are reported only at the four-digit 

NAICS code level of detail. 

7 In addition, some public employees in state and 

local governments are exposed to elevated levels of 

respirable crystalline silica. These exposures are 

included in the construction sector because they are 

the result of construction activities. 

8OSHA determined that removing this 

assumption would have a negligible impact on total 

costs and would reduce the cost and economic 

impact on the average affected establishment or 

entity. 

b. Construction 

The construction sector is an integral 

part of the nation’s economy, 

accounting for almost 6 percent of total 

employment. Establishments in this 

industry are involved in a wide variety 

of activities, including land 

development and subdivision, 

homebuilding, construction of 

nonresidential buildings and other 

structures, heavy construction work 

(including roadways and bridges), and a 

myriad of special trades such as 

plumbing, roofing, electrical, 

excavation, and demolition work. 

Construction activities were selected 

for analysis based on historical data of 

recorded samples of construction 

worker exposures from the OSHA 

Integrated Management Information 

System (IMIS) and the National Institute 

for Occupational Safety and Health 

(NIOSH). In addition, OSHA reviewed 

the industrial hygiene literature across 

the full range of construction activities, 

and focused on dusty operations where 

silica sand was most likely to be 

fractured or abraded by work 

operations. These physical processes 

have been found to cause the silica 

exposures that pose the greatest risk of 

silicosis for workers. 

The 12 construction activities, by job 

category, that OSHA identified as being 

potentially affected by the proposed 

silica standard are as follows: 

• Abrasive Blasters 

• Drywall Finishers 

• Heavy Equipment Operators 

• Hole Drillers Using Hand-Held Drills 

• Jackhammer and Impact Drillers 

• Masonry Cutters Using Portable Saws 

• Masonry Cutters Using Stationary 

Saws 

• Millers Using Portable or Mobile 

Machines 

• Rock and Concrete Drillers 

• Rock-Crushing Machine Operators 

and Tenders 

• Tuckpointers and Grinders 

• Underground Construction Workers 

As shown in ERG (2008a) and in 

Chapter IV of the PEA, these 

construction activities occur in the 

following construction industries, 

accompanied by their four-digit NAICS 

codes: 6 7

• 2361 Residential Building 

Construction 

• 2362 Nonresidential Building 

Construction 

• 2371 Utility System Construction 

• 2372 Land Subdivision 

• 2373 Highway, Street, and Bridge 

Construction 

• 2379 Other Heavy and Civil 

Engineering Construction 

• 2381 Foundation, Structure, and 

Building Exterior Contractors 

• 2382 Building Equipment Contractors 

• 2383 Building Finishing Contractors 

• 2389 Other Specialty Trade 

Contractors 

Characteristics of Affected Industries 

Table VIII–3 provides an overview of 

the industries and estimated number of 

workers affected by the proposed rule. 

Included in Table VIII–3 are summary 

statistics for each of the affected 

industries, subtotals for construction 

and for general industry and maritime, 

and grand totals for all affected 

industries combined. 

The first five columns in Table VIII– 

3 identify each industry in which 

workers are routinely exposed to 

respirable crystalline silica (preceded by 

the industry’s NAICS code) and the total 

number of entities, establishments, and 

employees for that industry. Note that 

not all entities, establishments, and 

employees in these affected industries 

necessarily engage in activities 

involving silica exposure. 

The next three columns in Table VIII– 

3 show, for each affected industry, 

OSHA’s estimate of the number of 

affected entities, establishments, and 

workers—that is, the number of entities 

and establishments in which workers 

are actually exposed to silica and the 

total number of workers exposed to 

silica. Based on ERG (2007a, 2007b), 

OSHA’s methodology focused on 

estimation of the number of affected 

workers. The number of affected 

establishments was set equal to the total 

number of establishments in an industry 

(based on Census data) unless the 

number of affected establishments 

would exceed the number of affected 

employees in the industry. In that case, 

the number of affected establishments in 

the industry was set equal to the 

number of affected employees, and the 

number of affected entities in the 

industry was reduced so as to maintain 

the same ratio of entities to 

establishments in the industry.8

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56344 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–3—CHARACTERISTICS OF INDUSTRIES

AFFECTED BY OSHA’

S

PROPOSED

STANDARD FOR

SILICA—ALL

ENTITIES

NAICS Industry Total entities a Total estab- lish-ments a Total employ- ment a Total affected entities b Total affected establish- ments b Total affected employment b Total FTE affected employees b Total revenues ($1,000) c Revenues per entity Revenues per establishment 

Construction 

236100 ........ Residential Building Construction ............................................. 197,600 198,912 966,198 54,973 55,338 55,338 27,669 $374,724,410 $1,896,379 $1,883,870 236200 ........ Nonresidential Building Construction ....................................... 43,634 44,702 741,978 43,634 44,702 173,939 34,788 313,592,140 7,186,876 7,015,170 237100 ........ Utility System Construction ...................................................... 20,236 21,232 496,628 20,236 21,232 217,070 96,181 98,129,343 4,849,246 4,621,766 237200 ........ Land Subdivision ...................................................................... 12,383 12,469 77,406 6,466 6,511 6,511 3,255 24,449,519 1,974,442 1,960,824 237300 ........ Highway, Street, and Bridge Construction ............................... 11,081 11,860 325,182 11,081 11,860 204,899 66,916 96,655,241 8,722,610 8,149,683 237900 ........ Other Heavy and Civil Engineering Construction .................... 5,326 5,561 90,167 5,326 5,561 46,813 18,835 19,456,230 3,653,066 3,498,693 238100 ........ Foundation, Structure, and Building Exterior Contractors ....... 116,836 117,456 1,167,986 116,836 117,456 559,729 111,946 157,513,197 1,348,156 1,341,040 238200 ........ Building Equipment Contractors ............................................... 179,051 182,368 1,940,281 19,988 20,358 20,358 10,179 267,537,377 1,494,196 1,467,019 238300 ........ Building Finishing Contractors .................................................. 132,219 133,343 975,335 119,000 120,012 120,012 60,006 112,005,298 847,120 839,979 238900 ........ Other Specialty Trade Contractors ........................................... 73,922 74,446 557,638 73,922 74,446 274,439 137,219 84,184,953 1,138,835 1,130,819 999000 ........ State and local governments d ................................................. 14,397 N/A 5,762,939 14,397 NA 170,068 85,034 N/A N/A N/A 

Subtotals—Construction .................................................... 806,685 802,349 13,101,738 485,859 477,476 1,849,175 652,029 1,548,247,709 1,954,148 1,929,644 

General Industry and Maritime 

324121 ........ Asphalt paving mixture and block manufacturing .................... 480 1,431 14,471 480 1,431 5,043 ........................ 8,909,030 18,560,480 6,225,737 324122 ........ Asphalt shingle and roofing materials ...................................... 121 224 12,631 121 224 4,395 ........................ 7,168,591 59,244,556 32,002,640 325510 ........ Paint and coating manufacturing e ........................................... 1,093 1,344 46,209 1,093 1,344 3,285 ........................ 24,113,682 22,061,923 17,941,728 327111 ........ Vitreous china plumbing fixtures & bathroom accessories 

manufacturing.

31 41 5,854 31 41 2,802 ........................ 818,725 26,410,479 19,968,899 

327112 ........ Vitreous china, fine earthenware, & other pottery product 

manufacturing.

728 731 9,178 728 731 4,394 ........................ 827,296 1,136,395 1,131,731 

327113 ........ Porcelain electrical supply mfg ................................................. 110 125 6,168 110 125 2,953 ........................ 951,475 8,649,776 7,611,802 327121 ........ Brick and structural clay mfg .................................................... 104 204 13,509 104 204 5,132 ........................ 2,195,641 21,111,931 10,762,945 327122 ........ Ceramic wall and floor tile mfg ................................................. 180 193 7,094 180 193 2,695 ........................ 1,217,597 6,764,429 6,308,794 327123 ........ Other structural clay product mfg ............................................. 45 49 1,603 45 49 609 ........................ 227,406 5,053,461 4,640,933 327124 ........ Clay refractory manufacturing .................................................. 108 129 4,475 108 129 1,646 ........................ 955,377 8,846,082 7,406,022 327125 ........ Nonclay refractory manufacturing ............................................ 81 105 5,640 81 105 2,075 ........................ 1,453,869 17,948,999 13,846,371 327211 ........ Flat glass manufacturing .......................................................... 56 83 11,003 56 83 271 ........................ 3,421,674 61,101,328 41,224,993 327212 ........ Other pressed and blown glass and glassware manufacturing 457 499 20,625 457 499 1,034 ........................ 3,395,635 7,430,274 6,804,880 327213 ........ Glass container manufacturing ................................................. 32 72 14,392 32 72 722 ........................ 4,365,673 136,427,289 60,634,351 327320 ........ Ready-mixed concrete manufacturing ...................................... 2,470 6,064 107,190 2,470 6,064 43,920 ........................ 27,904,708 11,297,453 4,601,700 327331 ........ Concrete block and brick mfg .................................................. 599 951 22,738 599 951 10,962 ........................ 5,127,518 8,560,131 5,391,712 327332 ........ Concrete pipe mfg .................................................................... 194 385 14,077 194 385 6,787 ........................ 2,861,038 14,747,620 7,431,268 327390 ........ Other concrete product mfg ..................................................... 1,934 2,281 66,095 1,934 2,281 31,865 ........................ 10,336,178 5,344,456 4,531,424 327991 ........ Cut stone and stone product manufacturing ............................ 1,885 1,943 30,633 1,885 1,943 12,085 ........................ 3,507,209 1,860,588 1,805,048 327992 ........ Ground or treated mineral and earth manufacturing ............... 171 271 6,629 171 271 5,051 ........................ 2,205,910 12,900,061 8,139,891 327993 ........ Mineral wool manufacturing ..................................................... 195 321 19,241 195 321 1,090 ........................ 5,734,226 29,406,287 17,863,633 327999 ........ All other misc. nonmetallic mineral product mfg ...................... 350 465 10,028 350 465 4,835 ........................ 2,538,560 7,253,028 5,459,268 331111 ........ Iron and steel mills ................................................................... 686 805 108,592 523 614 614 ........................ 53,496,748 77,983,597 66,455,587 331112 ........ Electrometallurgical ferroalloy product manufacturing ............. 22 22 2,198 12 12 12 ........................ 1,027,769 46,716,774 46,716,774 331210 ........ Iron and steel pipe and tube manufacturing from purchased 

steel.

186 240 21,543 94 122 122 ........................ 7,014,894 37,714,484 29,228,725 

331221 ........ Rolled steel shape manufacturing ............................................ 150 170 10,857 54 61 61 ........................ 4,494,254 29,961,696 26,436,790 331222 ........ Steel wire drawing .................................................................... 232 288 14,669 67 83 83 ........................ 3,496,143 15,069,584 12,139,387 331314 ........ Secondary smelting and alloying of aluminum ........................ 119 150 7,381 33 42 42 ........................ 4,139,263 34,783,724 27,595,088 331423 ........ Secondary smelting, refining, and alloying of copper .............. 29 31 1,278 7 7 7 ........................ 765,196 26,386,082 24,683,755 331492 ........ Secondary smelting, refining, and alloying of nonferrous 

metal (except cu & al).

195 217 9,383 48 53 53 ........................ 3,012,985 15,451,203 13,884,721 

331511 ........ Iron foundries ............................................................................ 457 527 59,209 457 527 22,111 ........................ 9,753,093 21,341,560 18,506,818 331512 ........ Steel investment foundries ....................................................... 115 132 16,429 115 132 5,934 ........................ 2,290,472 19,917,147 17,352,060 331513 ........ Steel foundries (except investment) ......................................... 208 222 17,722 208 222 6,618 ........................ 3,640,441 17,502,121 16,398,383 331524 ........ Aluminum foundries (except die-casting) ................................. 441 466 26,565 441 466 9,633 ........................ 3,614,233 8,195,541 7,755,866 331525 ........ Copper foundries (except die-casting) ..................................... 251 256 6,120 251 256 2,219 ........................ 747,437 2,977,835 2,919,674 331528 ........ Other nonferrous foundries (except die-casting) ...................... 119 124 4,710 119 124 1,708 ........................ 821,327 6,901,910 6,623,607 332111 ........ Iron and steel forging ............................................................... 358 398 26,596 135 150 150 ........................ 5,702,872 15,929,811 14,328,825 332112 ........ Nonferrous forging .................................................................... 67 77 8,814 43 50 50 ........................ 2,080,000 31,044,783 27,012,993 332115 ........ Crown and closure manufacturing ........................................... 50 59 3,243 15 18 18 ........................ 905,206 18,104,119 15,342,473 332116 ........ Metal stamping ......................................................................... 1,556 1,641 64,724 347 366 366 ........................ 10,418,233 6,695,523 6,348,710 332117 ........ Powder metallurgy part manufacturing .................................... 111 129 8,362 41 47 47 ........................ 1,178,698 10,618,900 9,137,193 332211 ........ Cutlery and flatware (except precious) manufacturing ............ 138 141 5,779 32 33 33 ........................ 1,198,675 8,686,049 8,501,240 332212 ........ Hand and edge tool manufacturing .......................................... 1,056 1,155 36,622 189 207 207 ........................ 6,382,593 6,044,123 5,526,055 332213 ........ Saw blade and handsaw manufacturing .................................. 127 136 7,304 39 41 41 ........................ 1,450,781 11,423,474 10,667,509 332214 ........ Kitchen utensil, pot, and pan manufacturing ............................ 64 70 3,928 20 22 22 ........................ 1,226,230 19,159,850 17,517,577 332323 ........ Ornamental and architectural metal work ................................ 2,408 2,450 39,947 53 54 54 ........................ 6,402,565 2,658,873 2,613,292 332439 ........ Other metal container manufacturing ....................................... 364 401 15,195 78 86 86 ........................ 2,817,120 7,739,340 7,025,236 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56345 

332510 ........ Hardware manufacturing .......................................................... 734 828 45,282 227 256 256 ........................ 9,268,800 12,627,793 11,194,203 332611 ........ Spring (heavy gauge) manufacturing ....................................... 109 113 4,059 22 23 23 ........................ 825,444 7,572,882 7,304,815 332612 ........ Spring (light gauge) manufacturing .......................................... 270 340 15,336 69 87 87 ........................ 2,618,283 9,697,344 7,700,832 332618 ........ Other fabricated wire product manufacturing ........................... 1,103 1,198 36,364 189 205 205 ........................ 5,770,701 5,231,823 4,816,946 332710 ........ Machine shops ......................................................................... 21,135 21,356 266,597 1,490 1,506 1,506 ........................ 32,643,382 1,544,518 1,528,534 332812 ........ Metal coating and allied services ............................................. 2,363 2,599 56,978 2,363 2,599 4,695 ........................ 11,010,624 4,659,595 4,236,485 332911 ........ Industrial valve manufacturing .................................................. 394 488 38,330 175 216 216 ........................ 8,446,768 21,438,497 17,308,951 332912 ........ Fluid power valve and hose fitting manufacturing ................... 306 381 35,519 161 201 201 ........................ 8,044,008 26,287,608 21,112,882 332913 ........ Plumbing fixture fitting and trim manufacturing ........................ 126 144 11,513 57 65 65 ........................ 3,276,413 26,003,281 22,752,871 332919 ........ Other metal valve and pipe fitting manufacturing .................... 240 268 18,112 91 102 102 ........................ 3,787,626 15,781,773 14,132,931 332991 ........ Ball and roller bearing manufacturing ...................................... 107 180 27,197 91 154 154 ........................ 6,198,871 57,933,374 34,438,172 332996 ........ Fabricated pipe and pipe fitting manufacturing ........................ 711 765 27,201 143 154 154 ........................ 4,879,023 6,862,198 6,377,808 332997 ........ Industrial pattern manufacturing ............................................... 459 461 5,281 30 30 30 ........................ 486,947 1,060,887 1,056,285 332998 ........ Enameled iron and metal sanitary ware manufacturing .......... 72 76 5,655 72 76 96 ........................ 1,036,508 14,395,940 13,638,259 332999 ........ All other miscellaneous fabricated metal product manufacturing. 3,043 3,123 72,201 397 408 408 ........................ 12,944,345 4,253,811 4,144,843 333319 ........ Other commercial and service industry machinery manufacturing. 1,253 1,349 53,012 278 299 299 ........................ 12,744,730 10,171,373 9,447,539 333411 ........ Air purification equipment manufacturing ................................. 303 351 14,883 72 84 84 ........................ 2,428,159 8,013,727 6,917,833 333412 ........ Industrial and commercial fan and blower manufacturing ....... 142 163 10,506 52 59 59 ........................ 1,962,040 13,817,181 12,037,053 333414 ........ Heating equipment (except warm air furnaces) manufacturing 377 407 20,577 108 116 116 ........................ 4,266,536 11,317,071 10,482,888 333511 ........ Industrial mold manufacturing .................................................. 2,084 2,126 39,917 221 226 226 ........................ 4,963,915 2,381,917 2,334,861 333512 ........ Machine tool (metal cutting types) manufacturing ................... 514 530 17,220 94 97 97 ........................ 3,675,264 7,150,320 6,934,461 333513 ........ Machine tool (metal forming types) manufacturing .................. 274 285 8,556 46 48 48 ........................ 1,398,993 5,105,812 4,908,746 333514 ........ Special die and tool, die set, jig, and fixture manufacturing .... 3,172 3,232 57,576 319 325 325 ........................ 7,232,706 2,280,172 2,237,842 333515 ........ Cutting tool and machine tool accessory manufacturing ......... 1,482 1,552 34,922 188 197 197 ........................ 4,941,932 3,334,637 3,184,235 333516 ........ Rolling mill machinery and equipment manufacturing ............. 70 73 3,020 17 17 17 ........................ 652,141 9,316,299 8,933,437 333518 ........ Other metalworking machinery manufacturing ......................... 362 383 12,470 67 70 70 ........................ 2,605,582 7,197,740 6,803,086 333612 ........ Speed changer, industrial high-speed drive, and gear manufacturing. 197 226 12,374 61 70 70 ........................ 2,280,825 11,577,790 10,092,145 333613 ........ Mechanical power transmission equipment manufacturing ..... 196 231 15,645 75 88 88 ........................ 3,256,010 16,612,294 14,095,280 333911 ........ Pump and pumping equipment manufacturing ........................ 413 490 30,764 147 174 174 ........................ 7,872,517 19,061,785 16,066,362 333912 ........ Air and gas compressor manufacturing ................................... 272 318 21,417 104 121 121 ........................ 6,305,944 23,183,616 19,830,011 333991 ........ Power-driven handtool manufacturing ...................................... 137 150 8,714 45 49 49 ........................ 3,115,514 22,740,979 20,770,094 333992 ........ Welding and soldering equipment manufacturing .................... 250 275 15,853 82 90 90 ........................ 4,257,678 17,030,713 15,482,466 333993 ........ Packaging machinery manufacturing ....................................... 583 619 21,179 113 120 120 ........................ 4,294,579 7,366,345 6,937,931 333994 ........ Industrial process furnace and oven manufacturing ................ 312 335 10,720 56 61 61 ........................ 1,759,938 5,640,828 5,253,548 333995 ........ Fluid power cylinder and actuator manufacturing .................... 269 319 19,887 95 112 112 ........................ 3,991,832 14,839,523 12,513,579 333996 ........ Fluid power pump and motor manufacturing ........................... 146 178 13,631 63 77 77 ........................ 3,019,188 20,679,367 16,961,728 333997 ........ Scale and balance (except laboratory) manufacturing ............ 95 102 3,748 20 21 21 ........................ 694,419 7,309,671 6,808,027 333999 ........ All other miscellaneous general purpose machinery manufacturing. 1,630 1,725 52,454 280 296 296 ........................ 9,791,511 6,007,062 5,676,238 334518 ........ Watch, clock, and part manufacturing ...................................... 104 106 2,188 12 12 12 ........................ 491,114 4,722,250 4,633,151 335211 ........ Electric housewares and household fans ................................ 99 105 7,425 20 22 22 ........................ 2,175,398 21,973,717 20,718,076 335221 ........ Household cooking appliance manufacturing .......................... 116 125 16,033 43 47 47 ........................ 4,461,008 38,456,968 35,688,066 335222 ........ Household refrigerator and home freezer manufacturing ........ 18 26 17,121 18 26 50 ........................ 4,601,594 255,644,105 176,984,380 335224 ........ Household laundry equipment manufacturing .......................... 17 23 16,269 17 23 47 ........................ 4,792,444 281,908,445 208,367,112 335228 ........ Other major household appliance manufacturing .................... 39 45 12,806 32 37 37 ........................ 4,549,859 116,663,058 101,107,984 336111 ........ Automobile manufacturing ........................................................ 167 181 75,225 167 181 425 ........................ 87,308,106 522,803,033 482,365,229 336112 ........ Light truck and utility vehicle manufacturing ............................ 63 94 103,815 63 94 587 ........................ 139,827,543 2,219,484,812 1,487,527,055 336120 ........ Heavy duty truck manufacturing ............................................... 77 95 32,122 77 95 181 ........................ 17,387,065 225,806,042 183,021,739 336211 ........ Motor vehicle body manufacturing ........................................... 728 820 47,566 239 269 269 ........................ 11,581,029 15,908,007 14,123,206 336212 ........ Truck trailer manufacturing ....................................................... 353 394 32,260 163 182 182 ........................ 6,313,133 17,884,229 16,023,179 336213 ........ Motor home manufacturing ...................................................... 79 91 21,533 79 91 122 ........................ 5,600,569 70,893,283 61,544,718 336311 ........ Carburetor, piston, piston ring, and valve manufacturing ........ 102 116 10,537 52 60 60 ........................ 2,327,226 22,815,945 20,062,296 336312 ........ Gasoline engine and engine parts manufacturing ................... 810 876 66,112 345 373 373 ........................ 30,440,351 37,580,680 34,749,259 336322 ........ Other motor vehicle electrical and electronic equipment manufacturing. 643 697 62,016 323 350 350 ........................ 22,222,133 34,560,082 31,882,544 336330 ........ Motor vehicle steering and suspension components (except 

spring) manufacturing.

214 257 39,390 185 223 223 ........................ 10,244,934 47,873,524 39,863,557 

336340 ........ Motor vehicle brake system manufacturing ............................. 188 241 33,782 149 191 191 ........................ 11,675,801 62,105,323 48,447,306 336350 ........ Motor vehicle transmission and power train parts manufacturing. 432 535 83,756 382 473 473 ........................ 31,710,273 73,403,409 59,271,538 336370 ........ Motor vehicle metal stamping .................................................. 635 781 110,578 508 624 624 ........................ 24,461,822 38,522,554 31,321,154 336399 ........ All other motor vehicle parts manufacturing ............................ 1,189 1,458 149,251 687 843 843 ........................ 42,936,991 36,111,851 29,449,239 336611 ........ Ship building and repair ........................................................... 575 635 87,352 575 635 2,798 ........................ 14,650,189 25,478,589 23,071,163 336612 ........ Boat building ............................................................................. 1,066 1,129 54,705 1,066 1,129 1,752 ........................ 10,062,908 9,439,876 8,913,116 336992 ........ Military armored vehicle, tank, and tank component manufacturing. 47 57 6,899 32 39 39 ........................ 2,406,966 51,212,047 42,227,477 337215 ........ Showcase, partition, shelving, and locker manufacturing ........ 1,647 1,733 59,080 317 334 334 ........................ 8,059,533 4,893,462 4,650,625 339114 ........ Dental equipment and supplies manufacturing ........................ 740 763 15,550 399 411 411 ........................ 3,397,252 4,590,881 4,452,493 339116 ........ Dental laboratories ................................................................... 7,028 7,261 47,088 7,028 7,261 33,214 ........................ 3,852,293 548,135 530,546 339911 ........ Jewelry (except costume) manufacturing ................................. 1,760 1,777 25,280 1,760 1,777 7,813 ........................ 6,160,238 3,500,135 3,466,650 339913 ........ Jewelers’ materials and lapidary work manufacturing ............. 261 264 5,199 261 264 1,607 ........................ 934,387 3,580,028 3,539,346 339914 ........ Costume jewelry and novelty manufacturing ........................... 590 590 6,775 590 590 1,088 ........................ 751,192 1,273,206 1,273,206 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56346 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–3—CHARACTERISTICS OF INDUSTRIES

AFFECTED BY OSHA’

S

PROPOSED

STANDARD FOR

SILICA—ALL

ENTITIES—Continued 

NAICS Industry Total entities a Total estab- lish-ments a Total employ- ment a Total affected entities b Total affected establish- ments b Total affected employment b Total FTE affected employees b Total revenues ($1,000) c Revenues per entity Revenues per establishment 

339950 ........ Sign manufacturing ................................................................... 6,291 6,415 89,360 487 496 496 ........................ 11,299,429 1,796,126 1,761,407 423840 ........ Industrial supplies, wholesalers ................................................ 7,016 10,742 111,198 250 383 383 ........................ 19,335,522 2,755,918 1,799,993 482110 ........ Rail transportation .................................................................... N/A N/A N/A N/A N/A 16,895 ........................ N/A N/A N/A 621210 ........ Dental offices ............................................................................ 119,471 124,553 817,396 7,655 7,980 7,980 ........................ 88,473,742 740,546 710,330 

Subtotals—General Industry and maritime ....................... 219,203 238,942 4,406,990 47,007 56,121 294,886 ........................ 1,101,555,989 5,025,278 4,610,140 Totals—All Industries ........................................................ 1,025,888 1,041,291 17,508,728 532,866 533,597 2,144,061 652,029 $2,649,803,698 $2,619,701 $2,544,729 

a U.S. Census Bureau, Statistics of U.S. Businesses, 2006. bOSHA estimates of employees potentially exposed to silica and associated entities and establishments. Affected entities and establishments constrained to be less than or equal to the number of affected employees. cEstimates based on 2002 receipts and payroll data from U.S. Census Bureau, Statistics of U.S. Businesses, 2002, and payroll data from the U.S. Census Bureau, Statistics of U.S. Businesses, 2006. Receipts are not reported for 2006, but were estimated assuming the ratio of receipts to payroll remained unchanged from 2002 to 2006. dState-plan states only. State and local governments are included under the construction sector because the silica risks for public employees are the result of construction-related activities. eOSHA estimates that only one-third of the entities and establishments in this industry, as reported above, use silica-containing inputs. 

Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on ERG, 2013. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56347 

9 It should be emphasized that these percentages 

vary significantly depending on the industry sector 

and, within an industry sector, depending on the 

NAICS industry. For example, about 14 percent of 

the workers in construction, but only 7 percent of 

workers in general industry, actually engage in 

activities involving silica exposure. As an example 

within construction, about 63 percent of workers in 

highway, street, and bridge construction, but only 

3 percent of workers in state and local governments, 

actually engage in activities involving silica 

exposure. 

10FTE affected workers becomes a relevant 

variable in the estimation of control costs in the 

construction industry. The reason is that, consistent 

with the costing methodology, control costs depend 

only on how many worker-days there are in which 

exposures are above the PEL. These are the workerdays in which controls are required. For the 

derivation of FTEs, see Tables IV–8 and IV–22 and 

the associated text in ERG (2007a). 

As shown in Table VIII–3, OSHA 

estimates that a total of 533,000 entities 

(486,000 in construction; 47,000 in 

general industry and maritime), 534,000 

establishments (477,500 in construction; 

56,100 in general industry and 

maritime), and 2.1 million workers (1.8 

million in construction; 0.3 million in 

general industry and maritime) would 

be affected by the proposed silica rule. 

Note that only slightly more than 50 

percent of the entities and 

establishments, and about 12 percent of 

the workers in affected industries, 

actually engage in activities involving 

silica exposure.9

The ninth column in Table VIII–3, 

with data only for construction, shows 

for each affected NAICS construction 

industry the number of full-timeequivalent (FTE) affected workers that 

corresponds to the total number of 

affected construction workers in the 

previous column.10 This distinction is 

necessary because affected construction 

workers may spend large amounts of 

time working on tasks with no risk of 

silica exposure. As shown in Table VIII– 

3, the 1.8 million affected workers in 

construction converts to approximately 

652,000 FTE affected workers. In 

contrast, OSHA based its analysis of the 

affected workers in general industry and 

maritime on the assumption that they 

were engaged full time in activities with 

some silica exposure. 

The last three columns in Table VIII– 

3 show combined total revenues for all 

entities (not just affected entities) in 

each affected industry, and the average 

revenue per entity and per 

establishment in each affected industry. 

Because OSHA did not have data to 

distinguish revenues for affected entities 

and establishments in any industry, 

average revenue per entity and average 

revenue per affected entity (as well as 

average revenue per establishment and 

average revenue per affected 

establishment) are estimated to be equal 

in value. 

Silica Exposure Profile of At-Risk 

Workers 

The technological feasibility analyses 

presented in Chapter IV of the PEA 

contain data and discussion of worker 

exposures to silica throughout industry. 

Exposure profiles, by job category, were 

developed from individual exposure 

measurements that were judged to be 

substantive and to contain sufficient 

accompanying description to allow 

interpretation of the circumstance of 

each measurement. The resulting 

exposure profiles show the job 

categories with current overexposures to 

silica and, thus, the workers for whom 

silica controls would be implemented 

under the proposed rule. 

Chapter IV of the PEA includes a 

section with a detailed description of 

the methods used to develop the 

exposure profile and to assess the 

technological feasibility of the proposed 

standard. That section documents how 

OSHA selected and used the data to 

establish the exposure profiles for each 

operation in the affected industry 

sectors, and discusses sources of 

uncertainly including the following: 

• Data Selection—OSHA discusses 

how exposure samples with sample 

durations of less than 480 minutes (an 

8-hour shift) are used in the analysis. 

• Use of IMIS data—OSHA discusses 

the limitations of data from its 

Integrated Management Information 

System. 

• Use of analogous information— 

OSHA discusses how information from 

one industry or operation is used to 

describe exposures in other industries 

or operations with similar 

characteristics. 

• Non-Detects—OSHA discusses how 

exposure data that is identified as ‘‘less 

than the LOD (limit of detection)’’ is 

used in the analysis. 

OSHA seeks comment on the 

assumptions and data selection criteria 

the Agency used to develop the 

exposure profiles shown in Chapter IV 

of the PEA. 

Table VIII–4 summarizes, from the 

exposure profiles, the total number of 

workers at risk from silica exposure at 

any level, and the distribution of 8-hour 

TWA respirable crystalline silica 

exposures by job category for general 

industry and maritime sectors and for 

construction activities. Exposures are 

grouped into the following ranges: less 

than 25 mg/m3; ≥ 25 mg/m3 and ≤ 50 mg/ 

m3; > 50 mg/m3 and ≤ 100 mg/m3; > 100 

mg/m3 and ≤ 250 mg/m3; and greater than 

250 mg/m3. These frequencies represent 

the percentages of production 

employees in each job category and 

sector currently exposed at levels within 

the indicated range. 

Table VIII–5 presents data by NAICS 

code—for each affected general, 

maritime, and construction industry— 

on the estimated number of workers 

currently at risk from silica exposure, as 

well as the estimated number of workers 

at risk of silica exposure at or above 25 

mg/m3, above 50 mg/m3, and above 100 

mg/m3. As shown, an estimated 

1,026,000 workers (851,000 in 

construction; 176,000 in general 

industry and maritime) currently have 

silica exposures at or above the 

proposed action level of 25 mg/m3; an 

estimated 770,000 workers (648,000 in 

construction; 122,000 in general 

industry and maritime) currently have 

silica exposures above the proposed PEL 

of 50 mg/m3; and an estimated 501,000 

workers (420,000 in construction; 

81,000 in general industry and 

maritime) currently have silica 

exposures above 100 mg/m3—an 

alternative PEL investigated by OSHA 

for economic analysis purposes. 

BILLING CODE 4510–26–P 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56348 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 


mstockstill on DSK4VPTVN1PROD with PROPOSALS2EP12SE13.006</GPH>

Table VIII-4 

Distribution of Silica Exposures by Sector and Job Category or Activity 

Sector 

Construction 

General Industry/Maritime 

Job Category/Activity 

Abrasive Blasters 

Drywall Finishers 

Heavy Equipment Operators 

Hole Drillers Using Hand-Held Drills 

Jackhammer and Impact Drillers 

Masonry Cutters Using Portable Saws 

Masonry Cutters Using Stationary Saws 

Millers Using Portable or Mobile Machines 

Rock and Concrete Drillers 

Rock-Crushing Machine Operators and Tenders 

Tuckpointers and Grinders 

Underground Construction Workers 

Asphalt Paving Products Front-end loader operator 

Maintenance worker 

Plant operator 

Asphalt Roofing Materials Material handler 

Captive Foundries 

Concrete Products 

Cut Stone 

Dental Equipment 

Dental Laboratories 

FlalGlass 

Iron Foundries 

Jewelry 

Mineral Processing 

Mineral Wool 

Nonferrous Sand Casling 

Foundries 

Production operator 

Abrasive blasting operator 

Cleaning/Finishing operator 

Coremaker 

Furnace operator 

Housekeeping worker 

Knockout operator 

Maintenance operator 

Material handler 

Molder 

Pouring operator 

Sand systems operator 

Shakeout operator 

Abrasive blasting operator 

Finishing operator 

Forming Line operator 

Material handler 

Mixer Operator 

Packaging operator 

Abrasive blasting ops 

Fabricator 

Machine operator 

Sawyer 

Splitter/chipper 

Production operator 

Dental technician 

Batch operator 

Material handler 

Abrasive blasting operator 

Cleaning/Finishing operator 

Coremaker 

Furnace operator 

Housekeeping worker 

Knockout operator 

Maintenance operator 

Material handler 

Molder 

Pouring operator 

Sand systems operator 

Shakeout operator 

Jewelry workers 

Production worker 

Batch operator 

Materia! handler 

Abrasive blasting operator 

Cleaning/Finishing operator 

Coremaker 

<25 

~g/m3 

18.6% 

86.7% 

79.2% 

14.3% 

18.3% 

24.2% 

21.4% 

54.3% 

35.9% 

0.0% 

10.0% 

59.3% 

50.0% 

100.0% 

100.0% 

0.0% 

0.0% 

6.6% 

15.5% 

25.5% 

37.5% 

14.3% 

10.8% 

16.7% 

28.1% 

26.3% 

25.0% 

172% 

14.4% 

13.3% 

45.9% 

83.3% 

41.9% 

46.2% 

33.3% 

14.3% 

16.7% 

11.8% 

17.4% 

17.2% 

33.3% 

83.9% 

50.0% 

0.0% 

6.6% 

15.5% 

25.50

/0 

37.5% 

14.3% 

10.8% 

16.7% 

28.1% 

26.3% 

25.0% 

17.2% 

14.4% 

37.5% 

0.0% 

50.0% 

0.0% 

6.6% 

15.5% 

25.5% 

Silica Exposure Range 

25-50 

~g/m3 

11.9% 

6.7% 

8.3% 

28.6% 

8.3% 

9.9% 

25.0% 

20.0% 

17.9% 

0.0% 

8.5% 

18.5% 

0.0% 

0.0% 

0.0% 

28.6% 

60.0% 

24.6% 

21.6% 

32.1% 

25.0% 

14.3% 

35.1% 

25.0% 

18.8% 

24.3% 

25.0% 

15.5% 

25.8% 

6.7% 

16.2% 

7.1% 

22.6% 

15.4% 

0.0% 

28.6% 

33.3% 

17.6% 

26.1% 

13.8% 

0.0% 

12.9% 

0.0% 

16,7% 

24.6% 

21.6% 

32.1% 

25.0% 

14.3% 

35.1% 

25.0% 

18.8% 

24.3% 

25.0% 

15.5% 

25.8% 

18.8% 

82.4% 

0<0% 

16.7% 

24.6% 

21.6% 

321% 

50-100 

~g/m3 

100-250 >250 ~g/m3 ~g/m3 

16.9% 20.3% 

6.7% 0.0% 

8.3% 4.2% 

35.7% 14.3% 

15.6% 24.8% 

12.1% 38.5% 

25.0% 3.6% 

200% 2.9% 

17.9% 17.9% 

0.0% 20.0% 

11.9% 18.4% 

11.1% 7.4% 

50.0% 0.0% 

0.0% 0.0% 

0.0% 0.0% 

42.9% 28.6% 

200% 20.0% 

27.9% 27.9% 

19.2% 21.1% 

29.2% 9.4% 

0.0% 12.5% 

429% 14.3% 

18.9% 24.3% 

25.0% 12.5% 

31.3% 21.9% 

28.9% 19.1% 

16.7% 29.2% 

25.9% 27.6% 

29.9% 17.5% 

20.0% 26.7% 

10.8% 16.2% 

7.1% 2.4% 

19.4% 9.7% 

0.0% 30.8% 

33.3% 16.7% 

14.3% 14.3% 

8.3% 25.0% 

23.5% 35.3% 

39.1% 17.4% 

20.7% 48.3% 

33.3% 33.3% 

3.2% 0.0% 

33.3% 0.0% 

33.3% 33.3% 

27.9% 27.9% 

19.2% 21.1% 

29.2% 9.4% 

0.0% 12.5% 

42.9% 14.3% 

18.9% 24.3% 

25.0% 12.5% 

31.3% 21.9% 

28.9% 19.1% 

16.7% 29.2% 

25.9% 27.6% 

29.9% 17.5% 

12.5% 18.8% 

11.8% 5.9% 

33.3% 0.0% 

33.3% 33.3% 

27.9% 27.9% 

19.2% 

29.2% 

21.1% 

9.4% 

32.2% 

0.0% 

0.0% 

7.1% 

33.0% 

15.4% 

25.0% 

2.9% 

10.3% 

80.0% 

51.2% 

3.7% 

0.0% 

0.0% 

0.0% 

0.0% 

0.0% 

13.1% 

22.5% 

3.8% 

25.0% 

14.3% 

10.8% 

20.8% 

0.0% 

1.3% 

4.2% 

13.8% 

12.4% 

33.3% 

10.8% 

0.0% 

6.5% 

7.7% 

16.7% 

28.6% 

16.7% 

11.8% 

0.0% 

0.0% 

0.0% 

0.0% 

16.7% 

16.7% 

13.1% 

22.5% 

3.8% 

25.0% 

14.3% 

10.8% 

20.8% 

0.0% 

1.3% 

4.2% 

13.8% 

12.4% 

12.5% 

0.0% 

16.7% 

16.7% 

13.1% 

22.5% 

3.8% 

Total 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

1000% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

1000% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

1000% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 
Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56349 

BILLING CODE 4510–26–C 

TABLE VIII–5—NUMBERS OF WORKERS EXPOSED TO SILICA (BY AFFECTED INDUSTRY AND EXPOSURE LEVEL (μg/m3)) 

NAICS Industry 

Number of 

establishments 

Number of 

employees 

Numbers exposed to Silica 

>=0 >=25 >=50 >=100 >=250 

Construction 

236100 .............. Residential Building Construction .......... 198,912 966,198 55,338 32,260 24,445 14,652 7,502 

236200 .............. Nonresidential Building Construction ..... 44,702 741,978 173,939 83,003 63,198 39,632 20,504 

237100 .............. Utility System Construction .................... 21,232 496,628 217,070 76,687 53,073 28,667 9,783 

237200 .............. Land Subdivision .................................... 12,469 77,406 6,511 1,745 1,172 560 186 


mstockstill on DSK4VPTVN1PROD with PROPOSALS2EP12SE13.007</GPH>

Table VIII-4 

Distribution of Silica Exposures by Sector and Job Category or Activity 

(Continued) 

Sector Job Category/Activity 

Furnace operator 

Housekeeping worker 

Knockout operator 

Maintenance operator 

Materia! handler 

Molder 

Pouring operator 

Sand systems operator 

Shakeout operator 

Non-Sand Casting Foundries Abrasive blasting operator 

Cleaning/Finishing operator 

Coremaker 

Furnace operator 

Housekeeping worker 

Knockout operator 

Maintenance operator 

Material handler 

Molder 

Pouring operator 

Sand systems operator 

Shakeout operator 

Other Ferrous Sand Casting Abrasive blasting operator 

Foundries 

Other Glass Products 

Paint and Coatings 

Porcelain Enameling 

Pottery 

Railroads 

Ready mix 

Refractories 

Refractory Repair 

Shipyards 

Structural Clay 

Cleaning/Finishing operator 

Coremaker 

Furnace operator 

Housekeeping worker 

Knockout operator 

Maintenance operator 

Material handler 

Molder 

Pouring operator 

Sand systems operator 

Shakeout operator 

Batch operator 

Material handler 

Material handler 

Mixer operator 

Enamel preparer 

Porcelain applicator 

Coatings operator 

Coatings preparer 

Finishing operator 

Forming line operator 

Material handler 

Ballast dumper 

Machine operator 

Batch operator 

Maintenance operator 

Materia! handler 

Quality control technician 

Truck driver 

Ceramic fiber furnace operator 

Finishing operator 

Forming operator 

Material handler 

Packaging operator 

Production operator 

Abrasive blasters 

Forming line operator/Coatings blender 

Forming line operator/Formers 

Forming line operator/Pug mill operator 

Grinding operator 

Material handler/Loader operator 

Materia! handler/post-production 

Material handler/production 

Source: Technological feasibillty analysis in Chapter IV of the PEA 

<25 

~glm3 

37.5% 

14.3% 

10.8% 

16.7% 

28.1% 

26.3% 

25.0% 

17.2% 

14.4% 

6.6% 

15.5% 

25.5% 

37.5% 

14.3% 

10.8% 

16.7% 

28.1% 

26.3% 

25.0% 

172% 

14.4% 

6.6% 

15.5% 

25.5% 

37.5% 

14.3% 

10.8% 

16.7% 

28.1% 

26.3% 

25.0% 

17.2% 

14.4% 

50.0% 

0.0% 

100.0% 

800% 

33.3% 

52.2% 

18.9% 

5.3% 

15.4% 

25.6% 

38.1% 

50.0% 

21.0% 

100.0% 

60.0% 

75.0% 

100.0% 

0.0% 

100.0% 

100.0% 

45.5% 

33.3% 

50.0% 

20.0% 

0.0% 

10.0% 

27.0% 

0.0% 

21.4% 

42.9% 

70.3% 

30.0% 

Silica Exposure Range 

25-50 

~g/m3 

25.0% 

14.3% 

35.1% 

25.0% 

18.8% 

24.3% 

25.0% 

15.5% 

25.8% 

24.6% 

21.6% 

32.1% 

25.0% 

14.3% 

35.1% 

25.0% 

18.8% 

24.3% 

25.0% 

15.5% 

25.8% 

24.6% 

21.6% 

32.1% 

25.0% 

14.3% 

35.1% 

250% 

18.8% 

24.3% 

25.0% 

15.5% 

25.8% 

0.0% 

16.7% 

0.0% 

0.0% 

33.3% 

13.0% 

10.8% 

5.3% 

34.6% 

40.0% 

19.0% 

26.9% 

380% 

0.0% 

20.0% 

0.0% 

0.0% 

0.0% 

0.0% 

0.0% 

27.3% 

22.2% 

41.7% 

40.0% 

28.6% 

10.0% 

16.2% 

14.3% 

7.1% 

0.0% 

16.2% 

20.0% 

50-100 

~g/m3 

100-250 >250 ~g/m3 ~g/m3 

0.0% 12.5% 

42.9% 14.3% 

18.9% 24.3% 

25.0% 12.5% 

31.3% 21.9% 

28.9% 19.1% 

16.7% 

25.9% 

29.9% 

27.9% 

19.2% 

29.2% 

0.0% 

42.9% 

18.9% 

25.0% 

31.3% 

28.9% 

16.7% 

25.9% 

29.9% 

27.9% 

29.2% 

27.6% 

17.5% 

27.9% 

21.1% 

9.4% 

12.5% 

14.3% 

24.3% 

12.5% 

21.9% 

19.1% 

29.2% 

27.6% 

17.5% 

27.9% 

19.2% 21.1% 

29.2% 9.4% 

0.0% 12.5% 

42.9% 14.3% 

18.9% 24.3% 

25.0% 12.5% 

31.3% 21.9% 

28.9% 19.1% 

16.7% 29.2% 

25.9% 27.6% 

29.9% 17.5% 

33.3% 0.0% 

33.3% 33.3% 

0.0% 0.0% 

0.0% 0.0% 

33.3% 0.0% 

21.7% 0.0% 

16.2% 32.4% 

31.6% 26.3% 

19.2% 30.8% 

14.4% 20.0% 

19.0% 9.5% 

7.7% 7.7% 

23.0% 11.0% 

0.0% 0.0% 

20.0% 0.0% 

25.0% 0.0% 

0.0% 0.0% 

0.0% 0.0% 

0.0% 0.0% 

0.0% 0.0% 

13.6% 13.6% 

22.2% 18.5% 

0.0% 8.3% 

20.0% 20.0% 

14.3% 14.3% 

50.0% 30.0% 

16.2% 29.7% 

14.3% 28.6% 

21.4% 28.6% 

28.6% 28.6% 

10.8% 2.7% 

30.0% 15.0% 

25.0% 

14.3% 

10.8% 

20.8% 

0.0% 

1.3% 

4.2% 

13.8% 

12.4% 

13.1% 

22.5% 

3.8% 

25.0% 

14.3% 

10.8% 

20.8% 

0.0% 

1.3% 

42% 

13.8% 

12.4% 

13.1% 

22.5% 

3.8% 

25.0% 

14.3% 

10.8% 

20.8% 

0.0% 

1.3% 

4.2% 

13.8% 

12.4% 

16.7% 

16.7% 

0.0% 

20.0% 

0.0% 

13.0% 

21.6% 

31.6% 

0.0% 

0.0% 

14.3% 

7.7% 

7.0% 

0.0% 

0.0% 

0.0% 

0.0% 

100.0% 

0.0% 

0.0% 

0.0% 

3.7% 

0.0% 

0.0% 

42.9% 

0.0% 

10.8% 

42.9% 

21.4% 

0.0% 

0.0% 

5.0% 

Total 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

1000% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 

100.0% 
56350 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–5—NUMBERS OF WORKERS EXPOSED TO SILICA (BY AFFECTED INDUSTRY AND EXPOSURE LEVEL (μg/m3))— 

Continued 

NAICS Industry 

Number of 

establishments 

Number of 

employees 

Numbers exposed to Silica 

>=0 >=25 >=50 >=100 >=250 

237300 .............. Highway, Street, and Bridge Construction.11,860 325,182 204,899 58,441 39,273 19,347 7,441 

237900 .............. Other Heavy and Civil Engineering Construction.5,561 90,167 46,813 12,904 8,655 4,221 1,369 

238100 .............. Foundation, Structure, and Building Exterior Contractors.117,456 1,167,986 559,729 396,582 323,119 237,537 134,355 

238200 .............. Building Equipment Contractors ............ 182,368 1,940,281 20,358 6,752 4,947 2,876 1,222 

238300 .............. Building Finishing Contractors ............... 133,343 975,335 120,012 49,202 37,952 24,662 14,762 

238900 .............. Other Specialty Trade Contractors ........ 74,446 557,638 274,439 87,267 60,894 32,871 13,718 

999000 .............. State and local governments [d] ............ NA 5,762,939 170,068 45,847 31,080 15,254 5,161 

Subtotals— 

Construction.

................................................................ 802,349 13,101,738 1,849,175 850,690 647,807 420,278 216,003 

General Industry and Maritime 

324121 .............. Asphalt paving mixture and block manufacturing.1,431 14,471 5,043 48 48 0 0 

324122 .............. Asphalt shingle and roofing materials .... 224 12,631 4,395 4,395 1,963 935 0 

325510 .............. Paint and coating manufacturing ........... 1,344 46,209 3,285 404 404 404 404 

327111 .............. Vitreous china plumbing fixtures & bathroom accessories manufacturing.41 5,854 2,802 2,128 1,319 853 227 

327112 .............. Vitreous china, fine earthenware, & 

other pottery product manufacturing.

731 9,178 4,394 3,336 2,068 1,337 356 

327113 .............. Porcelain electrical supply mfg .............. 125 6,168 2,953 2,242 1,390 898 239 

327121 .............. Brick and structural clay mfg ................. 204 13,509 5,132 3,476 2,663 1,538 461 

327122 .............. Ceramic wall and floor tile mfg .............. 193 7,094 2,695 1,826 1,398 808 242 

327123 .............. Other structural clay product mfg .......... 49 1,603 609 412 316 182 55 

327124 .............. Clay refractory manufacturing ................ 129 4,475 1,646 722 364 191 13 

327125 .............. Nonclay refractory manufacturing .......... 105 5,640 2,075 910 459 241 17 

327211 .............. Flat glass manufacturing ........................ 83 11,003 271 164 154 64 45 

327212 .............. Other pressed and blown glass and 

glassware manufacturing.

499 20,625 1,034 631 593 248 172 

327213 .............. Glass container manufacturing .............. 72 14,392 722 440 414 173 120 

327320 .............. Ready-mixed concrete manufacturing ... 6,064 107,190 43,920 32,713 32,110 29,526 29,526 

327331 .............. Concrete block and brick mfg ................ 951 22,738 10,962 5,489 3,866 2,329 929 

327332 .............. Concrete pipe mfg .................................. 385 14,077 6,787 3,398 2,394 1,442 575 

327390 .............. Other concrete product mfg ................... 2,281 66,095 31,865 15,957 11,239 6,769 2,700 

327991 .............. Cut stone and stone product manufacturing.1,943 30,633 12,085 10,298 7,441 4,577 1,240 

327992 .............. Ground or treated mineral and earth 

manufacturing.

271 6,629 5,051 5,051 891 297 0 

327993 .............. Mineral wool manufacturing ................... 321 19,241 1,090 675 632 268 182 

327999 .............. All other misc. nonmetallic mineral product mfg.465 10,028 4,835 2,421 1,705 1,027 410 

331111 .............. Iron and steel mills ................................. 805 108,592 614 456 309 167 57 

331112 .............. Electrometallurgical ferroalloy product 

manufacturing.

22 2,198 12 9 6 3 1 

331210 .............. Iron and steel pipe and tube manufacturing from purchased steel.240 21,543 122 90 61 33 11 

331221 .............. Rolled steel shape manufacturing ......... 170 10,857 61 46 31 17 6 

331222 .............. Steel wire drawing .................................. 288 14,669 83 62 42 23 8 

331314 .............. Secondary smelting and alloying of aluminum.150 7,381 42 31 21 11 4 

331423 .............. Secondary smelting, refining, and 

alloying of copper.

31 1,278 7 5 4 2 1 

331492 .............. Secondary smelting, refining, and 

alloying of nonferrous metal (except 

cu & al).

217 9,383 53 39 27 14 5 

331511 .............. Iron foundries ......................................... 527 59,209 22,111 16,417 11,140 6,005 2,071 

331512 .............. Steel investment foundries ..................... 132 16,429 5,934 4,570 3,100 1,671 573 

331513 .............. Steel foundries (except investment) ...... 222 17,722 6,618 4,914 3,334 1,797 620 

331524 .............. Aluminum foundries (except die-casting) 466 26,565 9,633 7,418 5,032 2,712 931 

331525 .............. Copper foundries (except die-casting) ... 256 6,120 2,219 1,709 1,159 625 214 

331528 .............. Other nonferrous foundries (except diecasting).124 4,710 1,708 1,315 892 481 165 

332111 .............. Iron and steel forging ............................. 398 26,596 150 112 76 41 14 

332112 .............. Nonferrous forging ................................. 77 8,814 50 37 25 13 5 

332115 .............. Crown and closure manufacturing ......... 59 3,243 18 14 9 5 2 

332116 .............. Metal stamping ....................................... 1,641 64,724 366 272 184 99 34 

332117 .............. Powder metallurgy part manufacturing .. 129 8,362 47 35 24 13 4 

332211 .............. Cutlery and flatware (except precious) 

manufacturing.

141 5,779 33 24 16 9 3 

332212 .............. Hand and edge tool manufacturing ....... 1,155 36,622 207 154 104 56 19 

332213 .............. Saw blade and handsaw manufacturing 136 7,304 41 31 21 11 4 

332214 .............. Kitchen utensil, pot, and pan manufacturing.70 3,928 22 17 11 6 2 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56351 

TABLE VIII–5—NUMBERS OF WORKERS EXPOSED TO SILICA (BY AFFECTED INDUSTRY AND EXPOSURE LEVEL (μg/m3))— 

Continued 

NAICS Industry 

Number of 

establishments 

Number of 

employees 

Numbers exposed to Silica 

>=0 >=25 >=50 >=100 >=250 

332323 .............. Ornamental and architectural metal 

work.

2,450 39,947 54 26 19 7 7 

332439 .............. Other metal container manufacturing .... 401 15,195 86 64 43 23 8 

332510 .............. Hardware manufacturing ........................ 828 45,282 256 190 129 69 24 

332611 .............. Spring (heavy gauge) manufacturing ..... 113 4,059 23 17 12 6 2 

332612 .............. Spring (light gauge) manufacturing ........ 340 15,336 87 64 44 24 8 

332618 .............. Other fabricated wire product manufacturing.1,198 36,364 205 153 104 56 19 

332710 .............. Machine shops ....................................... 21,356 266,597 1,506 1,118 759 409 141 

332812 .............. Metal coating and allied services ........... 2,599 56,978 4,695 2,255 1,632 606 606 

332911 .............. Industrial valve manufacturing ............... 488 38,330 216 161 109 59 20 

332912 .............. Fluid power valve and hose fitting manufacturing.381 35,519 201 149 101 55 19 

332913 .............. Plumbing fixture fitting and trim manufacturing.144 11,513 65 48 33 18 6 

332919 .............. Other metal valve and pipe fitting manufacturing.268 18,112 102 76 51 28 10 

332991 .............. Ball and roller bearing manufacturing .... 180 27,197 154 114 77 42 14 

332996 .............. Fabricated pipe and pipe fitting manufacturing.765 27,201 154 114 77 42 14 

332997 .............. Industrial pattern manufacturing ............ 461 5,281 30 22 15 8 3 

332998 .............. Enameled iron and metal sanitary ware 

manufacturing.

76 5,655 96 56 38 16 11 

332999 .............. All other miscellaneous fabricated metal 

product manufacturing.

3,123 72,201 408 303 205 111 38 

333319 .............. Other commercial and service industry 

machinery manufacturing.

1,349 53,012 299 222 151 81 28 

333411 .............. Air purification equipment manufacturing 351 14,883 84 62 42 23 8 

333412 .............. Industrial and commercial fan and blower manufacturing.163 10,506 59 44 30 16 6 

333414 .............. Heating equipment (except warm air 

furnaces) manufacturing.

407 20,577 116 86 59 32 11 

333511 .............. Industrial mold manufacturing ................ 2,126 39,917 226 168 114 61 21 

333512 .............. Machine tool (metal cutting types) manufacturing.530 17,220 97 72 49 26 9 

333513 .............. Machine tool (metal forming types) 

manufacturing.

285 8,556 48 36 24 13 5 

333514 .............. Special die and tool, die set, jig, and fixture manufacturing.3,232 57,576 325 241 164 88 30 

333515 .............. Cutting tool and machine tool accessory 

manufacturing.

1,552 34,922 197 146 99 54 18 

333516 .............. Rolling mill machinery and equipment 

manufacturing.

73 3,020 17 13 9 5 2 

333518 .............. Other metalworking machinery manufacturing.383 12,470 70 52 35 19 7 

333612 .............. Speed changer, industrial high-speed 

drive, and gear manufacturing.

226 12,374 70 52 35 19 7 

333613 .............. Mechanical power transmission equipment manufacturing.231 15,645 88 66 44 24 8 

333911 .............. Pump and pumping equipment manufacturing.490 30,764 174 129 88 47 16 

333912 .............. Air and gas compressor manufacturing 318 21,417 121 90 61 33 11 

333991 .............. Power-driven handtool manufacturing ... 150 8,714 49 37 25 13 5 

333992 .............. Welding and soldering equipment manufacturing.275 15,853 90 67 45 24 8 

333993 .............. Packaging machinery manufacturing ..... 619 21,179 120 89 60 32 11 

333994 .............. Industrial process furnace and oven 

manufacturing.

335 10,720 61 45 31 16 6 

333995 .............. Fluid power cylinder and actuator manufacturing.319 19,887 112 83 57 31 11 

333996 .............. Fluid power pump and motor manufacturing.178 13,631 77 57 39 21 7 

333997 .............. Scale and balance (except laboratory) 

manufacturing.

102 3,748 21 16 11 6 2 

333999 .............. All other miscellaneous general purpose 

machinery manufacturing.

1,725 52,454 296 220 149 80 28 

334518 .............. Watch, clock, and part manufacturing ... 106 2,188 12 9 6 3 1 

335211 .............. Electric housewares and household 

fans.

105 7,425 22 10 8 3 3 

335221 .............. Household cooking appliance manufacturing.125 16,033 47 22 16 6 6 

335222 .............. Household refrigerator and home freezer manufacturing.26 17,121 50 24 17 7 7 

335224 .............. Household laundry equipment manufacturing.23 16,269 47 23 17 6 6 

335228 .............. Other major household appliance manufacturing.45 12,806 37 18 13 5 5 

336111 .............. Automobile manufacturing ..................... 181 75,225 425 316 214 115 40 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56352 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–5—NUMBERS OF WORKERS EXPOSED TO SILICA (BY AFFECTED INDUSTRY AND EXPOSURE LEVEL (μg/m3))— 

Continued 

NAICS Industry 

Number of 

establishments 

Number of 

employees 

Numbers exposed to Silica 

>=0 >=25 >=50 >=100 >=250 

336112 .............. Light truck and utility vehicle manufacturing.94 103,815 587 436 296 159 55 

336120 .............. Heavy duty truck manufacturing ............ 95 32,122 181 135 91 49 17 

336211 .............. Motor vehicle body manufacturing ......... 820 47,566 269 200 135 73 25 

336212 .............. Truck trailer manufacturing .................... 394 32,260 182 135 92 50 17 

336213 .............. Motor home manufacturing .................... 91 21,533 122 90 61 33 11 

336311 .............. Carburetor, piston, piston ring, and 

valve manufacturing.

116 10,537 60 44 30 16 6 

336312 .............. Gasoline engine and engine parts manufacturing.876 66,112 373 277 188 101 35 

336322 .............. Other motor vehicle electrical and electronic equipment manufacturing.697 62,016 350 260 176 95 33 

336330 .............. Motor vehicle steering and suspension 

components (except spring) manufacturing.

257 39,390 223 165 112 60 21 

336340 .............. Motor vehicle brake system manufacturing.241 33,782 191 142 96 52 18 

336350 .............. Motor vehicle transmission and power 

train parts manufacturing.

535 83,756 473 351 238 128 44 

336370 .............. Motor vehicle metal stamping ................ 781 110,578 624 464 315 170 58 

336399 .............. All other motor vehicle parts manufacturing.1,458 149,251 843 626 425 229 79 

336611 .............. Ship building and repair ......................... 635 87,352 2,798 2,798 1,998 1,599 1,199 

336612 .............. Boat building .......................................... 1,129 54,705 1,752 1,752 1,252 1,001 751 

336992 .............. Military armored vehicle, tank, and tank 

component manufacturing.

57 6,899 39 29 20 11 4 

337215 .............. Showcase, partition, shelving, and locker manufacturing.1,733 59,080 334 248 168 91 31 

339114 .............. Dental equipment and supplies manufacturing.763 15,550 411 274 274 137 0 

339116 .............. Dental laboratories ................................. 7,261 47,088 33,214 5,357 1,071 0 0 

339911 .............. Jewelry (except costume) manufacturing.1,777 25,280 7,813 4,883 3,418 2,442 977 

339913 .............. Jewelers’ materials and lapidary work 

manufacturing.

264 5,199 1,607 1,004 703 502 201 

339914 .............. Costume jewelry and novelty manufacturing.590 6,775 1,088 685 479 338 135 

339950 .............. Sign manufacturing ................................ 6,415 89,360 496 249 172 57 57 

423840 .............. Industrial supplies, wholesalers ............. 10,742 111,198 383 306 153 77 0 

482110 .............. Rail transportation .................................. NA NA 16,895 11,248 5,629 2,852 1,233 

621210 .............. Dental offices ......................................... 124,553 817,396 7,980 1,287 257 0 0 

Subtotals— 

General 

Industry 

and Maritime.

................................................................ 238,942 4,406,990 294,886 175,801 122,472 80,731 48,956 

Totals ................................................................ 1,041,291 17,508,728 2,144,061 1,026,491 770,280 501,009 264,959 

Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on Table III–5 and the technological feasibility 

analysis presented in Chapter IV of the PEA. 

D. Technological Feasibility Analysis of 

the Proposed Permissible Exposure 

Limit to Crystalline Silica Exposures 

Chapter IV of the Preliminary 

Economic Analysis (PEA) provides the 

technological feasibility analysis that 

guided OSHA’s selection of the 

proposed PEL, consistent with the 

requirements of the Occupational Safety 

and Health Act (‘‘OSH Act’’), 29 U.S.C. 

651 et seq. Section 6(b)(5) of the OSH 

Act requires that OSHA ‘‘set the 

standard which most adequately 

assures, to the extent feasible, on the 

basis of the best available evidence, that 

no employee will suffer material 

impairment of health or functional 

capacity.’’ 29 U.S.C. 655(b)(5) (emphasis 

added). The Court of Appeals for the 

D.C. Circuit has clarified the Agency’s 

obligation to demonstrate the 

technological feasibility of reducing 

occupational exposure to a hazardous 

substance: 

OSHA must prove a reasonable possibility 

that the typical firm will be able to develop 

and install engineering and work practice 

controls that can meet the PEL in most of its 

operations . . . The effect of such proof is to 

establish a presumption that industry can 

meet the PEL without relying on respirators 

. . . Insufficient proof of technological 

feasibility for a few isolated operations 

within an industry, or even OSHA’s 

concession that respirators will be necessary 

in a few such operations, will not undermine 

this general presumption in favor of 

feasibility. Rather, in such operations firms 

will remain responsible for installing 

engineering and work practice controls to the 

extent feasible, and for using them to reduce 

. . . exposure as far as these controls can do 

so. 

United Steelworkers of America, AFL– 

CIO–CIC v. Marshall, 647 F.2d 1189, 

1272 (D.C. Cir. 1980). 

Additionally, the D.C. Circuit has 

explained that ‘‘[f]easibility of 

compliance turns on whether exposure 

levels at or below [the PEL] can be met 

in most operations most of the time. 

. . .’’ American Iron & Steel Inst. v. 

OSHA, 939 F.2d 975, 990 (D.C. Cir. 

1991). 

To demonstrate the limits of 

feasibility, OSHA’s analysis examines 

the technological feasibility of the 

proposed PEL of 50 mg/m3, as well as 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56353 

11Note that OSHA’s technological feasibility 

analysis contains 21 general industry sections. The 

number is expanded to 23 in this summary because 

Table VIII.D–1 describes the foundry industry as 

three different sectors (ferrous, nonferrous, and 

non-sand casting foundries) to provide a more 

detailed analysis of exposures. 

12Note that sensitivity refers to the smallest 

quantity that can be measured with a specified level 

of accuracy, expressed either as the limit of 

detection or limit of quantification. 

the technological feasibility of an 

alternative PEL of 25 mg/m3. In total, 

OSHA analyzed technological feasibility 

in 108 operations in general industry, 

maritime, and construction industries. 

This analysis addresses two different 

aspects of technological feasibility: (1) 

The extent to which engineering 

controls can reduce and maintain 

exposures; and (2) the capability of 

existing sampling and analytical 

methods to measure silica exposures. 

The discussion below summarizes the 

findings in Chapter IV of the PEA (see 

Docket No. OSHA–2010–0034). 

Methodology 

The technological feasibility analysis 

relies on information from a wide 

variety of sources. These sources 

include published literature, OSHA 

inspection reports, NIOSH reports and 

engineering control feasibility studies, 

and information from other federal 

agencies, state agencies, labor 

organizations, industry associations, 

and other groups. OSHA has limited the 

analysis to job categories that are 

associated with substantial direct silica 

exposure. The technological feasibility 

analyses group the general industry and 

maritime workplaces into 23 industry 

sectors.11 The Agency has divided each 

industry sector into specific job 

categories on the basis of common 

materials, work processes, equipment, 

and available exposure control methods. 

OSHA notes that these job categories are 

intended to represent job functions; 

actual job titles and responsibilities 

might differ depending on the facility. 

OSHA has organized the construction 

industry by grouping workers into 12 

general construction activities. The 

Agency organized construction workers 

into general activities that create silica 

exposures rather than organizing them 

by job titles because construction 

workers often perform multiple 

activities and job titles do not always 

coincide with the sources of exposure. 

In organizing construction worker 

activity this way, OSHA was able to 

create a more accurate exposure profile 

and apply control methods to workers 

who perform these activities in any 

segment of the construction industry. 

The exposure profiles include silica 

exposure data only for workers in the 

United States. Information on 

international exposure levels is 

occasionally referenced for perspective 

or in discussions of control options. It 

is important to note that the vast 

majority of crystalline silica 

encountered by workers in the United 

States is in the quartz form, and the 

terms crystalline silica and quartz are 

often used interchangeably. Unless 

specifically indicated otherwise, all 

silica exposure data, samples, and 

results discussed in the technological 

feasibility analysis refer to 

measurements of personal breathing 

zone (PBZ) respirable crystalline silica. 

In general and maritime industries, 

the exposure profiles in the 

technological feasibility analysis consist 

mainly of full-shift samples, collected 

over periods of 360 minutes or more. By 

using full-shift sampling results, OSHA 

minimizes the number of results that are 

less than the limit of detection (LOD) 

and eliminates the ambiguity associated 

with the LOD for low air volume 

samples. Thus, results that are reported 

in the original data source as below the 

LOD are included without contributing 

substantial uncertainty regarding their 

relationship to the proposed PEL. This 

is particularly important for general 

industry samples, which on average 

have lower silica levels than typical 

results for many tasks in the 

construction industry. 

In general and maritime industries, 

the exposure level for the period 

sampled is assumed to have continued 

over any unsampled portion of the 

worker’s shift. OSHA has preliminarily 

determined that this sample criterion is 

valid because workers in these 

industries are likely to work at the same 

general task or same repeating set of 

tasks over most of their shift; thus, 

unsampled periods generally are likely 

to be similar to the sampled periods. 

In the construction industry, much of 

the data analyzed for the defined 

activities consisted of full-shift samples 

collected over periods of 360 minutes or 

more. Construction workers are likely to 

spend a shift working at multiple 

discrete tasks, independent of 

occupational titles, and do not normally 

engage in those discrete tasks for the 

entire duration of a shift. Therefore, the 

Agency occasionally included partialshift samples (periods of less than 360 

minutes), but has limited the use of 

partial-shift samples with results below 

the LOD, giving preference to data 

covering a greater part of the workers’ 

shifts. 

OSHA believes that the partial-shift 

samples were collected for the entire 

duration of the task and that the 

exposure to silica ended when the task 

was completed. Therefore, OSHA 

assumes that the exposure to silica was 

zero for the remaining unsampled time. 

OSHA understands that this may not 

always be the case, and that there may 

be activities other than the sampled 

tasks that affect overall worker 

exposures, but the documentation 

regarding these factors is insufficient to 

use in calculating a time-weighted 

average. It is important to note, 

however, that the Agency has identified 

to the best of its ability the construction 

activities that create significant 

exposures to respirable crystalline 

silica. 

In cases where exposure information 

from a specific job category is not 

available, OSHA has based that portion 

of the exposure profile on surrogate data 

from one or more similar job categories 

in related industries. The surrogate data 

is selected based on strong similarities 

of raw materials, equipment, worker 

activities, and exposure duration 

between the job categories. When used, 

OSHA has clearly identified the 

surrogate data and the relationship 

between the industries or job categories. 

1. Feasibility Determination of Sampling 

and Analytical Methods 

As part of its technological feasibility 

analysis, OSHA examined the capability 

of currently available sampling methods 

and sensitivity 12 and precision of 

currently available analytical methods 

to measure respirable crystalline silica 

(please refer to the ‘‘Feasibility of 

Measuring Respirable Crystalline Silica 

Exposures at The Proposed PEL’’ section 

in Chapter IV of the PEA). The Agency 

understands that several commercially 

available personal sampling cyclones 

exist that can be operated at flow rates 

that conform to the ISO/CEN particle 

size selection criteria with an acceptable 

level of bias. Some of these sampling 

devices are the Dorr-Oliver, HiggensDowel, BGI GK 2.69, and the SKC G–3 

cyclones. Bias against the ISO/CEN 

criteria will fall within ±20 percent, and 

often is within ±10 percent. 

Additionally, the Agency 

preliminarily concludes that all of the 

mentioned cyclones are capable of 

allowing a sufficient quantity of quartz 

to be collected from atmospheric 

concentrations as low as 25 mg/m3 to 

exceed the limit of quantification for the 

OSHA ID–142 analytical method, 

provided that a sample duration is at 

least 4 hours. Furthermore, OSHA 

believes that these devices are also 

capable of collecting more than the 

minimum amount of cristobalite at the 

proposed PEL and action level 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56354 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

necessary for quantification with 

OSHA’s method ID–142 for a full shift. 

One of these cyclones (GK 2.69) can also 

collect an amount of cristobalite 

exceeding OSHA’s limit of 

quantification (LOQ) with a 4-hour 

sample at the proposed PEL and action 

level. 

Regarding analytical methods to 

measure silica, OSHA investigated the 

sensitivity and precision of available 

methods. The Agency preliminarily 

concludes that the X-Ray Diffraction 

(XRD) and Infrared Spectroscopy (IR) 

methods of analysis are both sufficiently 

sensitive to quantify levels of quartz and 

cristobalite that would be collected on 

air samples taken from concentrations at 

the proposed PEL and action level. 

Available information shows that poor 

inter-laboratory agreement and lack of 

specificity render colorimetric 

spectrophotometry (another analytical 

method) inferior to XRD or IR 

techniques. As such, OSHA is proposing 

not to permit employers to rely on 

exposure monitoring results based on 

analytical methods that use colorimetric 

methods. 

For the OSHA XRD Method ID–142 

(revised December 1996), precision is 

±23 percent at a working range of 50 to 

160 mg crystalline silica, and the SAE 

(sampling and analytical error) is ±19 

percent. The NIOSH and MSHA XRD 

and IR methods report a similar degree 

of precision. OSHA’s Salt Lake 

Technical Center (SLTC) evaluated the 

precision of ID–142 at lower filter 

loadings and has shown an acceptable 

level of precision is achieved at filter 

loadings of approximately 40 mg and 20 

mg corresponding to the amounts 

collected from full-shift sampling at the 

proposed PEL and action level, 

respectively. This analysis showed that 

at filter loadings corresponding to the 

proposed PEL, the precision and SAE 

for quartz are ±17 and ±14 percent, 

respectively. For cristobalite, the 

precision and SAE are ±19 and ±16 

percent, respectively. These results 

indicate that employers can have 

confidence in sampling results for the 

purpose of assessing compliance with 

the PEL and identifying when 

additional engineering and work 

practice controls and/or respiratory 

protection are needed. 

For example, given an SAE for quartz 

of 0.14 at a filter load of 40 mg, 

employers can be virtually certain that 

the PEL is not exceeded where 

exposures are less than 43 mg/m3, which 

represents the lower 95-percent 

confidence limit (i.e., 50 mg/m3 minus 

50*0.14). At 43 mg/m3, a full-shift 

sample that collects 816 L of air will 

result in a filter load of 35 mg of quartz, 

or more than twice the LOQ for Method 

ID–142. Thus, OSHA believes that the 

method is sufficiently sensitive and 

precise to allow employers to 

distinguish between operations that 

have sufficient dust control to comply 

with the PEL from those that do not. 

Finally, OSHA’s analysis of PAT data 

indicates that most laboratories achieve 

good agreement in results for samples 

having filter loads just above 40 mg 

quartz (49–70 mg). 

At the proposed action level, the 

study by SLTC found the precision and 

SAE of the method for quartz at 20 mg 

to be ±19 and ±16 percent, respectively. 

For cristobalite, the precision and SAE 

at 20 mg were also ±19 and ±16 percent, 

respectively. OSHA believes that these 

results show that Method ID–142 can 

achieve a sufficient degree of precision 

for the purpose of identifying those 

operations where routine exposure 

monitoring should be conducted. 

However, OSHA also believes that 

limitations in the characterization of the 

precision of the analytical method in 

this range of filter load preclude the 

Agency from proposing a PEL of 25 mg/ 

m3 at this time. First, the measurement 

error increases by about 4 to 5 percent 

for a full-shift sample taken at 25 mg/m3

compared to one taken at 50 mg/m3, and 

the error would be expected to increase 

further as filter loads approach the limit 

of detection. Second, for an employer to 

be virtually certain that an exposure to 

quartz did not exceed 25 mg/m3 as an 

exposure limit, the exposure would 

have to be below 21 mg/m3 given the 

SAE of ±16 percent calculated from the 

SLTC study. For a full-shift sample of 

0.816 L of air, only about 17 mg of quartz 

would be collected at 21 mg/m3, which 

is near the LOQ for Method ID–142 and 

at the maximum acceptable LOD that 

would be required by the proposed rule. 

Thus, given a sample result that is 

below a laboratory’s reported LOD, 

employers might not be able to rule out 

whether a PEL of 25 mg/m3 was 

exceeded. 

Finally, there are no available data 

that describe the total variability seen 

between laboratories at filter loadings in 

the range of 20 mg crystalline silica since 

the lowest filter loading used in PAT 

samples is about 50 mg. Given these 

considerations, OSHA believes that a 

PEL of 50 mg/m3 is more appropriate in 

that employers will have more 

confidence that sampling results are 

properly informing them where 

additional dust controls and respiratory 

protection is needed. 

Based on the evaluation of the 

nationally recognized sampling and 

analytical methods for measuring 

respirable crystalline silica presented in 

the section titled ‘‘Feasibility of 

Measuring Respirable Crystalline Silica 

Exposures at The Proposed PEL’’ in 

Chapter IV of the PEA, OSHA 

preliminarily concludes that it is 

technologically feasible to reliably 

measure exposures of workers at the 

proposed PEL of 50 mg/m3 and action 

level of 25 mg/m3. OSHA notes that the 

sampling and analytical error is larger at 

the proposed action level than that for 

the proposed PEL. In the ‘‘Issues’’ 

section of this preamble (see Provisions 

of the Standards—Exposure 

Assessment), OSHA solicits comments 

on whether measurements of exposures 

at the proposed action level and PEL are 

sufficiently precise to permit employers 

to adequately determine when 

additional exposure monitoring is 

necessary under the standard, when to 

provide workers with the required 

medical surveillance, and when to 

comply with all other requirements of 

the proposed standard. OSHA also 

solicits comments on the 

appropriateness of specific requirements 

in the proposed standard for 

laboratories that perform analyses of 

respirable crystalline silica samples to 

reduce the variability between 

laboratories. 

2. Feasibility Determination of Control 

Technologies 

The Agency has conducted a 

feasibility analysis for each of the 

identified 23 general industry sectors 

and 12 construction industry activities 

that are potentially affected by the 

proposed silica standard. Additionally, 

the Agency identified 108 operations 

within those sectors/activities and 

developed exposure profiles for each 

operation, except for two industries, 

engineered stone products and 

landscape contracting industries. For 

these two industries, data satisfying 

OSHA’s criteria for inclusion in the 

exposure profile were unavailable (refer 

to the Methodology section in Chapter 

4 of the PEA for criteria). However, the 

Agency obtained sufficient information 

in both of these industries to make 

feasibility determinations (see Chapter 

IV Sections C.7 and C.11 of the PEA). 

Each feasibility analysis contains a 

description of the applicable operations, 

the baseline conditions for each 

operation (including the respirable 

silica samples collected), additional 

controls necessary to reduce exposures, 

and final feasibility determinations for 

each operation. 

3. Feasibility Findings for the Proposed 

Permissible Exposure Limit of 50 mg/m3

Tables VIII–6 and VIII–7 summarize 

all the industry sectors and construction 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56355 

activities studied in the technological 

feasibility analysis and show how many 

operations within each can achieve 

levels of 50 mg/m3 through the 

implementation of engineering and 

work practice controls. The tables also 

summarize the overall feasibility finding 

for each industry sector or construction 

activity based on the number of feasible 

versus not feasible operations. For the 

general industry sector, OSHA has 

preliminarily concluded that the 

proposed PEL of 50 mg/m3 is 

technologically feasible for all affected 

industries. For the construction 

activities, OSHA has determined that 

the proposed PEL of 50 mg/m3 is feasible 

in 10 out of 12 of the affected activities. 

Thus, OSHA preliminarily concludes 

that engineering and work practices will 

be sufficient to reduce and maintain 

silica exposures to the proposed PEL of 

50 mg/m3 or below in most operations 

most of the time in the affected 

industries. For those few operations 

within an industry or activity where the 

proposed PEL is not technologically 

feasible even when workers use 

recommended engineering and work 

practice controls (seven out of 108 

operations, see Tables VIII–6 and VIII– 

7), employers can supplement controls 

with respirators to achieve exposure 

levels at or below the proposed PEL. 

4. Feasibility Findings for an Alternative 

Permissible Exposure Limit of 25 mg/m3

Based on the information presented in 

the technological feasibility analysis, 

OSHA believes that engineering and 

work practice controls identified to date 

will not be sufficient to consistently 

reduce exposures to PELs lower than 50 

mg/m3. The Agency believes that a 

proposed PEL of 25 mg/m3, for example, 

would not be feasible for many 

industries, and to use respiratory 

protection would have to be required in 

most operations and most of the time to 

achieve compliance. 

However, OSHA has data indicating 

that an alternative PEL of 25 mg/m3 has 

already been achieved in several 

industries (e.g. asphalt paving products, 

dental laboratories, mineral processing, 

and paint and coatings manufacturing in 

general industry, and drywall finishers 

and heavy equipment operators in 

construction). In these industries, 

airborne respirable silica concentrations 

are inherently low because either small 

amounts of silica containing materials 

are handled or these materials are not 

subjected to high energy processes that 

generate large amounts of respirable 

dust. 

For many of the other industries, 

OSHA believes that engineering and 

work practice controls will not be able 

to reduce and maintain exposures to an 

alternative PEL of 25 mg/m3 in most 

operations and most of the time. This is 

especially the case in industries that use 

silica containing material in substantial 

quantities and industries with high 

energy operations. For example, in 

general industry, the ferrous foundry 

industry would not be able to comply 

with an alternative PEL of 25 mg/m3

without widespread respirator use. In 

this industry, silica containing sand is 

transported, used, and recycled in 

significant quantities to create castings, 

and as a result, workers can be exposed 

to high levels of silica in all steps of the 

production line. Additionally, some 

high energy operations in foundries 

create airborne dust that causes high 

worker exposures to silica. One of these 

operations is the shakeout process, 

where operators monitor equipment that 

separates castings from mold materials 

by mechanically vibrating or tumbling 

the casting. The dust generated from 

this process causes elevated silica 

exposures for shakeout operators and 

often contributes to exposures for other 

workers in a foundry. For small, 

medium, and large castings, exposure 

information with engineering controls 

in place show that exposures below 50 

mg/m3 can be consistently achieved, but 

exposures above an alternative PEL of 

25 mg/m3 still occur. With engineering 

controls in place, exposure data for 

these operations range from 13 mg/m3 to 

53 mg/m3, with many of the reported 

exposures above 25 mg/m3. 

In the construction industry, OSHA 

estimates that an alternative PEL of 25 

mg/m3 would be infeasible in most 

operations because most of them are 

high energy operations that produce 

significant levels of dust, causing 

workers to have elevated exposures, and 

available engineering controls would 

not be able to maintain exposures at or 

below the alternative PEL most of the 

time. For example, jackhammering is a 

high energy operation that creates a 

large volume of silica containing dust, 

which disburses rapidly in highly 

disturbed air. OSHA estimates that the 

exposure levels of most workers 

operating jackhammers outdoors will be 

reduced to less that 100 mg/m3 as an 8- 

hour TWA, by using either wet methods 

or LEV paired with a suitable vacuum. 

OSHA believes that typically, the 

majority of jackhammering is performed 

for less than four hours of a worker’s 

shift, and in these circumstances the 

Agency estimates that most workers will 

experience levels below 50 mg/m3. 

Jackhammer operators who work 

indoors or with multiple jackhammers 

will achieve similar results granted that 

the same engineering controls are used 

and that fresh air circulation is provided 

to prevent accumulation of respirable 

dust in a worker’s vicinity. OSHA does 

not have any data indicating that these 

control strategies would reduce 

exposures of most workers to levels of 

25 mg/m3 or less. 

5. Overall Feasibility Determination 

Based on the information presented in 

the technological feasibility analysis, 

the Agency believes that 50 mg/m3 is the 

lowest feasible PEL. An alternative PEL 

of 25 mg/m3 would not be feasible 

because the engineering and work 

practice controls identified to date will 

not be sufficient to consistently reduce 

exposures to levels below 25 mg/m3 in 

most operations most of the time. OSHA 

believes that an alternative PEL of 25 

mg/m3 would not be feasible for many 

industries, and that the use of 

respiratory protection would be 

necessary in most operations most of the 

time to achieve compliance. 

Additionally, the current methods of 

sampling analysis create higher errors 

and lower precision in measurement as 

concentrations of silica lower than the 

proposed PEL are analyzed. However, 

the Agency preliminarily concludes that 

these sampling and analytical methods 

are adequate to permit employers to 

comply with all applicable requirements 

triggered by the proposed action level 

and PEL. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56356 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–6—SUMMARY OF TECHNOLOGICAL FEASIBILITY OF CONTROL TECHNOLOGIES IN GENERAL AND MARITIME

INDUSTRIES AFFECTED BY SILICA EXPOSURES

Industry sector 

Total number 

of affected 

operations 

Number of operations for which 

the proposed PEL 

is achievable with 

engineering controls and work 

practice controls 

Number of operations for which 

the proposed PEL 

is NOT achievable 

with engineering 

controls and work 

practice controls 

Overall feasibility finding for industry sector 

Asphalt Paving Products ......................................................... 3 3 0 Feasible. 

Asphalt Roofing Materials ........................................................ 2 2 0 Feasible. 

Concrete Products ................................................................... 6 5 1 Feasible. 

Cut Stone ................................................................................. 5 5 0 Feasible. 

Dental Equipment and Suppliers ............................................. 1 1 0 Feasible. 

Dental Laboratories ................................................................. 1 1 0 Feasible. 

Engineered Stone Products ..................................................... 1 1 0 Feasible. 

Foundries: Ferrous* ................................................................. 12 12 0 Feasible. 

Foundries: Nonferrous* ............................................................ 12 12 0 Feasible. 

Foundries: Non-Sand Casting* ................................................ 11 11 0 Feasible. 

Glass ........................................................................................ 2 2 0 Feasible. 

Jewelry ..................................................................................... 1 1 0 Feasible. 

Landscape Contracting ............................................................ 1 1 0 Feasible. 

Mineral Processing .................................................................. 1 1 0 Feasible. 

Paint and Coatings .................................................................. 2 2 0 Feasible. 

Porcelain Enameling ................................................................ 2 2 0 Feasible. 

Pottery ...................................................................................... 5 5 0 Feasible. 

Railroads .................................................................................. 5 5 0 Feasible. 

Ready-Mix Concrete ................................................................ 5 4 1 Feasible. 

Refractories .............................................................................. 5 5 0 Feasible. 

Refractory Repair ..................................................................... 1 1 0 Feasible. 

Shipyards (Maritime Industry) .................................................. 2 1 1 Feasible. 

Structural Clay ......................................................................... 3 3 0 Feasible. 

Totals ................................................................................ 89 96.6% 3.4% 

* Section 8 of the Technological Feasibility Analysis includes four subsectors of the foundry industry. Each subsector includes its own exposure 

profile and feasibility analysis in that section. This table lists three of those four subsectors individually based on the difference in casting processes used and subsequent potential for silica exposure. The table does not include captive foundries because the captive foundry operations 

are incorporated into the larger manufacturing process of the parent foundry. 

TABLE VIII–7—SUMMARY OF TECHNOLOGICAL FEASIBILITY OF CONTROL TECHNOLOGIES IN CONSTRUCTION ACTIVITIES

AFFECTED BY SILICA EXPOSURES

Construction activity 

Total number 

of affected 

operations 

Number of 

operations for 

which the proposed PEL is 

achievable with 

engineering controls and work 

practice controls 

Number of 

operations for 

which the proposed PEL is 

NOT achievable 

with engineering 

controls and work 

practice controls 

Overall feasibility finding for activity 

Abrasive Blasters ..................................................................... 2 0 2 Not Feasible. 

Drywall Finishers ...................................................................... 1 1 0 Feasible. 

Heavy Equipment Operators ................................................... 1 1 0 Feasible. 

Hole Drillers Using Hand-Held Drills ....................................... 1 1 0 Feasible. 

Jackhammer and Impact Drillers ............................................. 1 1 0 Feasible. 

Masonry Cutters Using Portable Saws .................................... 3 3 0 Feasible. 

Masonry Cutters Using Stationary Saws ................................. 1 1 0 Feasible. 

Millers Using Portable and Mobile Machines .......................... 3 3 0 Feasible. 

Rock and Concrete Drillers ...................................................... 1 1 0 Feasible. 

Rock-Crushing Machine Operators and Tenders .................... 1 1 0 Feasible. 

Tuckpointers and Grinders ...................................................... 3 1 2 Not Feasible. 

Underground Construction Workers ........................................ 1 1 0 Feasible. 

Totals ................................................................................ 19 78.9% 21.1% 

E. Costs of Compliance 

Chapter V of the PEA in support of 

the proposed silica rule provides a 

detailed assessment of the costs to 

establishments in all affected industry 

sectors of reducing worker exposures to 

silica to an eight-hour time-weighted 

average (TWA) permissible exposure 

limit (PEL) of 50 mg/m3 and of 

complying with the proposed standard’s 

ancillary requirements. The discussion 

below summarizes the findings in the 

PEA cost chapter. OSHA’s preliminary 

cost assessment is based on the 

Agency’s technological feasibility 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56357 

13There are numerous instances of job 

reassignments and job specialties arising in 

response to OSHA regulation. For example, asbestos 

removal and confined space work in construction 

have become activities performed by well-trained 

specialized employees, not general laborers (whose 

only responsibility is to identify the presence of 

asbestos or a confined space situation and then to 

notify the appropriate specialist). 

14OSHA expected that such a structural change 

in construction work assignments would not have 

a significant effect on the benefits of the proposed 

rule. As discussed in Chapter VII of the PEA, the 

benefits of the proposed rule are relatively 

insensitive to changes in average occupational 

tenure or how total silica exposure in an industry 

is distributed among individual workers. 15Evidence of such technological responses to 

regulation is widespread (see for example Ashford, 

Ayers, and Stone (1985), OTA (1995), and OSHA’s 

regulatory reviews of existing standards under § 610 

of the Regulatory Flexibility Act (‘‘610 lookback 

reviews’’)). 16A dramatic example from OSHA’s 610 

lookback review of its 1984 ethylene oxide (EtO) 

standard is the use of EtO as a sterilant. OSHA 

estimated the costs of add-on controls for EtO 

sterilization, but in response to the standard, 

improved EtO sterilizers with built-in controls were 

developed and widely disseminated at about half 

the cost of the equipment with add-on controls. 

(See OSHA, 2005.) Lower-cost EtO sterilizers with 

built-in controls did not exist, and their 

development had not been predicted by OSHA, at 

the time the final rule was published in 1984. 

analysis presented in Chapter IV of the 

PEA (2013); analyses of the costs of the 

proposed standard conducted by 

OSHA’s contractor, Eastern Research 

Group (ERG, 2007a, 2007b, and 2013); 

and the comments submitted to the 

docket as part of the SBREFA panel 

process. 

OSHA estimates that the proposed 

rule will cost $657.9 million per year in 

2009 dollars. Costs originally estimated 

for earlier years were adjusted to 2009 

dollars using the appropriate price 

indices. All costs are annualized using 

a discount rate of 7 percent. (A 

sensitivity analysis using discount rates 

of 3 percent and 0 percent is presented 

in the discussion of net benefits.) Onetime costs are annualized over 10-year 

annualization period, and capital goods 

are annualized over the life of the 

equipment. OSHA has historically 

annualized one-time costs over at least 

a 10-year period, which approximately 

reflects the average life of a business in 

the United States. (The Agency has 

chosen a longer annualization period 

under special circumstances, such as 

when a rule involves longer and more 

complex phase-in periods. In general, a 

longer annualization period, in such 

cases, will tend to reduce annualized 

costs slightly.) 

The estimated costs for the proposed 

silica standard rule include the 

additional costs necessary for employers 

to achieve full compliance. They do not 

include costs associated with current 

compliance that has already been 

achieved with regard to the new 

requirements or costs necessary to 

achieve compliance with existing silica 

requirements, to the extent that some 

employers may currently not be fully 

complying with applicable regulatory 

requirements. 

Table VIII–8 provides the annualized 

costs of the proposed rule by cost 

category for general industry, maritime, 

and construction. As shown in Table 

VIII–8, of the total annualized costs of 

the proposed rule, $132.5 million would 

be incurred by general industry, $14.2 

million by maritime, and $511.2 million 

by construction. 

Table VIII–9 shows the annualized 

costs of the proposed rule by cost 

category and by industry for general 

industry and maritime, and Table VIII– 

10 shows the annualized costs similarly 

disaggregated for construction. These 

tables show that engineering control 

costs represent 69 percent of the costs 

of the proposed standard for general 

industry and maritime and 47 percent of 

the costs of the proposed standard for 

construction. Considering other leading 

cost categories, costs for exposure 

assessment and respirators represent, 

respectively, 20 percent and 5 percent of 

the costs of the proposed standard for 

general industry and maritime; costs for 

respirators and medical surveillance 

represent, respectively, 16 percent and 

15 percent of the costs of the proposed 

standard for construction. 

While the costs presented here 

represent the Agency’s best estimate of 

the costs to industry of complying with 

the proposed rule under static 

conditions (that is, using existing 

technology and the current deployment 

of workers), OSHA recognizes that the 

actual costs could be somewhat higher 

or lower, depending on the Agency’s 

possible overestimation or 

underestimation of various cost factors. 

In Chapter VII of the PEA, OSHA 

provides a sensitivity analysis of its cost 

estimates by modifying certain critical 

unit cost factors. Beyond the sensitivity 

analysis, however, OSHA believes its 

cost estimates may significantly 

overstate the actual costs of the 

proposed rule because, in response to 

the rule, industry may be able to take 

two types of actions to reduce 

compliance costs. 

First, in construction, 53 percent of 

the estimated costs of the proposed rule 

(all costs except engineering controls) 

vary directly with the number of 

workers exposed to silica. However, as 

shown in Table VIII–3 of this preamble, 

almost three times as many construction 

workers would be affected by the 

proposed rule as would the number of 

full-time-equivalent construction 

workers necessary to do the work. This 

is because most construction workers 

currently do work involving silica 

exposure for only a portion of their 

workday. In response to the proposed 

rule, many employers are likely to 

assign work so that fewer construction 

workers perform tasks involving silica 

exposure; correspondingly, construction 

work involving silica exposure will tend 

to become a full-time job for some 

construction workers.13 Were this 

approach fully implemented in 

construction, the actual cost of the 

proposed rule would decline by over 25 

percent, or by $180 million annually, to 

under $480 million annually.14

Second, the costs presented here do 

not take into account the likely 

development and dissemination of costreducing compliance technology in 

response to the proposed rule.15 One 

possible example is the development of 

safe substitutes for silica sand in 

abrasive blasting operations, repair and 

replacement of refractory materials, 

foundry operations, and the railroad 

transportation industry. Another is 

expanded uses of automated processes, 

which would allow workers to be 

isolated from the points of operation 

that involve silica exposure (such as 

tasks between the furnace and the 

pouring machine in foundries and at 

sand transfer stations in structural clay 

production facilities). Yet another 

example is the further development and 

use of bags with valves that seal 

effectively when filled, thereby 

preventing product leakage and worker 

exposure (for example, in mineral 

processing and concrete products 

industries). Probably the most pervasive 

and significant technological advances, 

however, will likely come from the 

integration of compliant control 

technology into production equipment 

as standard equipment. Such advances 

would both increase the effectiveness 

and reduce the costs of silica controls 

retrofitted to production equipment. 

Possible examples include local exhaust 

ventilation (LEV) systems attached to 

portable tools used by grinders and 

tuckpointers; enclosed operator cabs 

equipped with air filtration and air 

conditioning in industries that 

mechanically transfer silica or silicacontaining materials; and machineintegrated wet dust suppression systems 

used, for example, in road milling 

operations. Of course, all the possible 

technological advances in response to 

the proposed rule and their effects on 

costs are difficult to predict.16

OSHA has decided at this time not to 

create a more dynamic and predictive 

analysis of possible cost-reducing 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56358 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

technological advances or worker 

specialization because the technological 

and economic feasibility of the 

proposed rule can easily be 

demonstrated using existing technology 

and employment patterns. However, 

OSHA believes that actual costs, if 

future developments of this type were 

fully accounted for, would be lower 

than those estimated here. 

OSHA invites comment on this 

discussion concerning the costs of the 

proposed rule. 

TABLE VIII–8—ANNUALIZED COMPLIANCE COSTS FOR EMPLOYERS IN GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION

AFFECTED BY OSHA’S PROPOSED SILICA STANDARD

[2009 dollars] 

Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

assessment 

Medical 

surveillance Training 

Regulated 

areas or 

access control 

Total 

General Industry .......... $88,442,480 $6,914,225 $29,197,633 $2,410,253 $2,952,035 $2,580,728 $132,497,353 

Maritime ....................... 12,797,027 NA 671,175 646,824 43,865 70,352 14,229,242 

Construction ................. 242,579,193 84,004,516 44,552,948 76,012,451 47,270,844 16,745,663 511,165,616 

Total ...................... 343,818,700 90,918,741 74,421,757 79,069,527 50,266,744 19,396,743 657,892,211 

U.S. Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on ERG (2007a, 

2007b, and 2013). 

TABLE VIII–9—ANNUALIZED COMPLIANCE COSTS FOR ALL GENERAL INDUSTRY AND MARITIME ESTABLISHMENTS

AFFECTED BY THE PROPOSED SILICA STANDARD

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

assessment 

Medical 

surveillance Training Regulated areas Total 

324121 ..... Asphalt paving mixture and block manufacturing.$179,111 $2,784 $8,195 $962 $49,979 $1,038 $242,070 

324122 ..... Asphalt shingle and roofing materials .. 2,194,150 113,924 723,761 39,364 43,563 42,495 3,157,257 

325510 ..... Paint and coating manufacturing .......... 0 23,445 70,423 8,179 33,482 8,752 144,281 

327111 ..... Vitreous china plumbing fixtures & 

bathroom accessories manufacturing.

1,128,859 76,502 369,478 26,795 29,006 28,554 1,659,194 

327112 ..... Vitreous china, fine earthenware, & 

other pottery product manufacturing.

1,769,953 119,948 579,309 42,012 45,479 44,770 2,601,471 

327113 ..... Porcelain electrical supply mfg ............. 1,189,482 80,610 389,320 28,234 30,564 30,087 1,748,297 

327121 ..... Brick and structural clay mfg ................ 6,966,654 154,040 554,322 53,831 51,566 57,636 7,838,050 

327122 ..... Ceramic wall and floor tile mfg ............. 3,658,389 80,982 306,500 28,371 27,599 30,266 4,132,107 

327123 ..... Other structural clay product mfg ......... 826,511 18,320 72,312 6,417 6,302 6,838 936,699 

327124 ..... Clay refractory manufacturing .............. 304,625 21,108 124,390 7,393 17,043 7,878 482,438 

327125 ..... Nonclay refractory manufacturing ........ 383,919 26,602 156,769 9,318 21,479 9,929 608,017 

327211 ..... Flat glass manufacturing ...................... 227,805 8,960 29,108 3,138 2,800 3,344 275,155 

327212 ..... Other pressed and blown glass and 

glassware manufacturing.

902,802 34,398 111,912 12,048 10,708 12,839 1,084,706 

327213 ..... Glass container manufacturing ............. 629,986 24,003 78,093 8,374 7,472 8,959 756,888 

327320 ..... Ready-mixed concrete manufacturing .. 7,029,710 1,862,221 5,817,205 652,249 454,630 695,065 16,511,080 

327331 ..... Concrete block and brick mfg .............. 2,979,495 224,227 958,517 78,536 113,473 83,692 4,437,939 

327332 ..... Concrete pipe mfg ................................ 1,844,576 138,817 593,408 48,621 70,250 51,813 2,747,484 

327390 ..... Other concrete product mfg ................. 8,660,830 651,785 2,786,227 228,290 329,844 243,276 12,900,251 

327991 ..... Cut stone and stone product manufacturing.5,894,506 431,758 1,835,498 151,392 126,064 161,080 8,600,298 

327992 ..... Ground or treated mineral and earth 

manufacturing.

3,585,439 51,718 867,728 18,134 52,692 19,295 4,595,006 

327993 ..... Mineral wool manufacturing ................. 897,980 36,654 122,015 12,852 11,376 13,675 1,094,552 

327999 ..... All other misc. nonmetallic mineral 

product mfg.

1,314,066 98,936 431,012 34,691 50,435 36,911 1,966,052 

331111 ..... Iron and steel mills ............................... 315,559 17,939 72,403 6,129 5,836 6,691 424,557 

331112 ..... Electrometallurgical ferroalloy product 

manufacturing.

6,375 362 1,463 124 118 135 8,577 

331210 ..... Iron and steel pipe and tube manufacturing from purchased steel.62,639 3,552 14,556 1,239 1,222 1,328 84,537 

331221 ..... Rolled steel shape manufacturing ........ 31,618 1,793 7,348 625 617 670 42,672 

331222 ..... Steel wire drawing ................................ 42,648 2,419 9,911 843 832 904 57,557 

331314 ..... Secondary smelting and alloying of 

aluminum.

21,359 1,213 4,908 419 406 453 28,757 

331423 ..... Secondary smelting, refining, and 

alloying of copper.

3,655 207 857 72 71 78 4,940 

331492 ..... Secondary smelting, refining, and 

alloying of nonferrous metal (except 

cu & al).

27,338 1,551 6,407 539 531 580 36,946 

331511 ..... Iron foundries ........................................ 11,372,127 645,546 2,612,775 223,005 216,228 241,133 15,310,815 

331512 ..... Steel investment foundries ................... 3,175,862 179,639 739,312 62,324 58,892 67,110 4,283,138 

331513 ..... Steel foundries (except investment) ..... 3,403,790 193,194 794,973 67,027 65,679 72,174 4,596,837 

331524 ..... Aluminum foundries (except die-casting).5,155,172 291,571 1,220,879 101,588 97,006 108,935 6,975,150 

331525 ..... Copper foundries (except die-casting) 1,187,578 67,272 309,403 23,668 23,448 25,095 1,636,463 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56359 

TABLE VIII–9—ANNUALIZED COMPLIANCE COSTS FOR ALL GENERAL INDUSTRY AND MARITIME ESTABLISHMENTS

AFFECTED BY THE PROPOSED SILICA STANDARD—Continued 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

assessment 

Medical 

surveillance Training Regulated areas Total 

331528 ..... Other nonferrous foundries (except 

die-casting).

914,028 51,701 212,778 17,937 16,949 19,314 1,232,708 

332111 ..... Iron and steel forging ........................... 77,324 4,393 19,505 1,538 1,555 1,640 105,955 

332112 ..... Nonferrous forging ................................ 25,529 1,451 6,440 508 513 541 34,982 

332115 ..... Crown and closure manufacturing ....... 9,381 532 2,236 186 186 199 12,720 

332116 ..... Metal stamping ..................................... 188,102 10,676 45,595 3,734 3,736 3,988 255,832 

332117 ..... Powder metallurgy part manufacturing 24,250 1,375 5,727 481 479 514 32,828 

332211 ..... Cutlery and flatware (except precious) 

manufacturing.

16,763 952 4,229 333 337 355 22,970 

332212 ..... Hand and edge tool manufacturing ...... 106,344 6,041 26,356 2,110 2,118 2,255 145,223 

332213 ..... Saw blade and handsaw manufacturing.21,272 1,209 5,090 418 411 451 28,851 

332214 ..... Kitchen utensil, pot, and pan manufacturing.11,442 650 2,886 228 230 243 15,678 

332323 ..... Ornamental and architectural metal 

work.

28,010 1,089 4,808 383 572 406 35,267 

332439 ..... Other metal container manufacturing ... 44,028 2,502 11,106 876 885 934 60,330 

332510 ..... Hardware manufacturing ...................... 131,574 7,476 33,190 2,617 2,646 2,790 180,292 

332611 ..... Spring (heavy gauge) manufacturing ... 11,792 670 2,974 235 237 250 16,158 

332612 ..... Spring (light gauge) manufacturing ...... 44,511 2,529 11,228 885 895 944 60,992 

332618 ..... Other fabricated wire product manufacturing.105,686 6,005 26,659 2,102 2,125 2,241 144,819 

332710 ..... Machine shops ..................................... 774,529 44,074 211,043 15,533 16,157 16,423 1,077,759 

332812 ..... Metal coating and allied services ......... 2,431,996 94,689 395,206 33,145 48,563 35,337 3,038,935 

332911 ..... Industrial valve manufacturing .............. 111,334 6,316 25,894 2,197 2,159 2,361 150,261 

332912 ..... Fluid power valve and hose fitting 

manufacturing.

103,246 5,863 24,854 2,040 2,021 2,189 140,213 

332913 ..... Plumbing fixture fitting and trim manufacturing.33,484 1,901 8,060 661 655 710 45,472 

332919 ..... Other metal valve and pipe fitting manufacturing.52,542 2,984 12,648 1,038 1,028 1,114 71,354 

332991 ..... Ball and roller bearing manufacturing .. 79,038 4,488 19,027 1,561 1,547 1,676 107,338 

332996 ..... Fabricated pipe and pipe fitting manufacturing.78,951 4,483 19,006 1,560 1,545 1,674 107,219 

332997 ..... Industrial pattern manufacturing ........... 15,383 874 3,703 304 301 326 20,891 

332998 ..... Enameled iron and metal sanitary ware 

manufacturing.

46,581 2,225 9,304 774 969 831 60,684 

332999 ..... All other miscellaneous fabricated 

metal product manufacturing.

209,692 11,915 53,603 4,181 4,256 4,446 288,093 

333319 ..... Other commercial and service industry 

machinery manufacturing.

154,006 8,741 37,161 3,053 3,046 3,266 209,273 

333411 ..... Air purification equipment manufacturing.43,190 2,453 10,037 847 823 916 58,265 

333412 ..... Industrial and commercial fan and 

blower manufacturing.

30,549 1,735 7,099 599 582 648 41,212 

333414 ..... Heating equipment (except warm air 

furnaces) manufacturing.

59,860 3,399 13,911 1,174 1,141 1,269 80,754 

333511 ..... Industrial mold manufacturing .............. 116,034 6,597 30,348 2,317 2,375 2,460 160,131 

333512 ..... Machine tool (metal cutting types) 

manufacturing.

49,965 2,839 12,313 988 985 1,059 68,151 

333513 ..... Machine tool (metal forming types) 

manufacturing.

24,850 1,411 6,157 495 500 527 33,940 

333514 ..... Special die and tool, die set, jig, and 

fixture manufacturing.

167,204 9,513 44,922 3,346 3,458 3,545 231,988 

333515 ..... Cutting tool and machine tool accessory manufacturing.101,385 5,764 26,517 2,025 2,075 2,150 139,916 

333516 ..... Rolling mill machinery and equipment 

manufacturing.

8,897 506 2,327 178 182 189 12,279 

333518 ..... Other metalworking machinery manufacturing.36,232 2,060 9,476 724 742 768 50,002 

333612 ..... Speed changer, industrial high-speed 

drive, and gear manufacturing.

35,962 2,043 8,308 702 674 763 48,452 

333613 ..... Mechanical power transmission equipment manufacturing.45,422 2,581 10,493 886 852 963 61,197 

333911 ..... Pump and pumping equipment manufacturing.89,460 5,077 21,139 1,767 1,746 1,897 121,086 

333912 ..... Air and gas compressor manufacturing 62,241 3,534 14,975 1,230 1,219 1,320 84,518 

333991 ..... Power-driven handtool manufacturing .. 25,377 1,441 6,105 501 497 538 34,459 

333992 ..... Welding and soldering equipment manufacturing.46,136 2,622 10,882 904 879 978 62,401 

333993 ..... Packaging machinery manufacturing ... 61,479 3,491 15,004 1,219 1,218 1,304 83,714 

333994 ..... Industrial process furnace and oven 

manufacturing.

31,154 1,768 7,694 620 626 661 42,523 

333995 ..... Fluid power cylinder and actuator manufacturing.57,771 3,280 13,532 1,137 1,113 1,225 78,057 

333996 ..... Fluid power pump and motor manufacturing.39,598 2,247 9,296 782 772 840 53,535 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56360 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–9—ANNUALIZED COMPLIANCE COSTS FOR ALL GENERAL INDUSTRY AND MARITIME ESTABLISHMENTS

AFFECTED BY THE PROPOSED SILICA STANDARD—Continued 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

assessment 

Medical 

surveillance Training Regulated areas Total 

333997 ..... Scale and balance (except laboratory) 

manufacturing.

10,853 616 2,688 216 218 230 14,822 

333999 ..... All other miscellaneous general purpose machinery manufacturing.152,444 8,657 36,677 3,012 2,985 3,232 207,006 

334518 ..... Watch, clock, and part manufacturing .. 6,389 363 1,596 127 129 135 8,740 

335211 ..... Electric housewares and household 

fans.

11,336 437 1,641 149 203 163 13,928 

335221 ..... Household cooking appliance manufacturing.24,478 944 3,543 321 438 352 30,077 

335222 ..... Household refrigerator and home 

freezer manufacturing.

26,139 1,009 3,784 343 468 376 32,118 

335224 ..... Household laundry equipment manufacturing.24,839 958 3,596 326 444 357 30,521 

335228 ..... Other major household appliance manufacturing.19,551 754 2,830 256 350 281 24,023 

336111 ..... Automobile manufacturing .................... 218,635 12,444 49,525 4,203 3,914 4,636 293,357 

336112 ..... Light truck and utility vehicle manufacturing.301,676 17,170 68,335 5,799 5,400 6,397 404,778 

336120 ..... Heavy duty truck manufacturing ........... 93,229 5,303 21,179 1,800 1,692 1,977 125,181 

336211 ..... Motor vehicle body manufacturing ....... 138,218 7,849 32,738 2,722 2,674 2,931 187,131 

336212 ..... Truck trailer manufacturing ................... 93,781 5,325 21,786 1,841 1,791 1,989 126,512 

336213 ..... Motor home manufacturing .................. 62,548 3,557 14,284 1,212 1,147 1,326 84,073 

336311 ..... Carburetor, piston, piston ring, and 

valve manufacturing.

30,612 1,739 7,044 598 576 649 41,219 

336312 ..... Gasoline engine and engine parts 

manufacturing.

192,076 10,910 44,198 3,753 3,616 4,073 258,625 

336322 ..... Other motor vehicle electrical and electronic equipment manufacturing.180,164 10,233 41,457 3,520 3,392 3,820 242,586 

336330 ..... Motor vehicle steering and suspension 

components (except spring) manufacturing.

114,457 6,504 26,216 2,228 2,128 2,427 153,960 

336340 ..... Motor vehicle brake system manufacturing.98,118 5,573 22,578 1,917 1,847 2,080 132,114 

336350 ..... Motor vehicle transmission and power 

train parts manufacturing.

243,348 13,832 55,796 4,730 4,510 5,160 327,377 

336370 ..... Motor vehicle metal stamping .............. 321,190 18,237 73,408 6,282 6,057 6,810 431,985 

336399 ..... All other motor vehicle parts manufacturing.433,579 24,628 99,769 8,472 8,162 9,194 583,803 

336611 ..... Ship building and repair ....................... 7,868,944 NA 412,708 397,735 26,973 43,259 8,749,619 

336612 ..... Boat building ......................................... 4,928,083 NA 258,467 249,089 16,892 27,092 5,479,624 

336992 ..... Military armored vehicle, tank, and 

tank component manufacturing.

20,097 1,142 4,786 394 383 426 27,227 

337215 ..... Showcase, partition, shelving, and 

locker manufacturing.

171,563 9,741 41,962 3,405 3,412 3,638 233,720 

339114 ..... Dental equipment and supplies manufacturing.272,308 15,901 48,135 5,524 4,157 5,930 351,955 

339116 ..... Dental laboratories ............................... 103,876 62,183 892,167 21,602 335,984 23,193 1,439,004 

339911 ..... Jewelry (except costume) manufacturing.260,378 198,421 876,676 69,472 81,414 73,992 1,560,353 

339913 ..... Jewelers’ materials and lapidary work 

manufacturing.

53,545 40,804 180,284 14,287 16,742 15,216 320,878 

339914 ..... Costume jewelry and novelty manufacturing.54,734 27,779 122,885 9,726 11,337 10,359 236,821 

339950 ..... Sign manufacturing ............................... 227,905 9,972 44,660 3,491 5,173 3,718 294,919 

423840 ..... Industrial supplies, wholesalers ............ 97,304 8,910 60,422 3,149 4,199 3,315 177,299 

482110 ..... Rail transportation ................................ 0 327,176 1,738,398 110,229 154,412 121,858 2,452,073 

621210 ..... Dental offices ........................................ 24,957 14,985 251,046 5,286 87,408 5,572 389,256 

Total ...................................................... 101,239,507 6,914,225 29,868,808 3,057,076 2,995,900 2,651,079 146,726,595 

Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on ERG (2013). 

TABLE VIII–10—ANNUALIZED COMPLIANCE COSTS FOR CONSTRUCTION EMPLOYERS AFFECTED BY OSHA’S PROPOSED

SILICA STANDARD

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

assessment 

Medical 

surveillance Training 

Regulated 

areas and 

access control 

Total 

236100 ..... Residential Building Construction ......... $14,610,121 $2,356,507 $1,949,685 $2,031,866 $1,515,047 $825,654 $23,288,881 

236200 ..... Nonresidential Building Construction ... 16,597,147 7,339,394 4,153,899 6,202,842 4,349,517 1,022,115 39,664,913 

237100 ..... Utility System Construction .................. 30,877,799 2,808,570 4,458,900 2,386,139 5,245,721 941,034 46,718,162 

237200 ..... Land Subdivision .................................. 676,046 59,606 128,183 51,327 173,183 22,443 1,110,789 

237300 ..... Highway, Street, and Bridge Construction.16,771,688 2,654,815 3,538,146 2,245,164 4,960,966 637,082 30,807,861 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56361 

TABLE VIII–10—ANNUALIZED COMPLIANCE COSTS FOR CONSTRUCTION EMPLOYERS AFFECTED BY OSHA’S PROPOSED

SILICA STANDARD—Continued 

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

assessment 

Medical 

surveillance Training 

Regulated 

areas and 

access control 

Total 

237900 ..... Other Heavy and Civil Engineering 

Construction.

4,247,372 430,127 825,247 367,517 1,162,105 131,843 7,164,210 

238100 ..... Foundation, Structure, and Building 

Exterior Contractors.

66,484,670 59,427,878 17,345,127 50,179,152 14,435,854 8,034,530 215,907,211 

238200 ..... Building Equipment Contractors ........... 3,165,237 366,310 394,270 316,655 526,555 133,113 4,902,138 

238300 ..... Building Finishing Contractors .............. 34,628,392 2,874,918 2,623,763 5,950,757 3,156,004 1,025,405 50,259,239 

238900 ..... Other Specialty Trade Contractors ....... 43,159,424 4,044,680 5,878,597 4,854,336 7,251,924 2,815,017 68,003,978 

999000 ..... State and Local Governments [c] ......... 11,361,299 1,641,712 3,257,131 1,426,696 4,493,968 1,157,427 23,338,234 

Total—Construction .............................. 242,579,193 84,004,516 44,552,948 76,012,451 47,270,844 16,745,663 511,165,616 

Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on ERG (2013). 

1. Unit Costs, Other Cost Parameters, 

and Methodological Assumptions by 

Major Provision 

Below, OSHA summarizes its 

methodology for estimating unit and 

total costs for the major provisions 

required under the proposed silica 

standard. For a full presentation of the 

cost analysis, see Chapter V of the PEA 

and ERG (2007a, 2007b, 2011, 2013). 

OSHA invites comment on all aspects of 

its preliminary cost analysis. 

a. Engineering Controls 

Engineering controls include such 

measures as local exhaust ventilation, 

equipment hoods and enclosures, dust 

suppressants, spray booths and other 

forms of wet methods, high efficient 

particulate air (HEPA) vacuums, and 

control rooms. 

Following ERG’s (2011) methodology, 

OSHA estimated silica control costs on 

a per-worker basis, allowing the costs to 

be related directly to the estimates of the 

number of overexposed workers. OSHA 

then multiplied the estimated control 

cost per worker by the numbers of 

overexposed workers for both the 

proposed PEL of 50 mg/m3 and the 

alternative PEL of 100 mg/m3, 

introduced for economic analysis 

purposes. The numbers of workers 

needing controls (i.e., workers 

overexposed) are based on the exposure 

profiles for at-risk occupations 

developed in the technological 

feasibility analysis in Chapter IV of the 

PEA and estimates of the number of 

workers employed in these occupations 

developed in the industry profile in 

Chapter III of the PEA. This workerbased method is necessary because, 

even though the Agency has data on the 

number of firms in each affected 

industry, on the occupations and 

industrial activities with worker 

exposure to silica, on exposure profiles 

of at-risk occupations, and on the costs 

of controlling silica exposure for 

specific industrial activities, OSHA does 

not have a way to match up these data 

at the firm level. Nor does OSHA have 

facility-specific data on worker 

exposure to silica or even facilityspecific data on the level of activity 

involving worker exposure to silica. 

Thus, OSHA could not directly estimate 

per-affected-facility costs, but instead, 

first had to estimate aggregate 

compliance costs and then calculate the 

average per-affected-facility costs by 

dividing aggregate costs by the number 

of affected facilities. 

In general, OSHA viewed the extent to 

which exposure controls are already in 

place to be reflected in the distribution 

of overexposures among the affected 

workers. Thus, for example, if 50 

percent of workers in a given 

occupation are found to be overexposed 

relative to the proposed silica PEL, 

OSHA judged this equivalent to 50 

percent of facilities lacking the relevant 

exposure controls. The remaining 50 

percent of facilities are expected either 

to have installed the relevant controls or 

to engage in activities that do not 

require that the exposure controls be in 

place. OSHA recognizes that some 

facilities might have the relevant 

controls in place but are still unable, for 

whatever reason, to achieve the PEL 

under consideration. ERG’s review of 

the industrial hygiene literature and 

other source materials (as noted in ERG, 

2007b), however, suggest that the large 

majority of overexposed workers lack 

relevant controls. Thus, OSHA has 

generally assumed that overexposures 

occur due to the absence of suitable 

controls. This assumption results in an 

overestimate of costs since, in some 

cases, employers may merely need to 

upgrade or better maintain existing 

controls or to improve work practices 

rather than to install and maintain new 

controls. 

There are two situations in which the 

proportionality assumption may 

oversimplify the estimation of the costs 

of the needed controls. First, some 

facilities may have the relevant controls 

in place but are still unable, for 

whatever reason, to achieve the PEL 

under consideration for all employees. 

ERG’s review of the industrial hygiene 

literature and other source materials (as 

noted in ERG, 2007b, pg. 3–4), however, 

suggest that the large majority of 

overexposed workers lack relevant 

controls. Thus, OSHA has generally 

assumed that overexposures occur due 

to the absence of suitable controls. This 

assumption could, in some cases, result 

in an overestimate of costs where 

employers merely need to upgrade or 

better maintain existing controls or to 

improve work practices rather than to 

install and maintain new controls. 

Second, there may be situations where 

facilities do not have the relevant 

controls in place but nevertheless have 

only a fraction of all affected employees 

above the PEL. If, in such situations, an 

employer would have to install all the 

controls necessary to meet the PEL, 

OSHA may have underestimated the 

control costs. However, OSHA believes 

that, in general, employers could come 

into compliance by such methods as 

checking the work practices of the 

employee who is above the PEL or 

installing smaller amounts of LEV at 

costs that would be more or less 

proportional to the costs for all 

employees. Nevertheless there may be 

situations in which a complete set of 

controls would be necessary if even one 

employee in a work area is above the 

PEL. OSHA welcomes comment on the 

extent to which this approach may yield 

underestimates or overestimates of 

costs. 

At many workstations, employers 

must improve ventilation to reduce 

silica exposures. Ventilation 

improvements will take a variety of 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56362 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

17As a result, OSHA expects that establishments 

in general industry do not currently use respirators 

to comply with the current OSHA PEL for quartz 

of approximately 100 mg/m3. 

18OSHA’s derivation of the 56 percent current 

compliance rate in construction, in the context of 

the proposed silica rule, is described in Chapter V 

in the PEA. 

forms at different workstations and in 

different facilities and industries. The 

cost of ventilation enhancements 

generally reflects the expense of 

ductwork and other equipment for the 

immediate workstation or individual 

location and, potentially, the cost of 

incremental capacity system-wide 

enhancements and increased operation 

costs for the heating, ventilation, and air 

conditioning (HVAC) system for the 

facility. 

For a number of occupations, the 

technological feasibility analysis 

indicates that, in addition to ventilation, 

the use of wet methods, improved 

housekeeping practices, and enclosure 

of process equipment are needed to 

reduce silica exposures. The degree of 

incremental housekeeping depends 

upon how dusty the operations are and 

the applicability of HEPA vacuums or 

other equipment to the dust problem. 

The incremental costs for most such 

occupations arise due to the labor 

required for these additional 

housekeeping efforts. Because 

additional labor for housekeeping will 

be required on virtually every work shift 

by most of the affected occupations, the 

costs of housekeeping are substantial. 

Employers also need to purchase HEPA 

vacuums and must incur the ongoing 

costs of HEPA vacuum filters. To reduce 

silica exposures by enclosure of process 

equipment, such as in the use of 

conveyors near production workers in 

mineral processing, covers can be 

particularly effective where silicacontaining materials are transferred (and 

notable quantities of dust become 

airborne), or, as another example, where 

dust is generated, such as in sawing or 

grinding operations. 

For construction, ERG (2007a) defined 

silica dust control measures for each 

representative job as specified in Table 

1 of the proposed rule. Generally, these 

controls involve either a dust collection 

system or a water-spray approach (wet 

method) to capture and suppress the 

release of respirable silica dust. Wetmethod controls require a water source 

(e.g., tank) and hoses. The size of the 

tank varies with the nature of the job 

and ranges from a small handpressurized tank to a large tank for earth 

drilling operations. Depending on the 

tool, dust collection methods entail 

vacuum equipment, including a vacuum 

unit and hoses, and either a dust shroud 

or an extractor. For example, concrete 

grinding operations using hand-held 

tools require dust shroud adapters for 

each tool and a vacuum. The capacity of 

the vacuum depends on the type and 

size of tool being used. Some 

equipment, such as concrete floor 

grinders, comes with a dust collection 

system and a port for a vacuum hose. 

The estimates of control costs for those 

jobs using dust collection methods 

assume that an HEPA filter will be 

required. 

For each job, ERG estimated the 

annual cost of the appropriate controls 

and translated this cost to a daily 

charge. The unit costs for control 

equipment were based on price 

information collected from 

manufacturers and vendors. In some 

cases, control equipment costs were 

based on data on equipment rental 

charges. 

As noted above, included among the 

engineering controls in OSHA’s cost 

model are housekeeping and dustsuppression controls in general 

industry. For the maritime industry and 

for construction, abrasive blasting 

operations are expected to require the 

use of wet methods to control silica 

dust. 

Tables V–3, V–4, V–21, V–22, and V– 

31 in Chapter V of the PEA and Tables 

V–A–1 and V–A–2 in Appendix V–A 

provide details on the unit costs, other 

unit parameters, and methodological 

assumptions applied by OSHA to 

estimate engineering control costs. 

b. Respiratory Protection 

OSHA’s cost estimates assume that 

implementation of the recommended 

silica controls prevents workers in 

general industry and maritime from 

being exposed over the PEL in most 

cases. Specifically, based on its 

technological feasibility analysis, OSHA 

expects that the technical controls are 

adequate to keep silica exposures at or 

below the PEL for an alternative PEL of 

100 mg/m3 (introduced for economic 

analysis purposes).17 For the proposed 

50 mg/m3 PEL, OSHA’s feasibility 

analysis suggests that the controls that 

employers use, either because of 

technical limitations or imperfect 

implementation, might not be adequate 

in all cases to ensure that worker 

exposures in all affected job categories 

are at or below 50 mg/m3. For this 

preliminary cost analysis, OSHA 

estimates that ten percent of the at-risk 

workers in general industry would 

require respirators, at least occasionally, 

after the implementation of engineering 

controls to achieve compliance with the 

proposed PEL of 50 mg/m3. For workers 

in maritime, the only activity with silica 

exposures above the proposed PEL of 50 

mg/m3 is abrasive blasting, and maritime 

workers engaged in abrasive blasting are 

already required to use respirators 

under the existing OSHA ventilation 

standard (29 CFR 1910.94(a)). Therefore, 

OSHA has estimated no additional costs 

for maritime workers to use respirators 

as a result of the proposed silica rule. 

For construction, employers whose 

workers receive exposures above the 

PEL are assumed to adopt the 

appropriate task-specific engineering 

controls and, where required, 

respirators prescribed in Table 1 and 

under paragraph (g)(1) in the proposed 

standard. Respirator costs in the 

construction industry have been 

adjusted to take into account OSHA’s 

estimate (consistent with the findings 

from the NIOSH Respiratory Survey, 

2003) that 56 percent of establishments 

in the construction industry are already 

using respirators that would be in 

compliance with the proposed silica 

rule. 

ERG (2013) used respirator cost 

information from a 2003 OSHA 

respirator study to estimate the annual 

cost of $570 (in 2009 dollars) for a halfmask, non-powered, air-purifying 

respirator and $638 per year (in 2009 

dollars) for a full-face non-powered airpurifying respirator (ERG, 2003). These 

unit costs reflect the annualized cost of 

respirator use, including accessories 

(e.g., filters), training, fit testing, and 

cleaning. 

In addition to bearing the costs 

associated with the provision of 

respirators, employers will incur a cost 

burden to establish respirator programs. 

OSHA projects that this expense will 

involve an initial 8 hours for 

establishments with 500 or more 

employees and 4 hours for all other 

firms. After the first year, OSHA 

estimates that 20 percent of 

establishments would revise their 

respirator program every year, with the 

largest establishments (500 or more 

employees) expending 4 hours for 

program revision, and all other 

employers expending two hours for 

program revision. Consistent with the 

findings from the NIOSH Respiratory 

Survey (2003), OSHA estimates that 56 

percent of establishments in the 

construction industry that would 

require respirators to achieve 

compliance with the proposed PEL 

already have a respirator program.18

OSHA further estimates that 50 percent 

of firms in general industry and all 

maritime firms that would require 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56363 

respirators to achieve compliance 

already have a respirator program. 

c. Exposure Assessment 

Most establishments wishing to 

perform exposure monitoring will 

require the assistance of an outside 

consulting industrial hygienist (IH) to 

obtain accurate results. While some 

firms might already employ or train 

qualified staff, ERG (2007b) judged that 

the testing protocols are fairly 

challenging and that few firms have 

sufficiently skilled staff to eliminate the 

need for outside consultants. 

Table V–8 in the PEA shows the unit 

costs and associated assumptions used 

to estimate exposure assessment costs. 

Unit costs for exposure sampling 

include direct sampling costs, the costs 

of productivity losses, and 

recordkeeping costs, and, depending on 

establishment size, range from $225 to 

$412 per sample in general industry and 

maritime and from $228 to $415 per 

sample in construction. 

For costing purposes, based on ERG 

(2007b), OSHA estimated that there are 

four workers per work area. OSHA 

interpreted the initial exposure 

assessment as requiring first-year testing 

of at least one worker in each distinct 

job classification and work area who is, 

or may reasonably be expected to be, 

exposed to airborne concentrations of 

respirable crystalline silica at or above 

the action level. This may result in 

overestimated exposure assessment 

costs in construction because OSHA 

anticipates that many employers, aware 

that their operations currently expose 

their workers to silica levels above the 

PEL, will simply choose to comply with 

Table 1 and avoid the costs of 

conducting exposure assessments. 

For periodic monitoring, the proposed 

standard provides employers an option 

of assessing employee exposures either 

under a fixed schedule (paragraph 

(d)(3)(i)) or a performance-based 

schedule (paragraph (d)(3)(ii)). Under 

the fixed schedule, the proposed 

standard requires semi-annual sampling 

for exposures at or above the action 

level and quarterly sampling for 

exposures above the 50 mg/m3 PEL. 

Monitoring must be continued until the 

employer can demonstrate that 

exposures are no longer at or above the 

action level. OSHA used the fixed 

schedule option under the frequency-ofmonitoring requirements to estimate, for 

costing purposes, that exposure 

monitoring will be conducted (a) twice 

a year where initial or subsequent 

exposure monitoring reveals that 

employee exposures are at or above the 

action level but at or below the PEL, and 

(b) four times a year where initial or 

subsequent exposure monitoring reveals 

that employee exposures are above the 

PEL. 

As required under paragraph (d)(4) of 

the proposed rule, whenever there is a 

change in the production, process, 

control equipment, personnel, or work 

practices that may result in new or 

additional exposures at or above the 

action level or when the employer has 

any reason to suspect that a change may 

result in new or additional exposures at 

or above the action level, the employer 

must conduct additional monitoring. 

Based on ERG (2007a, 2007b), OSHA 

estimated that approximately 15 percent 

of workers whose initial exposure or 

subsequent monitoring was at or above 

the action level would undertake 

additional monitoring. 

A more detailed description of unit 

costs, other unit parameters, and 

methodological assumptions for 

exposure assessments is presented in 

Chapter V of the PEA. 

d. Medical Surveillance 

Paragraph (h) of the proposed 

standard requires an initial health 

screening and then triennial periodic 

screenings for workers exposed above 

the proposed PEL of 50 mg/m3 for 30 

days or more per year. ERG (2013) 

assembled information on 

representative unit costs for initial and 

periodic medical surveillance. Separate 

costs were estimated for current 

employees and for new hires as a 

function of the employment size (i.e., 1– 

19, 20–499, or 500+ employees) of 

affected establishments. Table V–10 in 

the PEA presents ERG’s unit cost data 

and modeling assumptions used by 

OSHA to estimate medical surveillance 

costs. 

In accordance with the paragraph 

(h)(2) of the proposed rule, the initial 

(baseline) medical examination would 

consist of (1) a medical and work 

history, (2) a physical examination with 

special emphasis on the respiratory 

system, (3) a chest X-ray that is 

interpreted according to guidelines of 

the International Labour Organization, 

(4) a pulmonary function test that meets 

certain criteria and is administered by 

spirometry technician with current 

certification from a NIOSH-approved 

spirometry course, (5) testing for latent 

tuberculosis (TB) infection, and (6) any 

other tests deemed appropriate by the 

physician or licensed health care 

professional (PLHCP). 

As shown in Table V–10 in the PEA, 

the estimated unit cost of the initial 

health screening for current employees 

in general industry and maritime ranges 

from approximately $378 to $397 and 

includes direct medical costs, the 

opportunity cost of worker time (i.e., 

lost work time, evaluated at the worker’s 

2009 hourly wage, including fringe 

benefits) for offsite travel and for the 

initial health screening itself, and 

recordkeeping costs. The variation in 

the unit cost of the initial health 

screening is due entirely to differences 

in the percentage of workers expected to 

travel offsite for the health screening. In 

OSHA’s experience, the larger the 

establishment the more likely it is that 

the selected PLHCP would provide the 

health screening services at the 

establishment’s worksite. OSHA 

estimates that 20 percent of 

establishments with fewer than 20 

employees, 75 percent of establishments 

with 20–499 employees, and 100 

percent of establishments with 500 or 

more employees would have the initial 

health screening for current employees 

conducted onsite. 

The unit cost components of the 

initial health screening for new hires in 

general industry and maritime are 

identical to those for existing employees 

with the exception that the percentage 

of workers expected to travel offsite for 

the health screening would be 

somewhat larger (due to fewer workers 

being screened annually, in the case of 

new hires, and therefore yielding fewer 

economies of onsite screening). OSHA 

estimates that 10 percent of 

establishments with fewer than 20 

employees, 50 percent of establishments 

with 20–499 employees, and 90 percent 

of establishments with 500 or more 

employees would have the initial health 

screening for new hires conducted 

onsite. As shown in Chapter V in the 

PEA, the estimated unit cost of the 

initial health screening for new hires in 

general industry and maritime ranges 

from approximately $380 to $399. 

The unit costs of medical surveillance 

in construction were derived using 

identical methods. As shown in Table 

V–39 of the PEA, the estimated unit 

costs of the initial health screening for 

current employees in construction range 

from approximately $389 to $425; the 

estimated unit costs of the initial health 

screening for new hires in construction 

range from approximately $394 to $429. 

In accordance with paragraph (h)(3) of 

the proposed rule, the periodic medical 

examination (every third year after the 

initial health screening) would consist 

of (1) a medical and work history review 

and update, (2) a physical examination 

with special emphasis on the respiratory 

system, (3) a chest X-ray that meets 

certain standards of the International 

Labour Organization, (4) a pulmonary 

function test that meets certain criteria 

and is administered by a spirometry 

technician with current certification 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56364 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

from a NIOSH-approved spirometry 

course, (5) testing for latent TB 

infection, if recommended by the 

PLHCP, and (6) any other tests deemed 

appropriate by the PLHCP. 

The estimated unit cost of periodic 

health screening also includes direct 

medical costs, the opportunity cost of 

worker time, and recordkeeping costs. 

As shown in Table V–10 in the PEA, 

these triennial unit costs in general 

industry and maritime vary from $378 

to $397. For construction, as shown in 

Table V–39 in the PEA, the triennial 

unit costs for periodic health screening 

vary from roughly $389 to $425. The 

variation in the unit cost (with or 

without the chest X-ray and pulmonary 

function test) is due entirely to 

differences in the percentage of workers 

expected to travel offsite for the periodic 

health screening. OSHA estimated that 

the share of workers traveling offsite, as 

a function of establishment size, would 

be the same for the periodic health 

screening as for the initial health 

screening for existing employees. 

ERG (2013) estimated a turnover rate 

of 27.2 percent in general industry and 

maritime and 64.0 percent in 

construction, based on estimates of the 

separations rate (layoffs, quits, and 

retirements) provided by the Bureau of 

Labor Statistics (BLS, 2007). However, 

not all new hires would require initial 

medical testing. As specified in 

paragraph (h)(2) of the proposed rule, 

employees who had received a 

qualifying medical examination within 

the previous twelve months would be 

exempt from the initial medical 

examination. OSHA estimates that 25 

percent of new hires in general industry 

and maritime and 60 percent of new 

hires in construction would be exempt 

from the initial medical examination. 

Although OSHA believes that some 

affected establishments in general 

industry, maritime, and construction 

currently provide some medical testing 

to their silica-exposed employees, the 

Agency doubts that many provide the 

comprehensive health screening 

required under the proposed rule. 

Therefore for costing purposes for the 

proposed rule, OSHA has assumed no 

current compliance with the proposed 

health screening requirements. OSHA 

requests information from interested 

parties on the current levels and the 

comprehensiveness of health screening 

in general industry, maritime, and 

construction. 

Finally, OSHA estimated the unit cost 

of a medical examination by a 

pulmonary specialist for those 

employees found to have signs or 

symptoms of silica-related disease or are 

otherwise referred by the PLHCP. OSHA 

estimates that a medical examination by 

a pulmonary specialist costs 

approximately $307 for workers in 

general industry and maritime and $333 

for workers in construction. This cost 

includes direct medical costs, the 

opportunity cost of worker time, and 

recordkeeping costs. In all cases, OSHA 

anticipates that the worker will travel 

offsite to receive the medical 

examination by a pulmonary specialist. 

See Chapter V in the PEA for a full 

discussion of OSHA’s analysis of 

medical surveillance costs under the 

proposed standard. 

e. Information and Training 

As specified in paragraph (i) of the 

proposed rule and 29 CFR 1910.1200, 

training is required for all employees in 

jobs where there is potential exposure to 

respirable crystalline silica. In addition, 

new hires would require training before 

starting work. As previously noted, ERG 

(2013) provided an estimate of the newhire rate in general industry and 

maritime, based on the BLS-estimated 

separations rate of 27.2 percent in 

manufacturing, and an estimate of the 

new-hire rate in construction, based on 

the BLS-estimated separations rate in 

construction of 64.0 percent. 

OSHA estimated separate costs for 

initial training of current employees and 

for training new hires. Given that newhire training might need to be 

performed frequently during the year, 

OSHA estimated a smaller class size for 

new hires. OSHA anticipates that 

training, in accordance with the 

requirements of the proposed rule, will 

be conducted by in-house safety or 

supervisory staff with the use of training 

modules or videos and will last, on 

average, one hour. ERG (2007b) judged 

that establishments could purchase 

sufficient training materials at an 

average cost of $2 per worker, 

encompassing the cost of handouts, 

video presentations, and training 

manuals and exercises. ERG (2013) 

included in the cost estimates for 

training the value of worker and trainer 

time as measured by 2009 hourly wage 

rates (to include fringe benefits). ERG 

also developed estimates of average 

class sizes as a function of 

establishment size. For initial training, 

ERG estimated an average class size of 

5 workers for establishments with fewer 

than 20 employees, 10 workers for 

establishments with 20 to 499 

employees, and 20 workers for 

establishments with 500 or more 

employees. For new hire training, ERG 

estimated an average class size of 2 

workers for establishments with fewer 

than 20 employees, 5 workers for 

establishments with 20 to 499 

employees, and 10 workers for 

establishments with 500 or more 

employees. 

The unit costs of training are 

presented in Tables V–14 (for general 

industry/maritime) and V–43 (for 

construction) in the PEA. Based on 

ERG’s work, OSHA estimated the 

annualized cost (annualized over 10 

years) of initial training per current 

employee at between $3.02 and $3.57 

and the annual cost of new-hire training 

at between $22.50 and $32.72 per 

employee in general industry and 

maritime, depending on establishment 

size. For construction, OSHA estimated 

the annualized cost of initial training 

per employee at between $3.68 and 

$4.37 and the annual cost of new hire 

training at between $27.46 and $40.39 

per employee, depending on 

establishment size. 

OSHA recognizes that many affected 

establishments currently provide 

training on the hazards of respirable 

crystalline silica in the workplace. 

Consistent with some estimates 

developed by ERG (2007a and 2007b), 

OSHA estimates that 50 percent of 

affected establishments already provide 

such training. However, some of the 

training specified in the proposed rule 

requires that workers be familiar with 

the training and medical surveillance 

provisions in the rule. OSHA expects 

that these training requirements in the 

proposed rule are not currently being 

provided. Therefore, for costing 

purposes for the proposed rule, OSHA 

has estimated that 50 percent of affected 

establishments currently provide their 

workers, and would provide new hires, 

with training that would comply with 

approximately 50 percent of the training 

requirements. In other words, OSHA 

estimates that those 50 percent of 

establishments currently providing 

training on workplace silica hazards 

would provide an additional 30 minutes 

of training to comply with the proposed 

rule; the remaining 50 percent of 

establishments would provide 60 

minutes of training to comply with the 

proposed rule. OSHA also recognizes 

that many new hires may have been 

previously employed in the same 

industry, and in some cases by the same 

establishment, so that they might have 

already received (partial) silica training. 

However, for purposes of cost 

estimation, OSHA estimates that all new 

hires will receive the full silica training 

from the new employer. OSHA requests 

comments from interested parties on the 

reasonableness of these assumptions. 

f. Regulated Areas and Access Control 

Paragraph (e)(1) of the proposed 

standard requires that wherever an 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56365 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica is, or can reasonably be expected 

to be, in excess of the PEL, each 

employer shall establish and implement 

either a regulated area in accordance 

with paragraph (e)(2) or an access 

control plan in accordance with 

paragraph (e)(3). For costing purposes, 

OSHA estimated that employers in 

general industry and maritime would 

typically prefer and choose option (e)(2) 

and would therefore establish regulated 

areas when an employee’s exposure to 

airborne concentrations of silica 

exceeds, or can reasonably be expected 

to exceed, the PEL. OSHA believes that 

general industry and maritime 

employers will prefer this option as it is 

expected to be the most practical 

alternative in fixed worksites. 

Requirements in the proposed rule for a 

regulated area include demarcating the 

boundaries of the regulated area (as 

separate from the rest of the workplace), 

limiting access to the regulated area, 

providing an appropriate respirator to 

each employee entering the regulated 

area, and providing protective clothing 

as needed in the regulated area. 

Based on ERG (2007b), OSHA derived 

unit cost estimates for establishing and 

maintaining regulated areas to comply 

with these requirements and estimated 

that one area would be necessary for 

every eight workers in general industry 

and maritime exposed above the PEL. 

Unit costs include planning time 

(estimated at eight hours of supervisor 

time annually); material costs for signs 

and boundary markers (annualized at 

$63.64 in 2009 dollars); and costs of 

$500 annually for two disposable 

respirators per day to be used by 

authorized persons (other than those 

who regularly work in the regulated 

area) who might need to enter the area 

in the course of their job duties. In 

addition, for costing purposes, OSHA 

estimates that, in response to the 

protective work clothing requirements 

in regulated areas, ten percent of 

employees in regulated areas would 

wear disposable protective clothing 

daily, estimated at $5.50 per suit, for an 

annual clothing cost of $1,100 per 

regulated area. Tables V–16 in the PEA 

shows the cost assumptions and unit 

costs applied in OSHA’s cost model for 

regulated areas in general industry and 

maritime. Overall, OSHA estimates that 

each regulated area would, on average, 

cost employers $1,732 annually in 

general industry and maritime. 

For construction, OSHA estimated 

that some employers would select the 

(e)(2) option concerning regulated areas 

while other employers would prefer the 

(e)(3) option concerning written access 

control plans whenever an employee’s 

exposure to airborne concentrations of 

respirable crystalline silica exceeds, or 

can reasonably be expected to exceed, 

the PEL. 

Based on the respirator specifications 

developed by ERG (2007a) and shown in 

Table V–34 in the PEA, ERG derived the 

full-time-equivalent number of workers 

engaged in construction tasks where 

respirators are required and estimated 

the costs of establishing a regulated area 

for these workers. 

Under the second option for written 

access control plans, the employer must 

include the following elements in the 

plan: competent person provisions; 

notification and demarcation 

procedures; multi-employer workplace 

procedures; provisions for limiting 

access; provisions for supplying 

respirators; and protective clothing 

procedures. OSHA anticipates that 

employers will incur costs for labor, 

materials, respiratory protection, and 

protective clothing to comply with the 

proposed access control plan 

requirements. 

Table V–45 in the PEA shows the unit 

costs and assumptions for developing 

costs for regulated areas and for access 

control plans in construction. ERG 

estimated separate development and 

implementation costs. ERG judged that 

developing either a regulated area or an 

access control plan would take 

approximately 4 hours of a supervisor’s 

time. The time allowed to set up a 

regulated area or an access control plan 

is intended to allow for the 

communication of access restrictions 

and locations at multi-employer 

worksites. ERG estimated a cost of $116 

per job based on job frequency and the 

costs for hazard tape and warning signs 

(which are reusable). ERG estimated a 

labor cost of $27 per job for 

implementing a written access control 

plan (covering the time expended for 

revision of the access control plan for 

individual jobs and communication of 

the plan). In addition, OSHA estimated 

that there would be annual disposable 

clothing costs of $333 per crew for 

employers who implement either 

regulated areas or the access control 

plan option. In addition, OSHA 

estimated that there would be annual 

respirator costs of $60 per crew for 

employers who implement either 

option. 

ERG aggregated costs by estimating an 

average crew size of four in construction 

and an average job length of ten days. 

ERG judged that employers would 

choose to establish regulated areas in 75 

percent of the instances where either 

regulated areas or an access control plan 

is required, and that written access 

control plans would be established for 

the remaining 25 percent. 

See Chapter V in the PEA for a full 

discussion of OSHA’s analysis of costs 

for regulated areas and written access 

control plans under the proposed 

standard. 

F. Economic Feasibility Analysis and 

Regulatory Flexibility Determination 

Chapter VI of the PEA presents 

OSHA’s analysis of the economic 

impacts of its proposed silica rule on 

affected employers in general industry, 

maritime, and construction. The 

discussion below summarizes the 

findings in that chapter. 

As a first step, the Agency explains its 

approach for achieving the two major 

objectives of its economic impact 

analysis: (1) To establish whether the 

proposed rule is economically feasible 

for all affected industries, and (2) to 

determine if the Agency can certify that 

the proposed rule will not have a 

significant economic impact on a 

substantial number of small entities. 

Next, this approach is applied to 

industries with affected employers in 

general industry and maritime and then 

to industries with affected employers in 

construction. Finally, OSHA directed 

Inforum—a not-for-profit corporation 

(based at the University of Maryland) 

specializing in the design and 

application of macroeconomic models 

of the United States (and other 

countries)—to estimate the industry and 

aggregate employment effects of the 

proposed silica rule. The Agency invites 

comment on any aspect of the methods 

and data presented here or in Chapter VI 

of the PEA. 

1. Analytic Approach 

a. Economic Feasibility 

The Court of Appeals for the D.C. 

Circuit has long held that OSHA 

standards are economically feasible so 

long as their costs do not threaten the 

existence of, or cause massive economic 

dislocations within, a particular 

industry or alter the competitive 

structure of that industry. American 

Iron and Steel Institute. v. OSHA, 939 

F.2d 975, 980 (D.C. Cir. 1991); United 

Steelworkers of America, AFL–CIO–CLC 

v. Marshall, 647 F.2d 1189, 1265 (D.C. 

Cir. 1980); Industrial Union Department 

v. Hodgson, 499 F.2d 467, 478 (D.C. Cir. 

1974). 

In practice, the economic burden of 

an OSHA standard on an industry—and 

whether the standard is economically 

feasible for that industry—depends on 

the magnitude of compliance costs 

incurred by establishments in that 

industry and the extent to which they 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56366 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

are able to pass those costs on to their 

customers. That, in turn, depends, to a 

significant degree, on the price elasticity 

of demand for the products sold by 

establishments in that industry. 

The price elasticity of demand refers 

to the relationship between the price 

charged for a product and the demand 

for that product: the more elastic the 

relationship, the less an establishment’s 

compliance costs can be passed through 

to customers in the form of a price 

increase and the more it has to absorb 

compliance costs in the form of reduced 

profits. When demand is inelastic, 

establishments can recover most of the 

costs of compliance by raising the prices 

they charge; under this scenario, profit 

rates are largely unchanged and the 

industry remains largely unaffected. 

Any impacts are primarily on those 

customers using the relevant product. 

On the other hand, when demand is 

elastic, establishments cannot recover 

all compliance costs simply by passing 

the cost increase through in the form of 

a price increase; instead, they must 

absorb some of the increase from their 

profits. Commonly, this will mean 

reductions both in the quantity of goods 

and services produced and in total 

profits, though the profit rate may 

remain unchanged. In general, ‘‘[w]hen 

an industry is subjected to a higher cost, 

it does not simply swallow it; it raises 

its price and reduces its output, and in 

this way shifts a part of the cost to its 

consumers and a part to its suppliers,’’ 

in the words of the court in American 

Dental Association v. Secretary of Labor 

(984 F.2d 823, 829 (7th Cir. 1993)). 

The court’s summary is in accord 

with microeconomic theory. In the long 

run, firms can remain in business only 

if their profits are adequate to provide 

a return on investment that ensures that 

investment in the industry will 

continue. Over time, because of rising 

real incomes and productivity increases, 

firms in most industries are able to 

ensure an adequate profit. As 

technology and costs change, however, 

the long-run demand for some products 

naturally increases and the long-run 

demand for other products naturally 

decreases. In the face of additional 

compliance costs (or other external 

costs), firms that otherwise have a 

profitable line of business may have to 

increase prices to stay viable. Increases 

in prices typically result in reduced 

quantity demanded, but rarely eliminate 

all demand for the product. Whether 

this decrease in the total production of 

goods and services results in smaller 

output for each establishment within 

the industry or the closure of some 

plants within the industry, or a 

combination of the two, is dependent on 

the cost and profit structure of 

individual firms within the industry. 

If demand is perfectly inelastic (i.e., 

the price elasticity of demand is zero), 

then the impact of compliance costs that 

are 1 percent of revenues for each firm 

in the industry would result in a 1 

percent increase in the price of the 

product, with no decline in quantity 

demanded. Such a situation represents 

an extreme case, but might be observed 

in situations in which there were few if 

any substitutes for the product in 

question, or if the products of the 

affected sector account for only a very 

small portion of the revenue or income 

of its customers. 

If the demand is perfectly elastic (i.e., 

the price elasticity of demand is 

infinitely large), then no increase in 

price is possible and before-tax profits 

would be reduced by an amount equal 

to the costs of compliance (net of any 

cost savings—such as reduced workers’ 

compensation insurance premiums— 

resulting from the proposed standard) if 

the industry attempted to maintain 

production at the same level as 

previously. Under this scenario, if the 

costs of compliance are such a large 

percentage of profits that some or all 

plants in the industry could no longer 

operate in the industry with hope of an 

adequate return on investment, then 

some or all of the firms in the industry 

would close. This scenario is highly 

unlikely to occur, however, because it 

can only arise when there are other 

products—unaffected by the proposed 

rule—that are, in the eyes of their 

customers, perfect substitutes for the 

products the affected establishments 

make. 

A common intermediate case would 

be a price elasticity of demand of one 

(in absolute terms). In this situation, if 

the costs of compliance amount to 1 

percent of revenues, then production 

would decline by 1 percent and prices 

would rise by 1 percent. As a result, 

industry revenues would remain the 

same, with somewhat lower production, 

but with similar profit rates (in most 

situations where the marginal costs of 

production net of regulatory costs 

would fall as well). Customers would, 

however, receive less of the product for 

their (same) expenditures, and firms 

would have lower total profits; this, as 

the court described in American Dental 

Association v. Secretary of Labor, is the 

more typical case. 

A decline in output as a result of an 

increase in price may occur in a variety 

of ways: individual establishments 

could each reduce their levels of 

production; some marginal plants could 

close; or, in the case of an expanding 

industry, new entry may be delayed 

until demand equals supply. In many 

cases it will be a combination of all 

three kinds of reductions in output. 

Which possibility is most likely 

depends on the form that the costs of 

the regulation take. If the costs are 

variable costs (i.e., costs that vary with 

the level of production at a facility), 

then economic theory suggests that any 

reductions in output will take the form 

of reductions in output at each affected 

facility, with few if any plant closures. 

If, on the other hand, the costs of a 

regulation primarily take the form of 

fixed costs (i.e., costs that do not vary 

with the level of production at a 

facility), then reductions in output are 

more likely to take the form of plant 

closures or delays in new entry. 

Most of the costs of this regulation, as 

estimated in Chapter V of the PEA, are 

variable costs. Almost all of the major 

costs of program elements, such as 

medical surveillance and training, will 

vary in proportion to the number of 

employees (which is a rough proxy for 

the amount of production). Exposure 

monitoring costs will vary with the 

number of employees, but do have some 

economies of scale to the extent that a 

larger firm need only conduct 

representative sampling rather than 

sample every employee. The costs of 

engineering controls in construction 

also vary by level of production because 

almost all necessary equipment can 

readily be rented and the productivity 

costs of using some of these controls 

vary proportionally to the level of 

production. Finally, the costs of 

operating engineering controls in 

general industry (the majority of the 

annualized costs of engineering controls 

in general industry) vary by the number 

of hours the establishment works, and 

thus vary by the level of production and 

are not fixed costs in the strictest sense. 

This leaves two kinds of costs that 

are, in some sense, fixed costs—capital 

costs of engineering controls in general 

industry and certain initial costs that 

new entries to the industry will not 

have to bear. 

Capital costs of engineering controls 

in general industry due to this standard 

are relatively small as compared to the 

total costs, representing less than 8 

percent of total annualized costs and 

approximately $362 per year per 

affected establishment in general 

industry. 

Some initial costs are fixed in the 

sense that they will only be borne by 

firms in the industry today—these 

include initial costs for general training 

not currently required and initial costs 

of medical surveillance. Both of these 

costs will disappear after the initial year 

of the standard and thus would be 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56367 

19See OSHA’s Web page, http://www.osha.gov/

dea/lookback.html#Completed, for a link to all 

completed OSHA lookback reviews. 

difficult to pass on. These costs, 

however, represent less than 4 percent 

of total costs and less than $55 per 

affected establishment. 

As a result of these considerations, 

OSHA expects that it is somewhat more 

likely that reductions in industry output 

will be met by reductions in output at 

each affected facility rather than as a 

result of plant closures. However, 

closures of some marginal plants or 

poorly performing facilities are always 

possible. 

To determine whether a rule is 

economically feasible, OSHA begins 

with two screening tests to consider 

minimum threshold effects of the rule 

under two extreme cases: (1) all costs 

are passed through to customers in the 

form of higher prices (consistent with a 

price elasticity of demand of zero), and 

(2) all costs are absorbed by the firm in 

the form of reduced profits (consistent 

with an infinite price elasticity of 

demand). 

In the former case, the immediate 

impact of the rule would be observed in 

increased industry revenues. While 

there is no hard and fast rule, in the 

absence of evidence to the contrary, 

OSHA generally considers a standard to 

be economically feasible for an industry 

when the annualized costs of 

compliance are less than a threshold 

level of one percent of annual revenues. 

Retrospective studies of previous OSHA 

regulations have shown that potential 

impacts of such a small magnitude are 

unlikely to eliminate an industry or 

significantly alter its competitive 

structure,19 particularly since most 

industries have at least some ability to 

raise prices to reflect increased costs 

and, as shown in the PEA, normal price 

variations for products typically exceed 

three percent a year. Of course, OSHA 

recognizes that even when costs are 

within this range, there could be 

unusual circumstances requiring further 

analysis. 

In the latter case, the immediate 

impact of the rule would be observed in 

reduced industry profits. OSHA uses the 

ratio of annualized costs to annual 

profits as a second check on economic 

feasibility. Again, while there is no hard 

and fast rule, in the absence of evidence 

to the contrary, OSHA has historically 

considered a standard to be 

economically feasible for an industry 

when the annualized costs of 

compliance are less than a threshold 

level of ten percent of annual profits. In 

the context of economic feasibility, the 

Agency believes this threshold level to 

be fairly modest, given that—as shown 

in the PEA—normal year-to-year 

variations in profit rates in an industry 

can exceed 40 percent or more. OSHA’s 

choice of a threshold level of ten 

percent of annual profits is low enough 

that even if, in a hypothetical worst 

case, all compliance costs were upfront 

costs, then upfront costs would still 

equal seventy-one percent of profits and 

thus would be affordable from profits 

without resort to credit markets. If the 

threshold level were first-year costs of 

ten percent of annual profits, firms 

could even more easily expect to cover 

first-year costs at the threshold level out 

of current profits without having to 

access capital markets and otherwise 

being threatened with short-term 

insolvency. 

In general, because it is usually the 

case that firms would able to pass on 

some or all of the costs of the proposed 

rule, OSHA will tend to give much more 

weight to the ratio of industry costs to 

industry revenues than to the ratio of 

industry costs to industry profits. 

However, if costs exceed either the 

threshold percentage of revenue or the 

threshold percentage of profits for an 

industry, or if there is other evidence of 

a threat to the viability of an industry 

because of the standard, OSHA will 

examine the effect of the rule on that 

industry more closely. Such an 

examination would include market 

factors specific to the industry, such as 

normal variations in prices and profits, 

international trade and foreign 

competition, and any special 

circumstances, such as close domestic 

substitutes of equal cost, which might 

make the industry particularly 

vulnerable to a regulatory cost increase. 

The preceding discussion focused on 

the economic viability of the affected 

industries in their entirety. However, 

even if OSHA found that a proposed 

standard did not threaten the survival of 

affected industries, there is still the 

question of whether the industries’ 

competitive structure would be 

significantly altered. For this reason, 

OSHA also examines the differential 

costs by size of firm. 

b. Regulatory Flexibility Screening 

Analysis 

The Regulatory Flexibility Act (RFA), 

Pub. L. No. 96–354, 94 Stat. 1164 

(codified at 5 U.S.C. 601), requires 

Federal agencies to consider the 

economic impact that a proposed 

rulemaking will have on small entities. 

The RFA states that whenever a Federal 

agency is required to publish general 

notice of proposed rulemaking for any 

proposed rule, the agency must prepare 

and make available for public comment 

an initial regulatory flexibility analysis 

(IRFA). 5 U.S.C. 603(a). Pursuant to 

section 605(b), in lieu of an IRFA, the 

head of an agency may certify that the 

proposed rule will not have a significant 

economic impact on a substantial 

number of small entities. A certification 

must be supported by a factual basis. If 

the head of an agency makes a 

certification, the agency shall publish 

such certification in the Federal 

Register at the time of publication of 

general notice of proposed rulemaking 

or at the time of publication of the final 

rule. 5 U.S.C. 605(b). 

To determine if the Assistant 

Secretary of Labor for OSHA can certify 

that the proposed silica rule will not 

have a significant economic impact on 

a substantial number of small entities, 

the Agency has developed screening 

tests to consider minimum threshold 

effects of the proposed rule on small 

entities. These screening tests are 

similar in concept to those OSHA 

developed above to identify minimum 

threshold effects for purposes of 

demonstrating economic feasibility. 

There are, however, two differences. 

First, for each affected industry, the 

screening tests are applied, not to all 

establishments, but to small entities 

(defined as ‘‘small business concerns’’ 

by SBA) and also to very small entities 

(defined by OSHA as entities with fewer 

than 20 employees). Second, although 

OSHA’s regulatory flexibility screening 

test for revenues also uses a minimum 

threshold level of annualized costs 

equal to one percent of annual revenues, 

OSHA has established a minimum 

threshold level of annualized costs 

equal to five percent of annual profits 

for the average small entity or very 

small entity. The Agency has chosen a 

lower minimum threshold level for the 

profitability screening analysis and has 

applied its screening tests to both small 

entities and very small entities in order 

to ensure that certification will be made, 

and an IRFA will not be prepared, only 

if OSHA can be highly confident that a 

proposed rule will not have a significant 

economic impact on a substantial 

number of small entities in any affected 

industry. 

2. Impacts in General Industry and 

Maritime 

a. Economic Feasibility Screening 

Analysis: All Establishments 

To determine whether the proposed 

rule’s projected costs of compliance 

would threaten the economic viability 

of affected industries, OSHA first 

compared, for each affected industry, 

annualized compliance costs to annual 

revenues and profits per (average) 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56368 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

affected establishment. The results for 

all affected establishments in all 

affected industries in general industry 

and maritime are presented in Table 

VIII–11, using annualized costs per 

establishment for the proposed 50 mg/m3

PEL. Shown in the table for each 

affected industry are total annualized 

costs, the total number of affected 

establishments, annualized costs per 

affected establishment, annual revenues 

per establishment, the profit rate, 

annual profits per establishment, 

annualized compliance costs as a 

percentage of annual revenues, and 

annualized compliance costs as a 

percentage of annual profits. 

The annualized costs per affected 

establishment for each affected industry 

were calculated by distributing the 

industry-level (incremental) annualized 

compliance costs among all affected 

establishments in the industry, where 

costs were annualized using a 7 percent 

discount rate. The annualized cost of 

the proposed rule for the average 

establishment in all of general industry 

and maritime is estimated at $2,571 in 

2009 dollars. It is clear from Table VIII– 

11 that the estimates of the annualized 

costs per affected establishment in 

general industry and maritime vary 

widely from industry to industry. These 

estimates range from $40,468 for NAICS 

327111 (Vitreous china plumbing 

fixtures and bathroom accessories 

manufacturing) and $38,422 for NAICS 

327121 (Brick and structural clay 

manufacturing) to $107 for NAICS 

325510 (Paint and coating 

manufacturing) and $49 for NAICS 

621210 (Dental offices). 

Table VIII–11 also shows that, within 

the general industry and maritime 

sectors, there are no industries in which 

the annualized costs of the proposed 

rule exceed 1 percent of annual 

revenues or 10 percent of annual profits. 

NAICS 327123 (Other structural clay 

product manufacturing) has both the 

highest cost impact as a percentage of 

revenues, of 0.39 percent, and the 

highest cost impact as a percentage of 

profits, of 8.78 percent. Based on these 

results, even if the costs of the proposed 

rule were 50 percent higher than OSHA 

has estimated, the highest cost impact as 

a percentage of revenues in any affected 

industry in general industry or maritime 

would be less than 0.6 percent. 

Furthermore, the costs of the proposed 

rule would have to be more than 150 

percent higher than OSHA has 

estimated for the cost impact as a 

percentage of revenues to equal 1 

percent in any affected industry. For all 

affected establishments in general 

industry and maritime, the estimated 

annualized cost of the proposed rule is, 

on average, equal to 0.02 percent of 

annual revenue and 0.5 percent of 

annual profit. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56369 

TABLE VIII–11—SCREENING

ANALYSIS FOR

ESTABLISHMENTS IN

GENERAL INDUSTRY AND

MARITIME

AFFECTED BY OSHA’

S

PROPOSED

SILICA

STANDARD

NAICS Industry 

Total 

annualized 

costs 

Number of affected establishments Annualized costs per af- fected estab- lishment Revenues per establishment Profit rate a (percent) Profits per es- tablishment Costs as a per- centage of rev- enues Costs as a per- centage of prof- its 

324121 ..... Asphalt paving mixture and block manufacturing ........ $242,070 1,431 $169 $6,617,887 7.50 $496,420 0.00 0.03 324122 ..... Asphalt shingle and roofing materials .......................... 3,157,257 224 14,095 34,018,437 7.50 2,551,788 0.04 0.55 325510 ..... Paint and coating manufacturing ................................. 144,281 1,344 107 19,071,850 5.38 1,026,902 0.00 0.01 327111 ..... Vitreous china plumbing fixtures & bathroom accessories manufacturing. 1,659,194 41 40,468 21,226,709 4.41 937,141 0.19 4.32 327112 ..... Vitreous china, fine earthenware, & other pottery 

product manufacturing.

2,601,471 731 3,559 1,203,017 4.41 53,112 0.30 6.70 

327113 ..... Porcelain electrical supply mfg .................................... 1,748,297 125 13,986 8,091,258 4.41 357,222 0.17 3.92 327121 ..... Brick and structural clay mfg ....................................... 7,838,050 204 38,422 11,440,887 4.41 505,105 0.34 7.61 327122 ..... Ceramic wall and floor tile mfg .................................... 4,132,107 193 21,410 6,706,175 4.41 296,072 0.32 7.23 327123 ..... Other structural clay product mfg ................................ 936,699 49 19,116 4,933,258 4.41 217,799 0.39 8.78 327124 ..... Clay refractory manufacturing ...................................... 482,438 129 3,740 7,872,516 4.41 347,565 0.05 1.08 327125 ..... Nonclay refractory manufacturing ................................ 608,017 105 5,791 14,718,533 4.41 649,810 0.04 0.89 327211 ..... Flat glass manufacturing .............................................. 275,155 83 3,315 43,821,692 3.42 1,499,102 0.01 0.22 327212 ..... Other pressed and blown glass and glassware manufacturing. 1,084,706 499 2,174 7,233,509 3.42 247,452 0.03 0.88 327213 ..... Glass container manufacturing .................................... 756,888 72 10,512 64,453,615 3.42 2,204,903 0.02 0.48 327320 ..... Ready-mixed concrete manufacturing ......................... 16,511,080 6,064 2,723 4,891,554 6.64 324,706 0.06 0.84 327331 ..... Concrete block and brick mfg ...................................... 4,437,939 951 4,667 5,731,328 6.64 380,451 0.08 1.23 327332 ..... Concrete pipe mfg ........................................................ 2,747,484 385 7,136 7,899,352 6.64 524,366 0.09 1.36 327390 ..... Other concrete product mfg ......................................... 12,900,251 2,281 5,656 4,816,851 6.64 319,747 0.12 1.77 327991 ..... Cut stone and stone product manufacturing ............... 8,600,298 1,943 4,426 1,918,745 5.49 105,320 0.23 4.20 327992 ..... Ground or treated mineral and earth manufacturing ... 4,595,006 271 16,956 8,652,610 5.49 474,944 0.20 3.57 327993 ..... Mineral wool manufacturing ......................................... 1,094,552 321 3,410 18,988,835 5.49 1,042,303 0.02 0.33 327999 ..... All other misc. nonmetallic mineral product mfg .......... 1,966,052 465 4,228 5,803,139 5.49 318,536 0.07 1.33 331111 ..... Iron and steel mills ....................................................... 424,557 614 692 70,641,523 4.49 3,173,209 0.00 0.02 331112 ..... Electrometallurgical ferroalloy product manufacturing 8,577 12 692 49,659,392 4.49 2,230,694 0.00 0.03 331210 ..... Iron and steel pipe and tube manufacturing from purchased steel. 84,537 122 694 31,069,797 4.49 1,395,652 0.00 0.05 331221 ..... Rolled steel shape manufacturing ............................... 42,672 61 694 28,102,003 4.49 1,262,339 0.00 0.05 331222 ..... Steel wire drawing ........................................................ 57,557 83 694 12,904,028 4.49 579,647 0.01 0.12 331314 ..... Secondary smelting and alloying of aluminum ............ 28,757 42 692 29,333,260 4.46 1,309,709 0.00 0.05 331423 ..... Secondary smelting, refining, and alloying of copper .. 4,940 7 695 26,238,546 4.42 1,158,438 0.00 0.06 331492 ..... Secondary smelting, refining, and alloying of nonferrous metal (except cu & al). 36,946 53 695 14,759,299 4.42 651,626 0.00 0.11 331511 ..... Iron foundries ............................................................... 15,310,815 527 29,053 19,672,534 4.11 809,290 0.15 3.59 331512 ..... Steel investment foundries ........................................... 4,283,138 132 32,448 18,445,040 4.11 758,794 0.18 4.28 331513 ..... Steel foundries (except investment) ............................ 4,596,837 222 20,706 17,431,292 4.11 717,090 0.12 2.89 331524 ..... Aluminum foundries (except die-casting) ..................... 6,975,150 466 14,968 8,244,396 4.11 339,159 0.18 4.41 331525 ..... Copper foundries (except die-casting) ......................... 1,636,463 256 6,392 3,103,580 4.11 127,675 0.21 5.01 331528 ..... Other nonferrous foundries (except die-casting) ......... 1,232,708 124 9,941 7,040,818 4.11 289,646 0.14 3.43 332111 ..... Iron and steel forging ................................................... 105,955 150 705 15,231,376 4.71 716,646 0.00 0.10 332112 ..... Nonferrous forging ....................................................... 34,982 50 705 28,714,500 4.71 1,351,035 0.00 0.05 332115 ..... Crown and closure manufacturing ............................... 12,720 18 697 16,308,872 4.71 767,343 0.00 0.09 332116 ..... Metal stamping ............................................................. 255,832 366 700 6,748,606 4.71 317,526 0.01 0.22 332117 ..... Powder metallurgy part manufacturing ........................ 32,828 47 696 9,712,731 4.71 456,990 0.01 0.15 332211 ..... Cutlery and flatware (except precious) manufacturing 22,970 33 705 9,036,720 5.22 472,045 0.01 0.15 332212 ..... Hand and edge tool manufacturing ............................. 145,223 207 702 5,874,133 5.22 306,843 0.01 0.23 332213 ..... Saw blade and handsaw manufacturing ...................... 28,851 41 698 11,339,439 5.22 592,331 0.01 0.12 332214 ..... Kitchen utensil, pot, and pan manufacturing ............... 15,678 22 705 18,620,983 5.22 972,693 0.00 0.07 332323 ..... Ornamental and architectural metal work .................... 35,267 54 654 2,777,899 4.70 130,669 0.02 0.50 332439 ..... Other metal container manufacturing .......................... 60,330 86 705 7,467,745 3.58 267,613 0.01 0.26 332510 ..... Hardware manufacturing .............................................. 180,292 256 705 11,899,309 5.22 621,577 0.01 0.11 332611 ..... Spring (heavy gauge) manufacturing ........................... 16,158 23 705 7,764,934 5.22 405,612 0.01 0.17 332612 ..... Spring (light gauge) manufacturing .............................. 60,992 87 705 8,185,896 5.22 427,602 0.01 0.16 332618 ..... Other fabricated wire product manufacturing .............. 144,819 205 705 5,120,358 5.22 267,469 0.01 0.26 332710 ..... Machine shops ............................................................. 1,077,759 1,506 716 1,624,814 5.80 94,209 0.04 0.76 332812 ..... Metal coating and allied services ................................. 3,038,935 2,599 1,169 4,503,334 4.85 218,618 0.03 0.53 332911 ..... Industrial valve manufacturing ..................................... 150,261 216 694 18,399,215 6.81 1,252,418 0.00 0.06 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56370 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–11—SCREENING

ANALYSIS FOR

ESTABLISHMENTS IN

GENERAL INDUSTRY AND

MARITIME

AFFECTED BY OSHA’

S

PROPOSED

SILICA

STANDARD— 

Continued 

NAICS Industry 

Total 

annualized 

costs 

Number of affected establishments Annualized costs per af- fected estab- lishment Revenues per establishment Profit rate a (percent) Profits per es- tablishment Costs as a per- centage of rev- enues Costs as a per- centage of prof- its 

332912 ..... Fluid power valve and hose fitting manufacturing ....... 140,213 201 698 22,442,750 6.81 1,527,658 0.00 0.05 332913 ..... Plumbing fixture fitting and trim manufacturing ........... 45,472 65 698 24,186,039 6.81 1,646,322 0.00 0.04 332919 ..... Other metal valve and pipe fitting manufacturing ........ 71,354 102 698 15,023,143 6.81 1,022,612 0.00 0.07 332991 ..... Ball and roller bearing manufacturing .......................... 107,338 154 698 36,607,380 6.81 2,491,832 0.00 0.03 332996 ..... Fabricated pipe and pipe fitting manufacturing ........... 107,219 154 698 6,779,536 6.81 461,477 0.01 0.15 332997 ..... Industrial pattern manufacturing .................................. 20,891 30 698 1,122,819 6.81 76,429 0.06 0.91 332998 ..... Enameled iron and metal sanitary ware manufacturing. 60,684 76 798 14,497,312 6.81 986,819 0.01 0.08 332999 ..... All other miscellaneous fabricated metal product manufacturing. 288,093 408 707 4,405,921 6.81 299,907 0.02 0.24 333319 ..... Other commercial and service industry machinery 

manufacturing.

209,273 299 699 10,042,625 4.86 487,919 0.01 0.14 

333411 ..... Air purification equipment manufacturing .................... 58,265 84 694 7,353,577 4.55 334,804 0.01 0.21 333412 ..... Industrial and commercial fan and blower manufacturing. 41,212 59 694 12,795,249 4.55 582,559 0.01 0.12 333414 ..... Heating equipment (except warm air furnaces) manufacturing. 80,754 116 694 11,143,189 4.55 507,342 0.01 0.14 333511 ..... Industrial mold manufacturing ...................................... 160,131 226 710 2,481,931 5.29 131,278 0.03 0.54 333512 ..... Machine tool (metal cutting types) manufacturing ....... 68,151 97 702 7,371,252 5.29 389,890 0.01 0.18 333513 ..... Machine tool (metal forming types) manufacturing ..... 33,940 48 702 5,217,940 5.29 275,994 0.01 0.25 333514 ..... Special die and tool, die set, jig, and fixture manufacturing. 231,988 325 714 2,378,801 5.29 125,823 0.03 0.57 333515 ..... Cutting tool and machine tool accessory manufacturing. 139,916 197 710 3,384,805 5.29 179,034 0.02 0.40 333516 ..... Rolling mill machinery and equipment manufacturing 12,279 17 710 9,496,141 5.29 502,283 0.01 0.14 333518 ..... Other metalworking machinery manufacturing ............ 50,002 70 710 7,231,602 5.29 382,504 0.01 0.19 333612 ..... Speed changer, industrial high-speed drive, and gear 

manufacturing.

48,452 70 693 10,727,834 2.63 281,813 0.01 0.25 

333613 ..... Mechanical power transmission equipment manufacturing. 61,197 88 693 14,983,120 2.63 393,597 0.00 0.18 333911 ..... Pump and pumping equipment manufacturing ............ 121,086 174 696 17,078,357 4.58 781,566 0.00 0.09 333912 ..... Air and gas compressor manufacturing ....................... 84,518 121 698 21,079,073 4.58 964,653 0.00 0.07 333991 ..... Power-driven handtool manufacturing ......................... 34,459 49 698 22,078,371 4.58 1,010,384 0.00 0.07 333992 ..... Welding and soldering equipment manufacturing ....... 62,401 90 696 16,457,683 4.58 753,162 0.00 0.09 333993 ..... Packaging machinery manufacturing ........................... 83,714 120 700 7,374,940 4.58 337,503 0.01 0.21 333994 ..... Industrial process furnace and oven manufacturing .... 42,523 61 702 5,584,460 4.58 255,565 0.01 0.27 333995 ..... Fluid power cylinder and actuator manufacturing ........ 78,057 112 695 13,301,790 4.58 608,737 0.01 0.11 333996 ..... Fluid power pump and motor manufacturing ............... 53,535 77 695 18,030,122 4.58 825,122 0.00 0.08 333997 ..... Scale and balance (except laboratory) manufacturing 14,822 21 702 7,236,854 4.58 331,184 0.01 0.21 333999 ..... All other miscellaneous general purpose machinery 

manufacturing.

207,006 296 698 6,033,776 4.58 276,127 0.01 0.25 

334518 ..... Watch, clock, and part manufacturing ......................... 8,740 12 703 4,924,986 5.94 292,667 0.01 0.24 335211 ..... Electric housewares and household fans .................... 13,928 22 643 22,023,076 4.21 927,874 0.00 0.07 335221 ..... Household cooking appliance manufacturing .............. 30,077 47 643 37,936,003 4.21 1,598,316 0.00 0.04 335222 ..... Household refrigerator and home freezer manufacturing. 32,118 26 1,235 188,132,355 4.21 7,926,376 0.00 0.02 335224 ..... Household laundry equipment manufacturing ............. 30,521 23 1,327 221,491,837 4.21 9,331,875 0.00 0.01 335228 ..... Other major household appliance manufacturing ........ 24,023 37 643 107,476,620 4.21 4,528,196 0.00 0.01 336111 ..... Automobile manufacturing ........................................... 293,357 181 1,621 512,748,675 2.04 10,462,470 0.00 0.02 336112 ..... Light truck and utility vehicle manufacturing ................ 404,778 94 4,306 1,581,224,101 2.04 32,264,364 0.00 0.01 336120 ..... Heavy duty truck manufacturing .................................. 125,181 95 1,318 194,549,998 2.04 3,969,729 0.00 0.03 336211 ..... Motor vehicle body manufacturing ............................... 187,131 269 696 15,012,805 2.04 306,331 0.00 0.23 336212 ..... Truck trailer manufacturing .......................................... 126,512 182 694 17,032,455 2.04 347,542 0.00 0.20 336213 ..... Motor home manufacturing .......................................... 84,073 91 924 65,421,325 2.04 1,334,901 0.00 0.07 336311 ..... Carburetor, piston, piston ring, and valve manufacturing. 41,219 60 693 21,325,990 2.04 435,150 0.00 0.16 336312 ..... Gasoline engine and engine parts manufacturing ....... 258,625 373 693 36,938,061 2.04 753,709 0.00 0.09 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56371 

336322 ..... Other motor vehicle electrical and electronic equipment manufacturing. 242,586 350 693 33,890,776 2.04 691,530 0.00 0.10 336330 ..... Motor vehicle steering and suspension components 

(except spring) manufacturing.

153,960 223 692 42,374,501 2.04 864,638 0.00 0.08 

336340 ..... Motor vehicle brake system manufacturing ................. 132,114 191 693 51,498,927 2.04 1,050,819 0.00 0.07 336350 ..... Motor vehicle transmission and power train parts 

manufacturing.

327,377 473 692 63,004,961 2.04 1,285,596 0.00 0.05 

336370 ..... Motor vehicle metal stamping ...................................... 431,985 624 692 33,294,026 2.04 679,354 0.00 0.10 336399 ..... All other motor vehicle parts manufacturing ................ 583,803 843 693 31,304,202 2.04 638,752 0.00 0.11 336611 ..... Ship building and repair ............................................... 8,749,619 635 13,779 24,524,381 5.86 1,437,564 0.06 0.96 336612 ..... Boat building ................................................................ 5,479,624 1,129 4,854 9,474,540 5.86 555,376 0.05 0.87 336992 ..... Military armored vehicle, tank, and tank component 

manufacturing.

27,227 39 697 44,887,321 6.31 2,832,073 0.00 0.02 

337215 ..... Showcase, partition, shelving, and locker manufacturing. 233,720 334 701 4,943,560 4.54 224,593 0.01 0.31 339114 ..... Dental equipment and supplies manufacturing ........... 351,955 411 856 4,732,949 10.77 509,695 0.02 0.17 339116 ..... Dental laboratories ....................................................... 1,439,004 7,261 198 563,964 10.77 60,734 0.04 0.33 339911 ..... Jewelry (except costume) manufacturing .................... 1,560,353 1,777 878 3,685,009 5.80 213,566 0.02 0.41 339913 ..... Jewelers’ materials and lapidary work manufacturing 320,878 264 1,215 3,762,284 5.80 218,045 0.03 0.56 339914 ..... Costume jewelry and novelty manufacturing ............... 236,821 590 401 1,353,403 5.80 78,437 0.03 0.51 339950 ..... Sign manufacturing ...................................................... 294,919 496 594 1,872,356 5.80 108,513 0.03 0.55 423840 ..... Industrial supplies, wholesalers ................................... 177,299 383 463 1,913,371 3.44 65,736 0.02 0.70 482110 ..... Rail transportation ........................................................ 2,452,073 N/A N/A N/A N/A N/A N/A N/A 621210 ..... Dental offices ............................................................... 389,256 7,980 49 755,073 7.34 55,429 0.01 0.09 

Total ............................................................................. 146,726,595 56,121 2,571 .......................... .......................... .......................... .......................... ..........................

[a] Profit rates were calculated by ERG (2013) as the average of profit rates for 2000 through 2006, based on balance sheet data reported in the Internal Revenue Service’s Corporation Source Book (IRS, 2007). 

Source: U.S. Dept. of Labor, OSHA, Office of Regulatory Analysis, based on ERG (2013). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56372 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

b. Normal Year-to-Year Variations in 

Prices and Profit Rates 

The United States has a dynamic and 

constantly changing economy in which 

an annual percentage increase in 

industry revenues or prices of one 

percent or more are common. Examples 

of year-to-year changes in an industry 

that could cause such an increase in 

revenues or prices include increases in 

fuel, material, real estate, or other costs; 

tax increases; and shifts in demand. 

To demonstrate the normal year-toyear variation in prices for all the 

manufacturers in general industry and 

maritime affected by the proposed rule, 

OSHA developed in the PEA year-toyear producer price indices and year-toyear percentage changes in producer 

prices, by industry, for the years 1998– 

2009. For the combined affected 

manufacturing industries in general 

industry and maritime over the 12-year 

period, the average change in producer 

prices was 3.8 percent a year. For the 

three industries in general industry and 

maritime with the largest estimated 

potential annual cost impact as a 

percentage of revenue (of approximately 

0.35 percent, on average), the average 

annual changes in producer prices in 

these industries over the 12-year period 

averaged 3.5 percent. 

Based on these data, it is clear that the 

potential price impacts of the proposed 

rule in general industry and maritime 

are all well within normal year-to-year 

variations in prices in those industries. 

Thus, OSHA preliminarily concludes 

that the potential price impacts of the 

proposed would not threaten the 

economic viability of any industries in 

general industry and maritime. 

Changes in profit rates are also subject 

to the dynamics of the U.S. economy. A 

recession, a downturn in a particular 

industry, foreign competition, or the 

increased competitiveness of producers 

of close domestic substitutes are all 

easily capable of causing a decline in 

profit rates in an industry of well in 

excess of ten percent in one year or for 

several years in succession. 

To demonstrate the normal year-toyear variation in profit rates for all the 

manufacturers in general industry and 

maritime affected by the proposed rule, 

OSHA presented data in the PEA on 

year-to-year profit rates and year-to-year 

percentage changes in profit rates, by 

industry, for the years 2000–2006. For 

the combined affected manufacturing 

industries in general industry and 

maritime over the 7-year period, the 

average change in profit rates was 38.9 

percent a year. For the 7 industries in 

general industry and maritime with the 

largest estimated potential annual cost 

impacts as a percentage of profit— 

ranging from 4 percent to 9 percent—the 

average annual changes in profit rates in 

these industries over the 7-year period 

averaged 35 percent. 

Nevertheless, a longer-term reduction 

in profit rates in excess of 10 percent a 

year could be problematic for some 

affected industries and might 

conceivably, under sufficiently adverse 

circumstances, threaten an industry’s 

economic viability. In OSHA’s view, 

however, affected industries would 

generally be able to pass on most or all 

of the costs of the proposed rule in the 

form of higher prices rather than to bear 

the costs of the proposed rule in 

reduced profits. After all, it defies 

common sense to suggest that the 

demanded quantities of brick and 

structural clay, vitreous china, ceramic 

wall and floor tile, other structural clay 

products (such as clay sewer pipe), and 

the various other products 

manufactured by affected industries 

would significantly contract in response 

to a 0.4 percent (or lower) price increase 

for these products. It is of course 

possible that such price changes will 

result in some reduction in output, and 

the reduction in output might be met 

through the closure of a small 

percentage of the plants in the industry. 

However, the only realistic 

circumstance such that an entire 

industry would be significantly affected 

by small potential price increases would 

be the availability in the market of a 

very close or perfect substitute product 

not subject to OSHA regulation. The 

classic example, in theory, would be 

foreign competition. Below, OSHA 

examines the threat of foreign 

competition for affected U.S. 

establishments in general industry and 

maritime. 

c. International Trade Effects 

The magnitude and strength of foreign 

competition is a critical factor in 

determining the ability of firms in the 

U.S. to pass on (part or all of) the costs 

of the proposed rule. If firms are unable 

to do so, they would likely absorb the 

costs of the proposed rule out of profits, 

possibly resulting in the business failure 

of individual firms or even, if the cost 

impacts are sufficiently large and 

pervasive, causing significant 

dislocations within an affected industry. 

In the PEA, OSHA examined how 

likely such an outcome is. The analysis 

there included a review of trade theory 

and empirical evidence and the 

estimation of impacts. Throughout, the 

Agency drew on ERG (2007c), which 

was prepared specifically to help 

analyze the international trade impacts 

of OSHA’s proposed silica rule. A 

summary of the PEA results is presented 

below. 

ERG (2007c) focused its analysis on 

eight of the industries likely to be most 

affected by the proposed silica rule and 

for which import and export data were 

available. ERG combined econometric 

estimates of the elasticity of substitution 

between foreign and domestic products, 

Annual Survey of Manufactures data, 

and assumptions concerning the values 

for key parameters to estimate the effect 

of a range of hypothetical price 

increases on total domestic production. 

In particular, ERG estimated the 

domestic production that would be 

replaced by imported products and the 

decrease in exported products that 

would result from a 1 percent increase 

in prices—under the assumption that 

firms would attempt to pass on all of a 

1 percent increase in costs arising from 

the proposed rule. The sum of the 

increase in imports and decrease in 

exports represents the total loss to 

industry attributable to the rule. These 

projected losses are presented as a 

percentage of baseline domestic 

production to provide some context for 

evaluating the relative size of these 

impacts. 

The effect of a 1 percent increase in 

the price of a domestic product is 

derived from the baseline level of U.S. 

domestic production and the baseline 

level of imports. The baseline ratio of 

import values to domestic production 

for the eight affected industries ranges 

from 0.04 for iron foundries to 0.547 for 

ceramic wall and floor tile 

manufacturing—that is, baseline import 

values range from 4 percent to more 

than 50 percent of domestic production 

in these eight industries. ERG’s 

estimates of the percentage reduction in 

U.S. production for the eight affected 

industries due to increased domestic 

imports (arising from a 1 percent 

increase in the price of domestic 

products) range from 0.013 percent for 

iron foundries to 0.237 percent for cut 

stone and stone product manufacturing. 

ERG also estimated baseline ratio of 

U.S. exports to consumption in the rest 

of the world for the sample of eight 

affected industries. The ratios range 

from 0.001 for other concrete 

manufacturing to 0.035 percent for 

nonclay refractory manufacturing. The 

estimated percentage reductions in U.S. 

production due to reduced U.S. exports 

(arising from a 1 percent increase in the 

price of domestic products) range from 

0.014 percent for ceramic wall and floor 

tile manufacturing to 0.201 percent for 

nonclay refractory manufacturing. 

The total percentage change in U.S. 

production for the eight affected 

industries is the sum of the loss of 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56373 

increased imports and the loss of 

exports. The total percentage reduction 

in U.S. production arising from a 1 

percent increase in the price of domestic 

products range from a low of 0.085 

percent for other concrete product 

manufacturing to a high of 0.299 percent 

for porcelain electrical supply 

manufacturing. 

These estimates suggest that the 

proposed rule would have only modest 

international trade effects. It was 

previously hypothesized that if price 

increases resulted in a substantial loss 

of revenue to foreign competition, then 

the increased costs of the proposed rule 

would have to come out of profits. That 

possibility has been contradicted by the 

results reported in this section. The 

maximum loss to foreign competition in 

any affected industry due to a 1 percent 

price increase was estimated at 

approximately 0.3 percent of industry 

revenue. Because, as reported earlier in 

this section, the maximum cost impact 

of the proposed rule for any affected 

industry would be 0.39 percent of 

revenue, this means that the maximum 

loss to foreign competition in any 

affected industry as a result of the 

proposed rule would be 0.12 percent of 

industry revenue—which, even for the 

most affected industry, would hardly 

qualify as a substantial loss to foreign 

competition. This analysis cannot tell us 

whether the resulting change in 

revenues will lead to a small decline in 

the number of establishments in the 

industry or slightly less revenue for 

each establishment. However it can 

reasonably be concluded that revenue 

changes of this magnitude will not lead 

to the elimination of industries or 

significantly alter their competitive 

structure. 

Based on the Agency’s preceding 

analysis of economic impacts on 

revenues, profits, and international 

trade, OSHA preliminarily concludes 

that the annualized costs of the 

proposed rule are below the threshold 

level that could threaten the economic 

viability of any industry in general 

industry or maritime. OSHA further 

notes that while there would be 

additional costs (not attributable to the 

proposed rule) for some employers in 

general industry and maritime to come 

into compliance with the current silica 

standard, these costs would not affect 

the Agency’s preliminary determination 

of the economic feasibility of the 

proposed rule. 

d. Economic Feasibility Screening 

Analysis: Small and Very Small 

Businesses 

The preceding discussion focused on 

the economic viability of the affected 

industries in their entirety and found 

that the proposed standard did not 

threaten the survival of these industries. 

Now OSHA wishes to demonstrate that 

the competitive structure of these 

industries would not be significantly 

altered. 

To address this issue, OSHA 

examined the annualized costs per 

affected small entity and per very small 

entity for each affected industry in 

general industry and maritime. Again, 

OSHA used a minimum threshold level 

of annualized costs equal to one percent 

of annual revenues—and, secondarily, 

annualized costs equal to ten percent of 

annual profits—below which the 

Agency has concluded that the costs are 

unlikely to threaten the survival of 

small entities or very small entities or, 

consequently, to alter the competitive 

structure of the affected industries. 

As shown in Table VIII–12 and Table 

VIII–13, the annualized cost of the 

proposed rule is estimated to be $2,103 

for the average small entity in general 

industry and maritime and $616 for the 

average very small entity in general 

industry and maritime. These tables also 

show that there are no industries in 

general industry and maritime in which 

the annualized costs of the proposed 

rule for small entities or very small 

entities exceed one percent of annual 

revenues. NAICS 327111 (Vitreous 

china plumbing fixtures & bathroom 

accessories manufacturing) has the 

highest potential cost impact as a 

percentage of revenues, of 0.61 percent, 

for small entities, and NAICS 327112 

(Vitreous china, fine earthenware, & 

other pottery product manufacturing) 

has the highest potential cost impact as 

a percentage of revenues, of 0.75 

percent, for very small entities. Small 

entities in two industries in general 

industry and maritime—NAICS 327111 

and NAICS 327123 (Other structural 

clay product mfg.)—have annualized 

costs in excess of 10 percent of annual 

profits (13.91 percent and 10.63 percent, 

respectively). NAICS 327112 is the only 

industry in general industry and 

maritime in which the annualized costs 

of the proposed rule for very small 

entities exceed ten percent of annual 

profits (16.92 percent). 

In general, cost impacts for affected 

small entities or very small entities will 

tend to be somewhat higher, on average, 

than the cost impacts for the average 

business in those affected industries. 

That is to be expected. After all, smaller 

businesses typically suffer from 

diseconomies of scale in many aspects 

of their business, leading to less revenue 

per dollar of cost and higher unit costs. 

Small businesses are able to overcome 

these obstacles by providing specialized 

products and services, offering local 

service and better service, or otherwise 

creating a market niche for themselves. 

The higher cost impacts for smaller 

businesses estimated for this rule 

generally fall within the range observed 

in other OSHA regulations and, as 

verified by OSHA’s lookback reviews, 

have not been of such a magnitude to 

lead to their economic failure. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56374 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–12—SCREENING

ANALYSIS FOR

SMALL

ENTITIES IN

GENERAL INDUSTRY AND

MARITIME

AFFECTED BY OSHA’

S

PROPOSED

SILICA

STANDARD

NAICS Industry 

Total 

annualized 

costs 

Number of 

affected small 

entities 

Annualized cost 

per affected 

entity 

Revenues per 

entity 

Profit rate [a] 

(percent) 

Profits per 

entity 

Costs as a 

percentage 

of revenues 

Costs as a 

percentage 

of profits 

324121 ..... Asphalt paving mixture and block manufacturing ........ $140,305 431 $326 $10,428,583 7.50 $782,268 0.00 0.04 324122 ..... Asphalt shingle and roofing materials .......................... 872,614 106 8,232 14,067,491 7.50 1,055,229 0.06 0.78325510 ..... Paint and coating manufacturing ................................. 71,718 1,042 69 6,392,803 5.38 344,213 0.00 0.02 327111 ..... Vitreous china plumbing fixtures & bathroom accessories manufacturing. 231,845 25 9,274 1,509,677 4.41 66,651 0.61 13.91 327112 ..... Vitreous china, fine earthenware, & other pottery 

product manufacturing.

1,854,472 717 2,586 693,637 4.41 30,623 0.37 8.45 

327113 ..... Porcelain electrical supply mfg .................................... 1,004,480 97 10,355 4,574,464 4.41 201,959 0.23 5.13 327121 ..... Brick and structural clay mfg ........................................ 3,062,272 93 32,928 9,265,846 4.41 409,079 0.36 8.05 327122 ..... Ceramic wall and floor tile mfg .................................... 2,189,278 173 12,655 3,236,635 4.41 142,895 0.39 8.86 327123 ..... Other structural clay product mfg ................................. 510,811 42 12,162 2,592,114 4.41 114,440 0.47 10.63 327124 ..... Clay refractory manufacturing ...................................... 212,965 96 2,218 6,026,297 4.41 266,056 0.04 0.83327125 ..... Nonclay refractory manufacturing ................................ 211,512 68 3,110 7,346,739 4.41 324,352 0.04 0.96 327211 ..... Flat glass manufacturing .............................................. 275,155 56 4,913 64,950,007 3.42 2,221,884 0.01 0.22 327212 ..... Other pressed and blown glass and glassware manufacturing. 243,132 228 1,068 935,353 3.42 31,998 0.11 3.34 327213 ..... Glass container manufacturing .................................... 57,797 24 2,408 10,181,980 3.42 348,317 0.02 0.69 327320 ..... Ready-mixed concrete manufacturing ......................... 10,490,561 2,401 4,369 7,245,974 6.64 480,994 0.06 0.91 327331 ..... Concrete block and brick mfg ...................................... 2,862,910 567 5,049 6,318,185 6.64 419,407 0.08 1.20 327332 ..... Concrete pipe mfg ........................................................ 1,441,766 181 7,966 7,852,099 6.64 521,229 0.10 1.53 327390 ..... Other concrete product mfg ......................................... 8,826,516 1,876 4,705 3,521,965 6.64 233,791 0.13 2.01 327991 ..... Cut stone and stone product manufacturing ................ 8,028,431 1,874 4,284 1,730,741 5.49 95,001 0.25 4.51 327992 ..... Ground or treated mineral and earth manufacturing ... 2,108,649 132 15,975 6,288,188 5.49 345,160 0.25 4.63 327993 ..... Mineral wool manufacturing ......................................... 291,145 175 1,664 6,181,590 5.49 339,309 0.03 0.49 327999 ..... All other misc. nonmetallic mineral product mfg .......... 1,130,230 326 3,467 4,299,551 5.49 236,004 0.08 1.47 331111 ..... Iron and steel mills ....................................................... 424,557 523 812 82,895,665 4.49 3,723,664 0.00 0.02 331112 ..... Electrometallurgical ferroalloy product manufacturing 4,987 7 692 24,121,503 4.49 1,083,535 0.00 0.06 331210 ..... Iron and steel pipe and tube manufacturing from purchased steel. 84,537 94 896 40,090,061 4.49 1,800,841 0.00 0.05 331221 ..... Rolled steel shape manufacturing ................................ 42,672 54 787 31,848,937 4.49 1,430,651 0.00 0.05 331222 ..... Steel wire drawing ........................................................ 57,557 67 862 16,018,794 4.49 719,562 0.01 0.12 331314 ..... Secondary smelting and alloying of aluminum ............ 15,277 20 777 18,496,524 4.46 825,857 0.00 0.09 331423 ..... Secondary smelting, refining, and alloying of copper .. 4,206 6 722 20,561,614 4.42 907,800 0.00 0.08 331492 ..... Secondary smelting, refining, and alloying of nonferrous metal (except cu & al). 18,357 25 741 9,513,728 4.42 420,033 0.01 0.18 331511 ..... Iron foundries ............................................................... 5,312,382 408 13,021 5,865,357 4.11 241,290 0.22 5.40 331512 ..... Steel investment foundries ........................................... 1,705,373 101 16,885 8,489,826 4.11 349,255 0.20 4.83 331513 ..... Steel foundries (except investment) ............................. 2,521,998 192 13,135 11,977,647 4.11 492,738 0.11 2.67 331524 ..... Aluminum foundries (except die-casting) ..................... 4,316,135 412 10,476 4,039,244 4.11 166,167 0.26 6.30 331525 ..... Copper foundries (except die-casting) ......................... 1,596,288 246 6,489 2,847,376 4.11 117,136 0.23 5.54 331528 ..... Other nonferrous foundries (except die-casting) ......... 620,344 112 5,539 2,640,180 4.11 108,612 0.21 5.10 332111 ..... Iron and steel forging ................................................... 47,376 63 756 8,310,925 4.71 391,034 0.01 0.19 332112 ..... Nonferrous forging ........................................................ 13,056 17 760 21,892,338 4.71 1,030,048 0.00 0.07 332115 ..... Crown and closure manufacturing ............................... 5,080 7 732 6,697,995 4.71 315,145 0.01 0.23 332116 ..... Metal stamping ............................................................. 212,110 279 759 5,360,428 4.71 252,211 0.01 0.30 332117 ..... Powder metallurgy part manufacturing ........................ 17,537 23 762 6,328,522 4.71 297,761 0.01 0.26 332211 ..... Cutlery and flatware (except precious) manufacturing 10,419 14 738 2,852,835 5.22 149,022 0.03 0.50 332212 ..... Hand and edge tool manufacturing .............................. 87,599 113 772 3,399,782 5.22 177,592 0.02 0.43 332213 ..... Saw blade and handsaw manufacturing ...................... 9,221 12 752 5,385,465 5.22 281,317 0.01 0.27 332214 ..... Kitchen utensil, pot, and pan manufacturing ............... 10,475 13 798 10,355,293 5.22 540,923 0.01 0.15 332323 ..... Ornamental and architectural metal work .................... 28,608 42 673 2,069,492 4.70 97,346 0.03 0.69 332439 ..... Other metal container manufacturing ........................... 43,857 56 784 5,260,693 3.58 188,521 0.01 0.42 332510 ..... Hardware manufacturing .............................................. 78,538 104 756 4,442,699 5.22 232,070 0.02 0.33 332611 ..... Spring (heavy gauge) manufacturing ........................... 14,071 19 754 6,621,896 5.22 345,904 0.01 0.22 332612 ..... Spring (light gauge) manufacturing .............................. 36,826 44 834 4,500,760 5.22 235,103 0.02 0.35 332618 ..... Other fabricated wire product manufacturing ............... 113,603 148 765 3,440,489 5.22 179,719 0.02 0.43 332710 ..... Machine shops ............................................................. 1,032,483 1,399 738 1,464,380 5.80 84,907 0.05 0.87 332812 ..... Metal coating and allied services ................................. 2,492,357 2,301 1,083 2,904,851 4.85 141,018 0.04 0.77 332911 ..... Industrial valve manufacturing ..................................... 53,520 71 752 5,841,019 6.81 397,593 0.01 0.19 332912 ..... Fluid power valve and hose fitting manufacturing ....... 41,712 55 757 6,486,405 6.81 441,524 0.01 0.17 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56375 

332913 ..... Plumbing fixture fitting and trim manufacturing ........... 19,037 25 752 9,183,477 6.81 625,111 0.01 0.12 332919 ..... Other metal valve and pipe fitting manufacturing ........ 30,618 40 764 9,432,914 6.81 642,090 0.01 0.12 332991 ..... Ball and roller bearing manufacturing .......................... 13,624 18 741 5,892,239 6.81 401,079 0.01 0.18 332996 ..... Fabricated pipe and pipe fitting manufacturing ............ 74,633 99 754 4,377,576 6.81 297,978 0.02 0.25 332997 ..... Industrial pattern manufacturing ................................... 20,767 28 736 1,127,301 6.81 76,734 0.07 0.96 332998 ..... Enameled iron and metal sanitary ware manufacturing. 13,779 22 630 3,195,173 6.81 217,493 0.02 0.29 332999 ..... All other miscellaneous fabricated metal product manufacturing. 230,825 311 742 2,904,500 6.81 197,707 0.03 0.38 333319 ..... Other commercial and service industry machinery 

manufacturing.

123,816 165 750 4,960,861 4.86 241,023 0.02 0.31 

333411 ..... Air purification equipment manufacturing ..................... 27,021 36 748 4,449,669 4.55 202,591 0.02 0.37 333412 ..... Industrial and commercial fan and blower manufacturing. 27,149 34 791 7,928,953 4.55 361,000 0.01 0.22 333414 ..... Heating equipment (except warm air furnaces) manufacturing. 45,308 61 741 5,667,272 4.55 258,027 0.01 0.29 333511 ..... Industrial mold manufacturing ...................................... 143,216 193 743 2,121,298 5.29 112,203 0.04 0.66 333512 ..... Machine tool (metal cutting types) manufacturing ....... 44,845 60 746 4,136,962 5.29 218,818 0.02 0.34 333513 ..... Machine tool (metal forming types) manufacturing ...... 30,365 40 758 4,358,035 5.29 230,511 0.02 0.33 333514 ..... Special die and tool, die set, jig, and fixture manufacturing. 203,742 274 743 2,083,166 5.29 110,186 0.04 0.67 333515 ..... Cutting tool and machine tool accessory manufacturing. 104,313 140 746 2,082,357 5.29 110,143 0.04 0.68 333516 ..... Rolling mill machinery and equipment manufacturing 9,604 13 744 8,330,543 5.29 440,630 0.01 0.17 333518 ..... Other metalworking machinery manufacturing ............ 38,359 50 765 5,680,062 5.29 300,438 0.01 0.25 333612 ..... Speed changer, industrial high-speed drive, and gear 

manufacturing.

25,087 32 777 6,028,137 2.63 158,355 0.01 0.49 

333613 ..... Mechanical power transmission equipment manufacturing. 26,182 35 754 9,094,798 2.63 238,915 0.01 0.32 333911 ..... Pump and pumping equipment manufacturing ............ 41,360 54 762 6,220,799 4.58 284,686 0.01 0.27 333912 ..... Air and gas compressor manufacturing ....................... 23,948 32 758 6,290,845 4.58 287,891 0.01 0.26 333991 ..... Power-driven handtool manufacturing ......................... 9,867 13 732 3,816,319 4.58 174,648 0.02 0.42 333992 ..... Welding and soldering equipment manufacturing ........ 23,144 31 745 5,635,771 4.58 257,913 0.01 0.29 333993 ..... Packaging machinery manufacturing ........................... 54,872 74 742 4,240,165 4.58 194,045 0.02 0.38 333994 ..... Industrial process furnace and oven manufacturing .... 34,418 45 757 4,470,378 4.58 204,580 0.02 0.37 333995 ..... Fluid power cylinder and actuator manufacturing ........ 32,249 43 756 5,830,077 4.58 266,805 0.01 0.28 333996 ..... Fluid power pump and motor manufacturing ............... 15,258 20 772 4,401,836 4.58 201,444 0.02 0.38 333997 ..... Scale and balance (except laboratory) manufacturing 12,129 16 764 4,987,858 4.58 228,262 0.02 0.33 333999 ..... All other miscellaneous general purpose machinery 

manufacturing.

123,384 166 745 3,262,128 4.58 149,287 0.02 0.50 

334518 ..... Watch, clock, and part manufacturing ......................... 6,646 9 732 2,878,581 5.94 171,059 0.03 0.43 335211 ..... Electric housewares and household fans .................... 3,326 5 643 6,088,365 4.21 256,514 0.01 0.25 335221 ..... Household cooking appliance manufacturing .............. 6,521 10 649 10,460,359 4.21 440,715 0.01 0.15 335222 ..... Household refrigerator and home freezer manufacturing. 32,118 18 1,784 271,746,735 4.21 11,449,210 0.00 0.02 335224 ..... Household laundry equipment manufacturing ............. 30,521 17 1,795 299,665,426 4.21 12,625,478 0.00 0.01 335228 ..... Other major household appliance manufacturing ........ 1,917 3 671 8,269,046 4.21 348,391 0.01 0.19 336111 ..... Automobile manufacturing ............................................ 293,357 167 1,757 555,733,594 2.04 11,339,563 0.00 0.02 336112 ..... Light truck and utility vehicle manufacturing ................ 404,778 63 6,425 2,359,286,755 2.04 48,140,479 0.00 0.01 336120 ..... Heavy duty truck manufacturing .................................. 125,181 77 1,626 240,029,218 2.04 4,897,718 0.00 0.03 336211 ..... Motor vehicle body manufacturing ............................... 187,131 239 784 16,910,028 2.04 345,044 0.00 0.23 336212 ..... Truck trailer manufacturing .......................................... 54,137 72 748 9,018,164 2.04 184,013 0.01 0.41 336213 ..... Motor home manufacturing .......................................... 84,073 79 1,064 75,358,742 2.04 1,537,671 0.00 0.07 336311 ..... Carburetor, piston, piston ring, and valve manufacturing. 10,269 14 748 2,242,044 2.04 45,748 0.03 1.64 336312 ..... Gasoline engine and engine parts manufacturing ....... 65,767 94 703 4,245,230 2.04 86,623 0.02 0.81 336322 ..... Other motor vehicle electrical and electronic equipment manufacturing. 71,423 101 706 6,746,386 2.04 137,658 0.01 0.51 336330 ..... Motor vehicle steering and suspension components 

(except spring) manufacturing.

25,492 36 708 7,742,773 2.04 157,989 0.01 0.45 

336340 ..... Motor vehicle brake system manufacturing ................. 32,886 46 710 6,554,128 2.04 133,735 0.01 0.53 336350 ..... Motor vehicle transmission and power train parts 

manufacturing.

46,869 66 710 6,058,947 2.04 123,631 0.01 0.57 

336370 ..... Motor vehicle metal stamping ...................................... 159,156 201 792 11,477,248 2.04 234,190 0.01 0.34 336399 ..... All other motor vehicle parts manufacturing ................ 169,401 235 721 6,985,145 2.04 142,530 0.01 0.51 336611 ..... Ship building and repair ............................................... 8,749,619 575 15,217 27,083,446 5.86 1,587,570 0.06 0.96 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56376 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–12—SCREENING

ANALYSIS FOR

SMALL

ENTITIES IN

GENERAL INDUSTRY AND

MARITIME

AFFECTED BY OSHA’

S

PROPOSED

SILICA

STANDARD— 

Continued 

NAICS Industry 

Total 

annualized 

costs 

Number of 

affected small 

entities 

Annualized cost 

per affected 

entity 

Revenues per 

entity 

Profit rate [a] 

(percent) 

Profits per 

entity 

Costs as a 

percentage 

of revenues 

Costs as a 

percentage 

of profits 

336612 ..... Boat building ................................................................. 2,612,088 814 3,209 5,304,212 5.86 310,921 0.06 1.03 336992 ..... Military armored vehicle, tank, and tank component 

manufacturing.

27,227 32 845 54,437,815 6.31 3,434,642 0.00 0.02 

337215 ..... Showcase, partition, shelving, and locker manufacturing. 176,800 235 751 3,637,716 4.54 165,266 0.02 0.45 339114 ..... Dental equipment and supplies manufacturing ............ 261,393 292 895 2,619,222 10.77 282,066 0.03 0.32 339116 ..... Dental laboratories ....................................................... 1,397,271 7,011 199 532,828 10.77 57,381 0.04 0.35 339911 ..... Jewelry (except costume) manufacturing .................... 1,392,054 1,751 795 2,615,940 5.80 151,608 0.03 0.52 339913 ..... Jewelers’ materials and lapidary work manufacturing 257,285 258 997 2,775,717 5.80 160,868 0.04 0.62 339914 ..... Costume jewelry and novelty manufacturing ............... 242,158 588 412 971,681 5.80 56,314 0.04 0.73 339950 ..... Sign manufacturing ...................................................... 264,810 428 618 1,642,826 5.80 95,211 0.04 0.65 423840 ..... Industrial supplies, wholesalers ................................... 143,614 226 636 5,001,467 3.44 171,830 0.01 0.37 482110 ..... Rail transportation ........................................................ N/A N/A N/A N/A N/A N/A N/A N/A 621210 ..... Dental offices ................................................................ 370,174 7,423 50 663,948 7.34 48,739 0.01 0.10 

Total ............................................................................. 86,520,059 41,136 2,103 

[a] Profit rates were calculated by ERG, 2013, as the average of profit rates for 2000 through 2006, based on balance sheet data reported in the Internal Revenue Service’s Corporation Source Book (IRS, 2007). Source: U.S. Dept. of Labor, OSHA, Office of Regulatory Analysis, based on ERG (2013). 

TABLE VIII–13—SCREENING

ANALYSIS FOR

VERY

SMALL

ENTITIES (FEWER THAN 20 EMPLOYEES) IN

GENERAL INDUSTRY AND

MARITIME

AFFECTED BY OSHA’

S

PROPOSED

SILICA

STANDARD

NAICS Industry 

Total 

annualized 

costs 

Number of affected entities 

with <20 employees 

Annualized 

costs per affected entities Revenues per entity Profit rate [a] (percent) Profits per enti- ty Costs as a per- centage of rev- enues Costs as a per- centage of prof- its 

324121 ..... Asphalt paving mixture and block manufacturing ........ $27,770 260 $107 $4,335,678 7.50 $325,227 0.00 0.03 324122 ..... Asphalt shingle and roofing materials .......................... 85,253 57 1,496 4,013,780 7.50 301,081 0.04 0.50 325510 ..... Paint and coating manufacturing ................................. 18,910 324 58 1,871,296 5.38 100,758 0.00 0.06 327111 ..... Vitreous china plumbing fixtures & bathroom accessories manufacturing. 26,606 19 1,400 327,368 4.41 14,453 0.43 9.69 327112 ..... Vitreous china, fine earthenware, & other pottery 

product manufacturing.

747,902 645 1,160 155,258 4.41 6,855 0.75 16.92 

327113 ..... Porcelain electrical supply mfg .................................... 79,824 57 1,400 601,316 4.41 26,548 0.23 5.28 327121 ..... Brick and structural clay mfg ........................................ 76,696 31 2,474 715,098 4.41 31,571 0.35 7.84 327122 ..... Ceramic wall and floor tile mfg .................................... 382,871 136 2,815 807,291 4.41 35,641 0.35 7.90 327123 ..... Other structural clay product mfg ................................. 67,176 25 2,687 782,505 4.41 34,547 0.34 7.78 327124 ..... Clay refractory manufacturing ...................................... 29,861 55 543 1,521,469 4.41 67,172 0.04 0.81 327125 ..... Nonclay refractory manufacturing ................................ 34,061 40 852 1,506,151 4.41 66,495 0.06 1.28 327211 ..... Flat glass manufacturing .............................................. 4,450 4 1,075 905,562 3.42 30,978 0.12 3.47 327212 ..... Other pressed and blown glass and glassware manufacturing. 87,895 79 1,107 370,782 3.42 12,684 0.30 8.73 327213 ..... Glass container manufacturing .................................... 4,798 4 1,107 2,690,032 3.42 92,024 0.04 1.20 327320 ..... Ready-mixed concrete manufacturing ......................... 1,897,131 1,429 1,328 1,922,659 6.64 127,628 0.07 1.04 327331 ..... Concrete block and brick mfg ...................................... 544,975 339 1,608 1,995,833 6.64 132,485 0.08 1.21327332 ..... Concrete pipe mfg ........................................................ 116,670 67 1,741 2,375,117 6.64 157,662 0.07 1.10 327390 ..... Other concrete product mfg ......................................... 1,885,496 1,326 1,422 974,563 6.64 64,692 0.15 2.20 327991 ..... Cut stone and stone product manufacturing ................ 2,753,051 1,471 1,872 946,566 5.49 51,957 0.20 3.60 327992 ..... Ground or treated mineral and earth manufacturing ... 389,745 78 4,997 1,635,092 5.49 89,751 0.31 5.57 327993 ..... Mineral wool manufacturing ......................................... 48,575 46 1,061 1,398,274 5.49 76,752 0.08 1.38 327999 ..... All other misc. nonmetallic mineral product mfg .......... 311,859 235 1,327 1,457,181 5.49 79,985 0.09 1.66 331111 ..... Iron and steel mills ....................................................... 9,342 12 777 4,177,841 4.49 187,668 0.02 0.41 331112 ..... Electrometallurgical ferroalloy product manufacturing 0 0 N/A 1,202,610 4.49 54,021 N/A N/A 331210 ..... Iron and steel pipe and tube manufacturing from purchased steel. 1,706 2 774 2,113,379 4.49 94,933 0.04 0.82 331221 ..... Rolled steel shape manufacturing ................................ 1,612 2 774 2,108,498 4.49 94,713 0.04 0.82 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56377 

331222 ..... Steel wire drawing ........................................................ 2,939 4 774 835,444 4.49 37,528 0.09 2.06 331314 ..... Secondary smelting and alloying of aluminum ............ 1,254 2 774 2,039,338 4.46 91,055 0.04 0.85 331423 ..... Secondary smelting, refining, and alloying of copper .. 0 0 N/A 2,729,146 4.42 120,492 N/A N/A 331492 ..... Secondary smelting, refining, and alloying of nonferrous metal (except cu & al). 2,897 4 774 1,546,332 4.42 68,271 0.05 1.13 331511 ..... Iron foundries ............................................................... 330,543 201 1,644 1,031,210 4.11 42,422 0.16 3.88 331512 ..... Steel investment foundries ........................................... 47,902 27 1,774 1,831,394 4.11 75,340 0.10 2.35331513 ..... Steel foundries (except investment) ............................. 162,670 102 1,595 1,577,667 4.11 64,902 0.10 2.46 331524 ..... Aluminum foundries (except die-casting) ..................... 503,027 235 2,141 874,058 4.11 35,957 0.24 5.95 331525 ..... Copper foundries (except die-casting) ......................... 370,110 164 2,257 814,575 4.11 33,510 0.28 6.73 331528 ..... Other nonferrous foundries (except die-casting) ......... 162,043 77 2,104 837,457 4.11 34,451 0.25 6.11 332111 ..... Iron and steel forging ................................................... 4,089 5 774 1,175,666 4.71 55,316 0.07 1.40332112 ..... Nonferrous forging ........................................................ 784 1 774 1,431,874 4.71 67,371 0.05 1.15 332115 ..... Crown and closure manufacturing ............................... 992 1 774 1,715,882 4.71 80,733 0.05 0.96 332116 ..... Metal stamping ............................................................. 27,154 35 775 1,146,408 4.71 53,939 0.07 1.44 332117 ..... Powder metallurgy part manufacturing ........................ 2,072 3 774 1,580,975 4.71 74,386 0.05 1.04 332211 ..... Cutlery and flatware (except precious) manufacturing 2,217 3 774 391,981 5.22 20,476 0.20 3.78 332212 ..... Hand and edge tool manufacturing .............................. 19,535 25 774 770,858 5.22 40,267 0.10 1.92 332213 ..... Saw blade and handsaw manufacturing ...................... 2,296 3 774 975,698 5.22 50,967 0.08 1.52 332214 ..... Kitchen utensil, pot, and pan manufacturing ............... 0 0 N/A 826,410 5.22 43,169 N/A N/A 332323 ..... Ornamental and architectural metal work .................... 9,527 14 694 695,970 4.70 32,737 0.10 2.12 332439 ..... Other metal container manufacturing ........................... 5,279 7 788 1,027,511 3.58 36,822 0.08 2.14 332510 ..... Hardware manufacturing .............................................. 11,863 15 777 776,986 5.22 40,587 0.10 1.92 332611 ..... Spring (heavy gauge) manufacturing ........................... 1,927 2 786 1,774,584 5.22 92,698 0.04 0.85 332612 ..... Spring (light gauge) manufacturing .............................. 4,960 6 774 1,085,302 5.22 56,692 0.07 1.36 332618 ..... Other fabricated wire product manufacturing ............... 19,946 26 774 778,870 5.22 40,685 0.10 1.90 332710 ..... Machine shops ............................................................. 416,115 537 774 649,804 5.80 37,677 0.12 2.06 332812 ..... Metal coating and allied services ................................. 613,903 885 694 602,598 4.85 29,254 0.12 2.37 332911 ..... Industrial valve manufacturing ..................................... 5,886 8 774 1,294,943 6.81 88,146 0.06 0.88 332912 ..... Fluid power valve and hose fitting manufacturing ....... 4,491 6 774 1,350,501 6.81 91,927 0.06 0.84 332913 ..... Plumbing fixture fitting and trim manufacturing ........... 1,505 2 774 811,318 6.81 55,226 0.10 1.40 332919 ..... Other metal valve and pipe fitting manufacturing ........ 2,710 3 781 2,164,960 6.81 147,367 0.04 0.53 332991 ..... Ball and roller bearing manufacturing .......................... 1,132 1 774 1,808,246 6.81 123,086 0.04 0.63 332996 ..... Fabricated pipe and pipe fitting manufacturing ............ 12,453 16 774 1,237,265 6.81 84,220 0.06 0.92 332997 ..... Industrial pattern manufacturing ................................... 8,917 12 774 503,294 6.81 34,259 0.15 2.26 332998 ..... Enameled iron and metal sanitary ware manufacturing. 3,287 5 690 725,491 6.81 49,384 0.10 1.40 332999 ..... All other miscellaneous fabricated metal product manufacturing. 55,981 72 774 933,734 6.81 63,558 0.08 1.22 333319 ..... Other commercial and service industry machinery 

manufacturing.

19,776 26 774 1,127,993 4.86 54,803 0.07 1.41 

333411 ..... Air purification equipment manufacturing ..................... 4,745 6 774 1,152,661 4.55 52,480 0.07 1.47 333412 ..... Industrial and commercial fan and blower manufacturing. 1,675 2 774 1,454,305 4.55 66,214 0.05 1.17 333414 ..... Heating equipment (except warm air furnaces) manufacturing. 6,087 8 777 901,560 4.55 41,047 0.09 1.89 333511 ..... Industrial mold manufacturing ...................................... 43,738 56 774 716,506 5.29 37,898 0.11 2.04 333512 ..... Machine tool (metal cutting types) manufacturing ....... 8,756 11 776 911,891 5.29 48,233 0.09 1.61 333513 ..... Machine tool (metal forming types) manufacturing ...... 4,666 6 774 1,308,768 5.29 69,225 0.06 1.12 333514 ..... Special die and tool, die set, jig, and fixture manufacturing. 65,867 85 774 816,990 5.29 43,213 0.09 1.79 333515 ..... Cutting tool and machine tool accessory manufacturing. 31,406 41 775 771,162 5.29 40,789 0.10 1.90 333516 ..... Rolling mill machinery and equipment manufacturing 1,361 2 774 2,243,812 5.29 118,683 0.03 0.65 333518 ..... Other metalworking machinery manufacturing ............ 6,766 9 774 965,694 5.29 51,079 0.08 1.51 333612 ..... Speed changer, industrial high-speed drive, and gear 

manufacturing.

3,318 4 774 1,393,898 2.63 36,617 0.06 2.11 

333613 ..... Mechanical power transmission equipment manufacturing. 3,114 4 774 2,113,156 2.63 55,511 0.04 1.39 333911 ..... Pump and pumping equipment manufacturing ............ 7,209 9 774 1,343,868 4.58 61,500 0.06 1.26 333912 ..... Air and gas compressor manufacturing ....................... 4,228 5 774 1,644,664 4.58 75,266 0.05 1.03 333991 ..... Power-driven handtool manufacturing ......................... 2,212 3 774 2,158,268 4.58 98,770 0.04 0.78 333992 ..... Welding and soldering equipment manufacturing ........ 3,835 5 774 1,331,521 4.58 60,935 0.06 1.27 333993 ..... Packaging machinery manufacturing ........................... 9,742 13 774 809,474 4.58 37,044 0.10 2.09 333994 ..... Industrial process furnace and oven manufacturing .... 5,631 7 774 1,324,790 4.58 60,627 0.06 1.28 333995 ..... Fluid power cylinder and actuator manufacturing ........ 3,955 5 774 916,613 4.58 41,947 0.08 1.84 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56378 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–13—SCREENING

ANALYSIS FOR

VERY

SMALL

ENTITIES (FEWER THAN 20 EMPLOYEES) IN

GENERAL INDUSTRY AND

MARITIME

AFFECTED BY OSHA’

S

PROPOSED

SILICA

STANDARD—Continued 

NAICS Industry 

Total 

annualized 

costs 

Number of affected entities 

with <20 employees 

Annualized 

costs per affected entities Revenues per entity Profit rate [a] (percent) Profits per enti- ty Costs as a per- centage of rev- enues Costs as a per- centage of prof- its 

333996 ..... Fluid power pump and motor manufacturing ............... 2,670 3 774 1,417,549 4.58 64,872 0.05 1.19 333997 ..... Scale and balance (except laboratory) manufacturing 1,947 3 774 1,527,651 4.58 69,911 0.05 1.11 333999 ..... All other miscellaneous general purpose machinery 

manufacturing.

32,637 42 774 871,700 4.58 39,892 0.09 1.94 

334518 ..... Watch, clock, and part manufacturing ......................... 1,322 2 774 586,350 5.94 34,844 0.13 2.22 335211 ..... Electric housewares and household fans .................... 0 0 N/A 847,408 4.21 35,703 N/A N/A 335221 ..... Household cooking appliance manufacturing .............. 722 1 698 2,228,319 4.21 93,883 0.03 0.74 335222 ..... Household refrigerator and home freezer manufacturing. 0 0 N/A 4,917,513 4.21 207,184 N/A N/A 335224 ..... Household laundry equipment manufacturing ............. 0 0 N/A 1,767,776 4.21 74,480 N/A N/A 335228 ..... Other major household appliance manufacturing ........ 0 0 N/A 1,706,991 4.21 71,919 N/A N/A 336111 ..... Automobile manufacturing ............................................ 2,147 3 774 1,507,110 2.04 30,752 0.05 2.52 336112 ..... Light truck and utility vehicle manufacturing ................ 795 1 774 1,089,801 2.04 22,237 0.07 3.48 336120 ..... Heavy duty truck manufacturing .................................. 943 1 774 4,371,350 2.04 89,196 0.02 0.87 336211 ..... Motor vehicle body manufacturing ............................... 12,371 16 774 1,720,545 2.04 35,107 0.04 2.20 336212 ..... Truck trailer manufacturing .......................................... 5,147 7 774 2,706,375 2.04 55,223 0.03 1.40 336213 ..... Motor home manufacturing .......................................... 1,193 2 774 2,184,388 2.04 44,572 0.04 1.74 336311 ..... Carburetor, piston, piston ring, and valve manufacturing. 1,329 2 774 870,496 2.04 17,762 0.09 4.36 336312 ..... Gasoline engine and engine parts manufacturing ....... 11,683 15 774 867,703 2.04 17,705 0.09 4.37 336322 ..... Other motor vehicle electrical and electronic equipment manufacturing. 8,618 11 774 1,383,831 2.04 28,237 0.06 2.74 336330 ..... Motor vehicle steering and suspension components 

(except spring) manufacturing.

2,876 4 774 1,543,436 2.04 31,493 0.05 2.46 

336340 ..... Motor vehicle brake system manufacturing ................. 2,386 3 774 1,378,684 2.04 28,132 0.06 2.75 336350 ..... Motor vehicle transmission and power train parts 

manufacturing.

6,390 8 774 864,746 2.04 17,645 0.09 4.38 

336370 ..... Motor vehicle metal stamping ...................................... 5,759 7 778 1,519,875 2.04 31,013 0.05 2.51 336399 ..... All other motor vehicle parts manufacturing ................ 16,021 21 774 1,369,097 2.04 27,936 0.06 2.77 336611 ..... Ship building and repair ............................................... 212,021 65 3,252 770,896 5.86 45,188 0.42 7.20 336612 ..... Boat building ................................................................. 391,950 121 3,247 1,101,324 5.86 64,557 0.29 5.03 336992 ..... Military armored vehicle, tank, and tank component 

manufacturing.

0 0 N/A 1,145,870 6.31 72,296 N/A N/A 

337215 ..... Showcase, partition, shelving, and locker manufacturing. 28,216 36 774 866,964 4.54 39,387 0.09 1.96 339114 ..... Dental equipment and supplies manufacturing ............ 79,876 87 922 657,192 10.77 70,773 0.14 1.30 339116 ..... Dental laboratories ....................................................... 1,040,112 6,664 156 326,740 10.77 35,187 0.05 0.44 339911 ..... Jewelry (except costume) manufacturing .................... 533,353 1,532 348 673,857 5.80 39,054 0.05 0.89 339913 ..... Jewelers’ materials and lapidary work manufacturing 86,465 218 397 919,422 5.80 53,285 0.04 0.74 339914 ..... Costume jewelry and novelty manufacturing ............... 100,556 368 274 454,292 5.80 26,329 0.06 1.04 339950 ..... Sign manufacturing ...................................................... 89,586 140 639 521,518 5.80 30,225 0.12 2.12423840 ..... Industrial supplies, wholesalers ................................... 50,612 95 531 2,432,392 3.44 83,567 0.02 0.64 482110 ..... Rail transportation ........................................................ N/A N/A N/A N/A N/A N/A N/A N/A 621210 ..... Dental offices ................................................................ 320,986 6,506 49 562,983 7.34 41,328 0.01 0.12 

Total ............................................................................. 15,745,425 25,544 616 

aProfit rates were calculated by ERG, 2013, as the average of profit rates for 2000 through 2006, based on balance sheet data reported in the Internal Revenue Service’s Corporation Source Book (IRS, 2007). 

Source: U.S. Dept. of Labor, OSHA, Office of Regulatory Analysis, based on ERG (2013). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56379 

As a point of clarification, OSHA 

would like to draw attention to 

industries with captive foundries. There 

are three industries with captive 

foundries whose annualized costs for 

very small entities approach five 

percent of annual profits: NAICS 336311 

(Carburetor, piston ring, and valve 

manufacturing); NAICS 336312 

(Gasoline engine and engine parts 

manufacturing); and NAICS 336350 

(Motor vehicle transmission and power 

train parts manufacturing). For very 

small entities in all three of these 

industries, the annualized costs as a 

percentage of annual profits are 

approximately 4.4 percent. OSHA 

believes, however, that very small 

entities in industries with captive 

foundries are unlikely to actually have 

captive foundries and that the captive 

foundries allocated to very small 

entities in fact belong in larger entities. 

This would have the result that the costs 

as percentage of profits for these larger 

entities would be lower than the 4.4 

percent reported above. Instead, OSHA 

assumed that the affected employees 

would be distributed among entities of 

different size according to each entity 

size class’s share of total employment. 

In other words, if 15 percent of 

employees in an industry worked in 

very small entities (those with fewer 

than 20 employees), then OSHA 

assumed that 15 percent of affected 

employees in the industry would work 

in very small entities. However, in 

reality, OSHA anticipates that in 

industries with captive foundries, none 

of the entities with fewer than 20 

employees have captive foundries or, if 

they do, that the impacts are much 

smaller than estimated here. OSHA 

invites comment about whether and to 

what extent very small entities have 

captive foundries (in industries with 

captive foundries). 

Regardless of whether the cost 

estimates have been inflated for very 

small entities in the three industries 

with captive foundries listed above, 

there are two reasons why OSHA is 

confident that the competitive structure 

of these industries would not be 

threatened by adverse competitive 

conditions for very small entities. First, 

as shown in Appendix VI–B of the PEA, 

very small entities in NAICS 336311, 

NAICS 336312, and NAICS 336350 

account for 3 percent, 2 percent, and 3 

percent, respectively, of the total 

number of establishments in the 

industry. Although it is possible that 

some of these very small entities could 

exit the industry in response to the 

proposed rule, courts interpreting the 

OSH Act have historically taken the 

view that losing at most 3 percent of the 

establishments in an industry would 

alter the competitive structure of that 

industry. Second, very small entities in 

industries with captive foundries, when 

confronted with higher foundry costs as 

a result of the proposed rule, have the 

option of dropping foundry activities, 

purchasing foundry products and 

services from businesses directly in the 

foundry industry, and focusing on the 

main goods and services produced in 

the industry. This, after all, is precisely 

what the rest of the establishments in 

these industries do. 

e. Regulatory Flexibility Screening 

Analysis 

To determine if the Assistant 

Secretary of Labor for OSHA can certify 

that the proposed silica rule will not 

have a significant economic impact on 

a substantial number of small entities, 

the Agency has developed screening 

tests to consider minimum threshold 

effects of the proposed rule on small 

entities. The minimum threshold effects 

for this purpose are annualized costs 

equal to one percent of annual revenues 

and annualized costs equal to five 

percent of annual profits applied to each 

affected industry. OSHA has applied 

these screening tests both to small 

entities and to very small entities. For 

purposes of certification, the threshold 

level cannot be exceeded for affected 

small entities or very small entities in 

any affected industry. 

Table VIII–12 and Table VIII–13 show 

that, in general industry and maritime, 

the annualized costs of the proposed 

rule do not exceed one percent of 

annual revenues for small entities or for 

very small entities in any industry. 

These tables also show that the 

annualized costs of the proposed rule 

exceed five percent of annual profits for 

small entities in 10 industries and for 

very small entities in 13 industries. 

OSHA is therefore unable to certify that 

the proposed rule will not have a 

significant economic impact on a 

substantial number of small entities in 

general industry and maritime and must 

prepare an Initial Regulatory Flexibility 

Analysis (IRFA). The IRFA is presented 

in Section VIII.I of this preamble. 

3. Impacts in Construction 

a. Economic Feasibility Screening 

Analysis: All Establishments 

To determine whether the proposed 

rule’s projected costs of compliance 

would threaten the economic viability 

of affected construction industries, 

OSHA used the same data sources and 

methodological approach that were used 

earlier in this chapter for general 

industry and maritime. OSHA first 

compared, for each affected 

construction industry, annualized 

compliance costs to annual revenues 

and profits per (average) affected 

establishment. The results for all 

affected establishments in all affected 

construction industries are presented in 

Table VIII–14, using annualized costs 

per establishment for the proposed 50 

mg/m3 PEL. The annualized cost of the 

proposed rule for the average 

establishment in construction, 

encompassing all construction 

industries, is estimated at $1,022 in 

2009 dollars. It is clear from Table VIII– 

14 that the estimates of the annualized 

costs per affected establishment in the 

10 construction industries vary widely. 

These estimates range from $2,598 for 

NAICS 237300 (Highway, street, and 

bridge construction) and $2,200 for 

NAICS 237100 (Utility system 

construction) to $241 for NAICS 238200 

(Building finishing contractors) and 

$171 for NAICS 237200 (Land 

subdivision). 

Table VIII–14 shows that in no 

construction industry do the annualized 

costs of the proposed rule exceed one 

percent of annual revenues or ten 

percent of annual profits. NAICS 238100 

(Foundation, structure, and building 

exterior contractors) has both the 

highest cost impact as a percentage of 

revenues, of 0.13 percent, and the 

highest cost impact as a percentage of 

profits, of 2.97 percent. Based on these 

results, even if the costs of the proposed 

rule were 50 percent higher than OSHA 

has estimated, the highest cost impact as 

a percentage of revenues in any affected 

construction industry would be less 

than 0.2 percent. Furthermore, the costs 

of the proposed rule would have to be 

more than 650 percent higher than 

OSHA has estimated for the cost impact 

as a percentage of revenues to equal 1 

percent in any affected construction 

industry. For all affected establishments 

in construction, the estimated 

annualized cost of the proposed rule is, 

on average, equal to 0.05 percent of 

annual revenue and 1.0 percent of 

annual profit. 

Therefore, even though the 

annualized costs of the proposed rule 

incurred by the construction industry as 

a whole are almost four times the 

combined annualized costs incurred by 

general industry and maritime, OSHA 

preliminarily concludes, based on its 

screening analysis, that the annualized 

costs as a percentage of annual revenues 

and as a percentage of annual profits are 

below the threshold level that could 

threaten the economic viability of any of 

the construction industries. OSHA 

further notes that while there would be 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56380 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

additional costs (not attributable to the 

proposed rule) for some employers in 

construction industries to come into 

compliance with the current silica 

standard, these costs would not affect 

the Agency’s preliminary determination 

of the economic feasibility of the 

proposed rule. 

Below, OSHA provides additional 

information to further support the 

Agency’s conclusion that the proposed 

rule would not threaten the economic 

viability of any construction industry. 

TABLE VIII–14—SCREENING ANALYSIS FOR ESTABLISHMENTS IN CONSTRUCTION AFFECTED BY OSHA’S PROPOSED SILICA

STANDARD

NAICS Industry 

Total 

annualized 

costs 

Affected establishments 

Annualized 

costs per 

affected 

establishment 

Revenues 

per establishment 

Profit rate a

(percent) 

Profits per 

establishment 

Costs as a 

percentage of 

revenues 

Costs as a 

percentage of 

profits 

236100 ..... Residential Building 

Construction.

$23,288,881 55,338 $421 $2,002,532 4.87 $97,456 0.02 0.43 

236200 ..... Nonresidential Building 

Construction.

39,664,913 44,702 887 7,457,045 4.87 362,908 0.01 0.24 

237100 ..... Utility System Construction.46,718,162 21,232 2,200 4,912,884 5.36 263,227 0.04 0.84 

237200 ..... Land Subdivision ........ 1,110,789 6,511 171 2,084,334 11.04 230,214 0.01 0.07 

237300 ..... Highway, Street, and 

Bridge Construction.

30,807,861 11,860 2,598 8,663,019 5.36 464,156 0.03 0.56 

237900 ..... Other Heavy and Civil 

Engineering Construction.

7,164,210 5,561 1,288 3,719,070 5.36 199,264 0.03 0.65 

238100 ..... Foundation, Structure, 

and Building Exterior 

Contractors.

215,907,211 117,456 1,838 1,425,510 4.34 61,832 0.13 2.97 

238200 ..... Building Equipment 

Contractors.

4,902,138 20,358 241 1,559,425 4.34 67,640 0.02 0.36 

238300 ..... Building Finishing Contractors.50,259,239 120,012 419 892,888 4.34 38,729 0.05 1.08 

238900 ..... Other Specialty Trade 

Contractors.

68,003,978 74,446 913 1,202,048 4.48 53,826 0.08 1.70 

999000 ..... State and local governments d.

23,338,234 N/A N/A N/A N/A N/A N/A N/A 

Total ............................ 511,165,616 477,476 1,022 ...................... ...................... ...................... ...................... ......................

aProfit rates were calculated by ERG, 2013, as the average of profit rates for 2000 through 2006, based on balance sheet data reported in the Internal Revenue 

Service’s Corporation Source Book (IRS, 2007). 

Source: U.S. Dept. of Labor, OSHA, Office of Regulatory Analysis, based on ERG (2013). 

b. Normal Year-to-Year Variations in 

Profit Rates 

As previously noted, the United 

States has a dynamic and constantly 

changing economy in which large yearto-year changes in industry profit rates 

are commonplace. A recession, a 

downturn in a particular industry, 

foreign competition, or the increased 

competitiveness of producers of close 

domestic substitutes are all easily 

capable of causing a decline in profit 

rates in an industry of well in excess of 

ten percent in one year or for several 

years in succession. 

To demonstrate the normal year-toyear variation in profit rates for all the 

manufacturers in construction affected 

by the proposed rule, OSHA presented 

data in the PEA on year-to-year profit 

rates and year-to-year percentage 

changes in profit rates, by industry, for 

the years 2000—2006. For the combined 

affected manufacturing industries in 

general industry and maritime over the 

7-year period, the average change in 

profit rates was 15.4 percent a year. 

What these data indicate is that, even 

if, theoretically, the annualized costs of 

the proposed rule for the most 

significantly affected construction 

industries were completely absorbed in 

reduced annual profits, the magnitude 

of reduced annual profit rates are well 

within normal year-to-year variations in 

profit rates in those industries and do 

not threaten their economic viability. Of 

course, a permanent loss of profits 

would present a greater problem than a 

temporary loss, but it is unlikely that all 

costs of the proposed rule would be 

absorbed in lost profits. Given that, as 

discussed in Chapter VI of the PEA, the 

overall price elasticity of demand for the 

outputs of the construction industry is 

fairly low and that almost all of the 

costs estimated in Chapter V of the PEA 

are variable costs, there is a reasonable 

chance that most firms will see small 

declines in output rather than that any 

but the most extremely marginal firms 

would close. 

Considering the costs of the proposed 

rule relative to the size of construction 

activity in the United States, OSHA 

preliminarily concludes that the price 

and profit impacts of the proposed rule 

on construction industries would, in 

practice, be quite limited. Based on ERG 

(2007a), on an annual basis, the cost of 

the proposed rule would be equal to 

approximately 2 percent of the value of 

affected, silica-generating construction 

activity, and silica-generating 

construction activity accounts for 

approximately 4.8 percent of all 

construction spending in the U.S. Thus, 

the annualized cost of the proposed rule 

would be equal to approximately 0.1 

percent of the value of annual 

construction activity in the U.S. On top 

of that, construction activity in the U.S. 

is not subject to any meaningful foreign 

competition, and any foreign firms 

performing construction activities in the 

United States would be subject to OSHA 

regulations. 

c. Impacts by Type of Construction 

Demand 

The demand for construction services 

originates in three independent sectors: 

residential building construction, 

nonresidential building construction, 

and nonbuilding construction. 

Residential Building Construction: 

Residential housing demand is derived 

from the household demand for housing 

services. These services are provided by 

the stock of single and multi-unit 

residential housing units. Residential 

housing construction represents changes 

to the housing stock and includes 

construction of new units and 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56381 

modifications, renovations, and repairs 

to existing units. A number of studies 

have examined the price sensitivity of 

the demand for housing services. 

Depending on the data source and 

estimation methodologies, these studies 

have estimated the demand for housing 

services at price elasticity values 

ranging from –0.40 to –1.0, with the 

smaller (in absolute value) less elastic 

values estimated for short-run periods. 

In the long run, it is reasonable to 

expect the demand for the stock of 

housing to reflect similar levels of price 

sensitivity. Since housing investments 

include changes in the existing stock 

(renovations, depreciation, etc.) as well 

as new construction, it is likely that the 

price elasticity of demand for new 

residential construction will be lower 

than that for residential construction as 

a whole. 

OSHA judges that many of the silicagenerating construction activities 

affected by the proposed rule are not 

widely used in single-family 

construction. This assessment is 

consistent with the cost estimates that 

show relatively low impacts for 

residential building contractors. Multifamily residential construction might 

have more substantial impacts, but, 

based on census data, this type of 

construction represents a relatively 

small share of net investment in 

residential buildings. 

Nonresidential Building Construction: 

Nonresidential building construction 

consists of industrial, commercial, and 

other nonresidential structures. As such, 

construction demand is derived from 

the demand for the output of the 

industries that use the buildings. For 

example, the demand for commercial 

office space is derived from the demand 

for the output produced by the users of 

the office space. The price elasticity of 

demand for this construction category 

will depend, among other things, on the 

price elasticity of demand for the final 

products produced, the importance of 

the costs of construction in the total cost 

of the final product, and the elasticity of 

substitution of other inputs that could 

substitute for nonresidential building 

construction. ERG (2007c) found no 

studies that attempted to quantify these 

relationships. But given the costs of the 

proposed rule relative to the size of 

construction spending in the United 

States, the resultant price or revenue 

effects are likely to be so small as to be 

barely detectable. 

Nonbuilding Construction: 

Nonbuilding construction includes 

roads, bridges, and other infrastructure 

projects. Utility construction (power 

lines, sewers, water mains, etc.) and a 

variety of other construction types are 

also included. A large share of this 

construction (63.8 percent) is publicly 

financed (ERG, 2007a). For this reason, 

a large percentage of the decisions 

regarding the appropriate level of such 

investments is not made in a private 

market setting. The relationship 

between the costs and price of such 

investments and the level of demand 

might depend more on political 

considerations than the factors that 

determine the demand for privately 

produced goods and services. 

While a number of studies have 

examined the factors that determine the 

demand for publicly financed 

construction projects, these studies have 

focused on the ability to finance such 

projects (e.g., tax receipts) and sociodemographic factors (e.g., population 

growth) to the exclusion of cost or price 

factors. In the absence of budgetary 

constraints, OSHA believes, therefore, 

that the price elasticity of demand for 

public investment is probably quite low. 

On the other hand, budget-imposed 

limits might constrain public 

construction spending. If the dollar 

value of public investments were fixed, 

a price elasticity of demand of 1 (in 

absolute terms) would be implied. Any 

percentage increase in construction 

costs would be offset with an equal 

percentage reduction in investment 

(measured in physical units), keeping 

public construction expenditures 

constant. 

Public utility construction comprises 

the remainder of nonbuilding 

construction. This type of construction 

is subject to the same derived-demand 

considerations discussed for 

nonresidential building construction, 

and for the same reasons, OSHA expects 

the price and profit impacts to be quite 

small. 

d. Economic Feasibility Screening 

Analysis: Small and Very Small 

Businesses 

The preceding discussion focused on 

the economic viability of the affected 

construction industries in their entirety 

and found that the proposed standard 

did not threaten the survival of these 

construction industries. Now OSHA 

wishes to demonstrate that the 

competitive structure of these industries 

would not be significantly altered. 

To address this issue, OSHA 

examined the annualized costs per 

affected small and very small entity for 

each affected construction industry. 

Table VIII–15 and Table VIII–16 show 

that in no construction industries do the 

annualized costs of the proposed rule 

exceed one percent of annual revenues 

or ten percent of annual profits either 

for small entities or for very small 

entities. Therefore, OSHA preliminarily 

concludes, based on its screening 

analysis, that the annualized costs as a 

percentage of annual revenues and as a 

percentage of annual profits are below 

the threshold level that could threaten 

the competitive structure of any of the 

construction industries. 

TABLE VIII–15—SCREENING ANALYSIS FOR SMALL ENTITIES IN CONSTRUCTION AFFECTED BY OSHA’S PROPOSED SILICA

STANDARD

NAICS Industry 

Total 

annualized 

costs 

Affected 

small entities 

Annualized 

costs per 

affected 

entities 

Revenues 

per entities 

Profit rate a

(percent) 

Profits per 

entities 

Costs as a 

percentage of revenues 

Costs as a 

percentage of 

profits 

236100 ..... Residential Building 

Construction.

$18,527,934 44,212 $419 $1,303,262 4.87 $67,420 0.03 0.62 

236200 ..... Nonresidential Building 

Construction.

24,443,185 42,536 575 4,117,755 4.87 200,396 0.01 0.29 

237100 ..... Utility System Construction.30,733,201 20,069 1,531 3,248,053 5.36 174,027 0.05 0.88 

237200 ..... Land Subdivision ........ 546,331 3,036 180 1,215,688 11.04 134,272 0.01 0.13 

237300 ..... Highway, Street, and 

Bridge Construction.

13,756,992 10,350 1,329 3,851,971 5.36 206,385 0.03 0.64 

237900 ..... Other Heavy and Civil 

Engineering Construction.

5,427,484 5,260 1,032 2,585,858 5.36 138,548 0.04 0.74 

238100 ..... Foundation, Structure, 

and Building Exterior 

Contractors.

152,160,159 115,345 1,319 991,258 4.34 42,996 0.13 3.07 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56382 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–15—SCREENING ANALYSIS FOR SMALL ENTITIES IN CONSTRUCTION AFFECTED BY OSHA’S PROPOSED SILICA

STANDARD—Continued 

NAICS Industry 

Total 

annualized 

costs 

Affected 

small entities 

Annualized 

costs per 

affected 

entities 

Revenues 

per entities 

Profit rate a

(percent) 

Profits per 

entities 

Costs as a 

percentage of revenues 

Costs as a 

percentage of 

profits 

238200 ..... Building Equipment 

Contractors.

3,399,252 13,933 244 1,092,405 4.34 47,383 0.02 0.51 

238300 ..... Building Finishing Contractors.36,777,673 87,362 421 737,930 4.34 32,008 0.06 1.32 

238900 ..... Other Specialty Trade 

Contractors.

53,432,213 73,291 729 1,006,640 4.48 45,076 0.07 1.62 

999000 ..... State and local governments [d].2,995,955 13,482 222 N/A N/A N/A N/A N/A 

Total ............................ 342,200,381 428,876 798 ...................... ...................... ...................... ...................... ......................

aProfit rates were calculated by ERG, 2013, as the average of profit rates for 2000 through 2006, based on balance sheet data reported in the Internal Revenue 

Service’s Corporation Source Book (IRS, 2007). 

Source: U.S. Dept. of Labor, OSHA, Office of Regulatory Analysis, based on ERG (2013). 

TABLE VIII–16—SCREENING ANALYSIS FOR VERY SMALL ENTITIES (FEWER THAN 20 EMPLOYEES) IN CONSTRUCTION

AFFECTED BY OSHA’S PROPOSED SILICA STANDARD

NAICS Industry 

Total 

annualized 

costs 

Affected entities with <20 

employees 

Annualized 

costs per affected entities Revenues 

per entities 

Profit rate [a] 

(percent) 

Profits per 

entities 

Costs as a 

percentage of 

revenues 

Costs as a 

percentage of 

profits 

236100 ..... Residential Building 

Construction.

$13,837,293 32,042 $432 $922,275 4.87 $44,884 0.05 0.96 

236200 ..... Nonresidential Building 

Construction.

10,777,269 35,746 301 1,902,892 4.87 92,607 0.02 0.33 

237100 ..... Utility System Construction.8,578,771 16,113 532 991,776 5.36 53,138 0.05 1.00 

237200 ..... Land Subdivision ........ 546,331 3,036 180 1,215,688 11.04 134,272 0.01 0.13 

237300 ..... Highway, Street, and 

Bridge Construction.

4,518,038 8,080 559 1,649,324 5.36 88,369 0.03 0.63 

237900 ..... Other Heavy and Civil 

Engineering Construction.

1,650,007 4,436 372 834,051 5.36 44,688 0.04 0.83 

238100 ..... Foundation, Structure, 

and Building Exterior 

Contractors.

81,822,550 105,227 778 596,296 4.34 25,864 0.13 3.01 

238200 ..... Building Equipment 

Contractors.

1,839,588 7,283 253 579,724 4.34 25,146 0.04 1.00 

238300 ..... Building Finishing Contractors.21,884,973 50,749 431 429,154 4.34 18,615 0.10 2.32 

238900 ..... Other Specialty Trade 

Contractors.

30,936,078 68,075 454 600,658 4.48 26,897 0.08 1.69 

999000 ..... State and local governments [d].N/A N/A N/A N/A N/A N/A N/A N/A 

Total ............................ 176,390,899 330,786 533 ...................... ...................... ...................... ...................... ......................

aProfit rates were calculated by ERG, 2013, as the average of profit rates for 2000 through 2006, based on balance sheet data reported in the Internal Revenue 

Service’s Corporation Source Book (IRS, 2007). 

Source: U.S. Dept. of Labor, OSHA, Office of Regulatory Analysis, based on ERG (2013). 

e. Differential Impacts on Small Entities 

and Very Small Entities 

Below, OSHA provides some 

additional information about differential 

compliance costs for small and very 

small entities that might influence the 

magnitude of differential impacts for 

these smaller businesses. 

The distribution of impacts by size of 

business is affected by the 

characteristics of the compliance 

measures. For silica controls in 

construction, the dust control measures 

consist primarily of equipment 

modifications and additions made to 

individual tools, rather than large, 

discrete investments, such as might be 

applied in a manufacturing setting. As 

a result, compliance advantages for large 

firms through economies of scale are 

limited. It is possible that some large 

construction firms might derive 

purchasing power by buying dust 

control measures in bulk. Given the 

simplicity of many control measures, 

however, such as the use of wet 

methods on machines already 

manufactured to accommodate them, 

such differential purchasing power 

appears to be of limited consequence. 

The greater capital resources of large 

firms will give them some advantage in 

making the relatively large investments 

for some control measures. For example, 

cab enclosures on heavy construction 

equipment or foam-based dust control 

systems on rock crushers might be 

particularly expensive for some small 

entities with an unusual number of 

heavy equipment pieces. Nevertheless, 

where differential investment 

capabilities might exist, small 

construction firms might also have the 

capability to achieve compliance with 

lower-cost measures, such as by 

modifying work practices. In the case of 

rock crushing, for example, simple 

water spray systems can be arranged 

without large-scale investments in the 

best commercially available systems. 

In the program area, large firms might 

have a slight advantage in the delivery 

of training or in arranging for health 

screenings. Given the likelihood that 

small firms can, under most 

circumstances, call upon independent 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56383 

20 Inforum has over 40 years experience designing 

and using macroeconomic models of the United 

States (and other countries). 

21LIFT stands for Long-Term Interindustry 

Forecasting Tool. This model combines a dynamic 

input-output core for 97 productive sectors with a 

full macroeconomic model with more than 800 

macroeconomic variables. LIFT employs a 

‘‘bottoms-up’’ regression approach to 

macroeconomic modeling (so that aggregate 

investment, employment, and exports, for example, 

are the sum of investment and employment by 

industry and exports by commodity). Unlike some 

simpler forecasting models, price effects are 

embedded in the model and the results are timedependent (that is, they are not static or steadystate, but present year-by-year estimates of impacts 

consistent with economic conditions at the time). 

22OSHA worked with Inforum to disaggregate 

compliance costs into categories that mapped into 

specific LIFT production sectors. Inforum also 

established a mapping between OSHA’s NAICSbased industries and the LIFT production sectors. 

OSHA’s compliance cost estimates were based on 

production and employment levels in affected 

industries in 2006 (although the costs were then 

inflated to 2009 dollars). Therefore, Inforum 

benchmarked compliance cost estimates in future 

years to production and employment conditions in 

2006 (that is, compliance costs in a future year were 

proportionately adjusted to production and 

employment changes from 2006 to that future year). 

See Inforum (2011) for a discussion of these and 

other transformations of OSHA’s cost estimates to 

conform to the specifications of the LIFT model. 

23Because OSHA’s analysis of the hydraulic 

fracturing industry for the proposed silica rule was 

not conducted until after the draft PEA had been 

completed, OSHA’s estimates of the compliance 

costs for this industry were not included in 

Inforum’s analysis of the rule’s employment and 

other macroeconomic impacts on the U.S. economy. 

It should be noted that, according to the Agency’s 

estimates, compliance costs for the hydraulic 

fracturing industry represent only about 4 percent 

of the total compliance costs for all affected 

industries. 

24A ‘‘job-year’’ is the term of art used to reflect 

the fact that an additional person is employed for 

a year, not that a new job has necessarily been 

permanently created. 

training specialists at competitive 

prices, and the widespread availability 

of medical services for health 

screenings, the advantage for large firms 

is, again, expected to be fairly modest. 

f. Regulatory Flexibility Screening 

Analysis 

To determine if the Assistant 

Secretary of Labor for OSHA can certify 

that the proposed silica rule will not 

have a significant economic impact on 

a substantial number of small entities, 

the Agency has developed screening 

tests to consider minimum threshold 

effects of the proposed rule on small 

entities. The minimum threshold effects 

for this purpose are annualized costs 

equal to one percent of annual revenues 

and annualized costs equal to five 

percent of annual profits applied to each 

affected industry. OSHA has applied 

these screening tests both to small 

entities and to very small entities. For 

purposes of certification, the threshold 

levels cannot be exceeded for affected 

small or very small entities in any 

affected industry. 

Table VIII–15 and Table VIII–16 show 

that in no construction industries do the 

annualized costs of the proposed rule 

exceed one percent of annual revenues 

or five percent of annual profits either 

for small entities or for very small 

entities. However, as previously noted 

in this section, OSHA is unable to 

certify that the proposed rule will not 

have a significant economic impact on 

a substantial number of small entities in 

general industry and maritime and must 

prepare an Initial Regulatory Flexibility 

Analysis (IRFA). The IRFA is presented 

in Section VIII.I of this preamble. 

4. Employment Impacts on the U.S. 

Economy 

In October 2011, OSHA directed 

Inforum—a not-for-profit Maryland 

corporation (based at the University of 

Maryland)—to run its macroeconomic 

model to estimate the employment 

impacts of the costs of the proposed 

silica rule.20 The specific model of the 

U.S. economy that Inforum used—called 

the LIFT model—is particularly suitable 

for this work because it combines the 

industry detail of a pure input-output 

model (which shows, in matrix form, 

how the output of each industry serves 

as inputs in other industries) with 

macroeconomic modeling of demand, 

investment, and other macroeconomic 

parameters.21 The Inforum model can 

thus both trace changes in particular 

industries through their effect on other 

industries and also examine the effects 

of these changes on aggregate demand, 

imports, exports, and investment, and in 

turn determine net changes to GDP, 

employment, prices, etc. 

In order to estimate the possible 

macroeconomic impacts of the proposed 

rule, Inforum had to run its model 

twice: once to establish a baseline and 

then again with changes in industry 

expenditures to reflect the year-by-year 

costs of the proposed silica rule as 

estimated by OSHA in its Preliminary 

Economic Analysis (PEA).22 The 

difference in employment, GDP, etc. 

between the two runs of the model 

revealed the estimated economic 

impacts of the proposed rule.23

OSHA selected 2014 as the starting 

year for running the Inforum model 

under the assumption that that would 

be the earliest that a final silica rule 

could take effect. Inforum ran the model 

through the year 2023 and reported its 

annual and cumulative results for the 

ten-year period 2014–2023. The most 

important Inforum result is that the 

proposed silica rule cumulatively 

generates an additional 8,625 job-years 

over the period 2014–2023, or an 

additional 862.5 job-years annually, on 

average, over the period (Inforum, 

2011).24

For a fuller discussion of the 

employment and other macroeconomic 

impacts of the silica rule, see Inforum 

(2011) and Chapter VI of the PEA for the 

proposed rule. 

G. Benefits and Net Benefits 

In this section, OSHA presents a 

summary of the estimated benefits, net 

benefits, and incremental benefits of the 

proposed silica rule. This section also 

contains a sensitivity analysis to show 

how robust the estimates of net benefits 

are to changes in various cost and 

benefit parameters. A full explanation of 

the derivation of the estimates presented 

here is provided in Chapter VII of the 

PEA for the proposed rule. OSHA 

invites comments on any aspect of its 

estimation of the benefits and net 

benefits of the proposed rule. 

1. Estimation of the Number of SilicaRelated Diseases Avoided 

OSHA estimated the benefits 

associated with the proposed PEL of 50 

mg/m3 and, for economic analysis 

purposes, with an alternative PEL of 100 

mg/m3 for respirable crystalline silica by 

applying the dose-response relationship 

developed in the Agency’s quantitative 

risk assessment (QRA)—summarized in 

Section VI of this preamble—to 

exposures at or below the current PELs. 

OSHA determined exposures at or 

below the current PELs by first 

developing an exposure profile 

(presented in Chapter IV of the PEA) for 

industries with workers exposed to 

respirable crystalline silica, using OSHA 

inspection and site-visit data, and then 

applying this exposure profile to the 

total current worker population. The 

industry-by-industry exposure profile 

was previously presented in Section 

VIII.C of this preamble. 

By applying the dose-response 

relationship to estimates of exposures at 

or below the current PELs across 

industries, it is possible to project the 

number of cases of the following 

diseases expected to occur in the worker 

population given exposures at or below 

the current PELs (the ‘‘baseline’’): 

• Fatal cases of lung cancer, 

• fatal cases of non-malignant 

respiratory disease (including silicosis), 

• fatal cases of end-stage renal 

disease, and 

• cases of silicosis morbidity. 

In addition, it is possible to project 

the number of these cases that would be 

avoided under alternative, lower PELs. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56384 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

25Based on available data, the Agency estimated 

the weighted average for the relevant exposure 

groups to match up with the quantitative risk 

assessment. For the 50–100 mg/m3 exposure range, 

the Agency estimated an average exposure of 62.5 

mg/m3. For the 100–250 mg/m3 range, the Agency 

estimated an average exposure of 125 mg/m3. 

26Section (6)(b)(5) of the OSH Act states: ‘‘The 

Secretary, in promulgating standards dealing with 

toxic materials or harmful physical agents under 

this subsection, shall set the standard which most 

adequately assures, to the extent feasible, on the 

basis of the best available evidence, that no 

employee will suffer material impairment of health 

or functional capacity even if such employee has 

regular exposure to the hazard dealt with by such 

standard for the period of his working life.’’ Given 

that it is necessary for OSHA to reach a 

determination of significant risk over a working life, 

it is a logical extension to estimate what this 

translates into in terms of estimated benefits for the 

affected population over the same period. 

As a simplified example, suppose that 

the risk per worker of a given health 

endpoint is 2 in 1,000 at 100 mg/m3 and 

1 in 1,000 at 50 mg/m3 and that there are 

100,000 workers currently exposed at 

100 mg/m3. In this example, the 

proposed PEL would lower exposures to 

50 mg/m3, thereby cutting the risk in half 

and lowering the number of expected 

cases in the future from 200 to 100. 

The estimated benefits for the 

proposed silica rule represent the 

additional benefits derived from 

employers achieving full compliance 

with the proposed PEL relative to the 

current PELs. They do not include 

benefits associated with current 

compliance that has already been 

achieved with regard to the new 

requirements or benefits obtained from 

future compliance with existing silica 

requirements, to the extent that some 

employers may currently not be fully 

complying with applicable regulatory 

requirements. 

The technological feasibility analysis, 

described earlier in this section of the 

preamble, demonstrated the 

effectiveness of controls in meeting or 

exceeding the proposed OSHA PEL. For 

purposes of estimating the benefit of 

reducing the PEL, OSHA has made some 

simplifying assumptions. On the one 

hand, given the lack of background 

information on respirator use related to 

existing exposure data, OSHA used 

existing personal exposure 

measurement information, unadjusted 

for potential respirator use.25 On the 

other hand, OSHA assumed that 

compliance with the existing and 

proposed rule would result in 

reductions in exposure levels to exactly 

the existing standard and proposed PEL, 

respectively. However, in many cases, 

indivisibilities in the application of 

respirators, as well as certain types of 

engineering controls, may cause 

employers to reduce exposures to some 

point below the existing standard or the 

proposed PEL. This is particularly true 

in the construction sector for employers 

who opt to follow Table 1, which 

specifies particular controls. 

In order to examine the effect of 

simply changing the PEL, OSHA 

compared the number of various kinds 

of cases that would occur if a worker 

were exposed for an entire working life 

to PELs of 50 mg/m3 or 100 mg/m3 to the 

number of cases that would occur at 

levels of exposure at or below the 

current PELs. The number of avoided 

cases over a hypothetical working life of 

exposure for the current population at a 

lower PEL is then equal to the difference 

between the number of cases at levels of 

exposure at or below the current PEL for 

that population minus the number of 

cases at the lower PEL. This approach 

represents a steady-state comparison 

based on what would hypothetically 

happen to workers who received a 

specific average level of occupational 

exposure to silica during an entire 

working life. (In order to incorporate the 

element of timing to assess the 

economic value of the health benefits, 

OSHA presents a modified approach 

later in this section.) 

Based on OSHA’s application of the 

Steenland et al. (2001) log-linear and the 

Attfield and Costello (2004) models, 

Table VIII–17 shows the estimated 

number of avoided fatal lung cancers for 

PELs of 50 mg/m3 and 100 mg/m3. At the 

proposed PEL of 50 mg/m3, an estimated 

2,404 to 12,173 lung cancers would be 

prevented over the lifetime of the 

current worker population, with a 

midpoint estimate of 7,289 fatal cancers 

prevented. This is the equivalent of 

between 53 and 271 cases avoided 

annually, with a midpoint estimate of 

162 cases avoided annually, given a 45- 

year working life of exposure. 

Following Park (2002), as discussed in 

summary of the Agency’s QRA in 

Section VI of this preamble, OSHA also 

estimates that the proposed PEL of 50 

mg/m3 would prevent an estimated 

16,878 fatalities over a lifetime from 

non-malignant respiratory diseases 

arising from silica exposure. This is 

equivalent to 375 fatal cases prevented 

annually. Some of these fatalities would 

be classified as silicosis, but most would 

be classified as other pneumoconioses 

and chronic obstructive pulmonary 

disease (COPD), which includes chronic 

bronchitis and emphysema. 

As also discussed in the summary of 

the Agency’s QRA in Section VI of this 

preamble, OSHA finds that workers 

with large exposures to silica are at 

elevated risk of end-stage renal disease 

(ESRD). Based on Steenland, Attfield, 

and Mannetje (2002), OSHA estimates 

that the proposed PEL of 50 mg/m3

would prevent 6,774 cases of end-stage 

renal disease over a working life of 

exposure, or about 151 cases annually. 

Combining the three major fatal 

health endpoints—for lung cancer, nonmalignant respiratory diseases, and endstage renal disease—OSHA estimates 

that the proposed PEL would prevent 

between 26,055 and 35,825 premature 

fatalities over a lifetime, with a 

midpoint estimate of 30,940 fatalities 

prevented. This is the equivalent of 

between 579 and 796 premature 

fatalities avoided annually, with a 

midpoint estimate of 688 premature 

fatalities avoided annually, given a 45- 

year working life of exposure. 

In addition, the rule would prevent a 

large number of cases of silicosis 

morbidity. Based on Rosenman et al. 

(2003), the Agency estimates that 

between 2,700 and 5,475 new cases of 

silicosis, at an ILO X-ray rating of 1/0 or 

higher, occur annually at the present 

PELs as a result of silica exposure at 

establishments within OSHA’s 

jurisdiction. Based on the studies 

summarized in OSHA’s QRA, OSHA 

expects that the proposed rule will 

eliminate the large majority of these 

cases. 

The Agency has not included the 

elimination of the less severe silicosis 

cases in its estimates of the monetized 

benefits and net benefits of the proposed 

rule. Instead, OSHA separately 

estimated the number of silicosis cases 

reaching the more severe levels of 2/1 

and above. Based on a study by 

Buchannan et al. (2003) of a cohort of 

coal miners (as discussed in the 

Agency’s QRA), OSHA estimates that 

the proposed PEL of 50 mg/m3 would 

prevent 71,307 cases of moderate-tosevere silicosis (registering 2/1 or more, 

using the ILO method for assessing 

severity) over a working life, or about 

1,585 cases of moderate-to-severe 

silicosis prevented annually. 

Note that the Agency based its 

estimates of reductions in the number of 

silica-related diseases over a working 

life of constant exposure for workers 

who are employed in a respirable 

crystalline silica-exposed occupation for 

their entire working lives, from ages 20 

to 65. While the Agency is legally 

obligated to examine the effect of 

exposures from a working lifetime of 

exposure,26 in an alternative analysis 

purely for informational purposes, the 

Agency examined, in Chapter VII of the 

PEA, the effect of assuming that workers 

are exposed for only 25 working years, 

as opposed to the 45 years assumed in 

the main analysis. While all workers are 

assumed to have less cumulative 

exposure under the 25-years-ofmstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56385 

27Technically, this analysis assumes that workers 

receive 25 years worth of silica exposure, but that 

they receive it over 45 working years, as is assumed 

by the risk models in the QRA. It also accounts for 

the turnover implied by 25, as opposed to 45, years 

of work. However, it is possible that an alternate 

analysis, which accounts for the larger number of 

post-exposure worker-years implied by workers 

departing their jobs before the end of their working 

lifetime, might find larger health effects for workers 

receiving 25 years worth of silica exposure. 

exposure assumption, the effective 

exposed population over time is 

proportionately increased. Estimated 

prevented cases of end-stage renal 

disease and silicosis morbidity are 

lower in the 25-year model, whereas 

cases of fatal non-malignant lung 

disease are higher. In the case of lung 

cancer, the effect varies by model, with 

a lower high-end estimate (Attfield & 

Costello, 2004) and a higher low-end 

estimate (Steenland et. al., 2001 loglinear model). Overall, however, the 45- 

year-working-life assumption yields 

larger estimates of the number of cases 

of avoided fatalities and illnesses than 

does the 25-years-of-exposure 

assumption. For example, the midpoint 

estimates of the number of avoided 

fatalities and illnesses under the 

proposed PEL of 50 mg/m3 would 

decline from 688 and 1,585, 

respectively, under the 45-year-workinglife assumption to 683 and 642, 

respectively, under the 25-year-workinglife assumption. Note the effect, in this 

case, of going from a 45-year-workinglife assumption to a 25-year-working-life 

assumption would be a 1 percent 

reduction in the number of avoided 

fatalities and a 59 percent reduction in 

the number of avoided illnesses. The 

divergence reflects differences in the 

mathematical structure of the risk 

assessment models that are the basis for 

these estimates.27

OSHA believes that 25 years of 

worker exposure to respirable 

crystalline silica may be a reasonable 

alternative estimate for informational 

purposes. However, to accommodate the 

possibility that average worker exposure 

to silica over a working life may be 

shorter, at least in certain industries (see 

the following paragraph), the Agency 

also examined the effect of assuming 

only 13 years of exposure for the 

average worker. The results were 

broadly similar to the 25 years of 

exposure—annual fatalities prevented 

were higher (788), but illnesses 

prevented lower (399), with the lower 

average cumulative exposure being 

offset to a substantial degree by a larger 

exposed population. The same effect is 

seen if one assumes only 6.6 years of 

cumulative exposure to silica for the 

average worker: estimated fatalities rise 

to 832 cases annually, with 385 cases of 

silicosis morbidity. In short, the 

aggregate estimated benefits of the rule 

appear to be relatively insensitive to 

implicit assumptions of average 

occupational tenure. Nonetheless, the 

Agency is confident that the typical 

affected worker sustains an extended 

period of exposure to silica. 

Even in the construction industry, 

which has an extremely high rate of job 

turnover, the mean job tenure with one’s 

current employer is 6.6 years (BLS, 

2010a), and the median age of 

construction workers in the U.S. is 41.6 

years (BLS, 2010b). OSHA is unaware of 

any data on job tenure within an 

industry, but the Agency would expect 

job tenure in the construction industry 

would be at least twice the job tenure 

with one’s current employer. 

Furthermore, many workers may return 

to the construction industry after 

unemployment or work in another 

industry. Of course, job tenure is longer 

in the other industries affected by the 

proposed rule. 

The proposed rule also contains 

specific provisions for diagnosing latent 

tuberculosis (TB) in the silica-exposed 

population and thereby reducing the 

risk of TB being spread to the 

population at large. The Agency 

currently lacks good methods for 

quantifying these benefits. Nor has the 

Agency attempted to assess benefits 

directly stemming from enhanced 

medical surveillance in terms of 

reducing the severity of symptoms from 

the illnesses that do result from present 

or future exposure to silica. However, 

the Agency welcomes comment on the 

likely magnitude of these currently nonquantified health benefits arising from 

the proposed rule and on methods for 

better measuring these effects. 

OSHA’s risk estimates are based on 

application of exposure-response 

models derived from several individual 

epidemiological studies as well as the 

pooled cohort studies of Steenland et al. 

(2001) and Mannetje et al. (2002). OSHA 

recognizes that there is uncertainty 

around any of the point estimates of risk 

derived from any single study. In its 

preliminary risk assessment 

(summarized in Section VI of this 

preamble), OSHA has made efforts to 

characterize some of the more important 

sources of uncertainty to the extent that 

available data permit. This specifically 

includes characterizing statistical 

uncertainty by reporting the confidence 

intervals around each of the risk 

estimates; by quantitatively evaluating 

the impact of uncertainties in 

underlying exposure data used in the 

cohort studies; and by exploring the use 

of alternative exposure-response model 

forms. OSHA believes that these efforts 

reflect much, but not necessarily all, of 

the uncertainties associated with the 

approaches taken by investigators in 

their respective risk analyses. However, 

OSHA believes that characterizing the 

risks and benefits as a range of estimates 

derived from the full set of available 

studies, rather than relying on any 

single study as the basis for its 

estimates, better reflects the 

uncertainties in the estimates and more 

fairly captures the range of risks likely 

to exist across a wide range of industries 

and exposure situations. 

Another source of uncertainty 

involves the degree to which OSHA’s 

risk estimates reflect the risk of disease 

among workers with widely varying 

exposure patterns. Some workers are 

exposed to fairly high concentrations of 

crystalline silica only intermittently, 

while others experience more regular 

and constant exposure. Risk models 

employed in the quantitative assessment 

are based on a cumulative exposure 

metric, which is the product of average 

daily silica concentration and duration 

of worker exposure for a specific job. 

Consequently, these models predict the 

same risk for a given cumulative 

exposure regardless of the pattern of 

exposure, reflecting a worker’s longterm average exposure without regard to 

intermittencies or other variances in 

exposure, and are therefore generally 

applicable to all workers who are 

exposed to silica in the various 

industries. Section VI of this preamble 

provides evidence supporting the use of 

cumulative exposure as the preferred 

dose metric. Although the Agency 

believes that the results of its risk 

assessment are broadly relevant to all 

occupational exposure situations 

involving crystalline silica, OSHA 

acknowledges that differences exist in 

the relative toxicity of crystalline silica 

particles present in different work 

settings due to factors such as the 

presence of mineral or metal impurities 

on quartz particle surfaces, whether the 

particles have been freshly fractured or 

are aged, and size distribution of 

particles. However, in its preliminary 

risk assessment, OSHA preliminarily 

concludes that the estimates from the 

studies and analyses relied upon are 

fairly representative of a wide range of 

workplaces reflecting differences in 

silica polymorphism, surface properties, 

and impurities. 

Thus, OSHA has a high degree of 

confidence in the risk estimates 

associated with exposure to the current 

and proposed PELs. OSHA 

acknowledges there is greater 

uncertainty in the risk estimates for the 

proposed action level of 0.025 mg/m3

than exists at the current (0.1 mg/m3) 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56386 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

and proposed (0.05 mg/m3) PELs, 

particularly given some evidence of a 

threshold for silicosis between the 

proposed PEL and action level. Given 

the Agency’s findings that controlling 

exposures below the proposed PEL 

would not be technologically feasible 

for employers, OSHA believes that a 

precise estimate of the risk for 

exposures below the proposed action 

level is not necessary to further inform 

the Agency’s regulatory action. OSHA 

requests comment on remaining sources 

of uncertainties in its risk and benefits 

estimates that have not been specifically 

characterized by OSHA in its analysis. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2


EP12SE13.008</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table VIII-17 

Estimated Number of Avoided Fatal & Nonfatal Illnesses Resulting from a Reduction in Crystalline Silica Exposure of At-Risk Workers over a 45-Year Workin

IJg/m3 and Alternative PEL of 100 IJg/m3 

Total Number of Avoided Cases Annual Number o

50 100 50 

Total Construction GI& Total Construction GI& Total Construction GI& 

Maritime Maritime Maritime 

Lung Cancers 

High 12,173 9,537 2,636 6,563 6,277 286 271 212 59 

Midpoint 7,289 5,852 1,437 3,719 3,573 146 162 130 32 Low 2,404 2,166 238 875 869 6 53 48 5 

Silicosis & Other Non-Malignant Respiratory 16,878 13,944 2,934 8,490 8,403 87 375 310 65 

Diseases End Stage Renal Disease 6,774 5,722 1,052 2,684 2,655 29 151 127 23 

Total Number of Fatal Illnesses Prevented 

High 35,825 29,203 6,622 17,737 17,335 402 796 649 147 

Midpoint 30,940 25,517 5,423 14,893 14,631 262 688 567 121 

Low 26,055 21,831 4,224 12,049 11,927 122 579 485 94 

Total Number of Silicosis Morbidity Cases 71,307 48,617 22,689 42,881 41,375 1,506 1,585 1,080 504 

Prevented' 

*Assessed at 2/1 or higher X-ray, following ILO criteria 

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis. Office of Regulatory Analysis 
56388 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

28See, for example, Thaler and Rosen (1976), pp. 

265–266. In addition, see Sunstein (2004), p. 433. 

‘‘This point demonstrates a general and badly 

neglected problem for WTP as it is currently used: 

agencies consider people’s WTP to eliminate 

statistical risks, without taking account of the fact 

that others—especially family members and close 

friends—would also be willing to pay something to 

eliminate those risks.’’ 

29On the former assumption, see the discussion 

in Chapter II of the PEA on imperfect information. 

On the latter, see, for example, the discussion of 

wage compensation for risk for union versus 

nonunion workers in Dorman and Hagstrom (1998). 

30For example, if workers are willing to pay $50 

each for a 1/100,000 reduction in the probability of 

dying on the job, then the imputed value of an 

avoided fatality would be $50 divided by 1/100,000, 

or $5,000,000. Another way to consider this result 

would be to assume that 100,000 workers made this 

trade-off. On average, one life would be saved at a 

cost of $5,000,000. 

31An alternative approach to valuing an avoided 

fatality is to monetize, for each year that a life is 

extended, an estimate from the economics literature 

of the value of that statistical life-year (VSLY). See, 

for instance, Aldy and Viscusi (2007) for discussion 

of VSLY theory and FDA (2003), pp. 41488–9, for 

an application of VSLY in rulemaking. OSHA has 

not investigated this approach, but welcomes 

comment on the issue. 

2. Estimating the Stream of Benefits 

Over Time 

Risk assessments in the occupational 

environment are generally designed to 

estimate the risk of an occupationally 

related illness over the course of an 

individual worker’s lifetime. As 

previously discussed, the current 

occupational exposure profile for a 

particular substance for the current 

cohort of workers can be matched up 

against the expected profile after the 

proposed standard takes effect, creating 

a ‘‘steady state’’ estimate of benefits. 

However, in order to annualize the 

benefits for the period of time after the 

silica rule takes effect, it is necessary to 

create a timeline of benefits for an entire 

active workforce over that period. 

In order to characterize the magnitude 

of benefits before the steady state is 

reached, OSHA created a linear phasein model to reflect the potential timing 

of benefits. Specifically, OSHA 

estimated that, for all non-cancer cases, 

while the number of cases would 

gradually decline as a result of the 

proposed rule, they would not reach the 

steady-state level until 45 years had 

passed. The reduction in cases 

estimated to occur in any given year in 

the future was estimated to be equal to 

the steady-state reduction (the number 

of cases in the baseline minus the 

number of cases in the new steady state) 

times the ratio of the number of years 

since the standard was implemented 

and a working life of 45 years. 

Expressed mathematically: 

Nt=(C—S) × (t/45), 

where Nt is the number of nonmalignant silica-related diseases 

avoided in year t; C is the current 

annual number of non-malignant silicarelated diseases; S is the steady-state 

annual number of non-malignant silicarelated diseases; and t represents the 

number of years after the proposed 

standard takes effect, with t≤45. 

In the case of lung cancer, the 

function representing the decline in the 

number of cases as a result of the 

proposed rule is similar, but there 

would be a 15-year lag before any 

reduction in cancer cases would be 

achieved. Expressed mathematically, for 

lung cancer: 

Lt=(Cm—Sm) x ((t-15)/45)), 

where 15 ≤ t ≤ 60 and Lt is the number 

of lung cancer cases avoided in year t 

as a result of the proposed rule; Cm is 

the current annual number of silicarelated lung cancers; and Sm is the 

steady-state annual number of silicarelated lung cancers. 

A more complete discussion of the 

functioning and results of this model is 

presented in Chapter VII of the PEA. 

This model was extended to 60 years 

for all the health effects previously 

discussed in order to incorporate the 15- 

year lag, in the case of lung cancer, and 

a 45-year working life. As a practical 

matter, however, there is no overriding 

reason for stopping the benefits analysis 

at 60 years. An internal analysis by 

OSHA indicated that, both in terms of 

cases prevented, and even with regard 

to monetized benefits, particularly when 

lower discount rates are used, the 

estimated benefits of the standard are 

noticeably larger on an annualized basis 

if the analysis extends further into the 

future. The Agency welcomes comment 

on the merit of extending the benefits 

analysis beyond the 60 years analyzed 

in the PEA. 

In order to compare costs to benefits, 

OSHA assumes that economic 

conditions remain constant and that 

annualized costs—and the underlying 

costs—will repeat for the entire 60-year 

time horizon used for the benefits 

analysis (as discussed in Chapter V of 

the PEA). OSHA welcomes comments 

on the assumption for both the benefit 

and cost analysis that economic 

conditions remain constant for sixty 

years. OSHA is particularly interested in 

what assumptions and time horizon 

should be used instead and why. 

3. Monetizing the Benefits 

To estimate the monetary value of the 

reductions in the number of silicarelated fatalities, OSHA relied, as OMB 

recommends, on estimates developed 

from the willingness of affected 

individuals to pay to avoid a marginal 

increase in the risk of fatality. While a 

willingness-to-pay (WTP) approach 

clearly has theoretical merit, it should 

be noted that an individual’s 

willingness to pay to reduce the risk of 

fatality would tend to underestimate the 

total willingness to pay, which would 

include the willingness of others— 

particularly the immediate family—to 

pay to reduce that individual’s risk of 

fatality.28

For estimates using the willingnessto-pay concept, OSHA relied on existing 

studies of the imputed value of fatalities 

avoided based on the theory of 

compensating wage differentials in the 

labor market. These studies rely on 

certain critical assumptions for their 

accuracy, particularly that workers 

understand the risks to which they are 

exposed and that workers have 

legitimate choices between high- and 

low-risk jobs. These assumptions are far 

from obviously met in actual labor 

markets.29 A number of academic 

studies, as summarized in Viscusi & 

Aldy (2003), have shown a correlation 

between higher job risk and higher 

wages, suggesting that employees 

demand monetary compensation in 

return for a greater risk of injury or 

fatality. The estimated trade-off between 

lower wages and marginal reductions in 

fatal occupational risk—that is, workers’ 

willingness to pay for marginal 

reductions in such risk—yields an 

imputed value of an avoided fatality: the 

willingness-to-pay amount for a 

reduction in risk divided by the 

reduction in risk.30 OSHA has used this 

approach in many recent proposed and 

final rules. Although this approach has 

been found to yield results that are less 

than statistically robust (see, for 

example, Hintermann, Alberini and 

Markandya, 2010), OSHA views these 

estimates as the best available, and will 

use them for its basic estimates. OSHA 

welcomes comments on the use of 

willingness-to-pay measures and 

estimates based on compensating wage 

differentials. 

Viscusi & Aldy (2003) conducted a 

meta-analysis of studies in the 

economics literature that use a 

willingness-to-pay methodology to 

estimate the imputed value of lifesaving programs and found that each 

fatality avoided was valued at 

approximately $7 million in 2000 

dollars. This $7 million base number in 

2000 dollars yields an estimate of $8.7 

million in 2009 dollars for each fatality 

avoided.31

In addition to the benefits that are 

based on the implicit value of fatalities 

avoided, workers also place an implicit 

value on occupational injuries or 

illnesses avoided, which reflect their 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56389 

32There are several benchmarks for valuation of 

health impairment due to silica exposure, using a 

variety of techniques, which provide a number of 

mid-range estimates between OSHA’s high and low 

estimates. For a fuller discussion of these estimates, 

see Chapter VII of the PEA. 

33As previously indicated, these valuations 

include all the various estimated health endpoints. 

In the case of mortality this includes lung cancer, 

non-malignant respiratory disease and end-stage 

renal disease. The Agency highlighted lung cancers 

in this discussion due to the model uncertainty. In 

calculating the monetized benefits, the Agency is 

typically referring to the midpoint of the high and 

low ends of potential valuation—in this case, the 

undiscounted midpoint of $3.2 billion and $10.9 

billion.. 

willingness to pay to avoid monetary 

costs (for medical expenses and lost 

wages) and quality-of-life losses as a 

result of occupational illness. Silicosis, 

lung cancer, and renal disease can 

adversely affect individuals for years or 

even decades in non-fatal cases, or 

before ultimately proving fatal. Because 

measures of the benefits of avoiding 

these illnesses are rare and difficult to 

find, OSHA has included a range based 

on a variety of estimation methods. 

Consistent with Buchannan et al. 

(2003), OSHA estimated the total 

number of moderate to severe silicosis 

cases prevented by the proposed rule, as 

measured by 2/1 or more severe X-rays 

(based on the ILO rating system). 

However, while radiological evidence of 

moderate to severe silicosis is evidence 

of significant material impairment of 

health, placing a precise monetary value 

on this condition is difficult, in part 

because the severity of symptoms may 

vary significantly among individuals. 

For that reason, for this preliminary 

analysis, the Agency employed a broad 

range of valuation, which should 

encompass the range of severity these 

individuals may encounter. Using the 

willingness-to-pay approach, discussed 

in the context of the imputed value of 

fatalities avoided, OSHA has estimated 

a range in valuations (updated and 

reported in 2009 dollars) that runs from 

approximately $62,000 per case—which 

reflects estimates developed by Viscusi 

and Aldy (2003), based on a series of 

studies primarily describing simple 

accidents—to upwards of $5.1 million 

per case—which reflects work 

developed by Magat, Viscusi & Huber 

(1996) for non-fatal cancer. The latter 

number is based on an approach that 

places a willingness-to-pay value to 

avoid serious illness that is calibrated 

relative to the value of an avoided 

fatality. OSHA (2006) previously used 

this approach in the Final Economic 

Analysis (FEA) supporting its 

hexavalent chromium final rule, and 

EPA (2003) used this approach in its 

Stage 2 Disinfection and Disinfection 

Byproducts Rule concerning regulation 

of primary drinking water. Based on 

Magat, Viscusi & Huber (1996), EPA 

used studies on the willingness-to-pay 

to avoid nonfatal lymphoma and 

chronic bronchitis as a basis for valuing 

a case of nonfatal cancer at 58.3 percent 

of the value of a fatal cancer. OSHA’s 

estimate of $5.1 million for an avoided 

case of non-fatal cancer is based on this 

58.3 percent figure. 

The Agency believes this range of 

estimates is descriptive of the value of 

preventing morbidity associated with 

moderate to severe silicosis, as well as 

the morbidity preceding mortality due 

to other causes enumerated here—lung 

cancer, lung diseases other than cancer, 

and renal disease.32 OSHA therefore is 

applying these values to those situations 

as well. 

The Agency is interested in public 

input on the issue of valuing the cost to 

society of non-fatal cases of moderate to 

severe silicosis, as well as the morbidity 

associated with other related diseases of 

the lung, and with renal disease. 

a. The Monetized Benefits of the 

Proposed Rule 

Table VIII–18 presents the estimated 

annualized (over 60 years, using a 0 

percent discount rate) benefits from 

each of these components of the 

valuation, and the range of estimates, 

based on risk model uncertainty 

(notably in the case of lung cancer), and 

the range of uncertainty regarding 

valuation of morbidity. (Mid-point 

estimates of the undiscounted benefits 

for each of the first 60 years are 

provided in the middle columns of 

Table VII–A–1 in Appendix VII–A in 

the PEA. The estimates by year reach a 

peak of $11.9 billion in the 60th year.) 

As shown, the full range of monetized 

benefits, undiscounted, for the proposed 

PEL of 50 mg/m3 runs from $3.2 billion 

annually, in the case of the lowest 

estimate of lung cancer risk and the 

lowest valuation for morbidity, up to 

$10.9 billion annually, for the highest of 

both. Note that the value of total 

benefits is more sensitive to the 

valuation of morbidity (ranging from 

$3.5 billion to $10.3 billion, given 

estimates at the midpoint of the lung 

cancer models) than to the lung cancer 

model used (ranging from $6.4 to $7.4 

billion, given estimates at the midpoint 

of the morbidity valuation).33

This comports with the very wide 

range of valuation for morbidity. At the 

low end of the valuation range, the total 

value of benefits is dominated by 

mortality ($3.4 billion out of $3.5 billion 

at the case frequency midpoint), 

whereas at the high end the majority of 

the benefits are related to morbidity 

($6.9 billion out of $10.3 billion at the 

case frequency midpoint). Also, the 

analysis illustrates that most of the 

morbidity benefits are related to 

silicosis cases that are not ultimately 

fatal. At the valuation and case 

frequency midpoint, $3.4 billion in 

benefits are related to mortality, $1.0 

billion are related to morbidity 

preceding mortality, and $2.4 billion are 

related to morbidity not preceding 

mortality. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Monetized Benefits 

b. A Suggested Adjustment to 

OSHA’s estimates of the monetized 

fatality and each avoided silica-related 

on the imputed value of each avoided 

benefits of the proposed rule are based 

constant over time. 

values have been assumed to remain 

disease. To this point, these imputed 

OSHA now would like to suggest that 

benefits to reflect the fact that the 

an adjustment be made to monetized 

such an increase in value over time. 

over time. Two related factors suggest 

avoided diseases will tend to increase 

imputed value of avoided fatalities and 

First, economic theory suggests that 

the value of reducing life-threatening 


EP12SE13.009</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

TABLE VIII-18 

Estimated Annualized Undiscounted Monetized Benefits of the Silica Proposal for Morbidit

PEL 50 j.Jg/m 3 100 j.J

Valuation Valua

Low Mid oint Hi h Low Midpo

Cases 

Fatalities - Total 

Low $3,074,165,270 $3,074,165,270 $3,074,165,270 $1,433,022,347 $1,433,02

Midpoint $3,436,186,835 $3,436,186,835 $3,436,186,835 $1,643,786,936 $1,643,78

High $3,798,208,401 $3,798,208,401 $3,798,208,401 $1,643,786,936 $1,643,78

Morbidity Preceding Mortality 

Low $21,907,844 $912,002,363 $1,802,096,882 $10,212,343 $425,12

Midpoint $24,487,768 $1,019,402,094 $2,014,316,421 $11,714,344 $487,65

High $27,067,692 $1,126,801,826 $2,226,535,959 $11,714,344 $487,65

Morbidity Not Preceding Mortality 

Total $58,844,551 $2,449,641,696 $4,840,438,842 $35,733,901 $1,487,56TOTAL 

Low $3,154,917,665 $6,435,809,329 $9,716,700,994 $1,478,968,592 $3,345,72

Midpoint $3,519,519,154 $6,905,230,626 $10,290,942,098 $1,691,235,181 $3,619,0

High $3,884,120,643 $7,374,651,923 $10,865,183,202 $1,691,235,181 $3,619,0

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation 

Regulatory Analysis 
Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56391 

34The results are similar if the historical period 

includes a major economic downturn (such as the 

United States has recently experienced). From 1929 

through 2003, a period in U.S. history that includes 

the Great Depression, real per capita income still 

grew at an average rate of 2.22 percent a year 

(Gomme and Rupert, 2004). 

35The EIA used DOE’s National Energy Modeling 

System (NEMS) to produce the Annual Energy 

Outlook (AEO) projections (EIA, 2011). Future per 

capita GDP was calculated by dividing the projected 

real gross domestic product each year by the 

projected U.S. population for that year. 36See, for example, EPA (2003, 2008). 

37Here and elsewhere throughout this section, 

unless otherwise noted, the term ‘‘discount rate’’ 

always refers to the real discount rate—that is, the 

discount rate net of any inflationary effects. 

and health-threatening risks will 

increase as real per capita income 

increases. With increased income, an 

individual’s health and life become 

more valuable relative to other goods 

because, unlike other goods, they are 

without close substitutes and in 

relatively fixed or limited supply. 

Expressed differently, as income 

increases, consumption will increase 

but the marginal utility of consumption 

will decrease. In contrast, added years 

of life (in good health) is not subject to 

the same type of diminishing returns— 

implying that an effective way to 

increase lifetime utility is by extending 

one’s life and maintaining one’s good 

health (Hall and Jones, 2007). 

Second, real per capita income has 

broadly been increasing throughout U.S. 

history, including recent periods. For 

example, for the period 1950 through 

2000, real per capita income grew at an 

average rate of 2.31 percent a year (Hall 

and Jones, 2007) 34 although real per 

capita income for the recent 25 year 

period 1983 through 2008 grew at an 

average rate of only 1.3 percent a year 

(U.S. Census Bureau, 2010). More 

important is the fact that real U.S. per 

capita income is projected to grow 

significantly in future years. For 

example, the Annual Energy Outlook 

(AEO) projections, prepared by the 

Energy Information Administration 

(EIA) in the Department of Energy 

(DOE), show an average annual growth 

rate of per capita income in the United 

States of 2.7 percent for the period 

2011–2035.35 The U.S. Environmental 

Protection Agency prepared its 

economic analysis of the Clean Air Act 

using the AEO projections. Although 

these estimates may turn out to be 

somewhat higher or lower than 

predicted, OSHA believes that it is 

reasonable to use the same AEO 

projections employed by DOE and EPA, 

and correspondingly projects that per 

capita income in the United States will 

increase by 2.7 percent a year. 

On the basis of the predicted increase 

in real per capita income in the United 

States over time and the expected 

resulting increase in the value of 

avoided fatalities and diseases, OSHA is 

considering adjusting its estimates of 

the benefits of the proposed rule to 

reflect the anticipated increase in their 

value over time. This type of adjustment 

has been recognized by OMB (2003), 

supported by EPA’s Science Advisory 

Board (EPA, 2000), and applied by 

EPA.36 OSHA proposes to accomplish 

this adjustment by modifying benefits in 

year i from [Bi] to [Bi * (1 + h)i], where 

‘‘h’’ is the estimated annual increase in 

the magnitude of the benefits of the 

proposed rule. 

What remains is to estimate a value 

for ‘‘h’’ with which to increase benefits 

annually in response to annual 

increases in real per capita income. 

Probably the most direct evidence of the 

value of ‘‘h’’ comes from the work of 

Costa and Kahn (2003, 2004). They 

estimate repeated labor market 

compensating wage differentials from 

cross-sectional hedonic regressions 

using census and fatality data from the 

Bureau of Labor Statistics for 1940, 

1950, 1960, 1970, and 1980. In addition, 

with the imputed income elasticity of 

the value of life on per capita GNP of 

1.7 derived from the 1940–1980 data, 

they then predict the value of an 

avoided fatality in 1900, 1920, and 

2000. Given the change in the value of 

an avoided fatality over time, it is 

possible to estimate a value of ‘‘h’’ of 3.4 

percent a year from 1900–2000; of 4.3 

percent a year from 1940–1980; and of 

2.5 percent a year from 1980–2000. 

Other, more indirect evidence comes 

from estimates in the economics 

literature on the income elasticity for 

the value of a statistical life. Viscusi and 

Aldy (2003) performed a meta-analysis 

on 50 wage-risk studies and concluded 

that the point estimates across a variety 

of model specifications ranged between 

0.5 and 0.6. Applied to a long-term 

increase in per capita income of about 

2.7 percent a year, this would suggest a 

value of ‘‘h’’ of about 1.5 percent a year. 

More recently, Kniesner, Viscusi, and 

Ziliak (2010), using panel data quintile 

regressions, developed an estimate of 

the overall income elasticity of the value 

of a statistical life of 1.44. Applied to a 

long-term increase in per capita income 

of about 2.7 percent a year, this would 

suggest a value of ‘‘h’’ of about 3.9 

percent a year. 

Based on the preceding discussion of 

these two approaches for estimating the 

annual increase in the value of the 

benefits of the proposed rule and the 

fact that, as previously noted, the 

projected increase in real per capita 

income in the United States has 

flattened in the most recent 25 year 

period, OSHA suggests a value of ‘‘h’’ of 

approximately 2 percent a year. The 

Agency invites comment on this 

estimate and on estimates of the income 

elasticity of the value of a statistical life. 

While the Agency believes that the 

rising value, over time, of health 

benefits is a real phenomenon that 

should be taken into account in 

estimating the annualized benefits of the 

proposed rule, OSHA is at this time 

only offering these adjusted monetized 

benefits as analytic alternatives for 

consideration. Table VIII–19, which 

follows the discussion on discounting 

monetized benefits, shows estimates of 

the monetized benefits of the proposed 

rule (under alternative discount rates) 

both with and without this suggested 

increase in monetized benefits over 

time. The Agency invites comment on 

this suggested adjustment to monetized 

benefits. 

4. Discounting of Monetized Benefits 

As previously noted, the estimated 

stream of benefits arising from the 

proposed silica rule is not constant from 

year to year, both because of the 45-year 

delay after the rule takes effect until all 

active workers obtain reduced silica 

exposure over their entire working lives 

and because of, in the case of lung 

cancer, a 15-year latency period 

between reduced exposure and a 

reduction in the probability of disease. 

An appropriate discount rate 37 is 

needed to reflect the timing of benefits 

over the 60-year period after the rule 

takes effect and to allow conversion to 

an equivalent steady stream of 

annualized benefits. 

a. Alternative Discount Rates for 

Annualizing Benefits 

Following OMB (2003) guidelines, 

OSHA has estimated the annualized 

benefits of the proposed rule using 

separate discount rates of 3 percent and 

7 percent. Consistent with the Agency’s 

own practices in recent proposed and 

final rules, OSHA has also estimated, for 

benchmarking purposes, undiscounted 

benefits—that is, benefits using a zero 

percent discount rate. 

The question remains, what is the 

‘‘appropriate’’ or ‘‘preferred’’ discount 

rate to use to monetize health benefits? 

The choice of discount rate is a 

controversial topic, one that has been 

the source of scholarly economic debate 

for several decades. However, in 

simplest terms, the basic choices 

involve a social opportunity cost of 

capital approach or social rate of time 

preference approach. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56392 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

The social opportunity cost of capital 

approach reflects the fact that private 

funds spent to comply with government 

regulations have an opportunity cost in 

terms of foregone private investments 

that could otherwise have been made. 

The relevant discount rate in this case 

is the pre-tax rate of return on the 

foregone investments (Lind, 1982b, pp. 

24–32). The rate of time preference 

approach is intended to measure the 

tradeoff between current consumption 

and future consumption, or in the 

context of the proposed rule, between 

current benefits and future benefits. The 

individual rate of time preference is 

influenced by uncertainty about the 

availability of the benefits at a future 

date and whether the individual will be 

alive to enjoy the delayed benefits. By 

comparison, the social rate of time 

preference takes a broader view over a 

longer time horizon—ignoring 

individual mortality and the riskiness of 

individual investments (which can be 

accounted for separately) . 

The usual method for estimating the 

social rate of time preference is to 

calculate the post-tax real rate of return 

on long-term, risk-free assets, such as 

U.S. Treasury securities (OMB, 2003). A 

variety of studies have estimated these 

rates of return over time and reported 

them to be in the range of approximately 

1–4 percent. 

In accordance with OMB Circular A– 

4 (2003), OSHA presents benefits and 

net benefits estimates using discount 

rates of 3 percent (representing the 

social rate of time preference) and 7 

percent (a rate estimated using the 

social cost of capital approach). The 

Agency is interested in any evidence, 

theoretical or applied, that would 

inform the application of discount rates 

to the costs and benefits of a regulation. 

b. Summary of Annualized Benefits 

Under Alternative Discount Rates 

Table VIII–19 presents OSHA’s 

estimates of the sum of the annualized 

benefits of the proposed rule, using 

alternative discount rates at 0, 3, and 7 

percent, with a breakout between 

construction and general industry, and 

including the possible alternative of 

increasing monetized benefits in 

response to annual increases in per 

capita income over time. 

Given that the stream of benefits 

extends out 60 years, the value of future 

benefits is sensitive to the choice of 

discount rate. As previously established 

in Table VIII–18, the undiscounted 

benefits range from $3.2 billion to $10.9 

billion annually. Using a 7 percent 

discount rate, the annualized benefits 

range from $1.6 billion to $5.4 billion. 

As can be seen, going from 

undiscounted benefits to a 7 percent 

discount rate has the effect of cutting 

the annualized benefits of the proposed 

rule approximately in half. 

The Agency’s best estimate of the total 

annualized benefits of the proposed 

rule—using a 3 percent discount rate 

with no adjustment for the increasing 

value of health benefits over time— is 

between $2.4 and $8.1 billion, with a 

mid-point value of $5.3 billion. 

As previously mentioned, OSHA has 

not attempted to estimate the monetary 

value of less severe silicosis cases, 

measured at 1/0 to 1/2 on the ILO scale. 

The Agency believes the economic loss 

to individuals with less severe cases of 

silicosis could be substantial, insofar as 

they may be accompanied by a lifetime 

of medical surveillance and lung 

damage, and potentially may require a 

change in career. However, many of 

these effects can be difficult to isolate 

and measure in economic terms, 

particularly in those cases where there 

is no obvious effect yet on physiological 

function or performance. The Agency 

invites public comment on this issue. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2


EP12SE13.010</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

PEL 

Discount Rate 

UndiscOlmted (0%) 

Discounted at 3%, with a 

suggested increased in 

monetized benefits over time 

Discounted at 3% 

Discounted at 7%, with a 

suggested increased in 

monetized benefits over time 

Discounted at 7% 

Table VIII-19 

Total Annual Monetized Benefits Resulting from a Reduction in Exposure to Crystalline Silica 

Due to Proposed PEL of 50 Ilg/m3 and Alternative PEL of 100 Ilg/m3 

($Billions) 

50 

Range Total Construction GI& Total Con

Maritime 

Low $3.2 $2.6 $0.5 $1.5 

Midpoint $7.0 $5.4 $1.6 $3.7 

High $lO.9 $8.2 $2.7 $5.9 

Low $2.9 $2.4 $0.5 $1.4 

Midpoint $6.4 $5.0 $1.5 $3.4 

High $9.9 $7.5 $2.4 $5.4 

Low $2.4 $2.0 $0.4 $1.1 

Midpoint $5.3 $4.1 $1.2 $2.8 

High $8.1 $6.1 $2.0 $4.4 

Low $2.0 $1.6 $0.3 $0.9 

Midpoint $4.3 $3.3 $1.0 $2.2 

High $6.6 $5.0 $1.6 $3.6 

Low $1.6 $1.3 $0.3 $0.8 

Midpoint $3.5 $2.7 $0.8 $1.8 

High $5.4 $4.1 $1.3 $2.9 

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Reg

Analysis 
56394 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

5. Net Benefits of the Proposed Rule 

OSHA has estimated, in Table VIII– 

20, the net benefits of the proposed rule 

(with a PEL of 50 mg/m3), based on the 

benefits and costs previously presented. 

Table VIII–20 also provides estimates of 

annualized net benefits for an 

alternative PEL of 100 mg/m3. Both the 

proposed rule and the alternative rule 

have the same ancillary provisions and 

an action level equal to half of the PEL 

in both cases. 

Table VIII–20 is being provided for 

informational purposes only. As 

previously noted, the OSH Act requires 

the Agency to set standards based on 

eliminating significant risk to the extent 

feasible. An alternative criterion of 

maximizing net (monetized) benefits 

may result in very different regulatory 

outcomes. Thus, this analysis of net 

benefits has not been used by OSHA as 

the basis for its decision concerning the 

choice of a PEL or of other ancillary 

requirements for this proposed silica 

rule. 

Table VIII–20 shows net benefits 

using alternative discount rates of 0, 3, 

and 7 percent for benefits and costs and 

includes a possible adjustment to 

monetized benefits to reflect increases 

in real per capita income over time. (An 

expanded version of Tables VIII–20, 

with a breakout of net benefits between 

construction and general industry/

maritime, is provided in Table VII–B–1 

in Appendix B, of the PEA.) OSHA has 

relied on a uniform discount rate 

applied to both costs and benefits. The 

Agency is interested in any evidence, 

theoretical or applied, that would 

support or refute the application of 

differential discount rates to the costs 

and benefits of a regulation. 

As previously noted, the choice of 

discount rate for annualizing benefits 

has a significant effect on annualized 

benefits. The same is true for net 

benefits. For example, the net benefits 

using a 7 percent discount rate for 

benefits are considerably smaller than 

the net benefits using a 0 percent 

discount rate, declining by more than 

half under all scenarios. (Conversely, as 

noted in Chapter V of the PEA, the 

choice of discount rate for annualizing 

costs has only a very minor effect on 

annualized costs.) 

Based on the results presented in 

Table VIII–20, OSHA finds: 

• While the net benefits of the 

proposed rule vary considerably— 

depending on the choice of discount 

rate used to annualize benefits and on 

whether the benefits being used are in 

the high, midpoint, or low range— 

benefits exceed costs for the proposed 

50 mg/m3 PEL in all cases that OSHA 

considered. 

• The Agency’s best estimate of the 

net annualized benefits of the proposed 

rule—using a uniform discount rate for 

both benefits and costs of 3 percent—is 

between $1.8 billion and $7.5 billion, 

with a midpoint value of $4.6 billion. 

• The alternative of a 100 mg/m3 PEL 

was found to have lower net benefits 

under all assumptions, relative to the 

proposed 50 mg/m3 PEL. However, for 

this alternative PEL, benefits were found 

to exceed costs in all cases that OSHA 

considered. 

6. Incremental Benefits of the Proposed 

Rule 

Incremental costs and benefits are 

those that are associated with increasing 

the stringency of the standard. A 

comparison of incremental benefits and 

costs provides an indication of the 

relative efficiency of the proposed PEL 

and the alternative PEL. Again, OSHA 

has conducted these calculations for 

informational purposes only and has not 

used this information as the basis for 

selecting the PEL for the proposed rule. 

OSHA provided, in Table VIII–20, 

estimates of the net benefits of an 

alternative 100 mg/m3 PEL. The 

incremental costs, benefits, and net 

benefits of going from a 100 mg/m3 PEL 

to a 50 mg/m3 PEL (as well as meeting 

a 50 mg/m3 PEL and then going to a 25 

mg/m3 PEL—which the Agency has 

determined is not feasible), for 

alternative discount rates of 3 and 7 

percent, are presented in Tables VIII–21 

and VIII–22. Table VIII–21 breaks out 

costs by provision and benefits by type 

of disease and by morbidity/mortality, 

while Table VIII–22 breaks out costs and 

benefits by major industry sector. As 

Table VIII–21 shows, at a discount rate 

of 3 percent, a PEL of 50 mg/m3, relative 

to a PEL of 100 mg/m3, imposes 

additional costs of $339 million per 

year; additional benefits of $2.5 billion 

per year, and additional net benefits of 

$2.16 billion per year. The proposed 

PEL of 50 mg/m3 also has higher net 

benefits using either a 3 percent or 7 

percent discount rate. 

Table VIII–22 continues this 

incremental analysis but with 

breakdowns between construction and 

general industry/maritime. This table 

shows that construction provides most 

of the incremental costs, but the 

incremental benefits are more evenly 

divided between the two sectors. 

Nevertheless, both sectors show strong 

positive net benefits, which are greater 

for the proposed PEL of 50 mg/m3 than 

the alternative of 100 mg/m3. 

Tables VIII–21 and VIII–22 

demonstrate that, across all discount 

rates, there are net benefits to be 

achieved by lowering exposures to 100 

mg/m3 and then, in turn, lowering them 

further to 50 mg/m3. However, the 

majority of the benefits and costs 

attributable to the proposed rule are 

from the initial effort to lower exposures 

to 100 mg/m3. Consistent with the 

previous analysis, net benefits decline 

across all increments as the discount 

rate for annualizing benefits increases. 

In addition to examining alternative 

PELs, OSHA also examined alternatives 

to other provisions of the standard. 

These alternatives are discussed in 

Section VIII.H of this preamble. 

TABLE VIII–20—ANNUAL MONETIZED NET BENEFITS RESULTING FROM A REDUCTION IN EXPOSURE TO CRYSTALLINE

SILICA DUE TO PROPOSED PEL OF 50 μg/m3 AND ALTERNATIVE PEL OF 100 μg/m3

[$Billions] 

PEL 

50 100 

Discount rate Range 

Undiscounted (0%) ................................................... Low ........................................................................... $2.5 $1.2 

Midpoint .................................................................... 6.4 3.4 

High .......................................................................... 10.2 5.6 

Discounted at 3%, with a suggested increased in 

monetized benefits over time.

Low ...........................................................................

Midpoint ....................................................................

High ..........................................................................

2.3 

5.8 

9.3 

1.1 

3.1 

5.1 

3% ............................................................................. Low ........................................................................... 1.8 0.8 

Midpoint .................................................................... 4.6 2.5 

High .......................................................................... 7.5 4.1 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56395 

TABLE VIII–20—ANNUAL MONETIZED NET BENEFITS RESULTING FROM A REDUCTION IN EXPOSURE TO CRYSTALLINE

SILICA DUE TO PROPOSED PEL OF 50 μg/m3 AND ALTERNATIVE PEL OF 100 μg/m3—Continued 

[$Billions] 

PEL 

50 100 

Discount rate Range 

Discounted at 7%, with a suggested increased in 

monetized benefits over time.

Low ...........................................................................

Midpoint ....................................................................

High ..........................................................................

1.3 

3.6 

5.9 

0.6 

1.9 

3.3 

7% ............................................................................. Low ........................................................................... 1.0 0.5 

Midpoint .................................................................... 2.8 1.5 

High .......................................................................... 4.7 2.6 

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Standards and Guidance, Office of Regulatory Analysis. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2


EP12SE13.011</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table VIII·21: Annualized Costs, Benefits and Incremental Benefds of OSHA's Proposed Silica Standard of 50 and 100 AUernative 

Millions ($2009) 

25l!g/m3 Incremental Costs/Benefits 5Ol!g/m3 Incremental Costs/Benefi

Discount Rate 3% 

Annualized Costs 

Engineering Controls (includes Abrasive Blasting) $330 $344 $0 $0 $330 $344 $187 $197 Respirators $421 $422 $330 $331 $91 $91 $88 $88 Exposure Assessment $203 $203 $131 $129 $73 $74 $26 $26 

Medical Surveillance $219 $227 $143 $148 $76 $79 $28 $29 

Training $49 $50 $0 $0 $49 $50 $0 $0 

Regulated Area or Access Control $85 $86 $66 $66 $19 

Total Annualized Costs (point estimate) $1,308 $1,332 $670 $674 $637 $658 $339 $351 

Annual Benefits: Number of Cases Prevented Cases Cases Cases Cases 

Fatal Lung Cancers (midpoint estimate) """237 75 """"162 Fatal Silicosis & other Non-Malignant 527 152 375 186 Respiratory Diseases Fatal Renal Disease 258 108 91 

Silica-Related Mortality 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,116 

Silicosis Morbidity 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $544 

Monetized Annual Benefds (midpoint estimate) $7,030 $4,684 $1,776 $1,188 $5,254 $3,495 $2,495 $1,659 

Net Benefits $5722 $3352 $1105 $514 $4617 $2838 $2157 $1308 

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory Analysis 

* Benefits are assessed over a 50-year time horizon, during which it is assumed that economic conditions remain constant. Costs are annualized ov

equipment expenditures, which are annualized over the life of the equipment. Annualized costs are assumed to continue at the same level for sixty y

assuming that economic conditions remain constant for the sixty year time horizon, 

EP12SE13.012</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table VIII-22: Annualized Costs, Benefits and Incremental Benefits of OSHA's Proposed Silica Standard of 50 1l9/m' and 100 1l9/m' Alternative, by Major 

Millions ($2009) 

25!,!s/m3 Incremental Costs/Benefits 50 (!s/m' Incremental Costs/Be

Discount Rate 

Annualized Costs 

Construction $1,043 $1,062 $548 $551 $495 $511 $233 $24

General Industry/Maritime $264 $270 $122 $123 $143 $147 $106 $11

----

Total Annualized Costs $1,308 $1,332 $670 $674 $637 $658 $339 $35

Annual Benefits: Number of Cases 

Prevented Cases Cases Cases Cases 

Silica-Related Mortality 

Construction 802 $3,804 $2,504 235 $1,109 $746 567 $2,695 $1,758 242 $1,158 $760 

Generallndustry/Maritime 221 $1,007 $657 100 $434 $283 121 $573 $374 115 $545 $356 

Total 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,116 

Silicosis Morbidity 

Construction 1,157 $1,451 $996 77 $96 $66 1,080 $1,354 $930 161 $202 $139 

Generallndustry/Maritime 613 $768 $528 109 $136 $94 504 $632 $434 471 $590 $405 

Total 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $544 

Monetized Annual Benefits (midpoint 

estimate) 

Construction $5,255 $3,500 $1,205 $812 $4,049 $2,688 $1,360 $898 

General Industry/Maritime $1,775 $1,164 $570 $377 $1,205 $808 $1,135 $761 

Total $7,030 $4,684 $1,776 $1,188 $5,254 $3,495 $2,495 $1,659 

Net Benefits 

Construction $4,211 $2,437 $657 $261 $3,555 $2,177 $1,127 $658 

General Industry/Maritime $1,511 $914 $448 $254 $1,062 $661 $1,029 $651 

Total $5,722 $3,352 $1,105 $514 $4,617 $2,838 $2,157 $1,308 

Source: U,S, Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory Analysis 

* Benefits are assessed over a 60-year time horizon, during which it is assumed that economic conditions remain constant Costs are annualized ove

equipment expenditures, which are annualized over the life of the equipment Annualized costs are assumed to continue at the same level for sixty y

assuming that economic conditions remain constant for the sixty year time horizon, 
56398 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

7. Sensitivity Analysis 

In this section, OSHA presents the 

results of two different types of 

sensitivity analysis to demonstrate how 

robust the estimates of net benefits are 

to changes in various cost and benefit 

parameters. In the first type of 

sensitivity analysis, OSHA made a 

series of isolated changes to individual 

cost and benefit input parameters in 

order to determine their effects on the 

Agency’s estimates of annualized costs, 

annualized benefits, and annualized net 

benefits. In the second type of 

sensitivity analysis—a so-called ‘‘breakeven’’ analysis—OSHA also investigated 

isolated changes to individual cost and 

benefit input parameters, but with the 

objective of determining how much they 

would have to change for annualized 

costs to equal annualized benefits. 

Again, the Agency has conducted 

these calculations for informational 

purposes only and has not used these 

results as the basis for selecting the PEL 

for the proposed rule. 

Analysis of Isolated Changes to Inputs 

The methodology and calculations 

underlying the estimation of the costs 

and benefits associated with this 

rulemaking are generally linear and 

additive in nature. Thus, the sensitivity 

of the results and conclusions of the 

analysis will generally be proportional 

to isolated variations a particular input 

parameter. For example, if the estimated 

time that employees need to travel to 

(and from) medical screenings were 

doubled, the corresponding labor costs 

would double as well. 

OSHA evaluated a series of such 

changes in input parameters to test 

whether and to what extent the general 

conclusions of the economic analysis 

held up. OSHA first considered changes 

to input parameters that affected only 

costs and then changes to input 

parameters that affected only benefits. 

Each of the sensitivity tests on cost 

parameters had only a very minor effect 

on total costs or net costs. Much larger 

effects were observed when the benefits 

parameters were modified; however, in 

all cases, net benefits remained 

significantly positive. On the whole, 

OSHA found that the conclusions of the 

analysis are reasonably robust, as 

changes in any of the cost or benefit 

input parameters still show significant 

net benefits for the proposed rule. The 

results of the individual sensitivity tests 

are summarized in Table VIII–23 and 

are described in more detail below. 

In the first of these sensitivity test 

where OSHA doubled the estimated 

portion of employees in regulated areas 

requiring disposable clothing, from 10 

to 20 percent, and estimates of other 

input parameters remained unchanged, 

Table VIII–23 shows that the estimated 

total costs of compliance would increase 

by $3.6 million annually, or by about 

0.54 percent, while net benefits would 

also decline by $3.6 million, from 

$4,582 million to $4,528 million 

annually. 

In a second sensitivity test, OSHA 

decreased the estimated current 

prevalence of baseline silica training by 

half, from 50 percent to 25 percent. As 

shown in Table VIII–23, if OSHA’s 

estimates of other input parameters 

remained unchanged, the total 

estimated costs of compliance would 

increase by $7.9 million annually, or by 

about 1.19 percent, while net benefits 

would also decline by $7.9 million 

annually, from $4,532 million to $4,524 

million annually. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56399 

In a third sensitivity test, OSHA 

doubled the estimated travel time for 

employees to and from medical exams 

from 60 to 120 minutes. As shown in 

Table VIII–23, if OSHA’s estimates of 

other input parameters remained 

unchanged, the total estimated costs of 

compliance would increase by $1.4 

million annually, or by about 0.22 

percent, while net benefits would also 

decline by $1.4 million annually, from 

$4,532 million to $4,530 million 

annually. 

In a fourth sensitivity test, OSHA 

reduced its estimate of the number of 

workers who could be represented by an 

exposure monitoring sample from four 

to three. This would have the effect of 

increasing such costs by one-third. As 

shown in Table VIII–23, if OSHA’s 

estimates of other input parameters 

remained unchanged, the total 

estimated costs of compliance would 

increase by $24.8 million annually, or 

by about 3.77 percent, while net benefits 

would also decline by $24.8 million 

annually, from $4,532 million to $4,507 

million annually. 

In a fifth sensitivity test, OSHA 

increased by 50 percent the size of the 

productivity penalty arising from the 

use of engineering controls in 

construction. As shown in Table VIII– 


mstockstill on DSK4VPTVN1PROD with PROPOSALS2EP12SE13.013</GPH>
56400 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

23, if OSHA’s estimates of other input 

parameters remained unchanged, the 

total estimated costs of compliance 

would increase by $35.8 million 

annually, or by about 5.44 percent (and 

by 7.0 percent in construction), while 

net benefits would also decline by $35.8 

million annually, from $4,532 million to 

$4,496 million annually. 

In a sixth sensitivity test, based on the 

discussion in Chapter V of this PEA, 

OSHA reduced the costs of respirator 

cartridges to reflect possible reductions 

in costs since the original costs per filter 

were developed in 2003, and inflated to 

current dollars. For this purpose, OSHA 

reduced respirator filter costs by 40 

percent to reflect the recent lowerquartile estimates of costs relative to the 

costs used in OSHA’s primary analysis. 

As shown in Table VIII–23, the total 

estimated costs of compliance would be 

reduced by $21.2 million annually, or 

by about 3.23 percent, while net benefits 

would also increase by $21.2 million 

annually, from $4,532 million to $4,553 

million annually. 

In a seventh sensitivity test, OSHA 

reduced the average crew size in general 

industry and maritime subject to a 

‘‘unit’’ of engineering controls from 4 to 

3. This would have the effect of 

increasing such costs by one-third. As 

shown in Table VIII–23, if OSHA’s 

estimates of other input parameters 

remained unchanged, the total 

estimated costs of compliance would 

increase by $20.8 million annually, or 

by about 3.16 percent (and by 14.2 

percent in general industry and 

maritime), while net benefits would also 

decline by $20.8 million annually, from 

$4,532 million to $4,511 million 

annually. 

In an eighth sensitivity test, OSHA 

considered the effect on annualized net 

benefits of varying the discount rate for 

costs and the discount rate for benefits 

separately. In particular, the Agency 

examined the effect of reducing the 

discount rate for costs from 7 percent to 

3 percent. As indicated in Table VIII–23, 

this parameter change lowers the 

estimated annualized cost by $20.6 

million, or 3.13 percent. Total 

annualized net benefits would increase 

from $4,532 million annually to $4,552 

million annually. 

The Agency also performed 

sensitivity tests on several input 

parameters used to estimate the benefits 

of the proposed rule. In the first two 

tests, in an extension of results 

previously presented in Table VIII–21, 

the Agency examined the effect on 

annualized net benefits of employing 

the high-end estimate of the benefits, as 

well as the low-end estimate. As 

discussed previously, the Agency 

examined the sensitivity of the benefits 

to both the number of different fatal 

lung cancer cases prevented, as well as 

the valuation of individual morbidity 

cases. Table VIII–23 presents the effect 

on annualized net benefits of using the 

extreme values of these ranges, the high 

mortality count and high morbidity 

valuation case, and the low mortality 

count and low morbidity valuation case. 

As indicated, using the high estimate of 

mortality cases prevented and morbidity 

valuation, the benefits rise by 56% to 

$8.1 billion, yielding net benefits of $7.5 

billion. For the low estimate of both 

cases and valuation, the benefits decline 

by 54 percent, to $2.4 billion, yielding 

net benefits of $1.7 billion. 

In the third sensitivity test of benefits, 

the Agency examined the effect of 

raising the discount rate for benefits to 

7 percent. The fourth sensitivity test of 

benefits examines the effect of adjusting 

monetized benefits to reflect increases 

in real per capita income over time. The 

results of these two sensitivity tests 

were previously shown in Table VIII–20 

and are repeated in Table VIII–23. 

Raising the interest rate to 7 percent 

lowers the estimated benefits by 33 

percent, to $3.5 billion, yielding 

annualized net benefits of $2.8 billion. 

Adjusting monetized benefits to reflect 

increases in real per capita income over 

time raises the benefits by 22 percent, to 

$6.3 billion, yielding net benefits of $5.7 

billion. 

‘‘Break-Even’’ Analysis 

OSHA also performed sensitivity tests 

on several other parameters used to 

estimate the net costs and benefits of the 

proposed rule. However, for these, the 

Agency performed a ‘‘break-even’’ 

analysis, asking how much the various 

cost and benefits inputs would have to 

vary in order for the costs to equal, or 

break even with, the benefits. The 

results are shown in Table VIII–24. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

In one break-even test on cost 

billion, or 689 percent. 

reached if costs increased by $4.5 

Table VIII–24, this point would be 

costs to equal benefits. As shown in 

costs would have to increase in order for 

estimates, OSHA examined how much 

In a second test, looking specifically 

costs, the Agency found that these costs 

at the estimated engineering control 

benefits. 

or 1,318 percent, for costs to equal 

would need to increase by $4.5 billion, 

In a third sensitivity test, on benefits, 

total valuation of prevented mortality 

the costs to equal the benefits. Since the 

would need to be reduced in order for 

avoided illness or an avoided fatality 

estimated monetary valuation of an 

OSHA examined how much its 

substantial net benefits. Only through a 

held constant, the rule still has 

estimated value of an avoided fatality is 

associated with the rule, but the 

is attached to an avoided illness 

In other words, for example, if no value 

break-even point for each is impossible. 

costs are $0.6 billion, an independent 

exceed $1.9 billion, while the estimated 

and morbidity are each estimated to 


EP12SE13.014</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Total Costs 

Engineering Control Costs 

Benefits Valuation per Case Avoided 

Monetized Benefit per Fatality Avoided* 

Monetized Benefit per Illness Avoided* 

Cases Avoided 

Deaths Avoided* 

Illnesses Avoided* 

Table VIII-24 

Break-Even Sensitivity Analysis 

OSHA's Best Estimate 

of Annualized Cost or 

Benefit Factor 

$657,892,211 

$343,818,700 

$8,700,000 $2,575,000 

688 

1,585 

Factor Value at which 

Benefits Equal Costs 

$5,189,700,790 $4,875,627,279 

$1,102,889 

$326,430 

87 

201 

Required 

Dollar/N u

Chan

$4,53$4,53

-$

-$

*Note: The total estimated value of prevented mortality or morbidity alone exceeds the estimated cost of the rule, providi

Accordingly, these numbers represent a reduction in the composite valuation of an avoided fatality or illness or in the com

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analys
56402 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

reduction in the estimated net value of 

both components is a break-even point 

possible. 

The Agency, therefore, examined how 

large an across-the-board reduction in 

the monetized value of all avoided 

illnesses and fatalities would be 

necessary for the benefits to equal the 

costs. As shown in Table VIII–24, an 87 

percent reduction in the monetized 

value of all avoided illnesses and 

fatalities would be necessary for costs to 

equal benefits, reducing the estimated 

value to $1.1 million per life saved, and 

an equivalent percentage reduction to 

about $0.3 million per illness prevented. 

In a fourth break-even sensitivity test, 

OSHA estimated how many fewer silicarelated fatalities and illnesses would be 

required for benefits to equal costs. 

Paralleling the previous discussion, 

eliminating either the prevented 

mortality or morbidity cases alone 

would be insufficient to lower benefits 

to the break-even point. The Agency 

therefore examined them as a group. As 

shown in Table VIII–24, a reduction of 

87 percent, for both simultaneously, is 

required to reach the break-even point— 

600 fewer mortality cases prevented 

annually, and 1,384 fewer morbidity 

cases prevented annually. 

Taking into account both types of 

sensitivity analysis the Agency 

performed on its point estimates of the 

annualized costs and annualized 

benefits of the proposed rule, the results 

demonstrate that net benefits would be 

positive in all plausible cases tested. In 

particular, this finding would hold even 

with relatively large variations in 

individual input parameters. 

Alternately, one would have to imagine 

extremely large changes in costs or 

benefits for the rule to fail to produce 

net benefits. OSHA concludes that its 

finding of significant net benefits 

resulting from the proposed rule is a 

robust one. 

OSHA welcomes input from the 

public regarding all aspects of this 

sensitivity analysis, including any data 

or information regarding the accuracy of 

the preliminary estimates of compliance 

costs and benefits and how the 

estimates of costs and benefits may be 

affected by varying assumptions and 

methodological approaches. 

H. Regulatory Alternatives 

This section discusses various 

regulatory alternatives to the proposed 

OSHA silica standard. OSHA believes 

that this presentation of regulatory 

alternatives serves two important 

functions. The first is to explore the 

possibility of less costly ways (than the 

proposed rule) to provide an adequate 

level of worker protection from 

exposure to respirable crystalline silica. 

The second is tied to the Agency’s 

statutory requirement, which underlies 

the proposed rule, to reduce significant 

risk to the extent feasible. If, based on 

evidence presented during notice and 

comment, OSHA is unable to justify its 

preliminary findings of significant risk 

and feasibility as presented in this 

preamble to the proposed rule, the 

Agency must then consider regulatory 

alternatives that do satisfy its statutory 

obligations. 

Each regulatory alternative presented 

here is described and analyzed relative 

to the proposed rule. Where 

appropriate, the Agency notes whether 

the regulatory alternative, to be a 

legitimate candidate for OSHA 

consideration, requires evidence 

contrary to the Agency’s findings of 

significant risk and feasibility. To 

facilitate comment, the regulatory 

alternatives have been organized into 

four categories: (1) Alternative PELs to 

the proposed PEL of 50 mg/m3; (2) 

regulatory alternatives that affect 

proposed ancillary provisions; (3) a 

regulatory alternative that would modify 

the proposed methods of compliance; 

and (4) regulatory alternatives 

concerning when different provisions of 

the proposed rule would take effect. 

Alternative PELs 

OSHA is proposing a new PEL for 

respirable crystalline silica of 50 mg/m3

for all industry sectors covered by the 

rule. OSHA’s proposal is based on the 

requirements of the Occupational Safety 

and Health Act (OSH Act) and court 

interpretations of the Act. For health 

standards issued under section 6(b)(5) of 

the OSH Act, OSHA is required to 

promulgate a standard that reduces 

significant risk to the extent that it is 

technologically and economically 

feasible to do so. See Section II of this 

preamble, Pertinent Legal Authority, for 

a full discussion of OSHA legal 

requirements. 

OSHA has conducted an extensive 

review of the literature on adverse 

health effects associated with exposure 

to respirable crystalline silica. The 

Agency has also developed estimates of 

the risk of silica-related diseases 

assuming exposure over a working 

lifetime at the proposed PEL and action 

level, as well as at OSHA’s current 

PELs. These analyses are presented in a 

background document entitled 

‘‘Respirable Crystalline Silica—Health 

Effects Literature Review and 

Preliminary Quantitative Risk 

Assessment’’ and are summarized in 

this preamble in Section V, Health 

Effects Summary, and Section VI, 

Summary of OSHA’s Preliminary 

Quantitative Risk Assessment, 

respectively. The available evidence 

indicates that employees exposed to 

respirable crystalline silica well below 

the current PELs are at increased risk of 

lung cancer mortality and silicosis 

mortality and morbidity. Occupational 

exposures to respirable crystalline silica 

also may result in the development of 

kidney and autoimmune diseases and in 

death from other nonmalignant 

respiratory diseases. As discussed in 

Section VII, Significance of Risk, in this 

preamble, OSHA preliminarily finds 

that worker exposure to respirable 

crystalline silica constitutes a 

significant risk and that the proposed 

standard will substantially reduce this 

risk. 

Section 6(b) of the OSH Act (29 U.S.C. 

655(b)) requires OSHA to determine that 

its standards are technologically and 

economically feasible. OSHA’s 

examination of the technological and 

economic feasibility of the proposed 

rule is presented in the Preliminary 

Economic Analysis and Initial 

Regulatory Flexibility Analysis (PEA), 

and is summarized in this section 

(Section VIII) of this preamble. For 

general industry and maritime, OSHA 

has preliminarily concluded that the 

proposed PEL of 50 mg/m3 is 

technologically feasible for all affected 

industries. For construction, OSHA has 

preliminarily determined that the 

proposed PEL of 50 mg/m3 is feasible in 

10 out of 12 of the affected activities. 

Thus, OSHA preliminarily concludes 

that engineering and work practices will 

be sufficient to reduce and maintain 

silica exposures to the proposed PEL of 

50 mg/m3 or below in most operations 

most of the time in the affected 

industries. For those few operations 

within an industry or activity where the 

proposed PEL is not technologically 

feasible even when workers use 

recommended engineering and work 

practice controls, employers can 

supplement controls with respirators to 

achieve exposure levels at or below the 

proposed PEL. 

OSHA developed quantitative 

estimates of the compliance costs of the 

proposed rule for each of the affected 

industry sectors. The estimated 

compliance costs were compared with 

industry revenues and profits to provide 

a screening analysis of the economic 

feasibility of complying with the revised 

standard and an evaluation of the 

potential economic impacts. Industries 

with unusually high costs as a 

percentage of revenues or profits were 

further analyzed for possible economic 

feasibility issues. After performing these 

analyses, OSHA has preliminarily 

concluded that compliance with the 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56403 

requirements of the proposed rule 

would be economically feasible in every 

affected industry sector. 

OSHA has examined two regulatory 

alternatives (named Regulatory 

Alternatives #1 and #2) that would 

modify the PEL for the proposed rule. 

Under Regulatory Alternative #1, the 

proposed PEL would be changed from 

50 mg/m3 to 100 mg/m3 for all industry 

sectors covered by the rule, and the 

action level would be changed from 25 

mg/m3 to 50 mg/m3 (thereby keeping the 

action level at one-half of the PEL). 

Under Regulatory Alternative #2, the 

proposed PEL would be lowered from 

50 mg/m3 to 25 mg/m3 for all industry 

sectors covered by the rule, while the 

action level would remain at 25 mg/m3

(because of difficulties in accurately 

measuring exposure levels below 25 mg/ 

m3). 

Tables VIII–25 and VIII–26 present, 

for informational purposes, the 

estimated costs, benefits, and net 

benefits of the proposed rule under the 

proposed PEL of 50 mg/m3 and for the 

regulatory alternatives of a PEL of 100 

mg/m3 and a PEL of 25 mg/m3

(Regulatory Alternatives # 1 and #2), 

using alternative discount rates of 3 and 

7 percent. These two tables also present 

the incremental costs, the incremental 

benefits, and the incremental net 

benefits of going from a PEL of 100 mg/ 

m3 to the proposed PEL of 50 mg/m3 and 

then of going from the proposed PEL of 

50 mg/m3 to a PEL of 25 mg/m3. Table 

VIII–25 breaks out costs by provision 

and benefits by type of disease and by 

morbidity/mortality, while Table VIII– 

26 breaks out costs and benefits by 

major industry sector. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2


EP12SE13.015</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table VIII-25: Annualized Costs, Benefits and Incremental Benefits of OSHA's Proposed Silica Standard of 50 !-191m3 and 100 !-191m3 Alternative 

Millions ($2009) 

25 Incremental Costs/Benefits 50 Incremental Costs/Benef

Discount Rate 3% 

Annualized Costs 

Engineering Controls (includes Abrasive Blastlng) $330 $344 $0 $0 $330 $344 $187 $197 Respirators $421 $422 $330 $331 $91 $91 $88 $88 Exposure Assessment $203 $203 $131 $129 $73 $74 $26 $26 Medical Surveillance $219 $227 $143 $148 $76 $79 $28 $29 

Training $49 $50 $0 $0 $49 $50 $0 $0 

Regulated Area or Access Control $85 $86 $66 $66 $19 

Total Annualized Costs (point estimate) $1,308 $1,332 $670 $674 $637 $658 $339 $351 

Annual Benefits: Number of Cases Prevented Cases Cases Cases Cases 

Fatal Lung Cancers (midpoint estimate) 237 ----ys ---w2 79 Fatal Silicosis & other Non-Malignant 527 152 375 186 Respiratory Diseases Fatal Renal Disease 258 108 151 91 

Silica-Related Mortality 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,116 

Silicosis Morbidity 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $544 

Monetized Annual Benefits (midpoint estimate) $7,030 $4,664 $1,776 $1,188 $5,254 $3,495 $2,495 $1,659 

Net Benefits $5722 $3352 $1105 $514 $4617 $2838 $2157 $1308 

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory Analysis 

* Benefits are assessed over a 60-year time horizon, during which it is assumed that economic conditions remain constant. Costs are annualized ov

exception of equipment expenditures, which are annualized over the life of the equipment. Annualized costs are assumed to continue at the same le

is consistent with assuming that economic conditions remain constant for the sixty year time horizon, 
As Tables VIII–25 and VIII–26 show, 

going from a PEL of 100 mg/m3 to a PEL 

of 50 mg/m3 would prevent, annually, an 

additional 357 silica-related fatalities Based on its preliminary findings that 

and an additional 632 cases of silicosis. 


EP12SE13.016</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table VIII-26: Annualized Costs, Benefits and Incremental Benefits of OSHA's Proposed Silica Standard of 50 I'g/m' and 100 I'g/m' Alternative, by Major 

Millions ($2009) 

25!:19/m3 Incremental Costs/Benefits 50 !:I9/m3 Incremental Costs/Be

Discount Rate 

Annualized Costs 

Construction $1,043 $1,062 $548 $551 $495 $511 $233 $24

General Industry/Maritime $264 $270 $122 $123 $143 $147 $106 $11

---- --- ---- --- ---- --- --- --- 

Total Annualized Costs $1,308 $1,332 $670 $674 $637 $658 $339 $35

Annual Benefits: Number of Cases 

Prevented Cases Cases Cases Cases 

Silica-Related Mortality 

Construction 802 $3,804 $2,504 235 $1,109 $746 567 $2,695 $1,758 242 $1,158 $760 

General Industry/Maritime 221 $1,007 $657 100 $434 $283 121 $573 $374 115 $545 $356 

Total 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,116 

Silicosis Morbidity 

Construction 1,157 $1,451 $996 77 $96 $66 1,080 $1,354 $930 161 $202 $139 

General Industry/Maritime 613 $768 $528 109 $136 $94 504 $632 $434 471 $590 $405 

Total 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $544 

Monetized Annual Benefits (midpoint 

estimate) 

Construction $5,255 $3,500 $1,205 $812 $4,049 $2,688 $1,360 $898 

General Industry/Maritime $1,775 $1,184 $570 $377 $1,205 $808 $1,135 $761 

Total $7,030 $4,684 $1,776 $1,188 $5,254 $3,495 $2,495 $1,659 

Net Benefits 

Construction $4,211 $2,437 $657 $261 $3,555 $2,177 $1,127 $658 

General Industry/Maritime $1,511 $914 $448 $254 $1,062 $661 $1,029 $651 

Total $5,722 $3352 $1.105 $514 $4,617 ill38 $1,308 

Source: U,S, Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory Analysis 

* Benefits are assessed over a 60-year time horizon, during which it is assumed that economic conditions remain constant. Costs are annualized ove

exception of equipment expenditures, which are annualized over the life of the equipment. Annualized costs are assumed to continue at the same le

is consistent with assuming that economic conditions remain constant for the sixty year time horizon. 
56406 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

the proposed PEL of 50 mg/m3

significantly reduces worker risk from 

silica exposure (as demonstrated by the 

number of silica-related fatalities and 

silicosis cases avoided) and is both 

technologically and economically 

feasible, OSHA cannot propose a PEL of 

100 mg/m3 (Regulatory Alternative #1) 

without violating its statutory 

obligations under the OSH Act. 

However, the Agency will consider 

evidence that challenges its preliminary 

findings. 

As previously noted, Tables VIII–25 

and VIII–26 also show the costs and 

benefits of a PEL of 25 mg/m3

(Regulatory Alternative #2), as well as 

the incremental costs and benefits of 

going from the proposed PEL of 50 mg/ 

m3 to a PEL of 25 mg/m3. Because OSHA 

determined that a PEL of 25 mg/m3

would not be feasible (that is, 

engineering and work practices would 

not be sufficient to reduce and maintain 

silica exposures to a PEL of 25 mg/m3 or 

below in most operations most of the 

time in the affected industries), the 

Agency did not attempt to identify 

engineering controls or their costs for 

affected industries to meet this PEL. 

Instead, for purposes of estimating the 

costs of going from a PEL of 50 mg/m3

to a PEL of 25 mg/m3, OSHA assumed 

that all workers exposed between 50 mg/ 

m3 and 25 mg/m3 would have to wear 

respirators to achieve compliance with 

the 25 mg/m3 PEL. OSHA then estimated 

the associated additional costs for 

respirators, exposure assessments, 

medical surveillance, and regulated 

areas (the latter three for ancillary 

requirements specified in the proposed 

rule). 

As shown in Tables VIII–25 and VIII– 

26, going from a PEL of 50 mg/m3 to a 

PEL of 25 mg/m3 would prevent, 

annually, an additional 335 silicarelated fatalities and an additional 186 

cases of silicosis. These estimates 

support OSHA’s preliminarily finding 

that there is significant risk remaining at 

the proposed PEL of 50 mg/m3. However, 

the Agency has preliminarily 

determined that a PEL of 25 mg/m3

(Regulatory Alternative #2) is not 

technologically feasible, and for that 

reason, cannot propose it without 

violating its statutory obligations under 

the OSH Act. 

Regulatory Alternatives That Affect 

Ancillary Provisions 

The proposed rule contains several 

ancillary provisions (provisions other 

the PEL), including requirements for 

exposure assessment, medical 

surveillance, silica training, and 

regulated areas or access control. As 

shown in Table VIII–25, these ancillary 

provisions represent approximately 

$223 million (or about 34 percent) of the 

total annualized costs of the rule of $658 

million (using a 7 percent discount 

rate). The two most expensive of the 

ancillary provisions are the 

requirements for medical surveillance, 

with annualized costs of $79 million, 

and the requirements for exposure 

monitoring, with annualized costs of 

$74 million. 

As proposed, the requirements for 

exposure assessment are triggered by the 

action level. As described in this 

preamble, OSHA has defined the action 

level for the proposed standard as an 

airborne concentration of respirable 

crystalline silica of 25 mg/m3 calculated 

as an eight-hour time-weighted average. 

In this proposal, as in other standards, 

the action level has been set at one-half 

of the PEL. 

Because of the variable nature of 

employee exposures to airborne 

concentrations of respirable crystalline 

silica, maintaining exposures below the 

action level provides reasonable 

assurance that employees will not be 

exposed to respirable crystalline silica 

at levels above the PEL on days when 

no exposure measurements are made. 

Even when all measurements on a given 

day may fall below the PEL (but are 

above the action level), there is some 

chance that on another day, when 

exposures are not measured, the 

employee’s actual exposure may exceed 

the PEL. When exposure measurements 

are above the action level, the employer 

cannot be reasonably confident that 

employees have not been exposed to 

respirable crystalline silica 

concentrations in excess of the PEL 

during at least some part of the work 

week. Therefore, requiring periodic 

exposure measurements when the 

action level is exceeded provides the 

employer with a reasonable degree of 

confidence in the results of the exposure 

monitoring. 

The action level is also intended to 

encourage employers to lower exposure 

levels in order to avoid the costs 

associated with the exposure assessment 

provisions. Some employers would be 

able to reduce exposures below the 

action level in all work areas, and other 

employers in some work areas. As 

exposures are lowered, the risk of 

adverse health effects among workers 

decreases. 

OSHA’s preliminary risk assessment 

indicates that significant risk remains at 

the proposed PEL of 50 mg/m3. Where 

there is continuing significant risk, the 

decision in the Asbestos case (Bldg. and 

Constr.Trades Dep’t, AFL–CIO v. Brock, 

838 F.2d 1258, 1274 (DC Cir. 1988)) 

indicated that OSHA should use its 

legal authority to impose additional 

requirements on employers to further 

reduce risk when those requirements 

will result in a greater than de minimis 

incremental benefit to workers’ health. 

OSHA’s preliminary conclusion is that 

the requirements triggered by the action 

level will result in a very real and 

necessary, but non-quantifiable, further 

reduction in risk beyond that provided 

by the PEL alone. OSHA’s choice of 

proposing an action level for exposure 

monitoring of one-half of the PEL is 

based on the Agency’s successful 

experience with other standards, 

including those for inorganic arsenic (29 

CFR 1910.1018), ethylene oxide (29 CFR 

1910.1047), benzene (29 CFR 

1910.1028), and methylene chloride (29 

CFR 1910.1052). 

As specified in the proposed rule, all 

workers exposed to respirable 

crystalline silica above the PEL of 50 mg/ 

m3 are subject to the medical 

surveillance requirements. This means 

that the medical surveillance 

requirements would apply to 15,172 

workers in general industry and 336,244 

workers in construction. OSHA 

estimates that 457 possible silicosis 

cases will be referred to pulmonary 

specialists annually as a result of this 

medical surveillance. 

OSHA has preliminarily determined 

that these ancillary provisions will: (1) 

help to ensure the PEL is not exceeded, 

and (2) minimize risk to workers given 

the very high level of risk remaining at 

the PEL. OSHA did not estimate, and 

the benefits analysis does not include, 

monetary benefits resulting from early 

discovery of illness. 

Because medical surveillance and 

exposure assessment are the two most 

costly ancillary provisions in the 

proposed rule, the Agency has 

examined four regulatory alternatives 

(named Regulatory Alternatives #3, #4, 

#5, and #6) involving changes to one or 

the other of these ancillary provisions. 

These four regulatory alternatives are 

defined below and the incremental cost 

impact of each is summarized in Table 

VIII–27. In addition, OSHA is including 

a regulatory alternative (named 

Regulatory Alternative #7) that would 

remove all ancillary provisions. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Under Regulatory Alternative #3, the 

action level would be raised from 25 mg/ 

m3 to 50 mg/m3 while keeping the PEL 

at 50 mg/m3. As a result, exposure triggered only if workers were exposed 

monitoring requirements would be 


EP12SE13.017</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

13% Discount Rate I 

Proposed Rule 

Option 3: PEL=50; AL=50 Option 4: PEL=50; AL =25, with 

medical surveillance triggered by AL 

Option 5: PEL=50; AL=25, with 

medical exams annually 

Option 6: PEL=50; AL=25, with 

surveillance triggered by AL and 

medical exams annually 

Proposed Rule 

Option 3: PEL=50; AL=50 Option 4: PEL=50; AL =25, with 

medical surveillance triggered by AL 

Option 5: PEL=50; AL=25, with 

medical exams annually 

Option 6: PEL=50; AL=25, with 

surveillance triggered by AL and 

medical exams annually 

Table VIII-27: Cost of Regulatory Alternatives Affecting Ancillary Provisions 

Cost Incremental Co

Construction GIIM Total Construction 

$494,826,699 $142,502,681 $637,329,380 

$457,686,162 $117,680,601 $575,366,763 -$37,140,537 -$

$606,697,624 $173,701,827 $780,399,451 $111,870,925 $

$561,613,766 $145,088,559 $706,702,325 $66,787,067 

$775,334,483 $203,665,685 $979,000,168 $280,507,784 $

Cost Incremental Co

Construction GIIM Total Construction 

$511,165,616 $146,726,595 $657,892,211 

$473,638,698 $121,817,396 $595,456,093 -$37,526,918 -$

$627,197,794 $179,066,993 $806,264,787 $132,371,095 $$575,224,843 $149,204,718 $724,429,561 $64,059,227 

$791,806,358 $208,339,741 $1,000,146,099 $280,640,742 $

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory A
56408 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

above the proposed PEL of 50 mg/m3. As 

shown in Table VIII–27, Regulatory 

Option #3 would reduce the annualized 

cost of the proposed rule by about $62 

million, using a discount rate of either 

3 percent or 7 percent. 

Under Regulatory Alternative #4, the 

action level would remain at 25 mg/m3

but medical surveillance would now be 

triggered by the action level, not the 

PEL. As a result, medical surveillance 

requirements would be triggered only if 

workers were exposed at or above the 

proposed action level of 25 mg/m3. As 

shown in Table VIII–27, Regulatory 

Option #4 would increase the 

annualized cost of the proposed rule by 

about $143 million, using a discount 

rate of 3 percent (and by about $169 

million, using a discount rate of 7 

percent). 

Under Regulatory Alternative #5, the 

only change to the proposed rule would 

be to the medical surveillance 

requirements. Instead of requiring 

workers exposed above the PEL to have 

a medical check-up every three years, 

those workers would be required to 

have a medical check-up annually. As 

shown in Table VIII–27, Regulatory 

Option #5 would increase the 

annualized cost of the proposed rule by 

about $69 million, using a discount rate 

of 3 percent (and by about $66 million, 

using a discount rate of 7 percent). 

Regulatory Alternative #6 would 

essentially combine the modified 

requirements in Regulatory Alternatives 

#4 and #5. Under Regulatory Alternative 

#6, medical surveillance would be 

triggered by the action level, not the 

PEL, and workers exposed at or above 

the action level would be required to 

have a medical check-up annually 

rather than triennially. The exposure 

monitoring requirements in the 

proposed rule would not be affected. As 

shown in Table VIII–27, Regulatory 

Option #6 would increase the 

annualized cost of the proposed rule by 

about $342 million, using a discount 

rate of either 3 percent or 7 percent. 

OSHA is not able to quantify the 

effects of these preceding four 

regulatory alternatives on protecting 

workers exposed to respirable 

crystalline silica at levels at or below 

the proposed PEL of 50 mg/m3—where 

significant risk remains. The Agency 

solicits comment on the extent to which 

these regulatory options may improve or 

reduce the effectiveness of the proposed 

rule. 

The final regulatory alternative 

affecting ancillary provisions, 

Regulatory Alternative #7, would 

eliminate all of the ancillary provisions 

of the proposed rule, including 

exposure assessment, medical 

surveillance, training, and regulated 

areas or access control. However, it 

should be carefully noted that 

elimination of the ancillary provisions 

does not mean that all costs for ancillary 

provisions would disappear. In order to 

meet the PEL, employers would still 

commonly need to do monitoring, train 

workers on the use of controls, and set 

up some kind of regulated areas to 

indicate where respirator use would be 

required. It is also likely that employers 

would increasingly follow the many 

recommendations to provide medical 

surveillance for employees. OSHA has 

not attempted to estimate the extent to 

which the costs of these activities would 

be reduced if they were not formally 

required, but OSHA welcomes comment 

on the issue. 

As indicated previously, OSHA 

preliminarily finds that there is 

significant risk remaining at the 

proposed PEL of 50 mg/m3. However, the 

Agency has also preliminarily 

determined that 50 mg/m3 is the lowest 

feasible PEL. Therefore, the Agency 

believes that it is necessary to include 

ancillary provisions in the proposed 

rule to further reduce the remaining 

risk. OSHA anticipates that these 

ancillary provisions will reduce the risk 

beyond the reduction that will be 

achieved by a new PEL alone. 

OSHA’s reasons for including each of 

the proposed ancillary provisions are 

detailed in Section XVI of this 

preamble, Summary and Explanation of 

the Standards. In particular, OSHA 

believes that requirements for exposure 

assessment (or alternately, using 

specified exposure control methods for 

selected construction operations) would 

provide a basis for ensuring that 

appropriate measures are in place to 

limit worker exposures. Medical 

surveillance is particularly important 

because individuals exposed above the 

PEL (which triggers medical 

surveillance in the proposed rule) are at 

significant risk of death and illness. 

Medical surveillance would allow for 

identification of respirable crystalline 

silica-related adverse health effects at an 

early stage so that appropriate 

intervention measures can be taken. 

OSHA believes that regulated areas and 

access control are important because 

they serve to limit exposure to 

respirable crystalline silica to as few 

employees as possible. Finally, OSHA 

believes that worker training is 

necessary to inform employees of the 

hazards to which they are exposed, 

along with associated protective 

measures, so that employees understand 

how they can minimize potential health 

hazards. Worker training on silicarelated work practices is particularly 

important in controlling silica 

exposures because engineering controls 

frequently require action on the part of 

workers to function effectively. 

OSHA expects that the benefits 

estimated under the proposed rule will 

not be fully achieved if employers do 

not implement the ancillary provisions 

of the proposed rule. For example, 

OSHA believes that the effectiveness of 

the proposed rule depends on regulated 

areas or access control to further limit 

exposures and on medical surveillance 

to identify disease cases when they do 

occur. 

Both industry and worker groups have 

recognized that a comprehensive 

standard is needed to protect workers 

exposed to respirable crystalline silica. 

For example, the industry consensus 

standards for crystalline silica, ASTM E 

1132–06, Standard Practice for Health 

Requirements Relating to Occupational 

Exposure to Respirable Crystalline 

Silica, and ASTM E 2626–09, Standard 

Practice for Controlling Occupational 

Exposure to Respirable Crystalline 

Silica for Construction and Demolition 

Activities, as well as the draft proposed 

silica standard for construction 

developed by the Building and 

Construction Trades Department, AFL– 

CIO, have each included comprehensive 

programs. These recommended 

standards include provisions for 

methods of compliance, exposure 

monitoring, training, and medical 

surveillance (ASTM, 2006; 2009; BCTD 

2001). Moreover, as mentioned 

previously, where there is continuing 

significant risk, the decision in the 

Asbestos case (Bldg. and Constr. Trades 

Dep’t, AFL–CIO v. Brock, 838 F.2d 1258, 

1274 (DC Cir. 1988)) indicated that 

OSHA should use its legal authority to 

impose additional requirements on 

employers to further reduce risk when 

those requirements will result in a 

greater than de minimis incremental 

benefit to workers’ health. OSHA 

preliminarily concludes that the 

additional requirements in the ancillary 

provisions of the proposed standard 

clearly exceed this threshold. 

A Regulatory Alternative That Modifies 

the Methods of Compliance 

The proposed standard in general 

industry and maritime would require 

employers to implement engineering 

and work practice controls to reduce 

employees’ exposures to or below the 

PEL. Where engineering and/or work 

practice controls are insufficient, 

employers would still be required to 

implement them to reduce exposure as 

much as possible, and to supplement 

them with a respiratory protection 

program. Under the proposed 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56409 

construction standard, employers would 

be given two options for compliance. 

The first option largely follows 

requirements for the general industry 

and maritime proposed standard, while 

the second option outlines, in Table 1 

(Exposure Control Methods for Selected 

Construction Operations) of the 

proposed rule, specific construction 

exposure control methods. Employers 

choosing to follow OSHA’s proposed 

control methods would be considered to 

be in compliance with the engineering 

and work practice control requirements 

of the proposed standard, and would 

not be required to conduct certain 

exposure monitoring activities. 

One regulatory alternative (Regulatory 

Alternative #8) involving methods of 

compliance would be to eliminate Table 

1 as a compliance option in the 

construction sector. Under this 

regulatory alternative, OSHA estimates 

that there would be no effect on 

estimated benefits but that the 

annualized costs of complying with the 

proposed rule (without the benefit of the 

Table 1 option in construction) would 

increase by $175 million, totally in 

exposure monitoring costs, using a 3 

percent discount rate (and by $178 

million using a 7 percent discount rate), 

so that the total annualized compliance 

costs for all affected establishments in 

construction would increase from $495 

to $670 million using a 3 percent 

discount rate (and from $511 to $689 

million using a 7 percent discount rate). 

Regulatory Alternatives That Affect the 

Timing of the Standard 

The proposed rule would become 

effective 60 days following publication 

of the final rule in the Federal Register. 

Provisions outlined in the proposed 

standard would become enforceable 180 

days following the effective date, with 

the exceptions of engineering controls 

and laboratory requirements. The 

proposed rule would require 

engineering controls to be implemented 

no later than one year after the effective 

date, and laboratory requirements 

would be required to begin two years 

after the effective date. 

One regulatory alternative (Regulatory 

Alternative #9) involving the timing of 

the standard would arise if, contrary to 

OSHA’s preliminary findings, a PEL of 

50 mg/m3 with an action level of 25 mg/ 

m3 were found to be technologically and 

economically feasible some time in the 

future (say, in five years), but not 

feasible immediately. In that case, 

OSHA might issue a final rule with a 

PEL of 50 mg/m3 and an action level of 

25 mg/m3 to take effect in five years, but 

at the same time issue an interim PEL 

of 100 mg/m3 and an action level of 50 

mg/m3 to be in effect until the final rule 

becomes feasible. Under this regulatory 

alternative, and consistent with the 

public participation and ‘‘look back’’ 

provisions of Executive Order 13563, 

the Agency could monitor compliance 

with the interim standard, review 

progress toward meeting the feasibility 

requirements of the final rule, and 

evaluate whether any adjustments to the 

timing of the final rule would be 

needed. Under Regulatory Alternative 

#9, the estimated costs and benefits 

would be somewhere between those 

estimated for a PEL of 100 mg/m3 with 

an action level of 50 mg/m3 and those 

estimated for a PEL of 50 mg/m3 with an 

action level of 25 mg/m3, the exact 

estimates depending on the length of 

time until the final rule is phased in. 

OSHA emphasizes that this regulatory 

alternative is contrary to the Agency’s 

preliminary findings of economic 

feasibility and, for the Agency to 

consider it, would require specific 

evidence introduced on the record to 

show that the proposed rule is not now 

feasible but would be feasible in the 

future. 

Although OSHA did not explicitly 

develop or quantitatively analyze any 

other regulatory alternatives involving 

longer-term or more complex phase-ins 

of the standard (possibly involving more 

delayed implementation dates for small 

businesses), OSHA is soliciting 

comments on this issue. Such a 

particularized, multi-year phase-in 

would have several advantages, 

especially from the viewpoint of 

impacts on small businesses. First, it 

would reduce the one-time initial costs 

of the standard by spreading them out 

over time, a particularly useful 

mechanism for small businesses that 

have trouble borrowing large amounts of 

capital in a single year. A differential 

phase-in for smaller firms would also 

aid very small firms by allowing them 

to gain from the control experience of 

larger firms. A phase-in would also be 

useful in certain industries—such as 

foundries, for example—by allowing 

employers to coordinate their 

environmental and occupational safety 

and health control strategies to 

minimize potential costs. However a 

phase-in would also postpone the 

benefits of the standard, recognizing, as 

described in Chapter VII of the PEA, 

that the full benefits of the proposal 

would take a number of years to fully 

materialize even in the absence of a 

phase-in. 

As previously discussed in the 

Introduction to this preamble, OSHA 

requests comments on these regulatory 

alternatives, including the Agency’s 

choice of regulatory alternatives (and 

whether there are other regulatory 

alternatives the Agency should 

consider) and the Agency’s analysis of 

them. 

I. Initial Regulatory Flexibility Analysis 

The Regulatory Flexibility Act, as 

amended in 1996, requires the 

preparation of an Initial Regulatory 

Flexibility Analysis (IRFA) for proposed 

rules where there would be a significant 

economic impact on a substantial 

number of small entities. (5 U.S.C. 601– 

612). Under the provisions of the law, 

each such analysis shall contain: 

1. A description of the impact of the 

proposed rule on small entities; 

2. A description of the reasons why 

action by the agency is being 

considered; 

3. A succinct statement of the 

objectives of, and legal basis for, the 

proposed rule; 

4. A description of and, where 

feasible, an estimate of the number of 

small entities to which the proposed 

rule will apply; 

5. A description of the projected 

reporting, recordkeeping, and other 

compliance requirements of the 

proposed rule, including an estimate of 

the classes of small entities which will 

be subject to the requirements and the 

type of professional skills necessary for 

preparation of the report or record; 

6. An identification, to the extent 

practicable, of all relevant Federal rules 

which may duplicate, overlap, or 

conflict with the proposed rule; and 

7. A description and discussion of any 

significant alternatives to the proposed 

rule which accomplish the stated 

objectives of applicable statutes and 

which minimize any significant 

economic impact of the proposed rule 

on small entities, such as 

(a) The establishment of differing 

compliance or reporting requirements or 

timetables that take into account the 

resources available to small entities; 

(b) The clarification, consolidation, or 

simplification of compliance and 

reporting requirements under the rule 

for such small entities; 

(c) The use of performance rather than 

design standards; and 

(d) An exemption from coverage of 

the rule, or any part thereof, for such 

small entities. 

5 U.S.C. 603, 607. 

The Regulatory Flexibility Act further 

states that the required elements of the 

IRFA may be performed in conjunction 

with or as part of any other agenda or 

analysis required by any other law if 

such other analysis satisfies the 

provisions of the IRFA. 5 U.S.C. 605. 

While a full understanding of OSHA’s 

analysis and conclusions with respect to 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56410 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

costs and economic impacts on small 

entities requires a reading of the 

complete PEA and its supporting 

materials, this IRFA will summarize the 

key aspects of OSHA’s analysis as they 

affect small entities. 

A Description of the Impact of the 

Proposed Rule on Small Entities 

Section VIII.F of this preamble 

summarized the impacts of the 

proposed rule on small entities. Tables 

VIII–12 and VIII–15 showed costs as a 

percentage of profits and revenues for 

small entities in general industry and 

maritime and in construction, 

respectively, classified as small by the 

Small Business Administration, and 

Tables VIII–13 and VIII–16 showed 

costs as a percentage of revenues and 

profits for business entities with fewer 

than 20 employees in general industry 

and maritime and in construction, 

respectively. (The costs in these tables 

were annualized using a discount rate of 

7 percent.) 

A Description of the Reasons Why 

Action by the Agency Is Being 

Considered 

Exposure to crystalline silica has been 

shown to increase the risk of several 

serious diseases. Crystalline silica is the 

only known cause of silicosis, which is 

a progressive respiratory disease in 

which respirable crystalline silica 

particles cause an inflammatory reaction 

in the lung, leading to lung damage and 

scarring, and, in some cases, to 

complications resulting in disability and 

death. In addition, many wellconducted investigations of exposed 

workers have shown that exposure 

increases the risk of mortality from lung 

cancer, chronic obstructive pulmonary 

disease (COPD), and renal disease. 

OSHA’s detailed analysis of the 

scientific literature and silica-related 

health risks are presented in the 

background document entitled 

‘‘Respirable Crystalline Silica—Health 

Effects Literature Review and 

Preliminary Quantitative Risk 

Assessment’’ (placed in Docket OSHA– 

2010–0034). 

Based on a review of over 60 

epidemiological studies covering more 

than 30 occupational groups, OSHA 

preliminarily concludes that crystalline 

silica is a human carcinogen. Most of 

these studies documented that exposed 

workers experience higher lung cancer 

mortality rates than do unexposed 

workers or the general population, and 

that the increase in lung cancer 

mortality is related to cumulative 

exposure to crystalline silica. These 

exposure-related trends strongly 

implicate crystalline silica as a likely 

causative agent. This is consistent with 

the conclusions of other government 

and public health organizations, 

including the International Agency for 

Research on Cancer (IARC), the Agency 

for Toxic Substance and Disease 

Registry (ATSDR), the World Health 

Organization (WHO), the U.S. 

Environmental Protection Agency 

(EPA), the National Toxicology Program 

(NTP), the National Academies of 

Science (NAS), the National Institute for 

Occupational Safety and Health 

(NIOSH), and the American Conference 

of Governmental Industrial Hygienists 

(ACGIH). 

OSHA believes that the strongest 

evidence for carcinogenicity comes from 

studies in five industry sectors 

(diatomaceous earth, pottery, granite, 

industrial sand, and coal mining) as 

well as a study by Steenland et al. 

(2001) that analyzed pooled data from 

10 occupational cohort studies; each of 

these studies found a positive 

relationship between exposure to 

crystalline silica and lung cancer 

mortality. Based on a variety of relative 

risk models fit to these data sets, OSHA 

estimates that the excess lifetime risk to 

workers exposed over a working life of 

45 years at the current general industry 

permissible exposure limit (PEL) 

(approximately 100 mg/m3 respirable 

crystalline silica) is between 13 and 60 

deaths per 1,000 workers. For exposure 

over a working life at the current 

construction and shipyard employment 

PELs (estimated to range between 250 

and 500 mg/m3), the estimated risk lies 

between 37 and 653 deaths per 1,000. 

Reducing these PELs to the proposed 

PEL of 50 mg/m3 respirable crystalline 

silica results in a substantial reduction 

of these risks, to a range estimated to be 

between 6 and 26 deaths per 1,000 

workers. 

OSHA has also quantitatively 

evaluated the mortality risk from nonmalignant respiratory disease, including 

silicosis and COPD. Risk estimates for 

silicosis mortality are based on a study 

by Mannetje et al. (2002), which pooled 

data from six worker cohort studies to 

derive a quantitative relationship 

between exposure and death rate for 

silicosis. For non-malignant respiratory 

disease, risk estimates are based on an 

epidemiologic study of diatomaceous 

earth workers, which included a 

quantitative exposure-response analysis 

(Park et al., 2002). For 45 years of 

exposure to the current general industry 

PEL, OSHA’s estimates of excess 

lifetime risk are 11 deaths per 1,000 

workers for the pooled analysis and 83 

deaths per 1,000 workers based on Park 

et al.’s (2002) estimates. At the proposed 

PEL, estimates of silicosis and nonmalignant respiratory disease mortality 

are 7 and 43 deaths per 1,000, 

respectively. As noted by Park et al. 

(2002), it is likely that silicosis as a 

cause of death is often misclassified as 

emphysema or chronic bronchitis; thus, 

Mannetje et al.’s selection of deaths may 

tend to underestimate the true risk of 

silicosis mortality, while Park et al.’s 

(2002) analysis would more fairly 

capture the total respiratory mortality 

risk from all non-malignant causes, 

including silicosis and COPD. 

OSHA also identified seven studies 

that quantitatively described 

relationships between exposure to 

respirable crystalline silica and silicosis 

morbidity, as diagnosed from chest 

radiography (i.e., chest x-rays or 

computerized tomography). Estimates of 

silicosis morbidity derived from these 

cohort studies range from 60 to 773 

cases per 1,000 workers for a 45-year 

exposure to the current general industry 

PEL, and approach unity for a 45-year 

exposure to the current construction/

shipyard PEL. Estimated risks of 

silicosis morbidity range from 20 to 170 

cases per 1,000 workers for a 45-year 

exposure to the proposed PEL, reflecting 

a substantial reduction in the risk 

associated with exposure to the current 

PELs. 

OSHA’s estimates of crystalline silicarelated renal disease mortality risk are 

derived from an analysis by Steenland 

et al. (2002), in which data from three 

cohort studies were pooled to derive a 

quantitative relationship between 

exposure to silica and the relative risk 

of end-stage renal disease mortality. The 

cohorts included workers in the U.S. 

gold mining, industrial sand, and 

granite industries. From this study, 

OSHA estimates that exposure to the 

current general industry and proposed 

PELs over a working life would result in 

a lifetime excess renal disease risk of 39 

and 32 deaths per 1,000 workers, 

respectively. For exposure to the current 

construction/shipyard PEL, OSHA 

estimates the excess lifetime risk to 

range from 52 to 63 deaths per 1,000 

workers. 

A Statement of the Objectives of, and 

Legal Basis for, the Proposed Rule 

The objective of the proposed rule is 

to reduce the numbers of fatalities and 

illnesses occurring among employees 

exposed to respirable crystalline silica 

in general industry, maritime, and 

construction sectors. This objective will 

be achieved by requiring employers to 

install engineering controls where 

appropriate and to provide employees 

with the equipment, respirators, 

training, exposure monitoring, medical 

surveillance, and other protective 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56411 

measures to perform their jobs safely. 

The legal basis for the rule is the 

responsibility given the U.S. 

Department of Labor through the 

Occupational Safety and Health Act of 

1970 (OSH Act). The OSH Act provides 

that, in promulgating health standards 

dealing with toxic materials or harmful 

physical agents, the Secretary ‘‘shall set 

the standard which most adequately 

assures, to the extent feasible, on the 

basis of the best available evidence that 

no employee will suffer material 

impairment of health or functional 

capacity even if such employee has 

regular exposure to the hazard dealt 

with by such standard for the period of 

his working life.’’ 29 U.S.C. Sec. 

655(b)(5). See Section II of this preamble 

for a more detailed discussion of the 

Secretary’s legal authority to promulgate 

standards. 

A Description of and Estimate of the 

Number of Small Entities To Which the 

Proposed Rule Will Apply 

OSHA has completed a preliminary 

analysis of the impacts associated with 

this proposal, including an analysis of 

the type and number of small entities to 

which the proposed rule would apply, 

as described above. In order to 

determine the number of small entities 

potentially affected by this rulemaking, 

OSHA used the definitions of small 

entities developed by the Small 

Business Administration (SBA) for each 

industry. 

OSHA estimates that approximately 

470,000 small business or government 

entities would be affected by the 

proposed standard. Within these small 

entities, roughly 1.3 million workers are 

exposed to crystalline silica and would 

be protected by the proposed standard. 

A breakdown, by industry, of the 

number of affected small entities is 

provided in Table III–3 in Chapter III of 

the PEA. 

OSHA estimates that approximately 

356,000 very small entities would be 

affected by the proposed standard. 

Within these very small entities, 

roughly 580,000 workers are exposed to 

crystalline silica and would be 

protected by the proposed standard. A 

breakdown, by industry, of the number 

of affected very small entities is 

provided in Table III–4 in Chapter III of 

the PEA. 

A Description of the Projected 

Reporting, Recordkeeping, and Other 

Compliance Requirements of the 

Proposed Rule 

Tables VIII–28 and VIII–29 show the 

average costs of the proposed standard 

by NAICS code and by compliance 

requirement for, respectively, small 

entities (classified as small by SBA) and 

very small entities (fewer than 20 

employees). For the average small entity 

in general industry and maritime, the 

estimated cost of the proposed rule 

would be about $2,103 annually, with 

engineering controls accounting for 67 

percent of the costs and exposure 

monitoring accounting for 23 percent of 

the costs. For the average small entity in 

construction, the estimate cost of the 

proposed rule would be about $798 

annually, with engineering controls 

accounting for 47 percent of the costs, 

exposure monitoring accounting for 17 

percent of the costs, and medical 

surveillance accounting for 15 percent 

of the costs. 

For the average very small entity in 

general industry and maritime, the 

estimate cost of the proposed rule 

would be about $616 annually, with 

engineering controls accounting for 55 

percent of the costs and exposure 

monitoring accounting for 33 percent of 

the costs. For the average very small 

entity in construction, the estimate cost 

of the proposed rule would be about 

$533 annually, with engineering 

controls accounting for 45 percent of the 

costs, exposure monitoring accounting 

for 16 percent of the costs, and medical 

surveillance accounting for 16 percent 

of the costs. 

Table VIII–30 shows the unit costs 

which form the basis for these cost 

estimates for the average small entity 

and very small entity. 

TABLE VIII–28—AVERAGE COSTS FOR SMALL ENTITIES AFFECTED BY THE PROPOSED SILICA STANDARD FOR GENERAL

INDUSTRY, MARITIME, AND CONSTRUCTION

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

324121 ..... Asphalt paving mixture and block manufacturing.$232 $4 $13 $1 $74 $1 $326 

324122 ..... Asphalt shingle and roofing materials .. 5,721 297 1,887 103 114 111 8,232 

325510 ..... Paint and coating manufacturing .......... 0 10 36 3 15 4 69 

327111 ..... Vitreous china plumbing fixtures & 

bathroom accessories manufacturing.

6,310 428 2,065 150 162 160 9,274 

327112 ..... Vitreous china, fine earthenware, & 

other pottery product manufacturing.

1,679 114 663 41 47 42 2,586 

327113 ..... Porcelain electrical supply mfg ............. 6,722 458 2,656 162 188 170 10,355 

327121 ..... Brick and structural clay mfg ................ 28,574 636 3,018 226 237 236 32,928 

327122 ..... Ceramic wall and floor tile mfg ............. 10,982 245 1,160 87 91 91 12,655 

327123 ..... Other structural clay product mfg ......... 10,554 235 1,115 83 87 87 12,162 

327124 ..... Clay refractory manufacturing .............. 1,325 92 653 33 81 34 2,218 

327125 ..... Nonclay refractory manufacturing ........ 1,964 136 802 48 110 51 3,110 

327211 ..... Flat glass manufacturing ...................... 4,068 160 520 56 50 60 4,913 

327212 ..... Other pressed and blown glass and 

glassware manufacturing.

889 34 110 12 11 13 1,068 

327213 ..... Glass container manufacturing ............. 2,004 76 248 27 24 29 2,408 

327320 ..... Ready-mixed concrete manufacturing .. 1,728 460 1,726 163 121 171 4,369 

327331 ..... Concrete block and brick mfg .............. 3,236 245 1,257 87 134 91 5,049 

327332 ..... Concrete pipe mfg ................................ 5,105 386 1,983 137 211 143 7,966 

327390 ..... Other concrete product mfg ................. 3,016 228 1,171 81 125 85 4,705 

327991 ..... Cut stone and stone product manufacturing.2,821 207 1,040 74 65 77 4,284 

327992 ..... Ground or treated mineral and earth 

manufacturing.

12,034 174 3,449 62 191 65 15,975 

327993 ..... Mineral wool manufacturing ................. 1,365 56 185 20 17 21 1,664 

327999 ..... All other misc. nonmetallic mineral 

product mfg.

2,222 168 863 60 92 62 3,467 

331111 ..... Iron and steel mills ............................... 604 34 138 12 11 13 812 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56412 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–28—AVERAGE COSTS FOR SMALL ENTITIES AFFECTED BY THE PROPOSED SILICA STANDARD FOR GENERAL

INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

331112 ..... Electrometallurgical ferroalloy product 

manufacturing.

514 29 118 10 10 11 692 

331210 ..... Iron and steel pipe and tube manufacturing from purchased steel.664 38 154 13 13 14 896 

331221 ..... Rolled steel shape manufacturing ........ 583 33 135 12 11 12 787 

331222 ..... Steel wire drawing ................................ 638 36 148 13 12 14 862 

331314 ..... Secondary smelting and alloying of 

aluminum.

577 33 133 11 11 12 777 

331423 ..... Secondary smelting, refining, and 

alloying of copper.

534 30 125 11 10 11 722 

331492 ..... Secondary smelting, refining, and 

alloying of nonferrous metal (except 

cu & al).

548 31 128 11 11 12 741 

331511 ..... Iron foundries ........................................ 9,143 522 2,777 185 200 194 13,021 

331512 ..... Steel investment foundries ................... 11,874 675 3,596 240 249 251 16,885 

331513 ..... Steel foundries (except investment) ..... 9,223 526 2,802 187 202 196 13,135 

331524 ..... Aluminum foundries (except die-casting).7,367 419 2,231 149 155 156 10,476 

331525 ..... Copper foundries (except die-casting) 4,563 260 1,382 92 96 96 6,489 

331528 ..... Other nonferrous foundries (except 

die-casting).

3,895 222 1,179 79 82 82 5,539 

332111 ..... Iron and steel forging ........................... 531 30 161 11 12 11 756 

332112 ..... Nonferrous forging ................................ 533 30 162 11 12 11 760 

332115 ..... Crown and closure manufacturing ....... 514 29 156 10 11 11 732 

332116 ..... Metal stamping ..................................... 533 30 162 11 12 11 759 

332117 ..... Powder metallurgy part manufacturing 535 31 163 11 12 11 762 

332211 ..... Cutlery and flatware (except precious) 

manufacturing.

518 30 157 10 11 11 738 

332212 ..... Hand and edge tool manufacturing ...... 542 31 165 11 12 12 772 

332213 ..... Saw blade and handsaw manufacturing.528 30 160 11 12 11 752 

332214 ..... Kitchen utensil, pot, and pan manufacturing.560 32 170 11 12 12 798 

332323 ..... Ornamental and architectural metal 

work.

524 20 102 7 11 8 673 

332439 ..... Other metal container manufacturing ... 550 31 167 11 12 12 784 

332510 ..... Hardware manufacturing ...................... 531 30 161 11 12 11 756 

332611 ..... Spring (heavy gauge) manufacturing ... 529 30 161 11 12 11 754 

332612 ..... Spring (light gauge) manufacturing ...... 585 33 178 12 13 12 834 

332618 ..... Other fabricated wire product manufacturing.537 31 163 11 12 11 765 

332710 ..... Machine shops ..................................... 518 30 157 10 11 11 738 

332812 ..... Metal coating and allied services ......... 843 33 165 12 18 12 1,083 

332911 ..... Industrial valve manufacturing .............. 528 30 160 11 12 11 752 

332912 ..... Fluid power valve and hose fitting 

manufacturing.

532 30 162 11 12 11 757 

332913 ..... Plumbing fixture fitting and trim manufacturing.528 30 160 11 12 11 752 

332919 ..... Other metal valve and pipe fitting manufacturing.536 31 163 11 12 11 764 

332991 ..... Ball and roller bearing manufacturing .. 545 31 131 11 11 12 741 

332996 ..... Fabricated pipe and pipe fitting manufacturing.529 30 161 11 12 11 754 

332997 ..... Industrial pattern manufacturing ........... 517 29 157 10 11 11 736 

332998 ..... Enameled iron and metal sanitary ware 

manufacturing.

484 23 97 8 10 9 630 

332999 ..... All other miscellaneous fabricated 

metal product manufacturing.

521 30 158 11 11 11 742 

333319 ..... Other commercial and service industry 

machinery manufacturing.

526 30 160 11 12 11 750 

333411 ..... Air purification equipment manufacturing.525 30 160 11 11 11 748 

333412 ..... Industrial and commercial fan and 

blower manufacturing.

555 32 169 11 12 12 791 

333414 ..... Heating equipment (except warm air 

furnaces) manufacturing.

520 30 158 11 11 11 741 

333511 ..... Industrial mold manufacturing .............. 522 30 159 11 11 11 743 

333512 ..... Machine tool (metal cutting types) 

manufacturing.

524 30 159 11 11 11 746 

333513 ..... Machine tool (metal forming types) 

manufacturing.

532 30 162 11 12 11 758 

333514 ..... Special die and tool, die set, jig, and 

fixture manufacturing.

522 30 158 11 11 11 743 

333515 ..... Cutting tool and machine tool accessory manufacturing.524 30 159 11 11 11 746 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56413 

TABLE VIII–28—AVERAGE COSTS FOR SMALL ENTITIES AFFECTED BY THE PROPOSED SILICA STANDARD FOR GENERAL

INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

333516 ..... Rolling mill machinery and equipment 

manufacturing.

522 30 159 11 11 11 744 

333518 ..... Other metalworking machinery manufacturing.537 31 163 11 12 11 765 

333612 ..... Speed changer, industrial high-speed 

drive, and gear manufacturing.

546 31 166 11 12 12 777 

333613 ..... Mechanical power transmission equipment manufacturing.529 30 161 11 12 11 754 

333911 ..... Pump and pumping equipment manufacturing.535 31 163 11 12 11 762 

333912 ..... Air and gas compressor manufacturing 532 30 162 11 12 11 758 

333991 ..... Power-driven handtool manufacturing .. 514 29 156 10 11 11 732 

333992 ..... Welding and soldering equipment manufacturing.523 30 159 11 11 11 745 

333993 ..... Packaging machinery manufacturing ... 521 30 158 11 11 11 742 

333994 ..... Industrial process furnace and oven 

manufacturing.

531 30 161 11 12 11 757 

333995 ..... Fluid power cylinder and actuator manufacturing.531 30 161 11 12 11 756 

333996 ..... Fluid power pump and motor manufacturing.542 31 165 11 12 11 772 

333997 ..... Scale and balance (except laboratory) 

manufacturing.

537 31 163 11 12 11 764 

333999 ..... All other miscellaneous general purpose machinery manufacturing.523 30 159 11 11 11 745 

334518 ..... Watch, clock, and part manufacturing .. 514 29 156 10 11 11 732 

335211 ..... Electric housewares and household 

fans.

523 20 76 7 9 8 643 

335221 ..... Household cooking appliance manufacturing.529 20 77 7 9 8 649 

335222 ..... Household refrigerator and home 

freezer manufacturing.

1,452 56 210 19 26 21 1,784 

335224 ..... Household laundry equipment manufacturing.1,461 56 212 19 26 21 1,795 

335228 ..... Other major household appliance manufacturing.523 20 101 7 11 8 671 

336111 ..... Automobile manufacturing .................... 1,309 75 297 25 23 28 1,757 

336112 ..... Light truck and utility vehicle manufacturing.4,789 273 1,085 92 86 102 6,425 

336120 ..... Heavy duty truck manufacturing ........... 1,211 69 275 23 22 26 1,626 

336211 ..... Motor vehicle body manufacturing ....... 579 33 137 11 11 12 784 

336212 ..... Truck trailer manufacturing ................... 525 30 160 11 11 11 748 

336213 ..... Motor home manufacturing .................. 792 45 181 15 15 17 1,064 

336311 ..... Carburetor, piston, piston ring, and 

valve manufacturing.

525 30 160 11 11 11 748 

336312 ..... Gasoline engine and engine parts 

manufacturing.

522 30 120 10 10 11 703 

336322 ..... Other motor vehicle electrical and electronic equipment manufacturing.524 30 121 10 10 11 706 

336330 ..... Motor vehicle steering and suspension 

components (except spring) manufacturing.

526 30 120 10 10 11 708 

336340 ..... Motor vehicle brake system manufacturing.527 30 121 10 10 11 710 

336350 ..... Motor vehicle transmission and power 

train parts manufacturing.

528 30 121 10 10 11 710 

336370 ..... Motor vehicle metal stamping .............. 556 32 169 11 12 12 792 

336399 ..... All other motor vehicle parts manufacturing.535 30 123 10 10 11 721 

336611 ..... Ship building and repair ....................... 13,685 0 718 692 47 75 15,217 

336612 ..... Boat building ......................................... 2,831 0 202 149 11 16 3,209 

336992 ..... Military armored vehicle, tank, and 

tank component manufacturing.

624 35 149 12 12 13 845 

337215 ..... Showcase, partition, shelving, and 

locker manufacturing.

527 30 160 11 12 11 751 

339114 ..... Dental equipment and supplies manufacturing.671 39 145 14 11 15 895 

339116 ..... Dental laboratories ............................... 12 7 130 3 44 3 199 

339911 ..... Jewelry (except costume) manufacturing.120 92 475 33 41 34 795 

339913 ..... Jewelers’ materials and lapidary work 

manufacturing.

151 115 596 41 51 43 997 

339914 ..... Costume jewelry and novelty manufacturing.87 44 229 16 19 16 412 

339950 ..... Sign manufacturing ............................... 465 20 107 7 11 8 618 

423840 ..... Industrial supplies, wholesalers ............ 313 29 257 10 15 11 636 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56414 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–28—AVERAGE COSTS FOR SMALL ENTITIES AFFECTED BY THE PROPOSED SILICA STANDARD FOR GENERAL

INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

482110 ..... Rail transportation ................................ ...................... ...................... ...................... ...................... ...................... ...................... ......................

621210 ..... Dental offices ........................................ 3 2 32 1 11 1 50 

Total—General Industry and Maritime 1,399 93 483 46 46 36 2,103 

236100 ..... Residential Building Construction ......... 264 43 34 37 27 15 419 

236200 ..... Nonresidential Building Construction ... 234 104 67 89 66 14 575 

237100 ..... Utility System Construction .................. 978 89 172 78 185 30 1,531 

237200 ..... Land Subdivision .................................. 104 9 25 8 30 3 180 

237300 ..... Highway, Street, and Bridge Construction.692 109 179 95 227 26 1,329 

237900 ..... Other Heavy and Civil Engineering 

Construction.

592 60 134 52 175 18 1,032 

238100 ..... Foundation, Structure, and Building 

Exterior Contractors.

401 359 113 307 91 49 1,319 

238200 ..... Building Equipment Contractors ........... 156 18 21 16 27 7 244 

238300 ..... Building Finishing Contractors .............. 289 24 23 50 27 9 421 

238900 ..... Other Specialty Trade Contractors ....... 460 43 65 52 79 30 729 

999000 ..... State and Local Governments [c] ......... 108 16 31 14 43 11 222 

Total—Construction .............................. 375 132 72 122 71 26 798 

Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on ERG (2013). 

TABLE VIII–29—AVERAGE COSTS FOR VERY SMALL ENTITIES (<20 EMPLOYEES) AFFECTED BY THE PROPOSED SILICA

STANDARD FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

324121 ..... Asphalt paving mixture and block manufacturing.$74 $1 $5 $0 $26 $0 $107 

324122 ..... Asphalt shingle and roofing materials .. 914 48 476 17 23 18 1,496 

325510 ..... Paint and coating manufacturing .......... 0 7 33 3 13 3 58 

327111 ..... Vitreous china plumbing fixtures & 

bathroom accessories manufacturing.

851 58 422 21 26 22 1,400 

327112 ..... Vitreous china, fine earthenware, & 

other pottery product manufacturing.

705 48 349 17 22 18 1,160 

327113 ..... Porcelain electrical supply mfg ............. 851 58 422 21 26 22 1,400 

327121 ..... Brick and structural clay mfg ................ 2,096 47 277 17 19 17 2,474 

327122 ..... Ceramic wall and floor tile mfg ............. 2,385 53 316 19 22 20 2,815 

327123 ..... Other structural clay product mfg ......... 2,277 51 301 18 21 19 2,687 

327124 ..... Clay refractory manufacturing .............. 301 21 186 8 20 8 543 

327125 ..... Nonclay refractory manufacturing ........ 471 33 291 12 32 12 852 

327211 ..... Flat glass manufacturing ...................... 842 34 163 12 12 12 1,075 

327212 ..... Other pressed and blown glass and 

glassware manufacturing.

873 34 164 12 12 12 1,107 

327213 ..... Glass container manufacturing ............. 873 34 164 12 12 12 1,107 

327320 ..... Ready-mixed concrete manufacturing .. 475 127 595 46 37 47 1,328 

327331 ..... Concrete block and brick mfg .............. 966 74 470 27 44 27 1,608 

327332 ..... Concrete pipe mfg ................................ 1,046 80 509 29 48 29 1,741 

327390 ..... Other concrete product mfg ................. 854 65 416 23 39 24 1,422 

327991 ..... Cut stone and stone product manufacturing.1,158 86 535 31 30 32 1,872 

327992 ..... Ground or treated mineral and earth 

manufacturing.

3,564 52 1,280 19 63 19 4,997 

327993 ..... Mineral wool manufacturing ................. 823 34 166 12 12 13 1,061 

327999 ..... All other misc. nonmetallic mineral 

product mfg.

797 61 388 22 37 22 1,327 

331111 ..... Iron and steel mills ............................... 517 30 197 11 13 11 777 

331112 ..... Electrometallurgical ferroalloy product 

manufacturing.

0 0 0 0 0 0 0 

331210 ..... Iron and steel pipe and tube manufacturing from purchased steel.514 30 196 11 12 11 774 

331221 ..... Rolled steel shape manufacturing ........ 514 30 196 11 12 11 774 

331222 ..... Steel wire drawing ................................ 514 30 196 11 12 11 774 

331314 ..... Secondary smelting and alloying of 

aluminum.

514 30 196 11 12 11 774 

331423 ..... Secondary smelting, refining, and 

alloying of copper.

0 0 0 0 0 0 0 

331492 ..... Secondary smelting, refining, and 

alloying of nonferrous metal (except 

cu & al).

514 30 196 11 12 11 774 

331511 ..... Iron foundries ........................................ 1,093 63 416 23 26 23 1,644 

331512 ..... Steel investment foundries ................... 1,181 68 448 24 28 25 1,774 

331513 ..... Steel foundries (except investment) ..... 1,060 61 404 22 26 22 1,595 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56415 

TABLE VIII–29—AVERAGE COSTS FOR VERY SMALL ENTITIES (<20 EMPLOYEES) AFFECTED BY THE PROPOSED SILICA

STANDARD FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

331524 ..... Aluminum foundries (except die-casting).1,425 82 541 29 33 30 2,141 

331525 ..... Copper foundries (except die-casting) 1,503 86 570 31 35 32 2,257 

331528 ..... Other nonferrous foundries (except 

die-casting).

1,401 80 532 29 33 30 2,104 

332111 ..... Iron and steel forging ........................... 514 30 196 11 12 11 774 

332112 ..... Nonferrous forging ................................ 514 30 196 11 12 11 774 

332115 ..... Crown and closure manufacturing ....... 514 30 196 11 12 11 774 

332116 ..... Metal stamping ..................................... 515 30 196 11 12 11 775 

332117 ..... Powder metallurgy part manufacturing 514 30 196 11 12 11 774 

332211 ..... Cutlery and flatware (except precious) 

manufacturing.

514 30 196 11 12 11 774 

332212 ..... Hand and edge tool manufacturing ...... 514 30 196 11 12 11 774 

332213 ..... Saw blade and handsaw manufacturing.514 30 196 11 12 11 774 

332214 ..... Kitchen utensil, pot, and pan manufacturing.0 0 0 0 0 0 0 

332323 ..... Ornamental and architectural metal 

work.

520 20 127 7 12 8 694 

332439 ..... Other metal container manufacturing ... 524 30 199 11 13 11 788 

332510 ..... Hardware manufacturing ...................... 517 30 197 11 13 11 777 

332611 ..... Spring (heavy gauge) manufacturing ... 523 30 199 11 13 11 786 

332612 ..... Spring (light gauge) manufacturing ...... 514 30 196 11 12 11 774 

332618 ..... Other fabricated wire product manufacturing.514 30 196 11 12 11 774 

332710 ..... Machine shops ..................................... 515 30 196 11 12 11 774 

332812 ..... Metal coating and allied services ......... 519 20 127 7 12 8 694 

332911 ..... Industrial valve manufacturing .............. 514 30 196 11 12 11 774 

332912 ..... Fluid power valve and hose fitting 

manufacturing.

514 30 196 11 12 11 774 

332913 ..... Plumbing fixture fitting and trim manufacturing.514 30 196 11 12 11 774 

332919 ..... Other metal valve and pipe fitting manufacturing.519 30 198 11 13 11 781 

332991 ..... Ball and roller bearing manufacturing .. 514 30 196 11 12 11 774 

332996 ..... Fabricated pipe and pipe fitting manufacturing.514 30 196 11 12 11 774 

332997 ..... Industrial pattern manufacturing ........... 514 30 196 11 12 11 774 

332998 ..... Enameled iron and metal sanitary ware 

manufacturing.

484 23 153 8 12 9 690 

332999 ..... All other miscellaneous fabricated 

metal product manufacturing.

514 30 196 11 12 11 774 

333319 ..... Other commercial and service industry 

machinery manufacturing.

514 30 196 11 12 11 774 

333411 ..... Air purification equipment manufacturing.514 30 196 11 12 11 774 

333412 ..... Industrial and commercial fan and 

blower manufacturing.

514 30 196 11 12 11 774 

333414 ..... Heating equipment (except warm air 

furnaces) manufacturing.

517 30 197 11 13 11 777 

333511 ..... Industrial mold manufacturing .............. 515 30 196 11 12 11 774 

333512 ..... Machine tool (metal cutting types) 

manufacturing.

516 30 196 11 13 11 776 

333513 ..... Machine tool (metal forming types) 

manufacturing.

514 30 196 11 12 11 774 

333514 ..... Special die and tool, die set, jig, and 

fixture manufacturing.

515 30 196 11 12 11 774 

333515 ..... Cutting tool and machine tool accessory manufacturing.515 30 196 11 12 11 775 

333516 ..... Rolling mill machinery and equipment 

manufacturing.

514 30 196 11 12 11 774 

333518 ..... Other metalworking machinery manufacturing.514 30 196 11 12 11 774 

333612 ..... Speed changer, industrial high-speed 

drive, and gear manufacturing.

514 30 196 11 12 11 774 

333613 ..... Mechanical power transmission equipment manufacturing.514 30 196 11 12 11 774 

333911 ..... Pump and pumping equipment manufacturing.514 30 196 11 12 11 774 

333912 ..... Air and gas compressor manufacturing 514 30 196 11 12 11 774 

333991 ..... Power-driven handtool manufacturing .. 514 30 196 11 12 11 774 

333992 ..... Welding and soldering equipment manufacturing.514 30 196 11 12 11 774 

333993 ..... Packaging machinery manufacturing ... 514 30 196 11 12 11 774 

333994 ..... Industrial process furnace and oven 

manufacturing.

514 30 196 11 12 11 774 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56416 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–29—AVERAGE COSTS FOR VERY SMALL ENTITIES (<20 EMPLOYEES) AFFECTED BY THE PROPOSED SILICA

STANDARD FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

333995 ..... Fluid power cylinder and actuator manufacturing.514 30 196 11 12 11 774 

333996 ..... Fluid power pump and motor manufacturing.514 30 196 11 12 11 774 

333997 ..... Scale and balance (except laboratory) 

manufacturing.

514 30 196 11 12 11 774 

333999 ..... All other miscellaneous general purpose machinery manufacturing.514 30 196 11 12 11 774 

334518 ..... Watch, clock, and part manufacturing .. 514 30 196 11 12 11 774 

335211 ..... Electric housewares and household 

fans.

0 0 0 0 0 0 0 

335221 ..... Household cooking appliance manufacturing.523 20 127 7 12 8 698 

335222 ..... Household refrigerator and home 

freezer manufacturing.

0 0 0 0 0 0 0 

335224 ..... Household laundry equipment manufacturing.0 0 0 0 0 0 0 

335228 ..... Other major household appliance manufacturing.0 0 0 0 0 0 0 

336111 ..... Automobile manufacturing .................... 514 30 196 11 12 11 774 

336112 ..... Light truck and utility vehicle manufacturing.514 30 196 11 12 11 774 

336120 ..... Heavy duty truck manufacturing ........... 514 30 196 11 12 11 774 

336211 ..... Motor vehicle body manufacturing ....... 514 30 196 11 12 11 774 

336212 ..... Truck trailer manufacturing ................... 514 30 196 11 12 11 774 

336213 ..... Motor home manufacturing .................. 514 30 196 11 12 11 774 

336311 ..... Carburetor, piston, piston ring, and 

valve manufacturing.

514 30 196 11 12 11 774 

336312 ..... Gasoline engine and engine parts 

manufacturing.

514 30 196 11 12 11 774 

336322 ..... Other motor vehicle electrical and electronic equipment manufacturing.514 30 196 11 12 11 774 

336330 ..... Motor vehicle steering and suspension 

components (except spring) manufacturing.

514 30 196 11 12 11 774 

336340 ..... Motor vehicle brake system manufacturing.514 30 196 11 12 11 774 

336350 ..... Motor vehicle transmission and power 

train parts manufacturing.

514 30 196 11 12 11 774 

336370 ..... Motor vehicle metal stamping .............. 517 30 197 11 13 11 778 

336399 ..... All other motor vehicle parts manufacturing.514 30 196 11 12 11 774 

336611 ..... Ship building and repair ....................... 2,820 0 253 151 13 16 3,252 

336612 ..... Boat building ......................................... 2,816 0 252 151 12 15 3,247 

336992 ..... Military armored vehicle, tank, and 

tank component manufacturing.

0 0 0 0 0 0 0 

337215 ..... Showcase, partition, shelving, and 

locker manufacturing.

514 30 196 11 12 11 774 

339114 ..... Dental equipment and supplies manufacturing.663 39 180 14 12 14 922 

339116 ..... Dental laboratories ............................... 8 5 107 2 32 2 156 

339911 ..... Jewelry (except costume) manufacturing.45 35 225 13 17 13 348 

339913 ..... Jewelers’ materials and lapidary work 

manufacturing.

52 40 256 14 19 15 397 

339914 ..... Costume jewelry and novelty manufacturing.50 26 166 9 12 10 274 

339950 ..... Sign manufacturing ............................... 459 20 132 7 12 7 639 

423840 ..... Industrial supplies, wholesalers ............ 262 24 215 9 13 9 531 

482110 ..... Rail transportation ................................

621210 ..... Dental offices ........................................ 3 2 32 1 11 1 49 

Total—General Industry and Maritime 337 29 205 12 23 11 616 

236100 ..... Residential Building Construction ......... 264 43 42 38 30 15 432 

236200 ..... Nonresidential Building Construction ... 117 52 42 46 37 7 301 

237100 ..... Utility System Construction .................. 326 30 71 27 69 10 532 

237200 ..... Land Subdivision .................................. 104 9 25 8 30 3 180 

237300 ..... Highway, Street, and Bridge Construction.275 44 89 39 102 10 559 

237900 ..... Other Heavy and Civil Engineering 

Construction.

202 20 57 18 67 6 372 

238100 ..... Foundation, Structure, and Building 

Exterior Contractors.

228 204 80 180 58 28 778 

238200 ..... Building Equipment Contractors ........... 156 18 26 16 30 7 253 

238300 ..... Building Finishing Contractors .............. 289 24 28 51 30 9 431 

238900 ..... Other Specialty Trade Contractors ....... 276 26 49 32 53 18 454 

999000 ..... State and Local Governments [c] ......... N/A N/A N/A N/A N/A N/A N/A 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56417 

TABLE VIII–29—AVERAGE COSTS FOR VERY SMALL ENTITIES (<20 EMPLOYEES) AFFECTED BY THE PROPOSED SILICA

STANDARD FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

[2009 dollars] 

NAICS Industry 

Engineering 

controls (includes abrasive blasting) 

Respirators Exposure 

monitoring 

Medical surveillance Training 

Regulated 

areas or access control Total 

Total—Construction .............................. 242 87 56 83 49 17 533 

Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on ERG (2013). 

TABLE VIII–30—SOURCE INFORMATION FOR THE UNIT COST ESTIMATES USED IN OSHA’S PRELIMINARY COST ANALYSIS

FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION

Control [a] Description Ventilation 

airflow (cfm) Capital cost [b] Operating cost Annualized capital cost Comment or source 

Saw enclosure ............ 8′ x 8′ x 8′ wood/plastic.N/A $487 .70 $48 .77 $118.95 Fabrication costs estimated by ERG, assuming in-plant 

work. Five-year life. 

Cab enclosures .......... Enclosed cabs ............ N/A 15,164 .82 5,307 .69 3,698.56 ERG estimate based 

on vendor interviews. 

LEV for hand held 

grinders.

Shrouds + vacuum ..... N/A 1,671 .63 585 .07 407.70 Vacuum plus shroud 

adapter (http://www.

proventilation.com/

products/productDetail.asp?id=15); 35% 

for maintenance and 

operating costs. 

Upgraded abrasive 

blast cabinet.

Improved maintenance 

and purchases for 

some.

N/A 4,666 .10 1,000 .00 664.35 Assumes add. maintenance (of up to 

$2,000) or new cabinets ($8,000) (Norton, 2003). 

Improved spray booth 

for pottery.

Maintenance time & 

materials.

N/A 116 .65 114 .68 231.33 Annual: $100 materials plus 4 hours 

maintenance time. 

Improved LEV for ceramics spray booth.Increased air flow; per 

cfm.

N/A 3 .21 0 .88 3.21 25% of installed CFM 

price. 

Exhaust for saw, cut 

stone industry.

Based on saw LEV 

(e.g., pg. 10–158, 

159, 160, ACGIH, 

2001).

450 5,774 .30 1,577 .35 822.13 ERG based on typical 

saw cfm requirements. 

LEV for hand chipping 

in cut stone.

Granite cutting and finishing; (pg. 10–94, 

ACGIH, 2001).

600 7,699 .06 2,103 .14 1,096.17 ERG estimate of cfm 

requirements. 

Exhaust trimming machine.Based on abrasive 

cut-off saw; (pg. 10– 

134) (ACGIH, 2001).

500 6,415 .89 1,752 .61 913.48 Opening of 2 sq ft assumed, with 250 

cfm/sq.ft. 

Bag opening ............... Bag opening station; 

(pg. 10–19, ACGIH, 

2001).

1,513 19,414 .48 5,303 .41 2,764.18 3.5′ x 1.5′ opening; 

with ventilated bag 

crusher (200 cfm). 

Conveyor ventilation ... Conveyor belt ventilation; (pg. 10–70, 

ACGIH, 2001).

700 8,982 .24 2,453 .66 1,278.87 Per take-off point, 2′ 

wide belt. 

Bucket elevator ventilation.Bucket elevator ventilation (pg. 10–68; 

ACGIH, 2001).

1,600 20,530 .84 5,608 .36 2,923.13 2′ x 3′ x 30′ casing; 4 

take-offs @250 cfm; 

100 cfm per sq ft of 

cross section. 

Bin and hopper ventilation.Bin and hopper ventilation (pg. 10–69; 

ACGIH, 2001).

1,050 13,473 .36 3,680 .49 1,918.30 350 cfm per ft2; 3’ belt 

width. 

Screen ventilation ....... Ventilated screen (pg. 

10–173, ACGIH, 

2001).

1,200 15,398 .13 4,206 .27 2,192.35 4′ x 6′ screen; 50 cfm 

per ft2. 

Batch operator 

workstation.

Bin & hopper ventilation for unvented 

mixers (pg. 10–69, 

ACGIH, 2001).

1,050 13,473 .36 3,680 .49 1,918.30 ERG estimate of cfm 

requirements. 

LEV for hand grinding 

operator (pottery).

Hand grinding bench 

(pg. 10–135, 

ACGIH, 2001).

3,750 48,119 .16 13,144 .60 6,851.09 ERG estimate of cfm 

requirements. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56418 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–30—SOURCE INFORMATION FOR THE UNIT COST ESTIMATES USED IN OSHA’S PRELIMINARY COST ANALYSIS

FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

Control [a] Description Ventilation 

airflow (cfm) Capital cost [b] Operating cost Annualized capital cost Comment or source 

LEV, mixer and muller 

hood.

Mixer & muller hood 

(pg. 10–87, ACGIH, 

2001).

1,050 13,473 .36 3,680 .49 1,918.30 ERG estimate of cfm 

requirements. 

LEV for bag filling stations.Bag filling station (pg. 

10–15, ACGIH, 

2001).

1,500 19,247 .66 5,257 .84 2,740.43 Includes costs for air 

shower. 

Installed manual spray 

mister.

Manual controls, system covers 100 ft of 

conveyor.

N/A 10,207 .09 1,020 .71 1,453.26 National Environmental Services 

Company (Kestner, 

2003). 

Install cleaning hoses, 

reslope floor, drainage.

Plumbing for hose installations, floor resloping and troughs.N/A 36,412 .40 3,258 .87 5,184.31 ERG estimate. Includes cost of water 

and labor time. 

Shakeout conveyor 

enclosure.

Ventilated shakeout 

conveyor enclosure.

10,000 128,317 .75 35,052 .26 18,269.56 ERG estimate. 

Shakeout side-draft 

ventilation.

Shakeout double sidedraft table (pg. 10– 

23, ACGIH, 2001).

28,800 369,555 .11 100,950 .52 52,616.33 ERG estimate of cfm 

requirements. 

Shakeout enclosing 

hood.

Ventilated enclosing 

hood (pg. 10–23, 

ACGIH, 2001); 4′ x 

4′ openings.

7,040 90,335 .69 24,676 .79 12,861.77 ERG estimate of 

opening size required. 

Small knockout table .. Portable grinding table 

pg. 10–136), 

ACGIH, 2001), 3′ x 

3′ opening.

1,350 17,322 .90 4,732 .06 2,466.39 ERG estimate of 

opening size required. 

Large knockout table .. Hand grinding table 

pg. 10–135), 

ACGIH, 2001), 4′ x 

6′ surface.

4,800 61,592 .52 16,825 .09 8,769.39 ERG estimate of 

bench surface area. 

Ventilated abrasive 

cutoff saw.

Ventilated cut-off saw 

(pg. 10–134, 

ACGIH, 2001, 2′ x 

3′ opening.

1,500 19,247 .66 5,257 .84 2,740.43 ERG estimate of 

opening size required. 

Hand grinding bench 

(foundry).

Bench with LEV (pg. 

10–135, ACGIH, 

2001); 3′ x 5′.

3,750 48,119 .16 13,144 .60 6,851.09 ERG estimate of cfm 

requirements; 250 

cfm/sq. ft. 

Forming operator 

bench (pottery).

Bench with LEV (pg. 

10–149, ACGIH, 

2001), 3′ x 4′.

1,400 17,964 .48 4,907 .32 2,557.74 ERG estimate of cfm 

requirements; 125 

cfm per linear foot. 

Hand grinding bench 

(pottery).

Bench with LEV (pg. 

10–135, ACGIH, 

2001); 3′ x 4′.

2,400 30,796 .26 8,412 .54 4,384.69 ERG estimate of cfm 

requirements; 200 

cfm/sq. ft. 

Hand tool hardware .... Retrofit suction attachment.200 464 .21 701 .05 66.09 ERG estimate of cfm 

requirements. 

Clean air island .......... Clean air supplied directly to worker.2,500 32,079 .44 8,763 .07 4,567.39 ERG estimate of cfm 

requirements; 125 

cfm/sq. ft. for 20 

square feet. 

Water fed chipping 

equipment drum 

cleaning.

Shop-built water feed 

equipment.

N/A 116 .65 0 .00 116.65 ERG estimate. $100 in 

annual costs. 

Ventilation for drum 

cleaning.

Ventilation blower and 

ducting.

N/A 792 .74 198 .18 193.34 Electric blower (1,277 

cfm) and 25 ft. of 

duct. Northern Safety Co. (p. 193). 

Control room .............. 10′ x 10′ ventilated 

control room with 

HEPA filter.

200 19,556 .79 701 .05 2,784.45 ERG estimate based 

on RSMeans 

(2003), ACGIH 

(2001). 

Control room improvement.Repair and improve 

control room enclosure.

N/A 2,240 .00 N/A 318.93 ERG estimate. Assumes repairs are 

20% of new control 

room cost. 

Improved bag valves .. Bags with extended 

polyethylene valve, 

incremental cost per 

bag.

N/A 0 .01 N/A N/A Cecala et. al., (1986). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56419 

TABLE VIII–30—SOURCE INFORMATION FOR THE UNIT COST ESTIMATES USED IN OSHA’S PRELIMINARY COST ANALYSIS

FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

Control [a] Description Ventilation 

airflow (cfm) Capital cost [b] Operating cost Annualized 

capital cost Comment or source 

Dust suppressants ..... Kleen Products 50 lb 

poly bag green 

sweeping compound.

N/A N/A 634 .54 0.00 0.28/lb, 2 lbs/day; 5 

minutes/day 

(www.fastenal.com). 

HEPA vacuum for 

housekeeping.

NILFISK VT60 wet/dry 

hepa vac, 15 gal.

N/A 3,494 .85 511 .20 852.36 Nilfisk, HEPA vacuum 

(http://www.sylvane.

com/nilfisk.html). 

HEPA vacuum for 

housekeeping.

NILFISK, large capacity.N/A 7,699 .06 988 .90 1,877.73 Nilfisk, HEPA vacuum 

(McCarthy, 2003). 

Yard dust suppression 100 ft, 1’’ contractor 

hose and nozzle.

N/A 204 .14 0 .00 112.91 Contactor hose and 

nozzle; 2 year life; 

(www.pwmall.com). 

Wet methods to clean 

concrete mixing 

equip..

10 mins per day per 

operator.

N/A 0 .00 916 .82 0.00 10 mins per day per 

mixer operator. 

HEPA vacuum substitute for compressed air.Incremental time to remove dust by vacuum.N/A N/A 494 .54 0.00 5 min per day per affected worker. 

Spray system for wet 

concrete finishing.

Shop-built sprayer 

system.

N/A 204 .67 20 .47 113.20 Assumes $100 in materials and 4 hours 

to fabricate. Also 

10% for maintenance. 

Substitute alt., non-silica, blasting media.Alternative media estimated to cost 22 

percent more.

N/A 0 .00 33,646 .00 0.00 Based on 212,000 

square feet of coverage per year per 

crew. 

Abrasive blasting cost 

per square foot (dry 

blasting).

125 blasting days per 

year.

N/A N/A 2 .00 N/A ERG estimate based 

on RSMeans 

(2009). 

Half-mask, non-powered, air-purifying 

respirator.

Unit cost includes expenses for accessories, training, fit 

testing, and cleaning.

N/A N/A 570 .13 N/A 

Full-face nonpowered 

air-purifying respirator.

Unit cost includes expenses for accessories, training, fit 

testing, and cleaning.

N/A N/A 637 .94 N/A 

Half-face respirator 

(construction).

Unit cost includes expenses for accessories, training, fit 

testing, and cleaning.

N/A N/A 468 .74 N/A 

Industrial Hygiene 

Fees/personal 

breathing zone.

Consulting IH technician—rate per sample. Assumes IH 

rate of $500 per day 

and samples per 

day of 2, 6, and 8 

for small, medium, 

and large establishments, respectively.

N/A N/A 500 N/A 

Exposure assessment 

lab fees and shipping cost.

..................................... N/A N/A 133 .38 N/A Lab fees (EMSL Laboratory, 2000) and 

OSHA estimates. Inflated to 2009 values. 

Physical examination 

by knowledgeable 

Health Care Practitioner.

Evaluation and office 

consultation including detailed examination.

N/A N/A 100 .00 N/A ERG, 2013. 

Chest X-ray ................ Tri-annual radiologic 

examination, chest; 

stereo, frontal. 

Costs include consultation and written 

report.

N/A N/A 79 .61 N/A 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56420 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–30—SOURCE INFORMATION FOR THE UNIT COST ESTIMATES USED IN OSHA’S PRELIMINARY COST ANALYSIS

FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

Control [a] Description Ventilation 

airflow (cfm) Capital cost [b] Operating cost Annualized capital cost Comment or source 

Pulmonary function 

test.

Tri-annual spirometry, 

including graphic 

record, total and 

timed vital capacity, 

expiratory flow rate 

measurements(s), 

and/or maximal voluntary ventilation.

N/A N/A 54 .69 N/A 

Examination by a pulmonary specialist [c].Office consultation and 

evaluation by a pulmonary specialist.

N/A N/A 190 .28 N/A 

Training instructor cost 

per hour.

..................................... N/A N/A 34 .09 N/A Based on supervisor 

wage, adjusted for 

fringe benefits (BLS, 

2008, updated to 

2009 dollars). 

Training materials for 

class per attendee.

Estimated cost of $2 

per worker for the 

training/reading materials.

N/A N/A 2 .00 N/A 

Value of worker time 

spent in class.

..................................... N/A N/A 17 .94 N/A Based on worker 

wage, adjusted for 

fringe benefits (BLS, 

2008, updated to 

2009 dollars). 

Cost—disposable particulate respirator 

(N95).

1.00 per respirator per 

day, typical cost for 

N95 disposable respirator.

N/A N/A 1 .00 N/A Lab Safety Supply, 

2010. 

Disposable clothing .... Per suit, daily clothing 

costs for 10% of 

workers.

N/A N/A 5 .50 N/A Lab Safety Supply, 

2010. 

Hazard tape ................ Per regulated area for 

annual set-up (300 

ft).

N/A N/A 5 .80 N/A Lab Safety Supply, 

2010. 

Warning signs (6 per 

regulated area).

25.30 per sign ............ N/A N/A 151 .80 N/A Lab Safety Supply, 

2010. 

Wet kit, with water 

tank.

..................................... N/A 226 .73 [d] 0 .18 125.40 Contractors Direct 

(2009); Berland 

House of Tools 

(2009); mytoolstore 

(2009). 

Dust shrouds: grinder ..................................... N/A 97 .33 [d] 0 .14 97.33 Contractors Direct 

(2009); Berland 

House of Tools 

(2009); Dust-Buddy 

(2009); Martin 

(2008). 

Water tank, portable 

(unspecified capacity).

..................................... N/A N/A [e] 15 .50 N/A RSMeans—based on 

monthly rental cost. 

Water tank, small capacity (hand pressurized)...................................... N/A 73 .87 [d] 0 .11 79.04 Contractors Direct 

(2009); mytoolstore 

(2009). 

Hose (water), 20′, 2′′ 

diameter.

..................................... N/A N/A [e] 1 .65 N/A RSMeans—based on 

monthly cost. 

Custom water spray 

nozzle and attachments.

..................................... N/A 363 [d] 0 .54 388.68 New Jersey Laborers’ 

Health and Safety 

Fund (2007). 

Hose (water), 200′, 2′′ 

diameter.

..................................... N/A N/A [e] 16 .45 N/A RSMeans—based on 

monthly rental cost. 

Vacuum, 10–15 gal 

with HEPA.

..................................... N/A 725 [d] 0 .56 400.99 ICS (2009); Dust Collection (2009); 

EDCO (2009); CS 

Unitec (2009). 

Vacuum, large capacity with HEPA...................................... N/A 2,108 [d] 1 .63 1,165.92 ICS (2009); EDCO 

(2009); Aramsco 

(2009). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56421 

TABLE VIII–30—SOURCE INFORMATION FOR THE UNIT COST ESTIMATES USED IN OSHA’S PRELIMINARY COST ANALYSIS

FOR GENERAL INDUSTRY, MARITIME, AND CONSTRUCTION—Continued 

Control [a] Description Ventilation 

airflow (cfm) Capital cost [b] Operating cost Annualized 

capital cost Comment or source 

Dust extraction kit (rotary hammers)...................................... N/A 215 [d] 0 .30 214.81 Grainger (2009); 

mytoolstore (2009); 

Toolmart (2009). 

Dust control/quarry 

drill.

..................................... N/A N/A [e] 17 .33 N/A RSMeans Heavy Construction Cost Data 

(2008). 

Dustless drywall sander...................................... N/A 133 [d] 0 .19 133.33 Home Depot (2009); 

LSS (2009); Dustless Tech (2009). 

Cab enclosure/w ventilation and air conditioning...................................... N/A 13,000 [d] 2 .59 1,850.91 Estimates from equipment suppliers and 

retrofitters. 

Foam dust suppression system...................................... N/A 14,550 [e] 162 .07 2,071.59 Midyette (2003). 

Water tank, engine 

driven discharge, 

5000 gal..

..................................... N/A N/A [d] 121 .50 N/A RSMeans (2008)— 

based on monthly 

rental cost. 

Tunnel dust suppression system supplement...................................... N/A 7,928 [e] 2 .71 1,933.47 Raring (2003). 

Training instructor cost 

per hour (Construction).

..................................... N/A N/A 43 .12 N/A Based on supervisor 

wage, adjusted for 

fringe benefits (BLS, 

2008, updated to 

2009 dollars). 

Value of worker time 

spent in class (Construction).

..................................... N/A N/A 22 .22 N/A Based on worker 

wage, adjusted for 

fringe benefits (BLS, 

2008, updated to 

2009 dollars). 

Warning signs (3 per 

regulated area) 

(Construction).

25.30 per sign ............ N/A N/A 75 .90 N/A Lab Safety Supply, 

2010. 

Per-worker costs for 

written access control plan or regulated area setup implementation (Construction).

Weighted average annual cost per worker; Applies to workers with exposures 

above the PEL.

175 .56 

[a]For local exhaust ventilation (LEV), maintenance, and conveyor covers, OSHA applied the following estimates: 

LEV: capital cost = $12.83 per cfm; operating cost = $3.51 per cfm; annualized capital cost = $1.83 per cfm; based on current energy prices 

and the estimates of consultants to ERG (2013). 

Maintenance: estimated as 10% of capital cost. 

Conveyor Covers: estimated as $17.10 per linear foot for 100 ft. (Landola, 2003); capital cost = $19.95 per linear ft., including all hardware; 

annualized capital cost = $2.84 per linear ft. 

[b]Adjusted from 2003 price levels using an inflation factor of 1.166, calculated as the ratio of average annual GDP Implicit Price Deflator for 

2009 and 2003. 

[c] Mean expense per office-based physician visit to a pulmonary specialist for diagnosis and treatment, based on data from the 2004 Medical 

Expenditure Panel Survey. Inflated to 2009 dollars using the consumer price inflator for medical services. 

Costs for physical exams and tests, chest X-ray, and pulmonary tests are direct medical costs used in bundling services under Medicare 

(Intellimed International, 2003). Costs are inflated by 30% to eliminate the effect of Medicare discounts that are unlikely to apply to occupational 

medicine environments. 

[d] Daily maintenance and operating cost. 

[e] Daily equipment costs derived from RS Means (2008) monthly rental rates, which include maintenance and operating costs. 

Source: U.S. Dept. of Labor, OSHA, Directorate of Standards and Guidance, Office of Regulatory Analysis, based on ERG (2013). 

Federal Rules Which May Duplicate, 

Overlap, or Conflict With the Proposed 

Rule. 

OSHA has not identified any other 

Federal rules which may duplicate, 

overlap, or conflict with the proposal, 

and requests comments from the public 

regarding this issue. 

1. Alternatives to the Proposed Rule 

which Accomplish the Stated Objectives 

of Applicable Statutes and which 

Minimize any Significant Economic 

Impact of the Proposed Rule on Small 

Entities 

This section first discusses several 

provisions in the proposed standard that 

OSHA has adopted or modified based 

on comments from small entity 

representatives (SERs) during the 

SBREFA Panel process or on 

recommendations made by the SBREFA 

Panel as potentially alleviating impacts 

on small entities. Then, the Agency 

presents various regulatory alternatives 

to the proposed OSHA silica standard. 

a. Elements of Proposed Rule To Reduce 

Impacts on Small Entities 

The SBREFA Panel was concerned 

that changing work conditions in the 

construction industry would make it 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56422 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

difficult to apply some of the provisions 

that OSHA suggested at the time of the 

Panel. OSHA has preliminarily decided 

to change its approach in this sector. 

OSHA is proposing two separate 

standards, one for general industry and 

maritime and one for construction. As 

described earlier in this preamble, in 

construction, OSHA has provided a 

table—labeled Table 1, Exposure 

Control Methods for Selected 

Construction Operations—that for 

special operations enables the employer 

to implement engineering controls, 

work practices, and respiratory 

protection without the need for 

exposure assessment. Table 1 in the 

proposed construction standard 

presents engineering and work practice 

controls and respiratory protection 

options for special operations. Where 

employees perform the special 

operations listed in the table and the 

employer has fully implemented the 

engineering controls, work practices, 

and respiratory protection specified in 

the table, the employer is not required 

to assess the exposure of employees 

performing such operations. 

As an alternative to the regulated area 

provision, OSHA is proposing that 

employers be permitted the option of 

establishing written access control plans 

that must contain provisions for a 

competent person; procedures for 

notifying employees of the presence of 

exposure to respirable crystalline silica 

and demarcating such areas from the 

rest of the workplace; in multi-employer 

workplaces, the methods for informing 

other employers of the presence and 

location of areas where silica exposures 

may exceed the PEL; provisions for 

limiting access to areas where silica 

exposures are likely; and procedures for 

providing respiratory protection to 

employees entering areas with 

controlled access. Further discussion on 

this alternative is found in the Summary 

and Explanation for paragraph (e) 

Regulated Areas and Access Control. 

OSHA believes that, although the 

estimated per-worker cost for written 

access control plans averages somewhat 

higher than the per-worker cost for 

regulated areas ($199.29 per worker for 

the control plans vs. $167.65 per worker 

for the regulated area), access control 

plans may be significantly less costly 

and more protective than regulated 

areas in certain work situations. 

Some SERs were already applying 

many of the protective controls and 

practices that would be required by the 

ancillary provisions of the standard. 

However, many SERs objected to the 

provisions regarding housekeeping, 

protective clothing, and hygiene 

facilities. For this proposed rule, OSHA 

removed the requirement for hygiene 

facilities, which has resulted in the 

elimination of compliance costs for 

change rooms, shower facilities, lunch 

rooms, and hygiene-specific 

housekeeping requirements. OSHA also 

restricted the provision for protective 

clothing (or, alternatively, any other 

means to remove excessive silica dust 

from work clothing) to situations where 

there is the potential for employees’ 

work clothing to become grossly 

contaminated with finely divided 

material containing crystalline silica. 

b. Regulatory Alternatives 

For the convenience of those persons 

interested only in OSHA’s regulatory 

flexibility analysis, this section repeats 

the discussion of the various regulatory 

alternatives to the proposed OSHA 

silica standard presented in the 

Introduction and in Section VIII.H of 

this preamble. 

Each regulatory alternative presented 

here is described and analyzed relative 

to the proposed rule. Where 

appropriate, the Agency notes whether 

the regulatory alternative, to be a 

legitimate candidate for OSHA 

consideration, requires evidence 

contrary to the Agency’s findings of 

significant risk and feasibility. To 

facilitate comment, the regulatory 

alternatives have been organized into 

four categories: (1) Alternative PELs to 

the proposed PEL of 50 mg/m3; (2) 

regulatory alternatives that affect 

proposed ancillary provisions; (3) a 

regulatory alternative that would modify 

the proposed methods of compliance; 

and (4) regulatory alternatives 

concerning when different provisions of 

the proposed rule would take effect. 

Alternative PELs 

OSHA is proposing a new PEL for 

respirable crystalline silica of 50 mg/m3

for all industry sectors covered by the 

rule. OSHA’s proposal is based on the 

requirements of the Occupational Safety 

and Health Act (OSH Act) and court 

interpretations of the Act. For health 

standards issued under section 6(b)(5) of 

the OSH Act, OSHA is required to 

promulgate a standard that reduces 

significant risk to the extent that it is 

technologically and economically 

feasible to do so. See Section II of this 

preamble, Pertinent Legal Authority, for 

a full discussion of OSHA legal 

requirements. 

OSHA has conducted an extensive 

review of the literature on adverse 

health effects associated with exposure 

to respirable crystalline silica. The 

Agency has also developed estimates of 

the risk of silica-related diseases 

assuming exposure over a working 

lifetime at the proposed PEL and action 

level, as well as at OSHA’s current 

PELs. These analyses are presented in a 

background document entitled 

‘‘Respirable Crystalline Silica—Health 

Effects Literature Review and 

Preliminary Quantitative Risk 

Assessment’’ and are summarized in 

this preamble in Section V, Health 

Effects Summary, and Section VI, 

Summary of OSHA’s Preliminary 

Quantitative Risk Assessment, 

respectively. The available evidence 

indicates that employees exposed to 

respirable crystalline silica well below 

the current PELs are at increased risk of 

lung cancer mortality and silicosis 

mortality and morbidity. Occupational 

exposures to respirable crystalline silica 

also may result in the development of 

kidney and autoimmune diseases and in 

death from other nonmalignant 

respiratory diseases. As discussed in 

Section VII, Significance of Risk, in this 

preamble, OSHA preliminarily finds 

that worker exposure to respirable 

crystalline silica constitutes a 

significant risk and that the proposed 

standard will substantially reduce this 

risk. 

Section 6(b) of the OSH Act (29 U.S.C. 

655(b)) requires OSHA to determine that 

its standards are technologically and 

economically feasible. OSHA’s 

examination of the technological and 

economic feasibility of the proposed 

rule is presented in the Preliminary 

Economic Analysis and Initial 

Regulatory Flexibility Analysis (PEA), 

and is summarized in this section 

(Section VIII) of this preamble. For 

general industry and maritime, OSHA 

has preliminarily concluded that the 

proposed PEL of 50 mg/m3 is 

technologically feasible for all affected 

industries. For construction, OSHA has 

preliminarily determined that the 

proposed PEL of 50 mg/m3 is feasible in 

10 out of 12 of the affected activities. 

Thus, OSHA preliminarily concludes 

that engineering and work practices will 

be sufficient to reduce and maintain 

silica exposures to the proposed PEL of 

50 mg/m3 or below in most operations 

most of the time in the affected 

industries. For those few operations 

within an industry or activity where the 

proposed PEL is not technologically 

feasible even when workers use 

recommended engineering and work 

practice controls, employers can 

supplement controls with respirators to 

achieve exposure levels at or below the 

proposed PEL. 

OSHA developed quantitative 

estimates of the compliance costs of the 

proposed rule for each of the affected 

industry sectors. The estimated 

compliance costs were compared with 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56423 

industry revenues and profits to provide 

a screening analysis of the economic 

feasibility of complying with the revised 

standard and an evaluation of the 

potential economic impacts. Industries 

with unusually high costs as a 

percentage of revenues or profits were 

further analyzed for possible economic 

feasibility issues. After performing these 

analyses, OSHA has preliminarily 

concluded that compliance with the 

requirements of the proposed rule 

would be economically feasible in every 

affected industry sector. 

OSHA has examined two regulatory 

alternatives (named Regulatory 

Alternatives #1 and #2) that would 

modify the PEL for the proposed rule. 

Under Regulatory Alternative #1, the 

proposed PEL would be changed from 

50 mg/m3 to 100 mg/m3 for all industry 

sectors covered by the rule, and the 

action level would be changed from 25 

mg/m3 to 50 mg/m3 (thereby keeping the 

action level at one-half of the PEL). 

Under Regulatory Alternative #2, the 

proposed PEL would be lowered from 

50 mg/m3 to 25 mg/m3 for all industry 

sectors covered by the rule, while the 

action level would remain at 25 mg/m3

(because of difficulties in accurately 

measuring exposure levels below 25 mg/ 

m3). 

Tables VIII–31A and VIII–31B 

present, for informational purposes, the 

estimated costs, benefits, and net 

benefits of the proposed rule under the 

proposed PEL of 50 mg/m3 and for the 

regulatory alternatives of a PEL of 100 

mg/m3 and a PEL of 25 mg/m3

(Regulatory Alternatives # 1 and #2), 

using alternative discount rates of 3 and 

7 percent. These two tables also present 

the incremental costs, the incremental 

benefits, and the incremental net 

benefits of going from a PEL of 100 mg/ 

m3 to the proposed PEL of 50 mg/m3 and 

then of going from the proposed PEL of 

50 mg/m3 to a PEL of 25 mg/m3. Table 

VIII–31A breaks out costs by provision 

and benefits by type of disease and by 

morbidity/mortality, while Table VIII– 

31B breaks out costs and benefits by 

major industry sector. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2


EP12SE13.018</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table VIII-31A: Annualized Costs, Benefits and Incremental Benefits of OSHA's Proposed Silica Standard of 50 J.lg/m3 and 100 J.lg/m3 Alternative 

Millions ($2009) 

Incremental Costs/Benefits 501!g/m3 Incremental Costs/Benef

Discount Rate 3% 

Annualized Costs 

Engineering Controls (includes Abrasive Blasting) $330 $344 $0 $0 $330 $344 $187 $197 Respirators $421 $422 $330 $331 $91 $91 $88 $88 Exposure Assessment $203 $203 $131 $129 $73 $74 $26 $26 Medical Surveillance $219 $227 $143 $148 $76 $79 $28 $29 

Training $49 $50 $0 $0 $49 $50 $0 $0 

Regulated Area or Access Control $85 $86 $66 $66 

Total Annualized Costs (point estimate) $1,308 $1,332 $670 $674 $637 $658 $339 $351 

Annual Benefits: Number of Cases Prevented Cases Cases Cases Cases 

Fatal Lung Cancers (midpoint estimate) 23'7 75 """""i62 79 Fatal Silicosis & other Non-Malignant 527 152 375 186 Respiratory Diseases Fatal Renal Disease 258 108 151 91 

Silica-Related Mortality 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,116 

Silicosis Morbidity 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $544 

Monetized Annual Benefits (midpoint estimate) $7,030 $4,684 $1,776 $1,188 $5,254 $3,495 $2,495 $1,659 

Net Benefits $5,722 $3,352 $1,105 $514 $4,617 $2,838 $2,157 $1,308 

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory Analysis 
As Tables VIII–31A and VIII–31B 

show, going from a PEL of 100 mg/m3 to 

a PEL of 50 mg/m3 would prevent, 

annually, an additional 357 silica- cases of silicosis. Based on its 

related fatalities and an additional 632 


EP12SE13.019</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Table VIII-31B: Annualized Costs, Benefits and Incremental Benefits of OSHA's Proposed Silica Standard of 50 I'g/m3 and 100 I'g/m3 Alternative, by Major 

Millions ($2009) 

251!g/m3 Incremental Costs/Benefits 50 I!g/m3 Incremental Costs/Be

Discount Rate 

Annualized Costs 

Construction $1,043 $1,062 $548 $551 $495 $511 $233 $24

General Industry/Maritime $264 $270 $122 $123 $143 $147 $106 $11

----

Total Annualized Costs $1,308 $1,332 $670 $674 $637 $658 $339 $35

Annual Benefits: Number of Cases 

Prevented Cases Cases Cases Cases 

Silica-Related Mortality 

Construction 802 $3,804 $2,504 235 $1,109 $746 567 $2,695 $1,758 242 $1,158 $760 

General Industry/Maritime 221 $1,007 $657 100 $434 $283 121 $573 $374 115 $545 $356 

Total 1,023 $4,811 $3,160 335 $1,543 $1,028 688 $3,268 $2,132 357 $1,704 $1,116 

Silicosis Morbidity 

Construction 1,157 $1,451 $996 77 $96 $66 1,080 $1,354 $930 161 $202 $139 

General Industry/Maritime 613 $768 $528 109 $136 $94 504 $632 $434 471 $590 $405 

Total 1,770 $2,219 $1,523 186 $233 $160 1,585 $1,986 $1,364 632 $792 $544 

Monetized Annual Benefits (midpoint 

estimate) 

Construction $5,255 $3,500 $1,205 $812 $4,049 $2,688 $1,360 $898 

Generallndustry/Maritime $1,775 $1.184 $570 $377 $1,205 $808 $1,135 $761 

Total $7,030 $4,684 $1,776 $1,188 $5,254 $3,495 $2,495 $1,659 

Net Benefits 

Construction $4,211 $2,437 $657 $261 $3,555 $2,177 $1,127 $658 

General Industry/Maritime $1,511 $914 $448 $254 $1,062 $661 $1,029 $651 

Total $5,722 $3,352 $1,105 $514 $4,617 $2,838 $2,157 $1,308 

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory Analysis 
56426 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

preliminary findings that the proposed 

PEL of 50 mg/m3 significantly reduces 

worker risk from silica exposure (as 

demonstrated by the number of silicarelated fatalities and silicosis cases 

avoided) and is both technologically 

and economically feasible, OSHA 

cannot propose a PEL of 100 mg/m3

(Regulatory Alternative #1) without 

violating its statutory obligations under 

the OSH Act. However, the Agency will 

consider evidence that challenges its 

preliminary findings. 

As previously noted, Tables VIII–31A 

and VIII–31B also show the costs and 

benefits of a PEL of 25 mg/m3

(Regulatory Alternative #2), as well as 

the incremental costs and benefits of 

going from the proposed PEL of 50 mg/ 

m3 to a PEL of 25 mg/m3. Because OSHA 

determined that a PEL of 25 mg/m3

would not be feasible (that is, 

engineering and work practices would 

not be sufficient to reduce and maintain 

silica exposures to a PEL of 25 mg/m3 or 

below in most operations most of the 

time in the affected industries), the 

Agency did not attempt to identify 

engineering controls or their costs for 

affected industries to meet this PEL. 

Instead, for purposes of estimating the 

costs of going from a PEL of 50 mg/m3

to a PEL of 25 mg/m3, OSHA assumed 

that all workers exposed between 50 mg/ 

m3 and 25 mg/m3 would have to wear 

respirators to achieve compliance with 

the 25 mg/m3 PEL. OSHA then estimated 

the associated additional costs for 

respirators, exposure assessments, 

medical surveillance, and regulated 

areas (the latter three for ancillary 

requirements specified in the proposed 

rule). 

As shown in Tables VIII–31A and 

VIII–31B, going from a PEL of 50 mg/m3

to a PEL of 25 mg/m3 would prevent, 

annually, an additional 335 silicarelated fatalities and an additional 186 

cases of silicosis. These estimates 

support OSHA’s preliminarily finding 

that there is significant risk remaining at 

the proposed PEL of 50 mg/m3. However, 

the Agency has preliminarily 

determined that a PEL of 25 mg/m3

(Regulatory Alternative #2) is not 

technologically feasible, and for that 

reason, cannot propose it without 

violating its statutory obligations under 

the OSH Act. 

Regulatory Alternatives That Affect 

Ancillary Provisions 

The proposed rule contains several 

ancillary provisions (provisions other 

the PEL), including requirements for 

exposure assessment, medical 

surveillance, silica training, and 

regulated areas or access control. As 

shown in Table VIII–31A, these 

ancillary provisions represent 

approximately $223 million (or about 34 

percent) of the total annualized costs of 

the rule of $658 million (using a 7 

percent discount rate). The two most 

expensive of the ancillary provisions are 

the requirements for medical 

surveillance, with annualized costs of 

$79 million, and the requirements for 

exposure monitoring, with annualized 

costs of $74 million. 

As proposed, the requirements for 

exposure assessment are triggered by the 

action level. As described in the 

preamble, OSHA has defined the action 

level for the proposed standard as an 

airborne concentration of respirable 

crystalline silica of 25 mg/m3 calculated 

as an eight-hour time-weighted average. 

In this proposal, as in other standards, 

the action level has been set at one-half 

of the PEL. 

Because of the variable nature of 

employee exposures to airborne 

concentrations of respirable crystalline 

silica, maintaining exposures below the 

action level provides reasonable 

assurance that employees will not be 

exposed to respirable crystalline silica 

at levels above the PEL on days when 

no exposure measurements are made. 

Even when all measurements on a given 

day may fall below the PEL (but are 

above the action level), there is some 

chance that on another day, when 

exposures are not measured, the 

employee’s actual exposure may exceed 

the PEL. When exposure measurements 

are above the action level, the employer 

cannot be reasonably confident that 

employees have not been exposed to 

respirable crystalline silica 

concentrations in excess of the PEL 

during at least some part of the work 

week. Therefore, requiring periodic 

exposure measurements when the 

action level is exceeded provides the 

employer with a reasonable degree of 

confidence in the results of the exposure 

monitoring. 

The action level is also intended to 

encourage employers to lower exposure 

levels in order to avoid the costs 

associated with the exposure assessment 

provisions. Some employers would be 

able to reduce exposures below the 

action level in all work areas, and other 

employers in some work areas. As 

exposures are lowered, the risk of 

adverse health effects among workers 

decreases. 

OSHA’s preliminary risk assessment 

indicates that significant risk remains at 

the proposed PEL of 50 mg/m3. Where 

there is continuing significant risk, the 

decision in the Asbestos case (Bldg. and 

Constr.Trades Dep’t, AFL–CIO v. Brock, 

838 F.2d 1258, 1274 (D.C. Cir. 1988)) 

indicated that OSHA should use its 

legal authority to impose additional 

requirements on employers to further 

reduce risk when those requirements 

will result in a greater than de minimis 

incremental benefit to workers’ health. 

OSHA’s preliminary conclusion is that 

the requirements triggered by the action 

level will result in a very real and 

necessary, but non-quantifiable, further 

reduction in risk beyond that provided 

by the PEL alone. OSHA’s choice of 

proposing an action level for exposure 

monitoring of one-half of the PEL is 

based on the Agency’s successful 

experience with other standards, 

including those for inorganic arsenic (29 

CFR 1910.1018), ethylene oxide (29 CFR 

1910.1047), benzene (29 CFR 

1910.1028), and methylene chloride (29 

CFR 1910.1052). 

As specified in the proposed rule, all 

workers exposed to respirable 

crystalline silica above the PEL of 50 mg/ 

m3 are subject to the medical 

surveillance requirements. This means 

that the medical surveillance 

requirements would apply to 15,172 

workers in general industry and 336,244 

workers in construction. OSHA 

estimates that 457 possible silicosis 

cases will be referred to pulmonary 

specialists annually as a result of this 

medical surveillance. 

OSHA has preliminarily determined 

that these ancillary provisions will: (1) 

Help to ensure the PEL is not exceeded, 

and (2) minimize risk to workers given 

the very high level of risk remaining at 

the PEL. OSHA did not estimate, and 

the benefits analysis does not include, 

monetary benefits resulting from early 

discovery of illness. 

Because medical surveillance and 

exposure assessment are the two most 

costly ancillary provisions in the 

proposed rule, the Agency has 

examined four regulatory alternatives 

(named Regulatory Alternatives #3, #4, 

#5, and #6) involving changes to one or 

the other of these ancillary provisions. 

These four regulatory alternatives are 

defined below and the incremental cost 

impact of each is summarized in Table 

VIII–32. In addition, OSHA is including 

a regulatory alternative (named 

Regulatory Alternative #7) that would 

remove all ancillary provisions. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Under Regulatory Alternative #3, the 

action level would be raised from 25 mg/ 

m3 to 50 mg/m3 while keeping the PEL 

at 50 mg/m3. As a result, exposure triggered only if workers were exposed 

monitoring requirements would be 


EP12SE13.020</GPH>mstockstill on DSK4VPTVN1PROD with PROPOSALS2

13% Discount Rate I 

Proposed Rule 

Option 3: PEL=50; AL=50 

Option 4: PEL=50; AL =25, with 

medical surveillance triggered by AL 

Option 5: PEL=50; AL=25, with 

medical exams annually 

Option 6: PEL=50; AL=25, with 

surveillance triggered by AL and 

medical exams annually 

(7%·biscountRatel 

Proposed Rule 

Option 3: PEL=50; AL=50 

Option 4: PEL=50; AL =25, with 

medical surveillance triggered by AL 

Option 5: PEL=50; AL=25, with 

medical exams annually 

Option 6: PEL=50; AL=25, with 

surveillance triggered by AL and 

medical exams annually 

Table VIII-32: Cost of Regulatory Alternatives Affecting Ancillary Provisions 

Cost Incremental Co

Construction GIIM Total Construction 

$494,826,699 $142,502,681 $637,329,380 

$457,686,162 $117,680,601 $575,366,763 -$37,140,537 -$

$606,697,624 $173,701,827 $780,399,451 $111,870,925 $

$561,613,766 $145,088,559 $706,702,325 $66,787,067 

$775,334,483 $203,665,685 $979,000,168 $280,507,784 $

Cost Incremental Co

Construction GIIM Total Construction 

$511,165,616 $146,726,595 $657,892,211 

$473,638,698 $121,817,396 $595,456,093 -$37,526,918 -$

$627,197,794 $179,066,993 $806,264,787 $132,371,095 $

$575,224,843 $149,204,718 $724,429,561 $64,059,227 $791,806,358 $208,339,741 $1,000,146,099 $280,640,742 $

Source: U.S. Department of Labor, Occupational Safety and Health Administration, Directorate of Evaluation and Analysis, Office of Regulatory A
56428 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

above the proposed PEL of 50 mg/m3. As 

shown in Table VIII–32, Regulatory 

Option #3 would reduce the annualized 

cost of the proposed rule by about $62 

million, using a discount rate of either 

3 percent or 7 percent. 

Under Regulatory Alternative #4, the 

action level would remain at 25 mg/m3

but medical surveillance would now be 

triggered by the action level, not the 

PEL. As a result, medical surveillance 

requirements would be triggered only if 

workers were exposed at or above the 

proposed action level of 25 mg/m3. As 

shown in Table VIII–32, Regulatory 

Option #4 would increase the 

annualized cost of the proposed rule by 

about $143 million, using a discount 

rate of 3 percent (and by about $169 

million, using a discount rate of 7 

percent). 

Under Regulatory Alternative #5, the 

only change to the proposed rule would 

be to the medical surveillance 

requirements. Instead of requiring 

workers exposed above the PEL to have 

a medical check-up every three years, 

those workers would be required to 

have a medical check-up annually. As 

shown in Table VIII–32, Regulatory 

Option #5 would increase the 

annualized cost of the proposed rule by 

about $69 million, using a discount rate 

of 3 percent (and by about $66 million, 

using a discount rate of 7 percent). 

Regulatory Alternative #6 would 

essentially combine the modified 

requirements in Regulatory Alternatives 

#4 and #5. Under Regulatory Alternative 

#6, medical surveillance would be 

triggered by the action level, not the 

PEL, and workers exposed at or above 

the action level would be required to 

have a medical check-up annually 

rather than triennially. The exposure 

monitoring requirements in the 

proposed rule would not be affected. As 

shown in Table VIII–32, Regulatory 

Option #6 would increase the 

annualized cost of the proposed rule by 

about $342 million, using a discount 

rate of either 3 percent or 7 percent. 

OSHA is not able to quantify the 

effects of these preceding four 

regulatory alternatives on protecting 

workers exposed to respirable 

crystalline silica at levels at or below 

the proposed PEL of 50 mg/m3—where 

significant risk remains. The Agency 

solicits comment on the extent to which 

these regulatory options may improve or 

reduce the effectiveness of the proposed 

rule. 

The final regulatory alternative 

affecting ancillary provisions, 

Regulatory Alternative #7, would 

eliminate all of the ancillary provisions 

of the proposed rule, including 

exposure assessment, medical 

surveillance, training, and regulated 

areas or access control. However, it 

should be carefully noted that 

elimination of the ancillary provisions 

does not mean that all costs for ancillary 

provisions would disappear. In order to 

meet the PEL, employers would still 

commonly need to do monitoring, train 

workers on the use of controls, and set 

up some kind of regulated areas to 

indicate where respirator use would be 

required. It is also likely that employers 

would increasingly follow the many 

recommendations to provide medical 

surveillance for employees. OSHA has 

not attempted to estimate the extent to 

which the costs of these activities would 

be reduced if they were not formally 

required, but OSHA welcomes comment 

on the issue. 

As indicated previously, OSHA 

preliminarily finds that there is 

significant risk remaining at the 

proposed PEL of 50 mg/m3. However, the 

Agency has also preliminarily 

determined that 50 mg/m3 is the lowest 

feasible PEL. Therefore, the Agency 

believes that it is necessary to include 

ancillary provisions in the proposed 

rule to further reduce the remaining 

risk. OSHA anticipates that these 

ancillary provisions will reduce the risk 

beyond the reduction that will be 

achieved by a new PEL alone. 

OSHA’s reasons for including each of 

the proposed ancillary provisions are 

detailed in Section XVI of this 

preamble, Summary and Explanation of 

the Standards. In particular, OSHA 

believes that requirements for exposure 

assessment (or alternately, using 

specified exposure control methods for 

selected construction operations) would 

provide a basis for ensuring that 

appropriate measures are in place to 

limit worker exposures. Medical 

surveillance is particularly important 

because individuals exposed above the 

PEL (which triggers medical 

surveillance in the proposed rule) are at 

significant risk of death and illness. 

Medical surveillance would allow for 

identification of respirable crystalline 

silica-related adverse health effects at an 

early stage so that appropriate 

intervention measures can be taken. 

OSHA believes that regulated areas and 

access control are important because 

they serve to limit exposure to 

respirable crystalline silica to as few 

employees as possible. Finally, OSHA 

believes that worker training is 

necessary to inform employees of the 

hazards to which they are exposed, 

along with associated protective 

measures, so that employees understand 

how they can minimize potential health 

hazards. Worker training on silicarelated work practices is particularly 

important in controlling silica 

exposures because engineering controls 

frequently require action on the part of 

workers to function effectively. 

OSHA expects that the benefits 

estimated under the proposed rule will 

not be fully achieved if employers do 

not implement the ancillary provisions 

of the proposed rule. For example, 

OSHA believes that the effectiveness of 

the proposed rule depends on regulated 

areas or access control to further limit 

exposures and on medical surveillance 

to identify disease cases when they do 

occur. 

Both industry and worker groups have 

recognized that a comprehensive 

standard is needed to protect workers 

exposed to respirable crystalline silica. 

For example, the industry consensus 

standards for crystalline silica, ASTM E 

1132–06, Standard Practice for Health 

Requirements Relating to Occupational 

Exposure to Respirable Crystalline 

Silica, and ASTM E 2626–09, Standard 

Practice for Controlling Occupational 

Exposure to Respirable Crystalline 

Silica for Construction and Demolition 

Activities, as well as the draft proposed 

silica standard for construction 

developed by the Building and 

Construction Trades Department, AFL– 

CIO, have each included comprehensive 

programs. These recommended 

standards include provisions for 

methods of compliance, exposure 

monitoring, training, and medical 

surveillance (ASTM, 2006; 2009; BCTD 

2001). Moreover, as mentioned 

previously, where there is continuing 

significant risk, the decision in the 

Asbestos case (Bldg. and Constr. Trades 

Dep’t, AFL–CIO v. Brock, 838 F.2d 1258, 

1274 (DC Cir. 1988)) indicated that 

OSHA should use its legal authority to 

impose additional requirements on 

employers to further reduce risk when 

those requirements will result in a 

greater than de minimis incremental 

benefit to workers’ health. OSHA 

preliminarily concludes that the 

additional requirements in the ancillary 

provisions of the proposed standard 

clearly exceed this threshold. 

A Regulatory Alternative That Modifies 

the Methods of Compliance 

The proposed standard in general 

industry and maritime would require 

employers to implement engineering 

and work practice controls to reduce 

employees’ exposures to or below the 

PEL. Where engineering and/or work 

practice controls are insufficient, 

employers would still be required to 

implement them to reduce exposure as 

much as possible, and to supplement 

them with a respiratory protection 

program. Under the proposed 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56429 

construction standard, employers would 

be given two options for compliance. 

The first option largely follows 

requirements for the general industry 

and maritime proposed standard, while 

the second option outlines, in Table 1 

(Exposure Control Methods for Selected 

Construction Operations) of the 

proposed rule, specific construction 

exposure control methods. Employers 

choosing to follow OSHA’s proposed 

control methods would be considered to 

be in compliance with the engineering 

and work practice control requirements 

of the proposed standard, and would 

not be required to conduct certain 

exposure monitoring activities. 

One regulatory alternative (Regulatory 

Alternative #8) involving methods of 

compliance would be to eliminate Table 

1 as a compliance option in the 

construction sector. Under this 

regulatory alternative, OSHA estimates 

that there would be no effect on 

estimated benefits but that the 

annualized costs of complying with the 

proposed rule (without the benefit of the 

Table 1 option in construction) would 

increase by $175 million, totally in 

exposure monitoring costs, using a 3 

percent discount rate (and by $178 

million using a 7 percent discount rate), 

so that the total annualized compliance 

costs for all affected establishments in 

construction would increase from $495 

to $670 million using a 3 percent 

discount rate (and from $511 to $689 

million using a 7 percent discount rate). 

Regulatory Alternatives That Affect the 

Timing of the Standard 

The proposed rule would become 

effective 60 days following publication 

of the final rule in the Federal Register. 

Provisions outlined in the proposed 

standard would become enforceable 180 

days following the effective date, with 

the exceptions of engineering controls 

and laboratory requirements. The 

proposed rule would require 

engineering controls to be implemented 

no later than one year after the effective 

date, and laboratory requirements 

would be required to begin two years 

after the effective date. 

One regulatory alternative (Regulatory 

Alternative #9) involving the timing of 

the standard would arise if, contrary to 

OSHA’s preliminary findings, a PEL of 

50 mg/m3 with an action level of 25 mg/ 

m3 were found to be technologically and 

economically feasible some time in the 

future (say, in five years), but not 

feasible immediately. In that case, 

OSHA might issue a final rule with a 

PEL of 50 mg/m3 and an action level of 

25 mg/m3 to take effect in five years, but 

at the same time issue an interim PEL 

of 100 mg/m3 and an action level of 50 

mg/m3 to be in effect until the final rule 

becomes feasible. Under this regulatory 

alternative, and consistent with the 

public participation and ‘‘look back’’ 

provisions of Executive Order 13563, 

the Agency could monitor compliance 

with the interim standard, review 

progress toward meeting the feasibility 

requirements of the final rule, and 

evaluate whether any adjustments to the 

timing of the final rule would be 

needed. Under Regulatory Alternative 

#9, the estimated costs and benefits 

would be somewhere between those 

estimated for a PEL of 100 mg/m3 with 

an action level of 50 mg/m3 and those 

estimated for a PEL of 50 mg/m3 with an 

action level of 25 mg/m3, the exact 

estimates depending on the length of 

time until the final rule is phased in. 

OSHA emphasizes that this regulatory 

alternative is contrary to the Agency’s 

preliminary findings of economic 

feasibility and, for the Agency to 

consider it, would require specific 

evidence introduced on the record to 

show that the proposed rule is not now 

feasible but would be feasible in the 

future. 

Although OSHA did not explicitly 

develop or quantitatively analyze any 

other regulatory alternatives involving 

longer-term or more complex phase-ins 

of the standard (possibly involving more 

delayed implementation dates for small 

businesses), OSHA is soliciting 

comments on this issue. Such a 

particularized, multi-year phase-in 

would have several advantages, 

especially from the viewpoint of 

impacts on small businesses. First, it 

would reduce the one-time initial costs 

of the standard by spreading them out 

over time, a particularly useful 

mechanism for small businesses that 

have trouble borrowing large amounts of 

capital in a single year. A differential 

phase-in for smaller firms would also 

aid very small firms by allowing them 

to gain from the control experience of 

larger firms. A phase-in would also be 

useful in certain industries—such as 

foundries, for example—by allowing 

employers to coordinate their 

environmental and occupational safety 

and health control strategies to 

minimize potential costs. However a 

phase-in would also postpone the 

benefits of the standard. 

As previous discussed in the 

Introduction and in Section VIII.H of 

this preamble, OSHA requests 

comments on these regulatory 

alternatives, including the Agency’s 

choice of regulatory alternatives (and 

whether there are other regulatory 

alternatives the Agency should 

consider) and the Agency’s analysis of 

them. 

SBREFA Panel 

Table VIII–33 lists all of the SBREFA 

Panel recommendations and OSHA’s 

responses to these recommendations. 

TABLE VIII–33—SBREFA PANEL RECOMMENDATIONS AND OSHA RESPONSES

SBREFA Panel recommendation OSHA response 

The Panel recommended that OSHA give consideration to the alternative of improved enforcement of and expanded outreach for the 

existing rule rather than a new rule. In addition, the Panel recommended that OSHA carefully study the effects of existing compliance and outreach efforts, such as the Special Emphasis Program 

on silica, with a view to better delineating the effects of such efforts. 

This examination should include (1) a year-by-year analysis of the 

extent of noncompliance discovered in OSHA compliance inspections, and (2) the kinds of efforts OSHA made to improve enforcement and outreach.

As discussed in Chapter II of the PEA, Need for Regulation (and summarized in Section VIII.B of this Preamble), OSHA has reviewed existing enforcement and outreach programs, as well as other legal 

and administrative remedies, and believes that a standard would be 

the most effective means to protect workers from exposure to silica. 

A review of OSHA’s compliance assistance efforts and an analysis of 

compliance with the current PELs for respirable crystalline silica are 

discussed in Section III of the preamble, Events Leading to the Proposed Standard. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56430 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–33—SBREFA PANEL RECOMMENDATIONS AND OSHA RESPONSES—Continued 

SBREFA Panel recommendation OSHA response 

(General Industry) The Panel recommended that OSHA revise its economic and regulatory flexibility analyses as appropriate to reflect the 

SERs’ comments on underestimation of costs, and that the Agency 

compare OSHA’s revised estimates to alternative estimates provided 

and methodologies suggested by the SERs. For those SER estimates and methodological suggestions that OSHA does not adopt, 

the Panel recommends that OSHA explain its reasons for preferring 

an alternative estimate and solicit comment on the issue.

OSHA has reviewed its cost estimates in response to the comments 

received from the SERs and evaluated the alternative estimates and 

methodologies suggested by the SERs. In some cases (such as for 

exposure monitoring and training) OSHA has revised its cost estimates in response to SER comments. However, OSHA has not 

made all cost changes suggested by the SERs, but has retained (or 

simply updated) those cost estimates that OSHA determined reflect 

sound methodology and reliable data. OSHA requests comments on 

the Agency’s estimated costs and on the assumptions applied in the 

cost analysis, and has included this topic in Section I. Issues (See 

Compliance Costs) and in Chapter V of the PEA. 

The Panel recommended that, as time permits, OSHA revise its economic and regulatory flexibility analyses as appropriate to reflect the 

SERs’ comments on underestimation of costs and that the Agency 

compare the OSHA revised estimates to alternative estimates provided and methodologies suggested by the SERs. For those SER 

estimates and methodological suggestions that OSHA does not 

adopt, the Panel recommends that OSHA explain its reasons for preferring an alternative estimate and solicit comment on the issue.

OSHA has extensively reviewed its costs estimates, changed many of 

them in response to SER comments, and solicits comments on these 

revised cost estimates. A few examples of OSHA’s cost changes are 

given in the responses to specific issues below (e.g., exposure monitoring, medical exams, training and familiarization). OSHA requests 

comments on the Agency’s estimated costs and on the assumptions 

applied in the cost analysis, and has included this topic in Section I. 

Issues (See Compliance Costs) and in Chapter V of the PEA. 

The Panel recommended that prior to publishing a proposed standard, 

OSHA should carefully consider the ability of each potentially affected industry to meet any proposed PEL for silica, and that OSHA 

should recognize, and incorporate in its cost estimates, specific 

issues or hindrances that different industries may have in implementing effective controls.

The PEA reflects OSHA’s judgment on technological feasibility and includes responses to specific issues raised by the Panel and SERs. 

OSHA solicits comment on the accuracy and reasonableness of 

these judgments and has included this topic in Section I. Issues (See 

Technological and Economic Feasibility of the Proposed PEL and 

Compliance Costs). 

The Panel recommended that OSHA carefully review the basis for its 

estimated exposure monitoring costs, consider the concerns raised 

by the SERs, and ensure that its estimates are revised, as appropriate, to fully reflect the costs likely to be incurred by potentially affected establishments.

Table 1 in the proposed standard is designed to relieve establishments 

in construction from requirements for exposure assessment when 

certain controls are established. OSHA developed cost estimates in 

the PEA for exposure monitoring as a function of the size of the establishment. OSHA’s cost estimates now reflect the fact that smaller 

entities will tend to experience larger unit costs. OSHA estimated 

higher exposure monitoring costs for small entities because an industrial hygienist could not take as many samples a day in a small 

establishment as in a large one. OSHA believes that its unit cost estimates for exposure monitoring are realistic but will raise that as an 

issue. See Chapter V of the PEA for details of OSHA’s unit costs for 

exposure monitoring in general industry and maritime. 

The Panel recommended that OSHA carefully review the basis for its 

estimated health screening compliance costs, consider the concerns 

raised by the SERs, and ensure that its estimates are revised, as appropriate, to fully reflect the costs likely to be incurred by potentially 

affected establishments.

OSHA’s cost estimates for health screening are a function of the size 

of the establishment. OSHA’s cost estimates now reflect the fact that 

smaller entities will tend to experience larger unit costs. OSHA estimated higher medical surveillance costs (than was estimated in the 

Preliminary Initial Regulatory Flexibility Analysis (PIRFA)) for small 

entities because smaller establishments would be more likely to send 

the workers off-site for medical testing. In addition, OSHA significantly increased the total costs of exposure sampling and x-rays in 

medical surveillance by assuming no existing compliance with the 

those provisions in the proposed rule (as compared to an average of 

32.6 percent and 34.8 percent existing compliance, respectively, in 

the PIRFA). 

(Construction) The Panel recommended that OSHA carefully review the 

basis for its estimated hygiene compliance costs, consider the concerns raised by the SERs, and ensure that its estimates are revised, 

as appropriate, to fully reflect the costs likely to be incurred by potentially affected establishments.

OSHA removed the specific hygiene provisions in the proposed rule, 

which has resulted in the elimination of compliance costs for changing rooms, shower facilities, lunch rooms, and hygiene-specific 

housekeeping requirements. However, OSHA has retained requirements and cost estimates for disposable clothing (in regulated areas) 

where there is the potential for employees’ work clothing to become 

grossly contaminated with finely divided material containing crystalline silica. 

The Panel recommended that OSHA carefully review the issue of dry 

sweeping in the analysis, consider the concerns raised by the SERs, 

and ensure that its estimates are revised, as appropriate, to fully reflect the costs likely to be incurred by potentially affected establishments.

Dry sweeping remains a prohibited activity in the proposed standard 

and OSHA has estimated the costs for the use of wet methods to 

control dust (see Table VIII–30, above). OSHA requests comment on 

the use of wet methods as a substitute for dry sweeping and has included this topic in Section I. Issues (See Compliance Costs and 

Provisions of the Standards—Methods of compliance). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56431 

TABLE VIII–33—SBREFA PANEL RECOMMENDATIONS AND OSHA RESPONSES—Continued 

SBREFA Panel recommendation OSHA response 

The Panel recommended that OSHA carefully review the basis for its 

training costs, consider the concerns raised by the SERs, and ensure that its estimates are revised, as appropriate, to fully reflect the 

costs likely to be incurred by potentially affected establishments.

One participant in the silica SBREFA process objected to ERG’s analytical assumption (used in OSHA’s Preliminary Initial Regulatory 

Flexibility Analysis) that training is needed only for those workers exposed above the action level and suggested that training might be 

necessary for all at-risk workers. For the proposed rule, the scope of 

this requirement was revised so that the provision now would apply 

to workers with any potential occupational exposure to respirable 

crystalline silica; OSHA has estimated training costs in the PEA accordingly. 

OSHA estimated higher training costs for small entities because of 

smaller-sized training classes and significantly increased training 

costs by assuming only half compliance for half of the affected establishments (compared to an average of 56 percent existing compliance for all establishments in the PIRFA). 

(Construction) SERs raised cost issues similar to those in general industry, but were particularly concerned about the impact in construction, given the high turnover rates in the industry.

The Panel recommended that OSHA carefully review the basis for its 

estimated compliance costs, consider the concerns raised by the 

SERs, and ensure that its estimates are revised, as appropriate, to 

fully reflect the costs likely to be incurred by potentially affected establishments.

The cost estimates in the PEA reflect OSHA’s best judgment and take 

the much higher labor turnover rates in construction into account 

when calculating costs. For the proposed rule, OSHA used the most 

recent BLS turnover rate of 64 percent for construction (versus a 

turnover rate of 27.2 percent for general industry). OSHA believes 

that the estimates in the PEA capture the effect of high turnover 

rates in construction and solicits comments on this issue in Section I. 

Issues (See Compliance Costs). 

(Construction) The Panel recommended that OSHA (1) carefully review 

the basis for its estimated labor costs, and issues related to the use 

of FTEs in the analysis, (2) consider the concerns raised by the 

SERs, and (3) ensure that its estimates are revised, as appropriate, 

to fully reflect the costs likely to be incurred by potentially affected 

establishments.

OSHA used the exposure profiles to estimate the number of full-timeequivalent (FTE) workers in construction who are exposed above the 

PEL. This would be the exposure profile if all exposed workers 

worked full-time only at the specified silica-generating tasks. In 

OSHA’s analysis, the actual number of workers exposed above the 

PEL is represented by two to five times the number of FTE workers, 

depending on the activity. The estimate of the total number of at-risk 

workers takes into account the fact that most workers, regardless of 

construction occupation, spend some time working on jobs where no 

silica contamination is present. For the control cost analysis, however, it matters only how many worker-days there are in which exposures are above the PEL. These are the worker-days in which controls are required. The control costs (as opposed to the program 

costs) are independent of the number of at-risk workers associated 

with these worker-days. OSHA emphasizes that the use of FTEs 

does not ‘‘discount’’ its estimates of aggregate control costs. 

(Construction) Some SERs requested that OSHA apply a 30-day exclusion for implementing engineering and work practice controls, as was 

reflected in the draft standard for general industry and maritime.

The Panel recommended that OSHA consider this change and request 

comment on the appropriateness of exempting operations that are 

conducted fewer than 30 days per year from the hierarchy requirement.

A 30-day exemption from the requirement to implement engineering 

and work practice controls was not included in the proposed standard for construction, and has been removed from the proposed 

standard for general industry. OSHA requests comment on a 30-day 

exemption, and has included this topic in Section I. Issues (See Provisions of the Standards—Methods of compliance). 

(Construction) The Panel recommended that OSHA consider and seek 

comment on the need to prohibit employee rotation as a means of 

complying with the PEL and the likelihood that employees would be 

exposed to other serious hazards if the Agency were to retain this 

provision.

The proposed prohibition on rotation is explained in the Summary and 

Explanation for paragraph (f) Methods of Compliance. OSHA solicits 

comment on the prohibition of employee rotation to achieve compliance when exposure levels exceed the PEL, and has included this 

topic in Section I. Issues (See Provisions of the Standards—Methods 

of compliance). 

(Construction) Some SERs questioned the scientific and legal basis for 

the draft prohibitions on the use of compressed air, brushing, and dry 

sweeping of silica-containing debris. Others raised feasibility concerns such as in instances where water or electric power was unavailable or where use of wet methods could damage construction 

materials.

The Panel recommended that OSHA carefully consider the need for 

and feasibility of these prohibitions given these concerns, and that 

OSHA seek comment on the appropriateness of such prohibitions.

As discussed in the Summary and Explanation of paragraph (f) Methods of Compliance, the prohibition against the use of compressed 

air, brushing, and dry sweeping applies to situations where such activities could contribute to employee exposure that exceeds the PEL. 

OSHA solicits comment on this issue, and has included this topic in 

Section I. Issues (See Provisions of the Standards—Methods of 

compliance). 

(Construction) The Panel recommended that OSHA carefully consider 

whether regulated area provisions should be included in the draft 

proposed standard, and, if so, where and how regulated areas are to 

be established. OSHA should also clarify in the preamble and in its 

compliance assistance materials how compliance is expected to be 

achieved in the various circumstances raised by the SERs.

As described in the Summary and Explanation for paragraph (e) Regulated Areas and Access Control, the proposed standard includes a 

provision for implementation of ‘‘access control plans’’ in lieu of establishing regulated areas. Clarification for establishing either a regulated area or an access control plan is provided in the Summary and 

Explanation. 

(Construction) The Panel recommended that OSHA clarify how the regulated area requirements would apply to multi-employer worksites in 

the draft standard or preamble, and solicit comments on site control 

issues.

The Summary and Explanation for paragraph (e) Regulated Areas and 

Access Control clarifies this requirement. OSHA requests comment 

on this topic, and has included this topic in Section I. Issues (See 

Compliance Costs and Provisions of the Standards—Methods of 

compliance). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56432 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–33—SBREFA PANEL RECOMMENDATIONS AND OSHA RESPONSES—Continued 

SBREFA Panel recommendation OSHA response 

(Construction) Many SERs were concerned with the extent to which 

they felt the draft proposed standard would require the use of respirators in construction activities.

The Panel recommended that OSHA carefully consider its respiratory 

protection requirements, the respiratory protection requirements in 

Table 1, and the PEL in light of this concern.

OSHA has made a preliminary determination that compliance with the 

proposed PEL can be achieved in most operations most of the time 

through the use of engineering and work practice controls. However, 

as described in the Summary and Explanation of paragraphs (f) 

Methods of Compliance and (g) Respiratory Protection and in the 

Technological Feasibility chapter of the PEA, use of respiratory protection will be required for some operations. OSHA solicits comment 

on this issue in Section I. Issues (See Technological and Economic 

Feasibility of the Proposed PEL). 

(Construction) The Panel recommended that OSHA carefully address 

the issues of reliability of exposure measurement for silica and laboratory requirements. The Panel also recommended that OSHA seek 

approaches to a construction standard that can mitigate the need for 

extensive exposure monitoring to the extent possible.

OSHA discusses the reliability of measuring respirable crystalline silica 

in the Technological Feasibility chapter of the PEA. An exemption for 

monitoring is also provided where the employer uses Table 1. As 

discussed in the Summary and Explanation for paragraph (d) Exposure Assessment, the proposed standard also allows a performance 

option for exposure assessment that is expected to reduce the 

amount of monitoring needed. OSHA solicits comment on this topic 

in Section I. Issues (See Provisions of the Standards—Exposure Assessment). 

(Construction) As in general industry, many SERs were concerned 

about all of these provisions because, they contended, silica is not 

recognized as either a take-home or dermal hazard. Further, many 

said that these provisions would be unusually expensive in the context of construction work. Other SERs pointed out that protective 

clothing could lead to heat stress problems in some circumstances.

The Panel recommended that OSHA carefully re-examine the need for 

these provisions in the construction industry and solicit comment on 

this issue.

As described in the Summary and Explanation for paragraph (e) Regulated Areas and Access Control, OSHA has proposed a limited requirement for use of protective clothing or other means to remove 

silica dust from contaminated clothing. This requirement would apply 

only in regulated areas where there is the potential for work clothing 

to become grossly contaminated with silica dust. No requirement for 

hygiene facilities is included in the proposed standard. OSHA solicits 

comment regarding appropriate requirements for use of protective 

clothing and hygiene facilities in Section I. Issues (See Provisions of 

the Standards—Regulated areas and access control). 

(Construction) The Panel recommended that OSHA explicitly examine 

the issue of availability of specialists called for by these provisions, 

and re-examine the costs and feasibility of such requirements based 

on their findings with respect to availability, as needed.

The provisions requiring B-readers and pulmonary specialists are discussed in the Summary and Explanation of paragraph (n) Medical 

Surveillance, and the numbers of available specialists are reported. 

OSHA solicits comment on this issue in Section I. Issues (See Provisions of the Standards—Medical surveillance). 

(Construction) The Panel recommended that OSHA carefully consider 

the need for pre-placement physicals in construction, the possibility 

of delayed initial screening (so only employees who had been on the 

job a certain number of days would be required to have initial 

screening), and solicit comment on this issue.

As described in the Summary and Explanation for paragraph (n) Medical Surveillance, an initial examination is required within 30 days 

after initial assignment to a job with exposure above the action level 

for more than 30 days per year. OSHA solicits comment on this proposed requirement in Section I. Issues (See Provisions of the Standards—Medical surveillance). 

(Construction) Like the general industry SERs, construction SERs 

raised the issue that they would prefer a warning label with wording 

similar to that used in asbestos and lead.

The Panel recommended that OSHA consider this suggestion and solicit comment on it.

The proposed standard does not specify wording for labels. OSHA solicits comment on this issue in Section I. Issues (See Provisions of 

the Standards—Hazard communication). 

(Construction) Some SERs questioned whether hazard communication 

requirements made sense on a construction site where there are 

tons of silica-containing dirt, bricks, and concrete.

The Panel recommended OSHA consider how to address this issue in 

the context of hazard communication.

The proposed standard requires hazard communication for employees 

who are potentially exposed to respirable crystalline silica. Many of 

the proposed requirements are already required by OSHA’s Hazard 

Communication Standard. The Agency requests comment on the 

proposed requirements in Section I. Issues (See Provisions of the 

Standards—Hazard communication). 

(Construction) The Panel recommended that OSHA carefully review the 

recordkeeping requirements with respect to both their utility and burden.

OSHA has reviewed the recordkeeping requirements as required by 

the Paperwork Reduction Act. Detailed analysis of the recordkeeping 

requirements can be found in OSHA’s information collection request 

submitted to OMB. 

The recordkeeping requirements are discussed in the Summary and 

Explanation for paragraph (j) Recordkeeping. OSHA solicits comment on these requirements in Section I. Issues (See Provisions of 

the Standards—Recordkeeping). 

The Panel recommended that OSHA, to the extent permitted by the 

availability of economic data, update economic data to better reflect 

recent changes in the economic status of the affected industries consistent with its statutory mandate.

OSHA has prepared the PEA using the most current economic data 

available. 

SERs in construction, and some in general industry, felt the estimate of 

affected small entities and employees did not give adequate consideration to workers who would be subject to exposure at a site but 

were not directly employed by firms engaged in silica-associated 

work, such as employees of other subcontractors at a construction 

site, visitors to a plant, etc.

The scope of the proposed standard is discussed in the Summary and 

Explanation for paragraph (a) Scope and Application. 

The Panel recommended that OSHA carefully examine this issue, considering both the possible costs associated with such workers, and 

ways of clarifying what workers are covered by the standard 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56433 

TABLE VIII–33—SBREFA PANEL RECOMMENDATIONS AND OSHA RESPONSES—Continued 

SBREFA Panel recommendation OSHA response 

The Panel recommended that OSHA clarify in any rulemaking action 

how its action is or is not related to designating silica-containing materials as hazardous wastes.

The relationship between the proposed rule and EPA requirements is 

discussed in Section XVI, Environmental Impacts. 

Some SERs also noted the issue that the use of wet methods in some 

areas may violate EPA rules with respect to suspended solids in runoff unless provision is made for recycling or settling the suspended 

solids out of the water.

The Panel recommended that OSHA investigate this issue, add appropriate costs if necessary, and solicit comment on this issue.

Silica wastes are not classified as hazardous. Therefore OSHA believes that the incremental disposal costs resulting from dust collected in vacuums and other sources are likely to be quite small. An 

analysis of wet methods for dust controls suggests that in most 

cases the amount of slurry discharged are not sufficient to cause a 

run off to storm drains. OSHA solicits comments on this topic in Section I. Issues (See Environmental Impacts). 

The Panel recommended that OSHA (1) carefully consider and solicit 

comment on the alternative of improved outreach and support for the 

existing standard; (2) examine what has and has not been accomplished by existing outreach and enforcement efforts; and (3) examine and fully discuss the need for a new standard and if such a 

standard can accomplish more than improved outreach and enforcement.

A review of OSHA’s outreach efforts is provided in Section III, Events 

Leading to the Proposed Standards. OSHA solicits comment on this 

topic in Section I. Issues (See Alternatives/Ways to Simplify a New 

Standard). 

The Panel recommended, if there is to be a standard for construction, 

that OSHA: (1) seek ways to greatly simplify the standard and restrict the number of persons in respirators; (2) consider the alternative of a standard oriented to engineering controls and work practices in construction; and (3) analyze and solicit comment on ways to 

simplify the standard.

OSHA has made a preliminary determination that compliance with the 

proposed PEL can be achieved in most operations most of the time 

through the use of engineering and work practice controls. However, 

as described in the Summary and Explanation of paragraphs (f) 

Methods of Compliance and (g) Respiratory Protection and in the 

Technological Feasibility chapter of the PEA, use of respiratory protection will be required for some operations. OSHA solicits comment 

on this topic in Section I. Issues (See Technological and Economic 

Feasibility of the Proposed PEL). OSHA also solicits comment on 

ways to simplify the standard in Section I. Issues (See Alternatives/

Ways to Simplify a New Standard). 

The Panel recommended that, if there is to be a standard, OSHA consider and solicit comment on maintaining the existing PEL. The 

Panel also recommends that OSHA examine each of the ancillary 

provisions on a provision-by-provision basis in light of the comments 

of the SERs on the costs and lack of need for some of these provisions.

As discussed in the Summary and Explanation for paragraph (c) Permissible Exposure Limit (PEL), OSHA has made a preliminary determination that the proposed PEL is necessary to meet the legal requirements to reduce significant risk to the extent feasible. Because 

the proposed PEL is a fixed value, OSHA also believes it is easier to 

understand when compared to the current PEL. OSHA solicits comment on the proposed PEL in Section I. Issues (See Provisions of 

the Standards—PEL and action level). 

(General Industry) The Panel recommended that OSHA carefully examine the technological and economic feasibility of the draft proposed 

standard in light of these SER comments.

The PEA reflects OSHA’s judgment on the technological and economic 

feasibility of the proposed standard and includes responses to specific issues raised by the Panel. OSHA solicits comment on the accuracy and reasonableness of these judgments in Section I. Issues 

(See Technological and Economic Feasibility of the Proposed PEL). 

(General Industry) Some SERs were concerned that the prohibition on 

dry sweeping was not feasible or cost effective in their industries.

The Panel recommended that OSHA consider this issue and solicit 

comment on the costs and necessity of such a prohibition.

OSHA has proposed to limit the prohibition on dry sweeping to situations where this activity could contribute to exposure that exceeds 

the PEL. The Agency solicits comment on this topic in Section I. 

Issues (See Provisions of the Standards—Methods of compliance). 

(General Industry) The Panel recommended that OSHA carefully consider whether regulated area provisions should be included in the 

draft proposed standard, and, if so, where and how regulated areas 

are to be established. OSHA should also clarify in the preamble and 

in its compliance assistance materials how compliance is expected to 

be achieved in the various circumstances raised by the SERs.

Proposed regulated area provisions are explained in the Summary and 

Explanation for paragraph (e) Regulated Areas and Access Control. 

The proposed standard also includes a provision for implementation 

of ‘‘access control plans’’ in lieu of establishing regulated areas. 

Clarification for establishing an access control plan is provided in the 

Summary and Explanation. 

(General Industry) The Panel recommended that OSHA carefully examine the issues associated with reliability of monitoring and laboratory 

standards in light of the SER comments, and solicit comment on 

these issues.

OSHA has made a preliminary determination in the proposed rule that 

only certain sampling and analytical methods can be used to measure airborne crystalline silica at the proposed PEL. Issues related to 

sampling and analytical methods are discussed in the Technological 

Feasibility section of the PEA. OSHA solicits comment on the Agency’s preliminary determination in Section I. Issues (See Provisions of 

the Standards—Exposure Assessment). 

(General Industry) Some SERs preferred the more performance-oriented Option 2 provision included in the draft exposure assessment 

requirements, stating that fixed-frequency exposure monitoring can 

be unnecessary and wasteful. However, other SERs expressed concern over whether such a performance-oriented approach would be 

consistently interpreted by enforcement officers.

The Panel recommended that OSHA continue to consider Option 2 but, 

should OSHA decide to include it in a proposed rule, clarify what 

would constitute compliance with the provision. Some SERs were 

also concerned about the wording of the exposure assessment provision.

The proposed standard provides two options for periodic exposure assessment; (1) a fixed schedule option, and (2) a performance option. 

The performance option provides employers flexibility in the methods 

used to determine employee exposures, but requires employers to 

accurately characterize employee exposures. The proposed approach is explained in the Summary and Explanation for paragraph 

(d) Exposure Assessment. OSHA solicits comments on the proposed 

exposure assessment provision in Section I. Issues (See Provisions 

of the Standards—Exposure Assessment). 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56434 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE VIII–33—SBREFA PANEL RECOMMENDATIONS AND OSHA RESPONSES—Continued 

SBREFA Panel recommendation OSHA response 

(General Industry) Some SERs were also concerned about the wording 

of the exposure assessment provision of the draft proposed standard. These SERs felt that the wording could be taken to mean that 

an employer needed to perform initial assessments annually.

The Panel recommended that OSHA clarify this issue. The requirement for initial exposure assessment is clarified in the Summary and Explanation of paragraph (d) Exposure Assessment. The 

term ‘‘initial’’ indicates that this is the first action required to assess 

exposure and is required only once. 

(General Industry) While some SERs currently provide both protective 

clothing and hygiene facilities, others provide neither. Those SERs 

that do not currently provide either felt that these provisions were 

both highly expensive and unnecessary. Some SERs stated that 

these provisions were pointless because silica is not a take-home 

hazard or a dermal hazard. Others suggested that such provisions 

only be required when the PEL is exceeded.

The Panel recommended that OSHA carefully consider the need for 

these provisions, and solicit comment on the need for these provisions, and how they might be limited.

As described in the Summary and Explanation for paragraph (e) Regulated Areas and Access Control, OSHA has proposed a limited requirement for use of protective clothing or other means to remove 

silica dust from contaminated clothing. This requirement would apply 

only in regulated areas where there is the potential for work clothing 

to become grossly contaminated with silica dust. No requirement for 

hygiene facilities is included in the proposed standard. OSHA solicits 

comment regarding appropriate requirements for use of protective 

clothing and hygiene facilities in Section I. Issues (See Provisions of 

the Standards—Regulated areas and access control). 

(General Industry) The SER comments included several suggestions 

regarding the nature and wording of the health screening requirements. (See, e.g., OSHA, 2003, pp. 25–28.).

The Panel recommended that OSHA consider revising the standard in 

light of these comments, as appropriate.

OSHA has considered these comments and revised the proposed 

standard where appropriate. The revisions are discussed in the Summary and Explanation of paragraph (n) Medical Surveillance. 

(General Industry) The Panel recommended that OSHA explicitly examine and report on the availability of specialists called for by these 

provisions, and re-examine the costs and feasibility of such requirements based on their findings with respect to availability, as needed.

The provisions requiring B-readers and pulmonary specialists are discussed in the Summary and Explanation of paragraph (n) Medical 

Surveillance, and the numbers of available specialists are reported. 

OSHA solicits comment on this topic in Section I. Issues (See Provisions of the Standards—Medical surveillance). 

(General Industry) Though the provision for hazard communication simply repeats such provisions already in existence, some SERs urged 

OSHA to use this opportunity to change the requirement so that 

warning labels would only be required of substances that were more 

than 1% (rather than the current 0.1%) by weight of silica.

OSHA has preliminarily determined to rely on the provisions of the 

Hazard Communication Standard (HCS) in the proposed rule. The 

HCS requires labels for mixtures that contain more than 0.1% of a 

carcinogen. OSHA solicits comment on this topic in Section I. Issues 

(See Provisions of the Standards—Medical surveillance). 

The Panel recommended that OSHA consider this suggestion and solicit comment on it. 

(General Industry) The Panel recommended that OSHA carefully review the recordkeeping requirements with respect to both their utility 

and burden.

The recordkeeping requirements are discussed in the Summary and 

Explanation for paragraph (j) Recordkeeping. OSHA solicits comment on these requirements in Section I. Issues (See Provisions of 

the Standards—Recordkeeping). 

(Construction) The Panel recommended that OSHA continue to evaluate the appropriateness of and consider modifications to scope Option 2 that can more readily serve to limit the scope of the standard.OSHA has made the preliminary determination that scope Option 1 is 

most appropriate. OSHA solicits comment on this subject in Section 

I. Issues (See Provisions of the Standards—Scope). 

(Construction) Many SERs found the requirements for a competent 

person hard to understand. Many SERs took the competent person 

requirement as requiring a person with a high level of skills, such as 

the ability to conduct monitoring. Other SERs said this requirement 

would require training a high percentage of their employees as competent persons because they typically had many very small crews at 

many sites. In general, the SERs thought this requirement as written 

would be difficult to comply with and costly.

The standard requires a competent person only in limited circumstances when an employer selects the option to implement an 

‘‘access control plan’’ in lieu of establishing a regulated area. Further 

clarification is provided in the Summary and Explanation of paragraph (e) Regulated Areas and Access Control. 

The Panel recommended that OSHA seek ways to clarify OSHA’s intent with respect to this requirement and more clearly delineate the 

responsibilities of competent persons. 

(Construction) Many SERs did not understand that Table 1 was offered 

as an alternative to exposure assessment and demonstration that the 

PEL is being met. Some SERs, however, understood the approach 

and felt that it had merit. These SERs raised several issues concerning the use of Table 1, including:.

• The Table should be expanded to include all construction activities 

covered by the standard, or the scope of the standard should be reduced to only those activities covered by Table 1; 

• The control measures endorsed in Table 1 need to be better established, as necessary; and 

• Table 1 should require less use of, and possibly no use of, respirators.

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56435 

TABLE VIII–33—SBREFA PANEL RECOMMENDATIONS AND OSHA RESPONSES—Continued 

SBREFA Panel recommendation OSHA response 

The Panel recommended that OSHA carefully consider these suggestions, expand Table 1, and make other modifications, as appropriate The rationale for the operations and control measures to be included in 

Table 1 is provided in the Summary and Explanation for paragraph 

(f) Methods of Compliance. Table 1 includes some operations for 

which it is anticipated that even with the implementation of control 

measures, exposure levels will routinely exceed the proposed PEL, 

and thus reliance on the use of respiratory protection is appropriate. 

Table 1 has been modified to limit requirements for respirator use 

where operations are performed for less than 4 hours per day. 

OSHA solicits comment on the proposed requirements in Section I. 

Issues (See Provisions of the Standards—Methods of compliance). 

The Panel recommends that OSHA thoroughly review the economic 

impacts of compliance with a proposed silica standard and develop 

more detailed feasibility analyses where appropriate..

OSHA significantly expanded its economic impact and economic feasibility analyses in Chapter VI of the PEA. As part of the impact analysis, OSHA added data on normal year-to-year variations in prices 

and profit rates in affected industries to provide a context for evaluating potential price and profit impacts of the proposed rule. A section was also added to estimate the potential international trade impacts of the proposed rule. OSHA solicits comments in Chapter VI of 

the PEA on the issues of the economic impacts and the economic 

feasibility of the proposed rule. 

(Construction) The panel recommends that OSHA re-examine its cost 

estimates for respirators to make sure that the full cost of putting employees in respirators is considered.

OSHA re-examined and updated its cost estimates for each type of 

respirator. Unit respirator costs included the cost of the respirator 

itself and the annualized cost of respirator use, to include accessories (e.g., filters), training, fit testing, and cleaning. All costs were 

updated to 2009 dollars. In addition, OSHA added a cost for employers to establish a respirator program. OSHA solicits comments on 

this issue in Chapter V of the PEA. 

(Construction) Some SERs indicated that the unit costs were underestimated for monitoring, similar to the general industry issues raised 

previously. In addition, special issues for construction were raised 

(i.e., unpredictability of exposures), suggesting the rule would be 

costly, if not impossible to comply with.

The Panel recommends that OSHA carefully review the basis for its estimated compliance costs, consider the concerns raised by the 

SERs, and ensure that its estimates are revised, as appropriate, to 

fully reflect the costs likely to be incurred by potentially affected establishments.

To reflect the fact that an industrial hygienist could not typically take as 

many samples a day in a small establishment as in a large one, 

OSHA developed cost estimates for exposure monitoring as a function of the size of the establishment. OSHA’s cost estimates therefore now reflect the fact that smaller entities will tend to experience 

larger unit costs for exposure monitoring. 

To reflect possible problems of unpredictability of exposure in construction, Table 1 in the proposed standard has been designed to allow 

establishments in construction the option, for certain operations, to 

implement engineering controls, work practices, and respiratory protection without the need for exposure assessment. 

OSHA has carefully reviewed the basis for its exposure monitoring cost 

estimates and considered the concerns raised by the SERs. OSHA 

solicits comments on this issue in Chapter V of the PEA. 

(General Industry) The Panel recommends that OSHA use the best scientific evidence and methods available to determine the significance 

of risks and magnitude of benefits for occupational exposure to silica. 

The Panel further recommends that OSHA evaluate existing state silicosis surveillance data to determine whether there are industry-specific differences in silicosis risks, and whether or how the draft standard should be revised to reflect such differences.

OSHA has conducted a comprehensive review of the scientific evidence from toxicological and epidemiological studies on adverse 

health effects associated with occupational exposure to respirable 

crystalline silica. This review is summarized in Section V of this preamble, Health Effects Summary, and estimates of the risks of developing silica-related diseases are summarized in Section VI, Summary of the Preliminary Quantitative Risk Assessment. The significance of these risks is examined in Section VII, Significance of Risk. 

The benefits associated with the proposed rule are summarized in 

Section VIII.G, Benefits and Net Benefits. Although OSHA’s preliminary analysis indicates that a variety of factors may affect the 

toxicologic potency of crystalline silica found in different work environments, OSHA has not identified information that would allow the 

Agency to calculate how these influences may affect disease risk to 

workers in any particular workplace setting. 

The SERs, however, also had many specific issues concerning what 

OSHA should do if it chooses to go forward with a proposed rule. In 

order to reflect these specific issues, the Panel has made many recommendations concerning issues to be considered if the Agency 

goes forward with a rule. The Panel also recommends that OSHA 

take great care in reviewing and considering all comments made by 

the SERs.

OSHA has carefully considered the Panel recommendations, and the 

Agency’s responses are listed in this table. In addition, specific 

issues raised in comments by individual SERs are addressed 

throughout the preamble. 

IX. OMB Review Under the Paperwork 

Reduction Act of 1995 

A. Overview 

The proposed general industry/

maritime and construction standards 

(‘‘the standards’’) for respirable 

crystalline silica contain collection of 

information (paperwork) requirements 

that are subject to review by the Office 

of Management and Budget (OMB) 

under the Paperwork Reduction Act of 

1995 (PRA–95), 44 U.S.C. 3501 et seq, 

and OMB’s regulations at 5 CFR part 

1320. PRA–95 defines ‘‘collection of 

information’’ to mean, ‘‘the obtaining, 

causing to be obtained, soliciting, or 

requiring the disclosure to third parties 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56436 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

or the public, of facts or opinions by or 

for an agency, regardless of form or 

format’’ (44 U.S.C. 3502(3)(A)). Under 

PRA–95, a Federal agency cannot 

conduct or sponsor a collection of 

information unless OMB approves it, 

and the agency displays a currently 

valid OMB control number. 

B. Solicitation of Comments 

OSHA prepared and submitted an 

Information Collection Request (ICR) for 

the collection of information 

requirements identified in this NPRM to 

OMB for review in accordance with 44 

U.S.C. 3507(d). The Agency solicits 

comments on the proposed new 

collection of information requirements 

and the estimated burden hours 

associated with these requirements, 

including comments on the following 

items: 

• Whether the proposed collection of 

information requirements are necessary 

for the proper performance of the 

Agency’s functions, including whether 

the information is useful; 

• The accuracy of OSHA’s estimate of 

the burden (time and cost) of the 

information collection requirements, 

including the validity of the 

methodology and assumptions used; 

• The quality, utility and clarity of 

the information collected; and 

• Ways to minimize the compliance 

burden on employers, for example, by 

using automated or other technological 

techniques for collecting and 

transmitting information. 

C. Proposed Revisions to Information 

Collection Requirements 

As required by 5 CFR 1320.5(a)(1)(iv) 

and 1320.8(d)(2), the following 

paragraphs provide information about 

this ICR. 

1. Title: Respirable Crystalline Silica 

Standards for General Industry/

Maritime (§ 1910.1053) and 

Construction (§ 1926.1053) 

2. Description of the ICR: The 

proposed respirable crystalline silica 

standards contain collection of 

information requirements which are 

essential components of the 

occupational safety and health 

standards that will assist both 

employers and their employees in 

identifying exposures to crystalline 

silica, the medical effects of such 

exposures, and means to reduce or 

eliminate respirable crystalline silica 

overexposures. 

3. Summary of the Collections of 

Information: 

1910.1053(d) and 1926.1053(d)— 

Exposure Assessment 

Under paragraph (d)(6) of the 

proposed rule, employers covered by 

the general industry/maritime standard 

must notify each affected employee 

within 15 working days of completing 

an exposure assessment. In 

construction, employers must notify 

each affected employee not more than 5 

working days after completing the 

exposure assessment. In these 

standards, the following provisions 

require exposure assessment 

monitoring: § 1910.1053(d)(1) and 

§ 1926.1053(d)(1), General; 

§ 1910.1053(d)(2) and § 1926.1053(d)(2), 

Initial Exposure Assessment; 

§ 1910.1053(d)(3) and § 1926.1053(d)(3), 

Periodic Exposure Assessments; 

§ 1910.1053 (d)(4) and 

§ 1926.1053(d)(4), Additional Exposure 

Assessments; and § 1926.1053(d)(8)(ii), 

Specific Operations. 

Under § 1910.1053(d)(6)(i) and 

§ 1926.1053(d)(6)(i), employers must 

either notify each affected employee in 

writing or post the monitoring results in 

an appropriate location accessible to all 

affected employees. In addition, 

paragraph (d)(6)(ii) of § 1910.1053 and 

§ 1926.1053 require that whenever the 

employer exceeds the permissible 

exposure limit (PEL), the written 

notification must contain a description 

of the corrective action(s) the employer 

is taking to reduce employee exposures 

to or below the PEL. 

1910.1053(e)(3) and 1926.1053(e)(3)— 

Written Access Control Plan 

The standard provides employers 

with the option to develop and 

implement a written access control plan 

in lieu of establishing regulated areas 

under paragraph (e)(3). Paragraph 

(e)(3)(ii) sets out the requirements for a 

written access control plan. The plan 

must contain provisions for a competent 

person to identify the presence and 

location of any areas where respirable 

crystalline silica exposures are, or can 

reasonably be expected to be, in excess 

of the PEL. It must describe how the 

employer will notify employees of the 

presence and location of areas where 

exposures are, or can reasonably be 

expected to be, in excess of the PEL, and 

how the employer will demarcate these 

areas from the rest of the workplace. For 

multi-employer workplaces, the plan 

must identify the methods the 

employers will use to inform other 

employers of the presence, and the 

location, of areas where respirable 

crystalline silica exposures may exceed 

the PEL, and any precautionary 

measures the employers need to take to 

protect employees. The written plan 

must contain provisions for restricting 

access to these areas to minimize the 

number of employees exposed, and the 

level of employee exposure. The plan 

also must describe procedures for 

providing each employee entering areas 

where respirable crystalline silica 

exposures may exceed the PEL, with an 

appropriate respirator in accordance 

with paragraph (g) of the proposed rule; 

the employer also must provide this 

information to the employee’s 

designated representative. Additionally, 

where there is the potential for 

employees’ work clothing to become 

grossly contaminated with finely 

divided material containing crystalline 

silica, the plan must include provisions 

for the employer to provide either 

appropriate protective clothing or other 

means to remove excessive silica dust 

from contaminated clothing, as well as 

provisions for the removal or cleaning of 

such clothing. 

The employer must review and 

evaluate the effectiveness of the written 

access control plan at least annually, 

and update it as necessary. The written 

access control plan must be available for 

examination and copying, upon request, 

to employees, their designated 

representatives, the Assistant Secretary, 

and the Director. 

1910.1053(f)—Methods of Compliance 

Where the employer conducts 

abrasive blasting operations, paragraph 

(f)(2) in the general industry/maritime 

standard requires the employer to 

comply with the requirements of 29 CFR 

part 1915, subpart I (Personal Protective 

Equipment), as applicable. Subpart I 

contains several information collection 

requirements. Under subpart I, when 

conducting hazard assessments, the 

employer must: (1) Select the type of 

personal protective equipment (PPE) 

that will protect the affected employee 

from the hazards identified in the 

occupational hazard assessment; (2) 

communicate selection decisions to 

affected employees; (3) select PPE that 

properly fits each affected employee; 

and (4) verify that the required 

occupational hazard assessment has 

been performed. Additionally, subpart I 

requires employers to provide training 

and verification of training for each 

employee required to wear PPE. 

1910.1053(g) and 1926.1053(g)— 

Respiratory Protection 

Paragraph (g) in the standards 

requires the employer to institute a 

respiratory protection program in 

accordance with 29 CFR 1910.134. The 

Respiratory Protection Standard’s 

information collection requirements 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56437 

provide that employers must: develop a 

written respirator program; obtain and 

maintain employee medical evaluation 

records; provide the physician or other 

licensed health care professional 

(PLHCP) with information about the 

employee’s respirator and the 

conditions under which the employee 

will use the respirator; administer fit 

tests for employees who will use 

negative- or positive-pressure, tightfitting facepieces; and establish and 

retain written information regarding 

medical evaluations, fit testing, and the 

respirator program. 

1910.1053(h) and 1926.1053(h)— 

Medical Surveillance 

Paragraph (h)(2) in the standards 

requires employers to make available to 

covered employees an initial medical 

examination within 30 days after initial 

assignment unless the employee 

received a medical examination 

provided in accordance with the 

standard within the past three years. 

Proposed paragraphs (h)(2)(i)–(vi) 

specify that the baseline medical 

examination provided by the PLHCP 

must consist of the following 

information: 

1. A medical and work history, with 

emphasis on: past, present, and 

anticipated exposure to respirable 

crystalline silica, dust, and other agents 

affecting the respiratory system; any 

history of respiratory system 

dysfunction, including signs and 

symptoms of respiratory disease; history 

of tuberculosis; and smoking status and 

history; 

2. A physical examination with 

special emphasis on the respiratory 

system; 

3. A chest X-ray interpreted and 

classified according to the International 

Labour Organization International 

Classification of Radiographs of 

Pneumoconioses by a National Institute 

for Occupational Safety and Health 

(NIOSH)-certified ‘‘B’’ reader, or an 

equivalent diagnostic study; 

4. A pulmonary function test 

administered by a spirometry technician 

with current certification from a NIOSHapproved spirometry course; 

5. Testing for latent tuberculosis 

infection; and 

6. Any other tests deemed appropriate 

by the PLHCP. 

Paragraph (h)(3) in the standards 

requires periodic medical examinations 

administered by a PLHCP, every three 

years or more frequently if 

recommended by the PLHCP, for 

covered employees, including medical 

and work history, physical examination 

emphasizing the respiratory system, 

chest X-rays or equivalent diagnostic 

study, pulmonary function tests, and 

other tests deemed to be appropriate by 

the PLHCP. 

Paragraph (h)(4) in the standards 

requires the employer to provide the 

examining PLHCP with a copy of the 

standard. In addition, for each employee 

receiving a medical examination, the 

employer must provide the PLHCP with 

the following information: a description 

of the affected employee’s former, 

current, and anticipated duties as they 

relate to the employee’s occupational 

exposure to respirable crystalline silica; 

the employee’s former, current, and 

anticipated levels of occupational 

exposure to respirable crystalline silica; 

a description of any PPE used or to be 

used by the employee, including when 

and for how long the employee has used 

that equipment; and information from 

records of employment-related medical 

examinations previously provided to the 

affected employee and currently within 

the control of the employer. 

Paragraph (h)(5) in the standards 

requires the employer to obtain a 

written medical opinion from the 

PLHCP within 30 days of each medical 

examination performed on each 

employee. The employer must provide 

the employee with a copy the PLHCPs’ 

written medical opinion within two 

weeks of receipt. This written opinion 

must contain the following information: 

1. A description of the employee’s 

health condition as it relates to exposure 

to respirable crystalline silica, including 

the PLHCP’s opinion as to whether the 

employee has any detected medical 

condition(s) that would place the 

employee at increased risk of material 

impairment to health from exposure to 

respirable crystalline silica; 

2. Any recommended limitations 

upon the employee’s exposure to 

respirable crystalline silica or on the use 

of PPE such as respirators; 

3. A statement that the employee 

should be examined by an American 

Board Certified Specialist in Pulmonary 

Disease (‘‘pulmonary specialist’’) 

pursuant to paragraph (h)(6) if the ‘‘B’’ 

reader classifies the chest X-ray as 1/0 

or higher, or if referral to a pulmonary 

specialist is otherwise deemed 

appropriate by the PLHCP; and 

4. A statement that the PLHCP 

explained to the employee the results of 

the medical examination, including 

findings of any medical conditions 

related to respirable crystalline silica 

exposure that require further evaluation 

or treatment, and any recommendations 

related to use of protective clothing or 

equipment. 

If the PLHCP’s written medical 

opinion indicates that a pulmonary 

specialist should examine an employee, 

paragraph (h)(6) in the standards 

requires the employer to make available 

for the employee a medical examination 

by a pulmonary specialist within 30 

days after receiving the PLHCP’s written 

medical opinion. The employer must 

provide the examining pulmonary 

specialist with information specified by 

paragraph (h)(4). The employer must 

obtain a written opinion from the 

pulmonary specialist within 30 days of 

the examination. The written opinion 

must be comparable to the written 

opinion obtained from the original 

PLHCP. The pulmonary specialist also 

must state in the written opinion that 

the specialist explained these findings 

to the employee. The employer also 

must provide a copy of the PLHCP’s 

written medical opinion to the 

examined employee within two weeks 

after receiving it. 

1910.1053(i) and 1926.1053(i)— 

Communication of Respirable 

Crystalline Silica Hazards to Employees 

Paragraph (i)(1) of the standards 

requires compliance with the Hazard 

Communication Standard (29 CFR 

1910.1200), and lists cancer, lung 

effects, immune system effects, and 

kidney effects as hazards that the 

employer must address in its hazard 

communication program. Additionally, 

employers must ensure that each 

employee has access to labels on 

containers of crystalline silica and 

safety data sheets. Under paragraph 

(i)(2)(ii), the employer must make a 

copy of this section readily available 

without cost to each affected employee. 

1910.1053(j) and 1926.1053(j)— 

Recordkeeping 

Paragraph (j)(1)(i) of the standards 

requires that employers maintain an 

accurate record of all employee 

exposure measurement results as 

prescribed in paragraph (d) of these 

standards. The record must include the 

following information: the date of 

measurement for each sample taken; the 

operation monitored; sampling and 

analytical methods used; number, 

duration, and results of samples taken; 

identity of the laboratory that performed 

the analysis; type of PPE, such as 

respirators, worn by the employees 

monitored; and the name, social 

security number, and job classification 

of all employees represented by the 

monitoring, indicating which employees 

were monitored. The employer must 

maintain, and make available, employee 

exposure records in accordance with 29 

CFR 1910.1020. 

Paragraph (j)(2)(i) requires the 

employer to maintain an accurate record 

of all objective data relied on to comply 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56438 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

with the proposed requirements of this 

section. The record must include the 

following information: the crystalline 

silica-containing material in question; 

the source of the objective data; the 

testing protocol and results of testing; 

and a description of the process, 

operation, or activity, and how the data 

support the assessment; and other data 

relevant to the process, operation, 

activity, material, or employee 

exposures. The employer must 

maintain, and make available, the 

objective data records in accordance 

with 29 CFR 1910.1020. 

Paragraph (j)(3)(i) requires the 

employer to establish and maintain an 

accurate record for each employee 

covered by medical surveillance under 

paragraph (h). The record must include 

the following information: the 

employee’s name and social security 

number; a copy of the PLHCP’s and 

pulmonary specialist’s written opinions; 

and a copy of the information provided 

to the PLHCP and pulmonary specialist 

as required by paragraph (h)(4) of the 

proposed rule. The employer must 

maintain, and make available, the 

medical surveillance records in 

accordance with 29 CFR 1910.1020. 

4. Number of respondents: Employers 

in general industry, maritime, or 

construction that have employees 

working in jobs affected by respirable 

crystalline silica exposure (543,041 

businesses). 

5. Frequency of responses: Frequency 

of response varies depending on the 

specific collection of information. 

6. Number of responses: 4,242,296. 

7. Average time per response: Varies 

from 5 minutes (.08 hour) for the 

employer to provide a copy of the 

written physician’s opinion to the 

employee, to 8 hours to establish a new 

respiratory protection program in large 

establishments. 

8. Estimated total burden hours: 

2,585,164. 

9. Estimated costs (capital-operation 

and maintenance): $273,504,281. 

D. Submitting Comments 

Members of the public who wish to 

comment on the paperwork 

requirements in this proposal must send 

their written comments to the Office of 

Information and Regulatory Affairs, 

Attn: OMB Desk Officer for the 

Department of Labor, OSHA (RIN–1218 

–AB70), Office of Management and 

Budget, Room 10235, Washington, DC 

20503, Telephone: 202–395–6929/Fax: 

202–395–6881 (these are not toll-free 

numbers), email: OIRA_submission@

omb.eop.gov. The Agency encourages 

commenters also to submit their 

comments on these paperwork 

requirements to the rulemaking docket 

(Docket Number OSHA–2010–0034), 

along with their comments on other 

parts of the proposed rule. For 

instructions on submitting these 

comments to the rulemaking docket, see 

the sections of this Federal Register 

notice titled DATES and ADDRESSES. 

Comments submitted in response to this 

notice are public records; therefore, 

OSHA cautions commenters about 

submitting personal information such as 

Social Security numbers and date of 

birth. 

E. Docket and Inquiries 

To access the docket to read or 

download comments and other 

materials related to this paperwork 

determination, including the complete 

Information Collection Request (ICR) 

(containing the Supporting Statement 

with attachments describing the 

paperwork determinations in detail) use 

the procedures described under the 

section of this notice titled ADDRESSES. 

You also may obtain an electronic copy 

of the complete ICR by visiting the Web 

page at http://www.reginfo.gov/public/

do/PRAMain, scroll under ‘‘Currently 

Under Review’’ to ‘‘Department of Labor 

(DOL)’’ to view all of the DOL’s ICRs, 

including those ICRs submitted for 

proposed rulemakings. To make 

inquiries, or to request other 

information, contact Mr. Todd Owen, 

Directorate of Standards and Guidance, 

OSHA, Room N–3609, U.S. Department 

of Labor, 200 Constitution Avenue NW., 

Washington, DC 20210; telephone (202) 

693–2222. 

OSHA notes that a federal agency 

cannot conduct or sponsor a collection 

of information unless it is approved by 

OMB under the PRA and displays a 

currently valid OMB control number, 

and the public is not required to 

respond to a collection of information 

unless the collection of information 

displays a currently valid OMB control 

number. Also, notwithstanding any 

other provision of law, no person shall 

be subject to penalty for failing to 

comply with a collection of information 

if the collection of information does not 

display a currently valid OMB control 

number. 

X. Federalism 

The Agency reviewed the proposed 

crystalline silica rule according to the 

Executive Order on Federalism 

(Executive Order 13132, 64 FR 43255, 

Aug. 10, 1999), which requires that 

Federal agencies, to the extent possible, 

refrain from limiting State policy 

options, consult with States before 

taking actions that would restrict States’ 

policy options and take such actions 

only when clear constitutional authority 

exists and the problem is of national 

scope. The Executive Order allows 

Federal agencies to preempt State law 

only with the expressed consent of 

Congress; in such cases, Federal 

agencies must limit preemption of State 

law to the extent possible. 

Under Section 18 of the Occupational 

Safety and Health Act (the ‘‘Act’’’ or 

‘‘OSH Act,’’ 29 U.S.C. 667), Congress 

expressly provides that States may 

adopt, with Federal approval, a plan for 

the development and enforcement of 

occupational safety and health 

standards; States that obtain Federal 

approval for such a plan are referred to 

as ‘‘State-Plan States.’’ (29 U.S.C. 667). 

Occupational safety and health 

standards developed by State-Plan 

States must be at least as effective in 

providing safe and healthful 

employment and places of employment 

as the Federal standards. Subject to 

these requirements, State-Plan States are 

free to develop and enforce their own 

requirements for occupational safety 

and health standards. 

While OSHA drafted the proposed 

rule to protect employees in every State, 

Section 18(c)(2) of the OSHA Act 

permits State-Plan States to develop and 

enforce their own standards, provided 

the requirements in these standards are 

at least as safe and healthful as the 

requirements specified in the proposed 

rule if it is promulgated. 

In summary, the proposed rule 

complies with Executive Order 13132. 

In States without OSHA-approved State 

plans, Congress expressly provides for 

OSHA standards to preempt State 

occupational safety and health 

standards in areas addressed by the 

Federal standards; in these States, this 

rule limits State policy options in the 

same manner as every standard 

promulgated by the Agency. In States 

with OSHA-approved State plans, this 

rulemaking does not significantly limit 

State policy options. 

XI. State-Plan States 

When Federal OSHA promulgates a 

new standard or a more stringent 

amendment to an existing standard, the 

27 State and U.S. territories with their 

own OSHA-approved occupational 

safety and health plans (‘‘State-Plan 

States’’) must revise their standards to 

reflect the new standard or amendment. 

The State standard must be at least as 

effective as the Federal standard or 

amendment, and must be promulgated 

within six months of the publication 

date of the final Federal rule. 29 CFR 

1953.5(a). 

The State may demonstrate that a 

standard change is not necessary 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56439 

because, for example, the State standard 

is already the same as or at least as 

effective as the Federal standard change. 

In order to avoid delays in worker 

protection, the effective date of the State 

standard and any of its delayed 

provisions must be the date of State 

promulgation or the Federal effective 

date, whichever is later. The Assistant 

Secretary may permit a longer time 

period if the State makes a timely 

demonstration that good cause exists for 

extending the time limitation. 29 CFR 

1953.5(a). 

Of the 27 States and territories with 

OSHA-approved State plans, 22 cover 

public and private-sector employees: 

Alaska, Arizona, California, Hawaii, 

Indiana, Iowa, Kentucky, Maryland, 

Michigan, Minnesota, Nevada, New 

Mexico, North Carolina, Oregon, Puerto 

Rico, South Carolina, Tennessee, Utah, 

Vermont, Virginia, Washington, and 

Wyoming. The five states and territories 

whose OSHA-approved State plans 

cover only public-sector employees are: 

Connecticut, Illinois, New Jersey, New 

York, and the Virgin Islands. 

This proposed crystalline silica rule 

applies to general industry, construction 

and maritime, and would impose 

additional or more stringent 

requirements. If adopted as proposed, 

all State Plan States would be required 

to revise their general industry and 

construction standards appropriately 

within six months of Federal 

promulgation. In addition, State plans 

that cover private sector maritime 

employment issues and/or have public 

employees working in the maritime 

industry covered by this standard would 

be required to adopt comparable 

provisions to their maritime 

employment standards within six 

months of publication of the final rule. 

XII. Unfunded Mandates 

Under Section 202 of the Unfunded 

Mandates Reform Act of 1995 (UMRA), 

2 U.S.C. 1532, an agency must prepare 

a written ‘‘qualitative and quantitative 

assessment’’ of any regulation creating a 

mandate that ‘‘may result in the 

expenditure by the State, local, and 

tribal governments, in the aggregate, or 

by the private sector, of $100,000,000 or 

more’’ in any one year before issuing a 

notice of proposed rulemaking. OSHA’s 

proposal does not place a mandate on 

State or local governments, for purposes 

of the UMRA, because OSHA cannot 

enforce its regulations or standards on 

State or local governments. (See 29 

U.S.C. 652(5).) Under voluntary 

agreement with OSHA, some States 

enforce compliance with their State 

standards on public sector entities, and 

these agreements specify that these State 

standards must be equivalent to OSHA 

standards. The OSH Act also does not 

cover tribal governments in the 

performance of traditional governmental 

functions, though it does when tribal 

governments engage in commercial 

activity. However, the proposal would 

not require tribal governments to 

expend, in the aggregate, $100,000,000 

or more in any one year for their 

commercial activities. Thus, although 

OSHA may include compliance costs for 

affected governmental entities in its 

analysis of the expected impacts 

associated with a proposal, the proposal 

does not trigger the requirements of 

UMRA based on its impact on State, 

local, or tribal governments. 

Based on the analysis presented in the 

Preliminary Economic Analysis (see 

Section VIII above), OSHA concludes 

that the proposal would impose a 

Federal mandate on the private sector in 

excess of $100 million in expenditures 

in any one year. The Preliminary 

Economic Analysis constitutes the 

written statement containing a 

qualitative and quantitative assessment 

of the anticipated costs and benefits 

required under Section 202(a) of the 

UMRA (2 U.S.C. 1532). 

XIII. Protecting Children From 

Environmental Health and Safety Risks 

Executive Order 13045 requires that 

Federal agencies submitting covered 

regulatory actions to OMB’s Office of 

Information and Regulatory Affairs 

(OIRA) for review pursuant to Executive 

Order 12866 must provide OIRA with 

(1) an evaluation of the environmental 

health or safety effects that the planned 

regulation may have on children, and 

(2) an explanation of why the planned 

regulation is preferable to other 

potentially effective and reasonably 

feasible alternatives considered by the 

agency. Executive Order 13045 defines 

‘‘covered regulatory actions’’ as rules 

that may (1) be economically significant 

under Executive Order 12866 (i.e., a 

rulemaking that has an annual effect on 

the economy of $100 million or more, or 

would adversely effect in a material way 

the economy, a sector of the economy, 

productivity, competition, jobs, the 

environment, public health or safety, or 

State, local, or tribal governments or 

communities), and (2) concern an 

environmental health risk or safety risk 

that an agency has reason to believe may 

disproportionately affect children. In 

this context, the term ‘‘environmental 

health risks and safety risks’’ means 

risks to health or safety that are 

attributable to products or substances 

that children are likely to come in 

contact with or ingest (e.g., through air, 

food, water, soil, product use). 

The proposed respirable crystalline 

silica rule is economically significant 

under Executive Order 12866 (see 

Section VIII of this preamble). However, 

after reviewing the proposed respirable 

crystalline silica rule, OSHA has 

determined that the rule would not 

impose environmental health or safety 

risks to children as set forth in 

Executive Order 13045. The proposed 

rule would require employers to limit 

employee exposure to respirable 

crystalline silica and take other 

precautions to protect employees from 

adverse health effects associated with 

exposure to respirable crystalline silica. 

OSHA is not aware of any studies 

showing that exposure to respirable 

crystalline silica disproportionately 

affects children or that employees under 

18 years of age who may be exposed to 

respirable crystalline silica are 

disproportionately affected by such 

exposure. Based on this preliminary 

determination, OSHA believes that the 

proposed respirable crystalline silica 

rule does not constitute a covered 

regulatory action as defined by 

Executive Order 13045. However, if 

such conditions exist, children who are 

exposed to respirable crystalline silica 

in the workplace would be better 

protected from exposure to respirable 

crystalline silica under the proposed 

rule than they are currently. 

XIV. Environmental Impacts 

OSHA has reviewed the silica 

proposal according to the National 

Environmental Policy Act (NEPA) of 

1969 (42 U.S.C. 4321 et seq.), the 

regulations of the Council on 

Environmental Quality (40 CFR part 

1500), and the Department of Labor’s 

NEPA procedures (29 CFR part 11). 

Based on that review, OSHA does not 

expect that the proposed rule, in and of 

itself, would create additional 

environmental issues. However, as 

noted in the SBREFA report (OSHA, 

2003, p. 77), some Small Entity 

Representatives (SERs) raised the 

possibility that the use of wet methods 

to limit occupational (and 

environmental) exposures in some areas 

may violate EPA rules with respect to 

suspended solids in runoff unless 

provision is made for recycling or 

settling the suspended solids out of the 

water. The SBREFA Panel 

recommended that OSHA investigate 

this issue, add appropriate costs if 

necessary, and solicit comment on this 

issue. 

Some large construction projects may 

already require a permit to address 

storm water runoff, independent of any 

OSHA requirements to limit worker 

exposure to silica. These environmental 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56440 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

requirements come from or reference the 

Clean Water Act of 1987. As applied to 

construction activities, EPA 

requirements generally pertain to 

projects of one acre or more and impose 

the use of Best Management Practices 

(BMPs) to minimize the pollution, via 

water runoff, of storm water collection 

systems and surface waters. In some 

cases, these requirements are 

administered by States. 

Otherwise, the use of wet methods to 

control silica dust as mandated by an 

OSHA silica standard is not directly 

addressed by EPA requirements. Local 

governments, however, might require 

compliance with EPA BMPs when 

granting construction permits. As an 

example, the California Department of 

Transportation’s Construction Site Best 

Management Practice (BMP) Field 

Manual and Troubleshooting Guide 

includes the following guidance for 

paving and grinding operations: ‘‘Do not 

allow wastes, such as AC [asphalt 

concrete] pieces, PCC [Portland concrete 

cement] grinding residue/slurry, sand/

gravel, exposed aggregate concrete 

residue, or dig-out materials into storm 

drains or receiving waters. Sweep, 

vacuum, and collect such wastes and 

recycle or dispose of properly’’ (State of 

California, Department of 

Transportation, 2003). Contractors 

following these BMPs would need to 

take steps to prevent water used for dust 

control from running into storm drains, 

drainage ditches, or surface waters. 

Slurries left on paved areas would need 

to be swept or vacuumed to prevent 

subsequent runoff during storms. 

It should be noted that the objective 

of these BMPs is a reduction in the 

amount of pollutants washed into storm 

drain systems or surface waters, rather 

than reductions in discharges per se. 

The environmental concern is that the 

use of wet methods to control silica dust 

would, besides creating silica slurry, 

facilitate discharges of other pollutants. 

The silica controls costed by OSHA in 

Chapter VI of the Preliminary Economic 

Analysis show six tasks where wet 

methods are suggested: stationary 

masonry saws, hand-held masonry 

saws, walk-behind and other large 

concrete saws, concrete grinding with 

walk-behind equipment, asphalt 

milling, and pavement breaking and 

other demolition with jackhammers. A 

detailed review of the control measures 

for these equipment types suggests that 

only the use of wet methods with 

pavement breakers has the potential to 

directly result in runoff discharges to 

storm drains or surface waters. Even 

then, the water required would most 

often not create a runoff potential. The 

control costs for each of these jobs 

contains a productivity impact factor, 

part of which is intended to account for 

extra cleanup time associated with use 

of wet methods to control dust, 

including sweeping or vacuuming of 

silica slurry. However, such efforts may 

be less laborious than having to clean 

up free silica dust and may result in a 

net decrease in silica (and any other 

contaminants related to its production) 

running off into the water supply. 

OSHA’s estimate of the potential 

environmental impact of each of these 

six equipment types is summarized 

below: 

• Stationary masonry saws: Most 

stationary saws come equipped with a 

water basin that typically holds several 

gallons of water and a pump for 

recycling water for wet cutting. The 

water is recirculated and, thus, not 

continually discharged. When emptied, 

the amount of water is not sufficient to 

produce a runoff. 

• Hand-held masonry saws: Large 

quantities of water typically are not 

required. Water is supplied from a small 

capacity water tank. Any slurry residue 

after cutting could be dealt with by 

sweeping or vacuuming. 

• Walk-behind and other large 

concrete saws: Larger concrete saws are 

equipped with a tank to supply water to 

the blade while cutting. These saws 

leave a slurry residue, but do not require 

so much water as to create a runoff. 

• Walk-behind concrete grinders and 

millers: Some tools are equipped with a 

water-feed system. In these, a water line 

from a tank, a garden hose, or other 

water supply leads to the grinding head 

and delivers water to spray or flood the 

cutting tool and/or the work surface. 

When an automatic water feed is not 

available, a helper can apply water 

directly to the cutting surface. While 

such wet methods might generate 

enough water to create a runoff, these 

grinding and milling activities are 

typically done during the finishing 

stages of structure construction (e.g., 

parking garages) and often inside the 

structure. Thus, direct discharges to 

storm drains or surface waters are 

unlikely. 

• Asphalt milling for pavement 

resurfacing: A typical asphalt milling 

machine has a built-in reservoir from 

which water is applied to the cutting 

drum. The amount of water used, 

however, is insufficient to produce a 

runoff. 

• Impact drillers/pavement breakers: 

Water for dust suppression can be 

applied manually, or using a semiautomated water-feed device. In the 

simplest method for suppressing dust, a 

dedicated helper directs a constant 

spray of mist at the impact point while 

another worker operates the 

jackhammer. The helper can use a hose 

with a garden-style spray nozzle to 

maintain a steady and carefully directed 

mist at the impact point where material 

is broken and crushed. Jackhammers 

retrofitted with a focused water mist 

aimed at the tip of the blade offer a 

dramatic decrease in silica exposure. 

Although water-fed jackhammers are 

not commercially available, it is neither 

expensive nor difficult to retrofit 

equipment. Studies suggest that a water 

flow rate of 1⁄8 to 1⁄4 gallon per minute 

is best for silica dust control. At this 

rate, about 7.5 to 15 gallons of water per 

hour would be applied to (i.e., sprayed 

on) the work area. It is unclear whether 

this quantity of water applied to a 

moveable work area at a constant rate 

would produce a runoff. If the work 

were in sufficient proximity to a storm 

drain or surface water, the contractor 

might need to use a simple barrier to 

prevent the water from entering the 

drain, or filter it. Because the volume of 

water is relatively small, the costs for 

such barriers are likely insubstantial. 

However, because this type of runoff 

could happen occasionally, OSHA has 

added costs for barriers in costing silica 

controls for this task. 

As a result of this review, OSHA has 

made a determination that the silica 

proposal would have little potential 

impact on air, water, or soil quality; 

plant or animal life; the use of land; or 

aspects of the external environment. As 

described above in this section, effective 

abatement measures are available where 

the potential for environmental impacts 

exist. Therefore, OSHA preliminarily 

concludes that the proposed standard 

would have no significant 

environmental impacts. However, while 

the Agency does not believe that the 

proposed rule would create significant 

costs, or otherwise pose a significant 

challenge, for employers to comply with 

existing environmental rules, OSHA 

welcomes comment on this or any other 

environmentally related issues, or 

potential conflicts with other agency 

rules. 

XV. Public Participation 

OSHA encourages members of the 

public to participate in this rulemaking 

by submitting comments on the 

proposal and by providing oral 

testimony and documentary evidence at 

the informal public hearings that the 

Agency will convene after the comment 

period ends. The Agency invites 

interested persons having knowledge of, 

or experience with, occupational 

exposure to silica and the issues raised 

by the proposed rule to participate in 

this process, and welcomes any 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56441 

pertinent data and information that will 

provide it with the best available 

evidence on which to develop the final 

regulatory requirements. 

The Agency has scheduled time 

during the informal rulemaking hearing 

in Washington, DC, for participants to 

testify on the Health Effects Literature 

Review and Preliminary Quantitative 

Risk Assessment in the presence of peer 

reviewers. Peer reviewers will 

subsequently be able to submit amended 

final comments to the record. As 

described in OSHA’s peer review 

agenda, peer reviewers have reviewed 

OSHA’s draft Health Effects Literature 

Review and Preliminary Quantitative 

Risk Assessment and have submitted 

written reports that the Agency has 

considered prior to publication of the 

proposed rule. The open comment 

period and informal hearing will 

provide the public an opportunity to 

submit information to the record that it 

believes will benefit the peer review, 

and to testify in the presence of the 

reviewers. This section describes the 

procedures the public must use to 

submit their comments to the docket in 

a timely manner, and to schedule an 

opportunity to deliver oral testimony 

and provide documentary evidence at 

informal public hearings on the 

proposal. Comments, notices of 

intention to appear, hearing testimony 

and documentary evidence will be 

available for inspection and copying at 

the OSHA Docket Office. You also 

should read the sections above titled 

DATES and ADDRESSES for additional 

information on submitting comments, 

documents, the presence of peer 

reviewers at the hearings, and requests 

to the Agency for consideration in this 

rulemaking. 

Written Comments. OSHA invites 

interested persons to submit written 

data, views, and arguments concerning 

this proposal. In particular, OSHA 

encourages interested persons to 

comment on the issues raised in Section 

I of this preamble. When submitting 

comments, persons must follow the 

procedures specified above in the 

sections titled DATES and ADDRESSES. 

The comments must clearly identify the 

provision of the proposal you are 

addressing, the position taken with 

respect to each issue, and the basis for 

that position. Comments, along with 

supporting data and references, received 

by the end of the specified comment 

period will become part of the record 

and will be available for public 

inspection and copying at the OSHA 

Docket Office as well as online at 

www.regulations.gov (Docket Number 

OSHA–2010–0034). 

Informal Public Hearings. Pursuant to 

section 6(b)(3) of the Act, members of 

the public will have an opportunity to 

provide oral testimony concerning the 

issues raised in this proposal at informal 

public hearings. The legislative history 

of section 6 of the OSH Act, as well as 

OSHA’s regulation governing public 

hearings (29 CFR 1911.15), establish the 

purpose and procedures of informal 

public hearings. Although the presiding 

officer of the hearing is an 

administrative law judge (ALJ) and 

questioning of witnesses is allowed on 

crucial issues, the proceeding is largely 

informal and essentially legislative in 

purpose. Therefore, the hearing 

provides interested persons with an 

opportunity to make oral presentations 

in the absence of procedural restraints 

or rigid procedures that could impede or 

protract the rulemaking process. The 

hearing is not an adjudicative 

proceeding subject to the technical rules 

of evidence. Instead, it is an informal 

administrative proceeding convened for 

the purpose of gathering and clarifying 

information. The regulations that govern 

the hearings and the prehearing 

guidelines issued for the hearing will 

ensure that participants are treated 

fairly and provided due process. This 

approach will facilitate the development 

of a clear, accurate, and complete 

record. Accordingly, application of 

these rules and guidelines will be such 

that questions of relevance, procedure, 

and participation generally will be 

resolved in favor of developing a clear, 

accurate, and complete record. Conduct 

of the hearing will conform to 29 CFR 

1911.15. In addition, the Assistant 

Secretary may, on reasonable notice, 

issue additional or alternative 

procedures to expedite the proceedings, 

to provide greater procedural 

protections to interested persons or to 

further any other good cause consistent 

with applicable law (29 CFR 1911.4). 

Although the ALJ presiding over the 

hearing makes no decision or 

recommendation on the merits of the 

proposal, the ALJ has the responsibility 

and authority necessary to ensure the 

hearing progresses at a reasonable pace 

and in an orderly manner. To ensure 

that interested persons receive a full and 

fair hearing, the ALJ has the power to 

regulate the course of the proceedings; 

dispose of procedural requests, 

objections, and comparable matters; 

confine presentations to matters 

pertinent to the issues the proposed rule 

raises; use appropriate means to regulate 

the conduct of persons present at the 

hearing; question witnesses and permit 

others to do so; limit the time for such 

questioning; and leave the record open 

for a reasonable time after the hearing 

for the submission of additional data, 

evidence, comments and arguments (29 

CFR 1911.16). 

At the close of the hearing the ALJ 

will establish a post-hearing comment 

period for interested persons who filed 

a timely notice of intention to appear at 

the hearing. During the first part of the 

post-hearing period, those persons may 

submit additional data and information 

to OSHA. During the second part they 

may submit final briefs, arguments, and 

summations. 

Notice of Intention to Appear to 

Provide Testimony at the Informal 

Public Hearing. Interested persons who 

intend to provide oral testimony at the 

informal public hearing must file a 

notice of intention to appear by using 

the procedures specified above in the 

sections titled DATES and ADDRESSES. 

This notice must provide the following 

information: 

Name, address, email address, and 

telephone number of each individual 

who will give oral testimony; 

Name of the establishment or 

organization each individual represents, 

if any; 

Occupational title and position of 

each individual testifying; 

Approximate amount of time required 

for each individual’s testimony; 

If the individual requests to present 

testimony related to the Health Effects 

Literature Review and Preliminary 

Quantitative Risk Assessment, the 

notice should specify if the submitter 

requests this testimony be provided in 

the presence of peer reviewers; 

A brief statement of the position each 

individual will take with respect to the 

issues raised by the proposed rule; and 

A brief summary of documentary 

evidence each individual intends to 

present. 

Participants who need projectors and 

other special equipment for their 

testimony must contact Frank Meilinger 

at OSHA’s Office of Communications, 

telephone (202) 693–1999, no later than 

one week before the hearing begins. 

OSHA emphasizes that the hearings 

are open to the public; however, only 

individuals who file a notice of 

intention to appear may question 

witnesses and participate fully at the 

hearing. If time permits, and at the 

discretion of the ALJ, an individual who 

did not file a notice of intention to 

appear may be allowed to testify at the 

hearing, but for no more than 10 

minutes. 

Hearing testimony and documentary 

evidence. Individuals who request more 

than 10 minutes to present their oral 

testimony at the hearing or who will 

submit documentary evidence at the 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56442 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

hearing must submit (transmit, send, 

postmark, deliver) the full text of their 

testimony and all documentary 

evidence no later than December 11, 

2013. 

The Agency will review each 

submission and determine if the 

information it contains warrants the 

amount of time the individual requested 

for the presentation. If OSHA believes 

the requested time is excessive, the 

Agency will allocate an appropriate 

amount of time for the presentation. The 

Agency also may limit to 10 minutes the 

presentation of any participant who fails 

to comply substantially with these 

procedural requirements, and may 

request that the participant return for 

questioning at a later time. Before the 

hearing, OSHA will notify participants 

of the time the Agency will allow for 

their presentation and, if less than 

requested, the reasons for its decision. 

In addition, before the hearing OSHA 

will provide the pre-hearing guidelines 

and hearing schedule to each 

participant. 

Certification of the hearing record and 

Agency final determination. Following 

the close of the hearing and the posthearing comment periods, the ALJ will 

certify the record to the Assistant 

Secretary of Labor for Occupational 

Safety and Health. The record will 

consist of all of the written comments, 

oral testimony and documentary 

evidence received during the 

proceeding. The ALJ, however, will not 

make or recommend any decisions as to 

the content of the final standard. 

Following certification of the record, 

OSHA will review all the evidence 

received into the record and will issue 

the final rule based on the record as a 

whole. 

XVI. Summary and Explanation of the 

Standards 

(a) Scope and application 

OSHA is proposing to issue one 

standard addressing respirable 

crystalline silica exposure in general 

industry and maritime and a separate 

standard addressing exposure in the 

construction industry. The scope 

provisions are contained in paragraph 

(a) of the proposed standards. The 

proposed standard for the construction 

industry is similar to the proposed 

standard for general industry and 

maritime, and the standards are 

intended to provide equivalent 

protection for all workers while 

accounting for the different work 

activities, anticipated exposures, and 

other conditions in these sectors. The 

limited differences between the 

proposed construction and general 

industry/maritime standards exist 

because OSHA believes, based on the 

record developed to date, that certain 

activities in construction are different 

enough to warrant modified 

requirements. 

The proposed standards do not cover 

the agricultural sector, due to limited 

data on exposures and control measures 

in this sector. OSHA’s authority is also 

restricted in this area; since 1976, an 

annual rider in the Agency’s 

Congressional appropriations bill has 

limited OSHA’s use of funds with 

respect to farming operations that 

employ fewer than ten workers. 

Consolidated Appropriations Act, 1976, 

Public Law 94–439, 90 Stat. 1420, 1421 

(1976) (and subsequent appropriations 

acts). However, some evidence indicates 

that certain agricultural operations may 

result in exposures to respirable silica in 

excess of the proposed PEL. A literature 

review conducted by Swanepoel et al. 

(2010) identified studies that examined 

respirable quartz exposure and 

associated diseases in agricultural 

settings. Three of the exposure studies 

measured respirable quartz in the 

personal breathing zone of workers 

(Popendorf et al. 1982; Archer et al. 

2002; Lee et al. 2004). Popendorf et al. 

(1982) investigated exposures among 

citrus, peach, and grape harvesters; 

Archer et al. (2002) reported on 

farmworkers in eastern North Carolina; 

and Lee et al. (2004) examined citrus 

and grape harvesters in California. Each 

of these studies identified instances 

where exposures exceeded the proposed 

PEL. In particular, Archer et al. (2002) 

reported respirable quartz 

concentrations as high as 3910 mg/m3

among farmworkers during sweet potato 

transplanting. Area samples reported in 

two other studies support the belief that 

agricultural operations can generate 

high levels of respirable quartz. 

Gustafsson et al. (1978) reported average 

respirable quartz concentrations of 2000 

mg/m3 in open tractor cabs, while 

Lawson et al. (1995) reported respirable 

quartz concentrations ranging from 20– 

90 mg/m3 during rice farming 

operations. Little evidence was reported 

in the literature regarding diseases 

associated with respirable crystalline 

silica exposure in agricultural workers 

(Swanepoel et al., 2010). OSHA is 

interested in additional evidence 

relating to exposures to respirable 

crystalline silica that occur in 

agriculture and to associated control 

measures, as well as information related 

to the development of respirable 

crystalline silica-related diseases among 

workers in the agricultural sector, and is 

requesting such information in the 

‘‘Issues’’ section (Section I) of this 

preamble. 

In paragraph (b) (definition of 

‘‘respirable crystalline silica’’), OSHA 

proposes to cover quartz, cristobalite, 

and tridymite under the standard. The 

Agency believes the evidence supports 

this approach. OSHA currently has 

different permissible exposure limits 

(PELs) for different forms of crystalline 

silica. The current general industry 

PELs for cristobalite and tridymite are 

one half of the general industry PEL for 

quartz. This difference was based on the 

fact that early animal studies appeared 

to suggest that cristobalite and tridymite 

were more toxic to the lung than quartz. 

However, as discussed in OSHA’s 

Review of Health Effects Literature and 

summarized in Section V of this 

preamble, reviews of more recent 

studies have led OSHA to preliminarily 

conclude that cristobalite and tridymite 

are comparable to quartz in their 

toxicities. Also, a difference in toxicity 

between cristobalite and quartz has not 

been observed in epidemiologic studies. 

Exposure to tridymite has not been the 

subject of epidemiologic study. 

OSHA’s preliminary conclusion that 

quartz, cristobalite, and tridymite 

should be addressed under a single 

standard and subject to the same PEL is 

consistent with the recommendation of 

the National Institute for Occupational 

Safety and Health (NIOSH), which has 

a single Recommended Exposure Limit 

(REL) covering all forms of respirable 

crystalline silica. In addition, the 

American Conference of Governmental 

Industrial Hygienists (ACGIH) has 

issued a single Threshold Limit Value 

(TLV) for quartz and cristobalite. 

In 2003, OSHA presented respirable 

crystalline silica draft standards for both 

general industry and construction to the 

Small Business Regulatory Enforcement 

Fairness Act (SBREFA) review panel. 

The general industry scope has 

remained unchanged, while the 

SBREFA construction draft standard 

included two alternative scope 

provisions. The first option, which is 

included in the proposal, stated that the 

rule applied to all construction 

operations covered by 29 CFR part 1926. 

The second option was more restrictive, 

indicating the rule would apply only to 

abrasive blasting and other specified 

operations (cutting, sanding, drilling, 

crushing, grinding, milling, sawing, 

scabbling, scrapping, mixing, jack 

hammering, excavating, or disturbing 

materials that contain crystalline silica). 

The SBREFA panel recommended that 

OSHA continue to evaluate and 

consider modifications to the second 

option that could serve to limit the 

scope of the standard. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56443 

OSHA is proposing to cover all 

occupational exposures to respirable 

crystalline silica in construction work, 

as defined in 29 CFR 1910.12(b) and 

covered under 29 CFR part 1926, 

because the Agency wants to ensure that 

all activities are covered by the standard 

if they involve exposures that present a 

significant risk to workers. The second 

scope option in the SBREFA draft 

included activities that are typically 

associated with higher worker 

exposures to crystalline silica, but 

would not cover all operations that 

present a significant risk. 

Collectively, the proposed standards 

apply to occupational exposure in 

which respirable crystalline silica is 

present in an occupationally related 

context. Exposure of employees to the 

ambient environment, which may 

contain small concentrations of 

respirable crystalline silica unrelated to 

occupational activities, is not subject to 

the proposed standards. 

(b) Definitions 

‘‘Action level’’ is defined as an 

airborne concentration of respirable 

crystalline silica of 25 micrograms per 

cubic meter of air (25 mg/m3) calculated 

as an eight-hour time-weighted average 

(TWA). The action level triggers 

requirements for periodic exposure 

monitoring. In this proposal, as in other 

standards, the action level has been set 

at one-half of the PEL. 

Because of the variable nature of 

employee exposures to airborne 

concentrations of respirable crystalline 

silica, maintaining exposures below the 

action level provides reasonable 

assurance that employees will not be 

exposed to respirable crystalline silica 

at levels above the PEL on days when 

no exposure measurements are made. 

Even when all measurements on a given 

day fall below the PEL but are above the 

action level, there is a reasonable 

chance that on another day, when 

exposures are not measured, the 

employee’s actual exposure may exceed 

the PEL. Previous standards have 

recognized a statistical basis for using 

an action level of one-half the PEL (e.g., 

acrylonitrile, 29 CFR 1910.1045; 

ethylene oxide, 29 CFR 1910.1047). In 

brief, OSHA previously determined 

(based in part on research conducted by 

Leidel et al.) that where exposure 

measurements are above one-half the 

PEL, the employer cannot be reasonably 

confident that the employee is not 

exposed above the PEL on days when no 

measurements are taken (Leidel, et al., 

1975). Therefore, requiring periodic 

exposure measurements when the 

action level is exceeded provides 

employers with additional assurance 

that employees are being protected from 

exposures above the PEL. 

As exposures are lowered, the risk of 

adverse health effects among workers 

decreases. In addition, there is an 

economic benefit to employers who 

reduce exposure levels below the action 

level: They can avoid the costs 

associated with periodic exposure 

monitoring requirements. Some 

employers will be able to reduce 

exposures below the action level in all 

work areas, and other employers in 

some work areas. 

OSHA’s preliminary risk assessment 

indicates that significant risk remains at 

the proposed PEL of 50 mg/m3. At least 

one court has held that OSHA has a 

duty to impose additional requirements 

on employers to eliminate remaining 

significant risk when those 

requirements will afford benefits to 

workers and are feasible. Building and 

Construction Trades Department, AFL– 

CIO v. Brock, 838 F.2d 1258, 1269 (D.C. 

Cir 1988). OSHA’s preliminary 

conclusion is that the action level will 

result in a very real and necessary 

further reduction in risk beyond that 

provided by the PEL alone. OSHA’s 

decision to propose an action level of 

one-half of the PEL is based, in part, on 

the Agency’s successful experience with 

other standards, including those for 

inorganic arsenic (29 CFR 1910.1018), 

ethylene oxide (29 CFR 1910.1047), 

benzene (29 CFR 1910.1028), and 

methylene chloride (29 CFR 1910.1052). 

‘‘Competent person’’ means one who 

is capable of identifying existing and 

predictable respirable crystalline silica 

hazards in the surroundings or working 

conditions and who has authorization to 

take prompt corrective measures to 

eliminate them. The competent person 

concept has been broadly used in OSHA 

construction standards, particularly in 

safety standards. In OSHA shipyard 

standards, a defined role for the 

competent person focuses on confined 

space hazards, hot work, and explosive 

environments. Competent person 

requirements also apply to powder 

actuated tools. It is not the intent of this 

proposal to modify the existing 

competent person requirements in 

shipyard standards. 

As explained below in section (e) 

(Regulated areas and access control), 

employers have the option to develop a 

written access control plan in lieu of 

establishing regulated areas to minimize 

exposures to employees not directly 

involved in operations that generate 

respirable crystalline silica in excess of 

the PEL. The access control plan would 

require that a competent person identify 

areas where respirable crystalline silica 

exposures are, or can reasonably be 

expected to be, in excess of the PEL. 

The proposed standard does not 

specify particular training requirements 

for competent persons. Rather, the 

requirement for a competent person is 

performance-based; the competent 

person must be capable of effectively 

performing the duties assigned under 

the standard. Therefore, the competent 

person must have the knowledge and 

experience necessary to identify in 

advance tasks or operations during 

which exposures are reasonably 

expected to exceed the PEL, so that 

affected employees can be notified of 

the presence and location of areas where 

such exposures may occur, and the 

employer can take steps to limit access 

to these areas and provide appropriate 

respiratory protection. 

OSHA included more extensive 

competent person requirements in both 

the draft general industry/maritime and 

construction standards presented for 

review to the Small Business Regulatory 

Enforcement Fairness Act (SBREFA) 

review panel. The SBREFA draft 

standards included requirements for a 

competent person at each worksite to 

ensure compliance with the provisions 

of the standard. Specifically, the 

SBREFA draft standards required that 

the competent person: Evaluate 

workplace exposures and the 

effectiveness of controls, and implement 

corrective measures to ensure that 

employees are not exposed in excess of 

the PEL; establish regulated areas 

wherever the airborne concentration of 

respirable crystalline silica exceeds or 

can reasonably be expected to exceed 

the PEL, taking into consideration 

factors that could affect exposures such 

as wind direction, changes in work 

processes, and proximity to other 

workplace operations; and check the 

regulated area daily to ensure the 

boundary is maintained. The SBREFA 

draft standards also required the 

employer to ensure that the competent 

person inspect abrasive blasting 

activities as necessary to ensure that 

controls are being properly used and 

remain effective; participate in the 

evaluation of alternative blast media; 

and communicate with other employers 

to inform them of the boundaries of 

regulated areas established around 

abrasive blasting operations. 

Many small entity representatives 

(SERs) from the construction industry 

who reviewed the SBREFA draft 

standard found the requirements for a 

competent person hard to understand 

(OSHA, 2003). Many believed that the 

competent person required a high skill 

level, while others thought that a large 

proportion of their employees would 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56444 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

need to be trained. SERs thought that 

the requirements would be difficult to 

comply with and costly. These concerns 

may have been due to the specific 

regulatory language used in the SBREFA 

draft, rather than the general concept of 

competent person requirements. 

OSHA’s Advisory Committee on 

Construction Safety and Health 

recommended that the Agency retain 

the requirement and responsibilities for 

a competent person in the proposed rule 

(ACCSH, 2009). The Building and 

Construction Trades Department, AFL– 

CIO has also consistently recommended 

including competent person 

requirements in a proposed silica 

standard. 

OSHA has proposed limited 

competent person requirements because 

the Agency has preliminarily concluded 

that the provisions of the proposed 

standard will generally be effective 

without the involvement of an 

individual specifically designated as a 

competent person. For example, the 

proposed standard requires that the 

employer use engineering and work 

practice controls to reduce and maintain 

employee exposure to respirable 

crystalline silica to or below the PEL. 

OSHA believes that this provision 

adequately communicates this 

requirement to employers, and that an 

additional requirement for a ‘‘competent 

person’’ to evaluate the effectiveness of 

these controls and implement corrective 

measures in this standard is not 

necessary. However, the Agency is 

aware that competent person 

requirements have been included in 

other health and safety standards, and 

that some parties believe such 

requirements would be useful in the 

silica standard. OSHA is interested in 

information and comment on the 

appropriate role of a competent person 

in the respirable crystalline silica 

standard, and has included this topic in 

the ‘‘Issues’’ section (Section I) of this 

preamble. 

‘‘Employee exposure’’ means 

exposure to airborne respirable 

crystalline silica that would occur if the 

employee were not using a respirator. 

This definition is included to clarify the 

requirement that employee exposure be 

measured as if no respiratory protection 

were being worn. It is consistent with 

OSHA’s previous use of the term in 

other standards. 

‘‘Objective data’’ means information, 

such as air monitoring data from 

industry-wide surveys or calculations 

based on the composition or chemical 

and physical properties of a substance, 

demonstrating employee exposure to 

respirable crystalline silica associated 

with a particular product, material, 

process, operation, or activity. The data 

must reflect workplace conditions 

closely resembling the processes, types 

of material, control methods, work 

practices, and environmental conditions 

in the employer’s current operations. 

Objective data is further discussed 

below in section (d) (Exposure 

Assessment). 

‘‘Physician or other licensed health 

care professional (PLHCP)’’ means an 

individual whose legally permitted 

scope of practice (i.e., license, 

registration, or certification) allows him 

or her to independently provide or be 

delegated the responsibility to provide 

some or all of the particular health care 

services required by paragraph (h) of 

this section. This definition is included 

because the proposed standard requires 

that all medical examinations and 

procedures be performed by or under 

the supervision of a PLHCP. 

Any PLHCP may perform the medical 

examinations and procedures required 

under the standard when they are 

licensed, registered, or certified by state 

law to do so. The Agency recognizes 

that this means that the personnel 

qualified to provide the required 

medical examinations and procedures 

may vary from state to state, depending 

on state licensing or certification laws. 

This provision of the proposed rule 

grants the employer the flexibility to 

retain the services of a variety of 

qualified licensed health care 

professionals, provided that these 

individuals are licensed to perform, or 

be delegated the responsibility to 

perform, the specified service. OSHA 

believes that this flexibility will reduce 

cost and compliance burdens for 

employers and increase convenience for 

employees. The approach taken in this 

proposed standard is consistent with the 

approach OSHA has taken in other 

recent standards, such as chromium (VI) 

(29 CFR 1910.1026), bloodborne 

pathogens (29 CFR 1910.1030), and 

respiratory protection (29 CFR 

1910.134). 

‘‘Regulated area’’ means an area, 

demarcated by the employer, where an 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica exceeds, or can reasonably be 

expected to exceed, the PEL. This 

definition is consistent with the use of 

the term in other standards, including 

those for chromium (VI) (29 CFR 

1910.1026), 1,3-butadiene (29 CFR 

1910.1051), and methylene chloride (29 

CFR 1910.1052). 

‘‘Respirable crystalline silica’’ means 

airborne particles that contain quartz, 

cristobalite, and/or tridymite and whose 

measurement is determined by a 

sampling device designed to meet the 

characteristics for respirable-particlesize-selective samplers specified in the 

International Organization for 

Standardization (ISO) 7708:1995: Air 

Quality—Particle Size Fraction 

Definitions for Health-Related 

Sampling. 

The Agency’s proposed definition for 

respirable crystalline silica seeks to 

harmonize the Agency’s practice with 

current aerosol science and the ISO 

definition of respirable particulate mass. 

Thus, the proposed definition would 

encompass the polymorphs of silica 

covered under current OSHA standards 

and would be consistent with the 

international consensus that the ISO 

definition of respirable particulate mass 

represents. The American Conference of 

Governmental Industrial Hygienists 

(ACGIH) and the European Committee 

for Standardization (CEN) have adopted 

the ISO definition of respirable 

particulate mass. The National Institute 

for Occupational Safety and Health 

(NIOSH) has also adopted the ISO 

definition of respirable particulate mass 

in its Manual of Sampling and 

Analytical Methods. Adoption of this 

definition by OSHA would allow for 

workplace sampling for respirable 

crystalline silica exposures to be 

conducted using any particulate 

sampling device that conforms to the 

ISO definition (i.e., that collects dust 

according to the particle collection 

efficiency curve specified in the ISO 

standard). OSHA’s current respirable 

crystalline silica PELs are measured 

according to a particle collection 

efficiency curve formerly specified by 

ACGIH, which is now obsolete. The 

relationship between the ISO definition 

of respirable particulate mass and the 

ACGIH criteria is discussed in greater 

detail in the Technological Feasibility 

chapter of the Preliminary Economic 

Analysis, and is summarized in section 

VIII of this preamble. 

The definitions for ‘‘Assistant 

Secretary,’’ ‘‘Director,’’ ‘‘High-efficiency 

particulate air [HEPA] filter,’’ and ‘‘This 

section’’ are consistent with OSHA’s 

previous use of these terms in other 

health standards. 

(c) Permissible Exposure Limit (PEL) 

In paragraph (c), OSHA proposes to 

set an 8-hour time-weighted average 

(TWA) exposure limit of 50 micrograms 

of respirable crystalline silica per cubic 

meter of air (50 mg/m3). This limit 

means that over the course of any 8- 

hour work shift, the average exposure to 

respirable crystalline silica cannot 

exceed 50 mg/m3. The proposed PEL is 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56445 

38OSHA regulates silica exposure in three 

maritime-related activities: Shipyards (29 CFR 

1915.1000, Table Z), Marine Terminals (29 CFR 

1917.1(a)(2)(xiii)), and Longshoring (29 CFR 

1918.1(b)(9)). Marine Terminals and Longshoring 

incorporate by reference the toxic and hazardous 

substance requirements in subpart Z of the general 

industry standard, which includes both a particlecounting formula and a mass formula for the silica 

PEL (29 CFR 1910.1000, Table Z–3). Shipyards has 

its own subpart Z, which uses the particle-counting 

formula for the silica PEL. Thus, under the current 

scheme, Marine Terminals and Longshoring use 

two alternative PEL formulas, while Shipyards uses 

a single PEL formula. The proposal eliminates this 

discrepancy by adopting a single PEL (50 mg/m3) for 

all three maritime sectors, in addition to 

construction and general industry. 

In this section, the Agency distinguishes between 

the proposed maritime PEL (50 mg/m3 for all three 

maritime sectors) and the current shipyard PEL (the 

particle-counting formula required for shipyards 

and construction). 

the same for both general industry/

maritime 38 and construction. 

OSHA currently expresses the general 

industry PEL for respirable crystalline 

silica in the form of quartz in two ways. 

The first, which is based on gravimetric 

measurement, is derived from the 

formula (PEL = (10 mg/m3)/(% quartz + 

2) as respirable dust). This is 

approximately equivalent to 100 mg/m3

of respirable crystalline silica. The 

current general industry PELs for the 

polymorphs cristobalite and tridymite 

are one-half of the value calculated from 

this formula, or approximately 50 mg/m3

of respirable crystalline silica. The 

proposed PEL is thus approximately 

equivalent to the current general 

industry PELs for cristobalite and 

tridymite. In cases where exposures to 

quartz, cristobalite, and/or tridymite 

occur at the same time, the PEL is 

calculated following the procedure 

specified in 29 CFR 1910.1000(d)(2) for 

exposures to mixtures of substances 

having an additive effect on the body or 

target organ system. 

The second way OSHA expresses the 

general industry PEL for respirable 

crystalline silica in the form of quartz is 

based on a now-obsolete particle count 

sampling method, and is presented in 

terms of millions of particles per cubic 

foot (mppcf). This PEL is based on the 

formula (PELmppcf = 250/(% quartz + 5) 

as respirable dust). The current general 

industry PELs for cristobalite and 

tridymite are one-half of the value 

calculated from this formula. These two 

parallel PELs in general industry were 

originally believed to be equivalent 

values (Ayer, 1995). However, as 

discussed below, the values are now 

considered to differ substantially. 

The current PEL for crystalline silica 

in the form of quartz in construction 

and shipyards (PELmppcf = 250/(% quartz 

+ 5) as respirable dust) is expressed only 

in terms of mppcf. This is the same 

formula as the parallel PEL for 

respirable crystalline silica in the form 

of quartz in general industry that is 

expressed in mppcf. The Mineral Dusts 

tables that contain the silica PELs for 

construction and shipyards do not 

clearly express PELs for cristobalite and 

tridymite. 29 CFR 1926.55; 29 CFR 

1915.1000. This lack of textual clarity 

likely results from a transcription error 

during the codification of these rules. 

OSHA’s current proposal provides the 

same PEL for quartz, cristobalite, and 

tridymite, in general industry, 

construction, and shipyards. 

The current PELs in general industry, 

construction, and shipyards are 8-hour 

TWA exposure limits. Both formulas 

express the PEL in terms of a 

permissible level of exposure to 

respirable dust, rather than a 

permissible level of exposure to 

respirable crystalline silica. The higher 

the percentage of crystalline silica in the 

sample, the lower the level of respirable 

dust allowed. 

The current PELs for construction and 

shipyards (and the parallel PEL 

presented for general industry) are 

based on a particle count method long 

rendered obsolete by gravimetric 

respirable mass sampling, which yields 

results reported in milligrams or 

micrograms per cubic meter of air (mg/ 

m3or mg/m3). Gravimetric sampling 

methods are the only methods currently 

available to OSHA compliance 

personnel. Since the current 

construction and shipyard PELs are 

expressed only in terms of mppcf, the 

results of the gravimetric sampling must 

be converted to an equivalent mppcf 

value. 

In order to determine a formula for 

converting from mg/m3 to mppcf, OSHA 

requested assistance from the National 

Institute for Occupational Safety and 

Health (NIOSH). Based on its review of 

published studies comparing the 

particle count and gravimetric methods, 

NIOSH recommended a conversion 

factor of 0.1 mg/m3 respirable dust to 1 

mppcf. OSHA has determined that this 

conversion factor should be applied to 

silica sampling results used to 

characterize exposures in construction 

and shipyard operations. Appendix E to 

CPL 03–00–007, OSHA’s National 

Emphasis Program for Crystalline Silica, 

illustrates how the conversion factor is 

applied to enforce the current PEL for 

crystalline silica in the construction and 

shipyard industries. Applying the 

conversion factor to a sample consisting 

of pure (i.e., 100%) crystalline silica 

indicates that the current PEL for 

construction and shipyards is 

approximately equivalent to 250 mg/m3

of respirable crystalline silica. 

OSHA’s current PELs for respirable 

crystalline silica are expressed as 

respirable dust, or respirable particulate 

mass. The proposed PEL is expressed as 

respirable crystalline silica, or the 

amount of crystalline silica that is 

present as respirable particulate mass. 

Respirable particulate mass refers to 

airborne particulate matter that is 

capable of entering the gas-exchange 

region of the lung, where crystalline 

silica particles cause pathological 

damage. Only very small particles 

(particles of about 10 mg/m or less) are 

able to penetrate into the gas-exchange 

region of the lung. As particle size 

decreases, the relative proportion of 

particles that is expected to reach the 

gas-exchange region of the lung 

increases. 

Under the proposed definition of 

respirable crystalline silica in paragraph 

(b), respirable crystalline silica means 

airborne particles that contain quartz, 

cristobalite, and tridymite and whose 

measurement is determined by a 

sampling device designed to meet the 

characteristics for particle-size-selective 

samplers specified in International 

Organization for Standardization (ISO) 

7708:1995: Air Quality—Particle Size 

Fraction Definitions for Health-Related 

Sampling. This definition of respirable 

particulate mass is intended to 

correspond with airborne particulate 

matter that is capable of entering the 

gas-exchange region of the lung. It 

provides a formula for determining the 

respirable fraction based on the 

aerodynamic diameter of the particles, 

and represents an international 

consensus that has been adopted by the 

American Conference of Governmental 

Industrial Hygienists (ACGIH) and the 

European Committee for 

Standardization (CEN). The ISO 

definition is also used by the National 

Institute for Occupational Safety and 

Health (NIOSH) in its Manual of 

Sampling and Analytical Methods. The 

ISO definition of respirable particulate 

mass is discussed in greater detail in the 

Technological Feasibility chapter of the 

Preliminary Economic Analysis. 

OSHA currently has a PEL for 

exposure to total quartz dust (PEL = (30 

mg/m3)/(% quartz + 2) as total dust) in 

general industry. As with the PEL for 

respirable dust, the PELs for cristobalite 

and tridymite are one-half of the value 

calculated from this formula. The 

Agency does not have a PEL for 

exposure to total quartz dust for 

construction or shipyards. OSHA 

proposes to delete the PELs for exposure 

to total crystalline silica dust, because 

the Review of Health Effects Literature 

and Preliminary Quantitative Risk 

Assessment clearly relates development 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56446 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

of crystalline silica-related disease to 

respirable, rather than total, dust 

exposure. This view is consistent with 

ACGIH, which no longer has a TLV for 

total crystalline silica dust. NIOSH does 

not have a Recommended Exposure 

Level for total crystalline silica 

exposure, and neither the National 

Toxicology Program nor the 

International Agency for Research on 

Cancer has linked exposure to total 

crystalline silica dust exposure to 

cancer, as they have with respirable 

crystalline silica exposure. 

OSHA proposes a new PEL of 50 mg/ 

m3 because the Agency has 

preliminarily determined that 

occupational exposure to respirable 

crystalline silica at the current PEL 

results in a significant risk of material 

health impairment among exposed 

workers, and that compliance with the 

proposed standard will substantially 

reduce that risk. OSHA’s Preliminary 

Quantitative Risk Assessment, 

summarized in Section VI of this 

preamble, indicates that a 45-year 

exposure to respirable crystalline silica 

at the current general industry PEL 

would lead to between 13 and 60 excess 

deaths from lung cancer, 9 deaths from 

silicosis, 83 deaths from all forms of 

non-malignant respiratory disease 

(including silicosis), and 39 deaths from 

renal disease per 1000 workers. 

Exposures at the current construction 

and shipyard PEL would result in even 

higher levels of risk. As discussed in 

Section VII of this preamble, these 

results clearly represent a risk of 

material impairment of health that is 

significant within the context of the 

‘‘Benzene’’ decision. Indus. Union 

Dep’t, AFL–CIO v. Am. Petroleum Inst., 

448 U.S. 607 (1980). OSHA believes that 

lowering the PEL to 50 mg/m3 would 

reduce the lifetime excess risk of death 

per 1000 workers to between 6 and 26 

deaths from lung cancer, 7 deaths from 

silicosis, 43 deaths from all forms of 

non-malignant respiratory disease 

(including silicosis), and 32 deaths from 

renal disease. 

OSHA considers the level of risk 

remaining at the proposed PEL to be 

significant. However, the proposed PEL 

is set at the lowest level that the Agency 

believes to be technologically feasible. 

As discussed in the Technological 

Feasibility chapter of the Preliminary 

Economic Analysis and summarized in 

section VIII of this preamble, OSHA’s 

analysis indicates that exposures at the 

proposed PEL can be measured with a 

reasonable degree of precision and 

accuracy. In addition, the analysis 

presented in the Technological 

Feasibility chapter of the Preliminary 

Economic Analysis makes clear that 

many industries and operations could 

not achieve an alternative PEL of 25 mg/ 

m3 with engineering and work practice 

controls alone. As guided by the 1988 

‘‘Asbestos’’ decision (Bldg & Constr. 

Trades Dep’t v. Brock, 838 F.2d 1258, 

1266 (DC Cir. 1988)), OSHA is 

proposing additional requirements to 

further reduce the remaining risk. 

OSHA anticipates that the ancillary 

provisions in the proposed standard, 

including requirements for regulated 

areas and medical surveillance, will 

further reduce the risk beyond the 

reduction that would be achieved by the 

proposed PEL alone. OSHA also 

believes that a new PEL, expressed as a 

gravimetric measurement of respirable 

crystalline silica, will improve 

compliance because the PEL is simple 

and relatively easy to understand. In 

comparison, the existing PELs require 

application of a formula to account for 

the crystalline silica content of the dust 

sampled and, in the case of the 

construction and shipyard PELs, a 

conversion of mppcf to mg/m3 as well. 

OSHA believes that it is appropriate 

to establish a single PEL that applies to 

respirable quartz, cristobalite, and 

tridymite. As explained in the Review of 

Health Effects Literature and 

Preliminary Quantitative Risk 

Assessment (see sections V and VI of 

this preamble for summaries), research 

indicates that certain physical factors 

may affect the toxicologic potency of 

crystalline silica. These factors include 

particle surface characteristics, the age 

of fractured surfaces of the crystal 

particle, the presence of impurities on 

particle surfaces, and coating of the 

particle. These factors may vary among 

different workplace settings, suggesting 

that the risk to workers exposed to a 

given level of respirable crystalline 

silica may not be equivalent in different 

work environments. The Agency’s 

Quantitative Risk Assessment, 

summarized in section VI of this 

preamble, relies on studies involving a 

range of work environments; from study 

to study, workers’ exposures to 

respirable crystalline silica varied in 

terms of particle age, surface impurities, 

and particle coatings. While the risk 

estimates that OSHA derived using data 

from different work environments are 

somewhat dissimilar, and these 

differences may be due in part to 

variations in particle toxicity, all of 

OSHA’s risk estimates indicate 

significant risk above the proposed PEL 

of 50 mg/m3. Thus, while the available 

evidence is not sufficient to establish 

precise quantitative differences in risk 

based on these physical factors, the 

Agency’s findings of significant risk are 

representative of a wide range of 

workplaces reflecting differences in the 

form of silica present, surface 

properties, and impurities. OSHA is 

therefore proposing a single PEL for 

respirable quartz, cristobalite, and 

tridymite. 

OSHA currently has separate entries 

in 29 CFR 1910.1000 Table Z–1 for 

cristobalite, quartz, tripoli (as quartz), 

and tridymite. The proposal would 

present a single entry for crystalline 

silica, as respirable dust, with a cross 

reference to the new standard. As 

discussed above, the proposed PEL 

applies to quartz, cristobalite, and 

tridymite. Tripoli, which is extremely 

fine-grained crystalline silica, is covered 

under the proposed PEL as quartz. 

Comparable revisions would be made to 

29 CFR 1915.1000 Table Z and 29 CFR 

1926.55 Appendix A. 

(d) Exposure Assessment 

Paragraph (d) of the proposed 

standard sets forth requirements for 

assessing employee exposures to 

respirable crystalline silica. The 

requirements are issued pursuant to 

section 6(b)(7) of the OSH Act, which 

mandates that any standard 

promulgated under section 6(b) shall, 

where appropriate, ‘‘provide for 

monitoring or measuring employee 

exposure at such locations and 

intervals, and in such manner as may be 

necessary for the protection of 

employees.’’ 29 U.S.C. 655(b)(7). 

As a general matter, monitoring of 

employee exposure to toxic substances 

is a well-recognized and accepted risk 

management tool. The purposes of 

requiring an assessment of employee 

exposures to respirable crystalline silica 

include: determination of the extent and 

degree of exposure at the worksite; 

identification and prevention of 

employee overexposure; identification 

of the sources of exposure; collection of 

exposure data so that the employer can 

select the proper control methods to be 

used; and evaluation of the effectiveness 

of those selected methods. Assessment 

enables employers to meet their legal 

obligation to ensure that their 

employees are not exposed in excess of 

the permissible exposure level and to 

ensure employees have access to 

accurate information about their 

exposure levels, as required by section 

8(c)(3) of the Act. 29 U.S.C. 657(c)(3). In 

addition, the availability of exposure 

data enables PLHCPs performing 

medical examinations to be informed of 

the extent of occupational exposures. 

Paragraph (d)(1) contains proposed 

general requirements for exposure 

assessment. The general requirements 

for assessing exposure to respirable 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56447 

crystalline silica in the proposed 

standard are similar to the requirements 

contained in previous OSHA substancespecific health standards. Except as 

provided for in the construction 

standard under paragraph (d)(8), 

paragraph (d)(1)(i) requires each 

employer to assess the exposure of any 

employees who are exposed, or may 

reasonably be expected to be exposed, to 

respirable crystalline silica at or above 

the action level. Under paragraph 

(d)(1)(ii), monitoring to determine 

employee exposures must represent the 

employee’s time-weighted average 

exposure to airborne respirable 

crystalline silica over an 8-hour 

workday. Samples must be taken within 

the employee’s breathing zone (i.e., 

‘‘personal breathing zone samples’’ or 

‘‘personal samples’’), and must 

represent the employee’s exposure 

without regard to the use of respiratory 

protection. 

Employers must accurately 

characterize the exposure of each 

employee to respirable crystalline silica. 

In some cases, this will entail 

monitoring all exposed employees. In 

other cases, as set out in proposed 

paragraph (d)(1)(iii), monitoring of 

‘‘representative’’ employees is 

sufficient. Representative exposure 

sampling is permitted when a number of 

employees perform essentially the same 

job on the same shift and under the 

same conditions. For employees 

engaged in similar work, it may be 

sufficient to monitor a fraction of these 

employees in order to obtain data that 

are ‘‘representative’’ of the remaining 

employees. Under the proposed 

standard, a representative sample must 

include employee(s) reasonably 

expected to have the highest exposures. 

For example, this may involve 

monitoring the exposure of the 

employee closest to an exposure source. 

This exposure result may then be 

attributed to the remaining employees 

in the group. 

Representative exposure monitoring 

must include at least one full-shift 

sample taken for each job function in 

each job classification, in each work 

area, for each shift. These samples must 

consist of either a single sample 

characteristic of the entire shift or 

consecutive samples taken over the 

length of the shift. In many cases, fullshift samples on two or more days may 

be necessary to adequately characterize 

exposure and obtain results that are 

representative of employees with the 

highest exposure for each job 

classification. Where employees are not 

performing the same job under the same 

conditions, representative sampling will 

not adequately characterize actual 

exposures, and individual monitoring is 

necessary. 

Paragraph (d)(2)(i) of the proposed 

standard requires employers to conduct 

an initial exposure assessment by 

performing initial monitoring of any 

employees who are exposed, or may 

reasonably be expected to be exposed, to 

respirable crystalline silica at or above 

the action level. Further obligations 

under the standard are based on the 

results of this initial assessment. These 

may include obligations for periodic 

monitoring, establishment of regulated 

areas, implementation of control 

measures, and provision of medical 

surveillance. 

The proposed standard, paragraph 

(d)(2)(ii), provides two exceptions to the 

requirement to conduct initial exposure 

monitoring. First, under paragraph 

(d)(2)(ii)(A), employers may rely on 

existing monitoring data to satisfy the 

requirement for an initial exposure 

assessment if employee exposures have 

been monitored within 12 months prior 

to the effective date of the standard 

under conditions that closely resemble 

those currently prevailing, and if that 

monitoring was conducted using one of 

the sampling and analytical methods 

specified in paragraph (d)(5)(i). This 

provision is intended to make it clear 

that employers who have recently 

performed appropriate employee 

monitoring will not be required to 

conduct additional monitoring to satisfy 

the requirement for ‘‘initial’’ 

monitoring. OSHA anticipates that this 

provision will reduce the compliance 

burden on employers who have already 

assessed exposure levels, since ‘‘initial’’ 

monitoring would not be required. The 

Agency believes the use of data obtained 

no more than 12 months prior to the 

effective date is appropriate, since 

samples taken more than 12 months 

before the effective date may not 

adequately represent current workplace 

conditions. The 12 month limit is 

consistent with the methylene chloride 

standard, 29 CFR 1910.1052. 

Second, to meet the requirement for 

an initial exposure assessment, the 

employer may, under paragraph 

(d)(2)(ii)(B), use objective data that 

demonstrate that respirable crystalline 

silica will not be released in airborne 

concentrations at or above the action 

level under any expected conditions of 

processing, use, or handling. Objective 

data must demonstrate that the work 

operation or the product may not 

reasonably be foreseen to release 

respirable crystalline silica in 

concentrations at or above the action 

level under any expected conditions of 

use. OSHA has allowed employers to 

use objective data in lieu of initial 

monitoring in other standards, such as 

formaldehyde (29 CFR 1910.1048) and 

asbestos (29 CFR 1910.1001). Any 

existing air monitoring data or objective 

data used in lieu of conducting initial 

monitoring must be maintained in 

accordance with the recordkeeping 

requirements in paragraph (j) of this 

standard. 

Paragraph (d)(3) of the proposed 

standard requires the employer to assess 

employee exposure to respirable 

crystalline silica on a periodic basis for 

employees exposed at or above the 

action level. If initial monitoring 

indicates that employee exposures are 

below the action level, the employer 

may discontinue monitoring for those 

employees whose exposures are 

represented by such monitoring. If the 

initial monitoring indicates employee 

exposure are at or above the action 

level, then the employer has the choice 

of following either a fixed schedule 

option or a performance option for 

periodic exposure assessments. 

The fixed schedule option in 

paragraph (d)(3)(i) specifies the 

frequency of monitoring based on the 

results of the initial and subsequent 

monitoring. If the initial monitoring 

indicates employee exposures to be at or 

above the action level but at or below 

the PEL, the employer must perform 

periodic monitoring at least every six 

months. If the initial or subsequent 

monitoring reveals employee exposures 

to be above the PEL, the employer must 

repeat monitoring at least every three 

months. If periodic monitoring results 

indicate that employee exposures have 

fallen below the action level, and those 

results are confirmed by a second 

measurement taken consecutively at 

least seven days afterwards, the 

employer may discontinue monitoring 

for those employees whose exposures 

are represented by such monitoring 

unless, under paragraph (d)(4), changes 

in the workplace result in new or 

additional exposures. 

OSHA recognizes that exposures in 

the workplace may fluctuate. Periodic 

monitoring provides the employer with 

assurance that employees are not 

experiencing exposures that are higher 

than expected and require the use of 

additional control measures. In 

addition, periodic monitoring reminds 

employees and employers of the 

continued need to protect against the 

hazards associated with exposure to 

respirable crystalline silica. 

Because of the fluctuation in 

exposures, OSHA believes that when 

initial monitoring results equal or 

exceed the action level, but are at or 

below the PEL, employers should 

continue to monitor employees to 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56448 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

ensure that exposures remain at or 

below the PEL. Likewise, when initial 

monitoring results exceed the PEL, 

periodic monitoring allows the 

employer to maintain an accurate 

profile of employee exposures. If the 

employer installs or upgrades controls, 

periodic monitoring will demonstrate 

whether or not controls are working 

properly. Selection of appropriate 

respiratory protection also depends on 

adequate knowledge of employee 

exposures. 

In general, the more frequently 

periodic monitoring is performed, the 

more accurate the employee exposure 

profile. Selecting an appropriate interval 

between measurements is a matter of 

judgment. OSHA believes that the 

proposed frequencies of six months for 

subsequent periodic monitoring for 

exposures at or above the action level 

but at or below the PEL, and three 

months for exposures above the PEL, 

provide intervals that are both practical 

for employers and protective for 

employees. This belief is supported by 

OSHA’s experience with comparable 

monitoring intervals in other standards, 

including those for cadmium (29 CFR 

1910.1027), methylenedianiline (29 CFR 

1910.1050), methylene chloride (29 CFR 

1910.1052), and formaldehyde (29 CFR 

1910.1048). 

OSHA recognizes that monitoring can 

be a time-consuming, expensive 

endeavor and therefore offers employers 

the incentive of discontinuing 

monitoring for employees whose 

sampling results indicate exposures are 

below the action level. Periodic 

monitoring for a specific worker or 

representative group of workers can be 

discontinued when at least two 

consecutive measurements taken at least 

seven days apart are below the action 

level, because this indicates a low 

probability that under the prevailing 

conditions exposure levels exceed the 

PEL. Therefore the final rule provides 

an incentive for employers to control 

their employees’ exposures to respirable 

crystalline silica to below the action 

level to minimize their exposure 

monitoring obligations while 

maximizing the protection of 

employees’ health. 

The performance option described in 

paragraph (d)(3)(ii) of the proposed 

standard provides employers flexibility 

to assess 8-hour TWA exposures on the 

basis of any combination of air 

monitoring data or objective data 

sufficient to accurately characterize 

employee exposures to respirable 

crystalline silica. OSHA recognizes that 

exposure monitoring may present 

challenges in certain instances, 

particularly when operations are of 

short duration or performed under 

varying environmental conditions. The 

performance option is intended to allow 

employers flexibility in performing 

periodic exposure assessments. Where 

the employer elects this option, the 

employer must conduct the exposure 

assessment prior to the time the work 

operation commences, and must 

demonstrate that employee exposures 

have been accurately characterized. 

Previous OSHA substance-specific 

health standards have usually allowed 

employers to use objective data to 

characterize employee exposures, but 

have generally limited its use to 

demonstrating that exposures would be 

below the action level (e.g., cadmium, 

29 CFR 1910.1027(d)(2)(iii)). In this 

instance, OSHA proposes to allow 

reliance on the use of objective data for 

periodic exposure assessments, even 

where exposures may exceed the action 

level or PEL. However, the burden is on 

the employer to show that the exposure 

assessment is sufficient to accurately 

characterize employee exposures to 

respirable crystalline silica. For 

example, where an employer has a 

substantial body of data (from previous 

monitoring, industry-wide surveys, or 

other sources) indicating that worker 

exposures in a given operation exceed 

the PEL, but do not exceed 10 times the 

PEL under any expected conditions, the 

employer may choose to rely on that 

data to determine his or her compliance 

obligations (e.g., implementation of 

feasible engineering and work practice 

controls, respiratory protection, medical 

surveillance). OSHA’s intent is to allow 

employers flexibility in methods used to 

assess employee exposures to respirable 

crystalline silica, but to ensure that the 

methods used are accurate in 

characterizing employee exposures. Any 

objective data relied upon must be 

maintained and made available in 

accordance with the recordkeeping 

requirements in paragraph (j)(2) of the 

proposed standard. 

Under paragraph (d)(4), the employer 

is required to reevaluate employee 

exposures whenever there has been a 

change in the production, process, 

control equipment, personnel, or work 

practices that may reasonably be 

expected to result in new or additional 

exposures to respirable crystalline silica 

at or above the action level. For 

example, if an employer has conducted 

monitoring during an operation while 

using local exhaust ventilation, and the 

flow rate of the ventilation system is 

decreased, then additional monitoring 

would be necessary to assess employee 

exposures under the modified 

conditions. In addition, there may be 

other situations which can result in new 

or additional exposures to respirable 

crystalline silica which are unique to an 

employee’s work situation. For instance, 

a worker may move from an open, 

outdoor location to an enclosed or 

confined space. Even though the task 

performed and materials used may 

remain constant, the changed 

environment could reasonably be 

expected to result in higher exposures to 

respirable crystalline silica. In order to 

cover those special situations, OSHA 

requires the employer to conduct an 

additional exposure assessment 

whenever a change may result in new or 

additional exposures at or above the 

action level. This reevaluation is 

necessary to ensure that the exposure 

assessment accurately represents 

existing exposure conditions. The 

exposure information gained from such 

assessments will enable the employer to 

take appropriate action to protect 

exposed employees, such as instituting 

additional engineering controls or 

providing appropriate respiratory 

protection. On the other hand, 

additional monitoring is not required 

simply because a change has been made, 

if the change is not reasonably expected 

to result in new or additional exposures 

to respirable crystalline silica at or 

above the action level. 

Paragraph (d)(5) of the proposed 

standard contains specifications for the 

methods to be used for sampling and 

analysis of respirable crystalline silica 

samples. OSHA has typically included 

specifications for the accuracy of 

exposure monitoring methods in 

substance specific standards, but not the 

specific analytical methods to be used 

or the qualifications of the laboratory 

that analyzes the samples. The proposed 

standard includes details regarding the 

specific sampling and analytical 

methods to be used, as well as the 

qualifications of the laboratories at 

which the samples are analyzed. As 

discussed in greater detail in the 

Technological Feasibility section of the 

Preliminary Economic Analysis, the 

Agency has preliminarily determined 

that these provisions are needed to 

ensure that monitoring can be relied 

upon to accurately measure employee 

exposures. 

Under proposed paragraph (d)(5)(i), 

all samples taken to satisfy the 

monitoring requirements of this section 

must be evaluated using the procedures 

specified in one of the following 

analytical methods: OSHA ID–142; 

NMAM 7500, NMAM 7602; NMAM 

7603; MSHA P–2; or MSHA P–7. OSHA 

has determined based on interlaboratory comparisons that laboratory 

analysis by either X-ray diffraction 

(XRD) or infrared (IR) spectroscopy is 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56449 

required to ensure the accuracy of the 

monitoring results in environments 

subject to the Agency’s jurisdiction. The 

specified analytical methods are the 

XRD or IR methods for analysis of 

respirable crystalline silica that have 

been established by OSHA, NIOSH, or 

MSHA. 

To ensure the accuracy of air 

sampling data relied on by employers to 

achieve compliance with standard, the 

standard requires that air samples are to 

be analyzed only at accredited 

laboratories that meet six requirements 

listed in paragraphs (d)(5)(ii)(A–F). The 

requirements were developed based on 

procedures implemented at laboratories 

that have achieved acceptable levels of 

accuracy and precision during a study 

of inter-laboratory variability. An 

employer who engages an independent 

laboratory to analyze respirable 

crystalline silica samples could rely on 

an assurance from that laboratory that 

the specified requirements were met. 

For example, the laboratory could 

include a statement that it complied 

with the requirements of the standard 

along with the sampling results 

provided to the employer. 

Paragraph (d)(5)(ii)(A) requires 

employers to ensure that samples taken 

to monitor employee exposures are 

analyzed by a laboratory that is 

accredited to ANS/ISO/IEC Standard 

17025 ‘‘General requirements for the 

competence of testing and calibration 

laboratories’’ (EN ISO/IEC 17025:2005) 

by an accrediting organization that can 

demonstrate compliance with the 

requirements of ISO/IEC 17011 

‘‘Conformity assessment—General 

requirements for accreditation bodies 

accrediting conformity assessment 

bodies’’ (EN ISO/IEC 17011:2004). ANS/ 

ISO/IEC 17025 is a consensus standard 

that was developed by the International 

Organization for Standardization and 

the International Electrotechnical 

Commission (ISO/IEC) and approved by 

the American Society for Testing and 

Materials (ASTM). This standard 

establishes criteria by which 

laboratories can demonstrate 

proficiency in conducting laboratory 

analysis through the implementation of 

quality control measures. To 

demonstrate competence, laboratories 

must implement a quality control (QC) 

program that evaluates analytical 

uncertainty and provides employers 

with estimates of sampling and 

analytical error (SAE) when reporting 

samples. ISO/IEC 17011 establishes 

criteria for organizations that accredit 

laboratories under ISO/IEC 17025. For 

example, the AIHA accredits 

laboratories for proficiency in the 

analysis of crystalline silica using 

criteria based on the ISO 17025 and 

other criteria appropriate for the scope 

of the accreditation. 

Paragraphs (d)(5)(ii)(B)–(F) contain 

additional requirements for laboratories 

that have been demonstrated to improve 

accuracy and reliability through interlaboratory comparisons. The laboratory 

must participate in a round robin testing 

program with at least two other 

independent laboratories at least every 

six months. An example of a testing 

program that satisfies this requirement, 

as it is currently implemented, is the 

program established by AIHA 

Proficiency Analytical Testing 

Programs, LLC. The laboratory must use 

the most current National Institute of 

Standards and Technology (NIST) or 

NIST traceable standards for instrument 

calibration or instrument calibration 

verification. The laboratory must have 

an internal quality control (QC) program 

that evaluates analytical uncertainty and 

provides employers with estimates of 

sampling and analytical error. The 

laboratory must characterize the sample 

material by identifying polymorphs of 

respirable crystalline silica present, 

identifying the presence of any 

interfering compounds that might affect 

the analysis, and making the corrections 

necessary in order to obtain accurate 

sample analysis. The laboratory must 

analyze quantitatively for respirable 

crystalline silica only after confirming 

that the sample matrix is free of 

uncorrectable analytical interferences, 

and corrects for analytical interferences. 

The laboratory must perform routine 

calibration checks with standards that 

bracket the sample concentrations using 

five or more calibration standard levels 

to prepare calibration curves, and use 

instruments optimized to obtain a 

quantitative limit of detection that 

represents a value no higher than 25 

percent of the PEL. 

Under paragraph (d)(6) of the 

proposed rule, employers covered by 

the general industry standard must 

notify each affected employee within 15 

working days of completing an exposure 

assessment. Notification is required 

whenever an exposure assessment has 

been conducted regardless of whether or 

not employee exposure exceeds the 

action level or PEL. In construction, 

employers must notify each affected 

employee not more than five working 

days after the exposure assessment has 

been completed. A shorter time period 

for notification is provided in 

construction in recognition of the often 

short duration of operations and 

employment in particular locations in 

this sector. The time allowed for 

notification is consistent with the 

harmonized notification times 

established for certain health standards 

applicable to general industry and 

construction in Phase II of OSHA’s 

Standards Improvement Project. 70 FR 

1112; January 5, 2005. Where the 

employer follows the scheduled 

monitoring option provided for in 

paragraph (d)(3)(i), the 15 (or five) day 

period for notification commences when 

monitoring results are received by the 

employer. For employers following the 

performance-oriented option under 

paragraph (d)(3)(ii), the period 

commences when the employer makes a 

determination of the exposure levels 

and the need for corresponding control 

measures (i.e., prior to the time the work 

operation commences, and whenever 

exposures are re-evaluated). 

The notification requirements in this 

provision apply to all employees for 

which an exposure assessment has been 

conducted, either individually or as part 

of a representative monitoring strategy. 

It includes employees who were subject 

to personal monitoring, as well as 

employees whose exposure was 

assessed based on other employees who 

were sampled, and employees whose 

exposures have been assessed on the 

basis of objective data. The employer 

shall either notify each affected 

employee in writing or post the 

monitoring results in an appropriate 

location accessible to all affected 

employees. In addition, paragraph 

(d)(6)(ii) requires that whenever the PEL 

has been exceeded, the written 

notification must contain a description 

of the corrective action(s) being taken by 

the employer to reduce employee 

exposures to or below the PEL. The 

requirement to inform employees of the 

corrective actions the employer is taking 

to reduce the exposure level to or below 

the PEL is necessary to assure 

employees that the employer is making 

efforts to furnish them with a safe and 

healthful work environment, and is 

required under section 8(c)(3) of the 

OSH Act. 29 U.S.C. 657(c)(3). 

Notifying employees of their 

exposures provides them with 

knowledge that can permit and 

encourage them to be more proactive in 

working to control their own exposures 

through better and safer work practices 

and more active participation in safety 

programs. As OSHA noted with respect 

to its Hazard Communication Standard: 

‘‘Workers provided the necessary hazard 

information will more fully participate 

in, and support, the protective measures 

instituted in their workplaces.’’ 59 FR 

6126, 6127; Feb. 9, 1994. Exposures to 

respirable crystalline silica below the 

PEL may still be hazardous, and making 

employees aware of such exposures may 

encourage them to take whatever steps 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56450 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

they can, as individuals, to reduce their 

exposures as much as possible. 

Paragraph (d)(7) requires the 

employer to provide affected employees 

or their designated representatives an 

opportunity to observe any air 

monitoring of employee exposure to 

respirable crystalline silica, whether the 

employer uses the fixed schedule option 

or the performance option. When 

observation of monitoring requires entry 

into an area where the use of protective 

clothing or equipment is required, the 

employer must provide the observer 

with that protective clothing or 

equipment, and assure that the observer 

uses such clothing or equipment. 

The requirement for employers to 

provide employees or their 

representatives the opportunity to 

observe monitoring is consistent with 

the OSH Act. Section 8(c)(3) of the OSH 

Act mandates that regulations 

developed under section 6 of the Act 

provide employees or their 

representatives with the opportunity to 

observe monitoring or measurements. 29 

U.S.C. 657(c)(3). Also, section 6(b)(7) of 

the OSH Act states that, where 

appropriate, OSHA standards are to 

prescribe suitable protective equipment 

to be used in dealing with hazards. 29 

U.S.C. 655(b)(7). The provision for 

observation of monitoring and 

protection of the observers is also 

consistent with OSHA’s other 

substance-specific health standards 

such as those for cadmium (29 CFR 

1910.1027) and methylene chloride (29 

CFR 1910.1052). 

Table 1 in paragraph (f) of the 

proposed construction standard lists 

exposure control methods for selected 

construction operations. As discussed 

with regard to paragraph (f), OSHA has 

preliminarily determined that the 

engineering controls, work practices, 

and respiratory protection specified for 

each operation in Table 1 represent 

appropriate and effective controls for 

those operations. Therefore, paragraph 

(d)(8) of the proposed construction 

standard makes an exception to the 

general requirement for exposure 

assessment where employees perform 

operations in Table 1 and the employer 

has fully implemented the controls 

specified for that operation. This 

relieves the employer of the burden of 

performing exposure monitoring in 

these situations. 

Where the employer elects to 

implement the control measures 

specified in Table 1 for a given 

construction operation, paragraph 

(d)(8)(ii) requires that the employer 

presume that each employee performing 

an operation listed in Table 1 that 

requires a respirator is exposed above 

the PEL, unless the employer can 

demonstrate otherwise in accordance 

with paragraph (d) of the proposed rule. 

So, for example, if an employer elects to 

implement the controls specified in 

Table 1 for a given construction 

operation that requires a respirator and 

does not conduct an exposure 

assessment to demonstrate that 

exposures are below the PEL, the 

employer would be required to provide 

each employee performing that 

operation for 30 or more days per year 

with medical surveillance in accordance 

with paragraph (h) of the proposed rule. 

(e) Regulated Areas and Access Control 

Under paragraph (e)(1) in the 

standards, employers have two options 

wherever an employee’s exposure to 

airborne concentrations of respirable 

silica is, or can reasonably be expected 

to be, in excess of the PEL: (1) the 

establishment of regulated areas in 

accordance with paragraph (e)(2); or (2) 

the implementation of a written access 

control plan in accordance with 

paragraph (e)(3). 

The purpose of a regulated area is to 

ensure that the employer makes 

employees aware of the presence of 

respirable crystalline silica at levels 

above the PEL, and to limit exposure to 

as few employees as possible. The 

establishment of a regulated area is an 

effective means of minimizing exposure 

to employees not directly involved in 

operations that generate respirable 

crystalline silica and limiting the risk of 

exposure to a substance known to cause 

adverse health effects. Because of the 

potentially serious results of exposure 

and the need for persons entering the 

area to be properly protected, the 

number of persons given access to the 

area should be limited to those 

employees needed to perform the job. 

Limiting access to regulated areas also 

has the benefit of reducing the 

employer’s obligation to implement 

other provisions of this proposed 

standard to as few employees as 

possible. 

Under paragraph (e)(2)(ii), regulated 

areas are to be demarcated from the rest 

of the workplace in any manner that 

adequately establishes and alerts 

employees to the boundary of the 

regulated area, and minimizes the 

number of employees exposed to 

respirable crystalline silica within the 

regulated area. OSHA has not specified 

how employers are to demarcate 

regulated areas. Signs, barricades, lines, 

or textured flooring may each be 

effective means of demarcating the 

boundaries of regulated areas. 

Permitting employers to choose how 

best to identify and limit access to 

regulated areas is consistent with 

OSHA’s belief that employers are in the 

best position to make such 

determinations, based on their 

knowledge of the specific conditions of 

their workplaces. Whatever methods are 

chosen to establish a regulated area, the 

demarcation must effectively warn 

employees not to enter the area unless 

they are authorized, and then only if 

they are using the proper personal 

protective equipment. Allowing 

employers to demarcate and limit access 

to the regulated areas as they choose is 

consistent with recent OSHA substancespecific health standards, such as 

chromium (VI) (29 CFR 1910.1026) and 

1,3-butadiene (29 CFR 1910.1051). 

Paragraph (e)(2)(iii) describes who 

may enter regulated areas. In both 

standards, access to regulated areas is 

restricted to persons required by their 

job duties to be present in the area, as 

authorized by the employer. In addition, 

designated employee representatives 

exercising the right to observe 

monitoring procedures are allowed to 

enter regulated areas. For example, 

employees in some workplaces may 

designate a union representative to 

observe monitoring; this person would 

be allowed to enter the regulated area. 

Persons authorized under the OSH Act, 

such as OSHA compliance officers, are 

also allowed access to regulated areas. 

Under paragraph (e)(2)(iv), employers 

must provide each employee and 

designated representative who enters a 

regulated area with an appropriate 

respirator in accordance with paragraph 

(g), and require that the employee or 

designated representative uses the 

respirator while in the regulated area. 

The boundary of the regulated area 

indicates where respirators must be 

donned prior to entering, and where 

respirators can be doffed, or removed, 

upon exiting the regulated area. This 

provision is intended to establish a clear 

and consistent requirement for 

respirator use for all employees who 

enter a regulated area, regardless of the 

duration of their presence in the 

regulated area. OSHA believes this 

proposed requirement is simple to 

administer and enforce, protective of 

employee health, and consistent with 

general practice in management of 

regulated areas. 

OSHA has proposed a requirement for 

use of protective clothing or other 

measures to limit contamination of 

clothing for employees working in 

regulated areas. Paragraph (e)(2)(v) 

requires that, where there is the 

potential for employees’ work clothing 

to become grossly contaminated with 

finely divided material containing 

crystalline silica, the employer must 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56451 

either provide appropriate protective 

clothing such as coveralls or similar 

full-bodied clothing, or else provide a 

means to remove excessive silica dust 

from contaminated clothing when 

exiting the regulated area. This 

provision is intended to limit additional 

respirable crystalline exposures to 

employees in regulated areas that could 

result from disturbing the dust that has 

accumulated on their clothing. It is also 

intended to protect employees in 

adjacent areas from exposures that 

could occur if employees with grossly 

contaminated clothing were to carry 

crystalline silica dust to other areas of 

the workplace. The purpose of this 

provision is not, however, to protect 

employees from dermal exposure to 

crystalline silica, as discussed further 

below. 

In paragraph (e)(2)(v)(A), the proposal 

refers to ‘‘finely divided materials.’’ 

When using this term, the proposed 

standard refers to particles with very 

small diameters (i.e., ≤ 10 mm) such that, 

once airborne, the particles would be 

considered respirable dust. ‘‘Gross 

contamination’’ refers to a substantial 

accumulation of dust on clothing worn 

by an employee working in a regulated 

area such that movement by the 

individual results in the release of dust 

from the clothing. The provision is not 

intended to cover any contamination of 

clothing, but rather those limited 

circumstances where significant 

quantities of dust are deposited on 

workers’ clothing. Where such 

conditions exist, OSHA anticipates that 

the dust present on workers’ clothing or 

the release of dust from the clothing 

would be plainly visible. 

Under paragraphs (e)(2)(v)(A)(1)–(2), 

the employer would have the option of 

providing either appropriate protective 

clothing, such as coveralls that can be 

removed upon exiting the regulated 

area, or any other means of removing 

excessive silica dust from contaminated 

clothing that minimizes employee 

exposure to respirable crystalline silica. 

The employer may choose the approach 

that works best in the circumstances 

found in a particular workplace. The 

employer may choose, for example, to 

provide HEPA vacuums for removal of 

dust from clothing. It should be noted, 

however, that paragraph (f)(3)(ii) 

(paragraph(f)(4)(ii) of the standard for 

construction) prohibits the use of 

compressed air, dry sweeping, and dry 

brushing to clean clothing or surfaces 

contaminated with crystalline silica 

where such activities could contribute 

to employee exposure to respirable 

crystalline silica that exceeds the PEL. 

Paragraph (e)(2)(v) requires 

contaminated clothing to be either 

cleaned or removed upon exiting the 

regulated area, in order to ensure that 

other areas of the workplace do not 

become contaminated. Cleaning or 

removal of contaminated clothing must 

take place prior to removal of 

respiratory protection in order to ensure 

that any exposure to dust released from 

contaminated clothing is minimized. 

In other substance-specific chemical 

standards, OSHA has typically included 

requirements for provision of protective 

clothing, as well as associated 

provisions addressing removal, storage, 

cleaning, and replacement of protective 

clothing. The proposed provisions for 

this respirable crystalline standard are 

more limited than other OSHA 

standards, in that the requirements only 

apply in regulated areas, and then only 

when there is the potential for clothing 

to become grossly contaminated. The 

employer is also given the option of 

providing other means to remove dust 

from contaminated clothing, an 

alternative not generally available in 

other OSHA standards. OSHA has 

proposed these more limited provisions 

because the Agency has made a 

preliminary determination that the 

proposed provisions will serve to 

reduce employee exposures, and that 

additional requirements for protective 

clothing are not reasonably necessary 

and appropriate. 

Most other chemicals regulated under 

OSHA substance-specific standards 

either have direct dermal effects or can 

contribute to overall exposures through 

dermal absorption. OSHA is not aware 

of any evidence that dermal exposure is 

a concern for respirable crystalline 

silica. Moreover, dusts containing 

crystalline silica are ubiquitous in many 

of the work environments covered by 

this proposed standard. Therefore, the 

proposed silica standard focuses on 

those situations where contamination of 

clothing has the potential to contribute 

significantly to employee inhalation 

exposures. OSHA recognizes that the 

ASTM standards addressing 

occupational exposure to respirable 

crystalline silica do not include 

requirements for protective clothing. 

However, the Agency believes that the 

proposed provisions will serve to limit 

employee exposures in those situations 

where contamination of clothing 

contributes to inhalation exposures. 

OSHA also notes that the Agency’s 

Advisory Committee on Construction 

Safety and Health recommended that 

OSHA maintain the language on 

protective clothing that was included in 

the draft provided for review under the 

Small Business Regulatory Enforcement 

Fairness Act (SBREFA). The SBREFA 

draft language would have required 

protective clothing or a means to 

vacuum contaminated clothing for all 

employees exposed above the PEL. The 

Agency seeks comment on the proposed 

provisions for protective clothing and 

has included this topic in the ‘‘Issues’’ 

section of this preamble. 

OSHA’s standard addressing 

sanitation in general industry (29 CFR 

1910.141) requires that whenever 

employees are required by a particular 

standard to wear protective clothing 

because of the possibility of 

contamination with toxic materials, 

change rooms equipped with storage 

facilities for street clothes and separate 

storage facilities for protective clothing 

shall be provided (29 CFR 1910.141(e)). 

The sanitation standard also includes 

provisions for lavatories with running 

water (29 CFR 1910.141(d)(2)), and 

prohibits storage or consumption of 

food or beverages in any area exposed 

to a toxic material (29 CFR 

1910.141(g)(2)). Similar provisions are 

in place for construction (29 CFR 

1926.51). OSHA expects that employers 

will comply with the provisions of the 

sanitation standard when required. 

Thus, no additional requirements for 

hygiene practices are included in the 

proposed silica standards. 

The proposed standard provides two 

options for employers to choose 

between for minimizing exposure to 

employees not directly involved in 

operations that generate respirable 

crystalline silica. The establishment of 

regulated areas under paragraph (e)(2), 

as described above, is the first option for 

exposure control in workplaces, and 

when fully implemented will satisfy 

this requirement. However, OSHA 

recognizes that establishing regulated 

areas in some workplaces can be 

difficult. For example, in the SBREFA 

review process, the question was raised 

as to how a regulated area could be 

established for a highway project, where 

the source of exposure could be 

constantly moving. Some activities 

covered by the general industry/

maritime standard may present similar 

difficulties, such as hydraulic fracturing 

operations where exposures may occur 

over a large area. In recognition of the 

practical problems that may be 

encountered in such circumstances, the 

proposed standard includes an option in 

paragraph (e)(3) for establishing and 

implementing a written access control 

plan in lieu of a regulated area. 

Paragraph (e)(3)(ii) in the standard 

sets out the requirements for a written 

access control plan. The plan must 

contain provisions for a competent 

person to identify the presence and 

location of any areas where respirable 

crystalline silica exposures are, or can 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56452 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

reasonably be expected to be, in excess 

of the PEL. It must describe how 

employees will be notified of the 

presence and location of areas where 

exposures are, or can reasonably be 

expected to be, in excess of the PEL, and 

how these areas will be demarcated 

from the rest of the workplace. For 

multi-employer workplaces, the plan 

must identify the methods that will be 

used to inform other employers of the 

presence and the location of areas where 

respirable crystalline silica exposures 

are, or can reasonably be expected to be, 

in excess of the PEL, and any 

precautionary measures that need to be 

taken to protect employees. The written 

plan must contain provisions for 

limiting access to these areas, in order 

to minimize the number of employees 

exposed and the level of employee 

exposure. The plan must also describe 

procedures for providing each employee 

working in areas where respirable 

crystalline silica exposures are, or can 

reasonably be expected to be, in excess 

of the PEL with an appropriate 

respirator in accordance with paragraph 

(g) of this section. Where there is the 

potential for employees’ work clothing 

to become grossly contaminated with 

finely divided material containing 

crystalline silica, the access control plan 

must include provisions for the 

employer to provide either appropriate 

protective clothing, or a means to 

remove excessive silica dust from 

contaminated clothing that minimizes 

employee exposure to respirable 

crystalline silica. The access control 

plan must also include provisions for 

removal or cleaning of such clothing. 

The employer must review and 

evaluate the effectiveness of the written 

access control plan at least annually and 

update it as necessary. The written 

access control plan must be available for 

examination and copying, upon request, 

to employees, their designated 

representatives, the Assistant Secretary 

and the Director. 

The intent of the provision for 

establishing written access control plans 

in lieu of regulated areas is to provide 

employers with flexibility to adapt to 

the particular circumstances of their 

worksites while maintaining equivalent 

protection for employees. The Agency 

seeks comment on this proposed 

approach and has included this topic in 

the ‘‘Issues’’ section of this preamble. 

(f) Methods of Compliance 

Paragraph (f)(1) of the proposed rule 

establishes a hierarchy of controls 

which employers must use to reduce 

and maintain exposures to respirable 

crystalline silica to or below the 

permissible exposure limit (PEL). The 

proposed rule requires employers to 

implement engineering and work 

practice controls as the primary means 

to reduce exposure to the PEL or to the 

lowest feasible level above the PEL. In 

situations where engineering and work 

practice controls are not sufficient to 

reduce exposures to or below the PEL, 

employers are required to supplement 

these controls with respiratory 

protection, according to the 

requirements of paragraph (g) of the 

proposed rule. OSHA proposes to 

require primary reliance on engineering 

controls and work practices because 

reliance on these methods is consistent 

with good industrial hygiene practice, 

with the Agency’s experience in 

ensuring that workers have a healthy 

workplace, and with the Agency’s 

traditional adherence to a hierarchy of 

preferred controls. 

OSHA requires adherence to this 

hierarchy of controls in a number of 

current standards, including the Air 

Contaminants (29 CFR 1910.1000) and 

Respiratory Protection (29 CFR 

1910.134) standards, as well as previous 

substance-specific standards. The 

Agency’s adherence to the hierarchy of 

controls has been successfully upheld 

by the courts (see AFL–CIO v. Marshall, 

617 F.2d 636 (D.C. Cir. 1979) (cotton 

dust standard); United Steelworkers v. 

Marshall, 647 F.2d 1189 (DC Cir. 1980), 

cert. denied, 453 U.S. 913 (1981) (lead 

standard); ASARCO v. OSHA, 746 F.2d 

483 (9th Cir. 1984) (arsenic standard); 

Am. Iron & Steel v. OSHA, 182 F.3d 

1261 (11th Cir. 1999) (respiratory 

protection standard); Pub. Citizen v. 

U.S. Dep’t of Labor, 557 F.3d 165 (3rd 

Cir. 2009) (hexavalent chromium 

standard)). 

The Agency understands that 

engineering controls: (1) Control 

crystalline silica-containing dust 

particles at the source; (2) are reliable, 

predictable, and provide consistent 

levels of protection to a large number of 

workers; (3) can be monitored 

continually and relatively easily; and (4) 

are not as susceptible to human error as 

is the use of personal protective 

equipment. The use of engineering 

controls to prevent the release of silicacontaining dust particles at the source 

also minimizes the silica exposure of 

other employees in surrounding work 

areas, especially at construction sites, 

who are not directly involved in the task 

that is generating the dust, and may not 

be wearing respirators. 

Respirators are another important 

means of protecting workers from 

exposure to air contaminants. However, 

to be effective, respirators must be 

individually selected; fitted and 

periodically refitted; conscientiously 

and properly worn; regularly 

maintained; and replaced as necessary. 

In many workplaces, these conditions 

for effective respirator use are difficult 

to achieve. The absence of any one of 

these conditions can reduce or eliminate 

the protection the respirator provides to 

some or all of the employees. For 

example, certain types of respirators 

require the user to be clean shaven to 

achieve an effective seal where the 

respirator contacts the worker’s skin. 

Failure to ensure a tight seal due to the 

presence of facial hair compromises the 

effectiveness of the respirator. 

Respirator effectiveness ultimately 

relies on the good work practices of 

individual employees. In contrast, the 

effectiveness of engineering controls 

does not rely so heavily on actions of 

individual employees. Engineering and 

work practice controls are capable of 

reducing or eliminating a hazard from 

the workplace as a whole, while 

respirators protect only the employees 

who are wearing them correctly. 

Furthermore, engineering and work 

practice controls permit the employer to 

evaluate their effectiveness directly 

through air monitoring and other means. 

It is considerably more difficult to 

directly measure the effectiveness of 

respirators on a regular basis to ensure 

that employees are not unknowingly 

being overexposed. OSHA therefore 

considers the use of respirators to be the 

least satisfactory approach to exposure 

control. 

In addition, use of respirators in the 

workplace presents other safety and 

health concerns. Respirators can impose 

substantial physiological burdens on 

employees, including the burden 

imposed by the weight of the respirator; 

increased breathing resistance during 

operation; limitations on auditory, 

visual, and odor sensations; and 

isolation from the workplace 

environment. Job and workplace factors 

such as the level of physical work effort, 

the use of protective clothing, and 

temperature extremes or high humidity 

can also impose physiological burdens 

on workers wearing respirators. These 

stressors may interact with respirator 

use to increase the physiological strain 

experienced by employees. 

Certain medical conditions can 

compromise an employee’s ability to 

tolerate the physiological burdens 

imposed by respirator use, thereby 

placing the employee wearing the 

respirator at an increased risk of illness, 

injury, and even death. These medical 

conditions include cardiovascular and 

respiratory diseases (e.g., a history of 

high blood pressure, angina, heart 

attack, cardiac arrhythmias, stroke, 

asthma, chronic bronchitis, 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56453 

emphysema), reduced pulmonary 

function caused by other factors (e.g., 

smoking or prior exposure to respiratory 

hazards), neurological or 

musculoskeletal disorders (e.g., 

epilepsy, lower back pain), and 

impaired sensory function (e.g., a 

perforated ear drum, reduced olfactory 

function). Psychological conditions, 

such as claustrophobia, can also impair 

the effective use of respirators by 

employees and may also cause, 

independent of physiological burdens, 

significant elevations in heart rate, 

blood pressure, and respiratory rate that 

can jeopardize the health of employees 

who are at high risk for 

cardiopulmonary disease. 

These concerns about the burdens 

placed on workers by the use of 

respirators were acknowledged in 

OSHA’s revision of its Respiratory 

Protection standard, and are the basis 

for the requirement that employers 

provide a medical evaluation to 

determine the employee’s ability to 

wear a respirator before the employee is 

fit tested or required to use a respirator 

in the workplace (63 FR 1152, Jan. 8, 

1998). Although experience in industry 

shows that most healthy workers do not 

have physiological problems wearing 

properly chosen and fitted respirators, 

nonetheless common health problems 

can cause difficulty in breathing while 

an employee is wearing a respirator. 

In addition, safety problems created 

by respirators that limit vision and 

communication must always be 

considered. In some difficult or 

dangerous jobs, effective vision or 

communication is vital. Voice 

transmission through a respirator can be 

difficult, annoying, and fatiguing. In 

addition, movement of the jaw in 

speaking can cause leakage, thereby 

reducing the efficiency of the respirator 

and decreasing the protection afforded 

the employee. Skin irritation can result 

from wearing a respirator in hot, humid 

conditions. Such irritation can cause 

considerable distress to workers and can 

cause workers to refrain from wearing 

the respirator, thereby rendering it 

ineffective. 

While OSHA acknowledges that 

certain types of respirators may lessen 

problems associated with breathing 

resistance and skin discomfort, OSHA 

does not believe that respirators provide 

employees with a level of protection 

that is equivalent to engineering 

controls, regardless of the type of 

respirator used. It is well-recognized 

that certain types of respirators are 

superior to other types of respirators 

with regard to the level of protection 

offered, or impart other advantages. 

OSHA has evaluated the level of 

protection offered by different types of 

respirators in the Agency’s Assigned 

Protection Factors rulemaking (68 FR 

34036, June 6, 2003). Even in situations 

where engineering controls are not 

sufficiently effective to reduce exposure 

levels to or below the PEL, the reduction 

in exposure levels benefits workers by 

reducing the required protection factor 

of the respirator, which provides a 

wider range of options in the type of 

respirators that can be used. For 

example, for situations in which dust 

concentrations are reduced through use 

of engineering controls to levels that are 

less than ten times the PEL, employers 

would have the option of providing 

approved half-mask respirators that may 

be lighter and easier to use when 

compared with full-facepiece 

respirators. 

In summary, engineering and work 

practice controls are capable of reducing 

or eliminating a hazard from the 

workplace; respirators protect only the 

employees who are wearing them. In 

addition, the effectiveness of respiratory 

protection always depends on the 

actions of employees, while the efficacy 

of engineering controls is generally 

independent of the individual. OSHA 

believes that engineering controls offer 

more reliable and consistent protection 

to a greater number of workers, and are 

therefore preferable to respiratory 

protection. Engineering controls. The 

engineering controls presented in this 

proposal can be grouped into these main 

categories: (1) Substitution, (2) isolation, 

(3) ventilation, and (4) dust suppression. 

Depending on the sources of crystalline 

silica dust and the operations 

conducted, a combination of control 

methods may reduce silica exposure 

levels more effectively than a single 

method. Substitution. Substitution 

refers to the replacement of a toxic 

material with another material that 

reduces or eliminates the harmful 

exposure. OSHA considers substitution 

to be an ideal control measure if it 

replaces a toxic material in the work 

environment with a non-toxic material, 

thus eliminating the risk of adverse 

health effects. 

The technological feasibility study 

(PEA, Chapter 4) indicates that 

employers use substitutes for crystalline 

silica in a variety of operations. For 

example, some employers use 

substitutes in abrasive blasting 

operations, repair and replacement of 

refractory materials, operations 

performed in foundries, and in the 

railroad transportation industry. If 

substitutes for crystalline silica are 

being used in any operation not 

considered in the feasibility study, 

OSHA is requesting relevant 

information that contains data 

supporting the effectiveness, in 

reducing exposure to crystalline silica, 

of substitutes currently being used. 

Before replacing a toxic material with 

a substitute, it is important that 

employers evaluate the toxicity of the 

substitute materials relative to the 

toxicity of the original material. 

Substitute materials that pose 

significant new or additional risks to 

workers are not a desirable means of 

control. Additionally, employers must 

comply with Section 5(a)(1) of the OSH 

Act, which prohibits occupational 

exposure to ‘‘recognized hazards that 

are causing or are likely to cause death 

or serious physical harm.’’ 29 U.S.C. 

654(a)(1). Employers must also comply 

with applicable standards. 29 U.S.C. 

654(a)(2). For example, with respect to 

chemical hazards, OSHA’s Hazard 

Communication standard imposes 

specific requirements for employee 

training, material safety data sheets, and 

labeling. 29 CFR 1910.1200. 

While the Agency’s technological 

feasibility analysis includes information 

about materials that some employers use 

as alternatives to silica or silicacontaining materials, the Agency 

recognizes that these substitute 

materials may present health risks. 

OSHA does not intend to imply that any 

particular material is an appropriate or 

safe substitute for silica. Isolation. 

Isolation, by means of a process 

enclosure, is another effective 

engineering control employed to reduce 

exposures to crystalline silica. It refers 

to a physical barrier normally 

surrounding the source of exposure and 

installed to contain a toxic substance 

within the barrier. Isolating the source 

of a hazard within an enclosure restricts 

respirable dust from spreading 

throughout a workplace and exposing 

workers who are not directly involved 

in dust-generating operations. 

Due to the shift from manually 

operated to automated processes, 

enclosures have become more 

practicable. For example, forming line 

operators in structural clay products 

manufacturing can use automation for 

transfer of materials, allowing conveyors 

and milling areas to be enclosed (OSHA 

SEP Inspection Report 300523396). 

Another example can be observed in 

automated refractory demolition and 

installation methods. A ‘‘pusher’’ 

system installed in coreless induction 

furnaces allows refractory linings to be 

automatically pressed out by push 

plates installed in furnace bottoms. A 

representative of Foundry Products 

Supplier B (2000a) estimated that total 

worker exposure using a pusher system 

would be roughly half that of traditional 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56454 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

chipping refractory removal methods 

and possibly as much as 80 percent less 

if an enclosure (tarp) was used over the 

end of the furnace from which the lining 

is extruded. At a pottery facility, the 

exposure for a material handler 

monitoring automated equipment that is 

adding silica-containing raw materials 

to a mixer was about 66 percent lower 

than the exposure of a material handler 

manually adding the material to the 

mixer (OSHA SEP Inspection Report 

300384435). At a structural clay 

industry facility inspected by OSHA, an 

86-percent reduction in respirable 

quartz exposure readings occurred after 

management installed an enclosed, 

automated sand transfer system, despite 

not having optimally sealed components 

(PEA, Chapter 4). 

Workers can also be isolated from a 

hazardous source when they operate 

heavy machinery equipped with 

enclosed cabs. In such cases, a cab that 

is well sealed and equipped with 

ventilation and a high-efficiency 

particulate air (HEPA) filter can 

minimize the potential for exposure 

from the dust created outside the cab. 

MSHA (1997) recommended the 

following controls to maximize the 

effectiveness of an enclosed cab: 

keeping the cab interior’s horizontal and 

vertical surfaces and areas clean and 

free of debris; inspecting door seals and 

closing mechanisms to ensure they work 

properly; ensuring that seals around 

windows, power line entries, and joints 

in the walls and floors of the cab are 

tightly sealed; ensuring that air 

conditioners are designed so that air 

comes in from the outdoors to create 

positive pressure and passes first 

through a pre-filter (those with an 

American Society of Heating, 

Refrigeration and Air-Conditioning 

Engineers efficiency rating of 90 percent 

are common) and then through a HEPA 

filter; and ensuring that HEPA filters are 

changed when they reach the 

manufacturer’s final resistance value 

(MSHA, 1997). 

Tractors, front-end loaders, and other 

mobile material-handling equipment 

equipped with properly enclosed, 

sealed, and ventilated operator cabs 

(i.e., no leaks, positive pressure, and 

effective air filtration) can substantially 

reduce silica exposures associated with 

the use of such equipment. Directreading instruments show that fine 

particle (0.3 micron (mm) in size) 

concentrations inside operator cabs can 

be reduced by an average of 96 percent 

when cabs are clean, sealed, and have 

a functionally adequate filtration and 

pressurization system. Gravimetric 

sampling instruments found an average 

cab efficiency of about 93 percent when 

comparing dust levels outside and 

inside the cab (Cecala et al., 2005). 

Similarly, NIOSH investigators reported 

respirable dust exposure reductions of 

97 and 98 percent, respectively, inside 

the cabin of a modified railroad ballast 

dumper in the railroad transportation 

industry (NIOSH HHE 92–0311, 2001). 

Other researchers have reported particle 

reductions inside the operator cab 

greater than 90 percent (Hall et al., 

2002). 

The Agency recognizes that although 

enclosed cabs have been proven to be an 

effective control method, they do not 

control exposures at the source. In many 

circumstances, machine operators work 

alongside employees who are outside 

the enclosed cabs and are not protected 

by them. As such, OSHA expects 

employers to apply all other feasible 

controls to protect those employees. 

In certain situations, a process 

enclosure can enhance the benefits of 

other control methods when used 

simultaneously, such as when an 

enclosure is equipped with local 

exhaust ventilation (LEV). When the 

enclosure contains the crystalline-silicacontaining dust cloud, the ventilation 

system is able to remove that 

contaminant in a more effective and 

timely fashion, as opposed to having it 

dissipate out of the ventilation system’s 

exhaust range where there is no 

enclosure. 

In the asphalt roofing manufacturing 

industry, the capture of process 

emissions (including dust) at the coater 

station is best achieved by using LEV in 

conjunction with an enclosure. When 

using a full enclosure with LEV, NIOSH 

recommends several practices that 

improve the capture efficiency of the 

ventilation system. OSHA believes these 

recommendations are beneficial 

whenever this control method is used in 

a production line. The 

recommendations are: (1) When process 

enclosures are used, the number and 

size of openings in the enclosure must 

be minimized to prevent a reduction in 

the capture efficiency of the ventilation 

system; (2) all doors should be 

adequately sealed and closed during 

operation of the line; (3) the size of the 

opening where the product enters and 

leaves the process equipment should be 

minimized to ensure an inward flow of 

air by the negative pressure within the 

enclosure; and (4) negative pressure 

must be maintained inside the enclosure 

to prevent leakage of process emissions 

into the workplace. 

In the foundry industry, shakeout 

operators are responsible for monitoring 

equipment that separates the casting 

being produced from the molding 

material. This process generally 

involves shaking the casting, which 

creates dust exposure associated with 

respirable crystalline silica levels above 

the PEL. OSHA has determined that 

employers using this process should 

enclose the shakeout operations, and the 

most effective method to reduce 

exposure is installing efficient 

ventilation (PEA, Chapter 4). 

Another example occurs in the 

masonry industry, when stationary saws 

are placed inside ventilated enclosures, 

and the set-up permits the operator to 

stand outside the enclosure. A 78- 

percent reduction in respirable quartz 

exposure was observed (from 354 mg/m3

to 78 mg/m3) when workers used a sitebuilt ventilated booth outdoors as 

opposed to cutting with no booth (ERG– 

C, 2008). 

Ventilation. Ventilation is another 

engineering control method used to 

minimize airborne concentrations of a 

contaminant by supplying or exhausting 

air. Two types of systems are commonly 

used: LEV and dilution ventilation. LEV 

is used to remove an air contaminant by 

capturing it at or near the source of 

emission, before the contaminant 

spreads throughout the workplace. 

Dilution ventilation allows the 

contaminant to spread over the work 

area but dilutes it by circulating large 

quantities of air into and out of the area. 

Consistent with past recommendations 

such as those included in the 

Hexavalent Chromium Rule, OSHA 

prefers the use of LEV systems to 

control airborne toxics because, if 

designed properly, they efficiently 

remove contaminants and provide for 

cleaner and safer work environments. 

The use of effective exhaust 

ventilation in controlling worker 

exposures to crystalline silica can be 

illustrated by an example in the mineral 

processing industry. Here, the highest 

exposure levels obtained by OSHA were 

associated with bag dumping and 

disposal operations at a pottery clay 

manufacturing company (OSHA SEP 

Inspection Report 116178096). After the 

facility installed ventilated bag disposal 

hoppers, HEPA filters, and an enhanced 

LEV system, the exposure of the 

production workers was reduced by 

about 80 percent (from 221 mg/m3 to 44 

mg/m3). A Canadian study of a rockcrushing plant also shows the 

effectiveness of LEV systems (Grenier, 

1987); the plant, originally equipped 

with a general exhaust ventilation 

system with fabric dust collectors, 

processed rock containing as much as 

60 percent crystalline silica. Operation 

of the LEV system was associated with 

reductions of respirable crystalline 

silica levels ranging from 20 to 79 

percent. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56455 

LEV can be adapted to diverse sources 

of emissions. For workers who empty 

bags or mix powders that contain 

crystalline silica material, a portable 

exhaust trunk positioned near the bagdumping hopper can capture a portion 

of the dust released during that activity. 

Additional crystalline silica exposure 

can occur when workers compress 

empty bags, an activity that can also be 

performed with LEV control (PEA, 

Chapter 4). 

LEV can also be applied to operations 

involving portable tools. The benefits of 

tool-mounted LEV systems for 

controlling crystalline silica have been 

demonstrated by two NIOSH 

evaluations. In one evaluation, NIOSH 

tested two tool-mounted LEV shrouds 

for hand-held pneumatic chipping 

equipment (impact drills): one custom 

built, the other a commercially available 

model. Comparing multiple short-term 

exposure samples, NIOSH found that 

the shrouds reduced personal breathing 

zone (PBZ) respirable dust by 48 to 60 

percent (NIOSH, 2003–EPHB 282–11a). 

In a separate evaluation, NIOSH 

collected short-term PBZ samples while 

workers used 25- or 30-pound 

jackhammers to chip concrete from 

inside concrete mixer truck drums. 

During 90- to 120-minute periods of 

active chipping, mean respirable silica 

levels decreased by 69 percent when the 

workers used a tool-mounted LEV 

shroud in these enclosed spaces 

(NIOSH, 2001–EPHB 247–19). 

In the railroad transportation 

industry, dust control kits that 

incorporate LEV are designed to reduce 

the amount of ballast dust released by 

activities of heavy equipment during 

maintenance. These kits can be used 

with brooming equipment (mechanical 

sweepers) and present an alternative to 

relying on cab modification. Workers 

that operate brooming equipment have 

the greatest potential for elevated 

exposures among workers in this 

industry, and the Agency believes that 

kits would be a better control measure 

than cab modification because they 

reduce exposures at the source. 

Unfortunately, information regarding 

the effectiveness of these kits in 

reducing worker exposure to crystalline 

silica is not available from the 

manufacturer. OSHA is therefore 

requesting any relevant information that 

would aid the Agency in determining 

the potential impact of dust control kits 

in the railroad transportation industry 

(HTT, 2003; ERG–GI, 2008). 

Based on the information presented in 

OSHA’s technological feasibility 

analysis, many exposures in the 

workplace have occurred, in part, due to 

faulty ventilation systems and improper 

work practices that minimize their 

efficiency. In many cases, exposures can 

be reduced with the proper use and 

maintenance of ventilation systems 

(PEA, Chapter 4). 

Dust suppression. Dust suppression 

methods are generally effective in 

controlling respirable crystalline silica 

dust, and they can be applied to many 

different operations such as material 

handling, rock crushing, abrasive 

blasting, and operation of heavy 

equipment (Smandych et al., 1998). 

Dust suppression can be accomplished 

by one of three systems: (1) wet dust 

suppression, in which a liquid or foam 

is applied to the surface of the dustgenerating material; (2) airborne 

capture, in which moisture is dispensed 

into a dust cloud, collides with 

particles, and causes them to drop from 

the air; and (3) stabilization, which 

holds down dust particles by physical 

or chemical means (lignosulfonate, 

calcium chloride, and magnesium 

chloride are examples of stabilizers). 

The most common dust suppression 

controls encountered during the 

technological feasibility review 

correspond to wet methods (PEA, 

Chapter 4). Water is generally an 

inexpensive and readily available 

resource and has been proven an 

efficient engineering control method to 

reduce exposures to airborne crystalline 

silica-containing dust. Dust, when wet, 

is less able to become or remain 

airborne. 

In its analysis of technological 

feasibility, OSHA demonstrated that wet 

methods are effective in a wide variety 

of operations. For example, respirable 

quartz exposures for masonry cutters 

using stationary saws were substantially 

lower when wet cutting was performed 

instead of dry cutting (mean levels of 42 

mg/m3 versus 345 mg/m3). Also, the 

exposure level for fabricators in the 

stone and stone products industry, who 

produce finished stone products from 

slabs, can be reduced substantially by 

applying wet method controls. Simcox 

et al. (1999) shows that exposures of 

fabricators at granite-handling facilities 

were reduced by 88 percent (490 mg/m3

to 60 mg/m3) when all dry-grinding tools 

used on granite were either replaced or 

modified to be water-fed. 

Regarding the application of wet 

methods to operations involving 

portable equipment, recent studies show 

that using wet methods to control 

respirable dust released during chipping 

with hand-held equipment can reduce 

worker exposure substantially. NIOSH 

(2003–EPHB 282–11a) investigated a 

water-spray dust control used by 

construction workers breaking concrete 

with 60- and 90-pound jackhammers. A 

spray nozzle was fitted to the body of 

the chipping tool, and a fine mist was 

directed at the breaking point. 

Compared with uncontrolled pavement 

breaking, PBZ respirable dust 

concentrations were between 72 and 90 

percent lower when the water spray was 

used. Williams and Sam (1999) also 

reported that a water-spray nozzle 

mounted on a hand-held pneumatic 

chipper decreased respirable dust by 

approximately 70 percent in the 

worker’s breathing zone. 

Washing aggregate also reduces the 

amount of fine particulate matter 

generated during subsequent use or 

handling. Burgess (1995) reports that the 

use of washed sand, from which a 

substantial portion of the fine particles 

have been removed, results in respirable 

crystalline silica exposures that are 

generally lower than when sand is not 

pre-washed. Plinke et al. (1992) also 

report that increasing moisture content 

decreases the amount of dust generated 

and state that it is often most efficient 

to apply water sprays to material before 

it reaches a transfer point so that the 

dust has time to absorb water before 

being disturbed. 

For the railroad transportation 

industry, OSHA is recommending that 

ballast be washed before it is loaded 

into hopper cars. Ballast wetted at the 

supplier’s site might dry prior to 

reaching the dumping site (NIOSH 

HETA–92–0311, 2001). In this 

circumstance, applying an additional 

layer of blanketing foam or other sealing 

chemical suppressant on top of the rail 

car can reduce water evaporation and 

provide an additional type of dust 

suppression (ECS, 2007). Work practice 

controls. Work practice controls 

systematically modify how workers 

perform an operation, and often involve 

workers’ use of engineering controls. 

For crystalline silica exposures, OSHA’s 

technological feasibility analysis shows 

that work practice controls are generally 

applied complementary to engineering 

controls, to adjust the way a task is 

performed. For work practice controls to 

be most effective, it is essential that 

workers and supervisors are fully aware 

of the exposures generated by relevant 

workplace activities and the impact of 

the engineering controls installed. Work 

practice controls are preferred over the 

use of personal protective equipment 

since work practice controls can address 

the exposure of silica at the source of 

emissions, thus protecting nearby 

workers. 

Work practice controls can enhance 

the effects of engineering controls. For 

example, to ensure that LEV is working 

effectively, a worker would position it 

so that it captures the full range of dust 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56456 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

created, thus minimizing silica 

exposures. 

A good example of adequate work 

practice controls can be found in readymixed concrete operations. Exposure 

data available to OSHA indicate that all 

truck drivers or other workers who 

remove residual concrete inside readymixed truck mixer drums have silica 

exposures greater than the proposed 

PEL, with some exposures approaching 

10,000 mg/m3. The Agency recommends 

wet methods and ventilation as 

appropriate engineering controls and 

also gives priority to performing a 

particular work practice that can reduce 

exposures. Specifically, this work 

practice involves the timely rinsing of 

drum mixers. One report (Williams and 

Sam, 1999) concluded that heavy buildup of concrete inside truck mixer drums 

results in higher concentrations of 

worker exposure to crystalline silica 

during cleaning because a greater 

amount of time is required to remove 

the build-up. Rinsing the drum with 

water immediately after each load helps 

minimize build-up and the resulting 

dust exposure. The same cleaning 

methods are used, such as water 

pressure and scraping, independently of 

how often rinsing is performed. 

However, by rinsing the tanks with 

more frequency, the employer is 

modifying the nature of the cleaning 

operation because less concrete will be 

present, and thus less respirable dust 

created, during each cleaning. 

Another example of good work 

practices can be observed in the 

porcelain enameling industry. One 

facility stated that porcelain applicators 

can ensure that they are making optimal 

use of LEV by avoiding positioning 

themselves between the enamel spray 

and the ventilation system. For large 

items, workers can use a turntable 

support to rotate the item so that it can 

be sprayed on all sides while the worker 

maintains the spray direction pointing 

into the ventilated booth (Porcelain 

Industries, 2004a). 

Combined control methods. Exposure 

documentation obtained by the Agency 

demonstrates that for many operations, 

a combination of engineering and work 

practice controls reduces silica exposure 

levels more effectively than a single 

control method. The following examples 

represent preliminary feasibility 

conclusions for several industries. 

In the dental equipment and supplies 

industry, OSHA has found that 

employers can limit the exposure of 

most workers to 50 mg/m3 or less by 

implementing a combination of 

engineering controls, including 

improving ventilation systems (at bagdumping stations, weighing and mixing 

equipment, and packaging machinery) 

and designing workstations to minimize 

spills, and encouraging work practices 

that maximize the effect of engineering 

controls. One facility that implemented 

these controls reduced median exposure 

levels by 80 percent, from 160 mg/m3 to 

32 mg/m3 (OSHA SEP Inspection Report 

122252281). 

Based on the exposure profile for the 

rock and concrete drilling industry, 

construction sites have already achieved 

compliance with the proposed PEL for 

about half of the workers operating 

drilling rigs through a combination of 

controls, including wet dust 

suppression methods, shrouds, and 

hoods connected to dust extraction 

equipment, and management of dust 

collection dump points (PEA, Chapter 

4). 

An example from a routine cupola 

relining in the ferrous foundry industry 

also demonstrates the benefit of a 

combination of controls. Samples taken 

before and after additional controls were 

installed reflect a 90-percent reduction 

of the median worker exposures (OSHA 

SEP Inspection Report 122209679). The 

modifications included using refractory 

material with reduced silica and greater 

moisture content, improving equipment 

and materials to reduce malfunction and 

task duration, wetting refractory 

material before removal, and assigning a 

consistent team of trained workers to 

the task. 

Burmeister (2001) also reported on the 

benefits of multiple controls on another 

refractory relining activity. Initially, a 

full-shift crystalline silica result of 2.74 

times the current calculated PEL was 

obtained while a worker chipped away 

the old refractory lining and then mixed 

the replacement refractory material. The 

foundry responded by holding a training 

meeting and seeking worker input on 

abatement actions, implementing a 

water control system to reduce dust 

generated during the pneumatic 

chipping process, purchasing chisel 

retainers that eliminated the need for 

workers to reach into the ladle during 

chipping, and purchasing a vacuum to 

remove dust and chipped material from 

the ladle. With these changes in place, 

a consultant found that exposure was 

reduced to 87 percent of the calculated 

PEL, representing a 70-percent 

reduction in worker exposure. 

These examples illustrate the 

importance and value of maintaining an 

effective set of engineering controls 

alongside work practice controls to 

optimize silica exposure reduction. The 

proposed requirements are consistent 

with ASTM E 1132–06 and ASTM E 

2625–09, the national consensus 

standards for controlling occupational 

exposure to respirable crystalline silica 

in general industry and in construction, 

respectively. Each of these standards 

has explicit requirements for methods of 

compliance. These requirements 

include use of properly designed 

engineering controls such as ventilation 

or other dust suppression methods and 

enclosed workstations such as control 

booths and equipment cabs; 

requirements for maintenance and 

evaluation of engineering controls; and 

implementation of certain work 

practices such as not working in areas 

where visible dust is generated from 

respirable crystalline silica containing 

materials without use of respiratory 

protection. OSHA has elected to 

propose a performance standard for 

general industry in which particular 

engineering and work practice controls 

are not specified. Instead, the standard 

requires that employers use engineering 

and work practice controls to achieve 

the PEL. In this case the use of properly 

designed, maintained, and regularly 

inspected engineering controls is 

implied by the ongoing ability of the 

employer to achieve the PEL. The 

national consensus standard for 

construction (ASTM E 2625–09) 

includes task-based control strategies for 

situations where exposures are known 

from empirical data. This approach is 

consistent with the alternative approach 

for construction operations in paragraph 

(f)(2) described below. 

Paragraph (f)(2) of the proposed rule 

provides an alternative approach to 

achieve compliance with paragraph (f), 

Methods of Compliance, for 

construction operations. Under this 

paragraph, employers that implement 

the specific engineering controls, work 

practices, and, if required, respiratory 

protection described in Table 1 (please 

refer to paragraph (f) of the proposed 

rule) are considered to be in compliance 

with the requirements for engineering 

and work practice controls in paragraph 

(f)(1) of the proposed rule. An advantage 

of complying with Table 1 is that the 

employer need not make a 

determination of the hierarchy of 

controls, because the table incorporates 

that determination for each job 

operation listed. Furthermore, proposed 

paragraph (d)(8)(i) specifies that if an 

employer chooses to follow Table 1, the 

employer need not conduct exposure 

assessments required by paragraph (d) 

of the proposed rule. Rather, for those 

operations in Table 1 where respirator 

use is required, proposed paragraph 

(d)(8)(ii) requires employers to presume 

that workers engaged in those 

operations are exposed above the PEL; 

in those cases, the employer would be 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56457 

required to comply with all provisions 

of the standard that apply to exposures 

above the PEL except for monitoring. 

For instance, when Table 1 requires 

workers to use respirators, the employer 

relying on Table 1 must: establish a 

regulated area or access control plan 

pursuant to proposed paragraph (e); 

comply with the cleaning methods 

provisions in proposed paragraph (f)(4); 

comply with the prohibition of 

employee rotation as specified in 

proposed paragraph (f)(5); establish a 

respiratory protection program pursuant 

to proposed paragraph (g)(2); and 

provide medical surveillance pursuant 

to paragraph (h) if workers are exposed 

for 30 or more days per year. 

Table 1 was developed using 

recommendations made by small entity 

representatives through the Small 

Business Regulatory Enforcement 

Fairness Act (SBREFA) process. The 

SBREFA panel asked OSHA to develop 

a provision that detailed what specific 

controls to use for each construction 

operation covered by the rule in order 

to achieve compliance with paragraph 

(f)(1). Additionally, the Advisory 

Committee for Construction Safety and 

Health (ACCSH) has recommended that 

OSHA proceed with the development of 

Table 1. The table provides a list of 13 

construction operations that expose 

workers to respirable crystalline silica 

as well as control strategies (engineering 

controls, work practices, and 

respirators) that reduce those exposures. 

In developing control strategies for 

each of the 13 construction operations 

in Table 1, OSHA relied upon 

information from a variety of sources 

including scientific literature, NIOSH 

reports, OSHA site visits, and 

compliance case files (SEP reports). For 

several of the listed operations and 

controls, the Agency requests additional 

information from the public that will 

allow the Agency to determine whether 

the operations, corresponding control 

strategies, and conditions of use should 

be modified or removed from Table 1. 

OSHA also requests comment on the 

degree of specificity used for 

engineering and work practice controls 

for tasks identified in Table 1, including 

maintenance requirements. 

Table 1 implements a novel approach 

for OSHA. The Agency believes that the 

table will provide significant benefits to 

workers and employers by ensuring that 

workers are adequately protected, 

providing specific approaches for 

complying with paragraph (f) 

requirements, and reducing the 

monitoring and sampling burden. 

The table divides operations 

according to duration into ‘‘less than or 

equal to’’ four-hours-per-day tasks and 

‘‘greater than’’ four-hours-per-day tasks. 

The Agency recognizes that some 

activities do not last a full work shift, 

and often some activities are performed 

for half-shifts or less. The duration of a 

task influences the extent of worker 

exposure and the selection of 

appropriate control strategies. OSHA 

followed its hierarchy of controls to 

develop these control strategies. 

Respiratory protection has been 

included in Table 1 for operations in 

which the specified engineering and 

work practice controls may not maintain 

worker exposures at or below the 

proposed PEL for all workers and at all 

times. Employers who comply with 

Table 1 need not assess employee 

exposures as otherwise required under 

paragraph (f), and workers in these 

circumstances will not have the benefit 

of conventional exposure data to 

characterize their exposures. Because, in 

the absence of an exposure assessment, 

employers will not be able to confirm 

that exposures are below the PEL, or 

identify circumstances in which 

exposures may exceed the PEL, the 

Agency is proposing to require 

respiratory protection in situations 

where overexposures may occur even 

with the implementation of engineering 

and work practice controls. The Agency 

is requesting comments regarding the 

appropriateness of the use and selection 

of respirators in several operations. 

If an employer anticipates that a 

worker will perform a single operation 

listed in Table 1 for four hours or less 

during a single shift, then the employer 

must ensure that the worker uses 

whichever respirator is specified in the 

‘‘≤4 hr/day’’ column in the table. For 

example, if an employer anticipates that 

a worker will operate a stationary 

masonry saw for four hours or less, and 

the worker does not perform any other 

operation listed in Table 1, the worker 

would not be required to use respiratory 

protection because there is no respirator 

requirement for that entry in the table. 

If an employer anticipates that a 

worker will perform a single operation 

listed in Table 1 for more than four 

hours, then the employer must ensure 

that the worker uses the respirator 

specified in the ‘‘>4 hr/day’’ column in 

Table 1 for the entire duration of the 

operation. For example, if an employer 

anticipates that a worker will operate a 

stationary masonry saw for more than 

four hours, and the worker does not 

perform any other operation listed in 

Table 1, the worker would be required 

to wear a half-mask respirator for the 

entire duration of the operation (refer to 

Table 1). 

Additionally, for workers who engage 

in two or more discrete operations from 

Table 1 for a total of more than four 

hours during a single work shift, 

employers that rely on Table 1 must 

provide, for the entire duration of each 

operation performed, the respirator 

specified in the ‘‘>4 hr/day’’ column for 

that operation, even if the duration of 

that operation is less than four hours. If 

no respirator is specified for an 

operation in the ‘‘>4 hr/day’’ column, 

then respirator use would not be 

required for that part of a worker’s shift. 

For example, if a worker is using a 

stationary masonry saw for three hours 

and engages in tuckpointing for two 

hours in the same the shift, the 

employer would be required to ensure 

that the worker uses a half-mask 

respirator for the three hours engaged in 

sawing, and a tight-fitting, full-face 

PAPR for the two hours engaged in 

tuckpointing work. In other words, if a 

worker uses a stationary saw and 

engages in a tuckpointing operation for 

a total of more than four hours in a 

single work shift, the worker would be 

required to use a half-mask respirator 

for the entire time he or she operates the 

stationary saw and a tight-fitting, fullface PAPR for the tuckpointing work, 

regardless of how long each task is 

performed. 

The following paragraphs describe the 

engineering controls, work practices and 

respirators selected for each of the 

operations listed in Table 1. In addition, 

the Agency describes the information 

that it has relied upon to develop the 

control strategies. 

For most control strategies in the 

table, OSHA is proposing to require 

additional specifications to ensure that 

the strategies are effective. The most 

frequently required additional 

specifications are: 

• Changing water frequently when 

using water delivery systems, to avoid 

silt build-up in the water and prevent 

wet slurry from accumulating and 

drying. This prevents silica from 

becoming airborne when the water 

becomes aerosolized by the rotation of 

equipment or when the water dries and 

leaves residual respirable silicacontaining dust. 

• Operating equipment such that no 

visible dust is emitted from the process. 

Visible dust may be an indication that 

the controls are not operating 

effectively. The absence of visible dust 

does not necessarily indicate that 

workers are protected, but visible dust 

is a clear indication of a potential 

problem. 

• Providing sufficient ventilation to 

prevent build-up of visible airborne dust 

when working indoors or in enclosed 

spaces. Stagnant air in an enclosed 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56458 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

environment may increase worker 

exposures. 

• Ensuring that saw blades and 

abrasive discs are not excessively worn. 

Excessive wear tends to increase 

respirable silica emissions and worker 

exposures. 

• Using dust collectors according to 

manufacturers’ specifications. 

Manufacturer specifications are often 

based on operation-specific designs. 

Use of stationary masonry saws. For 

workers operating stationary masonry 

saws, OSHA is proposing to require that 

the saws be equipped with an integrated 

water delivery system that is operated 

and maintained to minimize dust 

emissions. The exposure profile created 

for this operation shows that cutting 

with wet methods offers a clear 

reduction to exposures, as opposed to 

dry cutting with no controls or with a 

mix of administrative or other 

engineering controls. The Agency 

obtained 12 samples for workers dry 

cutting with no engineering controls, 9 

samples for workers dry cutting with a 

mix of controls, and 7 samples for 

workers operating the saws with water 

at the point of operation. The mean, 

median, and range values were all lower 

for workers using wet methods: 

• Median of 33 mg/m3 (a 34-percent 

reduction from dry cutting and 63- 

percent reduction from dry cutting with 

some controls). 

• Mean of 42 mg/m3 (an 88-percent 

reduction from dry cutting and 80- 

percent reduction from dry cutting with 

some controls). 

• A maximum value of 93 mg/m3, as 

opposed to a maximum value of 2,005 

mg/m3 for dry cutting, and 824 mg/m3 for 

dry cutting with some controls. 

The Agency concludes, based on this 

information and the analysis discussed 

in the exposure profile for this operation 

(PEA, Chapter 4), that the water delivery 

system specified in Table 1 consistently 

reduces worker exposures to or below 

the proposed PEL when the saws are 

used for four hours or less. As a result, 

respiratory protection is not included in 

the control strategy for these operations. 

OSHA believes that, even when workers 

operate stationary masonry saws for 

eight hours, wet methods will reduce 8- 

hour exposures to or below the 

proposed PEL most of time, as described 

in Chapter 4 of the PEA. However, the 

maximum TWA value measured for a 

stationary masonry saw operator is 93 

mg/m3, equivalent to a 4-hr exposure of 

47 mg/m3 (see Chapter 4 of the PEA). 

Thus, when workers perform this 

operation for more than four hours, 

silica exposures may occasionally 

exceed the PEL. Because, in the absence 

of an exposure assessment, employers 

will not be able to confirm that 

exposures are below the PEL, or identify 

circumstances in which exposures may 

exceed the PEL, the proposed rule 

requires that employers provide halfmask respirators to workers who use 

stationary masonry saws for more than 

four hours. 

Use of hand-operated grinders. The 

table provides employers with two 

different control strategies. 

Option 1: Use water-fed grinders that 

continuously feed water to the cutting 

surface, operated and maintained to 

minimize dust emissions. For 

operations lasting less than four hours, 

OSHA is proposing that respirators will 

not be required. For operations lasting 

four hours or more, OSHA is proposing 

the use of half-mask respirators to 

ensure workers are protected. 

For its technological feasibility 

analysis, OSHA did not obtain any 

sample results where wet grinding 

occurred. Information available to the 

Agency suggests that overexposures still 

occur when using wet methods and that 

there are additional challenges such as 

limited applications. OSHA has decided 

to include this control strategy based on 

the use of water systems on similar tools 

used in the cut stone and stone products 

manufacturing industry that have 

shown a reduction of exposures to well 

below 100 mg/m3 (OSHA 3362–05). The 

Agency believes that similar reductions 

can be achieved for grinding operations 

because the amount of respirable dust 

produced in these operations is 

comparable. Based on this inference, 

OSHA believes that wet methods alone 

will provide sufficient protection for 

shifts lasting four hours or less, and is 

proposing to require the use of halfmask respirators with an APF of 10 for 

shifts lasting more than four hours. 

The Agency requests comments and 

additional information regarding wet 

grinding and the adequacy of this 

control strategy. 

Option 2: Use hand-operated grinders 

with commercially available shrouds 

and dust collection systems operated 

and maintained to minimize dust 

emission. The dust collector must be 

equipped with a HEPA filter and must 

operate at 25 cubic feet per minute (cfm) 

or greater airflow per inch of blade 

diameter. OSHA is proposing to require 

the use of half-mask respirators at all 

times, for outdoor and indoor operations 

alike, to ensure workers are protected. 

OSHA’s exposure profile for this 

operation contains 13 samples 

associated with the use of LEV. Two of 

these samples are associated with 

outdoor activities (40 mg/m3 and 53 mg/ 

m3), and 11 samples are associated with 

indoor work (a range of 12 mg/m3 to 208 

mg/m3). Overall, exposure samples show 

that outdoor exposures are lower than 

indoor exposures. The mean, median, 

and range values for these operations 

are: 

• Median of 47 mg/m3 for outdoor 

operations with LEV, and 107 mg/m3 for 

indoor operations with LEV. 

• Mean of 46 mg/m3 for outdoor 

operations with LEV, and 96 mg/m3 for 

indoor operations with LEV. 

• A maximum value of 53 mg/m3 for 

outdoor operations with LEV, and 208 

mg/m3 for indoor operations with LEV. 

These values suggest that workers 

would sometimes achieve levels below 

the proposed PEL with LEV. However, 

the Agency recognizes that elevated 

exposures occur even with the use of 

LEV in these operations based on the 

fact that 8 out of 13 samples collected 

exceed the proposed PEL, with 6 

samples ranging from 100 mg/m3 to 250 

mg/m3. Based on this information, 

OSHA is proposing that employers 

apply the engineering control specified 

and equip workers with half-mask 

respirators at all times. It is important to 

note that OSHA has preliminarily 

concluded that the LEV control outlined 

in the table will not reduce and 

maintain exposures to the proposed PEL 

for all workers. However, these controls 

will reduce exposures within the APF of 

10 offered by half-mask respirators. The 

Agency seeks additional information to 

confirm that the control strategy 

(including the use of half-mask 

respirators) listed in the table will 

reduce workers’ exposure to or below 

the PEL. 

Tuckpointing. OSHA is proposing to 

require employers to equip grinding 

tools with commercially available 

shrouds and dust collection systems, 

operated and maintained to minimize 

dust emissions. The grinder must be 

operated flush against the working 

surface, with grinding operations 

performed against the natural rotation of 

the blade (i.e., mortar debris must be 

directed into the exhaust). Employers 

would be required to use vacuums that 

provide at least 80 cubic feet per minute 

(cfm) to 85 cfm airflow through the 

shroud and include filters that are at 

least 99 percent efficient. 

Recent dust control efforts for 

tuckpointing have focused on using a 

dust collection hood, or shroud, which 

encloses most of the grinding blade. It 

is used with a vacuum cleaner system 

that exhausts air from these hood 

systems and collects dust and debris. 

These shroud and vacuum combinations 

capture substantial amounts of debris, 

but air monitoring results summarized 

in OSHA’s exposure profile for this 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56459 

operation show that even with this 

control in place, silica exposures often 

continue to exceed 100 mg/m3, with 

many of the results exceeding 250 mg/

m3. 

The highest exposure obtained for 

outdoor work with LEV (6,196 mg/m3), 

and many other exposures, suggest that 

there are circumstances in which the 

protection factor offered by a PAPR will 

be needed to reduce worker exposure to 

below 50 mg/m3. OSHA is aware that 

some exposures may be effectively 

controlled with the LEV system and a 

respirator with an APF of 10, but is 

proposing to require the use of the LEV 

system with respirators that provide an 

APF of 50 to ensure that the control 

strategy protects those workers with 

extremely elevated exposures. Based on 

this information, OSHA estimates that a 

substantial percentage of the worker 

population will need respiratory 

protection in the form of a powered airpurifying respirator (PAPR) with a 

loose-fitting helmet or a negativepressure full-facepiece respirator 

regardless of task duration. 

Furthermore, OSHA is stressing the 

importance of sufficient air circulation 

in enclosed or indoor environments to 

maximize the effect of the control 

strategy outlined. Elevated results are 

reported for tuckpointers in operations 

performed in areas with limited air 

circulation (including indoors). As such, 

the Agency is proposing to require 

employers to provide for ventilation to 

prevent the accumulation of airborne 

dust during operations performed in 

enclosed spaces, in addition to requiring 

equipment to be operated so that no 

visible dust is emitted from the process. 

Use of jackhammers and other impact 

drillers. The table provides employers 

with two different control strategies. 

Option 1: Apply a continuous stream 

or spray of water at the point of 

operation. 

Results in OSHA’s exposure profile 

show that the wet methods attempted in 

the five samples obtained were not 

effective at all in reducing exposures; in 

fact, the statistical values are higher 

than those under baseline conditions. 

Based on the best available information, 

OSHA believes that no single wet 

method was applied effectively and 

consistently throughout these 

operations, and the data obtained for 

wet methods is reflective of that 

inconsistency (ERG–C, 2008; PEA, 

Chapter 4). The three highest results for 

the samples corresponding to wet 

methods show respirable dust levels 

higher than the mean respirable dust 

value for comparable uncontrolled 

operations, indicating that the wet 

method control was not applied 

effectively, as it was not reducing total 

respirable dust levels. 

Conversely, however, OSHA has 

obtained information from individual 

employers, NIOSH, and an informal 

consortium of New Jersey organizations 

interested in controlling silica during 

road construction activities that have all 

tested wet dust suppression methods 

with chipping and breaking equipment. 

The results of these tests indicate that 

wet dust suppression is effective in 

reducing respirable crystalline silica 

exposures. 

The Agency obtained a reading for a 

jackhammer operator breaking concrete 

outdoors, where a continuous stream of 

water was directed at the breaking 

point. When compared with the median 

value in the exposure profile for outdoor 

and uncontrolled operations, the result 

represents a 77-percent exposure 

reduction in respirable quartz (OSHA 

SEP Inspection Report 106719750). 

NIOSH provided similar findings 

when it completed several studies 

evaluating water spray devices to 

suppress dust created while workers 

used chipping and breaking equipment. 

Compared with concentrations during 

uncontrolled pavement breaking, 

respirable dust results were between 72 

and 90 percent lower when the water 

spray was used (NIOSH EPHB–282–11a, 

2003). A follow-up NIOSH study 

reported a similar 77-percent reduction 

in silica concentration during 60-minute 

trials with a solid cone nozzle 

producing water mist (NIOSH EPHB– 

282–11c–2, 2004). 

Two other findings also show that 

water spray systems are effective in 

reducing respirable dust concentrations. 

Williams and Sam (1999) evaluated a 

shop-built water spray system attached 

to a hand-held pneumatic chipper used 

by a worker removing hardened 

concrete from inside a mixing truck 

drum. Although this task is not typically 

performed by construction workers, it 

represents a worst-case environment (in 

a confined space or indoors) for 

construction concrete chipping and 

breaking jobs. Water spray decreased 

respirable dust by about 70 percent in 

the worker’s breathing zone, again 

showing that a water spray system offers 

substantial reduction in silicacontaining dust generated. 

Additionally, the New Jersey Laborers 

Health and Safety Fund, NIOSH, and 

the New Jersey Department of Health 

and Senior Services have collaborated 

in publishing simple instructions for 

developing spray equipment for 

jackhammers. A design tested in New 

Jersey involving a double water spray— 

one on each side of the breaker blade— 

reduced peak dust concentrations by 

approximately 90 percent compared 

with the peak concentration measured 

for uncontrolled breaking (Hoffer, 2007; 

NIOSH 2008–127, 2008; NJDHSS, no 

date). 

OSHA believes that, even when 

workers perform impact drilling for 

eight hours, wet methods will reduce 

TWA exposures to or below the 

proposed PEL most of time, as described 

in Chapter 4 of the PEA. However, when 

workers perform this operation for more 

than four hours, silica exposures may 

occasionally exceed the PEL. Because, 

in the absence of an exposure 

assessment, employers will not be able 

to confirm that exposures are below the 

PEL, or identify circumstances in which 

exposures may exceed the PEL, the 

proposed rule requires that employers 

provide respiratory protection to 

workers who perform impact drilling for 

more than four hours. 

OSHA notes that applying the lowest 

exposure reduction of the values 

reported in the studies would reduce 

the highest range of exposures to within 

an APF of 10 provided by a half-mask 

respirator and, thus, consistently and 

adequately protect workers for a full 

shift. Additionally, for impact drilling 

operations lasting four hours or less, 

OSHA is proposing to allow workers to 

use water delivery systems without the 

use of respiratory protection, as the 

Agency believes that this dust 

suppression method alone will provide 

consistent, sufficient protection. OSHA 

is requesting comments and additional 

information that address the 

appropriateness of this control strategy. 

It is important to mention that the 

highest exposures in the profile were 

obtained during indoor work, with a 

maximum value of 3,059 mg/m3. OSHA 

believes that these elevated results are 

in part due to poor air circulation in 

enclosed environments. The Agency 

believes that it is particularly important 

to ensure adequate air circulation 

during indoor work, so that airborne 

dust does not accumulate and 

contribute to higher exposures. As such, 

the proposed Table 1 includes a 

specification that directs employers to 

provide adequate ventilation during 

indoor work so as to prevent build-up 

of visible airborne dust. 

Option 2: Use tool-mounted shroud 

and HEPA-filtered dust collection 

system, operated and maintained to 

minimize dust emissions. 

Based on available information, LEV 

systems are also able to effectively 

reduce respirable airborne silica dust. 

NIOSH tested two tool-mounted LEV 

shrouds during work with chipping 

hammers intended for chipping vertical 

concrete surfaces. Comparing multiple 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56460 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

short–term samples, NIOSH found that 

the shrouds reduced respirable dust by 

48 to 60 percent (Echt et al., 2003; 

NIOSH EPHB 282–11a, 2003). In a 

separate evaluation, NIOSH showed that 

this type of LEV system controls dust 

equally well for smaller chipping 

equipment. Mean silica levels decreased 

69 percent when the workers used a 

tool-mounted LEV shroud in enclosed 

spaces (NIOSH EPHB 247–19, 2001). In 

this study, a combination of LEV and 

general exhaust ventilation provided 

additional dust control, resulting in a 78 

percent decrease in silica readings. This 

finding further supports OSHA’s 

proposal to ensure that additional 

ventilation is provided during indoor 

work to prevent the accumulation of 

airborne dust. 

OSHA believes that, even when 

workers perform impact drilling for 

eight hours, these controls will reduce 

TWA exposures to or below the 

proposed PEL most of time, as described 

in Chapter 4 of the PEA. However, when 

workers perform this operation for more 

than four hours, silica exposures may 

occasionally exceed the PEL. Because, 

in the absence of an exposure 

assessment, employers will not be able 

to confirm that exposures are below the 

PEL, or identify circumstances in which 

exposures may exceed the PEL, the 

proposed rule requires that employers 

provide respiratory protection to 

workers who perform impact drilling for 

more than four hours. OSHA believes 

that that LEV systems will reduce the 

highest range of airborne respirable 

silica concentrations (in the exposure 

profile) to within an APF provided by 

a half-mask respirator for operations 

lasting a full shift. For operations lasting 

four hours or less, OSHA is proposing 

to allow workers to use the shroud and 

HEPA vacuum system without 

respirators, as the Agency believes that 

this control alone will provide 

consistent, sufficient protection. The 

highest exposure values were obtained 

during indoor work, and the Agency is 

proposing that employers provide 

appropriate air circulation in order to 

maximize the effectiveness of the 

proposed control strategy. 

Use of rotary hammers or drills 

(except overhead use). Table 1 requires 

that drills be equipped with a hood or 

cowl and a HEPA-filtered dust collector, 

operated and maintained to minimize 

dust emissions. The proposed control 

strategy also directs employers to 

eliminate blowing or dry sweeping 

drilling debris from working surfaces. 

Of the 14 respirable quartz readings 

summarized in the exposure profile for 

this operation, seven represent hole 

drilling indoors under uncontrolled 

conditions. The highest reading 

obtained for workers in this job 

category, 286 mg/m3, was recorded for a 

worker drilling holes with a 3⁄4-inch bit 

in the floor of a concrete parking garage 

where air circulation was poor (Lofgren, 

1993). The other seven results, most of 

which were collected during outdoor 

drilling of brick and rock, are also 

spread over a wide range but tend to be 

lower than (less than half) the indoor 

values, with a maximum of 130 mg/m3

(NIOSH HETA–2003–0275–2926). 

Shepherd et al. (2009) found that 

compared with uncontrolled drilling, 

using dust collection cowls connected 

to portable vacuums reduced silica 

exposures by 91 to 98 percent. The 

researchers tested four commercially 

available combinations of two cowls 

and two vacuums indoors. Although 

investigators note that results might 

vary for different drill types and drill bit 

sizes, OSHA estimates that the proposed 

control strategy will consistently 

maintain exposures below the proposed 

PEL even during periods of intense 

drilling. OSHA is proposing that 

employers ensure that dust collectors 

are used according to manufacturer’s 

specifications in order to maximize dust 

reduction, and that the vacuums used 

are appropriate for the nature of the task 

to provide the adequate suction rate. 

Based on the percent reductions 

documented in the Shepherd study, 

using a drill equipped with a hood or 

cowl and a HEPA-filtered dust collector 

reduces the highest exposure reading in 

the profile to levels below the proposed 

PEL. As such, OSHA anticipates that 

this control strategy alone will reduce or 

maintain exposures below 50 mg/m3 for 

workers using rotary hammers or drills 

for durations up to 8 hours (excluding 

overhead work). 

Hallin (1983) indicates a greater 

potential for overexposure during 

overhead drilling. A test run reported 

that drilling for 120 minutes into a 

concrete ceiling with a percussion drill 

and a hammer drill gave respirable 

quartz concentrations of 1,740 mg/m3

and 720 mg/m3, respectively. The 

percussion drill was later fitted with a 

dust collector, and a 180-minute test run 

produced a value of 80 mg/m3. This type 

of drilling was not addressed in the 

Shepherd report; therefore, OSHA 

cannot confirm that using the cowl and 

dust collector would sufficiently protect 

workers. The Agency has no additional 

information that would indicate that 

exposures resulting from overhead work 

might be consistently reduced below the 

proposed PEL. Based on these factors, 

OSHA is proposing to exclude this 

particular task from Table 1. 

Furthermore, the Agency concurs with 

the recommendation made by Hallin 

(1983) that overhead drilling is 

ergonomically stressful and should not 

be performed consistently for a full 

shift. 

Use of vehicle-mounted earth-drilling 

rigs for rock and concrete. Although the 

equipment used for each type of drilling 

varies, OSHA has addressed workers 

using drilling rigs of all types for rock, 

earth, and concrete together in the same 

section of the technological feasibility 

analysis. This is because the worker 

activities have much in common and 

the general methods of silica control are 

also similar. Specifically, these workers 

control the vehicle-mounted or rigbased drills from more than an arm’s 

length from the drill bit(s). They also 

perform certain intermittent tasks near 

the drilling point, such as fine-tuning 

the bit position, moving debris away 

from the drill hole, and working directly 

or indirectly with compressed air to 

blow debris from deep within the holes. 

When drilling rock, workers typically 

use rigs that are vertically oriented and 

equipped to produce a deep hole 

through the addition of bit extensions. 

This operation generally involves the 

drilling of one hole for an extended 

period of time, with minimal 

interruption. In contrast, when drilling 

concrete, workers often use rigs that 

consist of an array of one or many drills 

fixed to the maneuverable arm of a 

construction vehicle or purpose-built 

mobile machine, which permits the 

operator to produce a series of precisely 

spaced mid-size holes. This process 

requires operators to frequently start 

and stop the drilling process. 

Based on these differences, OSHA is 

proposing to require separate additional 

specifications for rock drilling and 

concrete drilling, with both types of 

drilling using LEV at the point of 

operation and water to suppress dust 

from the dust collector exhaust. The 

Agency estimates that these control 

strategies will protect workers from 

overexposures, as consistent use of dust 

extraction shrouds or hoods reduces 

worker exposures at both rock and 

concrete drilling sites. The control 

strategies for rock drilling and concrete 

drilling are discussed below. 

OHSA recognizes that enclosed cabs 

are available for concrete and rock 

drilling rigs, and operators who work in 

enclosed cabs will experience exposure 

reductions (ERG–C, 2008). OSHA is 

proposing that respirators will not be 

required for these operators, regardless 

of length of shift. Although cabs benefit 

operators while in the cab, they do not 

affect workers’ exposure during 

positioning or hole-tending activities. 

To effectively control exposures of all 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56461 

workers involved in the operation, 

employers must apply the engineering 

controls outlined in Table 1 to manage 

exposure sources. 

In order for the cabs to work 

optimally, OSHA is proposing that cabs 

have the following characteristics: (1) 

Air conditioning and positive pressure 

is maintained at all times, (2) incoming 

air is filtered through a pre-filter and a 

HEPA filter, (3) the cab interior is 

maintained as free as practicable from 

settled dust, and (4) door seals and 

closing mechanisms are working 

properly. Cecala et al. (2005) studied 

modifications designed to lower 

respirable dust levels in an enclosed cab 

on a 20-year-old surface drill at a silica 

sand operation. The study found that 

effective filtration and cab integrity (e.g., 

new gaskets, sealed cracks to maintain 

a positive-pressure environment) are the 

two key components necessary for dust 

control in an enclosed cab. OSHA 

believes that the cab specifications 

outlined will promote proper air 

filtration and cab integrity. Rock 

drilling. The control strategy for this 

operation specifies the use of a dust 

collection system around the drill bits 

as well as a water spray to wet the 

exhaust, operated and maintained to 

minimize dust emissions. Respiratory 

protection will not be required unless 

work is being performed under the 

shroud at the point of operation. 

Modern shroud designs, which are 

commercially available, have been 

shown to consistently achieve respirable 

dust reductions (Reed et al., 2008; 

Drilling Rig Manufacturer A, 2009). 

Moreover, NIOSH has quantified 

reductions in dust emissions associated 

with LEV used with a dowel drilling 

machine. For these concrete drilling 

rigs, NIOSH found that close-capture 

dust collection hoods reduced 

respirable dust concentrations by 89 

percent compared with drilling without 

the hoods. OSHA believes that similar 

reductions are achievable on rock 

drilling machines equipped with dust 

collection systems, as the quantity of 

airborne dust generated is comparable 

for both types of drilling. 

Additionally, OSHA believes it is 

important for employers to use dust 

collectors in accordance with 

manufacturer specifications. NIOSH has 

shown that dust collector efficiency is 

improved when workers use an 

appropriate suction rate, maintain the 

shroud in good condition, and keep the 

shroud positioned to fully enclose the 

bit as it enters the hole. The Agency is 

also proposing to include a visible dust 

specification, which employers can use 

as a tool to identify potential problems 

with controls. 

Due to the nature of rock drilling, 

workers often have to work under the 

shroud to clear tailings and dust from in 

or around the hole. When this work is 

performed, workers do not receive the 

same amount of protection from the 

control system, and they have to work 

closer to the point of dust generation. As 

such, OSHA believes that workers will 

experience higher exposures. In order to 

ensure that workers are adequately 

protected, OSHA is proposing that 

employers ensure that workers use halfmask respirators when working under 

shrouds at the point of operation. The 

Agency is seeking comments and 

additional information that address the 

appropriateness of this specification. 

The Agency is also proposing to 

require employers to use a water 

delivery system to suppress dust 

emanating from the dust collector 

exhaust. Research shows that in the 

vicinity of a rock-drilling rig, dust 

collector dumping operations are the 

largest single contributor of airborne 

respirable particulates. Maksimovic and 

Page has shown that in rock-drilling 

rigs, this source contributed 38 percent 

of the respirable dust emissions, while 

the deck shroud contributed 24 percent 

(reported in Reed et al., 2008). NIOSH 

reports that modifications (involving 

water delivery systems) to dust collector 

discharge areas have reduced exposures 

from this source by 63 to 89 percent, 

which means that overall airborne 

particles can be reduced by at least 24 

percent. 

For example, a result of 54 mg/m3 was 

obtained for a worker who operated a rig 

equipped with a vacuum dust collection 

system. This overexposure resulted from 

the lack of dust suppression while dust 

was being dumped from the second 

filter of the collector—not from the 

actual drilling operation. Information 

from the inspection shows that the 

collector had two filters, and water was 

used to suppress dust from dumping 

operations from the first filter only 

(OSHA SEP Inspection Report 

300340908). OSHA believes that adding 

a water delivery system to suppress dust 

from the discharge at the second filter 

would have resulted in a lower 

exposure. This result indicates that the 

control strategy outlined, when applied 

effectively, will adequately protect 

workers during a full work shift without 

requiring respirators. 

Concrete drilling. The control strategy 

for this operation specifies the use of a 

dust collection system around the drill 

bits as well as a low-flow water spray to 

wet the exhaust, operated and 

maintained to minimize dust emissions. 

NIOSH has recommended several 

modifications to typical concrete 

drilling rig dust collection equipment 

(NIOSH EPHB 334–11a, 2008). OSHA 

anticipates that these upgrades will help 

ensure that optimal dust collection 

efficiency is maintained over time. As 

such, the Agency is proposing to require 

these additional specifications: 

• Using smooth ducts and maintaining 

a duct transport velocity of 4,000 feet 

per minute to prevent duct clogging 

• Providing duct clean-out points to aid 

in duct maintenance and prevent 

clogging, and 

• Installing pressure gauges across dust 

collection filters so the operator can 

clean or change the filter at an 

appropriate time 

Furthermore, Minnich 2009 

demonstrated that a dust plume 

originated from the point of operation 

after a worker activated a drill and LEV 

system simultaneously. OSHA believes 

that the overall collection efficiency 

would be improved by activating the 

exhaust suction prior to initiating 

drilling and deactivating it after the drill 

bit stops rotating, and is proposing to 

require that employers operate their 

LEV systems in this manner. 

Similar to rock drilling, OSHA 

believes it is important for employers to 

use dust collectors in accordance with 

manufacturer specifications based on 

the NIOSH findings described in the 

rock drilling section. The Agency is also 

proposing to include a visible dust 

specification for concrete drilling, as it 

will help employers identify potential 

problems with controls. 

While the available data do not 

specifically characterize the effects of 

controls for concrete drilling rigs in all 

circumstances, the Agency has 

substantial data on the effectiveness of 

controls in rock drilling, and based on 

the similarities of these operations (refer 

to PEA, Chapter 4). OSHA estimates that 

these controls provide similar 

protection in concrete drilling and are 

able to reduce and maintain exposures 

to the proposed PEL most of the time. 

Implementing the additional 

specifications listed in Table 1 will also 

provide protection. However, OSHA 

cannot rule out the possibility that silica 

exposures will occasionally exceed the 

PEL, when workers perform this 

operation outside of an enclosed cab for 

more than four hours. Because, in the 

absence of an exposure assessment, 

employers will not be able to confirm 

that exposures are below the PEL, or 

identify circumstances in which 

exposures may exceed the PEL, the 

proposed rule requires that employers 

provide half-mask respirators to workers 

who perform concrete drilling outside of 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56462 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

an enclosed cab for more than four 

hours. 

OSHA seeks additional data to 

describe the efficacy of the controls 

described above in reducing exposures 

for workers who operate concrete 

drilling rigs. Additionally, the Agency is 

requesting comments and additional 

information regarding the adequacy of 

the control strategy described in Table 

1. 

Use of drivable milling machines. 

Table 1 proposes that employers use 

water-fed systems that deliver water 

continuously at the cut point to 

suppress dust, operated and maintained 

to minimize dust emissions. The table 

also includes a visible dust provision, 

which helps employers identify 

potential problems with the control 

strategy. The Agency is proposing that 

no respiratory protection will be 

required for shifts lasting four hours or 

less, and that half-mask respirators be 

used for operations lasting more than 

four hours. 

Some machines are equipped with 

water delivery systems that are 

specifically designed to suppress dust. 

However, water is more generally 

applied to the cutting drum of milling 

machines to prevent mechanical 

overheating. OSHA believes that 

improved water delivery systems will 

help reduce exposures for the worker 

population that remains overexposed. 

For example, a study conducted in the 

Netherlands with a novel dust emission 

suppression system shows the potential 

impact of a water-delivery system 

(combined with an additive) as a control 

strategy. Compared with a standard 

milling machine that uses cooling water 

only on the blade, the use of an 

aerosolized water and foam dust 

suppression system reduced the mean 

exposure for drivers and tenders by 

about 95 and 98 percent, respectively 

(Van Rooij and Klaasse, 2007). The same 

study also reported results for the use of 

aerosolized water without the additive. 

Aerosolized water alone provided a 

substantial benefit, reducing the mean 

exposure for drivers and tenders by 

about 88 and 84 percent, respectively. 

Based on the exposure profile, OSHA 

anticipates that the vast majority of 

workers already experience exposure 

levels below the proposed PEL for 

operations lasting four hours or less. 

With water delivery systems designed 

specifically to suppress dust, the 

Agency expects that workers will be 

consistently protected against respirable 

crystalline silica exposures. With this 

control strategy in place, OSHA believes 

that respirators will not be necessary for 

operations lasting four hours or less. 

OSHA believes that, even when 

workers operate drivable milling 

machines for eight hours, water delivery 

systems will reduce TWA exposures to 

or below the proposed PEL most of time, 

as described in Chapter 4 of the PEA. 

However, OSHA cannot rule out the 

possibility that silica exposures will 

occasionally exceed the PEL under 

certain circumstances, when workers 

operate these machines for more than 

four hours. Because, in the absence of 

an exposure assessment, employers will 

not be able to confirm that exposures are 

below the PEL, or identify 

circumstances in which exposures may 

exceed the PEL, the proposed rule 

requires that employers provide 

respiratory protection to workers who 

operate drivable milling machines for 

more than four hours. 

Based on the range of exposures in the 

exposure profile (see Chapter 4 of the 

PEA), OSHA anticipates that properly 

designed water delivery systems to 

suppress dust and half-mask respirators 

will provide sufficient protection (the 

highest exposure measured for any 

worker is 340 mg/m3, with no dust 

suppression controls in place). As such, 

the Agency believes that using wet 

methods and half-mask respirators is a 

control strategy that consistently 

protects workers for operations lasting 

more than four hours. 

Walking behind milling machines. For 

walk-behind milling machines, Table 1 

provides workers with two options for 

controlling exposures to crystalline 

silica. 

The first option directs employers to 

use water-fed equipment that 

continuously feeds water to the cutting 

surface to suppress dust, operated and 

maintained to minimize dust emissions. 

The exposure profile for this 

operation contains six samples, with the 

highest exposure being the only one 

above the proposed PEL. The two lowest 

exposures in the profile (both are 12 mg/ 

m3) were obtained for workers that used 

water-fed machines (ERG–C, 2008), 

indicating that the wet method 

effectively controls silica exposure. 

If the highest exposure in the profile 

is weighted for four hours, the adjusted 

exposure is less than the proposed PEL. 

Thus, OSHA anticipates that for 

operations lasting four hours or less, 

workers will be consistently protected 

by wet methods. 

OSHA believes that, even when 

workers operate walk-behind milling 

machines for eight hours, water delivery 

systems will reduce TWA exposures to 

or below the proposed PEL most of time, 

as described in Chapter 4 of the PEA. 

However, when workers operate these 

machines for more than four hours, 

silica exposures may occasionally 

exceed the PEL under certain 

circumstances. Because, in the absence 

of an exposure assessment, employers 

will not be able to confirm that 

exposures are below the PEL, or identify 

circumstances in which exposures may 

exceed the PEL, the proposed rule 

requires that employers provide 

respiratory protection to workers who 

operate walk-behind milling machines 

for more than four hours. The Agency 

believes the use of a half-mask 

respirator will ensure consistent worker 

protection. 

The second option is to use tools 

equipped with commercially available 

shrouds and dust collection systems, 

which are operated and maintained to 

minimize dust emissions. The dust 

collector must be equipped with a 

HEPA filter and must operate at an 

adequate airflow to minimize airborne 

visible dust. Additionally, the dust 

collector must be used in accordance 

with manufacturer specifications 

including the airflow rate. 

To date OSHA has not been able to 

quantify the effectiveness of currently 

available LEV in controlling respirable 

quartz levels associated with walkbehind milling operations; however, 

OSHA believes that evidence from 

similar construction tasks supports its 

value for workers performing milling. 

OSHA believes that the LEV dust 

control option will work at least as 

effectively for milling machines as for 

tuckpointing grinders. Although the 

tuckpointers using LEV still 

experienced a geometric mean result of 

60 mg/m3, walk-behind milling machine 

operators have the advantages of lower 

uncontrolled exposure levels, greater 

distance between the tool and their 

breathing zone, and equipment that is 

self-supporting (the milling drum 

enclosure more easily kept sealed 

against the floor), rather than hand-held. 

Therefore, an LEV system with an 

appropriately sized vacuum will 

similarly reduce most walk-behind 

milling machine operator exposures. 

Based on the exposure samples 

analyzed, OSHA estimates that most 

workers already have exposures under 

the proposed PEL for operations lasting 

four hours or less, and is not proposing 

to require respirator use. 

For operations lasting more than four 

hours, the Agency believes that at most 

the workers will be protected by using 

LEV alone, as described Chapter 4 of the 

PEA. However, the Agency cannot rule 

out the possibility that workers who 

operate these machines for more than 

four hours will occasionally receive 

exposures that exceed the PEL, under 

certain circumstances. Because, in the 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56463 

absence of an exposure assessment, 

employers will not be able to confirm 

that exposures are below the PEL, or 

identify circumstances in which 

exposures may exceed the PEL, the 

proposed rule requires that employers 

provide half-mask respirators to workers 

who operate drivable milling machines 

for more than four hours. 

Use of hand-held masonry saws. 

Table 1 provides employers with two 

different control strategies. Along with 

the engineering controls listed in Table 

1, OSHA is proposing the additional 

specifications that will aid employers in 

using the engineering controls 

optimally. 

• Prevent wet slurry from 

accumulating and drying. The 

accumulation and drying of wet slurry 

can lead to settled dust that is easily 

resuspended and can contribute to 

worker exposures. 

• Ensure that the equipment is 

operated such that no visible dust is 

emitted from the process. When controls 

are functioning properly, visible dust 

should not be observed. This 

specification will help employers 

identify potential problems with the 

control strategy. 

• When working indoors, provide 

sufficient ventilation to prevent buildup of visible airborne dust. Proper 

airflow prevents air from becoming 

stagnant and dilutes the levels of 

respirable crystalline silica. 

• Use dust collectors in accordance 

with manufacturer specifications. 

Selecting the correct system and flow 

rates will consistently reduce exposure. 

Option 1: Employers use a water-fed 

system that delivers water continuously 

at the cut point, operated and 

maintained to minimize dust emissions. 

The exposure profile for outdoor 

cutting with wet methods shows that for 

shift lasting four hours or less, workers 

consistently experience exposure below 

the proposed PEL. The Agency believes 

that wet methods alone will provide 

protection and is proposing to require 

that employers apply the wet method 

control without the use of respiratory 

protection. 

OSHA believes that, even when 

workers operate hand-held masonry 

saws outdoors for eight hours, wet 

methods will reduce TWA exposures to 

or below the proposed PEL most of time, 

as described in Chapter 4 of the PEA. 

However, on the basis of the two highest 

sample results in the exposure profile 

(see Chapter 4 of the PEA), the Agency 

believes that silica exposures may 

occasionally exceed the PEL under 

certain circumstances, when workers 

perform these operations outdoors for 

more than four hours. Because, in the 

absence of an exposure assessment, 

employers will not be able to confirm 

that exposures are below the PEL, or 

identify circumstances in which 

exposures may exceed the PEL, the 

proposed rule requires that employers 

provide half-mask respirators to workers 

who operate hand-held masonry saws 

outdoors for more than four hours. 

Similarly, the highest readings in the 

exposure profile for operations using 

wet methods indoors suggest that silica 

exposures may sometimes exceed the 

PEL even for workers who perform these 

activities for less than four hours. 

Therefore, the Agency is proposing to 

require the use of a half-mask respirator 

with an APF of 10 for workers who 

operate hand-held masonry saws 

indoors or within a partially sheltered 

area, regardless of task duration. 

Option 2: Use a saw equipped with a 

local exhaust dust collection system, 

operated and maintained to minimize 

dust emissions. 

While the exposure profile does not 

contain any samples for work involving 

hand-held masonry saws conducted 

with LEV in place, several studies have 

shown the general effectiveness of LEV 

to reduce silica concentrations. Meeker 

et al. (2009) shows that LEV can reduce 

respirable silica exposures to levels near 

100 mg/m3 during short-term periods of 

active cutting outdoors. Since most 

workers cut intermittently even during 

times of active cutting (e.g., 10 or 20 

seconds using the saw followed by a 

longer period—up to several minutes— 

of measuring and moving materials or 

equipment), 8-hour TWA values are 

likely to be considerably lower 

(Flanagan et al., 2001). However, OSHA 

has not been able to confirm that LEV 

methods offer the same degree of 

exposure reduction to workers currently 

experiencing more modest, but still 

elevated, exposures. 

Thus, the Agency cannot rule out the 

possibility that silica exposures will 

sometimes exceed the PEL, even when 

workers perform these operations for 

less than four hours. Because, in the 

absence of an exposure assessment, 

employers will not be able to confirm 

that exposures are below the PEL, or 

identify circumstances in which 

exposures may exceed the PEL, the 

proposed rule requires that employers 

provide half-mask respirators to workers 

who use LEV to control exposures while 

operating hand-held masonry saws 

outdoors. 

While OSHA does not have exposure 

data to specifically describe indoor 

operations using LEV controls, Thorpe 

et al. (1999) and Meeker et al. (2009) 

reported exposure reductions by 88 to 

93 percent for outdoor operation. OSHA 

believes that these exposure reductions 

would be similar in indoor operations 

because there is no added general 

ventilation in these environments such 

as natural air circulation outdoors and 

airborne dust tends to become more 

stagnant indoors. Given the very high 

uncontrolled exposures documented in 

the Chapter 4 of the PEA, even the 

projected exposure reduction from LEV 

does not rule out the possibility that 

exposures above 500 mg/m3 will 

occasionally occur under certain 

circumstances. Because, in the absence 

of an exposure assessment, employers 

will not be able to confirm that 

exposures are below the PEL, or identify 

circumstances in which exposures may 

exceed the PEL, the proposed rule 

requires that employers provide full 

face-piece respirators to workers who 

operate hand-held masonry saws 

indoors or in partially enclosed areas, 

regardless of task duration. 

Use of portable walk-behind or 

drivable masonry saws. Table 1 directs 

employers to use a water-fed system that 

delivers water continuously at the cut 

point, operated and maintained to 

minimize dust emissions with the 

following specifications: 

• Prevent wet slurry from 

accumulating and drying. The 

accumulation and drying of wet slurry 

can lead to settled dust that is easily 

resuspended and can contribute to 

worker exposures. 

• Ensure that the equipment is 

operated such that no visible dust is 

emitted from the process. When controls 

are functioning properly, visible dust 

should not be observed. This 

specification will help employers 

identify potential problems with the 

control strategy. 

• When working indoors, provide 

sufficient ventilation to prevent buildup of visible airborne dust. Proper 

airflow prevents air from becoming 

stagnant and dilutes the levels of 

respirable crystalline silica. 

The exposure profile for this 

operation shows that of the 12 

respirable silica results associated with 

wet-cutting concrete outdoors using 

walk-behind saws, only 1 measurement 

exceeded the proposed PEL, while 8 

were less than the LOD. These results 

suggest that for outdoor operations, 

water-fed walk-behind saws provide 

adequate protection for workers. 

Based on this information, OSHA 

believes that by using the wet method 

controls as specified, workers will be 

provided with consistent, adequate 

protection and is proposing to not 

require the use of a respirator when 

working outdoors. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56464 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

Flanagan et al. (2001) reported higher 

8-hour TWA respirable silica levels for 

operators and their assistants who used 

water-fed walk-behind saws indoors for 

most of their shift (the worst-case 

conditions resulted in four 8-hour TWA 

values between 130 mg/m3 and 710 mg/ 

m3). The author noted that factors such 

as inadequate ventilation or poor wet 

vacuum capture efficiency contributed 

to the higher indoor respirable silica 

levels. 

By applying the additional 

specifications and engineering controls 

outlined in Table 1, OSHA believes that 

indoor exposures will be reduced to 

levels where respiratory protection with 

an APF of 10 will provide adequate 

protection. OSHA is proposing to 

require the use of a half-mask respirator 

for tasks of all duration when working 

indoors or in partially shielded areas. 

Rock crushing. Table 1 provides 

employers with two control strategies to 

protect employees not working in 

enclosed cabs. Both options (described 

below) require the use of half-mask 

respirators regardless of task duration. 

For equipment operators working 

within an enclosed cab, OSHA is 

proposing that cabs have the following 

characteristics: (1) air conditioning and 

positive pressure is maintained at all 

times, (2) incoming air is filtered 

through a pre-filter and a HEPA filter, 

(3) the cab is maintained as free as 

practicable from settled dust, and (4) 

door seals and closing mechanisms are 

working properly. Cecala et al. (2005) 

studied modifications designed to lower 

respirable dust levels in an enclosed cab 

on a 20-year-old surface drill at a silica 

sand operation. The study found that 

effective filtration and cab integrity (e.g., 

new gaskets, sealed cracks to maintain 

a positive-pressure environment) are the 

two key components necessary for dust 

control in an enclosed cab. OSHA 

believes that the cab specifications 

outlined will promote proper air 

filtration and cab integrity. OSHA is 

proposing that operators who work in 

enclosed cabs meeting these 

specifications will not be required to 

wear respirators. 

OSHA is also proposing an additional 

specification, which requires that dust 

control equipment be operated such that 

no visible dust is emitted from the 

process. When controls are functioning 

properly visible dust should not be 

observed, and this specification will 

help employers identify potential 

problems with the control strategy. 

Option 1: Use wet methods or dust 

suppressants. 

Based on available information, 

OSHA believes that water or other dust 

suppression is used during rock 

crushing activities but that the 

application may be either inconsistent 

or inefficient (ERG–C, 2008). However, 

the Agency has obtained other 

information that shows that dust 

suppression systems have been effective 

in reducing exposures. For example, a 

silica result of 54 mg/m3 was obtained 

for the operator of a stationary crusher 

at a concrete recycling facility using fine 

mist water spray (ERG-concr-crush-A, 

2001). It is important to note that this 

machine operator spent much of the 

shift in a poorly sealed booth directly 

over the crusher, but left the booth 

frequently to tend to other activities. 

Due to the lack of information regarding 

the workshift, OSHA cannot asses the 

full extent of the impact that water dust 

control had on the worker exposure. 

Gottesfeld et al. (2008) summarized a 

study conducted in India at several rock 

crushing facilities. The study 

demonstrates that after water spray 

installation, 70 percent of the breathing 

zone and area results were less than 50 

mg/m3, and just one result exceeded 250 

mg/m3. In contrast, before the water mist 

system was added, all results exceeded 

50 mg/m3, and 60 percent were greater 

than 250 mg/m3, a condition similar to 

those in OSHA’s exposure profile for 

workers associated with rock crushing 

machines. OSHA acknowledges that 

worksites may different in the United 

States, but believes that similar 

exposure reductions can be achieved 

with rock crushers in the U.S. 

Wet dust suppression options that can 

offer a substantial benefit include water 

expanded into foam, steam, compressed 

water fog, and wetting agents 

(surfactants added to water to reduce 

surface tension) (ERG–C, 2008). OSHA 

believes that when used properly and 

consistently, these dust suppressants 

could reduce silica concentrations at 

least as effectively as and more 

consistently than directional water mist 

spray alone, achieving exposure 

reductions of 70- to 90-percent. 

OSHA acknowledges that available 

data is inadequate to indicate whether 

water mist or other dust suppressants 

alone are sufficient to reduce these 

workers’ silica exposures below 50 mg/ 

m3. However, based on the best 

available information, OSHA estimates 

that by consistently using properly 

directed water mist spray (or other dust 

suppression methods), the vast majority 

of rock crushers can achieve consistent 

results in a range that is compatible 

with use of a half-mask respirator with 

an APF of 10. 

Option 2: Use local exhaust 

ventilation systems at feed hoppers and 

along conveyor belts, operated and 

maintained to minimize dust emissions. 

Information available to OSHA 

indicates that LEV is capable of 

reducing silica concentrations. For 

example, Ellis Drewitt (1997) reported a 

reading of 300 mg/m3 for a worker in 

Australia using a dust extraction system 

(when compared to the uncontrolled 

mean of 798 mg/m3 in the exposure 

profile). 

Another international report from Iran 

describes a site where workers used 

rock crushers with LEV (Bahrami et al., 

2008). The report demonstrated that 

LEV systems were associated with a 

marked decrease in respirable dust. 

Among 20 personal silica samples for 

process workers and hopper-filling 

workers associated with rock crushers 

after LEV was installed, the mean PBZ 

respirable quartz results were 190 mg/m3

to 400 mg/m3, respectively. It is 

important to note that the bulk samples 

of this rock contained 85 to 97 percent 

quartz. The Agency believes that these 

levels would likely have been lower if 

the rock had not been nearly pure silica. 

If the respirable dust sample had 

contained the more typical 12 percent 

silica on the filter, OSHA estimates that 

the corresponding airborne silica 

concentrations would have been 92 mg/ 

m3 to 178 mg/m3. The Agency recognizes 

that exposures may be higher than this 

estimate, but does not possess 

additional information that more clearly 

characterizes worker exposures with the 

implementation of LEV controls. 

As such, OSHA believes that a fully 

functioning LEV system can control 

exposures for most workers to within 

the protection factor offered by a halfmask respirator. OSHA is aware of the 

difficulties present in applying LEV to 

rock crushing operations, and is 

requesting additional information 

addressing the appropriateness and 

practicability of this control strategy. 

Drywall finishing (with silicacontaining material). The main source 

of exposure for drywall finishing 

operations occurs when dust is 

generated while sanding dried, silicacontaining joint compound (ERG–C, 

2008). Fourteen of the 15 samples 

collected for the exposure profile for 

this operation show exposures below 

the proposed PEL, with 7 samples below 

the LOD. The one overexposure, 72 mg/ 

m3, was obtained for a worker 

performing overhead sanding (NIOSH 

HETA 94–0078–2660, 1997). Table 1 

provides employers with two control 

strategies; neither option requires the 

use of respirators. 

Option 1: Use pole sander or hand 

sander equipped with a dust collection 

system, operated and maintained to 

minimize dust emissions. Use dust 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56465 

39 Intratracheal instillation is an alternative to 

inhalation exposure studies. Test material is 

delivered in a bolus aqueous solution to the lung 

through a syringe and ball-tipped needle into the 

tracheal (Phalen, 1984). 

collectors according to manufacturer 

specifications. 

NIOSH tested the effectiveness of five 

off-the-shelf ventilated sanding systems 

during drywall finishing: three designed 

to control dust during pole sanding, and 

two to control dust during hand 

sanding. Total dust area sample results 

revealed that all five systems were 

effective for reducing total airborne dust 

by at least 80 percent, ranging up to 97 

percent (NIOSH ECTB–208–11a, 1995). 

This effectiveness was confirmed in a 

study by Young-Corbett and Nussbaum 

(2009a), which found that using a 

ventilated sander during drywall 

sanding reduced respirable dust in the 

PBZ by 88 percent compared with a 

block sander (no controls). 

Silica exposures were not measured 

explicitly in these studies, but OSHA 

estimates that based on the reported 

total dust reductions, even the highest 

exposure in the profile can be reduced 

to levels below the proposed PEL. The 

Agency reasonably estimates that this 

control strategy will adequately protect 

workers without the need for 

respirators. 

Although ventilated sanders are the 

most effective exposure control option 

for silica-containing joint compound, 

and they offer indirect benefits to 

workers and managers (NIOSH Appl. 

Occup. Environ. Hyg. 15, 2000), there 

are many perceived barriers to their 

adoption in the workplace (NIOSH 

ECTB–208–11a, 1995; Young-Corbett 

and Nussbaum, 2009b). Hence, Option 2 

is provided to employers as a way to 

comply with paragraph (f)(1) of the 

proposed rule. 

Option 2: Use wet methods to smooth 

or sand the drywall seam. 

Young-Corbett and Nussbaum (2009a) 

found that a wet sponge sander reduces 

respirable dust in the PBZ by 60 percent 

compared with a block sander (no 

controls). Other wet methods include 

wiping a clean, damp sponge over the 

still-damp joint compound to smooth 

the seam and rinsing the sponge in a 

bucket of water as it becomes loaded 

with compound, or wetting dried joint 

compound with a spray bottle and 

sanding with sandpaper (NIOSH ECTB– 

208–11a, 1995). 

Again, silica exposures were not 

explicitly measured in the YoungCorbett and Nussbaum study. Based on 

the reported respirable dust reduction, 

however, OSHA estimates that even the 

highest exposure in the profile can be 

reduced and maintained below the 

proposed PEL. As such, the Agency 

believes that using wet methods will 

offer adequate protection without 

requiring respirators. 

Use of heavy equipment during 

earthmoving. The exposure profile for 

this operation ranges from 11 mg/m3 to 

170 mg/m3, with about 13 percent of the 

values exceeding the proposed PEL. 

Table 1 provides for the option of 

operating equipment from enclosed cabs 

to control exposures. It specifies that 

workers operate equipment from within 

enclosed cabs that have the following 

characteristics: 

• Air conditioning with positive 

pressure maintained at all times; 

• Incoming air filtered through a prefilter and a HEPA filter; 

• Having the cab be as free as 

practicable from settled dust; and 

• Door seals and closing mechanisms 

that are working properly. 

Based on published research, ERG–C 

(2008) found that effective enclosed 

cabs generally have these four 

characteristics, and extensive literature 

suggests that the exposure reductions 

can range from 80 to more than 90 

percent in this industry (Rappaport et 

al., 2003; Pannel and Grogin, 2000; 

Cecala et al., 2005; NIOSH 528, 2007). 

The exposure profile shows that of the 

19 results for which the status of the cab 

was established, 17 were for unenclosed 

cabs. Both of the operations involving 

enclosed cabs had exposures of about 12 

mg/m3, while operations involving 

several of the unenclosed cabs were 

associated with worker exposures 

greater than 50 mg/m3 and up to 87 mg/ 

m3. This information allows OSHA to 

determine that operators using enclosed 

cabs as proposed by this option will 

effectively protect workers. Respiratory 

protection will not be needed. 

Concerning abrasive blasting 

operations, paragraph (f)(2) of the 

general industry/maritime proposed 

rule and paragraph (f)(3) of the 

construction proposed rule direct 

employers to comply with the 

requirements of 29 CFR 1910.94 

(Ventilation), and for shipyard 

employment 29 CFR 1915.34 

(Mechanical Paint Removers) and 29 

CFR part 1915, subpart I (Personal 

protective equipment). These standards 

apply to abrasive blasting operations 

that involve crystalline silica-containing 

blasting agents or substrates. Employers 

should consult these other standards to 

ensure that they comply with personal 

protective equipment, ventilation, and 

other operation-specific safety 

requirements. 

OSHA is aware of current and past 

efforts of domestic and international 

entities to ban silica sand as an abrasive 

blasting agent. Given the best available 

information to date, the Agency does 

not believe that banning silica sand is 

the most appropriate course of action, as 

OSHA has concerns about potential 

harmful exposures to other substances 

that the alternatives might introduce in 

a workplace. Further toxicity data are 

necessary before the Agency can reach 

any conclusions about the hazards of 

these substitutes relative to the hazards 

of silica. The following paragraphs 

provide further information regarding 

abrasive blasting agents. 

The annual use of silica sand for 

abrasive blasting operations has 

decreased from about 1.5 million tons in 

1996 to 0.5 million tons in 2007, which 

roughly represents a 67-percent 

reduction (Greskevitch and Symlal, 

2009)). This reduction might reflect the 

use of alternative blasting media, the 

increased use of high-pressure waterjetting techniques, and the use of 

cleaning techniques that do not require 

open sand blasting. Several substitutes 

for silica sand are available for abrasive 

blasting operations, and current data 

indicate that the abrasive products with 

the highest U.S consumptions are: coal 

slag, copper slag, nickel slag, garnet, 

staurolite, olivine, steel grit, and 

crushed glass. 

A NIOSH study compared the shortterm pulmonary toxicity of several 

abrasive blasting agents (NIOSH, 

Blasting Abrasives: Health Hazard 

Comparison, 2001). This study reported 

that specular hematite and steel grit 

presented less short-term in vivo 

toxicity and respirable dust exposure in 

comparison to blast sand. Overall, 

crushed glass, nickel glass, staurolite, 

garnet, and copper slag were similar to 

blast sand in both categories. Coal slag 

and olivine showed more short-term in 

vivo toxicity than blast sand and were 

reported as similar to blast sand 

regarding respirable dust exposure. This 

study did not examine long-term 

hazards or non-lung effects. 

Hubbs et al. (2005) mention that of the 

nine alternatives to silica sand, NIOSH 

has identified five of them–coal slag, 

steel grit, specular hematite, garnet, and 

crushed glass–for further testing to 

determine the relative potential of these 

agents to induce lung fibrosis in rats 

exposed to whole-body inhalation. 

These abrasive materials were selected 

for study based on high production, 

number of workers exposed, short-term 

intratracheal instillation 39 relative 

toxicity studies, and inadequacy of 

available current data (Hubbs et al., 

2005). The National Toxicology Program 

is performing long-term (39 weeks), in 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56466 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

vivo, toxicity studies of these abrasive 

blasting agents. 

Additionally, another NIOSH study 

(KTA-Tator, 1998) monitored exposures 

to several OSHA-regulated toxic 

substances that were created by the use 

of silica sand and substitute abrasive 

blasting materials. The study showed 

that several substitutes create exposures 

or potential exposures to various OSHAregulated substances. The study showed 

exposures or potential exposures to: (1) 

Arsenic, when using steel grit, nickel 

slag, copper slag and coal slag; (2) 

beryllium, when using garnet, copper 

slag, and coal slag; (3) cadmium, when 

using nickel slag and copper slag; (4) 

chromium, when using steel grit, nickel 

slag, and copper slag; and (5) lead, when 

using copper slag. 

Since these studies were performed, 

the Agency has learned that specular 

hematite is not being manufactured in 

the United States due to patent-owner 

specification. In addition, the elevated 

cost of steel has a substantial impact on 

the availability to some employers to 

use substitutes like steel grit and steel 

shot. 

Elevated silica exposures have been 

found during the use of low-silica 

abrasives as well, even when blasting on 

non-silica substrates. For example, the 

use of the blasting media Starblast XL 

(staurolite), which contains less than 1 

percent quartz according to its 

manufacturer, resulted in a respirable 

quartz level of 1,580 mg/m3. The area 

sample (369-minute) was taken inside a 

containment structure erected around 

two steel tanks. The elevated exposure 

occurred because the high levels of 

abrasive generated during blasting in 

containment overwhelmed the 

ventilation system (NIOSH, 1993b). This 

example emphasizes the impact of 

control methods in specific working 

environments. In order to reduce 

elevated exposures closer to the PEL in 

situations like these, employers should 

examine the full spectrum of available 

controls, and how these controls 

perform in specific working conditions. 

Employers may find, for example, that 

they would have to provide 

supplementary respiratory protection to 

adequately protect workers that perform 

abrasive blasting in areas where the 

accumulation of dust remains stagnant 

(e.g. confined spaces) in a worker’s 

personal breathing zone and 

overwhelms exhaust ventilation 

systems. Other engineering controls the 

same employer may consider would be 

wet and/or automated blasting. 

Paragraph (f)(4) of the construction 

proposed rule, and Paragraph (f)(3) of 

the general industry/maritime proposed 

rule specify that accumulations of 

crystalline silica in the work place are 

to be cleaned by HEPA-filter vacuums or 

wet methods. This section also prohibits 

the use of compressed air, dry sweeping, 

and dry brushing to clean clothing or 

surfaces contaminated with crystalline 

silica. These requirements are being 

proposed to help regulate the amount of 

crystalline silica that becomes airborne, 

thus providing effective control of 

worker exposure. The requirements of 

paragraph (f)(4) are consistent with 

general industry standards for 

hazardous substances, such as cadmium 

and asbestos, which specify that work 

surfaces be cleaned wherever possible 

by vacuuming with a HEPA-filtered 

vacuum. Much documentation shows 

that moving from compressed air 

blowing and dry sweeping to HEPAfiltered vacuums and the application of 

wet methods effectively reduces worker 

exposures during cleaning activities 

(PEA, Chapter 4). 

A study of Finnish construction 

workers compared the respirable 

crystalline silica levels during dry 

sweeping or when using alternative 

cleaning methods. Compared with dry 

sweeping, estimated worker exposures 

were about three times lower when 

workers used wet sweeping and five 

times lower when they used vacuums. 

In the asphalt roofing industry, NIOSH 

and OSHA both recommended 

vacuuming with HEPA-filtered vacuums 

as a method to minimize exposure. In 

five Health Hazard Evaluations at 

asphalt roofing manufacturing facilities, 

NIOSH recommended vacuuming as 

opposed to compressed air for cleaning 

dust out of equipment (ERG–GI, 2008). 

OSHA’s technological feasibility 

analysis points to numerous other 

instances where cleaning methods are of 

particular importance in reducing 

worker exposures. In the rock and 

concrete drilling industry, OSHA 

recommends that workers use HEPAfiltered vacuums instead of compressed 

air to clean holes in order to reduce–or 

even eliminate–substantial exposure 

during hole-tending activities. In the 

porcelain enameling industry, a facility 

has used a vacuum fitted with a HEPA 

filter for all cleaning. To minimize 

generating airborne dust, workers avoid 

dry sweeping and only shovel or scrape 

materials that are damp (Porcelain 

Industries, 2004a; 2004b). 

For millers using portable or mobile 

equipment, Echt et al. (2002) reported 

that cleanup is critical for engineering 

controls to work most effectively for 

walk-behind milling machines. The 

study reported that airborne dust 

increased when a scabbler passed over 

previously milled areas. It was 

recommended that debris be cleaned 

using a HEPA-filtered vacuum prior to 

making a second pass over an area. This 

step enhanced LEV capability and 

prevented debris from being resuspended. 

Several facilities have adopted the 

recommended cleaning methods as part 

as an overall effort to reduce exposures. 

For example, in the jewelry and dental 

laboratories industries, additional 

controls to reduce exposures below the 

proposed PEL include LEV, wet 

methods, substitution, isolation, work 

practices, and improved housekeeping 

such as the use of a HEPA-filtered 

vacuum for cleaning operations. These 

examples again also show the value of 

applying a combination of controls to 

reduce exposures below the PEL. 

Paragraph (f)(5) of the construction 

proposed rule, and Paragraph (f)(4) of 

the general industry/maritime proposed 

rule specify that the employer must not 

rotate workers to different jobs to 

achieve compliance with the PEL. 

OSHA proposes this prohibition 

because silica is a carcinogen, and the 

Agency assumes that any level of 

exposure to a carcinogen places a 

worker at risk. With worker rotation, the 

population of exposed workers 

increases. 

This provision is not a general 

prohibition of worker rotation wherever 

workers are exposed to crystalline silica. 

It is only intended to restrict its use as 

a compliance method for the proposed 

PEL; worker rotation may be used as 

deemed appropriate by the employer in 

activities such as to provide crosstraining and to allow workers to 

alternate physically demanding 

operations with less arduous ones. This 

same provision was used for the 

asbestos (29 CFR 1910.1001 and 29 CFR 

1926.1101), hexavalent chromium (29 

CR 1910.1026), butadiene (29 CFR 

1910.1051), methylene chloride (29 CFR 

1910.1052), cadmium (29 CFR 

1910.1027 and 29 CFR 1926.1127), and 

methylenedianiline (29 CFR 1926.60) 

OSHA standards. 

(g) Respiratory Protection 

During situations where employee 

exposure to respirable crystalline silica 

is expected to be above the PEL, 

paragraph (g) requires the employer to 

protect employees’ health through the 

use of respirators. Specifically, in areas 

where exposures exceed the PEL, 

respirators are required during the 

installation and implementation of 

engineering and work practice controls; 

during work operations where 

engineering and work practice controls 

are not feasible; when all feasible 

engineering and work practice controls 

have been implemented but are not 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56467 

sufficient to reduce exposure to or 

below the PEL; and during periods 

when any employee is in a regulated 

area or an area for which an access 

control plan indicates that use of 

respirators is necessary. 

These limitations on the required use 

of respirators are generally consistent 

with other OSHA health standards, such 

as methylene chloride (29 CFR 

1910.1052) and chromium (VI) (29 CFR 

1910.1026). They reflect the Agency’s 

determination, discussed above in 

section (f) (Methods of compliance), that 

respirators are inherently less reliable 

than engineering and work practice 

controls in reducing employee exposure 

to respirable crystalline silica. OSHA 

has therefore proposed to allow reliance 

on respirators only in certain designated 

situations. 

Proposed paragraph (g)(1)(i) requires 

the use of respirators in areas where 

exposures exceed the PEL during 

periods when engineering and/or work 

practice controls are being installed or 

implemented. OSHA recognizes that 

respirators may be essential to achieve 

the PEL under these circumstances. 

During these times, employees would 

have to use respirators for temporary 

protection until the hierarchy of 

controls has been implemented. 

OSHA anticipates that engineering 

controls will be in place by the start-up 

date specified in paragraph (k)(2)(ii) of 

the construction and the general 

industry/maritime proposed standards. 

The Agency realizes that in some cases 

employers may commence operations, 

install new or modified equipment, or 

make other workplace changes that 

result in new or additional exposures to 

crystalline silica after the effective date 

as defined by paragraph (k)(1). In these 

cases, a reasonable amount of time may 

be needed before appropriate 

engineering controls can be installed 

and proper work practices 

implemented. When employee 

exposures exceed the PEL in these 

situations, employers must provide their 

employees with respiratory protection 

and require its use. 

Proposed paragraph (g)(1)(ii) requires 

respiratory protection in areas where 

exposures exceed the PEL during work 

operations in which engineering and 

work practice controls are not feasible. 

OSHA anticipates that there will be few 

situations where no feasible engineering 

or work practice controls are available 

to limit employee exposure to respirable 

crystalline silica. In situations where 

respirators are used as the sole form of 

protection to achieve compliance with 

the PEL, the employer will be required 

to demonstrate that engineering and 

work practice controls are not feasible. 

Proposed paragraph (g)(1)(iii) requires 

the use of respirators for supplemental 

protection in circumstances where 

feasible engineering and work practice 

controls alone cannot reduce exposure 

levels to or below the PEL. Examples 

include some tuckpointing, 

jackhammering, and abrasive blasting 

operations. The employer must always 

install and implement engineering and 

work practice controls whenever they 

are feasible, even if these controls alone 

cannot reduce employee exposures to or 

below the PEL. Whenever respirators are 

used as supplemental protection to 

achieve compliance with the PEL, the 

burden is on the employer to 

demonstrate that engineering and work 

practice controls alone are insufficient 

to achieve the PEL. 

Under proposed paragraph (g)(1)(iv), 

employers have to provide respiratory 

protection during periods when any 

employee is in a regulated area. 

Proposed paragraph (e) in the general 

industry/maritime standard and 

proposed paragraph (e)(2) in the 

construction standard would require 

employers to establish a regulated area 

wherever an unprotected employee’s 

exposure to airborne concentrations of 

respirable crystalline silica is, or can 

reasonably be expected to be, in excess 

of the PEL. OSHA has included the 

provision requiring respirator use in 

regulated areas in the proposed rule to 

make it clear that each employee is 

required to wear a respirator when 

present in a regulated area, regardless of 

the duration of time spent in the area. 

Because of the potentially serious 

results of exposure, OSHA believes that 

this provision is necessary and 

appropriate because it would have the 

effect of limiting unnecessary exposures 

to employees who enter regulated areas, 

even if they are only in a regulated area 

for a short period of time. 

Proposed paragraph (e)(3) gives the 

employer the option of developing an 

access control plan as a means of 

minimizing exposures to employees not 

directly involved in operations that 

generate respirable crystalline silica. 

This written access control plan would 

serve as an alternative to setting up 

regulated areas under paragraph (e)(2). 

An access control plan must include 

procedures for providing and requiring 

the use of respiratory protection in areas 

where exposures can reasonably be 

expected to exceed the PEL. Proposed 

paragraph (g)(1)(v) of the construction 

standard requires the use of respiratory 

protection when specified by the access 

control plan. 

Proposed paragraph (g)(2) requires the 

employer to implement a 

comprehensive respiratory protection 

program in accordance with the 

Agency’s respiratory protection 

standard (29 CFR 1910.134) whenever 

respirators are used to comply with the 

requirements of the respirable 

crystalline silica standard. The 

respiratory protection program is 

designed to ensure that respirators are 

properly used in the workplace and are 

effective in protecting workers. The 

program must include: procedures for 

selecting respirators for use in the 

workplace; medical evaluation of 

employees required to use respirators; 

fit-testing procedures for tight-fitting 

respirators; procedures for proper use of 

respirators in routine and reasonably 

foreseeable emergency situations; 

procedures and schedules for 

maintaining respirators; procedures to 

ensure adequate quality, quantity, and 

flow of breathing air for atmospheresupplying respirators; training of 

employees in respiratory hazards to 

which they might be exposed and the 

proper use of respirators; and 

procedures for evaluating the 

effectiveness of the program. 

In 2006, OSHA revised the respiratory 

protection standard (29 CFR 1910.134) 

to include assigned protection factors 

(71 FR 50122, Aug. 24, 2006). Assigned 

protection factor means the workplace 

level of respiratory protection that a 

respirator or class of respirators is 

expected to provide to employees when 

the employer implements a respiratory 

protection program under 29 CFR 

1910.134. The revised standard includes 

a table (Table 1—Assigned Protection 

Factors) that employers must use to 

select sufficiently protective respirators 

for employees who may be exposed to 

respirable crystalline silica. 

Proposed paragraph (g)(3) for the 

construction standard indicates that, for 

the operations listed in Table 1 in 

paragraph (f) of the construction 

standard, if the employer fully 

implements the engineering controls, 

work practices, and respiratory 

protection described in Table 1, the 

employer shall be considered to be in 

compliance with the requirements for 

selection of respirators in 29 CFR 

1910.134 paragraph (d). Paragraph (d) of 

29 CFR 1910.134 requires the employer 

to evaluate respiratory hazards in the 

workplace, identify relevant workplace 

and user factors, and base respirator 

selection on these factors. There is no 

need for the employer to complete this 

process when following Table 1, 

because Table 1 specifies the type of 

respirator required for a particular 

operation. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56468 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

(h) Medical Surveillance 

In paragraph (h)(1)(i), OSHA proposes 

to require that each employer covered 

by this rule make medical surveillance 

available at no cost, and at a reasonable 

time and place, for all employees who 

are occupationally exposed to respirable 

crystalline silica above the PEL for 30 or 

more days per year. 

There is a general consensus that 

medical surveillance is necessary for 

employees exposed to respirable 

crystalline silica. Medical surveillance 

for workers exposed to respirable 

crystalline silica is included in 

standards developed by ASTM 

International (ASTM, 2006; 2009) as 

well as in guidance or recommendations 

developed by the American College of 

Occupational and Environmental 

Medicine (ACOEM, 2006), the Building 

and Construction Trades Department, 

AFL–CIO (BCTD, 2001), the Industrial 

Minerals Association/Mine Safety and 

Health Administration (IMA/MSHA, 

2008), National Industrial Sand 

Association (NISA, 2010), and the 

World Health Organization (WHO, 

1996). Although the specific 

recommendations made by these 

organizations differ in certain respects, 

they are consistent in indicating that 

regular medical examinations are 

appropriate for workers with substantial 

exposures to respirable crystalline 

silica. 

The purposes of medical surveillance 

for respirable crystalline silica include 

the following: to determine, where 

reasonably possible, if an individual can 

be exposed to respirable crystalline 

silica in his or her workplace without 

experiencing adverse health effects; to 

identify respirable crystalline silicarelated adverse health effects so that 

appropriate intervention measures can 

be taken; and to determine the 

employee’s fitness to use personal 

protective equipment such as 

respirators. The proposal is consistent 

with Section 6(b)(7) of the OSH Act (29 

U.S.C. 655(b)(7)) which requires that, 

where appropriate, medical surveillance 

programs be included in OSHA 

standards to determine whether the 

health of workers is adversely affected 

by exposure to the hazard addressed by 

the standard. Other OSHA health 

standards, such as chromium (VI) (29 

CFR 1910.1026), methylene chloride (29 

CFR 1910.1052), and cadmium (29 CFR 

1910.1027), also include medical 

surveillance requirements. 

The proposed standard is intended to 

encourage participation by requiring 

that medical examinations be made 

available by the employer without cost 

to employees (also required by Section 

6(b)(7) of the Act), and at a reasonable 

time and place. If participation requires 

travel away from the worksite, the 

employer is required to bear the cost. 

Employees must be paid for time spent 

taking medical examinations, including 

travel time. 

OSHA is proposing that medical 

surveillance be made available to 

employees exposed to respirable 

crystalline silica above the PEL for 30 or 

more days a year. In contrast, the ASTM 

standards (Section 4.6.1) require 

medical surveillance for workers with 

actual or anticipated exposures to 

respirable crystalline silica at 

concentrations that exceed the 

occupational exposure limit for 120 or 

more days a year (ASTM, 2006; 2009). 

The OSHA proposal for medical 

surveillance of employees exposed to 

respirable crystalline silica above the 

PEL for 30 or more days per year is more 

comprehensive than the ASTM 

recommendation. Both the OSHA 

proposal and the ASTM standard use 

exposure above the occupational 

exposure limit as the trigger for medical 

surveillance. However, the OSHA 

proposal is more protective than the 

ASTM standard because it calls for 

medical surveillance of workers 

exposed for a shorter duration of time. 

OSHA believes that the proposed 

cutoffs, based both on exposure level 

and on the number of days per year that 

an employee is exposed to respirable 

crystalline silica, are a reasonable and 

administratively convenient basis for 

providing medical surveillance benefits 

to respirable crystalline silica-exposed 

workers. With the exception of the 

asbestos standard (29 CFR 1910.1001), 

which doesn’t specify an action level, 

medical surveillance in OSHA 

standards such as chromium (VI) (29 

CFR 1910.1026), methylene chloride (29 

CFR 1910.1052), and cadmium (29 CFR 

1910.1027) is triggered by exposure at or 

above action level. However, OSHA 

notes that employees exposed at or 

below the PEL, or exposed above the 

PEL for only a few days in a year, will 

be at lower risk of developing respirable 

crystalline silica-related disease than 

employees who are exposed above the 

PEL for 30 or more days per year. 

Medical surveillance triggered by 

exposures above the PEL covers 

employees who face the highest risk of 

developing disease related to respirable 

crystalline silica exposure. OSHA 

estimates that approximately 351,000 

employees would be exposed above the 

proposed PEL for more than 30 days per 

year, and therefore require medical 

surveillance under the proposed 

standard. For comparison, OSHA 

estimates approximately 1,026,000 

employees would be exposed above the 

proposed action level of 25 ug/m3 but at 

or below the proposed PEL, a difference 

of 675,000 employees. The total number 

of medical exams required, which takes 

into account turnover in the work force, 

would be similarly affected. For 

example, in the first year following 

promulgation, approximately 454,000 

exams would be required under the 

proposed standard. If medical 

surveillance was triggered at the action 

level rather than the PEL, over 1,280,000 

exams would be required. Under the 

proposed standard, periodic medical 

exams would be required on a triennial 

basis, increasing over time the total 

number of medical exams. Thus, 

requiring medical surveillance only for 

employees exposed above the proposed 

PEL reduces the burden on employers 

and focuses resources on the employees 

at highest risk. OSHA solicits comments 

on the approporate trigger for medical 

surveillance in the issues section of the 

NPRM. 

Paragraph (h)(1)(ii) of the proposal 

requires that the medical examinations 

made available under the rule be 

performed by a physician or other 

licensed health care professional 

(PLHCP). The term ‘‘PLHCP,’’ as 

discussed further in section (b) 

(Definitions), above, refers to 

individuals whose legal scope of 

practice allows them to provide, or be 

delegated responsibility to provide, 

some or all of the health care services 

required by the medical surveillance 

provisions. The determination of who 

qualifies as a PLHCP is thus determined 

on a state-by-state basis. OSHA 

considers it appropriate to allow any 

professional to perform medical 

examinations and procedures made 

available under the standard when they 

are licensed by state law to do so. This 

provision provides flexibility to the 

employer, and reduces cost and 

compliance burdens. The proposed 

requirement is consistent with the 

approach of other recent OSHA 

standards, such as chromium (VI) (29 

CFR 1910.1026), methylene chloride (29 

CFR 1910.1052), and respiratory 

protection (29 CFR 1910.134). 

The proposed standard also specifies 

how frequently medical examinations 

are to be offered to those employees 

covered by the medical surveillance 

program. Under paragraph (h)(2), 

employers are required to make 

available to covered employees an 

initial (baseline) examination within 30 

days after initial assignment unless the 

employee has received a medical 

examination provided in accordance 

with the standard within the past three 

years. The proposed requirement that a 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56469 

medical examination be offered at the 

time of initial assignment is intended to 

determine if an individual will be able 

to work in the job involving respirable 

crystalline silica exposure without 

adverse effects. It also serves the useful 

function of establishing a health 

baseline for future reference. Where an 

examination that complies with the 

requirements of the standard has been 

provided in the past three years, that 

previous examination would serve these 

purposes, and an additional 

examination would not be needed. For 

example, some employees may work 

short-term jobs associated with 

construction projects and other 

activities of limited duration. In these 

circumstances, an employee may work 

for several different employers over the 

course of a three-year period. In such 

cases, each employer who hires the 

employee within three years of the 

employee’s last medical examination 

would not have to make available an 

initial medical examination, but could 

rely on a written medical opinion from 

an examination provided in the past 

three years, if the examination complied 

with the requirements of the standard. 

Proposed paragraphs (h)(2)(i)-(vi) 

specify that the baseline medical 

examination provided by the PLHCP 

must consist of: medical and work 

history; physical examination with 

special emphasis on the respiratory 

system; chest X-ray or equivalent 

diagnostic study; pulmonary function 

test; latent tuberculosis test; and other 

tests deemed appropriate by the PLHCP. 

Special emphasis is placed on the 

portions of the medical and work 

history focusing on exposure to 

respirable-crystalline silica or other 

agents affecting the respiratory system, 

history of respiratory system 

dysfunction (including signs and 

symptoms such as shortness of breath, 

coughing, and wheezing), history of 

tuberculosis, and smoking. 

Medical and work histories are 

required because they are an efficient 

and inexpensive means for collecting 

information that can aid in identifying 

individuals who are at risk because of 

hazardous exposures (ACOEM, 2006; 

WHO, 1996). Information on present 

and past work exposures, medical 

illnesses, and symptoms can lead to the 

detection of diseases at early stages 

when preventive measures can be taken. 

Recording of symptoms is important 

because, in some cases, symptoms 

indicating onset of disease can occur in 

the absence of abnormal laboratory test 

findings. 

The physical exam focuses on the 

respiratory system, which is known to 

be susceptible to respirable crystalline 

silica toxicity. Aspects of the physical 

exam, such as visual inspection, 

palpation, tapping, and listening with a 

stethoscope, would allow the PLHCP to 

detect abnormalities in chest shape or 

lung sounds that are associated with 

compromised lung function (WHO, 

1996; IMA/MSHA, 2008; NISA, 2010; 

ACOEM, 2006). The ASTM standards do 

not specifically address a physical exam 

as part of medical surveillance, but 

physical exams are included in other 

recommendations (IMA/MSHA, 2008; 

NISA, 2010; ACOEM, 2006; BCTD, 

2001). OSHA’s proposal for a physical 

exam provides for a more 

comprehensive medical evaluation than 

that required by the ASTM standards. 

OSHA proposes that an X-ray or an 

equivalent diagnostic study be made 

available at the first medical 

examination. An initial chest X-ray, 

although not useful for preventing 

silicosis, can be useful for diagnosing 

silicosis, for detecting mycobacterial 

disease, and for detecting large opacities 

associated with cancer (IMA/MSHA 

2008). It also provides baseline data 

upon which to assess any subsequent 

changes. X-rays are the standard 

medical test to diagnose respirable 

crystalline silica-related lung diseases. 

However, the proposal allows for an 

equivalent diagnostic study in place of 

the chest X-ray. This is intended to 

allow for use of technologically 

advanced imaging techniques in place 

of conventional X-rays. 

An example of a diagnostic study that 

is equivalent to an X-ray is a digital 

chest radiograph. Medical imaging is 

currently in the process of transitioning 

from conventional film-based 

radiography to digital radiography 

systems. Digital imaging systems offer a 

number of advantages over conventional 

film-based X-rays, including more 

consistent image quality, faster results, 

increased ability to share images with 

multiple readers, simplified storage of 

images, and reduced risk for technicians 

and the environment due to the 

elimination of chemicals for developing 

film (Attfield and Weissman, 2009). 

The proposed standard calls for an Xray size of no less than 14 x 17 inches 

and no more than 16 x17 inches at full 

inspiration, which is consistent with the 

X-ray film size required in NIOSH 

specifications for medical examination 

of underground coal miners (42 CFR 

part 37). The proposed standard also 

specifies interpretation and 

classification of X-rays according to the 

International Labour Organization (ILO) 

International Classification of 

Radiographs of Pneumoconioses by a 

NIOSH-certified ‘‘B’’ reader. The ILO 

recently made standard digital 

radiographic images available and has 

published guidelines on the 

interpretation and classification of 

digital radiographic images (ILO 2011). 

Therefore, digital radiographic images 

can now be evaluated according to the 

same ILO guidelines as X-ray films and 

are considered equivalent diagnostic 

tests. The ILO guidelines require that 

digital images be displayed on a 

medical-grade flat-panel monitor 

designed for diagnostic radiology. ILO 

specifications for those monitors 

include a minimal diagonal display of 

21 inches per image, a maximum to 

minimum luminance ratio of at least 50, 

a maximum luminance of no less than 

250 candelas per square meter, a pixel 

pitch not to exceed 210 mm, and a 

resolution no less than 2.5 line-pairs per 

millimeter. NIOSH (2011) has published 

guidelines for conducting digital 

radiography and displaying digital 

radiographic images in a manner that 

will allow for classification according to 

ILO guidelines. Hard copies printed 

from digital images are not 

recommended for classification because 

they give the appearance of more 

opacities compared to films or digital 

images (Franzblau et al., 2009). 

The ILO system was designed to 

assess X-ray and digital radiographic 

image quality and to describe 

radiographic findings of 

pneumoconiosis in a simple and 

reproducible way (NISA, 2010; WHO, 

1996; IMA/MSHA, 2008). The 

procedure involves scoring opacities 

according to shape, size, location, and 

profusion. Opacities are first classified 

as either small or large, with small 

opacities representing simple silicosis 

and large opacities representing 

complicated silicosis. The best indicator 

of silicosis severity is profusion, which 

is the B reader’s assessment of the 

amount of small opacities seen in the 

lung fields (NISA, 2010; IMA/MSHA, 

2008). Using a standard set of ILO X-ray 

films or digital radiographic images, the 

B reader compares the workers’ X-rays 

or digital radiographic images with the 

ILO films or digital radiographic images 

and rates the profusion of small 

opacities. The numbers 0, 1, 2, or 3 are 

used to indicate increasing amounts of 

small opacities. A 12-point profusion 

scale is employed, in which the B reader 

gives a first choice and then a second 

choice profusion rating. 

A NIOSH-certified B reader is a 

physician who has demonstrated 

competency in the ILO classification 

system by passing proficiency and 

periodic recertification examinations 

(NIOSH, 2011a). The NIOSH 

certification procedures were designed 

to improve the proficiency of X-ray and 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56470 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

digital radiographic image readers and 

minimize variability of readings. 

Standardized procedures for the 

evaluation of X-ray films and digital 

images by certified, qualified 

individuals is warranted by the 

prevalence and seriousness of silicosis. 

As of February 12, 2013, there were 242 

certified B readers in the United States. 

Other radiological test methods that 

may be useful are computed 

tomography (CT) or high resolution 

computed tomography (HRCT) scans. 

Two older studies reported that CT or 

HRCT scans were not more sensitive 

than X-rays for detecting silicosis but 

were more sensitive than X-rays at 

distinguishing between early and 

advanced stages of silicosis (Be ́gin et al., 

1987a; Talini et al., 1995). More recent 

studies and reviews reported that CT or 

HRCT may be superior to chest X-ray in 

the early detection of silicosis and the 

identification of progressive massive 

fibrosis (PMF) (Sun et al., 2008; Lopes 

et al., 2008; Blum et al., 2008). However, 

the value of CT or HRCT scans should 

be balanced with risks and 

disadvantages of those methods, which 

include higher radiation doses (WHO, 

1996). 

CT or HRCT scans could be 

considered ‘‘equivalent diagnostic 

studies’’ under paragraph (h)(2)(iii) of 

the proposed standard. However, 

standardized methods for interpreting 

and reporting the results of CT or HRCT 

scans are not currently available. The 

Agency seeks comment on whether CT 

and HRCT scans should be considered 

‘‘equivalent diagnostic studies’’ under 

the standard, and has included this 

topic in the ‘‘Issues’’ section of this 

preamble. 

Paragraph (h)(2)(iv) of the proposed 

OSHA standard calls for spirometry 

testing (forced vital capacity [FVC], 

forced expiratory volume at one second 

[FEV1], and FEV1/FVC ratio) by a 

spirometry technician with current 

certification from a NIOSH-approved 

spirometry course as part of the baseline 

medical examination. Pulmonary 

function tests, such as spirometry, are 

optional under the ASTM standards 

(ASTM, 2006; 2009). ASTM (2006, 

2009) and others point to a lack of 

evidence that routine spirometry testing 

is useful for detecting early stages of 

respirable crystalline silica-related 

disease. They indicate that most 

abnormalities detected by spirometry 

screening are not related to respirable 

crystalline silica-related diseases but 

rather to factors such as smoking and 

non-occupationally related diseases. 

There are also a number of obstacles to 

widespread use of spirometry including 

inadequate training of medical 

personnel, technical problems with 

some spirometers, and lack of 

standardization for testing 

methodologies and procedures 

(ACOEM, 2011; IMA/MSHA, 2008; 

ATS/ERS, 2005; NISA, 2010). However, 

ACOEM, (2011), IMA/MSHA (2008), 

American Thoracic Society/European 

Respiratory Society (ATS/ERS, 2005), 

and NISA (2010) go on to note that 

properly conducted spirometry is 

considered a useful part of respiratory 

medical surveillance programs. 

Because quality lung function tests 

are useful for obtaining information 

about the employee’s lung capacity and 

respiratory flow rate, OSHA proposes to 

require spirometry as part of the 

baseline medical examination. 

Information provided by spirometry is 

useful for determining baseline lung 

function status upon which to assess 

any subsequent lung function changes 

and for evaluating any loss of lung 

function. This information may also be 

useful in assessing the health of 

employees who wear respirators. The 

proposed requirement is consistent with 

the approach of other OSHA standards, 

such as those for asbestos (29 CFR 

1910.1001) and cadmium (29 CFR 

1910.1027). 

Because it is imperative that 

spirometry be conducted according to 

strict standards for quality control and 

for results to be consistently interpreted, 

OSHA proposes that spirometry be 

administered by a spirometry technician 

with current certification from a NIOSHapproved spirometry course. The 

NIOSH-approved spirometry training is 

based upon procedures and 

interpretation standards developed by 

the ATS/ERS and European Respiratory 

Society and addresses topics such as 

instrument calibration, testing 

performance, data quality, and 

interpretation of results (NIOSH, 2011b). 

Requiring spirometry technicians to 

have current certification from a 

NIOSH-approved spirometry course will 

improve their proficiency in generating 

quality results that are consistently 

interpreted. Similar recommendations 

are included in the ASTM standards 

(Section 4.6.5.4) (ASTM 2006; 2009). 

In paragraph (h)(2)(v), OSHA 

proposes testing for latent tuberculosis 

infection at the baseline medical 

examination. In contrast, the ASTM 

standards (Section 4.6.5.3) recommend 

tuberculosis testing only when an X-ray 

shows evidence of silicosis (ASTM, 

2006; 2009). NISA (2010) recommends 

baseline tuberculosis testing and 

periodic testing in workers who have 

chest X-ray readings of 1/0 or higher or 

more than 25 years of exposure to 

respirable crystalline silica. OSHA 

believes that a general requirement for 

testing during the initial medical 

examination will serve to protect 

workers exposed to respirable 

crystalline silica by identifying latent 

tuberculosis infection so it can be 

treated before active (infectious) 

tuberculosis develops. 

In 2008, there were almost 13,000 

new cases of active tuberculosis in the 

U.S. Although incidence of tuberculosis 

continues to decrease in the U.S., the 

ultimate goal of tuberculosis control and 

prevention in the U.S. is the elimination 

of tuberculosis (CDC, 2009). Active 

tuberculosis cases are prevented by 

identifying and treating those with 

latent tuberculosis disease. 

As described in OSHA’s Health 

Effects analysis and summarized in 

Section V of this preamble, the risk of 

developing active tuberculosis infection 

is higher in individuals with silicosis 

than those without silicosis (Balmes, 

1990; Cowie, 1994; Hnizdo and Murray, 

1998; Kleinschmidt and Churchyard, 

1997; Murray et al., 1996). Moreover, 

there is evidence that exposure to silica 

increases the risk for pulmonary 

tuberculosis, independent of the 

presence of silicosis (Cowie, 1994; 

Hnizdo and Murray, 1998; 

teWaterNaude et al., 2006). OSHA 

therefore preliminarily concludes that it 

is in the best interest of both the 

employer and the affected worker to 

identify latent tuberculosis prior to 

silica exposure. The increased risk of 

developing active pulmonary 

tuberculosis places not only the worker, 

but also his or her co-workers and 

family members at increased risk of 

acquiring this potentially fatal 

infectious disease. Early treatment of 

latent disease would eliminate this risk. 

Testing for latent tuberculosis infection 

will identify cases of this disease and 

alert affected workers, so that the 

necessary treatment can be obtained 

from their local public health 

department or other health care 

provider. OSHA’s proposed requirement 

is consistent with the recommendations 

of ACOEM (2006), which recommends 

tuberculosis screening for all silicaexposed workers. The Centers for 

Disease Control and Prevention 

recommends that tuberculosis testing 

target populations who are at the 

highest risk of developing the disease, 

including those with silicosis (CDC, 

2000). The Agency seeks comment on 

its preliminary determination that all 

workers receiving an initial medical 

exam should receive testing for latent 

tuberculosis infection, and has included 

this topic in the ‘‘Issues’’ section of this 

preamble. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56471 

Paragraph (h)(2)(vi) of the proposal 

gives the examining PLHCP the 

flexibility to determine additional tests 

deemed to be appropriate. While the 

tests conducted under this section are 

for screening purposes, diagnostic tests 

may be necessary to address a specific 

medical complaint or finding (IMA/

MSHA, 2008). For example, the PLHCP 

may decide that additional tests are 

needed to address abnormal findings in 

a pulmonary function test. OSHA 

believes that the PLHCP is in the best 

position to decide if any additional 

medical tests are necessary for each 

individual examined. Where additional 

tests are deemed appropriate by the 

PLHCP, the proposed standard would 

require that they be made available. 

In paragraph (h)(3)(i), OSHA proposes 

periodic examinations including 

medical and work history, physical 

examination emphasizing the 

respiratory system, chest X-rays and 

pulmonary function tests, and other 

tests deemed to be appropriate by the 

PLHCP. The examinations would be 

required every three years under 

paragraph (h)(3) of this proposal, unless 

the PLHCP recommends that they be 

made available more frequently. The 

specific requirements for the 

examinations and the value of the 

examinations for screening workers 

exposed to respirable crystalline silica 

were addressed above. The proposed 

requirement for examinations every 

three years is consistent with the ASTM 

standards (Section 4.6.5), which 

recommend that medical surveillance be 

conducted no less than every three years 

(ASTM, 2006; 2009). Other standards 

recommend periodic evaluations at 

intervals ranging from two to five years, 

depending on duration of exposure 

(IMA/MSHA, 2008; NISA, 2010; 

ACOEM, 2006; BCTD, 2001). 

The main goal of periodic medical 

surveillance for workers is to detect 

adverse health effects at an early and 

potentially reversible stage. Based on 

the Agency’s experience, OSHA believes 

that surveillance every three years 

would strike a reasonable balance 

between the need to diagnose health 

effects at an early stage and the limited 

number of cases likely to be identified 

through surveillance. 

The proposed requirement that 

employers offer a chest X-ray or an 

equivalent diagnostic test as part of the 

periodic medical examination 

conducted every three years is an 

important aspect of early disease 

detection. As indicated above, X-rays 

are appropriate tools for detecting and 

monitoring the progression of silicosis, 

possible complications such as 

mycobacterial disease, and large 

opacities related to cancer (IMA/MSHA 

2008). Detection of simple silicosis by 

periodic X-ray could allow for 

implementation of exposure reduction 

methods that are likely to decrease the 

risk of disease progression (ACOEM, 

2006). X-rays would also allow the 

detection of treatable conditions, such 

as mycobacterial infections (ACOEM, 

2006). 

X-rays conducted every three years as 

part of the triennial medical 

examinations are appropriate 

considering the long latency period of 

most respirable crystalline silica-related 

diseases. The proposed three-year 

frequency for chest X-rays represents a 

simplified approach that balances a 

reasonable time frame for detecting 

disease and administrative convenience. 

Under paragraph (h)(3)(ii) of the 

proposed standard, the PLHCP can 

request X-rays more frequently. The 

proposed frequency is consistent with 

the ASTM standards, as well as ACOEM 

recommendations (ASTM, 2006; 2009; 

ACOEM, 2006). Other groups 

recommend X-rays at intervals ranging 

from every two to five years, depending 

on exposure duration (IMA/MSHA, 

2008; NISA, 2010; WHO, 1996). OSHA 

is interested in comments on the 

proposed X-ray frequency and has 

raised this topic in the ‘‘Issues’’ section 

of this preamble. 

Proposed paragraph (h)(3) also 

requires that spirometry (FVC, FEV1, 

and FEV1/FVC ratio) be offered by a 

spirometry technician with current 

certification from a NIOSH-approved 

spirometry course, as part of the 

medical examination conducted every 

three years. As noted above, spirometry 

is optional in the ASTM standards 

(ASTM, 2006; 2009). However, OSHA 

believes that periodic spirometry is a 

potentially valuable tool for detecting 

respirable crystalline silica-related 

disease and monitoring the health of 

exposed workers. 

Periodic spirometry that adheres to 

strict quality standards is useful for 

monitoring progressive lung function 

changes to identify individual workers 

or groups of workers with abnormal 

lung function changes. Quality 

longitudinal spirometry testing that 

compares workers’ lung function to 

their baseline levels is useful for 

detecting excessive declines in lung 

function that could lead to severe 

impairment over time. For example, 

recent studies have shown that 

excessive decline in lung function can 

be an early warning sign for risk of 

COPD development (Wang et al., 2009). 

Identifying workers who are at risk of 

developing severe decrements in lung 

function would allow for interventions 

to prevent further progression of 

disease. OSHA is proposing a medical 

examination including a lung function 

test every three years because exposure 

to respirable crystalline silica does not 

usually cause severe declines in lung 

function over short time periods. The 

proposed frequency is consistent with 

ACOEM (2006) and BCTD (2001), which 

recommend lung function testing every 

two to three years. WHO (1996) and 

NISA (2010) recommend annual 

pulmonary function testing, but WHO 

(1996) states that if this is not feasible, 

it can be conducted at the same 

frequency as chest X-rays (every two to 

five years). Paragraph (h)(3) of the 

proposed standard gives the PLHCP the 

authority to request lung function 

testing more frequently. The PLHCP 

might recommend such a test because of 

age, tenure, exposure level, or abnormal 

results. The Agency seeks comment on 

the proposed frequency of pulmonary 

function testing and has raised this 

topic in the ‘‘Issues’’ section of this 

preamble. 

Paragraph (h)(4) of the proposed 

standard would require the employer to 

ensure the examining PLHCP has a copy 

of the standard, and to provide the 

following information to the PLHCP: a 

description of the affected employee’s 

former, current, and anticipated duties 

as they relate to respirable crystalline 

silica exposure; the employee’s former, 

current, and anticipated exposure level; 

a description of any personal protective 

equipment used or to be used by the 

employee, including when and for how 

long the employee has used that 

equipment; and information from 

records of employment-related medical 

examinations previously provided to the 

affected employee and currently within 

the control of the employer. Making this 

information available to the PLHCP will 

aid in the evaluation of the employee’s 

health in relation to assigned duties and 

fitness to use personal protective 

equipment, when necessary. The results 

of exposure monitoring are part of the 

information that would be supplied to 

the PLHCP responsible for medical 

surveillance. These results contribute 

valuable information to assist the 

PLHCP in determining if an employee is 

likely to be at risk of harmful effects 

from respirable crystalline silica 

exposure. A well-documented exposure 

history also assists the PLHCP in 

determining if a condition (e.g., 

compromised pulmonary function) may 

be related to respirable crystalline silica 

exposure. Where the employer does not 

have information directly indicating an 

employee’s exposure (e.g., where the 

employer uses Table 1 in the proposed 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56472 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

construction standard and does not 

perform exposure monitoring), an 

indication of the presumed exposure 

associated with the operation (i.e., at or 

above the action level, above the PEL) 

would fulfill this requirement. 

Proposed paragraph (h)(5)(i) requires 

that the employer obtain a written 

medical opinion from the PLHCP within 

30 days of each medical examination. 

The purpose of this requirement is to 

provide the employer with a medical 

basis to aid in the determination of 

placement of employees and to assess 

the employee’s ability to use protective 

clothing and equipment. OSHA believes 

the 30-day period will provide the 

PLHCP sufficient time to receive and 

consider the results of any tests 

included in the examination, and allow 

the employer to take any necessary 

protective measures in a timely manner. 

The proposed requirement that the 

opinion be in written form is intended 

to ensure that employers and employees 

receive the benefit of this information. 

Paragraphs (h)(5)(i)(A)–(D) of the 

proposal specify what must be included 

in the PLHCP’s opinion. The standard 

first proposes that the PLHCP’s written 

medical opinion describe the 

employee’s health condition as it relates 

to exposure to respirable crystalline 

silica, including any conditions that 

would put the employee at increased 

risk of material impairment of health 

from further exposure to respirable 

crystalline silica. The standard also 

proposes that the PLHCP’s written 

medical opinion include recommended 

limitations for the employee’s exposure 

to respirable crystalline silica or use of 

personal protective equipment such as 

respirators. These proposed 

requirements are consistent with the 

overall goals of medical surveillance: to 

determine if an individual can be 

exposed to respirable crystalline silica 

present in his or her workplace without 

experiencing adverse health effects, to 

identify respirable crystalline silicarelated adverse health effects so that 

appropriate intervention measures can 

be taken, and to determine the 

employee’s fitness to use personal 

protective equipment such as 

respirators. 

Paragraph (h)(5)(i)(C) proposes that 

the PLHCP must include in the written 

medical opinion a statement that the 

employee should be examined by a 

pulmonary specialist if the X-ray is 

classified as 1/0 or higher by the ‘‘B’’ 

reader, or if referral to a pulmonary 

specialist is otherwise deemed 

appropriate by the PLHCP. As described 

above, paragraph (h)(2)(iii) of the 

proposed standard requires that X-rays 

be interpreted according to the ILO 

Classification of Radiographs of 

Pneumoconioses. The ASTM standards 

recommend that workers with profusion 

opacities greater than 1/1 (profusion 

similar to that shown on a standard 

category 1 radiograph) be evaluated at a 

frequency determined by a physician 

qualified in pulmonary disease (Section 

4.7.1) and receive annual counseling by 

a physician or other person 

knowledgeable in occupational safety 

and health (Section 4.7.2) (ASTM, 2006; 

2009). The proposed OSHA standard 

addresses pneumoconiosis at an earlier 

stage than the ASTM standards, thus 

allowing for intervention at an earlier 

indication of possibly abnormal 

findings. 

Paragraph (h)(5)(i)(D) of the proposal 

would require that the PLHCP include 

in the written medical opinion a 

statement that the PLHCP has explained 

to the employee the medical 

examination results, including 

conditions related to respirable 

crystalline silica exposure that require 

further evaluation or treatment and any 

recommendations related to use of 

protective clothing or equipment. Under 

this provision, OSHA anticipates that 

the employee will be informed directly 

by the PLHCP of all results of his or her 

medical examination, including 

conditions of nonoccupational origin. 

Direct consultation between the PLHCP 

and employee ensures that the 

employee will receive all information 

about health status, including nonoccupationally related conditions, that 

are not communicated to the employer. 

Under proposed paragraph (h)(5)(ii), 

the employer must ensure that the 

PLHCP does not include findings 

unrelated to crystalline silica exposure 

in the written opinion provided to the 

employer or otherwise reveal such 

findings to the employer. OSHA has 

proposed this provision to ensure 

confidentiality of medical information 

and to reassure employees participating 

in medical surveillance that they will 

not be penalized or embarrassed as a 

result of the employer obtaining 

information about them not directly 

pertinent to occupational exposure to 

respirable crystalline silica. Paragraph 

(h)(5)(iii) of the proposed standard 

requires the employer to provide a copy 

of the PLHCP’s written opinion to the 

employee within two weeks after the 

employer receives it, to ensure that the 

employee has been informed of the 

results of the examination in a timely 

manner. 

OSHA is aware of concerns that the 

written medical opinion may divulge 

confidential information regarding an 

employee’s medical condition, or may 

otherwise divulge information that may 

adversely affect an individual’s 

employment status. The Building and 

Construction Trades Department, AFL– 

CIO has expressed the view that, except 

in limited circumstances, any decision 

to disclose medical information to an 

employer should be left to the employee 

(BCTD, 2009). OSHA respects concerns 

for medical privacy and is aware of how 

disclosure of medical information could 

potentially impact workers. The 

proposed requirements are intended to 

balance employee privacy with 

employers’ need for information to 

assess possible health effects or risks 

related to respirable crystalline silica 

exposure by employees. OSHA seeks 

comment on the proposed requirement 

for the employer to obtain a written 

medical opinion, and has raised this 

topic in the ‘‘Issues’’ section of this 

preamble. 

Proposed paragraph (h)(6)(i) requires 

that an examination by a pulmonary 

specialist be offered when indicated in 

the PLHCP’s written opinion. This 

requirement is intended to ensure that 

individuals with abnormal findings are 

seen by a professional with expertise in 

respiratory disease who can provide not 

only expert medical judgment, but also 

counseling regarding work practices and 

personal habits that could affect these 

individuals’ respiratory health. In this 

respect the proposed provision is 

conceptually consistent with the 

provision in the ASTM standards (4.7.2) 

for counseling by a physician or other 

person qualified in occupational safety 

and health. Data presented by the 

American Board of Internal Medicine 

(ABIM) indicate that as of February 5, 

2013, 13,138 physicians in the United 

States had valid certificates in 

pulmonary disease (ABIM, 2013). ABIM 

does not report how many of these 

physicians are currently practicing. 

However, ABIM does report that 4,378 

new certificates in pulmonary disease 

were issued in the period from 2001– 

20010 (ABIM, 2012). Because 

physicians are likely to practice in the 

field for some time after receiving their 

certification, this figure indicates that a 

substantial number of pulmonary 

specialists are available to perform 

examinations required under the 

proposed standard. 

Paragraph (h)(6)(i) further proposes 

that these additional examinations by 

pulmonary specialists must be made 

available within 30 days following 

receipt of the PLHCP’s recommendation 

that examination by such a specialist is 

indicated. OSHA proposes, under 

paragraph (h)(6)(ii), that the employer 

provide the pulmonary specialist with 

the same information that is provided to 

the original PLHCP (i.e., a copy of the 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56473 

standard; a description of the affected 

employee’s former, current, and 

anticipated duties as they relate to 

respirable crystalline silica exposure; 

the employee’s former, current, and 

anticipated exposure level; a description 

of any personal protective equipment 

used or to be used by the employee, 

including when and for how long the 

employee has used that equipment; and 

information from records of 

employment-related medical 

examinations previously provided to the 

affected employee, currently within the 

control of the employer). The reasons 

why the pulmonary specialist should 

receive this information are the same as 

those for the PLHCP and were addressed 

above. 

Proposed paragraph (h)(6)(iii) requires 

the employer to obtain a written 

medical opinion from the pulmonary 

specialist comparable to the written 

opinion obtained from the original 

PLHCP, including a description of the 

employee’s health condition as it relates 

to respirable crystalline silica exposure, 

the pulmonary specialist’s opinion as to 

whether the employee would be placed 

at increased risk of material health 

impairment as a result of exposure to 

respirable crystalline silica, and any 

recommended limitations on the 

employee’s exposure to respirable 

crystalline silica or use of personal 

protective equipment. The pulmonary 

specialist would also need to state in the 

written opinion that these findings were 

explained to the employee. The reasons 

why the pulmonary specialist should 

provide this information to the 

employer are the same as those for the 

PLHCP and were addressed above. 

Some OSHA health standards contain 

a provision for medical removal 

protection (MRP). MRP typically 

requires that the employer temporarily 

remove an employee from exposure 

when such an action is recommended in 

a written medical opinion. During the 

time of removal, the employer is 

required to maintain the total normal 

earnings, as well as all other employee 

rights and benefits, of the removed 

employee. However, MRP is not 

intended to serve as a workers’ 

compensation system. The primary 

reason MRP was included in previous 

standards was to encourage employee 

participation in medical surveillance. 

By protecting employees who are 

removed on a temporary basis from 

economic loss, this potential 

disincentive to participating in medical 

surveillance is alleviated. Previous 

standards also included MRP 

requirements to prevent the onset of 

disease and to detect and minimize the 

extent of existing disease. For example, 

OSHA’s cadmium standard (29 CFR 

1910.1026) provides for MRP based on 

criteria such as biological monitoring 

results and evidence of cadmiumrelated disease. Removal from exposure 

can allow for biological monitoring 

results to return to acceptable levels, or 

for improvement in the employee’s 

health condition. 

OSHA has made a preliminary 

determination that MRP is not 

reasonably necessary or appropriate for 

respirable crystalline silica-related 

health effects. Thus, the proposed rule 

does not include a provision for MRP. 

The Agency believes that respirable 

crystalline silica-related health effects 

(e.g., silicosis) are generally chronic 

conditions that are not remedied by 

temporary removal from exposure. 

Since situations where temporary 

removal would be appropriate are not 

anticipated to occur, OSHA does not 

believe that MRP is necessary. The 

Agency seeks comment on this 

preliminary determination, and has 

included this topic in the ‘‘Issues’’ 

section of this preamble. 

(i) Communication of Respirable 

Crystalline Silica Hazards to Employees 

The proposed standard includes 

requirements intended to ensure that 

the dangers of respirable crystalline 

silica exposure are communicated to 

employees by means of labels, safety 

data sheets, and employee information 

and training. OSHA believes that it is 

necessary to inform employees of the 

hazards to which they are exposed, 

along with associated protective 

measures, so that employees understand 

how they can minimize potential health 

hazards. As part of an overall hazard 

communication program, training serves 

to explain and reinforce the information 

presented on labels and in safety data 

sheets. These written forms of 

communication will be effective and 

relevant only when employees 

understand the information presented 

and are aware of the actions to be taken 

to avoid or minimize exposures, thereby 

reducing the possibility of experiencing 

adverse health effects. 

OSHA has proposed to revise its 

existing hazard communication 

standard (HCS) (29 CFR 1910.1200) to 

conform with the United Nations’ 

Globally Harmonized System of 

Classification and Labelling of 

Chemicals (GHS), Revision 3. (See 74 FR 

50280, Sept. 30, 2009.) The hazard 

communication requirements of the 

proposed crystalline silica rule are 

designed to be consistent with the 

revised HCS, while including additional 

specific requirements needed to protect 

employees exposed to respirable 

crystalline silica. OSHA intends for the 

requirements of the respirable 

crystalline silica rule to conform with 

the final hazard communication 

standard. The proposed requirements 

are also consistent with the worker 

training and education provisions of 

ASTM International’s standards 

addressing control of occupational 

exposure to respirable crystalline silica 

(Section 4.8 in both E 1132–06 and E 

2625–09) (ASTM, 2006; 2009). 

In the HCS rulemaking, OSHA 

proposed to revise substance-specific 

health standards by referencing the HCS 

requirements for labels, safety data 

sheets, and training and by identifying 

the hazards that need to be addressed in 

the employer’s written hazard 

communication program. Accordingly, 

proposed paragraph (i)(1) of the silica 

rule requires compliance with the HCS 

requirements and lists cancer, lung 

effects, immune system effects, and 

kidney effects as hazards that need to be 

addressed in the employer’s hazard 

communication program. These are the 

health effects that OSHA has 

preliminarily determined to be 

associated with respirable crystalline 

silica exposure. 

Proposed paragraph (i)(2)(i) requires 

the employer to ensure that each 

affected employee can demonstrate 

knowledge of the specified training 

elements (discussed below). When using 

the term ‘‘affected employee’’ in this 

context, OSHA is referring to any 

employee who may be exposed to 

respirable crystalline silica under 

normal conditions of use or in a 

foreseeable emergency. Employee 

knowledge of the specified training 

elements could be determined through 

methods such as discussion of the 

required training subjects, written tests, 

or oral quizzes. In order to ensure that 

employees comprehend the material 

presented during training, it is critical 

that trainees have the opportunity to ask 

questions and receive answers if they do 

not fully understand the material that is 

presented to them. When videotape 

presentations or computer-based 

programs are used, this requirement 

may be met by having a qualified trainer 

available to address questions after the 

presentation, or providing a telephone 

hotline so that trainees will have direct 

access to a qualified trainer. 

Proposed paragraphs (i)(2)(i)(A) and 

(B), which require training on specific 

operations in the workplace that could 

result in respirable crystalline silica 

exposure and specific procedures the 

employer has implemented to protect 

employees from exposure to respirable 

crystalline silica, closely parallel the 

HCS. OSHA has included these 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56474 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

elements in the proposed respirable 

crystalline silica rule to ensure that both 

employers and employees understand 

the sources of potential silica exposure 

and control measures used to reduce 

exposure. Workers have a particularly 

important role in controlling silica 

exposures because work practices often 

play a crucial role in controlling 

exposures, and engineering controls 

frequently require action on the part of 

workers to function effectively. For 

example, stationary masonry saws using 

wet methods to control dust may require 

adjustment of the nozzle and the water 

flow rate to ensure that an adequate 

volume of water reaches the cutting 

area. Water filters may need to be rinsed 

or replaced at regular intervals, and 

basin water may need to be replaced on 

a regular basis to prevent clogging of the 

nozzles. Similarly, the effectiveness of 

local exhaust ventilation systems, 

another common method used to 

control exposures to respirable 

crystalline silica, is often enhanced by 

the use of proper work practices. When 

tuckpointing, for instance, workers 

should ensure that the shroud 

surrounding the grinding wheel remains 

flush against the working surface to 

minimize the amount of dust that 

escapes from the collection system. 

Operating the grinder in one direction 

(counter to the direction of blade 

rotation) is effective in directing mortar 

debris into the exhaust system, and 

backing the blade off before removing it 

from the slot permits the exhaust system 

to clear accumulated dust. Workers’ 

implementation of work practices such 

as these is often necessary to ensure that 

they are adequately protected, and 

OSHA has preliminarily concluded that 

the importance of recognizing potential 

exposures and understanding 

appropriate work practices merits 

including these provisions in the 

proposed silica rule. 

Proposed paragraph (i)(2)(i)(C) 

requires training on the contents of the 

respirable crystalline silica rule, and 

proposed paragraph (i)(2)(ii) requires 

that the employer make a copy of the 

standard readily available to employees 

without cost. OSHA believes that it is 

important for employees to be familiar 

with and have access to the proposed 

respirable crystalline silica standard and 

the employer’s obligations to comply 

with it. 

Proposed paragraph (i)(2)(i)(D) 

requires employers to provide training 

to workers on the purpose and 

description of the medical surveillance 

program found at paragraph (h) of the 

proposed silica rule. Such training 

should cover the signs and symptoms of 

respirable crystalline silica-related 

adverse health effects including cancer, 

lung effects, immune system effects, and 

kidney effects. This information will 

help to ensure that employees are able 

to effectively participate in medical 

surveillance, which is discussed above 

in section (h) (Medical surveillance). 

OSHA intends for the training 

requirements under the proposed silica 

standard, like those in the hazard 

communication standard, to be 

performance-oriented. The Agency has 

therefore written proposed section (i) in 

terms of objectives, which are meant to 

ensure that employees are made aware 

of the hazards associated with respirable 

crystalline silica in their workplace and 

how they can help to protect 

themselves. The proposed standard also 

lists the subjects, which are in addition 

to or reiterate those covered by the HCS, 

that must be addressed in training, but 

not the specific ways in which the 

training is to be accomplished. OSHA 

believes that the employer is in the best 

position to determine how the training 

can most effectively be accomplished. 

Hands-on training, videotapes, slide 

presentations, classroom instruction, 

informal discussions during safety 

meetings, written materials, or any 

combination of these methods may be 

appropriate. Such performance-oriented 

requirements are intended to encourage 

employers to tailor training to the needs 

of their workplaces, thereby resulting in 

the most effective training program in 

each specific workplace. 

In order for the training to be 

effective, the employer must ensure that 

it is provided in a manner that the 

employee is able to understand. OSHA 

has consistently required that employee 

training required by OSHA standards be 

presented in a manner that employees 

can understand. This position was 

recently reiterated in a memorandum to 

OSHA Regional Administrators from 

Assistant Secretary David Michaels 

(OSHA, 2010). Employees have varying 

educational levels, literacy, and 

language skills, and the training must be 

presented in a language, or languages, 

and at a level of understanding that 

accounts for these differences in order 

to meet the proposed requirement in 

paragraph (i)(2) that individuals being 

trained understand the specified 

elements. This may mean, for example, 

providing materials, instruction, or 

assistance in Spanish rather than 

English if the workers being trained are 

Spanish-speaking and do not 

understand English. The employer is 

not required to provide training in the 

employee’s preferred language if the 

employee understands both languages; 

as long as the employee is able to 

understand the material in the language 

used, the intent of the proposed 

standard would be met. 

The frequency of training under the 

proposed standard is determined by the 

needs of the workplace. At the time of 

initial assignment to a position 

involving exposure to respirable 

crystalline silica, each employee needs 

to be trained sufficiently to understand 

the specified training elements. 

Additional training may be needed 

periodically to refresh and reinforce the 

memories of employees who have 

previously been trained or to ensure that 

employees are informed of new 

developments in the workplace that 

may result in new or additional 

exposures to respirable crystalline 

silica. Additional training might also be 

necessary after new engineering controls 

are installed to ensure that employees 

are able to properly use the new 

controls and implement work practices 

relating to those controls. Further, 

employees might need additional 

training in the use of new personal 

protective equipment. Such training 

would ensure that employees are able to 

actively participate in protecting 

themselves under the conditions found 

in the workplace, even if those 

conditions change. 

(j) Recordkeeping 

Paragraph (j) of the proposed standard 

requires employers to maintain air 

monitoring data, objective data, and 

medical surveillance records. The 

recordkeeping requirements are 

proposed in accordance with section 

8(c) of the OSH Act (29 U.S.C. 657(c)), 

which authorizes OSHA to require 

employers to keep and make available 

records as necessary or appropriate for 

the enforcement of the Act or for 

developing information regarding the 

causes and prevention of occupational 

accidents and illnesses. 

Proposed paragraph (j)(1)(i) requires 

employers to keep accurate records of 

all air monitoring results used or relied 

on to assess employee exposure to 

respirable crystalline silica. Paragraph 

(j)(1)(ii) requires that such records 

include the following information: the 

date of measurement for each sample 

taken; the operation monitored; 

sampling and analytical methods used; 

the number, duration, and results of 

samples taken; the identity of the 

laboratory that performed the analysis; 

the type of personal protective 

equipment, such as respirators, worn by 

the employees monitored; and the 

name, social security number, and job 

classification of all employees 

represented by the monitoring, 

indicating which employees were 

actually monitored. These requirements 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56475 

are generally consistent with those 

found in other OSHA standards, such as 

methylene chloride (29 CFR 1910.1052) 

and chromium (VI) (29 CFR 1910.1026). 

OSHA has proposed an additional 

requirement in this rulemaking— 

recording the identity of the laboratory 

that performed the analysis of exposure 

measurements—because of the 

importance of ensuring that laboratories 

performing analyses of respirable 

crystalline silica samples conform with 

the requirements specified in paragraph 

(d)(5) of the proposed rule. 

Proposed paragraph (j)(2)(i) requires 

employers who rely on objective data, 

pursuant to proposed paragraph 

(d)(2)(ii)(B) or (d)(3)(ii), to keep accurate 

records of the objective data. Objective 

data means information, such as air 

monitoring data from industry-wide 

surveys or calculations based on the 

composition or chemical and physical 

properties of a substance, demonstrating 

employee exposure to respirable 

crystalline silica associated with a 

particular product, material, process, 

operation, or activity. 

Proposed paragraph (j)(2)(ii) requires 

the record to include: the crystalline 

silica-containing material in question; 

the source of the objective data; the 

testing protocol and results of testing; a 

description of the process, operation, or 

activity involved and how the data 

support the assessment; and other data 

relevant to the process, operation, 

activity, material, or employee 

exposures. Since objective data may be 

used to exempt the employer from 

provisions of the proposal or provide a 

basis for selection of respirators, it is 

critical that the use of objective data be 

carefully documented. Reliance on 

objective data is intended to provide the 

same degree of assurance that employee 

exposures have been correctly 

characterized as air monitoring would. 

The records should demonstrate a 

reasonable basis for the conclusions 

drawn from the objective data. 

Proposed paragraph (j)(3)(i) requires 

the employer to establish and maintain 

an accurate record for each employee 

subject to medical surveillance under 

paragraph (h) of the proposed standard. 

Paragraph (j)(3)(ii) lists the categories of 

information that an employer would be 

required to record: the name and social 

security number of the employee; a copy 

of the PLHCP’s and pulmonary 

specialist’s written opinions about the 

employee; and a copy of the information 

provided to the PLHCPs and pulmonary 

specialists as required by proposed 

paragraph (h)(4). The information 

provided to the PLHCPs and pulmonary 

specialists includes the employee’s 

duties as they relate to crystalline silica 

exposure, crystalline silica exposure 

levels, descriptions of personal 

protective equipment used by the 

employee, and information from 

employment-related medical 

examinations previously provided to the 

employee (see paragraph (h)(4)). 

OSHA believes that medical 

surveillance records, like exposure 

records, are necessary and appropriate 

for protection of employee health, 

enforcement of the standard, and 

development of information regarding 

the causes and prevention of 

occupational illnesses. Employee access 

to medical surveillance records helps 

protect employees because such records 

contribute to the evaluation of 

employees’ health and enable 

employees and their health care 

providers to make informed health care 

decisions. These records are especially 

important when an employee’s medical 

conditions place him or her at increased 

risk of health impairment from further 

exposure to respirable crystalline silica. 

Furthermore, the employer could 

evaluate medical surveillance data for 

indications that workplace conditions 

are associated with increased risk of 

illness and take corrective actions. 

Finally, the records can be used by the 

Agency and others to identify illnesses 

and deaths that may be attributable to 

respirable crystalline silica exposure, 

evaluate compliance programs, and 

assess the efficacy of the standard. 

Proposed paragraphs (j)(1)(iii), 

(j)(2)(iii), and (j)(3)(iii) require 

employers to maintain and provide 

access to air monitoring, objective data, 

and medical surveillance records, 

respectively, in accordance with 

OSHA’s standard addressing access to 

employee exposure and medical records 

(29 CFR 1910.1020). That standard, 

specifically 29 CFR 1910.1020(d), 

requires employers to ensure the 

preservation and retention of exposure 

and medical records. Air monitoring 

data and objective data are considered 

employee exposure records that must be 

maintained for at least 30 years in 

accordance with 29 CFR 

1910.1020(d)(1)(ii). Medical records 

must be maintained for at least the 

duration of employment plus 30 years 

in accordance with 29 CFR 

1910.1020(d)(1)(i). 

The maintenance and access 

provisions incorporated from 29 CFR 

1910.1020 ensure that records are 

available to employees so that they may 

examine the employer’s exposure 

assessments and assure themselves that 

they are being adequately protected. 

Moreover, compliance with the 

requirement to maintain records of 

exposure data will enable the employer 

to show, at least for the duration of the 

retention-of-records period, that the 

exposure assessment was accurate and 

conducted in an appropriate manner. 

The lengthy record retention period is 

necessitated in this case by the long 

latency period commonly associated 

with silica-related diseases. 

Furthermore, determining causality of 

disease in employees is assisted by, and 

in some cases requires, examining 

present and past exposure data as well 

as the results of present and past 

medical examinations. 

(k) Dates 

Under paragraph (k)(1) of the 

proposed standard, the final crystalline 

silica rule becomes effective 60 days 

after its publication in the Federal 

Register. This period is intended to 

allow affected employers the 

opportunity to familiarize themselves 

with the standard. Under paragraph 

(k)(2)(i), employer obligations to comply 

with most requirements of the final rule 

begin 180 days after the effective date 

(240 days after publication of the final 

rule). This additional time period after 

the effective date is designed to allow 

employers to complete initial exposure 

assessments, establish regulated areas or 

access control plans, provide initial 

medical examinations, and comply with 

other provisions of the rule. 

Paragraph (k)(2)(ii) allows additional 

time for employers to implement the 

engineering controls required under 

paragraph (f) of the proposed rule. 

Engineering controls need to be in place 

within one year after the effective date. 

This is to allow affected employers 

sufficient time to design, obtain, and 

install the necessary control equipment. 

During the period before engineering 

controls are implemented, employers 

must provide respiratory protection to 

employees under proposed paragraph 

(g)(1)(i). 

Paragraph (k)(2)(iii) specifies that the 

laboratory requirements in paragraph 

(d)(5)(ii) of this section commence two 

years after the effective date. OSHA 

recognizes that the requirements for 

monitoring in the proposed rule will 

increase the demand for analysis of 

respirable crystalline silica samples. A 

two year start-up period is proposed to 

allow time for laboratories to achieve 

compliance with the proposed 

requirements, particularly with regard 

to requirements for accreditation and 

round robin testing. 

OSHA solicits comment on the 

adequacy of these proposed start-up 

dates. OSHA would like to ensure that 

engineering controls and medical 

surveillance are implemented as quickly 

as possible, while also ensuring that 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56476 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

employers have sufficient time to 

complete these processes. OSHA is also 

interested in ensuring that laboratories 

comply with the requirements of the 

standard as quickly as possible, while 

also ensuring that sufficient laboratory 

capacity is available to meet the needs 

of employers. In addition, the Agency is 

interested in mitigating impacts on 

firms complying with the rule, and 

seeks comment on approaches that 

would phase in requirements of the rule 

based on industry, employer size, or 

other factors. The Agency has included 

these topics in the ‘‘Issues’’ section of 

this preamble. 

XVII. References 

[ABIM] American Board of Internal 

Medicine. (2012). Number of Candidates 

Certified Annually by the American 

Board of Internal Medicine. http:// 

www.abim.org/pdf/data-candidatescertified/Number-Certified-Annually.pdf 

OSHA–2010–0034–1488 

[ABIM] American Board of Internal 

Medicine. (2013). Candidates Certified— 

All Candidates. http://www.abim.org/

pdf/data-candidates-certified/allcandidates.pdf OSHA–2010–0034–1502 

[ACCSH] Advisory Committee On 

Construction Safety And Health (2009). 

Minutes of 10–11 December 2009 

Meeting. OSHA–2010–0034–1500 

[ACGIH] American Conference of 

Governmental Industrial Hygienists. 

(2001). Silica, Crystalline—Quartz. In: 

Documentation of the Threshold Limit 

Values and Biological Exposure Indices. 

7th ed. Cincinnati, p. 1–9. OSHA–2010– 

0034–0515 

[ACGIH] American Conference of 

Governmental Industrial Hygienists. 

(2010). Silica Crystalline, a-Quartz and 

Cristobalite. In: Documentation of the 

Threshold Limit Values and Biological 

Exposure Indices. Cincinnati, p. 1–18. 

OSHA–2010–0034–1503 

[ACOEM] American College of Occupational 

and Environmental Medicine. (2006). 

Medical Surveillance of Workers 

Exposed to Crystalline Silica. OSHA– 

2010–0034–1505 

[ACOEM] American College of Occupational 

and Environmental Medicine. (2011). 

ACOEM Guidance Statement. 

Spirometry in the Occupational Health 

Setting—2011 Update. http:// 

www.acoem.org/uploadedFiles/Public_

Affairs/Policies_And_Position_

Statements/ACOEM%

20Spirometry%20Statement.pdf OSHA– 

2010–0034–1506 

Aldy, J.E., and W.K. Viscusi, 2007. Age 

Differences in the Value of Statistical 

Life, Discussion Paper RFF DP 07005, 

Resources for the Future, April 2007. 

OSHA–2010–0034–1522 

Archer JD, Cooper GS, Reist PC, Storm JF, 

Nylander-French LA. (2002) Exposure to 

respirable crystalline silica in eastern 

North Carolina farm workers. AIHA J 

63(6):750–5. As cited in Swanepoel et al. 

(2010). OSHA–2010–0034–1491 

[ASTM] ASTM International. (2006). 

Standard Practice for Health 

Requirements Relating to Occupational 

Exposure to Respirable Crystalline Silica. 

Designation E 1132–06. ASTM 

International: West Conshohocken, PA. 

OSHA–2010–0034–1504 

[ASTM] ASTM International. (2009). 

Standard Practice for Health 

Requirements Relating to Occupational 

Exposure to Respirable Crystalline Silica 

for Construction and Demolition 

Activities. Designation: E 1132–09. 

ASTM International: West 

Conshohocken, PA. OSHA–2010–0034– 

1466 

[ATS] American Thoracic Society 

Documents. (2003). American Thoracic 

Society Statement: Occupational 

Contribution to the Burden of Airway 

Disease. Am J Respir Crit Care Med. 167: 

787–797. OSHA–2010–0034–1332 

[ATS] American Thoracic Society Committee 

of the Scientific Assembly on 

Environmental and Occupational Health. 

(1997). Adverse effects of crystalline 

silica exposure. Am J Respir Crit Care 

Med 155:761–768. OSHA–2010–0034– 

0283 

[ATS/ERS] American Thoracic Society/

European Respiratory Society. (2005) 

Task Force: Standardisation of 

Spirometry. Eur Respir J; 26: 319–338, 

2005. http://www.thoracic.org/

statements/resources/pfet/PFT2.pdf 

OSHA–2010–0034–1507 

Ashford NA, Ayers C, and Stone RF. (1985). 

Using Regulation to Change the Market 

for Innovation. Harvard Environmental 

Law Review 9(2): 871–906. OSHA–2010– 

0034–0536 

Attfield MD and Costello J. (2004). 

Quantitative exposure-response for silica 

dust and lung cancer in Vermont granite 

workers. Am J Ind Med 45:129–138. 

OSHA–2010–0034–0543 

Attfield MD and Costello J. (2001). Use of an 

existing exposure database to evaluate 

lung cancer risk and silica exposure in 

Vermont granite workers. In: Hagberg M, 

Knave B, Lillenberg L, Westberg H, eds. 

National Institute for Working and Life: 

Proceedings of the 2001 Conference in 

Exposure Assessment in Epidemiology 

and Practice, June 10–13, 2001, 

Goteborg, Sweden. National Institute for 

Working and Life, 341–343. Cited in: 

Kuempel ED, Tran, C, Bailer AJ, Porter 

DW, Hubbs AF, Castranova V. (2001). 

Biological and statistical approaches to 

predicting human lung cancer risk from 

silica. JEPTO 20(Suppl. 1):15–32. 

OSHA–2010–0034–0284 

Attfield M and Weissman D. (2009). Using 

Digital Chest Images to Monitor the 

Health of Coal Miners and Other 

Workers. NIOSH Science Blog. http:// 

blogs.cdc.gov/niosh-science-blog/2009/

06/xray/ OSHA–2010–0034–1495 

Ayer HE. (1995). The origins of health 

standards for quartz exposure. Am J 

Public Health. 85(10):1453–4. OSHA– 

2010–0034–1489 

Balaan MR, Banks DE. (1992). Silicosis. In: 

Rom WN, editor. Environmental and 

Occupational Medicine, Second Edition. 

p. 345–358. OSHA–2010–0034–0289 

Balmes J. (1990). Silica exposure and 

tuberculosis: An old problem with some 

new twists. J Occup Med 32:114–115. 

Cited in: [NIOSH] National Institute for 

Occupational Safety and Health. 2003. 

Work-related lung disease surveillance 

report 2002. Cincinnati, OH: U.S. 

Department of Health and Human 

Services, Public Health Service, Centers 

for Disease Control and Prevention. 

DHHS (NIOSH) Publication No. 2003– 

111. OSHA–2010–0034–1307 

Banks DE. (2005). Silicosis. In: Rosenstock L, 

Cullen MR, Brodkin CA, and Redlich 

CA, editors. (2005). Textbook of clinical 

occupational and environmental 

medicine. 2nd ed. Philadelphia, PA. 

Elsevier Saunders. 380–392. OSHA– 

2010–0034–0291 

[BCTD] Building and Construction Trades 

Department. (2001). Proposed Silica 

Standard for Construction. Revised Draft 

8/28/01. OSHA–2010–0034–1509 

[BCTD] Building and Construction Trades 

Department (2009). BCTD Points on 

Silica Standard. OSHA–2010–0034–1508 

Becklake MR. (1994). Pneumoconioses. In: 

Murray JF, Nadel JA. (1994). Textbook of 

respiratory medicine. Second edition. 

Philadelphia, PA. W.B. Saunders Co. p. 

1955–2001. OSHA–2010–0034–0294 

Becklake MR, Irwig L, Kielowski D, Webster 

I, deBeer M, and Landau S. (1987). The 

predictors of emphysema in South 

African gold miners. Am Rev Respir Dis 

135:1234–1241. OSHA–2010–0034–0293 

Be ́gin R, Bergeron D, Samson L, Boctor M, 

and Cantin A. (1987a). CT assessment of 

silicosis in exposed workers. Am J 

Roentgenol 148:509–514. OSHA–2010– 

0034–0295 

Be ́gin R, Ostiguy G, Cantin A, and Bergeron 

D. (1988). Lung function in silicaexposed workers. A relationship to 

disease severity assessed by CT scan. 

Chest 94:539–545. OSHA–2010–0034– 

0296 

Be ́gin R, Filion R, and Ostiguy G. (1995). 

Emphysema in silica- and asbestosexposed workers seeking compensation. 

A CT scan study. Chest 108:647–655. 

OSHA–2010–0034–0971 

[BLS] Bureau of Labor Statistics. (2010). Fatal 

occupational injuries, annual average 

hours worked, total employment, and 

rates of fatal occupational injuries by 

selected worker characteristics, 

occupations, and industries, 2007. U.S. 

Department of Labor, Washington, D.C. 

http://www.bls.gov/iif/oshwc/cfoi/cfoi_

rates_2007h.pdf OSHA–2010–0034–1349 

Blum T, Kollmeier J, Ott S, Serke M, 

Scho ̈nfeld N, and Bauer T. (2008). 

Computed tomography for diagnosis and 

grading of dust-induced occupational 

lung disease. Current Opinions in 

Pulmonary Medicine 14:135–140. 

OSHA–2010–0034–1293 

Bolsaitis PP and Wallace WE. (1996). The 

structure of silica surfaces in relation to 

cytotoxicity. In: Castranova V, 

Vallyathan V, and Wallace WE, editors. 

Silica and silica-induced lung diseases. 

Boca Raton, FL: CRC Press, Inc. p. 79– 

89. OSHA–2010–0034–0298 

Borm PJ, Driscoll K. (1996). Particles, 

inflammation and respiratory tract 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56477 

carcinogenesis. Toxicol Lett. 88(1– 

3):109–13. OSHA–2010–0034–1341 

Boujemaa W, Lauwerys R, and Bernard A. 

(1994). Early indicators of renal 

dysfunction in silicotic workers. Scand J 

Work Environ Health 20:180–183. 

OSHA–2010–0034–0299 

Brown TP and Rushton L. (2005a). Mortality 

in the UK industrial silica sand industry: 

1. Assessment of exposure to respirable 

crystalline silica. Occup Environ Med 

62:442–445. OSHA–2010–0034–0303 

Brown TP and Rushton L. (2005b). Mortality 

in the UK industrial silica sand industry: 

2. A retrospective cohort study. Occup 

Environ Med 62:446–452. OSHA–2010– 

0034–0304 

Brown LM, Gridley G, Olsen JH, Mellemkjaer 

L, Linet MS, and Fraumeni JF, Jr. (1997). 

Cancer risk and mortality patterns among 

silicotic men in Sweden and Denmark. J 

Occup Environ Med 39:633–638. OSHA– 

2010–0034–0974 

Bruch J, Rehn S, Rehn B, Borm PJ, and Fubini 

B. (2004). Variation of biological 

responses to different respirable quartz 

flours determined by a vector model. Int 

J Hyg Environ Health 207:203–216. 

OSHA–2010–0034–0305 

Buchanan D, Miller BG, Soutar CA. (2003). 

Quantitative relations between exposure 

to respirable quartz and risk of silicosis. 

Occup. Environ. Med. 60:159–164. 

OSHA–2010–0034–0306 

Bureau of Mines, U.S. (1992). Crystalline 

Silica Primer. U.S. Department of the 

Interior, U.S. Bureau of Mines, Branch of 

Industrial Minerals. OSHA–2010–0034– 

1334 

Burgess, WA. (1995). Recognition of Health 

Hazards in Industry, 2nd Edition. New 

York: John Wiley and Sons, Inc. Pages 

464–473. OSHA–2010–0034–0575 

Burmeister, S. (2001). OSHA compliance 

issues: Exposure to crystalline silica 

during a foundry ladle relining process. 

R. Fairfax (column ed.), Applied 

Occupational and Environmental 

Hygiene 16(7):718–720. OSHA–2010– 

0034–0576 

Cakmak GD, Schins RP, Shi T, Fenoglio I, 

Fubini B, and Borm PJ. (2004). In vitro 

genotoxicity assessment of commercial 

quartz flours in comparison to standard 

DQ12 quartz. Int J Hyg Environ Health 

207:105–113. OSHA–2010–0034–0307 

Calvert GM, Rice FL, Boiano JM, Sheehy JW, 

and Sanderson WT. (2003). Occupational 

silica exposure and risk of various 

diseases: an analysis using death 

certificates from 27 states of the United 

States. Occup Environ Med 60:122–129. 

OSHA–2010–0034–0309 

Calvert GM, Steenland K, and Palu S. (1997). 

End-stage renal disease among silicaexposed gold miners: A new method for 

assessing incidence among 

epidemiologic cohorts. JAMA 277:1219– 

1223. OSHA–2010–0034–0976 

Carta P, Aru G, and Manca P. (2001). 

Mortality from lung cancer among 

silicotic patients in Sardinia: An update 

study with 10 more years of follow up. 

Occup Environ Med 58:786–793. OSHA– 

2010–0034–0311 

Carta P, Cocco P, and Picchiri G. (1994). Lung 

cancer mortality and airways obstruction 

among metal miners exposed to silica 

and low levels of radon daughters. Am 

J Ind Med 25:489–506. OSHA–2010– 

0034–0312 

Cassidy A, ‘t Mannetje A, van Tongeren M, 

Field JK, Zaridze D, SzeszeniaDabrowska N, Rudnai P, Lissowska J, 

Fabianova E, Mates D, Bencko V, 

Foretova L, Janout V, Fevotte J, Fletcher 

T, Brennan P, and Boffetta P. (2007). 

Occupational exposure to crystalline 

silica and risk of lung cancer: A 

multicenter case-control study in 

Europe. Epidemiology 18:36–43. OSHA– 

2010–0034–0313 

Castranova V, Dalal NS, and Vallyathan V. 

(1996). Role of surface free radicals in 

the pathogenicity of silica. In: Castranova 

V, Vallyathan V, and Wallace WE, 

editors. Silica and silica-induced lung 

diseases. Boca Raton, FL: CRC Press, Inc. 

p. 91–105. OSHA–2010–0034–0314 

Castranova V, Huffman LJ, Judy DJ, Bylander 

JE, Lapp LN, Weber SL, Blackford JA, 

and Dey RD. (1998). Enhancement of 

nitric oxide production by pulmonary 

cells following silica exposure. Environ 

Health Perspect 106:1165–1169. OSHA– 

2010–0034–1294 

Castranova V, Vallyathan V, Ramsey DM, 

McLaurin JL, Pack D, Leonard S, Barger 

MW, Ma JYC, Dalal NS, and Teass A. 

(1997). Augmentation of pulmonary 

reactions to quartz inhalation by trace 

amounts of iron-containing particles. 

Environ Health Perspect 105:1319–1324. 

OSHA–2010–0034–0978 

[CDC] Centers for Disease Control and 

Prevention. (1998). Silicosis deaths 

among young adults—United States, 

1968–1994. MMWR 47:331–335.OSHA– 

2010–0034–0318 

[CDC] Centers for Disease Control and 

Prevention. (2005). Silicosis mortality, 

prevention, and control—United States, 

1968–2002. MMWR 54:401–405. OSHA– 

2010–0034–0319 

[CDC]. Centers for Disease Control and 

Prevention. (2000). Targeted tuberculin 

testing and treatment of latent 

tuberculosis infection. MMWR 49: No 

RR–6. http://www.cdc.gov/mmwr/PDF/

rr/rr4906.pdf. OSHA–2010–0034–1510 

[CDC]. Centers for Disease Control and 

Prevention. (2009). Trends in 

Tuberculosis — United States, 2008. 

MMWR 58(10):249–253. http://

www.cdc.gov/mmwr/preview/

mmwrhtml/mm5810a2.htm OSHA– 

2010–0034–1496 

Cecala AB, Organiseak JA, Zimmer JA, 

Heitbrink WA, Moyer ES, Schmitz M, 

Ahrenholtz E, Coppock CC, and 

Andrews EH. (2005). Reducing enclosed 

cab drill operators respirable dust 

exposure with effective filtration and 

pressurization techniques. Journal of 

Occupational and Environmental 

Hygiene 2:54–63. OSHA–2010–0034– 

0590 

Checkoway H, Heyer NJ, Demers PA, Breslow 

NE. (1993). Mortality among workers in 

the diatomaceous earth industry. Br J Ind 

Med 50:586–597. OSHA–2010–0034– 

0324 

Checkoway H, Heyer NJ, Demers PA, Gibbs 

GW. (1996). Reanalysis of mortality from 

lung cancer among diatomaceous earth 

industry workers, with consideration of 

potential confounding by asbestos 

exposure. Occup Environ Med 53:645– 

647. OSHA–2010–0034–0325 

Checkoway H, Heyer NJ, Seixas NS, Welp 

EAE, Demers PA, Hughes JM, Weill H. 

(1997). Dose-response associations of 

silica with nonmalignant respiratory 

disease and lung cancer mortality in the 

diatomaceous earth industry. Am J 

Epidemiol 145:680–688. OSHA–2010– 

0034–0326 

Checkoway H and Franzblau A. (2000). Is 

silicosis required for silica-associated 

lung cancer? Am J Ind Med 37:252–259. 

OSHA–2010–0034–0323 

Checkoway H, Heyer NJ, Seixas NS, and 

Demers PA. (1998). The authors reply 

[letters to the editor]. Am J Epidemiol 

148:308–309. OSHA–2010–0034–0984 

Checkoway H, Hughes JM, Weill H, Seixas 

NS, and Demers PA. (1999). Crystalline 

silica exposure, radiological silicosis, 

and lung cancer mortality in 

diatomaceous earth industry workers. 

Thorax 54:56–59. OSHA–2010–0034– 

0327 

Chen J, McLaughlin JK, Zhang J, Stone BJ, 

Luo J, Chen R, Dosemeci M, Rexing SH, 

Wu Z, Hearl FJ, McCawley MA, Blot, WJ 

(1992). Mortality among dust-exposed 

Chinese mine and pottery workers. JOM 

34:311–316. OSHA–2010–0034–0329 

Chen W and Chen J. (2002). Nested casecontrol study of lung cancer in four 

Chinese tin mines. Occup Environ Med 

59:113–118. OSHA–2010–0034–0330 

Chen W, Hnizdo E, Chen JQ, Attfield MD, 

Gao P, Hearl F, Lu J, and Wallace WE. 

(2005). Risk of silicosis in cohorts of 

Chinese tin and tungsten miners, and 

pottery workers (I): An epidemiological 

study. Am J Ind Med 48:1–9. OSHA– 

2010–0034–0985 

Chen W, Yang J, Chen J, and Bruch J. (2006). 

Exposures to silica mixed dust and 

cohort mortality study in tin mines: 

Exposure-response analysis and risk 

assessment of lung cancer. Am J Ind Med 

49:67–76. OSHA–2010–0034–0331 

Chen W, Zhuang Z, Attfield MD, Chen BT, 

Gao P, Harrison JC, Fu C, Chen J, Wallace 

WE (2001). Exposure to silica and 

silicosis among tin miners in China: 

exposure-response analyses and risk 

assessment. Occup Environ Med 58:31– 

37. OSHA–2010–0034–0332 

Cherry NM, Burgess GL, Turner S, and 

McDonald JC. (1998). Crystalline silica 

and risk of lung cancer in the potteries. 

Occup Environ Med 55:779–785. OSHA– 

2010–0034–0335 

Churchyard GJ, Ehrlich R, teWaterNaude JM, 

Pemba L, Dekker K, Vermeijs M, White 

N, and Myers J. (2004). Silicosis 

prevalence and exposure-response 

relations in South African goldminers. 

Occup Environ Med 61:811–816. OSHA– 

2010–0034–0986 

Churchyard GJ, Pemba L, Magadla B, Dekker 

K, Vermeijs M, Ehrlich R, teWaterNaude 

J, Myers J, White N. (2003). Silicosis 

prevalence and exposure-response 

relationships in older black mineworkers 

on a South African goldmine. Final 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56478 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

Report: Safety in Mines Research 

Advisory Committee, University of Cape 

Town. May, 2003. OSHA–2010–0034– 

1295 

Cocco PL, Carta P, Flore V, Picchiri GF, and 

Zucca C. (1994). Lung cancer mortality 

among female mine workers exposed to 

silica. J Occup Med 36:894–898. OSHA– 

2010–0034–0988 

Cocco P, Ward MH, and Buiatti E. (1996). 

Occupational risk factors for gastric 

cancer: An overview. Epidemiol Rev 

18:218–234. OSHA–2010–0034–0340 

Costa D and Kahn M. (2003). The Rising 

Value of Nonmarket Goods, American 

Economic Review, (93:2), pp. 227–233. 

OSHA–2010–0034–0610 

Costa D and Kahn M. (2004). Changes in the 

Value of Life, 1940–1980, Journal of Risk 

and Uncertainty, (29:2), pp. 159–180. 

OSHA–2010–0034–0609 

Costello J and Graham WG. (1988). Vermont 

granite workers’ mortality study. Am J 

Ind Med 13:483–497. OSHA–2010– 

0034–0991 

Costello J, Castellan RM, Swecker GS, and 

Kullman GJ. (1995). Mortality of a cohort 

of U.S. workers employed in the crushed 

stone industry, 1940–1980. Am J Ind 

Med 27:625–640. OSHA–2010–0034– 

0990 

Cowie RL. (1988). The influence of silicosis 

on deteriorating lung function in gold 

miners. Chest 113:340–343. OSHA– 

2010–0034–0993 

Cowie RL and Mabena SK. (1991). Silicosis, 

chronic airflow limitation, and chronic 

bronchitis in South African gold miners. 

Am Rev Respir Dis 143:80–84. OSHA– 

2010–0034–0342 

Cowie RL, Hay M, and Thomas RG. (1993). 

Association of silicosis, lung 

dysfunction, and emphysema in gold 

miners. Thorax 48:746–749. OSHA– 

2010–0034–0341 

Cowie RL. (1994). The epidemiology of 

tuberculosis in gold miners with 

silicosis. Am J Resp Crit Care Med 

150:1460–1462. OSHA–2010–0034–0992 

Craighead JE and Vallyathan NV. (1980). 

Cryptic pulmonary lesions in workers 

occupationally exposed to dust 

containing silica. JAMA 244:1939–1941. 

OSHA–2010–0034–0995 

[CSTE] Council of State and Territorial 

Epidemiologists. (2005). Putting data to 

work: Occupational health indicators 

from thirteen pilot states for 2000. In 

collaboration with National Institute for 

Occupational Safety and Health and 

Centers for Disease Control and 

Prevention. Available from: http://

www.cste.org/pdffiles/newpdffiles/cste_

ohi.pdf OSHA–2010–0034–0996 

Davis GS. (1996). Silica. In: Harber P, 

Schenker MB, and Balmes JR, editors. 

Occupational and environmental 

respiratory disease. 1st ed. St. Louis, 

MO: Mosby-Year Book, Inc. p. 373–399. 

OSHA–2010–0034–0998 

Davis LK, Wegman DH, Monson RR, and 

Froines J. (1983). Mortality experience of 

Vermont granite workers. Am J Ind Med 

4:705–723. OSHA–2010–0034–0999 

de Beer M, Kielkowski D, Yach D, and 

Steinberg M. (1992). Selection bias in a 

case-control study of emphysema. South 

Afr J Epidemiol Infect 7:9–13. OSHA– 

2010–0034–1000 

de Klerk NH and Musk AW. (1998). Silica, 

compensated silicosis, and lung cancer 

in Western Australia goldminers. Occup 

Environ Med 55:243–248. OSHA–2010– 

0034–0345 

Ding M, Chen F, Shi X, Yucesoy B, Mossman 

B, and Vallyathan V. (2002). Diseases 

caused by silica: Mechanisms of injury 

and disease development. Int 

Immunopharmacol 2:173–182. OSHA– 

2010–0034–1002 

[DOL/NIOSH] Department of Labor/National 

Institute for Occupational Safety and 

Health. (2003). Respirator Usage in 

Private Sector Firms, 2001. September 

2003. OSHA–2010–0034–1492 

Donaldson K and Borm PJA. (1998). The 

quartz hazard: A variable entity. Ann 

Occup Hyg 42:287–294. OSHA–2010– 

0034–1004 

Dorman P and Hagstrom P. (1998). Wage 

compensation for dangerous work 

revisited, Industrial and Labor Relations 

Review, 52:1, pp. 116–135. OSHA–2010– 

0034–1265 

Driscoll KE and Guthrie GD. (1997). 

Crystalline silica and silicosis. In: Roth 

RA, editor. Comprehensive toxicology, 

volume 8: Toxicology of the respiratory 

system. Oxford, UK: Pergamon, Elsevier 

Science Ltd. p. 373–391. OSHA–2010– 

0034–0347 

[EIA] Energy Information Administration 

(2011). Annual Energy Outlook 2011 

with Projections to 2035. Washington, 

DC. U.S. Energy Information 

Administration. April 2011. DOE/EIA– 

0383(2011) http://www.eia.gov/forecasts/ 

archive/aeo11/pdf/0383(2011).pdf 

OSHA–2010–0034–1494 

Eisen EA, Wegman DH, and Louis TA. 

(1983). Effects of selection in a 

prospective study of forced expiratory 

volume in Vermont granite workers. Am 

Rev Respir Dis 128:587–591. OSHA– 

2010–0034–0349 

Eisen EA, Wegman DH, Louis TA, Smith TJ, 

and Peters JM. (1995). Healthy worker 

effect in a longitudinal study of onesecond forced expiratory volume (FEV1) 

and chronic exposure to granite dust. Int 

J Epidemiol 24:1154–1161. OSHA–2010– 

0034–1010 

Eastern Research Group (ERG, 2007a). 

Rulemaking Support for Supplemental 

Economic Feasibility Data for a 

Preliminary Economic Impact Analysis 

of a Proposed Crystalline Silica 

Standard; Updated Cost and Impact 

Analysis of the Draft Crystalline Silica 

Standard for Construction. Task Report. 

Submitted to Occupational Safety And 

Health Administration, Directorate of 

Evaluation and Analysis, Office of 

Regulatory Analysis under Task Order 

11, Contract No. DOLJ049F10022. April 

20, 2007. 

Eastern Research Group (ERG, 2007b). 

Rulemaking Support for Supplemental 

Economic Feasibility Data for a 

Preliminary Economic Impact Analysis 

of a Proposed Crystalline Silica 

Standard; Updated Cost and Impact 

Analysis of the Draft Crystalline Silica 

Standard for General Industry. Task 

Report. Submitted to Occupational 

Safety And Health Administration, 

Directorate of Evaluation and Analysis, 

Office of Regulatory Analysis under Task 

Order 11, Contract No. DOLJ049F10022. 

April 20, 2007. 

Eastern Research Group (ERG, 2007c). 

Rulemaking Support for Supplemental 

Economic Feasibility Data for a 

Preliminary Economic Impact Analysis 

of a Proposed Crystalline Silica 

Standard; Assessment of Foreign Trade 

Impacts on Affected Industries. Task 

Report. Submitted to Occupational 

Safety And Health Administration, 

Directorate of Evaluation and Analysis, 

Office of Regulatory Analysis under Task 

Order 11, Contract No. DOLJ049F10022. 

April 20, 2007. 

Eastern Research Group, Inc. (2008). 

Technological Feasibility Study of 

Regulatory Alternatives for a Proposed 

Crystalline Silica Standard for General 

Industry, Volumes 1 and 2. 

Eastern Research Group, Inc. (2008). 

Technological feasibility study of 

regulatory alternatives for a proposed 

crystalline silica standard for 

construction. 

Eastern Research Group (ERG, 2013). Revised 

Excel Spreadsheet Support for OSHA’s 

Preliminary Economic Analysis for 

Proposed Respirable Crystalline Silica 

Standard: Excel Spreadsheets of 

Economic Costs and Impacts. Submitted 

to Occupational Safety and Health 

Administration, Directorate of Standards 

and Guidance, Office of Regulatory 

Analysis under Task Order 34, Contract 

No. Contract No. GS–10F–0125P, May 

2013. 

Eastern Research Group. ERG # OH 1460. 

Industrial Commission of Ohio, Division 

of Safety and Hygiene. Case File. OSHA– 

2010–0034–1412 

Eastern Research Group, Inc. (2001). Site visit 

report—Concrete Crusher A. 27 

September. OSHA–2010–0034–0203 

Echt A. Seiber W, Jones A, and Jones E. 

(2002). Case studies—Control of silica 

exposure in construction: Scabbling 

concrete. D. Tharr, column ed. Applied 

Occupational and Environmental 

Hygiene 17(12):809–813. OSHA–2010– 

0034–0633 

Echt A, Seiber K, Jones E, Schill D, Lefkowitz 

D, Sugar J, and Hoffner K. (2003). Control 

of respirable dust and crystalline silica 

from breaking concrete with a 

jackhammer. Applied Occupational and 

Environmental Hygiene. OSHA–2010– 

0034–1267 

Environmental Control Systems (2007). Rail 

wagon treatment system at Mountsorrel 

Quarry. Retrieved 30 November 2009 

from http://www.e-cs.co.uk/news/15/rail

-wagon-treatment-system-at-mountsorrel

-quarry. OSHA–2010–0034–0635 

Ellis Drewitt & Associates. (1997). Assessing 

dust exposures in the South Australian 

extractive industry: A pilot program, 

parts A and B. CAN 057960433. Glenelg, 

South Australia. OSHA–2010–0034– 

0647 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56479 

Finkelstein MM. (1998). Radiographic 

silicosis and lung cancer risk among 

workers in Ontario. Am J Ind Med 

34:244–251. OSHA–2010–0034–1014 

Finkelstein MM. (2000). Silica, silicosis, and 

lung cancer: A risk assessment. Am J Ind 

Med 38:8–18. OSHA–2010–0034–1015 

Finkelstein MM and Verma DK. (2005). 

Mortality among Ontario members of the 

International Union of Bricklayers and 

Allied Craftworkers. Am J Ind Med 47:4– 

9. OSHA–2010–0034–0352 

Flanagan ME, Loewenherz C, and Kuhn G. 

(2001). Indoor wet concrete cutting and 

coring exposure evaluation. Applied 

Occupational and Environmental 

Hygiene 16(12):1097–1100. OSHA– 

2010–0034–0675 

Food and Drug Administration (FDA, 2003). 

Food Labeling: Trans Fatty Acids in 

Nutrition Labeling, Nutrient Content 

Claims, and health Claims. Final Rule, 

July 11, 2003. Federal Register, Volume 

68, Number 133, pp. 41434–506. OSHA– 

2010–0034–1521 

Foundry Equipment Manufacturer J. (2000). 

Personal Communication between 

Foundry Equipment Manufacturer J and 

Eastern Research Group, Inc. October 2. 

OSHA–2010–0034–0691 

Foundry Engineering Group Project—Case 

History H. (2000). Ventilation Controls 

Report and Interactive CD–ROM. 

Foundry Engineering Group Project, 

LLC; El Dorado Hills, California. OSHA– 

2010–0034–1250 

Foundry Products Supplier B. (2000a). 

Personal communication. Phone call 

between representative Number 1 of 

Foundry Products Supplier B and 

Whitney Long, Eastern Research Group, 

Inc. (November 16). OSHA–2010–0034– 

0684 

Froines J, Wegman D, and Eisen E. (1989). 

Hazard surveillance in occupational 

disease. Am J Public Health 79:26–31. 

OSHA–2010–0034–0385 

Franzblau A, Kazerooni EA, Sen A, Goodsitt 

MM, Lee SY, Rosenman KD, Lockey JE, 

Meyer CA, Gillespie BW, Petsonk EL, 

Wang ML. (2009). Comparison of Digital 

Radiographs with Film Radiographs for 

the Classification of Pneumoconiosis. 

Acad Radiol 16:669–677. OSHA–2010– 

0034–1512 

Fubini B. (1998). Surface chemistry and 

quartz hazard. Ann Occup Hyg 42:521– 

30. OSHA–2010–0034–1016 

Fubini B, Fenoglio I, Ceschino R, Ghiazza M, 

Gianmario M, Tomatis M, Borm P, 

Schins R, and Bruch J. (2004). 

Relationship between the state of the 

surface of four commercial quartz flours 

and their biological activity in vitro and 

in vivo. Int J Hyg Environ Health 207:89– 

104. OSHA–2010–0034–0353 

Gamble JF, Hessel PA, and Nicolich M. 

(2004). Relationship between silicosis 

and lung function. Scand J Work Environ 

Health 30:5–20. OSHA–2010–0034–1020 

Goldman RH and Peters JM. (1981). The 

occupational and environmental health 

history. JAMA 246:2831–2836. OSHA– 

2010–0034–1027 

Goldsmith DF. (1997). Evidence for silica’s 

neoplastic risk among workers and 

derivation of cancer risk assessment. J 

Expo Anal Environ Epidemiol. 7(3):291– 

301. OSHA–2010–0034–1333 

Goodman GB, Kaplan PD, Stachura I, 

Castronova V, Pailes WH, and Lapp NL. 

(1992). Acute silicosis responding to 

corticosteroid therapy. Chest 101:366– 

370. OSHA–2010–0034–1029 

Goodwin SS, Stanbury M, Wang ML, 

Silbergeld E, and Parker JE. (2003). 

Previously undetected silicosis in New 

Jersey decedents. Am J Ind Med 44:304– 

311. OSHA–2010–0034–1030 

Gomme P, and P Rupert (2004). Per Capita 

Income Growth and Disparity in the 

United States, 1929–2003, Federal 

Reserve Bank of Cleveland, August 15. 

OSHA–2010–0034–0710 

Graham WGB, Costello J, and Vacek PM. 

(2004). Vermont granite mortality study: 

An update with an emphasis on lung 

cancer. J Occup Environ Med 46:459– 

466. OSHA–2010–0034–1031 

Graham WG, O’Grady RV, and Dubuc B. 

(1981). Pulmonary function loss in 

Vermont granite workers. A long-term 

follow-up and critical reappraisal. Am 

Rev Respir Dis 123:25–28. OSHA–2010– 

0034–1280 

Graham WG, Weaver S, Ashikaga T, and 

O’Grady RV. (1994). Longitudinal 

pulmonary function losses in Vermont 

granite workers. A reevaluation. Chest 

106:125–130. OSHA–2010–0034–0354 

Green FHY and Vallyathan V. (1996). 

Pathologic responses to inhaled silica. 

In: Castranova V, Vallyathan V, and 

Wallace WE, editors. Silica and silicainduced lung diseases. Boca Raton, FL: 

CRC Press. p. 39–59. OSHA–2010–0034– 

1297 

Gregorini G, Feriola A, Donato F, Tira P, 

Morassi L, Tardanico R, Lancini L, and 

Maiorca R. (1993). Association between 

silica exposure and necrotizing 

crescentic glomerulonephritis with 

p-ANCA and anti-MPO antibodies: A 

hospital-based case-control study. Adv 

Exp Med Biol 336:435–440. OSHA– 

2010–0034–1032 

Grenier, M.G. (1987). Evaluation of a Wet 

Dust Collector at an Underground 

Crushing Operation. Fifty-sixth Annual 

Technical Session. Mines Accident 

Prevention Association of Ontario, 

Canada Linch KD and Cocalis JC. (1994). 

Emerging issue: silicosis prevention in 

construction. Applied Occupational and 

Environmental Hygiene 9(8): 539–542. 

OSHA–2010–0034–0717 

Greskevitch M and Symlal G. (2009). State/ 

NIOSH Silicosis Surveillance Meeting: 

Sand use for Abrasive Blasting State 

DOTs with Bans and Annual U.S. 

Consumption. OSHA–2010–0034–1420 

Gue ́nel P, Breum NO, Lynge E. (1989a). 

Exposure to silica dust in the Danish 

stone industry. Scand J Work Environ 

Health 15(2):147–153. OSHA–2010– 

0034–1034 

Gue ́nel P, H<jberg G, Lynge E. (1989b). 

Cancer incidence among Danish stone 

workers. Scand J Work Environ Health 

15(4): 265–270. OSHA–2010–0034–0356 

Gustafsson A, Eriksson H, Noren O. Dust 

concentrations during operations with 

farm, forest and entrepreneur machines. 

Special meddelande 1978;S:26. As cited 

in Swanepoel et al. (2010). OSHA–2010– 

0034–1491 

Guthrie GD, Jr. and Heaney PJ. (1995). 

Mineralogical characteristics of silica 

polymorphs in relation to their biological 

activities. Scand J Work Environ Health 

21:5–8. OSHA–2010–0034–1035 

Guyatt GH, Berman LB, Pugsley SO, 

Chambers LW. (1987). A measure of 

quality of life for clinical trials in 

chronic lung disease. Thorax. 42; 773– 

778. OSHA–2010–0034–1342 

Hall RE and Jones CI. (2007). The Value of 

Life and the Rise in Health Spending, 

Quarterly Journal of Economics, CXXII, 

pp. 39–72. OSHA–2010–0034–0720 

Hall RM, Heitbrink WA, and Reed LD. (2002). 

Evaluation of a tractor cab using realtime aerosol counting instrumentation. 

Applied Occupational and 

Environmental Hygiene 17(1): 47–54. 

January. OSHA–2010–0034–0719 

Hallin N. (1983). Occurrence of quartz in the 

construction sector. Bygghalsan, the 

Construction Industry’s Organization for 

Working Environment, Safety, and 

Health. Report 1983–04–01. OSHA– 

2010–0034–1418 

Harrison J, Chen Harsco Track Technologies 

(2003). Personal communication between 

a Harsco Track Technologies 

representative and Eastern Research 

Group, Inc. 17 June. OSHA–2010–0034– 

0732 

Harrison J, Chen JQ, Miller W, Chen W, 

Hnizdo E, Lu J, Chisolm W, Keane M, 

Gao P, and Wallace W. (2005). Risk of 

silicosis in cohorts of Chinese tin and 

tungsten miners and pottery workers (II): 

Workplace-specific silica particle surface 

composition. Am J Ind Med 48:10–15. 

OSHA–2010–0034–1036 

Haustein UF and Anderegg U. (1998). Silicainduced scleroderma—clinical and 

experimental aspects. J Rheumatol 

25:1917–1926. OSHA–2010–0034–1040 

Hertzberg VS, Rosenman KD, Reilly MJ, and 

Rice CH. (2002). Effect of occupational 

silica exposure on pulmonary function. 

Chest 122:721–728. OSHA–2010–0034– 

0358 

Hessel PA. (2006) The prevalence of silicosis 

in the brick industry: A study conducted 

for the Brick Industry Association. 

Palatine, Il.: EpiLung Consulting, Inc. 

May 30, 2006. OSHA–2010–0034–1299 

Hessel PA, Sluis-Cremer GK, Hnizdo E. 

(1986). Case-control study of silicosis, 

silica exposure, and lung cancer in white 

South African gold miners. Am J Ind 

Med 10:57–62. OSHA–2010–0034–0359 

Hessel PA, Sluis-Cremer GK, Hnizdo E. 

(1990). Silica Exposure, Silicosis, and 

Lung Cancer: a Necropsy Study. Br J Ind 

Med 47(1):4–9. OSHA–2010–0034–1043 

Hessel PA, Sluis-Cremer GK, Hnizdo E, Faure 

MH, Thomas RG, and Wiles FJ. (1988). 

Progression of silicosis in relation to 

silica dust exposure. Ann Occup Hyg 

32:689–696. OSHA–2010–0034–1042 

Hintermann B, Alberini A, and Markandya A. 

(2010). Estimating the value of safety 

with labour market data: are the results 

trustworthy? Applied Economics, 42(9), 

pp. 1085–1100. OSHA–2010–0034–0739 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56480 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

Hnizdo E. (1992). Loss of lung function 

associated with exposure to silica dust 

and with smoking and its relation to 

disability and mortality in South African 

gold miners. Br J Ind Med 49:472–479. 

OSHA–2010–0034–1046 

Hnizdo E. (1990). Combined effect of silica 

dust and tobacco smoking on mortality 

from chronic obstructive lung disease in 

gold miners. Br J Ind Med 47:656–664. 

OSHA–2010–0034–1045 

Hnizdo E, Baskind E, and Sluis-Cremer GK. 

(1990). Combined effect of silica dust 

exposure and tobacco smoking on the 

prevalence of respiratory impairments 

among gold miners. Scand J Work 

Environ Health 16:411–422. OSHA– 

2010–0034–1047 

Hnizdo E, Murray J, and Klempman S. 

(1997). Lung cancer in relation to 

exposure to silica dust, silicosis, and 

uranium production in South African 

gold miners. Thorax 52:271–275. OSHA– 

2010–0034–1049 

Hnizdo E, Murray J, Sluis-Cremer GK, and 

Thomas RG. (1993). Correlation between 

radiological and pathological diagnosis 

of silicosis: An autopsy population based 

study. Am J Ind Med 24:427–445. 

OSHA–2010–0034–1050 

Hnizdo E and Murray J. (1998). Risk of 

pulmonary tuberculosis relative to 

silicosis and exposure to silica dust in 

South African gold miners. Occup 

Environ Med 55:496–502. OSHA–2010– 

0034–0360 

Hnizdo E, Murray J, and Davison A. (2000). 

Correlation between autopsy findings for 

chronic obstructive airways disease and 

in-life disability in South African gold 

miners. Int Arch Occup Environ Health 

73:235–244. OSHA–2010–0034–1048 

Hnizdo E and Sluis-Cremer GK. (1991). Silica 

exposure, silicosis, and lung cancer: A 

mortality study of South African gold 

miners. Br J Ind Med 48:53–60. OSHA– 

2010–0034–1051 

Hnizdo E and Sluis-Cremer G. (1993). Risk of 

silicosis in a cohort of white South 

African gold miners. Am J Ind Med 

24:447–457. OSHA–2010–0034–1052 

Hnizdo E, Sluis-Cremer GK, and Abramowitz 

JA. (1991). Emphysema type in relation 

to silica dust exposure in South African 

gold miners. Am Rev Respir Dis 

143:1241–1247. OSHA–2010–0034–1053 

Hnizdo E, Sluis-Cremer GK, Baskind E, and 

Murray J. (1994). Emphysema and airway 

obstruction in non-smoking South 

African gold miners with long exposure 

to silica dust. Occup Environ Med 

51:557–563. OSHA–2010–0034–1054 

Hnizdo E and Vallyathan V. (2003). Chronic 

obstructive pulmonary disease due to 

occupational exposure to silica dust: A 

review of epidemiological and 

pathological evidence. Occup Environ 

Med 60:237–243. OSHA–2010–0034– 

1055 

Hoffer K. (2007). How to make your very own 

jackhammer spray dust control. New 

Jersey Laborers Health and Safety Fund. 

Available at: http://www.njlaborers.org/

health/pdfs/other/jackhammer.pdf 

OSHA–2010–0034–0741 

Holman CDJ, Psaila-Savona P, Roberts M, and 

McNulty JC. (1987). Determinants of 

chronic bronchitis and lung dysfunction 

in Western Australian gold miners. Br J 

Ind Med 44:810–818. OSHA–2010– 

0034–1056 

Horner MJ, Ries LAG, Krapcho M, Neyman 

N, Aminou R, Howlader N, Altekruse SF, 

Feuer EJ, Huang L, Mariotto A, Miller 

BA, Lewis DR, Eisner MP, Stinchcomb 

DG, Edwards BK (eds). (2009). SEER 

Cancer Statistics Review, 1975–2006, 

National Cancer Institute. Bethesda, MD, 

http://seer.cancer.gov/csr/1975_2006/, 

based on November 2008 SEER data 

submission, posted to the SEER Web site, 

2009. OSHA–2010–0034–1343 

Hotz P, Gonzalez-Lorenzo J, Siles E, 

Trujillano G, Lauwerys R, and Bernard 

A. (1995). Subclinical signs of kidney 

dysfunction following short exposure to 

silica in the absence of silicosis. 

Nephron 70:438–442. OSHA–2010– 

0034–0361 

Hubbs et al. (2005). Abrasive Blasting Agents: 

Designing studies to evaluate risk. 

Journal of Toxicology and Environmental 

Health, Part A, 68:999–1016. OSHA– 

2010–0034–1345 

Hughes JM, Weill H, Checkoway H, Jones RN, 

Henry MM, Heyer NJ, Siexas NS, and 

Demers PA. (1998). Radiographic 

evidence of silicosis risk in the 

diatomaceous earth industry. Am J 

Respir Crit Care Med 158:807–814. 

OSHA–2010–0034–1059 

Hughes JM, Weill H, Rando RJ, Shi R, 

McDonald AD, and McDonald JC. (2001). 

Cohort mortality study of North 

American industrial sand workers. II. 

Case-referent analysis of lung cancer and 

silicosis deaths. Ann Occup Hyg 45:201– 

207. OSHA–2010–0034–1060 

Hughes JM, Jones RN, Gilson JC, Hammad 

YY, Samimi B, Hendrick DJ, TurnerWarwick M, Doll NJ, and Weill H. 

(1982). Determinants of progression in 

sandblasters’ silicosis. Ann Occup Hyg 

26:701–712. OSHA–2010–0034–0362 

Humerfelt S, Eide GE, and Gulsvik A. (1998). 

Association of years of occupational 

quartz exposure with spirometric airflow 

limitation in Norwegian men aged 30–46 

years. Thorax 53:649–655. OSHA–2010– 

0034–1061 

Inforum, Inc. (Jeffrey F. Werling, Inforum) 

Preliminary Economic Analysis for 

OSHA’s Proposed Crystalline Silica 

Rule: Industry and Macroeconomic 

Impacts. Revised Draft Final Report for 

the Occupational Safety and Health 

Administration (including 

accompanying spreadsheet workbook). 

11/30/2011. 

[IARC] International Agency for Research on 

Cancer. (1997). Monographs on the 

evaluation of carcinogenic risks to 

humans: Silica, some silicates, coal dust 

and para-aramid fibrils. Geneva, 

Switzerland: World Health Organization. 

68:41–242. OSHA–2010–0034–1062 

[IARC] International Agency for Research on 

Cancer. (2009). Special Report: Policy. A 

review of human carcinogens—Part C: 

metals, arsenic, dusts, and fibres. Lancet 

10:453–454. OSHA–2010–0034–1474 

[IARC] International Agency for Research on 

Cancer. (2012). Monographs on the 

evaluation of carcinogenic risks to 

humans. A review of human 

carcinogens: Arsenic, metals, fibres, and 

dusts. Geneva, Switzerland: World 

Health Organization. 100C:355–405. 

OSHA–2010–0034–1473 

[ILO] International Labor Organization. 

(1980). Guidelines for the use of the ILO 

international classification of 

radiographs of pneumoconioses. 

Occupational Safety and Health Series 

No. 22 (revised). Geneva, Switzerland. 

OSHA–2010–0034–1063 

[ILO] International Labor Organization. 

(2002). Guidelines for the use of the ILO 

international classification of 

radiographs of pneumoconioses. Revised 

edition 2000. Geneva, Switzerland. 

OSHA–2010–0034–1064 

[ILO] International Labor Organization. 

(2011). Guidelines for the use of the ILO 

international classification of 

radiographs of pneumoconioses. Revised 

edition 2011. Geneva, Switzerland. 

OSHA–2010–0034–1475 

[IMA/MSHA]. Industrial Minerals 

Association/Mine Safety and Health 

Administration (2008). A practical Guide 

to an Occupational Health Program for 

Respirable Crystalline Silica. Instructor 

Guide Series IG 103. January 25, 2008. 

OSHA–2010–0034–1511 

Infante-Rivard C, Armstrong B, Ernst P, 

Petitclerc M, Cloutier LG, and The ́riault 

G. (1991). Descriptive study of 

prognostic factors influencing survival of 

compensated silicotic patients. Am Rev 

Respir Dis 144:1070–1074. OSHA–2010– 

0034–1065 

Irwig LM and Rocks P. (1978). Lung function 

and respiratory symptoms in silicotic 

and nonsilicotic gold miners. Am Rev 

Respir Dis 117:429–435. OSHA–2010– 

0034–1067 

Jorna THJM, Borm PJA, Koiter KD, Slangen 

JJ, Henderson PT, and Wouters EFM. 

(1994). Respiratory effects and serum 

type III procollagen in potato sorters 

exposed to diatomaceous earth. Int Arch 

Occup Environ Health 66:217–222. 

OSHA–2010–0034–1071 

King EJ, Mohanty GP, Harrison CV, and 

Nagelschmidt G. (1953). The action of 

different forms of pure silica on the 

lungs of rats. Br J Ind Med 10:9–17. 

OSHA–2010–0034–1072 

Klockars M, Koskela RS, Jarvinen E, Kolari 

PJ, and Rossi A. (1987). Silica exposure 

and rheumatoid arthritis: A follow up 

study of granite workers 1940–81. Br 

Med J (Clin Res Ed) 294:997–1000. 

OSHA–2010–0034–1075 

Kleinschmidt I and Churchyard G. (1997). 

Variation in incidences of tuberculosis in 

subgroups of South African gold miners. 

Occup Environ Med 54:636–641. OSHA– 

2010–0034–1074 

Kniesner TJ, Viscusi WK, and Ziliak JP. 

(2010). Policy relevant heterogeneity in 

the value of statistical life: New evidence 

from panel data quantile regression. 

Journal of Risk and Uncertainty, 40, pp. 

15–31. OSHA–2010–0034–0767 

Kolev K, Doitschinov D, and Todorov D. 

(1970). Morphologic alterations in the 

kidneys by silicosis. La Medicina del 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56481 

Lavoro 61:205–210. OSHA–2010–0034– 

1077 

Koskela RS, Klockars M, Ja ̈rvinen E, Kolari 

PJ, and Rossi A. (1987). Mortality and 

disability among granite workers. Scand 

J Environ Health 13:18–25. OSHA–2010– 

0034–0363 

Koskela RS, Klockars M, Laurent H, and 

Holopainen M. (1994). Silica dust 

exposure and lung cancer. Scand J Work 

Environ Health 20:407–416. OSHA– 

2010–0034–1078 

Kramer MR, Blanc PD, Fireman E, Amital A, 

Guber A, Rhahman NA, Shitrit D. (2012). 

Artificial stone silicosis [corrected]: 

disease resurgence among artificial stone 

workers. Chest. 142(2):419–24. Erratum 

in: Chest. (2012) 142(4):1080. OSHA– 

2010–0034–1477 and OSHA–2010– 

0034–1476 

Kreiss K, Greenberg LM, Kogut SJH, Lezotte 

DC, Irvin CG, and Cherniack RM. (1989). 

Hard-rock mining exposures affect 

smokers and nonsmokers differently. 

Results of a community prevalence 

study. Am Rev Respir Dis 139:1487– 

1493. OSHA–2010–0034–1079 

Kreiss K and Zhen B. (1996). Risk of silicosis 

in a Colorado mining community. Am J 

Ind Med 30:529–539. OSHA–2010– 

0034–1080 

Kuempel ED, Tran CL, Bailer AJ, Porter DW, 

Hubbs AF, and Castranova V. (2001). 

Biological and statistical approaches to 

predicting human lung cancer risk from 

silica. J Environ Pathol Toxicol Oncol 

20:15–32. OSHA–2010–0034–1082 

Kurihara N and Wada O. (2004). Silicosis and 

smoking strongly increase lung cancer 

risk in silica-exposed workers. Ind 

Health 42:303–314. OSHA–2010–0034– 

1084 

Lacasse Y, Martin S, Simard S, and 

Desmeules M. (2005). Meta-analysis of 

silicosis and lung cancer. Scand J Work 

Environ Health 31:450–458. OSHA– 

2010–0034–0365 

Lawson R, Schenker M, McCurdy S et al. 

(1995) Exposure to amorphous silica 

fibers and other particulate matter during 

rice farming operations. Appl Occup 

Environ Hyg; 10: 677–84. As cited in 

Swanepoel et al. (2010). OSHA–2010– 

0034–1491 

Lee HS, Phoon WH, and Ng TP. (2001). 

Radiological progression and its 

predictive risk factors in silicosis. Occup 

Environ Med 58:467–471. OSHA–2010– 

0034–1086 

Lee K, Lawson RJ, Olenchock SA et al. (2004) 

Personal exposures to inorganic and 

organic dust in manual harvest of 

California citrus and table grapes. J 

Occup Environ Hyg; 1:505–14. As cited 

in Swanepoel et al. (2010). OSHA–2010– 

0034–1491 

Leidel NA, Busch KA, Crouse WE. (1975). 

Exposure Measurement Action Level and 

Occupational Environmental Variability. 

National Institute for Occupational 

Safety and Health (NIOSH). December 

1975. OSHA–2010–0034–1501 

Lind RC. (1982b). A Primer on the Major 

Issues Relating to the Discount Rate for 

Evaluating National Energy Options, in 

Discounting for Time and Risk in Energy 

Policy, R.C. Lind (ed.). Washington, DC: 

Resources for the Future. OSHA–2010– 

0034–1416 

Lofgren DJ. (1993). Silica exposure for 

concrete workers and masons. Applied 

Occupational Environmental Hygiene 

8(10):832–835. OSHA–2010–0034–1424 

Lopes AJ, Mogami R, Capone D, Tessarollo B, 

De Melo PL, and Jansen JM. (2008). Highresolution computed tomography in 

silicosis: correlation with chest 

radiography and pulmonary function 

tests. J Bras Pneumol 34:264–272. 

OSHA–2010–0034–1088 

Love RG, Waclawski ER, Maclaren WM, 

Wetherill GZ, Groat SK, Porteous RH, 

Soutar CA. (1999). Risks of respiratory 

disease in the heavy clay industry. 

Occup Environ Med 56:124–133. OSHA– 

2010–0034–0369 

Madsen FA, Rose MC, Cee R (1995). Review 

of Quartz Analytical Methodologies: 

Present and Future Needs. Appl Occup 

Environ Hyg 10(12):991–1002. OSHA– 

2010–0034–1355 

Magat W, Viscusi W, and Huber J. (1996). A 

Reference Lottery Metric for Valuing 

Health, Management Science, (42:8), pp. 

1118–1130. OSHA–2010–0034–0791 

Malmberg P, Hedenstro ̈m H, and Sundblad 

BM. (1993). Changes in lung function of 

granite crushers exposed to moderately 

high silica concentrations: A 12 year 

follow up. Br J Ind Med 50:726–731. 

OSHA–2010–0034–0370 

Manfreda J, Sidwall G, Maini K, West P, and 

Cherniack RM. (1982). Respiratory 

abnormalities in employees of the hard 

rock mining industry. Am Rev Resp Dis 

126:629–634. OSHA–2010–0034–1094 

Mannetje A, Steenland K, Attfield M, Boffetta 

P, Checkoway H, DeKlerk N, and Koskela 

RS. (2002b). Exposure-response analysis 

and risk assessment for silica and 

silicosis mortality in a pooled analysis of 

six cohorts. Occup Environ Med 59:723– 

728. OSHA–2010–0034–1089 

Mannetje A, Steenland K, Checkoway H, 

Koskela RS, Koponen M, Attfield M, 

Chen J, Hnizdo E, DeKlerk N, and 

Dosemeci M. (2002a). Development of 

quantitative exposure data for a pooled 

exposure-response analysis of 10 silica 

cohorts. Am J Ind Med 42:73–86. OSHA– 

2010–0034–1090 

McDonald JC, Cherry N, McNamee R, Burgess 

G, and Turner S. (1995). Preliminary 

analysis of proportional mortality in a 

cohort of British pottery workers 

exposed to crystalline silica. Scand J 

Work Environ Health 21:63–65. OSHA– 

2010–0034–0371 

McDonald AD, McDonald JC, Rando RJ, 

Hughes JM, and Weill H. (2001). Cohort 

mortality study of North American 

industrial sand workers. I. Mortality 

from lung cancer, silicosis and other 

causes. Ann Occup Hyg 45:193–199. 

OSHA–2010–0034–1091 

McDonald JC, McDonald AD, Hughes JM, 

Rando RJ, and Weill H. (2005). Mortality 

from lung and kidney disease in a cohort 

of North American industrial sand 

workers: An update. Ann Occup Hyg 

49:367–373. OSHA–2010–0034–1092 

McLaughlin JK, Chen JQ, Dosemeci M, Chen 

RA, Rexing SH, Wu Z, Hearl FJ, 

McCawley MA, and Blot WJ. (1992). A 

nested case-control study of lung cancer 

among silica exposed workers in China. 

Br J Ind Med 49:167–171. OSHA–2010– 

0034–0372 

Meeker JD, Cooper MR, Lefkowitz DL, and 

Susi P. (2009). Engineering control 

technologies to reduce occupational 

silica exposures in masonry cutting and 

tuckpointing. Public Health Reports, 124 

(Supplement 1):101–111. OSHA–2010– 

0034–0803 

Meijer E, Kromhout H, and Heederik D. 

(2001). Respiratory effects of exposure to 

low levels of concrete dust containing 

crystalline silica. Am J Ind Med 40:133– 

140. OSHA–2010–0034–1243 

Merchant JA and Schwartz DA. (1998). Chest 

radiology for assessment of the 

pneumoconiosis. In: Rom WN, editor. 

Environmental and occupational 

medicine. 3rd ed. Philadelphia: 

Lippincott-Raven. p. 297. OSHA–2010– 

0034–1096 

Miller BG, Hagen S, Love RG, Cowie HA, 

Kidd MW, Lorenzo S, Tielemans ELJP, 

Robertson A, Soutar CA. A follow-up 

study of miners exposed to unusual 

concentrations of quartz. Edinburgh: 

Institute of Occupational Medicine. 

(1995). (IOM Report TM/95/03). http://

www.iom-world.org/pubs/IOM_

TM9503.pdf OSHA–2010–0034–1097 

Miller BG and Buchanan D. (1997). The 

effects of exposure to diesel fumes, lowlevel radiation, and respirable dust and 

quartz, on cancer mortality in 

coalminers. Edinburgh: Institute of 

Occupational Medicine, 1997. (IOM 

Report TM/97/04). http://www.iomworld.org/pubs/IOM_TM9704.pdf 

OSHA–2010–0034–1304 

Miller BG, Hagen S, Love RG, Soutar CA, 

Cowie HA, Kidd MW, and Robertson A. 

(1998). Risks of silicosis in coalworkers 

exposed to unusual concentrations of 

respirable quartz. Occup Environ Med 

55:52–58. OSHA–2010–0034–0374 

Miller BG and Soutar CA. (2007). Observed 

and predicted silicosis risks in heavy 

clay workers. Occ Med 57:569–574. 

OSHA–2010–0034–1098 

Miller BG, MacCalman and Hutchison PA. 

(2007). Mortality over an extended 

follow-up period in coal workers 

exposed to respirable dust and quartz. 

(Institute of Occupational Medicine 

(IOM)). Research Report TM/07/06 (rev), 

November 2007 (revised October 2009). 

Edinburgh, Scotland. OSHA–2010– 

0034–1305 

Miller BG and MacCalman L (2009). Causespecific mortality in British coal workers 

and exposure to respirable dust and 

quartz. Occup Environ Med. Published 

online, doi: 10.1136/oem.2009.046151, 

October 9, 2009. OSHA–2010–0034– 

1306 

[MSHA] Mine Safety and Health 

Administration (1997). Respirable dust 

sampling survey of the Arundel 

Corporation, Havre De Grace Quarry, 

Florida Rock Industries Inc., Mine ID 18– 

00657, Havre De Grace, Maryland. 

Memorandum from Robert A. Haney, 

Chief, Environmental Asessment and 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56482 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

Contaminant Control Branch to James R 

Petrie, District Manager, M/NMS&H, 

Northeastern. OSHA–2010–0034–1419. 

Minnich. (2009b). YouTube video: Minnich 

Manufacturing remote operated dowel 

drill unit. Retrieved August 13, 2009, 

from http://www.youtube.com/user/

Buckeyeque#play/uploads/1/

35lEtJk1EOM. OSHA–2010–0034–0814 

Montes II, Ferna ́ndez GR, Reguero J, Mir 

MAC, Garcı ́a-Orda ́s E, Martı ́nez JLA, and 

Gonza ́lez CM. (2004a). Respiratory 

disease in a cohort of 2,579 coal miners 

followed up over a 20-year period. Chest 

126:622–629. OSHA–2010–0034–0376 

Montes II, Rego G, Camblor C, Quero A, 

Gonza ́lez A, and Rodrı ́guez C. (2004b). 

Respiratory disease in aggregate quarry 

workers related to risk factors and Pi 

phenotype. J Occup Environ Med 

46:1150–1157. OSHA–2010–0034–0377 

Moore E, Martin J, Muir DCF, and Edwards 

AS. (1988). Pulmonary function in 

silicosis. Ann Occ Hyg 32:705–711. 

OSHA–2010–0034–1099 

Moshammer H and Neuberger M. (2004). 

Lung cancer and dust exposure: Results 

of a prospective cohort study following 

3260 workers for 50 years. Occup 

Environ Med 61:157–162. OSHA–2010– 

0034–1282 

Mossman B, Churg A. (1998). Mechanisms in 

the pathogenesis of asbestosis and 

silicosis. Am J Respir Crit Care Med 

157:1666–1680. OSHA–2010–0034–1344 

Muhle H, Kittel B, Ernst H, Mohr U, and 

Mermelstein R. (1995). Neoplastic lung 

lesions in rat after chronic exposure to 

crystalline silica. Scand J Work Environ 

Health 21:27–29. OSHA–2010–0034– 

0378 

Muir DCF, Julian JA, Shannon HS, Verma 

DK, Sebestyen A, and Bernholz CD. 

(1989b). Silica exposure and silicosis 

among Ontario hardrock miners: III. 

Analysis and risk estimates. Am J Ind 

Med 16:29–43. OSHA–2010–0034–1101 

Muir DCF, Shannon HS, Julian JA, Verma 

DK, Sebestyen A, and Bernholz CD. 

(1989a). Silica exposure and silicosis 

among Ontario hardrock miners: I. 

Methodology. Am J Ind Med 16:5–11. 

OSHA–2010–0034–1102 

Murray J, Kielkowski D, and Reid P. (1996). 

Occupational disease trends in black 

South African gold miners. Am J Respir 

Crit Care Med 153:706–710. OSHA– 

2010–0034–1103 

Neukirk F, Cooreman J, Korobaeff M, and 

Pariente R. (1994). Silica exposure and 

chronic airflow limitation in pottery 

workers. Arch Environ Health 49:459– 

464. OSHA–2010–0034–0381 

Ng TP and Chan SL. (1991). Factors 

associated with massive fibrosis in 

silicosis. Thorax 46:229–232. OSHA– 

2010–0034–1106 

Ng TP, Chan SL, and Lee J. (1992a). 

Predictors of mortality in silicosis. 

Respir Med 86:115–119. OSHA–2010– 

0034–0383 

Ng TP, Chan SL, and Lam KP. (1987a). 

Radiological progression and lung 

function in silicosis: A ten year follow 

up study. Br Med J (Clin Res Ed) 

295:164–168. OSHA–2010–0034–1108 

Ng TP, Tsin TW, O’Kelly FJ, and Chan SL. 

(1987b). A survey of the respiratory 

health of silica-exposed gemstone 

workers in Hong Kong. Am Rev Respir 

Dis 135:1249–1254. OSHA–2010–0034– 

1113 

Ng TP and Chan SL. (1992). Lung function 

in relation to silicosis and silica 

exposure in granite workers. Eur Respir 

J 986–991.OSHA–2010–0034–1107 

Ng TP and Chan SL. (1994). Quantitative 

relations between silica exposure and 

development of radiological small 

opacities in granite workers. Ann Occup 

Hyg 38(suppl):857–863. OSHA–2010– 

0034–0382 

Ng TP, Ng YL, Lee HS, Chia KS, and Ong HY. 

(1992c). A study of silica nephrotoxicity 

in exposed silicotic and non-silicotic 

workers. Br J Ind Med 49:35–37. OSHA– 

2010–0034–0386 

Ng TP, Phoon WH, Lee HS, Ng YL, and Tan 

KT. (1992b). An epidemiological survey 

of respiratory morbidity among granite 

quarry workers in Singapore: Chronic 

bronchitis and lung function 

impairment. Ann Acad Med Singapore 

21:312–317. OSHA–2010–0034–0387 

[NIOSH, 2001] National Institute for 

Occupational Safety and Health. 

Presentation at 2001 American Industrial 

Hygiene Conference comparing health 

hazard of substitute abrasives to silica 

sand. (June 5, 2001). New Orleans, LA. 

Paper Number 114 Page 24 of AIHCE 

Abstract publication. OSHA–2010–0034– 

1422 

[NIOSH, 2000] National Institute for 

Occupational Safety and Health. Control 

of drywall sanding dust exposures. 

Applied Occupational and 

Environmental Hygiene 15:820–821. 

OSHA–2010–0034–0933 

[NIOSH, 2009] National Institute for 

Occupational Safety and Health. 

Update—Prevention of silicosis deaths. 

February 2009. DHHS (NIOSH) 

Publication No. 93–124. http://

www.cdc.gov/niosh/updates/93-124.html 

OSHA–2010–0034–1346 

[NIOSH, 2007] National Institute for 

Occupational Safety and Health. 

Silicosis: Learn the Facts! DHHS 

(NIOSH) Publication No. 2004–108. 

http://www.cdc.gov/niosh/docs/2004- 

108/ OSHA–2010–0034–1347 

[NIOSH, 2007] National Institute for 

Occupational Safety and Health. 

Recirculation filter is key to improving 

dust control in enclosed cabs. NIOSH 

2008–100. Technology News 528:1–2. 

OSHA–2010–0034–0844 

[NIOSH, 1993b] National Institute for 

Occupational Safety and Health. Indepth survey report: Control technology 

for removing lead-based paint from steel 

structures: Abrasive blasting using 

Staurite XL in containment at BP Oil 

Containment, Lima, Ohio. ECTB 183– 

13a. Cincinnati, OH: National Institute 

for Occupational Safety and Health. July. 

OSHA–2010–0034–0212 

[NIOSH, 1996] National Institute for 

Occupational Safety and Health. NIOSH 

ALERT: 1996. Preventing silicosis and 

deaths in construction workers. DHHS 

(NIOSH) Publication No. 96–112. 

OSHA–2010–0034–0391 

[NIOSH, 2001] National Institute for 

Occupational Safety and Health, Health 

Hazard Evaluation Report: 92–0311, CSX 

Transportation, Inc. Cincinnati, OH: 

National Institute for Occupational 

Safety and Health. January. OSHA– 

2010–0034–0884 

[NIOSH] National Institute for Occupational 

Safety and Health. (2002). NIOSH hazard 

review: Health effects of occupational 

exposure to respirable crystalline silica. 

Cincinnati, OH: U.S. Department of 

Health and Human Services, Public 

Health Service, Centers for Disease 

Control and Prevention, National 

Institute for Occupational Safety and 

Health. DHHS (NIOSH) Publication No. 

2002–129. OSHA–2010–0034–1110 

[NIOSH] National Institute for Occupational 

Safety and Health. (2007). National 

Occupational Respiratory Mortality 

System (NORMS). Morgantown, WV: 

U.S. Department of Health and Human 

Services, Public Health Service, Centers 

for Disease Control and Prevention, 

National Institute for Occupational 

Safety and Health, Division of 

Respiratory Disease Studies, 

Surveillance Branch. OSHA–2010–0034– 

0394 

[NIOSH, 2008–127] National Institute for 

Occupational Safety and Health. (2008). 

Workplace solutions—Water spray of 

hazardous dust when breaking concrete 

with a jackhammer. Available at: 

http://www.cdc.gov/niosh/docs/wpsolutions/2008-127/pdfs/2008-127.pdf 

OSHA–2010–0034–0838 

[NIOSH, 2008c] National Institute for 

Occupational Safety and Health. Workrelated lung disease surveillance report 

2007. Cincinnati, OH: U.S. Department 

of Health and Human Services, Public 

Health Service, Centers for Disease 

Control and Prevention, National 

Institute for Occupational Safety and 

Health. DHHS (NIOSH) Publication No. 

2008–143. OSHA–2010–0034–1308 

[NIOSH ECTB–208–11a] National Institute 

for Occupational Safety and Health. 

(1995). A laboratory comparison of 

conventional drywall sanding techniques 

versus commercially available controls. 

OSHA–2010–0034–0213 

[NIOSH, 2001–EPHB 247–19] Control 

technology for Ready-mix truck drum 

cleaning. File number EPHB 247–19. 

Cincinnati, OH: National Institute for 

Occupational Safety and Health. May. 

OSHA–2010–0034–0245 

[NIOSH, 2003–EPHB 282–11a] In-depth 

survey report of control of respirable 

dust and crystalline silica from breaking 

concrete with a jackhammer at Bishop 

Sanzari companies, North Bergen, NJ. 

Report number EPHB 282–11a. 

Cincinnati, OH: National Institute for 

Occupational Safety and Health. 

February. OSHA–2010–0034–0248 

[NIOSH EPHB 2004–282–11c–2] National 

Institute for Occupational Safety and 

Health. In-depth survey report of a water 

spray device for suppressing respirable 

and crystalline silica dust from 

jackhammers. OSHA–2010–0034–0867 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56483 

[NIOSH EPHB 2008–334–11a] National 

Institute for Occupational Safety and 

Health. In-depth survey: Preliminary 

evaluation of dust emissions control 

technology for dowel-pin drilling at 

Minnich Manufacturing, Mansfield, OH. 

OSHA–2010–0034–0871 

[NIOSH HETA 1997–94–0078–2660] National 

Institute for Occupational Safety and 

Health. Health hazard evaluation: Center 

to Protect Workers’ Rights, Washington, 

DC. OSHA–2010–0034–1335 

[NIOSH HETA 2001–92–0311] National 

Institute for Occupational Safety and 

Health. Health Hazard Evaluation 

Report: CSX Transportation, Inc. 

Cincinnati, OH: (92–0311). OSHA–2010– 

0034–0884 

[NIOSH HETA 2003–0275–2926] National 

Institute for Occupational Safety and 

Health, 2004. NIOSH health hazard 

evaluation report. U.S. Department of the 

Interior, Denver, CO. OSHA–2010–0034– 

1253 

[NIOSH, 2011] National Institute for 

Occupational Safety and Health. NIOSH 

Guideline—Application of Digital 

Radiography for the Detection and 

Classification of Pneumoconiosis. 

August 2011. DHHS (NIOSH) Publication 

No. 2011–198. http://www.cdc.gov/

niosh/docs/2011-198/ OSHA–2010– 

0034–1513 

[NIOSH] National Institute for Occupational 

Safety and Health. (2011a). Chest 

Radiography. B Reader Information for 

Medical Professionals. Web site accessed 

on May 16, 2013. http://www.cdc.gov/

niosh/topics/chestradiography/breaderinfo.html OSHA–2010–0034–1498 

[NIOSH] National Institute for Occupational 

Safety and Health. (2011b). Spirometry 

in the Occupational Setting—Spirometry 

Training Program. Web site accessed on 

May 16, 2013. http://www.cdc.gov/niosh/ 

topics/spirometry/training.html#a 

OSHA–2010–0034–1497 

[NISA]. National Industrial Sand Association. 

(2010). Occupational Health Program for 

Exposure to Crystalline Silica in the 

Industrial Sand Industry. Second 

Edition, April 2010. OSHA–2010–0034– 

1514 

[NJDHSS] New Jersey Department of Health 

and Senior Services, no date. NJ silicosis 

outreach and research alliance— 

Engineering controls for crystalline 

silica—Modifications to jackhammer 

spray dust control by NJ DOT. Available 

at: http://www.state.nj.us/health/

silicosis/documents/

njdotmodifications.pdf OSHA–2010– 

0034–0914 

[NTP] National Toxicology Program. (2000). 

Silica, Crystalline Silica (Respirable 

Size). In: Report on Carcinogens. 9th ed. 

Research Triangle Park. P. III–44 to III– 

46. OSHA–2010–0034–1417 

Nuyts GD, Van Vlem E, De Vos A, Daelemans 

RA, Rorive G, Elseviers MM, Schurgers 

M, Segaert M, D’Haese PC, and De Broe 

ME. (1995). Wegener granulomatosis is 

associated to exposure to silicon 

compounds: A case-control study. 

Nephrol Dial Transplant 10:1162–1165. 

OSHA–2010–0034–0397 

[OSHA] 3362–05 Occupational Safety and 

Health Administration. (2009). 

Controlling Silica Exposures in 

Construction (OSHA 3362–05) OSHA– 

2010–0034–0933 

[OSHA] Occupational Safety and Health 

Administration. (2003). Report of the 

Small Business Advocacy Review Panel 

On the Draft OSHA Standards for Silica. 

December 19, 2003. OSHA–2010–0034– 

0937 

[OSHA] Occupational Safety and Health 

Administration. (2006). Final Economic 

and Regulatory Flexibility Analysis for 

OSHA’s Final Standard for Occupational 

Exposure to Hexavalent Chromium; 

Docket H054A, Exhibit 49. OSHA–2010– 

0034–0513 

[OSHA] Occupational Safety and Health 

Administration. (2010). OSHA Training 

Standards Policy Statement. April 28, 

2010. http://www.osha.gov/dep/

standards-policy-statement-memo-04-28- 

10.html OSHA–2010–0034–1499 

[OSHA] Occupational Safety and Health 

Administration. (2013). Supplemental 

Literature Review of Epidemiological 

Studies on Lung Cancer Associated with 

Exposure to Respirable Crystalline Silica. 

Ogawa S, Imai H, and Ikeda M. (2003). A 40- 

year follow-up of whetstone cutters on 

silicosis. Ind Health 41:69–76. OSHA– 

2010–0034–0398 

[OMB] Office of Management and Budget, 

Executive Office of the President. (2004). 

Final Information Quality Bulletin for 

Peer Review, December 15, 2004. 

Available at http://www.whitehouse.gov/ 

omb/memoranda/fy2005/m05-03.pdf. 

OSHA–2010–0034–1336 

[OMB] Office of Management and Budget. 

(2003). Circular A–4, Regulatory 

Analysis, September 17, 2003. http://

www.whitehouse.gov/sites/default/files/

omb/assets/regulatory_matters_pdf/a4.pdf OSHA–2010–0034–1493 

Osorio AM, Thun MJ, Novak RF, Van Cura 

EJ, and Avner ED. (1987). Silica and 

glomerulonephritis: Case report and 

review of the literature. Am J Kidney Dis 

9:224–230. OSHA–2010–0034–0400 

Pan G, Takahashi K, Feng Y, Liu L, Liu T, 

Zhang S, Liu N, Okubo T, and Goldsmith 

DF. (1999). Nested case-control study of 

esophageal cancer in relation to 

occupational exposure to silica and other 

dusts. Am J Ind Med 35:272–280. 

OSHA–2010–0034–0403 

Park R, Rice F, Stayner L, Smith R, Gilbert 

S, and Checkoway H. (2002). Exposure to 

crystalline silica, silicosis, and lung 

disease other than cancer in 

diatomaceous earth industry workers: A 

quantitative risk assessment. Occup 

Environ Med 59:36–43. OSHA–2020– 

0034–0405 

Parks CG, Conrad K, and Cooper GS. (1999). 

Occupational exposure to crystalline 

silica and autoimmune disease. Environ 

Health Perspect 107:793–802. OSHA– 

2010–0034–0406 

Pannel and Grogin (2000). Quantifying the 

exposure of heavy-equipment operators 

to respirable crystalline silica dust. 

Environmental Health. OSHA–2010– 

0034–0952 

Pelucchi C, Pira E, Piolatto G, Coggiola M, 

Carta P, and La Vecchia C. (2006). 

Occupational silica exposure and lung 

cancer risk: A review of epidemiological 

studies 1996–2005. Ann Oncol 17:1039– 

1050. OSHA–2010–0034–0408 

Plinke MA, Maus R, and Leith D. (1992). 

Experimental examination of factors that 

affect dust generation by using Heubach 

and MRI testers. American Industrial 

Hygiene Association Journal 53(5):325– 

330. OSHA–2010–0034–0957 

Popendorf W, Pryor A, Wenk H. (1982) 

Mineral dust in manual harvest 

operations. Ann Am Conf Gov Ind Hyg; 

2: 101–15. As cited in Swanepoel et al. 

(2010). OSHA–2010–0034–1491 

Porcelain Industries (2004a). Personal 

communication between Jim Nix, 

manager of safety and environmental 

compliance at Porcelain Industries, Inc., 

Dickson, Tennessee, and Eastern 

Research Group, Inc. September 1. 

OSHA–2010–0034–1277 

Porcelain Industries (2004b). Personal 

communication between Jim Nix, 

manager of safety and environmental 

compliance at Porcelain Industries, Inc., 

Dickson, Tennessee, and Eastern 

Research Group, Inc. September 14. 

OSHA–2010–0034–0960 

Porter DW, Barger M, Robinson VA, Leonard 

SS, Landsittel D, and Castronova V. 

(2002). Comparison of low doses of aged 

and freshly fractured silica on 

pulmonary inflammation and damage in 

the rat. Toxicology 175:63–71. OSHA– 

2010–0034–1114 

Pukkala E, Guo J, Kyyro ̈nen P, Lindbohm ML, 

Sallme ́n M, and Kauppinen T. (2005). 

National job-exposure matrix in analyses 

of census-based estimates of 

occupational cancer risk. Scand J Work 

Environ Health 31:97–107. OSHA–2010– 

0034–0412 

Rando RJ, Shi R, Hughes JM, Weill H, 

McDonald AD, and McDonald JC. (2001). 

Cohort mortality study of North 

American industrial sand workers. III. 

Estimation of past and present exposures 

to respirable crystalline silica. Ann 

Occup Hyg 45:209–216. OSHA–2010– 

0034–0415 

Rapiti E, Sperati A, Miceli M, Forastiere F, 

Di Lallo D, Cavariani F, Goldsmith DF, 

and Perucci CA. (1999). End stage renal 

disease among ceramic workers exposed 

to silica. Occup Environ Med 56:559– 

561. OSHA–2010–0034–1245 

Rappaport SM, Goldberg M, Susi P, and 

Herrick RF. (2003). Excessive exposure 

to silica in the U.S. construction 

industry. Annals of Occupational 

Hygiene 47(2):111–120. OSHA–2010– 

0034–0962 

Rastogi SK, Gupta BN, Chandra H, Mathur N, 

Mahendra PN, and Husain T. (1991). A 

study of the prevalence of respiratory 

morbidity among agate workers. Int Arch 

Occup Environ Health 63:21–26. OSHA– 

2010–0034–1258 

Reed WR, Listak JM, Page SJ and Organiscak 

JA. (2008). Summary of NIOSH research 

completed on dust control methods for 

surface and underground drilling. 

Pittsburgh, PA: National Institute for 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56484 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

Occupational Safety and Health. OSHA– 

2010–0034–0967 

Rees, D and Murray J. (2007). Silica, silicosis 

and tuberculosis. Int J Tuberc Lung Dis. 

11: 474–484. OSHA–2010–0334–1337 

Reid PJ and Sluis-Cremer GK. (1996). 

Mortality of white South African gold 

miners. Occup Environ Med 53:11–16. 

OSHA–2010–0034–0416 

Rice FL, Park R, Stayner L, Smith R, Gilbert 

S, and Checkoway H. (2001). Crystalline 

silica exposure and lung cancer mortality 

in diatomaceous earth industry workers: 

A quantitative risk assessment. Occup 

Environ Med 58:38–45. OSHA–2010– 

0034–1118 

Rice FL and Stayner LT (1995). Assessment 

of silicosis risk for occupational 

exposure to crystalline silica. Scand J 

Work Environ Health 21 (suppl. 2):87– 

90. OSHA–2010–0034–0418 

Rosenman KD, Moore-Fuller M, and Reilly 

MJ. (2000). Kidney disease and silicosis. 

Nephron 85:14–19. OSHA–2010–0034– 

1120 

Rosenman KD, Moore-Fuller M, Reilly MJ. 

(1999). Connective tissue disease and 

silicosis. Am J Ind Med 35:375–81. 

OSHA–2010–0034–0421 

Rosenman KD, Reilly MJ, and Henneberger 

PK. (2003). Estimating the total number 

of newly-recognized silicosis cases in the 

United States. Am J Ind Med 44:141–147. 

OSHA–2010–0034–0420 

Rosenman KD, Reilly MJ, Kalinowski DJ, and 

Watt FC. (1997). Occupational and 

environmental lung disease: Silicosis in 

the 1990s. Chest 111:779–786. OSHA– 

2010–0034–0422 

Rosenman KD, Reillly MJ, Rice C, Hertzberg 

V, Tseng C, Anderson HA (1996). 

Silicosis among foundry workers. 

Implication for the need to revise the 

OSHA standard. Am J Epidemiol 

144:890–900. OSHA–2010–0034–0423 

Rosenman KD and Zhu Z. (1995). 

Pneumoconiosis and associated medical 

conditions. Am J Ind Med 27:107–113. 

OSHA–2010–0034–0424 

Ross M and Murray J. (2004). Occupational 

respiratory disease in mining. Occup 

Med 54:304–10 OSHA–2010–0034–1338 

Rutstein DD, Mullan RJ, Frazier TM, Halperin 

WE, Melius JM, and Sestito JP. (1983). 

Sentinel health events (occupational): A 

basis for physician recognition and 

public health surveillance. Am J Public 

Health 73:1054–1062. OSHA–2010– 

0034–0425 

Samet JM, Young RA, Morgan MV, Humble 

CG, Epler GR, and McLoud TC. (1984). 

Prevalence of respiratory abnormalities 

in New Mexico uranium miners. Health 

Phys 46:361–370. OSHA–2010–0034– 

0427 

Sanderson WT, Steenland K, and Deddens 

JA. (2000). Historical respirable quartz 

exposures of industrial sand workers: 

1946–1996. Am J Ind Med 38:389–398. 

OSHA–2010–0034–0429 

Schins RP. (2002). Mechanisms of 

genotoxicity of particles and fibers. Inhal 

Toxicol. 14:57–78. OSHA–2010–0034– 

1339 

Seixas NS, Heyer NJ, Welp EA, and 

Checkoway H. (1997). Quantification of 

historical dust exposures in the 

diatomaceous earth industry. Ann Occup 

Hyg 41:591–604. OSHA–2010–0034– 

0431 

Selikoff IJ. (1978). Carcinogenic potential of 

silica compounds. In: Bendz G and 

Lindqvist I, editors. Biochemistry of 

silicon and related problems. New York: 

Plenum Press. p. 311–336. OSHA–2010– 

0034–0432 

Sherson D and Lander F. (1990). Morbidity 

of pulmonary TB among silicotic and 

nonsilicotic foundry workers in 

Denmark. J Occup Med. 32:110–113. 

OSHA–2010–0034–0434 

Shoemaker DA, Pretty JR, Ramsey DM, 

McLaurin JL, Khan A, Teass AW, 

Castronova V, Pailes WH, Dalal NS, 

Miles PR, Bowman L, Leonard S, 

Shumaker J, Vallyathan V, and Pack D. 

(1995). Particle activity and in vivo 

pulmonary response to freshly milled 

and aged alpha-quartz. Scan J Work 

Environ Health 21:15–18. OSHA–2010– 

0034–0437 

Simcox N, Lofgren D, Leons J, and Camp J. 

(1999). Silica exposure during granite 

countertop fabrication. Applied 

Occupational and Environmental 

Hygiene. 577–582. OSHA–2010–0034– 

1146 

Sluis-Cremer GK, Hessel PA, Hnizdo E, 

Churchill AR, and Zeiss EA. (1985). 

Silica, silicosis and progressive systemic 

sclerosis. Br J Ind Med 41:838–843. 

OSHA–2010–0034–0439 

Sluis-Cremer GK, Walters LG, and Sichel HS. 

(1967). Chronic bronchitis in miners and 

non-miners: An epidemiological survey 

of a community in the gold-mining area 

in the Transvaal. Br J Ind Med 24:1–12. 

OSHA–2010–0034–0440 

Smandych RS, Thomson M, and Goodfellow 

H. (1998). Dust control for material 

handling operations: a systematic 

approach. American Industrial Hygiene 

Association Journal 59(2):139–146. 

OSHA–2010–0034–1147 

Smith DK. (1998). Opal, cristobalite, and 

tridymite: Noncrystallinity versus 

crystallinity, nomenclature of the silica 

minerals and bibliography. Powder 

Diffraction 13(1):2–19. OSHA–2010– 

0034–1424 

Stayner L. (2007). Silica and lung cancer: 

When is enough evidence enough? 

Epidemiology 18:23–24. OSHA–2010– 

0034–0446 

Steenland K. (2005a). Silica: de ́ja` vu all over 

again? Occup Environ Med 62:430–432. 

OSHA–2010–0034–1313 

Steenland K. (2005b). One agent, many 

diseases: Exposure-response data and 

comparative risks of different outcomes 

following silica exposure. Am J Ind Med 

48:16–23. OSHA–2010–0034–1123 

Steenland K. (2010). Personal 

communication with William Perry, 

Directorate of Standards and Guidance, 

Washington, DC. OSHA–2010–0034– 

1312 

Steenland K, Attfield M, and Mannejte A. 

(2002a). Pooled analyses of renal disease 

mortality and crystalline silica exposure 

in three cohorts. Ann Occup Hyg 46:4– 

9. OSHA–2010–0034–0448 

Steenland K and Brown D. (1995a). Mortality 

study of gold miners exposed to silica 

and nonasbestiform amphibole minerals: 

An update with 14 more years of followup. Am J Ind Med 27:217–229. OSHA– 

2010–0034–0450 

Steenland K and Brown D. (1995b). Silicosis 

among gold-miners: An exposureresponse analysis. Am J Pub Health 

85:1372–1377. OSHA–2010–0034–0451 

Steenland K and Deddens JA. (2002). 

Response to the letter from Dr. Ulm. 

Cancer Causes Control 13:779–785. 

OSHA–2010–0034–1124 

Steenland K, Mannetje A, Boffetta P, Stayner 

L, Attfield M, Chen J, Dosemeci M, 

DeKlerk N, Hnizdo E, Koskela R, and 

Checkoway H. (2001a). Noncrystallinity 

versus crystallinity, nomenclature of the 

silica minerals and bibliography: An 

IARC multi-centric study. Cancer Causes 

Control 12:773–784. OSHA–2010–0034– 

0452 

Steenland K and Sanderson W. (2001). Lung 

cancer among industrial sand workers 

exposed to crystalline silica. Am J 

Epidemiol 153:695–703. OSHA–2010– 

0034–0455 

Steenland K, Sanderson W, and Calvert GM. 

(2001b). Kidney disease and arthritis in 

a cohort study of workers exposed to 

silica. Epidemiology 12:405–412. OSHA– 

2010–0034–0456 

Steenland NK, Thun MJ, Ferguson CW, and 

Port FK. (1990). Occupational and other 

exposures associated with male endstage renal disease: A case/control study. 

Am J Public Health 80:153–157. OSHA– 

2010–0034–1125 

Stern F, Lehman E, and Ruder A. (2001). 

Mortality among unionized construction 

plasterers and cement masons. Am J Ind 

Med 39:373–388. OSHA–2010–0034– 

0458 

Suhr H, Bang B, and Moen BE. (2003). 

Respiratory health among quartzexposed workers—a problem even today. 

Occup Med 53:406–407. OSHA–2010– 

0034–0462 

Sun J, Weng D, Jin C, Yan B, Xu G, Jin B, 

Xia S, and Chen J. (2008). The value of 

high resolution computed tomography in 

the diagnostics of small opacities and 

complications of silicosis in mine 

machinery manufacturing workers, 

compared to radiography. J Occup 

Health 50:400–405. OSHA–2010–0034– 

0463 

Sunstein, C., 2004. Valuing Life: A Plea for 

Disaggregation, Duke Law Journal 54: 

385–445. OSHA–2010–0034–1523 

Swanepoel AJ, Rees D, Renton K, Swanepoel 

C, Kromhout H, Gardiner K. (2010) 

Quartz exposure in agriculture: literature 

review and South African survey. Ann 

Occup Hyg. 54(3):281–92. OSHA–2010– 

0034–1491 

Szeinuk J, Beckett WS, Clark N, Hailoo WL. 

(2000). Medical evaluation for respirator 

use. Am J Industr Med. 37:142–157. 

OSHA–2010–0034–1340 

Talini D, Paggiaro PL, Falaschi F, Battolla L, 

Carrara M, Petrozzino M, Begliomini E, 

Bartolozzi C, Giuntini C. (1995). Chest 

radiography and high resolution 

computed tomography in the evaluation 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56485 

of workers exposed to silica dust: 

relation with functional findings. Occup 

Environ Med. 52(4):262–7. OSHA–2010– 

0034–1515 

teWaterNaude JM, Ehrlich RI, Churchyard GJ, 

Pemba L, Dekker K, Vermeis M, White 

NW., Thompson ML, and Myers JE. 

(2006). Tuberculosis and silica exposure 

in South African gold miners. Occup 

Environ Med 63:187–192. OSHA–2010– 

0034–0465 

Toxichemica, Inc. (2004). Silica exposure: 

Risk assessment for lung cancer, 

silicosis, and other diseases. Draft final 

report prepared under Department of 

Labor Contract No. J–9–F–0–0051. 

Gaithersburg, Maryland, December 7, 

2004. OSHA–2010–0034–0469 

Thaler, R., and S. Rosen, 1976. ‘‘The Value 

of Saving a Life: Evidence from the Labor 

Market,’’ in Household Production and 

Consumption, N E. Terleckyj (ed.), New 

York: Columbia University Press, 1976, 

pp. 265–298. OSHA–2010–0034–1520 

Theriault GP, Burgess WA, DiBerardinis LJ, 

and Peters JM. (1974a). Dust exposure in 

the Vermont granite sheds. Arch Environ 

Health 28:12–17. OSHA–2010–0034– 

0466 

Theriault GP, Peters JM, and Fine LJ. (1974b). 

Pulmonary function in granite shed 

workers of Vermont. Arch Environ 

Health 28:18–22. OSHA–2010–0034– 

0467 

Thorpe A, Ritchie AS, Gibson MJ, and Brown 

RC. (1999). Measurements of the 

effectiveness of dust control on cut-off 

saws used in the construction industry. 

Annals of Occupational Hygiene 43(7): 

1443–1456. OSHA–2010–0034–1181 

Tsuda T, Babazono A,Yamamoto E, Mino Y, 

and Matsuoka H. (1997). A meta-analysis 

on the relationship between 

pneumoconiosis and lung cancer. J 

Occup Health 39:285–294. OSHA–2010– 

0034–1127 

Tsuda T, Mino Y, Babazono A, Shigemi J, 

Otsu T, and Yamamoto E. (2001). A casecontrol study of the relationships among 

silica exposure, gastric cancer, and 

esophageal cancer. Am J Ind Med 39:52– 

57. OSHA–2010–0034–0470 

U.S. Bureau of Economic Analysis (BEA, 

2010). National Income and Product 

Accounts Table: Table 1.1.9. Implicit 

Price Deflators for Gross Domestic 

Product [Index numbers, 2005=100]. 

Revised May 27, 2010. http://

www.bea.gov/national/nipaweb/

TableView.asp?SelectedTable=13

&Freq=Qtr&First

Year=2006&LastYear=200 OSHA–2010– 

0034–1204 

U.S. Environmental Protection Agency, 2000 

(EPA, 2000). SAB Report on EPA’s White 

Paper Valuing the Benefits of Fatal 

Cancer Risk Reduction. EPA–SAB– 

EEAC–00–013. OSHA–2010–0034–0652 

U.S. Environmental Protection Agency, 2003 

(EPA, 2003). National Primary Drinking 

Water Regulations; Stage 2 Disinfectants 

and Disinfection Byproducts Rule; 

National Primary and Secondary 

Drinking Water Regulations; Approval of 

Analytical methods for Chemical 

Contaminants; Proposed Rule, August 

18, 2003. Federal Register, Volume 68, 

Number 159. OSHA–2010–0034–0657 

U.S. Environmental Protection Agency, 2008 

(EPA, 2008). Office of Air Quality 

Planning and Standards, Health and 

Environmental Impacts Division, Air 

Benefit and Cost Group, Final Ozone 

NAAQS Regulatory Impact Analysis, 

March. OSHA–2010–0034–0661 

U.S. Internal Revenue Service (IRS, 2007). 

Corporation Source Book, 2006. http://

www.irs.gov/taxstats/bustaxstats/article/

0,,id=149687,00.html, Accessed by ERG, 

2009. OSHA–2010–0034–0751 

U.S. Office of Management and Budget, 2003 

(OMB, 2003). Circular A–4, Regulatory 

Analysis, September 17, 2003. Available 

at: http://www.whitehouse.gov/omb/

circulars/a004/a-4.pdf. OSHA–2010– 

0034–0931 

U.S. Office of Technology Assessment (OTA, 

1995). Gauging Control Technology and 

Its Regulatory Impacts in Occupational 

Safety and Health. Washington, DC: US 

Congress, Office of Technology 

Assessment, 1995; Publication Number 

OTA–ENV–635. OSHA–2010–0034–0947 

Vallyathan V, Castranova V, Pack D, Leonard 

S, Shumaker J, Hubbs AF, Shoemaker 

DA, Ramsey DM, Pretty JR, McLaurin JL, 

Khan A, and Teass A. (1995). Freshly 

fractured quartz inhalation leads to 

enhanced lung injury and inflammation. 

Potential role of free radicals. Am J 

Respir Crit Care Med 152:1003–1009. 

OSHA–2010–0034–1128 

Van Rooij GM and Klaase J. (2007). Effect of 

additive in spray water of asphalt milling 

machine on the dust and quartz exposure 

of workers. Tijdschrift voor toegepaste 

Arbowetenschap. Nr 1 en 2. Pages 3–5. 

OSHA–2010–0034–1216 

Viscusi W and Aldy J. (2003). The Value of 

a Statistical Life: A Critical Review of 

Market Estimates Throughout the World, 

Journal of Risk and Uncertainty, (27:5– 

76). OSHA–2010–0034–1220 

Wagner MM, Wagner JC, Davies R, and 

Griffiths DM. (1980). Silica-induced 

malignant histiocytic lymphoma: 

Incidence linked with strain of rat and 

type of silica. Br J Cancer 41:908–917. 

OSHA–2010–0034–0476 

Wang ML, Avashia BH, Wood J, Petsonk EL. 

(2009). Excessive longitudinal FEV1 

decline and risks to future health: a casecontrol study. Am J Ind Med. 

52(12):909–15. OSHA–2010–0034–1516 

Wang X, Yano E, Nonaka K, Wang M, and 

Wang Z. (1997). Respiratory impairments 

due to dust exposure: A comparative 

study among workers exposed to silica, 

asbestos, and coalmine dust. Am J Ind 

Med 31:495–502. OSHA–2010–0034– 

0478 

Westerholm P. (1980). Silicosis observations 

on a case register. Scand J Work Environ 

Health 6:1–86. OSHA–2010–0034–0484 

Wiles FJ, Baskind E, Hessel PA, 

Bezuidenhout B, and Hnizdo E. (1992). 

Lung function in silicosis. Int Arch 

Occup Environ Health 63:387–391. 

OSHA–2010–0034–0485 

Williams DR and Sam K. (1999). ‘‘Illinois 

Ready-Mixed Concrete Association 

Industrial Hygiene Study: October 1997 

through June 1999.’’ Illinois Department 

of Commerce and Community Affairs, 

Illinois On-Site Consultation Program, 

100 West Randolph Street, Chicago, 

Illinois. [Unpublished Data] OSHA– 

2010–0034–1356 

Windau J, Rosenman K, Anderson H, 

Hanrahan L, Rudolph L, Stanbury M, 

and Stark A. (1991). The identification of 

occupational lung disease from hospital 

discharge data. J Occup Med 33:1060– 

1066. OSHA–2010–0034–0487 

Weiderpass E, Vainio H, Kauppinen T, 

Vasama-Neuvonen K, Partanen T, and 

Pukkala E. (2003). Occupational 

exposures and gastrointestinal cancers 

among Finnish women. J Occup Environ 

Med 45:305–315. OSHA–2010–0034– 

0480 

Wernli KJ, Fitzgibbons ED, Ray RM, Gao DL, 

Li W, Seixas NS, Camp JE, Astrakianakis 

G, Feng Z, Thomas DB, and Checkoway 

H. (2006). Occupational risk factors for 

esophageal and stomach cancers among 

female textile workers in Shanghai, 

China. Am J Epidemiol 163:717–725. 

OSHA–2010–0034–0482 

Wiles FJ, Baskind E, Hessel PA, 

Bezuidenhout B, and Hnizdo E. (1992). 

Lung function in silicosis. Int Arch 

Occup Environ Health 63:387–391. 

OSHA–2010–0034–0485 

Wiles FJ and Faure MH. (1977). Chronic 

obstructive lung disease in gold miners. 

In: Walton WH, editor. Inhaled particles 

IV, Part 2. Oxford: Pergamon Press. p. 

727–35. OSHA–2010–0034–0486 

Winter PD, Gardner MJ, Fletcher AC, and 

Jones RD. (1990). A mortality follow-up 

study of pottery workers: Preliminary 

findings on lung cancer. IARC Sci Publ 

97:83–94. OSHA–2010–0034–0488 

Wright JL, Harrison N, Wiggs B, and Churg 

A. (1988). Quartz but not iron oxide 

causes air-flow obstruction, emphysema, 

and small airways lesions in the rat. Am 

Rev Respir Dis 138:129–135. Cited in: 

Hnizdo E and Vallyathan V. 2003. 

Chronic obstructive pulmonary disease 

due to occupational exposure to silica 

dust: A review of epidemiological and 

pathological evidence. Occup Environ 

Med 60:237–243. OSHA–2010–0034– 

0489 

[WHO]. World Health Organization (1996). 

Screening and surveillance of workers 

exposed to mineral dust. OSHA–2010– 

0034–1517 

Wyndham CH, Bezuidenhout BN, Greenacre 

MJ, and Sluis-Cremer GK. (1986). 

Mortality of middle aged white South 

African gold miners. Br J Ind Med 

43:677–684. OSHA–2010–0034–0490 

Xu Z, Pan GW, Liu LM, Brown LM, Guan DX, 

Xiu Q, Sheng JH, Stone BJ, Dosemeci M, 

Fraumeni JF, Jr., and Blot WJ. (1996a). 

Cancer risks among iron and steel 

workers in Anshan, China, part I: 

Proportional mortality ratio analysis. Am 

J Ind Med 30:1–6. OSHA–2010–0034– 

0491 

Yang H, Yang L, Zhang J, and Chen J. (2006). 

Natural course of silicosis in dustexposed workers. J Huazhong University 

of Science and Technology [Med Sci] 26: 

257–260. OSHA–2010–0034–1260 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56486 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

Young-Corbett DE and Nussbaum MA. 

(2009a). Dust control effectiveness of 

drywall sanding tools. Journal of 

Occupational and Environmental 

Hygiene 6:385–389. OSHA–2010–0034– 

1239 

Young-Corbett DE and Nussbaum MA. 

(2009b). Dust control technology usage 

patterns in the drywall finishing 

industry. Journal of Occupational and 

Environmental Hygiene 6:315–323. 

OSHA–2010–0034–1240 

Yu ITS, Tse LA, Wong TW, Leung CC, Tam 

CM, and Chan ACK. (2005). Further 

evidence for a link between silica dust 

and esophageal cancer. Int J Cancer 

114:479–483. OSHA–2010–0034–1135 

List of Subjects in 29 CFR Parts 1910, 

1915, and 1926 

Cancer, Chemicals, Cristobalite, 

Crystalline silica, Hazardous substances, 

Health, Occupational safety and health, 

Quartz, Reporting and recordkeeping 

requirements, Silica, Tridymite. 

XVIII. Authority and Signature 

This document was prepared under 

the direction of David Michaels, Ph.D., 

MPH, Assistant Secretary of Labor for 

Occupational Safety and Health, U.S. 

Department of Labor, 200 Constitution 

Avenue NW., Washington, DC 20210. 

The Agency issues the proposed 

sections under the following authorities: 

sections 4, 6, and 8 of the Occupational 

Safety and Health Act of 1970 (29 U.S.C. 

653, 655, 657); section 107 of the 

Contract Work Hours and Safety 

Standards Act (the Construction Safety 

Act) (40 U.S.C. 333); section 41 of the 

Longshore and Harbor Worker’s 

Compensation Act (33 U.S.C. 941); 

Secretary of Labor’s Order No. 4–2010 

(75 FR 55355, September 10, 2010); and 

29 CFR part 1911. 

Signed at Washington, DC, on August 23, 

2013. 

David Michaels, 

Assistant Secretary of Labor for Occupational 

Safety and Health. 

Amendments to Standards 

For the reasons set forth in the 

preamble, OSHA proposes to amend 

chapter XVII of title 29, parts 1910, 

1915, and 1926, of the Code of Federal 

Regulations as follows: 

PART 1910—OCCUPATIONAL SAFETY 

AND HEALTH STANDARDS 

Subpart Z—[AMENDED] 

■ 1. The authority citation for subpart Z 

of part 1910 is revised to read as 

follows: 

Authority: Secs. 4, 6, 8 of the Occupational 

Safety and Health Act of 1970 (29 U.S.C. 653, 

655, 657); Secretary of Labor’s Order No. 8– 

76 (41 FR 25059), 9–83 (48 FR 35736), 1–90 

(55 FR 9033), 6–96 (62 FR 111), 3–2000 (65 

FR 50017), 5–2002 (67 FR 65008), 5–2007 (72 

FR 31159), or 4–2010 (75 FR 55355), as 

applicable; and 29 CFR part 1911. All of 

subpart Z issued under section 6(b) of the 

Occupational Safety and Health Act of 1970, 

except those substances that have exposure 

limits listed in Tables Z–1, Z–2, and Z–3 of 

29 CFR 1910.1000. The latter were issued 

under section 6(a) (29 U.S.C. 655(a)). 

Section 1910.1000, Tables Z–1, Z–2 and Z– 

3 also issued under 5 U.S.C. 553, but not 

under 29 CFR part 1911 except for the 

arsenic (organic compounds), benzene, 

cotton dust, and chromium (VI) listings. 

Section 1910.1001 also issued under 

section 107 of the Contract Work Hours and 

Safety Standards Act (40 U.S.C. 3704) and 5 

U.S.C. 553. 

Section 1910.1002 also issued under 5 

U.S.C. 553, but not under 29 U.S.C. 655 or 

29 CFR part 1911. 

Sections 1910.1018, 1910.1029, and 

1910.1200 also issued under 29 U.S.C. 653. 

Section 1910.1030 also issued under Pub. L. 

106–430, 114 Stat. 1901. 

■ 2. In § 1910.1000, Table Z–1—Limits 

for Air Contaminants, remove ‘‘Silica, 

crystalline cristobalite, respirable dust’’, 

‘‘Silica, crystalline quartz, respirable 

dust’’, ‘‘Silica, crystalline tripoli (as 

quartz), respirable dust’’, and ‘‘Silica, 

crystalline tridymite, respirable dust’’; 

and add ‘‘Silica, crystalline, respirable 

dust; see 1910.1053’’ in alphabetical 

order, to read as follows: 

§ 1910.1000 Air contaminants. 

* * * * * 

TABLE Z–1—LIMITS FOR AIR CONTAMINANTS

Substance CAS No. (c) ppm (a) 1 mg/m3(b)1 Skin designation 

*******

Silica, crystalline, respirable dust; see 1910.1053.

*******

* * * * * ■ 3. In § 1910.1000, Table Z–3—Mineral 

Dusts, the entry ‘‘Silica:’’ is revised to 

read as follows: 

§ 1910.1000 Air contaminants. 

* * * * * 

TABLE Z–3—MINERAL DUSTS

Substance mppcf a mg/m3

Silica: 

Amorphous, including natural diatomaceous earth .................................................................................. 20 80 mg/m3

%SiO2

* * * * * * * 

■ 4. A new § 1910.1053 is added, to read 

as follows: 

§ 1910.1053 Respirable crystalline silica. 

(a) Scope and application. (1) This 

section applies to all occupational 

exposures to respirable crystalline 

silica, except: 

(2) Construction work as defined in 29 

CFR 1910.12(b) and covered under 29 

CFR part 1926; and 

(3) Agricultural operations covered 

under 29 CFR part 1928. 

(b) Definitions. For the purposes of 

this section the following definitions 

apply: 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56487 

Action level means a concentration of 

airborne respirable crystalline silica of 

25 micrograms per cubic meter of air (25 

mg/m3), calculated as an 8-hour timeweighted average (TWA). 

Assistant Secretary means the 

Assistant Secretary of Labor for 

Occupational Safety and Health, U.S. 

Department of Labor, or designee. 

Competent person means one who is 

capable of identifying existing and 

predictable respirable crystalline silica 

hazards in the surroundings or working 

conditions and who has authorization to 

take prompt corrective measures to 

eliminate them. 

Director means the Director of the 

National Institute for Occupational 

Safety and Health (NIOSH), U.S. 

Department of Health and Human 

Services, or designee. 

Employee exposure means the 

exposure to airborne respirable 

crystalline silica that would occur if the 

employee were not using a respirator. 

High-efficiency particulate air [HEPA] 

filter means a filter that is at least 99.97 

percent efficient in removing monodispersed particles of 0.3 micrometers 

in diameter. 

Objective data means information 

such as air monitoring data from 

industry-wide surveys or calculations 

based on the composition or chemical 

and physical properties of a substance 

demonstrating employee exposure to 

respirable crystalline silica associated 

with a particular product or material or 

a specific process, operation, or activity. 

The data must reflect workplace 

conditions closely resembling the 

processes, types of material, control 

methods, work practices, and 

environmental conditions in the 

employer’s current operations. 

Physician or other licensed health 

care professional [PLHCP] means an 

individual whose legally permitted 

scope of practice (i.e., license, 

registration, or certification) allows him 

or her to independently provide or be 

delegated the responsibility to provide 

some or all of the particular health care 

services required by paragraph (h) of 

this section. 

Regulated area means an area, 

demarcated by the employer, where an 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica exceeds, or can reasonably be 

expected to exceed, the PEL. 

Respirable crystalline silica means 

airborne particles that contain quartz, 

cristobalite, and/or tridymite and whose 

measurement is determined by a 

sampling device designed to meet the 

characteristics for respirable-particlesize-selective samplers specified in the 

International Organization for 

Standardization (ISO) 7708:1995: Air 

Quality—Particle Size Fraction 

Definitions for Health-Related 

Sampling. 

This section means this respirable 

crystalline silica standard, 29 CFR 

1910.1053. 

(c) Permissible exposure limit (PEL). 

The employer shall ensure that no 

employee is exposed to an airborne 

concentration of respirable crystalline 

silica in excess of 50 mg/m3, calculated 

as an 8-hour TWA. 

(d) Exposure assessment. (1) General. 

(i) Each employer covered by this 

section shall assess the exposure of 

employees who are or may reasonably 

be expected to be exposed to respirable 

crystalline silica at or above the action 

level. 

(ii) The employer shall determine 

employee exposures from breathing 

zone air samples that reflect the 8-hour 

TWA exposure of each employee. 

(iii) The employer shall determine 8- 

hour TWA exposures on the basis of one 

or more air samples that reflect the 

exposures of employees on each shift, 

for each job classification, in each work 

area. Where several employees perform 

the same job tasks on the same shift and 

in the same work area, the employer 

may sample a representative fraction of 

these employees in order to meet this 

requirement. In representative sampling, 

the employer shall sample the 

employee(s) who are expected to have 

the highest exposure to respirable 

crystalline silica. 

(2) Initial exposure assessment. (i) 

Except as provided for in paragraph 

(d)(2)(ii) of this section, each employer 

shall perform initial monitoring of 

employees who are, or may reasonably 

be expected to be, exposed to airborne 

concentrations of respirable crystalline 

silica at or above the action level. 

(ii) The employer may rely on existing 

data to satisfy this initial monitoring 

requirement where the employer: 

(A) Has monitored employee 

exposures after [INSERT DATE 12 

MONTHS PRIOR TO EFFECTIVE DATE 

OF FINAL RULE] under conditions that 

closely resemble those currently 

prevailing, provided that such 

monitoring satisfies the requirements of 

paragraph (d)(5)(i) of this section with 

respect to analytical methods employed; 

or 

(B) Has objective data that 

demonstrate that respirable crystalline 

silica is not capable of being released in 

airborne concentrations at or above the 

action level under any expected 

conditions of processing, use, or 

handling. 

(3) Periodic exposure assessments. If 

initial monitoring indicates that 

employee exposures are below the 

action level, the employer may 

discontinue monitoring for those 

employees whose exposures are 

represented by such monitoring. If 

initial monitoring indicates that 

employee exposures are at or above the 

action level, the employer shall assess 

employee exposures to respirable 

crystalline silica either under the fixed 

schedule prescribed in paragraph 

(d)(3)(i) of this section or in accordance 

with the performance-based 

requirement prescribed in paragraph 

(d)(3)(ii) of this section. 

(i) Fixed schedule option. (A) Where 

initial or subsequent exposure 

monitoring reveals that employee 

exposures are at or above the action 

level but at or below the PEL, the 

employer shall repeat such monitoring 

at least every six months. 

(B) Where initial or subsequent 

exposure monitoring reveals that 

employee exposures are above the PEL, 

the employer shall repeat such 

monitoring at least every three months. 

(C) The employer shall continue 

monitoring at the required frequency 

until at least two consecutive 

measurements, taken at least 7 days 

apart, are below the action level, at 

which time the employer may 

discontinue monitoring for that 

employee, except as otherwise provided 

in paragraph (d)(4) of this section. 

(ii) Performance option. The employer 

shall assess the 8-hour TWA exposure 

for each employee on the basis of any 

combination of air monitoring data or 

objective data sufficient to accurately 

characterize employee exposures to 

respirable crystalline silica. 

(4) Additional exposure assessments. 

The employer shall conduct additional 

exposure assessments as required under 

paragraph (d)(3) of this section 

whenever a change in the production, 

process, control equipment, personnel, 

or work practices may reasonably be 

expected to result in new or additional 

exposures at or above the action level. 

(5) Method of sample analysis. (i) The 

employer shall ensure that all samples 

taken to satisfy the monitoring 

requirements of paragraph (d) of this 

section are evaluated using the 

procedures specified in one of the 

following analytical methods: OSHA 

ID–142; NMAM 7500, NMAM 7602; 

NMAM 7603; MSHA P–2; or MSHA P– 

7. 

(ii) The employer shall ensure that 

samples are analyzed by a laboratory 

that: 

(A) Is accredited to ANS/ISO/IEC 

Standard 17025:2005 with respect to 

crystalline silica analyses by a body that 

is compliant with ISO/IEC Standard 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56488 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

17011:2004 for implementation of 

quality assessment programs; 

(B) Participates in round robin testing 

with at least two other independent 

laboratories at least every six months; 

(C) Uses the most current National 

Institute of Standards and Technology 

(NIST) or NIST traceable standards for 

instrument calibration or instrument 

calibration verification; 

(D) Implements an internal quality 

control (QC) program that evaluates 

analytical uncertainty and provides 

employers with estimates of sampling 

and analytical error; 

(E) Characterizes the sample material 

by identifying polymorphs of respirable 

crystalline silica present, identifies the 

presence of any interfering compounds 

that might affect the analysis, and makes 

any corrections necessary in order to 

obtain accurate sample analysis; 

(F) Analyzes quantitatively for 

crystalline silica only after confirming 

that the sample matrix is free of 

uncorrectable analytical interferences, 

corrects for analytical interferences, and 

uses a method that meets the following 

performance specifications: 

(1) Each day that samples are 

analyzed, performs instrument 

calibration checks with standards that 

bracket the sample concentrations; 

(2) Uses five or more calibration 

standard levels to prepare calibration 

curves and ensures that standards are 

distributed through the calibration range 

in a manner that accurately reflects the 

underlying calibration curve; and 

(3) Optimizes methods and 

instruments to obtain a quantitative 

limit of detection that represents a value 

no higher than 25 percent of the PEL 

based on sample air volume. 

(6) Employee notification of 

assessment results. (i) Within 15 

working days after completing an 

exposure assessment in accordance with 

paragraph (d) of this section, the 

employer shall individually notify each 

affected employee in writing of the 

results of that assessment or post the 

results in an appropriate location 

accessible to all affected employees. 

(ii) Whenever the exposure 

assessment indicates that employee 

exposure is above the PEL, the employer 

shall describe in the written notification 

the corrective action being taken to 

reduce employee exposure to or below 

the PEL. 

(7) Observation of monitoring. (i) 

Where air monitoring is performed to 

comply with the requirements of this 

section, the employer shall provide 

affected employees or their designated 

representatives an opportunity to 

observe any monitoring of employee 

exposure to respirable crystalline silica. 

(ii) When observation of monitoring 

requires entry into an area where the 

use of protective clothing or equipment 

is required, the employer shall provide 

the observer with protective clothing 

and equipment at no cost and shall 

ensure that the observer uses such 

clothing and equipment. 

(e) Regulated areas and access 

control. (1) General. Wherever an 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica is, or can reasonably be expected 

to be, in excess of the PEL, each 

employer shall establish and implement 

either a regulated area in accordance 

with paragraph (e)(2) of this section or 

an access control plan in accordance 

with paragraph (e)(3) of this section. 

(2) Regulated areas option. (i) 

Establishment. The employer shall 

establish a regulated area wherever an 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica is, or can reasonably be expected 

to be, in excess of the PEL. 

(ii) Demarcation. The employer shall 

demarcate regulated areas from the rest 

of the workplace in any manner that 

adequately establishes and alerts 

employees to the boundaries of the area 

and minimizes the number of 

employees exposed to respirable 

crystalline silica within the regulated 

area. 

(iii) Access. The employer shall limit 

access to regulated areas to: 

(A) Persons authorized by the 

employer and required by work duties 

to be present in the regulated area; 

(B) Any person entering such an area 

as a designated representative of 

employees for the purpose of exercising 

the right to observe monitoring 

procedures under paragraph (d) of this 

section; and 

(C) Any person authorized by the 

Occupational Safety and Health Act or 

regulations issued under it to be in a 

regulated area. 

(iv) Provision of respirators. The 

employer shall provide each employee 

and the employee’s designated 

representative entering a regulated area 

with an appropriate respirator in 

accordance with paragraph (g) of this 

section and shall require each employee 

and the employee’s designated 

representative to use the respirator 

while in a regulated area. 

(v) Protective work clothing in 

regulated areas. (A) Where there is the 

potential for employees’ work clothing 

to become grossly contaminated with 

finely divided material containing 

crystalline silica, the employer shall 

provide either of the following: 

(1) Appropriate protective clothing 

such as coveralls or similar full-bodied 

clothing; or 

(2) Any other means to remove 

excessive silica dust from contaminated 

clothing that minimizes employee 

exposure to respirable crystalline silica. 

(B) The employer shall ensure that 

such clothing is removed or cleaned 

upon exiting the regulated area and 

before respiratory protection is 

removed. 

(3) Written access control plan option. 

(i) The employer shall establish and 

implement a written access control 

plan. 

(ii) The written access control plan 

shall contain at least the following 

elements: 

(A) Provisions for a competent person 

to identify the presence and location of 

any areas where respirable crystalline 

silica exposures are, or can reasonably 

be expected to be, in excess of the PEL; 

(B) Procedures for notifying 

employees of the presence and location 

of areas identified pursuant to 

paragraph (e)(3)(ii)(A) of this section, 

and for demarcating such areas from the 

rest of the workplace where appropriate; 

(C) For multi-employer workplaces, 

the methods the employer covered by 

this section will use to inform other 

employer(s) of the presence and location 

of areas where respirable crystalline 

silica exposures may exceed the PEL, 

and any precautionary measures that 

need to be taken to protect employees; 

(D) Provisions for limiting access to 

areas where respirable crystalline silica 

exposures may exceed the PEL to 

effectively minimize the number of 

employees exposed and the level of 

employee exposure; 

(E) Procedures for providing each 

employee and their designated 

representative entering an area where 

respirable crystalline silica exposures 

may exceed the PEL with an appropriate 

respirator in accordance with paragraph 

(g) of this section, and requiring each 

employee and their designated 

representative to use the respirator 

while in the area; and 

(F) Where there is the potential for 

employees’ work clothing to become 

grossly contaminated with finely 

divided material containing crystalline 

silica: 

(1) Provisions for the employer to 

provide either appropriate protective 

clothing such as coveralls or similar 

full-bodied clothing, or any other means 

to remove excessive silica dust from 

contaminated clothing that minimizes 

employee exposure to respirable 

crystalline silica; and 

(2) Provisions for the removal or 

cleaning of such clothing. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56489 

(iii) The employer shall review and 

evaluate the effectiveness of the written 

access control plan at least annually and 

update it as necessary. 

(iv) The employer shall make the 

written access control plan available for 

examination and copying, upon request, 

to employees, their designated 

representatives, the Assistant Secretary 

and the Director. 

(f) Methods of compliance. (1) 

Engineering and work practice controls. 

The employer shall use engineering and 

work practice controls to reduce and 

maintain employee exposure to 

respirable crystalline silica to or below 

the PEL unless the employer can 

demonstrate that such controls are not 

feasible. Wherever such feasible 

engineering and work practice controls 

are not sufficient to reduce employee 

exposure to or below the PEL, the 

employer shall nonetheless use them to 

reduce employee exposure to the lowest 

feasible level and shall supplement 

them with the use of respiratory 

protection that complies with the 

requirements of paragraph (g) of this 

section. 

(2) Abrasive blasting. In addition to 

the requirements of paragraph (f)(1) of 

this section, the employer shall comply 

with the requirements of 29 CFR 

1910.94 (Ventilation), 29 CFR 1915.34 

(Mechanical paint removers), and 29 

CFR part 1915, subpart I (Personal 

Protective Equipment), as applicable, 

where abrasive blasting operations are 

conducted using crystalline silicacontaining blasting agents, or where 

abrasive blasting operations are 

conducted on substrates that contain 

crystalline silica. 

(3) Cleaning methods. (i) The 

employer shall ensure that 

accumulations of crystalline silica are 

cleaned by HEPA-filter vacuuming or 

wet methods where such accumulations 

could, if disturbed, contribute to 

employee exposure to respirable 

crystalline silica that exceeds the PEL. 

(ii) Compressed air, dry sweeping, 

and dry brushing shall not be used to 

clean clothing or surfaces contaminated 

with crystalline silica where such 

activities could contribute to employee 

exposure to respirable crystalline silica 

that exceeds the PEL. 

(4) Prohibition of rotation. The 

employer shall not rotate employees to 

different jobs to achieve compliance 

with the PEL. 

(g) Respiratory protection. (1) General. 

Where respiratory protection is required 

by this section, the employer must 

provide each employee an appropriate 

respirator that complies with the 

requirements of this paragraph and 29 

CFR 1910.134. Respiratory protection is 

required: 

(i) Where exposures exceed the PEL 

during periods necessary to install or 

implement feasible engineering and 

work practice controls; 

(ii) Where exposures exceed the PEL 

during work operations for which 

engineering and work practice controls 

are not feasible; 

(iii) During work operations for which 

an employer has implemented all 

feasible engineering and work practice 

controls and such controls are not 

sufficient to reduce exposures to or 

below the PEL; and 

(iv) During periods when the 

employee is in a regulated area pursuant 

to paragraph (e) of this section. 

(v) During periods when the employee 

is in an area where respirator use is 

required under an access control plan 

pursuant to paragraph (e)(3) of this 

section. 

(2) Respiratory protection program. 

Where respirator use is required by this 

section, the employer shall institute a 

respiratory protection program in 

accordance with 29 CFR 1910.134. 

(h) Medical surveillance. (1) General. 

(i) The employer shall make medical 

surveillance available at no cost to the 

employee, and at a reasonable time and 

place, for each employee who will be 

occupationally exposed to respirable 

crystalline silica above the PEL for 30 or 

more days per year. 

(ii) The employer shall ensure that all 

medical examinations and procedures 

required by this section are performed 

by a PLHCP as defined in paragraph (b) 

of this section. 

(2) Initial examination. The employer 

shall make available an initial (baseline) 

medical examination within 30 days 

after initial assignment, unless the 

employee has received a medical 

examination that meets the 

requirements of this section within the 

last three years. The examination shall 

consist of: 

(i) A medical and work history, with 

emphasis on: Past, present, and 

anticipated exposure to respirable 

crystalline silica, dust, and other agents 

affecting the respiratory system; any 

history of respiratory system 

dysfunction, including signs and 

symptoms of respiratory disease (e.g., 

shortness of breath, cough, wheezing); 

history of tuberculosis; and smoking 

status and history; 

(ii) A physical examination with 

special emphasis on the respiratory 

system; 

(iii) A chest X-ray (posterior/anterior 

view; no less than 14 x 17 inches and 

no more than 16 x 17 inches at full 

inspiration), interpreted and classified 

according to the International Labour 

Organization (ILO) International 

Classification of Radiographs of 

Pneumoconioses by a NIOSH-certified 

‘‘B’’ reader, or an equivalent diagnostic 

study; 

(iv) A pulmonary function test to 

include forced vital capacity (FVC) and 

forced expiratory volume at one second 

(FEV1) and FEV1/FVC ratio, 

administered by a spirometry technician 

with current certification from a NIOSHapproved spirometry course; 

(v) Testing for latent tuberculosis 

infection; and 

(vi) Any other tests deemed 

appropriate by the PLHCP. 

(3) Periodic examinations. The 

employer shall make available medical 

examinations that include the 

procedures described in paragraph 

(h)(2) (except paragraph (h)(2)(v)) of this 

section at least every three years, or 

more frequently if recommended by the 

PLHCP. 

(4) Information provided to the 

PLHCP. The employer shall ensure that 

the examining PLHCP has a copy of this 

standard, and shall provide the PLHCP 

with the following information: 

(i) A description of the affected 

employee’s former, current, and 

anticipated duties as they relate to the 

employee’s occupational exposure to 

respirable crystalline silica; 

(ii) The employee’s former, current, 

and anticipated levels of occupational 

exposure to respirable crystalline silica; 

(iii) A description of any personal 

protective equipment used or to be used 

by the employee, including when and 

for how long the employee has used that 

equipment; and 

(iv) Information from records of 

employment-related medical 

examinations previously provided to the 

affected employee and currently within 

the control of the employer. 

(5) PLHCP’s written medical opinion. 

(i) The employer shall obtain a written 

medical opinion from the PLHCP within 

30 days of each medical examination 

performed on each employee. The 

written opinion shall contain: 

(A) A description of the employee’s 

health condition as it relates to exposure 

to respirable crystalline silica, including 

the PLHCP’s opinion as to whether the 

employee has any detected medical 

condition(s) that would place the 

employee at increased risk of material 

impairment to health from exposure to 

respirable crystalline silica; 

(B) Any recommended limitations 

upon the employee’s exposure to 

respirable crystalline silica or upon the 

use of personal protective equipment 

such as respirators; 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56490 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

(C) A statement that the employee 

should be examined by an American 

Board Certified Specialist in Pulmonary 

Disease (‘‘pulmonary specialist’’) 

pursuant to paragraph (h)(6) of this 

section if the chest X-ray provided in 

accordance with this section is 

classified as 1/0 or higher by the ‘‘B’’ 

reader, or if referral to a pulmonary 

specialist is otherwise deemed 

appropriate by the PLHCP; and 

(D) A statement that the PLHCP has 

explained to the employee the results of 

the medical examination, including 

findings of any medical conditions 

related to respirable crystalline silica 

exposure that require further evaluation 

or treatment, and any recommendations 

related to use of protective clothing or 

equipment. 

(ii) The employer shall ensure that the 

PLHCP does not reveal to the employer 

specific findings or diagnoses unrelated 

to occupational exposure to respirable 

crystalline silica. 

(iii) The employer shall provide a 

copy of the PLHCP’s written medical 

opinion to the examined employee 

within two weeks after receiving it. 

(6) Additional examinations. (i) If the 

PLHCP’s written medical opinion 

indicates that an employee should be 

examined by a pulmonary specialist, the 

employer shall make available a medical 

examination by a pulmonary specialist 

within 30 days after receiving the 

PLHCP’s written medical opinion. 

(ii) The employer shall ensure that the 

examining pulmonary specialist is 

provided with all of the information that 

the employer is obligated to provide to 

the PLHCP in accordance with 

paragraph (h)(4) of this section. 

(iii) The employer shall obtain a 

written medical opinion from the 

pulmonary specialist that meets the 

requirements of paragraph (h)(5) (except 

paragraph (h)(5)(i)(C)) of this section. 

(i) Communication of respirable 

crystalline silica hazards to employees. 

(1) Hazard communication. The 

employer shall include respirable 

crystalline silica in the program 

established to comply with the Hazard 

Communication Standard (HCS) (29 

CFR 1910.1200). The employer shall 

ensure that each employee has access to 

labels on containers of crystalline silica 

and safety data sheets, and is trained in 

accordance with the provisions of HCS 

and paragraph (i)(2) of this section. The 

employer shall ensure that at least the 

following hazards are addressed: 

Cancer, lung effects, immune system 

effects, and kidney effects. 

(2) Employee information and 

training. (i) The employer shall ensure 

that each affected employee can 

demonstrate knowledge of at least the 

following: 

(A) Specific operations in the 

workplace that could result in exposure 

to respirable crystalline silica, 

especially operations where exposure 

may exceed the PEL; 

(B) Specific procedures the employer 

has implemented to protect employees 

from exposure to respirable crystalline 

silica, including appropriate work 

practices and use of personal protective 

equipment such as respirators and 

protective clothing; 

(C) The contents of this section; and 

(D) The purpose and a description of 

the medical surveillance program 

required by paragraph (h) of this 

section. 

(ii) The employer shall make a copy 

of this section readily available without 

cost to each affected employee. 

(j) Recordkeeping. (1) Air monitoring 

data. (i) The employer shall maintain an 

accurate record of all exposure 

measurement results used or relied on 

to characterize employee exposure to 

respirable crystalline silica, as 

prescribed in paragraph (d) of this 

section. 

(ii) This record shall include at least 

the following information: 

(A) The date of measurement for each 

sample taken; 

(B) The operation monitored; 

(C) Sampling and analytical methods 

used; 

(D) Number, duration, and results of 

samples taken; 

(E) Identity of the laboratory that 

performed the analysis; 

(F) Type of personal protective 

equipment, such as respirators, worn by 

the employees monitored; and 

(G) Name, social security number, and 

job classification of all employees 

represented by the monitoring, 

indicating which employees were 

actually monitored. 

(iii) The employer shall ensure that 

exposure records are maintained and 

made available in accordance with 29 

CFR 1910.1020. 

(2) Objective data. (i) The employer 

shall maintain an accurate record of all 

objective data relied upon to comply 

with the requirements of this section. 

(ii) This record shall include at least 

the following information: 

(A) The crystalline silica-containing 

material in question; 

(B) The source of the objective data; 

(C) The testing protocol and results of 

testing; 

(D) A description of the process, 

operation, or activity and how the data 

support the assessment; and 

(E) Other data relevant to the process, 

operation, activity, material, or 

employee exposures. 

(iii) The employer shall ensure that 

objective data are maintained and made 

available in accordance with 29 CFR 

1910.1020. 

(3) Medical surveillance. (i) The 

employer shall establish and maintain 

an accurate record for each employee 

covered by medical surveillance under 

paragraph (h) of this section. 

(ii) The record shall include the 

following information about the 

employee: 

(A) Name and social security number; 

(B) A copy of the PLHCP’s and 

pulmonary specialist’s written opinions; 

and 

(C) A copy of the information 

provided to the PLHCPs and pulmonary 

specialists as required by paragraph 

(h)(4) of this section. 

(iii) The employer shall ensure that 

medical records are maintained and 

made available in accordance with 29 

CFR 1910.1020. 

(k) Dates. (1) Effective date. This 

section shall become effective 

November 12, 2013 

(2) Start-up dates. (i) All obligations 

of this section, except engineering 

controls required by paragraph (f) of this 

section and laboratory requirements in 

paragraph (d)(5)(ii) of this section, 

commence 180 days after the effective 

date. 

(ii) Engineering controls required by 

paragraph (f) of this section shall be 

implemented no later than one year 

after the effective date. 

(iii) Laboratory requirements in 

paragraph (d)(5)(ii) of this section 

commence two years after the effective 

date. 

Appendix A to § 1910.1053—Medical 

Surveillance Guidelines (NonMandatory) 

Introduction 

The purpose of this non-mandatory 

Appendix is to provide helpful information 

about complying with the medical 

surveillance provisions of the Respirable 

Crystalline Silica standard, as well as to 

provide other helpful recommendations and 

information. Medical screening and 

surveillance allow for early identification of 

exposure-related health effects in individual 

workers and groups of workers, respectively, 

so that actions can be taken to both avoid 

further exposure and prevent adverse health 

outcomes. Silica-related diseases can be fatal, 

encompass a variety of target organs, and 

may have public health consequences. Thus, 

medical surveillance of silica-exposed 

workers requires involvement of clinicians 

with thorough knowledge of silica-related 

health effects and a public health 

perspective. 

This Appendix is divided into four 

sections. Section I reviews silica-related 

diseases, appropriate medical responses, and 

public health responses. Section II outlines 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56491 

the components of the medical surveillance 

program for workers exposed to silica. 

Section III describes the roles and 

responsibilities of the clinician implementing 

the program and of other medical specialists 

and public health providers. Section IV 

provides additional resources. 

I. Recognition of Silica-Related Diseases 

Overview. Silica refers specifically to the 

compound silicon dioxide (SiO2). Silica is a 

major component of sand, rock, and mineral 

ores. Exposure to fine (respirable size) 

particles of crystalline forms of silica is 

associated with a number of adverse health 

effects. Exposure to respirable crystalline 

silica can occur in foundries, industries that 

have abrasive blasting operations, paint 

manufacturing, glass and concrete product 

manufacturing, brick making, china and 

pottery manufacturing, manufacturing of 

plumbing fixtures, and many construction 

activities including highway repair, masonry, 

concrete work, rock drilling, and 

tuckpointing. 

Silicosis is an irreversible, often disabling, 

and sometimes fatal fibrotic lung disease. 

Progression of silicosis can occur despite 

removal from further exposure. Diagnosis of 

silicosis requires a history of exposure to 

silica and radiologic findings characteristic of 

silica exposure. Three different presentations 

of silicosis (chronic, accelerated, and acute) 

have been defined. 

A. Chronic Silicosis. Chronic silicosis is 

the most common presentation of silicosis 

and usually occurs after at least 10 years of 

exposure to respirable crystalline silica. The 

clinical presentation of chronic silicosis is as 

follows: 

1. Symptoms—shortness of breath and 

cough, although workers may not notice any 

symptoms early in the disease. Constitutional 

symptoms, such as fever, loss of appetite and 

fatigue, may indicate other diseases 

associated with silica exposure, such as 

mycobacterium tuberculosis infection (TB) or 

lung cancer. Workers with these symptoms 

should immediately receive further 

evaluation and treatment. 

2. Physical Examination—may be normal 

or disclose dry rales or rhonchi on lung 

auscultation. 

3. Spirometry—may be normal or may 

show only mild restriction or obstruction. 

4. Chest X-ray—classic findings are small, 

rounded opacities in the upper lung fields 

bilaterally. However, small irregular opacities 

and opacities in other lung areas can also 

occur. Rarely, ‘‘eggshell calcifications’’ are 

seen. 

5. Clinical Course—chronic silicosis in 

most cases is a slowly progressive disease. 

Accelerated and acute silicosis are much 

less common than chronic silicosis. 

However, it is critical to recognize all cases 

of accelerated and acute silicosis because 

these are life-threatening illnesses and 

because they are caused by substantial 

overexposures to respirable crystalline silica. 

Additionally, a case of acute or accelerated 

silicosis indicates a significant breakdown in 

prevention. Urgent communication with the 

employer is warranted to review exposure 

levels and protect other workers. 

B. Accelerated Silicosis. Accelerated 

silicosis occurs within 2–10 years of 

exposure and results from high levels of 

exposure to respirable crystalline silica. The 

clinical presentation of accelerated silicosis 

is as follows: 

1. Symptoms—shortness of breath, cough, 

and sometimes sputum production. Workers 

with accelerated silicosis are at high risk of 

tuberculosis, atypical mycobacterial 

infections, and fungal superinfections. 

Constitutional symptoms, such as fever, 

weight loss, hemoptysis, and fatigue, may 

herald one of these infections or the onset of 

lung cancer. 

2. Physical Examination—rales, rhonchi, or 

other abnormal lung findings in relation to 

illnesses present. Clubbing of the digits, signs 

of heart failure, and cor pulmonale may be 

present in severe disease. 

3. Spirometry—restriction or mixed 

restriction/obstruction. 

4. Chest X-ray—small rounded and/or 

irregular opacities bilaterally. Large opacities 

and lung abscesses may indicate infections, 

lung cancer, or progression to complicated 

silicosis, also termed progressive massive 

fibrosis. 

5. Clinical Course—accelerated silicosis 

has a rapid, severe course. Referral to a 

physician who is American Board of Medical 

Specialties (ABMS)-Certified in Pulmonary 

Medicine should be made whenever the 

diagnosis of accelerated silicosis is being 

considered. Referral to the appropriate 

specialist should be made if signs or 

symptoms of tuberculosis, other silica-related 

infections, or lung cancer are observed. As 

noted above, the clinician should also alert 

the employer of the need for immediate 

review of exposure controls in the worksite 

in order to protect other workers. 

C. Acute Silicosis. Acute silicosis is a rare 

disease caused by inhalation of very high 

levels of respirable crystalline silica particles. 

The pathology is similar to alveolar 

proteinosis with lipoproteinaceous material 

accumulating in the alveoli. Acute silicosis 

develops rapidly, within a few months to less 

than 2 years of exposure, and is almost 

always fatal. The clinical presentation of 

acute silicosis is as follows: 

1. Symptoms—sudden, progressive, and 

severe shortness of breath. Constitutional 

symptoms are frequently present and include 

weight loss, fatigue, productive cough, 

hemoptysis, and pleuritic chest pain. 

2. Physical Examination—dyspnea at rest, 

cyanosis, decreased breath sounds, 

inspiratory rales, clubbing of the digits, and 

fever. 

3. Spirometry—restriction or mixed 

restriction/obstruction. 

4. Chest X-ray—diffuse haziness of the 

lungs bilaterally early in the disease. As the 

disease progresses, the ‘‘ground glass’’ 

appearance of interstitial fibrosis will appear. 

5. Clinical Course—workers with acute 

silicosis are at high risk of tuberculosis, 

atypical mycobaterial infections, and fungal 

superinfections. Because this disease is 

immediately life-threatening and indicates a 

profoundly high level of exposure, it 

constitutes an immediate medical and public 

health emergency. The worker must be 

urgently referred to a physician ABMScertified in Pulmonary Medicine. As noted 

above, the clinician should also alert the 

employer of the need for immediate exposure 

controls in the worksite in order to protect 

other workers. 

During medical surveillance examinations, 

clinicians should be alert for other silicarelated health outcomes as described below. 

D. Chronic Obstructive Pulmonary Disease 

(COPD). COPD, including chronic bronchitis 

and emphysema, has also been documented 

in silica-exposed workers, including those 

who do not develop silicosis. Periodic 

spirometry tests are performed to evaluate 

each worker for progressive changes 

consistent with the development of COPD. 

Additionally, collective spirometry data for 

groups of workers should be evaluated for 

declines in lung function, thereby providing 

a mechanism to detect insufficient silica 

control measures for groups of workers. 

E. Renal and Immune System. Silica 

exposure has been associated with several 

types of kidney disease, including 

glomerulonephritis, nephrotic syndrome, and 

end stage renal disease requiring dialysis. 

Silica exposure has also been associated with 

other autoimmune conditions, including 

progressive systemic sclerosis, systemic 

lupus erythematosus, and rheumatoid 

arthritis. Early studies noted an association 

between workers with silicosis and serologic 

markers for autoimmune diseases, including 

antinuclear antibodies, rheumatoid factor, 

and immune complexes (Jalloul and Banks, 

2007). 

F. Tuberculosis (TB). Silica-exposed 

workers with latent TB are 3–30 times more 

likely to develop active pulmonary TB 

infection (ATS, 1997; Rees, 2007). Although 

silica exposure does not cause TB infection, 

individuals with latent TB infection are at 

increased risk for activation of disease if they 

have higher levels of silica exposure, greater 

profusion of radiographic abnormalities, or a 

diagnosis of silicosis. Demographic 

characteristics are known to be associated 

with increased rates of latent TB infection. 

The clinician should review the latest CDC 

information on TB incidence rates and high 

risk populations. Additionally, silicaexposed workers are at increased risk for 

contracting atypical mycobacterial infections, 

including Mycobacterium aviumintracellulare and Mycobacterium kansaii. 

G. Lung Cancer. The International Agency 

for Research on Cancer (IARC, 1997) 

classified silica as Group I (carcinogenic to 

humans). Additionally, several studies have 

indicated that the combined effect of 

exposure to respirable crystalline silica and 

smoking was greater than additive (Brown, 

2009). 

II. Medical Surveillance 

Clinicians who manage silica medical 

surveillance programs should have a 

thorough understanding of the many silicarelated diseases and health effects outlined in 

Section I of this Appendix. At each clinical 

encounter, the clinician should consider 

silica-related health outcomes, with 

particular vigilance for acute and accelerated 

silicosis. The following guidance includes 

components of the medical surveillance 

examination that are required under the 

Respirable Crystalline Silica standard, noted 

below in italics. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56492 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

A. History. A complete work and medical 

history must be performed on the initial 

examination and every three years thereafter. 

Some of the information for this history must 

also be provided by the employer to the 

clinician. A detailed history is particularly 

important in the initial evaluation. Include 

the following components in this history: 

1. Previous and Current Employment 

a. Past, current, and anticipated exposures 

to respirable crystalline silica or other 

toxic substances 

b. Exposure to dust and other agents 

affecting the respiratory system 

c. Past, current, and anticipated work 

duties relating to exposures to respirable 

crystalline silica 

d. Personal protective equipment used, 

including respirators 

e. Previous medical surveillance 

2. Medical History 

a. All past and current medical conditions 

b. Review of symptoms, with particular 

attention to respiratory symptoms 

c. History of TB infection and/or positive 

test for latent TB 

d. History of other respiratory system 

dysfunction such as obstructive 

pulmonary disease or lung cancer 

e. History of kidney disease, connective 

tissue disease, and other immune 

disease/suppression 

f. Medications and allergies 

g. Smoking status and history 

f. Previous surgeries and hospitalizations 

B. Physical Examination. A physical 

examination must be performed on the initial 

examination and every three years thereafter. 

The physical examination must emphasize 

the respiratory system and should include an 

examination of the cardiac system and an 

extremity examination for clubbing, cyanosis, 

or edema. 

C. Tuberculosis (TB) Testing. Baseline 

testing for latent or active tuberculosis must 

be done on initial examination. Current CDC 

guidelines (www.cdc.gov) should be followed 

for the application and interpretation of 

Tuberculin skin tests (TST). The 

interpretation and documentation of TST 

reactions should be performed within 48 to 

72 hours of administration by trained 

clinicians. Individuals with a positive TST 

result and those with uncertain test results 

should be referred to a local public health 

specialist. Clinicians may use alternative TB 

tests, such as interferon-g release assays 

(IGRAs), if sensitivity and specificity are 

comparable to TST (Mazurek et al, 2010). 

Current CDC guidelines for acceptable tests 

for latent TB infection should be reviewed. 

Clinicians may perform periodic (e.g., 

annual) TB testing as appropriate, based on 

individual risk factors. The diagnosis of 

silicosis or exposure to silica for 25 years or 

more are indications for annual TB testing 

(ATS, 1997). Current CDC guidance on risk 

factors for TB should be reviewed 

periodically (www.cdc.gov). Workers who 

develop active pulmonary TB should be 

referred to the local public health 

department. Workers who have evidence of 

latent TB infection may be referred to the 

local public health department for evaluation 

and treatment. 

D. Spirometry. Spirometry must be 

performed on the initial examination and 

every three years thereafter. Spirometry 

provides information about individual 

respiratory status, tracks an individual’s 

respiratory status over time, and is a valuable 

surveillance tool to track individual and 

group respiratory function. However, 

attention should be paid to quality control 

(ACOEM 2011; ATS/ERS Task Force 2005). 

Abnormal spirometry results warrant further 

clinical evaluation and possible work 

restrictions and/or treatment. 

E. Radiography. A chest roentgenogram, or 

an equivalent diagnostic study, must be 

performed on the initial examination and 

every three years thereafter. Chest 

radiography is necessary to diagnose 

silicosis, monitor the progression of silicosis, 

and identify associated conditions such as 

TB. An International Labor Organization 

(ILO) reading must be performed by a 

NIOSH-certified ‘‘B’’ reader. If the B reading 

indicates small opacities in a profusion of 

1/0 or higher, the worker must be referred to 

a physician who is certified by ABMS in 

pulmonary medicine. Medical imaging is 

currently in the process of transitioning from 

conventional film-based radiography to 

digital radiography systems. Until the ILO 

endorses the use of digital standards, 

conventional chest radiographs are needed 

for classification using the ILO system. 

Current ILO guidance on radiography for 

pneumoconioses and B-reading should be 

reviewed periodically on the ILO 

(www.ilo.org) or NIOSH (www.cdc.gov/

NIOSH) Web sites. 

F. Other Testing. It may be appropriate to 

include additional testing in a medical 

surveillance program such as baseline renal 

function tests (e.g., serum creatinine and 

urinalysis) and annual TST testing for silicaexposed workers. 

III. Roles and Responsibilities 

A. The Physician or other Licensed Health 

Care Professional (PLHCP). The PLHCP 

designation refers to an individual whose 

legally permitted scope of practice (i.e., 

license, registration, or certification) allows 

him or her to independently provide or be 

delegated the responsibility to provide some 

or all of the particular health care services 

required by the Respirable Crystalline Silica 

standard. The legally permitted scope of 

practice is determined by each State. Those 

licensed for independent practice may 

include physicians, nurse practitioners, or 

physician assistants, depending on the State. 

A medical surveillance program for workers 

exposed to silica should be directed by a 

health care professional licensed for 

independent practice. Health care 

professionals who provide clinical services 

for a silica medical surveillance program 

should have a thorough knowledge of the 

many silica-related diseases and health 

effects. Primary care practitioners who 

suspect a diagnosis of silicosis, advanced 

COPD, or other respiratory conditions 

causing impairment should promptly refer 

the affected individuals to a physician who 

is certified by ABMS in pulmonary medicine. 

1. The PLHCP is responsible for providing 

the employer with a written medical opinion 

within 30 days of an employee medical 

examination. The written opinion must 

include the following information: 

a. A description of the employee’s health 

condition as it relates to exposure to 

respirable crystalline silica, including the 

PLHCP’s opinion as to whether the employee 

has any detected medical condition(s) that 

would place the employee at increased risk 

of material impairment to health from further 

exposure to respirable crystalline silica. The 

employer should be notified if a health 

condition likely to have been caused by 

recent occupational exposure has been 

detected. Medical diagnoses and conditions 

that are not related to silica exposure must 

not be disclosed to the employer. Latent TB 

infection is not caused by silica exposure and 

must not be disclosed to the employer. All 

cases of active pulmonary TB should be 

referred to the Public Health Department. 

b. Any recommended limitations upon the 

employee’s exposure to respirable crystalline 

silica or upon the use of personal protective 

equipment such as respirators. Again, 

medical diagnoses not directly related to 

silica exposure must not be disclosed to the 

employer. Guidelines regarding ethics and 

confidentiality are available from 

professional practice organizations such as 

the American College of Occupational and 

Environmental Medicine. 

c. A statement that the employee should be 

examined by a physician who is certified by 

ABMS in pulmonary medicine, where such a 

referral is necessary. Referral to a pulmonary 

specialist is required for a chest X-ray B 

reading indicating small opacities in a 

profusion of 1/0 or higher, or if referral to a 

pulmonary specialist is otherwise deemed 

appropriate. A referral to the Public Health 

Department should not be disclosed to the 

employer. If necessary, a public health 

professional will contact the employer to 

discuss work-related conditions and/or to 

perform additional medical evaluations. 

d. A statement that the clinician has 

explained the results of the medical 

examination to the employee, including 

findings of any medical conditions related to 

respirable crystalline silica exposure that 

require further evaluation or treatment, and 

any recommendations related to use of 

protective clothing or equipment. 

2. State Reporting Requirements. Health 

care providers should be aware that some 

States require them to report cases of silicosis 

to the State Department of Health or to the 

State Department of the Environment. 

B. Medical Specialists. The Silica standard 

requires that all workers with chest X-ray B 

readings of 1/0 or higher be referred to an 

American Board Certified Specialist in 

Pulmonary Disease. The employer must 

obtain a written opinion from the specialist 

that includes the same required information 

as outlined above under IIIA1a, b, and d. 

Employers should receive any information 

concerning evidence of silica-related risk in 

their workplace (e.g., evidence of accelerated 

or acute silicosis tied to recent exposures), so 

that the employer can investigate and 

implement corrective measures if necessary. 

The employer must receive any information 

about an examined employee concerning 

work restrictions, including restrictions 

related to use of protective clothing or 

equipment. Employers must not receive other 

medical diagnoses or confidential health 

information. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56493 

C. Public Health Providers. Clinicians 

should refer latent and active TB cases to 

their local Public Health Department. In 

addition to diagnosis and treatment of 

individual cases, public health providers 

promptly evaluate other potentially affected 

persons, including coworkers. Because silicaexposed workers are at increased risk of 

progression from latent to active TB, 

treatment of latent infection is recommended. 

The diagnosis of TB, acute or accelerated 

silicosis, or other silica-related diseases and 

infections should serve as sentinel findings. 

In addition to the local and state health 

departments, the National Institute of 

Occupational Safety and Health (NIOSH) can 

provide assistance upon request through 

their Health Hazard Evaluation program. 

IV. Resources and References 

American College of Occupational and 

Environmental Medicine (ACOEM), 

Position Statement. Medical Surveillance 

of Workers Exposed to Crystalline Silica. 

06/27/2005. 

ACOEM, Position Statement. Spirometry in 

the Occupational Health Setting. 04/05/ 

2010. 

American Thoracic Society (ATS): Medical 

Section of the American Lung 

Association. Adverse Effects of 

Crystalline Silica Exposure. Am J Respir 

Crit Care Med. Vol. 155. pp 761–765, 

1997. 

Brown T. Silica Exposure, Smoking, Silicosis 

and Lung Cancer—Complex Interactions. 

Occupational Medicine. 2009 59(2):89– 

95. 

Center for Disease Control and Prevention 

(CDC). Guide for Primary Health Care 

Providers: Targeted Tuberculin Testing 

and Treatment of Latent Tuberculosis 

Infection. 2005. 

Centers for Disease Control and Prevention. 

Screening for Tuberculosis and 

Tuberculosis Infection in High-Risk 

Populations. Recommendations of the 

Advisory Council for Elimination of 

Tuberculosis. MMWR 1995; 44(RR– 

11):18–34. 

International Agency for Research on Cancer 

(IARC) Working Group on the Evaluation 

of Carcinogenic Risks to Humans. Silica, 

Some Silicates, Coal Dust and Paraaramid Fibrils. Lyon, France. 1997. 

Jalloul AS, Banks DE. The Health Effects of 

Silica Exposure. In: Rom WN and 

Markowitz SB (Eds). Environmental and 

Occupational Medicine, 4th edition. 

Lippincott, Williams and Wilkins, 

Philadelphia. 2007. pp.365–387. 

Mazurek GH, Jereb J, Vernon A et al. Updated 

Guidelines for Using Interferon Gamma 

Release Assays to Detect Mycobacterium 

tuberculosis Infection—United States, 

2010. Morbidity and Mortality Weekly 

Report (MMWR), 6/25/10; 59(RR05):1– 

25. 

Miller MR et al. Standardisation of 

spirometry from SERIES ‘‘ATS/ERS 

TASK FORCE: STANDARDISATION OF 

LUNG FUNCTION TESTING’’ Edited by 

V. Brusasco, R. Crapo and G. Viegi. Eur 

Respir J 2005; 26:319–338. 

National Institute of Occupational Safety and 

Health (NIOSH) B reader Program. 

Access online for more information on 

interpretation of X-rays for silicosis and 

a list of certified B-readers. http://

www.cdc.gov/niosh/topics/

chestradiography/breader-info.html. 

NIOSH Hazard Review: Health Effects of 

Occupational Exposure to Respirable 

Crystalline Silica; Department of Health 

and Human Services, CDC, NIOSH, April 

2002. 

Occupational Health Program for Exposure to 

Crystalline Silica in the Industrial Sand 

Industry. National Industrial Sand 

Association, 2nd ed. 2010. 

Rees D, Murray J. Silica, silicosis and 

tuberculosis. Int J Tuberc Lung Dis 

11(5):474–484. 

Screening and Surveillance of workers 

exposed to mineral dust; Gregory R. 

Wagner, Director, Division of Respiratory 

Diseases, NIOSH, Morgantown, WV, 

U.S.A.; WHO, Geneva 1996. 

PART 1915—OCCUPATIONAL SAFETY 

AND HEALTH FOR SHIPYARD 

EMPLOYMENT 

■ 5. The authority citation for 29 CFR 

part 1915 is revised to read as follows: 

Authority: Section 41, Longshore and 

Harbor Workers’ Compensation Act (33 

U.S.C. 941); Sections 4, 6, and 8 of the 

Occupational Safety and Health Act of 1970 

(29 U.S.C. 653, 655, 657); Secretary of Labor’s 

Order No. 8–76 (41 FR 25059), 9–83 (48 FR 

35736), 1–90 (55 FR 9033), 6–96 (62 FR 111), 

3–2000 (65 FR 50017), 5–2002 (67 FR 65008), 

5–2007 (72 FR 31160), or 4–2010 (75 FR 

55355), as applicable; 29 CFR part 1911. 

Section 1915.120 and 1915.152 of 29 CFR 

also issued under 29 CFR part 1911. 

■ 6. In § 1915.1000, Table Z— 

Shipyards: 

■ a. remove ‘‘Silica, crystalline 

cristobalite, respirable dust’’, ‘‘Silica, 

crystalline quartz, respirable dust’’, 

‘‘Silica, crystalline tripoli (as quartz), 

respirable dust’’, and ‘‘Silica, crystalline 

tridymite, respirable dust’’; 

■ b. add ‘‘Silica, crystalline, respirable 

dust; see 1910.1053’’ in alphabetical 

order; and 

■ c. revise the entry ‘‘SILICA:’’ under 

‘‘Mineral Dusts’’, to read as follows: 

§ 1915.1000 Air contaminants. 

* * * * * 

TABLE Z—SHIPYARDS

Substance CAS No.d ppm a * mg/m 3 b * Skin designation 

*******

Silica, crystalline, respirable dust; See 1910.1053 .......................... ............................ ............................ ............................ ............................

* * * * * * * 

MINERAL DUSTS

Substance mppcf (j)

SILICA: 

Amorphous, including natural diatomaceous earth .................................................................................................................. 20 

* * * * * 

PART 1926—SAFETY AND HEALTH 

REGULATIONS FOR CONSTRUCTION 

■ 7. The authority citation for 29 CFR 

part 1926 is revised to read as follows: 

Authority: Section 3704 of the Contract 

Work Hours and Safety Standards Act (40 

U.S.C. 3701 et seq.); Sections 4, 6, and 8 of 

the Occupational Safety and Health Act of 

1970 (29 U.S.C. 653, 655, 657); and Secretary 

of Labor’s Order No. 8–76 (41 FR 25059), 9– 

83 (48 FR 35736), 1–90 (55 FR 9033), 6–96 

(62 FR 111), 3–2000 (65 FR 50017), 5–2002 

(67 FR 65008), 5–2007 (72 FR 31159), or 4– 

2010 (75 FR 55355), as applicable; and 29 

CFR part 1911. 

■ 8. In Appendix A to § 1926.55: 

■ a. Remove ‘‘Silica, crystalline 

cristobalite, respirable dust’’, ‘‘Silica, 

crystalline quartz, respirable dust’’, 

‘‘Silica, crystalline tripoli (as quartz), 

respirable dust’’, and ‘‘Silica, crystalline 

tridymite, respirable dust’’; 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56494 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

■ b. add ‘‘Silica, crystalline, respirable 

dust; see 1926.1053’’ in alphabetical 

order; and 

■ c. revise the entry ‘‘SILICA:’’ under 

‘‘Mineral Dusts’’, to read as follows: 

§ 1926.55 Gases, vapors, fumes, dusts, 

and mists. 

* * * * * 

Appendix A to § 1926.55—1970 

American Conference of Governmental 

Industrial Hygienists’ Threshold Limit 

Values of Airborne Contaminants 

THRESHOLD LIMIT VALUES OF AIRBORNE CONTAMINANTS FOR CONSTRUCTION

Substance CAS No.d ppm a mg/m3 b Skin designation 

*******

Silica, crystalline, respirable dust; see 1926.1053 ........................... ............................ ............................ ............................ ............................

*******

MINERAL DUSTS

Substance mppcf (j)

SILICA: 

Amorphous, including natural diatomaceous earth .................................................................................................................. 20 

* * * * * 

■ 9. Add a new § 1926.1053, to read as 

follows: 

§ 1926.1053 Respirable crystalline silica. 

(a) Scope and application. (1) This 

section applies to all occupational 

exposures to respirable crystalline silica 

in construction work as defined in 29 

CFR 1910.12(b) and covered under 29 

CFR part 1926. 

(b) Definitions. For the purposes of 

this section the following definitions 

apply: 

Action level means a concentration of 

airborne respirable crystalline silica of 

25 micrograms per cubic meter of air (25 

mg/m3), calculated as an 8-hour timeweighted average (TWA). 

Assistant Secretary means the 

Assistant Secretary of Labor for 

Occupational Safety and Health, U.S. 

Department of Labor, or designee. 

Director means the Director of the 

National Institute for Occupational 

Safety and Health (NIOSH), U.S. 

Department of Health and Human 

Services, or designee. 

Competent person means one who is 

capable of identifying existing and 

predictable respirable crystalline silica 

hazards in the surroundings or working 

conditions and who has authorization to 

take prompt corrective measures to 

eliminate them. 

Employee exposure means the 

exposure to airborne respirable 

crystalline silica that would occur if the 

employee were not using a respirator. 

High-efficiency particulate air [HEPA] 

filter means a filter that is at least 99.97 

percent efficient in removing monodispersed particles of 0.3 micrometers 

in diameter. 

Objective data means information 

such as air monitoring data from 

industry-wide surveys or calculations 

based on the composition or chemical 

and physical properties of a substance 

demonstrating employee exposure to 

respirable crystalline silica associated 

with a particular product or material or 

a specific process, operation, or activity. 

The data must reflect workplace 

conditions closely resembling the 

processes, types of material, control 

methods, work practices, and 

environmental conditions in the 

employer’s current operations. 

Physician or other licensed health 

care professional [PLHCP] means an 

individual whose legally permitted 

scope of practice (i.e., license, 

registration, or certification) allows him 

or her to independently provide or be 

delegated the responsibility to provide 

some or all of the particular health care 

services required by paragraph (h) of 

this section. 

Regulated area means an area, 

demarcated by the employer, where an 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica exceeds, or can reasonably be 

expected to exceed, the PEL. 

Respirable crystalline silica means 

airborne particles that contain quartz, 

cristobalite, and/or tridymite and whose 

measurement is determined by a 

sampling device designed to meet the 

characteristics for respirable-particlesize-selective samplers specified in the 

International Organization for 

Standardization (ISO) 7708:1995: Air 

Quality—Particle Size Fraction 

Definitions for Health-Related 

Sampling. 

This section means this respirable 

crystalline silica standard, 29 CFR 

1926.1053. 

(c) Permissible exposure limit (PEL). 

The employer shall ensure that no 

employee is exposed to an airborne 

concentration of respirable crystalline 

silica in excess of 50 mg/m3, calculated 

as an 8-hour TWA. 

(d) Exposure assessment. (1) General. 

(i) Except as provided for in paragraph 

(d)(8) of this section, each employer 

covered by this section shall assess the 

exposure of employees who are or may 

reasonably be expected to be exposed to 

respirable crystalline silica at or above 

the action level. 

(ii) The employer shall determine 

employee exposures from breathing 

zone air samples that reflect the 8-hour 

TWA exposure of each employee. 

(iii) The employer shall determine 8- 

hour TWA exposures on the basis of one 

or more air samples that reflect the 

exposures of employees on each shift, 

for each job classification, in each work 

area. Where several employees perform 

the same job tasks on the same shift and 

in the same work area, the employer 

may sample a representative fraction of 

these employees in order to meet this 

requirement. In representative sampling, 

the employer shall sample the 

employee(s) who are expected to have 

the highest exposure to respirable 

crystalline silica. 

(2) Initial exposure assessment. (i) 

Except as provided for in paragraph 

(d)(2)(ii) of this section, each employer 

shall perform initial monitoring of 

employees who are, or may reasonably 

be expected to be, exposed to airborne 

concentrations of respirable crystalline 

silica at or above the action level. 

(ii) The employer may rely on existing 

data to satisfy this initial monitoring 

requirement where the employer: 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56495 

(A) Has monitored employee 

exposures after [INSERT DATE 12 

MONTHS PRIOR TO EFFECTIVE DATE 

OF FINAL RULE] under conditions that 

closely resemble those currently 

prevailing, provided that such 

monitoring satisfies the requirements of 

paragraph (d)(5)(i) of this section with 

respect to analytical methods employed; 

or 

(B) Has objective data that 

demonstrate that respirable crystalline 

silica is not capable of being released in 

airborne concentrations at or above the 

action level under any expected 

conditions of processing, use, or 

handling. 

(3) Periodic exposure assessments. If 

initial monitoring indicates that 

employee exposures are below the 

action level, the employer may 

discontinue monitoring for those 

employees whose exposures are 

represented by such monitoring. If 

initial monitoring indicates that 

employee exposures are at or above the 

action level, the employer shall repeat 

air monitoring to assess employee 

exposures to respirable crystalline silica 

either under the fixed schedule 

prescribed in paragraph (d)(3)(i) of this 

section or in accordance with the 

performance-based requirement 

prescribed in paragraph (d)(3)(ii) of this 

section. 

(i) Fixed schedule option. (A) Where 

initial or subsequent exposure 

monitoring reveals that employee 

exposures are at or above the action 

level but at or below the PEL, the 

employer shall repeat such monitoring 

at least every six months. 

(B) Where initial or subsequent 

exposure monitoring reveals that 

employee exposures are above the PEL, 

the employer shall repeat such 

monitoring at least every three months. 

(C) The employer shall continue 

monitoring at the required frequency 

until at least two consecutive 

measurements, taken at least 7 days 

apart, are below the action level, at 

which time the employer may 

discontinue monitoring for that 

employee, except as otherwise provided 

in paragraph (d)(4) of this section. 

(ii) Performance option. The employer 

shall assess the 8-hour TWA exposure 

for each employee on the basis of any 

combination of air monitoring data or 

objective data sufficient to accurately 

characterize employee exposures to 

respirable crystalline silica. 

(4) Additional exposure assessments. 

The employer shall conduct additional 

exposure assessments as required under 

paragraph (d)(3) of this section 

whenever a change in the production, 

process, control equipment, personnel, 

or work practices may reasonably be 

expected to result in new or additional 

exposures at or above the action level. 

(5) Method of sample analysis. (i) The 

employer shall ensure that all samples 

taken to satisfy the monitoring 

requirements of paragraph (d) of this 

section are evaluated using the 

procedures specified in one of the 

following analytical methods: OSHA 

ID–142; NMAM 7500, NMAM 7602; 

NMAM 7603; MSHA P–2; or MSHA 

P–7. 

(ii) The employer shall ensure that 

samples are analyzed by a laboratory 

that: 

(A) Is accredited to ANS/ISO/IEC 

Standard 17025:2005 with respect to 

crystalline silica analyses by a body that 

is compliant with ISO/IEC Standard 

17011:2004 for implementation of 

quality assessment programs; 

(B) Participates in round robin testing 

with at least two other independent 

laboratories at least every six months; 

(C) Uses the most current National 

Institute of Standards and Technology 

(NIST) or NIST traceable standards for 

instrument calibration or instrument 

calibration verification; 

(D) Implements an internal quality 

control (QC) program that evaluates 

analytical uncertainty and provides 

employers with estimates of sampling 

and analytical error; 

(E) Characterizes the sample material 

by identifying polymorphs of respirable 

crystalline silica present, identifies the 

presence of any interfering compounds 

that might affect the analysis, and makes 

any corrections necessary in order to 

obtain accurate sample analysis; 

(F) Analyzes quantitatively for 

crystalline silica only after confirming 

that the sample matrix is free of 

uncorrectable analytical interferences, 

corrects for analytical interferences, and 

uses a method that meets the following 

performance specifications: 

(1) Each day that samples are 

analyzed, performs instrument 

calibration checks with standards that 

bracket the sample concentrations; 

(2) Uses five or more calibration 

standard levels to prepare calibration 

curves and ensures that standards are 

distributed through the calibration range 

in a manner that accurately reflects the 

underlying calibration curve; and 

(3) Optimizes methods and 

instruments to obtain a quantitative 

limit of detection that represents a value 

no higher than 25 percent of the PEL 

based on sample air volume. 

(6) Employee notification of 

assessment results. (i) Within five 

working days after completing an 

exposure assessment in accordance with 

paragraph (d) of this section, the 

employer shall individually notify each 

affected employee in writing of the 

results of that assessment or post the 

results in an appropriate location 

accessible to all affected employees. 

(ii) Whenever the exposure 

assessment indicates that employee 

exposure is above the PEL, the employer 

shall describe in the written notification 

the corrective action being taken to 

reduce employee exposure to or below 

the PEL. 

(7) Observation of monitoring. (i) 

Where air monitoring is performed to 

comply with the requirements of this 

section, the employer shall provide 

affected employees or their designated 

representatives an opportunity to 

observe any monitoring of employee 

exposure to respirable crystalline silica. 

(ii) When observation of monitoring 

requires entry into an area where the 

use of protective clothing or equipment 

is required, the employer shall provide 

the observer with protective clothing 

and equipment at no cost and shall 

ensure that the observer uses such 

clothing and equipment. 

(8) Specific operations. (i) Where 

employees perform operations listed in 

Table 1 in paragraph (f) of this section 

and the employer has fully 

implemented the engineering controls, 

work practices, and respiratory 

protection specified in Table 1 for that 

operation, the employer is not required 

to assess the exposure of employees 

performing such operations. 

(ii) For the purposes of complying 

with all other requirements of this 

section, the employer must presume 

that each employee performing an 

operation listed in Table 1 that requires 

a respirator is exposed above the PEL, 

unless the employer can demonstrate 

otherwise in accordance with the 

exposure assessment requirements of 

paragraph (d) of this section. 

(e) Regulated areas and access 

control. (1) General. Wherever an 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica is, or can reasonably be expected 

to be, in excess of the PEL, each 

employer shall establish and implement 

either a regulated area in accordance 

with paragraph (e)(2) of this section or 

an access control plan in accordance 

with paragraph (e)(3) of this section. 

(2) Regulated areas option. (i) 

Establishment. The employer shall 

establish a regulated area wherever an 

employee’s exposure to airborne 

concentrations of respirable crystalline 

silica is, or can reasonably be expected 

to be, in excess of the PEL. 

(ii) Demarcation. The employer shall 

demarcate regulated areas from the rest 

of the workplace in any manner that 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56496 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

adequately establishes and alerts 

employees to the boundaries of the area 

and minimizes the number of 

employees exposed to respirable 

crystalline silica within the regulated 

area. 

(iii) Access. The employer shall limit 

access to regulated areas to: 

(A) Persons authorized by the 

employer and required by work duties 

to be present in the regulated area; 

(B) Any person entering such an area 

as a designated representative of 

employees for the purpose of exercising 

the right to observe monitoring 

procedures under paragraph (d) of this 

section; and 

(C) Any person authorized by the 

Occupational Safety and Health Act or 

regulations issued under it to be in a 

regulated area. 

(iv) Provision of respirators. The 

employer shall provide each employee 

and the employee’s designated 

representative entering a regulated area 

with an appropriate respirator in 

accordance with paragraph (g) of this 

section and shall require each employee 

and the employee’s designated 

representative to use the respirator 

while in a regulated area. 

(v) Protective work clothing in 

regulated areas. (A) Where there is the 

potential for employees’ work clothing 

to become grossly contaminated with 

finely divided material containing 

crystalline silica, the employer shall 

provide either of the following: 

(1) Appropriate protective clothing 

such as coveralls or similar full-bodied 

clothing; or 

(2) Any other means to remove 

excessive silica dust from contaminated 

clothing that minimizes employee 

exposure to respirable crystalline silica. 

(B) The employer shall ensure that 

such clothing is removed or cleaned 

upon exiting the regulated area and 

before respiratory protection is 

removed. 

(3) Written access control plan option. 

(i) The employer shall establish and 

implement a written access control 

plan. 

(ii) The written access control plan 

shall contain at least the following 

elements: 

(A) Provisions for a competent person 

to identify the presence and location of 

any areas where respirable crystalline 

silica exposures are, or can reasonably 

be expected to be, in excess of the PEL; 

(B) Procedures for notifying 

employees of the presence and location 

of areas identified pursuant to 

paragraph (e)(3)(ii)(A) of this section, 

and for demarcating such areas from the 

rest of the workplace where appropriate; 

(C) For multi-employer workplaces, 

the methods the employer covered by 

this section will use to inform other 

employer(s) of the presence and location 

of areas where respirable crystalline 

silica exposures may exceed the PEL, 

and any precautionary measures that 

need to be taken to protect employees; 

(D) Provisions for limiting access to 

areas where respirable crystalline silica 

exposures may exceed the PEL to 

effectively minimize the number of 

employees exposed and the level of 

employee exposure; 

(E) Procedures for providing each 

employee and their designated 

representative entering an area where 

respirable crystalline silica exposures 

may exceed the PEL with an appropriate 

respirator in accordance with paragraph 

(g) of this section, and requiring each 

employee and their designated 

representative to use the respirator 

while in the area; and 

(F) Where there is the potential for 

employees’ work clothing to become 

grossly contaminated with finely 

divided material containing crystalline 

silica: 

(1) Provisions for the employer to 

provide either appropriate protective 

clothing such as coveralls or similar 

full-bodied clothing, or any other means 

to remove excessive silica dust from 

contaminated clothing that minimizes 

employee exposure to respirable 

crystalline silica; and 

(2) Provisions for the removal or 

cleaning of such clothing. 

(iii) The employer shall review and 

evaluate the effectiveness of the written 

access control plan at least annually and 

update it as necessary. 

(iv) The employer shall make the 

written access control plan available for 

examination and copying, upon request, 

to employees, their designated 

representatives, the Assistant Secretary 

and the Director. 

(f) Methods of compliance. (1) 

Engineering and work practice controls. 

The employer shall use engineering and 

work practice controls to reduce and 

maintain employee exposure to 

respirable crystalline silica to or below 

the PEL unless the employer can 

demonstrate that such controls are not 

feasible. Wherever such feasible 

engineering and work practice controls 

are not sufficient to reduce employee 

exposure to or below the PEL, the 

employer shall nonetheless use them to 

reduce employee exposure to the lowest 

feasible level and shall supplement 

them with the use of respiratory 

protection that complies with the 

requirements of paragraph (g) of this 

section. 

(2) Specific operations. For the 

operations listed in Table 1, if the 

employer fully implements the 

engineering controls, work practices, 

and respiratory protection described in 

Table 1, the employer shall be 

considered to be in compliance with 

paragraph (f)(1) of this section. (NOTE: 

The employer must comply with all 

other obligations of this section, 

including the PEL specified in 

paragraph (c) of this section.) 

TABLE 1—EXPOSURE CONTROL METHODS FOR SELECTED CONSTRUCTION OPERATIONS

Operation Engineering and work practice control methods 

Required air-purifying respirator 

(minimum assigned protection factor) 

≤ 4 hr/day > 4 hr/day 

Using Stationary Masonry 

Saws.

Use saw equipped with integrated water delivery system.

Note: Additional specifications: 

None .................................. Half-Mask (10). 

• Change water frequently to avoid silt build-up in 

water. 

• Prevent wet slurry from accumulating and drying. 

• Operate equipment such that no visible dust is emitted from the process. 

• When working indoors, provide sufficient ventilation 

to prevent build-up of visible airborne dust. 

• Ensure saw blade is not excessively worn. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56497 

TABLE 1—EXPOSURE CONTROL METHODS FOR SELECTED CONSTRUCTION OPERATIONS—Continued 

Operation Engineering and work practice control methods 

Required air-purifying respirator 

(minimum assigned protection factor) 

≤ 4 hr/day > 4 hr/day 

Using Hand-Operated Grinders.Use water-fed grinder that continuously feeds water to 

the cutting surface.

OR 

None .................................. Half-Mask (10). 

Use grinder equipped with commercially available 

shroud and dust collection system, operated and 

maintained to minimize dust emissions. Collector 

must be equipped with a HEPA filter and must operate at 25 cubic feet per minute (cfm) or greater airflow per inch of blade diameter.

Half-Mask (10) ................... Half-Mask (10). 

Note: Additional specifications (wherever applicable): 

• Prevent wet slurry from accumulating and drying. 

• Operate equipment such that no visible dust is emitted from the process. 

• When working indoors, provide sufficient ventilation 

to prevent build-up of visible airborne dust. 

Tuckpointing ........................ Use grinder equipped with commercially available 

shroud and dust collection system. Grinder must be 

operated flush against the working surface and work 

must be performed against the natural rotation of 

the blade (i.e., mortar debris must be directed into 

the exhaust). Use vacuums that provide at least 80 

cfm airflow through the shroud and include filters at 

least 99 percent efficient.

Note: Additional specifications: 

• Operate equipment such that no visible dust is emitted from the process. 

Powered air-purifying respirator (PAPR) with 

loose-fitting helmet or 

negative pressure full 

facepiece (25).

Powered air-purifying respirator (PAPR) with 

loose-fitting helmet or 

negative pressure full 

facepiece (25). 

• When working in enclosed spaces, provide sufficient 

ventilation to prevent build-up of visible airborne 

dust. 

Using Jackhammers and 

Other Impact Drillers.

Apply a continuous stream or spray of water at the 

point of impact.

OR 

None .................................. Half-Mask (10). 

Use tool-mounted shroud and HEPA-filtered dust collection system.None .................................. Half-Mask (10). 

Note: Additional specifications: 

• Operate equipment such that no visible dust is emitted from the process. 

• When working indoors, provide sufficient ventilation 

to prevent build-up of visible airborne dust. 

Using Rotary Hammers or 

Drills (except overhead).

Use drill equipped with hood or cowl and HEPA-filtered dust collector. Eliminate blowing or dry sweeping drilling debris from working surface.

Note: Additional specifications: 

None .................................. None. 

• Operate equipment such that no visible dust is emitted from the process. 

• When working indoors, provide sufficient ventilation 

to prevent build-up of visible airborne dust. 

• Use dust collector in accordance with manufacturer 

specifications. 

Operating Vehicle-Mounted 

Drilling Rigs for Rock.

Use dust collection system around drill bit and provide 

a low-flow water spray to wet the dust discharged 

from the dust collector.

None .................................. None. 

Note: Additional specifications: 

• Operate equipment such that no visible dust is emitted from the process. 

• Half-mask respirator is to be used when working 

under the shroud.

• Use dust collector in accordance with manufacturer 

specifications.

For equipment operator working within an enclosed 

cab having the following characteristics: 

None .................................. None. 

• Cab is air conditioned and positive pressure is 

maintained.

• Incoming air is filtered through a prefilter and HEPA 

filter.

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56498 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

TABLE 1—EXPOSURE CONTROL METHODS FOR SELECTED CONSTRUCTION OPERATIONS—Continued 

Operation Engineering and work practice control methods 

Required air-purifying respirator 

(minimum assigned protection factor) 

≤ 4 hr/day > 4 hr/day 

• Cab is maintained as free as practicable from settled dust.

• Door seals and closing mechanisms are working 

properly.

Operating Vehicle-Mounted 

Drilling Rigs for Concrete.

Use dust collection system around drill bit and provide 

a low-flow water spray to wet the dust discharged 

from the dust collector.

Note: Additional specifications: 

• Use smooth ducts and maintain duct transport velocity at 4,000 feet per minute. 

None .................................. Half-Mask (10). 

• Provide duct clean-out points. 

• Install pressure gauges across dust collection filters. 

• Activate LEV before drilling begins and deactivate 

after drill bit stops rotating. 

• Operate equipment such that no visible dust is emitted from the process. 

• Use dust collector in accordance with manufacturer 

specifications. 

For equipment operator working within an enclosed 

cab having the following characteristics: 

• Cab is air conditioned and positive pressure is 

maintained. 

None .................................. None. 

• Incoming air is filtered through a prefilter and HEPA 

filter. 

• Cab is maintained as free as practicable from settled dust. 

• Door seals and closing mechanisms are working 

properly. 

Milling For drivable milling machines:.

Use water-fed system that delivers water continuously at the cut point to suppress dust.None .................................. Half-Mask (10). 

Note: Additional specifications: 

• Operate equipment such that no visible dust is emitted from the drum box and conveyor areas. 

For walk-behind milling tools: 

Use water-fed equipment that continuously feeds 

water to the cutting surface.

None .................................. Half-Mask (10). 

OR 

Use tool equipped with commercially available 

shroud and dust collection system. Collector 

must be equipped with a HEPA filter and must 

operate at an adequate airflow to minimize airborne visible dust.

None .................................. Half-Mask (10). 

Note: Additional specifications: 

• Use dust collector in accordance with manufacturer 

specifications including airflow rate.

Using Handheld Masonry 

Saws.

Use water-fed system that delivers water continuously 

at the cut point.

Used outdoors ........................................................ None .................................. Half-Mask (10). 

Used indoors or within partially sheltered area ..... Half-Mask (10) ................... Half-Mask (10). 

OR 

Use saw equipped with local exhaust dust collection 

system.

Used outdoors ........................................................ Half-Mask (10) ................... Half-Mask (10). 

Used indoors or within partially sheltered area ..... Full Facepiece (50) ........... Full Facepiece (50). 

Note: Additional specifications: 

• Prevent wet slurry from accumulating and drying. 

• Operate equipment such that no visible dust is emitted from the process. 

• When working indoors, provide sufficient ventilation 

to prevent build-up of visible airborne dust. 

• Use dust collector in accordance with manufacturer 

specifications. 

Using Portable Walk-Behind 

or Drivable Masonry Saws.

Use water-fed system that delivers water continuously 

at the cut point. 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56499 

TABLE 1—EXPOSURE CONTROL METHODS FOR SELECTED CONSTRUCTION OPERATIONS—Continued 

Operation Engineering and work practice control methods 

Required air-purifying respirator 

(minimum assigned protection factor) 

≤ 4 hr/day > 4 hr/day 

Used outdoors ........................................................ None .................................. None. 

Used indoors or within partially sheltered area ..... Half-Mask (10) ................... Half-Mask (10). 

Note: Additional specifications: 

• Prevent wet slurry from accumulating and drying. 

• Operate equipment such that no visible dust is emitted from the process. 

• When working indoors, provide sufficient ventilation 

to prevent build-up of visible airborne dust. 

Rock Crushing ..................... Use wet methods or dust suppressants .......................

OR 

Half-Mask (10) ................... Half-Mask (10). 

Use local exhaust ventilation systems at feed hoppers 

and along conveyor belts.

Half-Mask (10) ................... Half-Mask (10). 

Note: Additional specifications: 

• Operate equipment such that no visible dust is emitted from the process. 

For equipment operator working within an enclosed 

cab having the following characteristics: 

None .................................. None. 

• Cab is air conditioned and positive pressure is 

maintained; 

• Incoming air is filtered through a prefilter and HEPA 

filter; 

• Cab is maintained as free as practicable from settled dust; and 

• Door seals and closing mechanisms are working 

properly. 

Drywall Finishing (with silica-containing material).Use pole sander or hand sander equipped with a dust 

collection system. Use dust collector in accordance 

with manufacturer specifications.

OR 

None .................................. None. 

Use wet methods to smooth or sand the drywall seam None .................................. None. 

Use of Heavy Equipment 

During Earthmoving.

Operate equipment from within an enclosed cab having the following characteristics: 

• Cab is air conditioned and positive pressure is 

maintained; 

• Incoming air is filtered through a prefilter and HEPA 

filter; 

• Cab is maintained as free as practicable from settled dust; and 

• Door seals and closing mechanisms are working 

properly. 

None .................................. None. 

NOTE 1: For the purposes of complying with all other requirements of this section, the employer must presume that each employee performing 

an operation listed in Table 1 that requires a respirator is exposed above the PEL. 

NOTE 2: Where an employee performs more than one operation during the course of a day, and the total duration of all operations combined is 

> 4 hr/day, the required air-purifying respirator for each operation is the respirator specified for > 4 hr/day. If the total duration of all operations 

combined is ≤ 4 hr/day, the required air-purifying respirator for each operation is the respirator specified for ≤ 4 hr/day. 

(3) Abrasive blasting. In addition to 

the requirements of paragraph (f)(1) of 

this section, the employer shall comply 

with the requirements of 29 CFR 

1926.57 (Ventilation) where abrasive 

blasting operations are conducted using 

crystalline silica-containing blasting 

agents, or where abrasive blasting 

operations are conducted on substrates 

that contain crystalline silica. 

(4) Cleaning methods. (i) The 

employer shall ensure that 

accumulations of crystalline silica are 

cleaned by HEPA-filter vacuuming or 

wet methods where such accumulations 

could, if disturbed, contribute to 

employee exposure to respirable 

crystalline silica that exceeds the PEL. 

(ii) Compressed air, dry sweeping, 

and dry brushing shall not be used to 

clean clothing or surfaces contaminated 

with crystalline silica where such 

activities could contribute to employee 

exposure to respirable crystalline silica 

that exceeds the PEL. 

(5) Prohibition of rotation. The 

employer shall not rotate employees to 

different jobs to achieve compliance 

with the PEL. 

(g) Respiratory protection. (1) General. 

Where respiratory protection is required 

by this section, the employer must 

provide each employee an appropriate 

respirator that complies with the 

requirements of this paragraph and 29 

CFR 1910.134. Respiratory protection is 

required: 

(i) Where exposures exceed the PEL 

during periods necessary to install or 

implement feasible engineering and 

work practice controls; 

(ii) Where exposures exceed the PEL 

during work operations for which 

engineering and work practice controls 

are not feasible; 

(iii) During work operations for which 

an employer has implemented all 

feasible engineering and work practice 

controls and such controls are not 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56500 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

sufficient to reduce exposures to or 

below the PEL; 

(iv) During periods when the 

employee is in a regulated area; and 

(v) During periods when the employee 

is in an area where respirator use is 

required under an access control plan 

pursuant to paragraph (e)(3) of this 

section. 

(2) Respiratory protection program. 

Where respirator use is required by this 

section, the employer shall institute a 

respiratory protection program in 

accordance with 29 CFR 1910.134. 

(3) Specific operations. For the 

operations listed in Table 1 in paragraph 

(f) of this section, if the employer fully 

implements the engineering controls, 

work practices, and respiratory 

protection described in Table 1, the 

employer shall be considered to be in 

compliance with the requirements for 

selection of respirators in 29 CFR 

1910.134 paragraph (d). 

(h) Medical surveillance. (1) General. 

(i) The employer shall make medical 

surveillance available at no cost to the 

employee, and at a reasonable time and 

place, for each employee who will be 

occupationally exposed to respirable 

crystalline silica above the PEL for 30 or 

more days per year. 

(ii) The employer shall ensure that all 

medical examinations and procedures 

required by this section are performed 

by a PLHCP as defined in paragraph (b) 

of this section. 

(2) Initial examination. The employer 

shall make available an initial (baseline) 

medical examination within 30 days 

after initial assignment, unless the 

employee has received a medical 

examination that meets the 

requirements of this section within the 

last three years. The examination shall 

consist of: 

(i) A medical and work history, with 

emphasis on: past, present, and 

anticipated exposure to respirable 

crystalline silica, dust, and other agents 

affecting the respiratory system; any 

history of respiratory system 

dysfunction, including signs and 

symptoms of respiratory disease (e.g., 

shortness of breath, cough, wheezing); 

history of tuberculosis; and smoking 

status and history; 

(ii) A physical examination with 

special emphasis on the respiratory 

system; 

(iii) A chest X-ray (posterior/anterior 

view; no less than 14 x 17 inches and 

no more than 16 x 17 inches at full 

inspiration), interpreted and classified 

according to the International Labour 

Organization (ILO) International 

Classification of Radiographs of 

Pneumoconioses by a NIOSH-certified 

‘‘B’’ reader, or an equivalent diagnostic 

study; 

(iv) A pulmonary function test to 

include forced vital capacity (FVC) and 

forced expiratory volume at one second 

(FEV1) and FEV1/FVC ratio, 

administered by a spirometry technician 

with current certification from a NIOSHapproved spirometry course; 

(v) Testing for latent tuberculosis 

infection; and 

(vi) Any other tests deemed 

appropriate by the PLHCP. 

(3) Periodic examinations. The 

employer shall make available medical 

examinations that include the 

procedures described in paragraph 

(h)(2) (except paragraph (h)(2)(v)) of this 

section at least every three years, or 

more frequently if recommended by the 

PLHCP. 

(4) Information provided to the 

PLHCP. The employer shall ensure that 

the examining PLHCP has a copy of this 

standard, and shall provide the PLHCP 

with the following information: 

(i) A description of the affected 

employee’s former, current, and 

anticipated duties as they relate to the 

employee’s occupational exposure to 

respirable crystalline silica; 

(ii) The employee’s former, current, 

and anticipated levels of occupational 

exposure to respirable crystalline silica; 

(iii) A description of any personal 

protective equipment used or to be used 

by the employee, including when and 

for how long the employee has used that 

equipment; and 

(iv) Information from records of 

employment-related medical 

examinations previously provided to the 

affected employee and currently within 

the control of the employer. 

(5) PLHCP’s written medical opinion. 

(i) The employer shall obtain a written 

medical opinion from the PLHCP within 

30 days of each medical examination 

performed on each employee. The 

written opinion shall contain: 

(A) A description of the employee’s 

health condition as it relates to exposure 

to respirable crystalline silica, including 

the PLHCP’s opinion as to whether the 

employee has any detected medical 

condition(s) that would place the 

employee at increased risk of material 

impairment to health from exposure to 

respirable crystalline silica; 

(B) Any recommended limitations 

upon the employee’s exposure to 

respirable crystalline silica or upon the 

use of personal protective equipment 

such as respirators; 

(C) A statement that the employee 

should be examined by an American 

Board Certified Specialist in Pulmonary 

Disease (‘‘pulmonary specialist’’) 

pursuant to paragraph (h)(6) of this 

section if the chest X-ray provided in 

accordance with this section is 

classified as 1/0 or higher by the ‘‘B’’ 

reader, or if referral to a pulmonary 

specialist is otherwise deemed 

appropriate by the PLHCP; and 

(D) A statement that the PLHCP has 

explained to the employee the results of 

the medical examination, including 

findings of any medical conditions 

related to respirable crystalline silica 

exposure that require further evaluation 

or treatment, and any recommendations 

related to use of protective clothing or 

equipment. 

(ii) The employer shall ensure that the 

PLHCP does not reveal to the employer 

specific findings or diagnoses unrelated 

to occupational exposure to respirable 

crystalline silica. 

(iii) The employer shall provide a 

copy of the PLHCP’s written medical 

opinion to the examined employee 

within two weeks after receiving it. 

(6) Additional examinations. (i) If the 

PLHCP’s written medical opinion 

indicates that an employee should be 

examined by a pulmonary specialist, the 

employer shall make available a medical 

examination by a pulmonary specialist 

within 30 days after receiving the 

PLHCP’s written medical opinion. 

(ii) The employer shall ensure that the 

examining pulmonary specialist is 

provided with all of the information that 

the employer is obligated to provide to 

the PLHCP in accordance with 

paragraph (h)(4) of this section. 

(iii) The employer shall obtain a 

written medical opinion from the 

pulmonary specialist that meets the 

requirements of paragraph (h)(5) (except 

paragraph (h)(5)(i)(C)) of this section. 

(i) Communication of respirable 

crystalline silica hazards to employees. 

(1) Hazard communication. The 

employer shall include respirable 

crystalline silica in the program 

established to comply with the Hazard 

Communication Standard (HCS) (29 

CFR 1910.1200). The employer shall 

ensure that each employee has access to 

labels on containers of crystalline silica 

and safety data sheets, and is trained in 

accordance with the provisions of HCS 

and paragraph (i)(2) of this section. The 

employer shall ensure that at least the 

following hazards are addressed: 

Cancer, lung effects, immune system 

effects, and kidney effects. 

(2) Employee information and 

training. (i) The employer shall ensure 

that each affected employee can 

demonstrate knowledge of at least the 

following: 

(A) Specific operations in the 

workplace that could result in exposure 

to respirable crystalline silica, 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56501 

especially operations where exposure 

may exceed the PEL; 

(B) Specific procedures the employer 

has implemented to protect employees 

from exposure to respirable crystalline 

silica, including appropriate work 

practices and use of personal protective 

equipment such as respirators and 

protective clothing; 

(C) The contents of this section; and 

(D) The purpose and a description of 

the medical surveillance program 

required by paragraph (h) of this 

section. 

(ii) The employer shall make a copy 

of this section readily available without 

cost to each affected employee. 

(j) Recordkeeping. (1) Air monitoring 

data. (i) The employer shall maintain an 

accurate record of all exposure 

measurement results used or relied on 

to characterize employee exposure to 

respirable crystalline silica, as 

prescribed in paragraph (d) of this 

section. 

(ii) This record shall include at least 

the following information: 

(A) The date of measurement for each 

sample taken; 

(B) The operation monitored; 

(C) Sampling and analytical methods 

used; 

(D) Number, duration, and results of 

samples taken; 

(E) Identity of the laboratory that 

performed the analysis; 

(F) Type of personal protective 

equipment, such as respirators, worn by 

the employees monitored; and 

(G) Name, social security number, and 

job classification of all employees 

represented by the monitoring, 

indicating which employees were 

actually monitored. 

(iii) The employer shall ensure that 

exposure records are maintained and 

made available in accordance with 29 

CFR 1910.1020. 

(2) Objective data. (i) The employer 

shall maintain an accurate record of all 

objective data relied upon to comply 

with the requirements of this section. 

(ii) This record shall include at least 

the following information: 

(A) The crystalline silica-containing 

material in question; 

(B) The source of the objective data; 

(C) The testing protocol and results of 

testing; 

(D) A description of the process, 

operation, or activity and how the data 

support the assessment; and 

(E) Other data relevant to the process, 

operation, activity, material, or 

employee exposures. 

(iii) The employer shall ensure that 

objective data are maintained and made 

available in accordance with 29 CFR 

1910.1020. 

(3) Medical surveillance. (i) The 

employer shall establish and maintain 

an accurate record for each employee 

covered by medical surveillance under 

paragraph (h) of this section. 

(ii) The record shall include the 

following information about the 

employee: 

(A) Name and social security number; 

(B) A copy of the PLHCP’s and 

pulmonary specialist’s written opinions; 

and 

(C) A copy of the information 

provided to the PLHCPs and pulmonary 

specialists as required by paragraph 

(h)(4) of this section. 

(iii) The employer shall ensure that 

medical records are maintained and 

made available in accordance with 29 

CFR 1910.1020. 

(k) Dates. (1) Effective date. This 

section shall become effective [INSERT 

DATE 60 DAYS AFTER PUBLICATION 

OF FINAL RULE IN THE Federal 

Register]. 

(2) Start-up dates. (i) All obligations 

of this section, except engineering 

controls required by paragraph (f) of this 

section and laboratory requirements in 

paragraph (d)(5)(ii) of this section, 

commence 180 days after the effective 

date. 

(ii) Engineering controls required by 

paragraph (f) of this section shall be 

implemented no later than one year 

after the effective date. 

(iii) Laboratory requirements in 

paragraph (d)(5)(ii) of this section 

commence two years after the effective 

date. 

Appendix A to § 1926.1053—Medical 

Surveillance Guidelines (NonMandatory) Introduction 

The purpose of this non-mandatory 

Appendix is to provide helpful information 

about complying with the medical 

surveillance provisions of the Respirable 

Crystalline Silica standard, as well as to 

provide other helpful recommendations and 

information. Medical screening and 

surveillance allow for early identification of 

exposure-related health effects in individual 

workers and groups of workers, respectively, 

so that actions can be taken to both avoid 

further exposure and prevent adverse health 

outcomes. Silica-related diseases can be fatal, 

encompass a variety of target organs, and 

may have public health consequences. Thus, 

medical surveillance of silica-exposed 

workers requires involvement of clinicians 

with thorough knowledge of silica-related 

health effects and a public health 

perspective. 

This Appendix is divided into four 

sections. Section I reviews silica-related 

diseases, appropriate medical responses, and 

public health responses. Section II outlines 

the components of the medical surveillance 

program for workers exposed to silica. 

Section III describes the roles and 

responsibilities of the clinician implementing 

the program and of other medical specialists 

and public health providers. Section IV 

provides additional resources. 

I. Recognition of Silica-Related Diseases 

Overview. Silica refers specifically to the 

compound silicon dioxide (SiO2). Silica is a 

major component of sand, rock, and mineral 

ores. Exposure to fine (respirable size) 

particles of crystalline forms of silica is 

associated with a number of adverse health 

effects. Exposure to respirable crystalline 

silica can occur in foundries, industries that 

have abrasive blasting operations, paint 

manufacturing, glass and concrete product 

manufacturing, brick making, china and 

pottery manufacturing, manufacturing of 

plumbing fixtures, and many construction 

activities including highway repair, masonry, 

concrete work, rock drilling, and 

tuckpointing. 

Silicosis is an irreversible, often disabling, 

and sometimes fatal fibrotic lung disease. 

Progression of silicosis can occur despite 

removal from further exposure. Diagnosis of 

silicosis requires a history of exposure to 

silica and radiologic findings characteristic of 

silica exposure. Three different presentations 

of silicosis (chronic, accelerated, and acute) 

have been defined. 

A. Chronic Silicosis. Chronic silicosis is 

the most common presentation of silicosis 

and usually occurs after at least 10 years of 

exposure to respirable crystalline silica. The 

clinical presentation of chronic silicosis is as 

follows: 

1. Symptoms—Shortness of breath and 

cough, although workers may not notice any 

symptoms early in the disease. Constitutional 

symptoms, such as fever, loss of appetite and 

fatigue, may indicate other diseases 

associated with silica exposure, such as 

mycobacterium tuberculosis infection (TB) or 

lung cancer. Workers with these symptoms 

should immediately receive further 

evaluation and treatment. 

2. Physical Examination—may be normal 

or disclose dry rales or rhonchi on lung 

auscultation. 

3. Spirometry—may be normal or may 

show only mild restriction or obstruction. 

4. Chest X-ray—classic findings are small, 

rounded opacities in the upper lung fields 

bilaterally. However, small irregular opacities 

and opacities in other lung areas can also 

occur. Rarely, ‘‘eggshell calcifications’’ are 

seen. 

5. Clinical Course—chronic silicosis in 

most cases is a slowly progressive disease. 

Accelerated and acute silicosis are much 

less common than chronic silicosis. 

However, it is critical to recognize all cases 

of accelerated and acute silicosis because 

these are life-threatening illnesses and 

because they are caused by substantial 

overexposures to respirable crystalline silica. 

Additionally, a case of acute or accelerated 

silicosis indicates a significant breakdown in 

prevention. Urgent communication with the 

employer is warranted to review exposure 

levels and protect other workers. 

B. Accelerated Silicosis. Accelerated 

silicosis occurs within 2–10 years of 

exposure and results from high levels of 

exposure to respirable crystalline silica. The 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56502 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

clinical presentation of accelerated silicosis 

is as follows: 

1. Symptoms—shortness of breath, cough, 

and sometimes sputum production. Workers 

with accelerated silicosis are at high risk of 

tuberculosis, atypical mycobacterial 

infections, and fungal superinfections. 

Constitutional symptoms, such as fever, 

weight loss, hemoptysis, and fatigue, may 

herald one of these infections or the onset of 

lung cancer. 

2. Physical Examination—rales, rhonchi, or 

other abnormal lung findings in relation to 

illnesses present. Clubbing of the digits, signs 

of heart failure, and cor pulmonale may be 

present in severe disease. 

3. Spirometry—restriction or mixed 

restriction/obstruction. 

4. Chest X-ray—small rounded and/or 

irregular opacities bilaterally. Large opacities 

and lung abscesses may indicate infections, 

lung cancer, or progression to complicated 

silicosis, also termed progressive massive 

fibrosis. 

5. Clinical Course—accelerated silicosis 

has a rapid, severe course. Referral to a 

physician who is American Board of Medical 

Specialties (ABMS)-Certified in Pulmonary 

Medicine should be made whenever the 

diagnosis of accelerated silicosis is being 

considered. Referral to the appropriate 

specialist should be made if signs or 

symptoms of tuberculosis, other silica-related 

infections, or lung cancer are observed. As 

noted above, the clinician should also alert 

the employer of the need for immediate 

review of exposure controls in the worksite 

in order to protect other workers. 

C. Acute Silicosis. Acute silicosis is a rare 

disease caused by inhalation of very high 

levels of respirable crystalline silica particles. 

The pathology is similar to alveolar 

proteinosis with lipoproteinaceous material 

accumulating in the alveoli. Acute silicosis 

develops rapidly, within a few months to less 

than 2 years of exposure, and is almost 

always fatal. The clinical presentation of 

acute silicosis is as follows: 

1. Symptoms—sudden, progressive, and 

severe shortness of breath. Constitutional 

symptoms are frequently present and include 

weight loss, fatigue, productive cough, 

hemoptysis, and pleuritic chest pain. 

2. Physical Examination—dyspnea at rest, 

cyanosis, decreased breath sounds, 

inspiratory rales, clubbing of the digits, and 

fever. 

3. Spirometry—restriction or mixed 

restriction/obstruction. 

4. Chest X-ray—diffuse haziness of the 

lungs bilaterally early in the disease. As the 

disease progresses, the ‘‘ground glass’’ 

appearance of interstitial fibrosis will appear. 

5. Clinical Course—workers with acute 

silicosis are at high risk of tuberculosis, 

atypical myco-baterial infections, and fungal 

superinfections. Because this disease is 

immediately life-threatening and indicates a 

profoundly high level of exposure, it 

constitutes an immediate medical and public 

health emergency. The worker must be 

urgently referred to a physician ABMScertified in Pulmonary Medicine. As noted 

above, the clinician should also alert the 

employer of the need for immediate exposure 

controls in the worksite in order to protect 

other workers. 

During medical surveillance examinations, 

clinicians should be alert for other silicarelated health outcomes as described below. 

D. Chronic Obstructive Pulmonary Disease 

(COPD). COPD, including chronic bronchitis 

and emphysema, has also been documented 

in silica-exposed workers, including those 

who do not develop silicosis. Periodic 

spirometry tests are performed to evaluate 

each worker for progressive changes 

consistent with the development of COPD. 

Additionally, collective spirometry data for 

groups of workers should be evaluated for 

declines in lung function, thereby providing 

a mechanism to detect insufficient silica 

control measures for groups of workers. 

E. Renal and Immune System. Silica 

exposure has been associated with several 

types of kidney disease, including 

glomerulonephritis, nephrotic syndrome, and 

end stage renal disease requiring dialysis. 

Silica exposure has also been associated with 

other autoimmune conditions, including 

progressive systemic sclerosis, systemic 

lupus erythematosus, and rheumatoid 

arthritis. Early studies noted an association 

between workers with silicosis and serologic 

markers for autoimmune diseases, including 

antinuclear antibodies, rheumatoid factor, 

and immune complexes (Jalloul and Banks, 

2007). 

F. Tuberculosis (TB). Silica-exposed 

workers with latent TB are 3–30 times more 

likely to develop active pulmonary TB 

infection (ATS, 1997; Rees, 2007). Although 

silica exposure does not cause TB infection, 

individuals with latent TB infection are at 

increased risk for activation of disease if they 

have higher levels of silica exposure, greater 

profusion of radiographic abnormalities, or a 

diagnosis of silicosis. Demographic 

characteristics are known to be associated 

with increased rates of latent TB infection. 

The clinician should review the latest CDC 

information on TB incidence rates and high 

risk populations. Additionally, silicaexposed workers are at increased risk for 

contracting atypical mycobacterial infections, 

including Mycobacterium aviumintracellulare and Mycobacterium kansaii. 

G. Lung Cancer. The International Agency 

for Research on Cancer (IARC, 1997) 

classified silica as Group I (carcinogenic to 

humans). Additionally, several studies have 

indicated that the combined effect of 

exposure to respirable crystalline silica and 

smoking was greater than additive (Brown, 

2009). 

II. Medical Surveillance 

Clinicians who manage silica medical 

surveillance programs should have a 

thorough understanding of the many silicarelated diseases and health effects outlined in 

Section I of this Appendix. At each clinical 

encounter, the clinician should consider 

silica-related health outcomes, with 

particular vigilance for acute and accelerated 

silicosis. The following guidance includes 

components of the medical surveillance 

examination that are required under the 

Respirable Crystalline Silica standard, noted 

below in italics. 

A. History. A complete work and medical 

history must be performed on the initial 

examination and every three years thereafter. 

Some of the information for this history must 

also be provided by the employer to the 

clinician. A detailed history is particularly 

important in the initial evaluation. Include 

the following components in this history: 

1. Previous and Current Employment 

a. Past, current, and anticipated exposures 

to respirable crystalline silica or other 

toxic substances 

b. Exposure to dust and other agents 

affecting the respiratory system 

c. Past, current, and anticipated work 

duties relating to exposures to respirable 

crystalline silica 

d. Personal protective equipment used, 

including respirators 

e. Previous medical surveillance 

2. Medical History 

a. All past and current medical conditions 

b. Review of symptoms, with particular 

attention to respiratory symptoms 

c. History of TB infection and/or positive 

test for latent TB 

d. History of other respiratory system 

dysfunction such as obstructive 

pulmonary disease or lung cancer 

e. History of kidney disease, connective 

tissue disease, and other immune 

disease/suppression 

f. Medications and allergies 

g. Smoking status and history 

f. Previous surgeries and hospitalizations 

B. Physical Examination. A physical 

examination must be performed on the initial 

examination and every three years thereafter. 

The physical examination must emphasize 

the respiratory system and should include an 

examination of the cardiac system and an 

extremity examination for clubbing, cyanosis, 

or edema. 

C. Tuberculosis (TB) Testing. Baseline 

testing for latent or active tuberculosis must 

be done on initial examination. Current CDC 

guidelines (www.cdc.gov) should be followed 

for the application and interpretation of 

Tuberculin skin tests (TST). The 

interpretation and documentation of TST 

reactions should be performed within 48 to 

72 hours of administration by trained 

clinicians. Individuals with a positive TST 

result and those with uncertain test results 

should be referred to a local public health 

specialist. Clinicians may use alternative TB 

tests, such as interferon-g release assays 

(IGRAs), if sensitivity and specificity are 

comparable to TST (Mazurek et al, 2010). 

Current CDC guidelines for acceptable tests 

for latent TB infection should be reviewed. 

Clinicians may perform periodic (e.g., 

annual) TB testing as appropriate, based on 

individual risk factors. The diagnosis of 

silicosis or exposure to silica for 25 years or 

more are indications for annual TB testing 

(ATS, 1997). Current CDC guidance on risk 

factors for TB should be reviewed 

periodically (www.cdc.gov). Workers who 

develop active pulmonary TB should be 

referred to the local public health 

department. Workers who have evidence of 

latent TB infection may be referred to the 

local public health department for evaluation 

and treatment. 

D. Spirometry. Spirometry must be 

performed on the initial examination and 

every three years thereafter. Spirometry 

provides information about individual 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 56503 

respiratory status, tracks an individual’s 

respiratory status over time, and is a valuable 

surveillance tool to track individual and 

group respiratory function. However, 

attention should be paid to quality control 

(ACOEM 2011; ATS/ERS Task Force 2005). 

Abnormal spirometry results warrant further 

clinical evaluation and possible work 

restrictions and/or treatment. 

E. Radiography. A chest roentgenogram, or 

an equivalent diagnostic study, must be 

performed on the initial examination and 

every three years thereafter. Chest 

radiography is necessary to diagnose 

silicosis, monitor the progression of silicosis, 

and identify associated conditions such as 

TB. An International Labor Organization 

(ILO) reading must be performed by a 

NIOSH-certified ‘‘B’’ reader. If the B reading 

indicates small opacities in a profusion of 

1/0 or higher, the worker must be referred to 

a physician who is certified by ABMS in 

pulmonary medicine. Medical imaging is 

currently in the process of transitioning from 

conventional film-based radiography to 

digital radiography systems. Until the ILO 

endorses the use of digital standards, 

conventional chest radiographs are needed 

for classification using the ILO system. 

Current ILO guidance on radiography for 

pneumoconioses and B-reading should be 

reviewed periodically on the ILO 

(www.ilo.org) or NIOSH (www.cdc.gov/

NIOSH) Web sites. 

F. Other Testing. It may be appropriate to 

include additional testing in a medical 

surveillance program such as baseline renal 

function tests (e.g., serum creatinine and 

urinalysis) and annual TST testing for silicaexposed workers. 

III. Roles and Responsibilities 

A. The Physician or other Licensed Health 

Care Professional (PLHCP). The PLHCP 

designation refers to an individual whose 

legally permitted scope of practice (i.e., 

license, registration, or certification) allows 

him or her to independently provide or be 

delegated the responsibility to provide some 

or all of the particular health care services 

required by the Respirable Crystalline Silica 

standard. The legally permitted scope of 

practice is determined by each State. Those 

licensed for independent practice may 

include physicians, nurse practitioners, or 

physician assistants, depending on the State. 

A medical surveillance program for workers 

exposed to silica should be directed by a 

health care professional licensed for 

independent practice. Health care 

professionals who provide clinical services 

for a silica medical surveillance program 

should have a thorough knowledge of the 

many silica-related diseases and health 

effects. Primary care practitioners who 

suspect a diagnosis of silicosis, advanced 

COPD, or other respiratory conditions 

causing impairment should promptly refer 

the affected individuals to a physician who 

is certified by ABMS in pulmonary medicine. 

1. The PLHCP is responsible for providing 

the employer with a written medical opinion 

within 30 days of an employee medical 

examination. The written opinion must 

include the following information: 

a. A description of the employee’s health 

condition as it relates to exposure to 

respirable crystalline silica, including the 

PLHCP’s opinion as to whether the employee 

has any detected medical condition(s) that 

would place the employee at increased risk 

of material impairment to health from further 

exposure to respirable crystalline silica. The 

employer should be notified if a health 

condition likely to have been caused by 

recent occupational exposure has been 

detected. Medical diagnoses and conditions 

that are not related to silica exposure must 

not be disclosed to the employer. Latent TB 

infection is not caused by silica exposure and 

must not be disclosed to the employer. All 

cases of active pulmonary TB should be 

referred to the Public Health Department. 

b. Any recommended limitations upon the 

employee’s exposure to respirable crystalline 

silica or upon the use of personal protective 

equipment such as respirators. Again, 

medical diagnoses not directly related to 

silica exposure must not be disclosed to the 

employer. Guidelines regarding ethics and 

confidentiality are available from 

professional practice organizations such as 

the American College of Occupational and 

Environmental Medicine. 

c. A statement that the employee should be 

examined by a physician who is certified by 

ABMS in pulmonary medicine, where such a 

referral is necessary. Referral to a pulmonary 

specialist is required for a chest X-ray B 

reading indicating small opacities in a 

profusion of 1/0 or higher, or if referral to a 

pulmonary specialist is otherwise deemed 

appropriate. A referral to the Public Health 

Department should not be disclosed to the 

employer. If necessary, a public health 

professional will contact the employer to 

discuss work-related conditions and/or to 

perform additional medical evaluations. 

d. A statement that the clinician has 

explained the results of the medical 

examination to the employee, including 

findings of any medical conditions related to 

respirable crystalline silica exposure that 

require further evaluation or treatment, and 

any recommendations related to use of 

protective clothing or equipment. 

2. State Reporting Requirements. Health 

care providers should be aware that some 

States require them to report cases of silicosis 

to the State Department of Health or to the 

State Department of the Environment. 

B. Medical Specialists. The Silica standard 

requires that all workers with chest X-ray B 

readings of 1/0 or higher be referred to an 

American Board Certified Specialist in 

Pulmonary Disease. The employer must 

obtain a written opinion from the specialist 

that includes the same required information 

as outlined above under IIIA1a, b, and d. 

Employers should receive any information 

concerning evidence of silica-related risk in 

their workplace (e.g., evidence of accelerated 

or acute silicosis tied to recent exposures), so 

that the employer can investigate and 

implement corrective measures if necessary. 

The employer must receive any information 

about an examined employee concerning 

work restrictions, including restrictions 

related to use of protective clothing or 

equipment. Employers must not receive other 

medical diagnoses or confidential health 

information. 

C. Public Health Providers. Clinicians 

should refer latent and active TB cases to 

their local Public Health Department. In 

addition to diagnosis and treatment of 

individual cases, public health providers 

promptly evaluate other potentially affected 

persons, including coworkers. Because silicaexposed workers are at increased risk of 

progression from latent to active TB, 

treatment of latent infection is recommended. 

The diagnosis of TB, acute or accelerated 

silicosis, or other silica-related diseases and 

infections should serve as sentinel findings. 

In addition to the local and state health 

departments, the National Institute of 

Occupational Safety and Health (NIOSH) can 

provide assistance upon request through 

their Health Hazard Evaluation program. 

IV. Resources and References 

American College of Occupational and 

Environmental Medicine (ACOEM), 

Position Statement. Medical Surveillance 

of Workers Exposed to Crystalline Silica. 

06/27/2005. 

ACOEM, Position Statement. Spirometry in 

the Occupational Health Setting. 04/05/ 

2011. 

American Thoracic Society (ATS): Medical 

Section of the American Lung 

Association. Adverse Effects of 

Crystalline Silica Exposure. Am J Respir 

Crit Care Med Vol 155. pp 761–765, 

1997. 

Brown T. Silica Exposure, Smoking, Silicosis 

and Lung Cancer—Complex Interactions. 

Occupational Medicine. 2009 59(2):89– 

95. 

Center for Disease Control and Prevention 

(CDC). Guide for Primary Health Care 

Providers: Targeted Tuberculin Testing 

and Treatment of Latent Tuberculosis 

Infection. 2005. 

Centers for Disease Control and Prevention. 

Screening for Tuberculosis and 

Tuberculosis Infection in High-Risk 

Populations. Recommendations of the 

Advisory Council for Elimination of 

Tuberculosis. MMWR 1995; 44(RR–11): 

18–34. 

International Agency for Research on Cancer 

(IARC) Working Group on the Evaluation 

of Carcinogenic Risks to Humans. Silica, 

Some Silicates, Coal Dust and Paraaramid Fibrils. Lyon, France. 1997. 

Jalloul AS, Banks DE. The Health Effects of 

Silica Exposure. In: Rom WN and 

Markowitz SB (Eds). Environmental and 

Occupational Medicine, 4th edition. 

Lippincott, Williams and Wilkins, 

Philadelphia. 2007. pp 365–387. 

Mazurek GH, Jereb J, Vernon A et al. Updated 

Guidelines for Using Interferon Gamma 

Release Assays to Detect Mycobacterium 

tuberculosis Infection—United States, 

2010. Morbidity and Mortality Weekly 

Report (MMWR), 6/25/10; 59(RR05):1– 

25. 

Miller MR et al, Standardisation of 

spirometry from SERIES ‘‘ATS/ERS 

TASK FORCE: STANDARDISATION OF 

LUNG FUNCTION TESTING’’ Edited by 

V Brusasco, R Crapo and G Viegi. Eur 

Respir J 2005; 26:319–338. 

National Institute of Occupational Safety and 

Health (NIOSH) B reader Program. 

Access online for more information on 

interpretation of X-rays for silicosis and 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

56504 Federal Register / Vol. 78, No. 177 / Thursday, September 12, 2013 / Proposed Rules 

a list of certified B-readers. http://

www.cdc.gov/niosh/topics/

chestradiography/breader-info.html 

NIOSH Hazard Review: Health Effects of 

Occupational Exposure to Respirable 

Crystalline Silica; Department of Health 

and Human Services, CDC, NIOSH, April 

2002. 

Occupational Health Program for Exposure to 

Crystalline Silica in the Industrial Sand 

Industry. National Industrial Sand 

Association, 2nd ed. 2010. 

Rees D, Murray J. Silica, silicosis and 

tuberculosis. Int J Tuberc Lung Dis 

11(5):474–484. 

Screening and Surveillance of workers 

exposed to mineral dust; Gregory R 

Wagner, Director, Division of Respiratory 

Diseases, NIOSH, Morgantown, WV, 

U.S.A.; WHO, Geneva 1996. 

[FR Doc. 2013–20997 Filed 9–11–13; 8:45 a.m.] 

BILLING CODE 4510–26–P 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2