6560-50-P 

ENVIRONMENTAL PROTECTION AGENCY 

40 CFR Part 63 

[EPA-HQ-OAR-2010-0600; FRL- ] 

RIN 2060–AO91 

National Emission Standards for Hazardous Air Pollutant 

Emissions: Hard and Decorative Chromium Electroplating and 

Chromium Anodizing Tanks; Group I Polymers and Resins; Marine 

Tank Vessel Loading Operations; Pharmaceuticals Production; The 

Printing and Publishing Industry; and Steel Pickling--HCl 

Process Facilities and Hydrochloric Acid Regeneration Plants 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Proposed rule; and Supplemental Notice of Proposed 

Rulemaking. 

SUMMARY: This action proposes how EPA will address the residual 

risk and technology reviews conducted for two national emission 

standards for hazardous air pollutants (NESHAP), and this action 

is a supplemental notice of proposed rulemaking for an October 

2008 action that proposed how EPA would address the residual 

risk and technology reviews for four NESHAP. The six NESHAP 

include 16 source categories. This action proposes to modify 

the existing emissions standards for eight source categories in 

three of the six NESHAP to address certain emission sources not 

currently regulated under these standards. It also proposes for 

all six NESHAP to address provisions related to emissions during 

periods of startup, shutdown, and malfunction. Finally, this 
Page 2 of 387 

action proposes changes to two of the six NESHAP to correct 

editorial errors, make clarifications, or address issues with 

implementation or determining compliance. 

DATES: Comments. Comments must be received on or before 

[INSERT DATE 45 DAYS FROM DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. Under the Paperwork Reduction Act, comments on the 

information collection provisions are best assured of having 

full effect if the Office of Management and Budget (OMB) 

receives a copy of your comments on or before [INSERT DATE 30 

DAYS FROM DATE OF PUBLICATION IN THE FEDERAL REGISTER].

Public Hearing. We will hold a public hearing on [INSERT 

DATE 15 DAYS FROM DATE OF PUBLICATION IN THE FEDERAL REGISTER]. 

Persons requesting to speak at the public hearing must contact 

EPA by [INSERT DATE 10 DAYS FROM DATE OF PUBLICATION IN THE 

FEDERAL REGISTER]. 

ADDRESSES: Comments. Submit your comments, identified by 

Docket ID No. EPA-HQ-OAR-2010-0600, by one of the following 

methods: 

• www.regulations.gov: Follow the on-line instructions for 

submitting comments. 

• E-mail: a-and-r-docket@epa.gov. Attention Docket ID No. 

EPA-HQ-OAR-2010-0600. 

• Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR2010-0600. 
Page 3 of 387 

• Mail: U.S. Postal Service, send comments to: EPA Docket 

Center, EPA West (Air Docket), Attention Docket ID No. EPAHQ-OAR-2010-0600, U.S. Environmental Protection Agency, 

Mailcode: 2822T, 1200 Pennsylvania Ave., NW, Washington, 

DC 20460. Please include a total of two copies. In 

addition, please mail a copy of your comments on the 

information collection provisions to the Office of 

Information and Regulatory Affairs, Office of Management 

and Budget (OMB), Attn: Desk Officer for EPA, 725 17th

Street, NW, Washington, DC 20503. 

• Hand Delivery: U.S. Environmental Protection Agency, EPA 

West (Air Docket), Room 3334, 1301 Constitution Ave., NW, 

Washington, DC 20004. Attention Docket ID No. EPA-HQ-OAR2010-0600. Such deliveries are only accepted during the 

Docket’s normal hours of operation, and special 

arrangements should be made for deliveries of boxed 

information. 

Instructions. Direct your comments to Docket ID No. EPAHQ-OAR-2010-0600. EPA’s policy is that all comments received 

will be included in the public docket without change and may be 

made available online at www.regulations.gov, including any 

personal information provided, unless the comment includes 

information claimed to be confidential business information 

(CBI) or other information whose disclosure is restricted by 
Page 4 of 387 

statute. Do not submit information that you consider to be CBI 

or otherwise protected through www.regulations.gov or e-mail. 

The www.regulations.gov website is an “anonymous access” system, 

which means EPA will not know your identity or contact 

information unless you provide it in the body of your comment. 

If you send an e-mail comment directly to EPA without going 

through www.regulations.gov, your e-mail address will be 

automatically captured and included as part of the comment that 

is placed in the public docket and made available on the 

Internet. If you submit an electronic comment, EPA recommends 

that you include your name and other contact information in the 

body of your comment and with any disk or CD-ROM you submit. If 

EPA cannot read your comment due to technical difficulties and 

cannot contact you for clarification, EPA may not be able to 

consider your comment. Electronic files should avoid the use of 

special characters, any form of encryption, and be free of any 

defects or viruses. For additional information about EPA’s 

public docket, visit the EPA Docket Center homepage at 

http://www.epa.gov/epahome/dockets.htm. 

Docket. The EPA has established a docket for this 

rulemaking under Docket ID No. EPA-HQ-OAR-2010-0600. All 

documents in the docket are listed in the www.regulations.gov

index. Although listed in the index, some information is not 

publicly available, e.g., CBI or other information whose 
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disclosure is restricted by statute. Certain other material, 

such as copyrighted material, is not placed on the Internet and 

will be publicly available only in hard copy. Publicly 

available docket materials are available either electronically 

in www.regulations.gov or in hard copy at the EPA Docket Center, 

EPA West, Room 3334, 1301 Constitution Ave., NW, Washington, DC. 

The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., 

Monday through Friday, excluding legal holidays. The telephone 

number for the Public Reading Room is (202) 566-1744, and the 

telephone number for the EPA Docket Center is (202) 566-1742. 

Public Hearing. We will hold a public hearing concerning 

this proposed rule on [INSERT DATE 15 DAYS FROM DATE OF 

PUBLICATION IN THE FEDERAL REGISTER], from 9 a.m. to 7 p.m. 

Persons interested in presenting oral testimony at the hearing 

should contact Ms. Mary Tom Kissell, Sector Policies and 

Programs Division (E143-01), Office of Air Quality Planning and 

Standards, U.S. Environmental Protection Agency, Research 

Triangle Park, NC 27711, telephone number, (919) 541–4516, by 

[INSERT DATE 10 DAYS FROM DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. The public hearing will be held at the U.S. 

Environmental Protection Agency – Research Triangle Park Campus, 

109 T.W. Alexander Drive, Research Triangle Park, NC 27709. If 

no one requests to speak at the public hearing by [INSERT DATE 

10 DAYS FROM DATE OF PUBLICATION IN THE FEDERAL REGISTER], then 
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the public hearing will be cancelled and a notification of 

cancellation posted on the following Web site: 

http://www.epa.gov/ttn/oarpg/t3main.html. 

FOR FURTHER INFORMATION CONTACT: For questions about this 

proposed action, contact Ms. Mary Tom Kissell, Sector Policies 

and Programs Division (E143-01), Office of Air Quality Planning 

and Standards, U.S. Environmental Protection Agency, Research 

Triangle Park, NC 27711, telephone (919) 541-4516; fax number: 

(919) 541-0246; and e-mail address: kissell.mary@epa.gov. For 

specific information regarding the risk modeling methodology, 

contact Ms. Elaine Manning, Health and Environmental Impacts 

Division (C539-02), Office of Air Quality Planning and 

Standards, U.S. Environmental Protection Agency, Research 

Triangle Park, NC 27711; telephone number: (919) 541–5499; fax 

number: (919) 541–0840; and e-mail address: 

manning.elaine@epa.gov. For information about the applicability 

of these six NESHAP to a particular entity, contact the 

appropriate person listed in Table 1 to this preamble. 

Table 1. List of EPA Contacts for the NESHAP Addressed in this 

Proposed Action 

NESHAP for: OECA Contact1

 OAQPS Contact2

Hard and 

Decorative 

Chromium 

Electroplating 

and Chromium 

Anodizing Tanks 

Scott Throwe, 

(202) 564–7013, 

throwe.scott@epa.gov 

Phil Mulrine, 

(919) 541-5289, 

mulrine.phil@epa.gov 

Group I Scott Throwe, Randy McDonald, 
Page 7 of 387 

Polymers and 

Resins 

Production 

(202) 564–7013, 

throwe.scott@epa.gov 

(919) 541–5402, 

mcdonald.randy@epa.gov

Marine Vessel 

Loading 

Operations 

Maria Malave, 

(202) 564–7027, 

malave.maria@epa.gov 

Steve Shedd, 

(919) 541-5397, 

shedd.steve@epa.gov 

Pharmaceuticals 

Production 

Marcia Mia, 

(202) 564–7042, 

mia.marcia@epa.gov

Randy McDonald, 

(919) 541–5402, 

mcdonald.randy@epa.gov

Printing and 

Publishing 

Industry 

Len Lazarus, 

(202) 564–6369, 

lazarus.leonard@epa.gov

David Salman, 

(919) 541–0859, 

salman.dave@epa.gov

Steel Pickling 

– HCl Process 

Facilities and 

Hydrochloric 

Acid 

Regeneration 

Plants 

Maria Malave, 

(202) 564–7027, 

malave.maria@epa.gov 

Phil Mulrine, 

(919) 541-5289, 

mulrine.phil@epa.gov

1

 OECA stands for EPA’s Office of Enforcement and Compliance 

Assurance. 

2

 OAQPS stands for EPA’s Office of Air Quality Planning and 

Standards. 

SUPPLEMENTARY INFORMATION: 

I. Preamble Acronyms and Abbreviations 

 Several acronyms and terms used to describe industrial 

processes, data inventories, and risk modeling are included in 

this preamble. While this may not be an exhaustive list, to 

ease the reading of this preamble and for reference purposes, 

the following terms and acronyms are defined here: 

AERMOD – The air dispersion model used by the HEM-3 model 

AEGL - Acute Exposure Guideline Levels 

ANPRM - Advance Notice of Proposed Rulemaking 
Page 8 of 387 

ASTM - an international standards organization that 

develops and publishes voluntary consensus technical standards 

ATCM – Airborne Toxics Control Measure 

ATSDR – Agency for Toxic Substances and Disease Registry 

BACT - Best Available Control Technology 

BID – Background Information Document 

CalEPA – California Environmental Protection Agency 

CARB – California Air Resources Board 

CAA – Clean Air Act 

CBI – Confidential Business Information 

CEEL - Community Emergency Exposure Levels 

CIIT - Chemical Industry Institute of Toxicology 

CFR – Code of Federal Regulations 

CMP - Composite Mesh Pad 

CO – Carbon Monoxide 

CO2 – Carbon Dioxide 

D/F – Dioxin/Furan 

EED - Emission Elimination Device 

EPA – Environmental Protection Agency 

EPS - Eco Pickled Surface 

ERPG - Emergency Response Planning Guidelines 

HAP – Hazardous Air Pollutants 

HCl – Hydrochloric Acid 

HI – Hazard Index 
Page 9 of 387 

HEM-3 – Human Exposure Model version 3 

HEPA – High Efficiency Particulate Air 

HON – Hazardous Organic National Emissions Standards for 

Hazardous Air Pollutants 

HQ – Hazard Quotient 

ICR – Information Collection Request 

IRIS – Integrated Risk Information System 

Km – Kilometer 

LAER - Lowest Achievable Emission Rate 

MACT – Maximum Achievable Control Technology 

MACT Code – A code within the NEI used to identify 

processes included in a source category 

mg/dscm - Milligrams per Dry Standard Cubic Meter 

MIR – Maximum Individual Risk 

MTVLO - Marine Tank Vessel Loading Operations 

NAC/AEGL Committee - National Advisory Committee for Acute 

Exposure Guideline Levels for Hazardous Substances 

NAICS – North American Industry Classification System 

NAS - National Academy of Sciences 

NATA - National Air Toxics Assessment 

NESHAP – National Emissions Standards for Hazardous Air 

Pollutants 

NEI – National Emissions Inventory 

NOX – Nitrogen Oxide 
Page 10 of 387 

NRC – National Research Council 

NSR - New Source Review 

NTTAA - National Technology Transfer and Advancement Act 

OECA – Office of Enforcement and Compliance Assurance 

OLD – Organic Liquids Distribution 

OMB – Office of Management and Budget 

PB-HAP – Hazardous air pollutants known to be persistent 

and bio-accumulative in the environment 

PFC - Perfluorinated Chemical 

PFOS - Perfluorooctane Sulfonate 

PM – Particulate Matter 

POM – Polycyclic Organic Matter 

RACT - Reasonably Available Control Technology 

RBLC - RACT/BACT/LAER Clearinghouse 

REL - CalEPA Chronic Reference Exposure Level 

RFA - Regulatory Flexibility Act 

RfC – Reference Concentration 

RfD – Reference Dose 

RTR – Residual Risk and Technology Review 

SAB - Science Advisory Board 

SCC – Source Classification Codes 

SCS - Smooth Clean Surface 

SF3 - 2000 Census of Population and Housing Summary File 3 

SO2 – Sulfur Dioxide 
Page 11 of 387 

SOP – Standard Operating Procedures 

SSM – Startup, Shutdown, and Malfunction 

TOSHI – Target Organ-Specific Hazard Index 

TPY – Tons Per Year 

TRIM – Total Risk Integrated Modeling System 

TTN – Technology Transfer Network 

UF - Uncertainty Factor 

UMRA - Unfunded Mandates Reform Act 

URE – Unit Risk Estimate 

VOC – Volatile Organic Compounds 

WAFS - Wetting Agent/Fume Suppressant 

WCSC - Waterborne Commerce Statistics Center 

WWW – Worldwide Web 

II. General Information 

A. Does this action apply to me?

 The regulated industrial source categories that are the 

subject of this proposal are listed in Table 2 to this preamble. 

Table 2 is not intended to be exhaustive, but rather provides a 

guide for readers regarding entities likely to be affected by 

the proposed action for the source categories listed. These 

standards, and any changes considered in this rulemaking, would 

be directly applicable to sources as a Federal program. Thus, 

Federal, State, local, and tribal government entities are not 
Page 12 of 387 

affected by this proposed action. The regulated categories 

affected by this proposed action include: 

Table 2. NESHAP and Industrial Source Categories Affected by 

this Proposed Action 

NESHAP and Source Category NAICS code1

 MACT code2

Chromium Anodizing 

Tanks 

332813 1607 

Decorative Chromium 

Electroplating 

332813 1610 

Chromium 

Electroplating 

Hard Chromium 

Electroplating 

332813 1615 

Butyl Rubber 

Production 

325212 1307 

Epichlorohydrin 

Elastomers 

Production 

325212 1311 

Ethylene Propylene 

Rubber Production 

325212 1313 

HypalonTM

Production3

325212 1315 

Neoprene Production 325212 1320 

Nitrile Butadiene 

Rubber Production 

325212 1321 

Polybutadiene 

Rubber 

Production 

325212 1325 

Polysulfide Rubber 

Production3

325212 1332 

Group I 

Polymers and 

Resins 

Styrene Butadiene 

Rubber and Latex 

Production 

325212 1339 

Marine Vessel Loading Operations 4883 0603 

Pharmaceuticals Production 3254 1201 

Printing and Publishing Industry 32311 0714 

Steel Pickling – HCl Process 

Facilities And Hydrochloric Acid 

Regeneration Plants 

3311, 3312 0310 

1

 North American Industry Classification System 

2

 Maximum Achievable Control Technology 
Page 13 of 387 

3

 There are no longer any operating facilities in either the 

HypalonTM or Polysulfide Rubber source categories. Therefore, 

this proposal does not address these source categories. 

B. Where can I get a copy of this document and other related 

information?

In addition to being available in the docket, an electronic 

copy of this proposal will also be available on the World Wide 

Web (WWW) through the Technology Transfer Network (TTN). 

Following signature by the EPA Administrator, a copy of this 

proposed action will be posted on the TTN’s policy and guidance 

page for newly proposed or promulgated rules at the following 

address: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The TTN 

provides information and technology exchange in various areas of 

air pollution control. 

Additional information is available on the residual risk 

and technology review (RTR) web page at 

http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. This information 

includes source category descriptions and detailed emissions and 

other data that were used as inputs to the risk assessments. 

C. What should I consider as I prepare my comments for EPA?

 Submitting CBI. Do not submit information containing CBI 

to EPA through www.regulations.gov or e-mail. Clearly mark the 

part or all of the information that you claim to be CBI. For 

CBI information on a disk or CD ROM that you mail to EPA, mark 

the outside of the disk or CD ROM as CBI and then identify 
Page 14 of 387 

electronically within the disk or CD ROM the specific 

information that is claimed as CBI. In addition to one complete 

version of the comment that includes information claimed as CBI, 

a copy of the comment that does not contain the information 

claimed as CBI must be submitted for inclusion in the public 

docket. If you submit a CD ROM or disk that does not contain 

CBI, mark the outside of the disk or CD ROM clearly that it does 

not contain CBI. Information not marked as CBI will be included 

in the public docket and EPA’s electronic public docket without 

prior notice. Information marked as CBI will not be disclosed 

except in accordance with procedures set forth in 40 CFR part 2. 

Send or deliver information identified as CBI only to the 

following address: Roberto Morales, OAQPS Document Control 

Officer (C404-02), Office of Air Quality Planning and Standards, 

U.S. Environmental Protection Agency, Research Triangle Park, NC 

27711, Attention Docket ID No. EPA-HQ-OAR-2010-0600. 

D. How is this document organized?

 The information in this preamble is organized as follows: 

I. Preamble Acronyms and Abbreviations 

II. General Information 

A. Does this action apply to me? 

B. Where can I get a copy of this document and other related 

information? 

C. What should I consider as I prepare my comments for EPA? 

D. How is this document organized? 

III. Background 

 A. What is the statutory authority for this action? 

 B. How did we consider the risk results in making decisions 

for this proposal? 
Page 15 of 387 

 C. What other actions are we addressing in this proposal? 

 D. What specific RTR actions have previously been taken for 

these source categories? 

IV. Analyses Performed 

A. How did we estimate risk posed by the source categories? 

B. How did we perform the technology review? 

C. How did we perform the analyses for the other actions 

 being proposed? 

V. Analyses Results and Proposed Decisions 

 A. What are the results and proposed decisions for the 

Chromium Electroplating source categories? 

 B. What are the results and proposed decisions for the Group 

I Polymers and Resins Production source categories? 

 C. What are the results and proposed decisions for Marine 

Tank Vessel Loading Operations source category? 

 D. What are the results and proposed decisions for the 

Pharmaceuticals Production source category? 

 E. What are the results and proposed decisions for the 

Printing and Publishing Industry source category? 

 F. What are the results and proposed decisions for Steel 

Pickling-HCl Process Facilities and Hydrochloric Acid 

Regeneration Plants source category? 

VI. Summary of Proposed Actions 

A. What actions are we proposing as a result of the 

technology reviews? 

B. What actions are we proposing as a result of the residual 

risk reviews? 

C. What other actions are we proposing? 

VII. Request for Comments 

VIII. Submitting Data Corrections 

IX. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and Review 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments 

G. Executive Order 13045: Protection of Children from 

Environmental Health Risks and Safety Risks 

H. Executive Order 13211: Actions Concerning Regulations 

That Significantly Affect Energy Supply, Distribution, or 

Use 

I. National Technology Transfer and Advancement Act 

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and LowIncome Populations 
Page 16 of 387 

III. Background 

A. What is the statutory authority for this action? 

Section 112 of the Clean Air Act (CAA) establishes a twostage regulatory process to address emissions of hazardous air 

pollutants (HAP) from stationary sources. In the first stage, 

after EPA has identified categories of sources emitting one or 

more of the HAP listed in section 112(b) of the CAA, section 

112(d) of the CAA calls for us to promulgate NESHAP for those 

sources. “Major sources” are those that emit or have the 

potential to emit any single HAP at a rate of 10 tons per year 

(TPY) or more of a single HAP or 25 TPY or more of any 

combination of HAP. For major sources, these technology-based 

standards must reflect the maximum degree of emission reductions 

of HAP achievable (after considering cost, energy requirements, 

and non-air quality health and environmental impacts) and are 

commonly referred to as maximum achievable control technology 

(MACT) standards. 

MACT standards are to reflect application of measures, 

processes, methods, systems, or techniques, including, but not 

limited to, measures which, (A) reduce the volume of or 

eliminate pollutants through process changes, substitution of 

materials or other modifications, (B) enclose systems or 

processes to eliminate emissions, (C) capture or treat 
Page 17 of 387 

pollutants when released from a process, stack, storage, or 

fugitive emissions point, (D) are design, equipment, work 

practice, or operational standards (including requirements for 

operator training or certification), or (E) are a combination of 

the above. CAA section 112(d)(2)(A)-(E). The MACT standard may 

take the form of a design, equipment, work practice, or 

operational standard where EPA first determines either that (A) 

a pollutant cannot be emitted through a conveyance designed and 

constructed to emit or capture the pollutant, or that any 

requirement for or use of such a conveyance would be 

inconsistent with law, or (B) the application of measurement 

methodology to a particular class of sources is not practicable 

due to technological and economic limitations. CAA sections 

112(h)(1)-(2). 

The MACT “floor” is the minimum control level allowed for 

MACT standards promulgated under CAA section 112(d)(3), and may 

not be based on cost considerations. For new sources, the MACT 

floor cannot be less stringent than the emission control that is 

achieved in practice by the best-controlled similar source. The 

MACT floors for existing sources can be less stringent than 

floors for new sources, but they cannot be less stringent than 

the average emission limitation achieved by the best-performing 

12 percent of existing sources in the category or subcategory 

(or the best-performing five sources for categories or 
Page 18 of 387 

subcategories with fewer than 30 sources). In developing MACT 

standards, we must also consider control options that are more 

stringent than the floor. We may establish standards more 

stringent than the floor based on the consideration of the cost 

of achieving the emissions reductions, any non-air quality 

health and environmental impacts, and energy requirements. 

The EPA is then required to review these technology-based 

standards and to revise them “as necessary (taking into 

account developments in practices, processes, and control 

technologies)” no less frequently than every 8 years, under 

CAA section 112(d)(6). In conducting this review, EPA is not 

obliged to completely recalculate the prior MACT determination. 

NRDC v. EPA, 529 F.3d 1077, 1084 (District of Columbia Circuit, 

2008). 

The second stage in standard-setting focuses on reducing 

any remaining “residual” risk according to CAA section 112(f). 

This provision requires, first, that EPA prepare a Report to 

Congress discussing (among other things) methods of calculating 

risk posed (or potentially posed) by sources after 

implementation of the MACT standards, the public health 

significance of those risks, the means and costs of controlling 

them, the actual health effects to persons in proximity of 

emitting sources, and the recommendations regarding legislation 

of such remaining risk. EPA prepared and submitted this report 
Page 19 of 387 

(Residual Risk Report to Congress, EPA–453/R–99–001) in March 

1999. Congress did not act in response to the report, thereby 

triggering EPA’s obligation under CAA section 112(f)(2) to 

analyze and address residual risk. 

CAA section 112(f)(2) requires us to determine for source 

categories subject to certain MACT standards, whether the 

emissions standards provide an ample margin of safety to protect 

public health. If the MACT standards for HAP “classified as a 

known, probable, or possible human carcinogen “do not reduce 

lifetime excess cancer risks to the individual most exposed to 

emissions from a source in the category or subcategory to less 

than 1-in-1 million,” EPA must promulgate residual risk 

standards for the source category (or subcategory) as necessary 

to provide an ample margin of safety to protect public health. 

In doing so, EPA may adopt standards equal to existing MACT 

standards if EPA determines that the existing standards are 

sufficiently protective. NRDC v. EPA, 529 F.3d 1077, 1083 

(District of Columbia Circuit, 2008). (“If EPA determines that 

the existing technology-based standards provide an ‘ample margin 

of safety,’ then the Agency is free to readopt those standards 

during the residual risk rulemaking.”) EPA must also adopt more 
Page 20 of 387 

stringent standards, if necessary, to prevent an adverse 

environmental effect,1

 but must consider cost, energy, safety, 

and other relevant factors in doing so. 

Section 112(f)(2) of the CAA expressly preserves our use of 

a two-step process for developing standards to address any 

residual risk and our interpretation of “ample margin of safety” 

developed in the National Emission Standards for Hazardous Air 

Pollutants: Benzene Emissions from Maleic Anhydride Plants, 

Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene 

Equipment Leaks, and Coke By-Product Recovery Plants (Benzene 

NESHAP) (54 FR 38044, September 14, 1989). The first step in 

this process is the determination of acceptable risk. The 

second step provides for an ample margin of safety to protect 

public health, which is the level at which the standards are set 

(unless a more stringent standard is required to prevent, taking 

into consideration costs, energy, safety, and other relevant 

factors, an adverse environmental effect). 

The terms “individual most exposed,” “acceptable level,” 

and “ample margin of safety” are not specifically defined in the 

CAA. However, CAA section 112(f)(2)(B) preserves the 

interpretation set out in the Benzene NESHAP, and the United 

 

1 “Adverse environmental effect” is defined in CAA section 112(a)(7) as 

any significant and widespread adverse effect, which may be reasonably 

anticipated to wildlife, aquatic life, or natural resources, including 

adverse impacts on populations of endangered or threatened species or 

significant degradation of environmental qualities over broad areas. 
Page 21 of 387 

States Court of Appeals for the District of Columbia Circuit in 

NRDC v. EPA, 529 F.3d 1077, concluded that EPA’s interpretation 

of subsection 112(f)(2) is a reasonable one. See NRDC v. EPA, 

529 F.3d at 1083 (District of Columbia Circuit, “[S]ubsection 

112(f)(2)(B) expressly incorporates EPA’s interpretation of the 

Clean Air Act from the Benzene standard, complete with a 

citation to the Federal Register”). (District of Columbia 

Circuit 2008). See also, A Legislative History of the Clean Air 

Act Amendments of 1990, volume 1, p. 877 (Senate debate on 

Conference Report). We notified Congress in the Residual Risk 

Report to Congress that we intended to use the Benzene NESHAP 

approach in making CAA section 112(f) residual risk 

determinations (EPA–453/R–99–001, p. ES–11). 

In the Benzene NESHAP, we stated as an overall objective: 

* * * in protecting public health with an ample margin of 

safety, we strive to provide maximum feasible protection 

against risks to health from hazardous air pollutants by 

(1) protecting the greatest number of persons possible to 

an individual lifetime risk level no higher than 

approximately 1-in-1 million; and (2) limiting to no higher 

than approximately 1-in-10 thousand [i.e., 100-in-1 

million] the estimated risk that a person living near a 

facility would have if he or she were exposed to the 

maximum pollutant concentrations for 70 years. 
Page 22 of 387 

The Agency also stated that, “The EPA also considers 

incidence (the number of persons estimated to suffer cancer or 

other serious health effects as a result of exposure to a 

pollutant) to be an important measure of the health risk to the 

exposed population. Incidence measures the extent of health 

risk to the exposed population as a whole, by providing an 

estimate of the occurrence of cancer or other serious health 

effects in the exposed population.” The Agency went on to 

conclude that “estimated incidence would be weighed along with 

other health risk information in judging acceptability.” As 

explained more fully in our Residual Risk Report to Congress, 

EPA does not define “rigid line[s] of acceptability,” but 

considers rather broad objectives to be weighed with a series of 

other health measures and factors (EPA–453/R–99–001, p. ES–11). 

The determination of what represents an “acceptable” risk is 

based on a judgment of “what risks are acceptable in the world 

in which we live” (Residual Risk Report to Congress, p. 178, 

quoting the Vinyl Chloride decision at 824 F.2d 1165) 

recognizing that our world is not risk-free. 

In the Benzene NESHAP, we stated that “EPA will generally 

presume that if the risk to [the maximum exposed] individual is 

no higher than approximately 1-in-10 thousand, that risk level 

is considered acceptable.” 54 FR 38045. We discussed the 

maximum individual lifetime cancer risk as being “the estimated 
Page 23 of 387 

risk that a person living near a plant would have if he or she 

were exposed to the maximum pollutant concentrations for 70 

years.” Id. We explained that this measure of risk “is an 

estimate of the upper bound of risk based on conservative 

assumptions, such as continuous exposure for 24 hours per day 

for 70 years.” Id. We acknowledge that maximum individual 

lifetime cancer risk “does not necessarily reflect the true 

risk, but displays a conservative risk level which is an upperbound that is unlikely to be exceeded.” Id. 

Understanding that there are both benefits and limitations 

to using maximum individual lifetime cancer risk as a metric for 

determining acceptability, we acknowledged in the 1989 Benzene 

NESHAP that “consideration of maximum individual risk * * * must 

take into account the strengths and weaknesses of this 

measure of risk.” Id. Consequently, the presumptive risk level 

of 100-in-1 million (1-in-10 thousand) provides a benchmark for 

judging the acceptability of maximum individual lifetime cancer 

risk, but does not constitute a rigid line for making that 

determination. 

The Agency also explained in the 1989 Benzene NESHAP the 

following: “In establishing a presumption for MIR [maximum 

individual cancer risk], rather than a rigid line for 

acceptability, the Agency intends to weigh it with a series of 

other health measures and factors. These include the overall 
Page 24 of 387 

incidence of cancer or other serious health effects within the 

exposed population, the numbers of persons exposed within each 

individual lifetime risk range and associated incidence within, 

typically, a 50-kilometer (km) exposure radius around 

facilities, the science policy assumptions and estimation 

uncertainties associated with the risk measures, weight of the 

scientific evidence for human health effects, other quantified 

or unquantified health effects, effects due to co-location of 

facilities, and co-emission of pollutants.” Id.

In some cases, these health measures and factors taken 

together may provide a more realistic description of the 

magnitude of risk in the exposed population than that provided 

by maximum individual lifetime cancer risk alone. As explained 

in the Benzene NESHAP, “[e]ven though the risks judged 

“acceptable” by EPA in the first step of the Vinyl Chloride 

inquiry are already low, the second step of the inquiry, 

determining an “ample margin of safety,” again includes 

consideration of all of the health factors, and whether to 

reduce the risks even further.” In the ample margin of safety 

decision process, the Agency again considers all of the health 

risks and other health information considered in the first step. 

Beyond that information, additional factors relating to the 

appropriate level of control will also be considered, including 

costs and economic impacts of controls, technological 
Page 25 of 387 

feasibility, uncertainties, and any other relevant factors. 

Considering all of these factors, the Agency will establish the 

standard at a level that provides an ample margin of safety to 

protect the public health, as required by CAA section 112(f). 

54 FR 38046. 

B. How did we consider the risk results in making decisions

for this proposal?

As discussed in section III.A. of this preamble, we apply a 

two-step process for developing standards to address residual 

risk. In the first step, EPA determines if risks are 

acceptable. This determination “considers all health 

information, including risk estimation uncertainty, and includes 

a presumptive limit on maximum individual lifetime [cancer] risk 

(MIR)2

 of approximately 1-in-10 thousand [i.e., 100-in-1 

million].” 54 FR 38045. In the second step of the process, EPA 

sets the standard at a level that provides an ample margin of 

safety “in consideration of all health information, including 

the number of persons at risk levels higher than approximately 

1-in-1 million, as well as other relevant factors, including 

costs and economic impacts, technological feasibility, and other 

factors relevant to each particular decision.” Id. 

 

2 Although defined as “maximum individual risk,” MIR refers only to 

cancer risk. MIR, one metric for assessing cancer risk, is the 

estimated risk were an individual exposed to the maximum level of a 

pollutant for a lifetime.
Page 26 of 387 

In past residual risk determinations, EPA presented a 

number of human health risk metrics associated with emissions 

from the category under review, including: the MIR; the numbers 

of persons in various risk ranges; cancer incidence; the maximum 

non-cancer hazard index (HI); and the maximum acute non-cancer 

hazard. In estimating risks, EPA considered source categories 

under review that are located near each other and that affect 

the same population. EPA provided estimates of the expected 

difference in actual emissions from the source category under 

review and emissions allowed pursuant to the source category 

MACT standard. EPA also discussed and considered risk 

estimation uncertainties. EPA is providing this same type of 

information in support of these actions. 

 However, in contrast to past determinations, this notice 

presents and considers additional measures of health information 

to support our decision-making. These are discussed in more 

detail in later sections of this notice, and include: 

• Estimates of “total facility” cancer and non-cancer 

risk (risk from all HAP emissions from the facility at 

which the source category is located). 

• Demographic analyses (analyses of the distributions of 

HAP-related cancer risks and non-cancer risks, across 

different social, demographic, and economic groups 
Page 27 of 387 

within the populations living near the facilities 

where these source categories are located). 

• Additional estimates of the risks associated with 

emissions allowed by the MACT standard. 

The Agency is considering all of this available health 

information to inform our determinations of risk acceptability 

and ample margin of safety under CAA section 112(f). 

Specifically, as explained in the Benzene NESHAP, “[t]he 

Administrator believes that the acceptability of risk under 

section 112 is best judged on the basis of a broad set of health 

risk measures and information” and that “the first step judgment 

on acceptability cannot be reduced to any single factor.” 

Similarly, with regard to making the ample margin of safety 

determination, the Benzene NESHAP state that “[I]n the ample 

margin decision, the Agency again considers all of the health 

risk and other health information considered in the first step. 

Beyond that information, additional factors relating to the 

appropriate level of control will also be considered, including 

cost and economic impacts of controls, technological 

feasibility, uncertainties, and any other relevant factors.” 

The Agency acknowledges that the Benzene NESHAP provide 

flexibility regarding what factors the EPA might consider in 

making our determinations and how they might be weighed for each 

source category. In responding to comment on our policy under 
Page 28 of 387 

the Benzene NESHAP, EPA explained that: “The policy chosen by 

the Administrator permits consideration of multiple measures of 

health risk. Not only can the MIR figure be considered, but 

also incidence, the presence of non-cancer health effects, and 

the uncertainties of the risk estimates. In this way, the 

effect on the most exposed individuals can be reviewed as well 

as the impact on the general public. These factors can then be 

weighed in each individual case. This approach complies with 

the Vinyl Chloride mandate that the Administrator ascertain an 

acceptable level of risk to the public by employing [her] 

expertise to assess available data. It also complies with the 

Congressional intent behind the CAA, which did not exclude the 

use of any particular measure of public health risk from the 

EPA's consideration with respect to CAA section 112 regulations, 

and, thereby, implicitly permits consideration of any and all 

measures of health risk which the Administrator, in [her] 

judgment, believes are appropriate to determining what will 

‘protect the public health.’” 

For example, the level of the MIR is only one factor to be 

weighed in determining acceptability of risks. The Benzene 

NESHAP explain “an MIR of approximately 1-in-10 thousand should 

ordinarily be the upper end of the range of acceptability. As 

risks increase above this benchmark, they become presumptively 

less acceptable under CAA section 112, and would be weighed with 
Page 29 of 387 

the other health risk measures and information in making an 

overall judgment on acceptability. Or, the Agency may find, in 

a particular case, that a risk that includes MIR less than the 

presumptively acceptable level is unacceptable in the light of 

other health risk factors.” Similarly, with regard to the ample 

margin of safety analysis, the Benzene NESHAP state that: “...EPA 

believes the relative weight of the many factors that can be 

considered in selecting an ample margin of safety can only be 

determined for each specific source category. This occurs 

mainly because technological and economic factors (along with 

the health-related factors) vary from source category to source 

category.” 

EPA wishes to point out that certain health information has 

not been considered in these decisions. In assessing risks to 

populations in the vicinity of the facilities in each category, 

we present estimates of risk associated with HAP emissions from 

the source category alone (source category risk estimates) and 

HAP emissions from the entire facilities at which the covered 

source categories are located (facility-wide risk estimates). 

The Agency understands the potential importance of 

considering an individual’s total exposure to HAP in addition to 

considering exposure to HAP emissions from the source category 

and facility. This is particularly important when assessing 

non-cancer risks, where pollutant-specific exposure levels 
Page 30 of 387 

(e.g., Reference Concentration (RfC)) are based on the 

assumption that thresholds exist for adverse health effects. 

For example, the Agency recognizes that, although exposures 

attributable to emissions from a source category or facility 

alone may not indicate the potential for increased risk of 

adverse non-cancer health effects in a population, the exposures 

resulting from emissions from the facility in combination with 

emissions from all of the other sources (e.g., other facilities) 

to which an individual is exposed may be sufficient to result in 

increased risk of adverse non-cancer health effects. In May 

2010, the EPA Science Advisory Board (SAB) advised us “... that 

RTR assessments will be most useful to decision makers and 

communities if results are presented in the broader context of 

aggregate and cumulative risks, including background 

concentrations and contributions from other sources in the 

area.”3 

While we are interested in placing source category and 

facility-wide HAP risks in the context of total HAP risks from 

all sources combined in the vicinity of each source, we are 

 

3 EPA’s responses to this and all other key recommendations of the 

SAB’s advisory on RTR risk assessment methodologies (which is 

available at: 

http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F006

68381/$File/EPA-SAB-10-007-unsigned.pdf) are outlined in a memo to 

this rulemaking docket from David Guinnup entitled, EPA’s Actions in 

Response to the Key Recommnedations of the SAB Review of RTR Risk 

Assessment Methodologies. 

 
Page 31 of 387 

concerned about the uncertainties of doing so. At this point, 

we believe that such estimates of total HAP risks will have 

significantly greater associated uncertainties than for the 

source category or facility-wide estimates, hence, compounding 

the uncertainty in any such comparison. This is because we have 

not conducted a detailed technical review of HAP emissions data 

for source categories and facilities that have not previously 

undergone an RTR review or are not currently undergoing such 

review. We are requesting comment on whether and how best to 

estimate and evaluate total HAP exposure in our assessments, 

and, in particular, on whether and how it might be appropriate 

to use information from EPA’s National Air Toxics Assessment 

(NATA) to support such estimates. We are also seeking comment 

on how best to consider various types and scales of risk 

estimates when making our acceptability and ample margin of 

safety determinations under CAA section 112(f). Additionally, 

we are seeking recommendations for any other comparative 

measures that may be useful in the assessment of the 

distribution of HAP risks across potentially affected 

demographic groups. 

C. What other actions are we addressing in this proposal?

 In this proposal, we are addressing three additional types 

of action for some or all of these six MACT standards. For 

eight source categories subject to three of the MACT standards, 
Page 32 of 387 

we identified significant emission sources within the categories 

for which standards were not previously developed. We are 

proposing MACT standards for these emission sources pursuant to 

CAA section 112(d)(2) and (3). For four source categories 

subject to two of the MACT standards, we are also proposing 

changes to correct editorial errors, to make clarifications, and 

to address issues with implementation or determining compliance. 

We are also proposing to revise requirements in each of the six 

MACT standards related to emissions during periods of startup, 

shutdown, and malfunction (SSM). 

 The United States Court of Appeals for the District of 

Columbia Circuit vacated portions of two provisions in EPA’s CAA 

section 112 regulations governing the emissions of HAP during 

periods of SSM. Sierra Club v. EPA, 551 F.3d 1019 (District of 

Columbia Circuit, 2008), cert. denied, 130 S. Ct. 1735 (U.S. 

2010). Specifically, the Court vacated the SSM exemption 

contained in 40 CFR 63.6(f)(1) and (h)(1), that is part of a 

regulation, commonly referred to as the “General Provisions 

Rule,” that EPA promulgated under section 112 of the CAA. When 

incorporated into a CAA section 112(d) standard for a specific 

source category, these two provisions exempt sources within that 

source category from the requirement to comply with the 

otherwise applicable emission standard during periods of SSM. 

We are proposing to eliminate the SSM exemption in each of the 
Page 33 of 387 

six MACT standards addressed in this proposal. Consistent with 

Sierra Club v. EPA, we are proposing that the established 

standards in these rules apply at all times. We are also 

proposing to revise the General Provisions table in each of the 

six MACT standards in several respects. For example, we are 

removing the General Provisions’ requirement that the source 

develop an SSM plan. We are also removing certain recordkeeping 

and reporting requirements related to the SSM exemption, but we 

are retaining the recordkeeping and related requirements for 

malfunctions and request public comment on the requirements. 

EPA has attempted to ensure that regulatory language relating to 

the SSM exemption has been removed. We solicit comment on 

whether we have overlooked any regulatory provisions that might 

be inappropriate, unnecessary, or redundant based on our 

proposal to remove the exemption from compliance with the 

emission limit during periods of SSM. 

In the individual source category-specific discussions in 

section V of this preamble, we explain the specific changes we 

are proposing to make related to whether and how the applicable 

emission standards apply during startup and shutdown. Periods 

of startup, normal operations, and shutdown are all predictable 

and routine aspects of a source’s operations. In contrast, 

malfunction is defined as a “sudden, infrequent, and not 

reasonably preventable failure of air pollution control and 
Page 34 of 387 

monitoring equipment, process equipment or a process to operate 

in a normal or usual manner * * * ” (40 CFR 63.2). EPA believes 

that a malfunction should not be viewed as a distinct operating 

mode, and, therefore, any emissions that occur during 

malfunctions do not need to be factored into development of CAA 

section 112(d) standards, which, once promulgated, apply at all 

times. In Mossville Environmental Action Now v. EPA, 370 F.3d 

1232, 1242 (District of Columbia Circuit 2004), the Court upheld 

as reasonable standards that had factored in variability of 

emissions under all operating conditions. However, nothing in 

CAA section 112(d) or in case law requires that EPA anticipate 

and account for the innumerable types of potential malfunction 

events in setting emission standards. See, Weyerhaeuser v 

Costle, 590 F.2d 1011, 1058 (District of Columbia Circuit 1978) 

(“In the nature of things, no general limit, individual permit, 

or even any upset provision can anticipate all upset situations. 

After a certain point, the transgression of regulatory limits 

caused by "uncontrollable acts of third parties," such as 

strikes, sabotage, operator intoxication, or insanity, and a 

variety of other eventualities, must be a matter for the 

administrative exercise of case-by-case enforcement discretion, 

not for specification in advance by regulation.”) Further, it 

is reasonable to interpret CAA section 112(d) as not requiring 

EPA to account for malfunctions in setting emissions standards. 
Page 35 of 387 

For example, we note that CAA section 112 uses the concept of 

“best performing” sources in defining MACT, the level of 

stringency that major source standards must meet. Applying the 

concept of “best performing” to a source that is malfunctioning 

presents significant difficulties. The goal of best performing 

sources is to operate in such a way as to avoid malfunctions of 

their units. 

Moreover, even if malfunctions were considered a distinct 

operating mode, we believe it would be impracticable to take 

malfunctions into account in setting CAA section 112(d) 

standards. As noted above, by definition, malfunctions are 

sudden and unexpected events, and it would be difficult to set a 

standard that takes into account the myriad different types of 

malfunctions that can occur across all sources in each source 

category. Malfunctions can also vary in frequency, degree, and 

duration, further complicating standard setting. 

Under this proposal, in the event that a source fails to 

comply with the applicable CAA section 112(d) standards as a 

result of a malfunction event, EPA would determine an 

appropriate response based on, among other things, the good 

faith efforts of the source to minimize emissions during 

malfunction periods, including preventative and corrective 

actions, as well as root cause analyses to ascertain and rectify 

excess emissions. EPA would also consider whether the source's 
Page 36 of 387 

failure to comply with the CAA section 112(d) standard was, in 

fact, “sudden, infrequent, not reasonably preventable” and was 

not instead “caused in part by poor maintenance or careless 

operation.” 40 CRF 63.2 (definition of malfunction). 

Finally, EPA recognizes that, even equipment that is 

properly designed and maintained can sometimes fail, and that 

such failure can sometimes cause or contribute to an exceedance 

of the relevant emission standard. (See, e.g., State 

Implementation Plans: Policy Regarding Excessive Emissions 

During Malfunctions, Startup, and Shutdown (September 20, 1999); 

Policy on Excess Emissions During Startup, Shutdown, 

Maintenance, and Malfunctions (February 15, 1983)). Therefore, 

consistent with our recently promulgated final amendments to 

regulations addressing the Portland Cement category (75 FR 

54970, September 9, 2010), we are proposing to add regulatory 

language providing an affirmative defense against civil 

penalties for exceedances of emission limits that are caused by 

malfunctions in each of the six MACT standards addressed in this 

proposal. We are proposing to define “affirmative defense” to 

mean, in the context of an enforcement proceeding, a response or 

defense put forward by a defendant, regarding which the 

defendant has the burden of proof, and the merits of which are 

independently and objectively evaluated in a judicial or 

administrative proceeding). We are also proposing regulatory 
Page 37 of 387 

provisions to specify the elements that are necessary to 

establish this affirmative defense. (See 40 CFR 22.24). The 

proposed criteria would ensure that the affirmative defense is 

available only where the event that causes an exceedance of the 

emission limit meets the narrow definition of malfunction in 40 

CFR 63.2 (sudden, infrequent, not reasonably preventable, and 

not caused by poor maintenance and/or careless operation). The 

proposed criteria also are designed to ensure that steps are 

taken to correct the malfunction, to minimize emissions, and to 

prevent future malfunctions. In any judicial or administrative 

proceeding, the Administrator would be able to challenge the 

assertion of the affirmative defense and, if the respondent has 

not met its burden of proving all of the requirements in the 

affirmative defense, appropriate penalties could be assessed in 

accordance with section 113 of the CAA (see also 40 CFR 22.77). 

D. What specific RTR actions have previously been taken for 

these source categories?

For some of the 16 source categories covered by these six 

MACT standards, we have previously taken certain actions under 

the RTR program. Following is a summary of these previous 

actions and also a summary of additional reviews we have 

subsequently conducted for each source category. 

1. Categories for Which RTR Decisions Have Been Finalized. 
Page 38 of 387 

There are nine source categories regulated under the Group 

I Polymers and Resins MACT standard. For four of these source 

categories (Butyl Rubber Production, Ethylene Propylene Rubber 

Production, Neoprene Production, and Polysulfide Rubber 

Production), we previously proposed and promulgated a decision 

not to revise the standards for purposes of the RTR provisions 

in CAA sections 112(d)(6) and (f)(2).4

 See 72 FR 70543, December 

12, 2007 (proposed rule), and 73 FR 76220, December 16, 2008 

(final rule). These four categories were determined to be “lowrisk,” as the maximum lifetime individual cancer risks were less 

than 1-in-1-million, and there were no other health concerns of 

significance. Therefore, we determined that conducting 

additional risk analyses for these categories was not warranted. 

We are not re-opening the RTR in this notice for these four 

source categories, and do not seek additional comments on that 

prior RTR. 

However, for three of these four Group I Polymers and 

Resins source categories (Butyl Rubber Production, Ethylene 

Propylene Rubber Production, and Neoprene Production), we have 

identified significant emission sources for which MACT standards 

were not previously developed. In this proposal, we are 

proposing MACT standards for these emission sources, and we are 

 

4

 There are no longer any operating facilities in the United States 

that produce polysulfide rubber, and we do not anticipate any will 

begin to operate in the future. 
Page 39 of 387 

also proposing that the residual risks after implementation of 

these new MACT standards will not change our previous finding 

that these source categories present low risks and that our 

obligation to review the residual risk under CAA section 112(f) 

has also been satisfied. 

2. Categories for Which RTR Decisions Have Been Proposed, but 

Not Promulgated. 

For eight source categories covered under four of the MACT 

standards addressed in this proposal, we previously performed an 

RTR review and proposed that no revisions of the MACT standards 

were necessary to address residual risk and that it was not 

necessary to revise the existing standards under CAA section 

112(d)(6). See 73 FR 60423, October 10, 2008. The MACT 

standards addressed in this proposal included Marine Tank Vessel 

Loading Operations (MTVLO), Printing and Publishing Industry, 

Pharmaceuticals Production, and five of the source categories 

covered under Group I Polymers and Resins (Epichlorohydrin 

Elastomers, HypalonTM Production, Nitrile Butadiene Rubber 

Production, Polybutadiene Rubber Production, and Styrene 

Butadiene Rubber and Latex Production).5

 Comments were received 

on that proposal, but no final action has been taken. This 

 

5

 The Mineral Wool Production source category was also addressed in 

that same October 2008 proposal. We are not proposing any additional 

action for that source category in this proposal, but will do so in a 

separate future action. We note that there are no longer any 

operating facilities in the United States that produce HypalonTM, and 

we do not anticipate that any will begin operation in the future. 
Page 40 of 387 

proposal presents additional analyses we have performed since 

the proposal, for each of these source categories with regard to 

the RTR. In addition, we are proposing revisions to the SSM 

provisions in the existing standards for these source 

categories, and, for several of the source categories, we are 

proposing MACT standards under CAA sections 112(d)(2) and (3) 

for emission points that were not previously regulated. 

3. Categories For Which RTR Decisions Have Not Been Proposed. 

 We have not previously proposed any RTR actions for the 

four source categories (Hard and Decorative Chromium 

Electroplating, Chromium Anodizing Tanks, and Steel Pickling--

HCl Process Facilities and Hydrochloric Acid Regeneration 

Plants) covered by the Chromium Electroplating and Steel 

Pickling MACT standards. Therefore, this is our initial 

proposed action for these two MACT standards to address the RTR 

requirement. In addition, we identified significant advances in 

the housekeeping requirements in the chromium source categories 

for which we are proposing MACT standards. We are also 

proposing revisions to the provisions addressing SSM to ensure 

they are consistent with the Court decision in Sierra Club v. 

EPA, 551 F.3d 1019, and we are proposing changes to correct 

editorial errors, make clarifications, or address issues with 

implementation or determining compliance. 

IV. Analyses Performed 
Page 41 of 387 

 As discussed above, in this notice, we are taking the 

following actions: (1) we are newly proposing action or 

supplementing our previous proposal to address the RTR 

requirements of CAA sections 112(d)(6) and (f)(2) for 16 source 

categories covered by six different MACT standards; (2) for 

eight of the source categories, we are proposing MACT standards 

for significant emission sources that are not currently subject 

to emission standards under the MACT standards; (3) we are 

proposing to revise the provisions in each of these six MACT 

standards to address SSM to ensure that the SSM provisions are 

consistent with the Court decision in Sierra Club v. EPA, 551 F. 

3d 1019; and (4) for two of the MACT standards, we are proposing 

amendments to correct editorial errors, to make clarifications, 

and to address issues with implementation or determining 

compliance. 

A. How did we estimate risk posed by the source categories?

 To support the proposed decision under the RTR for each 

source category, EPA conducted risk assessments that provided 

estimates of the MIR posed by the HAP emissions from each source 

in a category and by each source category, the distribution of 

cancer risks within the exposed populations, cancer incidence, 

HI for chronic exposures to HAP with non-cancer health effects, 

hazard quotients (HQ) for acute exposures to HAP with non-cancer 

health effects, and an evaluation of the potential for adverse 
Page 42 of 387 

environmental effects. The risk assessments consisted of seven 

primary steps, as discussed below. 

The docket for this rulemaking contains the following 

documents which provide more information on the risk assessment 

inputs and models, Draft Residual Risk Assessment for 9 Source 

Categories, Draft Residual Risk Assessment for Steel Pickling, 

and Draft Residual Risk Assessment for Chromium Electroplating, 

as well as the memoranda for the Printing and Publishing 

Industry, MTVLO, Epichlorohydrin Elastomers Production, 

Polybutadiene Rubber Production, Styrene Butadiene Rubber 

Production, Nitrile Butadiene Production, and Pharmaceuticals 

Production source categories. 

1. Establishing the Nature and Magnitude of Actual Emissions 

and Identifying the Emissions Release Characteristics. 

For the source categories included in the October 10, 2008, 

proposal, we compiled preliminary data sets using readilyavailable information, reviewed the data, and made changes where 

necessary, and shared these data with the public via an Advanced 

Notice of Proposed Rulemaking (ANPRM). 72 FR 29287, March 29, 

2007. The data sets were then updated based on comments 

received on the ANPRM and, in some cases, with additional 

information gathered by EPA. For the five Group I Polymers and 

Resins I Production source categories included in the October 

2008, proposal (Epichlorohydrin Elastomers Production, HypalonTM
Page 43 of 387 

Production, Nitrile Butadiene Rubber Production, Polybutadiene 

Rubber Production, and Styrene Butadiene Rubber and Latex 

Production), the preliminary data sets were based on information 

we collected directly from industry on emissions data and 

emissions release characteristics. For the MTVLO, 

Pharmaceuticals Production, and the Printing and Publishing 

Industry source categories, we created the preliminary data sets 

using data in the 2002 National Emissions Inventory (NEI) Final 

Inventory, Version 1 (made publicly available on February 26, 

2006), supplemented by data collected directly from industry 

when available. The NEI is a database that contains information 

about sources that emit criteria air pollutants and their 

precursors, and HAP. The database includes estimates of annual 

air pollutant emissions from point, nonpoint, and mobile sources 

in the 50 States, the District of Columbia, Puerto Rico, and the 

Virgin Islands. The EPA collects this information and releases 

an updated version of the NEI database every 3 years. 

In the March 29, 2007, ANPRM, we specifically requested 

comment on, and updates to, these preliminary data sets. We 

received comments on emissions data and emissions release 

characteristics data for facilities in these source categories. 

These comments were reviewed, considered, and the emissions 

information was adjusted where we concluded the comments 

supported such adjustment. After incorporation of changes to 
Page 44 of 387 

the data sets from this public data review process, data sets 

were created that were used to conduct the risk assessments and 

other analyses that formed the basis for the proposed actions 

included in the October 10, 2008, proposal. 

Since the proposal, we have continued to scrutinize the 

data sets for these source categories and to review additional 

data that has become available since the October 10, 2008, 

proposal. For the Printing and Publishing Industry source 

category, we became aware that some facilities had closed. We 

also reviewed the emissions data and had questions about the 

emissions of certain HAP. After contact with industry, it was 

determined that those emissions did not occur from those 

facilities. We updated the Printing and Publishing Industry 

data set to reflect these changes in operating facilities and 

emissions. For the MTVLO data set, we had concerns that several 

emission points in our existing data set were mislabeled, and, 

thus, we extracted more recent data from the NEI. For this 

source category, the data set is based on the 2005 NEI. For the 

Pharmaceuticals Production source category data set, no changes 

are necessary to the data set used for the proposal. For the 

Polymers and Resins I MACT standard source categories included 

in the October 10, 2008, proposal, updates have been made based 

on information received in response to an industry information 

collection survey. Documentation for industry contacts, 
Page 45 of 387 

surveys, and other information gathered to support these changes 

is available in the docket for this action. 

For the four source categories not included in the December 

10, 2008, proposal, we compiled preliminary data sets using the 

best available information, reviewed the data, and made changes 

where necessary. For the three Chromium Electroplating MACT 

standard source categories (Chromium Anodizing Tanks, Decorative 

Chromium Electroplating, and Hard Chromium Electroplating) and 

the Steel Pickling source category, we compiled the preliminary 

data sets using data in the 2005 NEI. Then, for the Steel 

Pickling source category, seven facilities were contacted to 

verify their emissions and emissions release characteristic 

data, and we updated the data set based on the information 

collected. This updated data set was used to conduct the risk 

assessments and other analyses that form the bases for the 

proposed actions. 

For the Chromium Electroplating source categories, a review 

of the 2005 NEI data indicated that not all chromium 

electroplating facilities were included in the data set. To 

develop an emissions inventory for the entire industry that 

could be used for modeling, an additional data set was developed 

based on facilities with known addresses – a total of 1,629 

facilities compared to 122 facilities in the NEI. Emissions for 

each type of plant were estimated based on the model plants 
Page 46 of 387 

developed for the original Chromium Electroplating MACT 

standard,6

 with hard chromium model plants having the highest 

emissions, followed by decorative chromium electroplating, and 

then chromium anodizing. If the type of electroplating 

performed at a specific plant was unknown, we assumed these 

facilities were hard chrome electroplating when we estimated 

emissions and risks for those facilities. Although we knew 

that, by doing so, we would be overestimating emissions of 

chromium, and, therefore, also of risk, we made this 

conservative assumption because we did not have complete 

information, and we chose to overestimate to preserve an ample 

margin of safety in the risk assessment upon which our risk 

modeling would be based. This analysis and a supplemental 

assessment are fully described in section V.A. 

2. Establishing the Relationship Between Actual Emissions and 

MACT-Allowable Emissions Levels. 

The available emissions data in the NEI and from other 

sources typically represent the mass of emissions actually 

emitted during the specified annual time period. These “actual” 

emission levels are often lower than the level of emissions that 

a facility might be allowed to emit and still comply with the 

MACT standard. The emissions level allowed to be emitted by the 

 

6

 See EPA-HQ-OAR-2010-0600, Model Plant Data Used to Estimate Risk from 

Chromium Electroplating Sources. 
Page 47 of 387 

MACT standard is referred to as the “MACT-allowable” emissions 

level. This represents the highest emission level that could be 

emitted by the facility without violating the MACT standard. 

We discussed the use of both MACT-allowable and actual 

emissions in the final Coke Oven Batteries residual risk rule 

(70 FR 19998–19999, April 15, 2005) and in the proposed and 

final Hazardous Organic NESHAP (HON) residual risk rules (71 FR 

34428, June 14, 2006, and 71 FR 76609, December 21, 2006, 

respectively). In those previous actions, we noted that 

assessing the risks at the MACT-allowable level is inherently 

reasonable since these risks reflect the maximum level sources 

could emit and still comply with national emission standards. 

But we also explained that it is reasonable to consider actual 

emissions, where such data are available, in both steps of the 

risk analysis, in accordance with the Benzene NESHAP. (54 FR 

38044, September 14, 1989.) It is reasonable to consider actual 

emissions because sources typically seek to perform better than 

required by emission standards to provide an operational cushion 

to accommodate the variability in manufacturing processes and 

control device performance. 

As described above, the actual emissions data were compiled 

based on the NEI, information gathered from facilities and 

States, and information received in response to the ANPRM for 

several of the source categories. To estimate emissions at the 
Page 48 of 387 

MACT-allowable level, we developed a ratio of MACT-allowable to 

actual emissions for each emissions source type in each source 

category, based on the level of control required by the MACT 

standard compared to the level of reported actual emissions and 

available information on the level of control achieved by the 

emissions controls in use. For example, if there was 

information to suggest several facilities in a source category 

were controlling storage tank emissions by 98 percent while the 

MACT standards required only 92-percent control, we would 

estimate that MACT-allowable emissions from these emission 

points could be as much as four times higher (8-percent 

allowable emissions compared with 2-percent actually emitted), 

and the ratio of MACT-allowable to actual would be 4:1 for this 

emission point type at the facilities in this source category. 

After developing these ratios for each emission point type in 

each source category, we next applied these ratios on a 

facility-by-facility basis to the maximum chronic risk values 

from the inhalation risk assessment to obtain facility-specific 

maximum risk values based on MACT-allowable emissions. 

3. Conducting Dispersion Modeling, Determining Inhalation 

Exposures, and Estimating Individual and Population Inhalation 

Risks. 

Both long-term and short-term inhalation exposure 

concentrations and health risks from each of the source 
Page 49 of 387 

categories addressed in this proposal were estimated using the 

Human Exposure Model (Community and Sector HEM–3 version 1.1.0). 

The HEM–3 performs three of the primary risk assessment 

activities listed above: (1) Conducting dispersion modeling to 

estimate the concentrations of HAP in ambient air, (2) 

estimating long-term and short-term inhalation exposures to 

individuals residing within 50 km of the modeled sources, and 

(3) estimating individual and population-level inhalation risks 

using the exposure estimates and quantitative dose-response 

information. 

The dispersion model used by HEM–3 is AERMOD, which is one 

of EPA’s preferred models for assessing pollutant concentrations 

from industrial facilities.7

 To perform the dispersion modeling 

and to develop the preliminary risk estimates, HEM–3 draws on 

three data libraries. The first is a library of meteorological 

data, which is used for dispersion calculations. This library 

includes 1 year of hourly surface and upper air observations for 

130 meteorological stations, selected to provide coverage of the 

United States and Puerto Rico. A second library of United 

States Census Bureau census block8

 internal point locations and 

populations provides the basis of human exposure calculations 

 

7

 U.S. EPA. Revision to the Guideline on Air Quality Models: Adoption 

of a Preferred General Purpose (Flat and Complex Terrain) Dispersion 

Model and Other Revisions (70 FR 68218, November 9, 2005). 8

 A census block is generally the smallest geographic area for which 

census statistics are tabulated. 
Page 50 of 387 

(Census, 2000). In addition, the census library includes the 

elevation and controlling hill height for each census block, 

which are also used in dispersion calculations. A third library 

of pollutant unit risk factors and other health benchmarks is 

used to estimate health risks. These risk factors and health 

benchmarks are the latest values recommended by EPA for HAP and 

other toxic air pollutants. These values are available at 

http://www.epa.gov/ttn/atw/toxsource/summary.html and are 

discussed in more detail later in this section. 

In developing the risk assessment for chronic exposures, we 

used the estimated annual average ambient air concentration of 

each of the HAP emitted by each source for which we have 

emissions data in the source category. The air concentrations 

at each nearby census block centroid were used as a surrogate 

for the chronic inhalation exposure concentration for all the 

people who reside in that census block. We calculated the MIR 

for each facility as the cancer risk associated with a lifetime 

(70-year period) of exposure to the maximum concentration at the 

centroid of an inhabited census block. Individual cancer risks 

were calculated as the lifetime exposure to the ambient 

concentration of each of the HAP multiplied by its Unit Risk 

Estimate (URE), which is an upper bound estimate of an 

individual’s probability of contracting cancer over a lifetime 

of exposure to a concentration of 1 microgram of the pollutant 
Page 51 of 387 

per cubic meter of air. For residual risk assessments, we 

generally use URE values from EPA’s Integrated Risk Information 

System (IRIS).9

 For carcinogenic pollutants without EPA IRIS 

values, we look to other reputable sources of cancer doseresponse values, often using California Environmental Protection 

Agency (CalEPA) URE values, where available. In cases where 

new, scientifically credible dose response values have been 

developed in a manner consistent with EPA guidelines and have 

undergone a peer review process similar to that used by EPA, we 

may use such dose-response values in place of, or in addition 

to, other values. Formaldehyde is a specific case in point. 

 In 2004, EPA determined that the Chemical Industry 

Institute of Toxicology (CIIT) dose response value for 

formaldehyde was based on better science than the IRIS dose 

response value, and we switched from using the IRIS value to the 

CIIT value in risk assessments supporting regulatory actions. 

This determination was based on a substantial body of research 

on the inhalation dosimetry for formaldehyde in rodents and 

primates by the CIIT Centers for Health Research (formerly the 

CIIT), with a focus on use of rodent data for refinement of the 

 

9

 The IRIS information is available at http://www.epa.gov/IRIS. 
Page 52 of 387 

quantitative cancer dose-response assessment.10,11,12 CIIT’s risk 

assessment of formaldehyde incorporated mechanistic and 

dosimetric information on formaldehyde. However, recent 

research published by EPA indicates that, when the CIIT’s twostage modeling assumptions are varied, resulting dose-response 

estimates can vary by several orders of magnitude.13,14,15,16 These 

findings are not supportive of interpreting the CIIT model 

results as providing a conservative (health-protective) estimate 

of human risk.17 The recent EPA research also examined the 

contribution of the two-stage modeling for formaldehyde towards 

 

10 Conolly, RB, Kimbell, JS, Janszen, D, Schlosser, PM, Kalisak, D, 

Preston, J, and Miller, FJ. 2003. Biologically Motivated 

Computational Modeling of Formaldehyde Carcinogenicity in the F344 

Rat. Tox Sci 75: 432-447. 11 Conolly, RB, Kimbell, JS, Janszen, D, Schlosser, PM, Kalisak, D, 

Preston, J, and Miller, FJ. 2004. Human Respiratory Tract Cancer 

Risks of Inhaled Formaldehyde: Dose-Response Predictions Derived from 

Biologically-Motivated Computational Modeling of a Combined Rodent and 

Human Dataset. Tox Sci 82: 279-296. 12 Chemical Industry Institute of Toxicology (CIIT). 1999. 

Formaldehyde: Hazard Characterization and Dose-Response Assessment 

for Carcinogenicity by the Route of Inhalation. CIIT, September 28, 

1999. Research Triangle Park, NC. 

13 U.S. EPA. Analysis of the Sensitivity and Uncertainty in 2-Stage 

Clonal Growth Models for Formaldehyde with Relevance to Other 

Biologically-Based Dose Response (BBDR) Models. U.S. EPA, Washington, 

D.C., EPA/600/R-08/103, 2008. 

14 Subramaniam, R; Chen, C; Crump, K; et al. (2008). Uncertainties in 

Biologically-Based Modeling of Formaldehyde-Induced Cancer Risk: 

Identification of Key Issues. Risk Anal 28(4):907-923. 15 Subramaniam, R; Chen, C; Crump, K; et al. (2007). Uncertainties in 

the CIIT 2-Stage Model for Formaldehyde-Induced Nasal Cancer in the 

F344 Rat: a Limited Sensitivity Analysis-I. Risk Anal 27:1237. 16 Crump, K; Chen, C; Fox, J; et al. (2008). Sensitivity Analysis of 

Biologically Motivated Model for Formaldehyde-induced respiratory 

cancer in humans. Ann Occup Hyg 52:481-495. 17 Crump, K; Chen, C; Fox, J; et al. (2008). Sensitivity Analysis of 

Biologically Motivated Model for Formaldehyde-Induced Respiratory 

Cancer in Humans. Ann Occup Hyg 52:481-495. 
Page 53 of 387 

characterizing the relative weights of key events in the modeof-action of a carcinogen. For example, the model-based 

inference in the published CIIT study that formaldehyde’s direct 

mutagenic action is not relevant to the compound’s 

tumorigenicity was found not to hold under variations of 

modeling assumptions.18 As a result of these findings, the CIIT 

URE value is no longer considered health protective, and we are 

again using the Agency’s current value on IRIS, which was last 

revised in 1991. We note that a new IRIS re-assessment has been 

drafted and sent to the National Academy of Sciences (NAS) for 

review. The NAS review is not expected to be final until 

sometime in 2011. 

We note here that several carcinogens have a mutagenic mode 

of action.19 For these compounds, the age-dependent adjustment 

factors described in EPA’s Supplemental Guidance for Assessing 

Susceptibility from Early-Life Exposure to Carcinogens20 were 

applied. This adjustment has the effect of increasing the 

estimated lifetime risks for these pollutants by a factor of 

 

18 Subramaniam, R; Chen, C; Crump, K; et al. (2007). Uncertainties in 

the CIIT 2-Stage Model for Formaldehyde-Induced Nasal Cancer in the 

F344 Rat: A Limited Sensitivity Analysis-I. Risk Anal 27:1237. 19 U.S. EPA, 2006. Performing risk assessments that include 

carcinogens described in the Supplemental Guidance as having a 

mutagenic mode of action. Science Policy Council Cancer Guidelines 

Implementation Workgroup Communication II: Memo from W.H. Farland 

dated June 14, 2006. 

http://epa.gov/osa/spc/pdfs/CGIWGCommunication_II.pdf. 20 U.S. EPA, 2005. Supplemental Guidance for Assessing Early-Life 

Exposure to Carcinogens. EPA/630/R-03/003F. 

http://www.epa.gov/ttn/atw/childrens_supplement_final.pdf. 
Page 54 of 387 

1.6.21 In addition, although only a small fraction of the total 

polycyclic organic matter (POM) emissions were reported as 

individual compounds, EPA expresses carcinogenic potency for 

compounds in this group in terms of benzo[a]pyrene equivalence, 

based on evidence that carcinogenic POM have the same mutagenic 

mechanism of action as does benzo[a]pyrene. For this reason, 

EPA’s Science Policy Council22 recommends applying the 

Supplemental Guidance to all carcinogenic polycyclic aromatic 

hydrocarbons for which risk estimates are based on relative 

potency. Accordingly, we have applied the Supplemental Guidance

to all unspeciated POM mixtures. 

 Incremental individual lifetime cancer risks associated 

with emissions from the source category were estimated as the 

sum of the risks for each of the carcinogenic HAP (including 

those classified as carcinogenic to humans, likely to be 

carcinogenic to humans, and suggestive evidence of carcinogenic 

 

21 Only one of these mutagenic compounds, benzo[a]pyrene, is emitted by any of 

the sources covered by this proposal. 

22 U.S. EPA, 2005. Science Policy Council Cancer Guidelines 

Implementation Workgroup Communication I: Memo from W.H. Farland 

dated October 4, 2005, to Science Policy Council. 

http://www.epa.gov/osa/spc/pdfs/canguid1.pdf. 
Page 55 of 387 

potential23) emitted by the modeled source. Cancer incidence and 

the distribution of individual cancer risks for the population 

within 50 km of any source were also estimated for the source 

category as part of these assessments by summing individual 

risks. A distance of 50 km is consistent with both the analysis 

supporting the 1989 Benzene NESHAP (54 FR 38044) and the 

limitations of Gaussian dispersion modeling. 

To assess risk of non-cancer health effects from chronic 

exposures, we summed the HQ for each of the HAP that affects a 

common target organ system to obtain the HI for that target 

organ system (or target organ-specific HI, TOSHI). The HQ is 

the estimated exposure divided by the chronic reference level, 

which is either the U.S. EPA RfC, defined as “an estimate (with 

uncertainty spanning perhaps an order of magnitude) of a 

continuous inhalation exposure to the human population 

(including sensitive subgroups) that is likely to be without an 

appreciable risk of deleterious effects during a lifetime,” or, 

in cases where an RfC is not available, the CalEPA Chronic 

 

23 These classifications also coincide with the terms "known 

carcinogen, probable carcinogen, and possible carcinogen," 

respectively, which are the terms advocated in the EPA's previous 

Guidelines for Carcinogen Risk Assessment, published in 1986 (51 FR 

33992, September 24, 1986). Summing the risks of these individual 

compounds to obtain the cumulative cancer risks is an approach that 

was recommended by the EPA's SAB in their 2002 peer review of EPA's 

NATA entitled, NATA - Evaluating the National-scale Air Toxics 

Assessment 1996 Data -- an SAB Advisory, available at: 

http://yosemite.epa.gov/sab/sabproduct.nsf/214C6E915BB04E14852570CA007

A682C/$File/ecadv02001.pdf.
Page 56 of 387 

Reference Exposure Level (REL), defined as “the concentration 

level at or below which no adverse health effects are 

anticipated for a specified exposure duration.” As noted above, 

in cases where new, scientifically credible dose-response values 

have been developed in a manner consistent with EPA guidelines 

and have undergone a peer review process similar to that used by 

EPA, we may use those dose-response values in place of, or in 

addition to, other values. 

Screening estimates of acute exposures and risks were also 

evaluated for each of the HAP at the point of highest off-site 

exposure for each facility (i.e., not just the census block 

centroids) assuming that a person is located at this spot at a 

time when both the peak (hourly) emission rate and hourly 

dispersion conditions (1991 calendar year data) occur. In each 

case, acute HQ values were calculated using best available, 

short-term health threshold values. These acute threshold 

values include REL, Acute Exposure Guideline Levels (AEGL), and 

Emergency Response Planning Guidelines (ERPG) for 1-hour 

exposure durations. As discussed below, we used conservative 

assumptions for emission rates, meteorology, and exposure 

location for our acute analysis. 

As described in the CalEPA’s Air Toxics Hot Spots Program 

Risk Assessment Guidelines, Part I, The Determination of Acute 

Reference Exposure Levels for Airborne Toxicants, an acute REL 
Page 57 of 387 

value (http://www.oehha.ca.gov/air/pdf/acuterel.pdf) is defined 

as “the concentration level at or below which no adverse health 

effects are anticipated for a specified exposure duration is 

termed the REL. REL values are based on the most sensitive, 

relevant, adverse health effect reported in the medical and 

toxicological literature. REL values are designed to protect 

the most sensitive individuals in the population by the 

inclusion of margins of safety. Since margins of safety are 

incorporated to address data gaps and uncertainties, exceeding 

the REL value does not automatically indicate an adverse health 

impact.” 

AEGL values were derived in response to recommendations 

from the National Research Council (NRC). As described in 

“Standing Operating Procedures (SOP) of the National Advisory 

Committee on Acute Exposure Guideline Levels for Hazardous 

Substances” (http://www.epa.gov/opptintr/aegl/pubs/sop.pdf),24

“the NRC’s previous name for acute exposure levels—community 

emergency exposure levels (CEEL)— was replaced by the term AEGL 

to reflect the broad application of these values to planning, 

response, and prevention in the community, the workplace, 

transportation, the military, and the remediation of Superfund 

sites.” This document also states that AEGL values “represent 

 

24 NAS, 2001. Standing Operating Procedures for Developing Acute 

Exposure Levels for Hazardous Chemicals, page 2. 
Page 58 of 387 

threshold exposure limits for the general public and are 

applicable to emergency exposures ranging from 10 minutes to 8 

hours.” The document lays out the purpose and objectives of 

AEGL by stating (page 21) that “the primary purpose of the AEGL 

program and the NAC/AEGL Committee is to develop guideline 

levels for once-in-a-lifetime, short-term exposures to airborne 

concentrations of acutely toxic, high-priority chemicals.” In 

detailing the intended application of AEGL values, the document 

states (page 31) that ”[i]t is anticipated that the AEGL values 

will be used for regulatory and nonregulatory purposes by United 

States Federal and State agencies, and possibly the 

international community in conjunction with chemical emergency 

response, planning, and prevention programs. More specifically, 

the AEGL values will be used for conducting various risk 

assessments to aid in the development of emergency preparedness 

and prevention plans, as well as real-time emergency response 

actions, for accidental chemical releases at fixed facilities 

and from transport carriers.” 

The AEGL–1 value is then specifically defined as “the 

airborne concentration of a substance above which it is 

predicted that the general population, including susceptible 

individuals, could experience notable discomfort, irritation, or 

certain asymptomatic nonsensory effects. However, the effects 

are not disabling and are transient and reversible upon 
Page 59 of 387 

cessation of exposure.” The document also notes (page 3) that, 

“Airborne concentrations below AEGL–1 represent exposure levels 

that can produce mild and progressively increasing but transient 

and nondisabling odor, taste, and sensory irritation or certain 

asymptomatic, nonsensory effects.” Similarly, the document 

defines AEGL–2 values as “the airborne concentration (expressed 

as ppm or mg/m3

) of a substance above which it is predicted that 

the general population, including susceptible individuals, could 

experience irreversible or other serious, long-lasting adverse 

health effects or an impaired ability to escape.” 

ERPG values are derived for use in emergency response, as 

described in the American Industrial Hygiene Association’s 

document entitled, Emergency Response Planning Guidelines (ERPG) 

Procedures and Responsibilities

(http://www.aiha.org/1documents/committees/ERPSOPs2006.pdf), 

which states that, “Emergency Response Planning Guidelines were 

developed for emergency planning and are intended as healthbased guideline concentrations for single exposures to 

chemicals.”25 The ERPG–1 value is defined as “the maximum 

airborne concentration below which it is believed that nearly 

all individuals could be exposed for up to 1 hour without 

experiencing other than mild transient adverse health effects or 

 

25 ERP Committee Procedures and Responsibilities. 1 November 2006. 

American Industrial Hygiene Association. 
Page 60 of 387 

without perceiving a clearly defined, objectionable odor.” 

Similarly, the ERPG–2 value is defined as “the maximum airborne 

concentration below which it is believed that nearly all 

individuals could be exposed for up to 1 hour without 

experiencing or developing irreversible or other serious health 

effects or symptoms which could impair an individual’s ability 

to take protective action.” 

As can be seen from the definitions above, the AEGL and 

ERPG values include the similarly-defined severity levels 1 and 

2. For many chemicals, a severity level 1 value AEGL or ERPG 

has not been developed; in these instances, higher severity 

level AEGL–2 or ERPG–2 values are compared to our modeled 

exposure levels to screen for potential acute concerns. 

Acute REL values for 1-hour exposure durations are 

typically lower than their corresponding AEGL–1 and ERPG–1 

values. Even though their definitions are slightly different, 

AEGL–1 values are often the same as the corresponding ERPG–1 

values, and AEGL–2 values are often equal to ERPG–2 values. 

Maximum HQ values from our acute screening risk assessments 

typically result when basing them on the acute REL value for a 

particular pollutant. In cases where our maximum acute HQ value 

exceeds 1, we also report the HQ value based on the next highest 

acute threshold (usually the AEGL–1 and/or the ERPG–1 value). 
Page 61 of 387 

To develop screening estimates of acute exposures, we 

developed estimates of maximum hourly emission rates by 

multiplying the average actual annual hourly emission rates by a 

factor to cover routinely variable emissions. We chose the 

factor to use based on process knowledge and engineering 

judgment and with awareness of a Texas study of short-term 

emissions variability, which showed that most peak emission 

events, in a heavily-industrialized 4-county area (Harris, 

Galveston, Chambers, and Brazoria Counties, Texas), were less 

than twice the annual average hourly emission rate, and the 

highest peak emission event was 8.5 times the annual average 

hourly emission rate.26 This analysis is provided in Appendix 4 

of the Draft Residual Risk Assessment for Source Categories 

Report and is available in the docket for this action. 

Considering this analysis, unless specific process knowledge 

provided an alternate value, a conservative screening 

multiplication factor of 10 was applied to the average annual 

hourly emission rate in these acute exposure screening 

assessments. 

In cases where all acute HQ values from the screening step 

were less than or equal to 1, acute impacts were deemed 

negligible and no further analysis was performed. In the cases 

 

26 See http://www.tceq.state.tx.us/compliance/field_ops/eer/index.html

or docket to access the source of these data. 
Page 62 of 387 

where an acute HQ from the screening step was greater than 1, 

additional site-specific data were considered to develop a more 

refined estimate of the potential for acute impacts of concern. 

The data refinements considered included using a peak-to-mean 

hourly emissions ratio based on source category-specific 

knowledge or data (rather than the default factor of 10) and 

using the site-specific facility layout to distinguish facility 

property from an area where the public could be exposed. 

Ideally, we would prefer to have continuous measurements over 

time to see how the emissions vary by each hour over an entire 

year. Having a frequency distribution of hourly emission rates 

over a year would allow us to perform a probabilistic analysis 

to estimate potential threshold exceedances and their frequency 

of occurrence. Such an evaluation could include a more complete 

statistical treatment of the key parameters and elements adopted 

in this screening analysis. However, we recognize that having 

this level of data is rare, hence our use of the multiplier 

approach. 

4. Conducting Multipathway Exposure and Risk Modeling. 

The potential for significant human health risks due to 

exposures via routes other than inhalation (i.e., multipathway 

exposures) and the potential for adverse environmental impacts 

were evaluated in a three-step process. In the first step, we 

determined whether any facilities emitted any HAP known to be 
Page 63 of 387 

persistent and bio-accumulative in the environment (PB-HAP). 

There are 14 PB-HAP compounds or compound classes identified for 

this screening in EPA’s Air Toxics Risk Assessment Library 

(available at http://www.epa.gov/ttn/fera/risk_atra_vol1.html). 

They are cadmium compounds, chlordane, chlorinated 

dibenzodioxins and furans, dichlorodiphenyldichloroethylene, 

heptachlor, hexachlorobenzene, hexachlorocyclohexane, lead 

compounds, mercury compounds, methoxychlor, polychlorinated 

biphenyls, POM, toxaphene, and trifluralin. 

In the second step of the screening process, we determined 

whether the facility-specific emission rates of each of the 

emitted PB–HAP were large enough to create the potential for 

significant non-inhalation risks. To facilitate this step, we 

have developed emission rate thresholds for each PB–HAP using a 

hypothetical screening exposure scenario developed for use in 

conjunction with the TRIM.FaTE model. The hypothetical 

screening scenario was subjected to a sensitivity analysis to 

ensure that its key design parameters were established such that 

environmental media concentrations were not underestimated 

(i.e., to minimize the occurrence of false negatives, or results 

that suggest that risks might be acceptable when, in fact, 

actual risks are high), and to also minimize the occurrence of 

false positives for human health endpoints. We call this 

application of the TRIM.FaTE model TRIM-Screen. The facility-
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specific emission rates of each of the PB–HAP in each source 

category were compared to the emission threshold values for each 

of the PB–HAP identified in the source category data sets. 

For all of the facilities in the source categories 

addressed in this proposal, all of the PB-HAP emission rates 

were less than the emission threshold values. As a result of 

this, multi-pathway exposures and environmental risks were 

deemed negligible and no further analysis was performed. If the 

emission rates of the PB-HAP had been above the emission 

threshold values, the source categories would have been further 

evaluated for potential non-inhalation risks and adverse 

environmental effects in a third step through site-specific 

refined assessments using EPA’s TRIM.FaTE model. 

For further information on the multi-pathway analysis 

approach, see the residual risk documentation as referenced in 

section IV.A of this preamble. 

5. Assessing Risks Considering Emissions Control Options. 

 In addition to assessing baseline inhalation risks and 

screening for potential multi-pathway risks, for some source 

categories, where appropriate, we also estimated risks 

considering the potential emission reductions that would be 

achieved by the particular control options under consideration. 

The inhalation and multi-pathway risks estimated, as described 

above, at the actual and MACT-allowable levels represent the 
Page 65 of 387 

actual and maximum allowable operating conditions of the 

facilities in the source categories analyzed. For source 

categories where emission reduction options were available, we 

estimated risk based on the expected emissions reductions that 

would be realized with those additional emissions controls. In 

these cases, the expected emissions reductions were applied to 

the specific HAP and emissions sources in the source category 

data set. The results of the risk analyses considering the 

application of emissions controls are included in the residual 

risk documentation as referenced in section IV.A of this 

preamble, which is available in the docket for this action. 

6. Conducting Other Risk-Related Analyses, Including FacilityWide Assessments and Demographic Analyses. 

a. Facility-Wide Risk. 

To put the source category risks in context, we also 

examined the risks from the entire “facility,” where the 

facility includes all HAP-emitting operations within a 

contiguous area and under common control. In other words, for 

each facility that includes one or more sources from one of the 

source categories under review, we examined the HAP emissions 

not only from the source category of interest, but also 

emissions of from all other emission sources at the facility. 

The data for these “facility-wide” risks were obtained from the 

draft 2005 NATA, which is a nationwide screening-level 
Page 66 of 387 

assessment based on the NEI (available at 

http://www.epa.gov/ttn/atw/natamain/index.html). We analyzed 

risks due to the inhalation of HAP that are emitted “facilitywide” for the populations residing within 50 km of each 

facility, consistent with the source category analysis described 

above. For these facility-wide risk analyses, the modeled 

source category risks were compared to the facility-wide risks 

to determine the portion of facility-wide risks that could be 

attributed to each of the six source categories being addressed 

in this proposal, we specifically examined the facility that was 

associated with the highest estimate of risk and determined the 

percentage of that risk attributable to the source category of 

interest. The risk documentation available through the docket 

for this action provides all the facility-wide risks and the 

percentage of source category contribution for all source 

categories assessed. 

The methodology and the results of the facility-wide 

analyses for each source category are included in the residual 

risk documentation as referenced in section IV.A of this 

preamble, which is available in the docket for this action. 

b. Demographic Analysis.

To examine the potential for any environmental justice 

issues that might be associated with each source category, we 

evaluated the distributions of HAP-related cancer and non-cancer 
Page 67 of 387 

risks across different social, demographic, and economic groups 

within the populations living near the facilities where these 

source categories are located. The development of demographic 

analyses to inform the consideration of environmental justice 

issues in EPA rulemakings is an evolving science. The EPA 

offers the demographic analyses in this rulemaking as examples 

of how such analyses might be developed to inform such 

consideration, and invites public comment on the approaches used 

and the interpretations made from the results, with the hope 

that this will support the refinement and improve utility of 

such analyses for future rulemakings. 

For this analysis, we analyzed risks due to the inhalation 

of HAP in two separate ways. In the first approach, we focus 

the analysis on the total populations residing within 5 km of 

each facility (source category and facility-wide), regardless of 

their estimated risks, and examine the distributions of 

estimated risk across the various demographic groups within 

those 5 km circles. The distance of 5 km was chosen for the 

first approach to be consistent with previous demographic 

analyses performed at EPA, such as the one which was performed 

in support of the recent proposal for the Boilers NESHAP. In 

the second approach, we focus the analysis only on the 
Page 68 of 387 

populations within 5 km27 of any facility estimated to have 

exposures to HAP which result in cancer risks of 1-in-1 million 

or greater or non-cancer hazard indices of 1 or greater (based 

on the emissions of the source category or the facility, 

respectively). Once again, we examine the distributions of 

those risks across various demographic groups. In each 

approach, we compare the percentages of particular demographic 

groups to the total number of people in those demographic groups 

nationwide. In this preamble, we only present the results of 

the second approach since it focuses on the significant risks 

from either the source category or the facility-wide emissions. 

The results of both approaches including other risk metrics such 

as average risks for the exposed populations are documented in 

source category-specific technical reports in the docket for 

each of the source categories covered in this proposal.28

The basis for the risk values used in these analyses were 

the modeling results obtained from the HEM-3 model described 

above. The risk values for each census block were linked to a 

database of information from the 2000 Decennial census that 

 

27 Generally, we have found that using a 5 km radius in the analysis 

will capture more than 90 percent of all the individuals with cancer 

risks above 1-in-1 million. In the future, we plan to extend these 

analyses to cover the entire modeled domain for a facility (50 km 

radius) to capture all individuals with risks above 1-in-1 million 

from the affected facilities. 

28 For example, the report pertaining to the Hard Chromium 

Electroplating source category is entitled Risk and Technology Review 

– Analysis of Socio-Economic Factors for Populations Living Near Hard 

Chromium Electroplating Facilities. 
Page 69 of 387 

includes data on race and ethnicity, age distributions, poverty 

status, household incomes, and education level. The Census 

Department Landview®

 database was the source of the data on race 

and ethnicity, and the data on age distributions, poverty 

status, household incomes, and education level was obtained from 

the 2000 Census of Population and Housing Summary File 3 (SF3) 

Long Form. While race and ethnicity census data are available 

at the block group level, the age and income census data are 

only available at the census block level (which includes an 

average of 26 blocks or an average of 1,350 people). Where 

census data are available at the block group level but not the 

block level, we assumed that all blocks within the block group 

have the same distribution of ages and incomes as the block 

group. 

For each source category, the analysis results include the 

distribution of estimated lifetime inhalation cancer and chronic 

non-cancer risks for different racial and ethnic groups, 

different age groups, adults with and without a high school 

diploma, people living in households below the national median 

income, and for people living below the poverty line among the 

population living near these facilities. The specific census 

population categories studied include: 

• Total population 

• White 
Page 70 of 387 

• African American (or Black) 

• Native Americans 

• Other races and multiracial 

• Hispanic or Latino 

• Children 18 years of age and under 

• Adults 19 to 64 years of age 

• Adults 65 years of age and over 

• Adults without a high school diploma 

• Households earning under the national median income 

• People living below the poverty line 

It should be noted that these categories overlap in some 

instances, resulting in some populations being counted in more 

than one category (e.g., other races and multiracial and 

Hispanic). In addition, while not a specific census population 

category, we also examined risks to the category “Minorities,” 

which is defined as all race population categories except white. 

Since these demographic analysis methods are still evolving, EPA 

specifically solicits comment on the inclusion of other 

demographic categories (e.g., “Hispanic and Non-white”) in our 

future analyses. 

For further information about risks to the populations 

local to the facilities in these source categories, we also 

evaluated the estimated distribution of inhalation cancer and 

chronic non-cancer risks associated with the HAP emissions from 
Page 71 of 387 

all the emissions sources at the facility (i.e., facility-wide). 

This analysis used the facility-wide RTR modeling results and 

the census data described above. 

The methodology and the results of the demographic analyses 

for each source category are included in the residual risk 

documentation as referenced in section IV.A of this preamble, 

which is available in the docket for this action. 

7. Considering Uncertainties in Risk Assessment.

Uncertainty and the potential for bias are inherent in all 

risk assessments, including those performed for the source 

categories addressed in this proposal. Although uncertainty 

exists, we believe the approach that we took, which used 

conservative tools and assumptions, ensures that our decisions 

are health-protective. A brief discussion of the uncertainties 

in the emissions data sets, dispersion modeling, inhalation 

exposure estimates, and dose-response relationships follows 

below. A more thorough discussion of these uncertainties is 

included in the Draft Residual Risk Assessment for the Steel 

Pickling Source Category (July 2010), Draft Residual Risk 

Assessment for the Chromium Electroplating Source Category (July 

2010), Draft Residual Risk Assessment for 9 Source Categories

(August 2008), and the Risk and Technology Review (RTR) 

Assessment Plan (November 2006), each of which are available in 

the docket for this action. 
Page 72 of 387 

a. Uncertainties in the Emissions Data Sets. 

Although the development of the RTR data sets involved 

quality assurance/quality control processes, the accuracy of 

emissions values will vary depending on the source of the data, 

the degree to which data is incomplete or missing, the degree to 

which assumptions made to complete the data sets are inaccurate, 

errors in estimating emissions values, and other factors. The 

emission values considered in this analysis generally are annual 

totals that do not reflect short-term fluctuations during the 

course of a year or variations from year to year. In contrast, 

the estimates of peak hourly emission rates for the acute 

effects screening assessment were based on multiplication 

factors applied to the average annual hourly emission rates (the 

default factor is 10), which are intended to account for 

emission fluctuations due to normal facility operations. In 

some cases, more refined estimates were used for source 

categories where the screening estimates did not “screen out” 

all sources and more specific information was available. 

Additionally, for some source categories our estimate of the 

number of facilities may not represent the number of facilities 

that we have in our notice of proposed rulemaking data set. 

There is also significant uncertainty for some source categories 

in the identification of sources as major or area in the NEI. 

b. Uncertainties in Dispersion Modeling. 
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While the analysis employed EPA’s recommended regulatory 

dispersion model, AERMOD, we recognize that there is uncertainty 

in ambient concentration estimates associated with any model, 

including AERMOD. Where possible, model options (e.g., 

rural/urban, plume depletion, chemistry) were selected to 

provide an overestimate of ambient air concentrations of the 

HAP. However, because of practicality and data limitation 

reasons, some factors (e.g., meteorology, building downwash) 

have the potential in some situations to overestimate or 

underestimate ambient impacts. For example, meteorological data 

were taken from a single year (1991), and facility locations can 

be a significant distance from the site where these data were 

taken. Despite these uncertainties, we believe that at off-site 

locations and census block centroids, the approach considered in 

the dispersion modeling analysis should generally yield 

overestimates of ambient HAP concentrations. 

c. Uncertainties in Inhalation Exposure. 

The effects of human mobility on exposures were not 

included in the assessment. Specifically, short-term mobility 

and long-term mobility between census blocks in the modeling 

domain were not considered.29 As a result, this simplification 

will likely bias the assessment toward overestimating the 

 

29 Short-term mobility is movement from one microenvironment to another 

over the course of hours or days. Long-term mobility is movement from 

one residence to another over the course of a lifetime. 
Page 74 of 387 

highest exposures. In addition, the assessment predicted the 

chronic exposures at the centroid of each populated census block 

as surrogates for the exposure concentrations for all people 

living in that block. Using the census block centroid to 

predict chronic exposures tends to over-predict exposures for 

people in the census block who live further from the facility 

and under-predict exposures for people in the census block who 

live closer to the facility. Thus, using the census block 

centroid to predict chronic exposures may lead to a potential 

understatement or overstatement of the true maximum impact, but 

is an unbiased estimate of average risk and incidence. 

The assessments evaluate the cancer inhalation risks 

associated with pollutant exposures over a 70-year period, which 

is the assumed lifetime of an individual. In reality, both the 

length of time that modeled emissions sources at facilities 

actually operate (i.e., more or less than 70 years), and the 

domestic growth or decline of the modeled industry (i.e., the 

increase or decrease in the number or size of United States 

facilities), will influence the risks posed by a given source 

category. Depending on the characteristics of the industry, 

these factors will likely result in an overestimate (or possibly 

an underestimate in the extreme case where a facility maintains 

or increases its emission levels beyond 70 years and residents 

live beyond 70 years at the same location) both in individual 
Page 75 of 387 

risk levels and in the total estimated number of cancer cases. 

Annual cancer incidence estimates from exposures to emissions 

from these sources would not be affected by uncertainty in the 

length of time emissions sources operate. 

The exposure estimates used in these analyses assume 

chronic exposures to ambient levels of pollutants. Because most 

people spend the majority of their time indoors, actual 

exposures may not be as high, depending on the characteristics 

of the pollutants modeled. For many HAP, indoor levels are 

roughly equivalent to ambient levels, but for very reactive 

pollutants or larger particles, these levels are typically 

lower. This factor has the potential to result in an 

overstatement of 25 to 30 percent of exposures.30 

In addition to the uncertainties highlighted above, there 

are several factors specific to the acute exposure assessment 

that should be highlighted. The accuracy of an acute inhalation 

exposure assessment depends on the simultaneous occurrence of 

independent factors that may vary greatly, such as hourly 

emissions rates, meteorology, and human activity patterns. In 

this assessment, we assume that individuals remain for 1 hour at 

the point of maximum ambient concentration as determined by the 

co-occurrence of peak emissions and worst-case meteorological 

 

30 U.S. EPA. National-Scale Air Toxics Assessment for 1996. (EPA 

453/R–01–003; January 2001; page 85.) 
Page 76 of 387 

conditions. These assumptions would tend to overestimate actual 

exposures since it is unlikely that a person would be located at 

the point of maximum exposure during the time of worst-case 

impact. 

d. Uncertainties in Dose-Response Relationships. 

There are uncertainties inherent in the development of the 

reference values used in our risk assessments for cancer effects 

from chronic exposures and non-cancer effects from both chronic 

and acute exposures. Some uncertainties may be considered 

quantitatively, and others generally are expressed in 

qualitative terms. We note as a preface to this discussion a 

point on dose-response uncertainty that is brought out in EPA’s 

2005 Cancer Guidelines; namely, that “the primary goal of EPA 

actions is protection of human health; accordingly, as an Agency 

policy, risk assessment procedures, including default options 

that are used in the absence of scientific data to the contrary, 

should be health protective.” (EPA 2005 Cancer Guidelines, 

pages 1–7.) This is the approach followed here as summarized in 

the next several paragraphs. A complete detailed discussion of 

uncertainties and variabilities in dose-response relationships 

is given in the residual risk documentation as referenced in 

section IV.A of this preamble, which is available in the docket 

for this action. 
Page 77 of 387 

Cancer URE values used in our risk assessments are those 

that have been developed to generally provide an upper bound 

estimate of risk. That is, they represent a “plausible upper 

limit to the true value of a quantity” (although this is usually 

not a true statistical confidence limit).31 In some 

circumstances, the true risk could be as low as zero; however, 

in other circumstances the risk could also be greater.32 When 

developing an upper bound estimate of risk and to provide risk 

values that do not underestimate risk, health-protective default 

approaches are generally used. To err on the side of ensuring 

adequate health-protection, EPA typically uses the upper bound 

estimates rather than lower bound or central tendency estimates 

in our risk assessments, an approach that may have limitations 

for other uses (e.g., priority-setting or expected benefits 

analysis). 

Chronic non-cancer reference (RfC and RfD) values represent 

chronic exposure levels that are intended to be healthprotective levels. Specifically, these values provide an 

estimate (with uncertainty spanning perhaps an order of 

magnitude) of daily oral exposure (RfD) or of a continuous 

inhalation exposure (RfC) to the human population (including 

sensitive subgroups) that is likely to be without an appreciable 

 

31 IRIS glossary (http://www.epa.gov/NCEA/iris/help_gloss.htm). 32 An exception to this is the URE for benzene, which is considered to 

cover a range of values, each end of which is considered to be equally 

plausible, and which is based on maximum likelihood estimates. 
Page 78 of 387 

risk of deleterious effects during a lifetime. To derive values 

that are intended to be “without appreciable risk,” the 

methodology relies upon an uncertainty factor (UF) approach 

(U.S. EPA, 1993, 1994) which includes consideration of both 

uncertainty and variability. When there are gaps in the 

available information, UF are applied to derive reference values 

that are intended to protect against appreciable risk of 

deleterious effects. UF are commonly default 

values,33 e.g., factors of 10 or 3, used in the absence of 

compound-specific data; where data are available, UF may also be 

developed using compound-specific information. When data are 

limited, more assumptions are needed and more UF are used. 

Thus, there may be a greater tendency to overestimate risk in 

the sense that further study might support development of 

reference values that are higher (i.e., less potent) because 

 

33 According to the NRC report, Science and Judgment in Risk Assessment

(NRC, 1994) “[Default] options are generic approaches, based on 

general scientific knowledge and policy judgment, that are applied to 

various elements of the risk assessment process when the correct 

scientific model is unknown or uncertain.” The 1983 NRC report, Risk 

Assessment in the Federal Government: Managing the Process, defined 

default option as “the option chosen on the basis of risk assessment 

policy that appears to be the best choice in the absence of data to 

the contrary” (NRC, 1983a, p. 63). Therefore, default options are not 

rules that bind the Agency; rather, the Agency may depart from them in 

evaluating the risks posed by a specific substance when it believes 

this to be appropriate. In keeping with EPA’s goal of protecting 

public health and the environment, default assumptions are used to 

ensure that risk to chemicals is not underestimated (although defaults 

are not intended to overtly overestimate risk). See EPA 2004, An 

examination of EPA Risk Assessment Principles and Practices, 

EPA/100/B–04/001 available at: http://www.epa.gov/osa/pdfs/ratffinal.pdf. 
Page 79 of 387 

fewer default assumptions are needed. However, for some 

pollutants it is possible that risks may be underestimated. 

While collectively termed “UF,” these factors account for a 

number of different quantitative considerations when using 

observed animal (usually rodent) or human toxicity data in the 

development of the RfC. The UF are intended to account for: 

(1) Variation in susceptibility among the members of the human 

population (i.e., inter-individual variability); (2) uncertainty 

in extrapolating from experimental animal data to humans (i.e., 

interspecies differences); (3) uncertainty in extrapolating from 

data obtained in a study with less-than-lifetime exposure (i.e., 

extrapolating from sub-chronic to chronic exposure); (4) 

uncertainty in extrapolating the observed data to obtain an 

estimate of the exposure associated with no adverse effects; and 

(5) uncertainty when the database is incomplete or there are 

problems with the applicability of available studies. Many of 

the UF used to account for variability and uncertainty in the 

development of acute reference values are quite similar to those 

developed for chronic durations, but they more often use 

individual UF values that may be less than 10. UF are applied 

based on chemical-specific or health effect-specific information 

(e.g., simple irritation effects do not vary appreciably between 

human individuals, hence a value of 3 is typically used), or 

based on the purpose for the reference value (see the following 
Page 80 of 387 

paragraph). The UF applied in acute reference value derivation 

include: (1) Heterogeneity among humans; (2) uncertainty in 

extrapolating from animals to humans; (3) uncertainty in lowest 

observable adverse effect (exposure) level to no observable 

effect (exposure) level adjustments; and (4) uncertainty in 

accounting for an incomplete database on toxic effects of 

potential concern. Additional adjustments are often applied to 

account for uncertainty in extrapolation from observations at 

one exposure duration (e.g., 4 hours) to derive an acute 

reference value at another exposure duration (e.g., 1 hour). 

Not all acute reference values are developed for the same 

purpose and care must be taken when interpreting the results of 

an acute assessment of human health effects relative to the 

reference value or values being exceeded. Where relevant to the 

estimated exposures, the lack of threshold values at different 

levels of severity should be factored into the risk 

characterization as potential uncertainties. 

Although every effort is made to identify peer-reviewed 

reference values for cancer and non-cancer effects for all 

pollutants emitted by the sources included in this assessment, 

some pollutants have no peer-reviewed reference values for 

cancer or chronic non-cancer or acute effects. Since exposures 

to these pollutants cannot be included in a quantitative risk 
Page 81 of 387 

estimate, an understatement of risk for these pollutants at 

environmental exposure levels is possible. 

Additionally, chronic reference values for several of the 

compounds included in this assessment are currently under EPA 

IRIS review and revised assessments may determine that these 

pollutants are more or less potent than the current value. We 

may re-evaluate residual risks for the final rulemaking if, as a 

result of these reviews, a dose-response metric changes enough 

to indicate that the risk assessment supporting this notice may 

significantly understate human health risk. 

e. Uncertainties in the Multipathway and Environmental Effects 

Assessment. 

We generally assume that when exposure levels are not 

anticipated to adversely affect human health, they also are not 

anticipated to adversely affect the environment. We generally 

rely on the facility-specific levels of PB-HAP emissions to 

determine whether a full assessment of the multi-pathway and 

environmental effects is necessary. Because facility-specific 

PB-HAP emission levels were so far below levels which would 

trigger a refined assessment of multi-pathway impacts, we are 

confident that these types of impacts are insignificant for 

these source categories. 

f. Uncertainties in the Facility-Wide Risk Assessment. 
Page 82 of 387 

The same uncertainties discussed above exist with regard to 

the facility-wide risk assessments. Additionally, the degree of 

uncertainty associated with facility-wide emissions and risks is 

generally greater because we have not completed our review of 

emissions data for source categories not currently undergoing an 

RTR review. 

g. Uncertainties in the Demographic Analysis. 

Our analysis of the distribution of risks across various 

demographic groups is subject to the typical uncertainties 

associated with census data (e.g., errors in filling out and 

transcribing census forms), as well as the additional 

uncertainties associated with the extrapolation of census-block 

group data (e.g., income level and education level) down to the 

census block level. 

B. How did we perform the technology review?

 Our technology review is focused on the identification and 

evaluation of “developments in practices, processes, and control 

technologies.” If a review of available information identifies 

such developments, then we conduct an analysis of the technical 

feasibility of requiring the implementation of these 

developments, along with the impacts (costs, emission 

reductions, risk reductions, etc.). We then make a decision on 

whether it is necessary to amend the regulation to require these 

developments. 
Page 83 of 387 

Based on specific knowledge of each source category, we 

began by identifying known developments in practices, processes, 

and control technologies. For the purpose of this exercise, we 

considered any of the following to be a “development”: 

• Any add-on control technology or other equipment that was 

not identified and considered during MACT development; 

• Any improvements in add-on control technology or other 

equipment (that was identified and considered during MACT 

development) that could result in significant additional 

emission reduction; 

• Any work practice or operational procedure that was not 

identified and considered during MACT development; and 

• Any process change or pollution prevention alternative that 

could be broadly applied that was not identified and 

considered during MACT development. 

In addition to looking back at practices, processes, or 

control technologies reviewed at the time we developed the MACT 

standard, we reviewed a variety of sources of data to aid in our 

evaluation of whether there were additional practices, 

processes, or controls to consider. One of these sources of 

data was subsequent air toxics rules. Since the promulgation of 

the MACT standards for the source categories addressed in this 

proposal, EPA has developed air toxics regulations for a number 

of additional source categories. In these subsequent air toxic 
Page 84 of 387 

regulatory actions, we consistently evaluated any new practices, 

processes, and control technologies. We reviewed the regulatory 

requirements and/or technical analyses associated with these 

subsequent regulatory actions to identify any practices, 

processes, and control technologies considered in these efforts 

that could possibly be applied to emission sources in the source 

categories under this current RTR review. 

We also consulted EPA’s RACT/BACT/LAER Clearinghouse 

(RBLC). The terms "RACT," "BACT," and "LAER" are acronyms for 

different program requirements under the CAA provisions 

addressing the national ambient air quality standards. Control 

technologies, classified as RACT (Reasonably Available Control 

Technology), BACT (Best Available Control Technology), or LAER 

(Lowest Achievable Emission Rate) apply to stationary sources 

depending on whether the sources are existing or new, and on the 

size, age, and location of the facility. BACT and LAER (and 

sometimes RACT) are determined on a case-by-case basis, usually 

by state or local permitting agencies. EPA established the RBLC 

to provide a central data base of air pollution technology 

information (including technologies required in source-specific 

permits) to promote the sharing of information among permitting 

agencies and to aid in identifying future possible control 

technology options that might apply broadly to numerous sources 

within a category or apply only on a source-by-source basis. 
Page 85 of 387 

The RBLC contains over 5,000 air pollution control permit 

determinations that can help identify appropriate technologies 

to mitigate many air pollutant emission streams. We searched 

this database to determine whether any practices, processes, or 

control technologies are included for the types of processes 

used for emission sources (e.g., tanks or vents) in the source 

categories under consideration in this proposal. 

We also requested information from industry regarding 

developments in practices, processes, or control technology. 

Finally, we reviewed other information sources, such as State or 

local permitting agency databases and industry-supported 

databases. 

C. How did we perform the analyses for the other actions being 

proposed?

For several of the source categories considered in this 

proposal, we identified significant emission points that were 

not previously regulated under MACT. For these emission points, 

consistent with the requirements of CAA sections 112(d)(2) and 

(3), we identified the MACT floor for existing and new sources 

and considered beyond-the-floor options. 

We also reviewed the SSM provisions of each of the six MACT 

standards in light of Sierra Club v. EPA, 551 F.3d 1019. As 

part of this review, we evaluated available information and 
Page 86 of 387 

engaged industry concerning the type of activities and emissions 

that occur during periods of startup or shutdown. 

Finally, we identified potential revisions to these MACT 

standards to correct or clarify regulatory requirements. In the 

years since promulgation and compliance with the MACT standards, 

EPA has received comments and suggestions for improving the 

clarity of the MACT standards in general, as well as rulespecific comments for some individual MACT standards. These 

comments include such things as identification of editorial 

errors in the rule, clarification of existing rule text, 

regulatory obstacles to effective implementation of or 

compliance with the rule provisions. EPA has also independently 

identified these types of issues. We are proposing rule changes 

where appropriate. 

V. Analyses Results and Proposed Decisions 

 This section of the preamble provides background 

information on the MACT standards and source categories, the 

results of our RTR for each source category, our proposed 

actions to address significant unregulated emission points for a 

number of source categories, our proposed decisions concerning 

the SSM provisions in each of the six MACT standards, and the 

specific clarifications we are proposing for selected MACT 

standards. 
Page 87 of 387 

A. What are the results and proposed decisions for the Chromium 

Electroplating source categories?

1. Overview of the source categories and MACT Standard. 

 National Emission Standards for Chromium Emissions from 

Hard and Decorative Chromium Electroplating and Chromium 

Anodizing Tanks (Chromium Electroplating MACT standards) were 

promulgated on January 25, 1995 (60 FR 4963), and codified at 40 

CFR part 63, subpart N. The Chromium Electroplating MACT 

standards regulate emissions of chromium compounds from three 

related source categories: Hard Chromium Electroplating, 

Decorative Chromium Electroplating, and Chromium Anodizing. 

Within these source categories, the MACT standards apply to all 

plants, both major and area sources, regardless of size. 

The Hard Chromium Electroplating source category consists 

of facilities that plate base metals with a relatively thick 

layer of chromium using an electrolytic process. Hard chromium 

electroplating provides a finish that is resistant to wear, 

abrasion, heat, and corrosion. These facilities plate large 

cylinders and industrial rolls used in construction equipment 

and printing presses, hydraulic cylinders and rods, zinc die 

castings, plastic molds, engine components, and marine hardware. 

The Decorative Chromium Electroplating source category 

consists of facilities that plate base materials such as brass, 

steel, aluminum, or plastic with layers of copper and nickel, 
Page 88 of 387 

followed by a relatively thin layer of chromium to provide a 

bright, tarnish- and wear-resistant surface. Decorative 

chromium electroplating is used for items such as automotive 

trim, metal furniture, bicycles, hand tools, and plumbing 

fixtures. 

The Chromium Anodizing source category consists of 

facilities that use chromic acid to form an oxide layer on 

aluminum to provide resistance to corrosion. The chromium 

anodizing process is used to coat aircraft parts (such as wings 

and landing gears), as well as architectural structures that are 

subject to high stress and corrosive conditions. 

The HAP emission sources subject to the Chromium 

Electroplating NESHAP are the tanks in which the chromium 

deposition takes place. For hard chromium and decorative 

chromium electroplating facilities, the emission sources are 

electroplating tanks. For the Chromium Anodizing source 

category, the emission sources are anodizing tanks. 

The primary emission controls used by the facilities in 

these source categories include packed bed scrubbers, mesh pad 

mist eliminators, composite mesh pad (CMP) systems, high 

efficiency particulate air (HEPA) filters, and wetting 

agent/fume suppressants (WAFS). Most decorative chromium 

electroplating plants comply with the MACT standards by using 

WAFS in the tank bath to control surface tension, which in turn 
Page 89 of 387 

reduces emissions. Some plants use a combination of WAFS and 

add-on control to meet the MACT emission limits. If a facility 

controls emissions using an add-on control device, the tank is 

generally equipped with a hood and duct work to exhaust 

emissions through the control device and out the stack. 

However, when WAFS are used as the only means of emission 

control, the tanks often are not equipped with exhaust hoods. 

In such cases, emissions from the tank are fugitive and are 

exhausted to the outside using wall-mounted exhaust fans. 

We estimate that there are approximately 1,770 plants that 

are currently subject to the Chromium Electroplating MACT 

standards. Of these, we estimate that there are 790 hard 

chromium electroplating plants, 740 decorative chromium 

electroplating plants, and 240 chromium anodizing plants. A 

detailed description of how the number of each type of plant was 

estimated can be found in the Estimated Number of Chromium 

Electroplating Plants document available in the docket for this 

action. Some facilities perform more than one type of chromium 

electroplating or anodizing. For purposes of our estimates, we 

classified facilities as hard chromium, decorative chromium, or 

chromium anodizing based on the primary type of electroplating 

operation performed at the facility. Some chromium 

electroplating facilities electroplate items that are used 

internally in the manufacturing process at the same facility or 
Page 90 of 387 

within the same company. For example, some large printing 

facilities electroplate their printing rollers in house, and the 

chromium electroplating processes are located at the same site 

as the printing and publishing processes. 

2. What data were used in our risk analyses? 

For the Chromium Electroplating source categories, we 

compiled a preliminary data set using data in the 2005 NEI. A 

review of the NEI resulted in the identification of data for 122 

chromium electroplating facilities. These data were reviewed 

and the data for eight hard chromium and six decorative chromium 

electroplating plants were revised based on information in the 

facilities’ permits or permit applications. Additional data 

were available for 44 facilities through responses to a CAA 

section 114 information request that was sent to facilities for 

the Plating and Polishing Area Source rule. The data for these 

facilities were added to the NEI data set, and, as with the 

original data, represent actual emission levels for these 

electroplating and anodizing facilities. Most of these 

facilities have low emissions, which are generally less than 2 

pounds per year (lbs/yr). These 166 facilities now included in 

the 2005 NEI comprise approximately 9 percent of the estimated 

1,770 facilities covered by the MACT standards, and include 63 

hard chromium electroplating, 96 decorative chromium 

electroplating, and 7 chromium anodizing facilities. This data 
Page 91 of 387 

set of 166 facilities was modeled to determine the maximum 

individual cancer risk, the population cancer risk, the cancer 

incidence, and the maximum chronic non-cancer risk for the three 

source categories based on actual emissions. The maximum 

individual cancer risk and the maximum chronic non-cancer risk 

estimated from this data set were also compared to the maximum 

individual cancer risk and the maximum chronic non-cancer risk 

estimated from MACT-allowable emissions for the three source 

categories. 

To address the possibility that the small number of 

facilities included in the 166-facility data set might not be 

fully representative of the source categories and their risks, 

we developed an additional data set. In the development of this 

data set, we used “model plants” developed for the original MACT 

standard to represent the individual facilities. For hard and 

decorative chromium electroplating, we used three model plants 

(large, medium, and small) that represent average 

characteristics for each of these groups. For each of these 

plant sizes, there is an annual emissions rate (lbs/yr) that is 

derived from the design and operating parameters, and is 

specific to the size and type of model plant. For chromium 

anodizing, we have two model plants (large and small). The 

model plants were based on data collected during development of 

the original MACT standards from 1988 to 1993 from more than 100 
Page 92 of 387 

facilities that responded to an Information Collection Request 

(ICR) for the chromium electroplating and anodizing industry. 

Data from site visits and other information also were used in 

developing the model plants. A complete description of the 

model plants developed for the MACT standard is provided in the 

Background Information Document (BID) for the original MACT 

standard (Chromium Electroplating BID). 

 The basis for this additional data set is 1,629 chromium 

electroplating facilities with known addresses.34 For about half 

of these facilities, the type of electroplating performed is 

known, but the size of the facility is not known. For the 

remaining facilities, neither the type of chromium 

electroplating process or processes, nor the facility size is 

known. 

 For use in the risk analysis, the limited available data 

were used to divide these facilities into six groups. 

Facilities in three of the six groups were assigned to be hard 

chromium electroplating facilities. Those groups include: hard 

chromium facilities; facilities with combined hard chromium 

operations and other electroplating or anodizing; and facilities 

with unknown processes. Together, these three groups yielded a 

total of 1,219 plants, all of which we modeled as hard chromium 

 

34 There is some overlap between the 1,629 facilities with known 

addresses and the 166 facilities for which we have emissions data 

based on the NEI and the data collection request. 
Page 93 of 387 

electroplating facilities. This total, in addition to the 63 

hard chromium electroplating facilities in the 2005 NEI data 

set, yields a total of 1,282 facilities, which is substantially 

higher than the 790 hard chromium facilities that we estimate 

exist in the United States. However, because hard chromium 

facilities have the highest emissions among the three source 

categories, we made these selections as a conservative or 

health-protective assumption. 

 To represent the decorative chromium electroplating 

facilities, we combined two of the six groups of facilities; 

decorative chromium facilities and facilities that perform both 

decorative chromium and chromium anodizing. This results in 319 

decorative chromium facilities in this data set, which, even 

when combined with the 96 decorative chromium electroplating 

facilities in the 2005 NEI data set, is less than the 740 

facilities that we believe exist in the industry. Because we 

modeled all of the unknown electroplating type facilities as the 

highest-emitting hard chromium electroplating facilities, we 

consider this assessment to be conservative, even though it 

appears to under-represent decorative chromium facilities. 

 Similarly, the last of the six groups are all known 

chromium anodizing facilities. This group includes 73 

facilities, and, when combined with the 7 chromium anodizing 

facilities in the 2005 NEI data set, still represents only about 
Page 94 of 387 

a third of the 240 facilities chromium anodizing facilities. 

Again, we believe this is conservative because those facilities 

not modeled as chromium anodizing plants were modeled as the 

higher emitting hard chromium facilities in the analysis. 

 To estimate the risks for this assessment, we needed to 

establish estimated emissions for each of the electroplating and 

anodizing types. To ensure that we did not underestimate cancer 

risk to the most exposed individual, we originally planned to 

use the large plant emission factors that we had developed for 

the original MACT standard to represent all model plants for 

each type of chromium electroplating processing. In reviewing 

available emissions data, we found that, while the large plant 

emission factors adequately represent the average chromium 

emissions from known large decorative chromium electroplating 

and large chromium anodizing facilities, they are not 

representative of the average chromium emissions from large hard 

chromium electroplating facilities. 

 The emission factor for large hard chromium electroplating 

developed for the original MACT standard was 35.3 lbs/yr. 

However, in comparing this emission factor to available 

emissions data for individual facilities, we find that this 

emissions factor is unrealistically high and does not represent 

the average level of emissions for large facilities as we would 

expect to see under the current MACT standard. As explained 
Page 95 of 387 

more fully in the Model Plant Data Used to Estimate Risk from 

Chromium Electroplating Sources document available in the docket 

for this action, based on the large model plant design flow rate 

and operating hours, a large hard chromium model plant operating 

at the MACT emission limit of 0.015 milligrams per dry standard 

cubic meter (mg/dscm) would emit a maximum of only 23.6 lbs/yr 

of chromium compounds. Moreover, the available data on actual 

emissions for hard chromium electroplating plants indicate there 

are only 4 plants with annual emissions greater than 10 lbs/yr. 

As a result, we determined that the large size model plant 

emissions factor, as defined for the original MACT standard, is 

not representative of existing large hard chromium 

electroplating facilities on a nationwide basis. On the other 

hand, the emission factor associated with a medium size hard 

chromium electroplating model plant (9.26 lbs/yr) falls between 

the 90th percentile (8.04 lbs/yr) and the 95th percentile (11.6 

lbs/yr) of the available emissions data for hard chromium 

electroplating facilities. Because this emission factor, which 

was originally developed for medium sized facilities at the time 

the MACT standard was developed, is representative of the 

emissions from large facilities, the emissions factor of 

9.26 lbs/yr was used to represent current large hard chromium 

electroplating facilities. Thus, for purposes of this residual 
Page 96 of 387 

risk review, we refer to 9.26 lbs/yr as the emissions factor for 

a "large" hard chromium electroplating facility. 

 We believe the approach of using the “large” facility 

emissions factor to represent all facility sizes is reasonable 

to ensure that we did not underestimate maximum individual 

cancer risk. Although we believe that only a small percentage 

of the facilities are large, we recognize that we do not have 

emissions data for approximately 90 percent of the sources. 

Thus, by assuming all sources are large, we have ensured that we 

will not underestimate the maximum individual risk. 

 For hard chromium electroplating, the model plant emission 

factors for small, medium, and large facilities range from 0.55 

to 9.26 lbs/yr. While we expect only 10 percent of the 

facilities to be large, based on the distribution of model plant 

sizes developed for the MACT standard, we used the emissions 

factor for a large facility (9.26 lbs/yr) for all of the 1,219 

facilities that we considered as hard chromium electroplating 

facilities. Similarly, for decorative chromium electroplating, 

the emission factors for small, medium, and large facilities are 

0.065, 0.27, and 2.65 lbs/yr, respectively, and the large 

facility emissions factor was used in the risk assessment for 

decorative chromium. For the Decorative Chromium category, we 

estimate that only 5 percent of the facilities are large, based 

upon the distribution of decorative chromium plants nationwide 
Page 97 of 387 

when the original NESHAP were developed. Finally, for chromium 

anodizing, the emission factor for small facilities is 0.036 

lb/yr, and for large facilities, is 0.44 lb/yr. The large 

facility emissions factor (0.44 lb/yr) was used in the 

conservative analysis for all of the anodizing facilities even 

though we estimate that only 25 percent are large. 

Population risk indicators can be greatly overstated when 

highly conservative emission estimates are applied to every 

facility in the source category. Recognizing this fact, we 

performed a supplemental analysis to better address nationwide 

average emission levels and assess the sensitivity of our 

population risk estimates. Thus, as described further below, 

the supplemental analysis was performed to understand the degree 

to which the risk might be overstated, and, thus, how much 

weight to attach to the conservative analysis. The conservatism 

of this risk assessment is one factor that we consider in 

determining whether the risk is acceptable within the meaning of 

the Benzene NESHAP. 

For the supplemental analysis, we assigned unique emission 

factors to each of the 6 groups of facilities in our 1,629 

facility data set. These emission factors were developed to 

better estimate the average emissions for all of the sources 

within each group. The new emission factors are: 

• 2.24 lbs/yr for known hard chromium electroplating 

Comment [A1]: Consistent 

with page 113 language 
Page 98 of 387 

facilities, 

• 0.225 lb/yr for known decorative chromium electroplating 

facilities, 

• 0.137 lb/yr for known chromium anodizing facilities, 

• 1.23 lbs/yr for facilities with combinations of hard 

chromium electroplating and either decorative 

electroplating or anodizing, 

• 0.181 lb/yr for facilities with combinations of 

decorative electroplating and anodizing, and 

• 1.11 lbs/yr for facilities where the type of process 

(electroplating or anodizing) is unknown. 

 A detailed explanation for how these emission factors were 

derived can be found in the Model Plant Data Used to Estimate 

Risk from Chromium Electroplating Sources available in the 

docket for this action. These weighted average emission factors 

account for the plant type (hard chromium electroplating, 

decorative chromium electroplating, or chromium anodizing) and 

the distribution of plant sizes (large, medium, or small). For 

example, the average emissions factor for hard chromium 

electroplating (2.24 lbs/yr) is the weighted average of the 

model plant emission factors for large plants (10 percent of 

plants at 9.26 lbs/yr per plant), medium plants (20 percent of 

plants at 4.63 lbs/yr per plant, and small plants (70 percent of 
Page 99 of 387 

plants at 0.55 lb/yr per plant). This distribution of plant 

sizes is based on actual data collected during development of 

the original MACT rule. We have no reason to believe the 

distribution of facility sizes has changed significantly since 

then. 

 The uncertainties associated with both the conservative 

analysis and the supplemental analysis include the estimated 

distribution of plant types and sizes as well as the facility 

emissions factors. Although the type of plants used in the NEI 

analysis is based on a variety of reliable sources, including 

ICR responses for the Plating and Polishing NESHAP, trade 

association data, data from State agencies, and information from 

websites, we were unable to identify the plant type for nearly 

half of the data set. For those plants of unknown type, we used 

the highest emissions factor, which corresponds to a large hard 

chromium plant, in the conservative analysis. For the 

supplemental analysis, we developed an emissions factor using a 

weighted average across all plant types and sizes. For all 

plants that were modeled, we are soliciting additional 

information on actual and MACT-allowable emissions, plant type, 

and plant size. More information about the development of the 

model plants can be found in the Model Plant Data Used to 

Estimate Risk from Chromium Electroplating Sources document 

available in the docket for this action. 
Page 100 of 387 

In all the data sets, chromium compounds account for all 

the HAP emissions from the Chromium Electroplating and Chromium 

Anodizing source categories. For the Hard Chromium 

Electroplating source category, in the NEI-based data set, 

chromium VI compounds account for 98 percent of the emissions, 

with chromium III and chromium trioxide compounds comprising the 

remaining HAP. In both the highly conservative NEI model and 

supplemental nationwide average emissions model plant model, we 

made the conservative assumption that 100 percent of the 

emissions are chromium VI compounds. For the Decorative 

Chromium Electroplating source category, in the NEI-based data 

set, chromium VI compounds account for 94 percent of the 

emissions, with chromium III and chromium trioxide compounds 

comprising the remaining HAP. In both emission estimates, we 

made the conservative assumption that 100 percent of the 

emissions are chromium VI compounds. For the Chromium Anodizing 

source category, in the NEI-based data set, chromium VI 

compounds account for 99 percent of the emissions with chromium 

III compounds comprising the remaining HAP. In both emission 

estimates, we made the conservative assumption that 100 percent 

of the emissions are chromium VI compounds. 

3. What are the results of the risk assessments and analyses?

 We conducted an inhalation risk assessment for each of the 

three source categories: Hard Chromium Electroplating, 

Comment [A2]: Consistent 

with p 113 

Deleted: emission estimates
Page 101 of 387 

Decorative Chromium Electroplating, and Chromium Anodizing. 

Also, for each source category, we conducted an assessment of 

facility-wide risk, and performed a demographic analysis of 

population risks. As noted above, we developed two data sets 

for these source categories, one conservative approach based 

primarily on NEI data for 166 sources (assuming all plants are 

large), and the supplemental analysis based on model plant data 

for 1,629 sources. 

 The following tables present the combined results from the 

data sets. Table A.1 provides an overall summary of the maximum 

individual inhalation risk assessment results, and Table A.2 

provides population risk assessment results for the Hard 

Chromium Electroplating, Decorative Chromium Electroplating, and 

Chromium Anodizing source categories. 

Table A.1. Chromium Electroplating and Anodizing Maximum 

Individual Inhalation Risk Assessment Results* Maximum Individual 

Cancer Risk 

(in 1 million)2

Maximum 

Chronic Non-cancer 

TOSHI3

Source Category 

Number of 

Facilities 

(NEI/Model 

Plant)1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum OffSite Acute 

Non-cancer HQ4

Hard Chromium 

Electroplating 63/1,219 70 90 0.06 0.09 Not appliacable5

Decorative 

Chromium 

Electroplating 

96/337 70 70 0.06 0.06 Not 

appliacable5

Chromium 

Anodizing 7/73 5 5 0.004 0.004 Not appliacable5

* All results are for impacts out to 50 km from each source in the categories. 

1

 Number of facilities evaluated in the risk analysis: the first number 

refers to the NEI data set, and the second number applies to the conservative 

emission estimate. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the Hard 

Chromium Electroplating, Decorative Chromium Electroplating, and Chromium 

Anodizing source categories is the respiratory system. 

4

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

Deleted: one 
Page 102 of 387 

shown use the lowest available acute threshold value, which, in most cases, 

is the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section IV.A. of this preamble for 

explanation of acute threshold values. 

5

 NA = not applicable. There are no HAP with acute dose-response benchmark 

values, so no acute HQ were calculated for these source categories. See 

section IV.A of this preamble for an explanation of acute threshold values. 

Table A.2. Chromium Electroplating and Anodizing Population 

Risk Inhalation Risk Assessment Results

Conservative 

Assessment 

Population 

at Risk 

Supplemental 

Assessment 

Population 

at Risk Source 

Category 

Number of 

Facilities 

(NEI/Model 

Plant) ≥ 1-in-1 

Million 

≥ 10-in1 

Million 

Conservative 

Annual 

Cancer 

Incidence 

(cases per 

year) ≥ 1-in-1 

Million 

≥ 10-in1 

Million 

Supplemental 

Annual 

Cancer 

Incidence 

(case per 

year) 

Hard Chromium 

Electroplating 63/1,219 14,200,000 71,000 0.8 360,000 5,100 0.1 

Decorative 

Chromium 

Electroplating 

96/337 390,000 4,000 0.08 30,000 1,300 0.01 

Chromium 

Anodizing 7/73 2,700 0 0.003 540 0 0.001 

 As shown in Table A.1, the results of the inhalation risk 

assessment for the Hard Chromium Electroplating source category 

indicate the maximum lifetime individual cancer risk could be as 

high as 70-in-1 million, based on actual emissions, and as high 

as 90-in-1 million based on allowable emissions. This maximum 

individual cancer risk is based on the highest risk facility out 

of the 63 actual facilities and the 1,219 model plants. The 

highest risk facility is one for which we have design and 

operating data, and we believe it is also both the largest and 

highest emitting hard chromium electroplating facility in the 

United States. Thus, we believe this level accurately reflects 

the maximum individual exposure. The maximum chronic non-cancer 

TOSHI value could be 0.06, based on the actual emissions level, 
Page 103 of 387 

and up to 0.09 based on allowables. This value is also based on 

known emission levels from the largest facility in the nation. 

A non-cancer TOSHI of one or less is not of human health 

concern. 

 The total estimated national cancer incidence from hard 

chromium electroplating facilities based on the conservative 

model actual emission levels is 0.8 excess cancer cases per 

year, or one case in every 1.25 years for the conservative 

assessment. Our conservative risk assessment shows 14.2 million 

people exposed to a cancer risk greater than 1-in-1 million and 

71,000 people exposed to a cancer risk of at least 10-in-1 

million. 

 As noted above, we conducted a supplemental analysis to 

compare to the conservative modeling, and determine the weight 

to give to the conservative risk analysis. That supplemental 

analysis estimates 0.1 excess cancer cases per year, or one case 

in every 10 years. Additionally, it estimates a population 

exposure of 360,000 people at 1-in-1 million cancer risk. For a 

cancer risk of at least 10-in-1 million, the population exposed 

decreases to 5,100. 

 Based on the 2005 NEI data set for the Decorative Chromium 

Electroplating source category, the maximum lifetime individual 

cancer risk could be as high as 70-in-1 million, and the maximum 

chronic non-cancer TOSHI value could be up to 0.06, based on the 
Page 104 of 387 

actual emissions level.35 We do not believe the maximum lifetime 

individual cancer risk and the maximum chronic non-cancer TOSHI 

value would be any higher than this based on allowable 

emissions. The total estimated population risks from the 

conservative risk assessment of the decorative chromium 

electroplating facilities based on actual emission levels is 

390,000 people exposed to a cancer risk greater than 1-in-1 

million and 0.08 excess cancer cases per year, or one case in 

every 12 years.36 

 Based on the 2005 NEI data set for the Chromium Anodizing 

source category, the maximum lifetime individual cancer risk 

could be as high as 5-in-1 million and the maximum chronic noncancer TOSHI value could be up to 0.004, based on the actual 

emissions level. The total estimated population risks from the 

conservative assessment of the chromium anodizing facilities 

based on actual emission levels is 2,700 people exposed to a 

 

35 There is uncertainty regarding the operating status of the facility 

associated with the maximum lifetime individual cancer risk. Prior to 

any final rulemaking action, we will investigate this situation and 

revise the risk analysis and results accordingly. 

36 Based on our conservative risk assessment, we believe the risks are 

low, and, as explained further below, are proposing that the risks are 

acceptable for the Decorative Chromium source category. Although we 

did not need to consider the supplemental analysis that we conducted 

for Decorative Chromium to help guide our conclusion about the 

uncertainty of the risk assessment results, we note that the 

supplemental assessment shows 30,000 people exposed to a cancer risk 

greater than 1-in-1 million and 0.01 excess cancer case per year, or 

one case in every 100 years. 
Page 105 of 387 

cancer risk greater than 1-in-1 million and 0.003 excess cancer 

cases per year, or one case in every 333 years.37 

 Also, as there were no reported emissions of PB–HAP for 

these three source categories, we do not expect the potential 

for human health multipathway risks or adverse environmental 

impacts. 

 Our analyses of potential differences between actual 

emission levels and emissions allowable under the MACT standards 

are based on emissions test data from specific facilities. A 

comparison of these test results to allowable emissions at these 

facilities indicates that the ratio of MACT-allowable to actual 

emissions varies considerably from facility to facility. As a 

result, a uniform factor was not available to apply to all 

facilities. However, for the Hard Chromium Electroplating 

source category, we did evaluate the facility that was modeled 

as having the highest maximum individual lifetime cancer risk 

(70-in-1 million) based on actual emissions. Our analysis 

indicates that this facility, if operated at the allowable 

emissions limit, could have a maximum individual lifetime cancer 

 

37 Based on our conservative risk assessment, we believe the risks are 

low, and, as explained further below, are proposing that the risks are 

acceptable for the Chromium Anodizing source category. Although we 

did not need to consider the supplemental analysis that we conducted 

for Chromium Anodizing to help guide our conclusion about the 

uncertainty of the risk assessment results, we note that the 

supplemental assessment shows 540 people exposed to a cancer risk 

greater than 1-in-1 million and 0.001 excess cancer case per year, or 

one case in every 1,000 years. 
Page 106 of 387 

risk as high as 90-in-1 million. Furthermore, the available 

data indicate that no other hard chromium electroplating 

facility would have a cancer risk that high if operated at the 

allowable emissions limit. 

 For the Decorative Chromium Electroplating source category, 

we performed a similar analysis of the available data and 

concluded that the maximum individual lifetime cancer risk would 

not exceed 70-in-1 million for any facility that operated at the 

allowable emissions limit. As stated earlier, because most 

chromium anodizing facilities use WAFS, we believe actual 

emissions are essentially the same as allowable emissions. 

Thus, we believe that the MIR based on allowable emissions would 

be the same as that based on actual emissions, i.e., 5-in-1 

million. 

 Table A.3 displays the results of the facility-wide risk 

assessment for actual emissions of all sources at the facility 

as reported in the NEI. We did not perform a facility-wide risk 

assessment based on allowable emissions, as explained in the 

documentation referenced in section IV.A of this preamble, which 

is available in the docket for this action. 

Table A.3. Chromium Electroplating and Anodizing Facility-Wide 

Risk Assessment Results

Source 

Category 

Maximum 

Facility-Wide 

Individual 

Cancer Risk 

(in 1 million) 

Source 

Category 

Contribution 

to this 

Maximum 

Facility-wide 

Maximum 

Facility-Wide 

Chronic Noncancer TOSHI 

Source 

Category 

Contribution 

to this 

Maximum 

Facility-wide 
Page 107 of 387 

Individual 

Cancer Risk1

Chronic Noncancer TOSHI1

Hard Chromium 

Electroplating 90 <1% 2 <1% 

Decorative 

Chromium 

Electroplating 

90 7% 0.8 <1% 

Chromium 

Anodizing 20 75% 0.2 <1% 

1

 Percentage shown reflects source category contribution to the maximum 

facility-wide risks at the facility with the maximum risk value shown. 

 As shown in Table A.3, the maximum individual cancer risks 

from all HAP emissions at facilities that perform hard chromium 

electroplating, decorative chromium electroplating, and chromium 

anodizing are estimated to be 90-in-1 million, 90-in-1 million, 

and 20-in-1 million, respectively. For the facilities where 

these maximum risk values occur, the estimated proportion of the 

cancer risk attributable to the hard chromium electroplating, 

decorative chromium electroplating, and chromium anodizing 

processes is less than 1 percent, 7 percent, and 75 percent, 

respectively. The highest facility-wide cancer risk for a 

facility that includes a hard chromium electroplating source is 

primarily driven by chemical production processes. We are 

currently developing a chemical manufacturing sector project38

and plan to address risk from these chemical production 

processes as part of that action. The highest facility-wide 

cancer risk for a facility that includes a decorative chromium 

 

38 This is one of several projects EPA is undertaking to establish and 

implement national emission-control measures for specific sectors of 

the economy by taking an integrated multipollutant approach to 

assessing and implementing additional emission controls using our 

existing regulatory frameworks. 
Page 108 of 387 

electroplating source is primarily driven by aerospace processes 

that will be addressed in a future residual risk review for the 

Aerospace Manufacturing and Rework Facilities source category. 

The highest facility-wide cancer risk for a facility that 

includes a chromium anodizing source is primarily driven by the 

chromium anodizing processes. The facility-wide maximum chronic 

non-cancer TOSHI values for facilities that include Hard 

Chromium Electroplating, Decorative Chromium Electroplating, and 

Chromium Anodizing source category processes are estimated to be 

2, 0.8, and 0.2, respectively. At the facilities where these 

maximum risk values occur, the estimated proportion of the noncancer risk attributable to the Hard Chromium Electroplating, 

Decorative Chromium Electroplating, and Chromium Anodizing 

source category processes is less than 1 percent for each source 

category. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on conservatively modeled emissions levels for the 

population living within 5 km of the facilities, among various 

demographic groups are provided in a report available in the 

docket for this action and summarized in Tables A.4, A.5, and 

A.6 below. These estimates of total population with risk 

exceeding 1-in-1 million differ from the risk estimates 

presented above because the demographic analysis uses a 5 km 

Deleted: actual 
Page 109 of 387 

radius and the risk assessment results provided above reflect 

use of a 50 km radius around all chromium electroplating 

facilities. 

Table A.4. Hard Chrome Electroplating Demographic Risk Analysis 

Results 

Population With Risk Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) 

Total 

(millio

ns) 

Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 70 13.1 52 23 29 34 0.6 22 20 

Facilitywide 90 13.1 52 23 29 34 0.6 22 20 

Table A.5. Decorative Chromium Electroplating Demographic Risk 

Analysis Results 

Population With Risk Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) 

Total 

(millions

) 

Minority 

% 

African 

American

% 

Other and

Multiracial 

% 

Hispanic

or Latino

% 

Native 

American

% 

Below 

the 

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 70 0.35 50 18 32 47 0.8 24 23 

Facilitywide 90 0.43 54 21 32 48 0.7 24 25 

Table A.6. Chromium Anodizing Demographic Risk Analysis Results 

Population With Risk Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) 

Total 

(millions

) 

Minorit

y 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below 

the 

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide 

n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 

5 0.0027 36 16 0 0 0.4 25 19 

Facilitywide 

20 0.0079 22 10 12 13 0.8 19 16 
Page 110 of 387 

 The results of the demographic analysis show that, for the 

population located within 5 km of Hard Chromium Electroplating 

source category, there are about 13.1 million people with cancer 

risks greater than 1-in-1 million for both the source category 

and facility-wide. Of this population at risk, 52 percent could 

be classified as a “Minority,” 34 percent are included in the 

“Hispanic or Latino” demographic group, 29 percent are included 

in the “Other and Multiracial” demographic group, 23 percent are 

included in the “African-American” demographic group, 22 percent 

are included in the “Below Poverty Level” demographic group, and 

20 percent are included in the “Over 25 Without a High School 

Diploma” demographic group. The percentage of the population 

within 5 km of a hard chromium electroplating facility and with 

a cancer risk greater than 1-in-1 million is higher than the 

typical distribution of these demographic groups across the 

United States. These demographic analyses are based on the 

conservative assessment results. 

 For the Decorative Chromium Electroplating source category, 

there are about 350,000 people with cancer risks greater than 1-

in-1 million for the source category and 430,000 people with 

cancer risks greater than 1-in-1 million facility-wide. Of this 

population at risk, 50 percent could be classified as a 

“Minority,” 47 percent are included in the “Hispanic or Latino” 
Page 111 of 387 

demographic group, 32 percent are included in the “Other and 

Multiracial,” demographic group, 18 percent are included in the 

“African-American” demographic group, 24 percent are included in 

the “Below Poverty Level” demographic group, and 23 percent are 

included in the “Over 25 Without a High School Diploma” 

demographic group. The percentage of the population within 5 km 

of a decorative chromium electroplating facility and with a 

cancer risks greater than 1-in-1 million is higher than the 

typical distribution of these demographic groups across the 

United States. The results of the demographic analysis for 

facility-wide emissions are similar to the results for the 

source category. 

 For the Chromium Anodizing source category, there are about 

2,700 people with cancer risks greater than 1-in-1 million and 

7,900 people with cancer risks greater than 1-in-1 million 

facility-wide. Of the population with cancer risks greater than 

1-in-1 million, 36 percent could be classified as a “Minority,” 

16 percent are included in the “African-American” demographic 

group, 25 percent are included in the “Below Poverty Level” 

demographic group, and 19 percent are included in the “Over 25 

Without a High School Diploma” demographic group. The 

percentage of the population within 5 km of a chromium anodizing 

facility and with a cancer risk greater than 1-in-1 million is 

higher than the typical distribution of these demographic groups 
Page 112 of 387 

across the United States. The results of the facility-wide 

demographic analysis are higher than the typical distribution of 

risks to the demographic groups across the United States, for 

the “Below Poverty Level” and the “Over 25 Without a High School 

Diploma” demographic groups, but are lower than these levels for 

the other demographic groups. 

 Details of these assessments and analyses can be found in 

the residual risk documentation as referenced in section IV.A of 

this preamble, which is available in the docket for this action. 

4. What are our proposed decisions on risk acceptability and 

ample margin of safety?

a. Risk Acceptability. 

 The risk analysis we performed for this proposal indicates 

that for the Hard Chromium Electroplating source category, the 

cancer risks to the individual most exposed is 70-in-1 million 

based on actual emissions and 90-in-1 million based on MACTallowable emissions. The maximum non-cancer risk level, which 

is low, is a TOSHI of 0.06 based on actual emissions and 0.09 

based on allowable emissions. These risks are due to estimated 

emissions of hexavalent chromium, which EPA describes as a known 

human carcinogen by the inhalation route of exposure. As 

explained above, both the MIR and the maximum non-cancer risk 

levels are based on emissions from what we believe is the 
Page 113 of 387 

highest risk hard chromium facility operating in the United 

States. 

 We further estimate that the excess cancer incidence could 

be as high as 0.8 cases per year, and that over 14 million 

people could be exposed to a cancer risk of 1-in-1 million or 

greater. These risk levels are based on a highly conservative 

risk assessment as described above. In summary, in this 

assessment we used (1) actual emissions data for 63 facilities 

and (2) emissions estimates that are reflective of average 

emissions for the highest emitting facilities for each one of an 

additional 1,219 facilities not in the original dataset. 

Because there are only 790 hard chromium facilities, and because 

only ten percent of the facilities would have this high an 

emissions rate, we believe that these conservative risk 

assessment results overstate cancer incidence and population 

exposure. 

 As noted above, we performed a supplemental analysis to 

assess the degree to which the conservative risk assessment may 

overstate risks, and, thus, to determine how heavily to weigh 

those risks in determining whether to find the risks acceptable. 

In this supplemental analysis we assessed these risks based on 

(1) the emissions data used in the conservative assessment for 

the 63 facilities for which we have actual facility emission 

information, and (2) revised emission data that better represent 
Page 114 of 387 

nationwide average emission levels for the 1,219 facilities. 

The supplemental assessment indicates that the excess cancer 

risks from hard chromium electroplating facilities is 0.1 cancer 

cases per year and 360,000 people exposed to a cancer risk of 1-

in-1 million or more, which is substantially less than we found 

with the conservative assessment. These results indicate that 

the estimated risks are uncertain and are highly sensitive to 

input assumptions and that the conservative assessment may 

substantially overstate risks. 

 The results of our demographic analysis indicate that 

minorities face disproportionate risks39 from exposure to 

emissions from this category (Tables A.4 – A.6). Although the 

demographic analysis was based on our conservative risk 

assessment modeling, we have no reason to believe that the 

results would be substantially different were we to re-run that 

analysis using the assumptions underlying the supplemental 

assessment. This is because the disparate impacts identified 

through our demographic analysis are reflective of the fact that 

many chrome facilities are located in inner city urban areas, 

and in or near residential neighborhoods more likely to be 

inhabited by minority and low income persons. We are concerned 

 

39 We estimated the percentage of people in the United States that are 

minority. We also estimated the percentage of people that live within 

5 km of each facility and have cancer risks greater than 1-in-1 

million that are minority. Where the percentage of people at risk is 

higher than the percentage nationwide, those minorities face 

disproportionate risks. 
Page 115 of 387 

about the potential disproportionate health risks from these 

urban facilities on minorities and those below the poverty 

level. We solicit comment on whether there may be pollution 

prevention efforts or other HAP emission reduction approaches 

that could mitigate the impacts that these facilities have on 

their immediate surroundings. We also recognize that, in 

addition to whatever controls are required in the final 

rulemaking for the Hard Chromium Electroplating source category, 

there may be other approaches, such as facility-specific 

compliance assistance, that could mitigate the impacts that 

these facilities have on their immediate surroundings. We 

solicit comment and supporting information to assist EPA in 

identifying measures to mitigate these disproportionate risks. 

 In accordance with the approach established in the Benzene 

NESHAP, EPA weighed all health risk measures and information, 

including the maximum individual cancer risk, the cancer 

incidence, the number of people exposed to a risk greater than 

1-in-1 million, the distribution of risks in the exposed 

population, and the uncertainty of our risk calculations in 

determining whether the risk posed by emissions from hard 

chromium facilities is acceptable. 

 As an initial matter, we note that the 90-in-1 million risk 

based on allowable emissions is approaching the “presumptive 

limit on maximum individual lifetime risk of approximately 1-in-
Page 116 of 387 

10 thousand [100-in-1 million]” recognized in the Benzene NESHAP 

(54 FR 38045). We also note that, based on our conservative 

analysis, there is a high level of cancer incidence of 0.8 

excess cancer cases per year nationwide, and a very large number 

(14.2 million) of people potentially exposed to a cancer risk 

greater than 1-in-1 million.40 However, we also recognize that 

our supplemental assessment based on alternative input 

assumptions concerning emissions (that better represent 

nationwide average emissions) indicate that the results of the 

conservative assessments are substantially overstated. Thus, 

there is great uncertainty about both the cancer incidence and 

the number of people exposed. 

 On the one hand, we acknowledge that the cancer incidence 

and number of people exposed to cancer risks of 1-in-1 million 

or greater are high based on our conservative analysis. On the 

other hand, we recognize the significant uncertainty of these 

risk estimates and the likelihood that they are overstated, 

based on the conservative nature of the assessment. The 

supplemental analysis highlights the sensitivity of our risk 

analysis to highly uncertain input assumptions and supports a 

determination that the population exposure and cancer incidence 

risk numbers are overstated. It shows substantially lower 

 

40 These comparisons refer to estimates of incidence and populations 

from risk assessments performed for other source categories previously 

covered by RTR risk assessments. 
Page 117 of 387 

cancer incidence (0.1 excess cases per year nationwide as 

opposed to 0.8) and number of people potentially exposed to a 

cancer risk of 1-in-1 million or more (360 thousand as opposed 

to 14.2 million). In addition, the distribution of risks in the 

exposed population shows the number of people exposed to a 

cancer risk greater than 10-in-1 million is 71,000 for the 

conservative assessment and 5,100 for the supplemental analysis. 

In determining whether risk is acceptable, we focus on the 

results of all aspects of the risk assessment. Because the MIR 

is less than 100-in-1 million, and because of the significant 

uncertainty of the cancer incidence and number of people 

exposed, which we believe are overstated based on the fact that 

our risk analysis was highly conservative, at this time, we are 

proposing that the risks from the Hard Chromium Electroplating 

source category are acceptable. We are proposing that the risks 

are acceptable, in large part, because we believe that the 

assumptions underlying the supplemental analysis presents a more 

realistic estimate of the emissions from hard chromium 

facilities. 

However, we are concerned by the results of our 

conservative risk analysis, especially the large number of 

people (including disproportionately affected populations) 

estimated to be exposed at a cancer risk above 1-in-1 million. 

We are also concerned about the level of uncertainty with our 

Deleted: may 

Deleted: very 
Page 118 of 387 

analysis given that we have limited information as to the number 

(and size) of the facilities. While our current proposal is 

supported by recognizing the uncertainty associated with the 

high risk levels from our conservative assessment and, as 

explained above, that uncertainty (as demonstrated by the 

supplemental analysis) points in the direction of an 

overstatement of risk, we would prefer to base a final rule on 

more complete and reliable information. The purpose of the 

residual risk standards under CAA section 112(f) is to ensure 

protection of public health and the environment. Thus, we 

believe it is important to develop a conservative risk analysis 

and err on the side of potential overestimation of risk analyses 

where we are missing data. In this case, we recognize that the 

assessment may be overly conservative, and we are considering 

additional methods for performing a conservative analysis. 

However, we believe additional information and data regarding 

the location, type and size of facilities will be important to 

performing any additional analysis that would err on the side of 

protectiveness without being overly conservative. At this time, 

we are not certain that we would take final action finding the 

risk to be acceptable based on the limited information currently 

available to the Agency. 

The comments and information that we receive on this 

proposal will be critical in making a final decision on 

Deleted: very 
Page 119 of 387 

acceptability. We are soliciting comment and data to help the 

Agency make an informed decision as it moves forward with this 

rulemaking. Specifically, with regard to each of the facilities 

listed in Appendix A to this preamble, we are seeking to 

identify (1) the actual annual emissions, if known; (2) which of 

the three source categories it falls within; and (3) whether, 

for hard chromium, it is a “large” or “small” facility within 

the definitions in 40 CFR 63.341(a). In particular, we are 

encouraging the States to provide EPA with better inventory data 

for sources within their States. Moreover, we are encouraging 

States to help identify sources that may be located near 

sensitive populations, such as located near schools or that may 

be located in communities with a significant minority 

population. To feel comfortable with a final decision finding 

the risk acceptable, we believe it is important to reduce the 

level of uncertainty associated with our current analyses. 

Thus, in light of the comments and any additional data (or lack 

thereof) that we receive during the comment period, we may 

determine that it is appropriate to issue a supplemental 

proposal in which we propose to find the risk unacceptable. If 

we issue a supplemental proposal in which we propose to find the 

risk unacceptable, we would be required to propose emissions 

standards or work practices that reduce risk to a level that is 

acceptable and provides an ample margin of safety. 
Page 120 of 387 

 For the Decorative Chromium Electroplating source category, 

the cancer risks to the individual most exposed is 70-in-1 

million, based on both actual and MACT-allowable emissions. 

Based on this cancer risk level and in consideration of other 

health measures and factors, including the cancer incidence (one 

case in every 12.5 years) and the low maximum non-cancer risk 

level (TOSHI of 0.06 based on both actual and MACT-allowable 

emissions), we propose that the risks from the Decorative 

Chromium Electroplating source category are acceptable. 

 For the Chromium Anodizing source category, the cancer 

risks to the individual most exposed is 5-in-1 million, based on 

both actual and allowable emissions. Based on this low cancer 

risk level and in consideration of other health measures and 

factors, including the cancer incidence (one case in every 250 

years) and the low maximum non-cancer risk level (TOSHI of 0.004 

based on actual emissions), we propose that the risks from the 

Chromium Anodizing source category are acceptable. 

b. Ample Margin of Safety. 

 Although we are proposing that the risks from these source 

categories are acceptable, risk estimates for individuals in the 

exposed population are above 1-in-1 million. Consequently, we 

considered whether the MACT standard provides an ample margin of 

safety. As part of this analysis, we investigated available 

emissions control options that might reduce the risk associated 
Page 121 of 387 

with chromium compound emissions from hard chromium 

electroplating, decorative chromium electroplating, and chromium 

anodizing operations. Table A.7 summarizes the nationwide costs 

and cost-effectiveness of these regulatory control options. 

Table A.7. Costs of Control Options for Chromium Electroplating 

Type of 

Facility 

Control 

Option 

Number of 

Affected 

Facilities 

Emission 

Reduction 

(TPY) 

Capital 

Costs 

($million) 

Annualized 

Costs 

($million/

yr) 

Costeffectiveness 

($million/

ton) 

MIR After 

Control 

(in-1- 

million) 

Large hard 

chromium 

electroplating 

HEPA 

filter 

retrofit 

132 1.0 35.1 18.4 36.3 6 

HEPA 

filter 

retrofit 

Small hard 658 0.4 66.0 33.9 59.3 6 

chromium 

electroplating CMP 

retrofit 392 0.2 36.6 11.1 33.1 10 

HEPA 

filter 

retrofit 

Decorative 740 0.1 109.0 47.8 486 4 

chromium 

electroplating CMP 

retrofit 644 0.051

 63.1 17.1 367 10 

HEPA 

filter 

retrofit 

240 0.02 43.9 17.9 895 < 1 Chromium 

anodizing CMP 

retrofit 198 0.0091

 22.9 5.6 649 2 

1 Based on an estimated control efficiency of 99.9 percent.

 For large hard chromium electroplating facilities, we 

evaluated the costs and emissions reductions associated with 

retrofitting existing tanks with HEPA filters. For small hard 

chromium electroplating facilities, we evaluated the same HEPA 

filter retrofit option, and also the option of retrofitting CMP 

systems on all tanks currently controlled with packed bed 

scrubbers. Retrofitting HEPA filters on existing tanks at large 

hard chromium electroplating plants would reduce nationwide 

emissions of chromium compounds by an estimated 1.0 TPY from the 

estimated baseline level of 1.10 TPY. The estimated capital and 

annualized costs for this option would be $35,100,000 and 
Page 122 of 387 

$18,430,000, respectively. The cost-effectiveness would be 

$36,300,000 per ton of HAP emissions reduced. Retrofitting HEPA 

filters on existing tanks at small hard chromium electroplating 

plants would reduce nationwide emissions of chromium compounds 

by an estimated 0.40 TPY from the estimated baseline level of 

0.42 TPY. The estimated capital and annualized costs for this 

option would be $65,980,000 and $33,860,000, respectively. The 

cost-effectiveness would be $59,300,000 per ton of HAP emissions 

reduced. Retrofitting CMP systems on all tanks currently 

controlled with packed bed scrubbers at small hard chromium 

electroplating plants would reduce nationwide emissions of 

chromium compounds by an estimated 0.19 TPY from the estimated 

baseline level of 0.37 TPY. The estimated capital and 

annualized costs for this option would be $36,640,000 and 

$11,050,000, respectively. The cost-effectiveness would be 

$33,100,000 per ton of HAP emissions reduced. The Benzene 

NESHAP emphasize the need to consider “costs and the economic 

impacts of control,” which implies some knowledge of 

affordability (54 FR 38046). The cost of the control options 

for hard chromium electroplating would impact over half of these 

facilities with estimated cost to sales ratios ranging from 8 

percent to 22 percent. A cost to sales ratio greater than 3 

percent may have a significant impact, including plant closure 

for many of these facilities. 
Page 123 of 387 

 These additional control requirements would reduce the 

maximum lifetime individual cancer risk from the Hard Chromium 

Electroplating source category to approximately 4-in-1 million, 

based on actual emissions. We estimate that, considering MACTallowable emissions levels, the maximum lifetime individual 

cancer risk from the Hard Chromium Electroplating source 

category would be reduced to approximately 6-in-1 million. The 

cancer incidence would be reduced to approximately 0.05 and the 

estimated number of people exposed higher than 1-in-1 million 

would be about 1 million. 

For decorative chromium electroplating, we evaluated the 

options of retrofitting HEPA filters on all existing tanks and 

the option of retrofitting CMP systems on the existing tanks 

that currently are not equipped with add-on control devices. 

Retrofitting HEPA filters on all existing decorative chromium 

electroplating tanks would reduce nationwide emissions of 

chromium compounds by an estimated 0.098 TPY from the estimated 

baseline level of 0.10 TPY. The estimated capital and 

annualized costs for this option would be $108,970,000 and 

$47,800,000, respectively. The cost-effectiveness would be 

$486,000,000 per ton of HAP emissions reduced. Retrofitting CMP 

systems on all decorative chromium electroplating tanks that 

currently do not have add-on controls would reduce nationwide 

emissions of chromium compounds by an estimated 0.05 TPY from 
Page 124 of 387 

the estimated baseline level of 0.10 TPY. The estimated capital 

and annualized costs for this option would be $63,100,000 and 

$17,100,000, respectively. The cost-effectiveness for this 

option would be $367 million per ton of HAP emissions reduced. 

The additional control requirements for HEPA filters would 

reduce the maximum lifetime individual cancer risk from the 

Decorative Chromium Electroplating source category to 

approximately 4-in-1 million, based on actual emissions. 

Because we believe the actual emissions are essentially the same 

as the MACT-allowable emissions for the Decorative Chromium 

Electroplating source category, we estimate no difference 

between the risks from the allowable emission level and the 

actual emission level. 

 For chromium anodizing, we evaluated the options of 

retrofitting HEPA filters on all existing tanks and the option 

of retrofitting CMP systems on the existing tanks that currently 

are not equipped with add-on control devices. Retrofitting HEPA 

filters on all existing chromium anodizing tanks would reduce 

nationwide emissions of chromium compounds by an estimated 0.020 

TPY from the estimated baseline level of 0.021 TPY. The 

estimated capital and annualized costs for this option would be 

$43,860,000 and $17,900,000, respectively. The costeffectiveness would be $895,000,000 per ton of HAP emissions 

reduced. Retrofitting CMP systems on all chromium anodizing 
Page 125 of 387 

tanks that currently do not have add-on controls would not 

significantly reduce emissions. The estimated capital and 

annualized costs for this option would be $22,900,000 and 

$5,600,000, respectively. The cost-effectiveness for this 

option would be $649 million per ton of HAP emissions reduced. 

The additional control requirements for HEPA filters would 

reduce the maximum lifetime individual cancer risk from the 

Chromium Anodizing source category to less than 1-in-1 million, 

based on actual emissions. Because we believe the actual 

emissions are essentially the same as the MACT-allowable 

emissions for the Chromium Anodizing source category, we 

estimate the risk reduction based on allowable emissions to be 

the same as that for the actual emissions. 

Our risk analysis results show cancer risks to the 

individual most exposed of 70-in-1 million and 5-in-1 million 

based on actual and MACT-allowable emissions, respectively, for 

the Decorative Chromium Electroplating and Chromium Anodizing 

source categories. For both of these categories, the cancer 

incidence is less than 0.01 cases per year. For decorative 

chromium electroplating, the number of people exposed to a 

cancer risk of 1-in-1 million or more is approximately 390,000. 

For chromium anodizing, the number of people exposed to a cancer 

risk of 1-in-1 million or more is approximately 2,700. 
Page 126 of 387 

For the Hard Chromium Electroplating source category, our 

risk analysis shows cancer risks to the individual most exposed 

are 70-in-1 million based on actual emissions levels and 90-in-1 

million based on MACT-allowable emissions. The cancer incidence 

for this source category could be as high as 0.8 cases per year, 

and could be over 14 million people exposed to cancer risks of 

1-in-1 million or greater due to emissions from hard chromium 

electroplating sources using highly conservative assumptions. 

As we stated previously, we believe we overestimated hard 

chromium electroplating emissions, the number of plants that 

perform hard chromium electroplating, and, therefore, that the 

risks from the resulting analyses are also overstated. Our 

supplemental risk analysis for this source category indicates a 

cancer incidence of 0.1 cases per year and 360,000 people 

exposed to cancer risks of greater than 1-in-1-million. This 

analysis indicates that the risk levels in the assessment are 

highly uncertain and err on the side of being conservative. 

Our analyses also show that, for these source categories, 

there is no potential for an adverse environmental effect or 

human health multipathway effects, and that acute and chronic 

non-cancer health impacts are unlikely. Our additional analysis 

of facility-wide risks showed that the maximum facility-wide 

cancer risk is 90-in-1 million, and that the maximum chronic 

non-cancer risks are unlikely to cause health impacts. Our 
Page 127 of 387 

additional analysis of the demographics of the exposed 

population shows that minorities face disproportionate risk from 

exposure to emissions from this category 

We do not believe there is a significant risk reduction 

from the housekeeping measures we are proposing under CAA 

section 112(d)(6). However, we are requesting information on 

any risk reductions from these housekeeping practices and 

whether we should consider adopting these practices under CAA 

section 112(f)(2). 

We considered all these factors in our ample margin of 

safety decision, and concluded that the costs of the options 

analyzed are not reasonable considering the emissions reductions 

and cancer health benefits potentially achievable with the 

controls. As a result, we propose that the existing MACT 

standard provides an ample margin of safety (considering cost, 

technical feasibility, and other factors) to protect public 

health for all three of these source categories. Thus, we are 

proposing to re-adopt the existing MACT standard to satisfy 

section 112(f) of the CAA. 

 While we propose that the existing MACT standard for the 

Hard Chromium Electroplating source category is acceptable and 

provides an ample margin of safety, we are proposing additional 

requirements under CAA section 112(d)(6), as discussed below. 

Notwithstanding our proposal that the risks are acceptable, we 
Page 128 of 387 

remain concerned that up to 14.2 million people may be exposed 

to cancer risks of 1-in-1 million or greater, and that there are 

disparities in risks for some demographic groups. While we are 

rejecting the option of adding HEPA filters or CMP as not costeffective, we are specifically requesting comment on whether 

there are any cost-effective controls that may be able to reduce 

these risks. In particular, we are requesting States to 

identify any controls they have already required for these 

facilities, any controls they are currently considering, or any 

other controls of which they may be aware. We are also 

soliciting comment on whether our cost estimates for these 

options are accurate and whether these controls may be more 

cost-effective. 

 In summary, we propose that the risks posed by these source 

categories are acceptable. We are also proposing that the 

current MACT standard provides an ample margin of safety to 

protect public health based on our conclusion that the controls 

available are not cost-effective in light of the additional 

health protection the controls would provide. Thus, we are 

proposing to re-adopt the existing MACT standard to satisfy 

section 112(f) of the CAA. 

5. What is our proposed decision on the technology review?

 To evaluate developments in practices, processes, and 

control technologies for the chromium electroplating source 
Page 129 of 387 

categories, several activities were performed. Public comments 

received on the proposed 2002 amendments to the Chromium 

Electroplating MACT standards (67 FR 38810, June 5, 2002) were 

reviewed to determine whether they identified any developments 

in practices, processes, or control technologies that warrant 

further consideration. A review was performed of the supporting 

documentation for the 2007 amendments to California's Airborne 

Toxic Control Measure (ATCM) for Chromium Plating and Chromium 

Anodizing Facilities. Finally, searches of the RBLC and the 

Internet were conducted to identify other practices, processes, 

or control technologies that could be applied to chromium 

electroplating.

 The 2004 amendments to the Chromium Electroplating MACT 

standards addressed three specific technology developments that 

occurred following promulgation of the original MACT standard: 

the use of WAFS for hard chromium electroplating emission 

control; instrumental differences in surface tension 

measurements for demonstrating compliance with electroplating 

bath surface tension limits; and enclosing hoods for 

electroplating tanks. Because those technology developments 

have already been addressed and we are not aware of any 

improvements to them, they are not discussed further. The 

following paragraphs describe all developments in practices, 

processes, and control technologies that we identified and that 
Page 130 of 387 

were thus considered for the technology review, along with our 

conclusions. 

a. Emission Elimination Device. 

An emission elimination device (EED), which is also 

referred to as a "Merlin cover," consists of a tank cover that 

includes a porous membrane that allows gases to escape, but 

captures droplets and mist emanating from the electroplating 

tank. While these tank covers are available, we do not believe 

any chromium electroplating or anodizing facilities are 

currently using an EED due to the impracticality of covering the 

electroplating tank while plating is underway. Because these 

devices are not known to be used in this industry and because it 

is unclear that they are feasible for these operations, we 

concluded that it is not necessary to revise the MACT standard 

to require this control under section 112 (d)(6). However, we 

request comment on tanks or processes in which an EED could 

practicably be used by chromium electroplating or anodizing 

facilities. 

b. HEPA Filters. 

Although HEPA filters have been on the market for decades, 

they were not considered to be a practical control method for 

electroplating tank emissions when the MACT standards were 

developed due to potential problems with clogging and the 

availability of several other types of mist eliminator 
Page 131 of 387 

technologies that had been proven to be effective in reducing 

emissions from electroplating tanks. However, in the past 

decade, facilities in California have increasingly used HEPA 

filters to meet the emission limits of the State's ATCM for 

Chromium Plating and Chromic Acid Anodizing Facilities. In 

October 2007, the California Air Resources Board (CARB) amended 

the ATCM to further tighten emission limits and to require HEPA 

filters on all new chromium electroplating and anodizing tanks. 

In those applications, HEPA filters act as a second stage of 

control, with the first stage generally consisting of a mesh pad 

mist eliminator or other device that removes large particles 

from the exhaust stream prior to the HEPA filter. Discussions 

with State and local agency staff in California indicate no 

technological problems with using HEPA filters for chromium 

electroplating emissions control. As part of this technology 

review, HEPA filters have been considered as a possible control 

option for sources subject to the Chromium Electroplating MACT 

standards. The costs of requiring HEPA filters were estimated, 

and are discussed above in section V.A.4.b of this preamble. In 

light of the high cost of this option as compared with the risk 

reductions it would achieve, we are proposing that it is not 

necessary to revise the MACT standard under section 112(d)(6) to 

require HEPA filters. However, we request comment on whether we 

should require HEPA filters for new source MACT. 
Page 132 of 387 

c. Wetting Agent Fume Suppressants (WAFS). 

 WAFS are used in most decorative chromium electroplating 

and chromium anodizing tanks and in many hard chromium 

electroplating tanks for emission control. Historically, the 

most effective types of WAFS have been based on perfluorooctyl 

sulfonate (PFOS). The PFOS-based WAFS used in the chromium 

electroplating industry are part of a family of chemical 

compounds categorized as long-chain perfluorinated chemicals 

(PFC). As noted in a 2006 EPA SAB report, SAB Review of EPA’s 

Draft Risk Assessment of Potential Human Health Effects 

Associated with PFOA and Its Salts41 and also in a 2010 

California Office of Health Hazard Assessment report, 

Perfluorooctane sulfonate (PFOS) and Its Salts and 

Transformation and Degradation Precursors,42 these compounds have 

persistent, bioaccumulative, and toxic characteristics and are a 

particular concern for children’s health. Although it has not 

been demonstrated that these compounds cause adverse effects to 

humans, studies have shown significant adverse effects to 

laboratory animals, wildlife, and groundwater. 

There are now several types of WAFS on the market that do 

not include PFOS chemicals and have been proven effective for 

 

41 This report is available at 

http://yosemite.epa.gov/sab%5Csabproduct.nsf/A3C83648E77252828525717F0

04B9099/$File/sab_06_006.pdf

42 This report is available at 

http://www.oehha.org/prop65/CRNR_notices/pdf_zip/070910_PFOS_CIC.pdf
Page 133 of 387 

use in hard chromium and decorative chromium electroplating 

baths. Furthermore, these non-PFOS WAFS are not associated with 

adverse health effects. Although the non-PFOS WAFS have not 

been used extensively in the chromium anodizing industry, we are 

not aware of any technical reasons to preclude their use and 

effectiveness for chromium anodizing baths. In view of the 

increasing concern over the presence of long-chain PFC in the 

environment, and the fact that other types of WAFS are effective 

in chromium electroplating operations and are available at a 

reasonable cost, we are proposing under CAA section 112 (d)(6) 

to no longer allow the addition of PFOS-based WAFS to tanks as a 

control method for these source categories. 

We are proposing to no longer allow the addition of PFOSbased WAFS to hard and decorative chromium electroplating tanks 

and for chromium anodizing tanks as the method of controlling 

chromium emissions. For new sources, no PFOS-based WAFS could 

be used effective upon startup. For existing sources, no PFOSbased WAFS could be added to the electroplating or anodizing 

tanks beginning 3 years after promulgation of the final 

amendments; however, the tanks may continue operating with the 

remaining PFOS-based WAFS in them after that date until it is 

depleted. Under these amendments, these requirements would be 

specified in 40 CFR 63.342(c)(1)(iv) and (2)(vi) for hard 

chromium electroplating tanks, 40 CFR 63.342(d)(3) for 
Page 134 of 387 

decorative chromium electroplating and chromium anodizing tanks, 

and 40 CFR 63.342(e)(2) for decorative chromium electroplating 

tanks that use a trivalent chromium bath. A definition of PFOSbased fume suppressants also would be added to 40 CFR 63.341. 

d. Housekeeping Procedures. 

We are also proposing under CAA section 112 (d)(6) to 

incorporate several housekeeping requirements into 40 CFR 

63.342(f). In our review of the 2007 amendments to California's 

ATCM for Chromium Plating and Chromic Acid Anodizing Facilities, 

we found this rule required several housekeeping procedures that 

were not included in the housekeeping procedures required by the 

Chromium Electroplating MACT standards. These measures would 

potentially reduce fugitive chromium emissions from chromium 

electroplating and anodizing operations. In view of the 

implementation of these procedures in California and the 

potential for fugitive emissions reductions, we are proposing to 

add these procedures to the Chromium Electroplating MACT 

standards. The proposed housekeeping procedures would include 

storage requirements for any substance that contains hexavalent 

chromium as a primary ingredient; controls for the dripping of 

bath solution resulting from dragout; splash guards to minimize 

overspray and return bath solution to the electroplating or 

anodizing tank; a requirement to promptly clean up or contain 

all spills of any substance containing hexavalent chromium; 
Page 135 of 387 

requirements for the routine cleaning or stabilizing of storage 

and work surfaces, walkways, and other surfaces potentially 

contaminated with hexavalent chromium; a requirement to install 

a barrier between all buffing, grinding, or polishing operations 

and electroplating or anodizing operations; and requirements for 

the storage, disposal, recovery, or recycling of chromiumcontaining wastes. The proposed housekeeping procedures would 

be listed in a new Table 2 to 40 CFR 63.342. In addition, this 

proposed action would require owners and operators to 

incorporate these housekeeping procedures in the facility 

Operation and Maintenance Plan specified in section 40 CFR 

63.342(f)(3) and implement them, and a new definition would be 

added to 40 CFR 63.341(a) to clarify what is meant by the term 

“contains hexavalent chromium as a primary ingredient.” The 

proposed compliance date for implementing the housekeeping 

procedures would be 6 months after promulgation of the final 

amendments. 

6. What are the other actions we are proposing?

a. SSM Provisions.

Consistent with Sierra Club v. EPA, EPA is proposing that 

standards in this rule would apply at all times. The existing 

MACT standards for these three source categories already 

specifies that the emission limitations apply “during periods of 

startup and shutdown” but not during malfunctions. We are 
Page 136 of 387 

proposing to revise this paragraph to remove the sentence 

indicating that the emission limitations do not apply during 

malfunctions. We are maintaining the requirements to develop 

and implement a written operations and maintenance plan, along 

with the malfunction-associated reporting and recordkeeping 

requirements in sections 63.346 and 63.347 with minor revisions. 

We are proposing to add language to 63.344(a) to clarify the 

conditions during which performance tests shall be conducted and 

to specify in Table 1 that the performance test specifications 

in paragraph 63.7(e)(1) of the General Provisions do not apply. 

We are also proposing to add a general duty provision to 

minimize emissions into section 63.342(a)(1). In addition, we 

are proposing to promulgate an affirmative defense against civil 

penalties for exceedances of emission standards caused by 

malfunctions, as well as criteria for establishing the 

affirmative defense. EPA has attempted to ensure that we have 

not incorporated into the proposed regulatory language any 

provisions that are inappropriate, unnecessary, or redundant in 

the absence of the SSM exemption. We are specifically seeking 

comment on whether there are any such provisions that we have 

inadvertently incorporated or overlooked. 

b. Rule Improvements. 

 In addition, we identified the need for revisions of the 

standards to correct editorial errors, make clarifications, or 
Page 137 of 387 

address issues with implementation or determining compliance 

with the rule provisions. 

Monitoring and Testing Requirements. We are proposing to 

revise 40 CFR 63.344(e), which addresses compliance provisions 

for multiple sources controlled by a common add-on air pollution 

control device. This section of the MACT standard references 

testing by Method 306, without any mention of Method 306A. 

Since Method 306A is an alternative to Method 306, we are 

proposing to revise section 40 CFR 63.344(e) to clarify that 

testing can be performed by either Method 306 or Method 306A. 

 To correct inconsistencies between the amendments made to 

40 CFR part 63, subpart N in 2004 (69 FR 42885) and Method 306B, 

we are proposing to revise Method 306B, which specifies 

procedures for measuring the surface tension of chromium 

electroplating and anodizing baths. In addition, the proposed 

amendments would help to ensure that surface tension 

measurements made using stalagmometers are accurate. Under the 

proposed amendments, section 1.2 of Method 306B would be revised 

to clarify that the method also applies to hard chromium 

electroplating tanks. Section 11.1 would be revised to include 

procedures for checking the accuracy of, and cleaning, a 

stalagmometer before using the stalagmometer to measure surface 

tension. The proposed revisions to section 11.1 are consistent 

with the CARB ATCM for Hexavalent Chromium for Decorative and 
Page 138 of 387 

Hard Chrome plating and Chromic Acid Anodizing Facilities. 

Maintaining surface tension measuring devices is critical for 

obtaining accurate measurements. Method 306B currently 

references standard procedures for the use of tensiometers (ASTM 

Method D 1331-89), but not for the use of stalagmometers. The 

proposed amendment to section 11.1 would help to ensure that 

stalagmometers used to demonstrate compliance with surface 

tension limits are maintained and used properly. Finally, 

section 11.2 would be revised to account for the differences in 

surface tension limits, depending on the type of instrument used 

(tensiometer or stalagmometer). 

Rule Corrections. To eliminate a discrepancy between the 

Chromium Electroplating MACT standards in subpart N of part 63 

and the General Provisions in subpart A of part 63, this 

proposed action would also revise the trigger for semiannual 

compliance reports specified in 40 CFR 63.347(h)(2)(A) to be 

consistent with the trigger specified in the General Provisions. 

Subpart N currently provides that a semiannual report must be 

submitted if both the duration of excess emissions exceeds 

1 percent of the source operating time and the duration of air 

pollution control device malfunctions exceeds 5 percent of the 

source operating time during the reporting period; however, 40 

CFR 63.10(e)(3)(viii) of the General Provisions requires 

submitting a semiannual report if either condition occurs. We 
Page 139 of 387 

are proposing to revise 40 CFR part 63, subpart N to require 

semiannual reports to be submitted if either condition occurs. 

B. What are the results and proposed decisions for the Group I 

Polymers and Resins Production source categories?

 The National Emission Standards for Hazardous Air Pollutant 

Emissions: Group I Polymers and Resins were promulgated on 

September 5, 1996 (62 FR 46925), and codified at 40 CFR part 63, 

subpart U. The Polymers and Resins I MACT standard applies to 

major sources and regulates HAP emissions from nine source 

categories: Butyl Rubber Production, Epichlorohydrin Elastomers 

Production, Ethylene Propylene Rubber Production, HypalonTM

Production, Neoprene Production, Nitrile Butadiene Rubber 

Production, Polybutadiene Rubber Production, Polysulfide Rubber 

Production, and Styrene Butadiene Rubber and Latex Production. 

 The Polymers and Resins I MACT standards regulate HAP 

emissions resulting from the production of elastomers (i.e., 

synthetic rubber). An elastomer is a synthetic polymeric 

material that can stretch to at least twice its original length 

and then return rapidly to approximately its original length 

when released. Elastomers are produced via a 

polymerization/copolymerization process, in which monomers 

undergo intermolecular chemical bond formation to form a very 

large polymer molecule. Generally, the production of elastomers 
Page 140 of 387 

entails four processes: (1) Raw material (i.e., solvent) 

storage and refining; (2) polymer formation in a reactor (either 

via the solution process, where monomers are dissolved in an 

organic solvent, or the emulsion process, where monomers are 

dispersed in water using a soap solution); (3) stripping and 

material recovery; and (4) finishing (i.e., blending, aging, 

coagulation, washing, and drying). 

 Sources of HAP emissions from elastomers production include 

raw material storage vessels, front-end process vents, back-end 

process operations, wastewater operations, and equipment leaks. 

The “front-end” processes include pre-polymerization, reaction, 

stripping, and material recovery operations; and the “back-end” 

process includes all operations after stripping (predominately 

drying and finishing). Typical control devices used to reduce 

organic HAP emissions from front-end process vents include 

flares, incinerators, absorbers, carbon adsorbers, and 

condensers. In addition, hydrochloric acid formed when 

chlorinated organic compounds are combusted are controlled using 

scrubbers. Emissions from storage vessels are controlled by 

floating roofs or by routing them to a control device. 

 While emissions from back-end process operations can be 

controlled with control devices such as incinerators, the most 

common method of reducing these emissions is the pollution 

prevention method of reducing the amount of residual HAP that is 
Page 141 of 387 

contained in the raw product going to the back-end operations. 

Emissions from wastewater are controlled by a variety of 

methods, including equipment modifications (e.g., fixed roofs on 

storage vessels and oil water separators; covers on surface 

impoundments, containers, and drain systems), treatment to 

remove the HAP (steam stripping, biological treatment), control 

devices, and work practices. 

 Emissions from equipment leaks are typically reduced by 

leak detection and repair work practice programs, and in some 

cases, by equipment modifications. Each of the seven Group I 

Polymers and Resins Production source categories addressed in 

this proposal are discussed further below. 

1. Epichlorohydrin Elastomers Production. 

 Epichlorohydrin Elastomers Production is one of the source 

categories for which we proposed RTR decisions on October 10, 

2008. 

a. Overview of the source category. 

Epichlorohydrin elastomers are prepared from the 

polymerization or copolymerization of epichlorohydrin or other 

monomers. Epichlorohydrin elastomers are produced by a solution 

polymerization process, typically using toluene as the solvent 

in the reaction. The main epichlorohydrin elastomers are 

polyepichlorohydrin, epi-ethylene oxide (EO) copolymer, epiallyl glycidyl ether (AGE) copolymer, and epi-EOAGE terpolymer. 
Page 142 of 387 

Epichlorohydrin elastomers are widely used in the automotive 

industry. 

We identified one currently operating epichlorohydrin 

elastomers production facility subject to the Polymers and 

Resins I MACT standard. Toluene accounts for the majority of 

the HAP emissions from the epichlorohydrin elastomers production 

processes at this facility (approximately 44 TPY and 99 percent 

of the total HAP emissions by mass). This facility also 

reported relatively small emissions of epichlorohydrin and 

ethylene oxide. The majority of HAP emissions are from back-end 

process vents (approximately 82 percent of the total HAP by 

mass). We estimate that the MACT-allowable emissions (i.e., the 

maximum emission levels allowed if in compliance with the MACT 

standard) from this source category are approximately equal to 

the reported, actual emissions. For more detail about this 

estimate of the ratio of actual to MACT-allowable emissions, see 

the memo in the docket for this action describing the estimation 

of MACT-allowable emission levels and associated risks and 

impacts. 

b. What data were used in our risk analyses?

We initially created a preliminary data set for the 

Epichlorohydrin Elastomers Production source category using 

information we collected directly from industry on emissions 

data and emissions release characteristics. We also reviewed 
Page 143 of 387 

the emissions and other data to identify data anomalies that 

could affect risk estimates. On March 29, 2007, we published an 

ANPRM (72 FR 29287) for the express purpose of requesting 

comments on and updates to this data set, as well as to the data 

sets for the other source categories addressed in that ANPRM. 

Comments received in response to the ANPRM were reviewed and 

considered, and we made adjustments to the data set where we 

concluded the comments supported such adjustment. After making 

appropriate changes to the data set based on this public data 

review process, the data set on which we based the initial 

proposal was created. This data set was used to conduct the 

risk assessment and other analyses for the Epichlorohydrin 

Elastomers Production source category that formed the basis for 

the proposed RTR included in the October 10, 2008, proposal. 

We have continued to scrutinize the existing data set and 

have evaluated any additional data that became available 

subsequent to the October 10, 2008, proposal. Specific 

questions we had concerning current operations led us to develop 

a questionnaire and ask for updated emissions and emissions 

release characteristics information. This information was 

requested from the facility in May 2010 using the authority of 

section 114 of the CAA. We updated our data set for this source 

category based on the information received through this request. 

c. What are the results of the risk assessments and analyses?
Page 144 of 387 

 We have conducted a revised inhalation risk assessment for 

the Epichlorohydrin Elastomers Production source category. We 

have also conducted an assessment of facility-wide risk, and 

performed a demographic analysis of population risks. Table 

B.1.1 provides an overall summary of the results of the revised 

inhalation risk assessment. 

Table B.1.1. Epichlorohydrin Elastomers Production Revised 

Inhalation Risk Assessment Results* 

Maximum 

Individual 

Cancer Risk 

(in 1 million)2

Maximum 

Chronic Non-cancer 

TOSHI3

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population 

at Risk ≥

1-in-1 

Million 

Annual 

Cancer 

Incidence 

(cases 

per 

year) 

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum 

Off-site 

Acute Noncancer HQ4

1 10 10 800 0.0001 0.1 0.1 

HQREL = 0.2 

epichlorohy

drin * All results are for impacts out to 50 km from every source in the category. 

1

 Number of facilities evaluated in the risk analysis. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the 

Epichlorohydrin Elastomer Production source category is the respiratory 

system. 

4

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

shown use the lowest available acute threshold value, which, in most cases, 

is the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section IV.A. of this preamble for 

explanation of acute threshold values. 

 The inhalation risk modeling was performed using actual 

emissions level data. As shown in Table B.1.1, the results of 

the revised inhalation risk assessment indicated the maximum 

lifetime individual cancer risk could be as high as 10-in-1 

million, the maximum chronic non-cancer TOSHI value could be as 

high as 0.1, and the maximum off-facility-site acute HQ value 

could be as high as 0.2, based on the actual emissions level and 

the REL value for epichlorohydrin. The total estimated national 
Page 145 of 387 

cancer incidence from these facilities based on actual emission 

levels is 0.0001 excess cancer cases per year, or one case in 

every 10,000 years. 

 Based on our analysis, we believe that actual emissions 

approximate emissions allowable under the MACT standard. 

Therefore, the risk results for MACT-allowable emissions are 

approximately equal to those for actual emissions. For more 

detail about the estimate of the ratio of actual to MACTallowable emissions, see the memo in the docket for this action 

describing the estimation of MACT-allowable emission levels and 

associated risks and impacts. 

 There were no reported emissions of PB–HAP; therefore, we 

do not expect potential for human health multipathway risks or 

adverse environmental impacts. 

 Table B.1.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels. 

Table B.1.2. Epichlorohydrin Elastomers Production FacilityWide Risk Assessment Results

Maximum facility-wide individual cancer risk (in 1 

million) 10 

Epichlorohydrin Elastomer Production source 

category contribution to this maximum 

facility-wide individual cancer risk1

100% 

Maximum facility-wide chronic non-cancer TOSHI 0.1 

Epichlorohydrin Elastomer Production source 

category contribution to this maximum 

facility-wide non-cancer TOSHI1

100% 
Page 146 of 387 

1

 Percentage shown reflects Epichlorohydrin Elastomer Production source 

category contribution to the maximum facility-wide risks at the facility with 

the maximum risk value shown. 

 As shown in Table B.1.2, the maximum individual cancer risk 

from all HAP emissions at the one facility that contains 

epichlorohydrin elastomers production processes subject to the 

Group I Polymers and Resins MACT standard is estimated to be 10-

in-1 million, and the maximum chronic non-cancer TOSHI value is 

estimated to be 0.1. The estimated proportion of the risk 

attributable to Epichlorohydrin Elastomers Production source 

category processes at this facility is approximately 100 percent 

for cancer risks and 100 percent for chronic non-cancer risk. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on actual emissions levels for the population living 

within 5 km of the facilities, among various demographic groups 

are provided in a report available in the docket for this action 

and summarized in Table B.1.3 below. 

Table B.1.3. Epichlorohydrin Elastomers Demographic Risk 

Analysis Results

Population With Risk Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) Total 

(millions) Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 10 0.0008 54 53 1 1 0.4 20 11 

Facilitywide 10 0.01 52 50 2 1 0.2 23 14 
Page 147 of 387 

 The results of the demographic analysis show that, for the 

Epichlorohydrin Elastomers Production source category, of the 

population of 800 people with cancer risk greater than 1-in-1 

million, 54 percent could be classified as a “Minority,” 53 

percent are included the “African-American” demographic group, 

and 20 percent are included the “Below Poverty Level,” 

demographic group. The percentage of the population within 5 km 

of a epichlorohydrin elastomers production facility and with a 

cancer risk greater than 1-in-1 million is higher than expected 

for these demographic categories based on the typical 

distribution of these demographic groups across the United 

States. The table also shows that the results of the 

demographic analysis for the facility-wide emissions are similar 

to the results for the source category. 

 Details of these assessments and analyses can be found in 

the residual risk documentation as referenced in section IV.A. 

of this preamble, which is available in the docket for this 

action. 

d. What are our proposed decisions on risk acceptability and 

ample margin of safety? 

 October 2008 Proposed Decision. In our October 10, 2008, 

proposal, we proposed that the risks 0f 30-in-1 million were 

acceptable because the risks results indicated that cancer risks 
Page 148 of 387 

to the individual most exposed to emissions from the category 

were greater than 1-in-1 million, but less than 100-in-1 

million. We then analyzed other risk factors in the ample 

margin of safety determination. In this analysis, we proposed 

that emissions from the source category posed no potential for 

an adverse environmental effect, did not pose potential for 

human health multipathway risks, and were unlikely to cause 

acute or chronic non-cancer health impacts. We also identified 

one emissions control option that would reduce risks. We 

proposed that such control was not necessary to protect public 

health with an ample margin of safety in light of the high cost 

and limited addition health protection it would provide. 

Therefore, we proposed that the existing standard provided an 

ample margin of safety and proposed to re-adopt the existing 

MACT standard to satisfy section 112(f) of the CAA. 

 Risk Acceptability. The revised risk analysis we performed 

for this proposal indicates that the cancer risks to the 

individual most exposed is 10-in-1 million based on both actual 

and MACT-allowable emissions. The cancer incidence and the 

number of people exposed to cancer risks of 1-in-1 million or 

greater are not significantly changed from the risk identified 

in the October 2008 proposal. Similarly, the risk analysis 

continued to show no potential for an adverse environmental 

effect or human health multipathway effects, and that acute or 
Page 149 of 387 

chronic non-cancer health impacts are unlikely. Our additional 

analysis of facility-wide risks showed that the maximum 

facility-wide cancer risk is 10-in-1 million and that the 

maximum chronic non-cancer risks are unlikely to cause health 

impacts. Our additional analysis of the demographics of the 

exposed population shows disparities in risks between 

demographic groups for the 800 people exposed at risks of 1-in-1 

million. Based on this low cancer risk level and in 

consideration of other health measures and factors, including 

the low cancer incidence (one case in every 10,000 years) and 

the low maximum non-cancer risk level (TOSHI of 0.1), we propose 

that the risks from the Epichlorohydrin Elastomers Production 

are acceptable. 

 Ample Margin of Safety. Because we are proposing that the 

risks are acceptable, but still above 1-in-1 million, we then 

reconsidered our 2008 ample margin of safety decision. We have 

not identified any additional control options or any changes to 

the previously analyzed control option. Our analysis does not 

indicate a change in the emissions reductions that could be 

achieved or the cost of control for the control option 

considered in the October 2008 proposal. Therefore, we continue 

to propose that the current MACT standard provides an ample 

margin of safety to protect public health and the environment, 
Page 150 of 387 

and we are proposing to re-adopt the existing MACT standard to 

satisfy section 112(f) of the CAA. 

e. What are our proposed decisions on the technology review?

 In the October 10, 2008 proposal, we identified no 

advancements in practices, processes, and control technologies 

applicable to the emission sources in the Group I Polymers and 

Resins Production source categories in our technology review, 

and we proposed to re-adopt the existing MACT standard to 

satisfy section 112(d)(6) of the CAA. In that review, we 

examined the regulatory requirements and/or technical analyses 

for subsequently promulgated air toxics regulations with similar 

types of emissions sources as those in the Group I Polymers and 

Resins Production source categories, and we conducted a search 

of the RBLC for controls for VOC- and HAP-emitting processes in 

the Group I Polymers and Resins Production source categories. 

We have not identified any additional developments in practices, 

processes, and control technologies since the proposal date for 

the Epichlorohydrin Elastomers Production source category. 

Thus, we are proposing that it is not necessary to revise the 

MACT standard pursuant to section 112(d)(6) of the CAA. 

f. What other actions are we proposing?

SSM Provisions. We are proposing to eliminate the SSM 

exemption in the Group 1 Polymers and Resins MACT standard. 

Consistent with Sierra Club v. EPA, EPA is proposing that 
Page 151 of 387 

standards in this rule would apply at all times. We are 

proposing several revisions to 40 CFR part 63, subpart U. 

Specifically, we are proposing to revise Table 1 to indicate 

that the requirements of 40 CFR 63.6(e) of the General 

Provisions do not apply. The 40 CFR 63.6(e) requires owner or 

operators to act according to the general duty to “operate and 

maintain any affected source, including associated air pollution 

control equipment and monitoring equipment, in a manner 

consistent with safety and good air pollution control practices 

for minimizing emissions.” We are separately proposing to 

incorporate this general duty to minimize into 40 CFR 63.483(a). 

The 40 CFR 63.6(e) also requires the owner or operator of an 

affected source to develop a written SSM plan. We are proposing 

to remove the SSM plan requirement. We are proposing to remove 

the explanation of applicability of emissions standards during 

periods SSM in 40 CFR 63.480(j); remove the malfunction plan 

from 40 CFR 63.482 and revise the definition of initial start-up 

to remove references to malfunctions in this section; clarify 

that representative conditions do not include periods of SSM 

throughout the rule; remove references to periods of SSM in 

monitoring; and revise the SSM-associated recordkeeping and 

reporting requirements in 40 CFR 63.506 to require reporting and 

recordkeeping for periods of malfunction. We are also proposing 

to revise Table 1 to indicate that SSM-related provisions in 40 
Page 152 of 387 

CFR 63.6(f)(1), 40 CFR 63.7(e)(1), and 40 CFR 63.10(d)(5)(i) of 

the General Provisions do not apply. In addition, we are 

proposing to promulgate an affirmative defense against civil 

penalties for exceedances of emission standards caused by 

malfunctions, as well as criteria for establishing the 

affirmative defense. 

EPA has attempted to ensure that we have not incorporated 

into proposed regulatory language any provisions that are 

inappropriate, unnecessary, or redundant in the absence of the 

SSM exemption. We are specifically seeking comment on whether 

there are any such provisions that we have inadvertently 

incorporated or overlooked. 

 Significant Emission Points Not Previously Regulated 

Review. We identified the absence of a limit for a significant 

emissions source within the provisions of the Group I Polymers 

and Resins MACT standard that apply to the Epichlorohydrin 

Elastomers Production source category. Specifically, there are 

no back-end process operation emission limits for this source 

category.43 As these processes are major sources of emissions 

for the one facility in the source category, we are proposing to 

set standards for back-end process operations under CAA section 

112(d)(2) and (d)(3) in this action. 

 

43 Note that these uncontrolled emissions were included in the baseline 

risk assessment. 
Page 153 of 387 

 As there is only one facility in the source category, the 

emissions level currently being achieved by this facility 

represents the MACT floor. The annual HAP emissions from the 

back-end process operations at this facility are approximately 

36 TPY of toluene. There are two separate dryer vents, one 

emitting around 24 TPY of toluene, and the other emitting around 

12 TPY of toluene. Neither of these vents is controlled. 

Therefore, we have determined that the MACT floor for these 

processes is 36 TPY based on the current level of HAP stripping 

and recovery, given current production levels, but which would 

fluctuate proportionally with an increase or decrease in 

production levels. 

 As part of our beyond-the-floor analysis, we considered 

alternatives more stringent than the MACT floor option. We 

identified one option using add-on emission controls that would 

require the ducting of emissions from the back-end process 

operations to a control device, such as an incinerator. This 

option would also require an initial performance test of the 

incinerator and continuous parameter monitoring averaged daily. 

The capital costs of this option are estimated to be 

approximately $600,000 and the total annual costs are estimated 

to be approximately $1,100,000. We estimate that an incinerator 

would achieve an emissions reduction of 98 percent, resulting in 

a HAP decrease of approximately 35 TPY, with a cost- 
Page 154 of 387 

effectiveness of approximately $31,000/ton. Table B.2.4 

summarizes the cost and emission reduction impacts of the 

proposed options. Because the reduction in HAP would be due to 

toluene, no reduction of cancer risk would result from this 

control option. 

Table B.1.4. Epichlorohydrin Elastomer Production Facility 

Back-End Options Impacts

Cost-effectiveness 

as Compared to 

Baseline 

Regulatory 

Alternatives 

HAP 

Emissions 

(TPY HAP) 

Capital 

 Cost 

($million)

Annual 

 Cost 

($million/yr) $/Ton HAP Removed 

Baseline 36 -- -- -- 

1 (MACT floor) 36 0 0 -- 

2 (Beyond-the-floor) 1 0.6 1.1 31,000 

 In addition to the cost and emission reduction impacts 

shown in Table B.1.4, we estimate that the beyond-the-floor 

option would result in increases in criteria pollutant and 

carbon dioxide emissions (PM – 0.2 TPY, SO2 – 0.03 TPY, NOx – 

12 TPY, CO – 2 TPY, and CO2 – 7,000 TPY), and an increase in 

energy use of approximately 117,000 million British thermal 

units (BTU)/year at a cost of approximately $33,000/year. 

 We believe that the costs and other impacts of this beyondthe-floor option are not reasonable, given the level of emission 

reduction. Therefore, we are proposing an emission standard 

that reflects the MACT floor option. We are requesting comment 

on this analysis and these options. 
Page 155 of 387 

 As noted above, we are proposing that the MACT standard, 

prior to the implementation of the proposed emission limitation 

to the back-end process operations discussed in this section, 

provides an ample margin of safety to protect public health. 

Therefore, we maintain that after the new standard’s 

implementation, the rule will continue to provide an ample 

margin of safety to protect public health. Consequently, we do 

not believe it will be necessary to conduct another residual 

risk review under CAA section 112(f) for this source category 8 

years following promulgation of new back-end process 

limitations, merely due to the addition of this new MACT 

requirement. 

2. Polybutadiene Rubber Production. 

Polybutadiene Rubber Production is one of the source 

categories for which we proposed RTR decisions on October 10, 

2008. 

a. Overview of the source category.

Polybutadiene rubber is a homopolymer of 1,3-butadiene 

(i.e., 1,3-butadiene is the only monomer used in the production 

of this polymer). While both the solution and emulsion 

polymerization processes can be used to produce polybutadiene 

rubber, all currently operating facilities in the United States 

use a solution process. In the solution process, the reaction 

is conducted in an organic solvent (hexane, toluene, or a non-
Page 156 of 387 

HAP organic solvent), which helps to dissipate heat generated by 

the reaction and control the reaction rate. While polybutadiene 

rubber is the primary product at these facilities, styrenebutadiene rubber can also be produced as a minor product by 

adding styrene as a monomer. Most of the polybutadiene rubber 

manufactured in the United States is used in the production of 

tires in the construction of the tread and sidewalls. 

Polybutadiene rubber is also used as a modifier in the 

production of other polymers and resins (e.g., polystyrene). 

We identified five currently operating polybutadiene rubber 

production facilities subject to the Polymers and Resins I MACT 

standard. Some of these facilities are located at plant sites 

that also have other HAP-emitting sources regulated under 

separate MACT standards, which have been or will be addressed in 

separate regulatory actions. Three of the polybutadiene rubber 

production facilities use hexane as the solvent in their 

solution process, one facility uses toluene as its solvent, and 

the fifth uses a non-HAP organic solvent. Overall, hexane and 

toluene account for the majority of the HAP emissions from this 

source category (approximately 1,600 TPY hexane, which 

represents 70 percent of the total HAP emissions by mass, and 

500 TPY toluene, which represents 23 percent). The facilities 

in this source category also reported emissions of styrene, 1,3-

butadiene, ethylbenzene, and relatively minor quantities of 
Page 157 of 387 

other HAP. The majority of HAP emissions are from back-end 

process operations (approximately 70 percent of the total HAP by 

mass). For all emission sources except the back-end process 

operations, the actual emissions level is representative of the 

MACT-allowable level. For back-end process operations, we 

estimate that MACT-allowable emissions from this source category 

could be as high as seven times the actual emissions. Because 

these back-end limitations are production-based, this estimate 

was made by comparing the actual emissions levels to the 

emissions calculated using the limitations and production 

levels. For more detail about the estimate of the ratio of 

actual to MACT-allowable emissions, see the memo in the docket 

for this action describing the estimation of MACT-allowable 

emission levels and associated risks and impacts. 

b. What data were used in our risk analyses?

We initially created a preliminary data set for the 

Polybutadiene Rubber Production source category using 

information we collected directly from industry on emissions 

data and emissions release characteristics. We also reviewed 

the emissions and other data to identify data anomalies that 

could affect risk estimates. On March 29, 2007, we published an 

ANPRM (72 FR 29287) for the express purpose of requesting 

comments on, and updates to, this data set, as well as to the 

data sets for the other source categories addressed in that 
Page 158 of 387 

ANPRM. Comments received in response to the ANPRM were reviewed 

and considered. We made adjustments to the data set where we 

concluded the comments supported such adjustment. After making 

appropriate changes to the data set based on this public data 

review process, the data set on which we based the initial 

proposal was created. This data set was used to conduct the 

risk assessment and other analyses for the Polybutadiene Rubber 

Production source category that formed the basis for the 

proposed actions included in the October 10, 2008, proposal. We 

have continued to scrutinize the data set and any additional 

data that have become available since the October 10, 2008, 

proposal. 

c. What are the results of the risk assessments and analyses?

 We have conducted a revised inhalation risk assessment for 

the Polybutadiene Rubber Production source category. We have 

also conducted an assessment of facility-wide risk and performed 

a demographic analysis of population risks. Table B.2.1 

provides an overall summary of the results of the revised 

inhalation risk assessment. 

Table B.2.1. Polybutadiene Rubber Revised Inhalation Risk 

Assessment Results*

Maximum 

Individual 

Cancer Risk 

(in 1 million)2

Maximum 

Chronic Non-cancer 

TOSHI3

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population 

at Risk ≥

1-in-1 

Million 

Annual 

Cancer 

Incidence 

(cases 

per year) 

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum 

Offsite 

Acute 

Noncancer 

HQ4
Page 159 of 387 

5 30 30 24,000 0.003 0.3 0.3 HQREL = 1 

toluene * All results are for impacts out to 50 km from every source in the category. 

1

 Number of facilities evaluated in the risk analysis. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the 

Polybutadiene Rubber Production source category is the reproductive system. 

4

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

shown use the lowest available acute threshold value, which, in most cases, 

is the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section IV.A. of this preamble for 

explanation of acute threshold values. 

 The inhalation risk modeling was performed using actual 

emissions level data. As shown in Table B.2.1, the results of 

the revised inhalation risk assessment indicated the maximum 

lifetime individual cancer risk could be as high as 30-in-1 

million, the maximum chronic non-cancer TOSHI value could be up 

to 0.3, and the maximum off-facility-site acute HQ value could 

be as high as 1, based on the actual emissions level and the REL 

value for toluene. The total estimated national cancer 

incidence from these facilities based on actual emission levels 

is 0.003 excess cancer cases per year, or one case in every 333 

years. 

 Our analysis of potential differences between actual 

emission levels and emissions allowable under the MACT standard 

indicated that MACT-allowable emission levels are equal to 

actual emissions for all emissions sources other than back-end 

process operations and may be up to seven times greater than 

actual emission levels for back-end process operations. When 

these ratios of actual to MACT-allowable emissions are applied 
Page 160 of 387 

to each emission source type, the result is that the cancer 

risks at the MACT-allowable level are equal to those at the 

actual level shown in Table B.2.1. 

 There were no reported emissions of PB–HAP; therefore, we 

do not expect potential for human health multipathway risks or 

adverse environmental impacts. 

 Table B.2.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels. 

Table B.2.2. Polybutadiene Rubber Production Facility-Wide Risk 

Assessment Results

Maximum facility-wide individual cancer risk (in 1 

million) 30 

Polybutadiene Rubber Production source 

category contribution to this maximum 

facility-wide individual cancer risk1

100% 

Maximum facility-wide chronic non-cancer TOSHI 0.3 

Polybutadiene Rubber Production source 

category contribution to this maximum 

facility-wide non-cancer TOSHI1

100% 

1

 Percentage shown reflects Polybutadiene Rubber Production source category 

contribution to the maximum facility-wide risks at the facility with the 

maximum risk value shown. 

The maximum individual cancer risk from all HAP emissions at a 

facility that contains polybutadiene rubber production processes 

subject to the Group I Polymers and Resins MACT standard is 

estimated to be 30-in-1 million, and the maximum chronic noncancer TOSHI value is estimated to be 0.3. At the facilities 

where these maximum risk values occur, the estimated proportion 

of the risk attributable to the Polybutadiene Rubber Production 
Page 161 of 387 

source category processes is 100 percent for both cancer and 

non-cancer risk. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on actual emissions levels for the population living 

within 5 km of the facilities, among various demographic groups 

are provided in a report available in the docket for this action 

and summarized in Table B.2.3 below. 

Table B.2.3. Polybutadiene Rubber Demographic Risk Analysis 

Results

Population With Risk Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) Total 

(millions) Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 30 0.017 11 6 4 4 0.5 11 13 

Facilitywide 30 0.02 12 7 5 4 0.5 12 14 

 The results of the Polybutadiene Rubber Production source 

category demographic analysis show that the percentage of the 

population within 5 km of a polybutadiene rubber production 

facility and with a cancer risk greater than 1-in-1 million is 

less than the distribution of these demographic groups across 

the United States as displayed in Table B.2.3, with the 

exception of those “Over 25 Without a High School Diploma”, 

where the levels are equal to the distribution of these 
Page 162 of 387 

demographic groups across the United States. The table also 

shows that the facility-wide emissions demographic analysis 

shows similar results. 

 Details of these assessments and analyses can be found in 

the residual risk documentation as referenced in section IV.A 

of this preamble, which is available in the docket for this 

action. 

d. What are our proposed decisions on risk acceptability and 

ample margin of safety?

 October 2008 Proposed Decision. In our October 10, 2008 

proposal, we proposed that the risks were acceptable because the 

risks results indicated that cancer risks to the individual most 

exposed to emissions from the category were 10-in-1 million 

which is greater than 1-in-1 million but less than 100-in-1 

million. We then analyzed other risk factors in the ample 

margin of safety determination. In this analysis, we proposed 

that emissions from the source category posed no potential for 

an adverse environmental effect, did not pose potential for 

human health multipathway risks, and were unlikely to cause 

acute or chronic non-cancer health impacts. We also identified 

two emissions control options that would reduce risks. We 

proposed that these controls were not necessary to protect 

public health with an ample margin of safety in light of the 

high cost and limited addition health protection they would 
Page 163 of 387 

provide. Therefore, we proposed that the existing standard 

provided an ample margin of safety and proposed to re-adopt the 

existing MACT standard to satisfy section 112(f) of the CAA. 

 Risk Acceptability. The revised risk analysis we performed 

for this proposal indicates that the cancer risks to the 

individual most exposed is 30-in-1 million based on both actual 

and MACT-allowable emissions. The cancer incidence and the 

number of people exposed to cancer risks of 1-in-1 million or 

greater are not significantly changed from the risk identified 

in the October 2008 proposal. Similarly, the risk analysis 

continued to show no potential for an adverse environmental 

effect or human health multipathway effects, and that chronic 

non-cancer health impacts are unlikely. The revised assessment 

did indicate that an acute non-cancer HQ as high as 1 could 

occur, based on the REL value at an area adjacent to the 

facility fenceline. Our additional analysis of facility-wide 

risks showed that the maximum facility-wide cancer risk is 30-

in-1 million and that the maximum chronic non-cancer risks are 

unlikely to cause health impacts. Our additional analysis of 

the demographics of the exposed population suggests there are no 

disparities in risks for the various demographic groups. Based 

on this low cancer risk level and in consideration of other 

health measures and factors, including the low cancer incidence 

(one case in every 333 years) and the low maximum non-cancer 
Page 164 of 387 

risk level (TOSHI of 0.3), we propose that the risks from the 

Polybutadiene Rubber Production source category are acceptable. 

 Ample Margin of Safety. Because we are proposing that the 

risks are acceptable, but still above 1-in-1 million, we then 

re-considered our 2008 ample margin of safety decision. We have 

not identified any additional control options or any changes to 

the previously analyzed control option. Our analysis does not 

indicate a change in the emissions reductions that could be 

achieved or the cost of control for the control option 

considered in the October 2008 proposal. Therefore, we continue 

to propose that the current MACT standard provides an ample 

margin of safety to protect public health and the environment, 

and we are proposing to re-adopt the existing MACT standard to 

satisfy section 112(f) of the CAA. 

e. What are our proposed decisions on the technology review?

 In the October 10, 2008 proposal, we identified no 

advancements in practices, processes, and control technologies 

applicable to the emission sources in the Group I Polymers and 

Resins Production source categories in our technology review, 

and we proposed to re-adopt the existing MACT standard to 

satisfy section 112(d)(6) of the CAA. In that review we 

examined the regulatory requirements and/or technical analyses 

for subsequently promulgated air toxics regulations with similar 

types of emissions sources as those in the Group I Polymers and 
Page 165 of 387 

Resins Production source categories, and we conducted a search 

of the RBLC for controls for VOC- and HAP-emitting processes in 

the Group I Polymers and Resins Production source categories. 

We have not identified any additional developments in practices, 

processes, and control technologies since the proposal date for 

the Polybutadiene Rubber Production source category. In 

addition, we have not identified the need for revisions of the 

standards to correct editorial errors, make clarifications, or 

address issues with implementation or determining compliance 

with the rule provisions. Thus, we are continuing to propose to 

re-adopt the existing MACT standard to satisfy section 112(d)(6) 

of the CAA. 

f. What other actions are we proposing?

The proposed changes to the SSM provisions for the Group I 

Polymers and Resins MACT, which apply to the Polybutadiene 

Rubber Production source category, are discussed above in 

section V.B.1.f. 

3. Styrene Butadiene Rubber and Latex Production. 

 Styrene Butadiene Rubber and Latex Production is one of the 

source categories for which we proposed RTR decisions on October 

10, 2008. 

a. Overview of the source category. 

Styrene butadiene rubber and latex are elastomers prepared 

from styrene and butadiene monomer units. The source category 
Page 166 of 387 

is divided into three subcategories due to technical process and 

HAP emission differences: (1) The production of styrene 

butadiene rubber by emulsion, (2) the production of styrene 

butadiene rubber by solution, and (3) the production of styrene 

butadiene latex. Styrene butadiene rubber is coagulated and 

dried to produce a solid product, while latex is a liquid 

product. For both styrene butadiene rubber processes, the 

monomers used are styrene and butadiene; either process can be 

conducted as a batch or a continuous process. These elastomers 

are commonly used in tires and tire-related products. 

We identified three currently operating styrene butadiene rubber 

production facilities using the emulsion process and three 

styrene butadiene rubber latex production facilities subject to 

the Polymers and Resins I MACT standard. Other than the 

polybutadiene plants that produce styrene butadiene rubber as a 

minor product, we did not identify any styrene butadiene rubber 

produced in a solution process. Some of these facilities are 

located at plant sites that also have other HAP-emitting sources 

regulated under separate MACT standards, for which we have 

addressed or will address in future rulemaking actions. 

Overall, styrene accounts for the majority of the HAP emissions 

from these facilities (approximately 276 TPY and 90 percent of 

the total HAP emissions by mass). These facilities also 

reported relatively small emissions of other HAP. The majority 
Page 167 of 387 

of HAP emissions are from back-end process operations 

(approximately 78 percent of the total HAP by mass). For all 

emission sources except the back-end process operations, the 

actual emissions level is representative of the MACT-allowable 

level. For back-end process operations, we estimate that MACTallowable emissions from this source category could be as high 

as four times the actual emissions. Since these back-end 

limitations are production-based, this estimate was made by 

comparing the actual emissions levels to the emissions 

calculated using the limitations and production levels. For 

more detail about the estimate of the ratio of actual to MACTallowable emissions, see the memo in the docket for this action 

describing the estimation of MACT-allowable emission levels and 

associated risks and impacts. 

b. What data were used in our risk analyses?

We initially created a preliminary data set for the Styrene 

Butadiene Rubber and Latex Production source category using 

information we collected directly from industry on emissions 

data and emissions release characteristics. We also reviewed 

the emissions and other data to identify data anomalies that 

could affect risk estimates. On March 29, 2007, we published an 

ANPRM (72 FR 29287) for the express purpose of requesting 

comments on and updates to this data set, as well as to the data 

sets for the other source categories addressed in that ANPRM. 
Page 168 of 387 

Comments received in response to the ANPRM were reviewed and 

considered, and we made adjustments to the data set where we 

concluded the comments supported such adjustment. After making 

appropriate changes to the data set based on this public data 

review process, the data set on which we based the initial 

proposal was created. This data set was used to conduct the 

risk assessment and other analyses for the Styrene Butadiene 

Rubber and Latex Production source category, which formed the 

basis for the proposed RTR actions included in the October 10, 

2008 proposal. 

We have continued to scrutinize the existing data set and 

have evaluated any additional data that became available 

subsequent to the October 2008 proposal. Specific questions we 

had concerning current operations led us to develop a 

questionnaire and ask for updated emissions and emissions 

release characteristics information. This information was 

requested from the facilities in May 2010 using the authority of 

section 114 of the CAA. We updated our data set for this source 

category based on the information received through this request. 

c. What are the results of the risk assessments and analyses?

 We have conducted a revised inhalation risk assessment for 

the Styrene Butadiene Rubber and Latex Production source 

category. We have also conducted an assessment of facility-wide 

risk and performed a demographic analysis of population risks. 
Page 169 of 387 

Table B.3.1 provides an overall summary of the results of the 

revised inhalation risk assessment. 

Table B.3.1. Styrene Butadiene Rubber and Latex Production 

Revised Inhalation Risk Assessment Results* 

Maximum 

Individual 

Cancer Risk 

(in 1 million)2

Maximum 

Chronic Non-cancer 

TOSHI3

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population 

at Risk ≥

1-in-1 

Million 

Annual 

Cancer 

Incidence 

(cases 

per year) 

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum 

Offsite 

Acute 

Noncancer 

HQ4

6 10 10 25,000 0.004 0.2 0.2 

HQREL = 

0.4 

styrene * All results are for impacts out to 50 km from every source in the category. 

1

 Number of facilities evaluated in the risk analysis. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the Styrene 

Butadiene Rubber and Latex Production source category is the reproductive 

system. 

4

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

shown use the lowest available acute threshold value, which, in most cases, 

is the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section IV.A. of this preamble for 

explanation of acute threshold values. 

 The inhalation risk modeling was performed using actual 

emissions level data. As shown in Table B.3.1, the results of 

the revised inhalation risk assessment indicated the maximum 

lifetime individual cancer risk could be as high as 10-in-1 

million, the maximum chronic non-cancer TOSHI value could be up 

to 0.2, and the maximum off-facility-site acute HQ value could 

be as high as 0.4, based on the actual emissions level and the 

REL value for styrene. The total estimated national cancer 

incidence from these facilities based on actual emission levels 

is 0.004 excess cancer cases per year, or one case in every 250 

years. 
Page 170 of 387 

 Our analysis of potential differences between actual 

emission levels and emissions allowable under the MACT standard 

indicated that MACT-allowable emission levels are equal to 

actual emissions for all emissions sources other than back-end 

process operations. While the emissions may be up to four times 

greater than actual emission levels for back-end process 

operations, the compounds emitted do not have cancer potency 

values so this potential increase in emissions does not effect 

risk. When these ratios of actual to MACT-allowable emissions 

are applied to each emission source type, the result is that the 

cancer risks at the MACT-allowable level are equal to those at 

the actual level shown in Table B.3.1. 

 There were no reported emissions of PB–HAP; therefore, we 

do not expect potential for human health multipathway risks or 

adverse environmental impacts. 

 Table B.3.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels. 

Table B.3.2. Styrene Butadiene Rubber and Latex Production 

Facility-Wide Risk Assessment Results

Maximum facility-wide individual cancer risk (in 1 

million) 70 

Styrene Butadiene Rubber and Latex Production 

source category contribution to this maximum 

facility-wide individual cancer risk1

5% 

Maximum facility-wide chronic non-cancer TOSHI 1 

Styrene Butadiene Rubber and Latex Production 

source category contribution to this maximum 

facility-wide non-cancer TOSHI1

10% 
Page 171 of 387 

1

 Percentage shown reflects the Styrene Butadiene Rubber Production source 

category contribution to the maximum facility-wide risks at the facility with 

the maximum risk value shown. 

 As shown in Table B.3.2, the maximum individual cancer risk 

from all HAP emissions at a facility that contains styrene 

butadiene rubber and latex production processes subject to the 

Group I Polymers and Resins MACT standard is estimated to be 70-

in-1 million, and the maximum chronic non-cancer TOSHI value is 

estimated to be 1. At the facilities where these maximum risk 

values occur, the estimated proportion of the risk attributable 

to Styrene Butadiene Rubber and Latex Production source category 

processes is approximately 5 percent for cancer risks and 10 

percent for chronic non-cancer risk. Both the cancer and noncancer risks at this facility are primarily due to a nitrile 

butadiene rubber process, which has recently closed. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on actual emissions levels for the population living 

within 5 km of the facilities, among various demographic groups 

are provided in a report available in the docket for this action 

and summarized in Table B.3.3 below. 

Table B.3.3. Styrene Butadiene Rubber and Latex Production 

Demographic Risk Analysis Results

Population With Risk Greater Than 1-in-1 million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) Total 

(millions) Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 
Page 172 of 387 

Nationwide n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 10 0.02 40 3 36 54 0.6 18 24 

Facilitywide 70 0.1 50 29 20 32 0.5 23 20 

 The results of the Styrene Butadiene Rubber and Latex 

Production source category demographic analysis show that of the 

population with cancer risk greater than 1-in-1 million, 40 

percent could be classified as a “Minority,” 54 percent are 

included in the “Hispanic or Latino” demographic group, 36 

percent are included in the “Other and Multiracial,” demographic 

group, 18 percent are included in the “Below Poverty Level,” and 

24 percent are included in the “Over 25 Without a High School 

Diploma” demographic group. These percentages of the population 

within 5 km of a styrene butadiene rubber and latex production 

facility and with a cancer risk greater than 1-in-1 million is 

higher than the percentages for these demographic categories 

based on the distribution of these demographic groups across the 

United States. The table also shows that the results of the 

facility-wide demographic analysis are higher than the national 

percentages for the those that could be classified as a 

“Minority” and for those included in the “Hispanic or Latino,” 

“African American,” “Other and Multiracial,” “Below Poverty 

Level,” and the “Over 25 Without a High School Diploma” 

demographic groups. 
Page 173 of 387 

 Details of these assessments and analyses can be found in 

the residual risk documentation as referenced in section IV.A of 

this preamble, which is available in the docket for this action. 

d. What are our proposed decisions on risk acceptability and 

ample margin of safety?

 October 2008 Proposed Decision. In our October 10, 2008 

proposal, we proposed that the risks were acceptable because the 

risks results of 7-in-1 million indicated that cancer risks to 

the individual most exposed to emissions from the category were 

greater than 1-in-1 million but less than 100-in-1 million. We 

then analyzed other risk factors in the ample margin of safety 

determination. In this analysis, we proposed that emissions 

from the source category posed no potential for an adverse 

environmental effect, did not pose potential for human health 

multipathway risks, and were unlikely to cause acute or chronic 

non-cancer health impacts. We also identified one emissions 

control option that would reduce risks. We proposed that such 

control was not necessary to protect public health with an ample 

margin of safety in light of the high cost and limited addition 

health protection it would provide. Therefore, we proposed that 

the existing standard provided an ample margin of safety and 

proposed to re-adopt the existing MACT standard to satisfy 

section 112(f) of the CAA. 
Page 174 of 387 

 Risk Acceptability. The revised risk analysis we performed 

for this proposal indicates that the cancer risks to the 

individual most exposed is 10-in-1 million based on both actual 

and MACT-allowable emissions. The cancer incidence and the 

number of people exposed to cancer risks of 1-in-1 million or 

greater are not significantly changed from the risk identified 

in the October 2008 proposal. Similarly, the risk analysis 

continued to show no potential for an adverse environmental 

effect or human health multipathway effects, and that chronic 

non-cancer health impacts are unlikely. The revised assessment 

indicated that an acute non-cancer HQ as high as 0.4 could 

occur, based on the REL value. Our additional analysis of 

facility-wide risks showed that the maximum facility-wide cancer 

risk is 70-in-1 million and the maximum facility-wide non-cancer 

TOSHI is 1. It also showed that the styrene butadiene rubber 

production processes located at the facilities with these 

maximum risk values contribute approximately 5 and 10 percent to 

such risks, respectively. Our additional analysis of the 

demographics of the exposed population may show disparities in 

risks between demographic groups. Based on this low cancer risk 

level and in consideration of other health measures and factors, 

including the low cancer incidence (one case in every 250 years) 

and the low maximum non-cancer risk level (TOSHI of 0.2), we 
Page 175 of 387 

propose that the risks from the Styrene Butadiene Rubber and 

Latex Production source category are acceptable. 

 Ample Margin of Safety. Because we are proposing that the 

risks are acceptable, but still above 1-in-1 million, we then 

re-considered our 2008 ample margin of safety decision. 

 We have not identified any additional control options or 

any changes to the previously analyzed control option to reduce 

risks. Our analysis does not indicate a change in the emissions 

reductions that could be achieved or the cost of control for the 

control option considered in the October 2008 proposal. 

Therefore, we continue to propose that the current MACT standard 

provides an ample margin of safety to protect public health and 

the environment, and we are proposing to re-adopt the existing 

MACT standard to satisfy section 112(f) of the CAA. 

e. What are our proposed decisions on the technology review?

 In the October 10, 2008 proposal, we identified no 

advancements in practices, processes, and control technologies 

applicable to the emission sources in the Group I Polymers and 

Resins Production source categories in our technology review, 

and we proposed to re-adopt the existing MACT standard to 

satisfy section 112(d)(6) of the CAA. In that review we 

examined the regulatory requirements and/or technical analyses 

for subsequently promulgated air toxics regulations with similar 

types of emissions sources as those in the Group I Polymers and 
Page 176 of 387 

Resins I Production source categories, and we conducted a search 

of the RBLC for controls for VOC- and HAP-emitting processes in 

the Group I Polymers and Resins Production source categories. 

We have not identified any additional developments in practices, 

processes, and control technologies since the proposal date for 

the Styrene Butadiene Rubber and Latex Production source 

category. Thus, we are continuing to propose to re-adopt the 

existing MACT standard to satisfy section 112(d)(6) of the CAA. 

f. What other actions are we proposing?

The proposed changes to the SSM provisions for the Group I 

Polymers and Resins MACT, which apply to the Styrene Butadiene 

Rubber and Latex Production source category, are discussed above 

in section V.B.1.f. 

4. Nitrile Butadiene Rubber Production. 

Nitrile Butadiene Rubber Production is one of the source 

categories for which we proposed RTR decisions on October 10, 

2008. 

a. Overview of the source category. 

Nitrile butadiene rubber is a copolymer of 1,3-butadiene 

and acrylonitrile, and the Nitrile Butadiene Rubber Production 

source category includes any facility that polymerizes 1,3-

butadiene and acrylonitrile. While nitrile butadiene rubber is 

the primary product at these facilities, styrene-butadiene 

rubber can also be produced as a minor product by substituting 
Page 177 of 387 

styrene for acrylonitrile as a monomer. Depending on its 

specific composition, nitrile butadiene rubber can be resistant 

to oil and chemicals, a property that facilitates its use in 

disposable gloves, hoses, seals, and a variety of automotive 

applications. 

We identified one nitrile butadiene rubber production 

facility currently subject to the Polymers and Resins I MACT 

standard. This facility is at a plant site that also has other 

HAP-emitting sources that are regulated under separate MACT 

standards, for which we have addressed or will address in future 

rulemaking actions. Acrylonitrile and 1,3-butadiene account for 

the HAP emissions from this source category (approximately 2 

TPY). The majority of HAP emissions are from back-end process 

operations (approximately 97 percent of the total HAP by mass) 

for this source category. We estimate that MACT-allowable 

emissions from this source category are approximately equal to 

reported, actual emissions. For more detail about this estimate 

of the ratio of actual to MACT-allowable emissions, see the memo 

in the docket for this action describing the estimation of MACTallowable emission levels and associated risks and impacts. 

b. What data were used in our risk analyses?

We initially created a preliminary data set for the Nitrile 

Butadiene Rubber Production source category using information we 

collected directly from industry on emissions data and emissions 
Page 178 of 387 

release characteristics. We also reviewed the emissions and 

other data to identify data anomalies that could affect risk 

estimates. On March 29, 2007, we published an ANPRM (72 FR 

29287) for the express purpose of requesting comments and 

updates to this data set, as well as to the data sets for the 

other source categories addressed in that ANPRM. Comments 

received in response to the ANPRM were reviewed and considered, 

and we made adjustments to the data set where we concluded the 

comments supported such adjustment. After making appropriate 

changes to the data set based on this public data review 

process, the data set on which we based the initial proposal was 

created. This data set was used to conduct the risk assessment 

and other analyses for the Nitrile Butadiene Rubber Production 

source category, which formed the basis for the proposed RTR 

actions included in the October 10, 2008 proposal. 

Since the proposal, we have continued to scrutinize the 

existing data set and have evaluated any additional data that 

became available subsequent to the October 10, 2008 proposal. 

Specific questions we had concerning current operations led us 

to develop a questionnaire and ask for updated emissions and 

emissions release characteristics information. This information 

was requested from the facility in May 2010 using the authority 

of section 114 of the CAA. We updated our data set for this 
Page 179 of 387 

source category based on the information received through this 

request. 

c. What are the results of the risk assessments and analyses?

 We have conducted a revised inhalation risk assessment for 

the Nitrile Butadiene Rubber Production source category. We 

have also conducted an assessment of facility-wide risk and 

performed a demographic analysis of population risks. Table 

B.4.1 provides an overall summary of the results of the revised 

inhalation risk assessment. 

Table B.4.1. Nitrile Butadiene Rubber Production Revised 

Inhalation Risk Assessment Results* 

Maximum 

Individual 

Cancer Risk 

(in 1 million)2

Maximum 

Chronic Non-cancer 

TOSHI3

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population 

at Risk ≥

1-in-1 

Million 

Annual 

Cancer 

Incidence 

(cases 

per year) 

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum Offsite Acute 

Non-cancer 

HQ4

1 2 2 70 0.0004 0.009 0.009 

HQAEGL-1 = 

0.002 

acrylonitrile * All results are for impacts out to 50 km from every source in the category. 

1

 Number of facilities evaluated in the risk analysis. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the Nitrile 

Butadiene Rubber Production source category is the reproductive system. 4

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

shown use the lowest available acute threshold value, which in most cases, is 

the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section III.A of this preamble for 

explanation of acute threshold values. 

 The inhalation risk modeling was performed using actual 

emissions level data. As shown in Table B.4.1, the results of 

the revised inhalation risk assessment indicated the maximum 

lifetime individual cancer risk could be as high as 2-in-1 
Page 180 of 387 

million, the maximum chronic non-cancer TOSHI value could be up 

to 0.009, and the maximum off-facility-site acute HQ value could 

be as high as 0.002, based on the actual emissions level and the 

AEGL-1 value for acrylonitrile. The total estimated national 

cancer incidence from these facilities based on actual emission 

levels is 0.0004 excess cancer cases per year, or one case in 

every 2,500 years. 

 Our analysis of potential differences between actual 

emission levels and emissions allowable under the MACT standard 

indicate that actual and allowable emissions are approximately 

the same. Therefore, the risk results for MACT-allowable 

emissions are equal to those for actual emissions. 

 There were no reported emissions of PB–HAP; therefore, we 

do not expect potential for human health multipathway risks or 

adverse environmental impacts. 

 Table B.4.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels. 

Table B.4.2. Nitrile Butadiene Rubber Production Facility-Wide 

Risk Assessment Results

Maximum facility-wide individual cancer risk (in 1 

million) 5 

Nitrile Butadiene Rubber Production source 

category contribution to this maximum 

facility-wide individual cancer risk1

33% 

Maximum facility-wide chronic non-cancer TOSHI 0.03 

Nitrile Butadiene Rubber Production source 

category contribution to this maximum 

facility-wide non-cancer TOSHI1

30% 
Page 181 of 387 

1

 Percentage shown reflects Nitrile Butadiene Rubber Production source 

category contribution to the maximum facility-wide risks at the facility with 

the maximum risk value shown. 

The maximum individual cancer risk from all HAP emissions at a 

facility that contains nitrile butadiene rubber production 

processes subject to the Group I Polymers and Resins MACT 

standard is estimated to be 5-in-1 million, and the maximum 

chronic non-cancer TOSHI value is estimated to be 0.03. The 

estimated proportion of the risk attributable to Nitrile 

Butadiene Rubber Production source category processes at this 

facility is approximately 33 percent for cancer risks and 30 

percent for chronic non-cancer risk. This facility also has 

processes subject to the Group IV Polymers and Resins MACT 

standard, 40 CFR part 63, subpart JJJ. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on actual emissions levels for the population living 

within 5 km of the facilities, among various demographic groups 

are provided in a report available in the docket for this action 

and summarized in Table B.4.3 below. 

Table B.4.3. Nitrile Butadiene Rubber Production Demographic 

Risk Analysis Results

Population With Risk Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) Total 

(millions) Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 
Page 182 of 387 

Source 

Category 2 0.00007 94 94 0 0 0 33 14 

Facilitywide 5 0.006 95 93 2 0.4 0.1 23 17 

 The results of the demographic analysis show that, for the 

Nitrile Butadiene Rubber Production source category, of the 

population of 70 people with cancer risk greater than 1-in-1 

million, 94 percent could be classified as a “Minority,” 94 

percent are included the “African-American” demographic group, 

33 percent are included in the “Below Poverty Level” demographic 

group, and 14 percent are included in the “Over 25 Without a 

High School Diploma” demographic group. The percentage of the 

population for these demographic categories within 5 km of a 

nitrile butadiene rubber production facility and with a cancer 

risk greater than 1-in-1 million is higher than distribution of 

these demographic groups across the United States. The table 

also shows that the results of the demographic analysis for the 

6,000 people at cancer risk greater than 1-in-1 million from 

facility-wide emissions are similar to the results for the 

source category. 

 Details of these assessments and analyses can be found in 

the residual risk documentation as referenced in section IV.A of 

this preamble, which is available in the docket for this action. 

d. What are our proposed decisions on risk acceptability and 

ample margin of safety?
Page 183 of 387 

 October 2008 Proposed Decision. In our October 2008 

proposal, we proposed that the risks were acceptable because the 

risks results indicated that cancer risks to the individual most 

exposed to emissions from the category of 60-in-1 million were 

greater than 1-in-1 million but less than 100-in-1 million. We 

then analyzed other risk factors in the ample margin of safety 

determination. In this analysis, we proposed that emissions 

from the source category posed no potential for an adverse 

environmental effect, did not pose potential for human health 

multipathway risks, and were unlikely to cause acute or chronic 

non-cancer health impacts. We also identified one emissions 

control option that would reduce risks. We proposed that such 

control was not necessary to protect public health with an ample 

margin of safety in light of the high cost and limited addition 

health protection it would provide. Therefore, we proposed that 

the existing standard provided an ample margin of safety and 

proposed to re-adopt the existing MACT standard to satisfy 

section 112(f) of the CAA. 

 Risk Acceptability. The revised risk analysis we performed 

for this proposal indicates that the cancer risks to the 

individual most exposed is 2-in-1 million based on both actual 

and MACT-allowable emissions. The cancer incidence and the 

number of people exposed to cancer risks of 1-in-1 million or 

greater are much less than the risk identified in the October 
Page 184 of 387 

2008 proposal. Similarly, the risk analysis continued to show 

no potential for an adverse environmental effect or human health 

multipathway effects, and that acute or chronic non-cancer 

health impacts are unlikely. Our additional analysis of 

facility-wide risks showed that the maximum facility-wide cancer 

risk is 5-in-1 million and that the maximum chronic non-cancer 

risks are unlikely to cause health impacts. Our additional 

analysis of the demographics of the exposed population may show 

disparities in risks between demographic groups, but only for 

the 60 people at cancer risk greater than 1-in-1 million. Based 

on this low cancer risk level and in consideration of other 

health measures and factors, including the low cancer incidence 

(one case in every 2,500 years) and the low maximum non-cancer 

risk level (TOSHI of 0.009), we propose that the risks from the 

Nitrile Butadiene Rubber Production source category are 

acceptable. 

 Ample Margin of Safety. Because we are proposing that the 

risks are acceptable, but still above 1-in-1 million, we then 

re-considered our October 2008 ample margin of safety decision. 

 We have not identified any additional control options or 

any changes to the previously analyzed control option. Our 

analysis does not indicate a change in the emissions reductions 

that could be achieved or the cost of control for the control 

option considered in the October 2008 proposal. Therefore, we 
Page 185 of 387 

continue to propose that the current MACT standard provides an 

ample margin of safety to protect public health and the 

environment, and we are proposing to re-adopt the existing MACT 

standard to satisfy section 112(f) of the CAA. 

e. What are our proposed decisions on the technology review?

 In the October 10, 2008 proposal, we identified no 

advancements in practices, processes, and control technologies 

applicable to the emission sources in the Group I Polymers and 

Resins Production source categories in our technology review, 

and we proposed to re-adopt the existing MACT standard to 

satisfy section 112(d)(6) of the CAA. In that review we 

examined the regulatory requirements and/or technical analyses 

for subsequently promulgated air toxics regulations with similar 

types of emissions sources as those in the Group I Polymers and 

Resins Production source categories, and we conducted a search 

of the RBLC for controls for VOC- and HAP-emitting processes in 

the Group I Polymers and Resins Production source categories. 

We have not identified any additional developments in practices, 

processes, and control technologies since the proposal date for 

the Nitrile Butadiene Rubber Production source category. Thus, 

we are continuing to propose to re-adopt the existing MACT 

standard to satisfy section 112(d)(6) of the CAA. 

f. What other actions are we proposing?

SSM Provisions. The proposed changes to the Group I 
Page 186 of 387 

Polymers and Resins MACT, which apply to the Nitrile Butadiene 

Rubber Production source category, are discussed above in 

section V.B.1.f. 

 Significant Emission Points Not Previously Regulated. We 

identified the absence of a standard for a significant emissions 

source in the category in the provisions of the Group I Polymers 

and Resins MACT standard that apply to the Nitrile Butadiene 

Rubber Production source category. Specifically, there are no 

back-end process operation emission limits for this source 

category.44 As these processes are major sources of emissions 

for the one facility in the source category, we are proposing to 

set standards for back-end process operations under CAA section 

112(d)(2) and (d)(3) in this action. 

 The emission limit we are proposing today represents the 

MACT floor level of control. As there is only one facility in 

the source category, the emissions limitation achieved by this 

facility is the MACT floor. The annual emissions from the backend process operations at this facility are approximately 2 TPY. 

There are 11 separate dryer vents; one is controlled, while the 

others are uncontrolled. The controlled vent emits around 0.003 

TPY of 1,3-butadiene and 0.002 TPY of acrylonitrile. The 

regenerative thermal oxidizer used on this vent achieves 

 

44 Note that these uncontrolled emissions were included in the baseline 

risk assessment. 
Page 187 of 387 

approximately 96 percent control of the acrylonitrile emissions, 

but no control of 1,3-butadiene. The collection of 10 

uncontrolled vents emit around 0.8 TPY of 1,3-butadiene and 0.9 

TPY of acrylonitrile. 

 As part of our beyond-the-floor analysis, we considered 

alternatives more stringent than the MACT floor option. We 

identified one option using add-on emission controls that would 

require the ducting of emissions from the currently uncontrolled 

back-end process operations emission source to a control device, 

such as an incinerator. This option would also require an 

initial performance test of the incinerator and continuous 

parameter monitoring averaged daily. The capital costs of this 

option are estimated to be approximately $1,600,000 and the 

total annual costs are estimated to be approximately 

$11,400,000/year. We estimate that an incinerator would achieve 

an emissions reduction of 98 percent, resulting in a HAP 

decrease of approximately 1.7 TPY, with a cost-effectiveness of 

approximately $6,700,000/ton. Table B.4.4 summarizes the cost 

and emission reduction impacts of the proposed options. 

Table B.4.4. Nitrile Butadiene Rubber Production Facility BackEnd Option Impacts

Regulatory 

Alternatives 

HAP 

Emissions 

(TPY) 

Capital 

Cost 

(million $) 

Annual 

Cost 

(million $/yr) 

CostEffectiveness 

as Compared to 

Baseline 

(million $/ton 

HAP removed) 

Baseline 1.7 -- -- -- 
Page 188 of 387 

1 (MACT floor) 1.7 0 0 -- 

2 (Beyond-thefloor) 0.04 1.6 11.4 6.7 

 In addition to the cost and emission reduction impacts 

shown in Table B.4.4, we estimate that the beyond-the-floor 

option will result in increases in criteria pollutant and carbon 

dioxide emissions (PM – 2 TPY, SO2 – 0.4 TPY, NOx – 133 TPY, CO – 

23 TPY, and CO2 – 80,000 TPY) and an increase in energy use of 

approximately 1,400,000 million BTU/year at a cost of 

approximately $385,000/year. 

 We believe that the costs and other impacts of this beyondthe-floor option are not reasonable, given the level of emission 

reduction. Therefore, we are proposing Option 1, the MACT floor 

option. We are requesting comment on this analysis and these 

options. 

 As noted above, we are proposing that the MACT standard, 

prior to the implementation of the proposed emission limitation 

to the back-end process operations discussed in this section, 

provides an ample margin of safety to protect public health. 

Since the proposed emission limitation represents the existing 

level of control for the single plant in the source category, 

this proposed emission limitation will not have an impact on 

risk. Therefore, we maintain that after its implementation, the 

rule will continue to provide an ample margin of safety to 
Page 189 of 387 

protect public health. Consequently, we do not believe it will 

be necessary to conduct another residual risk review under CAA 

section 112(f) for this source category 8 years following 

promulgation of new back-end process limitations, merely due to 

the addition of this new MACT requirement. 

5. Neoprene Rubber Production. 

 Neoprene Rubber Production is one of the source categories 

for which we proposed and finalized RTR decisions on December 

12, 2007 (72 FR 70543) and December 16, 2008 (73 FR 76220), 

respectively. 

a. Overview of the source category. 

Neoprene is a polymer of chloroprene. Neoprene was 

originally developed as an oil-resistant substitute for natural 

rubber, and its properties allow its use in a wide variety of 

applications, including wetsuits, gaskets and seals, hoses and 

tubing, plumbing fixtures, adhesives, and other products. We 

have identified one neoprene rubber production facility 

currently subject to the Polymers and Resins I MACT standards. 

For the Neoprene Rubber Production source category, we have 

proposed and finalized a decision not to revise the standards 

for those source categories based on our RTR. As noted above, 

this decision was proposed on December 12, 2007 and finalized on 

December 16, 2008. Since the Neoprene Production source 

category was determined to be “low risk” (maximum lifetime 
Page 190 of 387 

cancer risk less than 1-in-1 million), we did not believe it was 

necessary to conduct a facility-wide or demographic risk 

analysis. Therefore, we are not addressing the RTR in today’s 

notice for this source category. 

b. What other actions are we proposing? 

SSM Provisions. The proposed changes to the Group I 

Polymers and Resins MACT, which apply to the Neoprene Rubber 

Production source category, are discussed above in section 

V.B.1.f. 

 Significant Emission Points Not Previously Regulated. We 

identified in the provisions of the Group I Polymers and Resins 

MACT standard that apply to the Neoprene Rubber Production 

source category the absence of a standard for a significant 

emissions source in the category. Specifically, there are no 

back-end process operation emission limits for this source 

category. As these processes are major sources of emissions for 

the one facility in the source category, we are proposing to set 

standards for back-end process operations under CAA sections 

112(d)(2) and (3) in this action. 

 As there is only one facility in the source category, the 

emissions level currently being achieved by this facility 

represents the MACT floor. The annual emissions from the backend process operations at this facility are approximately 

14 TPY. There are 11 separate dryer vents collectively emitting 
Page 191 of 387 

around 14 TPY of toluene. None of the vents are controlled. 

Therefore, we have determined that the MACT floor for the backend process is 14 TPY based on stripping and HAP recovery, given 

current production levels, but which would fluctuate 

proportionally with an increase or decrease in production 

levels. 

 As part of our beyond-the-floor analysis, we considered 

alternatives more stringent than the MACT floor option. We 

identified one option using add-on emission controls that would 

require the ducting of emissions from the back-end process 

operations to a control device, such as an incinerator. This 

option would also require an initial performance test of the 

incinerator and continuous parameter monitoring averaged daily. 

The capital costs of this option are estimated to be 

approximately $1,300,000 and the total annual costs are 

estimated approximately $4,800,000 per year. We estimate that 

an incinerator would achieve an emissions reduction of 

98 percent, resulting in a HAP decrease of approximately 22.6 

TPY, with a cost-effectiveness of approximately $213,000 per 

ton. Table B.5.1 summarizes the impacts of the proposed 

options. 

Table B.5.1. Neoprene Rubber Production Facility Back-End 

Option Impacts

Regulatory Alternatives 

HAP 

emissions 

(TPY) 

Capital 

 Cost 

(million$)

Annual 

 Cost 

(million$/yr)

CostEffectiveness 

as Compared to 

Baseline 
Page 192 of 387 

($/ton HAP 

removed) 

Baseline 23 -- -- -- 

1 (MACT floor) 23 0 0 -- 

2 (Beyond-the-floor) 0.5 1.3 4.8 213,000 

 In addition to the cost and emission reduction impacts 

shown in Table B.5.1, we estimate that the beyond-the-floor 

option will result in increases in criteria pollutant and carbon 

dioxide emissions (PM – 0.8, SO2 – 0.2 TPY, NOx – 55 TPY, CO – 10 

TPY, and CO2 – 33,000 TPY) and an increase in energy use of 

approximately 560,000 million BTU/year at a cost of 

approximately $159,000/year. 

 We believe that the costs and other impacts of this beyondthe-floor option are not reasonable, given the level of emission 

reduction. Therefore, we are proposing Option 1, the MACT floor 

option. We are requesting comment on this analysis and these 

options. 

 As noted above, we have proposed and finalized a decision 

that the MACT standard for neoprene rubber production, prior to 

the implementation of the proposed emission limitation to the 

back-end process operations discussed in this section, provides 

an ample margin of safety to protect public health. Since this 

source category was “low risk” prior to this proposed emission 

limitation, we maintain that after their implementation, the 

rule will continue to provide an ample margin of safety to 
Page 193 of 387 

protect public health. Consequently, we do not believe it will 

be necessary to conduct another residual risk review under CAA 

section 112(f) for this source category 8 years following 

promulgation of new back-end process limitations, merely due to 

the addition of this new MACT requirement. 

6. Ethylene Propylene Rubber Production. 

 Ethylene Propylene Rubber Production is one of the source 

categories for which we proposed and finalized RTR decisions on 

December 12, 2007 (72 FR 70543) and December 16, 2008 (73 FR 

76220), respectively. 

a. Overview of the source category. 

Ethylene propylene rubber is an elastomer prepared from 

ethylene and propylene monomers. Common uses for these 

elastomers include radiator and heater hoses, weather stripping, 

door and window seals for cars, construction plastics blending, 

wire and cable insulation and jackets, and single-ply roofing 

membranes. 

For the Ethylene Propylene Rubber Production source 

category, we have proposed and finalized a decision not to 

revise the standards for this source category based on our RTR. 

As noted above, this decision was proposed on December 12, 2007 

and finalized on December 16, 2008. Since the Ethylene 

Propylene Rubber Production source category was determined to be 

“low risk” (maximum lifetime cancer risk less than 1-in-1 
Page 194 of 387 

million), we did not believe it was necessary to conduct a 

facility-wide or demographic risk analysis. Therefore, we are 

not addressing the RTR in this notice for this source category. 

b. What other actions are we proposing?

SSM Provisions. The proposed changes to the SSM provisions 

for the Group I Polymers and Resins MACT, which apply to the 

Ethylene Propylene Rubber Production source category, are 

discussed above in section V.B.1.f. 

 Significant Emission Points Not Previously Regulated. We 

identified in the provisions of the Group I Polymers and Resins 

MACT standard that apply to the Ethylene Propylene Rubber 

Production source category the absence of a standard for a 

significant emissions source in the category. Specifically, the 

rule requires that emissions from Group 1 front-end process 

vents be routed to a control device that achieves 98 percent 

reduction in organic HAP emissions but does not require the 

control of hydrogen halides and halogens from the outlet of 

combustion devices. All three currently-operating facilities in 

this source category control the organic HAP emissions in 

accordance with the requirements in the rule (i.e., reduce 

organic HAP emissions by 98 percent). This represents the MACT 

floor for this source category. However, one facility routes a 

chlorinated organic compound to a flare, which results in 

emissions of HCl that are not regulated by the current MACT 
Page 195 of 387 

requirements. When chlorinate organics are burned in a flare, 

there are variations in the combustion which likely results in 

the formation of combustion by-products. These combustion byproducts could include trace chlorinated compounds such as 

dioxins and furans. Due to the level of HCl emissions resulting 

from the combustion of chlorinated organic compounds in Group 1 

streams, we are proposing to require control of these HCl 

emissions for the Ethylene Propylene Rubber Production source 

category. 

 As part of our beyond-the-floor analysis, we considered 

alternatives to reduce these HCl emissions, which are more 

stringent than the MACT floor option. We identified the option 

of eliminating the exemption from the requirement to control 

hydrogen halides and halogens from the outlet of combustion 

devices. The one facility reports around 20 TPY of HCl 

emissions resulting from the combustion of chlorinated organic 

compounds in a flare. The other two facilities indicated that 

they do not emit any HCl emissions resulting from the combustion 

of chlorinated organic compounds. We estimated that the capital 

costs for the facility to replace the flare with an incinerator 

followed by a scrubber to reduce the HCl would be approximately 

$985,000 and the total annual costs are estimated to be 

approximately $446,000 per year. While there would be no 

additional reduction in organic HAP from this requirement, the 
Page 196 of 387 

HCl emissions would be reduced by 99 percent, or 19.6 TPY. The 

cost-effectiveness of this option would be approximately $21,000 

per ton. However, this ethylene propylene rubber process is colocated with the halobutyl rubber process, which also vents a 

vent stream containing chlorinated organic compounds to a flare, 

resulting in HCl emissions. We estimated the costs of a single 

incinerator and scrubber to control the streams containing 

chlorinated organics from both the ethylene propylene rubber and 

halobutyl rubber processes. The estimated capital cost of this 

control scenario is $1,100,000 and the annual cost is $640,000 

per year. This would still achieve the same HCl emission 

reduction from the ethylene propylene rubber process (19.6 TPY), 

and the overall cost-effectiveness considering the reductions 

from the ethylene propylene rubber and halobutyl rubber would be 

around $6,700 per ton. Table B.6.1 summarizes the impacts of 

the proposed options. 

Table B.6.1. Ethylene Propylene Rubber Production Facility 

Front-End Options Impacts

Regulatory 

Alternatives 

HAP 

Emissions 

(TPY HAP) 

Capital 

 Cost 

($million)

Annual 

 Cost 

($million/

yr) 

Cost- Effectiveness as 

Compared to Baseline 

($/ton HAP removed) 

Baseline 20 -- -- -- 

1 (MACT floor) 20 0 0 -- 

2 (Beyond-thefloor) 

0.2 1.1* 0.6* 6,700* 

* Assuming a shared control incinerator/scrubber combination is used for both 

the ethylene propylene rubber and halobutyl rubber processes. 
Page 197 of 387 

 In addition to the cost and emission reduction impacts 

shown in Table B.6.1, we estimate that the beyond-the-floor 

option will result in increases in criteria pollutant and carbon 

dioxide emissions (PM – 0.03 TPY, SO2 – 0.006 TPY, NOx – 2 TPY, 

CO – 0.4 TPY, and CO2 – 1,200 TPY), the generation of 

approximately 29 million gallons/year of wastewater, and an 

increase in energy use of approximately 21,000 million BTU/year 

at a cost of approximately $7,000/year. 

 We believe that the costs and other impacts of this beyondthe-floor option are reasonable, given the level of emission 

reduction. Therefore, we are proposing Option 2, the beyondthe-floor option. We are requesting comment on this analysis 

and these options. 

 As noted above, we have proposed and finalized a decision 

that the MACT standard for ethylene propylene rubber production, 

prior to the implementation of the proposed emission limitation 

discussed in this section, provides an ample margin of safety to 

protect public health. Since this source category was “low 

risk” prior to this proposed emission limitation, we maintain 

that after its implementation, which will only further reduce 

HAP emissions, the rule will continue to provide an ample margin 

of safety to protect public health. Consequently, we do not 

believe it will be necessary to conduct another residual risk 

review under CAA section 112(f) for this source category 8 years 
Page 198 of 387 

following promulgation of new limitations, merely due to the 

addition of this new MACT requirement. 

7. Butyl Rubber Production. 

 Butyl Rubber Production is one of the source categories for 

which we proposed and finalized RTR decisions on December 12, 

2007 (72 FR 70543) and December 16, 2008 (73 FR 76220), 

respectively. 

a. Overview of the source category. 

The Butyl Rubber Production source category includes any 

facility that manufactures copolymers of isobutylene and 

isoprene. A typical composition of butyl rubber is 

approximately 97 percent isobutylene and 3 percent isoprene. 

Modified, derivative, and halogenated copolymers and latexes are 

also included in this source category. Butyl rubber is 

typically made by a precipitation (slurry) polymerization 

process in which isobutylene and isoprene are copolymerized in 

methyl chloride solvent. Butyl rubber is very impermeable to 

common gases and resists oxidation. Uses for butyl rubber 

include tires, tubes, and tire products; automotive mechanical 

goods; adhesives, caulks, and sealants; and pharmaceutical uses. 

A specialty group of butyl rubbers are halogenated butyl 

rubbers, which are produced commercially by dissolving butyl 

rubber in hydrocarbon solvent and contacting the solution with 

gaseous or liquid elemental halogens such as chlorine or 
Page 199 of 387 

bromine. For the purpose of the MACT standards, this source 

category is divided into two subcategories: butyl rubber and 

halobutyl rubber. 

For the Butyl Rubber Production source category, we have 

proposed and finalized a decision not to revise the standards 

for this source category based on our RTR. As noted above, this 

decision was proposed on December 12, 2007 and finalized on 

December 16, 2008. Since the Butyl Rubber Production source 

category was determined to be “low risk” (maximum lifetime 

cancer risk less than 1-in-1 million), we did not believe it was 

necessary to conduct a facility-wide or demographic risk 

analysis. Therefore, we are not addressing the RTR in this 

notice for this source category. 

b. What other actions are we proposing?

SSM Provisions. The proposed SSM changes to the Group I 

Polymers and Resins MACT, which apply to the Butyl Rubber 

Production source category, are discussed above in section 

V.B.1.f. 

 Significant Emission Points Not Previously Regulated. We 

identified in the provisions of the Group I Polymers and Resins 

MACT standard that apply to both Butyl Rubber Production 

subcategories the absence of standards for two significant 

emissions sources in each of the Butyl Rubber Production 

subcategories. Specifically, these situations are HCl emissions 
Page 200 of 387 

from front-end process vents and emissions from back-end process 

operations. 

 The rule requires that emissions from Group 1 front-end 

process vents be routed to a control device that achieves 

98 percent reduction in organic HAP emissions but does not 

require the control of hydrogen halides and halogens from the 

outlet of combustion devices. Both facilities in these 

subcategories control the organic HAP emissions in accordance 

with the requirements in the rule (i.e., reduce organic HAP 

emissions by 98 percent). This represents the MACT floor for 

these subcategories. However, these facilities route a 

chlorinated organic compound to a flare, which results in 

emissions of HCl that are exempted from the current MACT 

requirements. Due to the level of HCl emissions resulting from 

the combustion of chlorinated organic compounds in Group 1 

streams, we are proposing to require control of these HCl 

emissions for both the Butyl Rubber Production and Halobutyl 

Rubber Production subcategories. 

 As there is only one facility in each subcategory, the 

existing level of control for organic HAP emissions represents 

the MACT floor. As part of our beyond-the-floor analysis, we 

considered alternatives to reduce the HCl emissions, which are 

more stringent than the MACT floor option. For front-end 

process vents, we identified the option of eliminating the 
Page 201 of 387 

exemption from the requirement to control hydrogen halides and 

halogens from the outlet of combustion devices. The butyl 

rubber facility reported HCl emissions of 30.1 TPY, while the 

halobutyl rubber facility reported 76.8 TPY. Since scrubbers 

could not be installed on the outlet of these combustion devices 

to reduce the HCl emissions by 99 percent, the butyl rubber 

facility and the halobutyl rubber facility would need to install 

new incinerators followed by scrubbers to comply with this 

beyond-the-floor requirement. We estimate that the capital 

costs for this would be $669,000 for the butyl rubber facility 

and $984,000 for the halobutyl rubber facility. The total 

annual costs would be around $235,000 per year for the butyl 

rubber facility and $424,000 per year for the halobutyl rubber 

facility. Since there would be no additional reduction in 

organic HAP emissions from what is being achieved by the current 

controls, the only emission reduction would a 99 percent 

reduction in HCl emissions, or 29.8 TPY for the butyl rubber 

facility and 76 TPY for the halobutyl rubber facility. Thus, 

the cost-effectiveness of these beyond-the-floor options would 

be approximately $7,900 per ton for butyl rubber and $6,000 per 

ton for halobutyl rubber. However, this halobutyl rubber 

process is co-located with an ethylene propylene rubber process, 

which also vents a vent stream containing chlorinated organic 

compounds to a flare, resulting in HCl emissions. As these 
Page 202 of 387 

streams could be controlled using the same equipment at this 

facility, we estimated the costs of a single incinerator and 

scrubber to control the streams containing chlorinated organics 

from both the ethylene propylene rubber and halobutyl rubber 

processes. The estimated capital cost of this control scenario 

is $1,100,000 and the annual cost is $640,000 per year. This 

would still achieve the same HCl emission reduction from the 

halobutyl rubber process (76 TPY), and the overall costeffectiveness considering the reductions from the ethylene 

propylene rubber and halobutyl rubber would be around $6,700 per 

ton. Tables B.7.1 and B.7.2 summarize the impacts of the 

proposed options. 

Table B.7.1. Butyl Rubber Production Facility Front-End Options 

Impacts

Regulatory 

Alternatives 

HAP 

Emissions 

(TPY HAP) 

Capital 

Cost 

($million) 

Annual 

Cost 

($million/yr)

Cost-effectiveness as 

Compared to Baseline 

($/ton HAP removed) 

Baseline 30.1 -- -- -- 

1 (MACT 

floor) 30.1 0 0 -- 

2 (Beyondthe-floor) 0.3 0.6 0.2 $7,900 

Table B.7.2. Halobutyl Rubber Production Facility Front-End 

Options Impacts 

Regulatory 

Alternatives 

HAP 

Emissions 

(TPY HAP) 

Capital 

Cost 

($million) 

Annual 

Cost 

($million/yr)

Cost-effectiveness as 

Compared to Baseline 

($/ton HAP removed) 

Baseline 76.8 -- -- -- 

1 (MACT 

floor) 76.8 0 0 -- 

2 (Beyondthe-floor) 0.8 1.1* 0.6* $6,700* 
Page 203 of 387 

* Assuming a shared control incinerator/scrubber combination is used for both 

the ethylene propylene rubber and halobutyl rubber processes. 

 In addition to the cost and emission reduction impacts 

shown in Table B.7.1 for butyl rubber production, we estimate 

that the beyond-the-floor option will result in increases in 

criteria pollutant and carbon dioxide emissions (PM – 0.004 TPY, 

SO2 – 0.001 TPY, NOx – 2 TPY, CO – 0.05 TPY, and CO2 – 160 TPY), 

the generation of approximately 31 million gallons/year of 

wastewater, and an increase in energy use of around 3,000 

million BTU/year at a cost of approximately $3,000/year. 

 In addition to the cost and emission reduction impacts 

shown in Table B.6.2 for halobutyl rubber production, we 

estimate that the beyond-the-floor option will result in 

increases in criteria pollutant and carbon dioxide emissions (PM 

– 0.03 TPY, SO2 – 0.006 TPY, NOx – 2 TPY, CO – 0.4 TPY, and CO2 – 

1,200 TPY), the generation of approximately 29 million 

gallons/year of wastewater, and an increase in energy use of 

around 21,000 million BTU/year at a cost of approximately 

$7,000/year. 

 We believe that the costs and other impacts of these 

beyond-the-floor options are reasonable, given the level of 

emission reduction. Therefore, we are proposing Option 2, the 

beyond-the-floor option, for both the Butyl Rubber Production 

and Halobutyl Rubber Production subcategories. We are 

requesting comment on this analysis and these options. 
Page 204 of 387 

 We also noted that there are no back-end process operation 

emission limits for either the Butyl Rubber Production or 

Halobutyl Rubber Production subcategories. As there is only one 

facility in each subcategory, the back-end process operations 

emissions level currently being achieved by these facilities 

represents the MACT floor. The annual emissions from the 

uncontrolled back-end process operations at the butyl rubber 

facility are approximately 26 TPY, and 35 TPY at the halobutyl 

facility. There are two separate dryer vent streams at the 

butyl rubber facility, with one stream controlled. The 

controlled stream emits around 28 TPY of hexane. The 

regenerative thermal oxidizer used to control emissions achieves 

approximately 98-percent control. There are four separate dryer 

vents at the halobutyl facility and one vent is controlled. The 

controlled vent emits around 18 TPY of hexane. The regenerative 

thermal oxidizer used to control emissions achieves 

approximately 97-percent control of the hexane emissions. The 

four uncontrolled vents collectively emit around 35 TPY of 

hexane. Therefore, we have determined that the MACT floors for 

these processes are these emission levels, given current 

production levels, but which would fluctuate proportionally with 

an increase or decrease in production levels. 

 As part of our beyond-the-floor analysis, we considered 

alternatives more stringent than the MACT floor option. We 
Page 205 of 387 

identified one option using add-on emission controls that would 

require the ducting of emissions from the uncontrolled back-end 

process operations to a control device, such as an incinerator. 

This option would also require an initial performance test of 

the incinerator and continuous parameter monitoring averaged 

daily. For the Butyl Rubber Production subcategory, the capital 

costs of this option are estimated to be approximately $235,000 

and the total annual costs are estimated to be approximately 

$181,000. For the Halobutyl Rubber Production subcategory, the 

capital costs of this option are estimated to be approximately 

$950,000 and the total annual costs are estimated to be 

approximately $1,600,000 per year. We estimate that an 

incinerator would achieve an emissions reduction of 98 percent, 

resulting in a HAP decrease of approximately 26 TPY for the 

Butyl Rubber Production subcategory and 34 for Halobutyl Rubber 

Production subcategory. The associated cost-effectiveness 

values would be approximately $7,000 per ton for Butyl Rubber 

Production subcategory and $47,000/ton for Halobutyl Rubber 

Production subcategory. Tables B.7.3 and B.7.4 summarize the 

impacts of the proposed options. 

Table B.7.3. Butyl Rubber Production Subcategory Facility BackEnd Option Impacts

Regulatory 

Alternatives 

HAP 

Emissions 

(TPY HAP) 

Capital 

 Cost 

($million)

Annual 

 Cost 

($million/yr

) 

Cost- Effectiveness 

as Compared to 

Baseline 

($/ton HAP removed) 

Baseline 54 -- -- -- 
Page 206 of 387 

1 (MACT floor) 54 0 0 -- 

2 (Beyond-thefloor) 

28 0.2 0.2 $7,000 

Table B.7.4. Halobutyl Rubber Production Subcategory Facility 

Back-End Option Impacts

Regulatory 

Alternatives 

HAP 

Emissions 

(TPY HAP) 

Capital 

 Cost 

($million)

Annual 

 Cost 

($million/yr)

Cost- Effectiveness 

as Compared to 

Baseline 

($/ton HAP removed) 

Baseline 53 -- -- -- 

1 (MACT floor) 53 0 0 -- 

2 (Beyond-thefloor) 

19 1 1.6 $47,000 

 In addition to the cost and emission reduction impacts 

shown in Table B.7.3 for Butyl Rubber Production subcategory, we 

estimate that the beyond-the-floor option will result in 

increases in criteria pollutant and carbon dioxide emissions (PM 

– 0.01, SO2 – 0.003 TPY, NOx – 8 TPY, CO – 0.2 TPY, and CO2 – 600 

TPY) and an increase in energy use of approximately 10,000 

million BTU/year at a cost of approximately $6,000/year. 

 In addition to the cost and emission reduction impacts 

shown in Table B.7.4 for Halobutyl Rubber Production 

subcategory, we estimate that the beyond-the-floor option will 

result in increases in criteria pollutant and carbon dioxide 

emissions (PM – 0.25, SO2 – 0.05 TPY, NOx – 17 TPY, CO – 3 TPY, 

and CO2 – 10,500 TPY) and an increase in energy use of 

approximately 170,000 million BTU/year at a cost of 

approximately $49,000/year. 
Page 207 of 387 

 We believe that the costs and other impacts of the beyondthe-floor option for back-end process operations for the Butyl 

Rubber Production subcategory are reasonable, given the level of 

emission reduction. Therefore, we are proposing Option 2 for 

the Butyl Rubber Production subcategory, the beyond-the-floor 

option. We are requesting comment on this analysis and these 

options. 

 We believe that the costs and other impacts of the beyondthe-floor option for the Halobutyl Rubber Production subcategory 

back-end process operations are not reasonable, given the level 

of emission reduction. Therefore, we are proposing Option 1, 

the MACT floor option. We are requesting comment on this 

analysis and these options. 

 As noted above, we have proposed and finalized a decision 

that the MACT standard for the Butyl Rubber Production source 

category, prior to the implementation of the proposed emission 

limitations to the front-end process vent and back-end process 

operations discussed in this section, provides an ample margin 

of safety to protect public health. Since both subcategories of 

this source category were “low risk” prior to these proposed 

emission limitations, we maintain that after their 

implementation, which will only further reduce HAP emissions, 

the rule will continue to provide an ample margin of safety to 

protect public health. Consequently, we do not believe it will 
Page 208 of 387 

be necessary to conduct another residual risk review under CAA 

section 112(f) for this source category 8 years following 

promulgation of new front-end process vent and back-end process 

limitations, merely due to the addition of these new MACT 

requirements. 

C. What are the results and proposed decisions for the Marine 

Tank Vessel Loading Operations source category?

1. Overview of the source category and MACT standards. 

The NESHAP for MTVLO were promulgated on September 19, 1995 

(60 FR 48388), and codified at 40 CFR part 63, subpart Y. The 

MTVLO MACT-based standards apply to major sources and regulate 

HAP emissions from: land-based terminals, off-shore terminals, 

and the Alyeska Pipeline Service Company’s Valdez Marine 

Terminal. 

MTVLO are conducted at terminals that load liquid 

commodities in bulk, such as crude oil, gasoline, and other 

fuels, and some chemicals and solvent mixtures. The cargo is 

pumped from the terminal’s large, above-ground storage tanks 

through a network of pipes into a storage compartment (tank) on 

the vessel. Emissions occur as vapors are displaced from the 

tank as it is being filled. Most MTVLO facilities are either 

independent terminals or are associated with petroleum 

refineries or synthetic organic chemical manufacturers. 
Page 209 of 387 

For purposes of the MTVLO analysis, we considered only 

emissions from those sources that are part of the MTVLO source 

category. We recognize that there are additional sources of 

emissions at these facilities that are not part of the MTVLO 

source category. Those emission sources include emissions from 

hatch leaks or J tubes during transit, lightering operations, 

ballasting wastewater from non-segregated ballasting, cleaning 

of the cargo tank (especially when changing products), and 

ventilating the cargo tank prior to loading. We are 

investigating these sources to understand their emissions and 

any controls used to reduce those emissions and request 

information about these sources that are currently not part of 

the MTVLO source category. 

The primary emission sources of displaced vapors associated 

with MTVLO activities include open tank hatches and overhead 

vent systems. Other possible emission points are hatch covers 

or domes, pressure or vacuum relief valves, seals, and vents. 

The MACT standards require control of all displaced vapors that 

result from product loading at affected sources irrespective of 

the point from which those vapors are emitted. Typical control 

devices used to reduce HAP emissions at affected facilities 

include vapor collection systems routed to either combustion or 

recovery devices, such as flares, incinerators, absorbers, 

carbon adsorbers, and condensers. 
Page 210 of 387 

When we developed the MTVLO MACT, we estimated that 

approximately 300 major source facilities with MTVLO would be 

subject to the MACT standards. However, data in the 2005 NEI 

were only available for 152 facilities subject to the MACT 

standards and the analyses discussed in this section are based 

on these 152 facilities. We believe the 152 facilities emit HAP 

that are representative of HAP emissions within the source 

category because, based on available information, we expect that 

the rest of the facilities in the source category generally emit 

the same HAP as do the 152 modeled facilities. In addition, we 

expect that these 152 terminals represent the larger-emitting 

terminals, based on the specific terminals included in the 2005 

NEI and the average reported emissions from these terminals (2.8 

TPY of HAP on average). 

Marine terminals with MTVLO located at petroleum refineries 

are not part of the MTVLO source category, but are subject to 

the MTVLO MACT-based standards because the Refinery NESHAP, 40 

CFR part 63, subpart CC, incorporate those requirements by 

reference. However, marine terminals that are part of the 

Petroleum Refineries source category were not included in this 

risk assessment because they are not in the MTVLO source 

category. For these reasons, we are proposing to exclude 

refineries from the additional control requirements that are 

being proposed in this action. Loading operations at marine 
Page 211 of 387 

terminals that are part of the Petroleum Refineries source 

category will be addressed in a separate RTR rulemaking action. 

2. What data were used in our risk analyses?

We initially created a preliminary data set for the source 

category using data in the 2002 NEI Final Inventory, Version 1 

(made publicly available on February 26, 2006), which we 

reviewed and changed where necessary to ensure that the proper 

facilities were included and that emissions from the proper 

processes were allocated to the MTVLO source category. We also 

reviewed the emissions and other data to identify data anomalies 

that could affect risk estimates. On March 29, 2007, we 

published an ANPRM (72 FR 29287) requesting comments on and 

updates to this data set, as well as the data sets for the other 

source categories included in the notice. Comments received in 

response to the ANPRM were reviewed and considered, and 

adjustments were made to the data set where we concluded the 

comments supported such adjustment. After making appropriate 

changes to the data set based on this public data review 

process, we created the data set on which we based the initial 

proposal. This data set was used to conduct the risk assessment 

and other analyses for the MTVLO source category that formed the 

basis for the actions included in the October 2008, proposal. 

Since the initial October 2008 proposal, we have continued 

to scrutinize the existing data set and have evaluated all 
Page 212 of 387 

additional data that became available subsequent to the 

proposal. Uncertainty about possible changes in the industry 

led us to extract more recent data from the NEI and, ultimately, 

to replace the entire 2002 NEI–based MTVLO data set with a data 

set based on the 2005 NEI. Additionally, we continue to work 

with industry representatives to resolve data issues found with 

facilities modeled with a MIR above 1-in-1 million (discussed in 

the next section) using the 2005 NEI data. The industry’s 

review to date is provided in the docket for public review and 

comment. 

The 2005 NEI-based data set shows 420 TPY of total HAP 

emissions from the 152 modeled facilities in the data set. 

Hexane, methyl tertiary butyl ether, toluene, methanol, benzene, 

and xylenes account for the majority of the HAP emissions from 

loading operations included in the MTVLO source category at the 

152 facilities in the data set (approximately 350 TPY, or 79 

percent of the total HAP emissions by mass). These facilities 

also reported relatively small emissions of 56 other HAP. 

 3. What are the results of the risk assessments and 

analyses?

 We have conducted a revised inhalation risk assessment for 

the MTVLO source category. We have also conducted an assessment 

of facility-wide risks and performed a demographic analysis of 
Page 213 of 387 

population risks. Table C.1 provides an overall summary of the 

results of the revised inhalation risk assessment. 

Table C.1. Marine Tank Vessel Loading Operations Revised 

Inhalation Risk Assessment Results* 

Maximum 

Individual 

Cancer Risk 

(in 1 million)2

Maximum 

Chronic Non-cancer 

TOSHI3

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population 

at Risk ≥

1-in-1 

Million 

Annual 

Cancer 

Incidence 

(cases 

per year) 

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum 

OffSite 

Acute 

Noncancer 

HQ4

152 Modeled 

Facilities 20 60 71,000 0.01 0.3 0.9 HQREL = 1 benzene 

300 Major 

Source 

Facilities 

Subject to 

the MTVLO 

MACT 

Standard 

20 60 140,000 0.02 0.3 0.9 

HQREL = 1 

benzene 

* All results are for impacts out to 50 km from every source in the category. 

1

 There were 152 facilities in the data set that were modeled. We believe 

that these facilities are representative of the entire source category and 

that the maximum risks arising from any individual facility in the source 

category are properly characterized. The population risks were scaled up 

based on a linear relationship. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the MTVLO source 

category is the reproductive system. 

4

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

shown use the lowest available acute threshold value, which, in most cases, 

is the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section IV.A of this preamble for 

explanation of acute threshold values. 

 The inhalation risk modeling was performed using actual 

emissions level data. As shown in Table C.1, the results of the 

revised inhalation risk assessment indicate the maximum lifetime 

individual cancer risk could be as high as 20-in-1 million, the 

maximum chronic non-cancer TOSHI value could be up to 0.3. The 

total estimated national cancer incidence from these facilities 

based on actual emission levels at the 152 modeled facilities is 

0.01 excess cancer cases per year or one case in every 100 

years. The total estimated cancer incidence for the MTVLO 
Page 214 of 387 

source category could, however, be as high as 0.02, or one case 

in every 50 years, considering that there may be 300 facilities 

in the source category. The maximum off-facility-site acute HQ 

value could be as high as 1, based on the actual emissions level 

and the REL value for benzene. 

 In evaluating potential differences between actual emission 

levels and emissions allowable under the MACT-based standards, 

we investigated the specific controls in use at facilities 

associated with cancer risks greater than 1-in-1 million and 

determined that the highest factor for one of these facilities 

was 3.0, based on the ability of these facilities to achieve 98-

percent control of emissions where only 97-percent emissions 

control is required by the MACT standards for another facility, 

they could, under MACT, increase emissions by a factor of 3. 

Therefore, the maximum individual cancer risk based on MACTallowable emissions is estimated to be up to 60-in-1 million, 

and the maximum chronic non-cancer TOSHI value is up to 0.9. 

 Table C.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels for the 152 modeled facilities. 

Table C.2. Marine Tank Vessel Loading Operations Facility-Wide 

Risk Assessment Results

Maximum facility-wide individual cancer risk (in 1 

million) 200 

MTVLO source category contribution to this 

maximum facility-wide individual cancer risk1 10% 
Page 215 of 387 

Maximum facility-wide chronic non-cancer TOSHI 4 

MTVLO source category contribution to this 

maximum facility-wide non-cancer TOSHI1 20% 

1

 Percentage shown reflects MTVLO source category contribution to the maximum 

facility-wide risks at the facility with the maximum risk value shown. 

The maximum individual cancer risk from all HAP emissions at a 

facility that contains sources subject to the MTVLO MACT 

standards is estimated to be 200-in-1 million, and the maximum 

chronic non-cancer TOSHI value is estimated to be 4. The 

highest facility-wide cancer risk for a facility that includes a 

MTVLO source is primarily driven by emissions associated with 

sources subject to the organic liquids distribution (OLD) 

NESHAP, 40 CFR part 63, subpart EEEE, and the highest facilitywide non-cancer risk is primarily driven by chemical 

manufacturing processes. The OLD and chemical manufacturing 

process emissions will be addressed as part of our effort to 

develop integrated requirements for the chemical manufacturing 

sector. We intend to develop integrated rules for the chemical 

manufacturing sector over the next 2 years. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on actual emissions levels for the population living 

within 5 km of the facilities, among various demographic groups 

are provided in a report available in the docket for this action 

and summarized in Table C.3 below. 
Page 216 of 387 

Table C.3. Marine Tank Vessel Loading Operations Demographic 

Risk Analysis Results 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) 

Population With Risk Greater Than 1-in-1 Million 

 

Total 

(million

s) 

Minority 

% 

African 

America

n 

% 

Other 

and 

Multiracial 

% 

Hispa

nic 

or 

Latin

o 

% 

Nativ

e 

Ameri

can 

% 

Below 

the 

Pover

ty 

Level 

% 

Over 

25 

W/O 

a HS 

Diplo

ma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 20 0.06 29 7 21 38 0.6 15 19 

Facilitywide 200 0.8 38 18 39 14 0.5 18 18 

 The results of the demographic analysis show that, for the 

MTVLO source category, of the 60,000 people with cancer risk 

greater than 1-in-1 million, 29 percent could be classified as a 

“Minority,” 38 percent are included in the “Hispanic or Latino” 

demographic group, 21 percent are included in the “Other and 

Multiracial” demographic group, 15 percent are included in the 

“Below Poverty Level” demographic group, and 19 percent are 

included in the “Over 25 Without a High School Diploma” 

demographic group. The percentage of the population within 5 km 

of the terminal and with a cancer risk greater than 1-in-1 

million is higher than the typical distribution of these 

demographic groups across the United States. The facility-wide 

demographic analysis shows that many more people (800,000) are 

at cancer risk greater than 1-in-1 million. As with the MTVLO 

analysis, many of the demographic groups have disparate impacts 

compared to the distribution across the United States. 
Page 217 of 387 

 Details of these assessments and analyses can be found in 

the residual risk documentation referenced in section IV.A of 

this preamble, which is available in the docket for this action. 

4. What are our proposed decisions on risk acceptability and 

ample margin of safety?

a. October 2008 proposed decision. 

 In October 2008, we proposed that the risks were acceptable 

because the risk results indicated that cancer risks to the 

individual most exposed to emissions from the category were 

greater than 1-in-1 million, but less than 100-in-1 million, and 

there were no other significant health impacts. We identified 

one emissions control option that would reduce risks in the 

ample margin of safety determination. We proposed that such 

control was not necessary to protect public health with an ample 

margin of safety in light of the high costs and limited 

additional health protection it would provide. We also proposed 

that emissions from the source category posed no potential for 

adverse environmental effects, did not pose potential for human 

health multipathway risks, and were unlikely to cause acute or 

chronic non-cancer health impacts. Therefore, we proposed that 

the existing standards provided an ample margin of safety and 

proposed to re-adopt the existing MACT standards to satisfy 

section 112(f) of the CAA. 

b. Risk acceptability. 
Page 218 of 387 

 The revised risk analysis we performed for this proposal 

indicates that the cancer risks to the individual most exposed 

is 20-in-1 million based on actual emissions and 30-in-1 million 

based on MACT-allowable emissions. The cancer incidence and the 

number of people exposed to cancer risks of 1-in-1 million or 

greater are relatively low, based on actual emissions. The 

analyses show no potential for adverse environmental effects or 

human health multipathway effects, and that chronic, non-cancer 

health impacts are unlikely. The revised assessment did 

indicate that an acute non-cancer HQ as high as 1 could occur, 

based on the REL value. Our additional analysis of facilitywide risks shows that the maximum facility-wide cancer risk is 

200-in-1 millions and the maximum facility-wide non-cancer TOSHI 

is 4. It also shows that the MTVLO processes located at the 

facilities with these maximum risk values contribute 

approximately 10 and 20 percent to such risks, respectively. 

Our additional analyses of the demographics of the exposed 

population show disparities in risks between demographic groups, 

but MTVLO represent a small portion of the population at risk. 

Based on this low cancer risk level and in consideration of 

other health measures and factors, including the low cancer 

incidence (one case in every 100 years) and the low maximum noncancer risk level (TOSHI of 0.3 based on actual emissions and 
Page 219 of 387 

0.5 based on MACT-allowable emissions), we propose that the 

risks from the MTVLO source category are acceptable. 

c. Ample margin of safety. 

 Because we are proposing that the risks are acceptable, but 

still above 1-in-1 million, we then reconsidered our 2008 ample 

margin of safety decision. 

 We have not identified any additional control options or 

any changes to the previously-analyzed control option that would 

further reduce risks from MTVLO that have cancer risks above 1-

in-1 million. Our analysis does not indicate a change in the 

emissions reductions that could be achieved or in the cost of 

control for the control option considered, but ultimately 

rejected, in the October 2008 proposal. Therefore, we continue 

to propose that the current MACT-based standards provide an 

ample margin of safety to protect public health and the 

environment, and we are proposing to re-adopt the existing MACT 

standards to satisfy section 112(f) of the CAA. 

 5. What are our proposed decisions on the technology 

review?

 In the October 10, 2008 proposal, as part of our technology 

review, we stated that we had not identified any advancements in 

practices, processes, and control technologies applicable to the 

emission sources in the MTVLO source category that would result 

in decreased emissions, and, on that basis, proposed to re-adopt 
Page 220 of 387 

the existing MACT standards to satisfy section 112(d)(6) of the 

CAA. In that review, we examined the regulatory requirements 

and/or technical analyses for subsequently-promulgated air 

toxics regulations applicable to source categories with emission 

sources similar to those in the MTVLO source category, and we 

searched the RBLC for controls applicable to VOC- and HAPemitting processes in the MTVLO source category that might 

further reduce HAP emissions. In addition to reviewing 

subsequent regulatory actions applicable to similar types of 

emissions, such as those from loading racks or transfer 

operations, we also conducted a review for other VOC and organic 

HAP-emitting processes that would have similar, technologytransferable controls. We have not identified any additional 

developments in practices, processes, and control technologies 

since the proposal date. Thus, we are continuing to propose no 

changes as a result of the technology review under section 

112(d)(6) of the CAA. 

6. What other actions are we proposing?

a. SSM provisions. 

We reviewed the SSM provisions of the MTVLO NESHAP. The 

MTVLO NESHAP do contain an SSM exemption because they specify 

that 40 CFR 63.560, Table 1 that 40 CFR 63.6(f)(1) applies. 

Consistent with Sierra Club v. EPA, EPA is proposing that 

standards in this rule would apply at all times. We determined 

Deleted: in 
Page 221 of 387 

that there are currently several cross-references in the MTVLO 

NESHAP that could cause some confusion regarding periods of SSM. 

We also determined that the NESHAP do not specifically address 

recordkeeping and reporting requirements during periods of 

malfunction. We are, therefore, proposing several revisions to 

40 CFR part 63, subpart Y to address these issues. We are also 

proposing to add language to 40 CFR 63.563(b)(1) to clarify the 

conditions during which performance tests shall be conducted. 

We are further proposing to revise 40 CFR 63.560, Table 1 to 

specify that the SSM included provisions in 40 CFR 63.6(f)(1), 

40 CFR 63.7(e)(1), and 40 CFR 63.10(c)(10)-(11) of the General 

Provisions do not apply. Finally, we are proposing to 

promulgate an affirmative defense against civil penalties for 

exceedances of emission standards caused by malfunctions, as 

well as criteria for establishing the affirmative defense. 

EPA has attempted to ensure that we have removed any 

provisions in the regulatory text that are inappropriate, 

unnecessary, or redundant in the absence of the SSM exemption. 

We are specifically seeking comment on whether there are any 

such provisions that we have inadvertently overlooked. 

b. Significant emission points not previously regulated. 

 We also conducted a review of the MTVLO NESHAP to 

determine whether there were significant emissions sources for 

which standards were not previously developed. In this review, 
Page 222 of 387 

we identified two subcategories, those facilities emitting less 

than 10/25 TPY of HAP, and those facilities located more than 

0.5 miles from shore, for which the current NESHAP do not 

include emission standards. As discussed below, we considered 

two levels of control (submerged fill and vapor recovery) for 

these two subcategories 

 Submerged fill reduces the amount of emissions generated 

from the loading of vessels by reducing turbulence and misting. 

Use of this technique results in a 60-percent reduction in 

emissions compared to splash loading. We have determined that 

submerged fill is currently used by most, if not all, of the 

facilities. We reached this conclusion based on information 

obtained through contact with industry representatives and the 

Coast Guard about submerged filling. Existing Coast Guard rules 

(46 CFR 153.282) require that “the discharge point of a cargo 

tank filling line must be not higher above the bottom of the 

cargo tank or sump than 10 centimeters (approximately 4 inches) 

or the radius of the filling line, whichever is greater.” 

According to Coast Guard representatives, the radius of the fill 

lines can be up to 6 inches. Since most, if not all facilities 

currently use the submerged fill technique, we concluded that 

this represented the MACT floor when the original rule was 

promulgated. 
Page 223 of 387 

 We have identified that there are controls beyond submerged 

fill that recover vapors from MTVLO facilities that may be costeffective and, thus, suitable for use by facilities in the two 

subcategories facilities that emit less than 10/25 TPY of HAP 

and all facilities located more than 0.5 miles from shore. We 

considered the use of vapor collection and processors, which 

were the basis for the emissions standards applicable to other 

MTVLO, at existing facilities in two subcategories of the MACT 

standards (60 FR 48388). We concluded that the use of vapor 

collection and processing did not reflect the average 

performance of the best-performing 12 percent of existing 

sources in the two subcategories, and, therefore, did not 

constitute the required “floor” level of control. In the 

beyond-the-floor analysis, as explained in the preamble to the 

final rule, we determined that vapor collection and processors 

were not cost-effective (above $80,000 per ton of HAP) (60 FR 

48395), and we did not establish standards based on the use of 

this technology. In addition, there were concerns about the 

safety of handling potentially-explosive vapors and the 

operational complexity of such systems when compared to vapor 

incineration systems. 

Since that time, the safety issues have been addressed, and 

we are now considering the application of controls for the 

higher VOC-emitting MTVLO using recovery devices, such as 
Page 224 of 387 

refrigerated lean oil absorption and carbon bed adsorption. 

Subsequent analysis has determined that these systems are 

currently in use at some MTVLO facilities and that they appear 

to be no more problematic from a safety standpoint than other 

control systems. We developed the vapor collection and recovery 

option for gasoline because recovery technology is appropriate 

for controlling mixtures of compounds and because gasoline is 

the highest-quantity commodity loaded, based on our review of 

the Waterborne Commerce Statistics Center (WCSC) database for 

the United States. The WCSC database contains detailed 

information on the types and quantities of commodities loaded 

and unloaded at United States ports, harbors, waterways, and 

canals. The existing standards include a control threshold of 

10 million bbl/yr for control. We identified lower thresholds 

ranging from 0.5 to 5 million bbl/yr. For gasoline loading, 

uncontrolled emissions resulting from the loading of 5 million 

bbl/yr correspond to approximately 25 TPY of HAP emissions, 

which is our threshold for control under the existing rules. 

Therefore, loading in excess of 5 million bbl/yr of gasoline is 

already required to be controlled under the current standard. 

We estimated the cost-effectiveness and overall impacts of 

a number of applicability thresholds for controls ranging from 

0.5 to 5 million bbl/yr of gasoline. The vapor collection and 

recovery options are shown in Table C.4. As discussed earlier, 
Page 225 of 387 

the 5 million bbl/yr cutoff would not achieve any HAP or VOC 

reductions beyond those required under the current rule. For 

the 1 million bbl/yr cutoff, we estimate an additional 190 TPY 

of HAP emissions and 2,600 TPY of VOC emission reduction can be 

achieved. The cost-effectiveness of these controls is $74,000 

per ton of HAP emission reduction and $5,500 per ton of VOC 

emission reduction. While the HAP cost-effectiveness is higher 

than our historical values, the VOC cost-effectiveness is within 

the range of acceptability. For the 0.5 million bbl/yr option, 

the additional costs of controls is disproportionate to the 

additional emission reduction, so we selected the 1 million 

bbl/yr threshold option for this proposal. 

Table C.4. Cost-Effectiveness and Nationwide Impacts for Vapor 

Collection and Recovery Controls for Sources with gasoline 

loading 

Gasoline 

Loading 

Threshold 

(million 

bbl/yr) 

Capital 

Cost 

(million 

$) 

Total 

annualized 

cost 

(million 

$) 

Recovery 

Credit 

(million 

$) 

Net 

annualized 

cost 

(million 

$) 

HAP 

emission 

reduction

(TPY) 

HAP costeffectiven

ess 

($/ton) 

VOC 

emission 

reductio

n 

(TPY) 

VOC cost -

effectiven

ess 

($/ton) 

5 0 0 0 0 0 --- 0 --- 

1 22 16 1 14 190 74,000 2,600 5,500 

0.5 36 22 2 20 240 85,000 3,200 6,300 

 We considered formats for the standard that may foster the 

use of vapor recovery rather than combustion of the vapors. 

Based on similar MACT standards for gasoline loading of tank 

trucks and rail cars, we believe that vapor recovery is capable 

of achieving an emission limit of less than or equal to 10 

milligrams of total organic compound emissions per liter of 
Page 226 of 387 

gasoline loaded (mg/l). The 10 mg/l emission limit also 

approximates the 97-percent control that is required for the 

larger-emitting, existing MTVLO subcategories. Thus, we propose 

to provide major source facilities the option of either meeting 

97-percent control or the equivalent emission limit of 10 mg/l. 

 In conclusion, when we promulgated the original MACT 

standard, the “floor” (the average performance of the bestperforming 12 percent of sources) for facilities emitting less 

than 10/25 TPY of HAP and facilities located more than 0.5 miles 

from shore was the existing level of control, i.e., submerged 

fill. At that time we did not set standards for those two 

subcategories even though the facilities were using submerged 

fill to reduce emissions and address safety concerns. To 

correct that omission, we are proposing in this action to set 

submerged fill as the floor level of control for these two MTVLO 

subcategories. Additionally, we are proposing vapor recovery as 

an above-the-floor option for those two MTVLO subcategories if 

they load 1 million bbl/yr or more of gasoline. 

 As noted above, we are proposing that the MACT standards, 

prior to the implementation of the proposed emission limitations 

discussed in this section, provide an ample margin of safety to 

protect public health. Therefore, we maintain that after 

implementation, which will further reduce HAP emissions, the 

rule will continue to provide an ample margin of safety to 
Page 227 of 387 

protect public health. Consequently, we do not believe it will 

be necessary to conduct another residual risk review under CAA 

section 112(f) for this source category 8 years following 

promulgation of these limitations. 

D. What are the results and proposed decisions for the 

Pharmaceuticals Production source category?

1. Overview of the source category and MACT Standard. 

 The National Emission Standards for Pharmaceuticals 

Production were promulgated on September 21, 1998 (63 FR 50280) 

and codified at 40 CFR part 63, subpart GGG. The 

Pharmaceuticals Production MACT standards apply to major sources 

of HAP. We identified 27 facilities currently subject to the 

Pharmaceuticals Production MACT standards. 

 The pharmaceutical manufacturing process consists of 

chemical production operations that produce drugs and 

medication. These operations include chemical synthesis 

(deriving a drug’s active ingredient) and chemical formulation 

(producing a drug in its final form). 

 Emission sources at pharmaceutical production facilities 

include breathing and withdrawal losses from chemical storage 

tanks, venting of process vessels, leaks from piping and 

equipment used to transfer HAP compounds (equipment leaks), and 

volatilization of HAP from wastewater streams. 
Page 228 of 387 

 Typical control devices used to reduce HAP emissions from 

process vents include flares, incinerators, scrubbers, carbon 

adsorbers, and condensers. Emissions from storage vessels are 

controlled by floating roofs or by routing them to a control 

device. Emissions from wastewater are controlled by a variety 

of methods, including equipment modifications (e.g., fixed roofs 

on storage vessels and oil water separators; covers on surface 

impoundments containers, and drain systems), treatment to remove 

the HAP (steam stripping, biological treatment), control 

devices, and work practices. Emissions from equipment leaks 

typically are reduced by leak detection and repair work practice 

programs, and in some cases, by equipment modifications. 

2. What data were used in our risk analyses?

We initially created a preliminary data set for the source 

category using data in the 2002 NEI Final Inventory, Version 1 

(made publicly available on February 26, 2006). We reviewed the 

NEI data set and made changes where necessary to ensure the 

proper facilities were included and to ensure the proper 

processes were allocated to the Pharmaceuticals Production 

source category. We also reviewed the emissions and other data 

to identify data anomalies that could affect risk estimates. On 

March 29, 2007, we published an ANPRM (72 FR 29287) for the 

express purpose of requesting comments and updates to this data 

set, as well as to the data sets for the other source categories 
Page 229 of 387 

addressed in that ANPRM. Comments received in response to the 

ANPRM were reviewed and considered, and we made adjustments to 

the data set where we concluded the comments supported such 

adjustment. After making appropriate changes to the data set 

based on this public data review process, the data set on which 

we based the initial proposal was created. This data set was 

used to conduct the risk assessment and other analyses for the 

Pharmaceuticals Production source category that formed the basis 

for the proposed RTR review actions included in the October 10, 

2008 proposal. 

We have continued to scrutinize the existing data set and 

have evaluated any additional data that has become available 

since the October 10, 2008 proposal. Since the time of the 

proposal, we identified an error in the latitude/longitude 

coordinates of one emission point at one facility. This error 

has been corrected in the data set, and no other changes have 

been made to it since the proposal. 

 Methylene chloride, methanol, acetonitrile, and toluene 

account for the majority of the HAP emissions from these 

facilities (approximately 890 TPY, or 85 percent of the total 

HAP emissions by mass). These facilities also reported 

relatively small emissions of 54 other HAP. For more detail, 

see the memo in the docket for this action describing the risk 
Page 230 of 387 

assessment inputs and models for the Pharmaceuticals Production 

source category. 

 We estimate that MACT-allowable emissions from this source 

category could be up to 25 percent greater than the actual 

emissions, primarily from process vents, as it is possible that 

the control devices used at some facilities achieve greater 

emission reductions from these emission sources than what is 

required by the MACT standard. For more detail about this 

estimate of the ratio of actual to MACT-allowable emissions, see 

the memo in the docket for this action describing the estimation 

of MACT-allowable emission levels and associated risks and 

impacts. 

3. What are the results of the risk assessments and analyses?

 We have conducted a revised inhalation risk assessment for 

the Pharmaceuticals Production source category. We have also 

conducted an assessment of facility-wide risk and performed a 

demographic analysis of population risks. Table D.1 provides an 

overall summary of the results of the revised inhalation risk 

assessment. 

Table D.1. Pharmaceuticals Production Revised Inhalation Risk 

Assessment Results* 

Maximum 

individual 

cancer risk 

(in 1 million)2

Maximum 

chronic non-cancer 

TOSHI3

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population 

at risk ≥ 1-

in-1 million 

Annual 

cancer 

incidence 

(cases 

per year) 

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum offsite acute 

non-cancer 

HQ4

27 3 4 2,000 0.0008 0.2 0.4 

HQREL = 2 

glycol 

ethers, 
Page 231 of 387 

chloroform 

HQAEGL-1 = 

0.001 

chloroform * All results are for impacts out to 50 km from every source in the category. 

1

 Number of facilities evaluated in the risk analysis. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the 

Pharmaceutical Production source category is the nervous system. 

4

 The maximum estimated acute exposure concentration was divided by 

available short-term threshold values to develop an array of HQ 

values. HQ values shown use the lowest available acute threshold 

value, which, in most cases, is the REL. When HQ values exceed 1, we 

also show HQ values using the next lowest available acute threshold. 

See section IV.A of this preamble for explanation of acute threshold 

values. 

 The inhalation risk modeling was performed using actual 

emissions level data. As shown in Table D.1, the results of the 

revised inhalation risk assessment indicate the maximum lifetime 

individual cancer risk could be as high as 3-in-1 million, the 

maximum chronic non-cancer TOSHI value could be up to 0.2. The 

total estimated national cancer incidence from these facilities 

based on actual emission levels is 0.0008 excess cancer cases 

per year, or one case in every 1,250 years. The maximum offfacility-site acute HQ value could be as high as 2, based on the 

actual emissions level and the REL value for chloroform. The HQ 

value at this level occurs at a location adjacent to one 

facility fenceline for only a few (13) hours per year. This 

maximum exceedance of the REL value corresponds to an HQAEGL-2

equal to 0.001. We also note a possible exceedance of the 

short-term REL value for glycol ethers at one other facility 

(HQREL = 2). Since there are no other acute threshold values 
Page 232 of 387 

available for glycol ethers, we cannot determine the 

significance of this potential impact. 

 Our analysis of potential differences between actual 

emission levels and emissions allowable under the MACT standards 

indicated that MACT-allowable emission levels may be up to 25 

percent greater than actual emission levels. Considering this 

difference, the risk results from the revised inhalation risk 

assessment indicate the maximum lifetime individual cancer risk 

could be as high as 4-in-1 million, and the maximum chronic noncancer TOSHI value could be up to 0.4 at the MACT-allowable 

emissions level. 

 Table D.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels. 

Table D.2. Pharmaceuticals Production Facility-Wide Risk 

Assessment Results

Maximum facility-wide individual cancer risk (in 

1 million) 40

Pharmaceuticals Production source category 

contribution to this maximum facility-wide 

individual cancer risk1

<1%

Maximum facility-wide chronic non-cancer TOSHI 0.8

Pharmaceuticals Production source category 

contribution to this maximum facility-wide 

chronic non-cancer TOSHI1

<1%

1

 Percentage shown reflects Pharmaceuticals Production source category 

contribution to the maximum facility-wide risks at the facility with 

the maximum risk value shown. 

 The maximum individual cancer risk from all HAP emissions 

at a facility that contains sources subject to the 
Page 233 of 387 

Pharmaceuticals Production MACT standards is estimated to be 40-

in-1 million, and the maximum chronic non-cancer TOSHI value is 

estimated to be 0.8. At the facility where these maximum risk 

values occur, the estimated proportion of the risk attributable 

to the Pharmaceuticals Production source category processes is 

less than one percent for both cancer and non-cancer risk. The 

highest facility-wide cancer risk for a facility that includes a 

pharmaceuticals production source is primarily driven by 

acrylonitrile-butadiene-styrene (ABS) resin production 

processes, and the highest facility-wide non-cancer risk is 

primarily driven by pesticide manufacturing processes. These 

ABS resin and pesticide manufacturing processes will be 

addressed in future residual risk and technology reviews. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on actual emissions levels for the population living 

within 5 km of the facilities, among various demographic groups 

are provided in a report available in the docket for this action 

and summarized in Table D.3 below. 

Table D.3. Pharmaceuticals Production Demographic Risk Analysis 

Results

Population With Risk Greater Than 1-in-1 million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) 

Total 

(millio

ns) 

 Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 
Page 234 of 387 

Source 

Category 3 0.002 12 4 8 34 0.5 32 25 

Facilitywide 40 0.03 18 14 4 12 0.3 21 15 

 The results of the demographic analysis show that, for the 

Pharmaceuticals Production source category, of the population of 

2,000 people with cancer risk greater than 1-in-1 million, 34 

percent are included in the “Hispanic or Latino” demographic 

group, 32 percent are included in the “Below Poverty Level” 

demographic group, and 25 percent are included in the “Over 25 

Without a High School Diploma” demographic group. The 

percentage of the population within 5 km of a pharmaceuticals 

production facility and with a cancer risk greater than 1-in-1 

million is higher than seen for these demographic categories 

based on the distribution of these demographic groups across the 

United States. The table also shows that the results of the 

facility-wide demographic analysis are higher than seen across 

the U.S, for the those included in the “African American,” 

“Below Poverty Level,” and the “Over 25 Without a High School 

Diploma” demographic groups, but the risks are lower than these 

levels for the other demographic groups. 

 Details of these assessments and analyses can be found in 

the residual risk documentation referenced in section IV.A of 

this preamble, which is available in the docket for this action. 
Page 235 of 387 

4. What are our proposed decisions on risk acceptability and 

ample margin of safety?

a. October 2008 Proposed Decision. 

 In our October 10, 2008 proposal, we stated that the risks 

were acceptable because the risk results indicated that cancer 

risks to the individual most exposed to emissions from the 

category of 10-in-1 million were greater than 1-in-1 million but 

less than 100-in-1 million. We then analyzed other risk factors 

and emissions control options in the ample margin of safety 

determination. In this analysis, we found emissions from the 

source category posed no potential for an adverse environmental 

effect, did not pose potential for human health multi-pathway 

risks, and were unlikely to cause acute or chronic non-cancer 

health impacts. We also identified one emissions control option 

that would reduce risks. We proposed that such control was not 

necessary to protect public health with an ample margin of 

safety in light of the high cost and limited additional health 

protection it would provide. Therefore, we proposed that the 

existing standard provided an ample margin of safety, and we 

proposed to re-adopt the existing MACT standard to satisfy 

section 112(f) of the CAA. 

b. Risk Acceptability. 

 The revised inhalation risk analysis we performed for this 

proposal indicates that the cancer risks to the individual most 
Page 236 of 387 

exposed is 3-in-1 million based on actual emissions and up to 4-

in-1 million based on MACT-allowable emissions. The cancer 

incidence and the number of people exposed to cancer risks of 1-

in-1 million or greater are not significantly changed from the 

risk identified in the October 2008 proposal. Similarly, the 

risk analysis continued to show no potential for an adverse 

environmental effect or human health multi-pathway effects, and 

that chronic non-cancer health impacts are unlikely. The 

revised assessment did indicate that an acute non-cancer HQ as 

high as 2 could occur, based on the REL value at a location 

adjacent to the facility fenceline for only a few (13) hours per 

year. However, we do not believe this situation warrants 

additional control considering the overall health effects. 

While our additional analysis of facility-wide risks showed that 

the maximum facility-wide cancer risk is 40-in-1 million, it 

also showed that pharmaceutical sources located at such 

facilities contributed less than 1 percent to such risk. The 

facility-wide analysis indicates that the maximum chronic noncancer risks are unlikely to cause health impacts. Our 

additional analysis of the demographics of the exposed 

population may show disparities in risks between demographic 

groups. Based on this low cancer risk level and in 

consideration of other health measures and factors, including 

the low cancer incidence (one case in every 1,250 years) and the 
Page 237 of 387 

low maximum non-cancer risk level (TOSHI of 0.2 based on actual 

emissions and 0.4 based on MACT-allowable emissions), we propose 

that the risks from the Pharmaceuticals Production source 

category are acceptable. 

c. Ample Margin of Safety. 

 Because we are proposing that the risks are acceptable, but 

still above 1-in-1 million, we then re-considered our 2008 ample 

margin of safety decision. 

 We have not identified any additional control options or 

any changes to the previously-analyzed control option that would 

affect emissions reductions or the costs of control. Therefore, 

we continue to propose that the current MACT standards provide 

an ample margin of safety to protect public health and the 

environment, and we are proposing to re-adopt the existing MACT 

standards to satisfy section 112(f) of the CAA. 

5. What are our proposed decisions on the technology review?

 In the October 10, 2008 proposal, we identified no 

developments in practices, processes, and control technologies 

applicable to the emission sources and thus we did not propose 

any additional controls as necessary under CAA section 

112(d)(6). In that review, we examined the regulatory 

requirements and/or technical analyses for subsequently 

promulgated air toxics regulations with similar types of 

emissions sources as those in the Pharmaceuticals Production 
Page 238 of 387 

source category, and we conducted a search of the RBLC for 

controls for VOC- and HAP-emitting processes in the 

Pharmaceuticals Production source category. We have not 

identified any additional developments in practices, processes, 

and control technologies since the proposal date. Thus, we are 

again proposing that it is not necessary to revise the existing 

MACT standards pursuant to section 112(d)(6). 

6. What other actions are we proposing?

a. SSM Provisions.

We propose to eliminate the SSM exemption in the 

Pharmaceuticals Production MACT standards. Consistent with 

Sierra Club v. EPA, EPA proposes that standards in this rule 

would apply at all times. We are proposing several revisions to 

40 CFR part 63, subpart GGG. Specifically, we are proposing to 

revise Table 1 to indicate that the requirements in 40 CFR 

63.6(e) of the General Provisions do not apply. The 40 CFR 

63.6(e) requires owner or operators to act according to the 

general duty to “operate and maintain any affected source, 

including associated air pollution control equipment and 

monitoring equipment, in a manner consistent with safety and 

good air pollution control practices for minimizing emissions.” 

We are separately proposing to incorporate this general duty to 

minimize into 40 CFR 63.1250(g)(3). The 40 CFR 63.6(e) also 

requires the owner or operator of an affected source to develop 
Page 239 of 387 

a written SSM plan. We are proposing to remove the SSM plan 

requirement. We are proposing to remove the exemption 

provisions for periods of SSM in 40 CFR 63.1250(g), require that 

delay of equipment leak repair plans be contained in a separate 

document in 40 CFR 63.1255(g)(4), revise 40 CFR 63.1257(a) to 

specify the conditions for performance tests, and revise the SSM 

associated monitoring, recordkeeping, and reporting requirements 

in 40 CFR 63.1258(b)(8), 40 CFR 63.1259(a), and 40 CFR 

63.1260(i) to require reporting and recordkeeping for periods of 

malfunction. We are also proposing to revise Table 1 to specify 

that 40 CFR 63.6(f)(1), 40 CFR 63.7(e)(1), the last sentence of 

40 CFR 63.8(d)(3), 40 CFR 63.10(c)(10), (11), and (15), and 40 

CFR 63.10(d)(5) of the General Provisions do not apply. In 

addition, we are proposing to promulgate an affirmative defense 

against civil penalties for exceedances of emission standards 

caused by malfunctions, as well as criteria for establishing the 

affirmative defense. EPA has attempted to ensure that we have 

not incorporated into proposed regulatory language any 

provisions that are inappropriate, unnecessary, or redundant in 

the absence of the SSM exemption. We are specifically seeking 

comment on whether there are any such provisions that we have 

inadvertently incorporated or overlooked. 

b. Rule Improvements Review.
Page 240 of 387 

 We are proposing to correct an editorial error in 40 CFR 

63.1257(e)(2)(iii)(A)(6)(ii). That section specifies several 

criteria under which the inlet to the equalization tank may be 

considered as the inlet to the biological treatment process for 

the purposes of performance tests to show compliance with the 

standards in 40 CFR 63.1256(a)(2)(i). This section incorrectly 

provides that only one of the listed criteria must be met for 

the inlet to the equalization tank to be considered the inlet to 

the biological treatment process. Instead, it should specify 

that all of the criteria must be met. Thus, we are proposing to 

revise this section by changing the “or” before each clause to 

“and,” to clarify that all the criteria of 40 CFR 

63.1256(e)(2)(iii)(A)(6)(ii) must be met for the inlet to the 

equalization tank to be considered as the inlet to the 

biological treatment process. 

E. What are the results and proposed decisions for the Printing 

and Publishing Industry source category?

1. Overview of the source category and MACT Standard. 

 The National Emission Standards for the Printing and 

Publishing Industry were promulgated on May 30, 1996 (61 FR 

27132) and codified at 40 CFR part 63, subpart KK. The Printing 

and Publishing Industry MACT standards apply to major sources of 

HAP. We identified 172 facilities currently subject to the 

Printing and Publishing Industry MACT standards. 
Page 241 of 387 

Printing and publishing facilities are those facilities 

that use rotogravure, flexography, and other methods, such as 

lithography, letterpress, and screen printing, to print on a 

variety of substrates, including paper, plastic film, metal 

foil, and vinyl. The Printing and Publishing Industry MACT 

standards include two subcategories: (1) publication rotogravure 

printing and (2) product and packaging rotogravure and wide-web 

flexographic printing. Emissions at printing and publishing 

facilities result from the evaporation of solvents in the inks 

and from cleaning solvents. The emission points include 

printing presses and associated dryers and ink and solvent 

storage. Control techniques include recovery devices, 

combustion devices, and the use of non-HAP/low-HAP inks and 

cleaning solvents. 

2. What data were used in our risk analyses?

We initially created a preliminary data set for the source 

category using data in the 2002 NEI Final Inventory, Version 1 

(made publicly available on February 26, 2006). We reviewed the 

NEI data and made changes where necessary to ensure the proper 

facilities were included and to ensure the proper processes were 

allocated to the Printing and Publishing Industry source 

category. We also reviewed the emissions and other data to 

identify data anomalies that could affect risk estimates. On 

March 29, 2007, we published an ANPRM (72 FR 29287) for the 
Page 242 of 387 

express purpose of requesting comments on and updates to this 

data set, as well as to the data sets for the other source 

categories addressed in that ANPRM. Comments received in 

response to the ANPRM were reviewed and considered, and we made 

adjustments to the data set where we concluded the comments 

supported such adjustment. After making appropriate changes to 

the data set based on this public data review process, the data 

set on which we based the initial proposal was created. This 

data set was used to conduct the risk assessment and other 

analyses for the Printing and Publishing Industry source 

category that formed the basis for the proposed RTR actions 

included in the October 2008 proposal. 

We have continued to scrutinize the existing data set and 

have evaluated any additional data that became available since 

the October 2008 proposal. Since the time of the proposal, we 

identified errors in some HAP that were reported to be emitted 

and several facilities that were included have permanently 

closed. The data set was updated to correct the errors and 

remove the facilities that have closed. 

Toluene accounts for the majority of the HAP emissions from 

these facilities (approximately 7,105 TPY, or 83 percent of the 

total HAP emissions by mass). These facilities also reported 

relatively small emissions of 58 other HAP. These emissions are 

primarily from the evaporation of HAP present in the inks and 
Page 243 of 387 

other materials applied with rotogravure and flexographic 

processes. 

 We estimate that MACT-allowable emissions from emission 

points within this source category could be up to five times 

greater than the actual emissions because some capture systems 

and control devices used on printers at some facilities could 

achieve greater emission reductions (in the range of 98 to 

possibly 100 percent) than what is required by the MACT standard 

(92 percent). For more detail about this estimate of the ratio 

of actual to MACT-allowable emissions, see the memo in the 

docket for this action describing the estimation of MACTallowable emission levels and associated risks and impacts. 

3. What are the results of the risk assessments and analyses?

 We have conducted a revised inhalation risk assessment for 

the Printing and Publishing Industry source category. We have 

also conducted an assessment of facility-wide risk, and 

performed a demographic analysis of population risks. Table E.1 

provides an overall summary of the results of the revised 

inhalation risk assessment. 

Table E.1. Printing and Publishing Industry Revised Inhalation 

Risk Assessment Results* 

Maximum 

individual 

cancer risk 

(in 1 million)2

Maximum 

chronic non-cancer 

TOSHI3

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population

at risk ≥

1-in-1 

million 

Annual 

cancer 

incidence

(cases 

per year)

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Maximum 

offsite 

acute 

noncancer 

HQ4

172 4 20 300 0.0006 0.08 0.4 HQREL = 
Page 244 of 387 

10 

toluene 

HQAEGL-1

= 0.6 

toluene * All results are for impacts out to 50 km from every source in the category. 

1

 Number of facilities evaluated in the risk analysis. 

2

 Maximum individual excess lifetime cancer risk. 

3

 Maximum TOSHI. The target organ with the highest TOSHI for the Printing and 

Publishing Industry source category is the reproductive system. 

4

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

shown use the lowest available acute threshold value, which in most cases is 

the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section IV.A. of this preamble for 

explanation of acute threshold values. 

 The inhalation risk modeling was performed using actual 

emissions level data. As shown in Table E.1, the risks based on 

these actual emission levels indicate the maximum lifetime 

individual cancer risk could be as high as 4-in-1 million, the 

maximum chronic non-cancer TOSHI value could be up to 0.08. The 

total estimated national cancer incidence from these facilities 

based on the actual emission levels is 0.0006 excess cancer 

cases per year, or one case in every 1,666 years. The maximum 

off-facility-site acute HQ value could be as high as 10, based 

on the actual emissions level and the REL value for toluene. 

The HQ value at this level occurs at a location adjacent to one 

facility fenceline for only a few (90) hours per year. This 

maximum exceedance of the REL value corresponds to an HQAEGL-1

equal to 0.6. 

 Our analysis of potential differences between actual 

emission levels and emissions allowable under the MACT standard 

indicated that MACT-allowable emission levels may be up to five 
Page 245 of 387 

times greater than actual emission levels. Assuming this worst 

case difference occurred at the highest risk facility, the 

scaled risk results from the revised inhalation risk assessment 

would indicate the maximum lifetime individual cancer risk could 

be as high as 20-in-1 million, and the maximum chronic noncancer TOSHI value could be up to 0.4. 

 Table E.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels. 

Table E.2. Printing and Publishing Industry Facility-Wide Risk 

Assessment Results

Maximum facility-wide individual cancer risk (in 1 

million) 20 

Printing and Publishing Industry source 

category contribution to this maximum 

facility-wide individual cancer risk1

< 1% 

Maximum facility-wide chronic non-cancer TOSHI 201

Printing and Publishing Industry source 

category contribution to this maximum 

facility-wide chronic non-cancer TOSHI2

< 1%3

1 After risk modeling was complete, EPA received data that identified an error 

in emissions that caused this highest TOSHI value. After revising the 

emissions value, the highest facility-wide TOSHI is 2 from a different 

facility. 

2

 Percentage shown reflects Printing and Publishing Industry source category 

contribution to the maximum facility-wide risks at the facility with the 

maximum risk value shown. 

3 This percentage reflects the Printing and Publishing Industry source 

category contribution to the highest facility-wide TOSHI of 2, as noted in 

footnote 1 to this table. 

The maximum individual cancer risk from all HAP emissions at a 

facility that contains sources subject to the Printing and 

Publishing Industry MACT standards is estimated to be 20-in-1 

million, and the maximum chronic non-cancer TOSHI value is 
Page 246 of 387 

estimated to be 20. At the facilities where these maximum risk 

values occur, the estimated proportion of the risk attributable 

to the Printing and Publishing Industry source category 

processes is less than one percent for both cancer and noncancer risk. 

 The results of the demographic analyses performed to 

investigate the distribution of risks above 1-in-1 million, 

based on actual emissions levels for the population living 

within 5 km of the facilities, among various demographic groups 

are provided in a report available in the docket for this action 

and summarized in Table E.3 below. 

Table E.3. Printing and Publishing Industry Demographic Risk 

Analysis Results

Population With Risk Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Risk 

(in 1 

million) 

Total 

(millio

ns) 

Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 285 25 12 12 14 0.9 13 13 

Source 

Category 4 0.00005 0 0 0 0 0 11 5 

Facilitywide 20 0.05 14 8 5 5 0.3 9 11 

 The results of the Printing and Publishing Industry source 

category demographic analysis show that for the 50 people living 

within 5 km of a printing and publishing industry facility and 

with a cancer risk greater than 1-in-1 million is less than the 

national averages for the demographic categories displayed in 
Page 247 of 387 

Table E.3, based on the typical distribution of these 

demographic groups across the United States. The table also 

shows that the results of the demographic analysis for the 

facility-wide emissions are similarly less than the national 

averages for these demographic groups. This means the emissions 

from these sources do not create any significant disparate risk 

impacts. 

 Details of these assessments and analyses can be found in 

the residual risk documentation as referenced in section IV.A of 

this preamble, which is available in the docket for this action. 

4. What are our proposed decisions on risk acceptability and 

ample margin of safety?

a. October 2008 Proposed Decision. 

 In our October 10, 2008 proposal, the risk results 

indicated that cancer risk to the individual most exposed to 

emissions from the category was 0.05-in-1 million, which is less 

than 1-in-1 million (i.e., were “low risk”). Therefore, we did 

not conduct an additional ample margin of safety analysis for 

the proposed rule. 

b. Risk Acceptability. 

 While at the time of the October 10, 2008 proposal this 

source category showed low risks (cancer risks to the individual 

most exposed to emissions from the category were less than 1-in1 million), in our revised analysis we found that cancer risks 
Page 248 of 387 

to the individual most exposed to emissions from the category 

were 4-in-1 million based on actual emissions and as high as 20-

in-1 million based on MACT-allowable emissions. This change in 

risk is primarily the result of a cancer health benchmark value 

becoming available for ethyl benzene. The cancer incidence and 

the number of people exposed to cancer risks of 1-in-1 million 

or greater are relatively low, based on actual emissions. The 

analyses show no potential for an adverse environmental effect 

or human health multi-pathway effects, and that chronic noncancer health impacts are unlikely. The revised assessment did 

indicate that an acute non-cancer HQ as high as 10 could occur, 

based on the REL value for toluene at a location adjacent to the 

facility fenceline for up to 90 hours per year. However, given 

the fact that this potential impact does not exceed the AEGL-1 

value for toluene (HQAEGL-1 = 0.6) we do not believe this situation 

warrants additional control considering the overall health 

effects. Our additional analysis of facility-wide risks showed 

that the maximum facility-wide cancer risk is 20-in-1 million 

and the maximum facility-wide non-cancer TOSHI is 20. It also 

showed that the printing and publishing processes located at the 

facilities with these maximum risk values contribute less than 1 

percent to such risks. As previously mentioned, our additional 

analysis of the demographics of the exposed population suggests 
Page 249 of 387 

there are not large disparities in risks between demographic 

groups. 

 Based on this low cancer risk level and in consideration of 

other health measures and factors, including the low cancer 

incidence (one case in every 1,666 years), the low maximum noncancer risk level (TOSHI of 0.08 based on actual emissions and 

0.4 based on MACT-allowable emissions), relatively low facilitywide risks which are not attributable to the printing and 

publishing category, and the lack of disparate impacts in the 

demographic analysis, we propose that the risks from the 

Printing and Publishing Industry source category are acceptable. 

 c. Ample Margin of Safety. 

 Because we are proposing that the risks are acceptable, but 

still above 1-in-1 million, we then re-considered our 2008 ample 

margin of safety decision. Based on these analyses, we continue 

to propose that the current MACT standards provide an ample 

margin of safety to protect public health and the environment, 

and we are proposing to re-adopt the existing MACT standards to 

satisfy section 112(f) of the CAA. 

5. What are our proposed decisions on the technology review?

 In the October 2008 proposal, we identified no advancements 

in practices, processes, and control technologies applicable to 

the emission sources in the Printing and Publishing Industry 

source category in our technology review, and thus we proposed 
Page 250 of 387 

that it was not necessary to revise the existing MACT standards 

pursuant to section 112(d)(6) of the CAA. In that review we 

examined the regulatory requirements and/or technical analyses 

for subsequently promulgated air toxics regulations with similar 

types of emissions sources as those in the Printing and 

Publishing Industry source category, and we conducted a search 

of the RBLC for controls for VOC- and HAP-emitting processes in 

the Printing and Publishing Industry source category. We reexamined these same sources of information to identify any new 

developments since the time of the October 2008 proposal. For 

the purposes of this proposal, we examined the option of 

retrofitting permanent total enclosures onto those controlled 

presses that do not already have permanent total enclosures. A 

permanent total enclosure improves the capture of solvent HAP 

from inks and delivers the additional captured solvent HAP to a 

control device. We estimate the cost-effectiveness of this 

retrofit to be over $50,000 per additional ton of HAP 

controlled. We find the cost of this retrofit to be 

disproportionate to the emission reduction that would be 

achieved. Thus, we are proposing that it is not necessary to 

revise the existing MACT standards pursuant to section 112(d)(6) 

of the CAA. 

6. What other actions are we proposing?

We propose to eliminate the SSM exemption in the Printing 
Page 251 of 387 

and Publishing Industry MACT standard. Consistent with Sierra 

Club v. EPA, EPA proposes that standards in this rule would 

apply at all times. We are proposing several revisions to 40 

CFR part 63, subpart KK regarding the standards that apply 

during periods of SSM. Specifically, we are proposing to revise 

Table 1 to indicate that the requirements of 40 CFR 63.6(e) of 

the General Provisions do not apply. Section 63.6(e) requires 

owners or operators to act according to the general duty to 

“operate and maintain any affected source, including associated 

air pollution control equipment and monitoring equipment, in a 

manner consistent with safety and good air pollution control 

practices for minimizing emissions.” We are separately 

proposing to incorporate this general duty to minimize emissions 

into 40 CFR 63.823. The 40 CFR 63.6(e) also requires the owner 

or operator of an affected source to develop a written SSM plan. 

We are proposing to remove the SSM plan requirement. We are 

also proposing to revise 40 CFR 63.827 to specify the conditions 

for performance tests and to revise 40 CFR 63.829 and 40 CFR 

63.830 to require reporting and recordkeeping for periods of 

malfunction. We are proposing to revise Table 1 to specify that 

40 CFR 63.6(f)(1), 40 CFR 63.7(e)(1), the last sentence of 40 

CFR 63.8(d)(3), 40 CFR 63.10(b)(2)(i), (ii), (iv), and (v), 40 

CFR 63.10(c)(10), (11), and (15), and 40 CFR 63.10(d)(5) of the 

General Provisions do not apply. In addition, we are proposing 
Page 252 of 387 

to promulgate an affirmative defense against civil penalties for 

exceedances of emission standards caused by malfunctions, as 

well as criteria for establishing the affirmative defense. EPA 

has attempted to ensure that we have not incorporated into 

proposed regulatory language any provisions that are 

inappropriate, unnecessary, or redundant in the absence of the 

SSM exemption. We are specifically seeking comment on whether 

there are any such provisions that we have inadvertently 

incorporated or overlooked. 

F. What are the results and proposed decisions for Steel 

Pickling – HCl Process Facilities and Hydrochloric Acid 

Regeneration Plants source category?

1. Overview of the source category and MACT Standard. 

 The National Emission Standards for Steel Pickling – HCl 

Process Facilities and Hydrochloric Acid Regeneration Plants 

were promulgated on June 22, 1999 (64 FR 33202) and codified at 

40 CFR part 63, subpart CCC. The Steel Pickling – HCl Process 

Facilities and Hydrochloric Acid Regeneration Plants MACT 

standards (i.e., Steel Pickling MACT standard) apply to major 

sources of HAP. We estimate that there are approximately 80 

facilities subject to the MACT standards that are currently 

performing steel pickling and/or acid regeneration. Many of 

these facilities are located adjacent to integrated iron and 

steel manufacturing plants or electric arc furnace steelmaking 
Page 253 of 387 

facilities (mini-mills) that produce steel from scrap. 

Facilities that regenerate HCl may or may not be located at 

steel pickling operations. 

The Steel Pickling source category consists of facilities 

that pickle steel, using HCl as the pickling acid, and 

facilities that regenerate the HCl after use, but does not 

include facilities which pickle steel using acids other than 

HCl. 

 Steel pickling is a treatment process in which the heavy 

oxide crust or mill scale that develops on the steel surface 

during hot forming or heat treating is removed chemically in a 

bath of aqueous acid solution. Pickling is a process applied to 

metallic substances that removes surface impurities, stains, or 

crusts to prepare the metal for subsequent plating (e.g., with 

chromium) or other treatment, such as galvanization or painting. 

 The HAP emission points from the steel pickling and acid 

regeneration processes include spray roasters, steel pickling 

baths, steel pickling sprays, and tank vents. 

 Typical control devices used to reduce HAP emissions from 

steel pickling facilities include a packed tower scrubber, sieve 

tray scrubber, or horizontal packed bed scrubber. Each type of 

scrubber is coupled with a demister. The general trend in 

scrubber installations at steel pickling facilities is to 

replace older scrubbers with sieve tray scrubbers, which 
Page 254 of 387 

generate less scrubber effluent (blowdown). For acid 

regeneration roasters, a cyclone or a Venturi pre-concentrator 

is generally used before the emissions are scrubbed in one or 

two counter-current packed tower absorbers. 

2. What data were used in our risk analyses? 

For the Steel Pickling source category, we compiled 

preliminary data sets using data in the 2005 NEI. We reviewed 

these data and made changes where necessary. We also contacted 

several facilities to verify the emissions and emissions release 

characteristic data, and we made updates to the data set based 

on the information received from these communications. This 

updated data set comprises the data set that was used to conduct 

the risk assessments and other analyses that form the basis for 

this proposed action. Hydrochloric acid and chlorine account for 

all of the HAP emissions from the Steel Pickling source category 

(approximately 248 and 164 TPY, respectively). 

 Our analysis of potential differences between actual 

emission levels and emissions allowable under the MACT standards 

indicate that actual emissions and allowable emissions are 

approximately the same as allowable emissions. The available 

data indicate that pickling processes throughout the industry 

are equipped with controls that achieve the HCl and chlorine 

emission limits required by the MACT standards. For more detail 

about this estimate of the ratio of actual to MACT-allowable 
Page 255 of 387 

emissions, see the memo in the docket for this action describing 

the estimation of MACT-allowable emission levels and associated 

risks and impacts. 

3. What are the results of the risk assessments and analyses?

 We have conducted an inhalation risk assessment for the 

Steel Pickling source category. We have also conducted an 

assessment of facility-wide risk and performed a demographic 

analysis of population risks. Table F.1 provides an overall 

summary of the inhalation risk assessment results. 

Table F.1. Steel Pickling Inhalation Risk Assessment Results* 

Maximum 

chronic non-cancer 

TOSHI2

Number of 

Facilities1

Actual 

Emissions 

Level 

Allowable 

Emissions 

Level 

Population 

at risk from 

HI > 1 

Maximum offsite acute 

non-cancer HQ3

51 Modeled 

Facilities 2 2 30 HQREL = 0.4 chlorine 

80 Major Source 

Facilities Subject 

to the MACT 

standard 

2 2 50 HQREL = 0.4 

chlorine 

* All results are for impacts out to 50 km from every source in the category. 

1

 There are 51 facilities in the data set that were modeled. It is believed 

that these facilities are representative of the entire source category and 

that the maximum risks are characterized. The population risks were scaled 

up based on a linear relationship. 

2 Maximum TOSHI. The target organ with the highest TOSHI for the Steel 

Pickling source category is the neurological system. 

3

 The maximum estimated acute exposure concentration was divided by available 

short-term threshold values to develop an array of HQ values. HQ values 

shown use the lowest available acute threshold value, which, in most cases, 

is the REL. When HQ values exceed 1, we also show HQ values using the next 

lowest available acute threshold. See section IV.A of this preamble for 

explanation of acute threshold values. 

 The results of the inhalation risk assessment indicated 

there are no cancer risks or incidences attributable to 
Page 256 of 387 

emissions from the Steel Pickling source category because there 

were no emissions of any HAP with cancer dose-response values 

(i.e., no known carcinogens are emitted from these sources). As 

shown in Table F.1, the maximum chronic non-cancer TOSHI value 

could be as high as 2. The maximum off-facility-site acute HQ 

value could be as high as 0.4, based on the actual emissions 

level and the REL value for chlorine. As our analysis of 

potential differences between actual emission levels and 

emissions allowable under the MACT standards indicate, actual 

emissions are approximately the same as MACT-allowable 

emissions, and the risk results for actual emissions are 

approximately the same as those for MACT-allowable emissions. 

 Table F.2 displays the results of the facility-wide risk 

assessment. This assessment was conducted based on actual 

emission levels for the 51 modeled facilities. 

Table F.2. Steel Pickling Facility-Wide Risk Assessment Results

Maximum Facility-Wide Individual Cancer Risk (in 1 

million) 100 

Steel Pickling source category contribution to this 

maximum facility-wide individual cancer risk NA1

Maximum Facility-Wide Chronic Non-cancer TOSHI 10 

Steel Pickling source category contribution to this 

maximum facility-wide chronic non-cancer TOSHI2 < 1% 

1 The Steel Pickling source category does not contribute to the facility-wide 

cancer risks, as the facilities in this source category do not report 

emissions of any HAP with cancer dose-response values. 

2

 Percentage shown reflects Steel Pickling source category contribution to the 

maximum facility-wide risks at the facility with the maximum risk value 

shown. 
Page 257 of 387 

 The maximum individual cancer risk from all HAP emissions 

at a facility that contains sources subject to the Steel 

Pickling – HCl Process Facilities and Hydrochloric Acid 

Regeneration Plants MACT standards is estimated to be 100-in-1 

million, and the maximum chronic non-cancer TOSHI value is 

estimated to be 10. As noted previously, there were no 

emissions of any HAP with cancer dose-response values from the 

Steel Pickling source category; therefore, this source category 

does not contribute to the maximum facility-wide cancer risk of 

100-in-1 million. At the facility where the maximum TOSHI risk 

value occurs, the estimated proportion of the risk attributable 

to the Steel Pickling source category processes is less than one 

percent. The highest facility-wide cancer risk for a facility 

that includes a steel pickling or HCL regeneration source is 

primarily driven by iron and steel processes and coke oven 

emissions. The iron and steel processes will be addressed in a 

future residual risk review, some coke oven processes (charging, 

top side, and door leaks) have been addressed in a previous 

rulemaking action (70 FR 19992), and other coke oven processes 

(pushing, quenching, and battery stacks) will be addressed in a 

future residual risk review. 

 The results of the demographic analyses performed to 

investigate the distribution of TOSHI greater than 1, based on 

actual emissions levels for the population living within 5 km of 
Page 258 of 387 

the facilities, among various demographic groups are provided in 

a report available in the docket for this action and summarized 

in Table F.3 below. 

Table F.3. Steel Pickling Demographic Risk Analysis Results 

Population With TOSHI Greater Than 1-in-1 Million 

Emissions 

Basis 

Maximum 

Respiratory 

Hazard 

Index Total 

(millio

ns) 

Minority 

% 

African 

American

% 

Other and

Multiracial

% 

Hispanic

or Latino

% 

Native 

American

% 

Below the

Poverty 

Level 

% 

Over 25 

W/O 

a HS 

Diploma 

% 

Nationwide n/a 175 32 16 15 16 0.6 13 13 

Source 

Category 2 0.000045 0 0 0 9 0 6 9 

Facilitywide 10 0.0017 41 34 6 1 0.2 11 13 

 The results of the Steel Pickling source category 

demographic analysis show that there are 45 people exposed to an 

HI of one or greater from the source category and 1,700 people 

exposed to an HI of one or greater for the facility-wide 

emissions. Of this relatively small number of people for the 

source category, none of the groups shows a disparate impact 

compared to the national distribution of non-cancer risk. The 

facility-wide analysis shows a higher percentage population with 

an HI of one or more only for those that could be classified as 

a “Minority” and for those included in the “African American” 

demographic group. 
Page 259 of 387 

Details of these assessments and analyses can be found in 

the residual risk documentation as referenced in section IV.A of 

this preamble, which is available in the docket for this action. 

4. What are our proposed decisions on risk acceptability and 

ample margin of safety?

a. Risk Acceptability. 

 The Steel Pickling source category does not emit HAP that 

are known, probable, or possible carcinogens; therefore, based 

on actual and MACT-allowable emission levels, cancer risks are 

less than 1-in-1 million to the individual most exposed. The 

analyses we performed for this proposal show no potential for an 

adverse environmental effect or human health multi-pathway 

effects, and that acute non-cancer health impacts are unlikely. 

We determined that emissions from the Steel Pickling source 

category would result in chronic non-cancer TOSHI approximately 

equal to 2 for the individual most exposed based on either 

actual emissions or MACT-allowable emissions. This HI value is 

for one facility, which has had compliance issues with the MACT 

standards. The emissions data used in our analysis include 

emissions that are in excess of what is allowed by the MACT 

standards. Work is underway between this facility, OECA at EPA, 

and the State to improve compliance. The next highest HI from 

any facility in the source category is 0.1. Based on this, we 

do not anticipate that MACT-allowable emissions for the sources 
Page 260 of 387 

in this category, or actual emissions when a source is in 

compliance with the MACT standards, would result in adverse 

chronic non-cancer health effects. Our additional analysis of 

facility-wide risks showed that the maximum facility-wide cancer 

risk is 100-in-1 million and the maximum facility-wide noncancer TOSHI is 10. It also showed that the steel pickling 

processes located at the facilities with these maximum risk 

values did not contribute to the cancer risk and contributed 

less than 1 percent to these non-cancer risks. Our additional 

analysis of the demographics of the exposed population may show 

disparities in risks between demographic groups. Based on this 

cancer risk level and in consideration of other health measures 

and factors, including the cancer incidence (no cases) and the 

low maximum non-cancer risk level (TOSHI of 0.2), the lack of 

disparate impacts in the demographic analysis, and the small 

contribution to the facility-wide risks, we propose that the 

risks from the Steel Pickling source category are acceptable. 

b. Ample Margin of Safety.

 We are proposing that the risks are acceptable, and while 

cancer risks were not above 1-in-1 million (the level at which 

we generally perform an ample margin of safety analysis), we 

decided to consider other factors before making a decision 

regarding the need for standards to reduce risks. 
Page 261 of 387 

Based on these analyses, we continue to propose that the 

current MACT standards provide an ample margin of safety to 

protect public health and the environment, and we are proposing 

to re-adopt the existing MACT standards to satisfy section 

112(f) of the CAA. 

5. What are our proposed decisions on the technology review?

We evaluated developments in practices, processes, and 

control technologies applicable to the Steel Pickling source 

category. This included a search of the RBLC and the internet. 

The only advancement that we identified was one technology that 

is being used instead of steel pickling for some applications 

which is called the smooth clean surface (SCS) process. The SCS 

process uses patented roller brushes to remove scale from steel 

sheets and coils. However, this technology leaves the last 

layer of scale, resulting in a product that is rust-resistant, 

but is not conducive to in-line galvanizing, painting, enameling 

or electrolytic plating. Additionally, some types of forming, 

including hydroforming, cold reduction and deep draw cannot be 

used with SCS treated steel. It is therefore not a viable 

replacement for steel pickling operations. Another technology, 

eco pickled surface (EPS), could potentially become a lowemission alternative for steel pickling. EPS blasts steel with 

an acid-free slurry which, like steel pickling, removes all 

layers of scale. However, EPS only became commercially 
Page 262 of 387 

available in 2009 and it is not yet a proven technology. Thus, 

it is premature to consider it as a replacement for steel 

pickling operations. 

Because we determined that the only identified development 

is not technologically feasible at this time, we are proposing 

that it is not necessary to revise the MACT standards pursuant 

to section 112(d)(6). 

6. What other actions are we proposing?

We propose to eliminate the SSM exemption in the Steel 

Pickling MACT standards. Consistent with Sierra Club v. EPA, 

EPA proposes that standards in this rule would apply at all 

times. We are proposing several revisions to 40 CFR part 63, 

subpart CCC regarding the standards that apply during periods of 

SSM. Specifically, we are proposing to revise Table 1 to 

indicate that the requirements in 40 CFR 63.6(e) of the General 

Provisions do not apply. The 40 CFR 63.6(e) requires owner or 

operators to act according to the general duty to “operate and 

maintain any affected source, including associated air pollution 

control equipment and monitoring equipment, in a manner 

consistent with safety and good air pollution control practices 

for minimizing emissions.” We are separately proposing to 

incorporate this general duty to minimize emissions into 40 CFR 

63.1159(c). The 40 CFR 63.6(e) also requires the owner or 

operator of an affected source to develop a written SSM plan. 
Page 263 of 387 

We are proposing to remove the SSM plan requirement. We are 

also proposing to revise 40 CFR 63.1161 to specify the 

conditions for performance tests, to revise the SSM-associated 

reporting and recordkeeping requirements in 40 CFR 63.1164 and 

40 CFR 63.1165 to require reporting and recordkeeping for 

periods of malfunction, and to revise Table 1 to specify that 40 

CFR 63.6(f)(1), 40 CFR 63.7(e)(1), the last sentence of 40 CFR 

63.8(d)(3), 40 CFR 63.10(b)(2)(i),(ii), (vi), and (v), 40 CFR 

63.10(c)(10), (11), and (15), and 40 CFR 63.10(d)(5) of the 

General Provisions do not apply. In addition, we are proposing 

to promulgate an affirmative defense against civil penalties for 

exceedances of emission standards caused by malfunctions, as 

well as criteria for establishing the affirmative defense. EPA 

has attempted to ensure that we have not incorporated into 

proposed regulatory language any provisions that are 

inappropriate, unnecessary, or redundant in the absence of the 

SSM exemption. We are specifically seeking comment on whether 

there are any such provisions that we have inadvertently 

incorporated or overlooked. 

VI. Summary of Proposed Actions 

A. What actions are we proposing as a result of the technology 

reviews?

For the technology review for the chromium electroplating 

and anodizing source categories, we are proposing to amend the 
Page 264 of 387 

rules to prohibit the addition of PFOS-based WAFS to the 

electroplating or anodizing tanks. For these source categories, 

we are also proposing to require several housekeeping 

requirements to minimize emissions of chromium-laden fugitive 

dust from chromium electroplating operations and for owners and 

operators to incorporate these housekeeping procedures in the 

facility operation and maintenance plan. 

 For the Group I Polymers and Resins, MTVLO, Pharmaceuticals 

Production, and Printing and Publishing Industry MACT standards, 

which were addressed in the October 10, 2008 proposal, we have 

reaffirmed our previous determinations that there have been no 

developments in practices, processes, or control technologies. 

Thus, we are continuing to propose that it is not necessary to 

revise the existing MACT requirements based on our CAA section 

112(d)(6) review. 

 For the Steel Pickling--HCl Process Facilities and 

Hydrochloric Acid Regeneration Plants source category, we have 

determined that there have been no developments in practices, 

processes, or control technologies since the promulgation of the 

MACT standards, and we are proposing that it is not necessary to 

revise the existing MACT requirements based on our CAA section 

112(d)(6) review. 

B. What actions are we proposing as a result of the residual 

risk reviews?
Page 265 of 387 

 For the Epichlorohydrin Elastomers Production, HypalonTM

Production, Nitrile Butadiene Rubber Production, Polybutadiene 

Rubber Production, Styrene-Butadiene Rubber and Latex 

Production, MTVLO, Pharmaceuticals Production, and Printing and 

Publishing Industry MACT standards source categories, which were 

addressed in the October 10, 2008 proposal, we have reaffirmed 

our proposed determinations that the MACT standards for these 

source categories provide an ample margin of safety to protect 

public health and prevent adverse environmental effects. Thus, 

we are continuing to propose to re-adopt each of these standards 

for purposes of meeting the requirements of CAA sections 

112(f)(2). 

 For the Hard Chromium Electroplating, Decorative Chromium 

Electroplating, Chromium Anodizing, and Steel Pickling--HCl 

Process Facilities and Hydrochloric Acid Regeneration Plants 

MACT standards source categories, we propose that the MACT 

standards provide an ample margin of safety to protect public 

health and prevent adverse environmental effects. Thus, we are 

proposing to re-adopt these standards for the purpose of meeting 

the requirements of CAA section 112(f)(2). 

C. What other actions are we proposing?

We propose to amend the Hard and Decorative Chromium 

Electroplating and Chromium Anodizing Tanks, Group I Polymers 

and Resins, MTVLO, Pharmaceuticals Production, Printing and 
Page 266 of 387 

Publishing Industry, and Steel Pickling--HCl Process Facilities 

and Hydrochloric Acid Regeneration Plants MACT standards to 

remove the language that exempts facilities from the emissions 

standards that would otherwise be applicable during periods of 

SSM, and to add an affirmative defense against civil penalties 

for exceedances of emission standards caused by malfunctions. 

These changes are being made to ensure these rules are 

consistent with the court’s ruling in Sierra Club v. EPA, 551 

F.3d 1019, which addressed similar provisions in the General 

Provisions that apply to many MACT standards. 

We are also proposing requirements for two MACT standards 

under the authority of section 112(d)(2) and (3) of the CAA to 

address emission points for which emission standards were 

previously not developed. For the MTVLO MACT standard, we are 

proposing to add the requirement to perform submerged fill for 

existing facilities for two subcategories, those emitting less 

than 10/25 tons of HAP, and those located more than 0.5 miles 

from shore. We are also proposing to lower the threshold for 

collecting and controlling the gasoline loading vapors from 10 

million bbl/yr to 1.0 million bbl/yr and are adding an 

alternative standard of 10 mg/l of gasoline loaded. For the 

Group I Polymers and Resins MACT standard source categories, we 

propose to add MACT standards limiting emissions from the backend process operations from the Butyl Rubber Production 
Page 267 of 387 

subcategory, the Halobutyl Rubber Production subcategory, the 

Epichlorohydrin Rubber Production source category, the Nitrile 

Butadiene Rubber Production source category, and the Neoprene 

Rubber Production source category. We also propose to revise 

the MACT standards for front-end process vents from the Butyl 

Rubber Production subcategory, the Halobutyl Rubber Production 

subcategory, and the Ethylene Propylene Rubber Production source 

category by requiring control of HCl emissions resulting from 

the combustion of chlorinated organic compounds. 

In addition, we are proposing minor changes to two MACT 

standards to improve compliance and correct errors. For the 

Chromium Electroplating MACT standard source categories, we are 

proposing to clarify that testing can be performed by either 

Method 306 or Method 306A, and we are proposing to revise Method 

306B to correct inconsistencies between the amendments made to 

subpart N in 2004 (69 FR 42885) and Method 306B. In addition, 

to eliminate a discrepancy between the Chromium Electroplating 

MACT standard and the General Provisions to part 63, we are also 

proposing to revise the trigger for semiannual compliance 

reports to be consistent with General Provisions to part 63. 

For the Pharmaceuticals Production MACT standards, we are 

proposing to correct one typographical error. 

VII. Request for Comments 
Page 268 of 387 

We are soliciting comments on all aspects of this proposed 

action. All comments received during the comment period will be 

considered. In addition to general comments on the proposed 

actions, we are also interested in any additional data that may 

help to reduce the uncertainties inherent in the risk 

assessments. Such data should include supporting documentation 

in sufficient detail to allow characterization of the quality 

and representativeness of the data or information. Please see 

the following section for more information on submitting data. 

VIII. Submitting Data Corrections 

The facility-specific data used in the source category risk 

analyses, facility-wide analyses, and demographic analyses for 

each source category subject to this action are available for 

download on the RTR Web Page at 

http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. These data files 

include detailed information for each HAP emissions release 

point at each facility included in the source category and all 

other HAP emissions sources at these facilities (facility-wide 

emissions sources). However, it is important to note that the 

source category risk analysis included only those emissions 

tagged with the MACT code associated with the source category 

subject to the risk analysis. 

If you believe the data are not representative or are 

inaccurate, please identify the data in question, provide your 
Page 269 of 387 

reason for concern, and provide any “improved” data that you 

have, if available. When you submit data, we request that you 

provide documentation of the basis for the revised values to 

support your suggested changes. To submit comments on the data 

downloaded from the RTR Web page, complete the following steps: 

1) Within this downloaded file, enter suggested revisions 

to the data fields appropriate for that information. The data 

fields that may be revised include the following: 

Data Element Definition 

Control Measure Are control measures in place? 

(yes or no) 

Control Measure Comment 

Select control measure from 

list provided, and briefly 

describe the control measure 

Delete Indicate here if the facility 

or record should be deleted 

Delete Comment Describes the reason for 

deletion 

Emission Calculation 

Method Code For Revised 

Emissions 

Code description of the method 

used to derive emissions. For 

example, CEM, material 

balance, stack test, etc. 

Emission Process Group 

Enter the general type of 

emission process associated 

with the specified emission 

point 

Fugitive Angle 

Enter release angle (clockwise 

from true North); orientation 

of the y-dimension relative to 

true North, measured positive 

for clockwise starting at 0 

degrees (maximum 89 degrees) 

Fugitive Length 

Enter dimension of the source 

in the east-west (x-) 

direction, commonly referred 

to as length (ft) 
Page 270 of 387 

Data Element Definition 

Fugitive Width 

Enter dimension of the source 

in the north-south (y-) 

direction, commonly referred 

to as width (ft) 

Malfunction Emissions Enter total annual emissions 

due to malfunctions (TPY) 

Malfunction Emissions Max 

Hourly 

Enter maximum hourly 

malfunction emissions here 

(lb/hr) 

North American Datum 

Enter datum for 

latitude/longitude coordinates 

(NAD27 or NAD83); if left 

blank, NAD83 is assumed 

Process Comment Enter general comments about 

process sources of emissions 

REVISED Address Enter revised physical street 

address for MACT facility here 

REVISED City Enter revised city name here 

REVISED County Name Enter revised county name here 

REVISED Emission Release 

Point Type 

Enter revised Emission Release 

Point Type here 

REVISED End Date Enter revised End Date here 

REVISED Exit Gas Flow Rate Enter revised Exit Gas 

Flowrate here (ft3

/sec) 

REVISED Exit Gas 

Temperature 

Enter revised Exit Gas 

Temperature here (F) 

REVISED Exit Gas Velocity Enter revised Exit Gas 

Velocity here (ft/sec) 

REVISED Facility Category 

Code 

Enter revised Facility 

Category Code here, which 

indicates whether facility is 

a major or area source 

REVISED Facility Name Enter revised Facility Name 

here 

REVISED Facility Registry 

Identifier 

Enter revised Facility 

Registry Identifier here, 

which is an ID assigned by the 

EPA Facility Registry System 

REVISED HAP Emissions 

Performance Level Code 

Enter revised HAP Emissions 

Performance Level here 

REVISED Latitude Enter revised Latitude here 

(decimal degrees) 

REVISED Longitude Enter revised Longitude here 

(decimal degrees) 

REVISED MACT Code Enter revised MACT Code here 
Page 271 of 387 

Data Element Definition 

REVISED Pollutant Code Enter revised Pollutant Code 

here 

REVISED Routine Emissions Enter revised routine 

emissions value here (TPY) 

REVISED SCC Code Enter revised SCC Code here 

REVISED Stack Diameter Enter revised Stack Diameter 

here (ft) 

REVISED Stack Height Enter revised Stack Height 

here (Ft) 

REVISED Start Date Enter revised Start Date here 

REVISED State Enter revised State here 

REVISED Tribal Code Enter revised Tribal Code here 

REVISED Zip Code Enter revised Zip Code here 

Shutdown Emissions Enter total annual emissions 

due to shutdown events (TPY) 

Shutdown Emissions Max 

Hourly 

Enter maximum hourly shutdown 

emissions here (lb/hr) 

Stack Comment Enter general comments about 

emission release points 

Startup Emissions Enter total annual emissions 

due to startup events (TPY) 

Startup Emissions Max 

Hourly 

Enter maximum hourly startup 

emissions here (lb/hr) 

Year Closed Enter date facility stopped 

operations 

2. Fill in the commenter information fields for each 

suggested revision (i.e., commenter name, commenter 

organization, commenter e-mail address, commenter phone number, 

and revision comments). 

3. Gather documentation for any suggested emissions 

revisions (e.g., performance test reports, material balance 

calculations, etc.). 

4. Send the entire downloaded file with suggested 

revisions in Microsoft® Access format and all accompanying 
Page 272 of 387 

documentation to Docket ID No. EPA-HQ-OAR-2010-0600 (through one 

of the methods described in the ADDRESSES section of this 

preamble). To expedite review of the revisions, it would also 

be helpful if you submitted a copy of your revisions to the EPA 

directly at RTR@epa.gov in addition to submitting them to the 

docket. 

5. If you are providing comments on a facility with 

multiple source categories, you need only submit one file for 

that facility, which should contain all suggested changes for 

all source categories at that facility. We request that all 

data revision comments be submitted in the form of updated 

Microsoft® Access files, which are provided on the 

http://www.epa.gov/ttn/atw/rrisk/rtrpg.html Web page. 

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review. 

Under Executive Order 12866 (58 FR 51735, October 4, 1993), 

this action is a significant regulatory action because it raises 

novel legal and policy issues. Accordingly, EPA submitted this 

action to OMB for review under Executive Order 12866 and any 

changes made in response to OMB recommendations have been 

documented in the docket for this action. 

B. Paperwork Reduction Act. 

The information collection requirements in this rule have 

been submitted for approval to OMB under the Paperwork Reduction 
Page 273 of 387 

Act, 44 U.S.C. 3501, et seq.

The proposed revisions to the SSM provisions for all of the 

standards being amended with this proposed rule will reduce the 

reporting burden associated with having to prepare and submit an 

SSM report. We are not proposing any new paperwork requirements 

to the Pharmaceuticals Production, Printing and Publishing 

Industry, and Steel Pickling – HCl Process Facilities and 

Hydrochloric Acid Regeneration Plants MACT standards. Revisions 

and burden associated with amendments to the Hard and Decorative 

Chromium Electroplating and Chromium Anodizing Tanks; Group I 

Polymers and Resins; and MTVLO MACT standards are discussed in 

the following paragraphs. The OMB has previously approved the 

information collection requirements contained in the existing 

regulations being amended with this proposed rule (i.e., 40 CFR 

part 63, subparts N, U, Y, KK, CCC, and GGG) under the 

provisions of the Paperwork Reduction Act, 44 U.S.C. 3501, et

seq. The OMB control numbers for EPA’s regulations in 40 CFR 

are listed in 40 CFR part 9. Burden is defined at 5 CFR 

1320.3(b).

1. Hard and Decorative Chromium Electroplating and Chromium 

Anodizing Tanks MACT Standard. 

The ICR document prepared by EPA for the amendments to the 

Hard and Decorative Chromium Electroplating and Chromium 

Anodizing Tanks MACT standards has been assigned EPA ICR number 
Page 274 of 387 

1611.08. Burden changes associated with these amendments would 

result from new recordkeeping and reporting requirements 

associated with the new housekeeping requirements being proposed 

with today’s action. The estimated average burden per response 

is 11 hours; the frequency of response is annual for all 

respondents that must comply with the rule’s reporting 

requirements and the estimated average number of likely 

respondents per year is 590. The cost burden to respondents 

resulting from the collection of information includes the total 

capital cost annualized over the equipment’s expected useful 

life (about $171,000), a total operation and maintenance 

component (about $534,000 per year), and a labor cost component 

(about $500,000 per year). 

2. Group I Polymers and Resins MACT Standard. 

The ICR document prepared by EPA for the amendments to the 

Group I Polymers and Resins MACT standards has been assigned EPA 

ICR number 2410.01. Burden changes associated with these 

amendments would result from new recordkeeping and reporting 

requirements associated with the new back-end process operation 

emission limits for epichlorohydrin, neoprene, nitrile butadiene 

rubber, and butyl rubber and the HCl emission limits from the 

front-end process vents for ethylene propylene rubber and butyl 

rubber being proposed with this action. The estimated average 

burden per response is 237 hours; the frequency of response is 
Page 275 of 387 

annual for all respondents that must comply with the rule’s 

reporting requirements and the estimated average number of 

likely respondents per year is 19. The cost burden to 

respondents resulting from the collection of information 

includes the total capital cost annualized over the equipment’s 

expected useful life (averaging $2,800), a total operation and 

maintenance component (averaging $1,000 per year), and a labor 

cost component (averaging $1.1 million per year). 

3. Marine Tank Vessel Loading Operations MACT Standard. 

The ICR document prepared by EPA for the amendments to the 

MTVLO MACT standards has been assigned EPA ICR number 1679.08. 

Burden changes associated with these amendments would result 

from new recordkeeping and reporting requirements associated 

with the vapor recovery requirements being proposed with today’s 

action. The estimated average burden per response is 46 hours; 

the frequency of response is annual for all respondents that 

must comply with the rule’s reporting requirements and the 

estimated average number of likely respondents per year is 18. 

The cost burden to respondents resulting from the collection of 

information includes the total capital cost annualized over the 

equipment’s expected useful life (averaging $3,780), a total 

operation and maintenance component (averaging $108 per year), 

and a labor cost component (averaging $165,000 per year). 

An agency may not conduct or sponsor, and a person is not 
Page 276 of 387 

required to respond to a collection of information unless it 

displays a currently valid OMB control number. 

To comment on the Agency's need for this information, the 

accuracy of the provided burden estimates, and any suggested 

methods for minimizing respondent burden, EPA has established a 

public docket for this rule, which includes these ICR, under 

Docket ID number EPA-HQ-OAR-2010-0600. Submit any comments 

related to the ICR to EPA and OMB. See ADDRESSES section at the 

beginning of this notice for where to submit comments to EPA. 

Send comments to OMB at the Office of Information and Regulatory 

Affairs, Office of Management and Budget, 725 17th Street, NW, 

Washington, DC 20503, Attention: Desk Office for EPA. Since 

OMB is required to make a decision concerning the ICR between 30 

and 60 days after [INSERT DATE OF PUBLICATION IN THE FEDERAL 

REGISTER], a comment to OMB is best assured of having its full 

effect if OMB receives it by [INSERT DATE 30 DAYS FROM DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. The final rule will 

respond to any OMB or public comments on the information 

collection requirements contained in this proposal. 

C. Regulatory Flexibility Act. 

The Regulatory Flexibility Act (RFA) generally requires an 

agency to prepare a regulatory flexibility analysis of any rule 

subject to notice and comment rulemaking requirements under the 

Administrative Procedure Act or any other statute unless the 
Page 277 of 387 

agency certifies that the rule will not have a significant 

economic impact on a substantial number of small entities. 

Small entities include small businesses, small organizations, 

and small governmental jurisdictions. For purposes of assessing 

the impacts of today’s proposed rule on small entities, small 

entity is defined as: (1) A small business that is a small 

industrial entity as defined by the Small Business 

Administration’s regulations at 13 CFR 121.201; (2) a small 

governmental jurisdiction that is a government of a city, 

county, town, school district or special district with a 

population of less than 50,000; and (3) a small organization 

that is any not-for-profit enterprise which is independently 

owned and operated and is not dominant in its field. 

This proposed rule will not impose emission measurements or 

reporting requirements on small entities beyond those specified 

in existing regulations, nor does it change the level of any 

emission standard for amendments to all of the MACT standards 

proposed today, with the exception of the proposed amendments to 

the hard and decorative chromium electroplating and chromium 

anodizing tanks MACT standard. The new housekeeping 

requirements and PFOS use restrictions proposed by these 

amendments to the hard and decorative chromium electroplating 

and chromium anodizing tanks MACT standard may impact small 

entities, but those impacts have been estimated to be nominal. 
Page 278 of 387 

After considering the economic impacts of this proposed 

rule on small entities, I certify that this action will not have 

a significant economic impact on a substantial number of small 

entities. 

We continue to be interested in the potential impacts of 

the proposed rule on small entities and welcome comments on 

issues related to such impacts. 

D. Unfunded Mandates Reform Act. 

This proposed rule does not contain a federal mandate under 

the provisions of Title II of the Unfunded Mandates Reform Act 

of 1995 (UMRA), 2 U.S.C. 1531-1538 for State, local, or tribal 

governments or the private sector. The proposed rule would not 

result in expenditures of $100 million or more for State, local, 

and tribal governments, in aggregate, or the private sector in 

any 1 year. The proposed rule imposes no enforceable duties on 

any State, local, or tribal governments or the private sector. 

Thus, this proposed rule is not subject to the requirements of 

sections 202 or 205 of the UMRA. 

This proposed rule is also not subject to the requirements 

of section 203 of UMRA because it contains no regulatory 

requirements that might significantly or uniquely affect small 

governments because it contains no requirements that apply to 

such governments nor does it impose obligations upon them. 
Page 279 of 387 

E. Executive Order 13132: Federalism. 

This proposed rule does not have federalism implications. 

It will not have substantial direct effects on the States, on 

the relationship between the national government and the States, 

or on the distribution of power and responsibilities among the 

various levels of government, as specified in Executive Order 

13132. None of the facilities subject to this action are owned 

or operated by State governments, and, because no new 

requirements are being promulgated, nothing in this proposal 

will supersede State regulations. Thus, Executive Order 13132 

does not apply to this proposed rule. 

In the spirit of Executive Order 13132, and consistent with 

EPA policy to promote communications between EPA and State and 

local governments, EPA specifically solicits comment on this 

proposed rule from State and local officials. 

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments. 

Subject to the Executive Order 13175 (65 FR 67249, November 

9, 2000) EPA may not issue a regulation that has tribal 

implications, that imposes substantial direct compliance costs, 

and that is not required by statute, unless the Federal 

government provides the funds necessary to pay the direct 

compliance costs incurred by tribal governments, or EPA consults 

with tribal officials early in the process of developing the 
Page 280 of 387 

proposed regulation and develops a tribal summary impact 

statement. EPA has concluded that this proposed rule will not 

have tribal implications, as specified in Executive Order 13175. 

It will not have substantial direct effect on tribal 

governments, on the relationship between the Federal government 

and Indian tribes, or on the distribution of power and 

responsibilities between the Federal government and Indian 

tribes, as specified in Executive Order 13175. Thus, Executive 

Order 13175 does not apply to this action. 

EPA specifically solicits additional comment on this 

proposed action from tribal officials. 

G. Executive Order 13045: Protection of Children from 

Environmental Health Risks and Safety Risks. 

This proposed rule is not subject to Executive Order 13045 

(62 FR 19885, April 23, 1997) because it is not economically 

significant as defined in Executive Order 12866, and because the 

Agency does not believe the environmental health or safety risks 

addressed by this action present a disproportionate risk to 

children. This action would not relax the control measures on 

existing regulated sources, and EPA’s risk assessments (included 

in the docket for this proposed rule) demonstrate that the 

existing regulations are health protective. 

H. Executive Order 13211: Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use. 
Page 281 of 387 

 This action is not a “significant energy action” as defined 

under EO 13211, “Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use” (66 FR 

28355, May 22, 2001), because it is not likely to have 

significant adverse effect on the supply, distribution, or use 

of energy. This action will not create any new requirements for 

sources in the energy supply, distribution, or use sectors. 

I. National Technology Transfer and Advancement Act. 

 Section 12(d) of the National Technology Transfer and 

Advancement Act of 1995 (NTTAA), Public Law No. 104-113, 12(d) 

(15 U.S.C. 272 note) directs EPA to use voluntary consensus 

standards (VCS) in its regulatory activities unless to do so 

would be inconsistent with applicable law or otherwise 

impractical. VCS are technical standards (e.g., materials 

specifications, test methods, sampling procedures, and business 

practices) that are developed or adopted by VCS bodies. The 

NTTAA directs EPA to provide Congress, through OMB, explanations 

when the Agency decides not to use available and applicable VCS. 

 This proposed rulemaking does not involve technical 

standards. Therefore, EPA is not considering the use of any 

VCS. 

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations. 
Page 282 of 387 

Executive Order 12898 (59 FR 7629, February 16, 1994) 

establishes Federal executive policy on environmental justice. 

Its main provision directs Federal agencies, to the greatest 

extent practicable and permitted by law, to make environmental 

justice part of their mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or 

environmental effects of their programs, policies, and 

activities on minority populations and low-income populations in 

the United States. 

To examine the potential for any environmental justice 

issues that might be associated with each source category, we 

evaluated the distributions of HAP-related cancer and non-cancer 

risks across different social, demographic, and economic groups 

within the populations living near the facilities where these 

source categories are located. The methods used to conduct 

demographic analyses for this rule are described in section IV.A 

of the preamble for this rule. The development of demographic 

analyses to inform the consideration of environmental justice 

issues in EPA rulemakings is an evolving science. The EPA 

offers the demographic analyses in this rulemaking as examples 

of how such analyses might be developed to inform such 

consideration, and invites public comment on the approaches used 

and the interpretations made from the results, with the hope 
Page 283 of 387 

that this will support the refinement and improve utility of 

such analyses for future rulemakings. 

For this analysis, we analyzed risks due to the inhalation 

of HAP in two separate ways. In the first approach, we focus 

the analysis on the total populations residing within 5 km of 

each facility (source category and facility-wide), regardless of 

their estimated risks, and examine the distributions of 

estimated risk across the various demographic groups within 

those 5 km circles. In the other, we focus the analysis only on 

the populations within 5 km of any facility who are estimated to 

have HAP exposures which result in cancer risks of 1-in-1 

million or greater or non-cancer HI of 1 or greater (based on 

the emissions of the source category or the facility, 

respectively), once again examining the distributions of those 

risks across various demographic groups. In each approach, we 

compare the percentages of particular demographic groups to the 

total number of people in those demographic groups. In this 

preamble, we only present the results of the second approach 

since it focuses on the significant risks from either the source 

category or the facility-wide emissions. The results of both 

approaches are documented in memos to the docket for each of the 

source categories covered in this proposal. 

As described in the preamble, for the Epichlorohydrin 

Elastomers Production, HypalonTM Production, Nitrile Butadiene 
Page 284 of 387 

Rubber Production, Polybutadiene Rubber Production, StyreneButadiene Rubber and Latex Production, MTVLO, Pharmaceuticals 

Production, and Printing and Publishing Industry MACT standard 

source categories, which were addressed in the October 10, 2008, 

proposal, we have reaffirmed our proposed determinations that 

the MACT standards for these source categories provide an ample 

margin of safety to protect public health and prevent adverse 

environmental effects. For the Hard Chromium Electroplating, 

Decorative Chromium Electroplating, Chromium Anodizing, and 

Steel Pickling--HCl Process Facilities and Hydrochloric Acid 

Regeneration Plants MACT standard source categories, we propose 

the MACT standards provide an ample margin of safety to protect 

public health and prevent adverse environmental effects. 

 Our analyses also show that, for all the source categories 

evaluated, there is no potential for an adverse environmental 

effect or human health multipathway effects, and that acute and 

chronic non-cancer health impacts are unlikely. Our additional 

analysis of facility-wide risks showed that the maximum 

facility-wide cancer risks for all source categories are within 

the range of acceptable risks, and that the maximum chronic noncancer risks are unlikely to cause health impacts. Our 

additional analysis of the demographics of the exposed 

population may show disparities in risks between demographic 

groups for all three categories; EPA has determined that, 
Page 285 of 387 

although there may be a disparity in risks between demographic 

groups, no group is exposed to unacceptable level of risk. The 

proposed rule would not relax the control measures on sources 

regulated by the rule, and, therefore, would not increase risks 

to any populations exposed to these sources. 
National Emission Standards for Hazardous Air Pollutant 

Emissions: Hard and Decorative Chromium Electroplating and 

Chromium Anodizing Tanks; Group I Polymers and Resins; Marine 

Tank Vessel Loading Operations; Pharmaceuticals Production; The 

Printing and Publishing Industry; and Steel Pickling--HCl 

Process Facilities and Hydrochloric Acid Regeneration Plants 

--Page 286 of 387 

 Subject to the proposed regulated by the rule and, therefore, 

would not increase risks to any populations exposed to these 

sources. 

List of Subjects in 40 CFR Part 63

 Environmental protection, Air pollution control, Reporting 

and recordkeeping requirements, Volatile organic compounds. 

____________________________ 

Dated: 

____________________________ 

Lisa P. Jackson, 

Administrator. 
Page 287 of 387 

For the reasons stated in the preamble, the Environmental 

Protection Agency proposes to amend title 40, chapter I of the 

Code of Federal Regulations as follows: 

PART 63-–[AMENDED] 

1. The authority citation for part 63 continues to read 

as follows: 

Authority: 42 U.S.C. 7401, et seq. 

Subpart N-–[AMENDED] 

2. Section 63.341 is amended by: 

a. Adding, in alphabetical order in paragraph (a), 

definitions for “affirmative defense,” “contains hexavalent 

chromium,” and “perfluorooctyl sulfonate (PFOS)-based fume 

suppressant”; and 

b. Revising paragraph (b)(10) to read as follows: 

§63.341 Definitions and nomenclature. 

(a) * * * 

Affirmative defense means, in the context of an enforcement 

proceeding, a response or a defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the 

merits of which are independently and objectively evaluated in a 

judicial or administrative proceeding. 

* * * * * 

Contains hexavalent chromium means, the substance consists 

of, or contains 0.1 percent or greater by weight, chromium 
Page 288 of 387 

trioxide, chromium (VI) oxide, chromic acid, or chromic 

anhydride. 

* * * * * 

Perfluorooctyl sulfonate (PFOS)-based fume suppressant 

means a fume suppressant that contains 1 percent or greater PFOS 

by weight. 

* * * * * 

(b) * * * 

(10) VRtot = the average total ventilation rate for the 

three test runs as determined at the outlet by means of the 

Method 306 or 306A testing specified in appendix A of this part 

in dscm/min. 

3. Section 63.342 is amended by: 

a. Revising paragraph (a); 

b. Revising paragraph (b)(1); 

c. Adding paragraph (c)(1)(iv); 

d. Adding paragraph (c)(2)(vi); 

e. Adding paragraph (d)(3); 

f. Redesignating and revising existing paragraphs (e)(2) 

and (e)(3) as paragraphs (e)(3) and (e)(4); 

g. Adding paragraph (e)(2); 

h. Adding paragraph (f)(3)(i)(F); and 

i. Adding Table 2 to read as follows: 
Page 289 of 387 

§63.342 Standards 

 (a)(1) At all times, each owner or operator must operate 

and maintain any affected source subject to the requirements of 

this subpart, including associated air pollution control 

equipment and monitoring equipment, in a manner consistent with 

safety and good air pollution control practices for minimizing 

emissions. The general duty to minimize emissions does not 

require the owner or operator to make any further efforts to 

reduce emissions if levels required by this standard have been 

achieved. Determination of whether such operation and 

maintenance procedures are being used will be based on 

information available to the Administrator which may include, 

but is not limited to, monitoring results, review of operation 

and maintenance procedures, review of operation and maintenance 

records, and inspection of the source. 

(2) Each owner or operator of an affected source subject 

to the provisions of this subpart shall comply with these 

requirements in this section on and after the compliance dates 

specified in §63.343(a). All affected sources are regulated by 

applying maximum achievable control technology. 

* * * * * 

(b) * * * 

(1) The emission limitations in this section apply during 

tank operation as defined in §63.341, and during periods of 
Page 290 of 387 

startup and shutdown as these are routine occurrences for 

affected sources subject to this subpart. In response to an 

action to enforce the standards set forth in this subpart, you 

may assert a civil defense to a claim for civil penalties for 

exceedances of such standards that are caused by a malfunction, 

as defined in 40 CFR 63.2. Appropriate penalties may be 

assessed, however, if the respondent fails to meet it’s burden 

of proving all the requirements in the affirmative defense. The 

affirmative defense shall not be available for claims for 

injunctive relief. 

(i) To establish the affirmative defense in any action to 

enforce such a limit, the owners or operators of facilities must 

timely meet the notification requirements of paragraph (1)(ii) 

of this subsection, and must prove by a preponderance of 

evidence that: 

(A) The excess emissions were caused by a sudden, short, 

infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, or of a process to operate in a normal an 

usual manner; and could not have been prevented through careful 

planning, proper design or better operation and maintenance 

practices; and did not stem from any activity or event that 

could have been foreseen and avoided, or planned for; and were 

not part of a recurring pattern indicative of inadequate design, 

operation, or maintenance; and 
Page 291 of 387 

(B) Repairs were made as expeditiously as possible when 

the applicable emission limitations were being exceeded. Offshift and overtime labor were used, to the extent practicable to 

make these repairs; and 

(C) The frequency, amount and duration of the excess 

emissions (including any bypass) were minimized to the maximum 

extent practicable during periods of such emissions; and 

(D) If the excess emissions resulted from a bypass of 

control equipment or a process, then the bypass was unavoidable 

to prevent loss of life, severe personal injury, or severe 

property damage; and 

(E) All possible steps were taken to minimize the impact 

of the excess emissions on ambient air quality, the environment, 

and human health; and 

(F) All emissions monitoring and control systems were kept 

in operation if at all possible; and 

(G) Your actions in response to the excess emissions were 

documented by properly signed, contemporaneous operating logs; 

and 

(H) At all times, the facility was operated in a manner 

consistent with good practices for minimizing emissions; and 

(I) The owner or operator has prepared a written root 

cause analysis to determine, correct and eliminate the primary 

causes of the malfunction and the excess emissions resulting 
Page 292 of 387 

from the malfunction event at issue. The analysis shall also 

specify, using the best monitoring methods and engineering 

judgment, the amount of excess emissions that were the result of 

the malfunction. 

(ii) Notification. The owner or operator of the facility 

experiencing an exceedance of its emission limit(s) during a 

malfunction shall notify the Administrator by telephone or 

facsimile (FAX) transmission as soon as possible, but no later 

two business days after the initial occurrence of the 

malfunction, if it wishes to avail itself of an affirmative 

defense to civil penalties for that malfunction. The owner or 

operator seeking to assert an affirmative defense shall also 

submit a written report to the Administrator within 30 days of 

the initial occurrence of the exceedance of the standard in this 

subpart to demonstrate, with all necessary supporting 

documentation, that it has met the requirements set forth in 

paragraph (1)(i) of this subsection. 

* * * * * 

(c)(1) * * * 

(iv) After 3 years from date of publication of the final 

rule amendments in the Federal Register, the owner or operator 

of an affected open surface hard chromium electroplating tank 

shall not add PFOS-based fume suppressants to any affected open 

surface hard chromium electroplating tank. 
Page 293 of 387 

* * * * * 

(2) * * * 

(vi) After 3 years from date of publication of the final 

rule amendments in the Federal Register, the owner or operator 

of an affected enclosed hard chromium electroplating tank shall 

not add PFOS-based fume suppressants to any affected enclosed 

hard chromium electroplating tank. 

* * * * * 

 (d) * * * 

(3) After 3 years from date of publication of the final 

rule amendments in the Federal Register, the owner or operator 

of an affected decorative chromium electroplating tank or an 

affected chromium anodizing tank shall not add PFOS-based fume 

suppressants to any affected decorative chromium electroplating 

tank or chromium anodizing tank. 

 (e) * * * 

(2) After 3 years from date of publication of the final 

rule amendments in the Federal Register, the owner or operator 

of an affected decorative chromium electroplating tank using a 

trivalent chromium bath shall not add PFOS-based fume 

suppressants to any affected decorative chromium electroplating 

tank. 

(3) Each owner or operator of an existing, new, or 

reconstructed decorative chromium electroplating tank that uses 
Page 294 of 387 

a trivalent chromium bath that does not incorporate a wetting 

agent as a bath ingredient is subject to the standards of 

paragraph (d) of this section. 

(4) Each owner or operator of an existing, new, or 

reconstructed decorative chromium electroplating tank that had 

been using a trivalent chromium bath that incorporated a wetting 

agent and ceases using this type of bath must fulfill the 

reporting requirements of §63.347(i)(3) and comply with the 

applicable emission limitation within the timeframe specified in 

§63.343(a)(7). 

(f) * * * 

(3) * * * 

(i) * * * 

(F) The plan shall include housekeeping procedures, as 

specified in Table 2 of this section. 

* * * * * 

Table 2 to §63.342—Housekeeping Practices 

For You must: 

At this minimum 

frequency 

(a) Store the substance in 

a closed container in an 

enclosed storage area; AND 

1. Any substance At all times. 

that contains 

hexavalent 

chromium. (b) Use a closed container 

when transporting the 

substance from the 

enclosed storage area. 

Whenever 

transporting 

substance. 
Page 295 of 387 

For You must: 

At this minimum 

frequency 

(a) Install drip trays 

that collect and return to 

the tank any bath solution 

that drips or drains from 

parts as the parts are 

removed from the tank; OR 

Prior to 

operating the 

tank. 

2. Each affected 

tank, to minimize 

spills of bath 

solution that 

result from 

dragout. 

(b) Contain and return to 

the tank all solution that 

drains or drips from parts 

as the parts are removed 

from the tank. 

Whenever 

removing parts 

from an affected 

tank. 

3. Each spraying 

operation for 

removing excess 

chromic acid from 

parts removed from 

an affected tank. 

Install a splash guard to 

minimize overspray and to 

ensure that any hexavalent 

chromium laden liquid is 

returned to the 

electroplating or 

anodizing tank. 

Prior to any 

such spraying 

operation. 

4. Each operation 

that involves the 

handling or use of 

any substance that 

contains hexavalent 

chromium. 

Clean up, or otherwise 

contain, all spills of the 

substance. 

Within 1 hour of 

the spill. 

(a) Clean the surfaces 

using one or more of the 

following methods: 

(i) HEPA vacuuming; 

(ii) Hand-wiping with a 

damp cloth; 

(iii) Wet mopping; 

(iv) Other cleaning method 

approved by the permitting 

agency; OR 

At least once 

every 7 days. 

5. All surfaces 

within the enclosed 

storage area, open 

floor area, 

walkways around 

affected tanks, or 

any surface 

potentially 

contaminated with 

hexavalent chromium 

that accumulates or 

potentially 

accumulates dust. 

(b) Apply a non-toxic 

chemical dust suppressant 

to the surfaces. 

According to 

manufacturer’s 

recommendations. 

6. All buffing, 

grinding, or 

polishing 

operations. 

Separate the operation 

from any affected 

electroplating or 

anodizing operation by 

installing a physical 

barrier; the barrier may 

take the form of plastic 

strip curtains. 

Prior to 

beginning the 

buffing, 

grinding, or 

polishing 

operation. 
Page 296 of 387 

For You must: 

At this minimum 

frequency 

7. All chromium or 

chromium-containing 

wastes generated 

from housekeeping 

activities. 

Store, dispose, recover, 

or recycle the wastes 

using practices that do 

not lead to fugitive dust 

and in accordance with 

hazardous waste 

requirements. 

At all times. 

4. Section 63.343 is amended by revising paragraph (a)(8) 

to read as follows: 

§63.343 Compliance provisions. 

(a) * * * 

 (8) No later than 6 months from date of publication of the 

final amendments in the Federal Register, the owner or operator 

of an affected source that is subject to the standards in 

paragraphs §63.342(c) or (d) shall implement the housekeeping 

procedures specified in Table 2 of §63.342. 

* * * * * 

5. Section 63.344 is amended by: 

a. Revising paragraph (a); 

b. Revising paragraphs (e)(3)(iii), (e)(3)(iv), and 

(e)(3)(v); and 

c. Revising paragraphs (e)(4)(ii) and (e)(4)(iv) to read 

as follows: 

§63.344 Performance test requirements and test methods.
Page 297 of 387 

 (a) Performance test requirements. Performance tests 

shall be conducted using the test methods and procedures in this 

section. Performance tests shall be conducted under such 

conditions as the Administrator specifies to the owner or 

operator based on representative performance of the affected 

source for the period being tested. Upon request, the owner or 

operator shall make available to the Administrator such records 

as may be necessary to determine the conditions of performance 

tests. Performance test results shall be documented in complete 

test reports that contain the information required by paragraphs 

(a)(1) through (9) of this section. The test plan to be 

followed shall be made available to the Administrator prior to 

the testing, if requested. 

* * * * * 

(e) * * * 

(3) * * * 

(iii) Perform Method 306 or 306A testing and calculate an 

outlet mass emission rate. 

(iv) Determine the total ventilation rate from the 

affected sources (VRinlet) by using equation 1: 

 (1) 
Page 298 of 387 

where VRtot is the average total ventilation rate in dscm/min for 

the three test runs as determined at the outlet by means of 

the Method 306 or 306A testing; IDAi is the total inlet area 

for all ducts associated with affected sources; ∑IAtotal is 

the sum of all inlet duct areas from both affected and 

nonaffected sources; and VRinlet is the total ventilation 

rate from all inlet ducts associated with affected sources. 

(v) Establish the allowable mass emission rate of the 

system (AMRsys) in milligrams of total chromium per hour (mg/hr) 

using equation 2: 

∑VRinlet × EL × 60 minutes/hour = AMRsys (2) 

where Σ VRinlet is the total ventilation rate in dscm/min from the 

affected sources, and EL is the applicable emission 

limitation from §63.342 in mg/dscm. The allowable mass 

emission rate (AMRsys) calculated from equation 2 should be 

equal to or more than the outlet three-run average mass 

emission rate determined from Method 306 or 306A testing in 

order for the source to be in compliance with the standard. 

(4) * * * 

(ii) Determine the total ventilation rate for each type of 

affected source (VRinlet,a)using equation 3: 
Page 299 of 387 

 (3) 

where VRtot is the average total ventilation rate in dscm/min for 

the three test runs as determined at the outlet by means of 

the Method 306 or 306A testing; IDAi,a is the total inlet 

duct area for all ducts conveying chromic acid from each 

type of affected source performing the same operation, or 

each type of affected source subject to the same emission 

limitation; ∑IAtotal is the sum of all duct areas from both 

affected and nonaffected sources; and VRinlet,a is the total 

ventilation rate from all inlet ducts conveying chromic 

acid from each type of affected source performing the same 

operation, or each type of affected source subject to the 

same emission limitation. 

* * * * * 

(iv) Establish the allowable mass emission rate of the 

system (AMRsys) in milligrams of total chromium per hour (mg/hr) 

using equation 8, including each type of affected source as 

appropriate: 

AMRhc1+ AMRhc2+ AMRdc+ AMRca= AMRsys (8) 

The allowable mass emission rate calculated from equation 8 

should be equal to or more than the outlet three-run average 
Page 300 of 387 

mass emission rate determined from Method 306 or 306A testing in 

order for the source to be in compliance with the standards. 

* * * * * 

 6. Section 63.346 is amended by revising paragraphs 

(b)(4) and (b)(13) to read as follows: 

§63.346 Recordkeeping requirements.

* * * * * 

(b) * * * 

(4) Records of actions taken during periods of malfunction 

to minimize emissions in accordance with §63.342(a)(1), 

including corrective actions to restore malfunctioning process 

and air pollution control and monitoring equipment to its normal 

or usual manner of operation; 

* * * * * 

(13) For sources using fume suppressants to comply with 

the standards, records of the date and time that fume 

suppressants are added to the electroplating or anodizing bath 

and records of the fume suppressant manufacturer and product 

name; 

* * * * * 

7. Section 63.347 is amended by: 

a. Redesignating paragraphs (g)(3)(xii) and (g)(3)(xiii) 

as (g)(3)(xiii) and (g)(3)(xiv), respectively, and adding a new 

paragraph (g)(3)(xii); 
Page 301 of 387 

c. Revising paragraphs (h)(2)(i) and (h)(2)(i)(A) to read 

as follows: 

§63.347 Reporting requirements.

* * * * * 

(g) * * * 

(3) * * * 

(xii) The number, duration, and a brief description for 

each type of malfunction which occurred during the reporting 

period and which caused or may have caused any applicable 

emission limitation to be exceeded. The report must also 

include a description of actions taken by an owner or operator 

during a malfunction of an affected source to minimize emissions 

in accordance with §63.342(a)(1), including actions taken to 

correct a malfunction. 

(xiii) The name, title, and signature of the responsible 

official who is certifying the accuracy of the report; and 

(xiv) The date of the report. 

* * * * * 

(h) * * * 

(2) * * * 

(i) If either of the following conditions is met, 

semiannual reports shall be prepared and submitted to the 

Administrator: 
Page 302 of 387 

(A) The total duration of excess emissions (as indicated 

by the monitoring data collected by the owner or operator of the 

affected source in accordance with §63.343(c)) is 1 percent or 

greater of the total operating time for the reporting period; or 

* * * * * 

8. Table 1 to Subpart KK is amended by: 

a. Removing row 63.7(e); 

b. Adding rows 63.7(e)(1) and 63.7(e)(2)-(4) to read as 

follows: 

Table 1 to Subpart N of Part 63—General Provisions Applicability to Subpart N 

General 

provisions 

reference 

Applies 

to 

subpart N Comment 

* * * * * * * 

63.7(e)(1) No See §63.344(a). Any cross reference to 

§63.7(e)(1) in any other general provision 

incorporated by reference shall be treated 

as a cross-reference to§63.344(a). 

63.7(e)(2)-

(4) 

Yes Subpart N also contains test methods 

specific to affected sources covered by 

that subpart. 

* * * * * * * 

* * * * * 

Subpart U-–[AMENDED] 

9. Section 63.480 is amended by: 

a. Revising paragraph (j) introductory text; 

b. Revising paragraphs (j)(1), (j)(2), and (j)(3); and 

c. Revising paragraph (j)(4) to read as follows: 
Page 303 of 387 

§63.480 Applicability and designation of affected sources. 

* * * * * 

(j) Applicability of this subpart. Paragraphs (j)(1) 

through (4) of this section shall be followed during periods of 

non-operation of the affected source or any part thereof. 

(1) The emission limitations set forth in this subpart and 

the emission limitations referred to in this subpart shall apply 

at all times except during periods of non-operation of the 

affected source (or specific portion thereof) resulting in 

cessation of the emissions to which this subpart applies. 

However, if a period of non-operation of one portion of an 

affected source does not affect the ability of a particular 

emission point to comply with the emission limitations to which 

it is subject, then that emission point shall still be required 

to comply with the applicable emission limitations of this 

subpart during period of non-operation. 

(2) The emission limitations set forth in subpart H of 

this part, as referred to in §63.502, shall apply at all times 

except during periods of non-operation of the affected source 

(or specific portion thereof) in which the lines are drained and 

depressurized resulting in cessation of the emissions to which 

§63.502 applies. 

(3) The owner or operator shall not shut down items of 

equipment that are required or utilized for compliance with this 
Page 304 of 387 

subpart during times when emissions (or, where applicable, 

wastewater streams or residuals) are being routed to such items 

of equipment if the shutdown would contravene requirements of 

this subpart applicable to such items of equipment. 

(4) In response to an action to enforce the standards set 

forth in this subpart, you may assert a civil defense to a claim 

for civil penalties for exceedances of such standards that are 

caused by a malfunction, as defined in 40 CFR 63.2. Appropriate 

penalties may be assessed, however, if the respondent fails to 

meet it’s burden of proving all the requirements in the 

affirmative defense. The affirmative defense shall not be 

available for claims for injunctive relief. 

(i) To establish the affirmative defense in any action to 

enforce such a limit, the owners or operators of facilities must 

timely meet the notification requirements of paragraph (4)(ii) 

of this subsection, and must prove by a preponderance of 

evidence that: 

(A) The excess emissions were caused by a sudden, short, 

infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, or a process to operate in a normal and 

usual manner; and could not have been prevented through careful 

planning, proper design, or better operation and maintenance 

practices; and did not stem from any activity or event that 

could have been foreseen and avoided, or planned for; and were 
Page 305 of 387 

not part of a recurring pattern indicative of inadequate design, 

operation, or maintenance; and 

(B) Repairs were made as expeditiously as possible when 

the applicable emission limitations were being exceeded. Offshift and overtime labor were used, to the extent practicable to 

make these repairs; and 

(C) The frequency, amount, and duration of the excess 

emissions (including any bypass) were minimized to the maximum 

extent practicable during periods of such emissions; and 

(D) If the excess emissions resulted from a bypass of 

control equipment or a process, then the bypass was unavoidable 

to prevent loss of life, severe personal injury, or severe 

property damage; and 

(E) All possible steps were taken to minimize the impact 

of the excess emissions on ambient air quality, the environment, 

and human health; and 

(F) All emissions monitoring and control systems were kept 

in operation if at all possible; and 

(G) Your actions in response to the excess emissions were 

documented by properly signed, contemporaneous operating logs; 

and 

(H) At all times, the facility was operated in a manner 

consistent with good practices for minimizing emissions; and 
Page 306 of 387 

(I) The owner or operator has prepared a written root 

cause analysis to determine, correct, and eliminate the primary 

causes of the malfunction and the excess emissions resulting 

from the malfunction event at issue. The analysis shall also 

specify, using the best monitoring methods and engineering 

judgment, the amount of excess emissions that were the result of 

the malfunction. 

(ii) Notification. The owner or operator of the facility 

experiencing an exceedance of its emission limit(s) during a 

malfunction shall notify the Administrator by telephone or 

facsimile (FAX) transmission as soon as possible, but no later 

than 2 business days after the initial occurrence of the 

malfunction, if it wishes to avail itself of an affirmative 

defense to civil penalties for that malfunction. The owner or 

operator seeking to assert an affirmative defense shall also 

submit a written report to the Administrator within 30 days of 

the initial occurrence of the exceedance of the standard in this 

subpart to demonstrate, with all necessary supporting 

documentation, that it has met the requirements set forth in 

paragraph (4)(i) of this subsection. 

10. Section 63.481 is amended by: 

a. Revising paragraph (c) introductory text; 

b. Adding paragraphs (c)(1) through (c)(4) to read as 

follows: 
Page 307 of 387 

§63.481 Compliance dates and relationship of this subpart to 

existing applicable rules. 

* * * * * 

(c) With the exceptions provided in paragraphs (c)(1) 

through (4) of this section, existing affected sources shall be 

in compliance with this subpart no later than June 19, 2001, as 

provided in §63.6(c), unless an extension has been granted as 

specified in paragraph (e) of this section. 

(1) Existing affected sources producing epichlorohydrin 

elastomer, halobutyl rubber, neoprene rubber, and nitrile 

butadiene rubber shall be in compliance with the applicable 

emission limitation in §63.494(a)(4) no later than 1 year from 

date of publication of the final rule amendments in the Federal 

Register. 

(2) Existing affected sources producing butyl rubber shall 

be in compliance with §63.494(a)(4)(i) no later than 3 years 

from date of publication of the final rule amendments in the 

Federal Register. 

(3) Existing affected sources producing butyl rubber, 

halobutyl rubber, and ethylene propylene rubber shall be in 

compliance with §63.485(q)(1) no later than 3 years from date of 

publication of the final rule amendments in the Federal 

Register. 
Page 308 of 387 

(4) Compliance with §63.502 is covered by paragraph (d) of 

this section. 

* * * * * 

11. Section 63.482 is amended by adding in alphabetical 

order a definition for “affirmative defense,” and revising the 

definition of “initial-startup” in paragraph (b) to read as 

follows: 

§63.482 Definitions. 

* * * * * 

 (b) * * * 

Affirmative defense means, in the context of an enforcement 

proceeding, a response or a defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the 

merits of which are independently and objectively evaluated in a 

judicial or administrative proceeding. 

* * * * * 

 Initial start-up means the first time a new or 

reconstructed affected source begins production of an elastomer 

product, or, for equipment added or changed as described in 

§63.480(i), the first time the equipment is put into operation 

to produce an elastomer product. Initial start-up does not 

include operation solely for testing equipment. Initial startup does not include subsequent start-ups of an affected source 

or portion thereof following shutdowns or following changes in 
Page 309 of 387 

product for flexible operation units or following recharging of 

equipment in batch operation. 

* * * * * 

12. Section 63.483 is amended by adding paragraph (a) to 

read as follows: 

§63.483 Emission standards. 

(a)(1) At all times, each owner or operator must operate 

and maintain any affected source subject to the requirements of 

this subpart, including associated air pollution control 

equipment and monitoring equipment, in a manner consistent with 

safety and good air pollution control practices for minimizing 

emissions. The general duty to minimize emissions does not 

require the owner or operator to make any further efforts to 

reduce emissions if levels required by this standard have been 

achieved. Determination of whether such operation and 

maintenance procedures are being used will be based on 

information available to the Administrator which may include, 

but is not limited to, monitoring results, review of operation 

and maintenance procedures, review of operation and maintenance 

records, and inspection of the source. 

(2) Except as allowed under paragraphs (b) through (d) of 

this section, the owner or operator of an existing or new 

affected source shall comply with the provisions in: 

(i) Section 63.484 for storage vessels; 
Page 310 of 387 

(ii) Section 63.485 for continuous front-end process 

vents; 

(iii) Sections 63.486 through 63.492 for batch front-end 

process vents; 

(iv) Sections 63.493 through 63.500 for back-end process 

operations; 

(v) Section 63.501 for wastewater; 

(vi) Section 63.502 for equipment leaks; 

(vii) Section 63.504 for additional test methods and 

procedures; 

(viii) Section 63.505 for monitoring levels and 

excursions; and 

(ix) Section 63.506 for general reporting and 

recordkeeping requirements. 

* * * * * 

13. Section 63.484 is amended by revising paragraph (b)(4) 

to read as follows: 

§63.484 Storage vessel provisions. 

* * * * * 

 (b) * * * 

(4) Storage vessels located downstream of the stripping 

operations at affected sources subject to the back-end residual 

organic HAP limitation located in §63.494(a)(1) through (3), 

that are complying through the use of stripping technology, as 
Page 311 of 387 

specified in §63.495; 

* * * * * 

14. Section 63.485 is amended by revising paragraphs (q) 

introductory text and (q)(1) to read as follows: 

§63.485 Continuous front-end process vent provisions.

* * * * * 

(q) Group 1 halogenated continuous front-end process vents 

must comply with the provisions of §63.113(a)(1)(ii) and 

§63.113(c), with the exceptions noted in paragraphs (q)(1) and 

(2) of this section. 

(1) All Group 1 and Group 2 halogenated continuous frontend process vents at existing affected sources producing butyl 

rubber, halobutyl rubber, or ethylene propylene rubber using a 

solution process, must comply with §63.113(a)(1)(ii) and 

§63.113(c). 

* * * * * 

15. Section 63.489 is amended by revising paragraph 

(b)(4)(ii)(C) to read as follows: 

§63.489 Batch front-end process vents—monitoring equipment. 

* * * * * 

 (b) * * * 

 (4) * * * 

 (ii) * * * 
Page 312 of 387 

 (C) The owner or operator may prepare and implement a gas 

stream flow determination plan that documents an appropriate 

method which will be used to determine the gas stream flow. The 

plan shall require determination of gas stream flow by a method 

which will at least provide a value for either a representative 

or the highest gas stream flow anticipated in the scrubber 

during representative operating conditions. The plan shall 

include a description of the methodology to be followed and an 

explanation of how the selected methodology will reliably 

determine the gas stream flow, and a description of the records 

that will be maintained to document the determination of gas 

stream flow. The owner or operator shall maintain the plan as 

specified in §63.506(a). 

* * * * * 

16. Section 63.491 is amended by revising paragraph 

(e)(2)(ii) to read as follows: 

§63.491 Batch front-end process vents—recordkeeping 

requirements. 

* * * * * 

 (e) * * * 

 (2) * * * 

 (ii) Monitoring data recorded during periods of monitoring 

system breakdowns, repairs, calibration checks, and zero (lowlevel) and high-level adjustments shall not be included in 
Page 313 of 387 

computing the batch cycle daily averages. In addition, 

monitoring data recorded during periods of non-operation of the 

EPPU (or specific portion thereof) resulting in cessation of 

organic HAP emissions shall not be included in computing the 

batch cycle daily averages. 

* * * * * 

17. Section 63.493 is amended by revising the introductory 

text to read as follows: 

§63.493 Back-end process provisions. 

 Owners and operators of new and existing affected sources 

shall comply with the requirements in §§63.494 through 63.500. 

Owners and operators of affected sources whose only elastomer 

products are latex products, liquid rubber products, or products 

produced in a gas-phased reaction process are not subject to the 

provisions of §§63.494 through 63.500. If latex or liquid 

rubber products are produced in an affected source that also 

produces another elastomer product, the provisions of §§63.494 

through 63.500 do not apply to the back-end operations dedicated 

to the production of one or more latex products or to the backend operations during the production of a latex product. 

18. Section 63.494 is amended by: 

a. Revising the title to §63.494; 

b. Revising paragraph (a) introductory text; 

c. Revising paragraphs (a)(4) and (a)(5); 
Page 314 of 387 

d. Adding paragraph (a)(6); 

e. Revising paragraph (b); 

f. Revising paragraph (c); and 

g. Revising paragraph (d) to read as follows: 

§63.494 Back-end process provisions—residual organic HAP and 

emission limitations. 

 (a) The monthly weighted average residual organic HAP 

content of all grades of styrene butadiene rubber produced by 

the emulsion process, polybutadiene rubber and styrene butadiene 

rubber produced by the solution process, and ethylene-propylene 

rubber produced by the solution process that is processed, shall 

be measured after the stripping operation [or the reactor(s), if 

the plant has no stripper(s)] as specified in §63.495(d), and 

shall not exceed the limits provided in paragraphs (a)(1) 

through (3) of this section, as applicable. Owners or operators 

of these affected sources shall comply with the requirements of 

paragraphs (a)(1) through (3) of this section using either 

stripping technology or control or recovery devices. The 

organic HAP emissions from all back-end process operations at 

affected sources producing butyl rubber, epichlorohydrin 

elastomer, halobutyl rubber, neoprene, and nitrile butadiene 

rubber shall not exceed the limits determined in accordance with 

paragraph (a)(4) of this section, as applicable. 

* * * * * 
Page 315 of 387 

 (4) The organic HAP emissions from back-end processes at 

affected sources producing butyl rubber, epichlorohydrin 

elastomer, halobutyl rubber, neoprene, and nitrile butadiene 

rubber shall not exceed the limits determined in accordance with 

paragraphs (a)(4)(i) through (v) of this section for any 

consecutive 12-month period. The specific limitation for each 

elastomer type shall be determined based on the emissions level 

provided in paragraphs (a)(4)(i) through (v) of this section 

divided by the base year production level. The limitation shall 

be calculated and submitted in accordance with §63.499(f)(1). 

(i) For butyl rubber, the organic HAP emission limitation, 

in units of Mg organic HAP emissions per Mg of butyl rubber 

produced, shall be calculated by dividing 28 Mg/yr by the mass 

of butyl rubber produced in 2009, in Mg. 

(ii) For epichlorohydrin elastomer, the organic HAP 

emission limitation, in units of Mg organic HAP emissions per Mg 

of epichlorohydrin elastomer produced, shall be calculated by 

dividing 36 Mg/yr by the mass of epichlorohydrin elastomer 

produced in 2009, in Mg. 

 (iii) For halobutyl rubber, the organic HAP emission 

limitation, in units of Mg organic HAP emissions per Mg of 

halobutyl rubber produced, shall be calculated by dividing 

53 Mg/yr by the mass of halobutyl rubber produced in 2006, in 

Mg. 
Page 316 of 387 

(iv) For neoprene, the organic HAP emission limitation, in 

units of Mg organic HAP emissions per Mg of neoprene produced, 

shall be calculated by dividing 23 Mg/yr by the mass of neoprene 

produced in 2009, in Mg. 

(v) For nitrile butadiene rubber, the organic HAP emission 

limitation, in units of Mg organic HAP emissions per Mg of 

nitrile butadiene rubber produced, shall be calculated by 

dividing 1.7 Mg/yr by the mass of nitrile butadiene rubber 

produced in 2009, in Mg. 

 (5) For EPPU that produce both an elastomer product with a 

residual organic HAP limitation listed in paragraphs (a)(1) 

through (3) of this section, and a product listed in paragraphs 

(a)(5) (i) through (iv) of this section, only the residual HAP 

content of the elastomer product with a residual organic HAP 

limitation shall be used in determining the monthly average 

residual organic HAP content. 

* * * * * 

 (6) There are no back-end process operation residual 

organic HAP or emission limitations for HypalonTM and polysulfide 

rubber production. There are also no back-end process operation 

residual organic HAP limitations for latex products, liquid 

rubber products, products produced in a gas-phased reaction 

process, styrene butadiene rubber produced by any process other 

than a solution or emulsion process, polybutadiene rubber 
Page 317 of 387 

produced by any process other than a solution process, or 

ethylene-propylene rubber produced by any process other than a 

solution process. 

 (b) If an owner or operator complies with the residual 

organic HAP limitations in paragraph (a)(1) through (3) of this 

section using stripping technology, compliance shall be 

demonstrated in accordance with §63.495. The owner or operator 

shall also comply with the recordkeeping provisions in §63.498, 

and the reporting provisions in §63.499. 

 (c) If an owner or operator complies with the residual 

organic HAP limitations in paragraph (a)(1) through (3) of this 

section using control or recovery devices, compliance shall be 

demonstrated using the procedures in §63.496. The owner or 

operator shall also comply with the monitoring provisions in 

§63.497, the recordkeeping provisions in §63.498, and the 

reporting provisions in §63.499. 

 (d) If the owner or operator complies with the residual 

organic HAP limitations in paragraph (a)(1) through (3) of this 

section using a flare, the owner or operator of an affected 

source shall comply with the requirements in §63.504(c). 

19. Section 63.495 is amended by: 

a. Revising the title to §63.495; 

b. Revising paragraph (a); 

c. Revising paragraph (b)(5); and 
Page 318 of 387 

d. Adding paragraph (g) to read as follows: 

§63.495 Back-end process provisions—procedures to determine 

compliance with residual organic HAP limitations using stripping 

technology and organic HAP emissions limitations. 

 (a) If an owner or operator complies with the residual 

organic HAP limitations in §63.494(a)(1) through (3) using 

stripping technology, compliance shall be demonstrated using the 

periodic sampling procedures in paragraph (b) of this section, 

or using the stripper parameter monitoring procedures in 

paragraph (c) of this section. The owner or operator shall 

determine the monthly weighted average residual organic HAP 

content for each month in which any portion of the back-end of 

an elastomer production process is in operation. A single 

monthly weighted average shall be determined for all back-end 

process operations at the affected source. 

 (b) * * * 

 (5) The monthly weighted average shall be determined using 

the equation in paragraph (f) of this section. All 

representative samples taken and analyzed during the month shall 

be used in the determination of the monthly weighted average. 

* * * * * 

(g) Compliance with the organic HAP emission limitations 

determined in accordance with §63.494(a)(4) shall be 

demonstrated in accordance with paragraphs (g)(1) through (5) of 
Page 319 of 387 

this section. 

(1) Calculate your organic HAP emission limitation in 

accordance with §63.494(a)(4)(i) through (v), as applicable, 

record it, and submit it in accordance with §63.499(f)(1). 

(2) Each month, calculate and record the organic HAP 

emissions from all back end process operations using engineering 

assessment. Engineering assessment includes, but is not limited 

to, the following: 

(i) Previous test results, provided the test was 

representative of current operating practices. 

(ii) Bench-scale or pilot-scale test data obtained under 

conditions representative of current process operating 

conditions. 

 (iii) Design analysis based on accepted chemical 

engineering principles, measurable process parameters, or 

physical or chemical laws or properties. Examples of analytical 

methods include, but are not limited to: 

(A) Use of material balances; 

(B) Estimation of flow rate based on physical equipment 

design, such as pump or blower capacities; 

(C) Estimation of organic HAP concentrations based on 

saturation conditions; and 

(D) Estimation of organic HAP concentrations based on grab 

samples of the liquid or vapor. 
Page 320 of 387 

(3) Each month, record the mass of elastomer product 

produced. 

(4) Each month, calculate and record the sums of the 

organic HAP emissions and the mass of elastomer produced for the 

month and the previous 11 months. 

(5) Each month, divide the total mass of organic HAP 

emitted for the 12-month period by the total mass of elastomer 

produced during the 12-month period. This value must be 

recorded in accordance with §63.498(e) and reported in 

accordance with §63.499(f)(2). 

20. Section 63.496 is amended by: 

a. Revising the title to §63.496; 

b. Revising paragraph (a); 

c. Revising paragraph (c)(2); and 

d. Revising paragraph (d) to read as follows: 

§63.496 Back-end process provisions—procedures to determine 

compliance with residual organic HAP limitations using control 

or recovery devices. 

(a) If an owner or operator complies with the residual 

organic HAP limitations in §63.494(a)(1) through (3) using 

control or recovery devices, compliance shall be demonstrated 

using the procedures in paragraphs (b) and (c) of this section. 

Previous test results conducted in accordance with paragraphs 

(b)(1) through (6) of this section may be used to determine 
Page 321 of 387 

compliance in accordance with paragraph (c) of this section. 

* * * * * 

 (c) * * * 

 (2) A facility is in compliance if the average of the 

organic HAP contents calculated for all three test runs is below 

the residual organic HAP limitations in §63.494(a)(1) through 

(3). 

(d) An owner or operator complying with the residual 

organic HAP limitations in §63.494(a)(1) through (3) using a 

control or recovery device, shall redetermine the compliance 

status through the requirements described in paragraph (b) of 

this section whenever process changes are made. The owner or 

operator shall report the results of the redetermination in 

accordance with §63.499(d). For the purposes of this section, a 

process change is any action that would reasonably be expected 

to impair the performance of the control or recovery device. 

For the purposes of this section, the production of an elastomer 

with a residual organic HAP content greater than the residual 

organic HAP content of the elastomer used in the compliance 

demonstration constitutes a process change, unless the overall 

effect of the change is to reduce organic HAP emissions from the 

source as a whole. Other examples of process changes may 

include changes in production capacity or production rate, or 

removal or addition of equipment. For the purposes of this 
Page 322 of 387 

paragraph, process changes do not include: Process upsets; 

unintentional, temporary process changes; or changes that reduce 

the residual organic HAP content of the elastomer. 

21. Section 63.497 is amended by: 

a. Revising the title to §63.497; 

b. Revising paragraph (a) introductory text; and 

c. Revising paragraph (d) introductory text to read as 

follows: 

§63.497 Back-end process provisions—monitoring provisions for 

control and recovery devices used to comply with residual 

organic HAP limitations.

(a) An owner or operator complying with the residual 

organic HAP limitations in §63.494(a)(1) through (3) using 

control or recovery devices, or a combination of stripping and 

control or recovery devices, shall install the monitoring 

equipment specified in paragraphs (a)(1) through (6) of this 

section, as appropriate. 

* * * * * 

(d) The owner or operator of an affected source with a 

controlled back-end process vent using a vent system that 

contains bypass lines that could divert a vent stream away from 

the control or recovery device used to comply with §63.494(a)(1) 

through (3) shall comply with paragraph (d)(1) or (2) of this 

section. Equipment such as low leg drains, high point bleeds, 
Page 323 of 387 

analyzer vents, open-ended valves or lines, and pressure relief 

valves needed for safety purposes are not subject to this 

paragraph. 

* * * * * 

22. Section 63.498 is amended by: 

a. Revising paragraph (a) introductory text; 

b. Revising paragraph (a)(3); 

c. Adding paragraph (a)(4); 

d. Revising paragraph (b) introductory text; 

e. Revising paragraph (b)(3); 

f. Revising paragraph (c) introductory text; 

g. Revising paragraph (d) introductory text; 

h. Revising paragraph (d)(5)(ii)(B); 

i. Revising paragraph (d)(5)(ii)(E); and 

j. Adding paragraph (e) to read as follows: 

§63.498 Back-end process provisions—recordkeeping. 

 (a) Each owner or operator shall maintain the records 

specified in paragraphs (a)(1) through (3), and paragraphs (b) 

through (d) of this section, as appropriate. 

* * * * * 

 (3) If the back-end process operation is subject to a 

residual organic HAP limitation in §63.494(a)(1) through (3), 

whether compliance will be achieved by stripping technology, or 

by control or recovery devices. 
Page 324 of 387 

(4) If the back-end process operation is subject to an 

emission limitation in §63.494(a)(4), the organic HAP emission 

limitation calculated in accordance with §63.494(a)(4)(i) 

through (v), as applicable. 

 (b) Each owner or operator of a back-end process operation 

using stripping technology to comply with a residual organic HAP 

limitation in §63.494(a)(1) through (3), and demonstrating 

compliance using the periodic sampling procedures in §63.495(b), 

shall maintain the records specified in paragraph (b)(1), and in 

paragraph (b)(2) or paragraph (b)(3) of this section, as 

appropriate. 

* * * * * 

 (3) If the organic HAP contents for all samples analyzed 

during a month are below the appropriate level in §63.494(a), 

the owner or operator may record that all samples were in 

accordance with the residual organic HAP limitations in 

§63.494(a)(1) through (3), rather than calculating and recording 

a monthly weighted average. 

 (c) Each owner or operator of a back-end process operation 

using stripping technology to comply with a residual organic HAP 

limitation in §63.494(a)(1) through (3), and demonstrating 

compliance using the stripper parameter monitoring procedures in 

§63.495(c), shall maintain the records specified in paragraphs 

(c)(1) through (3) of this section. 
Page 325 of 387 

* * * * * 

 (d) Each owner or operator of a back-end process operation 

using control or recovery devices to comply with a residual 

organic HAP limitation in §63.494(a)(1) through (3) shall 

maintain the records specified in paragraphs (d)(1) through (5) 

of this section. The recordkeeping requirements contained in 

paragraphs (d)(1) through (4) pertain to the results of the 

testing required by §63.496(b), for each of the three required 

test runs. 

* * * * * 

 (5) * * * 

 (ii) * * * 

 (B) Monitoring data recorded during periods of monitoring 

system breakdowns, repairs, calibration checks, and zero (lowlevel) and high-level adjustments shall not be included in 

computing the hourly or daily averages. In addition, monitoring 

data recorded during periods of non-operation of the EPPU (or 

specific portion thereof) resulting in cessation of organic HAP 

emissions shall not be included in computing the hourly or daily 

averages. Records shall be kept of the times and durations of 

all such periods and any other periods of process or control 

device operation when monitors are not operating. 

* * * * * 
Page 326 of 387 

 (E) For flares, records of the times and duration of all 

periods during which the pilot flame is absent shall be kept 

rather than daily averages. The records specified in this 

paragraph are not required during periods when emissions are not 

routed to the flare. 

* * * * * 

(e) If the back-end process operation is subject to an 

organic HAP emission limitation in §63.494(a)(4), the records 

specified in paragraphs (e)(1) through (4) of this section. 

(1) The applicable organic HAP emission limitation determined 

in accordance with §63.494(a)(4)(i) through (v). 

(2) The organic HAP emissions from all back-end process 

operations for each month, along with documentation of all 

calculations and other information used in the engineering 

assessment to estimate these emissions. 

(3) The mass of elastomer product produced each month. 

(4) The total mass of organic HAP emitted for each 12-month 

period divided by the total mass of elastomer produced during 

the 12-month period, determined in accordance with 

§63.495(g)(5). 

23. Section 63.499 is amended by: 

a. Revising paragraph (a)(3); 

b. Revising paragraph (b) introductory text; 

c. Revising paragraph (c) introductory text; 
Page 327 of 387 

d. Revising paragraph (d) introductory text; and 

e. Adding paragraph (f) to read as follows: 

§63.499 Back-end process provisions—reporting. 

 (a) * * * 

 (3) If the back-end process operation is subject to a 

residual organic HAP limitation in §63.494(a)(1) through (3), 

whether compliance will be achieved by stripping technology, or 

by control or recovery devices. 

(b) Each owner or operator of a back-end process operation 

using stripping to comply with a residual organic HAP limitation 

in §63.494(a)(1) through (3), and demonstrating compliance by 

stripper parameter monitoring, shall submit reports as specified 

in paragraphs (b)(1) and (2) of this section. 

* * * * * 

(c) Each owner or operator of an affected source with a 

back-end process operation control or recovery device that shall 

comply with a residual organic HAP limitation in §63.494(a)(1) 

through (3) shall submit the information specified in paragraphs 

(c)(1) through (3) of this section as part of the Notification 

of Compliance Status specified in §63.506(e)(5). 

* * * * * 

(d) Whenever a process change, as defined in §63.496(d), 

is made that causes the redetermination of the compliance status 

for the back-end process operations subject to a residual 
Page 328 of 387 

organic HAP limitation in §63.494(a)(1) through (3), the owner 

or operator shall submit a report within 180 days after the 

process change, as specified in §63.506(e)(7)(iii). The report 

shall include: 

* * * * * 

 (f) If the back-end process operation is subject to an 

organic HAP emission limitation in §63.494(a)(4), the owner and 

operator must submit the information specified in paragraphs 

(f)(1) and (2) of this section. 

(1) The applicable organic HAP emission limitation 

determined in accordance with §63.494(a)(4)(i) through (v) shall 

be submitted no later than 180 days from the date of publication 

of the final rule amendments in the Federal Register. 

(2) In the periodic report required to be submitted by 

§63.506(e)(6), the total mass of organic HAP emitted for each of 

the rolling 12-month periods in the reporting period divided by 

the total mass of elastomer produced during the corresponding 

12-month period, determined in accordance with §63.495(g)(5). 

24. Section 63.501 is amended by revising paragraph (c)(2) 

to read as follows: 

§63.501 Wastewater provisions. 

* * * * * 

 (c) * * * 

 (2) Back-end streams at affected sources that are subject 
Page 329 of 387 

to a residual organic HAP limitation in §63.494(a)(1) through 

(3) and that are complying with these limitations through the 

use of stripping technology. 

25. Section 63.502 is amended by revising paragraph (b)(4) 

to read as follows: 

§63.502 Equipment leak and heat exchange system provisions. 

* * * * * 

 (b) * * * 

 (4) Surge control vessels and bottoms receivers located 

downstream of the stripping operations at affected sources 

subject to the back-end residual organic HAP limitation located 

in §63.494(a)(1) through (3), that are complying through the use 

of stripping technology, as specified in §63.495; 

* * * * * 

26. Section 63.503 is amended by removing and reserving 

paragraph (f)(1) to read as follows: 

§63.503 Emissions averaging provisions. 

* * * * * 

 (f) * * * 

 (1) [Reserved] 

* * * * * 

27. Section 63.504 is amended by revising paragraph (a)(1) 

to read as follows: 

§63.504 Additional requirements for performance testing. 
Page 330 of 387 

(a) * * * 

(1) Performance tests shall be conducted at maximum 

representative operating conditions achievable during one of the 

time periods described in paragraph (a)(1)(i) of this section, 

without causing any of the situations described in paragraph 

(a)(1)(ii) of this section to occur. Upon request, the owner or 

operator shall make available to the Administrator such records 

as may be necessary to determine the conditions of performance 

tests. 

* * * * * 

28. Section 63.505 is amended by: 

a. Revising paragraph (e)(4); 

b. Revising paragraph (g)(1)(v)(A); 

c. Revising paragraph (g)(1)(v)(B); 

d. Removing paragraphs (g)(1)(v)(C) through (g)(1)(v)(E); 

e. Revising paragraph (g)(2)(ii)(B); 

f. Removing paragraphs (g)(2)(ii)(B)(1)-(4); and 

g. Adding paragraph (j) to read as follows: 

§63.505 Parameter monitoring levels and excursions. 

* * * * * 

 (e) * * * 

 (4) An owner or operator complying with the residual 

organic HAP limitations in paragraphs (a)(1) through (3) of 

§63.494 using stripping, and demonstrating compliance by 
Page 331 of 387 

stripper parameter monitoring, shall redetermine the residual 

organic HAP content for all affected grades whenever process 

changes are made. For the purposes of this section, a process 

change is any action that would reasonably be expected to impair 

the performance of the stripping operation. For the purposes of 

this section, examples of process changes may include changes in 

production capacity or production rate, or removal or addition 

of equipment. For purposes of this paragraph, process changes 

do not include: Process upsets; unintentional, temporary 

process changes; or changes that reduce the residual organic HAP 

content of the elastomer. 

* * * * * 

 (g) * * * 

 (1) * * * 

 (v) * * * 

 (A) Monitoring system breakdowns, repairs, calibration 

checks, and zero (low-level) and high-level adjustments; or 

 (B) Periods of non-operation of the affected source (or 

portion thereof), resulting in cessation of the emissions to 

which the monitoring applies. 

 (2) * * * 

 (ii) * * * 

 (B) Subtract the time during the periods of monitoring 

system breakdowns, repairs, calibration checks, and zero (low-
Page 332 of 387 

level) and high-level adjustments from the total amount of time 

determined in paragraph (g)(2)(ii)(A) of this section, to obtain 

the operating time used to determine if monitoring data are 

insufficient. 

* * * * * 

(j) Excursion definition for back-end operations subject 

to §63.494(a)(4). An excursion means when the total mass of 

organic HAP emitted for any consecutive 12-month period divided 

by the total mass of elastomer produced during the 12-month 

period, determined in accordance with §63.495(g), is greater 

than the applicable emission limitation, determined in 

accordance with §63.494(a)(4)(i) through (v) and submitted in 

accordance with §63.499(f)(1). 

29. Section 63.506 is amended by: 

a. Revising paragraph (b)(1); 

b. Removing paragraphs (b)(1)(i), (b)(1)(i)(A), and 

(b)(1)(i)(B); 

c. Removing paragraph (b)(1)(ii); 

d. Revising paragraph (d)(7) introductory text; 

e. Revising paragraphs (d)(7)(i) and (d)(7)(ii); 

f. Removing paragraphs (d)(7)(iii) through (d)(7)(v); 

g. Revising paragraph (e)(3); 

h. Removing and reserving paragraph (e)(3)(viii); 
Page 333 of 387 

i. Removing paragraphs (e)(3)(viii)(A) and 

(e)(3)(viii)(B); 

j. Revising paragraph (e)(3)(ix)(B); 

k. Revising paragraph (e)(6)(iii)(E); 

l. Revising paragraph (h)(1)(i); 

m. Revising paragraph (h)(1)(ii)(C); 

n. Revising paragraph (h)(1)(iii); 

o. Revising paragraph (h)(2)(iii); and 

p. Removing and reserving paragraph (h)(2)(iv)(A) to read 

as follows: 

§63.506 General recordkeeping and reporting provisions. 

* * * * * 

(b) * * * 

(1) Malfunction records. Each owner or operator of an 

affected source subject to this subpart shall maintain records 

of the occurrence and duration of each malfunction of operation 

(i.e., process equipment), air pollution control equipment, or 

monitoring equipment. Each owner or operator shall maintain 

records of actions taken during periods of malfunction to 

minimize emissions in accordance with §63.483(a)(1), including 

corrective actions to restore malfunctioning process and air 

pollution control and monitoring equipment to its normal or 

usual manner of operation. 

* * * * * 
Page 334 of 387 

 (d) * * * 

(7) Monitoring data recorded during periods identified in 

paragraphs (d)(7)(i) and (ii) of this section shall not be 

included in any average computed under this subpart. Records 

shall be kept of the times and durations of all such periods and 

any other periods during process or control device or recovery 

device operation when monitors are not operating. 

(i) Monitoring system breakdowns, repairs, calibration 

checks, and zero (low-level) and high-level adjustments; or 

(ii) Periods of non-operation of the affected source (or 

portion thereof), resulting in cessation of the emissions to 

which the monitoring applies. 

* * * * * 

(e) * * * 

(3) Precompliance Report. Owners or operators of affected 

sources requesting an extension for compliance; requesting 

approval to use alternative monitoring parameters, alternative 

continuous monitoring and recordkeeping, or alternative 

controls; requesting approval to use engineering assessment to 

estimate emissions from a batch emissions episode, as described 

in §63.488(b)(6)(i); wishing to establish parameter monitoring 

levels according to the procedures contained in §63.505(c) or 

(d); shall submit a Precompliance Report according to the 

schedule described in paragraph (e)(3)(i) of this section. The 
Page 335 of 387 

Precompliance Report shall contain the information specified in 

paragraphs (e)(3)(ii) through (vii) of this section, as 

appropriate. 

* * * * * 

(viii) [Reserved] 

(ix) * * * 

(B) Supplements to the Precompliance Report may be 

submitted to request approval to use alternative monitoring 

parameters, as specified in paragraph (e)(3)(iii) of this 

section; to use alternative continuous monitoring and 

recordkeeping, as specified in paragraph (e)(3)(iv) of this 

section; to use alternative controls, as specified in paragraph 

(e)(3)(v) of this section; to use engineering assessment to 

estimate emissions from a batch emissions episode, as specified 

in paragraph (e)(3)(vi) of this section; or to establish 

parameter monitoring levels according to the procedures 

contained in §63.505(c) or (d), as specified in paragraph 

(e)(3)(vii) of this section. 

* * * * * 

(6) * * * 

(iii) * * * 

(E) The number, duration, and a brief description for each 

type of malfunction which occurred during the reporting period 

and which caused or may have caused any applicable emission 
Page 336 of 387 

limitation to be exceeded. The report must also include a 

description of actions taken by an owner or operator during a 

malfunction of an affected source to minimize emissions in 

accordance with §63.483(a)(1), including actions taken to 

correct a malfunction. 

* * * * * 

(h) * * * 

(1) * * * 

(i) The monitoring system is capable of detecting 

unrealistic or impossible data during periods of normal 

operation (e.g., a temperature reading of −200 °C on a boiler), 

and will alert the operator by alarm or other means. The owner 

or operator shall record the occurrence. All instances of the 

alarm or other alert in an operating day constitute a single 

occurrence. 

(ii) * * * 

(C) The running average reflects a period of normal 

operation. 

(iii) The monitoring system is capable of detecting 

unchanging data during periods of normal operation, except in 

circumstances where the presence of unchanging data is the 

expected operating condition based on past experience (e.g., pH 

in some scrubbers), and will alert the operator by alarm or 

other means. The owner or operator shall record the occurrence. 
Page 337 of 387 

All instances of the alarm or other alert in an operating day 

constitute a single occurrence. 

* * * * * 

(2) * * * 

(iii) The owner or operator shall retain the records 

specified in paragraphs (h)(1)(i) through (iii) of this section, 

for the duration specified in paragraph (h) of this section. 

For any calendar week, if compliance with paragraphs (h)(1)(i) 

through (iii) of this section does not result in retention of a 

record of at least one occurrence or measured parameter value, 

the owner or operator shall record and retain at least one 

parameter value during a period of normal operation. 

(iv) * * * 

(A) [Reserved] 

* * * * * 

30. Table 1 to Subpart U of part 63 is amended by: 

a. Removing row 63.6(e); 

b. Revising rows 63.6(e)(1)(i) and 63.6(e)(1)(ii); 

c. Revising row 63.6(e)(2); 

d. Adding row 63.6(e)(3); 

e. Removing rows 63.6(e)(3)(i) through 63.6(e)(3)(ix); 

f. Revising row 63.6(f)(1); and 

e. Revising rows 63.10(d)(5)(i) and 63.10(d)(5)(ii) to 

read as follows: 
Page 338 of 387 

TABLE 1 TO SUBPART U OF PART 63—APPLICABILITY OF GENERAL 

PROVISIONS TO SUBPART U AFFECTED SOURCES 

Reference Applies to subpart U Explanation 

* * * * * * * 

§63.6(e)(1)(i) No See §63.483(a)(1) 

for general duty 

requirement. Any 

cross reference to 

§63.6(e)(1)(i) in 

any other general 

provision 

incorporated by 

reference shall be 

treated as a cross 

reference to 

§63.483(a)(1). 

§63.6(e)(1)(ii) No 

* * * * * * * 

§63.6(e)(2) No [Reserved.]. 

§63.6(e)(3) No 

§63.6(f)(1) No 

* * * * * * * 

§63.7(e)(1) No 

See §63.504(a)(1). 

Any crossreference to 

§63.7(e)(1) in any 

other general 

provision 
Page 339 of 387 

incorporated by 

reference shall be 

treated as a 

cross-reference to 

§63.504(a)(1). 

* * * * * * * 

63.10(d)(5)(i) No 

* * * * * * * 

Subpart Y-–[AMENDED] 

31. Section 63.560 is amended by: 

a. Revising paragraphs (a)(1), (a)(2), and (a)(3); 

b. Revising paragraph (d)(6) introductory text; 

d. Adding paragraphs (d)(6)(i) and (d)(6)(ii); and 

e. Revising paragraph (e)(1)(iv) to read as follows: 

§63.560 Applicability and designation of affected source. 

 (a) * * * 

(1) The provisions of this subpart pertaining to the MACT 

standards in §63.562(b) and (d) of this subpart are applicable 

to existing and new sources with emissions of 10 or 25 tons, as 

that term is defined in §63.561, except as specified in 

paragraph (d) of this section, and are applicable to new sources 

with emissions less than 10 and 25 tons, as that term is defined 

in §63.561, except as specified in paragraphs (d) and (f) of 
Page 340 of 387 

this section. 

(2) Existing sources with emissions less than 10 and 25 

tons are not subject to the emissions standards in §63.562(b) 

and (d), except as specified in paragraph (f) of this section. 

(3) The recordkeeping requirements of §63.567(j)(4) and 

the emission estimation requirements of §63.565(l) apply to 

existing sources with emissions less than 10 and 25 tons, except 

as specified in paragraph (f) of this section. 

* * * * * 

(d) * * * 

(6) The provisions of this subpart do not apply to marine 

tank vessel loading operations at existing offshore loading 

terminals, as that term is defined in §63.561, except existing 

offshore loading terminals must meet (d)(6)(i) and (ii) of this 

section. 

(i) The submerged fill standards of 46 CFR 153.282, and 

(ii) The provisions of §63.562(f)(1) or §63.562(f)(2), if 

the terminal loads more than 1 million barrels (M barrels) of 

gasoline. 

* * * * * 

(e) * * * 

(1) * * * 

(iv) New and existing sources with emissions less than 10 or 

25 tons, that load more than 1 M barrels of gasoline shall 
Page 341 of 387 

comply with the provisions of §63.562(f) by [insert date 3 years 

after date of proposal]. 

* * * * * 

 32. Table 1 to §63.560 is amended by: 

a. Revising row 63.6(f)(1); 

b. Removing row 63.7(e); 

c. Adding rows 63.7(e)(1) and 63.7(e)(2)-(4); 

d. Removing row 63.10(b)(2)(ii)-(iii); 

e. Adding rows 63.10(b)(2)(ii) and 63.10(b)(2)(iii); 

f. Removing row 63.10(c)(10)-(13); and 

g. Adding rows 63.10(c)(10)-(11) and 63.10(c)(12)-(13) 

to read as follows:

Table 1 of §63.560—General Provisions Applicability to Subpart Y 

Reference 

Applies to 

affected 

sources in 

subpart Y 

Comment 

* * * * * * * 

63.6(f)(1) No 

* * * * * * * 

63.7(e)(1) No 

See 63.563(b)(1). Any cross 

reference to 63.7(e)(1) in any other 

general provision incorporated by 

reference shall be treated as a 

cross-reference to 63.563(b)(1). 

63.7(e)(2)-(4) Yes 

* * * * * * * 

63.10(b)(2)(iii) Yes 

* * * * * * * 

63.10(c)(10)–

(11) No See 63.567(m)(1) for reporting 

malfunctions. Any cross-reference to 
Page 342 of 387 

63.10(c)(10) or 63.10(c)(11) in any 

other general provision incorporated 

by reference shall be treated as a 

cross-reference to 63.567(m)(1). 

63.10(c)(12)–

(13) Yes 

* * * * * * * 

33. Section 63.561 is amended by adding in alphabetical 

order a definition for “affirmative defense” to read as follows: 

§63.561 Definitions. 

* * * * * 

Affirmative defense means, in the context of an enforcement 

proceeding, a response or a defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the 

merits of which are independently and objectively evaluated in a 

judicial or administrative proceeding. 

* * * * * 

34. Section 63.562 is amended by: 

a. Revising paragraph (a); 

b. Revising paragraph (b)(1); 

c. Revising paragraph (e); 

d. Adding paragraph (e)(7); and 

e. Adding paragraph (f) to read as follows: 

§63.562 Standards. 

(a) The emissions limitations in paragraphs (b), (c), (d) 

and (f) of this section apply during marine tank vessel loading 
Page 343 of 387 

operations. 

 (b) MACT standards, except for the VMT source--(1)(i) Vapor 

collection system of the terminal. The owner or operator of a 

new source with emissions less than 10 and 25 tons, an existing 

or new source with emissions of 10 or 25 tons, and an existing 

source with emissions less than 10 and 25 tons that loads more 

than 1 M barrels of gasoline shall equip each terminal with a 

vapor collection system that is designed to collect HAP vapors 

displaced from marine tank vessels during marine tank vessel 

loading operations and to prevent HAP vapors collected at one 

loading berth from passing through another loading berth to the 

atmosphere, except for those commodities exempted under 

§63.560(d). 

 (ii) Ship-to-shore compatibility. The owner or operator of 

a new source with emissions less than 10 and 25 tons, an 

existing or new source with emissions of 10 or 25 tons, and an 

existing source with emissions less than 10 and 25 tons that 

loads more than 1 million bbl/yr of gasoline shall limit marine 

tank vessel loading operations to those vessels that are 

equipped with vapor collection equipment that is compatible with 

the terminal's vapor collection system, except for those 

commodities exempted under §63.560(d). 

 (iii) Vapor tightness of marine vessels. The owner or 

operator of a new source with emissions less than 10 and 25 
Page 344 of 387 

tons, an existing or new source with emissions of 10 or 25 tons, 

and an existing source with emissions less than 10 and 25 tons 

that loads more than 1 million bbl/yr of gasoline shall limit 

marine tank vessel loading operations to those vessels that are 

vapor tight and to those vessels that are connected to the vapor 

collection system, except for those commodities exempted under 

§63.560(d). 

* * * * * 

 (e) Operation and maintenance requirements for air pollution 

control equipment and monitoring equipment for affected sources. 

At all times, owners or operators of affected sources shall 

operate and maintain a source, including associated air 

pollution control equipment, in a manner consistent with safety 

and good air pollution control practices for minimizing 

emissions. Determination of whether acceptable operation and 

maintenance procedures are being used will be based on 

information available to the Administrator which may include, 

but is not limited to, monitoring results, review of operation 

and maintenance procedures, review of operation and maintenance 

records, and inspection of the source. 

* * * * * 

(7) In response to an action to enforce the standards set 

forth in this subpart, you may assert a civil defense to a claim 

for civil penalties for exceedances of such standards that are 
Page 345 of 387 

caused by a malfunction, as defined in §63.2. Appropriate 

penalties may be assessed, however, if the respondent fails to 

meet it’s burden of proving all the requirements in the 

affirmative defense. The affirmative defense shall not be 

available for claims for injunctive relief. 

(i) To establish the affirmative defense in any action to 

enforce such a limit, the owners or operators of facilities must 

timely meet the notification requirements of paragraph (7)(ii) 

of this subsection, and must prove by a preponderance of 

evidence that: 

(A) The excess emissions were caused by a sudden, short, 

infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, or a process to operate in a normal an 

usual manner; and could not have been prevented through careful 

planning, proper design or better operation and maintenance 

practices; and did not stem from any activity or event that 

could have been foreseen and avoided, or planned for; and were 

not part of a recurring pattern indicative of inadequate design, 

operation, or maintenance; and 

(B) Repairs were made as expeditiously as possible when 

the applicable emission limitations were being exceeded. Offshift and overtime labor were used, to the extent practicable to 

make these repairs; and 
Page 346 of 387 

(C) The frequency, amount and duration of the excess 

emissions (including any bypass) were minimized to the maximum 

extent practicable during periods of such emissions; and 

(D) If the excess emissions resulted from a bypass of 

control equipment or a process, then the bypass was unavoidable 

to prevent loss of life, severe personal injury, or severe 

property damage; and 

(E) All possible steps were taken to minimize the impact 

of the excess emissions on ambient air quality, the environment, 

and human health; and 

(F) All emissions monitoring and control systems were kept 

in operation if at all possible; and 

(G) Your actions in response to the excess emissions were 

documented by properly signed, contemporaneous operating logs; 

and 

(H) At all times, the facility was operated in a manner 

consistent with good practices for minimizing emissions; and 

(I) The owner or operator has prepared a written root 

cause analysis to determine, correct and eliminate the primary 

causes of the malfunction and the excess emissions resulting 

from the malfunction event at issue. The analysis shall also 

specify, using the best monitoring methods and engineering 

judgment, the amount of excess emissions that were the result of 

the malfunction. 
Page 347 of 387 

 (ii) Notification. The owner or operator of the facility 

experiencing an exceedance of its emission limit(s) during a 

malfunction shall notify the Administrator by telephone or 

facsimile (FAX) transmission as soon as possible, but no later 2 

business days after the initial occurrence of the malfunction, 

if it wishes to avail itself of an affirmative defense to civil 

penalties for that malfunction. The owner or operator seeking 

to assert an affirmative defense shall also submit a written 

report to the Administrator within 30 days of the initial 

occurrence of the exceedance of the standard in this subpart to 

demonstrate, with all necessary supporting documentation, that 

it has met the requirements set forth in paragraph (7)(i) of 

this subsection. 

 (f) The owner or operator of an existing source, that is 

not located at a petroleum refinery, with emissions less than 10 

and 25 tons that loads more than 1 million bbl/yr of gasoline 

shall: 

 (1) Limit emissions to not more than 10 mg of total organic 

compounds per liter of gasoline loaded; or 

 (2) Reduce captured emissions by at least 98 percent by 

weight. 

35. Section 63.563 is amended by revising paragraphs (a) 

and (b)(1) to read as follows: 

§63.563 Compliance and performance testing. 
Page 348 of 387 

(a) The following procedures shall be used to determine 

compliance with the emissions limits under Sec. 63.562(b)(1), 

(c)(2), (d)(1), and (f): 

* * * * * 

(b) * * * 

(1) Initial performance test. An initial performance test 

shall be conducted using the procedures listed in §63.7 of 

subpart A of this part according to the applicability in Table 1 

of §63.560, the procedures listed in this section, and the test 

methods listed in §63.565. The initial performance test shall 

be conducted within 180 days after the compliance date for the 

specific affected source. During this performance test, sources 

subject to MACT standards under §63.562(b)(2), (3), (4), and 

(5), and (d)(2) shall determine the reduction of HAP emissions, 

as VOC, for all combustion or recovery devices other than 

flares. Performance tests shall be conducted under such 

conditions as the Administrator specifies to the owner or 

operator based on representative performance of the affected 

source for the period being tested. Upon request, the owner or 

operator shall make available to the Administrator such records 

as may be necessary to determine the conditions of performance 

tests. Sources subject to RACT standards under §63.562(c)(3), 

(4), and (5), and (d)(2) shall determine the reduction of VOC 
Page 349 of 387 

emissions for all combustion or recovery devices other than 

flares. 

* * * * * 

SUBPART KK—[AMENDED] 

 36. Section 63.820 is amended by adding paragraph (c) to 

read as follows: 

§63.820 Applicability. 

* * * * * 

(c) In response to an action to enforce the standards set 

forth in this subpart, you may assert a civil defense to a claim 

for civil penalties for exceedances of such standards that are 

caused by a malfunction, as defined in §63.2. Appropriate 

penalties may be assessed, however, if the respondent fails to 

meet its burden of proving all the requirements in the 

affirmative defense. The affirmative defense shall not be 

available for claims for injunctive relief. 

(1) To establish the affirmative defense in any action to 

enforce such a limit, the owners or operators of facilities must 

timely meet the notification requirements of paragraph (c)(2) of 

this subsection, and must prove by a preponderance of evidence 

that: 

(i) The excess emissions were caused by a sudden, short, 

infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, or a process to operate in a normal an 
Page 350 of 387 

usual manner; and could not have been prevented through careful 

planning, proper design or better operation and maintenance 

practices; and did not stem from any activity or event that 

could have been foreseen and avoided, or planned for; and were 

not part of a recurring pattern indicative of inadequate design, 

operation, or maintenance; and 

(ii) Repairs were made as expeditiously as possible when 

the applicable emission limitations were being exceeded. Offshift and overtime labor were used, to the extent practicable to 

make these repairs; and 

(iii) The frequency, amount, and duration of the excess 

emissions (including any bypass) were minimized to the maximum 

extent practicable during periods of such emissions; and 

(iv) If the excess emissions resulted from a bypass of 

control equipment or a process, then the bypass was unavoidable 

to prevent loss of life, severe personal injury, or severe 

property damage; and 

(v) All possible steps were taken to minimize the impact 

of the excess emissions on ambient air quality, the environment, 

and human health; and 

(vi) All emissions monitoring and control systems were 

kept in operation if at all possible; and 
Page 351 of 387 

(vii) Your actions in response to the excess emissions 

were documented by properly signed, contemporaneous operating 

logs; and 

(viii) At all times, the facility was operated in a manner 

consistent with good practices for minimizing emissions; and 

(ix) The owner or operator has prepared a written root 

cause analysis to determine, correct and eliminate the primary 

causes of the malfunction and the excess emissions resulting 

from the malfunction event at issue. The analysis shall also 

specify, using the best monitoring methods and engineering 

judgment, the amount of excess emissions that were the result of 

the malfunction. 

(2) Notification. The owner or operator of the facility 

experiencing an exceedance of its emission limit(s) during a 

malfunction shall notify the Administrator by telephone or 

facsimile (FAX) transmission as soon as possible, but no later 2 

business days after the initial occurrence of the malfunction, 

if it wishes to avail itself of an affirmative defense to civil 

penalties for that malfunction. The owner or operator seeking 

to assert an affirmative defense shall also submit a written 

report to the Administrator within 30 days of the initial 

occurrence of the exceedance of the standard in this subpart to 

demonstrate, with all necessary supporting documentation, that 

it has met the requirements set forth in paragraph (c)(1) of 
Page 352 of 387 

this subsection. 

 37. Section 63.822 is amended by adding in alphabetical 

order a definition for “affirmative defense” to paragraph (a) to 

read as follows: 

§63.822 Definitions. 

(a) * * * 

Affirmative defense means, in the context of an enforcement 

proceeding, a response or a defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the 

merits of which are independently and objectively evaluated in a 

judicial or administrative proceeding. 

* * * * *

38. Section 63.823 is amended by: 

 a. Removing introductory text; and 

 b. Adding paragraphs (a) and (b) to read as follows: 

§63.823 Standards: General. 

(a) Table 1 to this subpart provides cross references to 

the 40 CFR part 63, subpart A, general provisions, indicating 

the applicability of the general provisions requirements to this 

subpart KK. 

 (b) Each owner or operator of an affected source subject 

to this subpart must at all times operate and maintain that 

affected source, including associated air pollution control 

equipment and monitoring equipment, in a manner consistent with 
Page 353 of 387 

safety and good air pollution control practices for minimizing 

emissions. Determination of whether such operation and 

maintenance procedures are being used will be based on 

information available to the Administrator, which may include, 

but is not limited to, monitoring results, review of operation 

and maintenance procedures, review of operation and maintenance 

records, and inspection of the source. 

 39. Section 63.827 is amended by adding introductory text 

to read as follows: 

§63.827 Performance test methods.

 Performance tests shall be conducted under such conditions 

as the Administrator specifies to the owner or operator based on 

representative performance of the affected source for the period 

being tested. Upon request, the owner or operator shall make 

available to the Administrator such records as may be necessary 

to determine the conditions of performance tests. 

* * * * * 

40. Section 63.829 is amended by adding paragraphs (g) and 

(h) to read as follows: 

§63.829 Recordkeeping requirements.

* * * * * 

 (g) Each owner or operator of an affected source subject 

to this subpart shall maintain records of the occurrence and 

duration of each malfunction of operation (i.e., process 
Page 354 of 387 

equipment), air pollution control equipment, or monitoring 

equipment. 

 (h) Each owner or operator of an affected source subject 

to this subpart shall maintain records of actions taken during 

periods of malfunction to minimize emissions in accordance with 

§63.823(b), including corrective actions to restore 

malfunctioning process and air pollution control and monitoring 

equipment to its normal or usual manner of operation. 

41. Section 63.830 is amended by: 

(a) Removing and reserving paragraph (b)(5); and 

(b) Adding paragraph (b)(6)(v) to read as follows: 

§63.830 Reporting requirements. 

* * * * * 

 (b) * * * 

 (5) [Reserved] 

 (6) * * * 

 (v) The number, duration, and a brief description for each 

type of malfunction which occurred during the reporting period 

and which caused or may have caused any applicable emission 

limitation to be exceeded. The report must also include a 

description of actions taken by an owner or operator during a 

malfunction of an affected source to minimize emissions in 

accordance with §63.823(b), including actions taken to correct a 

malfunction. 
Page 355 of 387 

42. Table 1 to Subpart KK of part 63 is amended by: 

 (a) Removing row 63.6(e); 

 (b) Adding rows 63.6(e)(1)(i), 63.6(e)(1)(ii); 

63.6(e)(1)(iii), 63.6(e)(2), and 63.6(e)(3); 

 (c) Removing row 63.6(f); 

 (d) Adding rows 63.6(f)(1) and 63.6(f)(2)-(f)(3); 

 (e) Removing row 63.7; 

 (f) Adding rows 63.7(a)-(d), 63.7(e)(1), and 63.7(e)(2)-

(e)(4); 

 (g) Removing row 63.8(d)-(f); 

 (h) Adding rows 63.8(d)(1)-(2), 63.8(d)(3), and 63.8(e)-

(f); 

 (i) Removing rows 63.10(b)(1)-(b)(3), 63.10(c)(10)-

(c)(15), and 63.10(d)(4)-(d)(5); 

 (b) Adding rows 63.10(b)(1), 63.10(b)(2)(i), 

63.10(b)(2)(ii), 63.10(b)(2)(iii), 63.10(b)(2)(iv)-(b)(2)(v), 

63.10(b)(2)(vi)-(b)(2)(xiv), 63.10(b)(3), 63.10(c)(10), 

63.10(c)(11), 63.10(c)(12)-(c)(14), 63.10(c)(15), 63.10(d)(4), 

and 63.10(d)(5) to read as follows: 

TABLE 1 TO SUBPART KK OF PART 63 – APPLICABILITY OF GENERAL 

PROVISIONS TO SUBPART KK 

General provisons 

reference Applicable to 

subpart KK Comment 

* * * * * * * 
Page 356 of 387 

§63.6(e)(1)(i) No. See 63.823(b) for 

general duty 

requirement. Any 

cross-reference to 

63.6(e)(1)(i) in any 

other general 

provision incorporated 

by reference shall be 

treated as a crossreference to 

63.823(b). 

§63.6(e)(1)(ii) No. 

§63.6(e)(1)(iii) Yes. 

§63.6(e)(2) No. Section reserved. 

§63.6(e)(3) No. 

§63.6(f)(1) No. 

§63.6(f)(2)-(f)(3) Yes. 

* * * * * * * 

§63.7(a)-(d) Yes. 

§63.7(e)(1) No. See 63.827 

introductory text. 

Any cross-reference to 

63.7(e)(1) in any 

other general 

provision incorporated 

by reference shall be 

treated as a crossreference to 63.827 

introductory text. 

§63.7(e)(2)-(e)(4) Yes. 

* * * * 

* * * 

§63.8(d)(1)-(2) Yes. 

§63.8(d)(3) Yes, except 

for last 

sentence. 

§63.8(e)-(f) Yes. 

* * * * 

* * * 

§63.10(b)(1) Yes. 

§63.10(b)(2)(i) No. 

§63.10(b)(2)(ii) No. See 63.829(g) for 

recordkeeping of 

occurrence and 

duration of 

malfunctions. See 
Page 357 of 387 

63.829(h) for 

recordkeeping of 

actions taken during 

malfunction. Any 

cross-reference to 

63.10(b)(2)(ii) in any 

other general 

provision incorporated 

by reference shall be 

treated as a crossreference to 

63.829(g). 

§63.10(b)(2)(iii) Yes. 

§63.10(b)(2)(iv)-

(b)(2)(v) 

No. 

§63.10(b)(2)(vi)-

(b)(2)(xiv) 

Yes. 

§63.10(b)(3) Yes. 

* * * * 

* * * 

§63.10(c)(10) No. See 63.830(b)(6)(v) 

for reporting 

malfunctions. Any 

cross-reference to 

63.10(c)(10) in any 

other general 

provision incorporated 

by reference shall be 

treated as a crossreference to 

63.830(b)(6)(v). 

§63.10(c)(11) No. See 63.830(b)(6)(v) 

for reporting 

malfunctions. Any 

cross-reference to 

63.10(c)(11) in any 

other general 

provision incorporated 

by reference shall be 

treated as a crossreference to 

63.830(b)(6)(v). 

§63.10(c)(12)-

(c)(14) 

Yes. 

§63.10(c)(15) No. 

* * * * 

* * * 
Page 358 of 387 

§63.10(d)(4) Yes. 

§63.10(d)(5) No. 

* * * * 

* * * 

Subpart CCC-–[AMENDED] 

43. Section 63.1155 is amended by adding paragraph (d) to 

read as follows: 

§63.1155 Applicability. 

* * * * * 

(d) In response to an action to enforce the standards set 

forth in this subpart, you may assert a civil defense to a claim 

for civil penalties for exceedances of such standards that are 

caused by a malfunction, as defined in §63.2. Appropriate 

penalties may be assessed, however, if the respondent fails to 

meet it’s burden of proving all the requirements in the 

affirmative defense. The affirmative defense shall not be 

available for claims for injunctive relief. 

(1) To establish the affirmative defense in any action to 

enforce such a limit, the owners or operators of facilities must 

timely meet the notification requirements of paragraph (d)(2) of 

this section, and must prove by a preponderance of evidence 

that: 

(i) The excess emissions were caused by a sudden, short, 

infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, or a process to operate in a normal an 
Page 359 of 387 

usual manner; and could not have been prevented through careful 

planning, proper design, or better operation and maintenance 

practices; and did not stem from any activity or event that 

could have been foreseen and avoided, or planned for; and were 

not part of a recurring pattern indicative of inadequate design, 

operation, or maintenance; and 

(ii) Repairs were made as expeditiously as possible when 

the applicable emission limitations were being exceeded. Offshift and overtime labor were used, to the extent practicable to 

make these repairs; and 

(iii) The frequency, amount, and duration of the excess 

emissions (including any bypass) were minimized to the maximum 

extent practicable during periods of such emissions; and 

(iv) If the excess emissions resulted from a bypass of 

control equipment or a process, then the bypass was unavoidable 

to prevent loss of life, severe personal injury, or severe 

property damage; and 

(v) All possible steps were taken to minimize the impact 

of the excess emissions on ambient air quality, the environment, 

and human health; and 

(vi) All emissions monitoring and control systems were 

kept in operation if at all possible; and 
Page 360 of 387 

(vii) Your actions in response to the excess emissions 

were documented by properly signed, contemporaneous operating 

logs; and 

(viii) At all times, the facility was operated in a manner 

consistent with good practices for minimizing emissions; and 

(ix) The owner or operator has prepared a written root 

cause analysis to determine, correct, and eliminate the primary 

causes of the malfunction and the excess emissions resulting 

from the malfunction event at issue. The analysis shall also 

specify, using the best monitoring methods and engineering 

judgment, the amount of excess emissions that were the result of 

the malfunction. 

(2) Notification. The owner or operator of the facility 

experiencing an exceedance of its emission limit(s) during a 

malfunction shall notify the Administrator by telephone or 

facsimile (FAX) transmission as soon as possible, but no later 2 

business days after the initial occurrence of the malfunction, 

if it wishes to avail itself of an affirmative defense to civil 

penalties for that malfunction. The owner or operator seeking 

to assert an affirmative defense shall also submit a written 

report to the Administrator within 30 days of the initial 

occurrence of the exceedance of the standard in this subpart to 

demonstrate, with all necessary supporting documentation, that 
Page 361 of 387 

it has met the requirements set forth in paragraph (d)(1) of 

this section. 

45. Section 63.1156 is amended by adding in alphabetical 

order a definition for “affirmative defense” to read as follows: 

§63.1156 Definitions. 

* * * * * 

Affirmative defense means, in the context of an enforcement 

proceeding, a response or a defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the 

merits of which are independently and objectively evaluated in a 

judicial or administrative proceeding. 

* * * * * 

46. Section 63.1159 is amended by adding paragraph (c) to 

read as follows: 

§63.1159 Operational and equipment standards for existing, 

new, or reconstructed sources. 

* * * * * 

 (c) At all times, each owner or operator must operate and 

maintain any affected source subject to the requirements of this 

subpart, including associated air pollution control equipment 

and monitoring equipment, in a manner consistent with safety and 

good air pollution control practices for minimizing emissions. 

The general duty to minimize emissions does not require the 
Page 362 of 387 

owner or operator to make any further efforts to reduce 

emissions if levels required by this standard have been 

achieved. Determination of whether such operation and 

maintenance procedures are being used will be based on 

information available to the Administrator which may include, 

but is not limited to, monitoring results, review of operation 

and maintenance procedures, review of operation and maintenance 

records, and inspection of the source. 

47. Section 63.1160 is amended by: 

(a) Removing paragraph (b)(1); 

(b) Revising and redesignating paragraph (b)(2) as 

paragraph (b)(1); and 

(c) Redesignating paragraph (b)(3) as paragraph (b)(2) to 

read as follows: 

§63.1160 Compliance dates and maintenance requirements. 

* * * * * 

(b) Maintenance requirements. (1) The owner or operator 

shall prepare an operation and maintenance plan for each 

emission control device to be implemented no later than the 

compliance date. The plan shall be incorporated by reference 

into the source's title V permit. All such plans must be 

consistent with good maintenance practices, and, for a scrubber 

emission control device, must at a minimum: 

(i) Require monitoring and recording the pressure drop 
Page 363 of 387 

across the scrubber once per shift while the scrubber is 

operating in order to identify changes that may indicate a need 

for maintenance; 

(ii) Require the manufacturer's recommended maintenance at 

the recommended intervals on fresh solvent pumps, recirculating 

pumps, discharge pumps, and other liquid pumps, in addition to 

exhaust system and scrubber fans and motors associated with 

those pumps and fans; 

(iii) Require cleaning of the scrubber internals and mist 

eliminators at intervals sufficient to prevent buildup of solids 

or other fouling; 

(iv) Require an inspection of each scrubber at intervals 

of no less than 3 months with: 

(A) Cleaning or replacement of any plugged spray nozzles 

or other liquid delivery devices; 

(B) Repair or replacement of missing, misaligned, or 

damaged baffles, trays, or other internal components; 

(C) Repair or replacement of droplet eliminator elements 

as needed; 

(D) Repair or replacement of heat exchanger elements used 

to control the temperature of fluids entering or leaving the 

scrubber; and 

(E) Adjustment of damper settings for consistency with the 

required air flow. 
Page 364 of 387 

(v) If the scrubber is not equipped with a viewport or 

access hatch allowing visual inspection, alternate means of 

inspection approved by the Administrator may be used. 

(vi) The owner or operator shall initiate procedures for 

corrective action within 1 working day of detection of an 

operating problem and complete all corrective actions as soon as 

practicable. Procedures to be initiated are the applicable 

actions that are specified in the maintenance plan. Failure to 

initiate or provide appropriate repair, replacement, or other 

corrective action is a violation of the maintenance requirement 

of this subpart. 

(vii) The owner or operator shall maintain a record of 

each inspection, including each item identified in paragraph 

(b)(2)(iv) of this section, that is signed by the responsible 

maintenance official and that shows the date of each inspection, 

the problem identified, a description of the repair, 

replacement, or other corrective action taken, and the date of 

the repair, replacement, or other corrective action taken. 

(2) The owner or operator of each hydrochloric acid 

regeneration plant shall develop and implement a written 

maintenance program. The program shall require: 

(i) Performance of the manufacturer's recommended 

maintenance at the recommended intervals on all required systems 

and components; 
Page 365 of 387 

(ii) Initiation of procedures for appropriate and timely 

repair, replacement, or other corrective action within 1 working 

day of detection; and 

(iii) Maintenance of a daily record, signed by a 

responsible maintenance official, showing the date of each 

inspection for each requirement, the problems found, a 

description of the repair, replacement, or other action taken, 

and the date of repair or replacement. 

48. Section 63.1161 is amended by revising paragraph (a) 

introductory text to read as follows: 

§63.1161 Performance testing and test methods. 

(a) Demonstration of compliance. The owner or operator 

shall conduct an initial performance test for each process or 

emission control device to determine and demonstrate compliance 

with the applicable emission limitation according to the 

requirements in §63.7 of subpart A of this part and in this 

section. Performance tests shall be conducted under such 

conditions as the Administrator specifies to the owner or 

operator based on representative performance of the affected 

source for the period being tested. Upon request, the owner or 

operator shall make available to the Administrator such records 

as may be necessary to determine the conditions of performance 

tests. 

* * * * *
Page 366 of 387 

49. Section 63.1164 is amended by: 

a. Revising paragraph (c) introductory text; and 

 b. Removing paragraphs (c)(1), (c)(2), and (c)(3) to read 

as follows: 

§63.1164 Reporting Requirements.

* * * * * 

(c) The number, duration, and a brief description for each 

type of malfunction which occurred during the reporting period 

and which caused or may have caused any applicable emission 

limitation to be exceeded shall be stated in a semiannual 

report. The report must also include a description of actions 

taken by an owner or operator during a malfunction of an 

affected source to minimize emissions in accordance with 

§63.1159(c), including actions taken to correct a malfunction. 

The report, to be certified by the owner or operator or other 

responsible official, shall be submitted semiannually and 

delivered or postmarked by the 30th day following the end of 

each calendar half. 

50. Section 63.1165 is amended by: 

 a. Revising paragraph (a)(1); 

 b. Revising paragraph (a)(4); 

 c. Removing paragraph (a)(5) and redesignating existing 

paragraphs (a)(6) through (a)(11) as (a)(5) through (a)(10) to 

read as follows: 
Page 367 of 387 

§63.1165 Recordkeeping requirements. 

(a) * * * 

(1) The occurrence and duration of each malfunction of 

operation (i.e., process equipment); 

* * * * * 

(4) Actions taken during periods of malfunction to 

minimize emissions in accordance with §63.1259(c) and the dates 

of such actions (including corrective actions to restore 

malfunctioning process and air pollution control equipment to 

its normal or usual manner of operation); 

(5) All required measurements needed to demonstrate 

compliance with the standard and to support data that the source 

is required to report, including, but not limited to, 

performance test measurements (including initial and any 

subsequent performance tests) and measurements as may be 

necessary to determine the conditions of the initial test or 

subsequent tests; 

(6) All results of initial or subsequent performance 

tests; 

(7) If the owner or operator has been granted a waiver 

from recordkeeping or reporting requirements under §63.10(f) of 

subpart A of this part, any information demonstrating whether a 

source is meeting the requirements for a waiver of recordkeeping 

or reporting requirements; 
Page 368 of 387 

(8) If the owner or operator has been granted a waiver 

from the initial performance test under §63.7(h) of subpart A of 

this part, a copy of the full request and the Administrator's 

approval or disapproval; 

(9) All documentation supporting initial notifications and 

notifications of compliance status required by §63.9 of subpart 

A of this part; and 

(10) Records of any applicability determination, including 

supporting analyses. 

* * * * * 

51. Table 1 to Subpart CCC is amended by: 

a. Revising entry 63.6(a)-(g); 

b. Adding entries 63.6(e)(1)(i), 63.6(e)(1)(ii), 

63.6(e)(1)(iii), 63.6(e)(2), 63.6(e)(3), 63.6(f)(1), 63.6(f)(2)-

(3), 63.6(g); 

c. Removing entry 63.7-63.9; 

d. Adding entries 63.7, 63.8(a)-(c), 63.8(d)(1)-(2), 

63.8(d)(3), and 63.8(e)-(f); 

e. Removing entry 63.10(a)-(c); 

f. Adding entries 63.10(a), 63.10(b)(1), 63.10(b)(2)(i), 

63.10(b)(2)(ii), 63.10(b)(2)(iii), 63.10(b)(2)(iv)-(v), 

63.10(b)(2)(vi)-(xvi), 63.10(b)(3), 63.10(c)(1)-(9), 

63.10(c)(10), 63.10(c)(11), 63.10(c)(12)-(14), and 63.10(c)(15); 

g. Removing entry 63.10(d)(4)-(5); 
Page 369 of 387 

h. Adding entries 63.10(d)(4) and 63.10(d)(5) to read as 

follows: 

TABLE 1 TO SUBPART CCC OF PART 63—APPLICABILITY OF GENERAL 

PROVISIONS (40 CFR PART 63, SUBPART A) TO SUBPART CCC 

Reference 

Applies to 

Subpart CCC Explanation 

* * * * * * * 

63.6 (a)–(d)............ Yes. 

63.6(e)(1)(i)......... No.................................... See §63.1259(c) for general duty 

requirement. Any cross-reference 

to §63.6(e)(1)(i) in any other 

general provision incorporated 

by reference shall be treated as 

a cross-reference to 

§63.1259(c). 

63.6(e)(1)(ii)...... No. 

63.6(e)(1)(iii)... Yes. 

63.6(e)(2).................. No.................................... Section reserved. 

63.6(e)(3).................. No. 

63.6(f)(1).................. No 

63.6(f)(2)-(3)...... Yes. 

63.6(g)........................... Yes. 

* * * * * * * 

63.7.................................... Yes. 

63.8(a)-(c)............... Yes. 

63.8(d)(1)-(2)...... Yes. 

63.8(d)(3).................. Yes, except for 

last sentence. 

63.8(e)-(f)............... Yes. 

* * * * * * * 

63.10(a)........................ Yes. 

63.10(b)(1)............... Yes. 

63.10(b)(2)(i)...... No. 

63.10(b)(2)(ii)... No. See §63.1265(a)(1) for 
Page 370 of 387 

recordkeeping of occurrence and 

duration of malfunctions. See 

§63.1265(a)(4) for recordkeeping 

of actions taken during 

malfunction. Any cross-reference 

to §63.10(b)(2)(ii) in any other 

general provision incorporated 

by reference shall be treated as 

a cross-reference to 

§63.1265(a)(1). 

63.10(b)(2)(iii) Yes. 

63.10(b)(2)(iv)-

(b)(2)(v)..................... No. 

63.10(b)(2)(vi)-

(b)(2)(xiv)............... Yes. 

63.10(b)(3)............... Yes. 

* * * * * * * 

63.10(c)(1)-(9)... Yes. 

63.10(c)(10)............ No. See §63.1164(c) for reporting 

malfunctions. Any crossreference to §63.10(c)(10) in 

any other general provision 

incorporated by reference shall 

be treated as a cross-reference 

to §63.1164(c). 

63.10(c)(11)............ No. See §63.1164(c) for reporting 

malfunctions. Any crossreference to §63.10(c)(11) in 

any other general provision 

incorporated by reference shall 

be treated as a cross-reference 

to §63.1164(c). 

63.10(c)(12)-

(c)(14)........................... Yes. 

63.10(c)(15)............ No. 

63.10(d)(4)............... Yes. 

63.10(d)(5)............... No. 

* * * * * * * 
Page 371 of 387 

Subpart GGG-–[AMENDED] 

52. Section 63.1250 is amended as follows: 

a. By revising paragraph (g)(1); 

b. By revising paragraph (g)(2); 

c. By revising paragraph (g)(3); and 

d. By revising paragraph (g)(4). 

The revisions read as follows: 

§63.1250 Applicability. 

* * * * * 

(g) Applicability of this subpart. (1) Each provision set 

forth in this subpart shall apply at all times, except that the 

provisions set forth in §63.1255 of this subpart shall not apply 

during periods of nonoperation of the PMPU (or specific portion 

thereof) in which the lines are drained and depressurized 

resulting in the cessation of the emissions to which §63.1255 of 

this subpart applies. 

(2) The owner or operator shall not shut down items of 

equipment that are required or utilized for compliance with the 

emissions limitations of this subpart during times when 

emissions (or, where applicable, wastewater streams or 

residuals) are being routed to such items of equipment, if the 

shutdown would contravene emissions limitations of this subpart 

applicable to such items of equipment. This paragraph does not 
Page 372 of 387 

apply if the owner or operator must shut down the equipment to 

avoid damage to a PMPU or portion thereof. 

(3) At all times, each owner or operator must operate and 

maintain any affected source subject to the requirements of this 

subpart, including associated air pollution control equipment 

and monitoring equipment, in a manner consistent with safety and 

good air pollution control practices for minimizing emissions. 

The general duty to minimize emissions does not require the 

owner or operator to make any further efforts to reduce 

emissions if levels required by this standard have been 

achieved. Determination of whether such operation and 

maintenance procedures are being used will be based on 

information available to the Administrator which may include, 

but is not limited to, monitoring results, review of operation 

and maintenance procedures, review of operation and maintenance 

records, and inspection of the source. 

(4) In response to an action to enforce the standards set 

forth in this subpart, you may assert a civil defense to a claim 

for civil penalties for exceedances of such standards that are 

caused by a malfunction, as defined in §63.2. Appropriate 

penalties may be assessed, however, if the respondent fails to 

meet it’s burden of proving all the requirements in the 

affirmative defense. The affirmative defense shall not be 

available for claims for injunctive relief. 
Page 373 of 387 

(i) To establish the affirmative defense in any action to 

enforce such a limit, the owners or operators of facilities must 

timely meet the notification requirements of paragraph (4)(ii) 

of this subsection, and must prove by a preponderance of 

evidence that: 

(A) The excess emissions were caused by a sudden, short, 

infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, or a process to operate in a normal and 

usual manner; and could not have been prevented through careful 

planning, proper design, or better operation and maintenance 

practices; and did not stem from any activity or event that 

could have been foreseen and avoided, or planned for; and were 

not part of a recurring pattern indicative of inadequate design, 

operation, or maintenance; and 

(B) Repairs were made as expeditiously as possible when 

the applicable emission limitations were being exceeded. Offshift and overtime labor were used, to the extent practicable to 

make these repairs; and 

(C) The frequency, amount, and duration of the excess 

emissions (including any bypass) were minimized to the maximum 

extent practicable during periods of such emissions; and 

(D) If the excess emissions resulted from a bypass of 

control equipment or a process, then the bypass was unavoidable 
Page 374 of 387 

to prevent loss of life, severe personal injury, or severe 

property damage; and 

(E) All possible steps were taken to minimize the impact 

of the excess emissions on ambient air quality, the environment, 

and human health; and 

(F) All emissions monitoring and control systems were kept 

in operation if at all possible; and 

(G) Your actions in response to the excess emissions were 

documented by properly signed, contemporaneous operating logs; 

and 

(H) At all times, the facility was operated in a manner 

consistent with good practices for minimizing emissions; and 

(I) The owner or operator has prepared a written root 

cause analysis to determine, correct, and eliminate the primary 

causes of the malfunction and the excess emissions resulting 

from the malfunction event at issue. The analysis shall also 

specify, using the best monitoring methods and engineering 

judgment, the amount of excess emissions that were the result of 

the malfunction. 

(ii) Notification. The owner or operator of the facility 

experiencing an exceedance of its emission limit(s) during a 

malfunction shall notify the Administrator by telephone or 

facsimile (FAX) transmission as soon as possible, but no later 2 

business days after the initial occurrence of the malfunction, 
Page 375 of 387 

if it wishes to avail itself of an affirmative defense to civil 

penalties for that malfunction. The owner or operator seeking 

to assert an affirmative defense shall also submit a written 

report to the Administrator within 30 days of the initial 

occurrence of the exceedance of the standard in this subpart to 

demonstrate, with all necessary supporting documentation, that 

it has met the requirements set forth in paragraph (4)(i) of 

this subsection. 

* * * * * 

53. Section 63.1251 is amended by adding in alphabetical 

order a definition for “affirmative defense” to read as follow: 

§63.1251 Definitions. 

* * * * * 

Affirmative defense means, in the context of an enforcement 

proceeding, a response or a defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the 

merits of which are independently and objectively evaluated in a 

judicial or administrative proceeding. 

* * * * * 

54. Section 63.1255 is amended by revising paragraph 

(g)(4)(v)(A) to read as follow: 

§63.1255 Standards: Equipment leaks. 

* * * * * 

 (g) * * * 
Page 376 of 387 

 (4) * * * 

 (v) * * * 

 (A) The owner or operator may develop a written procedure 

that identifies the conditions that justify a delay of repair. 

The written procedures shall be included in a document that is 

maintained at the plant site. Reasons for delay of repair may 

be documented by citing the relevant sections of the written 

procedure. 

* * * * * 

55. Section 63.1256 is amended by revising paragraph 

(a)(4)(i), and removing paragraphs (a)(4)(iii) and (iv) to read 

as follows: 

§63.1256 Standards: Wastewater. 

* * * * * 

 (a) * * * 

 (4) * * * 

 (i) The owner or operator shall prepare a description of 

maintenance procedures for management of wastewater generated 

from the emptying and purging of equipment in the process during 

temporary shutdowns for inspections, maintenance, and repair 

(i.e., a maintenance turnaround) and during periods which are 

not shutdowns (i.e., routine maintenance). The descriptions 

shall be included in a document that is maintained at the plant 

site and shall: 
Page 377 of 387 

* * * * * 

56. Section 63.1257 is amended by revising paragraphs (a) 

introductory text and (e)(6)(ii) to read as follows: 

§63.1257 Test methods and compliance procedures. 

(a) General. Except as specified in paragraph (a)(5) of 

this section, the procedures specified in paragraphs (c), (d), 

(e), and (f) of this section are required to demonstrate initial 

compliance with §§63.1253, 63.1254, 63.1256, and 63.1252(e), 

respectively. The provisions in paragraphs (a)(2) through (3) 

apply to performance tests that are specified in paragraphs (c), 

(d), and (e) of this section. The provisions in paragraph 

(a)(5) of this section are used to demonstrate initial 

compliance with the alternative standards specified in 

§§63.1253(d) and 63.1254(c). The provisions in paragraph (a)(6) 

of this section are used to comply with the outlet concentration 

requirements specified in §§63.1253(c), 63.1254(a)(2)(i), and 

(a)(3)(ii)(B), 63.1254(b)(i), and 63.1256(h)(2). Performance 

tests shall be conducted under such conditions as the 

Administrator specifies to the owner or operator based on 

representative performance of the affected source for the period 

being tested. Upon request, the owner or operator shall make 

available to the Administrator such records as may be necessary 

to determine the conditions of performance tests. 

* * * * * 
Page 378 of 387 

 (e) * * * 

 (6) * * * 

 (ii) The owner or operator may consider the inlet to the 

equalization tank as the inlet to the biological treatment 

process if the wastewater is conveyed by hard-piping from either 

the last previous treatment process or the point of 

determination to the equalization tank; and the wastewater is 

conveyed from the equalization tank exclusively by hard-piping 

to the biological treatment process and no treatment processes 

or other waste management units are used to store, handle, or 

convey the wastewater between the equalization tank and the 

biological treatment process; and the equalization tank is 

equipped with a fixed roof and a closed-vent system that routes 

emissions to a control device that meets the requirements of 

§63.1256(b)(1)(i) through (iv) and §63.1256(b)(2)(i). * * * 

* * * * * 

57. Section 63.1258 is amended by removing paragraph 

(b)(8)(iv). 

 58. Section 63.1259 is amended by revising paragraph 

(a)(3) and removing paragraphs (a)(3)(i)-(iii) to read as 

follows: 

§63.1259 Recordkeeping requirements. 

* * * * * 

 (a) * * * 
Page 379 of 387 

 (3) Malfunction Records. Each owner or operator of an 

affected source subject to this subpart shall maintain records 

of the occurrence and duration of each malfunction of operation 

(i.e., process equipment), air pollution control equipment, or 

monitoring equipment. Each owner or operator shall maintain 

records of actions taken during periods of malfunction to 

minimize emissions in accordance with §63.1250(g)(3), including 

corrective actions to restore malfunctioning process and air 

pollution control and monitoring equipment to its normal or 

usual manner of operation. 

* * * * * 

 59. Section 63.1260 is amended by revising paragraph (i) 

and removing paragraphs (i)(1) and (i)(2) to read as follows: 

§63.1260 Reporting requirements. 

* * * * * 

 (i) The number, duration, and a brief description for each 

type of malfunction which occurred during the reporting period 

and which caused or may have caused any applicable emission 

limitation to be exceeded. The report must also include a 

description of actions taken by an owner or operator during a 

malfunction of an affected source to minimize emissions in 

accordance with §63.1250(g)(3), including actions taken to 

correct a malfunction. 

* * * * * 
Page 380 of 387 

60. Table 1 to Subpart GGG is amended by: 

 a. Removing row 63.6(e); 

 b. Adding rows 63.6(e)(1)(i), 63.6(e)(1)(ii), 

63.6(e)(1)(iii), 63.6(e)(2), and 63.6(e)(3); 

 c. Removing row 63.6(f)-(g); 

d. Adding rows 63.6(f)(1), 63.6(f)(2)-(3), 63.6(g); 

e. Removing row 63.7(e); 

f. Adding rows 63.7(e)(1) and 63.7(e)(2)-(4); 

g. Revising row 63.8(d); 

h. Adding rows 63.8(d)(1)-(2) and 63.8(d)(3). 

63.10(b)(2)(ii); 

i. Removing row 63.10(c)-(d)(2); 

 j. Adding rows 63.10(c)(1)-(9), 63.10(c)(10), 

63.10(c)(11), 63.10(c)(12)-(14), and 63.10(d)(1)-(2); 

k. Removing row 63.10(d)(4-5); and 

 l. Adding rows 63.10(d)(4) and 63.10(d)(5) to read as 

follows:

Table 1 to Subpart GGG of Part 63—General Provisions 

Applicability to Subpart GGG 

General 

provisions 

reference 

Summary of 

requirements 

Applies 

to 

subpart 

GGG Comments 

* * * * * * * 

§63.6(e)(1)(i) Requirements 

during periods 

of startup, 

shutdown, and 

No See 63.1250(g)(3) for 

general duty 

requirement. Any 

cross-reference to 
Page 381 of 387 

malfunction 63.6(e)(1)(i) in any 

other general 

provision 

incorporated by 

reference shall be 

treated as a crossreference to 

63.1250(g)(3). 

§63.6(e)(1)(ii) Malfunction 

correction 

requirements 

No 

§63.6(e)(1)(iii) Enforceability 

of operation and 

maintenance 

requirements 

Yes 

§63.6(e)(2) Reserved No Section reserved 

§63.6(e)(3) Startup, 

shutdown, and 

malfunction plan 

requirements 

No 

* * * * * * * 

63.6(f)(1) 

Applicability of 

nonopacity 

emission 

standards 

No 

63.6(f)(2)-(3) 

Methods of 

determining 

compliance and 

findings 

compliance 

Yes 

63.6(g) 

Use of an 

alternative 

nonopacity 

emission 

standard 

Yes 

* * * * * * * 

63.7(e)(1) 

Conduct of 

performance 

tests 

No 

See 63.1257(a) text. 

Any cross-reference 

to 63.7(e)(1) in any 

other general 

provision 
Page 382 of 387 

incorporated by 

reference shall be 

treated as a crossreference to 

63.1257(a). 

63.7 (e)(2)-(4) 

Performance 

tests 

requirements 

Yes 

* * * * * * * 

63.8(d)(1)-(2) 

CMS quality 

control program 

requirements 

Yes 

63.8(d)(3) 

CMS quality 

control program 

recordkeeping 

requirements 

Yes, 

except 

for last 

sentence.

* * * * * * * 

63.10(c)(1)-(9) 

Additional 

recordkeeping 

requirements for 

sources with 

continuous 

monitoring 

systems 

Yes 

63.10(c)(10) 

Malfunction 

recordkeeping 

requirement 

No 

Subpart GGG specifies 

recordkeeping 

requirements. 

63.10(c)(11) Malfunction 

corrective 

action 

recordkeeping 

requirement 

No Subpart GGG specifies 

recordkeeping 

requirements. 

63.10(c)(12)- 

(14) 

Additional 

recordkeeping 

requirements for 

sources with 

continuous 

monitoring 

systems 

Yes 

63.10(c)(15) Additional SSM 

recordkeeping 

No 
Page 383 of 387 

requirements 

* * * * * * * 

63.10(d)(1)-(2) General 

reporting 

requirements 

Yes 

* * * * * * * 

63.10(d)(4) Progress report 

requirements 

Yes 

63.10(d)(5) Startup, 

shutdown, and 

malfunction 

report 

requirements 

No Subpart GGG specifies 

reporting 

requirements. 

* * * * * * * 

Appendix A-–[AMENDED] 

61. Appendix A to part 63, Method 306-B is amended by: 

a. Revising paragraph 1.2; 

b. Revising paragraph 6.1; 

c. Revising paragraph 11.1; 

d. Adding paragraphs 11.1.1 through 11.1.4.10; and 

e. Revising paragraph 11.2 to read as follows: 

METHOD 306B--SURFACE TENSION MEASUREMENT FOR TANKS USED AT 

DECORATIVE CHROMIUM ELECTROPLATING AND CHROMIUM ANODIZING 

FACILITIES 

* * * * * 

1.0 Scope and Application

* * * * * 
Page 384 of 387 

 1.2 Applicability. This method is applicable to all 

chromium electroplating and chromium anodizing operations, and 

continuous chromium plating at iron and steel facilities where a 

wetting agent is used in the tank as the primary mechanism for 

reducing emissions from the surface of the plating solution. 

* * * * * 

6.0 Equipment and Supplies

 6.1 Stalagmometer. Any commercially available 

stalagmometer or equivalent surface tension measuring device may 

be used to measure the surface tension of the plating or 

anodizing tank liquid provided the procedures specified in 

Section 11.1.2 are followed. 

* * * * * 

11.0 Analytical Procedure

 11.1 Procedure. The surface tension of the tank bath may 

be measured using a tensiometer, stalagmometer, or any other 

equivalent surface tension measuring device for measuring 

surface tension in dynes per centimeter. 

 11.1.1 If a tensiometer is used, the procedures specified 

in ASTM Method D 1331-89 must be followed. 

 11.1.2 If a stalagmometer is used, the procedures 

specified in Sections 11.1.2.1 through 11.1.2.3 must be 

followed. 
Page 385 of 387 

11.1.2.1 Check the stalagmometer for visual signs of 

damage. If the stalagmometer appears to be chipped, cracked, or 

otherwise in disrepair, the instrument shall not be used. 

11.1.2.2 Using distilled or deionized water and following 

the procedures provided by the manufacturer, count the number of 

drops corresponding to the distilled/deionized water liquid 

volume between the upper and lower etched marks on the 

stalagmometer. If the number of drops for the 

distilled/deionized water is not within ±1 drop of the number 

indicated on the instrument, the stalagmometer must be cleaned, 

using the procedures specified in Sections 11.1.4.1 through 

11.1.4.10 of this method, before using the instrument to measure 

the surface tension of the tank liquid. 

11.1.2.2.1 If the stalagmometer must be cleaned, as 

indicated in Section 11.1.2.2, repeat the procedure specified in 

Section 11.1.2.2 before proceeding. 

11.1.2.2.2 If, after cleaning and performing the 

procedure in Section 11.1.2.2, the number of drops indicated for 

the distilled/deionized water is not within ±1 drop of the 

number indicated on the instrument, either use the number of 

drops corresponding to the distilled/deionized water volume as 

the reference number of drops, or replace the instrument. 
Page 386 of 387 

 11.1.3 Determine the surface tension of the tank liquid 

using the procedures specified by the manufacturer of the 

stalagmometer. 

11.1.4 Stalagmometer cleaning procedures. The procedures 

specified in Sections 11.1.4.1 through 11.1.4.10 shall be used 

for cleaning a stalagmometer, as required by Section 11.1.2.2. 

11.1.4.1 Set up the stalagmometer on its stand in a fume 

hood. 

11.1.4.2 Place a clean 150 (mL) beaker underneath the 

stalagmometer and fill the beaker with reagent grade 

concentrated nitric acid. 

11.1.4.3 Immerse the bottom tip of the stalagmometer 

(approximately 1 centimeter (0.5 inches)) into the beaker. 

11.1.4.4 Squeeze the rubber bulb and pinch at the arrow up 

(1) position to collapse. 

11.1.4.5 Place the bulb end securely on top end of 

stalagmometer and carefully draw the nitric acid by pinching the 

arrow up (1) position until the level is above the top etched 

line. 

11.1.4.6 Allow the nitric acid to remain in stalagmometer 

for 5 minutes, then carefully remove the bulb, allowing the acid 

to completely drain. 

11.1.4.7 Fill a clean 150 mL beaker with distilled or 

deionized water. 
Page 387 of 387 

11.1.4.8 Using the rubber bulb per the instructions in 

Sections 11.1.4.4 and 11.1.4.5, rinse and drain stalagmometer 

with deionized or distilled water. 

11.1.4.9 Fill a clean 150 mL beaker with isopropyl 

alcohol. 

11.1.4.10 Again using the rubber bulb per the instructions 

in Sections 11.1.4.4 and 11.1.4.5, rinse and drain stalagmometer 

twice with isopropyl alcohol and allow the stalagmometer to dry 

completely. 

11.2 * * * 

* * * * * 

11.2.2 If a measurement of the surface tension of the 

solution is above the 45 dynes per centimeter limit when 

measured using a stalagmometer, above 35 dynes per centimeter 

when measured using a tensiometer, or above an alternate surface 

tension limit established during the performance test, the time 

interval shall revert back to the original monitoring schedule 

of once every 4 hours. A subsequent decrease in frequency would 

then be allowed according to Section 11.2.1. 

* * * * *