44254 Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 63 

[EPA–HQ–OAR–2016–0442; FRL–9967–61– 

OAR] 

RIN 2060–AS92 

National Emission Standards for 

Hazardous Air Pollutants From the 

Portland Cement Manufacturing 

Industry Residual Risk and 

Technology Review 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing amendments 

to the National Emission Standards for 

Hazardous Air Pollutants (NESHAP) 

From the Portland Cement 

Manufacturing Industry to address the 

results of the residual risk and 

technology review (RTR) the EPA is 

required to conduct in accordance with 

section 112 of the Clean Air Act (CAA). 

We found risks due to emissions of air 

toxics to be acceptable from this source 

category with an ample margin of safety, 

and we identified no new cost-effective 

controls under the technology review to 

achieve further emissions reductions. 

Therefore, we are proposing no 

revisions to the numerical emission 

limits based on these analyses. 

However, the EPA is proposing 

amendments to correct and clarify rule 

requirements and provisions. While the 

proposed amendments would not result 

in reductions in emissions of hazardous 

air pollutants (HAP), this action, if 

finalized, would result in improved 

monitoring, compliance, and 

implementation of the rule. 

DATES:

Comments. Comments must be 

received on or before November 6, 2017. 

Public Hearing. If a public hearing is 

requested by September 26, 2017, the 

EPA will hold a public hearing on 

October 6, 2017. The last day to preregister in advance to speak at the 

public hearing will be October 4, 2017. 

ADDRESSES: Comments. Submit your 

comments, identified by Docket ID No. 

EPA–HQ–OAR–2016–0442, at http://

www.regulations.gov. Follow the online 

instructions for submitting comments. 

Once submitted, comments cannot be 

edited or removed from Regulations.gov. 

The EPA may publish any comment 

received to its public docket. Do not 

submit electronically any information 

you consider to be Confidential 

Business Information (CBI) or other 

information whose disclosure is 

restricted by statute. Multimedia 

submissions (audio, video, etc.) must be 

accompanied by a written comment. 

The written comment is considered the 

official comment and should include 

discussion of all points you wish to 

make. The EPA will generally not 

consider comments or comment 

contents located outside of the primary 

submission (i.e., on the Web, cloud, or 

other file sharing system). For 

additional submission methods, the full 

EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

http://www2.epa.gov/dockets/ 

commenting-epa-dockets. 

Public Hearing. If a hearing is 

requested, it will be held at the EPA 

WJC East Building, 1201 Constitution 

Avenue NW., Washington, DC 20004. If 

a public hearing is requested, then we 

will provide details about the public 

hearing on our Web site at https://

www.epa.gov/stationary-sources-airpollution/portland-cementmanufacturing-industry-nationalemission-standards. The EPA does not 

intend to publish any future notices in 

the Federal Register announcing any 

updates on the request for public 

hearing. Please contact Aimee St. Clair 

at (919) 541–1063 or by email at 

stclair.aimee@epa.gov to request a 

public hearing, to register to speak at the 

public hearing, or to inquire as to 

whether a public hearing will be held. 

FOR FURTHER INFORMATION CONTACT: For 

questions about this proposed action, 

contact Mr. Brian Storey, Sector Policies 

and Programs Division (D243–04), 

Office of Air Quality Planning and 

Standards, U.S. Environmental 

Protection Agency, Research Triangle 

Park, North Carolina 27711; telephone 

number: (919) 541–1103; fax number: 

(919) 541–5450; and email address: 

storey.brian@epa.gov. For specific 

information regarding the risk modeling 

methodology, contact Mr. James Hirtz, 

Health and Environmental Impacts 

Division (C539–02), Office of Air 

Quality Planning and Standards, U.S. 

Environmental Protection Agency, 

Research Triangle Park, North Carolina 

27711; telephone number: (919) 541– 

0881; fax number: (919) 541–0840; and 

email address: hirtz.james@epa.gov. For 

information about the applicability of 

the NESHAP to a particular entity, 

contact Ms. Sara Ayres, Office of 

Enforcement and Compliance 

Assurance, U.S. Environmental 

Protection Agency, U.S. EPA Region 5 

(E–19J), 77 West Jackson Boulevard, 

Chicago, IL 60604; telephone number: 

(312) 353–6266; email address: 

ayres.sara@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Docket. The EPA has established a 

docket for this rulemaking under Docket 

ID No. EPA–HQ–OAR–2016–0442. All 

documents in the docket are listed in 

the Regulations.gov index. Although 

listed in the index, some information is 

not publicly available, e.g., CBI or other 

information whose 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 

Regulations.gov or in hard copy at the 

EPA Docket Center, Room 3334, EPA 

WJC West Building, 1301 Constitution 

Avenue 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. 

Instructions. Direct your comments to 

Docket ID No. EPA–HQ–OAR–2016– 

0442. The EPA’s policy is that all 

comments received will be included in 

the public docket without change and 

may be made available online at http:// 

www.regulations.gov, including any 

personal information provided, unless 

the comment includes information 

claimed to be CBI or other information 

whose disclosure is restricted by statute. 

Do not submit information that you 

consider to be CBI or otherwise 

protected through http://

www.regulations.gov or email. The 

http://www.regulations.gov Web site is 

an ‘‘anonymous access’’ system, which 

means the EPA will not know your 

identity or contact information unless 

you provide it in the body of your 

comment. If you send an email 

comment directly to the EPA without 

going through http://

www.regulations.gov, your email 

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, the 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 the EPA 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, the EPA may not 

be able to consider your comment. 

Electronic files should not include 

special characters or any form of 

encryption and be free of any defects or 


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viruses. For additional information 

about the EPA’s public docket, visit the 

EPA Docket Center homepage at http:// 

www.epa.gov/dockets. 

Preamble Acronyms and 

Abbreviations. We use multiple 

acronyms and terms in this preamble. 

While this list may not be exhaustive, to 

ease the reading of this preamble and for 

reference purposes, the EPA defines the 

following terms and acronyms here: 

ACI activated carbon injection 

AEGL acute exposure guideline levels 

AERMOD air dispersion model used by the 

HEM–3 model 

CAA Clean Air Act 

CalEPA California EPA 

CBI Confidential Business Information 

CDX Central Data Exchange 

CEDRI Compliance and Emissions Data 

Reporting Interface 

CFR Code of Federal Regulations 

CISWI commercial and industrial solid 

waste incinerators 

CO carbon monoxide 

D/F dioxins and furans 

EPA Environmental Protection Agency 

ERP Emergency Response Planning 

ERPG Emergency Response Planning 

Guidelines 

ERT Electronic Reporting Tool 

ESP electrostatic precipitators 

FR Federal Register 

GHGRP Greenhouse Gas Reporting Program 

HAP hazardous air pollutants 

HCl hydrochloric acid 

HEM–3 Human Exposure Model 

HF hydrogen fluoride 

HI hazard index 

HQ hazard quotient 

IRIS Integrated Risk Information System 

km kilometer 

lb/hr pounds per hour 

lb/ton pounds per ton 

LOAEL lowest-observed-adverse-effect level 

MACT maximum achievable control 

technology 

mg/kg-day milligrams per kilogram per day 

mg/m3 milligrams per cubic meter 

mg/Nm3 milligrams per normal cubic meter 

MIR maximum individual risk 

NAAQS National Ambient Air Quality 

Standards 

NAC National Advisory Committee 

NAICS North American Industry 

Classification System 

NAS National Academy of Sciences 

NATA National Air Toxics Assessment 

NEI National Emissions Inventory 

NESHAP national emission standards for 

hazardous air pollutants 

NOX nitrogen oxides 

NOAA National Oceanic and Atmospheric 

Administration 

NOAEL no-observed-adverse-effect level 

NRC National Research Council 

NRDC Natural Resources Defense Council 

NSPS new source performance standards 

NTTAA National Technology Transfer and 

Advancement Act 

OAQPS Office of Air Quality Planning and 

Standards 

OMB Office of Management and Budget 

PB–HAP hazardous air pollutants known to 

be persistent and bio-accumulative in the 

environment 

PCA Portland Cement Association 

PEL probable effect level 

PM particulate matter 

POM polycyclic organic matter 

ppm parts per million 

ppmvd parts per million by volume, dry 

basis 

PRA Paperwork Reduction Act 

REL reference exposure level 

RFA Regulatory Flexibility Act 

RfC reference concentration 

RfD reference dose 

RTO regenerative thermal oxidizers 

RTR residual risk and technology review 

SAB Science Advisory Board 

SCR selective catalytic reduction 

SO2 sulfur dioxide 

TEF toxicity equivalence factors 

TEQ toxic equivalents 

THC total hydrocarbons 

TOSHI target organ-specific hazard index 

tpy tons per year 

TRIM.FaTE Total Risk Integrated 

Methodology.Fate, Transport, and 

Ecological Exposure model 

UF uncertainty factor 

mg/m3 microgram per cubic meter 

UISIS Universal Industrial Sectors 

Integrated Solutions 

UMRA Unfunded Mandates Reform Act 

URE unit risk estimate 

U.S.C. United States Code 

WebFIRE Web Factor Information Retrieval 

System 

Organization of this Document. The 

information in this preamble is 

organized as follows: 

I. 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 the EPA? 

II. Background 

A. What is the statutory authority for this 

action? 

B. What is this source category and how 

does the current NESHAP regulate its 

HAP emissions? 

C. What data collection activities were 

conducted to support this action? 

D. What other relevant background 

information and data are available? 

III. Analytical Procedures 

A. How did we estimate post-MACT risks 

posed by the source category? 

B. How did we consider the risk results in 

making decisions for this proposal? 

C. How did we perform the technology 

review? 

IV. Analytical Results and Proposed 

Decisions 

A. What are the results of the risk 

assessment and analyses? 

B. What are our proposed decisions 

regarding risk acceptability, ample 

margin of safety, and adverse 

environmental effects? 

C. What are the results and proposed 

decisions based on our technology 

review? 

D. What other actions are we proposing? 

E. What compliance dates are we 

proposing? 

V. Summary of Cost, Environmental, and 

Economic Impacts 

A. What are the impacts to affected 

sources? 

B. What are the air quality impacts? 

C. What are the cost impacts? 

D. What are the economic impacts? 

E. What are the benefits? 

VI. Request for Comments 

VII. Submitting Data Corrections 

VIII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

B. Executive Order 13771: Reducing 

Regulations and Controlling Regulatory 

Costs 

C. Paperwork Reduction Act (PRA) 

D. Regulatory Flexibility Act (RFA) 

E. Unfunded Mandates Reform Act 

(UMRA) 

F. Executive Order 13132: Federalism 

G. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

H. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

I. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

J. National Technology Transfer and 

Advancement Act (NTTAA) 

K. Executive Order 12898: Federal Actions 

To Address Environmental Justice in 

Minority Populations and Low-Income 

Populations 

I. General Information 

A. Does this action apply to me? 

Table 1 of this preamble lists the 

NESHAP and associated regulated 

industrial source category that is the 

subject of this proposal. Table 1 is not 

intended to be exhaustive, but rather 

provides a guide for readers regarding 

the entities that this proposed action is 

likely to affect. The proposed standards, 

once promulgated, will be directly 

applicable to the affected sources. 

Federal, state, local, and tribal 

government entities would not be 

affected by this proposed action. As 

defined in the Initial List of Categories 

of Sources Under Section 112(c)(1) of 

the Clean Air Act Amendments of 1990 

(see 57 FR 31576, July 16, 1992), the 

Portland Cement Manufacturing 

Industry source category is any facility 

engaged in manufacturing Portland 

cement by either the wet or dry process. 

The category includes, but is not limited 

to, the following process units: Kiln, 

clinker cooler, raw mill system, finish 

mill system, raw mill dryer, raw 

material storage, clinker storage, 

finished product storage, conveyor 

transfer points, bagging, and bulk 

loading and unloading systems. 


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44256 Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules 

TABLE 1—NESHAP AND INDUSTRIAL SOURCE CATEGORIES AFFECTED BY THIS PROPOSED ACTION

Source category NESHAP NAICS code 1

Portland cement manufacturing facilities ................................. 40 CFR part 63 subpart LLL ................................................... 327310 

1 North American Industry Classification System. 

The source category does not include 

those kilns that burn hazardous waste 

and are subject to and regulated under 

40 CFR part 63, subpart EEE, or kilns 

that burn solid waste and are subject to 

the Commercial and Industrial Solid 

Waste Incinerator (CISWI) rule under 40 

CFR part 60, subparts CCCC and DDDD. 

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 action 

is available on the Internet. Following 

signature by the EPA Administrator, the 

EPA will post a copy of this proposed 

action at https://www3.epa.gov/ 

airquality/cement/actions.html. 

Following publication in the Federal 

Register, the EPA will post the Federal 

Register version of the proposal and key 

technical documents at this same Web 

site. Information on the overall RTR 

program is available at https://

www3.epa.gov/ttn/atw/rrisk/rtrpg.html. 

C. What should I consider as I prepare 

my comments for the EPA? 

Submitting CBI. Do not submit 

information containing CBI to the EPA 

through http://www.regulations.gov or 

email. 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 the EPA, mark the 

outside of the disk or CD–ROM as CBI 

and then identify electronically within 

the disk or CD–ROM the specific 

information that is claimed as CBI. In 

addition to one complete version of the 

comments that includes information 

claimed as CBI, you must submit a copy 

of the comments that does not contain 

the information claimed as CBI 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 the 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 Code of Federal 

Regulations (CFR) part 2. Send or 

deliver information identified as CBI 

only to the following address: OAQPS 

Document Control Officer (C404–02), 

OAQPS, U.S. Environmental Protection 

Agency, Research Triangle Park, North 

Carolina 27711, Attention Docket ID No. 

EPA–HQ–OAR–2016–0442. 

II. Background 

A. What is the statutory authority for 

this action? 

Section 112 of the CAA establishes a 

two-stage regulatory process to address 

emissions of HAP from stationary 

sources. In the first stage, after the EPA 

has identified categories of sources 

emitting one or more of the HAP listed 

in CAA section 112(b), CAA section 

112(d) requires us to promulgate 

technology-based NESHAP for those 

sources. ‘‘Major sources’’ are those that 

emit or have the potential to emit 10 

tons per year (tpy) or more of a single 

HAP or 25 tpy or more of any 

combination of HAP. For major sources, 

the technology-based NESHAP 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 must reflect the 

maximum degree of emissions reduction 

achievable through the application of 

measures, processes, methods, systems, 

or techniques, including, but not limited 

to, measures that: (1) Reduce the volume 

of or eliminate pollutants through 

process changes, substitution of 

materials, or other modifications; (2) 

enclose systems or processes to 

eliminate emissions; (3) capture or treat 

pollutants when released from a 

process, stack, storage, or fugitive 

emissions point; (4) are design, 

equipment, work practice, or 

operational standards (including 

requirements for operator training or 

certification); or (5) are a combination of 

the above. CAA section 112(d)(2)(A)– 

(E). The MACT standards may take the 

form of design, equipment, work 

practice, or operational standards where 

the EPA first determines either that: (1) 

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 (2) the application of 

measurement methodology to a 

particular class of sources is not 

practicable due to technological and 

economic limitations. CAA section 

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 emissions control that is 

achieved in practice by the bestcontrolled similar source. The MACT 

floor for existing sources can be less 

stringent than floors for new sources, 

but not less stringent than the average 

emissions 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 subcategories with fewer 

than 30 sources). In developing MACT 

standards, the EPA must also consider 

control options that are more stringent 

than the floor. We may establish 

standards more stringent than the floor 

based on considerations of the cost of 

achieving the emission reductions, any 

non-air quality health and 

environmental impacts, and energy 

requirements. 

The EPA is then required to review 

these technology-based standards and 

revise them ‘‘as necessary (taking into 

account developments in practices, 

processes, and control technologies)’’ no 

less frequently than every 8 years. CAA 

section 112(d)(6). In conducting this 

review, the EPA is not required to 

recalculate the MACT floor. Natural 

Resources Defense Council (NRDC) v. 

EPA, 529 F.3d 1077, 1084 (D.C. Cir. 

2008). Association of Battery Recyclers, 

Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 

2013). 

The second stage in standard-setting 

focuses on reducing any remaining (i.e., 

‘‘residual’’) risk according to CAA 

section 112(f). Section 112(f)(1) of the 

CAA required that the EPA prepare a 

report to Congress discussing (among 

other things) methods of calculating the 

risks posed (or potentially posed) by 

sources after implementation of the 

MACT standards, the public health 

significance of those risks, and the 

EPA’s recommendations as to legislation 

regarding such remaining risk. The EPA 

prepared and submitted the Residual 

Risk Report to Congress, EPA–453/R– 

99–001 (Risk Report) in March 1999. 


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Section 112(f)(2) of the CAA then 

provides that if Congress does not act on 

any recommendation in the Risk Report, 

the EPA must analyze and address 

residual risk for each category or 

subcategory of sources 8 years after 

promulgation of such standards 

pursuant to CAA section 112(d). 

Section 112(f)(2) of the CAA requires 

the EPA to determine for source 

categories subject to MACT standards 

whether promulgation of additional 

standards is needed to provide an ample 

margin of safety to protect public health. 

Section 112(f)(2)(B) of the CAA 

expressly preserves the EPA’s use of the 

two-step process for developing 

standards to address any residual risk 

and the Agency’s interpretation of 

‘‘ample margin of safety’’ developed in 

the National Emissions 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 

EPA notified Congress in the Risk 

Report that the Agency intended to use 

the Benzene NESHAP approach in 

making CAA section 112(f) residual risk 

determinations (EPA–453/R–99–001, p. 

ES–11). The EPA subsequently adopted 

this approach in its residual risk 

determinations and in a challenge to the 

risk review for the Synthetic Organic 

Chemical Manufacturing source 

category, the United States Court of 

Appeals for the District of Columbia 

Circuit (the Court) upheld as reasonable 

the EPA’s interpretation that CAA 

section 112(f)(2) incorporates the 

approach established in the Benzene 

NESHAP. See NRDC v. EPA, 529 F.3d 

1077, 1083 (D.C. Cir. 2008) 

(‘‘[S]ubsection 112(f)(2)(B) expressly 

incorporates the EPA’s interpretation of 

the Clean Air Act from the Benzene 

standard, complete with a citation to the 

Federal Register.’’); see also, A 

Legislative History of the Clean Air Act 

Amendments of 1990, vol. 1, p. 877 

(Senate debate on Conference Report). 

The first step in the process of 

evaluating residual risk is the 

determination of acceptable risk. If risks 

are unacceptable, the EPA cannot 

consider cost in identifying the 

emissions standards necessary to bring 

risks to an acceptable level. The second 

step is the determination of whether 

standards must be further revised in 

order to provide an ample margin of 

safety to protect public health. The 

ample margin of safety is the level at 

which the standards must be set, unless 

an even more stringent standard is 

necessary to prevent, taking into 

consideration costs, energy, safety, and 

other relevant factors, an adverse 

environmental effect. 

1. Step 1—Determination of 

Acceptability 

The Agency in the Benzene NESHAP 

concluded 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 

‘‘judgment on acceptability cannot be 

reduced to any single factor.’’ Benzene 

NESHAP at 38046. 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’’ (Risk Report at 178, quoting NRDC 

v. EPA, 824 F. 2d 1146, 1165 (D.C. Cir. 

1987) (en banc) (‘‘Vinyl Chloride’’), 

recognizing that our world is not riskfree. 

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 one in 10 thousand, that 

risk level is considered acceptable.’’ 54 

FR at 38045, September 14, 1989. We 

discussed the maximum individual 

lifetime cancer risk (or maximum 

individual risk (MIR)) as being ‘‘the 

estimated 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 

acknowledged that maximum 

individual lifetime cancer risk ‘‘does not 

necessarily reflect the true risk, but 

displays a conservative risk level which 

is an upper-bound that is unlikely to be 

exceeded.’’ Id. 

Understanding that there are both 

benefits and limitations to using the 

MIR as a metric for determining 

acceptability, we acknowledged in the 

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. Further, in the 

Benzene NESHAP, we noted that: 

[p]articular attention will also be accorded to 

the weight of evidence presented in the risk 

assessment of potential carcinogenicity or 

other health effects of a pollutant. While the 

same numerical risk may be estimated for an 

exposure to a pollutant judged to be a known 

human carcinogen, and to a pollutant 

considered a possible human carcinogen 

based on limited animal test data, the same 

weight cannot be accorded to both estimates. 

In considering the potential public health 

effects of the two pollutants, the Agency’s 

judgment on acceptability, including the 

MIR, will be influenced by the greater weight 

of evidence for the known human 

carcinogen. 

Id. at 38046. The Agency also explained 

in the Benzene NESHAP that: 

[i]n establishing a presumption for MIR, 

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 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 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 coemission of pollutants. 

Id. at 38045. 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 noted earlier, in NRDC v. EPA, the 

Court held that CAA section 112(f)(2) 

‘‘incorporates the EPA’s interpretation 

of the Clean Air Act from the Benzene 

Standard.’’ The Court further held that 

Congress’ incorporation of the Benzene 

standard applies equally to carcinogens 

and non-carcinogens. 529 F.3d at 1081– 

82. Accordingly, we also consider noncancer risk metrics in our determination 

of risk acceptability and ample margin 

of safety. 

2. Step 2—Determination of Ample 

Margin of Safety 

Section 112(f)(2) of the CAA requires 

the EPA to determine, for source 

categories subject to MACT standards, 

whether those standards provide an 

ample margin of safety to protect public 

health. As explained in the Benzene 

NESHAP, ‘‘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 * * *. 

Beyond that information, additional 

factors relating to the appropriate level 

of control will also be considered, 

including costs and economic impacts 

of controls, technological feasibility, 

uncertainties, and any other relevant 

factors. Considering all of these factors, 

the agency will establish the standard at 


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44258 Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules 

1 ‘‘Adverse environmental effect’’ is defined 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. CAA section 112(a)(7). 

a level that provides an ample margin of 

safety to protect the public health, as 

required by section 112.’’ 54 FR 38046, 

September 14, 1989. 

According to CAA section 

112(f)(2)(A), 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 one in one 

million,’’ the 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, the 

EPA may adopt standards equal to 

existing MACT standards if the EPA 

determines that the existing standards 

(i.e., the MACT standards) are 

sufficiently protective. NRDC v. EPA, 

529 F.3d 1077, 1083 (D.C. Cir. 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.’’) The EPA must also adopt 

more stringent standards, if necessary, 

to prevent an adverse environmental 

effect,1 but must consider cost, energy, 

safety, and other relevant factors in 

doing so. 

The CAA does not specifically define 

the terms ‘‘individual most exposed,’’ 

‘‘acceptable level,’’ and ‘‘ample margin 

of safety.’’ In the Benzene NESHAP, 54 

FR at 38044–38045, September 14, 1989, 

we stated as an overall objective: 

In protecting public health with an ample 

margin of safety under section 112, EPA 

strives 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 

plant would have if he or she were exposed 

to the maximum pollutant concentrations for 

70 years. 

The Agency further stated that ‘‘[t]he 

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 risks 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.’’ Id. at 

38045. 

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, 

including the incremental risk reduction 

associated with standards more 

stringent than the MACT standard or a 

more stringent standard that the EPA 

has determined is necessary to ensure 

risk is acceptable. In the ample margin 

of safety analysis, the Agency considers 

additional factors, including costs and 

economic impacts of controls, 

technological 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, September 14, 1989. 

B. What is this source category and how 

does the current NESHAP regulate its 

HAP emissions? 

The EPA initially promulgated the 

Portland Cement Manufacturing 

Industry NESHAP on June 14, 1999 (64 

FR 31898), under title 40, part 63, 

subpart LLL of the CFR (40 CFR part 63, 

subpart LLL). The rule was amended on 

April 5, 2002 (67 FR 16614); July 5, 

2002 (67 FR 44766); December 6, 2002 

(67 FR 72580); December 20, 2006 (71 

FR 76518); September 9, 2010 (75 FR 

54970); January 18, 2011 (76 FR 2832); 

February 12, 2013 (78 FR 10006); July 

27, 2015 (80 FR 44772); September 11, 

2015 (80 FR 54728); and July 25, 2016 

(81 FR 48356). The amendments further 

defined affected cement kilns as those 

used to manufacture Portland cement, 

except for kilns that burn hazardous 

waste, and are subject to and regulated 

under 40 CFR part 63, subpart EEE, and 

kilns that burn solid waste, which are 

subject to the CISWI rule under 40 CFR 

part 60, subparts CCCC and DDDD. 

Additionally, onsite sources that are 

subject to standards for nonmetallic 

mineral processing plants in 40 CFR 

part 60, subpart OOO are not subject to 

40 CFR part 63, subpart LLL. Crushers 

are not covered by 40 CFR part 63, 

subpart LLL regardless of their location. 

Subpart LLL NESHAP regulates HAP 

emissions from new and existing 

Portland cement production facilities 

that are major or area sources of HAP, 

with one exception. Kilns located at 

facilities that are area sources, are not 

regulated for hydrochloric acid (HCl) 

emissions. 

Portland cement manufacturing is an 

energy-intensive process in which 

cement is made by grinding and heating 

a mixture of raw materials such as 

limestone, clay, sand, and iron ore in a 

rotary kiln. The kiln is a large furnace 

that is fueled by coal, oil, gas, coke, and/ 

or various waste materials. The product 

(known as clinker) from the kiln is 

cooled, ground, and then mixed with a 

small amount of gypsum to produce 

Portland cement. 

The main source of air toxics 

emissions from a Portland cement plant 

is the kiln. Emissions originate from the 

burning of fuels and heating of feed 

materials. Air toxics are also emitted 

from the grinding, cooling, and 

materials handling steps in the 

manufacturing process. Pollutants 

regulated under the subpart LLL 

NESHAP are particulate matter (PM) as 

a surrogate for non-mercury HAP 

metals, total hydrocarbons (THC) as a 

surrogate for organic HAP other than 

dioxins and furans (D/F), organic HAP 

as an alternative to the limit for THC, 

mercury, HCl (from major sources only), 

and D/F expressed as toxic equivalents 

(TEQ). The kiln is regulated for all HAP 

and raw material dryers are regulated 

for THC or the alternative organic HAP. 

Clinker coolers are regulated for PM. 

Finish mills and raw mills are regulated 

for opacity. During periods of startup 

and shutdown, the kiln, clinker cooler, 

and raw material dryer are regulated by 

work practices. Open clinker storage 

piles are regulated by work practices. 

The emission standards for the affected 

sources are summarized in Table 2. 

TABLE 2—EMISSION LIMITS FOR KILNS, CLINKER COOLERS, RAW MATERIAL DRYERS, RAW AND FINISH MILLS

If your source is a (an): And the operating mode is: And it is located at a: Your emissions limits are: And the units of the 

emissions limit are: 

The oxygen 

correction 

factor is: 

1. Existing kiln ...................... Normal operation ................ Major or area source .......... PM 1 0.07 ............................ Pounds (lb)/ton clinker ........ NA. 


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TABLE 2—EMISSION LIMITS FOR KILNS, CLINKER COOLERS, RAW MATERIAL DRYERS, RAW AND FINISH MILLS—Continued 

If your source is a (an): And the operating mode is: And it is located at a: Your emissions limits are: And the units of the 

emissions limit are: 

The oxygen 

correction 

factor is: 

D/F 2 0.2 .............................. Nanograms/dry standard 

cubic meters (ng/dscm) 

(TEQ).

7 percent. 

Mercury 55 .......................... lb/million (MM) tons clinker NA. 

THC 3 4 24 ........................... Parts per million, volumetric 

dry (ppmvd).

7 percent. 

2. Existing kiln ...................... Normal operation ................ Major source ....................... HCl 3 ................................... ppmvd ................................. 7 percent. 

3. Existing kiln ...................... Startup and shutdown ........ Major or area source .......... Work practices ....................

(63.1346(g)) ........................

NA ....................................... NA. 

4. New kiln ........................... Normal operation ................ Major or area source .......... PM 1 0.02 ............................ lb/ton clinker ....................... NA. 

D/F 2 0.2 .............................. ng/dscm (TEQ) ................... 7 percent. 

Mercury 21 .......................... lb/MM tons clinker .............. NA. 

THC 3 4 24 ........................... ppmvd ................................. 7 percent. 

5. New kiln ........................... Normal operation ................ Major source ....................... HCl 3 ................................... ppmvd ................................. 7 percent. 

6. New kiln ........................... Startup and shutdown ........ Major or area source .......... Work practices ....................

(63.1346(g)) ........................

NA ....................................... NA. 

7. Existing clinker cooler ...... Normal operation ................ Major or area source .......... PM 0.07 .............................. lb/ton clinker ....................... NA. 

8. Existing clinker cooler ...... Startup and shutdown ........ Major or area source .......... Work practices 

(63.1348(b)(9)).

NA ....................................... NA. 

9. New clinker cooler ........... Normal operation ................ Major or area source .......... PM 0.02 .............................. lb/ton clinker ....................... NA. 

10. New clinker cooler ......... Startup and shutdown ........ Major or area source .......... Work practices 

(63.1348(b)(9)).

NA ....................................... NA. 

11. Existing or new raw material dryer.Normal operation ................ Major or area source .......... THC 3 4 24 ........................... ppmvd ................................. NA. 

12. Existing or new raw material dryer.Startup and shutdown ........ Major or area source .......... Work practices 

(63.1348(b)(9)).

NA ....................................... NA. 

13. Existing or new raw or 

finish mill.

All operating modes ............ Major source ....................... Opacity 10 .......................... percent ................................ NA. 

1The initial and subsequent PM performance tests are performed using Method 5 or 5I and consist of three test runs. 

2 If the average temperature at the inlet to the first PM control device (fabric filter or electrostatic precipitator) during the D/F performance test is 400 °F or less, this 

limit is changed to 0.40 ng/dscm (TEQ). 3 Measured as propane. 

4Any source subject to the 24 ppmvd THC limit may elect to meet an alternative limit of 12 ppmvd for total organic HAP. 

C. What data collection activities were 

conducted to support this action? 

For the Portland Cement 

Manufacturing Industry source category, 

we did not submit data collection 

requests to the industry or request 

emissions testing by the industry for the 

information used in this analysis. The 

data and data sources used to support 

this action are described in section II.D 

below. 

D. What other relevant background 

information and data are available? 

For the Portland Cement 

Manufacturing Industry source category, 

a comprehensive list of facilities and 

kilns was compiled using information 

from the EPA’s Greenhouse Gas 

Reporting Program (GHGRP) (https://

www.epa.gov/ghgreporting). All 

manufacturers of Portland cement are 

required to report annually their 

greenhouse gas emissions to the EPA (40 

CFR part 98, subpart H). In reporting 

year 2015, 95 Portland cement facilities 

reported under the GHGRP. As 

explained above in section II.B, kilns 

that are fueled by hazardous waste are 

subject to the hazardous waste 

regulations in 40 CFR part 63, subpart 

EEE and, therefore, are not subject to 40 

CFR part 63, subpart LLL. Kilns that are 

fueled by solid waste are subject to 

regulations in 40 CFR part 60, subpart 

CCCC or DDDD and are also not subject 

to subpart LLL. To assist in the 

identification of which sources are 

subject to subpart LLL, the 

comprehensive list of Portland cement 

manufacturing facilities was submitted 

to the Portland Cement Association 

(PCA) for review. The PCA is an 

organization that represents the 

manufacturers of cement. The PCA 

provided information on the status of 

each kiln and clinker cooler, whether or 

not they were subject to subpart LLL 

regulations, and identified other sources 

at facilities, such as raw material dryers, 

that were also subject to subpart LLL. 

The risk modeling dataset was 

developed in a two-step process. 

Initially, a draft dataset was developed 

using available information on 

emissions, stack parameters, and 

emission source locations. In step two, 

the draft dataset for each Portland 

cement manufacturing facility was 

submitted to the facility or its parent 

company to review for accuracy. Based 

on the review by each company and the 

submittal of documentation supporting 

the changes, the risk modeling dataset 

was revised. Copies of the datasets sent 

to the companies for review and the 

revised datasets and supporting 

documentation submitted by each 

company are contained in the docket to 

this rulemaking (Docket ID No. EPA– 

HQ–OAR–2016–0442). 

The initial draft dataset was 

developed using emission test data to 

the extent possible. Under 40 CFR part 

63, subpart LLL, the EPA requires that 

performance test results be submitted to 

the EPA via the Compliance and 

Emissions Data Reporting Interface 

(CEDRI), which can be accessed through 

the EPA’s Central Data Exchange (CDX). 

Emissions data are publicly available 

through the EPA’s Web Factor 

Information Retrieval System (WebFIRE) 

using the EPA’s electronic reporting tool 

(ERT) as listed on the EPA’s ERT Web 

site (https://www.epa.gov/electronicreporting-air-emissions/electronicreporting-tool-ert). To estimate actual 

emissions, available emissions data 

were extracted from each facility’s 

submitted ERT file. When emissions 

data were not available in ERT, the 

subpart LLL emissions limit was 

substituted as a placeholder for actual 

emissions until the data set could be 

reviewed and revised by industry. 

III. Analytical Procedures 

In this section, we describe the 

analyses performed to support the 

proposed decisions for the RTR and 

other issues addressed in this proposal. 


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2U.S. EPA SAB. Risk and Technology Review 

(RTR) Risk Assessment Methodologies: For Review 

by the EPA’s Science Advisory Board with Case 

Studies—MACT I Petroleum Refining Sources and 

Portland Cement Manufacturing, May 2010. 

A. How did we estimate post-MACT 

risks posed by the source category? 

The EPA conducted a risk assessment 

that provides estimates of the MIR 

posed by the HAP emissions from each 

source in the source category, the 

hazard index (HI) for chronic exposures 

to HAP with the potential to cause noncancer health effects, and the hazard 

quotient (HQ) for acute exposures to 

HAP with the potential to cause noncancer health effects. The assessment 

also provides estimates of the 

distribution of cancer risks within the 

exposed populations, cancer incidence, 

and an evaluation of the potential for 

adverse environmental effects. The eight 

sections that follow this paragraph 

describe how we estimated emissions 

and conducted the risk assessment. The 

docket for this rulemaking contains the 

following document which provides 

more information on the risk assessment 

inputs and models: Residual Risk 

Assessment for the Portland Cement 

Manufacturing Industry Source 

Category in Support of the Risk and 

Technology Review September, 2017 

Proposed Rule. The methods used to 

assess risks (as described in the eight 

primary steps below) are consistent with 

those peer-reviewed by a panel of the 

EPA’s Science Advisory Board (SAB) in 

2009 and described in their peer review 

report issued in 2010;2 they are also 

consistent with the key 

recommendations contained in that 

report. 

1. How did we estimate actual 

emissions and identify the emissions 

release characteristics? 

The pollutants regulated under 40 

CFR part 63, subpart LLL are PM, HCl, 

THC, mercury, and D/F. The emission 

standards apply to Portland cement 

plants that are major or area sources, 

with one exception. Kilns that are 

located at a facility that is an area source 

are not subject to the emission limits for 

HCl. Sources subject to the emissions 

limit for THC may elect to meet an 

alternative limit for total organic HAP. 

For purposes of subpart LLL, total 

organic HAP is the sum of the 

concentrations of compounds of 

formaldehyde, benzene, toluene, 

styrene, m-xylene, p-xylene, o-xylene, 

acetaldehyde, and naphthalene as 

measured by EPA Test Method 320 or 

Method 18 of appendix A to 40 CFR part 

63 or ASTM D6348–03 or a combination 

of these methods, as appropriate. The 

affected sources at Portland cement 

plants that were accounted for in the 

risk modeling dataset include the kiln, 

as well as any alkali bypass or inline 

raw mill or inline coal mill, clinker 

coolers, and raw material dryers. Kilns 

fueled with hazardous waste or solid 

waste and not subject to subpart LLL 

were excluded from the dataset. All 

affected sources in the risk modeling 

dataset emit through stacks. As 

mentioned in section II.D above, the risk 

modeling dataset used for estimating 

actual emissions was developed in a 

two-step process. Initially, the dataset 

was developed using available 

information and is described below. The 

dataset for each Portland cement 

manufacturing facility was then 

submitted to the facility, or its parent 

company, to review for accuracy. Based 

on the review by each company, and the 

submittal of documentation supporting 

the changes, the risk modeling dataset 

was then revised. Copies of the datasets 

sent to the companies for review and the 

revised datasets submitted by each 

company are contained in the docket to 

this rulemaking (Docket ID No. EPA– 

HQ–OAR–2016–0442). 

As described in section II.D above, 

available emissions data were extracted 

from each facility’s submitted ERT file. 

To ensure that the emissions data reflect 

process and control device changes 

made at each Portland cement plant to 

comply with the 2013 final amendments 

to 40 CFR part 63, subpart LLL 

(February 12, 2013, 78 FR 10006), 

emissions data from mid-2015 and later 

were used as inputs into the emissions 

modeling file. 

Emissions data are reported in ERT in 

units of pounds per hour (lb/hr), which 

were multiplied by a facility’s reported 

annual hours of operation to calculate 

emissions in tpy. If hours of operation 

were not reported, the default of 8,760 

hours per year was used. When 

emissions data were not available in 

ERT, the 40 CFR part 63, subpart LLL 

emissions limit was substituted as a 

placeholder for actual emissions until 

the data set could be reviewed and 

revised by industry. 

Subpart LLL of 40 CFR part 63 uses 

PM as a surrogate for non-mercury 

metallic HAP and THC as a surrogate for 

organic HAP. The specific non-mercury 

metallic HAP that went into the 

modeling file are antimony, arsenic, 

beryllium, cadmium, chromium, cobalt, 

lead, manganese, mercury, nickel, and 

selenium. As an alternative to 

measuring THC, subpart LLL allows 

sources to measure directly their 

emissions of the nine organic HAP 

listed in subpart LLL. The specific 

organic HAP that went into the 

modeling file are acetaldehyde, 

formaldehyde, naphthalene, styrene, 

toluene, m-xylene, o-xylene, p-xylene, 

and benzene. Because subpart LLL 

compliance testing is typically 

performed for the surrogates PM and 

THC, there are limited test data 

available for compound-specific nonmercury metallic and organic HAP 

emissions. To generate compoundspecific metallic HAP and organic HAP 

emissions estimates, recent emissions 

tests were identified in which testing 

was done for compound-specific 

metallic and organic HAP emissions. To 

account for recent changes in emission 

controls and production processes that 

have been implemented by facilities to 

comply with the subpart LLL MACT 

standards, emissions testing that 

occurred in 2015 and later were used to 

develop compound-specific estimates 

for metallic HAP and organic HAP 

emissions. In the case of D/F, the 

subpart LLL emission limits for D/F 

were unchanged in the 2013 final rule. 

Thus, older D/F test data could be used 

along with more recent test data. 

The approach used to develop the 

final risk modeling dataset assures the 

quality of the data at various steps in the 

process of developing the dataset. The 

initial step in developing the dataset 

was to compile a list of affected 

facilities. A comprehensive list of 

cement manufacturing facilities and 

kilns was derived from the EPA’s 

GHGRP, which requires reporting by all 

cement manufacturing facilities. Not all 

Portland cement kilns are subject to 40 

CFR part 63, subpart LLL. Kilns that 

burn commercial and industrial solid 

waste are subject to 40 CFR part 60, 

subpart CCCC and DDDD. Kilns that 

burn hazardous waste are subject to 40 

CFR part 63, subpart EEE. To help 

identify the cement kilns that are 

subject to subpart LLL regulations, the 

list of facilities and kilns was submitted 

to the PCA for review. In their review, 

they provided useful information on 

which cement manufacturing facilities 

were or were not subject to subpart LLL, 

whether kilns and clinker coolers used 

separate or combined stacks, the 

presence of additional affected sources 

not on the initial list, and the presence 

of kilns that were not currently 

operating. For those kilns identified as 

not currently operating, the appropriate 

state permitting agency was contacted to 

determine whether the kiln was 

currently permitted to operate. If the 

kiln was not operating, but retained 

their title V permit, they were kept in 

the dataset. In other instances, company 

representatives were contacted to verify 

that kilns at their facilities were or were 


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3This metric comes from the Benzene NESHAP. 

See 54 FR 38046, September 14, 1989. 

4U.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). 

5A census block is the smallest geographic area 

for which census statistics are tabulated. 

not subject to subpart LLL regulations. 

In developing the emissions data, 

operating hours, stack parameters (i.e., 

stack height, temperature, diameter, 

velocity, and flowrate), and stack 

locations (i.e., latitude and longitude), 

the use of the EPA’s ERT provides a 

single source of electronic test data and 

replaces the manual collection and 

evaluation of test data. The regulated 

facility owner or operator submits their 

summary report semiannually to the 

EPA via the CEDRI, which is accessed 

through the EPA’s CDX (www.epa.gov/ 

cdx). This electronic submission of data 

helps to ensure that information and 

procedures required by test methods are 

documented, provides consistent 

criteria to quantitatively characterize the 

quality of the data collected during the 

emissions test, and standardizes the 

reporting of results. Information on 

stack parameters and stack locations 

were also derived from ERT. For 

facilities that had not yet submitted 

their test information to ERT, the 

emission limits were used as 

placeholders until industry could 

review the information. When operating 

hours were not in ERT, a placeholder of 

8,760 hours was used until industry 

could review the information. When 

stack parameters and stack locations 

were not in ERT, other sources of 

information such as the 2013 Universal 

Industrial Sectors Integrated Solutions 

(UISIS) modeling file created by the 

EPA and the 2011 National Emissions 

Inventory (NEI) were used. As a check 

on the emissions data, operating hours, 

stack parameters, and stack locations 

compiled for each facility, a draft of the 

dataset consisting of the data for all the 

facilities under a single company was 

sent to a representative at the 

appropriate company for review. 

Instructions for reviewing and making 

changes to the dataset required that any 

revisions be supported with appropriate 

documentation. In addition, example 

calculations for emissions estimates and 

default stack parameters were provided. 

Revisions made to the data for each 

facility were incorporated into a master 

final dataset. The master final dataset 

was subjected to further quality 

evaluation. For example, exhaust gas 

flowrates were checked using 

information on stack diameters and gas 

velocities. Stack diameters and stack 

velocities are checked for outliers. Stack 

locations were also checked using 

Google Earth® to ensure that stack 

locations were correctly located at the 

cement manufacturing facility. 

The derivation of actual emission 

estimates is discussed in more detail in 

the document, Development of the RTR 

Risk Modeling Dataset for the Portland 

Cement Manufacturing Industry Source 

Category, which is available in the 

docket for this proposed rulemaking. 

2. How did we estimate MACTallowable emissions? 

The available emissions data in the 

RTR emissions dataset include estimates 

of the mass of HAP emitted during the 

specified annual time period. In some 

cases, these ‘‘actual’’ emission levels are 

lower than the emission levels required 

to comply with the current MACT 

standards. The emissions level allowed 

to be emitted by the MACT standards is 

referred to as the ‘‘MACT-allowable’’ 

emissions level. We discussed the use of 

both MACT-allowable and actual 

emissions in the final Coke Oven 

Batteries RTR (70 FR 19998–19999, 

April 15, 2005) and in the proposed and 

final Hazardous Organic NESHAP RTRs 

(71 FR 34428, June 14, 2006, and 71 FR 

76609, December 21, 2006, 

respectively). In those actions, we noted 

that assessing the risks at the MACTallowable level is inherently reasonable 

since these risks reflect the maximum 

level facilities could emit and still 

comply with national emission 

standards. 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 approach 

(54 FR 38044, September 14, 1989). 

Allowable emissions are calculated 

using the emission limits in the rule for 

existing sources along with the emission 

factors for metallic HAP, organic HAP, 

and D/F congeners, the annual 

production capacity, and, when the 

emission limit is a concentration-based 

limit, the annual hours of operation 

reported by each source. We note that 

these are conservative estimates of 

allowable emissions. It is unlikely that 

emissions would be at the maximum 

limit at all times because sources cannot 

emit HAP at a level that is exactly equal 

to the limit and remain in compliance 

with the standard due to day-to-day 

variability in process operations and 

emissions. On average, facilities must 

emit at some level below the MACT 

limit to ensure that they are always in 

compliance. The derivation of allowable 

emissions is discussed in more detail in 

the document, Development of the RTR 

Risk Modeling Dataset for the Portland 

Cement Manufacturing Industry Source 

Category, which is available in the 

docket for this proposed rulemaking. 

3. How did we conduct dispersion 

modeling, determine inhalation 

exposures, and estimate individual and 

population inhalation risks? 

Both long-term and short-term 

inhalation exposure concentrations and 

health risks from the source category 

addressed in this proposal were 

estimated using the Human Exposure 

Model (Community and Sector HEM–3). 

The HEM–3 performs three primary risk 

assessment activities: (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 kilometers (km) of 

the modeled sources,3 and (3) 

estimating individual and populationlevel inhalation risks using the exposure 

estimates and quantitative doseresponse information. 

The air dispersion model used by the 

HEM–3 model (AERMOD) is one of the 

EPA’s preferred models for assessing 

pollutant concentrations from industrial 

facilities.4 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 (2016) of hourly surface and upper 

air observations for more than 800 

meteorological stations, selected to 

provide coverage of the U.S. and Puerto 

Rico. A second library of U.S. Census 

Bureau census block 5 internal point 

locations and populations provides the 

basis of human exposure calculations 

(U.S. Census, 2010). In addition, for 

each census block, the census library 

includes the elevation and controlling 

hill height, 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 the EPA for HAP and 

other toxic air pollutants. These values 

are available at https://www.epa.gov/

fera/dose-response-assessmentassessing-health-risks-associatedexposure-hazardous-air-pollutants and 

are discussed in more detail later in this 

section. 

In developing the risk assessment for 

chronic exposures, we used the 


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6These 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). In August 2000, 

the document, Supplemental Guidance for 

Conducting Health Risk Assessment of Chemical 

Mixtures (EPA/630/R–00/002) was published as a 

supplement to the 1986 document. Copies of both 

documents can be obtained from https://cfpub.

epa.gov/ncea/risk/recordisplay.cfm?deid=20533&

CFID=70315376&CFTOKEN=71597944. 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 the EPA’s National Air Toxics Assessment 

(NATA) titled, NATA—Evaluating the Nationalscale Air Toxics Assessment 1996 Data—an SAB 

Advisory, available at http://yosemite.epa.gov/sab/

sabproduct.nsf/214C6E915BB04E14852570

CA007A682C/$File/ecadv02001.pdf. 

7Recommendations from the SAB’s review of 

RTR Risk Assessment Methodologies and the 

review materials are available at http://yosemite.

epa.gov/sab/sabproduct.nsf/4AB3966E263

D943A8525771F00668381/$File/EPA-SAB-10-007-

unsigned.pdf and at https://cfpub.epa.gov/si/si_

publiclowbar;record_report.cfm?dirEntryID=

238928, respectively. 

estimated annual average ambient air 

concentrations of each 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 

continuous lifetime (24 hours per day, 

7 days per week, and 52 weeks per year 

for a 70-year period) exposure to the 

maximum concentration at the centroid 

of inhabited census blocks. Individual 

cancer risks were calculated by 

multiplying the estimated lifetime 

exposure to the ambient concentration 

of each of the HAP (in micrograms per 

cubic meter (mg/m3)) by its unit risk 

estimate (URE). The URE 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 per 

cubic meter of air. For residual risk 

assessments, we generally use URE 

values from the EPA’s Integrated Risk 

Information System (IRIS). For 

carcinogenic pollutants without IRIS 

values, we look to other reputable 

sources of cancer dose-response values, 

often using California EPA (CalEPA) 

URE values, where available. In cases 

where new, scientifically credible dose 

response values have been developed in 

a manner consistent with the EPA 

guidelines and have undergone a peer 

review process similar to that used by 

the EPA, we may use such doseresponse values in place of, or in 

addition to, other values, if appropriate. 

The EPA estimated incremental 

individual lifetime cancer risks 

associated with emissions from the 

facilities in the source category 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 

potential 6) emitted by the modeled 

sources. Cancer incidence and the 

distribution of individual cancer risks 

for the population within 50 km of the 

sources were also estimated for the 

source category as part of this 

assessment by summing individual 

risks. A distance of 50 km is consistent 

with both the analysis supporting the 

1989 Benzene NESHAP (54 FR 38044, 

September 14, 1989) and the limitations 

of Gaussian dispersion models, 

including AERMOD. 

To assess the 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 value, which is a value 

selected from one of several sources. 

First, the chronic reference level can be 

the EPA reference concentration (RfC) 

(https://iaspub.epa.gov/sor_internet/

registry/termreg/searchandretrieve/

glossariesandkeywordlists/search.do?

details=&vocabName=

IRIS%20Glossary), 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.’’ Alternatively, in 

cases where an RfC from the EPA’s IRIS 

database is not available or where the 

EPA determines that using a value other 

than the RfC is appropriate, the chronic 

reference level can be a value from the 

following prioritized sources: (1) The 

Agency for Toxic Substances and 

Disease Registry (ATSDR) Minimal Risk 

Level (MRL) (http://www.atsdr.cdc.gov/ 

mrls/index.asp), which is defined as ‘‘an 

estimate of daily human exposure to a 

hazardous substance that is likely to be 

without an appreciable risk of adverse 

non-cancer health effects (other than 

cancer) over a specified duration of 

exposure’’; (2) the CalEPA Chronic 

Reference Exposure Level (REL) (http:// 

oehha.ca.gov/air/crnr/notice-adoptionair-toxics-hot-spots-program-guidancemanual-preparation-health-risk-0), 

which is defined as ‘‘the concentration 

level (that is expressed in units of 

mg/m3 for inhalation exposure and in a 

dose expressed in units of milligram per 

kilogram-day (mg/kg-day) for oral 

exposures), at or below which no 

adverse health effects are anticipated for 

a specified exposure duration’’; or (3), as 

noted above, a scientifically credible 

dose-response value that has been 

developed in a manner consistent with 

the EPA guidelines and has undergone 

a peer review process similar to that 

used by the EPA, in place of or in 

concert with other values. 

As mentioned above, in order to 

characterize non-cancer chronic effects, 

and in response to key 

recommendations from the SAB, the 

EPA selects dose-response values that 

reflect the best available science for all 

HAP included in RTR risk assessments.7

More specifically, for a given HAP, the 

EPA examines the availability of 

inhalation reference values from the 

sources included in our tiered approach 

(e.g., IRIS first, ATSDR second, CalEPA 

third) and determines which inhalation 

reference value represents the best 

available science. Thus, as new 

inhalation reference values become 

available, the EPA will typically 

evaluate them and determine whether 

they should be given preference over 

those currently being used in RTR risk 

assessments. 

The EPA also evaluated screening 

estimates of acute exposures and risks 

for each of the HAP (for which 

appropriate acute dose-response values 

are available) at the point of highest 

potential off-site exposure for each 

facility. To do this, the EPA estimated 

the risks when both the peak hourly 

emissions rate and worst-case 

dispersion conditions occur. We also 

assume that a person is located at the 

point of highest impact during that same 

time. In accordance with our mandate in 

section 112 of the CAA, we use the 

point of highest off-site exposure to 

assess the potential risk to the 

maximally exposed individual. The 

acute HQ is the estimated acute 

exposure divided by the acute doseresponse value. In each case, the EPA 

calculated acute HQ values using best 

available, short-term dose-response 

values. These acute dose-response 

values, which are described below, 

include the acute 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 emissions rates, 

meteorology, and exposure location. 

As described in the CalEPA’s Air 

Toxics Hot Spots Program Risk 


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8National Academy of Sciences (NAS), 2001. 

Standing Operating Procedures for Developing 

Acute Exposure Levels for Hazardous Chemicals, 

page 2. 

9ERP Committee Procedures and Responsibilities. 

March 2014. American Industrial Hygiene 

Association. 

Assessment Guidelines, Part I, The 

Determination of Acute Reference 

Exposure Levels for Airborne Toxicants, 

an acute REL value (http://oehha.ca.

gov/air/general-info/oehha-acute-8- 

hour-and-chronic-reference-exposurelevel-rel-summary) is defined as ‘‘the 

concentration level at or below which 

no adverse health effects are anticipated 

for a specified exposure duration.’’ Id. at 

page 2. Acute REL values are based on 

the most sensitive, relevant, adverse 

health effect reported in the peerreviewed medical and toxicological 

literature. Acute REL values are 

designed to protect the most sensitive 

individuals in the population through 

the inclusion of margins of safety. 

Because margins of safety are 

incorporated to address data gaps and 

uncertainties, exceeding the REL does 

not automatically indicate an adverse 

health impact. 

AEGL values were derived in 

response to recommendations from the 

National Research Council (NRC). The 

National Advisory Committee (NAC) for 

the Development of Acute Exposure 

Guideline Levels for Hazardous 

Substances, usually referred to as the 

AEGL Committee or the NAC/AEGL 

committee, developed AEGL values for 

at least 273 of the 329 chemicals on the 

AEGL priority chemical list. The last 

meeting of the NAC/AEGL Committee 

was in April 2010, and its charter 

expired in October 2011. The NAC/ 

AEGL Committee ended in October 

2011, but the AEGL program continues 

to operate at the EPA and works with 

the National Academies to publish final 

AEGLs (https://www.epa.gov/aegl). 

As described in Standing Operating 

Procedures (SOP) of the National 

Advisory Committee on Acute Exposure 

Guideline Levels for Hazardous 

Chemicals (https://www.epa.gov/sites/

production/files/2015–09/documents/

sop_final_standing_operating_

procedures_2001.pdf),8 ‘‘the NRC’s 

previous name for acute exposure 

levels—community emergency exposure 

levels—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.’’ Id. at 2. This document also 

states that AEGL values ‘‘represent 

threshold exposure limits for the general 

public and are applicable to emergency 

exposures ranging from 10 minutes to 

eight hours.’’ Id. at 2. 

The document lays out the purpose 

and objectives of AEGL by stating that 

‘‘the primary purpose of the AEGL 

program and the National Advisory 

Committee for Acute Exposure 

Guideline Levels for Hazardous 

Substances is to develop guideline 

levels for once-in-a-lifetime, short-term 

exposures to airborne concentrations of 

acutely toxic, high-priority chemicals.’’ 

Id. at 21. In detailing the intended 

application of AEGL values, the 

document states that ‘‘[i]t is anticipated 

that the AEGL values will be used for 

regulatory and nonregulatory purposes 

by U.S. 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.’’ Id. at 31. 

The AEGL–1 value is then specifically 

defined as ‘‘the airborne concentration 

(expressed as ppm (parts per million) or 

mg/m3 (milligrams per cubic meter)) 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 cessation of exposure.’’ 

Id. at 3. The document also notes 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.’’ Id. Similarly, the 

document defines AEGL–2 values as 

‘‘the airborne concentration (expressed 

as parts per million or milligrams per 

cubic meter) 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.’’ Id. 

ERPG values are derived for use in 

emergency response, as described in the 

American Industrial Hygiene 

Association’s Emergency Response 

Planning (ERP) Committee document 

titled, ERPGS Procedures and 

Responsibilities (https://www.aiha.org/

get-involved/AIHAGuideline

Foundation/EmergencyResponse

PlanningGuidelines/Documents/ERPG

%20Committee%20Standard%20

Operating%20Procedures%20%20-%20

March%202014%20Revision%20%28

Updated%2010-2-2014%29.pdf), which 

states that, ‘‘Emergency Response 

Planning Guidelines were developed for 

emergency planning and are intended as 

health based guideline concentrations 

for single exposures to chemicals.’’ 9 Id. 

at 1. 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 without perceiving a clearly 

defined, objectionable odor.’’ Id. at 2. 

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 one hour 

without experiencing or developing 

irreversible or other serious health 

effects or symptoms which could impair 

an individual’s ability to take protective 

action.’’ Id. at 1. 

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 because the types of 

effects for these chemicals are not 

consistent with the AEGL–1/ERPG–1 

definitions; in these instances, we 

compare higher severity level AEGL–2 

or ERPG–2 values to our modeled 

exposure levels to screen for potential 

acute concerns. When AEGL–1/ERPG–1 

values are available, they are used in 

our acute risk assessments. 

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 

dose-response value (usually the AEGL– 

1 and/or the ERPG–1 value). 

To develop screening estimates of 

acute exposures in the absence of hourly 

emissions data, generally we first 

develop estimates of maximum hourly 

emissions rates by multiplying the 


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10Allen, et al., 2004. Variable Industrial VOC 

Emissions and their impact on ozone formation in 

the Houston Galveston Area. Texas Environmental 

Research Consortium. https://

www.researchgate.net/publication/237593060_

Variable_Industrial_VOC_Emissions and_their_

Impact_on_Ozone_Formation_in_the_Houston_

Galveston_Area. 

11The SAB peer review of RTR Risk Assessment 

Methodologies is available at http://yosemite.

epa.gov/sab/sabproduct.nsf/4AB3966E263D943A

8525771F00668381/$File/EPA-SAB-10-007-

unsigned.pdf. 

12U.S. EPA. Chapter 2.9, Chemical Specific 

Reference Values for Formaldehyde in Graphical 

Arrays of Chemical-Specific Health Effect Reference 

Values for Inhalation Exposures (Final Report). U.S. 

Environmental Protection Agency, Washington, DC, 

EPA/600/R–09/061, 2009, and available online at 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?

deid=211003. 

average actual annual hourly emissions 

rates by a default factor to cover 

routinely variable emissions. We choose 

the factor to use partially based on 

process knowledge and engineering 

judgment. The factor chosen also 

reflects a Texas study of short-term 

emissions variability, which showed 

that most peak emission events in a 

heavily-industrialized four-county area 

(Harris, Galveston, Chambers, and 

Brazoria Counties, Texas) were less than 

twice the annual average hourly 

emissions rate. The highest peak 

emissions event was 74 times the 

annual average hourly emissions rate, 

and the 99th percentile ratio of peak 

hourly emissions rate to the annual 

average hourly emissions rate was 9.10

Considering this analysis, to account for 

more than 99 percent of the peak hourly 

emissions, we apply a conservative 

screening multiplication factor of 10 to 

the average annual hourly emissions 

rate in our acute exposure screening 

assessments as our default approach. A 

further discussion of why this factor 

was chosen can be found in the 

memorandum, Emissions Data and 

Acute Risk Factor Used in Residual Risk 

Modeling: Portland Cement 

Manufacturing Industry, available in the 

docket for this rulemaking. 

As part of our acute risk assessment 

process, for cases where acute HQ 

values from the screening step are less 

than or equal to 1 (even under the 

conservative assumptions of the 

screening analysis), acute impacts are 

deemed negligible and no further 

analysis is performed for these HAP. In 

cases where an acute HQ from the 

screening step is greater than 1, 

additional site-specific data are 

considered to develop a more refined 

estimate of the potential for acute 

impacts of concern. For this source 

category, since no HQ was greater than 

1, no further analysis was performed. 

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 

emissions 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. Recognizing that this level of 

data is rarely available, we instead rely 

on the multiplier approach. 

To better characterize the potential 

health risks associated with estimated 

acute exposures to HAP, and in 

response to a key recommendation from 

the SAB’s 2010 peer review of the EPA’s 

RTR risk assessment methodologies,11

we generally examine a wider range of 

available acute health metrics (e.g., 

RELs, AEGLs) than we do for our 

chronic risk assessments. This is in 

response to the SAB’s acknowledgement 

that there are generally more data gaps 

and inconsistencies in acute reference 

values than there are in chronic 

reference values. In some cases, when 

Reference Value Arrays 12 for HAP have 

been developed, we consider additional 

acute values (i.e., occupational and 

international values) to provide a more 

complete risk characterization. 

4. How did we conduct the 

multipathway exposure and risk 

screening? 

The EPA conducted a screening 

analysis examining the potential for 

significant human health risks due to 

exposures via routes other than 

inhalation (i.e., ingestion). We first 

determined whether any sources in the 

source category emitted any HAP 

known to be persistent and 

bioaccumulative in the environment 

(PB–HAP). The PB–HAP compounds or 

compound classes are identified for the 

screening from the EPA’s Air Toxics 

Risk Assessment Library (available at 

http://www2.epa.gov/fera/riskassessment-and-modeling-air-toxicsrisk-assessment-reference-library). 

For the Portland Cement 

Manufacturing Industry source category, 

we identified emissions of lead 

compounds, cadmium compounds, 

mercury compounds, arsenic 

compounds, and D/F. Because one or 

more of these PB–HAP are emitted by at 

least one facility in the Portland Cement 

Manufacturing Industry source category, 

we proceeded to the next step of the 

evaluation. In this step, we determined 

whether the facility-specific emission 

rates of the emitted PB–HAP were large 

enough to create the potential for 

significant non-inhalation human health 

risks under reasonable worst-case 

conditions. To facilitate this step, we 

developed screening threshold emission 

rates for several PB–HAP using a 

hypothetical upper-end screening 

exposure scenario developed for use in 

conjunction with the EPA’s Total Risk 

Integrated Methodology.Fate, Transport, 

and Ecological Exposure (TRIM.FaTE) 

model. The PB–HAP with screening 

threshold emission rates are: Cadmium 

compounds, mercury compounds, 

arsenic compounds, and D/F and 

polycyclic organic matter (POM). We 

conducted a sensitivity analysis on the 

screening scenario to ensure that its key 

design parameters would represent the 

upper end of the range of possible 

values, such that it would represent a 

conservative, but not impossible 

scenario. The facility-specific PB–HAP 

emission rates were compared to their 

respective screening threshold emission 

rate to assess the potential for 

significant human health risks via noninhalation pathways. We call this 

application of the TRIM.FaTE model the 

Tier 1 TRIM-screen or Tier 1 screen. 

For the purpose of developing 

emission rates for the Tier 1 TRIMscreen, we derived emission levels for 

these PB–HAP (other than lead 

compounds) at which the maximum 

excess lifetime cancer risk would be 1- 

in-1 million (i.e., D/F, arsenic 

compounds, and POM) or, for HAP that 

cause non-cancer health effects (i.e., 

cadmium compounds and mercury 

compounds), the maximum HQ would 

be 1. If the emission rate of any PB–HAP 

included in the Tier 1 screen exceeds 

the Tier 1 screening threshold emission 

rates for any facility, we conduct a 

second screen, which we call the Tier 2 

TRIM-screen or Tier 2 screen. 

In the Tier 2 screen, the location of 

each facility that exceeds the Tier 1 

screening threshold emission rates is 

used to refine the assumptions 

associated with the environmental 

scenario while maintaining the 

exposure scenario assumptions. A key 

assumption that is part of the Tier 1 

screen is that a lake is located near the 

facility; we confirm the existence of 

lakes near the facility as part of the Tier 

2 screen. We also examine the 

differences between local meteorology 

near the facility and the meteorology 

used in the Tier 1 screen. We then 

adjust the risk-based Tier 1 screening 

threshold emission rates for each PB– 

HAP for each facility based on an 

understanding of how exposure 

concentrations estimated for the 

screening scenario change with 

meteorology and environmental 


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13 In doing so, the EPA notes that the legal 

standard for a primary NAAQS—that a standard is 

requisite to protect public health and provide an 

adequate margin of safety (CAA section 109(b))— 

differs from the CAA section 112(f) standard 

(requiring, among other things, that the standard 

provide an ‘‘ample margin of safety’’). However, the 

Primary Lead NAAQS is a reasonable measure of 

determining risk acceptability (i.e., the first step of 

the Benzene NESHAP analysis) since it is designed 

to protect the most susceptible group in the human 

population—children, including children living 

near major lead emitting sources. 73 FR 67002/3; 73 

FR 67000/3; 73 FR 67005/1. In addition, applying 

the level of the Primary Lead NAAQS at the risk 

acceptability step is conservative, since that 

Primary Lead NAAQS reflects an adequate margin 

of safety. 

14The Secondary Lead NAAQS is a reasonable 

measure of determining whether there is an adverse 

environmental effect since it was established 

considering ‘‘effects on soils, water, crops, 

vegetation, man-made materials, animals, wildlife, 

weather, visibility and climate, damage to and 

deterioration of property, and hazards to 

transportation, as well as effects on economic 

values and on personal comfort and well-being.’’ 

assumptions. PB–HAP emissions that do 

not exceed these new Tier 2 screening 

threshold emission rates are considered 

to be below a level of concern. If the 

PB–HAP emissions for a facility exceed 

the Tier 2 screening threshold emission 

rates and data are available, we may 

decide to conduct a more refined Tier 3 

multipathway assessment or proceed to 

a site-specific assessment. There are 

several analyses that can be included in 

a Tier 3 screen depending upon the 

extent of refinement warranted, 

including validating that the lakes are 

fishable, considering plume-rise to 

estimate emissions lost above the 

mixing layer, and considering hourly 

effects of meteorology and plume rise on 

chemical fate and transport. For this 

source category a Tier 3 screen was 

conducted for 1 facility that had dioxin 

emissions exceeding the Tier 2 

threshold emission rates up to a value 

of 100-in-1 million. If the Tier 3 screen 

is exceeded, the EPA may conduct a 

refined site-specific assessment. 

When tiered screening values for any 

facility indicate a potential health risk 

to the public, we may conduct a more 

refined multipathway assessment. A 

refined assessment was conducted for 

mercury in lieu of conducting a Tier 3 

screen. To select the candidate facilities 

for the site-specific assessment, we 

analyzed the facilities with the 

maximum exceedances of the Tier 2 

screening values as well as the 

combined effect from multiple facilities 

on lakes within the same watershed. In 

addition to looking at the Tier 2 screen 

value for each lake, the location and 

number of lakes or farms impacted for 

each watershed was evaluated to assess 

elevation/topography influences. A 

review of the source category identified 

3 facilities located in Midlothian, Texas, 

as the best candidates for mercury 

impacts. These candidate sites were 

selected because of their exceedances of 

the Tier 2 mercury screening value and 

based upon the above considerations. 

In evaluating the potential 

multipathway risk from emissions of 

lead compounds, rather than developing 

a screening threshold emission rate for 

them, we compared maximum 

estimated 1-hour acute inhalation 

exposures with the level of the current 

National Ambient Air Quality Standard 

(NAAQS) for lead.13 Values below the 

level of the Primary (health-based) Lead 

NAAQS were considered to have a low 

potential for multipathway risk. 

For further information on the 

multipathway analysis approach, see 

the Residual Risk Assessment for the 

Portland Cement Manufacturing 

Industry Source Category in Support of 

the Risk and Technology Review 

September 2017 Proposed Rule, which 

is available in the docket for this action. 

5. How did we assess risks considering 

emissions control options? 

In addition to assessing baseline 

inhalation risks and screening for 

potential multipathway risks, we also 

estimated risks considering the potential 

emission reductions that would be 

achieved by the control options under 

consideration. In these cases, the 

expected emission reductions were 

applied to the specific HAP and 

emission points in the RTR emissions 

dataset to develop corresponding 

estimates of risk and incremental risk 

reductions. 

6. How did we conduct the 

environmental risk screening 

assessment? 

a. Adverse Environmental Effect 

The EPA conducts a screening 

assessment to examine the potential for 

adverse environmental effects as 

required under section 112(f)(2)(A) of 

the CAA. Section 112(a)(7) of the CAA 

defines ‘‘adverse environmental effect’’ 

as ‘‘any significant and widespread 

adverse effect, which may reasonably be 

anticipated, to wildlife, aquatic life, or 

other natural resources, including 

adverse impacts on populations of 

endangered or threatened species or 

significant degradation of 

environmental quality over broad 

areas.’’ 

b. Environmental HAP 

The EPA focuses on eight HAP, which 

we refer to as ‘‘environmental HAP,’’ in 

its screening analysis: Six PB–HAP and 

two acid gases. The six PB–HAP are 

cadmium compounds, D/F, arsenic 

compounds, POM, mercury compounds 

(both inorganic mercury and methyl 

mercury), and lead compounds. The two 

acid gases are HCl and hydrogen 

fluoride (HF). The rationale for 

including these eight HAP in the 

environmental risk screening analysis is 

presented below. 

HAP that persist and bioaccumulate 

are of particular environmental concern 

because they accumulate in the soil, 

sediment, and water. The PB–HAP are 

taken up, through sediment, soil, water, 

and/or ingestion of other organisms, by 

plants or animals (e.g., small fish) at the 

bottom of the food chain. As larger and 

larger predators consume these 

organisms, concentrations of the PB– 

HAP in the animal tissues increases as 

does the potential for adverse effects. 

The six PB–HAP we evaluate as part of 

our screening analysis account for 99.8 

percent of all PB–HAP emissions 

nationally from stationary sources (on a 

mass basis from the 2005 EPA NEI). 

In addition to accounting for almost 

all of the mass of PB–HAP emitted, we 

note that the TRIM.FaTE model that we 

use to evaluate multipathway risk 

allows us to estimate concentrations of 

cadmium compounds, D/F, arsenic 

compounds, POM, and mercury 

compounds in soil, sediment, and 

water. For lead compounds, we 

currently do not have the ability to 

calculate these concentrations using the 

TRIM.FaTE model. Therefore, to 

evaluate the potential for adverse 

environmental effects from lead 

compounds, we compare the estimated 

HEM-modeled exposures from the 

source category emissions of lead with 

the level of the Secondary Lead 

NAAQS.14 We consider values below 

the level of the Secondary Lead NAAQS 

to be unlikely to cause adverse 

environmental effects. 

Due to their well-documented 

potential to cause direct damage to 

terrestrial plants, we include two acid 

gases, HCl and HF, in the environmental 

screening analysis. According to the 

2005 NEI, HCl and HF account for about 

99 percent (on a mass basis) of the total 

acid gas HAP emitted by stationary 

sources in the U.S. In addition to the 

potential to cause direct damage to 

plants, high concentrations of HF in the 

air have been linked to fluorosis in 

livestock. Air concentrations of these 

HAP are already calculated as part of 

the human multipathway exposure and 

risk screening analysis using the HEM3– 

AERMOD air dispersion model, and we 

are able to use the air dispersion 

modeling results to estimate the 


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potential for an adverse environmental 

effect. 

The EPA acknowledges that other 

HAP beyond the eight HAP discussed 

above may have the potential to cause 

adverse environmental effects. 

Therefore, the EPA may include other 

relevant HAP in its environmental risk 

screening in the future, as modeling 

science and resources allow. The EPA 

invites comment on the extent to which 

other HAP emitted by the source 

category may cause adverse 

environmental effects. Such information 

should include references to peerreviewed ecological effects benchmarks 

that are of sufficient quality for making 

regulatory decisions, as well as 

information on the presence of 

organisms located near facilities within 

the source category that such 

benchmarks indicate could be adversely 

affected. 

c. Ecological Assessment Endpoints and 

Benchmarks for PB–HAP 

An important consideration in the 

development of the EPA’s screening 

methodology is the selection of 

ecological assessment endpoints and 

benchmarks. Ecological assessment 

endpoints are defined by the ecological 

entity (e.g., aquatic communities, 

including fish and plankton) and its 

attributes (e.g., frequency of mortality). 

Ecological assessment endpoints can be 

established for organisms, populations, 

communities or assemblages, and 

ecosystems. 

For PB–HAP (other than lead 

compounds), we evaluated the 

following community-level ecological 

assessment endpoints to screen for 

organisms directly exposed to HAP in 

soils, sediment, and water: 

• Local terrestrial communities (i.e., 

soil invertebrates, plants) and 

populations of small birds and 

mammals that consume soil 

invertebrates exposed to PB–HAP in the 

surface soil; 

• Local benthic (i.e., bottom sediment 

dwelling insects, amphipods, isopods, 

and crayfish) communities exposed to 

PB–HAP in sediment in nearby water 

bodies; and 

• Local aquatic (water-column) 

communities (including fish and 

plankton) exposed to PB–HAP in nearby 

surface waters. 

For PB–HAP (other than lead 

compounds), we also evaluated the 

following population-level ecological 

assessment endpoint to screen for 

indirect HAP exposures of top 

consumers via the bioaccumulation of 

HAP in food chains: 

• Piscivorous (i.e., fish-eating) 

wildlife consuming PB–HAPcontaminated fish from nearby water 

bodies. 

For cadmium compounds, D/F, 

arsenic compounds, POM, and mercury 

compounds, we identified the available 

ecological benchmarks for each 

assessment endpoint. An ecological 

benchmark represents a concentration of 

HAP (e.g., 0.77 mg of HAP per liter of 

water) that has been linked to a 

particular environmental effect level 

through scientific study. For PB–HAP 

we identified, where possible, 

ecological benchmarks at the following 

effect levels: 

• Probable effect levels (PEL): Level 

above which adverse effects are 

expected to occur frequently; 

• Lowest-observed-adverse-effect 

level (LOAEL): The lowest exposure 

level tested at which there are 

biologically significant increases in 

frequency or severity of adverse effects; 

and 

• No-observed-adverse-effect levels 

(NOAEL): The highest exposure level 

tested at which there are no biologically 

significant increases in the frequency or 

severity of adverse effect. 

We established a hierarchy of 

preferred benchmark sources to allow 

selection of benchmarks for each 

environmental HAP at each ecological 

assessment endpoint. In general, the 

EPA sources that are used at a 

programmatic level (e.g., Office of 

Water, Superfund Program) were used 

in the analysis, if available. If not, the 

EPA benchmarks used in Regional 

programs (e.g., Superfund) were used. If 

benchmarks were not available at a 

programmatic or Regional level, we 

used benchmarks developed by other 

federal agencies (e.g., National Oceanic 

and Atmospheric Administration 

(NOAA)) or state agencies. 

Benchmarks for all effect levels are 

not available for all PB–HAP and 

assessment endpoints. In cases where 

multiple effect levels were available for 

a particular PB–HAP and assessment 

endpoint, we use all of the available 

effect levels to help us to determine 

whether ecological risks exist and, if so, 

whether the risks could be considered 

significant and widespread. 

d. Ecological Assessment Endpoints and 

Benchmarks for Acid Gases 

The environmental screening analysis 

also evaluated potential damage and 

reduced productivity of plants due to 

direct exposure to acid gases in the air. 

For acid gases, we evaluated the 

following ecological assessment 

endpoint: 

• Local terrestrial plant communities 

with foliage exposed to acidic gaseous 

HAP in the air. 

The selection of ecological 

benchmarks for the effects of acid gases 

on plants followed the same approach 

as for PB–HAP (i.e., we examine all of 

the available chronic benchmarks). For 

HCl, the EPA identified chronic 

benchmark concentrations. We note that 

the benchmark for chronic HCl exposure 

to plants is greater than the reference 

concentration for chronic inhalation 

exposure for human health. This means 

that where the EPA includes regulatory 

requirements to prevent an exceedance 

of the reference concentration for 

human health, additional analyses for 

adverse environmental effects of HCl 

would not be necessary. 

For HF, the EPA identified chronic 

benchmark concentrations for plants 

and evaluated chronic exposures to 

plants in the screening analysis. High 

concentrations of HF in the air have also 

been linked to fluorosis in livestock. 

However, the HF concentrations at 

which fluorosis in livestock occur are 

higher than those at which plant 

damage begins. Therefore, the 

benchmarks for plants are protective of 

both plants and livestock. 

e. Screening Methodology 

For the environmental risk screening 

analysis, the EPA first determined 

whether any facilities in the Portland 

Cement Manufacturing Industry sources 

emitted any of the eight environmental 

HAP. For the Portland Cement 

Manufacturing Industry source category, 

we identified emissions of lead 

compounds, cadmium compounds, 

mercury compounds, arsenic 

compounds, D/F, and HCl. 

Because one or more of the eight 

environmental HAP evaluated are 

emitted by at least one facility in the 

source category, we proceeded to the 

second step of the evaluation. 

f. PB–HAP Methodology 

For cadmium compounds, arsenic 

compounds, mercury compounds, POM, 

and D/F, the environmental screening 

analysis consists of two tiers, while lead 

compounds are analyzed differently as 

discussed earlier. In the first tier, we 

determined whether the maximum 

facility-specific emission rates of each of 

the emitted environmental HAP were 

large enough to create the potential for 

adverse environmental effects under 

reasonable worst-case environmental 

conditions. These are the same 

environmental conditions used in the 

human multipathway exposure and risk 

screening analysis. 

To facilitate this step, TRIM.FaTE was 

run for each PB–HAP under 

hypothetical environmental conditions 

designed to provide conservatively high 


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HAP concentrations. The model was set 

to maximize runoff from terrestrial 

parcels into the modeled lake, which in 

turn, maximized the chemical 

concentrations in the water, the 

sediments, and the fish. The resulting 

media concentrations were then used to 

back-calculate a screening level 

emission rate that corresponded to the 

relevant exposure benchmark 

concentration value for each assessment 

endpoint. To assess emissions from a 

facility, the reported emission rate for 

each PB–HAP was compared to the 

screening level emission rate for that 

PB–HAP for each assessment endpoint. 

If emissions from a facility do not 

exceed the Tier 1 screening level, the 

facility ‘‘passes’’ the screen, and, 

therefore, is not evaluated further under 

the screening approach. If emissions 

from a facility exceed the Tier 1 

screening level, we evaluate the facility 

further in Tier 2. 

In Tier 2 of the environmental 

screening analysis, the emission rate 

screening levels are adjusted to account 

for local meteorology and the actual 

location of lakes in the vicinity of 

facilities that did not pass the Tier 1 

screen. The modeling domain for each 

facility in the Tier 2 analysis consists of 

8 octants. Each octant contains 5 

modeled soil concentrations at various 

distances from the facility (5 soil 

concentrations × 8 octants = total of 40 

soil concentrations per facility) and one 

lake with modeled concentrations for 

water, sediment, and fish tissue. In the 

Tier 2 environmental risk screening 

analysis, the 40 soil concentration 

points are averaged to obtain an average 

soil concentration for each facility for 

each PB–HAP. For the water, sediment, 

and fish tissue concentrations, the 

highest value for each facility for each 

pollutant is used. If emission 

concentrations from a facility do not 

exceed the Tier 2 screening level, the 

facility passes the screen, and typically 

is not evaluated further. If emissions 

from a facility exceed the Tier 2 

screening level, the facility does not 

pass the screen and, therefore, may have 

the potential to cause adverse 

environmental effects. Such facilities 

are evaluated further to investigate 

factors such as the magnitude and 

characteristics of the area of exceedance. 

g. Acid Gas Methodology 

The environmental screening analysis 

evaluates the potential phytotoxicity 

and reduced productivity of plants due 

to chronic exposure to acid gases. The 

environmental risk screening 

methodology for acid gases is a singletier screen that compares the average 

off-site ambient air concentration over 

the modeling domain to ecological 

benchmarks for each of the acid gases. 

Because air concentrations are 

compared directly to the ecological 

benchmarks, emission-based screening 

levels are not calculated for acid gases. 

For purposes of ecological risk 

screening, the EPA identifies a potential 

for adverse environmental effects to 

plant communities from exposure to 

acid gases when the average 

concentration of the HAP around a 

facility exceeds the LOAEL ecological 

benchmark. In such cases, we further 

investigate factors such as the 

magnitude and characteristics of the 

area of exceedance (e.g., land use of 

exceedance area, size of exceedance 

area) to determine if there is an adverse 

environmental effect. 

For further information on the 

environmental screening analysis 

approach, see the Residual Risk 

Assessment for the Portland Cement 

Manufacturing Industry Source 

Category in Support of the Risk and 

Technology Review September 2017 

Proposed Rule, which is available in the 

docket for this action. 

7. How did we conduct facility-wide 

assessments? 

To put the source category risks in 

context, we typically examine 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, 

we examine the HAP emissions not only 

from the source category emission 

points of interest, but also emissions of 

HAP from all other emission sources at 

the facility for which we have data. For 

this source category, we conducted the 

facility-wide assessment using the 2014 

NEI. We analyzed risks due to the 

inhalation of HAP that are emitted 

‘‘facility-wide’’ for the populations 

residing within 50 km of each facility, 

consistent with the methods used for 

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 facilitywide risks that could be attributed to the 

source category 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 

Residual Risk Assessment for the 

Portland Cement Manufacturing 

Industry Source Category in Support of 

the Risk and Technology Review 

September 2017 Proposed Rule, 

available through the docket for this 

action, provides the methodology and 

results of the facility-wide analyses, 

including all facility-wide risks and the 

percentage of source category 

contribution to facility-wide risks. 

8. How did we consider uncertainties in 

risk assessment? 

In the Benzene NESHAP, we 

concluded that risk estimation 

uncertainty should be considered in our 

decision-making under the ample 

margin of safety framework. Uncertainty 

and the potential for bias are inherent in 

all risk assessments, including those 

performed for this proposal. Although 

uncertainty exists, we believe that our 

approach, which used conservative 

tools and assumptions, ensures that our 

decisions are health protective and 

environmentally protective. A brief 

discussion of the uncertainties in the 

RTR emissions dataset, dispersion 

modeling, inhalation exposure 

estimates, and dose-response 

relationships follows below. A more 

thorough discussion of these 

uncertainties is included in the Residual 

Risk Assessment for the Portland 

Cement Manufacturing Industry Source 

Category in Support of the Risk and 

Technology Review September 2017 

Proposed Rule, which is available in the 

docket for this action. 

a. Uncertainties in the RTR Emissions 

Dataset 

Although the development of the RTR 

emissions dataset 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 are incomplete or 

missing, the degree to which 

assumptions made to complete the 

datasets are accurate, errors in emission 

estimates, and other factors. The 

emission estimates considered in this 

analysis generally are annual totals for 

certain years, and they do not reflect 

short-term fluctuations during the 

course of a year or variations from year 

to year. The estimates of peak hourly 

emission rates for the acute effects 

screening assessment were based on an 

emission adjustment factor applied to 

the average annual hourly emission 

rates, which are intended to account for 

emission fluctuations due to normal 

facility operations. 

b. Uncertainties in Dispersion Modeling 

We recognize there is uncertainty in 

ambient concentration estimates 

associated with any model, including 

the EPA’s recommended regulatory 

dispersion model, AERMOD. In using a 

model to estimate ambient pollutant 

concentrations, the user chooses certain 

options to apply. For RTR assessments, 


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15Short-term mobility is movement from one 

micro-environment 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. 

16U.S. EPA. National-Scale Air Toxics 

Assessment for 1996. (EPA 453/R–01–003; January 

2001; page 85.) 

17 IRIS glossary (https://ofmpub.epa.gov/sor_

internet/registry/termreg/searchandretrieve/

glossariesandkeywordlists/search.do?details=

&glossaryName=IRIS%20Glossary). 

we select some model options that have 

the potential to overestimate ambient air 

concentrations (e.g., not including 

plume depletion or pollutant 

transformation). We select other model 

options that have the potential to 

underestimate ambient impacts (e.g., not 

including building downwash). Other 

options that we select have the potential 

to either under- or overestimate ambient 

levels (e.g., meteorology and receptor 

locations). On balance, considering the 

directional nature of the uncertainties 

commonly present in ambient 

concentrations estimated by dispersion 

models, the approach we apply in the 

RTR assessments should yield unbiased 

estimates of ambient HAP 

concentrations. 

c. Uncertainties in Inhalation Exposure 

The EPA did not include the effects 

of human mobility on exposures in the 

assessment. Specifically, short-term 

mobility and long-term mobility 

between census blocks in the modeling 

domain were not considered.15 The 

approach of not considering short or 

long-term population mobility does not 

bias the estimate of the theoretical MIR 

(by definition), nor does it affect the 

estimate of cancer incidence because the 

total population number remains the 

same. It does, however, affect the shape 

of the distribution of individual risks 

across the affected population, shifting 

it toward higher estimated individual 

risks at the upper end and reducing the 

number of people estimated to be at 

lower risks, thereby increasing the 

estimated number of people at specific 

high risk levels (e.g., 1-in-10 thousand 

or 1-in-1 million). 

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 

farther from the facility and underpredict 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. We reduce 

this uncertainty by analyzing large 

census blocks near facilities using aerial 

imagery and adjusting the location of 

the block centroid to better represent the 

population in the block, as well as 

adding additional receptor locations 

where the block population is not well 

represented by a single location. 

The assessment evaluates 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 emission 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 domestic 

facilities) will influence the future risks 

posed by a given source or source 

category. Depending on the 

characteristics of the industry, these 

factors will, in most cases, result in an 

overestimate both in individual risk 

levels and in the total estimated number 

of cancer cases. However, in the 

unlikely scenario where a facility 

maintains, or even increases, its 

emissions levels over a period of more 

than 70 years, residents live beyond 70 

years at the same location, and the 

residents spend most of their days at 

that location, then the cancer inhalation 

risks could potentially be 

underestimated. However, annual 

cancer incidence estimates from 

exposures to emissions from these 

sources would not be affected by the 

length of time an emissions source 

operates. 

The exposure estimates used in these 

analyses assume chronic exposures to 

ambient (outdoor) 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 of the HAP, indoor 

levels are roughly equivalent to ambient 

levels, but for very reactive pollutants or 

larger particles, indoor levels are 

typically lower. This factor has the 

potential to result in an overestimate of 

25 to 30 percent of exposures.16

In addition to the uncertainties 

highlighted above, there are several 

factors specific to the acute exposure 

assessment that the EPA conducts as 

part of the risk review under section 112 

of the CAA 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 the presence of 

humans at the location of the maximum 

concentration. In the acute screening 

assessment that we conduct under the 

RTR program, we assume that peak 

emissions from the source category and 

worst-case meteorological conditions 

co-occur, thus, resulting in maximum 

ambient concentrations. These two 

events are unlikely to occur at the same 

time, making these assumptions 

conservative. We then include the 

additional assumption that a person is 

located at this point during this same 

time period. For this source category, 

these assumptions would tend to be 

worst-case actual exposures as it is 

unlikely that a person would be located 

at the point of maximum exposure 

during the time when peak emissions 

and worst-case meteorological 

conditions occur simultaneously. 

d. Uncertainties in Dose-Response 

Relationships 

There are uncertainties inherent in 

the development of the dose-response 

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 the 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’s 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 variability in doseresponse relationships is given in the 

Residual Risk Assessment for the 

Portland Cement Manufacturing 

Industry Source Category in Support of 

the Risk and Technology Review 

September 2017 Proposed Rule, which 

is available in the docket for this action. 

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).17 In some 

circumstances, the true risk could be as 


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18An 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. 

19According 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 the 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, An 

Examination of EPA Risk Assessment Principles 

and Practices, EPA/100/B–04/001, 2004, available 

at https://nctc.fws.gov/resources/course-resources/

pesticides/Risk%20Assessment/Risk

%20Assessment%20Principles%20and

%20Practices.pdf. 

low as zero; however, in other 

circumstances, the risk could be 

greater.18 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, the 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 RfC and reference 

dose (RfD) values represent chronic 

exposure levels that are intended to be 

health-protective levels. Specifically, 

these values provide an estimate (with 

uncertainty spanning perhaps an order 

of magnitude) of a continuous 

inhalation exposure (RfC) or a daily oral 

exposure (RfD) to the human population 

(including sensitive subgroups) that is 

likely to be without an appreciable 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 

and 1994) which considers uncertainty, 

variability, and gaps in the available 

data. The UF are applied to derive 

reference values that are intended to 

protect against appreciable risk of 

deleterious effects. The UF are 

commonly default values,19 (e.g., factors 

of 10 or 3), used in the absence of 

compound-specific data; where data are 

available, a 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 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. The UF are applied based 

on chemical-specific or health effectspecific 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 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 observed 

adverse effect (exposure) level to no 

observed adverse 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 shortterm dose-response values at different 

levels of severity should be factored into 

the risk characterization as potential 

uncertainties. 

Although every effort is made to 

identify appropriate human health effect 

dose-response assessment values for all 

pollutants emitted by the sources in this 

risk assessment, some HAP emitted by 

this source category are lacking doseresponse assessments. Accordingly, 

these pollutants cannot be included in 

the quantitative risk assessment, which 

could result in quantitative estimates 

understating HAP risk. To help to 

alleviate this potential underestimate, 

where we conclude similarity with a 

HAP for which a dose-response 

assessment value is available, we use 

that value as a surrogate for the 

assessment of the HAP for which no 

value is available. To the extent use of 

surrogates indicates appreciable risk, we 

may identify a need to increase priority 

for new IRIS assessment of that 

substance. We additionally note that, 

generally speaking, HAP of greatest 

concern due to environmental 

exposures and hazard are those for 

which dose-response assessments have 

been performed, reducing the likelihood 

of understating risk. Further, HAP not 

included in the quantitative assessment 

are assessed qualitatively and 

considered in the risk characterization 

that informs the risk management 

decisions, including with regard to 

consideration of HAP reductions 

achieved by various control options. 

For a group of compounds that are 

unspeciated (e.g., glycol ethers), we 

conservatively use the most protective 

reference value of an individual 

compound in that group to estimate 

risk. Similarly, for an individual 

compound in a group (e.g., ethylene 

glycol diethyl ether) that does not have 

a specified reference value, we also 

apply the most protective reference 

value from the other compounds in the 

group to estimate risk. 

e. Uncertainties in the Multipathway 

Assessment 

For each source category, we 

generally rely on site-specific levels of 

PB–HAP emissions to determine 

whether a refined assessment of the 

impacts from multipathway exposures 

is necessary. This determination is 

based on the results of a three-tiered 

screening analysis that relies on the 

outputs from models that estimate 

environmental pollutant concentrations 

and human exposures for five PB–HAP. 

Two important types of uncertainty 


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20 In the context of this discussion, the term 

‘‘uncertainty’’ as it pertains to exposure and risk 

encompasses both variability in the range of 

expected inputs and screening results due to 

existing spatial, temporal, and other factors, as well 

as uncertainty in being able to accurately estimate 

the true result. 

21 In the context of this discussion, the term 

‘‘uncertainty,’’ as it pertains to exposure and risk 

assessment, encompasses both variability in the 

range of expected inputs and screening results due 

to existing spatial, temporal, and other factors, as 

well as uncertainty in being able to accurately 

estimate the true result. 

associated with the use of these models 

in RTR risk assessments and inherent to 

any assessment that relies on 

environmental modeling are model 

uncertainty and input uncertainty.20

Model uncertainty concerns whether 

the selected models are appropriate for 

the assessment being conducted and 

whether they adequately represent the 

actual processes that might occur for 

that situation. An example of model 

uncertainty is the question of whether 

the model adequately describes the 

movement of a pollutant through the 

soil. This type of uncertainty is difficult 

to quantify. However, based on feedback 

received from previous EPA SAB 

reviews and other reviews, we are 

confident that the models used in the 

screen are appropriate and state-of-theart for the multipathway risk 

assessments conducted in support of 

RTR. 

Input uncertainty is concerned with 

how accurately the models have been 

configured and parameterized for the 

assessment at hand. For Tier 1 of the 

multipathway screen, we configured the 

models to avoid underestimating 

exposure and risk. This was 

accomplished by selecting upper-end 

values from nationally-representative 

datasets for the more influential 

parameters in the environmental model, 

including selection and spatial 

configuration of the area of interest, lake 

location and size, meteorology, surface 

water and soil characteristics, and 

structure of the aquatic food web. We 

also assume an ingestion exposure 

scenario and values for human exposure 

factors that represent reasonable 

maximum exposures. 

In Tier 2 of the multipathway 

assessment, we refine the model inputs 

to account for meteorological patterns in 

the vicinity of the facility versus using 

upper-end national values, and we 

identify the actual location of lakes near 

the facility rather than the default lake 

location that we apply in Tier 1. By 

refining the screening approach in Tier 

2 to account for local geographical and 

meteorological data, we decrease the 

likelihood that concentrations in 

environmental media are overestimated, 

thereby increasing the usefulness of the 

screen. The assumptions and the 

associated uncertainties regarding the 

selected ingestion exposure scenario are 

the same for Tier 1 and Tier 2. 

For both Tiers 1 and 2 of the 

multipathway assessment, our approach 

to addressing model input uncertainty is 

generally cautious. We choose model 

inputs from the upper end of the range 

of possible values for the influential 

parameters used in the models, and we 

assume that the exposed individual 

exhibits ingestion behavior that would 

lead to a high total exposure. This 

approach reduces the likelihood of not 

identifying high risks for adverse 

impacts. 

Despite the uncertainties, when 

individual pollutants or facilities do 

screen out, we are confident that the 

potential for adverse multipathway 

impacts on human health is very low. 

On the other hand, when individual 

pollutants or facilities do not screen out, 

it does not mean that multipathway 

impacts are significant, only that we 

cannot rule out that possibility and that 

a refined multipathway analysis for the 

site might be necessary to obtain a more 

accurate risk characterization for the 

source category. The site-specific 

multipathway assessment improves 

upon the screens by utilizing AERMOD 

to estimate dispersion and deposition 

impacts upon delineated watersheds 

and farms. This refinement also 

provides improved soil and water runoff calculations for effected watershed(s) 

and adjacent parcels in estimating 

media concentrations for each PB–HAP 

modeled. 

For further information on 

uncertainties and the Tier 1 and 2 

screening methods, refer to Appendix 5 

of the risk report, ‘‘Technical Support 

Document for TRIM-Based 

Multipathway Tiered Screening 

Methodology for RTR: Summary of 

Approach and Evaluation.’’ 

f. Uncertainties in the Environmental 

Risk Screening Assessment 

For each source category, we 

generally rely on site-specific levels of 

environmental HAP emissions to 

perform an environmental screening 

assessment. The environmental 

screening assessment is based on the 

outputs from models that estimate 

environmental HAP concentrations. The 

TRIM.FaTE multipathway model and 

the AERMOD air dispersion model, are 

used to estimate environmental HAP 

concentrations for the environmental 

screening analysis. The human 

multipathway screening analysis are 

based upon the TRIM.FaTE model, 

while the site-specific assessments 

incorporate AERMOD model runs into 

the TRIM.FaTE model runs. Therefore, 

both screening assessments have similar 

modeling uncertainties. 

Two important types of uncertainty 

associated with the use of these models 

in RTR environmental screening 

assessments (and inherent to any 

assessment that relies on environmental 

modeling) are model uncertainty and 

input uncertainty.21

Model uncertainty concerns whether 

the selected models are appropriate for 

the assessment being conducted and 

whether they adequately represent the 

movement and accumulation of 

environmental HAP emissions in the 

environment. For example, does the 

model adequately describe the 

movement of a pollutant through the 

soil? This type of uncertainty is difficult 

to quantify. However, based on feedback 

received from previous EPA SAB 

reviews and other reviews, we are 

confident that the models used in the 

screen are appropriate and state-of-theart for the environmental risk 

assessments conducted in support of 

our RTR analyses. 

Input uncertainty is concerned with 

how accurately the models have been 

configured and parameterized for the 

assessment at hand. For Tier 1 of the 

environmental screen for PB–HAP, we 

configured the models to avoid 

underestimating exposure and risk to 

reduce the likelihood that the results 

indicate the risks are lower than they 

actually are. This was accomplished by 

selecting upper-end values from 

nationally-representative datasets for 

the more influential parameters in the 

environmental model, including 

selection and spatial configuration of 

the area of interest, the location and size 

of any bodies of water, meteorology, 

surface water and soil characteristics, 

and structure of the aquatic food web. 

In Tier 1, we used the maximum 

facility-specific emissions for the PB– 

HAP (other than lead compounds, 

which were evaluated by comparison to 

the Secondary Lead NAAQS) that were 

included in the environmental 

screening assessment and each of the 

media when comparing to ecological 

benchmarks. This is consistent with the 

conservative design of Tier 1 of the 

screen. In Tier 2 of the environmental 

screening analysis for PB–HAP, we 

refine the model inputs to account for 

meteorological patterns in the vicinity 

of the facility versus using upper-end 

national values, and we identify the 

locations of water bodies near the 

facility location. By refining the 


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22Although 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. 

screening approach in Tier 2 to account 

for local geographical and 

meteorological data, we decrease the 

likelihood that concentrations in 

environmental media are overestimated, 

thereby increasing the usefulness of the 

screen. To better represent widespread 

impacts, the modeled soil 

concentrations are averaged in Tier 2 to 

obtain one average soil concentration 

value for each facility and for each PB– 

HAP. For PB–HAP concentrations in 

water, sediment, and fish tissue, the 

highest value for each facility for each 

pollutant is used. 

For the environmental screening 

assessment for acid gases, we employ a 

single-tiered approach. We use the 

modeled air concentrations and 

compare those with ecological 

benchmarks. 

For both Tiers 1 and 2 of the 

environmental screening assessment, 

our approach to addressing model input 

uncertainty is generally cautious. We 

choose model inputs from the upper 

end of the range of possible values for 

the influential parameters used in the 

models, and we assume that the 

exposed individual exhibits ingestion 

behavior that would lead to a high total 

exposure. This approach reduces the 

likelihood of not identifying potential 

risks for adverse environmental impacts. 

Uncertainty also exists in the 

ecological benchmarks for the 

environmental risk screening analysis. 

We established a hierarchy of preferred 

benchmark sources to allow selection of 

benchmarks for each environmental 

HAP at each ecological assessment 

endpoint. In general, EPA benchmarks 

used at a programmatic level (e.g., 

Office of Water, Superfund Program) 

were used if available. If not, we used 

EPA benchmarks used in regional 

programs (e.g., Superfund Program). If 

benchmarks were not available at a 

programmatic or regional level, we used 

benchmarks developed by other 

agencies (e.g., NOAA) or by state 

agencies. 

In all cases (except for lead 

compounds, which were evaluated 

through a comparison to the NAAQS), 

we searched for benchmarks at the 

following three effect levels, as 

described in section III.A.6 of this 

preamble: 

1. A no-effect level (i.e., NOAEL). 

2. Threshold-effect level (i.e., 

LOAEL). 

3. Probable effect level (i.e., PEL). 

For some ecological assessment 

endpoint/environmental HAP 

combinations, we could identify 

benchmarks for all three effect levels, 

but for most, we could not. In one case, 

where different agencies derived 

significantly different numbers to 

represent a threshold for effect, we 

included both. In several cases, only a 

single benchmark was available. In 

cases where multiple effect levels were 

available for a particular PB–HAP and 

assessment endpoint, we used all of the 

available effect levels to help us to 

determine whether risk exists and if the 

risks could be considered significant 

and widespread. 

The EPA evaluates the following eight 

HAP in the environmental risk 

screening assessment: cadmium 

compounds, D/F, arsenic compounds, 

POM, mercury compounds (both 

inorganic mercury and methyl mercury), 

lead compounds, HCl, and HF, where 

applicable. These eight HAP represent 

pollutants that can cause adverse 

impacts for plants and animals either 

through direct exposure to HAP in the 

air or through exposure to HAP that is 

deposited from the air onto soils and 

surface waters. These eight HAP also 

represent those HAP for which we can 

conduct a meaningful environmental 

risk screening assessment. For other 

HAP not included in our screening 

assessment, the model has not been 

parameterized such that it can be used 

for that purpose. In some cases, 

depending on the HAP, we may not 

have appropriate multipathway models 

that allow us to predict the 

concentration of that pollutant. The EPA 

acknowledges that other HAP beyond 

the eight HAP that we are evaluating 

may have the potential to cause adverse 

environmental effects and, therefore, the 

EPA may evaluate other relevant HAP in 

the future, as modeling science and 

resources allow. 

Further information on uncertainties 

and the Tier 1 and 2 environmental 

screening methods is provided in 

Appendix 5 of the document, Technical 

Support Document for TRIM-Based 

Multipathway Tiered Screening 

Methodology for RTR: Summary of 

Approach and Evaluation. Also, see the 

Residual Risk Assessment for Portland 

Cement Manufacturing Industry Source 

Category in Support of the Risk and 

Technology Review September 2017 

Proposed Rule, available in the docket 

for this action. 

B. How did we consider the risk results 

in making decisions for this proposal? 

As discussed in section II.A of this 

preamble, in evaluating and developing 

standards under CAA section 112(f)(2), 

we apply a two-step process to address 

residual risk. In the first step, the EPA 

determines whether 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) 22 of approximately 

[1-in-10 thousand] [i.e., 100-in-1 

million].’’ 54 FR 38045, September 14, 

1989. If risks are unacceptable, the EPA 

must determine the emission standards 

necessary to bring risks to an acceptable 

level without considering costs. In the 

second step of the process, the EPA 

considers whether the emissions 

standards provide 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. The EPA 

must promulgate emission standards 

necessary to provide an ample margin of 

safety. After conducting the ample 

margin of safety analysis, we consider 

whether a more stringent standard is 

necessary to prevent, taking into 

consideration, costs, energy, safety, and 

other relevant factors, an adverse 

environmental effect. 

In past residual risk actions, the EPA 

considered a number of human health 

risk metrics associated with emissions 

from the categories under review, 

including the MIR, the number of 

persons in various risk ranges, cancer 

incidence, the maximum non-cancer HI 

and the maximum acute non-cancer 

hazard. See, e.g., 72 FR 25138, May 3, 

2007; and 71 FR 42724, July 27, 2006. 

The EPA considered this health 

information for both actual and 

allowable emissions. See, e.g., 75 FR 

65068, October 21, 2010; 75 FR 80220, 

December 21, 2010; 76 FR 29032, May 

19, 2011. The EPA also discussed risk 

estimation uncertainties and considered 

the uncertainties in the determination of 

acceptable risk and ample margin of 

safety in these past actions. The EPA 

considered this same type of 

information in support of this action. 

The Agency is considering these 

various measures of health information 

to inform our determinations of risk 

acceptability and ample margin of safety 

under CAA section 112(f). As explained 

in the Benzene NESHAP, ‘‘the first step 

judgment on acceptability cannot be 

reduced to any single factor’’ and, thus, 

‘‘[t]he Administrator believes that the 

acceptability of risk under [previous] 

section 112 is best judged on the basis 

of a broad set of health risk measures 

and information.’’ 54 FR 38046, 

September 14, 1989. Similarly, with 


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23The 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/ 

4AB3966E263D943A8525771F00668381/$File/EPASAB-10-007-unsigned.pdf) are outlined in a 

memorandum to this rulemaking docket from David 

Guinnup titled, EPA’s Actions in Response to the 

Key Recommendations of the SAB Review of RTR 

Risk Assessment Methodologies. 

regard to the ample margin of safety 

determination, ‘‘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.’’ Id. 

The Benzene NESHAP approach 

provides flexibility regarding factors the 

EPA may consider in making 

determinations and how the EPA may 

weigh those factors for each source 

category. In responding to comment on 

our policy under the Benzene NESHAP, 

the EPA explained that: 

[t]he 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’. 

See 54 FR at 38057, September 14, 

1989. Thus, the level of the MIR is only 

one factor to be weighed in determining 

acceptability of risks. The Benzene 

NESHAP explained that ‘‘an MIR of 

approximately one 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 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.’’ Id. at 38045. 

Similarly, with regard to the ample 

margin of safety analysis, the EPA stated 

in the Benzene NESHAP 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.’’ Id. at 38061. We also 

consider the uncertainties associated 

with the various risk analyses, as 

discussed earlier in this preamble, in 

our determinations of acceptability and 

ample margin of safety. 

The EPA notes that it has not 

considered certain health information to 

date in making residual risk 

determinations. At this time, we do not 

attempt to quantify those HAP risks that 

may be associated with emissions from 

other facilities that do not include the 

source categories in question, mobile 

source emissions, natural source 

emissions, persistent environmental 

pollution, or atmospheric 

transformation in the vicinity of the 

sources in these categories. 

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. We recognize that such 

consideration may be particularly 

important when assessing non-cancer 

risks, where pollutant-specific exposure 

health reference levels (e.g., RfCs) 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 SAB advised the EPA 

‘‘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.’’ 23

In response to the SAB 

recommendations, the EPA is 

incorporating cumulative risk analyses 

into its RTR risk assessments, including 

those reflected in this proposal. The 

Agency is: (1) Conducting facility-wide 

assessments, which include source 

category emission points, as well as 

other emission points within the 

facilities; (2) considering sources in the 

same category whose emissions result in 

exposures to the same individuals; and 

(3) for some persistent and 

bioaccumulative pollutants, analyzing 

the ingestion route of exposure. In 

addition, the RTR risk assessments have 

always considered aggregate cancer risk 

from all carcinogens and aggregate noncancer HI from all non-carcinogens 

affecting the same target organ system. 

Although 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 

concerned about the uncertainties of 

doing so. Because of the contribution to 

total HAP risk from emission sources 

other than those that we have studied in 

depth during this RTR review, such 

estimates of total HAP risks would have 

significantly greater associated 

uncertainties than the source category or 

facility-wide estimates. Such aggregate 

or cumulative assessments would 

compound those uncertainties, making 

the assessments too unreliable. 

C. How did we perform the technology 

review? 

Our technology review focused on the 

identification and evaluation of 

developments in practices, processes, 

and control technologies that have 

occurred since the MACT standards 

were promulgated. Where we identified 

such developments, in order to inform 

our decision of whether it is 

‘‘necessary’’ to revise the emissions 

standards, we analyzed the technical 

feasibility of applying these 

developments and the estimated costs, 

energy implications, non-air 

environmental impacts, as well as 

considering the emission reductions. 

We also considered the appropriateness 

of applying controls to new sources 

versus retrofitting existing sources. 

Based on our analyses of the available 

data and information, we identified 

potential developments in practices, 

processes, and control technologies. For 

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 development of 

the original MACT standards; 

• Any improvements in add-on 

control technology or other equipment 

(that were identified and considered 

during development of the original 


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24Burger, J. 2002. Daily Consumption of Wild 

Fish and Game: Exposures of High End 

Recreationists. International Journal of 

Environmental Health Research, 12:343–354. 

25U.S. EPA. Exposure Factors Handbook, 2011 

Edition (Final). U.S. Environmental Protection 

Agency, Washington, DC, EPA/600/R–09/052F, 

2011. 

MACT standards) that could result in 

additional emissions reduction; 

• Any work practice or operational 

procedure that was not identified or 

considered during development of the 

original MACT standards; 

• Any process change or pollution 

prevention alternative that could be 

broadly applied to the industry and that 

was not identified or considered during 

development of the original MACT 

standards; and 

• Any significant changes in the cost 

(including cost effectiveness) of 

applying controls (including controls 

the EPA considered during the 

development of the original MACT 

standards). 

In addition to reviewing the practices, 

processes, and control technologies that 

were considered at the time we 

originally developed (or last updated) 

the NESHAP, we reviewed a variety of 

data sources in our investigation of 

potential practices, processes, or 

controls to consider. Among the sources 

we reviewed were the NESHAP for 

various industries that were 

promulgated since the MACT standards 

being reviewed in this action. We 

reviewed the regulatory requirements 

and/or technical analyses associated 

with these regulatory actions to identify 

any practices, processes, and control 

technologies considered in these efforts 

that could be applied to emission 

sources in the Portland Cement 

Manufacturing Industry source category, 

as well as the costs, non-air impacts, 

and energy implications associated with 

the use of these technologies. Finally, 

we reviewed information from other 

sources, such as state and/or local 

permitting agency databases and 

industry-supported databases. 

IV. Analytical Results and Proposed 

Decisions 

A. What are the results of the risk 

assessment and analyses? 

1. Inhalation Risk Assessment Results 

Table 3 of this preamble provides an 

overall summary of the inhalation risk 

results. The results of the chronic 

baseline inhalation cancer risk 

assessment indicate that, based on 

estimates of current actual and 

allowable emissions, the MIR posed by 

the Portland Cement Manufacturing 

Industry source category was estimated 

to be 1-in-1 million and 4-in-1 million, 

respectively, from volatile HAP being 

emitted from the kilns. The total 

estimated cancer incidence from 

Portland Cement Manufacturing 

Industry emission sources based on 

actual emission levels is 0.01 excess 

cancer cases per year, or one case in 

every 100 years. The total estimated 

cancer incidence from Portland Cement 

Manufacturing Industry emission 

sources based on allowable emission 

levels is 0.03 excess cancer cases per 

year, or one case in every 33 years. 

Emissions of formaldehyde, benzene, 

naphthalene, and acetaldehyde 

contributed 91 percent to this cancer 

incidence. The population exposed to 

cancer risks greater than or equal to 1- 

in-1 million considering actual 

emissions was estimated to be 

approximately 130; for allowable 

emissions, approximately 2,300 people 

were estimated to be exposed to cancer 

risks greater than or equal to 1-in-1 

million. 

TABLE 3—INHALATION RISK ASSESSMENT SUMMARY FOR PORTLAND CEMENT MANUFACTURING INDUSTRY SOURCE

CATEGORY

Cancer MIR 

(in-1 million) Cancer 

incidence 

(cases per 

year) 1

Population 

with risk of 

1-in-1 million 

or greater 1

Population 

with risk of 

10-in-1 million 

or greater 1

Max chronic 

noncancer HI Based on actual 

emissions 

Based on allowable 

emissions 

Source Category ...... 1 (formaldehyde, 

benzene).

4 (formaldehyde, 

benzene).

0.01 130 0 HI < 1 (Actuals and 

Allowables). 

Whole Facility ........... 70 (arsenic and chromium VI)................................... 0.02 20,000 690 HI = 1 (Actuals). 

1 Cancer incidence and populations exposed are based upon actual emissions. 

The maximum chronic noncancer HI 

(TOSHI) values for the source category, 

based on actual and allowable 

emissions, were estimated to be 0.02 

and 0.06, respectively, with 

formaldehyde, acetaldehyde, and 

hydrochloric acid driving the TOSHI 

value. 

2. Acute Risk Results 

Worst-case acute HQs were calculated 

for every HAP for which there is an 

acute health benchmark using actual 

emissions. The maximum acute 

noncancer HQ value for the source 

category was less than 1. Acute HQs are 

based upon actual emissions. 

3. Multipathway Risk Screening Results 

Results of the worst-case Tier 1 

screening analysis indicate that PB– 

HAP emissions (based on estimates of 

actual emissions) from 70 of the 91 

facilities in the source category exceed 

the screening values for the 

carcinogenic PB–HAP (D/F and arsenic) 

and that PB–HAP emissions from 68 of 

the 91 facilities exceed the screening 

values for mercury, a noncarcinogenic 

PB–HAP. Cadmium emissions were 

below the Tier 1 emission noncancer 

screening level for each facility based 

upon the combined Farmer and Fisher 

scenarios. For the PB–HAP and facilities 

that did not screen out at Tier 1, we 

conducted a Tier 2 screening analysis. 

The Tier 2 screen replaces some of the 

assumptions used in Tier 1 with sitespecific data, the location of fishable 

lakes, and local wind direction and 

speed. The Tier 2 screen continues to 

rely on high-end assumptions about 

consumption of local fish and locally 

grown or raised foods (adult female 

angler at 99th percentile consumption 

for fish 24 for the Fisher Scenario and 

90th percentile for consumption of 

locally grown or raised foods 25) for the 

Farmer Scenario and uses an 

assumption that the same individual 

consumes each of these foods in high 

end quantities (i.e., that an individual 

has high end ingestion rates for each 

food). The result of this analysis was the 

development of site-specific 

concentrations of D/F, arsenic 

compounds, and mercury compounds. It 

is important to note that, even with the 

inclusion of some site-specific 

information in the Tier 2 analysis, the 

multipathway screening analysis is still 


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a very conservative, health-protective 

assessment (e.g., upper-bound 

consumption of local fish, locally 

grown, and/or raised foods) and in all 

likelihood will yield results that serve 

as an upper-bound multipathway risk 

associated with a facility. 

Based on the Tier 2 screening 

analysis, 45 facilities emit D/F and 

arsenic that exceed the Tier 2 cancer 

screening value. D/F emissions 

exceeded the screening value by a factor 

of as much as 100 for the fisher scenario 

and by as much as 30 for the farmer 

scenario. For arsenic, the facility with 

the largest exceedance of the cancer 

screening value had an exceedance of 10 

times the Tier 1 emission rate level 

resulting in a Tier 2 screening value less 

than 1 for both the Fisher and Farmer 

scenarios. For mercury, 24 facilities 

emit mercury emissions above the 

noncancer screening value, with at least 

one facility exceeding the screening 

value by a factor of 30 for the Fisher 

scenario. When we considered the effect 

multiple facilities within the source 

category could have on common lake(s) 

in the modeling domain, mercury 

emissions exceeded the noncancer 

screening value by a factor of 40. 

For D/F, we conducted a Tier 3 

multipathway screen for the facility 

with the highest Tier 2 multipathway 

cancer screen (a value of 100) for the 

Fisher scenario. The next highest 

facility had a Tier 2 cancer screen value 

of 40. Tier 3 has three individual stages, 

and we progressed through each of 

those stages until either the facility’s 

PB–HAP emissions did not exceed the 

screening value or all three stages had 

been completed. These stages included 

lake, plume rise, and time-series 

assessments. Based on this Tier 3 

screening analysis, the MIR facility had 

D/F emissions that exceeded the 

screening value by a factor of 20 for the 

Fisher scenario. Further details on the 

Tier 3 screening analysis can be found 

in Appendix 11 of Residual Risk 

Assessment for the Portland Cement 

Manufacturing Industry Source 

Category in Support of the Risk and 

Technology Review September 2017 

Proposed Rule.’’ 

An exceedance of a screening value in 

any of the tiers cannot be equated with 

a risk value or a HQ (or HI). Rather, it 

represents a high-end estimate of what 

the risk or hazard may be. For example, 

facility emissions exceeding the 

screening value by a factor of 2 for a 

non-carcinogen can be interpreted to 

mean that we are confident that the HQ 

would be lower than 2. Similarly, 

facility emissions exceeding the 

screening value by a factor of 20 for a 

carcinogen means that we are confident 

that the risk is lower than 20-in-1 

million. Our confidence comes from the 

health-protective assumptions that are 

in the screens: we choose inputs from 

the upper end of the range of possible 

values for the influential parameters 

used in the screens; and we assume that 

the exposed individual exhibits 

ingestion behavior that would lead to a 

high total exposure. 

For mercury emissions, we conducted 

a site-specific assessment. Analysis of 

the facilities with the highest Tier 2 

screen values helped identify the 

location for the site-specific assessment 

and the facilitie(s) to model with TRIM_

FaTE. We also considered the effect 

multiple facilities within the source 

category could have on common lake(s) 

in the modeling domain. The selection 

of the facility(s) for the site-specific 

assessment also included evaluating the 

number and location of lakes impacted, 

watershed boundaries, and land-use 

features around the target lakes, (i.e., 

elevation changes, topography, rivers). 

The three facilities selected are 

located in Midlothian, Texas. One of the 

three facilities had the largest Tier 2 

screen value, as well as the lake with 

the highest aggregated noncancer screen 

value for mercury with a lake size of 

over 6,600 acres. These sites were 

selected because of the Tier 2 mercury 

screening results and based on the 

feasibility, with respect to the modeling 

framework, of obtaining parameter 

values for the region surrounding the 

facilities. We expect that the exposure 

scenarios we assessed are among the 

highest that might be encountered for 

other facilities in this source category. 

The refined site-specific 

multipathway assessment, as in the 

screening assessments, includes some 

hypothetical elements, namely the 

hypothetical human receptor (e.g., the 

Fisher scenario which did not screen 

out in the screening assessments). We 

also included children in different age 

ranges and adults with lifetime cancer 

risks evaluated for carcinogens if they 

did not pass the screening, and 

noncancer hazards evaluated for 

different age groups for other chemicals 

that did not pass the screening. It is 

important to note that even though the 

multipathway assessment has been 

conducted, no data exist to verify the 

existence of the hypothetical human 

receptor. 

The Fisher scenario involves an 

individual who regularly consumes fish 

caught in freshwater lakes in the 

vicinity of the source of interest over the 

course of a 70-year lifetime. Since the 

Fisher scenario did not pass the 

screening, we evaluated risks and/or 

hazards from the one lake that was 

fished in the screening assessment, with 

the same adjustments to fish ingestion 

rates as used in the screening according 

to lake acreage and its assumed impact 

on fish productivity. The refined 

multipathway assessment produced an 

HQ of 0.6 for mercury for the three 

facilities assessed. This risk assessment 

represents the maximum hazard for 

mercury through fish consumption for 

the source category and, with an HQ 

less than 1, is below the level of concern 

for exposure to emissions from these 

sources. 

In evaluating the potential for 

multipathway effects from emissions of 

lead, we compared modeled hourly lead 

concentrations to the secondary NAAQS 

for lead (0.15 mg/m3). The highest 

hourly lead concentration, of 0.023 mg/ 

m3, is below the NAAQS for lead, 

indicating a low potential for 

multipathway impacts of concern due to 

lead. 

4. Environmental Risk Screening Results 

As described in section III.A of this 

preamble, we conducted an 

environmental risk screening 

assessment for the Portland Cement 

Manufacturing Industry source category 

for the following six pollutants: Mercury 

(methyl mercury and mercuric 

chloride), arsenic, cadmium, lead, D/F, 

and HCl. In the Tier 1 screening analysis 

for PB–HAP (other than lead, which was 

evaluated differently), cadmium and 

arsenic emissions had no exceedances 

of any ecological benchmarks evaluated. 

D/F and methyl mercury emissions had 

Tier 1 exceedances for surface soil. 

Divalent mercury emissions had Tier 1 

exceedances for sediment and surface 

soil. A Tier 2 screening analysis was 

performed for D/F, divalent mercury, 

and methyl mercury emissions. In the 

Tier 2 screening analysis, D/F emissions 

had no exceedances of any ecological 

benchmarks evaluated. Divalent 

mercury emissions from six facilities 

exceeded the Tier 2 screen for a 

threshold level sediment benchmark by 

a maximum screening value of 2. The 

divalent mercury probable-effects 

benchmark for sediment was not 

exceeded. Methyl mercury emissions 

from two facilities exceeded the Tier 2 

screen for a NOAEL surface soil 

benchmark for avian ground 

insectivores (woodcock) by a maximum 

screening value of 2. Other surface soil 

benchmarks for methyl mercury were 

not exceeded. Given the low Tier 2 

maximum screening values of 2 for 

divalent mercury and methyl mercury, 

and the fact that only the most 

protective benchmarks were exceeded, a 

Tier 3 environmental risk screen was 

not conducted for this source category. 


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For lead, we did not estimate any 

exceedances of the secondary lead 

NAAQS. For HCl, the average modeled 

concentration around each facility (i.e., 

the average concentration of all off-site 

data points in the modeling domain) did 

not exceed any ecological benchmark. In 

addition, each individual modeled 

concentration of HCl (i.e., each off-site 

data point in the modeling domain) was 

below the ecological benchmarks for all 

facilities. Based on the results of the 

environmental risk screening analysis, 

we do not expect an adverse 

environmental effect as a result of HAP 

emissions from this source category. 

5. Facility-Wide Risk Results 

Results of the assessment of facilitywide emissions indicate that, of the 91 

facilities, 16 facilities have a facilitywide cancer risk greater than or equal to 

1-in-1 million (refer to Table 3). The 

maximum facility-wide cancer risk is 

70-in-1 million, mainly driven by 

arsenic and chromium (VI) emissions 

from construction activities involving 

the hauling of sand and gravel from the 

stone quarrying process. The next 

highest facility-wide cancer risk is 8-in1 million. 

The total estimated cancer incidence 

from the whole facility is 0.02 excess 

cancer cases per year, or one case in 

every 50 years. Approximately 20,000 

people are estimated to have cancer 

risks greater than or equal to 1-in-1 

million from exposure to whole facility 

emissions from 16 facilities in the 

source category. Approximately 700 

people are estimated to have cancer risk 

greater than 10-in-1 million from 

exposure to whole facility emissions 

from one facility in the source category. 

The maximum facility-wide chronic 

non-cancer TOSHI is estimated to be 

equal to 1, mainly driven by emissions 

of HCl from a drying operation routed 

through the long kiln. 

6. What demographic groups might 

benefit from this regulation? 

To examine the potential for any 

environmental justice issues that might 

be associated with the source category, 

we performed a demographic analysis of 

the population close to the facilities. In 

this analysis, we evaluated the 

distribution of HAP-related cancer and 

non-cancer risks from the Portland 

Cement Manufacturing Industry source 

category across different demographic 

groups within the populations living 

near facilities identified as having the 

highest risks. The methodology and the 

results of the demographic analyses are 

included in a technical report, Risk and 

Technology Review—Analysis of 

Demographic Factors for Populations 

Living Near Portland Cement 

Manufacturing Facilities, available in 

the docket for this action. 

The results of the demographic 

analysis are summarized in Table 4 

below. These results, for various 

demographic groups, are based on the 

estimated risks from actual emission 

levels for the population living within 

50 km of the facilities. 

TABLE 4—PORTLAND CEMENT MANUFACTURING INDUSTRY SOURCE CATEGORY DEMOGRAPHIC RISK ANALYSIS RESULTS

Nationwide 

Population with 

cancer risk at or 

above 1-in-1 

million due to 

Portland Cement 

Manufacturing 

Population with 

chronic hazard 

index above 1 due 

to Portland 

Cement 

Manufacturing 

Total Population ......................................................................................................... 317,746,049 134 0 

Race by Percent 

White .......................................................................................................................... 62 71 0 

All Other Races ......................................................................................................... 38 29 0

Race by Percent 

White .......................................................................................................................... 62 94 0 

African American ....................................................................................................... 12 1 0 

Native American ........................................................................................................ 0.8 1.6 0 

Other and Multiracial ................................................................................................. 7 3 0 

Ethnicity by Percent 

Hispanic ..................................................................................................................... 18 24 0 

Non-Hispanic ............................................................................................................. 82 76 0 

Income by Percent 

Below Poverty Level .................................................................................................. 14 10 0 

Above Poverty Level .................................................................................................. 86 90 0 

Education by Percent 

Over 25 and without High School Diploma ............................................................... 14 11 0 

Over 25 and with a High School Diploma ................................................................. 86 89 0 

The results of the Portland Cement 

Manufacturing Industry source category 

demographic analysis indicate that 

emissions from the source category 

expose approximately 130 people to a 

cancer risk at or above 1-in-1 million 

and no people to a chronic noncancer 

TOSHI greater than 1. The percentages 

of the at-risk population in each 

demographic group (except for White, 

Native American, and Hispanic) are 

similar to or lower than their respective 

nationwide percentages. The specific 

demographic results indicate that the 

percentage of the population potentially 

impacted by Portland cement emissions 

is greater than its corresponding 

nationwide percentage for the following 


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26Although 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. 

demographics: Native American (1.6 

percent compared to 0.8 percent 

nationally), Hispanic or Latino (24 

percent compared to 18 percent 

nationally) and children aged 0 to 17 (32 

percent compared to 23 percent 

nationally). The other demographic 

groups within the exposed population 

were the same or lower than the 

corresponding nationwide percentages. 

B. What are our proposed decisions 

regarding risk acceptability, ample 

margin of safety, and adverse 

environmental effects? 

1. Risk Acceptability 

As noted in section II.A.1 of this 

preamble, the EPA sets standards under 

CAA section 112(f)(2) using ‘‘a two-step 

standard-setting approach, with an 

analytical first step to determine an 

‘acceptable risk’ that considers all 

health information, including risk 

estimation uncertainty, and includes a 

presumptive limit on maximum 

individual lifetime [cancer] risk (MIR) 26

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

100-in-1 million].’’ 54 FR 38045, 

September 14, 1989. In this proposal, 

we estimated risks based on actual and 

allowable emissions. As discussed 

earlier, we consider our analysis of risk 

from allowable emissions to be 

conservative and, as such, to represent 

an upper bound estimate of inhalation 

risk from emissions allowed under the 

NESHAP for the source category. 

The inhalation cancer risk to the 

individual most exposed to emissions 

from sources in the Portland Cement 

Manufacturing Industry source category 

is 1-in-1 million based on actual 

emissions. The estimated incidence of 

cancer due to inhalation exposure is 

0.01 excess cancer cases per year, or one 

case in every 100 years, based on actual 

emissions. Approximately 130 people 

are exposed to actual emissions 

resulting in an increased cancer risk 

greater than or equal to 1-in-1 million. 

We estimate that, for allowable 

emissions, the inhalation cancer risk to 

the individual most exposed to 

emissions from sources in this source 

category is up to 4-in-1 million. The 

estimated incidence of cancer due to 

inhalation exposure is 0.02 excess 

cancer cases per year, or one case in 

every 50 years, based on allowable 

emissions. Based on allowable 

emissions, approximately 20,000 people 

could be exposed to emissions resulting 

in an increased cancer risk of up to 1- 

in-1 million, and about 690 people to an 

increased cancer risk of up to 10-in-1 

million. 

The Agency estimates that the 

maximum chronic noncancer TOSHI 

from inhalation exposure is less than 1 

due to actual emissions, and up to 1 due 

to allowable emissions. The screening 

assessment of worst-case acute 

inhalation impacts from worst-case 1- 

hour emissions indicates that no HAP 

exceed an HQ value of 1. 

Based on the results of the 

multipathway cancer screening analyses 

of arsenic and dioxin emissions, we 

conclude that the cancer risk from 

ingestion exposure to the individual 

most exposed is less than 1-in-1 million 

for arsenic and, based on a Tier 3 

analysis, less than 20-in-1 million for 

dioxins. Based on the Tier 1 

multipathway screening analysis of 

cadmium emissions and the refined sitespecific multipathway analysis of 

mercury emissions, the maximum 

chronic noncancer TOSHI due to 

inhalation exposures is less than 1 for 

actual emissions. 

In determining whether risk is 

acceptable, the EPA considered all 

available health information and risk 

estimation uncertainty, as described 

above. The results indicate that both the 

actual and allowable inhalation cancer 

risks to the individual most exposed are 

significantly less than 100-in-1 million, 

which is the presumptive limit of 

acceptability. The maximum chronic 

noncancer TOSHI due to inhalation 

exposures is less than 1 due to actual 

emissions and up to 1 due to allowable 

emissions, and our refined 

multipathway analysis indicates that 

noncancer ingestion risks also are less 

than 1. Finally, the evaluation of acute 

noncancer risks was very conservative 

and showed that acute risks are below 

a level of concern. 

Taking into account this information, 

we propose that the risk remaining after 

implementation of the existing MACT 

standards for the Portland Cement 

Manufacturing Industry is acceptable. 

2. Ample Margin of Safety Analysis 

Although we are proposing that the 

risks from the Portland Cement 

Manufacturing Industry source category 

are acceptable, for allowable emissions, 

the inhalation cancer risk to the 

individual most exposed to emissions 

from sources in this source category is 

up to 4-in-1 million, with approximately 

2,000 individuals estimated to be 

exposed to emissions resulting in an 

increased cancer risk of 1-in-1 million 

or greater. In addition, based on the Tier 

3 multipathway screening analysis, 

dioxin emissions from the MIR facility 

could pose a risk of up to 20-in-1 

million. Thus, we considered whether 

the existing MACT standards provide an 

ample margin of safety to protect public 

health. In addition to considering all of 

the health risks and other health 

information considered in the risk 

acceptability determination, in the 

ample margin of safety analysis, we 

evaluated the cost and feasibility of 

available control technologies and other 

measures (including the controls, 

measures, and costs reviewed under the 

technology review) that could be 

applied in this source category to 

further reduce the risks due to 

emissions of HAP. 

Our inhalation risk analysis indicates 

very low potential for risk from the 

facilities in the source category based 

upon actual emissions at 1-in-1 million, 

and just slightly higher risks based upon 

allowable emissions at 4-in-1 million. 

Therefore, very little reduction in 

inhalation risks could be realized 

regardless of the availability of control 

options. As directed by CAA section 

112(f)(2), we conducted an analysis to 

determine if the standard provides an 

ample margin of safety to protect public 

health. The HAP risk drivers 

contributing to the inhalation MIR in 

excess of 1-in-1 million for 40 CFR part 

63, subpart LLL facilities include 

primarily the gaseous organic HAP: 

Formaldehyde, benzene, naphthalene, 

and acetaldehyde. More than 62 percent 

of the mass emissions of these 

compounds originate from kiln 

operations. 

The following paragraphs provide our 

analyses of HAP-reducing measures that 

we considered in our ample margin of 

safety analysis. For each option, we 

considered feasibility, costeffectiveness, and health information in 

determining whether to revise standards 

in order to provide an ample margin of 

safety. 

The first technology we evaluated in 

our ample margin of safety analysis is a 

regenerative thermal oxidizer (RTO). To 

assess the costs associated with RTOs, 

we relied on our beyond-the-floor (BTF) 

analysis documented in the May 6, 

2009, Portland Cement NESHAP 

proposal (74 FR 21136). In that 

proposal, we assessed the potential for 

further reductions in THC and organic 

HAP emissions beyond the reductions 

achieved by activated carbon injection 

(ACI) (controlling mercury and THC 

emissions), the typical kiln controls 

used in the industry. To achieve further 

reductions in THC, a kiln would likely 

require additional controls, such as 

RTO. It was expected that RTO would 

only offer an additional 50-percent 

removal efficiency, due to the reduced 


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THC concentration leaving the ACI 

control device and entering the 

proposed RTO. The analysis indicates 

that addition of an RTO would reduce 

THC emissions by approximately 9 tpy, 

for a cost effectiveness of $411,000/ton. 

The HAP fraction would be 

approximately 24 percent of THC, so 2 

tpy of organic HAP would be removed, 

at a cost effectiveness of $1.7 million/ 

ton of organic HAP. The details of this 

analysis are included in 74 FR 21152– 

21153. Overall, we do not consider the 

use of an RTO to be cost effective for 

this industry, and given the small 

reduction in organic HAP emissions, the 

addition of an RTO would have little 

effect on the source category risks. 

Exposure to dioxin emissions from 

the MIR facility were found to pose a 

non-inhalation MIR of less than 20-in-1 

million, and possibly greater than 1-in1 million. Technologies evaluated 

included the use of ACI with wet 

scrubbers to help control D/F emissions. 

For the March 24, 1998, proposal (63 FR 

14182), we performed a BTF analysis 

that considered the MACT floor for D/ 

F emissions controls to be a reduction 

of the kiln exhaust gas stream 

temperature at the PM control device 

inlet to 400 degrees Fahrenheit (63 FR 

14200). An ACI system was considered 

as a potential BTF option. Total annual 

costs were estimated to be $426,000 to 

$3.3 million per kiln. The Agency 

determined that, based on the additional 

costs and the level of D/F emissions 

reduction achievable, the BTF costs 

were not justified (63 FR 14199–14201). 

We do not consider the use of ACI 

system to be cost effective for the 

industry to use to reduce D/F emissions, 

and would have little effect on the 

source category risks. 

Our multipathway screening analysis 

results did not necessarily indicate any 

risks from mercury emissions, but we 

have also performed an evaluation of 

mercury emissions controls. In the May 

6, 2009, BTF analysis, it was estimated 

for a typical 1.2 million tpy kiln, the 

addition of a halogenated carbon 

injection system would result in a 3.0 

lb/year reduction in mercury at a cost of 

$1.25 million/year and a cost 

effectiveness of $420,000/lb of mercury 

removed. If the halogenated carbon 

injection system effectiveness is 

reduced due to a low level of mercury 

entering the system, 2.3 lb/year of 

mercury would be removed at a cost 

effectiveness of $540,000/lb of mercury 

removed (74 FR 21149). We do not 

consider the use of halogenated carbon 

injection system to be cost effective for 

the industry to use to reduce mercury 

emissions, and would have little effect 

on the low risks identified for this 

source category. 

The cost-effectiveness values for 

further reduction of organic HAP, as 

referenced herein, are significantly 

higher than values in other NESHAP we 

have historically rejected for not being 

cost effective for organic HAP. As 

examples of determinations made 

historically, refer to the National 

Emission Standards for Hazardous Air 

Pollutants Residual Risk and 

Technology Review for Flexible 

Polyurethane Foam Production (August 

15, 2014, 79 FR 48078), the National 

Emission Standards for Hazardous Air 

Pollutant Emissions: Group I Polymers 

and Resins (April 21, 2011, 77 FR 

22579), and the National Emission 

Standards for Organic Hazardous Air 

Pollutants from the Synthetic Organic 

Chemical Manufacturing Industry 

(December 21, 2006, 71 FR 76605). We 

also determined that further reduction 

of dioxin emissions would not be cost 

effective. Due to the low level of current 

risk, the minimal risk reductions that 

could be achieved with the various 

control options that we evaluated, and 

the substantial costs associated with 

additional control options, we are 

proposing that the current standards 

provide an ample margin of safety. 

3. Adverse Environmental Effects 

Based on the results of our 

environmental risk screening 

assessment, we conclude that there is 

not an adverse environmental effect 

from the Portland Cement 

Manufacturing Industry source category. 

We are proposing that it is not necessary 

to set a more stringent standard to 

prevent, taking into consideration costs, 

energy, safety, and other relevant 

factors, an adverse environmental effect. 

C. What are the results and proposed 

decisions based on our technology 

review? 

Control devices typically used to 

minimize emissions at Portland cement 

manufacturing industry facilities 

include fabric filters and electrostatic 

precipitators (ESP) for control of PM 

from kilns; fabric filters for the control 

of PM from clinker coolers and raw 

material handling operations; wet 

scrubbers or dry lime injection for 

control of HCl, and ACI, wet scrubbers, 

or both for the control of mercury, D/F, 

and THC. At least one kiln has 

controlled THC using a wet scrubber 

followed by an RTO. Process changes 

used at some facilities to reduce HAP 

emissions include dust shuttling to 

reduce mercury emissions and raw 

material substitution to reduce organic 

HAP emissions. The add-on controls 

and process changes used by a facility 

to comply with the 40 CFR part 63, 

subpart LLL emission standards are 

highly site specific because of factors 

such as variations in the HAP content of 

raw materials and fuels, availability of 

alternative raw materials and fuels, and 

kiln characteristics (such as age and 

type of kiln). In addition, new or 

reconstructed kilns must also comply 

with the New Source Performance 

Standards (NSPS) for Cement 

Manufacturing (40 CFR part 60, subpart 

F). The NSPS sets limits for emissions 

of PM, nitrogen oxides (NOX) and sulfur 

dioxide (SO2). The PM limits in the 

NSPS and the subpart LLL PM limits for 

new sources are the same. Measures 

taken at a facility to comply with the 

NOX and SO2 limits must be considered 

in light of the subpart LLL emission 

standards. Due to the relatively recent 

finalization of the MACT rules for 

Portland cement manufacturing, there 

have been no new developments in 

practices, processes, or control 

technologies that have been 

implemented in this source category 

since promulgation of the current 

NESHAP. Nevertheless, we did review 

several technologies that have been 

available, or may be available soon, to 

the industry and provided additional 

options to the industry for reducing 

HAP emissions. Based on information 

available to the EPA, these technologies 

do not clearly reduce HAP emissions 

relative to technologies that were 

considered by the EPA when 

promulgating the Portland Cement 

Manufacturing Industry NESHAP in 

2013. 

Selective catalytic reduction (SCR) is 

the process of adding ammonia or urea 

in the presence of a catalyst to 

selectively reduce NOX emissions from 

exhaust gases. A benefit of SCR may be 

its ability to facilitate the removal of 

mercury and other HAP emissions from 

the Portland cement manufacturing 

process. The EPA considered SCR in 

proposing standards for NOX in 2008, 

but did not propose SCR as best 

demonstrated technology for several 

reasons (73 FR 34072, June 16, 2008). At 

the time of the proposal, SCR was in use 

at just a few kilns in Europe, and no 

cement kilns in the U.S. used SCR. 

There were concerns over the plugging 

of the SCR catalyst in high-dust 

installations and, in low-dust 

installations where the catalyst is 

located downstream of the PM control 

device, the cost of reheating cooled 

exhaust was very high leading to 

uncertainties over what actual costs 

would be. Finally, SCR was anticipated 

to increase energy use due to the 


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27 Mercury Control Slipstream Baghouse Testing 

at Ash Grove’s Durkee Cement Facility, September 

2007. 

pressure drop across the catalyst and 

produce additional liquid and solid 

waste to be handled. 

Since then, SCR has been installed on 

two cement kilns in the U.S. The two 

installations in the U.S. started 

operation in 2016 (Holcim in 

Midlothian, Texas) and 2013 (Lafarge in 

Joppa, Illinois). Holcim controls THC 

through addition of SCR to Kiln 1 and 

an RTO to Kiln 2. The SCR system at 

Lafarge controls NOX and operates with 

a long dry kiln with a hot ESP, and no 

reheat. 

Beyond its ability to reduce NOX by 

90 percent, multipollutant benefits have 

been reported. At kilns in Europe, 

reductions in THC of 50 to greater than 

70 percent have been reported. 

Although D/F reductions have been 

observed for SCR in many industries 

and reductions in D/F have been 

reported for an SCR installation at a 

cement kiln in Italy, tests of D/F 

reduction across SCR catalyst in the 

Portland Cement Manufacturing 

Industry have not been conducted. SCR 

does not directly reduce mercury 

emissions. Instead, SCR results in the 

oxidation of mercury from its elemental 

form, and the oxidized form is more 

easily captured in scrubbers. The 

addition of an SCR as control is 

expected to have little impact on 

reducing mercury emissions from 

cement kilns without requiring the 

addition of a scrubber system. 

Catalytic ceramic filter candles and 

catalytic filter bags are used to remove 

not only particulate, but may be used to 

remove other pollutants such as D/F, 

THC, non-D/F organic HAP, carbon 

monoxide (CO), and NOX. Catalytic 

ceramic filter candles are typically 

approximately 10 feet long. The length 

is limited to 10 feet by several 

considerations, including the weight of 

the candle and the fact that the candle 

cannot be flexed, limiting the height 

above the seal plate. In contrast, the 

length of catalytic filter bags can vary 

from 10 to 32 feet. Currently, filter bags 

at cement manufacturing facilities are 

much longer than 10 feet. Therefore, 

installing ceramic filter candles can 

only be done by replacing the baghouse 

housing (i.e., ceramic filter candles are 

not a drop-in replacement for existing 

filter bags). 

FLSmidth received the first contract 

for removal of THC with ceramic 

catalytic filters at a U.S. cement kiln. 

They noted that the removal of THC 

with their ceramic catalytic filter system 

depends on the speciation of THC 

components, but that removal 

efficiencies of greater than 90 percent 

have been seen in testing for HAP THC 

pollutants. Tri-Mer Corp., a technology 

company specializing in advanced 

industrial air pollution control systems, 

claims to have fully commercialized a 

ceramic filter technology that is highly 

effective for emissions from cement 

kilns and other processes facing 

NESHAP and MACT compliance issues. 

Although no studies were identified in 

the literature documenting the 

performance of Tri-Mer’s ceramic filter 

system, the company states that their 

catalyst filter system is highly efficient 

at removing PM, SO2, HCl, mercury, and 

heavy metals, while simultaneously 

destroying NOX, cement organic HAP 

and D/F. Tri-Mer reports NOX removal 

at up to 95 percent and D/F removal 

typically over 97 percent. The system 

can incorporate dry sorbent injection of 

hydrated lime, sodium bicarbonate, or 

trona for dry scrubbing of SO2, HCI, HF, 

and other acid gases. With dry sorbent 

injection, typical SO2 and HCl results 

show 90- to 98-percent removal. 

According to company information, the 

control of any combination of these 

pollutants is accomplished in a single, 

completely dry system that is suitable 

for all flow volumes. 

Powdered activated carbon (PAC) for 

mercury control was first used in the 

U.S. for the incinerator (waste-toenergy) industry. Conventional PAC was 

expected to be used for mercury control 

for electrical power generation. 

However, conventional PAC mercury 

removal performance suffers in 

situations involving high-sulfur coal, 

which leads to high sulfur trioxide (SO3) 

levels, or situations where SO3 is 

injected to improve ESP performance. In 

addition, a September 2007 test 

conducted at the Ash Grove facility in 

Durkee, Oregon, suggests that halogentreated PAC makes no difference in 

controlling mercury emissions from a 

kiln. Specifically, the report states, 

‘‘While studies at coal-fired power 

plants have indicated that the use of 

halogen-treated PAC can result in higher 

Hg control efficiencies, testing on the 

Durkee exhaust gas indicated that 

untreated carbon provides equivalent 

control to halogen-treated carbon. This 

is believed to be due to the low sulfur 

levels in the Durkee cement kiln 

exhaust gases as compared to coal-fired 

power plants.’’ 27 We believe that, based 

on our review, the addition of 

halogenated PAC controls to further 

reduce mercury emissions do not result 

in a substantial reduction of mercury 

emissions beyond current controls. 

The Ash Grove facility in Durkee, 

Oregon, had the highest mercury 

emissions of any Portland cement 

manufacturing facility prior to 

promulgation of the cement NESHAP. 

To reach the NESHAP limit of 55 lbs 

mercury per million tons of clinker, Ash 

Grove installed a $20 million system for 

mercury capture. It consists of a 

baghouse with ACI. Dust collected in 

the baghouse is sent to an electric 

furnace where it is heated to 800 

degrees Fahrenheit, which puts the 

mercury back into a gaseous state. The 

gaseous mercury moves into a cooling 

chamber where it is converted into 

liquid that is captured in a heat 

exchanger/condenser. The liquid 

mercury is then sold for use in 

electronic devices and other products. 

Praxair has developed a technology of 

feeding a stream of hot oxygen into a 

cement kiln to lower emissions of CO 

and hydrocarbons. This technology 

involves oxidation of CO at the kiln 

inlet with oxygen enhanced 

combustion, and has been in 

commercial practice since 2014 at a kiln 

in Europe. It has not been installed on 

any cement kiln in the U.S. Oxygen is 

injected in the riser with the goal of 

lowering NOX and CO emissions to 

below permitted levels of 230 

milligrams per normal cubic meter (mg/ 

Nm3) and 4,000 mg/Nm3, respectively, 

without use of a more expensive SCR 

system. 

As discussed before, there are several 

technologies that can be effective in 

reducing emission from the cement kiln. 

However, most of these technologies 

have not been widely used in the 

industry so source category specific data 

on their long term performance and 

costs are lacking. Their performance is 

typically similar to technologies already 

employed or, in some cases, only 

marginally better. In the case of SCR, it 

had been noted that this might be an 

alternative to current THC controls. 

However, we note that SCR is most 

effective on non-dioxin organic HAP 

and is not effective on other 

hydrocarbons. The organic HAP portion 

of the 24 parts per million by volume 

THC limit is typically low and is near 

the actual detection limits for 

measurement. Therefore, even if SCR 

were more widely applied in the 

industry, the emissions impact on THC 

and organic HAP would be small. 

D. What other actions are we proposing? 

In addition to the proposed actions 

described above, we are proposing 

additional revisions, which include 

changes to clarify monitoring, testing, 

and recordkeeping and reporting 

requirements and the correction of 

typographical errors. Our analyses and 


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28 Van den Berg, Martin, et al. The 2005 World 

Health Organization Re-evaluation of Human and 

Mammalian Toxic Equivalency Factors for Dioxins 

and Dioxin-like Compounds. Toxicol. Sci. 2006, 

October 1993(2): 223–241. 

proposed changes related to these issues 

are discussed below. 

We are proposing to correct a 

paragraph in the reporting requirements 

that mistakenly requires that affected 

sources report their 30-operating day 

rolling average for D/F temperature 

monitoring. There are no 30-day 

operating rolling average temperature 

requirements pertaining to D/F in the 

rule. The removal of the reference to the 

D/F temperature monitoring system in 

40 CFR 63.1354(b)(9)(vi) is also 

consistent with the EPA’s October 2016 

rule guidance for the subpart LLL 

NESHAP. See NESHAP for the Portland 

Cement Manufacturing Industry Subpart 

LLL Rule Guidance, which has been 

updated to include revisions from this 

proposed rule. (https://www.epa.gov/ 

sites/production/files/2016-03/ 

documents/ruleguidance_mar2016.pdf.) 

We are proposing to correct a 

provision that requires facility owners 

or operators to keep records of both 

daily clinker production and kiln feed 

rates. Section 63.1350(d)(1)(ii) requires 

daily kiln feed rate records only if the 

facility derives their clinker production 

rates from the measured feed rate. 

The EPA is proposing to clarify that 

the submittal dates for semiannual 

summary reports required under 40 CFR 

63.1354(b)(9) are 60 days after the end 

of the reporting period consistent with 

the Agency’s statement in the October 

2016 rule guidance for the subpart LLL 

NESHAP. In addition, the October 2016 

rule guidance was revised in September 

2017 to ensure it reflects the various 

changes proposed in this rule. 

The EPA is proposing to resolve 

conflicting provisions that apply when 

an SO2 continuous parametric 

monitoring system is used to monitor 

HCl compliance. If the SO2 level 

exceeds by 10 percent or more the sitespecific SO2 emissions limit, 40 CFR 

63.1349(b)(x) requires that as soon as 

possible, but within 30 days, a facility 

must take corrective action, and within 

90 days, conduct a performance test to 

demonstrate compliance with the HCl 

limit and verify or re-establish the sitespecific SO2 emissions limit. These 

conflict with 40 CFR 63.1350(l)(3), 

which requires corrective action within 

48 hours and retesting within 60 days. 

We are proposing to adopt the 

requirements of 40 CFR 63.1349(b)(x) 

and change the requirement of 40 CFR 

63.1350(l)(3) to reflect this. 

We are proposing to clarify the 

requirement in section 63.1349(b)(1)(vi) 

which states that for each PM 

performance test, an owner or operator 

must conduct at least three separate test 

runs each while the mill is on and the 

mill is off. We are proposing that this 

provision only applies to kilns with 

inline raw mills, as inline raw mills are 

considered part of the kiln and can 

affect kiln PM emissions. It specifically 

would not apply to a kiln that does not 

have an inline raw mill or to a clinker 

cooler (unless the clinker cooler gases 

are combined with kiln exhaust and 

sent through an inline mill). As in these 

cases, the raw mill is a separate source 

from the kiln and has no effect on kiln 

or clinker cooler PM emissions. 

We are proposing changes which 

affect the emission limits for D/F. Table 

1 of 40 CFR 63.1343(b) lists the 

emission limits for D/F. The units of the 

emission limit are ng/dscm TEQ at 7- 

percent oxygen. The TEQ is developed 

by determining the mass of each 

congener measured during the 

performance test, then multiplying each 

congener by the toxic equivalency factor 

(TEF). After the TEQ is developed per 

congener, they are added to obtain the 

total TEQs. The TEFs were re-evaluated 

in 2005 by the World Health 

Organization—International Programme 

on Chemical Safety using a different 

scale of magnitude.28 The 40 CFR part 

63, subpart LLL standards were 

developed based on TEFs developed in 

1989, as referenced in the TEQ 

definition section of the rule (40 CFR 

63.1341). Laboratories calculating the 

TEQs should be using the TEFs 

developed in 1989. We are proposing 

that the 1989 TEFs be incorporated into 

the rule to clarify that they are the 

appropriate factors for calculating TEQ. 

Finally, we are proposing to clarify 

the performance test requirements for 

certain sources. According to a 

stakeholder, compliance with 40 CFR 

part 63, subpart LLL is required 

immediately upon startup and does not 

allow companies an operating window 

after periods of extended shutdown in 

order to assess compliance. The 

stakeholder states that extended 

shutdowns of existing kilns occur in the 

Portland cement manufacturing 

industry in the aftermath of economic 

downturns when companies have halted 

production at certain facilities. When 

the economy rebounds and sources are 

brought back on line, they must 

immediately comply with NESHAP and 

other CAA requirements for existing 

facilities. The stakeholder asserts that 

this mandatory compliance requirement 

does not account for the fact that owners 

or operators must start the facilities back 

up and run them for periods of time to 

determine whether any measures must 

be taken to come into compliance with 

updated NESHAP or other standards. In 

response, we are proposing to clarify the 

performance test requirements for 

affected sources that have been idle 

through one or more periods that 

required a performance test to 

demonstrate compliance. The proposed 

amendment would require any affected 

source that was unable to demonstrate 

compliance before the compliance date 

due to being idled, or that had 

demonstrated compliance, but was idled 

during the normal window for the next 

compliance test, to demonstrate 

compliance with the emissions 

standards and operating limits by 

conducting their performance using the 

test methods and procedures in 40 CFR 

63.1349 and 63.7. Per 40 CFR 63.7, the 

necessary performance tests would need 

to be completed within 180 days of the 

date that compliance must be 

demonstrated. 

E. What compliance dates are we 

proposing? 

Because these amendments only 

provide corrections and clarifications to 

the current rule and do not impose new 

requirements on the industry, we are 

proposing that these amendments 

become effective upon promulgation of 

the final rule. 

V. Summary of Cost, Environmental, 

and Economic Impacts 

A. What are the impacts to affected 

sources? 

The recent amendments to the 

Portland Cement Manufacturing 

NESHAP have included rule updates, 

addressing electronic reporting 

requirements, and changes in policies 

regarding startup, shutdown, and 

malfunction. Because we are proposing 

no new requirements or controls in this 

RTR, no Portland cement manufacturing 

facilities are adversely impacted by 

these proposed revisions. In fact, the 

impacts to the Portland cement 

manufacturing industry from this 

proposal will be minimal and 

potentially positive. 

B. What are the air quality impacts? 

In this proposal, we recommend no 

new emission limits and require no 

additional controls; therefore, no air 

quality impacts are expected as a result 

of the proposed amendments. 

C. What are the cost impacts? 

As previously stated, recent 

amendments to the Portland Cement 

Manufacturing NESHAP have addressed 

electronic reporting and changes in 

policies regarding startup, shutdown, 

and malfunction. Additionally, the 


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proposed amendments recommend no 

changes to emission standards or add-on 

controls. Therefore, the proposed 

amendments impose no additional 

costs. In fact, the clarifications to rule 

language may actually result in a 

reduction of current costs because 

compliance will be more 

straightforward. 

D. What are the economic impacts? 

No economic impacts are expected as 

a result of the proposed amendments. 

E. What are the benefits? 

While the proposed amendments 

would not result in reductions in 

emissions of HAP, this action, if 

finalized, would result in improved 

monitoring, compliance, and 

implementation of the rule. 

VI. Request for Comments 

We solicit comments on all aspects of 

this proposed action. In addition to 

general comments on this proposed 

action, we are also interested in 

additional data that may improve the 

risk assessments and other analyses. We 

are specifically interested in receiving 

any improvements to the data used in 

the site-specific emissions profiles used 

for risk modeling. Such data should 

include supporting documentation in 

sufficient detail to allow 

characterization of the quality and 

representativeness of the data or 

information. Section VII of this 

preamble provides more information on 

submitting data. 

VII. Submitting Data Corrections 

The site-specific emissions profiles 

used in the source category risk and 

demographic analyses and instructions 

are available for download on the RTR 

Web site at https://www3.epa.gov/ttn/ 

atw/rrisk/rtrpg.html. The data files 

include detailed information for each 

HAP emissions release point for the 

facilities in the source category. 

If you believe that the data are not 

representative or are inaccurate, please 

identify the data in question, provide 

your 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 site, 

complete the following steps: 

1. Within this downloaded file, enter 

suggested revisions to the data fields 

appropriate for that information. 

2. Fill in the commenter information 

fields for each suggested revision (i.e., 

commenter name, commenter 

organization, commenter email 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 

documentation to Docket ID No. EPA– 

HQ–OAR–2016–0442 (through the 

method described in the ADDRESSES

section of this preamble). 

5. If you are providing comments on 

a single facility or multiple facilities, 

you need only submit one file for all 

facilities. The file should contain all 

suggested changes for all sources at that 

facility. We request that all data revision 

comments be submitted in the form of 

updated Microsoft® Excel files that are 

generated by the Microsoft® Access file. 

These files are provided on the RTR 

Web site at https://www3.epa.gov/ttn/ 

atw/rrisk/rtrpg.html. 

VIII. Statutory and Executive Order 

Reviews 

Additional information about these 

statutes and Executive Orders can be 

found at http://www2.epa.gov/lawsregulations/laws-and-executive-orders. 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

This action is not a significant 

regulatory action and was, therefore, not 

submitted to the Office of Management 

and Budget (OMB) for review. 

B. Executive Order 13771: Reducing 

Regulations and Controlling Regulatory 

Costs 

This action is not expected to be an 

Executive Order 13771 regulatory action 

because this action is not significant 

under Executive Order 12866. 

C. Paperwork Reduction Act (PRA) 

This action does not impose any new 

information collection burden under the 

PRA. OMB has previously approved the 

information collection activities 

contained in the existing regulations (40 

CFR part 63, subpart LLL) and has 

assigned OMB control number 2060– 

0416. This action does not change the 

information collection requirements. 

D. Regulatory Flexibility Act (RFA) 

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. In making this 

determination, the impact of concern is 

any significant adverse economic 

impact on small entities. An agency may 

certify that a rule will not have a 

significant economic impact on a 

substantial number of small entities if 

the rule relieves regulatory burden, has 

no net burden, or otherwise has a 

positive economic effect on the small 

entities subject to the rule. We estimate 

that three of the 26 existing Portland 

cement entities are small entities and 

comprise three plants. After considering 

the economic impacts of this proposed 

action on small entities, we have 

concluded that this action will have no 

net regulatory burden for all directly 

regulated small entities. 

E. Unfunded Mandates Reform Act 

(UMRA) 

This action does not contain an 

unfunded mandate as described in 

UMRA, 2 U.S.C. 1531–1538, and does 

not significantly or uniquely affect small 

governments. The action imposes no 

enforceable duty on any state, local, or 

tribal governments or the private sector. 

F. Executive Order 13132: Federalism 

This action 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. 

G. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does not have tribal 

implications as specified in Executive 

Order 13175. It will neither impose 

substantial direct compliance costs on 

federally recognized tribal governments, 

nor preempt tribal law. The EPA is 

aware of one tribally owned Portland 

cement facility currently subject to 40 

CFR part 63, subpart LLL that will be 

subject to this proposed action. 

However, the provisions of this 

proposed rule are not expected to 

impose new or substantial direct 

compliance costs on tribal governments 

since the provisions in this proposed 

action are clarifying and correcting 

monitoring and testing requirements 

and recordkeeping and reporting 

requirements. This proposed action also 

provides clarification for owners and 

operators on bringing new or previously 

furloughed kilns back on line. Thus, 

Executive Order 13175 does not apply 

to this action. 


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H. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

The EPA interprets Executive Order 

13045 as applying only to those 

regulatory actions that concern 

environmental health or safety risks that 

the EPA has reason to believe may 

disproportionately affect children, per 

the definition of ‘‘covered regulatory 

action’’ in section 2–202 of the 

Executive Order. This action is not 

subject to Executive Order 13045 

because it does not concern an 

environmental health risk or safety risk. 

I. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not subject to Executive 

Order 13211 because it is not a 

significant regulatory action under 

Executive Order 12866. 

J. National Technology Transfer and 

Advancement Act (NTTAA) 

This rulemaking does not involve 

technical standards. 

K. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

The EPA believes that this action does 

not have disproportionately high and 

adverse human health or environmental 

effects on minority populations, lowincome populations, and/or indigenous 

peoples, as specified in Executive Order 

12898 (59 FR 7629, February 16, 1994). 

The documentation for this decision is 

contained in section IV.A of this 

preamble. 

List of Subjects in 40 CFR Part 63 

Environmental protection, 

Administrative practices and 

procedures, Air pollution control, 

Hazardous substances, 

Intergovernmental relations, Reporting 

and recordkeeping requirements. 

Dated: September 1, 2017. 

E. Scott Pruitt, 

Administrator. 

For the reasons stated in the 

preamble, the Environmental Protection 

Agency is proposing to amend title 40, 

chapter I, part 63 of the Code of Federal 

Regulations (CFR) as follows: 

PART 63—NATIONAL EMISSION 

STANDARDS FOR HAZARDOUS AIR 

POLLUTANTS FOR SOURCE 

CATEGORIES 

■ 1. The authority citation for part 63 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

Subpart LLL—National Emission 

Standards for Hazardous Air Pollutants 

for the Portland Cement Manufacturing 

Industry 

■ 2. Section 63.1341 is amended by: 

■ a. Removing the definition of 

‘‘affirmative defense;’’ and 

■ b. Revising the definitions of ‘‘dioxins 

and furans (D/F),’’ ‘‘in-line coal mill,’’ 

and ‘‘TEQ.’’ 

The revisions read as follows: 

§ 63.1341 Definitions 

* * * * * 

Dioxins and furans (D/F) means 

tetra-, penta-, hexa-, hepta-, and octachlorinated dibenzo dioxins and furans. 

* * * * * 

In-line coal mill means a coal mill 

using kiln exhaust gases in their 

process. A coal mill with a heat source 

other than the kiln or a coal mill using 

exhaust gases from the clinker cooler is 

not an in-line coal mill. 

* * * * * 

TEQ means the international method 

of expressing toxicity equivalents for 

dioxins and furans as defined in U.S. 

EPA, Interim Procedures for Estimating 

Risks Associated with Exposures to 

Mixtures of Chlorinated Dibenzo-pdioxins and -dibenzofurans (CDDs and 

CDFs) and 1989 Update, March 1989. 

The 1989 Toxic Equivalency Factors 

(TEFs) used to determine the dioxin and 

furan TEQs are listed in Table 2 to 

subpart LLL of Part 63. 

* * * * * 

§ 63.1343 [Amended] 

■ 3. Section 63.1343 is amended by 

removing paragraph (d) and Table 2. 

■ 4. Section 63.1348 is amended by: 

■ a. Revising the first sentence in 

paragraph (a) introductory text; 

■ b. Revising paragraph (a)(3)(i); 

■ c. Revising the second sentence in 

paragraph (a)(3)(iv); 

■ d. Revising paragraphs (a)(4)(ii), 

(a)(7)(ii), (b)(3)(ii), and (b)(4); 

■ e. Redesignating paragraph (b)(5)(i) as 

paragraph (b)(5) introductory text; 

■ f. Revising newly redesignated 

paragraph (b)(5) introductory text; and 

■ g. Adding new paragraph (b)(5)(i). 

The revisions and addition read as 

follows: 

§ 63.1348 Compliance requirements. 

(a) Initial Performance Test 

Requirements. For an affected source 

subject to this subpart, including any 

affected source that was unable to 

demonstrate compliance before the 

compliance date due to being idled, or 

that had demonstrated compliance but 

was idled during the normal window for 

the next compliance test, you must 

demonstrate compliance with the 

emissions standards and operating 

limits by using the test methods and 

procedures in §§ 63.1349 and 63.7. 

* * * * * 

(3) D/F compliance. (i) If you are 

subject to limitations on D/F emissions 

under § 63.1343(b), you must 

demonstrate initial compliance with the 

D/F emissions standards by using the 

performance test methods and 

procedures in § 63.1349(b)(3). The 

owner or operator of a kiln with an inline raw mill must demonstrate initial 

compliance by conducting separate 

performance tests while the raw mill is 

operating and the raw mill is not 

operating. Determine the D/F TEQ 

concentration for each run and calculate 

the arithmetic average of the TEQ 

concentrations measured for the three 

runs to determine continuous 

compliance. 

* * * * * 

(iv) * * * Compliance is 

demonstrated if the system is 

maintained within ±5 percent accuracy 

during the performance test determined 

in accordance with the procedures and 

criteria submitted for review in your 

monitoring plan required in 

§ 63.1350(p). 

(4) * * * 

(ii) Total Organic HAP Emissions 

Tests. If you elect to demonstrate 

compliance with the total organic HAP 

emissions limit under § 63.1343(b) in 

lieu of the THC emissions limit, you 

must demonstrate compliance with the 

total organic HAP emissions standards 

by using the performance test methods 

and procedures in § 63.1349(b)(7). 

* * * * * 

(7) * * * 

(ii) Perform required emission 

monitoring and testing of the kiln 

exhaust prior to the reintroduction of 

the coal mill exhaust, and also testing 

the kiln exhaust diverted to the coal 

mill. All emissions must be added 

together for all emission points, and 

must not exceed the limit per each 

pollutant as listed in § 63.1343(b). 

(b) * * * 

(3) * * * 

(ii) Bag Leak Detection System 

(BLDS). If you install a BLDS on a raw 

mill or finish mill in lieu of conducting 

the daily visible emissions testing, you 

must demonstrate compliance using a 

BLDS that is installed, operated, and 

maintained in accordance with the 

requirements of § 63.1350(f)(4)(ii). 

(4) D/F Compliance. If you are subject 

to a D/F emissions limitation under 

§ 63.1343(b), you must demonstrate 


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compliance using a continuous 

monitoring system (CMS) that is 

installed, operated and maintained to 

record the temperature of specified gas 

streams in accordance with the 

requirements of § 63.1350(g). 

(5) Activated Carbon Injection 

Compliance. (i) If you use activated 

carbon injection to comply with the D/ 

F emissions limitation under 

§ 63.1343(b), you must demonstrate 

compliance using a CMS that is 

installed, operated, and maintained to 

record the rate of activated carbon 

injection in accordance with the 

requirements § 63.1350(h)(1). 

* * * * * 

■ 5. Section 63.1349 is amended by: 

■ a. Revising paragraphs (b)(1)(vi), 

(3)(iv), (4)(i), (6)(i)(A), (7)(viii)(A), 

(8)(vi), and (8)(vii)(B); and 

■ b. Removing and reserving paragraph 

(d). 

The revisions read as follows: 

§ 63.1349 Performance testing 

requirements. 

* * * * * 

(b)(1) * * * 

(vi) For each performance test, 

conduct at least three separate test runs 

under the conditions that exist when the 

affected source is operating at the level 

reasonably expected to occur. Conduct 

each test run to collect a minimum 

sample volume of 2 dscm for 

determining compliance with a new 

source limit and 1 dscm for determining 

compliance with an existing source 

limit. Calculate the time weighted 

average of the results from three 

consecutive runs, including applicable 

sources as required by paragraph 

(b)(1)(viii) of this section, to determine 

compliance. You need not determine 

the particulate matter collected in the 

impingers ‘‘back half’’ of the Method 5 

or Method 5I particulate sampling train 

to demonstrate compliance with the PM 

standards of this subpart. This shall not 

preclude the permitting authority from 

requiring a determination of the ‘‘back 

half’’ for other purposes. For kilns with 

inline raw mills, testing must be 

conducted while the raw mill is on and 

while the raw mill is off. If the exhaust 

streams of a kiln with an inline raw mill 

and a clinker cooler are comingled, then 

the comingled exhaust stream must be 

tested with the raw mill on and the raw 

mill off. 

* * * * * 

(3) * * * 

(iv) The run average temperature must 

be calculated for each run, and the 

average of the run average temperatures 

must be determined and included in the 

performance test report and will 

determine the applicable temperature 

limit in accordance with § 63.1346(b). 

* * * * * 

(4) * * * 

(i) If you are subject to limitations on 

THC emissions, you must operate a 

CEMS in accordance with the 

requirements in § 63.1350(i). For the 

purposes of conducting the accuracy 

and quality assurance evaluations for 

CEMS, the THC span value (as propane) 

is 50 to 60 ppmvw and the reference 

method (RM) is Method 25A of 

appendix A to part 60 of this chapter. 

* * * * * 

(6) * * * 

(i)(A) If the source is equipped with 

a wet scrubber, tray tower or dry 

scrubber, you must conduct 

performance testing using Method 321 

of appendix A to this part unless you 

have installed a CEMS that meets the 

requirements § 63.1350(l)(1). For kilns 

with inline raw mills, testing must be 

conducted for the raw mill on and raw 

mill off conditions. 

* * * * * 

(7) * * * 

(viii) * * * 

(A) Determine the THC CEMS average 

values in ppmvw, and the average of 

your corresponding three total organic 

HAP compliance test runs, using 

Equation 12. 

Where: 

x ̄ = The THC CEMS average values in 

ppmvw. 

Xi = The THC CEMS data points for all three 

test runs i. 

y ̄ = The organic HAP average values in 

ppmvw. 

Yi = The organic HAP concentrations for all 

three test runs i. 

n = The number of data points. 

* * * * * 

(8) * * * 

(vi) If your kiln has an inline kiln/raw 

mill, you must conduct separate 

performance tests while the raw mill is 

operating (‘‘mill on’’) and while the raw 

mill is not operating (‘‘mill off’’). Using 

the fraction of time the raw mill is on 

and the fraction of time that the raw 

mill is off, calculate this limit as a 

weighted average of the SO2 levels 

measured during raw mill on and raw 

mill off compliance testing with 

Equation 17. 

Where: 

R = Operating limit as SO2, ppmvw. 

y = Average SO2 CEMS value during mill on 

operations, ppmvw. 

t = Percentage of operating time with mill on, 

expressed as a decimal. 

x = Average SO2 CEMS value during mill off 

operations, ppmvw. 

1-t = Percentage of operating time with mill 

off, expressed as a decimal. 

(vii) * * * 

(B) Determine your SO2 CEMS 

instrument average ppm, and the 

average of your corresponding three HCl 

compliance test runs, using equation 18. 


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Where: 

x ̄= The SO2 CEMS average values in ppmvw. 

X1 = The SO2 CEMS data points for the three 

runs constituting the performance test. 

y ̄ = The HCl average values in ppmvw. 

Y1 = The HCl emission concentration 

expressed as ppmv corrected to 7 percent 

oxygen for the three runs constituting the 

performance test. 

n = The number of data points. 

* * * * * 

(d) [Reserved] 

* * * * * 

■ 6. Section 63.1350 is amended by: 

■ a. Revising paragraphs (g) 

introductory text, (g)(4), (h)(2)(ii), (j), 

(k)(2) introductory text, (k)(2)(ii), and 

(k)(2)(iii); and 

■ b. Revising paragraphs (k)(5)(ii), (l)(1) 

introductory text, and (l)(3). 

The revisions read as follows: 

§ 63.1350 Monitoring requirements. 

* * * * * 

(g) D/F monitoring requirements. If 

you are subject to an emissions 

limitation on D/F emissions, you must 

comply with the monitoring 

requirements of paragraphs (g)(1) 

through (g)(5) and paragraphs (m)(1) 

through (m)(4) of this section to 

demonstrate continuous compliance 

with the D/F emissions standard. You 

must also develop an emissions 

monitoring plan in accordance with 

paragraphs (p)(1) through (p)(4) of this 

section. 

* * * * * 

(4) Every hour, report the calculated 

rolling three-hour average temperature 

using the average of 180 successive oneminute average temperatures. See 

S63.1349(b)(3). 

* * * * * 

(h) * * * 

(2) * * * 

(ii) Each hour, calculate the threehour rolling average of the selected 

parameter value for the previous 3 hours 

of process operation using all of the oneminute data available (i.e., the CMS is 

not out-of-control). 

* * * * * 

(j) Total organic HAP monitoring 

requirements. If you are complying with 

the total organic HAP emissions limits, 

you must continuously monitor THC 

according to paragraph (i)(1) and (2) of 

this section or in accordance with 

Performance Specification 8 or 

Performance Specification 8A of 

appendix B to part 60 of this chapter 

and comply with all of the requirements 

for continuous monitoring systems 

found in the general provisions, subpart 

A of this part. You must operate and 

maintain each CEMS according to the 

quality assurance requirements in 

Procedure 1 of appendix F in part 60 of 

this chapter. You must also develop an 

emissions monitoring plan in 

accordance with paragraphs (p)(1) 

through (4) of this section. 

(k) * * * 

(2) In order to quality assure data 

measured above the span value, you 

must use one of the three options in 

paragraphs (k)(2)(i) through (iii) of this 

section. 

* * * * * 

(ii) Quality assure any data above the 

span value by proving instrument 

linearity beyond the span value 

established in paragraph (k)(1) of this 

section using the following procedure. 

Conduct a weekly ‘‘above span 

linearity’’ calibration challenge of the 

monitoring system using a reference gas 

with a certified value greater than your 

highest expected hourly concentration 

or greater than 75 percent of the highest 

measured hourly concentration. The 

‘‘above span’’ reference gas must meet 

the requirements of PS 12A, Section 7.1 

and must be introduced to the 

measurement system at the probe. 

Record and report the results of this 

procedure as you would for a daily 

calibration. The ‘‘above span linearity’’ 

challenge is successful if the value 

measured by the Hg CEMS falls within 

10 percent of the certified value of the 

reference gas. If the value measured by 

the Hg CEMS during the above span 

linearity challenge exceeds ±10 percent 

of the certified value of the reference 

gas, the monitoring system must be 

evaluated and repaired and a new 

‘‘above span linearity’’ challenge met 

before returning the Hg CEMS to 

service, or data above span from the Hg 

CEMS must be subject to the quality 

assurance procedures established in 

paragraph (k)(2)(iii) of this section. In 

this manner all hourly average values 

exceeding the span value measured by 

the Hg CEMS during the week following 

the above span linearity challenge when 

the CEMS response exceeds ±20 percent 

of the certified value of the reference gas 

must be normalized using Equation 22. 

(iii) Quality assure any data above the 

span value established in paragraph 

(k)(1) of this section using the following 

procedure. Any time two consecutive 

one-hour average measured 

concentrations of Hg exceeds the span 

value you must, within 24 hours before 

or after, introduce a higher, ‘‘above 

span’’ Hg reference gas standard to the 

Hg CEMS. The ‘‘above span’’ reference 

gas must meet the requirements of PS 

12A, Section 7.1, must target a 

concentration level between 50 and 150 

percent of the highest expected hourly 

concentration measured during the 

period of measurements above span, 

and must be introduced at the probe. 

While this target represents a desired 

concentration range that is not always 

achievable in practice, it is expected 

that the intent to meet this range is 

demonstrated by the value of the 

reference gas. Expected values may 

include ‘‘above span’’ calibrations done 

before or after the above span 

measurement period. Record and report 

the results of this procedure as you 

would for a daily calibration. The 

‘‘above span’’ calibration is successful if 

the value measured by the Hg CEMS is 

within 20 percent of the certified value 

of the reference gas. If the value 

measured by the Hg CEMS exceeds 20 

percent of the certified value of the 

reference gas, then you must normalize 

the one-hour average stack gas values 

measured above the span during the 24- 

hour period preceding or following the 

‘‘above span’’ calibration for reporting 

based on the Hg CEMS response to the 

reference gas as shown in equation 22. 

Only one ‘‘above span’’ calibration is 

needed per 24 hour period. 

* * * * * 

(5) * * * 

(ii) On a continuous basis, determine 

the mass emissions of mercury in lb/hr 

from the alkali bypass and coal mill 

exhausts by using the mercury hourly 

emissions rate and the exhaust gas flow 

rate to calculate hourly mercury 

emissions in lb/hr. 

* * * * * 

(l) * * * 

(1) If you monitor compliance with 

the HCl emissions limit by operating an 

HCl CEMS, you must do so in 

accordance with Performance 

Specification 15 (PS 15) or PS 18 of 

appendix B to part 60 of this chapter, or, 


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44284 Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules 

upon promulgation, in accordance with 

any other performance specification for 

HCl CEMS in appendix B to part 60 of 

this chapter. You must operate, 

maintain, and quality assure a HCl 

CEMS installed and certified under PS 

15 according to the quality assurance 

requirements in Procedure 1 of 

appendix F to part 60 of this chapter 

except that the Relative Accuracy Test 

Audit requirements of Procedure 1 must 

be replaced with the validation 

requirements and criteria of sections 

11.1.1 and 12.0 of PS 15. If you choose 

to install and operate an HCl CEMS in 

accordance with PS 18 of appendix B to 

part 60 of this chapter, you must 

operate, maintain, and quality assure 

the HCl CEMS using the associated 

Procedure 6 of appendix F to part 60 of 

this chapter. For any performance 

specification that you use, you must use 

Method 321 of appendix A to part 63 of 

this chapter as the reference test method 

for conducting relative accuracy testing. 

The span value and calibration 

requirements in paragraphs (l)(1)(i) and 

(ii) of this section apply to HCl CEMS 

other than those installed and certified 

under PS 15 or PS 18. 

* * * * * 

(3) If the source is equipped with a 

wet or dry scrubber or tray tower, and 

you choose to monitor SO2 emissions, 

monitor SO2 emissions continuously 

according to the requirements of 

§ 60.63(e) and (f) of part 60 subpart F of 

this chapter. If SO2 levels increase above 

the 30-day rolling average SO2 operating 

limit established during your 

performance test by 10 percent or more, 

you must: 

(i) As soon as possible but no later 

than 30 days after you exceed the 

established SO2 value conduct an 

inspection and take corrective action to 

return the SO2 emissions to within the 

operating limit; and 

(ii) Within 90 days of the exceedance 

or at the time of the next compliance 

test, whichever comes first, conduct an 

HCl emissions compliance test to 

determine compliance with the HCl 

emissions limit and to verify or reestablish the SO2 CEMS operating limit. 

* * * * * 

■ 7. Section 63.1354 is amended by 

revising paragraph (b)(9) introductory 

text, (9)(vi), (9)(viii), and (10); and 

paragraph (c) to read as follows: 

§ 63.1354 Reporting requirements. 

* * * * * 

(b) * * * 

(9) The owner or operator shall 

submit a summary report semiannually 

within 60 days of the reporting period 

to the EPA via the Compliance and 

Emissions Data Reporting Interface 

(CEDRI). (CEDRI can be accessed 

through the EPA’s Central Data 

Exchange (CDX) (www.epa.gov/cdx).) 

You must use the appropriate electronic 

report in CEDRI for this subpart. Instead 

of using the electronic report in CEDRI 

for this subpart, you may submit an 

alternate electronic file consistent with 

the extensible markup language (XML) 

schema listed on the CEDRI Web site 

(https://www.epa.gov/electronicreporting-air-emissions/complianceand-emissions-data-reporting-interfacecedri), once the XML schema is 

available. If the reporting form specific 

to this subpart is not available in CEDRI 

at the time that the report is due, you 

must submit the report the 

Administrator at the appropriate 

address listed in § 63.13. You must 

begin submitting reports via CEDRI no 

later than 90 days after the form 

becomes available in CEDRI. The excess 

emissions and summary reports must be 

submitted no later than 60 days after the 

end of the reporting period, regardless 

of the method in which the reports are 

submitted. The report must contain the 

information specified in 

§ 63.10(e)(3)(vi). In addition, the 

summary report shall include: 

* * * * * 

(vi) For each PM CPMS, HCl, Hg, and 

THC CEMS, or Hg sorbent trap 

monitoring system, within 60 days after 

the reporting periods, you must report 

all of the calculated 30-operating day 

rolling average values derived from the 

CPMS, CEMS, CMS, or Hg sorbent trap 

monitoring systems. 

* * * * * 

(viii) You must submit the 

information specified in paragraphs 

(b)(9)(viii)(A) and (B) of this section no 

later than 60 days following the initial 

performance test. All reports must be 

signed by a responsible official. 

(A) The initial performance test data 

as recorded under § 63.1349(a). 

(B) The values for the site-specific 

operating limits or parameters 

established pursuant to § 63.1349(b)(1), 

(3), (6), (7), and (8), as applicable, and 

a description, including sample 

calculations, of how the operating 

parameters were established during the 

initial performance test. 

(C) As of December 31, 2011, and 

within 60 days after the date of 

completing each performance 

evaluation or test, as defined in § 63.2, 

conducted to demonstrate compliance 

with any standard covered by this 

subpart, you must submit the relative 

accuracy test audit data and 

performance test data, except opacity 

data, to the EPA by successfully 

submitting the data electronically to the 

EPA’s Central Data Exchange (CDX) by 

using the Electronic Reporting Tool 

(ERT) (see https://www.epa.gov/ 

electronic-reporting-air-emissions/ 

electronic-reporting-tool-ert). For any 

performance evaluations with no 

corresponding RATA pollutants listed 

on the ERT Web site, you must submit 

the results of the performance 

evaluation to the Administrator at the 

appropriate address listed in § 63.13. 

* * * * * 

(10) If the total continuous monitoring 

system downtime for any CEM or any 

CMS for the reporting period is 10 

percent or greater of the total operating 

time for the reporting period, the owner 

or operator shall submit an excess 

emissions and continuous monitoring 

system performance report along with 

the summary report. 

(c) Reporting a failure to meet a 

standard due to a malfunction. For each 

failure to meet a standard or emissions 

limit caused by a malfunction at an 

affected source, you must report the 

failure in the semi-annual compliance 

report required by § 63.1354(b)(9). The 

report must contain the date, time and 

duration, and the cause of each event 

(including unknown cause, if 

applicable), and a sum of the number of 

events in the reporting period. The 

report must list for each event the 

affected source or equipment, an 

estimate of the amount of each regulated 

pollutant emitted over the emission 

limit for which the source failed to meet 

a standard, and a description of the 

method used to estimate the emissions. 

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 § 63.1348(d), 

including actions taken to correct a 

malfunction. 

■ 8. Section 63.1355 is amended by 

revising paragraph (e) to read as follows: 

§ 63.1355 Recordkeeping requirements. 

* * * * * 

(e) You must keep records of the daily 

clinker production rates according to 

the clinker production monitoring 

requirements in § 63.1350(d). 

* * * * * 

■ 9. Table 1 to subpart LLL of part 63 

is amended by adding the entry 

‘‘63.10(e)(3)(v)’’ to read as follows: 


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Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules 44285 

TABLE 1 TO SUBPART LLL OF PART 63—APPLICABILITY OF GENERAL PROVISIONS

Citation Requirement Applies to subpart LLL Explanation 

*******

63.10(e)(3)(v) ................. Due Dates for Excess Emissions and CMS ..........

Performance Reports 

No .................................. § 63.1354(b)(9) specifies due date. 

* * * * * * * 

■ 10. Add table 2 to subpart LLL of part 

63 to read as follows: 

TABLE 2 TO SUBPART LLL OF PART 63—1989 TOXIC EQUIVALENCY FACTORS (TEFS) 

Dioxins/furans TEFs 1989 

2,3,7,8-TCDD ................................................................................................................................................................................. 1 

1,2,3,7,8-PeCDD ............................................................................................................................................................................ 0.5 

1,2,3,4,7,8-HxCDD ......................................................................................................................................................................... 0.1 

1,2,3,6,7,8-HxCDD ......................................................................................................................................................................... 0.1 

1,2,3,7,8,9-HxCDD ......................................................................................................................................................................... 0.1 

1,2,3,4,6,7,8-HpCDD ..................................................................................................................................................................... 0.01 

OCDD ............................................................................................................................................................................................ 0.001 

2,3,7,8-TCDF ................................................................................................................................................................................. 0.1 

1,2,3,7,8-PeCDF ............................................................................................................................................................................ 0.05 

2,3,4,7,8-PeCDF ............................................................................................................................................................................ 0.5 

1,2,3,4,7,8-HxCDF ......................................................................................................................................................................... 0.1 

1,2,3,6,7,8-HxCDF ......................................................................................................................................................................... 0.1 

1,2,3,7,8,9-HxCDF ......................................................................................................................................................................... 0.1 

2,3,4,6,7,8-HxCDF ......................................................................................................................................................................... 0.1 

1,2,3,4,6,7,8-HpCDF ...................................................................................................................................................................... 0.01 

1,2,3,4,7,8,9-HpCDF ...................................................................................................................................................................... 0.01 

OCDF ............................................................................................................................................................................................. 0.001 

[FR Doc. 2017–19448 Filed 9–20–17; 8:45 am] 

BILLING CODE 6560–50–P 


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