8392 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 63 

[EPA–HQ–OAR–2014–0830; FRL–9922–10– 

OAR] 

RIN 2060–AQ99 

National Emission Standards for 

Aerospace Manufacturing and Rework 

Facilities Risk and Technology Review 

AGENCY: Environmental Protection 

Agency. 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing amendments 

to the national emissions standards for 

hazardous air pollutants (NESHAP) for 

Aerospace Manufacturing and Rework 

Facilities to address the results of the 

residual risk and technology review 

(RTR) conducted as required under the 

Clean Air Act (CAA), and to correct 

errors and deficiencies identified during 

the review of these standards. The 

proposed amendments would add 

limitations to reduce organic and 

inorganic emissions of hazardous air 

pollutants (HAP) from specialty coating 

application operations; would remove 

the exemptions from the emission 

limitations for periods of startup, 

shutdown and malfunction (SSM) so 

that affected units would be subject to 

the emission standards at all times; and 

would revise provisions to address 

recordkeeping and reporting 

requirements applicable to periods of 

SSM. This action also proposes other 

technical corrections. The EPA 

estimates that implementation of this 

proposed rule will result in reductions 

of 58 tons of HAP. 

DATES: Comments. Comments must be 

received on or before April 3, 2015. A 

copy of comments on the information 

collection provisions should be 

submitted to the Office of Management 

and Budget (OMB) on or before March 

19, 2015. 

Public Hearing. If anyone contacts the 

EPA requesting a public hearing by 

February 23, 2015, we will hold a public 

hearing on March 4, 2015. If you are 

interested in requesting a public hearing 

or attending the public hearing, contact 

Ms. Pamela Garrett at (919) 541–7966 or 

at garrett.pamela@epa.gov. If the EPA 

holds a public hearing, the EPA will 

keep the record of the hearing open for 

30 days after completion of the hearing 

to provide an opportunity for 

submission of rebuttal and 

supplementary information. 

ADDRESSES: Comments. Submit your 

comments, identified by Docket ID No. 

EPA–HQ–OAR–2014–0830, by one of 

the following methods: 

• Federal eRulemaking Portal: http:// 

www.regulations.gov. Follow the online 

instructions for submitting comments. 

• Email: A-and-R-Docket@epa.gov. 

Include Attention Docket ID No. EPA– 

HQ–OAR–2014–0830 in the subject line 

of the message. 

• Fax: (202) 566–9744, Attention 

Docket ID No. EPA–HQ–OAR–2014– 

0830. 

• Mail: Environmental Protection 

Agency, EPA Docket Center (EPA/DC), 

Mail Code 28221T, Attention Docket ID 

No. EPA–HQ–OAR–2014–0830, 1200 

Pennsylvania Avenue NW., Washington, 

DC 20460. In addition, please mail a 

copy of your comments on the 

information collection provisions to the 

Office of Information and Regulatory 

Affairs, Office of Management and 

Budget (OMB), Attn: Desk Officer for 

EPA, 725 17th Street NW., Washington, 

DC 20503. 

• Hand/Courier Delivery: EPA Docket 

Center, Room 3334, EPA WJC West 

Building, 1301 Constitution Avenue 

NW., Washington, DC 20004, Attention 

Docket ID No. EPA–HQ–OAR–2014– 

0830. Such deliveries are only accepted 

during the Docket’s normal hours of 

operation, and special arrangements 

should be made for deliveries of boxed 

information. 

Instructions. Direct your comments to 

Docket ID No. EPA–HQ–OAR–2014– 

0830. 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 confidential 

business information (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 

viruses. For additional information 

about the EPA’s public docket, visit the 

EPA Docket Center homepage at: 

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

Docket. The EPA has established a 

docket for this rulemaking under Docket 

ID No. EPA–HQ–OAR–2014–0830. All 

documents in the docket are listed in 

the http://www.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. 

Public Hearing. If a public hearing is 

requested by February 23, 2015, it will 

be held on March 4, 2015 at the EPA’s 

Research Triangle Park Campus, 109 

T.W. Alexander Drive, Research 

Triangle Park, NC 27711. The hearing 

will convene at 10:00 a.m. (Eastern 

Standard Time) and end at 5:00 p.m. 

(Eastern Standard Time). A lunch break 

will be held from 12:00 p.m. (Eastern 

Standard Time) until 1:00 p.m. (Eastern 

Standard Time). Please contact Ms. 

Pamela Garrett at (919) 541–7966 or at 

garrett.pamela@epa.gov to request a 

hearing, to determine if a hearing will 

be held and to register to speak at the 

hearing, if one is held. If a hearing is 

requested, the last day to pre-register in 

advance to speak at the hearing will be 

March 2, 2015. 

Additionally, requests to speak will 

be taken the day of the hearing at the 

hearing registration desk, although 

preferences on speaking times may not 

be able to be fulfilled. If you require the 

service of a translator or special 

accommodations such as audio 

description, please let us know at the 

time of registration. If you require an 

accommodation, we ask that you 

preregister for the hearing, as we may 

not be able to arrange such 


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accommodations without advance 

notice. 

If no one contacts the EPA requesting 

a public hearing to be held concerning 

this proposed rule by February 23, 2015, 

a public hearing will not take place. If 

a hearing is held, it will provide 

interested parties the opportunity to 

present data, views or arguments 

concerning the proposed action. The 

EPA will make every effort to 

accommodate all speakers who arrive 

and register. Because the hearing will be 

held at a U.S. governmental facility, 

individuals planning to attend the 

hearing should be prepared to show 

valid picture identification to the 

security staff in order to gain access to 

the meeting room. Please note that the 

REAL ID Act, passed by Congress in 

2005, established new requirements for 

entering federal facilities. If your 

driver’s license is issued by Alaska, 

American Samoa, Arizona, Kentucky, 

Louisiana, Maine, Massachusetts, 

Minnesota, Montana, New York, 

Oklahoma or the state of Washington, 

you must present an additional form of 

identification to enter the federal 

building. Acceptable alternative forms 

of identification include: federal 

employee badges, passports, enhanced 

driver’s licenses and military 

identification cards. In addition, you 

will need to obtain a property pass for 

any personal belongings you bring with 

you. Upon leaving the building, you 

will be required to return this property 

pass to the security desk. No large signs 

will be allowed in the building, cameras 

may only be used outside of the 

building and demonstrations will not be 

allowed on federal property for security 

reasons. 

The EPA may ask clarifying questions 

during the oral presentations, but will 

not respond to the presentations at that 

time. Written statements and supporting 

information submitted during the 

comment period will be considered 

with the same weight as oral comments 

and supporting information presented at 

the public hearing. Commenters should 

notify Ms. Garrett if they will need 

specific equipment, or if there are other 

special needs related to providing 

comments at the hearing. Verbatim 

transcripts of the hearings and written 

statements will be included in the 

docket for the rulemaking. The EPA will 

make every effort to follow the schedule 

as closely as possible on the day of the 

hearing; however, please plan for the 

hearing to run either ahead of schedule 

or behind schedule. Again, a hearing 

will not be held unless requested. 

FOR FURTHER INFORMATION CONTACT: For 

questions about this proposed action, 

contact Kim Teal, Sector Policies and 

Programs Division (D243–02), Office of 

Air Quality Planning and Standards, 

U.S. Environmental Protection Agency, 

Research Triangle Park, North Carolina 

27711; telephone number: (919) 541– 

5580; fax number: (919) 541–5450; and 

email address: teal.kim@epa.gov. For 

specific information regarding the risk 

modeling methodology, contact Ted 

Palma, 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– 

5470; fax number: (919) 541–0840; and 

email address: palma.ted@epa.gov. For 

information about the applicability of 

the NESHAP to a particular entity, 

contact Rafael Sanchez, Office of 

Enforcement and Compliance Assurance 

(OECA), (202) 564–7028, 

sanchez.rafael@epa.gov. 

SUPPLEMENTARY INFORMATION: 

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: 

AD Airworthiness Directive 

AEGL acute exposure guideline level 

AERMOD air dispersion model used by the 

HEM–3 model 

ATSDR Agency for Toxic Substances and 

Disease Registry 

BACT Best Achievable Control Technology 

CAA Clean Air Act 

CalEPA California EPA 

CBI Confidential Business Information 

CDX EPA’s Central Data Exchange 

CEDRI EPA’s Compliance and Emissions 

Data Reporting Interface 

CFR Code of Federal Regulations 

CTG Control Technique Guideline 

document 

EJ environmental justice 

EPA Environmental Protection Agency 

ERPG Emergency Response Planning 

Guidelines 

ERT EPA’s Electronic Reporting Tool 

FAA Federal Aviation Administration 

FR Federal Register 

g/L grams/liter 

HAP hazardous air pollutants 

HCl hydrochloric acid 

HEM–3 Human Exposure Model, Version 

1.1.0 

HF hydrogen fluoride 

HI hazard index 

HQ hazard quotient 

HVLP high volume low pressure 

IARC International Agency for Research on 

Cancer 

ICR information collection request 

IRIS Integrated Risk Information System 

km kilometer 

lb/gal pounds/gallon 

LOAEL Lowest-observed-adverse-effect 

level 

MACT maximum achievable control 

technology 

mg/m3 milligrams per cubic meter 

MIR maximum individual risk 

mm Hg millimeters mercury 

NAAQS National Ambient Air Quality 

Standards 

NAICS North American Industry 

Classification System 

NAS National Academy of Sciences 

NATA National Air Toxics Assessment 

NEI National Emission Inventory 

NESHAP National Emissions Standards for 

Hazardous Air Pollutants 

NOAA National Oceanic and Atmospheric 

Administration 

NOAEL No-observed-adverse-effect levels 

NRC National Research Council 

NRDC Natural Resources Defense Council 

NTP National Toxicology Program 

NTTAA National Technology Transfer and 

Advancement Act 

OAQPS Office of Air Quality Planning and 

Standards 

OECA Office of Enforcement and 

Compliance Assurance 

OEM original equipment manufacturer 

OMB Office of Management and Budget 

PAH polycyclic aromatic hydrocarbons 

PB–HAP hazardous air pollutants known to 

be persistent and bio-accumulative in the 

environment 

PEL Probable effect level 

POM polycyclic organic matter 

ppm parts per million 

PSD Prevention of Significant Deterioration 

RACT Reasonably Available Control 

Technology 

RBLC EPA’s RACT/BACT/LAER 

Clearinghouse 

RCRA Resource Conservation and Recovery 

Act of 1976 

REL reference exposure level 

RFA Regulatory Flexibility Act 

RfC reference concentration 

RfD reference dose 

RoC Report of the Carcinogens 

RTR residual risk and technology review 

SAB Science Advisory Board 

SCAQMD South Coast Air Quality 

Management District 

SSM startup, shutdown and malfunction 

TOSHI target organ-specific hazard index 

tpy tons per year 

TRIM.FaTE Total Risk Integrated 

Methodology.Fate, Transport, and 

Ecological Exposure model 

TTN Technology Transfer Network 

UF uncertainty factor 

mg/m3 microgram per cubic meter 

UMRA Unfunded Mandates Reform Act 

URE unit risk estimate 

VOC volatile organic compounds 

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? 


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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? 

E. What litigation is related to this 

proposed action? 

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 actions are we taking pursuant to 

CAA sections 112(d)(2) and 112(d)(3)? 

B. What are the results of the risk 

assessment and analyses? 

C. What are our proposed decisions 

regarding risk acceptability, ample 

margin of safety and adverse 

environmental effects? 

D. What are the results and proposed 

decisions based on our technology 

review? 

E. What other actions are we proposing? 

F. What compliance dates are we 

proposing? 

V. Summary of Cost, Environmental and 

Economic Impacts 

A. What are the 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. Paperwork Reduction Act 

C. Regulatory Flexibility Act (RFA) 

D. Unfunded Mandates Reform Act 

(UMRA) 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination with Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children from Environmental Health 

Risks and Safety Risks 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution or Use 

I. National Technology Transfer and 

Advancement Act (NTTAA) 

J. 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 

regulated industrial source category that 

is the subject of this proposal. Table 1 

is not intended to be exhaustive, but 

rather to provide 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 government entities 

may be affected by this proposed action. 

Parties potentially affected by this 

action include major and synthetic 

minor source installations that are 

owned or operated by the Armed Forces 

of the United States (including the 

Department of Defense and the Coast 

Guard) and the National Aeronautics 

and Space Administration. As defined 

under the ‘‘Surface Coating’’ industry 

sector 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 

Aerospace Manufacturing and Rework 

Facilities source category is any facility 

engaged, either in part or in whole, in 

the manufacture or rework of 

commercial, civil or military aerospace 

vehicles or components and that are 

major sources as defined in 40 CFR 63.2. 

TABLE 1—INDUSTRIAL SOURCE CATEGORY AFFECTED BY THIS PROPOSED ACTION

Source Category NESHAP NAICS code a

Aerospace Manufacturing and Rework Facilities Aerospace Manufacturing and Rework Facilities.336411, 336412, 336413, 336414, 336415, 

336419, 481111, 481112, 481211, 481212, 

481219. 

a North American Industry Classification System. 

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 through the 

EPA’s Technology Transfer Network 

(TTN) Web site, a forum for information 

and technology exchange in various 

areas of air pollution control. Following 

signature by the EPA Administrator, the 

EPA will post a copy of this proposed 

action at: http://www.epa.gov/ttn/atw/

aerosp/aeropg.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 residual 

risk and technology review program is 

available at the following Web site: 

http://www.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–2014–0830. 

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 


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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) through (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) and (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). CAA Section 112(f)(1) 

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. 

CAA section 112(f)(2) 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 the emission standards 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 upheld as reasonable the EPA’s 

interpretation that subsection 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 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 


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8396 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / 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. See CAA section 

112(a)(7). 

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 

CAA section 112(f)(2) 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 

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 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 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. 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 8397 

2 Guideline Series: Control of Volatile Organic 

Compound Emissions from Coating Operations at 

Aerospace Manufacturing and Rework Operations. 

Emission Standards Division, U. S. Environmental 

Protection Agency, Office of Air and Radiation, 

Office of Air Quality Planning and Standards, 

Research Triangle Park, NC 27711, December 1997. 

Publication No. EPA–453/R–97–004. 

B. What is this source category and how 

does the current NESHAP regulate its 

HAP emissions? 

1. Description of the Aerospace 

Manufacturing and Rework Facilities 

Source Category and Applicability. 

The NESHAP for the Aerospace 

Manufacturing and Rework Facilities 

source category (henceforth referred to 

as the ‘‘Aerospace NESHAP’’) was 

promulgated on September 1, 1995 (60 

FR 45956) and codified at 40 CFR part 

63, subpart GG. As promulgated in 

1995, the Aerospace NESHAP applies to 

the surface coating and related 

operations at each new and existing 

affected source of HAP emissions at 

facilities that are major sources and are 

engaged, either in part or in whole, in 

the manufacture or rework of 

commercial, civil or military aerospace 

vehicles or components. The 

requirements of the standards are nearly 

the same for both new and existing 

sources. The Aerospace NESHAP (40 

CFR 63.742) defines ‘‘aerospace vehicle 

or component’’ as ‘‘any fabricated part, 

processed part, assembly of parts or 

completed unit, with the exception of 

electronic components, of any aircraft, 

including, but not limited to airplanes, 

helicopters, missiles, rockets, and space 

vehicles.’’ Today, we estimate that 144 

facilities are subject to the Aerospace 

NESHAP. A complete list of facilities 

subject to the Aerospace NESHAP is 

available in the Aerospace RTR 

database, which is available for review 

in the docket for this proposed 

rulemaking. Section 63.741(c) defines 

each affected source in the Aerospace 

Manufacturing and Rework Facilities 

source category, and a facility could 

have a combination of both new and 

existing affected sources. However, the 

emission standards for new and existing 

affected sources are the same for nearly 

all operations within subpart GG. The 

exceptions are the filter efficiency 

requirements to control inorganic HAP 

emissions from primer and topcoat 

spray application operations in 40 CFR 

63.745 and for dry media blasting 

operations in 40 CFR 63.746 and the 

requirements for controls to reduce 

organic HAP emissions from chemical 

depainting operations in 40 CFR 

63.746(c). 

The Aerospace NESHAP applies to 

organic HAP emissions from cleaning 

operations, depainting operations, 

primer application operations, topcoat 

application operations, chemical milling 

maskant application operations and the 

handling and storage of waste. The rule 

also applies to inorganic HAP emissions 

from primer and topcoat application 

operations using spray equipment and 

depainting operations using dry media 

blasting. The rule provides an 

exemption for primers, topcoats and 

chemical milling maskants used in lowvolumes which is defined as 189 liters 

(50 gallons) or less per formulation and 

for which the combined annual total 

does not exceed 757 liters (200 gallons). 

The current Aerospace NESHAP 

explicitly excludes specialty coatings 

from meeting any control requirements, 

as specified in 40 CFR 63.741(f) and in 

40 CFR 63.742 (i.e., the definitions for 

‘‘exterior primer,’’ ‘‘primer,’’ and 

‘‘topcoat’’). Appendix A of the 

Aerospace NESHAP defines 59 separate 

categories of specialty coatings. 

Although the EPA did not include 

emission limitations for specialty 

coatings in the Aerospace NESHAP 

finalized in 1995 or in any subsequent 

amendments, the EPA included VOC 

content limits for the 59 categories of 

specialty coatings in the 1997 Aerospace 

Control Techniques Guidelines (CTG) 

document.2 The CAA requires that state 

implementation plans (SIPs) for certain 

ozone nonattainment areas be revised to 

require the implementation of 

reasonably available control technology 

(RACT) to control volatile organic 

compounds (VOC) emissions. The EPA 

has defined RACT as the lowest 

emission limitation that a particular 

source is capable of meeting by the 

application of control technology that is 

reasonably available considering 

technological and economic feasibility. 

The Aerospace CTG is intended to 

provide state and local air pollution 

control authorities with an information 

base, recommended emissions 

limitations and monitoring, 

recordkeeping and reporting 

requirements for proceeding with their 

analyses of reasonably available control 

technology (RACT) for their own 

regulations to reduce VOC emissions 

from aerospace surface coating 

operations. 

2. Organic and Inorganic HAP Emission 

Sources 

Organic HAP emissions from cleaning 

and depainting operations occur from 

the evaporation of the volatile portion of 

the cleaning solvents or chemical 

strippers. Cleaning emissions are 

typically fugitive in nature and occur at 

most processing steps. Emissions from 

depainting operations that occur within 

a booth or hangar are typically captured 

and exhausted through a stack, although 

some emissions may be fugitive in 

nature (e.g., open tanks). 

Organic HAP emissions from coating 

(primers, topcoats and chemical milling 

maskants) application operations occur 

from the evaporation of the solvent 

contained in the coatings. These 

emissions occur during the application 

of the coatings on aerospace vehicles or 

parts, which may take place in large 

open areas, such as hangars or in 

partially or fully enclosed spaces, such 

as within spray booths. 

Organic HAP emissions from waste 

occur from evaporation of the volatile 

portion of the waste while it is being 

handled or stored. These emissions are 

fugitive in nature, occurring from each 

waste container. 

Some coatings contain compounds 

that are inorganic HAP. Inorganic HAP 

emissions from coatings occur during 

the application of the coating if it is 

applied using spray guns. These 

inorganic HAP emissions are paint 

particulates, commonly referred to as 

‘‘overspray,’’ that do not adhere to the 

surface being coated. Like the organic 

HAP emissions from the operations, the 

emissions of the inorganic HAP may 

occur in large open areas, such as 

hangars or in partially or fully enclosed 

spaces, such as within spray booths. 

However, coatings that contain 

inorganic HAP are typically applied in 

spray booths equipped with exhaust 

filters to capture paint overspray. 

Inorganic HAP are not emitted from 

coatings applied with non-spray 

methods, such as brushes, rollers or dip 

coating, because the coating is not 

atomized with these methods. 

Inorganic HAP emissions from 

depainting operations may occur from 

non-chemical methods, such as plastic 

and other types of dry media blasting, 

used to strip an aerospace vehicle. 

(Chemical stripping techniques do not 

release inorganic HAP.) These emissions 

occur as particulates generated during 

the blasting process. The operation is 

typically carried out within a large 

hangar equipped with a ventilation 

system and particulate filtration device 

(e.g., a baghouse) or in smaller 

enclosures, also equipped with 

filtration. The inorganic HAP that are 

released from the depainting operations 

are primarily found in the paint being 

stripped, although some stripping media 

may contain trace amounts of inorganic 

HAP. 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
8398 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

3. Regulation of Organic and Inorganic 

HAP Emissions in the Aerospace 

NESHAP 

The Aerospace NESHAP specifies 

numerical emission limits for organic 

HAP emissions from primer, topcoat, 

chemical milling maskant application 

operations and chemical depainting 

operations; equipment and filter 

efficiency requirements for dry media 

blasting depainting operations and 

spray applied coating operations; 

composition requirements and 

equipment standards for cleaning 

operations; and work practice standards 

for waste handling and storage 

operations. 

The organic HAP emission rate for 

primers is 540 grams/liter (g/L) (4.5 

pounds/gallon (lb/gal)) (less water) for 

general aviation rework facilities; 650 g/ 

L (5.4 lb/gal) (less water) for large 

commercial aircraft; or 350 g/L (2.9 lb/ 

gal) for other primers (40 CFR 

63.745(c)(1) and (2)). For topcoats and 

self-priming topcoats the emission rate 

is 420 g/L (3.5 lb/gal) (less water); and 

540 g/L (4.5 lb/gal) (less water) for 

primers and self-priming topcoats at 

general aviation rework facilities (40 

CFR 63.745(c)(3) and (4)). Alternatively, 

a control system can be used to capture 

and control emissions from the primer 

or topcoat application operation (40 

CFR 63.745(d)). The system must 

achieve an overall control efficiency of 

81 percent. Further, the Aerospace 

NESHAP specifies which types of 

coating application techniques may be 

used (40 CFR 63.745(f)). The Aerospace 

NESHAP also provides operating 

requirements for the application of 

primers or topcoats that contain 

inorganic HAP, including control of 

spray booth exhaust streams with either 

particulate filters or waterwash systems 

(40 CFR 63.745(g)). The primer and 

topcoat limits and control requirements 

do not apply to specialty coatings 

defined in Appendix A to subpart GG. 

The organic HAP emission content 

limits for chemical milling maskants for 

use with Type I chemical milling 

solutions is 622 g/L (5.2 lb/gal) (less 

water) and 160 g/L (1.3 lb/gal) (less 

water) for use with Type II chemical 

milling solutions (40 CFR 63.747(c)). 

Alternatively, a control system that 

achieves an overall control efficiency of 

81 percent can be used to capture and 

control emissions from the maskant 

application operation (40 CFR 

63.747(d)). These requirements do not 

apply to touch-up of scratched surfaces 

or damaged maskant and touch-up of 

trimmed edges. 

For cleaning operations (including 

hand-wipe cleaning), the Aerospace 

NESHAP specifies that cleaning 

solvents meet certain composition 

requirements or that the cleaning 

solvents have a composite vapor 

pressure of no more than 45 millimeters 

mercury (mm Hg) (24.1 in. water) (40 

CFR 63.744(b)). Work practice measures 

are also required (40 CFR 63.744(a)). 

Four work practice alternative 

techniques are specified for spray gun 

cleaning, and work practice standards 

are specified for flush cleaning 

operations (40 CFR 63.744(c) and (d)). 

The Aerospace NESHAP also specifies 

requirements for depainting operations. 

Where there are no controls for organic 

HAP emissions from chemical 

depainting operations, the rule prohibits 

organic HAP emissions from chemical 

depainting operations, with the 

exception that 26 gallons of HAPcontaining chemical stripper (or 

alternatively 190 pounds of organic 

HAP) may be used for each commercial 

aircraft stripped, or 50 gallons (or 365 

pounds of organic HAP) for each 

military aircraft for spot stripping and 

decal removal (40 CFR 63.746(b)(1) 

through (3)). Where there are controls 

for organic HAP emissions from 

chemical depainting, emissions must be 

reduced by 81 percent for controls 

installed before the effective date, and 

by 95 percent for controls installed on 

or after the effective date (40 CFR 

63.746(c)). For non-chemical depainting 

operations that generate inorganic HAP 

emissions from dry media blasting, the 

operation must be performed in an 

enclosed area or in a closed cycle 

depainting system and the air stream 

from the operation must pass through a 

dry filter system meeting a minimum 

efficiency specified in the rule, through 

a baghouse or through a waterwash 

system before being released to the 

atmosphere (40 CFR 63.746(b)(4)). 

The handling and storage of waste 

that contains HAP must be conducted in 

a manner that minimizes spills (40 CFR 

63.748). 

C. What data collection activities were 

conducted to support this action? 

In February 2011, the EPA issued an 

information collection request (ICR), 

pursuant to CAA section 114, to 

approximately 1,300 facilities that were 

thought to potentially own and operate 

Aerospace Manufacturing and Rework 

Facilities. Information was requested on 

operations subject to the Aerospace 

NESHAP (coatings, blast depainting 

operations, solvent depainting 

operations and solvent cleaning 

operations) as well as specialty coatings, 

chemical milling and metal finishing 

operations, composite processing, 

storage tanks and wastewater treatment. 

Information was also requested on booth 

characteristics and control devices and 

location coordinates (latitude and 

longitude) of emission stacks and 

operations. The ICR requested available 

information regarding coating and 

solvent usage, process equipment, 

control devices used, point and fugitive 

HAP emissions, practices used to 

control HAP emissions and other 

aspects of facility operations. A total of 

87 major source facilities and 57 

synthetic minor facilities responded to 

the survey and were included in the risk 

modeling analysis. The remaining 

facilities were either area source 

facilities, not aerospace manufacturing 

or rework facilities or closed facilities, 

or the ICR was returned undeliverable. 

We received data on coating and solvent 

usage, chemical milling, metal finishing, 

depainting operations, composite 

processing operations, storage tanks, 

wastewater treatment operations and 

use of add-on control devices. From 

these data, we were able to calculate 

HAP emissions for each of the major 

source and synthetic minor facilities 

that responded to the survey. 

In October 2012, the EPA issued a 

request for stack test data under the 

authority of section 114 of the CAA. 

This request was sent to 9 parent 

companies for 18 facilities, requesting 

stack emissions testing data for selected 

coating operations and spray booths and 

blast depainting, composite processing 

and metal finishing operations believed 

to represent the various processes and 

capture and control configurations used 

by the industry. All facilities either 

responded to the survey or provided 

information indicating the operations 

for which we requested stack testing 

had been shutdown. 

In September 2013, the EPA issued an 

additional request to the same 

companies requesting supplemental 

testing to confirm the content of the 

coatings used in the October 2012 stack 

testing. These data were used to speciate 

emissions for individual coatings and to 

develop the default chromium 

speciation profile for processes included 

in the 2011 ICR. 

In May 2014, the EPA solicited 

industry review of the EPA’s draft 

modeling file records (e.g., estimated 

emissions and emission estimation 

methods) that were developed based on 

the results of the data collection efforts 

described above and the 2011 National 

Emission Inventory (NEI) and 2005 

National Air Toxics Assessment (NATA) 

discussed in section II.D of this 

preamble. Of the 171 facilities 

contacted, 84 facilities responded. Of 

the 171 facilities contacted, the EPA 

determined that 144 are in operation 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 8399 

3Sierra Club v. EPA, 479 F. 3d 875 (D.C. Cir. 

March 13, 2007). 

4Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 

2008), cert. denied, 130 S. Ct 1735 (2010). 

5U.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. 

and subject to the NESHAP and 27 

facilities are closed or not subject to the 

Aerospace NESHAP (e.g., are area 

sources). The 144 facilities that were 

determined to be in operation and 

subject to the NESHAP are included in 

the model input file for the risk 

assessment. 

D. What other relevant background 

information and data are available? 

The 2011 NEI provided supplemental 

information for this RTR. The NEI is a 

database that contains information 

about sources that emit criteria air 

pollutants, their precursors and HAP. 

The database includes estimates of 

annual air pollutant emissions from 

point, nonpoint and mobile sources in 

the 50 states, the District of Columbia, 

Puerto Rico and the Virgin Islands. The 

EPA collects this information and 

releases an updated version of the NEI 

database every 3 years. The NEI 

includes information necessary for 

conducting risk modeling, including 

annual HAP emissions estimates from 

individual emission points at facilities 

and the related emissions release 

parameters. For each emission record 

that was needed for the model input file 

for the risk assessment (hereafter 

referred to as the ‘‘RTR emissions 

dataset’’) that was not available from the 

2011 ICR responses, the EPA used 

available data in the 2011 NEI as the 

first alternative. The NEI emission 

records used included annual HAP 

emissions estimates for boilers, engines, 

chemical manufacturing processes, 

secondary metal production processes, 

heaters, soil remediation, transportation 

equipment, waste disposal, welding and 

other miscellaneous manufacturing 

processes that were not included in the 

2011 ICR. Individual chromium 

emissions estimates were excluded from 

the modeling file if they were found to 

overlap with a regulated process. 

The 2005 NATA also provided 

supplemental data for the RTR 

emissions dataset for this RTR. The 

2005 NATA includes annual HAP 

emissions estimates for three Aerospace 

Manufacturing and Rework Facilities 

that are not in the 2011 NEI. These data 

were incorporated into the RTR 

emissions dataset, and include emission 

data for space heaters, boilers and 

underground fuel tanks at the facilities. 

Although the 2005 NATA data is 

outdated, we thought it important to 

ensure we had accounted for all the 

major sources in the source category and 

given that we did not have data on three 

of the facilities, EPA augmented our 

RTR emissions dataset with this data for 

three of the 144 facilities. We expect to 

have updated NATA soon and will 

consider the impact on the three 

sources, as appropriate. NATA is the 

EPA’s ongoing evaluation of air toxics in 

the United States. The EPA developed 

NATA as a screening tool for state/local/ 

tribal agencies to prioritize pollutants, 

emission sources and locations of 

interest for further study in order to gain 

a better understanding of population 

risks. NATA assessments do not 

incorporate refined information about 

emission sources, but rather use general 

information about sources to develop 

estimates of risks which are more likely 

to overestimate impacts than 

underestimate them. NATA provides 

estimates of the risk of cancer and other 

serious health effects from breathing 

(inhaling) air toxics in order to inform 

both national and more localized efforts 

to identify and prioritize air toxics, 

emission source types and locations 

which are of greatest potential concern 

in terms of contributing to population 

risk. 

E. What litigation is related to this 

proposed action? 

In 2007, the United States Court of 

Appeals for the District of Columbia 

Circuit found that the EPA had erred in 

establishing emissions standards for 

sources of HAP in the NESHAP for 

Brick and Structural Clay Products 

Manufacturing and Clay Ceramics 

Manufacturing, 67 FR 26690 (May 16, 

2003), and consequently vacated the 

rules.3 Among other things, the court 

found EPA erred by failing to regulate 

processes that emitted HAP, in some 

instances by establishing a MACT floor 

of ‘‘no control.’’ In this action we are 

proposing to correct the same error in 

the Aerospace NESHAP by proposing to 

remove the exemption for specialty 

coatings found at 40 CFR 63.741(f) and 

instead add limits for specialty coatings 

(including adhesives, adhesive bonding 

primers and sealants). 

In a separate case, the court vacated 

portions of two provisions in the EPA’s 

CAA section 112 regulations that govern 

emissions of HAP during periods of 

SSM.4 Specifically, the court vacated 

the SSM exemption contained in 40 

CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), 

holding that under section 302(k) of the 

CAA, emissions standards or limitations 

must be continuous in nature and that 

the SSM exemption violates the CAA’s 

requirement that some section 112 

standards apply continuously. In this 

action, we are also proposing to revise 

these provisions for Aerospace 

Manufacturing and Rework Facilities 

operations, as discussed in section 

IV.E.2 of this preamble. 

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. 

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 

seven sections that follow this 

paragraph describe how we estimated 

emissions and conducted the risk 

assessment. The docket for this 

rulemaking contains the following 

document that provides more 

information on the risk assessment 

inputs and models: Residual Risk 

Assessment for the Aerospace 

Manufacturing and Rework Facilities 

Source Category in Support of the 

January, 2015 Risk and Technology 

Review Proposal, January 2015. The 

methods used to assess risks (as 

described in the 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;5 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? 

Data for 144 Aerospace Manufacturing 

and Rework Facilities were used to 

create the RTR emissions dataset, as 

described in section II.C of this 

preamble. The emissions sources 

included in the RTR emissions dataset 

includes the following types of sources 

currently regulated by the Aerospace 

NESHAP: Primer/topcoat application 

operations, waste handling operations, 

chemical milling maskant application 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
8400 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

6This metric comes from the Benzene NESHAP. 

See 54 FR 38046. 

7U.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). 

8A census block is the smallest geographic area 

for which census statistics are tabulated. 

operations, cleaning operations and 

chemical and blast depainting 

operations. The RTR emissions dataset 

also includes the following types of 

sources not currently regulated by the 

Aerospace NESHAP: Specialty coatings, 

composite processing, chemical milling 

and metal finishing, wastewater, storage 

tanks, boilers, engines, chemical 

manufacturing processes, secondary 

metal production processes, heaters, soil 

remediation, transportation equipment, 

waste disposal, welding and other 

miscellaneous manufacturing processes. 

These emission sources include both 

fugitive emissions and stack emissions. 

This RTR emissions dataset is based 

primarily on data gathered through the 

CAA section 114 questionnaire, as 

described in section II.C of this 

preamble. This dataset was 

supplemented with data received from 

the 2012 ICR for stack testing data and 

the 2013 request for information on 

coatings analyses (as described in 

section II.C of this preamble), the 2011 

NEI (as described in section II.D of this 

preamble) and the 2005 NATA (as 

described in section II.D of this 

preamble). The sources noted above 

provided all of the emissions data in the 

RTR emissions dataset and nearly all of 

the facility specific data needed to 

conduct the risk modeling analysis. 

However, there were limited instances 

where default values were used to fill 

gaps in the facility-specific data used in 

the risk modeling analysis. Examples of 

default values used to fill these data 

gaps were default values used for stack 

height and other release point 

parameters, and percentages used to 

segregate mercury and chromium 

compounds into separate species. Use of 

defaults is discussed in detail in the 

memorandum, Aerospace 

Manufacturing and Rework Facilities 

RTR Modeling File Preparation, 

December 2014, available in the docket 

for this action (Modeling File 

Preparation Memo). 

The RTR emissions dataset was 

refined following an extensive quality 

assurance check of source locations, 

emission release characteristics and 

annual emission estimates. We checked 

the coordinates of each emission source 

in the dataset using ArcGIS to ensure 

the emission point locations were 

correct. Also, as discussed in section 

II.C of this preamble, in May 2014, the 

EPA solicited industry review of the 

dataset and made corrections, as 

needed. For further information on the 

EPA’s quality assurance review, see the 

Modeling File Preparation Memo 

available in the docket for this action. 

A list of the 144 facilities and 

additional information used to develop 

the RTR emissions dataset is available 

in the Aerospace RTR database, and 

documentation on the development of 

this database is provided in the 

Modeling File Preparation Memo, both 

of which are available in the docket for 

this action. 

2. How did we estimate MACTallowable emissions? 

The available emissions data in the 

RTR emissions dataset include estimates 

of the actual 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 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 residual risk rule (70 FR 

19998–19999, April 15, 2005) and in the 

proposed and final Hazardous Organic 

NESHAP residual risk rules (71 FR 

34428, June 14, 2006 and 71 FR 76609, 

December 21, 2006, respectively). In 

those previous actions, we noted that 

assessing the risks at the 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.) 

We used the RTR emissions dataset 

discussed in section III.A.1 of this 

preamble to estimate MACT-allowable 

emissions levels. Facilities were asked 

to provide a multiplier in the 2011 ICR 

survey to scale up average hourly 

emissions to maximum hourly 

emissions for air dispersion modeling, 

given that each facility typically has a 

large number of emission points and it 

would be difficult to determine the 

maximum hourly emissions from each 

emission point. Many of the facilities 

reported multipliers that were based on, 

for example, scaling production from 

2,000 hours to 8,760 hours per year or 

from one shift per day to three shifts. 

However, using these values would 

have led to unrealistically high 

‘‘allowable’’ emission values because of 

limitations in the market for new 

aerospace vehicles and for rework 

services, and because many facilities 

have permit restrictions on their total 

annual emissions. Therefore, the EPA 

did not use maximum hourly emissions 

and instead chose to use a multiplier 

based on current and historical industry 

capacity utilization factors. The EPA 

chose to use a single multiplier of 1.02 

to scale average annual emissions to 

allowable annual emissions. The 

allowable emissions multiplier is based 

on the difference between 2008 

production utilization rate of 83.1 

percent and the 20-year historical 

maximum production utilization rate 

from 1990 of 85.0 percent (85 ÷ 83.1 = 

1.02). The docket for this rulemaking 

contains information on the 

development of estimated MACTallowable emissions in the Modeling 

File Preparation Memo. 

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 

version 1.1.0). 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 6 and (3) estimating individual 

and population-level inhalation risks 

using the exposure estimates and 

quantitative dose-response information. 

The air dispersion model used in the 

analysis, the AERMOD model, is one of 

the EPA’s preferred models for assessing 

pollutant concentrations from industrial 

facilities.7 To perform the dispersion 

modeling and to develop the 

preliminary risk estimates, HEM–3 

draws on three data libraries. The first 

is a library of meteorological data, 

which is used for dispersion 

calculations. This library includes 1 

year (2011) of hourly surface and upper 

air observations for more than 800 

meteorological stations, selected to 

provide coverage of the United States 

and Puerto Rico. A second library of 

United States Census Bureau census 

block 8 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 


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9These classifications also coincide with the 

terms ‘‘known carcinogen, probable carcinogen, and 

possible carcinogen,’’ respectively, which are the 

terms advocated in the EPA’s previous Guidelines 

for Carcinogen Risk Assessment, published in 1986 

(51 FR 33992, September 24, 1986). Summing the 

risks of these individual compounds to obtain the 

cumulative cancer risks is an approach that was 

recommended by the EPA’s SAB in their 2002 peer 

review of EPA’s NATA entitled, NATA—Evaluating 

the National-scale Air Toxics Assessment 1996 

Data—an SAB Advisory, available at: http://

yosemite.epa.gov/sab/sabproduct.nsf/

214C6E915BB04E14852570CA007A682C/$File/

ecadv02001.pdf. 

10The SAB peer review of RTR Risk Assessment 

Methodologies is available at: http://

yosemite.epa.gov/sab/sabproduct.nsf/

4AB3966E263D943A8525771F00668381/$File/EPASAB-10-007-unsigned.pdf. 

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: http://www.epa.gov/ttn/ 

atw/toxsource/summary.html and are 

discussed in more detail later in this 

section. 

In developing the risk assessment for 

chronic exposures, we used the 

estimated annual average ambient air 

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 9) 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) 

(http://www.epa.gov/riskassessment/

glossary.htm), 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) Minimum 

Risk Level (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://www.oehha.ca.gov/air/hot_

spots/pdf/HRAguidefinal.pdf), which is 

defined as ‘‘the concentration level (that 

is expressed in units of micrograms per 

cubic meter (mg/m3) for inhalation 

exposure and in a dose expressed in 

units of milligram per kilogram-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.10 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 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 for 

our acute analysis. 


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8402 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

11National Academy of Sciences (NAS), 2001. 

Standing Operating Procedures for Developing 

Acute Exposure Levels for Hazardous Chemicals, 

page 2. 

12ERP Committee Procedures and 

Responsibilities. November 1, 2006. American 

Industrial Hygiene Association. 

13See http://www.tceq.state.tx.us/compliance/

field_ops/eer/index.html or the docket to access the 

source of these data. 

As described in the CalEPA’s Air 

Toxics Hot Spots Program Risk 

Assessment Guidelines, Part I, The 

Determination of Acute Reference 

Exposure Levels for Airborne Toxicants, 

an acute REL value (http://

www.oehha.ca.gov/air/pdf/acuterel.pdf) 

is defined as ‘‘the concentration level at 

or below which no adverse health 

effects are anticipated for a specified 

exposure duration.’’ Id. at page 2. Acute 

REL values are based on the most 

sensitive, relevant, adverse health effect 

reported in the peer-reviewed 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). As 

described in Standing Operating 

Procedures (SOP) of the National 

Advisory Committee on Acute Exposure 

Guideline Levels for Hazardous 

Substances (http://www.epa.gov/oppt/

aegl/pubs/sop.pdf),11 ‘‘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 Committee document titled, 

ERPGS Procedures and Responsibilities 

(http://sp4m.aiha.org/insideaiha/ 

GuidelineDevelopment/ERPG/

Documents/ERP-SOPs2006.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.’’ 12 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 

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 9.13

Considering this analysis, to account for 

more than 99 percent of the peak hourly 


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Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 8403 

14The SAB peer review of RTR Risk Assessment 

Methodologies is available at: http://

yosemite.epa.gov/sab/sabproduct.nsf/

4AB3966E263D943A8525771F00668381/$File/EPASAB-10-007-unsigned.pdf. 

15U.S. EPA. (2009) 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, and available 

online at http://cfpub.epa.gov/ncea/cfm/

recordisplay.cfm?deid=211003. 

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. 

However, we use a factor other than 10 

if we have information that indicates 

that a different factor is appropriate for 

a particular source category. 

For this source category, the default 

value was not utilized. A peak 1-hour 

emission multiplier of 1.2 times the 

annual emissions was utilized for the 

entire source category. This value was 

developed from current and historical 

industry capacity utilization factors. 

The emissions from this category are 

generally dependent on the amount of 

HAP in the coatings and the amount of 

coating applied, and would only vary in 

a significant manner if production 

increased. Therefore, the EPA based the 

acute emissions multiplier on potential 

changes in production. The acute 

emissions multiplier is based on the 

difference between 2008 production 

utilization rate of 83.1 percent and the 

maximum production utilization rate of 

100 percent, which has not been 

realized in 20 years of historical data 

(100 ÷ 83.1 = 1.2). The docket for this 

rulemaking contains information on the 

development of estimated MACT-acute 

emissions in the Modeling File 

Preparation Memo. A further discussion 

of why this factor was chosen can be 

found in Appendix 1 of the Modeling 

File Preparation Memo, 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 were less 

than or equal to 1 (even under the 

conservative assumptions of the 

screening analysis), acute impacts were 

deemed negligible and no further 

analysis was performed. In cases where 

an acute HQ from the screening step 

was greater than 1, additional sitespecific data were considered to 

develop a more refined estimate of the 

potential for acute impacts of concern. 

For this source category, the data 

refinements employed consisted of 

evaluating the off-site extent of any 

exceedances of the acute health 

benchmarks. These refinements are 

discussed more fully in the Modeling 

File Preparation Memo, which is 

available in the docket for this source 

category. 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 peer review of the EPA’s RTR 

risk assessment methodologies,14 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 15 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 

Aerospace Manufacturing and Rework 

Facilities 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 Aerospace Manufacturing and 

Rework Facilities source category, we 

identified emissions of cadmium, 

dioxins/furans, POM, mercury (both 

inorganic mercury and methyl mercury) 

and lead compounds. Because one or 

more of these PB–HAP are emitted by at 

least one facility in the Aerospace 

Manufacturing and Rework Facilities 

source category, we proceeded to the 

next step of the evaluation. In this step, 

we determined whether the facilityspecific emissions 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 emissions rate 

screening levels 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 

emissions rate screening levels are: 

Lead, cadmium, chlorinated 

dibenzodioxins and furans, mercury 

compounds and 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 emissions rates of these 

PB–HAP were compared to the emission 

rate screening levels for these PB–HAP 

to assess the potential for significant 

human health risks via non-inhalation 

pathways. We call this application of 

the TRIM.FaTE model the Tier 1 TRIMscreen or Tier 1 screen. 

For the purpose of developing 

emissions rates for our 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., for polychlorinated 

dibenzodioxins and furans 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 emissions rate of any 

PB–HAP included in the Tier 1 screen 

exceeds the Tier 1 screening emissions 

rate 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 exceeded the Tier 1 

emission rate 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 then adjust 

the risk-based Tier 1 screening level 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 

assumptions. PB–HAP emissions that do 


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8404 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

16 In doing so, 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 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. 

17The secondary NAAQS for lead 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.’’ 

not exceed these new Tier 2 screening 

levels are considered to pose no 

unacceptable risks. If the PB–HAP 

emissions for a facility exceed the Tier 

2 screening emissions rate and data are 

available, we may decide to conduct a 

more refined Tier 3 multipathway 

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 lake is fishable and 

considering plume-rise to estimate 

emissions lost above the mixing layer. If 

the Tier 3 screen is exceeded, the EPA 

may further refine the assessment. 

In evaluating the potential 

multipathway risk from emissions of 

lead compounds, rather than developing 

a screening emissions rate for them, we 

compared maximum estimated chronic 

inhalation exposures with the level of 

the current National Ambient Air 

Quality Standard (NAAQS) for lead.16

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 

Aerospace Manufacturing and Rework 

Facilities Source Category in Support of 

the January, 2015 Risk and Technology 

Review Proposal, January 2015, which is 

available in the docket for this action. 

5. 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 seven HAP, 

which we refer to as ‘‘environmental 

HAP,’’ in its screening analysis: Five 

PB–HAP and two acid gases. The five 

PB–HAP are cadmium, dioxins/furans, 

POM, mercury (both inorganic mercury 

and methyl mercury) and lead 

compounds. The two acid gases are 

hydrogen chloride (HCl) and hydrogen 

fluoride (HF). The rationale for 

including these seven 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 five 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 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, dioxins/furans, 

POM and mercury 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 NAAQS for 

lead.17 We consider values below the 

level of the secondary NAAQS for lead 

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 

potential for an adverse environmental 

effect. 

The EPA acknowledges that other 

HAP beyond the seven 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 


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PB–HAP in sediment in nearby water 

bodies. 

• 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 

population-level ecological assessment 

endpoint to screen for indirect HAP 

exposures of top consumers via the 

bioaccumulation of HAP in food chains. 

The endpoint evaluated was piscivorous 

(i.e., fish-eating) wildlife consuming 

PB–HAP-contaminated fish from nearby 

water bodies. 

For cadmium compounds, dioxins/

furans, POM and mercury, 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 (e.g., a no-observed-adverseeffect level (NOAEL)) 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. 

• 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, 

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 

ecological assessment endpoint of 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 Aerospace 

Manufacturing and Rework Facilities 

source category emitted any of the seven 

environmental HAP. For the Aerospace 

Manufacturing and Rework Facilities 

source category, we identified emissions 

of five PB–HAP and two acid gases as 

the environmental HAP. The five PB– 

HAP are cadmium, dioxins/furans, 

POM, mercury (both inorganic mercury 

and methyl mercury) and lead 

compounds. The two acid gases are HCl 

and HF. 

Because one or more of the seven 

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, mercury, POM and 

dioxins/furans, 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 

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 

eight octants. Each octant contains five 

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 


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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 

as they are in the ecological risk 

screening methodology for PB–HAP. 

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 Aerospace 

Manufacturing and Rework Facilities 

Source Category in Support of the 

January, 2015 Risk and Technology 

Review Proposal, January 2015, which is 

available in the docket for this action. 

6. 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. 

The emissions inventories developed 

from the 2011 and 2012 ICRs, 2011 NEI 

and 2005 NATA include emissions 

information for all emissions sources at 

the facilities that are part of the 

Aerospace Manufacturing and Rework 

Facilities source category. These include 

sources currently regulated by the 

Aerospace NESHAP: Primer/topcoat 

application operations, waste handling 

operations, chemical milling maskant 

application operations, cleaning 

operations and chemical and blast 

depainting operations. These also 

include emission sources not currently 

regulated by the Aerospace NESHAP: 

Specialty coatings, composite 

processing, chemical milling and metal 

finishing, wastewater, storage tanks, 

boilers, engines, chemical 

manufacturing processes, secondary 

metal production processes, heaters, soil 

remediation, transportation equipment, 

waste disposal, welding and other 

miscellaneous manufacturing processes. 

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 

Aerospace Manufacturing and Rework 

Facilities Source Category in Support of 

the January, 2015 Risk and Technology 

Review Proposal, January 2015, 

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. 

7. 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 

Aerospace Manufacturing and Rework 

Facilities Source Category in Support of 

the January, 2015 Risk and Technology 

Review Proposal, January 2015, 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, and errors in 

emission estimates and other factors. 

The emission estimates considered in 

this analysis 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, 

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 


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18Short-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. 

19U.S. EPA. National-Scale Air Toxics 

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

2001; page 85. 

20 IRIS glossary (http://www.epa.gov/NCEA/iris/

help_gloss.htm). 

21An 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. 

domain were not considered.18 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.19

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 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 

Aerospace Manufacturing and Rework 

Facilities Source Category in Support of 

the January, 2015 Risk and Technology 

Review Proposal, January 2015, 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).20 In some 

circumstances, the true risk could be as 

low as zero; however, in other 

circumstances the risk could be 

greater.21 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 


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22U.S. EPA. Reference Dose (RfD): Description 

and Use in Health Risk Assessments. Dated March 

1993. 23U.S. EPA. Methods for Derivation of Inhalation 

Reference Concentrations and Application of 

Inhalation Dosimetry. EPA/600/8–90/066F. Dated 

October 1994. 24According to the NRC report, Science and 

Judgment in Risk Assessment (NRC, 1994) 

‘‘[Default] options are generic approaches, based on 

general scientific knowledge and policy judgment, 

that are applied to various elements of the risk 

assessment process when the correct scientific 

model is unknown or uncertain.’’ The 1983 NRC 

report, Risk Assessment in the Federal Government: 

Managing the Process, defined default option as 

‘‘the option chosen on the basis of risk assessment 

policy that appears to be the best choice in the 

absence of data to the contrary’’ (NRC, 1983a, p. 63). 

Therefore, default options are not rules that bind 

the agency; rather, the agency may depart from 

them in evaluating the risks posed by a specific 

substance when it believes this to be appropriate. 

In keeping with EPA’s goal of protecting public 

health and the environment, default assumptions 

are used to ensure that risk to chemicals is not 

underestimated (although defaults are not intended 

to overtly overestimate risk). See EPA, 2004, An 

Examination of EPA Risk Assessment Principles 

and Practices, EPA/100/B–04/001 available at: 

http://www.epa.gov/osa/pdfs/ratf-final.pdf. 

25 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. 

(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, 

1994) 22 23 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 24 (e.g., factors 

of 10 or 3) used in the absence of 

compound-specific data; where data are 

available, UF may also be developed 

using compound-specific information. 

When data are limited, more 

assumptions are needed and more UF 

are used. Thus, there may be a greater 

tendency to overestimate risk in the 

sense that further study might support 

development of reference values that are 

higher (i.e., less potent) because 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. 

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 four PB–HAP. 

Two important types of uncertainty 

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.25

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 (i.e., 

represented in terms of measurable or 

estimable variables) 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 


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26 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. 

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. 

For further information on 

uncertainties and the Tier 1 and 2 

screening methods, refer to Appendix 4 

of Modeling File Preparation Memo. 

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 

same models, specifically the 

TRIM.FaTE multipathway model and 

the AERMOD air dispersion model, are 

used to estimate environmental HAP 

concentrations for both the human 

multipathway screening analysis and for 

the environmental screening analysis. 

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.26

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 

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 

for programmatic levels (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.5 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 


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27Although 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. 

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 

seven HAP in the environmental risk 

screening assessment: Cadmium, 

dioxins/furans, POM, mercury (both 

inorganic mercury and methyl mercury), 

lead compounds, HCl and HF, where 

applicable. These seven 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 seven 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 seven 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 the 

Aerospace Manufacturing and Rework 

Facilities Source Category in Support of 

the January, 2015 Risk and Technology 

Review Proposal, January 2015, 

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) 27 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 emissions 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. 

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; 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 

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 1-in-10 thousand should 

ordinarily be the upper end of the range 

of acceptability. As risks increase above 

this benchmark, they become 

presumptively less acceptable under 

CAA section 112, and would be 

weighed with 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 


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28EPA’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 memo 

to this rulemaking docket from David Guinnup 

entitled, EPA’s Actions in Response to the Key 

Recommendations of the SAB Review of RTR Risk 

Assessment Methodologies. 

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.’’ 28

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 hazard indices from all noncarcinogens 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 

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. 

• 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). 

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 Aerospace Manufacturing 

and Rework Facilities source category, 

as well as the costs, non-air impacts and 

energy implications associated with the 

use of these technologies. Additionally, 

we requested information from facilities 

regarding developments in practices, 

processes or control technology. 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 actions are we taking pursuant 

to CAA sections 112(d)(2) and 

112(d)(3)? 

We are not proposing any new 

emissions limitations to the NESHAP 

other than with respect to specialty 

coatings. In this action, we are 

proposing the following revisions to the 

Aerospace NESHAP to ensure the 

standards are consistent with the 

requirements of the CAA as interpreted 

by the courts: adding standards to limit 

organic and inorganic HAP emissions 

from specialty coating application 

operations and updating the provisions 

regulating emissions during periods of 

SSM. Additionally, we are adding an 

alternative compliance demonstration 

provision for all types of coating 

application operations (primers, 

topcoats, specialty coatings and 

chemical milling maskants) in certain 

situations. The results and proposed 

decisions based on the analyses 

performed pursuant to CAA section 

112(d)(2) and (3) are presented below. 

We are proposing to establish MACT 

standards specific to specialty coating 

application operations to ensure the 

standards are consistent with the 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
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29For more details see the discussion of Sierra 

Club v. EPA, 479 F. 3d 875 (D.C. Cir. 2007) in 

section II.E of this preamble, which found that the 

EPA may not set ‘‘no emissions reductions’’ MACT 

floors. 30 Initial List of Categories of Sources Under 

Section 112(c)(1) of the Clean Air Act Amendments 

of 1990. 57 FR 31576, July 17, 1992. 

31National Emission Standards for Hazardous Air 

Pollutants; Revision of Initial List of Categories of 

Sources and Schedule for Standards Under Sections 

112(c) and (e) of the Clean Air Act Amendments of 

1990. 61 FR 28197, June 4, 1996. 32See the EPA’s ‘‘Coatings and Composites 

Coordinated Rule Development’’ Web page at 

http://www.epa.gov/ttnatw01/coat/coat.html for a 

full list of surface coating-related NESHAP, and 

links to Web pages specific to each surface coating 

NESHAP. 

requirements of the CAA as interpreted 

by the courts. Under CAA section 

112(d)(3), the EPA is required to 

promulgate emissions limits for all HAP 

emitted from major source categories.29

Specialty coatings are a source of HAP 

emissions from the Aerospace 

Manufacturing and Rework Facilities 

source category that is not currently 

regulated under the Aerospace 

NESHAP. We are proposing organic 

HAP content limits to reduce organic 

HAP emissions and equipment and 

work practice standards to reduce 

inorganic HAP emissions associated 

with specialty coating application. Refer 

to section IV.E.1 of this preamble for a 

description of specialty coating 

application operations, associated 

emissions and how this emissions 

source is addressed in the current 

Aerospace NESHAP, and how the EPA 

established the MACT floor for specialty 

coating application operations. Section 

IV.E.1 of this preamble also includes the 

EPA’s rationale for proposing this 

standard, as well as how the EPA 

established the MACT floor for specialty 

coating application operations and the 

estimated costs for complying with the 

proposed standard. The EPA is 

proposing to add these standards for 

specialty coatings because they are a 

source of HAP emissions from the 

Aerospace Manufacturing and Rework 

Facilities source category and EPA had 

not previously established MACT 

standards for these emissions points. 

These proposed changes are necessary 

to ensure the emissions standards are 

consistent with the requirements of the 

CAA as interpreted by the courts and 

are unrelated to the risk findings. 

The EPA is also proposing to revise 

the provisions affecting periods of SSM 

to clarify that the emission limitations 

in the Aerospace NESHAP apply at all 

times, including during these SSM 

periods. Refer to section IV.E.3 of this 

preamble for a description of the EPA’s 

proposed revisions to the SSM 

provisions for aerospace manufacturing 

and rework operations. These proposed 

changes to the SSM provisions are 

necessary to ensure the emissions 

standards are consistent with the 

requirements of the CAA as interpreted 

by the courts and are unrelated to the 

risk findings. 

The EPA also collected emissions data 

and performed a risk analysis for certain 

emissions points outside of the source 

category—chemical milling and metal 

finishing operations, waste water 

operations, storage tanks and composite 

operations that are related to aerospace 

manufacturing and rework, but are not 

surface coating operations. The data 

collected for these non-surface coating 

operations were used to characterize the 

risk presented from these operations in 

order to estimate the total risk from the 

entirety of each aerospace 

manufacturing and rework facility. The 

EPA is not proposing to expand the 

Aerospace Manufacturing and Rework 

Facilities source category to include 

these operations, which are not surface 

coating operations and were not part of 

the original source category and which, 

as explained below, did not present 

unacceptable risks. The initial and 

subsequent listings of source categories 

for regulation under section 112 of the 

CAA included Aerospace 

Manufacturing and Rework Facilities 

only as a surface coating source 

category.30 31

B. What are the results of the risk 

assessment and analyses? 

1. Inhalation Risk Assessment Results 

Table 2 of this preamble provides an 

overall summary of the results of the 

inhalation risk assessment. 

TABLE 2—AEROSPACE MANUFACTURING AND REWORK FACILITIES INHALATION RISK ASSESSMENT RESULTS

Maximum 

individual 

cancer risk 

(-in-1 million) a

Estimated 

population at 

increased risk 

levels of cancer 

Estimated 

annual 

cancer 

incidence 

(cases per 

year) 

Maximum 

chronic 

non-cancer 

TOSHI b

Maximum screening acute non-cancer HQ c

Actual Emissions 

10 ...................... ≥ 1-in-1 million: 180,000 .......

≥ 10-in-1 million: 1,500 

≥ 100-in-1 million: 0 

0.02 0.5 HQREL = 2 (ethylene glycol ethyl ether acetate). 

Allowable Emissions d

10 ...................... ≥ 1-in-1 million: 180,000 .......

≥ 10-in-1 million: 2,000 

≥ 100-in-1 million: 0 

0.02 0.5 

aEstimated maximum individual excess lifetime cancer risk due to HAP emissions from the source category. 

b Maximum TOSHI. The target organ with the highest TOSHI for the Aerospace Manufacturing and Rework Facilities source category for both 

actual and allowable emissions is the kidney system. cSee Section III.A.3 of this preamble for explanation of acute dose-response values. Acute assessments are not performed on allowable emissions. dThe development of allowable emission estimates can be found in the memorandum titled, Aerospace Manufacturing and Rework Facilities 

RTR Modeling File Preparation, December 2014, which is available in the docket. 

The inhalation risk modeling 

performed to estimate risks based on 

actual and allowable emissions relied 

primarily on emissions data from the 

ICRs and calculations described in the 

memorandum titled, Aerospace 


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Manufacturing and Rework Facilities 

RTR Modeling File Preparation, 

December 2014, which is available in 

the docket for this action. The results of 

the chronic baseline inhalation cancer 

risk assessment indicate that, based on 

estimates of current actual emissions, 

the MIR posed by the Aerospace 

Manufacturing and Rework Facilities is 

10-in-1 million, with emissions of 

strontium chromate, from coating 

operations accounting for the majority 

of the risk. The total estimated cancer 

incidence from Aerospace 

Manufacturing and Rework Facilities 

based on actual emission levels is 0.02 

excess cancer cases per year or one case 

every 50 years, with emissions of 

strontium chromate and chromium 

compounds contributing 66 percent and 

15 percent, respectively, to the cancer 

incidence. In addition, we note that 

approximately 1,500 people are 

estimated to have cancer risks greater 

than or equal to 10-in-1 million, and 

approximately 180,000 people are 

estimated to have risks greater than or 

equal to 1-in-1 million as a result of 

actual emissions from this source 

category. 

When considering MACT-allowable 

emissions, the MIR is estimated to be up 

to 10-in-1 million, driven by emissions 

of strontium chromate from coating 

operations. The estimated cancer 

incidence is estimated to be 0.02 excess 

cancer cases per year, or one excess case 

in every 50 years. Approximately 2,000 

people are estimated to have cancer 

risks greater than or equal to 10-in-1 

million and approximately 180,000 

people are estimated to have cancer 

risks greater than or equal to 1-in-1 

million considering allowable emissions 

from Aerospace Manufacturing and 

Rework Facilities. 

The maximum modeled chronic noncancer HI (TOSHI) value for the source 

category based on actual emissions is 

estimated to be 0.5, driven by cadmium 

compounds emissions from blast 

depainting. When considering MACTallowable emissions, the maximum 

chronic non-cancer TOSHI value is 

estimated to be 0.5, also driven by 

cadmium compounds emissions from 

blast depainting. 

2. Acute Risk Results 

Our screening analysis for worst-case 

acute impacts based on actual emissions 

indicates the potential for one pollutant, 

ethylene glycol ethyl ether acetate, from 

one facility, to have HQ values above 1, 

based on its REL value. One hundred 

forty-three of the 144 Aerospace 

Manufacturing and Rework Facilities 

had an estimated worst-case HQ less 

than or equal to 1 for all HAP. 

To better characterize the potential 

health risks associated with estimated 

worst-case acute exposures to HAP from 

the source category at issue and in 

response to a key recommendation from 

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

section 112(f) RTR risk assessment 

methodologies, we examine a wider 

range of available acute health metrics 

than we do for our chronic risk 

assessments. This is in 

acknowledgement that there are 

generally more data gaps and 

inconsistencies in acute reference 

values than there are in chronic 

reference values. 

By definition, the acute CalEPA REL 

represents a health-protective level of 

exposure, with no risk anticipated 

below those levels, even for repeated 

exposures; however, the health risk 

from higher-level exposures is 

unknown. Therefore, when a CalEPA 

REL is exceeded and an AEGL–1 or 

ERPG–1 level is available (i.e., levels at 

which mild effects are anticipated in the 

general public for a single exposure), we 

have used them as a second comparative 

measure. Historically, comparisons of 

the estimated maximum off-site 1-hour 

exposure levels have not been typically 

made to occupational levels for the 

purpose of characterizing public health 

risks in RTR assessments. This is 

because occupational ceiling values are 

not generally considered protective for 

the general public since they are 

designed to protect the worker 

population (presumed healthy adults) 

for short-duration (less than 15-minute) 

increases in exposure. As a result, for 

most chemicals, the 15-minute 

occupational ceiling values are set at 

levels higher than a 1-hour AEGL–1, 

making comparisons to them irrelevant 

unless the AEGL–1 or ERPG–1 levels are 

also exceeded. 

The worst-case maximum estimated 

1-hour exposure to ethylene glycol ethyl 

ether acetate outside the facility fence 

line for the source categories is 0.3 mg/ 

m3. This estimated worst-case exposure 

exceeds the 1-hour REL by a factor of 2 

(HQREL = 2). All other HAP in this 

analysis have worst-case acute HQ 

values of 1 or less (maximum HQAEGL¥1

= 0.02 for phenol, maximum HQERPG¥1

= 0.03 for phenol) indicating that they 

carry no potential to pose acute 

concerns. 

In characterizing the potential for 

acute non-cancer impacts of concern, it 

is important to remember the upward 

bias of these exposure estimates (e.g., 

worst-case meteorology coinciding with 

a person located at the point of 

maximum concentration during the 

hour) and to consider the results along 

with the conservative estimates used to 

develop peak hourly emissions as 

described in the Modeling File 

Preparation Memo (which is available in 

the docket for this action) for a detailed 

description of how the hourly emissions 

were developed for this source category. 

3. Multipathway Risk Screening Results 

Results of the worst-case Tier I 

screening analysis indicate that PB– 

HAP emissions of cadmium compounds 

or mercury compounds did not exceed 

the screening emission rates. Neither 

dioxins nor polycyclic aromatic 

hydrocarbons (PAH) are emitted by any 

source in the source category. 

4. Environmental Risk Screening Results 

As described in section III.A of this 

preamble, we conducted a screeninglevel evaluation of the potential adverse 

environmental risks associated with 

emissions of the following 

environmental HAP from the Aerospace 

Manufacturing and Rework Facilities 

source category: lead, mercury, 

cadmium, HCl and HF. 

In the Tier 1 screening analysis for 

PB–HAP (other than lead compounds, 

which were evaluated differently), the 

individual modeled Tier 1 

concentrations for mercury and 

cadmium did not exceed any ecological 

benchmark for any facility in the source 

category. For lead compounds, we did 

not estimate any exceedances of the 

secondary lead NAAQS. 

For HF and 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 the ecological benchmarks. 

In addition, each individual modeled 

concentration of HCl and HF (i.e., each 

off-site data point in the modeling 

domain) was below the ecological 

benchmarks for all facilities. 

5. Facility-Wide Risk Results 

The facility-wide chronic MIR and 

TOSHI were estimated based on 

emissions from all sources at the 

identified facilities (both MACT and 

non MACT sources). The results of the 

facility-wide assessment for cancer risks 

indicate that 44 facilities with aerospace 

manufacturing and rework processes 

have a facility-wide cancer MIR greater 

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

maximum facility-wide cancer MIR is 

20-in-1 million, primarily driven by 

arsenic and chromium (VI) compounds, 

from internal combustion engines. The 

maximum facility-wide TOSHI for the 

source category is estimated to be 0.5, 

primarily driven by emissions of 

hexamethylene-1,6-diisocyanate from 

specialty coatings operations. 


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6. What demographic groups might 

benefit from this regulation? 

To examine the potential for any 

environmental justice (EJ) issues that 

might be associated with the source 

category, we performed a demographic 

analysis, which is an assessment of risks 

to individual demographic groups, of 

the population close to the facilities. In 

this analysis, we evaluated the 

distribution of HAP-related cancer risks 

and non-cancer hazards from the 

Aerospace Manufacturing and Rework 

Facilities across different social, 

demographic and economic 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 SocioEconomic Factors for Populations Living 

Near Aerospace Facilities, available in 

the docket for this action. 

The results of the demographic 

analysis are summarized in Table 3 of 

this preamble. These results, for various 

demographic groups, are based on the 

estimated risks from actual aerospace 

manufacturing and rework emissions 

levels for the population living within 

50 km of the facilities. 

TABLE 3—AEROSPACE MANUFACTURING AND REWORK FACILITIES DEMOGRAPHIC RISK ANALYSIS RESULTS

Nationwide 

Population with 

cancer risk at or 

above 1-in-1 

million due to 

emissions from 

aerospace facilities 

Population 

with chronic 

hazard index 

above 1 due 

to emissions 

from aerospace facilities 

Total Population ......................................................................................................................... 312,861,265 179,074 0 

Race by Percent 

White .......................................................................................................................................... 72 64 NA 

All Other Races ......................................................................................................................... 28 36 NA 

Race by Percent 

White .......................................................................................................................................... 72 64 NA 

African American ....................................................................................................................... 13 19 NA 

Native American ........................................................................................................................ 1 1 .5 NA 

Other and Multiracial ................................................................................................................. 14 16 NA 

Ethnicity by Percent 

Hispanic ..................................................................................................................................... 17 16 NA 

Non-Hispanic ............................................................................................................................. 83 84 NA 

Income by Percent 

Below Poverty Level .................................................................................................................. 14 19 NA 

Above Poverty Level .................................................................................................................. 86 81 NA 

Education by Percent 

Over 25 and without High School Diploma ............................................................................... 15 17 NA 

Over 25 and with a High School Diploma ................................................................................. 85 83 NA

The results of the Aerospace 

Manufacturing and Rework Facilities 

baseline risk assessment indicate that 

emissions from the source category 

expose approximately 180,000 people to 

a cancer risk at or above 1-in-1 million 

and no one is predicted to have a 

chronic non-cancer TOSHI greater than 

1. 

The analysis indicates that the 

percentages of the population exposed 

to a cancer risk greater than or equal to 

1-in-1 million and living within 50 km 

of the 144 aerospace facilities is higher 

for minority populations, 36-percent 

exposed versus the national minority 

population average of 28 percent. The 

specific demographics of the population 

within 50 km of the facilities indicate 

potential disparities in certain 

demographic groups, including the 

‘‘African American’’ and ‘‘Below the 

Poverty Level.’’ 

C. 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 MIR of 

approximately 1 in 10 thousand.’’ 54 FR 

38045, September 14, 1989. For the 

Aerospace Manufacturing and Rework 

Facilities source category, we estimate, 

based on both actual and allowable 

emissions, an MIR of 10-in-1 million 

driven by emissions of strontium 

chromate from coating operations. We 

estimate that, based on actual emissions, 

about 1,500 people are estimated to 

have cancer risks greater than or equal 

to 10-in-1 million and, based on 

allowable emissions, about 2,000 people 

have cancer risks greater than or equal 

to 10-in-1 million. We estimate that 

approximately 180,000 people are 

estimated to have risks greater than or 

equal to 1-in-1 million based on both 

actual and allowable emissions from 

this source category. The total estimated 

incidence of cancer for this source 

category due to inhalation exposures, 

based on both actual and allowable 

emissions, is 0.02 excess cancer cases 


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per year, or 1 case in 50 years. The 

agency estimates that the maximum 

chronic non-cancer TOSHI from 

inhalation exposure, based on both 

actual and allowable emissions, from 

this source category, is 0.5, with 

cadmium compounds emissions from 

blast depainting accounting for the 

majority of the TOSHI. 

The multipathway screening analysis, 

based upon actual emissions, indicates 

that PB–HAP emissions of both 

cadmium compounds and mercury 

compounds did not exceed the 

screening emission rates. Neither 

dioxins nor PAH are emitted by any 

source in the source category. In 

evaluating the potential for 

multipathway effects from emissions of 

lead, modeled maximum annual lead 

concentrations were compared to the 

secondary NAAQS for lead (0.15 mg/m3). 

Results of this analysis estimate that the 

NAAQS for lead would not be exceeded 

at any off-site locations. 

The screening assessment of worstcase acute inhalation impacts from 

baseline actual emissions indicates that 

the worst-case maximum estimated 1- 

hour exposure to ethylene glycol ethyl 

ether acetate outside the facility fence 

line exceeds the 1-hour REL by a factor 

of 2 (HQREL = 2). This exceedance was 

only predicted to occur in a remote, 

non-inhabited area just adjacent to the 

facility fence line for 2 hours a year. All 

other HAP in this analysis have worstcase acute HQ values of 1 or less 

(maximum HQAEGL¥1 = 0.02 for phenol, 

maximum HQERPG¥1 = 0.03 for phenol) 

indicating that they carry no potential to 

pose acute concerns. 

In determining whether risks are 

acceptable for this source category, the 

EPA considered all available health 

information including any uncertainty 

in risk estimates. Also, as noted above, 

the agency estimated risk from both 

actual and allowable emissions. While 

there are uncertainties associated with 

both the actual and allowable emissions, 

we consider the allowable emissions to 

be an upper bound, based on the 

conservative methods we used to 

calculate allowable emissions. 

The risk results indicate that both the 

actual and allowable inhalation cancer 

risks to the individual most exposed are 

no greater than approximately 10-in-1 

million, which is considerably less than 

the presumptive limit of acceptability 

(i.e., 100-in-1 million). The maximum 

chronic non-cancer hazard indices for 

both the actual and allowable inhalation 

non-cancer risks to the individual most 

exposed of 0.5 is less than 1. 

The maximum acute non-cancer HQ 

for all pollutants was 2 based on the 

REL for ethylene glycol ethyl ether 

acetate. This value was only predicted 

to occur during 2 hours per year in a 

remote location adjacent to a single 

facility’s fenceline. All other acute risks 

are estimated to be below a noncancer 

HI threshold of 1. 

The multipathway screening analysis 

indicates that PB–HAP emissions did 

not exceed the screening emission rates 

for any compound evaluated. 

Considering all of the health risk 

information and factors discussed 

above, including the uncertainties 

discussed in section III.A.8 of this 

preamble, the EPA proposes that the 

risks at baseline are acceptable since the 

cancer risks are well below the 

presumptive limit of acceptability and 

the non-cancer results indicate there is 

minimal likelihood of adverse noncancer health effects due to HAP 

emissions from this source category. 

2. Ample Margin of Safety Analysis and 

Proposed Controls 

Under the ample margin of safety 

analysis, we evaluate the cost and 

feasibility of available control 

technologies and other measures 

(including the controls, measures and 

costs evaluated under the technology 

review) that could be applied in this 

source category to further reduce the 

risks due to emissions of HAP identified 

in our risk assessment, as well as the 

health impacts of such potential 

additional measures. As noted in our 

discussion of the technology review in 

section III.C of this preamble, no 

measures (beyond those already in place 

or that we are proposing today under 

CAA sections 112 (d)(2) and (d)(3)) were 

identified for reducing HAP emissions 

from the Aerospace Manufacturing and 

Rework Facilities source category. 

Therefore, we propose that the current 

standards provide an ample margin of 

safety to protect public health. 

Although the current standards were 

found to provide an ample margin of 

safety to protect public health, we are 

proposing additional standards under 

CAA sections 112(d)(2) and (3) that 

address previously unregulated 

emissions of HAP from specialty coating 

application operations. The additional 

standards are being proposed to address 

a deficiency in the Aerospace NESHAP 

as discussed previously in section II.E. 

of this preamble. We are proposing 

organic HAP and volatile organic 

compound (VOC) content limits for 

specialty coatings that are equal to the 

VOC content limits specified in the 

Aerospace CTG for specialty coatings. 

Facilities that do not use specialty 

coatings and those in nonattainment 

areas that are currently complying with 

the Aerospace CTG limits for their 

specialty coating operations will not 

have to do anything new to meet these 

requirements. The 74 facilities located 

in attainment areas that reported using 

specialty coatings in the 2011 ICR may 

not be using compliant coatings and 

may need to use alternative coatings, 

direct the emissions stream to an addon control device or use the averaging 

option to demonstrate compliance with 

implement the standards. We are also 

proposing that specialty coating 

application operations be subject to the 

same equipment standards (i.e., use 

high-efficiency application equipment) 

currently required for primer and 

topcoat application operations. Further, 

we are proposing to require that 

specialty coating application operations 

meet current work practice standards for 

primer and topcoat application 

operations for inorganic HAP emissions. 

The estimated emission reductions 

resulting from these proposed HAP 

content limits, equipment standards and 

work practice standards for specialty 

coatings are 58 tons of HAP per year. As 

noted above, we are proposing that the 

MACT standard, prior to the 

implementation of these proposed 

standards for specialty coatings, 

provides an ample margin of safety to 

protect public health. Therefore, we 

maintain that, after the implementation 

of these standards for specialty coatings, 

the rule will continue to provide an 

ample margin of safety to protect public 

health. Consequently, based on current 

information, we do not expect it will be 

necessary to conduct another residual 

risk review under CAA section 112(f) for 

this source category 8 years following 

promulgation of new emission limits 

and equipment and work practice 

standards for specialty coatings, merely 

due to the addition of these MACT 

requirements. While our decisions on 

risk acceptability and ample margin of 

safety are supported even in the absence 

of these reductions for specialty 

coatings, if we finalize the proposed 

requirements for these sources, they 

would further strengthen our 

conclusions that risk is acceptable with 

an ample margin of safety to protect 

public health. 

Although we did not identify any new 

technologies, other than for specialty 

coatings application operations, to 

reduce risk for this source category, we 

are specifically requesting comment on 

whether there are additional control 

measures that may be able to reduce 

risks from the source category. We 

request any information on potential 

emission reductions of such measures, 

as well the cost and health impacts of 


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32See the EPA’s ‘‘Coatings and Composites 

Coordinated Rule Development’’ Web page at 

http://www.epa.gov/ttnatw01/coat/coat.html for a 

full list of surface coating-related NESHAP, and 

links to Web pages specific to each surface coating 

NESHAP. 

such reductions to the extent they are 

known. 

3. Adverse Environmental Effects 

Based on the results of our 

environmental risk screening 

assessment, we conclude that there is 

not an adverse environmental effect as 

a result of HAP emissions from the 

Aerospace Manufacturing and Rework 

Facilities 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. 

D. What are the results and proposed 

decisions based on our technology 

review? 

As described in section III.C of this 

preamble, our technology review 

focused on identifying developments in 

practices, processes and control 

technologies for the Aerospace 

Manufacturing and Rework Facilities 

source category. The EPA reviewed 

various information sources regarding 

emission sources that are currently 

regulated by the Aerospace NESHAP, 

which include primer and topcoat 

application operations, maskant 

application operations, cleaning 

operations, chemical and blast 

depainting operations and waste storage 

and handling operations. 

For the technology review, we 

conducted a search of the EPA’s RACT/ 

BACT/LAER Clearinghouse (RBLC) and 

regulatory actions (MACT standards, 

area sources standards and residual risk 

standards) subsequent to promulgation 

of the 1995 Aerospace NESHAP.32 We 

reviewed Washington State’s records of 

Prevention of Significant Deterioration 

(PSD) permits. Further, we considered 

numerous relevant regional and state 

regulations (e.g., California, Missouri, 

Delaware and Arizona), the Ozone 

Transport Commission serving the 

Northeastern United States and state 

implementation plans. We reviewed the 

database of responses to the 2011 ICR to 

determine the technologies and 

practices reported by industry. 

We reviewed these sources for 

information on add-on control 

technologies, other process equipment, 

work practices and procedures and 

process changes or pollution prevention 

alternatives that were not considered 

during development of the Aerospace 

NESHAP. We also looked for 

information on improvements in add-on 

control technology, other process 

equipment, work practices and 

procedures and process changes or 

pollution prevention alternatives that 

have occurred since development of the 

Aerospace NESHAP. Regarding process 

changes or pollution prevention 

alternatives, we searched for 

advancements in the use of low-HAP 

coatings and solvents, advancements in 

the use of high solids coatings and the 

adoption of lower VOC content limits 

for coatings and solvents. 

The following sections summarize our 

technology review results for each of 

these emission sources. 

1. Primer and Topcoat Application 

Operations 

As defined in the Aerospace NESHAP 

(see 40 CFR 63.742), a coating is a 

material that is applied to the surface of 

an aerospace vehicle or component to 

form a decorative or functional solid 

film, or the solid film itself. A primer is 

the first layer and any subsequent layers 

of coating prior to the topcoat and is 

typically used for corrosion prevention, 

protection from the environment, 

functional fluid resistance and adhesion 

of subsequent coatings. A topcoat is a 

coating that is applied over one or more 

layers of a primer for appearance, 

identification, camouflage or protection. 

Specialty coatings are not included in 

the categories of primers or topcoats 

currently subject to regulation under 40 

CFR 63.745. 

Most aerospace coatings contain a 

mixture of organic solvents that may be 

HAP, and also inorganic pigments, such 

as various metal compounds, which 

may also be HAP. The organic HAP 

emissions from the application of 

primers and topcoats occur from the 

evaporation of organic solvents during 

mixing, application and drying. 

Emissions of inorganic HAP from sprayapplied coating operations, typically 

metal compounds (e.g., chromium, 

cadmium compounds), occur when 

coating particles do not adhere to the 

surface being coated (i.e., overspray). 

The organic and inorganic emissions 

from coating application occur in large 

open areas, such as hangars or in 

partially or fully enclosed spaces, such 

as within spray booths. 

The existing Aerospace NESHAP 

requires the following organic HAP and 

VOC content limits for uncontrolled 

primers and topcoats (40 CFR 

63.745(c)): 

• Primers: 2.9 lb/gal (less water) as 

applied; or 4.5 lb/gal (less water) as 

applied for general aviation rework 

facilities, or 5.4 lb/gal (less water) as 

applied, to large commercial aircraft 

components (parts or assemblies) or 

fully assembled, large commercial 

aircraft. 

• Topcoats: 3.5 lb/gal (less water) as 

applied; or 4.5 lb/gal (less water) as 

applied for general aviation rework 

facilities. 

Alternatively, a control system can be 

used to capture and control organic 

HAP and VOC emissions from the 

primer or topcoat application 

operations. The system must achieve an 

overall control efficiency of 81 percent 

of organic HAP and VOC emissions (40 

CFR 63.745(d)). 

In addition, the Aerospace NESHAP 

requires the use of one of the following 

coating application techniques (40 CFR 

63.745(f)): 

• Flow/curtain coat application. 

• Dip coat application. 

• Roll coating. 

• Brush coating. 

• Cotton-tipped swab application. 

• Electrodeposition (dip) coating. 

• High volume low pressure (HVLP) 

spraying. 

• Electrostatic spray application. 

• Other coating application methods 

that achieve emission reductions 

equivalent to HVLP or electrostatic 

spray application methods. 

The Aerospace NESHAP also includes 

operating requirements for the 

application of primers or topcoats that 

contain inorganic HAP, including 

control of spray booth exhaust streams 

with either particulate filters or 

waterwash spray booths (40 CFR 

63.745(g)). 

Based on the technology review for 

primers and topcoats, we did not 

identify any practices, processes or 

control technologies beyond those 

already required by the Aerospace 

NESHAP. A brief summary of the EPA’s 

findings in conducting its RTR review of 

primer and topcoat application 

operations follows. For a detailed 

discussion of the EPA’s findings, refer to 

the memorandum, Technology Review 

for Primer and Topcoat Application 

Operations in the Aerospace Source 

Category, January 2015, available in the 

docket for this action. 

In reviewing add-on control 

technologies or other equipment and 

work practices and procedures, we did 

not identify any add-on control 

technologies, other equipment or work 

practices and procedures that had not 

previously been considered during 

development of the Aerospace NESHAP, 

nor did we identify any developments 

in the same since the promulgation of 

the NESHAP. 

Based on our search of the RBLC, we 

did not find any more stringent 

requirements. We identified one facility 


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33 63 FR 46525, September 1, 1998. 

in Washington State, for which a Best 

Achievable Control Technology (BACT) 

analysis was completed in September 

2014, for constructing new buildings 

needed for producing new models of 

large commercial airplanes, including 

the building and surface coating of 

composite aircraft wings. The surface 

coating operations on these aircraft 

wings would involve the use of primers 

and topcoats that are subject to the 

limits in 40 CFR 63.745. The BACT 

analysis concluded that there are no 

demonstrations of add-on controls at 

facilities performing surface coating 

comparable to large commercial aircraft 

wing components. The analysis also 

concluded that add-on controls would 

not be cost effective for surface coating 

of large components, such as wings, 

much less fully assembled large 

commercial aircraft. 

In reviewing improvements in add-on 

control technologies or other equipment 

that had previously been considered 

during development of the Aerospace 

NESHAP, specifically in conducting a 

technology review of the wood 

manufacturing industry, we found that 

the Wood Furniture Manufacturing 

NESHAP, 40 CFR part 63, subpart JJ, 

requires the use of high-efficiency spray 

guns (e.g., airless spraying, air assisted 

airless spraying, electrostatic spraying 

and HVLP spray guns) and prevents the 

use of conventional spray guns. 

Although the Aerospace NESHAP does 

not specifically prohibit the use of 

conventional spray methods, it does 

specify that only spray application 

methods that are equivalent to HVLP or 

electrostatic spray application methods 

may be used. Because conventional 

spray guns can be used only if they can 

achieve the same efficiency as HVLP or 

electrostatic spray application methods, 

the Aerospace NESHAP and the Wood 

Furniture Manufacturing NESHAP are 

essentially equivalent. No other new 

developments in add-on control 

technologies or other equipment were 

found. 

The EPA reviewed the 2011 ICR data 

for advancements in the use of low-HAP 

liquid primers and topcoats as process 

changes and pollution prevention 

alternatives that could be transferred to 

and used in this source category and 

that were not identified and considered 

during development of the Aerospace 

NESHAP. In this review, we found some 

facilities with weighted-average HAP 

content values below the HAP and VOC 

content limits for primers and topcoats 

in the Aerospace NESHAP. However, 

the data collected by the ICR cannot be 

compared directly with the HAP and 

VOC content limits in the Aerospace 

NESHAP because the NESHAP limits 

are based on grams of HAP per liter of 

coating, less water. The ICR asked for 

readily available data, such as data from 

product sheets and material safety data 

sheets, which did not provide data on 

the water content of the coatings. As a 

result, we cannot accurately convert the 

reported HAP contents from the ICR to 

the same basis as in the Aerospace 

NESHAP. Moreover, we believe that if 

the coatings in the ICR contained water 

and the water content of the coatings is 

removed, then the corrected HAP 

content of the coatings would increase 

and the apparent difference between the 

ICR data and the NESHAP limits would 

be reduced. 

Finally, many of the currently used 

coatings have already been reformulated 

to meet the current MACT HAP content 

limits. Manufacturers of aerospace 

vehicles are constrained to using certain 

types of primers and topcoats based on 

the market segment for which the 

coating is intended (i.e., military 

original equipment manufacturer 

(OEM), military rework, commercial 

OEM or commercial rework) and the 

unique circumstances and design 

considerations within each market 

segment. In addition to being regulated 

by the Aerospace NESHAP, aerospace 

vehicle manufacturing and rework 

operations are also regulated by the 

Federal Aviation Administration (FAA), 

the Department of Defense and specific 

customer requirements. As outlined in 

the EPA’s 1998 promulgation of 

amendments to the Aerospace 

NESHAP,33 affected sources must 

comply with FAA Airworthiness 

Directives (AD) that can potentially 

require the use of chemicals containing 

HAP, and affected sources may have to 

obtain alternative means of compliance 

for AD to allow for the substitution of 

non-HAP materials. These multiple 

regulations can result in lengthy 

processes for qualifying new paint 

systems. 

Based on a finding of no new 

developments in practices, processes 

and control technologies in the 

technology review for primer and 

topcoat application operations, we are 

not proposing to revise the Aerospace 

NESHAP HAP and VOC content limit 

requirements for primer and topcoat 

application operations pursuant to CAA 

section 112(d)(6). For further discussion 

of the technology review results, refer to 

the memorandum, Technology Review 

for Primer and Topcoat Application 

Operations in the Aerospace Source 

Category, January 2015, available in the 

docket for this action. 

2. Chemical Milling Maskant 

Application Operations 

In the process of chemical milling, an 

etchant solution is used to chemically 

reduce the thickness of selected areas of 

metal parts. The process is typically 

used when the size or shape of the part 

precludes mechanical milling or when 

chemical milling is advantageous due to 

shorter processing time or its batch 

capability. Before chemical milling, a 

maskant is applied to the part, allowed 

to cure and is then removed from 

selected areas of the part where metal is 

to be removed by the etchant. The 

maskant remaining on the part protects 

those areas from the etchant. Maskants 

are applied by brushing, dipping, 

spraying or flow coating. Organic HAP 

emissions occur through evaporation of 

the solvent in the maskant, typically 

toluene, xylene or perchloroethylene, as 

the maskant is applied and while it 

cures. 

There are two subcategories of 

chemical milling maskants in the 

Aerospace NESHAP. Type I maskants 

are used with chemical milling etchants 

that contain dissolved sulfur and no 

amines, and Type II maskants are used 

with etchants that are strong sodium 

hydroxide solutions containing amines. 

The Aerospace NESHAP requires the 

following organic HAP and VOC content 

limits for uncontrolled chemical milling 

maskants (40 CFR 63.747(c)): 

• Type I: 5.2 pounds organic HAP per 

gallon (622 g/L) less water, as applied. 

• Type II: 1.3 pounds of organic HAP 

per gallon (160 g/L) less water, as 

applied. 

These requirements do not apply to 

touch-up of scratched surfaces or 

damaged maskant and touch-up of 

trimmed edges. Alternatively, a control 

system can be used to capture and 

control emissions from the maskant 

application operation. The system must 

achieve an overall control efficiency of 

81 percent (40 CFR 63.747(d)). 

Based on the technology review for 

chemical milling maskants, we did not 

identify any add-on control 

technologies, other equipment or work 

practices and procedures that had not 

previously been considered during 

development of the Aerospace NESHAP. 

Additionally, we did not identify any 

improvements that could be transferred 

to this source category. In our search of 

the RBLC, we also did not find any more 

stringent requirements. We did find that 

some California air quality management 

districts require more stringent VOC 

content limits than those in the 

Aerospace NESHAP and have higher 

overall minimum control requirements 

for the use of add-on control technology. 


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However, the EPA did not find any 

chemical milling maskant application 

operations located in these two districts 

that are subject to these more stringent 

limits. 

Based on a finding of no new 

developments in practices, processes 

and control technologies in this 

technology review, we are not proposing 

revisions to the Aerospace NESHAP for 

chemical milling maskant application 

operations pursuant to CAA section 

112(d)(6). Refer to the memorandum, 

Technology Review for Chemical Milling 

Maskant Application Operations in the 

Aerospace Source Category, January 

2015, available in the docket for this 

action, for more a more detailed 

description of the technology review 

results. 

3. Cleaning Operations 

At Aerospace Manufacturing and 

Rework Facilities, cleaning operations 

are used at essentially every processing 

step of aerospace surface coating, from 

preparing surfaces to be coated to 

cleaning the coating application 

equipment. The cleaning operations 

regulated by the current Aerospace 

NESHAP include hand-wipe cleaning, 

spray gun cleaning and flush cleaning, 

as well as housekeeping measures for 

storage, handling and transfer of 

cleaning solvents and solvent-laden 

materials. 

The liquid cleaning solutions used in 

cleaning operations for the aerospace 

industry contain organic solvents, and 

some of these organic solvents are HAP. 

Organic HAP emissions from the 

cleaning operations are often fugitive in 

nature, resulting from the evaporation of 

the volatile portion of the cleaning 

solvent in large open areas, such as 

hangars. They may also be emitted from 

stacks when the solvents are used in 

partially or fully enclosed spray booths 

that are ventilated through stacks. 

The current Aerospace NESHAP 

requires that hand-wipe and flush 

cleaning solvents meet certain 

composition requirements, or that the 

cleaning solvents have a composite 

vapor pressure of no more than 45 mm 

Hg (24.1 inches water) (40 CFR 

63.744(b) and (d)). The NESHAP 

specifies work practice standards for 

spray gun cleaning (e.g., cleaning a 

spray gun in an enclosed gun cleaning 

system) and flush cleaning operations 

(e.g., for flush cleaning events, empty 

used cleaning solvent into an enclosed 

container) (40 CFR 63.744(c) and (d)). 

Work practice measures are also 

specified for the storage and handling of 

solvents and solvent-laden materials 

(e.g., solvent-laden cloth, paper or other 

absorbent materials) (40 CFR 63.744(a)). 

Based on the technology review for 

cleaning operations, we did not identify 

any practices, processes or control 

technologies beyond those already 

required by the Aerospace NESHAP that 

could be transferred to the source 

category. A brief summary of the EPA’s 

findings in conducting its RTR review of 

cleaning operations follows. For a 

detailed discussion of the EPA’s 

findings, refer to the memorandum, 

Technology Review for Cleaning 

Operations in the Aerospace Source 

Category, January 2015, available in the 

docket for this action. 

In the technology review, we did not 

identify any improvements in add-on 

control technologies, other equipment 

or work practices and procedures since 

promulgation of the Aerospace 

NESHAP. The EPA identified one 

aerospace manufacturing and rework 

facility that routes the air flow from a 

spray booth to a carbon adsorption 

control device when performing spray 

gun cleaning and residual spray gun 

hand-wipe cleaning. We found that this 

was the same spray booth in which 

surface coating is performed, and it is 

not a spray booth dedicated to spray gun 

cleaning. Based on the results of the 

responses to the EPA’s 2011 information 

collection survey for other facilities, the 

EPA concluded that this practice could 

not be applied to the source category 

without impacting facility operations. 

First, very few facilities have carbon 

adsorbers controlling emissions from 

spray booths. Second, it is not always 

practical to move the spray gun cleaning 

operations into a spray booth without 

affecting the surface coating operations 

in that spray booth because of space 

limitations within the booth. 

The EPA also identified one aerospace 

manufacturing and rework facility that, 

for certain cleaning operations, uses a 

non-HAP solvent blend that has a vapor 

pressure of 36 mm Hg for certain 

cleaning operations; the facility does not 

use this solvent for all cleaning 

operations. The use of non-HAP 

cleaning solvent is already a compliance 

option that was considered in the 

development of the Aerospace NESHAP 

and is included in 40 CFR 63.744. 

Based on a finding of no new 

developments in practices, processes 

and control technologies in the 

technology review, we are not proposing 

any revisions to the Aerospace NESHAP 

standard requirements for cleaning 

operations pursuant to CAA section 

112(d)(6). For further discussion of the 

technology review results, refer to the 

memorandum, Technology Review for 

Cleaning Operations in the Aerospace 

Source Category, January 2015, available 

in the docket for this action. 

4. Chemical and Dry Media Blasting 

Depainting Operations 

At Aerospace Manufacturing and 

Rework Facilities, chemical and dry 

media blasting depainting operations 

remove unwanted or old surface 

coatings (e.g., primers, topcoats and 

specialty coatings) to prepare the 

surface for painting. As defined in the 

Aerospace NESHAP, a depainting 

operation means the use of a chemical 

agent, media blasting or any other 

technique to remove permanent coatings 

from the outer surface of an aerospace 

vehicle or components, excluding hand 

and mechanical sanding or other nonchemical removal processes that do not 

involve blast media or other 

mechanisms that would result in 

airborne particle movement at high 

velocity. The depainting operation 

includes washing of the aerospace 

vehicle or component to remove 

residual stripper, media or coating 

residue. Depainting is most often done 

in the rework of existing aircraft, but 

may also be done in limited 

circumstances in the manufacture of 

new aircraft. 

The liquid chemical agents (i.e., 

strippers) used to remove permanent 

coatings in the aerospace industry 

contain organic solvents. Organic HAP 

emissions from strippers occur from the 

evaporation of the chemical stripper 

during mixing, application and possibly 

during washing of the vehicle or 

component to remove residual stripper. 

The organic emissions from depainting 

operations that occur within a booth or 

hangar are typically captured and 

exhausted through a stack, although 

some emissions may be fugitive in 

nature (e.g., open containers of stripper). 

Inorganic HAP, typically metal 

compounds (e.g., compounds of lead, 

chromium or cadmium), can be emitted 

during dry media blasting if these 

compounds are present in the paint 

layer that is being removed. These 

inorganic HAP would be emitted as 

particulate matter as the dry media 

blasting removes the existing coating 

through abrasion. 

The Aerospace NESHAP restricts 

facilities to using organic HAPcontaining chemical strippers for only 

spot stripping and decal removal. The 

amount of stripper used for spot 

stripping and decal removal is limited 

to no more than 26 gallons of HAPcontaining chemical stripper (or 

alternatively 190 pounds of organic 

HAP) for each commercial aircraft, and 

50 gallons (or 365 pounds of organic 

HAP) for each military aircraft. As an 

alternative, facilities may use controls 

for organic HAP emissions from 


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34See the preamble to the proposed rule, 59 FR 

29216, June 6, 1994. 

35Sierra Club v. EPA, 479 F. 3d 875 (D.C. Cir. 

March 13, 2007). 

chemical depainting, and emissions 

must be reduced by 81 percent for 

controls installed before the effective 

date, and by 95 percent for controls 

installed on or after the effective date 

(40 CFR 63.746(b)(1) through (3) and 

(c)). 

For non-chemical depainting 

operations that generate inorganic HAP 

emissions from dry media blasting, the 

operation must be performed in an 

enclosed area or in a closed cycle 

depainting system and the air stream 

from the operation must pass through a 

dry filter system meeting a minimum 

efficiency specified in the rule, through 

a baghouse or through a waterwash 

system before being released to the 

atmosphere (40 CFR 63.746(b)(4)). 

Based on the technology review for 

depainting operations, we did not 

identify any practices, processes or 

control technologies that were not 

already required by the Aerospace 

NESHAP or considered in its 

development, nor did we identify any 

improvements to those practices, 

processes or control technologies that 

could be transferred and applied to this 

source category. A brief summary of the 

EPA’s findings in conducting the RTR 

review of chemical and dry media blast 

depainting operations follows. For a 

detailed discussion of the EPA’s 

findings, refer to the memorandum, 

Technology Review for Depainting 

Operations in the Aerospace Source 

Category, January 2015, available in the 

docket for this action. 

In reviewing Washington State’s 

records of permits for Aerospace 

Manufacturing and Rework Facilities, 

we identified a 2013 PSD permit 

amendment that requires the VOC vapor 

pressure of cleaning solvents and 

chemical strippers used in depainting 

operations to be less than 45 mm Hg. 

The Aerospace NESHAP does not 

prescribe vapor pressure limits to 

chemical depainting strippers, but 

instead has capture and control and 

volume usage limits for chemical 

depainting operations that use HAPcontaining chemical strippers. 

Otherwise, facilities must use non-HAP 

chemical strippers. Therefore, we 

believe that the Aerospace NESHAP is 

at least as stringent as the Washington 

State PSD permit requirements. 

Based on a finding of no new 

developments in practices, processes 

and control technologies in the 

technology review, we are not proposing 

to revise the Aerospace NESHAP 

standard requirements for chemical or 

dry media blast depainting operations 

pursuant to CAA section 112(d)(6). For 

further discussion of the technology 

review results, refer to the 

memorandum, Technology Review for 

Depainting Operations in the Aerospace 

Source Category, January 2015, available 

in the docket for this action. 

5. Waste Storage and Handling 

Operations 

At Aerospace Manufacturing and 

Rework Facilities, waste is produced 

primarily from cleaning, coating and 

depainting operations. Cleaning 

operations produce solvent-laden cloth 

and paper and spent solvent which can 

emit organic HAP from the evaporation 

of the solvents. Coating operations 

produce waste paint and waste solvent 

that also emit organic HAP through 

evaporation. 

Depainting operations can produce 

either a liquid or solid waste stream 

depending on the type of process used. 

Chemical depainting processes produce 

a waste sludge that consists of the 

stripper solution and paint residue. 

Emissions occur from the evaporation of 

the solvent from the stripper solution in 

the waste sludge. 

Blast depainting processes produce a 

solid waste stream that consists of paint 

chips and particles and spent blasting 

media. Emissions do not directly occur 

from this waste stream, although 

particulate emissions are generated 

during the blasting process. 

The requirements for waste storage 

and handling in the Aerospace NESHAP 

apply to each waste storage and 

handling operation, which is defined as 

the total of all waste handling and 

storage at the facility. In 40 CFR 63.748, 

the Aerospace NESHAP requires that all 

waste must be handled and transferred 

to or from containers, tanks, vats, 

vessels and piping systems in such a 

manner that spills are minimized. 

Because the EPA did not want to 

create possible conflicts over the 

handling of waste between the 

Aerospace NESHAP and regulations 

under the Resource Conservation and 

Recovery Act (RCRA) of 1976 (Pub. L. 

94–580), as implemented by 40 CFR 

parts 260 and 261, the Aerospace 

NESHAP specifically exempted wastes 

covered under the RCRA regulations.34

Per 40 CFR 63.741(e), all wastes that are 

determined to be hazardous wastes 

under RCRA as implemented by 40 CFR 

parts 260 and 261, and that are subject 

to RCRA requirements as implemented 

in 40 CFR parts 262 through 268, are 

exempt from the requirements of the 

Aerospace NESHAP. 

The practical effect of the provisions 

in 40 CFR 63.741(e) is that all HAPcontaining wastes generated by 

aerospace manufacturing and rework 

operations are subject to RCRA and are 

exempt from the requirements of 40 CFR 

63.748. Because all of these HAPcontaining wastes are covered under 

RCRA and exempt from 40 CFR 63.748, 

there is no need to do a technology 

review for the standards for handling 

and storage of waste. 

E. What other actions are we proposing? 

In addition to the proposed actions 

described above, we are proposing 

additional revisions. As stated 

previously in this preamble, the United 

States Court of Appeals for the District 

of Columbia Circuit found that the EPA 

had erred in establishing emissions 

standards for sources of HAP in the 

NESHAP for Brick and Structural Clay 

Products Manufacturing and Clay 

Ceramics Manufacturing, 67 FR 26690 

(May 16, 2003), and consequently 

vacated the rules.35 Among other things, 

the court found EPA erred by failing to 

regulate processes that emitted HAP, in 

some instances by establishing a MACT 

floor of ‘‘no control.’’ In this action we 

are proposing to correct the same error 

in the Aerospace NESHAP by proposing 

to remove the exemption for specialty 

coatings found at 40 CFR 63.741(f) and 

instead add limits for specialty coatings 

(including adhesives, adhesive bonding 

primers and sealants). 

1. Specialty Coating Application 

At Aerospace Manufacturing and 

Rework Facilities, specialty coatings are 

those coatings that have additional 

performance criteria for specific 

applications that are beyond the criteria 

for primers, topcoats and self-priming 

topcoats, although specialty coatings 

may still meet the definition of a primer 

or topcoat. These additional 

performance criteria may include, for 

example, temperature or fire resistance, 

substrate compatibility, antireflection, 

temporary protection or marking, 

sealant properties, adhesive properties, 

electrical insulation, lubrication or 

enhanced corrosion protection (40 CFR 

63.742). 

Specialty coatings contain a mixture 

of organic solvents and/or inorganic 

HAP. The organic HAP emissions from 

the application of specialty coatings 

occur from the evaporation of organic 

solvents during mixing, application and 

drying. Emissions of inorganic HAP 

from spray-applied coating operations, 

typically metal compounds (e.g., 

chromium, cadmium compounds), 

occur when particles do not adhere to 

the surface being coated (i.e., 


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overspray). The organic and inorganic 

emissions from coating application 

operations occur in large open areas, 

such as hangars or partially or fully 

enclosed spaces, such as within spray 

booths. 

The current Aerospace NESHAP 

explicitly excludes specialty coatings 

from meeting any control requirements, 

as specified in 40 CFR 63.741(f) and in 

40 CFR 63.742 (i.e., the definitions for 

‘‘exterior primer,’’ ‘‘primer,’’ and 

‘‘topcoat’’). Appendix A of the 

Aerospace NESHAP defines 59 separate 

categories of specialty coatings. 

Although the EPA did not include 

emission limitations for specialty 

coatings in the Aerospace NESHAP 

finalized in 1995 or in any subsequent 

amendments, the EPA included VOC 

content limits for the 59 categories of 

specialty coatings in the 1997 Aerospace 

CTG. The Aerospace CTG is intended to 

provide state and local air pollution 

control authorities with an information 

base, recommended emissions 

limitations and monitoring, 

recordkeeping and reporting 

requirements for proceeding with their 

analyses of reasonably available control 

technology (RACT) for their own 

regulations to reduce VOC emissions 

from aerospace surface coating 

operations. The Aerospace CTG 

includes presumptive VOC limits for 

specialty coating operations that are 

based on a review of the contemporary 

knowledge and data concerning the 

technology, impacts and costs 

associated with various emission 

control techniques. During their 

development, the specialty coating 

categories and VOC limits in the CTG 

were also subject to a period of public 

comment and review, and the final CTG 

categories and VOC limits were revised 

after proposal to reflect the EPA’s 

analysis of those comments on the 

proposed CTG. 

In this action, we are proposing to 

establish standards for specialty 

coatings. Based on a MACT analysis for 

specialty coatings, we are proposing to 

require aerospace manufacturing and 

rework specialty coating application 

operations to achieve organic HAP 

content limits that are equivalent to the 

VOC content limits for specialty 

coatings included in the Aerospace 

CTG. As discussed previously in section 

IV.E.1 of this preamble, the Aerospace 

CTG may be adopted by state and local 

agencies in nonattainment areas to assist 

them in meeting their state 

implementation plan requirements. Of 

the 109 facilities that reported the use 

of specialty coatings, 35 are in 

nonattainment areas and likely 

currently complying with the specialty 

coating limits in the Aerospace CTG. 

The remaining facilities would need to 

take action to comply with the specialty 

coating application operations limits. 

In the MACT analysis for specialty 

coatings, the EPA considered data 

provided in response to a 

comprehensive information collection 

request (ICR) sent out in February 2011 

and consulted the EPA’s RACT/BACT/ 

LAER Clearinghouse, the California 

Statewide Best Available Control 

Technology (BACT) Clearinghouse and 

regional and state regulations for 

sources of data on control technologies 

and limitations. We reviewed state rules 

to compare the VOC limits in those 

rules to the VOC limits in the Aerospace 

CTG. This review of state rules was in 

addition to a review of the database of 

responses to the 2011 ICR and the RBLC 

for information on add-on control 

technology or other equipment, work 

practices and procedures and process 

changes or pollution prevention 

alternatives not identified and 

considered during development of the 

Aerospace CTG, or improvements in the 

same since the CTG development. A 

brief summary of the EPA’s findings in 

conducting its MACT analysis of 

specialty coating application operations 

follows. For a detailed discussion of the 

EPA’s findings, refer to the 

memorandum, Maximum Achievable 

Control Technology for Specialty 

Coating Operations in the Aerospace 

Source Category, January 2015, available 

in the docket for this action. 

For specialty coatings, where there 

were sufficient data, the EPA compared 

the emissions for the best performing 

coatings with the Aerospace CTG limits. 

The results of this comparison showed 

that the CTG VOC limits were 

equivalent in performance to the best 

performing specialty coating. Therefore, 

we determined that the current 

Aerospace CTG limits represent MACT 

for specialty coatings. 

Based on the results of the MACT 

analysis, we determined that the VOC 

limits in the Aerospace CTG for 

specialty coatings are currently being 

achieved by about half of all operating 

sources subject to the Aerospace 

NESHAP. The facilities complying with 

the CTG limits for specialty coatings are 

located in ozone non-attainment areas 

where state VOC rules have been 

developed based on the Aerospace CTG. 

From our review of industry responses 

to the 2011 ICR, we determined that 

some facilities complying with these 

state VOC limits employ use of add-on 

control devices to reduce organic HAP 

emissions (i.e., thermal oxidizers and 

carbon adsorbers); however, these addon controls are not widely used in the 

source category. Other facilities achieve 

equivalent emission reductions without 

add-on controls by using coatings that 

meet the VOC content limits. 

Based on our review of state and 

regional regulations for specialty coating 

operations in the aerospace industry, we 

identified several cases in which limits 

are specified for certain specialty 

coating categories that are lower than 

the VOC content limits for the same 

specialty coating categories in the 

Aerospace CTG. These differences 

generally affect about one-quarter of the 

specialty coating categories (although 

each state or regional regulation may 

differ from the CTG in only a handful 

of categories), and the limits differ by 

less than 200 grams VOC per liter of 

coating. However, these state and 

regional rules and the Aerospace CTG 

differ in certain ways, such that the 

lower VOC limits in the state and 

regional rules do not represent a more 

stringent limit as compared to the 

Aerospace CTG. 

First, in many cases where a state rule 

has a lower VOC limit than the CTG, the 

state rule has also added coating 

categories with VOC limits equal to or 

higher than the CTG limits. For 

example, one state rule has a lower limit 

for fuel tank coatings, but has an 

additional category for ‘‘rapid cure’’ fuel 

tank coatings that is the same as the 

CTG VOC limit. 

Second, not all categories of specialty 

coatings are used at all Aerospace 

Manufacturing and Rework Facilities. 

For the specialty categories with more 

stringent VOC limits, the EPA does not 

have data to confirm that facilities exist 

in those jurisdictions that are using 

those coatings and actually have to 

comply with the more stringent VOC 

limits. These data on facilities actually 

using coatings subject to these more 

stringent limits would be needed to 

confirm that these more stringent limits 

constitute the MACT floor according to 

section 112(d)(3) of the CAA. 

Finally, many of the areas with more 

stringent VOC limits than in the CTG 

have climates that are warmer and drier 

than in most other parts of the United 

States, and this type of climate is more 

conducive to the use of low-VOC 

coatings because it helps promote 

expeditious curing of the coatings under 

ambient conditions. In cooler and more 

humid areas, the coatings require the 

use of a solvent carrier and/or thermal 

curing. The Aerospace NESHAP and 

CTG, on the other hand, must establish 

HAP and VOC limits that are applicable 

across the United States. It is not 

practical to establish MACT limits for 

coatings based on regional climate 

differences for this source category. 


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Based on the issues noted above, the 

EPA concludes that the noted 

differences between the state and 

regional rules and the Aerospace CTG 

limits do not constitute more stringent 

limits compared to those in the 

Aerospace CTG. The EPA does not have 

sufficient data to determine whether 

these differences in VOC limits, 

compared to the limits in the Aerospace 

CTG, actually constitute MACT. 

Therefore, the EPA is specifically 

soliciting comment and additional data 

on the differences noted between state 

and regional rules and the aerospace 

CTG. 

Based on its analysis, the EPA is 

proposing the MACT floor for specialty 

coatings to be organic HAP content 

limits equal to the VOC limits specified 

in the Aerospace CTG for specialty 

coatings. Additionally, the low-volume 

exemption provisions in the current 

Aerospace NESHAP for primers, 

topcoats and chemical milling maskants 

may be used for specialty coatings. The 

EPA has not identified any options more 

stringent than the MACT floor as 

documented in the review of specialty 

coatings discussed earlier in this 

section, so the proposed organic HAP 

content limits are equal to the MACT 

floor VOC content limits. The EPA is 

proposing this MACT floor based on the 

fact that these VOC limits are currently 

being achieved by at least 12 percent of 

the operating facilities in a total 

population of 109 operating aerospace 

and rework facilities that reported using 

specialty coatings in the 2011 ICR. For 

more information on the MACT floor 

analysis, please refer to the 

memorandum, Maximum Achievable 

Control Technology for Specialty 

Coating Operations in the Aerospace 

Source Category, January 2015, available 

in the docket for this action. 

In reviewing the state and district 

VOC rules, the EPA determined that the 

aerospace surface coating rules in many 

of the California district rules, in 

addition to the requirement to meet 

VOC limits, require that all sprayapplied coating operations use highefficiency application equipment (i.e., 

HVLP, electrostatic spray or an 

equivalent). This requirement is more 

stringent than the model rule found in 

the Aerospace CTG, which exempts 

specialty coatings from the requirement 

to use high-efficiency application 

equipment. The California rules 

examined by the EPA require the use of 

high-efficiency application equipment 

for all spray applied coatings, unless an 

add-on control system was used, or 

certain other exemptions apply. Other 

state rules that follow the CTG require 

high-efficiency application methods 

only for primer and topcoat application 

operations. The facilities located in 

California that are required to use highefficiency application equipment for 

specialty coatings constitute the MACT 

floor for the application of these 

coatings. This determination is based on 

the fact that at least 11 facilities in 

California’s air pollution control 

districts are currently subject to district 

rules that require high-efficiency 

application equipment for all coating 

operations, including specialty coatings. 

Therefore, the EPA is proposing that 

specialty coatings be subject to the same 

application requirements in 40 CFR 

63.745(f) as primers and topcoats. 

Compared to conventional spray 

application methods, high-efficiency 

application methods, such as HVLP 

spray guns or electrostatic deposition, 

can achieve HAP and VOC emission 

reductions because of reduced coating 

consumption that results from reduced 

coating overspray. The EPA has not 

identified any control options more 

stringent than the use of high-efficiency 

application methods for spray-applied 

coating operations. 

In our review of the RBLC, we did not 

identify any control options for 

aerospace specialty surface coating 

operations that were not already 

reflected in the VOC content limits in 

the Aerospace CTG. However, we 

identified one facility in the state of 

Washington for which a BACT analysis 

was completed in September 2014, for 

constructing new buildings needed for 

producing new models of large 

commercial airplanes, including the 

building and surface coating of 

composite aircraft wings. The BACT 

analysis described the facility as 

currently using HVLP spraying and 

electrostatic airless and modified highefficiency air-assisted airless spray 

equipment in all spray applied surface 

coating operations. The BACT analysis 

concluded that there were no 

demonstrations of add-on controls at 

facilities performing surface coating 

comparable to large commercial aircraft 

wing components. 

In our review of Washington State’s 

record of permits, we determined that 

the current PSD permit for this facility 

identified BACT for VOC from coating 

operations to be the equivalent of 

complying with ‘‘all applicable VOC 

emission standards of the Aerospace 

NESHAP.’’ The PSD permit for the 

facility did not consider add-on control 

technologies to be BACT after taking 

into account energy, environmental and 

economic impacts. Based on this 

information from the RBLC and the 

Washington State BACT analysis, we 

determined that add-on control 

techniques would not be MACT for 

specialty coating application operations 

for the aerospace industry. 

Instead, MACT is being proposed as 

the use of low-HAP coatings (with HAP 

content limits equal to the VOC content 

limits in the Aerospace CTG) and highefficiency application methods for 

spray-applied coating operations. As the 

EPA did with primers and top coats in 

the current NESHAP, the EPA is 

proposing to use VOC limits that are 

currently in effect as the basis for 

proposed organic HAP limits. 

The EPA is also proposing to establish 

MACT to limit emissions of inorganic 

HAP from spray-applied specialty 

coatings that contain inorganic HAP. 

The predominant method used to 

control inorganic HAP emissions from 

all spray-applied coating operations 

(including specialty coatings) is the use 

of a spray booth with a particulate filter, 

which generally achieves a high (i.e., 

greater than 99 percent) control 

efficiency. The Aerospace NESHAP 

currently requires the use of spray 

booths with filters meeting minimum 

efficiency requirements for the spray 

application of primers and topcoats that 

contain inorganic HAP. Based on the 

results of the 2011 ICR, the EPA has 

determined that the vast majority of 

spray-applied specialty coatings are 

currently applied in spray booths. It is 

likely that these specialty coatings are 

applied in the same spray booths as 

primers and topcoats, or at least in spray 

booths that are very similar to those 

used for primer and topcoat operations. 

Therefore, the same inorganic HAP 

emission limitations that are applied to 

primer and topcoat operations should 

also be applicable to specialty coating 

operations, and the EPA is proposing to 

extend these limitations to specialty 

coating operations. The EPA has not 

identified any control options more 

stringent than the use of spray booths 

with high-efficiency filters to control 

inorganic HAP emissions from sprayapplied coating operations. 

In summary, the EPA is proposing to 

add a requirement to the Aerospace 

NESHAP that Aerospace Manufacturing 

and Rework Facilities comply with 

organic HAP or VOC content limits for 

specialty coatings that are equal to the 

VOC content limits specified in the 

Aerospace CTG. The EPA is also 

proposing that specialty coating 

application operations be subject to the 

same application equipment 

requirements in 40 CFR 63.745(f), and 

the standards for inorganic HAP 

emissions in 40 CFR 63.745(g) that 

apply to primer and topcoat application 

operations. We request comment on our 

analysis and supporting info on any 


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other practices that may be used to limit 

emissions from specialty coatings. 

The EPA believes that the proposed 

HAP and VOC content limits for 

specialty coatings are achievable 

because they are based on the VOC 

content limits in the Aerospace CTG, 

which have been adopted in many state 

and local VOC rules. In the 

development of these proposed 

amendments, the EPA made repeated 

efforts to reach out to and solicit input 

from aerospace manufacturers on the 

coating performance and reformulation 

challenges, if any, presented by 

complying with specialty coating limits 

based on the current CTG. However, the 

information presented so far has been 

only anecdotal, and not for the full 

range of specialty coating categories in 

the CTG. 

Therefore, the EPA is specifically 

soliciting comment and additional data 

on any changes needed to the 

definitions of specialty coating 

categories and the proposed organic 

HAP and VOC limits. The EPA will 

consider comments on changes to the 

definitions of specialty coating 

categories that may be needed to clarify 

the scope of each of the individual 

specialized coating categories, based on 

industry experience, including 

complying with those categories in rules 

derived from the Aerospace CTG. The 

EPA will consider data and information 

on specific cases (not just general 

examples) of specialty coatings that 

could not meet the current definitions of 

the specialty coating categories or the 

proposed organic HAP or VOC content 

limits for those categories. Please 

provide with your comments 

information on the following: The 

annual volume of the coating used, the 

container size, the container type, the 

military specification or FAA AD that 

applies, the specialty category that 

applies, documentation of the organic 

HAP or VOC content of the coating and 

suggested changes to category 

definitions (if applicable and feasible) 

that would include the coating in a 

more appropriate category with a higher 

HAP or VOC limit. The EPA will 

consider any submitted data that 

supports a comment that a specific 

coating cannot meet the proposed 

organic HAP or VOC content limit for a 

particular specialty coating category. 

The estimated costs, emission 

reductions, other (non-air) 

environmental impacts and energy 

impacts associated with the proposed 

regulation of specialty coatings are 

presented in section V of this preamble. 

2. Electronic Reporting Requirements 

In this proposal, the EPA is describing 

a process to increase the ease and 

efficiency of performance test data 

submittal while improving data 

accessibility. Specifically, the EPA is 

proposing that owners and operators of 

Aerospace Manufacturing and Rework 

Facilities submit electronic copies of 

required performance test and 

performance evaluation reports by 

direct computer-to-computer electronic 

transfer using EPA-provided software. 

The direct computer-to-computer 

electronic transfer is accomplished 

through the EPA’s Central Data 

Exchange (CDX) using the Compliance 

and Emissions Data Reporting Interface 

(CEDRI). The CDX is the EPA’s portal 

for submittal of electronic data. The 

EPA-provided software is called the 

Electronic Reporting Tool (ERT), which 

is used to generate electronic reports of 

performance tests and evaluations. The 

ERT generates an electronic report 

package which will be submitted using 

the CEDRI. The submitted report 

package will be stored in the CDX 

archive (the official copy of record) and 

the EPA’s public database called 

WebFIRE. The WebFIRE database was 

constructed to store performance test 

data for use in developing emissions 

factors. All stakeholders would have 

access to all reports and data in 

WebFIRE and accessing these reports 

and data will be very straightforward 

and easy (see the WebFIRE Report 

Search and Retrieval link at http://

cfpub.epa.gov/webfire/index.cfm?

action=fire.searchERTSubmission). A 

description of the WebFIRE database is 

available at http://cfpub.epa.gov/

oarweb/index.cfm?action=fire.main. A 

description of the ERT and instructions 

for using ERT can be found at http://

www.epa.gov/ttn/chief/ert/ert_tool.html. 

CEDRI can be accessed through the CDX 

Web site (www.epa.gov/cdx). 

The proposal to submit performance 

test data electronically to the EPA 

would apply only to those performance 

tests conducted using test methods that 

will be supported by the ERT. The ERT 

contains a specific electronic data entry 

form for most of the commonly used 

EPA reference methods. A listing of the 

pollutants and test methods supported 

by the ERT is available at http://

www.epa.gov/ttn/chief/ert/index.html. 

We believe that industry would benefit 

from this proposed approach to 

electronic data submittal. Specifically, 

by using this approach, industry would 

save time in the performance test 

submittal process. Additionally, the 

standardized format that the ERT uses 

allows sources to create a more 

complete test report resulting in less 

potential failure to include all data 

elements required to be submitted. Also 

through this proposal, industry may 

only need to submit a report once to 

meet the requirements of the applicable 

subpart because stakeholders can 

readily access these reports from the 

WebFIRE database. This also would 

benefit industry by cutting back on 

recordkeeping costs as the performance 

test reports that are submitted to the 

EPA using CEDRI are no longer required 

to be retained in hard copy, thereby 

reducing staff time needed to coordinate 

these records. Another benefit to 

industry is that, because the EPA would 

already have performance test data in 

hand, industry would be subject to 

fewer or less substantial data collection 

requests from EPA in conjunction with 

required future residual risk 

assessments or technology reviews. This 

would result in a decrease in industry 

staff time needed to respond to data 

collection requests. 

State, local and tribal air pollution 

control agencies (S/L/Ts) may also 

benefit from having electronic versions 

of the reports they are now receiving. 

For example, S/L/Ts may be able to 

conduct a more streamlined and 

accurate review of electronic data 

submitted to them. The ERT would 

allow for an electronic review process, 

rather than a manual data assessment, 

which will make review and evaluation 

of the source provided data and 

calculations easier and more efficient. In 

addition, the public will benefit from 

electronic reporting of emissions data 

because the electronic data will be 

easier for the public to access. How the 

air emissions data are collected, 

accessed and reviewed will be more 

transparent for all stakeholders. 

Further, the EPA must have 

performance test data to conduct 

effective reviews of CAA sections 112 

and 129 standards, as well as for many 

other purposes including compliance 

determinations, emissions factor 

development and annual emissions rate 

determinations. In conducting these 

required reviews, the EPA has found it 

ineffective and time consuming, not 

only for the EPA, but also for regulatory 

agencies and source owners and 

operators, to locate, collect and submit 

performance test data because of varied 

locations for data storage and varied 

data storage methods. In recent years, 

though, stack testing firms have 

typically collected performance test data 

in electronic format, making it possible 

to move to an electronic data submittal 

system that would increase the ease and 

efficiency of data submittal and improve 

data accessibility. 


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One major advantage of the proposed 

submittal of performance test data 

through the ERT is a standardized 

method to compile and store much of 

the documentation required to be 

reported by this rule. Another advantage 

is that the ERT clearly states what 

testing information would be required. 

Another important proposed benefit of 

submitting these data to the EPA at the 

time the source test is conducted is that 

it should substantially reduce the effort 

involved in data collection activities in 

the future. When the EPA has 

performance test data in hand, the EPA 

will be able to conduct fewer or less 

substantial data collection requests in 

conjunction with future required 

residual risk assessments or technology 

reviews. This would result in a reduced 

burden on both affected facilities (in 

terms of reduced staff time to respond 

to data collection requests) and the EPA 

(in terms of preparing and distributing 

data collection requests and assessing 

the results). 

Finally, another benefit of the 

proposed data submittal to WebFIRE 

electronically is that these data would 

greatly improve the overall quality of 

existing and new emissions factors by 

supplementing the pool of emissions 

test data for establishing emissions 

factors and by ensuring that the factors 

are more representative of current 

industry operational procedures. A 

common complaint heard from industry 

and regulators is that emissions factors 

are outdated or not representative of a 

particular source category. With timely 

receipt and incorporation of data from 

most performance tests, the EPA would 

be able to ensure that emissions factors, 

when updated, represent the most 

current range of operational practices. 

In summary, in addition to supporting 

regulation development, control strategy 

development and other air pollution 

control activities, having an electronic 

database populated with performance 

test data would save industry, state, 

local, tribal agencies and the EPA 

significant time, money and effort while 

also improving the quality of emissions 

inventories and, as a result, air quality 

regulations. 

3. Startup, Shutdown and Malfunction 

Requirements 

In its 2008 decision in Sierra Club v. 

EPA, 551 F.3d 1019 (D.C. Cir. 2008), 

cert. denied, 130 S. Ct. 1735 (U.S. 2010), 

the United States Court of Appeals for 

the District of Columbia Circuit vacated 

portions of two provisions in the EPA’s 

CAA section 112 regulations governing 

the emissions of HAP during periods of 

SSM. Specifically, the court vacated the 

SSM exemption contained in 40 CFR 

63.6(f)(1) and (h)(1), holding that under 

section 302(k) of the CAA, emissions 

standards or limitations must be 

continuous in nature and that the SSM 

exemption violates the CAA’s 

requirement that some section 112 

standards apply continuously. 

We are proposing the elimination of 

the SSM exemption in this rule. 

Consistent with Sierra Club v. EPA, we 

are proposing changes so that standards 

in this rule would apply at all times. We 

are also proposing several revisions to 

Table 1 to subpart GG of Part 63 (the 

General Provisions Applicability Table, 

hereafter referred to as the ‘‘General 

Provisions table’’) as explained in more 

detail below. For example, we are 

proposing to eliminate the incorporation 

of the General Provisions’ requirement 

that the source develop an SSM plan. 

We also are proposing to eliminate and 

revise certain recordkeeping and 

reporting requirements related to the 

SSM exemption as further described 

below. 

The EPA has attempted to ensure that 

the provisions we are proposing to 

eliminate are inappropriate, 

unnecessary or redundant in the 

absence of the SSM exemption. We are 

specifically seeking comment on 

whether we have successfully done so. 

In proposing the standards in this 

rule, the EPA has taken into account 

startup and shutdown periods and, for 

the reasons explained below, has not 

proposed alternate standards for those 

periods. 

Periods of startup, normal operations 

and shutdown are all predictable and 

routine aspects of a source’s operations. 

Malfunctions, in contrast, are neither 

predictable nor routine. Instead they 

are, by definition sudden, infrequent 

and not reasonably preventable failures 

of emissions control, process or 

monitoring equipment. The EPA 

interprets CAA section 112 as not 

requiring emissions that occur during 

periods of malfunction to be factored 

into development of CAA section 112 

standards. Under section 112, emissions 

standards for new sources must be no 

less stringent than the level ‘‘achieved’’ 

by the best controlled similar source 

and, for existing sources, generally must 

be no less stringent than the average 

emission limitation ‘‘achieved’’ by the 

best performing 12 percent of sources in 

the category. There is nothing in section 

112 that directs the agency to consider 

malfunctions in determining the level 

‘‘achieved’’ by the best performing 

sources when setting emission 

standards. As the D.C. Circuit has 

recognized, the phrase ‘‘average 

emissions limitation achieved by the 

best performing 12 percent of’’ sources 

‘‘says nothing about how the 

performance of the best units is to be 

calculated.’’ Nat’l Ass’n of Clean Water 

Agencies v. EPA, 734 F.3d 1115, 1141 

(D.C. Cir. 2013). While the EPA 

accounts for variability in setting 

emissions standards, nothing in CAA 

section 112 requires the agency to 

consider malfunctions as part of that 

analysis. A malfunction should not be 

treated in the same manner as the type 

of variation in performance that occurs 

during routine operations of a source. A 

malfunction is a failure of the source to 

perform in a ‘‘normal or usual manner’’ 

and no statutory language compels the 

EPA to consider such events in setting 

CAA section 112 standards. 

Further, accounting for malfunctions 

in setting emission standards would be 

difficult, if not impossible, given the 

myriad different types of malfunctions 

that can occur across all sources in the 

category and given the difficulties 

associated with predicting or accounting 

for the frequency, degree and duration 

of various malfunctions that might 

occur. As a result, the performance of 

units that are malfunctioning is not 

‘‘reasonably’’ foreseeable. See, e.g. 

Sierra Club v. EPA, 167 F.3d 658, 662 

(D.C. Cir. 1999) (‘‘The EPA typically has 

wide latitude in determining the extent 

of data-gathering necessary to solve a 

problem. We generally defer to an 

agency’s decision to proceed on the 

basis of imperfect scientific information, 

rather than to ‘invest the resources to 

conduct the perfect study.’ ’’) See also, 

Weyerhaeuser v. Costle, 590 F.2d 1011, 

1058 (D.C. Cir. 1978) (‘‘In the nature of 

things, no general limit, individual 

permit, or even any upset provision can 

anticipate all upset situations. After a 

certain point, the transgression of 

regulatory limits caused by 

‘uncontrollable acts of third parties,’ 

such as strikes, sabotage, operator 

intoxication or insanity and a variety of 

other eventualities, must be a matter for 

the administrative exercise of case-bycase enforcement discretion, not for 

specification in advance by 

regulation.’’). In addition, emissions 

during a malfunction event can be 

significantly higher than emissions at 

any other time of source operation. For 

example, if an air pollution control 

device with 99-percent removal goes offline as a result of a malfunction (as 

might happen if, for example, the bags 

in a baghouse catch fire) and the 

emission unit is a steady-state type unit 

that would take days to shut down, the 

source would go from 99-percent 

control to zero control until the control 

device was repaired. The source’s 

emissions during the malfunction 


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36The court’s reasoning in NRDC v. EPA focuses 

on civil judicial actions. The Court noted that 

‘‘EPA’s ability to determine whether penalties 

should be assessed for Clean Air Act violations 

extends only to administrative penalties, not to civil 

penalties imposed by a court.’’ Id. 

37Although the NRDC v. EPA case does not 

address the EPA’s authority to establish an 

affirmative defense to penalties that is available in 

administrative enforcement actions, the EPA is not 

including such an affirmative defense in the 

proposed rule. As explained above, such an 

affirmative defense is not necessary. Moreover, 

assessment of penalties for violations caused by 

malfunctions in administrative proceedings and 

judicial proceedings should be consistent. CF. CAA 

section 113(e) (requiring both the Administrator 

and the court to take specified criteria into account 

when assessing penalties). 

would be 100 times higher than during 

normal operations and the emissions 

over a 4-day malfunction period would 

exceed the annual emissions of the 

source during normal operations. As 

this example illustrates, accounting for 

malfunctions could lead to standards 

that are not reflective of (and 

significantly less stringent than) levels 

that are achieved by a well-performing 

non-malfunctioning source. It is 

reasonable to interpret CAA section 112 

to avoid such a result. The EPA’s 

approach to malfunctions is consistent 

with CAA section 112 and is a 

reasonable interpretation of the statute. 

In the event that a source fails to 

comply with the applicable CAA section 

112 standards as a result of a 

malfunction event, the EPA would 

determine an appropriate response 

based on, among other things, the good 

faith efforts of the source to minimize 

emissions during malfunction periods, 

including preventative and corrective 

actions, as well as root cause analyses 

to ascertain and rectify excess 

emissions. The EPA would also 

consider whether the source’s failure to 

comply with the CAA section 112 

standard was, in fact, sudden, 

infrequent, not reasonably preventable 

and was not instead caused in part by 

poor maintenance or careless operation. 

If the EPA determines that an 

enforcement action against a source for 

violation of an emission standard is 

warranted, the source can raise any and 

all defenses in that enforcement action 

and the federal district court will 

determine what, if any, relief is 

appropriate. The same is true for citizen 

enforcement actions. Similarly, the 

presiding officer in an administrative 

proceeding can consider any defense 

raised and determine whether 

administrative penalties are appropriate. 

In summary, the EPA interpretation of 

the CAA and, in particular, CAA section 

112 is reasonable and encourages 

practices that will avoid malfunctions. 

Administrative and judicial procedures 

for addressing exceedances of the 

standards fully recognize that violations 

may occur despite good faith efforts to 

comply and can accommodate those 

situations. 

In several prior CAA section 112 

rules, the EPA had included an 

affirmative defense to civil penalties for 

violations caused by malfunctions in an 

effort to create a system that 

incorporates some flexibility, 

recognizing that there is a tension, 

inherent in many types of air regulation, 

to ensure adequate compliance while 

simultaneously recognizing that despite 

the most diligent of efforts, emission 

standards may be violated under 

circumstances entirely beyond the 

control of the source. Although the EPA 

recognized that its case-by-case 

enforcement discretion provides 

sufficient flexibility in these 

circumstances, it included the 

affirmative defense to provide a more 

formalized approach and more 

regulatory clarity. See Weyerhaeuser Co. 

v. Costle, 590 F.2d 1011, 1057–58 (D.C. 

Cir. 1978) (holding that an informal 

case-by-case enforcement discretion 

approach is adequate); but see Marathon 

Oil Co. v. EPA, 564 F.2d 1253, 1272–73 

(9th Cir. 1977) (requiring a more 

formalized approach to consideration of 

‘‘upsets beyond the control of the permit 

holder’’). Under the EPA’s regulatory 

affirmative defense provisions, if a 

source could demonstrate in a judicial 

or administrative proceeding that it had 

met the requirements of the affirmative 

defense in the regulation, civil penalties 

would not be assessed. Recently, the 

United States Court of Appeals for the 

District of Columbia Circuit vacated an 

affirmative defense in one of the EPA’s 

CAA section 112 regulations. NRDC v. 

EPA, 749 F.3d 1055 (D.C. Cir., 2014) 

(vacating affirmative defense provisions 

in CAA section 112 rule establishing 

emission standards for Portland cement 

kilns). The court found that the EPA 

lacked authority to establish an 

affirmative defense for private civil suits 

and held that under the CAA, the 

authority to determine civil penalty 

amounts in such cases lies exclusively 

with the courts, not the EPA. 

Specifically, the court found: ‘‘As the 

language of the statute makes clear, the 

courts determine, on a case-by-case 

basis, whether civil penalties are 

‘appropriate.’’’ See NRDC, 2014 U.S. 

App. LEXIS 7281 at *21 (‘‘[U]nder this 

statute, deciding whether penalties are 

‘appropriate’ in a given private civil suit 

is a job for the courts, not EPA.’’).36 In 

light of NRDC, the EPA is not including 

a regulatory affirmative defense 

provision in the proposed rule. As 

explained above, if a source is unable to 

comply with emissions standards as a 

result of a malfunction, the EPA may 

use its case-by-case enforcement 

discretion to provide flexibility, as 

appropriate. Further, as the United 

States Court of Appeals for the District 

of Columbia Circuit recognized, in an 

EPA or citizen enforcement action, the 

court has the discretion to consider any 

defense raised and determine whether 

penalties are appropriate. Cf. NRDC, 

2014 U.S. App. LEXIS 7281 at *24 

(arguments that violation were caused 

by unavoidable technology failure can 

be made to the courts in future civil 

cases when the issue arises). The same 

is true for the presiding officer in EPA 

administrative enforcement actions.37

a. 40 CFR 63.743(e) General Duty 

We are proposing to revise the entry 

in the General Provisions table for 40 

CFR 63.6(e)(1)(i) by changing the ‘‘yes’’ 

in column 2 to a ‘‘no.’’ Section 

63.6(e)(1)(i) describes the general duty 

to minimize emissions. Some of the 

language in that section is no longer 

necessary or appropriate in light of the 

elimination of the SSM exemption. We 

are proposing instead to add general 

duty regulatory text at 40 CFR 63.743(e) 

that reflects the general duty to 

minimize emissions while eliminating 

the reference to periods covered by an 

SSM exemption. The current language 

in 40 CFR 63.6(e)(1)(i) characterizes 

what the general duty entails during 

periods of SSM. With the elimination of 

the SSM exemption, there is no need to 

differentiate between normal operations, 

startup and shutdown and malfunction 

events in describing the general duty. 

Therefore the language the EPA is 

proposing for 40 CFR 63.743(e) does not 

include that language from 40 CFR 

63.6(e)(1). 

We are also proposing to revise the 

General Provisions table entry for 40 

CFR 63.6(e)(1)(ii) by changing the ‘‘yes’’ 

in column 2 to a ‘‘no.’’ Section 

63.6(e)(1)(ii) imposes requirements that 

are not necessary with the elimination 

of the SSM exemption or are redundant 

with the general duty requirement being 

added at 40 CFR 63.743(e). 

b. SSM Plan 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.6(e)(3) by changing the ‘‘yes’’ in 

column 2 to a ‘‘no.’’ Generally, these 

paragraphs require development of an 

SSM plan and specify SSM 

recordkeeping and reporting 

requirements related to the SSM plan. 

As noted, the EPA is proposing to 

remove the SSM exemptions. Therefore, 

affected units will be subject to an 


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emission standard during such events. 

The applicability of a standard during 

such events will ensure that sources 

have ample incentive to plan for and 

achieve compliance and, thus, the SSM 

plan requirements are no longer 

necessary. 

c. Compliance With Standards 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.6(f)(1) by changing the ‘‘yes’’ in 

column 2 to a ‘‘no.’’ The current 

language of 40 CFR 63.6(f)(1) exempts 

sources from non-opacity standards 

during periods of SSM. As discussed 

above, the court in Sierra Club v. EPA 

vacated the exemptions contained in 

this provision and held that the CAA 

requires that some CAA section 112 

standards apply continuously. 

Consistent with Sierra Club, the EPA is 

proposing to revise some standards in 

this rule to apply at all times. 

d. 40 CFR 63.749(j) Performance Testing 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.7(e)(1) by changing the ‘‘yes’’ in 

column 2 to a ‘‘no.’’ Section 63.7(e)(1) 

describes performance testing 

requirements. The EPA is instead 

proposing to add a performance testing 

requirement at 40 CFR 63.749(j). The 

performance testing requirements we 

are proposing to add differ from the 

General Provisions performance testing 

provisions in several respects. The 

regulatory text does not include the 

language in 40 CFR 63.7(e)(1) that 

restated the SSM exemption and 

language that precluded startup and 

shutdown periods from being 

considered ‘‘representative’’ for 

purposes of performance testing. The 

proposed performance testing 

provisions will specify that performance 

testing of controls must be conducted 

during representative operating 

conditions of the applicable source, and 

may not take place during startup, 

shutdown or malfunction of the 

applicable controlled surface coating 

operations, controlled chemical milling 

maskant application operations or 

controlled chemical depainting 

operations. As in 40 CFR 63.7(e)(1), 

performance tests conducted under this 

subpart should not be conducted during 

malfunctions because conditions during 

malfunctions are often not 

representative of normal operating 

conditions. The EPA is proposing to add 

language that requires the owner or 

operator to record the process 

information that is necessary to 

document operating conditions during 

the test and include in such record an 

explanation to support that such 

conditions represent normal operation. 

Section 63.7(e) requires that the owner 

or operator make available to the 

Administrator such records ‘‘as may be 

necessary to determine the condition of 

the performance test’’ available to the 

Administrator upon request, but does 

not specifically require the information 

to be recorded. The regulatory text the 

EPA is proposing to add to this 

provision builds on that requirement 

and makes explicit the requirement to 

record the information. 

e. Monitoring 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.8(c)(1)(i) and (iii) by changing 

the ‘‘yes’’ in column 2 to a ‘‘no.’’ The 

cross-references to the general duty and 

SSM plan requirements in those 

subparagraphs are not necessary in light 

of other requirements of 40 CFR 63.8 

that require good air pollution control 

practices (40 CFR 63.8(c)(1)) and that set 

out the requirements of a quality control 

program for monitoring equipment (40 

CFR 63.8(d)). 

f. 40 CFR 63.752(a) Recordkeeping 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.10(b)(2)(i) by changing the ‘‘yes’’ 

in column 2 to a ‘‘no.’’ Section 

63.10(b)(2)(i) describes the 

recordkeeping requirements during 

startup and shutdown. These recording 

provisions are no longer necessary 

because the EPA is proposing that 

recordkeeping and reporting applicable 

to normal operations will apply to 

startup and shutdown. In the absence of 

special provisions applicable to startup 

and shutdown, such as a startup and 

shutdown plan, there is no reason to 

retain additional recordkeeping for 

startup and shutdown periods. 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.10(b)(2)(ii) by changing the 

‘‘yes’’ in column 2 to a ‘‘no.’’ Section 

63.10(b)(2)(ii) describes the 

recordkeeping requirements during a 

malfunction. The EPA is proposing to 

add such requirements to 40 CFR 

63.752(a). The regulatory text we are 

proposing to add differs from the 

General Provisions it is replacing in that 

the General Provisions requires the 

creation and retention of a record of the 

occurrence and duration of each 

malfunction of process, air pollution 

control and monitoring equipment. The 

EPA is proposing that this requirement 

apply to any failure to meet an 

applicable standard and is requiring that 

the source record the date, time and 

duration of the failure rather than the 

‘‘occurrence.’’ The EPA is also 

proposing to add to 40 CFR 63.752(a) a 

requirement that sources keep records 

that include a list of the affected source 

or equipment and actions taken to 

minimize emissions, an estimate of the 

quantity of each regulated pollutant 

emitted over the standard for which the 

source failed to meet the standard and 

a description of the method used to 

estimate the emissions. Examples of 

such methods would include mass 

balance calculations, measurements 

when available or engineering judgment 

based on known process parameters 

(e.g., coating HAP content and 

application rate or control device 

efficiencies). The EPA is proposing to 

require that sources keep records of this 

information to ensure that there is 

adequate information to allow the EPA 

to determine the severity of any failure 

to meet a standard and to provide data 

that may document how the source met 

the general duty to minimize emissions 

when the source has failed to meet an 

applicable standard. 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.10(b)(2)(iv) by changing the 

‘‘yes’’ in column 2 to a ‘‘no.’’ When 

applicable, the provision requires 

sources to record actions taken during 

SSM events when actions were 

inconsistent with their SSM plan. The 

requirement is no longer appropriate 

because SSM plans will no longer be 

required. The requirement previously 

applicable under 40 CFR 

63.10(b)(2)(iv)(B) to record actions to 

minimize emissions and record 

corrective actions is now applicable by 

reference to 40 CFR 63.752(a). 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.10(b)(2)(v) by changing the 

‘‘yes’’ in column 2 to a ‘‘no.’’ When 

applicable, the provision requires 

sources to record actions taken during 

SSM events to show that actions taken 

were consistent with their SSM plan. 

The requirement is no longer 

appropriate because SSM plans will no 

longer be required. 

g. 40 CFR 63.753 Reporting 

We are proposing to revise the 

General Provisions table entry for 40 

CFR 63.10(d)(5) by changing the ‘‘yes’’ 

in column 2 to a ‘‘no.’’ Section 

63.10(d)(5) describes the reporting 

requirements for startups, shutdowns 

and malfunctions. To replace the 

General Provisions reporting 

requirement, the EPA is proposing to 

add reporting requirements to 40 CFR 

63.753(a). The replacement language 

added to 40 CFR 63.753(a) differs from 

the General Provisions requirement in 

that it eliminates periodic SSM reports 


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as a stand-alone report. We are 

proposing language that requires 

sources that fail to meet an applicable 

standard at any time to report the 

information concerning such events in 

the semi-annual reporting period 

already required under this rule. We are 

proposing that the report must contain 

the number, date, time, duration and the 

cause of such events (including 

unknown cause, if applicable), a list of 

the affected source or equipment, an 

estimate of the quantity of each 

regulated pollutant emitted over any 

emission limit and a description of the 

method used to estimate the emissions. 

Examples of such methods would 

include mass balance calculations, 

measurements when available or 

engineering judgment based on known 

process parameters (e.g., coating HAP 

content and application rates and 

control device efficiencies). The EPA is 

proposing this requirement to ensure 

that there is adequate information to 

determine compliance, to allow the EPA 

to determine the severity of the failure 

to meet an applicable standard and to 

provide data that may document how 

the source met the general duty to 

minimize emissions during a failure to 

meet an applicable standard. 

We would no longer require owners 

or operators to determine whether 

actions taken to correct a malfunction 

are consistent with an SSM plan, 

because plans would no longer be 

required. The proposed amendments 

would, therefore, eliminate the cross 

reference to 40 CFR 63.10(d)(5)(i) that 

contains the description of the 

previously required SSM report format 

and submittal schedule from this 

section. These specifications would be 

no longer necessary because the events 

would be reported in otherwise required 

reports with similar format and 

submittal requirements. 

As discussed above, we are proposing 

to revise the General Provisions table 

entry for 40 CFR 63.10(d)(5), by 

changing the ‘‘yes’’ in column 2 to a 

‘‘no.’’ Section 63.10(d)(5)(ii) describes 

an immediate report for startups, 

shutdown and malfunctions when a 

source failed to meet an applicable 

standard, but did not follow the SSM 

plan. We will no longer require owners 

and operators to report when actions 

taken during a startup, shutdown or 

malfunction were not consistent with an 

SSM plan, because plans would no 

longer be required to allow the EPA to 

determine the severity of the failure to 

meet an applicable standard and to 

provide data that may document how 

the source met the general duty to 

minimize emissions during a failure to 

meet an applicable standard. 

4. Technical Amendments to the 

Aerospace NESHAP 

The EPA is also proposing the 

following technical corrections: 

• Revising 40 CFR 63.743(a)(2) to 

match the section title in 40 CFR 63.5. 

• Revising 40 CFR 63.743(a)(8) to 

correct the reference to paragraph 

63.6(i)(12)(iii)(B) by changing the ‘‘(1)’’ 

to an ‘‘(i).’’ 

• Revising 40 CFR 63.744(a) to correct 

and clarify the format of the reference to 

40 CFR 63.744(a)(1) through (4). 

• Correct the ordering of 40 CFR 

63.744(a)(3) and (4); currently paragraph 

(a)(4) is printed before (a)(3). 

• Correcting the paragraph numbering 

for 40 CFR 63.746(b)(4)(ii)(C) by 

changing paragraph (C) from a lower 

case to upper case ‘‘C.’’ 

• Correcting the numbering of the 

tables in 40 CFR 63.745 to account for 

the proposed addition of Table 1 to that 

section to include specialty coating 

limits. 

• Revising 40 CFR 63.749(d)(4) to 

correct the references to 40 CFR 

63.749(d)(4)(i) through (d)(4)(iv) and (e). 

• Revising 40 CFR 63.750(g)(6)(i) to 

remove the letters ‘‘VR/FD’’ that were 

inadvertently included. 

5. Amendments To Simplify 

Recordkeeping and Reporting for 

Compliant Coatings 

The EPA is proposing to revise 40 

CFR 63.750 to include alternative 

compliance demonstration provisions 

for all coatings subject to the Aerospace 

NESHAP (primers, topcoats, specialty 

coatings and chemical milling 

maskants). If the manufacturer’s 

supplied formulation data or calculation 

of HAP and VOC content indicate that 

the coating meets the organic HAP and 

VOC content emission limits for its 

coating type, as specified in 40 CFR 

63.745(c) and 63.747(c), then the owner 

or operator would not be required to 

demonstrate compliance for these 

coatings using the test method and 

calculations specified in 40 CFR 

63.750(c), (e), (k) and (m) or to keep the 

associated records and submit the 

associated reports associated with these 

methods and calculations. Instead, the 

owner or operator would be able to rely 

on the manufacturers’ formulation data 

and calculation of the HAP or VOC 

content to demonstrate compliance. 

However, the owner or operator would 

still be required to maintain purchase 

records and manufacturer’s supplied 

data sheets for these compliant coatings. 

Owners or operators of facilities using 

these coatings would also still be 

required to handle and transfer these 

coatings in a manner that minimizes 

spills, apply these coatings using one or 

more of the specified application 

techniques and comply with inorganic 

HAP emission requirements. 

This change is being proposed to 

reduce unnecessary recordkeeping and 

avoid the need for owners or operators 

to perform tests to measure VOC and 

HAP content and to perform certain 

calculations that can be done by the 

coating manufacturer based on coating 

formulation data. When the Aerospace 

NESHAP was originally promulgated, 

the original compliance demonstration 

and recordkeeping requirements were 

needed because the product data sheets 

provided by coating manufacturers did 

not routinely provide VOC content in 

grams per liter (less water and exempt 

solvents) or HAP content in grams per 

liter (less water). As a result, it was 

necessary for the facilities to calculate 

the VOC or HAP content in this format 

to demonstrate compliance. 

Since promulgation of the Aerospace 

NESHAP, coating manufacturers now 

commonly provide VOC content of the 

coatings, in grams per liter (less water 

and exempt solvents) on the product 

data sheets, based on coating 

formulation. Therefore, the coating 

manufacturer’s documentation can be 

used to demonstrate compliance, when 

available, in place of the compliance 

demonstrations based on VOC 

measurements and compliance 

calculations. 

We are proposing that this alternative 

apply to all coatings subject to the 

Aerospace NESHAP, including specialty 

coatings, topcoats, primers and 

chemical milling maskants. Due to the 

existence of the Aerospace NESHAP for 

nearly 20 years and the prevalence of 

state and regional VOC regulations for 

many types of coatings, coating 

manufacturers have come to recognize 

the value of providing documentation of 

HAP and VOC content to their 

customers to facilitate compliance 

demonstrations with state and federal 

regulations. For all coatings subject to 

the Aerospace NESHAP, the EPA has 

determined that onsite purchase records 

and the manufacturer’s supplied data 

sheets for the coatings will provide 

sufficient information to establish 

compliance with the content limit 

standards in the Aerospace NESHAP. 

If a facility elects to comply with the 

averaging provisions in 40 CFR 

63.743(d), the facility is also required to 

comply with all related averaging 

provisions in the Aerospace NESHAP 

for all coatings included in averaging 

(e.g., compliance determination 

provisions in 40 CFR 63.749(d) and (h); 

procedures and methods in 40 CFR 

63.750(d), (f), (l) and (n); recordkeeping 


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provisions in 40 CFR 63.752(c) and (f); 

and reporting provisions in 63.753(c) 

and (e)). Note that, in complying with 

the current averaging provisions, 

facilities may already use 

manufacturers’ data for coatings to 

determine the organic HAP and VOC 

weight fraction of coatings to perform 

the calculations in 40 CFR 63.750(d), (f), 

(l) and (n). 

F. What compliance dates are we 

proposing? 

The EPA is proposing that all of the 

amendments being proposed in this 

action would be effective on the date 60 

days after these proposed amendments 

are final, with one exception. The one 

exception is that existing specialty 

coating affected sources (i.e., existing on 

the date these changes are final) would 

have 1 year after the date this rule is 

final to comply with the standards for 

specialty coatings proposed in 40 CFR 

63.745(c)(5) and (6) (HAP and VOC 

limits for specified coatings) and the 

provisions in 40 CFR 63.745(f) (coating 

application equipment) and 40 CFR 

63.745(g) (control of inorganic HAP 

emissions). The EPA is proposing this 

compliance schedule so that existing 

sources would have time to develop the 

recordkeeping and reporting systems 

needed to comply with the requirements 

for specialty coatings. Facilities may 

also need this time to identify 

alternative coatings for those that are 

not currently compliant with the HAP 

or VOC content limits and to take any 

steps needed to upgrade specialty 

coating operations to comply with the 

application equipment requirements in 

40 CFR 63.745(f) and the inorganic HAP 

emissions requirements in 40 CFR 

63.745(g). 

The tasks necessary for existing 

facilities to comply with the other 

proposed amendments require no time 

or resources. Therefore, EPA believes 

that existing facilities will be able to 

comply with the other proposed 

amendments, including those related to 

SSM periods, as soon as the final rule 

is effective, which will be the date 60 

days after publication of the final rule. 

Therefore, the EPA is specifically 

soliciting comment and additional data 

on the burden of complying with the 

other proposed amendments. 

V. Summary of Cost, Environmental 

and Economic Impacts 

A. What are the affected sources? 

The EPA estimates, based on the 

responses to the 2011 ICR, that there are 

144 major source facilities that are 

engaged in aerospace manufacturing 

and rework surface coating operations. 

The EPA estimates that 109 facilities 

likely would be affected by the 

proposed limits for specialty coatings 

and the requirements to use highefficiency application equipment for 

specialty coatings, also based on the 

responses to the 2011 ICR. 

B. What are the air quality impacts? 

The EPA estimates that annual HAP 

emissions from specialty coatings are 

about 360 tpy; inorganic HAP emissions 

are about 5 tpy and the remainder are 

organic HAP. The estimated emission 

reductions are 58 tons of HAP, which 

would be achieved from the proposed 

regulation of specialty coatings. The 

EPA estimated that these emission 

reductions would result from the 

proposed requirements to use highefficiency application equipment and 

also from the application of the HAP 

content limits to specialty coatings. 

C. What are the cost impacts? 

The EPA estimates that the annual 

cost impacts would be about $590,000 

per year. The cost impacts would be 

attributed to monitoring and 

recordkeeping costs for complying with 

the specialty coating HAP content 

limits. The cost per facility was 

estimated based on the number of 

specialty coatings used at each facility, 

as reported in the 2011 ICR. The costs 

are based on an assumption of 1 hour 

of technical labor for annual 

recordkeeping and reporting for each 

specialty coating used by a facility, plus 

additional management and clerical 

hours representing a fraction of the 

technical labor hours. 

The EPA does not have sufficient data 

from the 2011 ICR to estimate the total 

cost impacts for specialty coatings 

having to comply with the proposed 

high-efficiency application equipment 

requirement. Because high-efficiency 

application equipment generates less 

coating overspray than conventional 

equipment, the costs of upgrading to 

new equipment can be offset by cost 

savings from reduced coating 

consumption and reduced spray booth 

filter maintenance. For these reasons, 

many facilities are likely to have already 

switched to high-efficiency application 

methods for specialty coating 

operations, as they are already required 

to for primer and topcoat application 

operations. For example, the average 

volume of specialty coatings used per 

facility is 3,000 gallons per year, based 

on the 2011 ICR data. The estimated 

purchase cost for a professional quality 

HVLP spray gun is $700 for the gun and 

hoses. If the average facility had to 

purchase three new spray guns, and the 

facility was spending an average of $30 

per gallon of spray applied coating, the 

facility would need to see a decrease in 

coating consumption of only 70 gallons 

per year (about a 3-percent reduction) to 

recover the initial cost of those three 

spray guns in 1 year. 

The EPA expects some additional 

potential cost savings from the proposal 

to include an alternative compliance 

demonstration provision in 40 CFR 

63.750(c), (e), (k) and (m). However, we 

do not have sufficient data to estimate 

the cost savings associated with the 

proposed alternative compliance 

demonstration. However, the estimated 

cost to perform an analysis of VOC 

content according to EPA Method 24, 

based on published vendor data, is 

about $575 per sample. Because the 

proposed alternative compliance 

demonstration would allow facilities to 

use coating manufacturers’ 

documentation of VOC content based on 

coating composition, the cost of these 

coating analyses using EPA Method 24 

would be avoided. 

The EPA’s cost analyses are 

documented in the memorandum, 

Methodology for Estimating Control 

Costs for Specialty Coating Operations 

in the Aerospace Source Category, 

January 2014, in the docket for this 

rulemaking. 

EPA is specifically soliciting 

comment and additional data on the 

cost impacts associated with using 

coatings that are compliant with the 

proposed limits for specialty coatings. 

D. What are the economic impacts? 

Economic impact analyses focus on 

changes in market prices and output 

levels. If changes in market prices and 

output levels in the primary markets are 

significant enough, impacts on other 

markets are also examined. Both the 

magnitude of costs needed to comply 

with the rule and the distribution of 

these costs among affected facilities can 

have a role in determining how the 

market will change in response to a rule. 

This rule applies to the surface 

coating and related operations at 

facilities that are major sources and are 

engaged, either in part or in whole, in 

the manufacture or rework of 

commercial, civil or military aerospace 

vehicles or components. The proposed 

rule would add recordkeeping and 

reporting provisions for specialty 

coating operations, but would not 

change the compliance costs for 

operations already being regulated by 

the existing emission standards. 

Therefore, the annual costs were 

calculated for only the 109 Aerospace 

Manufacturing and Rework Facilities 

that reported having specialty coating 

operations. 


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The estimated annual costs for this 

proposed rule are less than $1 million 

in the first year and in succeeding years 

(less than $850,000 in the first year and 

less than $600,000 in succeeding years). 

These costs are estimated for the 109 

facilities that, based on information 

reported by facilities, appear to have 

specialty coating operations. Thus, the 

average cost per facility is less than 

$10,000 per year. These costs are small 

compared to sales for the companies in 

aerospace manufacturing and 

reworking. For example, in 2012 the 

average annual value of shipments (a 

rough estimate of sales) for firms in the 

category of ‘‘other aircraft parts and 

auxiliary equipment manufacturing’’ 

was almost $50 million (Source: U.S. 

Census Bureau, 2012 Economic Census 

for NAICS 336413 for 2012). In this case 

the cost-to-sales estimate would be 

approximately 0.02 percent of sales for 

each firm. Costs this small would not 

have significant market impacts, 

whether they were absorbed by the firm 

or passed on as price increases. 

The EPA does not know of any firms 

that are small entities and using 

specialty coatings that are potentially 

subject to this proposed rule. Because 

no small firms face control costs, there 

is no significant impact on small 

entities. Therefore, we do not expect 

these proposed amendments to have a 

significant impact on a substantial 

number of small entities. 

E. What are the benefits? 

We anticipate this rulemaking to 

reduce organic and inorganic HAP 

emissions by approximately 58 tons 

each year. These avoided emissions will 

result in improvements in air quality 

and reduced negative health effects 

associated with exposure to air 

pollution of these emissions. However, 

we have not quantified or monetized the 

benefits of reducing these emissions for 

this rulemaking because the estimated 

costs for this action are less than $100 

million. 

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: http://www.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 page, 

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–2014–0830 (through one of 

the methods 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: http://www.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 OMB for review. 

B. Paperwork Reduction Act (PRA) 

The information collection activities 

in this proposed rule have been 

submitted for approval to the OMB 

under the PRA. The ICR document that 

the EPA prepared has been assigned 

EPA ICR number 1687.10. You can find 

a copy of the ICR in the docket for this 

rule, and it is briefly summarized here. 

Respondents are owners or operators 

of aerospace manufacturing and rework 

operations. The proposed rule would 

add recordkeeping and reporting 

provisions for specialty coating 

operations, but would not change the 

recordkeeping and reporting provisions 

for any other types of operations. 

Therefore, of the 144 Aerospace 

Manufacturing and Rework Facilities 

subject to the Aerospace NESHAP, the 

annual costs for increased 

recordkeeping and reporting would 

apply to only the 109 Aerospace 

Manufacturing and Rework Facilities 

that reported having specialty coating 

operations. Respondents must keep 

records of the specialty coatings used at 

the facility, including the name and 

VOC content of the coating, the HAP 

and VOC emitted per gallon of coating 

and the monthly volume of each coating 

used. Respondents must also submit 

semiannual reports of noncompliance. 

Recordkeeping and reporting of 

monitored parameters related to air 

pollution control technologies is 

required if controls are used to 

demonstrate compliance with the 

standards. The reports and records will 

be used to determine compliance with 

the standards. 

Respondents/affected entities: 

Aerospace manufacturing and rework 

facilities using specialty coatings. 

Respondent’s obligation to respond: 

Mandatory (40 CFR part 63, subpart 

GG). 

Estimated number of respondents: 

109 facilities using specialty coatings. 

Frequency of response: Initially, 

occasionally and semiannually. 

Total estimated burden: 6,914 hours 

(per year) for the responding facilities 

and 148 hours (per year) for the agency. 

These are estimates for the average 

annual burden for the first 3 years after 

the rule is final. Burden is defined at 5 

CFR 1320.3(b). 

Total estimated cost: $695,570 (per 

year), which includes no annualized 


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capital or operation and maintenance 

costs, for the responding facilities and 

$8,740 (per year) for the agency. These 

are estimates for the average annual cost 

for the first 3 years after the rule is final. 

An agency may not conduct or 

sponsor, and a person is not required to 

respond to, a collection of information 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for the EPA’s regulations in 40 

CFR are listed in 40 CFR part 9. To 

comment on the agency’s need for this 

information, the accuracy of the 

provided burden estimates and any 

suggested methods for minimizing 

respondent burden, the EPA has 

established a public docket for this rule, 

which includes this ICR, under Docket 

ID No. EPA–HQ–OAR–2014–0830. 

Submit your comments on the 

Agency’s need for this information, the 

accuracy of the provided burden 

estimates and any suggested methods 

for minimizing respondent burden to 

the EPA using the docket identified at 

the beginning of this rule. You may also 

send your ICR-related comments to 

OMB’s Office of Information and 

Regulatory Affairs via email to oria_

submissions@omb.eop.gov, Attention: 

Desk Officer for the EPA. Since OMB is 

required to make a decision concerning 

the ICR between 30 and 60 days after 

receipt, OMB must receive comments no 

later than March 19, 2015. The EPA will 

respond to any ICR-related comments in 

the final rule. 

C. 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. This action will not 

impose any requirements on small 

entities. No facilities meeting the Small 

Business Administration’s definition of 

a small business would face significant 

control costs, based on the economic 

impact analysis completed for this 

action. The results of this analysis are 

summarized in section V.D of this 

preamble and can be found in the 

memorandum, Economic Impact 

Analysis for Proposed National 

Emission Standards for Aerospace 

Manufacturing and Rework Facilities, 

December 3, 2014. A copy of this 

memorandum is in the docket for this 

rulemaking. 

D. Unfunded Mandates Reform Act 

(UMRA) 

This action does not contain an 

unfunded mandate of $100 million or 

more as described in the 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. 

E. 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. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does not have tribal 

implications as specified in Executive 

Order 13175. No tribal facilities are 

known to be engaged in the aerospace 

manufacturing or rework surface coating 

operations that would be affected by 

this action. Thus, Executive Order 

13175 does not apply to this action. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

This action is not subject to Executive 

Order 13045 because it is not 

economically significant as defined in 

Executive Order 12866, and because the 

EPA does not believe the environmental 

health or safety risks addressed by this 

action present a disproportionate risk to 

children. This action’s health and risk 

assessments are contained in sections 

III.A and B and sections IV.B and C of 

this preamble. 

H. 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. 

I. National Technology Transfer and 

Advancement Act (NTTAA) 

This rulemaking does not involve 

technical standards. 

J. Executive Order 12898: Federal 

Actions to Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

The EPA believes the human health or 

environmental risk addressed by this 

action will not have potential 

disproportionately high and adverse 

human health or environmental effects 

on minority, low-income or indigenous 

populations. 

These proposed standards will 

improve public health and welfare, now 

and in the future, by reducing HAP 

emissions contributing to environmental 

and human health impacts. These 

reductions in HAP associated with the 

rule are expected to benefit all 

populations. 

To examine the potential for any 

environmental justice issues that might 

be associated with the Aerospace 

Manufacturing and Rework source 

category, we evaluated the distributions 

of HAP related cancer and non-cancer 

risks across different social, 

demographic and economic groups 

within the populations living near the 

facilities where this source category is 

located. The methods used to conduct 

demographic analyses for this proposed 

rule are described in the document, Risk 

and Technology Review—Analysis of 

Socio-Economic Factors for Populations 

Living Near Aerospace Facilities, which 

may be found in the docket for this 

rulemaking (Docket ID No. EPA–HQ– 

OAR–2014–0830). 

In the demographics analysis, we 

focused on populations within 50 km of 

the facilities in this source category with 

emissions sources subject to the MACT 

standard. More specifically, for these 

populations, we evaluated exposures to 

HAP that could result in cancer risks of 

1-in-1 million or greater. We compared 

the percentages of particular 

demographic groups within the focused 

populations to the total percentages of 

those demographic groups nationwide. 

The results of this analysis are 

documented in the document, Risk and 

Technology Review—Analysis of SocioEconomic Factors for Populations Living 

Near Aerospace Facilities. 

List of Subjects in 40 CFR Part 63 

Environmental protection, Air 

pollution control, Hazardous 

substances, Reporting and 

recordkeeping requirements. 

Dated: January 22, 2015. 

Gina McCarthy, 

Administrator. 

For the reasons stated in the 

preamble, part 63 of title 40, chapter I, 

of the Code of Federal Regulations is 

proposed to be amended 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 GG—National Emission 

Standards for Aerospace 

Manufacturing and Rework Facilities 

■ 2. Section 63.741 is amended by: 


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■ a. Revising paragraph (c) introductory 

text; 

■ b. Redesignating paragraphs (c)(4) 

through (c)(7) as paragraphs (c)(5) 

through (c)(8); 

■ c. Adding new paragraph (c)(4); 

■ d. Revising newly redesignated 

paragraph (c)(8); and 

■ e. Revising paragraphs (f) and (g). 

The revisions and addition read as 

follows: 

§ 63.741 Applicability and designation of 

affected sources. 

* * * * * 

(c) Affected sources. The affected 

sources to which the provisions of this 

subpart apply are specified in 

paragraphs (c)(1) through (8) of this 

section. The activities subject to this 

subpart are limited to the manufacture 

or rework of aerospace vehicles or 

components as defined in this subpart. 

Where a dispute arises relating to the 

applicability of this subpart to a specific 

activity, the owner or operator shall 

demonstrate whether or not the activity 

is regulated under this subpart. 

* * * * * 

(4) For organic HAP or VOC 

emissions, each specialty coating 

application operation, which is the total 

of all specialty coating applications at 

the facility. 

* * * * * 

(8) For inorganic HAP emissions, each 

spray booth or hangar that contains a 

primer, topcoat or specialty coating 

application operation subject to 

§ 63.745(g), or a depainting operation 

subject to § 63.746(b)(4). 

* * * * * 

(f) This subpart does not regulate 

research and development, quality 

control and laboratory testing activities, 

chemical milling, metal finishing, 

electrodeposition (except for 

electrodeposition of paints), composites 

processing (except for cleaning and 

coating of composite parts or 

components that become part of an 

aerospace vehicle or component as well 

as composite tooling that comes in 

contact with such composite parts or 

components prior to cure), electronic 

parts and assemblies (except for 

cleaning and topcoating of completed 

assemblies), manufacture of aircraft 

transparencies and wastewater 

operations at aerospace facilities. These 

requirements do not apply to the rework 

of aircraft or aircraft components if the 

holder of the Federal Aviation 

Administration (FAA) design approval, 

or the holder’s licensee, is not actively 

manufacturing the aircraft or aircraft 

components. These requirements also 

do not apply to parts and assemblies not 

critical to the vehicle’s structural 

integrity or flight performance. The 

requirements of this subpart also do not 

apply to primers, topcoats, specialty 

coatings, chemical milling maskants, 

strippers and cleaning solvents 

containing HAP and VOC at 

concentrations less than 0.1 percent by 

mass for carcinogens or 1.0 percent by 

mass for noncarcinogens, as determined 

from manufacturer’s representations, 

such as in a material safety data sheet 

or product data sheet or testing. 

Additional specific exemptions from 

regulatory coverage are set forth in 

paragraphs (e), (g), (h), (i) and (j) of this 

section and §§ 63.742, 63.744(a)(1), (b), 

(e), 63.745(a), (f)(3), (g)(4), 63.746(a), 

(b)(5), 63.747(c)(3) and 63.749(d). 

(g) The requirements for primers, 

topcoats, specialty coatings and 

chemical milling maskants in §§ 63.745 

and 63.747 do not apply to the use of 

low-volume coatings in these categories 

for which the annual total of each 

separate formulation used at a facility 

does not exceed 189 liters (50 gal), and 

the combined annual total of all such 

primers, topcoats, specialty coatings and 

chemical milling maskants used at a 

facility does not exceed 757 liters (200 

gal). Primers, topcoats and specialty 

coatings exempted under paragraph (f) 

of this section and under § 63.745(f)(3) 

and (g)(4) are not included in the 50 and 

200 gal limits. Chemical milling 

maskants exempted under § 63.747(c)(3) 

are also not included in these limits. 

* * * * * 

■ 3. Section 63.742 is amended by 

revising the definitions for ‘‘Chemical 

milling maskant’’; ‘‘Softener’’; and 

‘‘Stripper’’ to read as follows: 

§ 63.742 Definitions. 

* * * * * 

Chemical milling maskant means a 

coating that is applied directly to 

aluminum components to protect 

surface areas when chemical milling the 

component with a Type I or Type II 

etchant. Type I chemical milling 

maskants are used with a Type I etchant 

and Type II chemical milling maskants 

are used with a Type II etchant. This 

definition does not include bonding 

maskants, critical use and line sealer 

maskants and seal coat maskants. 

Additionally, maskants that must be 

used with a combination of Type I or II 

etchants and any of the above types of 

maskants (i.e., bonding, critical use and 

line sealer and seal coat) are also not 

included in this definition. (See also 

Type I and Type II etchant definitions.) 

* * * * * 

Softener means a liquid that is 

applied to an aerospace vehicle or 

component to degrade coatings such as 

primers, topcoats and specialty coatings 

specifically as a preparatory step to 

subsequent depainting by non-chemical 

based depainting equipment. Softeners 

may contain VOC, but shall not contain 

any HAP as determined from MSDS’s or 

manufacturer supplied information. 

* * * * * 

Stripper means a liquid that is applied 

to an aerospace vehicle or component to 

remove permanent coatings such as 

primers, topcoats and specialty coatings. 

* * * * * 

■ 4. Section 63.743 is amended by: 

■ a. Revising paragraphs (a)(2), (8), and 

(10); 

■ b. Removing and reserving paragraph 

(b); 

■ c. Revising paragraphs (d)(1), (2), and 

(3); 

■ d. Removing and reserving paragraphs 

(d)(4) and (5); 

■ e. Adding paragraph (e). 

The revisions and addition read as 

follows: 

§ 63.743 Standards: General. 

(a) * * * 

(2) § 63.5, Preconstruction review and 

notification requirements; and 

* * * * * 

(8) For the purposes of this subpart, 

each owner or operator is to be provided 

30 calendar days to present additional 

information to the Administrator after 

he/she is notified of the intended denial 

of a compliance extension request 

submitted under either § 63.6(i)(4) or 

(5), rather than 15 calendar days as 

provided for in § 63.6(i)(12)(iii)(B) and 

§ 63.6(i)(13)(iii)(B). 

* * * * * 

(10) For the purposes of compliance 

with the requirements of § 63.5(b)(4) of 

the General Provisions and this subpart, 

owners or operators of existing primer, 

topcoat or specialty coating application 

operations and depainting operations 

who construct or reconstruct a spray 

booth or hangar that does not have the 

potential to emit 10 tons/yr or more of 

an individual inorganic HAP or 25 tons/ 

yr or more of all inorganic HAP 

combined shall only be required to 

notify the Administrator of such 

construction or reconstruction on an 

annual basis. Notification shall be 

submitted on or before March 1 of each 

year and shall include the information 

required in § 63.5(b)(4) for each such 

spray booth or hangar constructed or 

reconstructed during the prior calendar 

year, except that such information shall 

be limited to inorganic HAP’s. No 

advance notification or written approval 

from the Administrator pursuant to 

§ 63.5(b)(3) shall be required for the 


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construction or reconstruction of such a 

spray booth or hangar unless the booth 

or hangar has the potential to emit 10 

tons/yr or more of an individual 

inorganic HAP or 25 tons/yr or more of 

all inorganic HAP combined. 

* * * * * 

(d) * * * 

(1) Each owner or operator of a new 

or existing source shall use any 

combination of primers, topcoats 

(including self-priming topcoats), 

specialty coatings, Type I chemical 

milling maskants or Type II chemical 

milling maskants such that the monthly 

volume-weighted average organic HAP 

and VOC contents of the combination of 

primers, topcoats, specialty coatings, 

Type I chemical milling maskants or 

Type II chemical milling maskants, as 

determined in accordance with the 

applicable procedures set forth in 

§ 63.750, complies with the specified 

content limits in §§ 63.745(c) and 

63.747(c), unless the permitting agency 

specifies a shorter averaging period as 

part of an ambient ozone control 

program. 

(2) Averaging is allowed only for 

uncontrolled primers, topcoats 

(including self-priming topcoats), 

specialty coatings, Type I chemical 

milling maskants or Type II chemical 

milling maskants. 

(3) Averaging is not allowed between 

specialty coating types defined in 

Appendix A to this subpart, or between 

the different types of coatings specified 

in paragraphs (d)(3)(i) through (vii) of 

this section. 

(i) Primers and topcoats (including 

self-priming topcoats). 

(ii) Type I and Type II chemical 

milling maskants. 

(iii) Primers and chemical milling 

maskants. 

(iv) Topcoats and chemical milling 

maskants. 

(v) Primers and specialty coatings. 

(vi) Topcoats and specialty coatings. 

(vii) Chemical milling maskants and 

specialty coatings. 

* * * * * 

(e) At all times, the owner or operator 

must operate and maintain any affected 

source, including associated air 

pollution control equipment and 

monitoring equipment, in a manner 

consistent with safety and good air 

pollution control practices for 

minimizing emissions. The general duty 

to minimize emissions does not require 

the owner or operator to make any 

further efforts to reduce emissions if 

levels required by the applicable 

standard have been achieved. 

Determination of whether a source is 

operating in compliance with operation 

and maintenance requirements will be 

based on information available to the 

Administrator which may include, but 

is not limited to, monitoring results, 

review of operation and maintenance 

procedures, review of operation and 

maintenance records and inspection of 

the source. 

■ 5. Section 63.744 is amended by: 

■ a. Revising paragraph (a) introductory 

text; and 

■ b. Correcting the numerical order of 

paragraphs (a)(3) and (4). 

The revision reads as follows: 

§ 63.744 Standards: Cleaning operations. 

(a) Housekeeping measures. Each 

owner or operator of a new or existing 

cleaning operation subject to this 

subpart shall comply with the 

requirements in paragraphs (a)(1) 

through (4) of this section unless the 

cleaning solvent used is identified in 

Table 1 of this section or contains HAP 

and VOC below the de minimis levels 

specified in § 63.741(f). 

* * * * * 

■ 6. Section 63.745 is amended by: 

■ a. Revising the section heading; 

■ b. Revising paragraphs (a), (b), and (c) 

introductory text; 

■ c. Adding paragraphs (c)(5), (c)(6) and 

Table 1; 

■ d. Revising paragraphs (e) 

introductory text and (e)(1); 

■ e. Revising paragraphs (f) introductory 

text, (f)(1) introductory text and (f)(2); 

■ f. Revising paragraphs (g) introductory 

text, (g)(2)(i), (g)(2)(ii), and (g)(2)(iii)(B). 

The revisions and additions read as 

follows: 

§ 63.745 Standards: Primer, topcoat and 

specialty coating application operations. 

(a) Each owner or operator of a new 

or existing primer, topcoat or specialty 

coating application operation subject to 

this subpart shall comply with the 

requirements specified in paragraph (c) 

of this section for those coatings that are 

uncontrolled (no control device is used 

to reduce organic HAP emissions from 

the operation), and in paragraph (d) of 

this section for those coatings that are 

controlled (organic HAP emissions from 

the operation are reduced by the use of 

a control device). Aerospace equipment 

that is no longer operational, intended 

for public display and not easily capable 

of being moved is exempt from the 

requirements of this section. 

(b) Each owner or operator shall 

conduct the handling and transfer of 

primers, topcoats and specialty coatings 

to or from containers, tanks, vats, 

vessels and piping systems in such a 

manner that minimizes spills. 

(c) Uncontrolled coatings—organic 

HAP and VOC content levels. Each 

owner or operator shall comply with the 

organic HAP and VOC content limits 

specified in paragraphs (c)(1) through 

(6) of this section for those coatings that 

are uncontrolled. 

* * * * * 

(5) Organic HAP emissions from 

specialty coatings shall be limited to an 

organic HAP content level of no more 

than the HAP content limit specified in 

Table 1 of this section for each 

applicable specialty coating type. 

(6) VOC emissions from specialty 

coatings shall be limited to a VOC 

content level of no more than the VOC 

content limit specified in Table 1 of this 

section for each applicable specialty 

coating type. 

TABLE 1—SPECIALTY COATINGS—HAP AND VOC CONTENT LIMITS

Coating type HAP limit g/L 

(lb/gallon) 1

VOC Limit g/L 

(lb/gallon) 1

Ablative Coating ....................................................................................................................................................... 600 (5.0) 600 (5.0) 

Adhesion Promoter .................................................................................................................................................. 890 (7.4) 890 (7.4) 

Adhesive Bonding Primers: Cured at 250 °F or below ........................................................................................... 850 (7.1) 850 (7.1) 

Adhesive Bonding Primers: Cured above 250 °F ................................................................................................... 1,030 (8.6) 1,030 (8.6) 

Commercial Interior Adhesive ................................................................................................................................. 760 (6.3) 760 (6.3) 

Cyanoacrylate Adhesive .......................................................................................................................................... 1,020 (8.5) 1,020 (8.5) 

Fuel Tank Adhesive ................................................................................................................................................. 620 (5.2) 620 (5.2) 

Nonstructural Adhesive ............................................................................................................................................ 360 (3.0) 360 (3.0) 

Rocket Motor Bonding Adhesive ............................................................................................................................. 890 (7.4) 890 (7.4) 

Rubber-based Adhesive .......................................................................................................................................... 850 (7.1) 850 (7.1) 

Structural Autoclavable Adhesive ............................................................................................................................ 60 (0.5) 60 (0.5) 

Structural Nonautoclavable Adhesive ...................................................................................................................... 850 (7.1) 850 (7.1) 


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TABLE 1—SPECIALTY COATINGS—HAP AND VOC CONTENT LIMITS—Continued 

Coating type HAP limit g/L 

(lb/gallon) 1

VOC Limit g/L 

(lb/gallon) 1

Antichafe Coating .................................................................................................................................................... 660 (5.5) 660 (5.5) 

Bearing Coating ....................................................................................................................................................... 620 (5.2) 620 (5.2) 

Caulking and Smoothing Compounds ..................................................................................................................... 850 (7.1) 850 (7.1) 

Chemical Agent-Resistant Coating .......................................................................................................................... 550 (4.6) 550 (4.6) 

Clear Coating ........................................................................................................................................................... 720 (6.0) 720 (6.0) 

Commercial Exterior Aerodynamic Structure Primer .............................................................................................. 650 (5.4) 650 (5.4) 

Compatible Substrate Primer .................................................................................................................................. 780 (6.5) 780 (6.5) 

Corrosion Prevention Compound ............................................................................................................................ 710 (5.9) 710 (5.9) 

Cryogenic Flexible Primer ....................................................................................................................................... 645 (5.4) 645 (5.4) 

Cryoprotective Coating ............................................................................................................................................ 600 (5.0) 600 (5.0) 

Dry Lubricative Material ........................................................................................................................................... 880 (7.3) 880 (7.3) 

Electric or Radiation-Effect Coating ........................................................................................................................ 800 (6.7) 800 (6.7) 

Electrostatic Discharge and Electromagnetic Interference (EMI) Coating .............................................................. 800 (6.7) 800 (6.7) 

Elevated-Temperature Skydrol-Resistant Commercial Primer ................................................................................ 740 (6.2) 740 (6.2) 

Epoxy Polyamide Topcoat ....................................................................................................................................... 660 (5.5) 660 (5.5) 

Fire-Resistant (interior) Coating .............................................................................................................................. 800 (6.7) 800 (6.7) 

Flexible Primer ......................................................................................................................................................... 640 (5.3) 640 (5.3) 

Flight-Test Coatings: Missile or Single Use Aircraft ................................................................................................ 420 (3.5) 420 (3.5) 

Flight-Test Coatings: All Other ................................................................................................................................ 840 (7.0) 840 (7.0) 

Fuel-Tank Coating ................................................................................................................................................... 720 (6.0) 720 (6.0) 

High-Temperature Coating ...................................................................................................................................... 850 (7.1) 850 (7.1) 

Insulation Covering .................................................................................................................................................. 740 (6.2) 740 (6.2) 

Intermediate Release Coating ................................................................................................................................. 750 (6.3) 750 (6.3) 

Lacquer .................................................................................................................................................................... 830 (6.9) 830 (6.9) 

Bonding Maskant ..................................................................................................................................................... 1,230 (10.3) 1,230 (10.3) 

Critical Use and Line Sealer Maskant ..................................................................................................................... 1,020 (8.5) 1,020 (8.5) 

Seal Coat Maskant .................................................................................................................................................. 1,230 (10.3) 1,230 (10.3) 

Metalized Epoxy Coating ......................................................................................................................................... 740 (6.2) 740 (6.2) 

Mold Release ........................................................................................................................................................... 780 (6.5) 780 (6.5) 

Optical Anti-Reflective Coating ................................................................................................................................ 750 (6.3) 750 (6.3) 

Part Marking Coating ............................................................................................................................................... 850 (7.1) 850 (7.1) 

Pretreatment Coating ............................................................................................................................................... 780 (6.5) 780 (6.5) 

Rain Erosion-Resistant Coating .............................................................................................................................. 850 (7.1) 850 (7.1) 

Rocket Motor Nozzle Coating .................................................................................................................................. 660 (5.5) 660 (5.5) 

Scale Inhibitor .......................................................................................................................................................... 880 (7.3) 880 (7.3) 

Screen Print Ink ....................................................................................................................................................... 840 (7.0) 840 (7.0) 

Extrudable/Rollable/Brushable Sealant ................................................................................................................... 280 (2.3) 280 (2.3) 

Sprayable Sealant ................................................................................................................................................... 600 (5.0) 600 (5.0) 

Silicone Insulation Material ...................................................................................................................................... 850 (7.1) 850 (7.1) 

Solid Film Lubricant ................................................................................................................................................. 880 (7.3) 880 (7.3) 

Specialized Function Coating .................................................................................................................................. 890 (7.4) 890 (7.4) 

Temporary Protective Coating ................................................................................................................................. 320 (2.7) 320 (2.7) 

Thermal Control Coating ......................................................................................................................................... 800 (6.7) 800 (6.7) 

Wet Fastener Installation Coating ........................................................................................................................... 675 (5.6) 675 (5.6) 

Wing Coating ........................................................................................................................................................... 850 (7.1) 850 (7.1) 

1 Coating limits for HAP are expressed in terms of mass (grams or pounds) of HAP per volume (liters or gallons) of coating less water. Coating 

limits for VOC are expressed in terms of mass (grams or pounds) of VOC per volume (liters or gallons) of coating less water and less exempt 

solvent. 

* * * * * 

(e) Compliance methods. Compliance 

with the organic HAP and VOC content 

limits specified in paragraphs (c)(1) 

through (6) of this section shall be 

accomplished by using the methods 

specified in paragraphs (e)(1) and (2) of 

this section either by themselves or in 

conjunction with one another. 

(1) Use primers, topcoats (including 

self-priming topcoats) and specialty 

coatings with HAP and VOC content 

levels equal to or less than the limits 

specified in paragraphs (c)(1) through 

(6) of this section; or 

* * * * * 

(f) Application equipment. Except as 

provided in paragraph (f)(3) of this 

section, each owner or operator of a new 

or existing primer, topcoat (including 

self-priming topcoat) or specialty 

coating application operation subject to 

this subpart in which any of the 

coatings contain organic HAP or VOC 

shall comply with the requirements 

specified in paragraphs (f)(1) and (2) of 

this section. 

(1) All primers, topcoats (including 

self-priming topcoats) and specialty 

coatings shall be applied using one or 

more of the application techniques 

specified in paragraphs (f)(1)(i) through 

(ix) of this section. 

* * * * * 

(2) All application devices used to 

apply primers, topcoats (including selfpriming topcoats) or specialty coatings 

shall be operated according to company 

procedures, local specified operating 

procedures and/or the manufacturer’s 

specifications, whichever is most 

stringent, at all times. Equipment 

modified by the facility shall maintain 

a transfer efficiency equivalent to HVLP 

and electrostatic spray application 

techniques. 

* * * * * 

(g) Inorganic HAP emissions. Except 

as provided in paragraph (g)(4) of this 

section, each owner or operator of a new 

or existing primer, topcoat or specialty 

coating application operation subject to 

this subpart in which any of the 

coatings that are spray applied contain 


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inorganic HAP, shall comply with the 

applicable requirements in paragraphs 

(g)(1) through (3) of this section. 

* * * * * 

(2) * * * 

(i) For existing sources, the owner or 

operator must choose one of the 

following: 

(A) Before exhausting it to the 

atmosphere, pass the air stream through 

a dry particulate filter system certified 

using the methods described in 

§ 63.750(o) to meet or exceed the 

efficiency data points in Tables 2 and 3 

of this section; or 

(C) Before exhausting it to the 

atmosphere, pass the air stream through 

an air pollution control system that 

meets or exceeds the efficiency data 

points in Tables 2 and 3 of this section 

and is approved by the permitting 

authority. 

TABLE 2—TWO-STAGE ARRESTOR; 

LIQUID PHASE CHALLENGE FOR EXISTING SOURCES

Filtration efficiency 

requirement, % 

Aerodynamic 

particle size 

range, μm 

>90 ........................................ >5.7 

>50 ........................................ >4.1 

>10 ........................................ >2.2 

TABLE 3—TWO-STAGE ARRESTOR; 

SOLID PHASE CHALLENGE FOR EXISTING SOURCES

Filtration efficiency 

requirement, % 

Aerodynamic 

particle size 

range, μm 

>90 ........................................ >8.1 

>50 ........................................ >5.0 

>10 ........................................ >2.6 

(ii) For new sources, either: 

(A) Before exhausting it to the 

atmosphere, pass the air stream through 

a dry particulate filter system certified 

using the methods described in 

§ 63.750(o) to meet or exceed the 

efficiency data points in Tables 4 and 5 

of this section; or (B) Before exhausting 

it to the atmosphere, pass the air stream 

through an air pollution control system 

that meets or exceeds the efficiency data 

points in Tables 4 and 5 of this section 

and is approved by the permitting 

authority. 

TABLE 4—THREE-STAGE ARRESTOR; 

LIQUID PHASE CHALLENGE FOR NEW

SOURCES

Filtration efficiency 

requirement, % 

Aerodynamic 

particle size 

range, μm 

>95 ...................................... >2 .0 

>80 ...................................... >1 .0 

>65 ...................................... >0 .42 

TABLE 5—THREE-STAGE ARRESTOR; 

SOLID PHASE CHALLENGE FOR NEW

SOURCES

Filtration efficiency 

requirement, % 

Aerodynamic 

particle size 

range, μm 

>95 ...................................... >2 .5 

>85 ...................................... >1 .1 

>75 ...................................... >0 .70 

(iii) * * * 

(B) If the primer, topcoat or specialty 

coating contains chromium or cadmium, 

control shall consist of a HEPA filter 

system, three-stage filter system or other 

control system equivalent to the three 

stage filter system as approved by the 

permitting agency. 

* * * * * 

■ 7. Section 63.746 is amended by 

revising (b)(4)(ii)(A) and (B) to read as 

follows: 

§ 63.746 Standards: Depainting 

operations. 

* * * * * 

(b) * * * 

(4) * * * 

(ii)(A) For existing sources, pass any 

air stream removed from the enclosed 

area or closed-cycle depainting system 

through a dry particulate filter system, 

certified using the method described in 

§ 63.750(o) to meet or exceed the 

efficiency data points in Tables 2 and 3 

of § 63.745, through a baghouse or 

through a waterwash system before 

exhausting it to the atmosphere. 

(B) For new sources, pass any air 

stream removed from the enclosed area 

or closed-cycle depainting system 

through a dry particulate filter system 

certified using the method described in 

§ 63.750(o) to meet or exceed the 

efficiency data points in Tables 4 and 5 

of § 63.745 or through a baghouse before 

exhausting it to the atmosphere. 

* * * * * 

■ 8. Section 63.749 is amended by: 

■ a. Revising paragraphs (a)(1) and (2); 

■ b. Adding paragraph (a)(3); 

■ c. Revising paragraph (b); 

■ d. Revising the heading of paragraph 

(d), paragraph (d)(4) introductory text 

and paragraph (d)(4)(i); 

■ e. Revising paragraph (e) introductory 

text; 

■ f. Adding paragraph (j). 

The revisions and additions read as 

follows: 

§ 63.749 Compliance dates and 

determinations. 

(a) * * * (1) Each owner or operator 

of an existing affected source subject to 

this subpart shall comply with the 

requirements of this subpart by 

September 1, 1998, except as specified 

in paragraphs (a)(2) and (3) of this 

section. Owners or operators of new 

affected sources subject to this subpart 

shall comply on the effective date or 

upon startup, whichever is later. In 

addition, each owner or operator shall 

comply with the compliance dates 

specified in § 63.6(b) and (c) as 

indicated in Table 1 to subpart GG of 

part 63. 

(2) Owners or operators of existing 

primer, topcoat or specialty coating 

application operations and depainting 

operations who construct or reconstruct 

a spray booth or hangar must comply 

with the new source requirements for 

inorganic HAP specified in 

§§ 63.745(g)(2)(ii) and 63.746(b)(4) for 

that new spray booth or hangar upon 

startup. Such sources must still comply 

with all other existing source 

requirements by September 1, 1998. 

(3) Each owner or operator of a 

specialty coating application operation 

that begins construction or 

reconstruction after [date of publication 

of final rule in the Federal Register] 

shall be in compliance with the 

requirements of this subpart on [date of 

publication of final rule in the Federal 

Register] or upon startup, whichever is 

later. Each owner or operator of a 

specialty coating application operation 

that is existing on [date of publication 

of final rule in the Federal Register] 

shall be in compliance with the 

requirements of this subpart on or 

before [date 1 year after date of 

publication of final rule in the Federal 

Register]. 

(b) General. Each facility subject to 

this subpart shall be considered in 

noncompliance if the owner or operator 

fails to use a control device other than 

one specified in this subpart that has 

not been approved by the 

Administrator, as required by 

§ 63.743(c). 

* * * * * 

(d) Organic HAP and VOC content 

levels—primer, topcoat and specialty 

coating application operations — 

* * * * * 

(4) The topcoat or specialty coating 

application operation is considered in 

compliance when the conditions 


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8434 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

specified in paragraphs (d)(4)(i) through 

(iv) of this section, as applicable, and in 

paragraph (e) of this section are met. 

Failure to meet any of the conditions 

identified in these paragraphs shall 

constitute noncompliance. 

(i) The topcoat application operation 

is considered in compliance when the 

conditions specified in paragraphs 

(d)(4)(i)(A) are met. The specialty 

coating application operation is 

considered in compliance when the 

conditions specified in paragraphs 

(d)(4)(i)(B) are met. 

(A) For all uncontrolled topcoats, all 

values of Hi and Ha (as determined using 

the procedures specified in § 63.750(c) 

and (d)) are less than or equal to 420 

grams organic HAP per liter (3.5 lb/gal) 

of topcoat (less water) as applied, and 

all values of Gi and Ga (as determined 

using the procedures specified in 

§ 63.750(e) and (f)) are less than or equal 

to 420 grams organic VOC per liter (3.5 

lb/gal) of topcoat (less water and exempt 

solvents) as applied. 

(B) For all uncontrolled specialty 

coatings, all values of Hi and Ha (as 

determined using the procedures 

specified in § 63.750(c) and (d)) are less 

than or equal to the HAP content limits 

specified in Table 1 to § 63.745 for the 

applicable specialty coating types (less 

water) as applied, and all values of Gi

and Ga (as determined using the 

procedures specified in § 63.750(e) and 

(f)) are less than or equal to the VOC 

content limits specified in Table 1 to 

§ 63.745 for the applicable specialty 

coating types (less water and exempt 

solvents) as applied. 

* * * * * 

(e) Inorganic HAP emissions—primer, 

topcoat and specialty coating 

application operations. For each primer, 

topcoat or specialty coating application 

operation that emits inorganic HAP, the 

operation is in compliance when: 

* * * * * 

(j) Performance tests shall be 

conducted under such conditions as the 

Administrator specifies to the owner or 

operator based on representative 

performance of the affected source for 

the period being tested. Representative 

conditions exclude periods of startup 

and shutdown unless specified by the 

Administrator or an applicable subpart. 

The owner or operator may not conduct 

performance tests during periods of 

malfunction. The owner or operator 

must record the process information 

that is necessary to document operating 

conditions during the test and include 

in such record an explanation to 

support that such conditions represent 

normal operation. Upon request, the 

owner or operator shall make available 

to the Administrator such records as 

may be necessary to determine the 

conditions of performance tests. 

■ 9. Section 63.750 is amended by: 

■ a. Revising paragraphs (c) 

introductory text, (d) introductory text 

and (e) introductory text; 

■ b. Revising paragraphs (f) introductory 

text and (f)(1)(iii); 

■ c. Revising paragraph (h)(3)(i)(1); and 

■ d. Revising paragraphs (k) 

introductory text, (m) introductory text 

and (o). 

The revisions are as follows: 

§ 63.750 Test methods and procedures. 

* * * * * 

(c) Organic HAP content level 

determination—compliant primers, 

topcoats and specialty coatings. For 

those uncontrolled primers, topcoats 

and specialty coatings complying with 

the primer, topcoat or specialty coating 

organic HAP content limits specified in 

§ 63.745(c) without being averaged, the 

procedures in paragraphs (c)(1) through 

(3) of this section shall be used to 

determine the mass of organic HAP 

emitted per volume of coating (less 

water) as applied. As an alternative to 

the procedures in paragraphs (c)(1) 

through (3) of this section, an owner or 

operator may use the coating 

manufacturer’s supplied data to 

demonstrate that organic HAP emitted 

per volume of coating (less water), as 

applied, is less than or equal to the 

applicable organic HAP limit specified 

in § 63.745(c). 

* * * * * 

(d) Organic HAP content level 

determination—averaged primers, 

topcoats and specialty coatings. For 

those uncontrolled primers, topcoats 

and specialty coatings that are averaged 

together in order to comply with the 

primer, topcoat and specialty coating 

organic HAP content limits specified in 

§ 63.745(c), the following procedure 

shall be used to determine the monthly 

volume-weighted average mass of 

organic HAP emitted per volume of 

coating (less water) as applied, unless 

the permitting agency specifies a shorter 

averaging period as part of an ambient 

ozone control program. 

* * * * * 

(e) VOC content level determination— 

compliant primers, topcoats and 

specialty coatings. For those 

uncontrolled primers, topcoats and 

specialty coatings complying with the 

primer, topcoat and specialty coating 

VOC content levels specified in 

§ 63.745(c) without being averaged, the 

procedures in paragraphs (e)(1) through 

(3) of this section shall be used to 

determine the mass of VOC emitted per 

volume of coating (less water and 

exempt solvents) as applied. As an 

alternative to the procedures in 

paragraphs (e)(1) through (3) of this 

section, an owner or operator may use 

coating manufacturer’s supplied data to 

demonstrate that VOC emitted per 

volume of coating (less water and 

exempt solvents), as applied, is less 

than or equal to the applicable VOC 

limit specified in § 63.745(c). 

* * * * * 

(f) VOC content level determination— 

averaged primers, topcoats and 

specialty coatings. For those 

uncontrolled primers, topcoats and 

specialty coatings that are averaged 

within their respective coating category 

in order to comply with the primer, 

topcoat and specialty coating VOC 

content limits specified in § 63.745 

(c)(2), (4), and (6), the following 

procedure shall be used to determine 

the monthly volume-weighted average 

mass of VOC emitted per volume of 

coating (less water and exempt solvents) 

as applied, unless the permitting agency 

specifies a shorter averaging period as 

part of an ambient ozone control 

program. 

(1) * * * 

(iii) Determine the VOC content of 

each primer, topcoat and specialty 

coating formulation (less water and 

exempt solvents) as applied using EPA 

Method 24 or from manufacturer’s data. 

* * * * * 

(h) * * * 

(3) * * * 

(i)(1) Alternative application 

method—primers, topcoats and 

specialty coatings. Each owner or 

operator seeking to use an alternative 

application method (as allowed in 

§ 63.745(f)(1)(ix)) in complying with the 

standards for primers, topcoats and 

specialty coatings shall use the 

procedures specified in paragraphs 

(i)(2)(i) and (ii) or (iii) of this section to 

determine the organic HAP and VOC 

emission levels of the alternative 

application technique as compared to 

either HVLP or electrostatic spray 

application methods. 

* * * * * 

(k) Organic HAP content level 

determination—compliant chemical 

milling maskants. For those 

uncontrolled chemical milling maskants 

complying with the chemical milling 

maskant organic HAP content limit 

specified in § 63.747(c)(1) without being 

averaged, the procedure in paragraph 

(k)(1) of this section shall be used to 

determine the mass of organic HAP 

emitted per unit volume of coating 

(chemical milling maskant) i as applied 

(less water), Hi (lb/gal). As an alternative 


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to the procedures in paragraph (k)(1) of 

this section, an owner or operator may 

use coating manufacturer’s supplied 

data to demonstrate that organic HAP 

emitted per volume of coating (less 

water), as applied, is less than or equal 

to the applicable organic HAP limit 

specified in § 63.747(c). 

* * * * * 

(m) VOC content level 

determination—compliant chemical 

milling maskants. For those 

uncontrolled chemical milling maskants 

complying with the chemical milling 

maskant VOC content limit specified in 

§ 63.747(c)(2) without being averaged, 

the procedure specified in paragraphs 

(m)(1) and (2) of this section shall be 

used to determine the mass of VOC 

emitted per volume of chemical milling 

maskant (less water and exempt 

solvents) as applied. As an alternative to 

the procedures in paragraphs (m)(1) and 

(2) of this section, an owner or operator 

may use coating manufacturer’s 

supplied data to demonstrate that VOC 

emitted per volume of coating (less 

water and exempt solvents), as applied, 

is less than or equal to the applicable 

VOC limit specified in § 63.747(c). 

* * * * * 

(o) Inorganic HAP emissions—dry 

particulate filter certification 

requirements. Dry particulate filters 

used to comply with § 63.745(g)(2) or 

§ 63.746(b)(4) must be certified by the 

filter manufacturer or distributor, paint/ 

depainting booth supplier and/or the 

facility owner or operator using method 

319 in appendix A of this part, to meet 

or exceed the efficiency data points 

found in Tables 2 and 3 or 4 and 5 of 

§ 63.745 for existing or new sources 

respectively. 

■ 10. Section 63.751 is amended by 

revising paragraph (c) to read as follows: 

§ 63.751 Monitoring requirements. 

* * * * * 

(c) Dry particulate filter, HEPA filter 

and waterwash systems—primer, 

topcoat and specialty coating 

application operations. (1) Each owner 

or operator using a dry particulate filter 

system to meet the requirements of 

§ 63.745(g)(2) shall, while primer, 

topcoat and specialty coating 

application operations are occurring, 

continuously monitor the pressure drop 

across the system and read and record 

the pressure drop once per shift 

following the recordkeeping 

requirements of § 63.752(d). 

(2) Each owner or operator using a 

conventional waterwash system to meet 

the requirements of § 63.745(g)(2) shall, 

while primer or topcoat application 

operations are occurring, continuously 

monitor the water flow rate through the 

system and read and record the water 

flow rate once per shift following the 

recordkeeping requirements of 

§ 63.752(d). Each owner or operator 

using a pumpless waterwash system to 

meet the requirements of § 63.745(g)(2) 

shall, while primer, topcoat and 

specialty coating application operations 

are occurring, measure and record the 

parameter(s) recommended by the booth 

manufacturer that indicate booth 

performance once per shift, following 

the recordkeeping requirements of 

§ 63.752(d). 

* * * * * 

■ 11. Section 63.752 is amended by: 

■ a. Revising paragraph (a); 

■ b. Revising paragraphs (c) 

introductory text, (c)(1), (c)(2) 

introductory text, (c)(4) introductory 

text, (c)(5) introductory text and (c)(6) 

introductory text; 

■ c. Revising paragraphs (d) paragraph 

heading and (d)(1); and 

■ d. Revising paragraph (f) introductory 

text. 

The revisions read as follows: 

§ 63.752 Recordkeeping requirements. 

(a) General. Each owner or operator of 

a source subject to this subpart shall 

fulfill all recordkeeping requirements 

specified in § 63.10 (a), (b), (d) and (f), 

except § 63.10(b)(2)(i), (iv), and (v). Each 

owner or operator must also record and 

maintain according to § 63.10(b)(1) the 

information specified in paragraph (a)(1) 

through (3) of this section. 

(1) In the event that an affected unit 

fails to meet an applicable standard, 

record the number of failures. For each 

failure record the date, time and 

duration of each failure. 

(2) For each failure to meet an 

applicable standard, record and retain a 

list of the affected sources or equipment, 

an estimate of the quantity of each 

regulated pollutant emitted over any 

emission limit and a description of the 

method used to estimate the emissions. 

(3) Record actions taken to minimize 

emissions in accordance with 

§ 63.743(e), and any corrective actions 

taken to return the affected unit to its 

normal or usual manner of operation. 

* * * * * 

(c) Primer, topcoat and specialty 

coating application operations—organic 

HAP and VOC. Each owner or operator 

required to comply with the organic 

HAP and VOC content limits specified 

in § 63.745(c) shall record the 

information specified in paragraphs 

(c)(1) through (6) of this section, as 

appropriate. Each owner and operator 

using coating manufacturer’s supplied 

data to demonstrate compliance with 

the applicable organic HAP or VOC 

limit specified in § 63.745(c) may retain 

the manufacturer’s documentation and 

annual purchase records in place of the 

records specified in paragraphs (c)(2) 

and (3) of this section. 

(1) The name and VOC content as 

received and as applied of each primer, 

topcoat and specialty coating used at the 

facility. 

(2) For uncontrolled primers, topcoats 

and specialty coatings that meet the 

organic HAP and VOC content limits in 

§ 63.745(c)(1) through (6) without 

averaging: 

* * * * * 

(4) For primers, topcoats and specialty 

coatings complying with the organic 

HAP or VOC content level by averaging: 

* * * * * 

(5) For primers, topcoats and specialty 

coatings that are controlled by a control 

device other than a carbon adsorber: 

* * * * * 

(6) For primers, topcoats and specialty 

coatings that are controlled by a carbon 

adsorber: 

* * * * * 

(d) Primer, topcoat and specialty 

coating application operations— 

inorganic HAP emissions. (1) Each 

owner or operator complying with 

§ 63.745(g) for the control of inorganic 

HAP emissions from primer, topcoat 

and specialty coating application 

operations through the use of a dry 

particulate filter system or a HEPA filter 

system shall record the pressure drop 

across the operating system once each 

shift during which coating operations 

occur. 

(f) Chemical milling maskant 

application operations. Each owner or 

operator seeking to comply with the 

organic HAP and VOC content limits for 

the chemical milling maskant 

application operation, as specified in 

§ 63.747(c), or the control system 

requirements specified in § 63.747(d), 

shall record the information specified in 

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

section, as appropriate. Each owner and 

operator using coating manufacturer’s 

supplied data to demonstrate 

compliance with the applicable organic 

HAP or VOC limit specified in 

§ 63.747(c) may retain the 

manufacturer’s documentation and 

annual purchase records in place of the 

records specified in paragraph (f)(1) of 

this section. 

* * * * * 

■ 12. Section 63.753 is amended by: 

■ a. Revising paragraph (a)(1) 

introductory text and (a)(2); 

■ b. Adding paragraphs (a)(4) and (5); 

■ c. Revising paragraphs (c) 

introductory text, (c)(1)(i) and (ii). 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
8436 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

■ d. Revising paragraph (e)(1). 

The revisions and additions read as 

follows: 

§ 63.753 Reporting requirements. 

(a)(1) Except as provided in 

paragraphs (a)(2) through (5) of this 

section, each owner or operator subject 

to this subpart shall fulfill the 

requirements contained in § 63.9(a) 

through (e) and (h) through (j), 

Notification requirements and 

§ 63.10(a), (b), (d) and (f), Recordkeeping 

and reporting requirements, of the 

General Provisions, 40 CFR part 63, 

subpart A and that the initial 

notification for existing sources required 

in § 63.9(b)(2) shall be submitted not 

later than September 1, 1997, or as 

specified in § 63.9(b)(2). In addition to 

the requirements of § 63.9(h), the 

notification of compliance status shall 

include: 

* * * * * 

(2) The initial notification for existing 

sources, required in § 63.9(b)(2) shall be 

submitted no later than September 1, 

1997, or as specified in § 63.9(b)(2). For 

the purposes of this subpart, a title V or 

part 70 permit application may be used 

in lieu of the initial notification 

required under § 63.9(b)(2), provided 

the same information is contained in the 

permit application as required by 

§ 63.9(b)(2), and the State to which the 

permit application has been submitted 

has an approved operating permit 

program under part 70 of this chapter 

and has received delegation of authority 

from the EPA. Permit applications shall 

be submitted by the same due dates as 

those specified for the initial 

notifications. 

* * * * * 

(4) Each owner or operator subject to 

this subpart is not required to comply 

with § 63.10(b)(2)(i), (b)(2)(iv), (b)(2)(v), 

and (d)(5). 

(5) If a source fails to meet an 

applicable standard specified in 

§§ 63.744 through 63.748, report such 

events in the semiannual report: 

(i) The number of failures to meet an 

applicable standard. 

(ii) For each instance, report the date, 

time and duration of each failure. 

(iii) For each failure the report must 

include a list of the affected sources or 

equipment, an estimate of the quantity 

of each regulated pollutant emitted over 

any emission limit and a description of 

the method used to estimate the 

emissions. 

* * * * * 

(c) Primer, topcoat and specialty 

coating application operations. Each 

owner or operator of a primer or topcoat 

application operation subject to this 

subpart shall submit the following 

information: 

(1) * * * 

(i) For primers, topcoats and specialty 

coatings where compliance is not being 

achieved through the use of averaging or 

a control device, the HAP or VOC 

content in manufacturer’s supplied data 

as recorded under § 63.752(c), or each 

value of Hi and Gi as recorded under 

§ 63.752(c)(2)(i), that exceeds the 

applicable organic HAP or VOC content 

limit specified in § 63.745(c); 

(ii) For primers, topcoats and 

specialty coatings where compliance is 

being achieved through the use of 

averaging, each value of Ha and Ga, as 

recorded under § 63.752(c)(4)(i), that 

exceeds the applicable organic HAP or 

VOC content limit specified in 

§ 63.745(c); 

* * * * * 

(e) * * * 

(1) For chemical milling maskants 

where compliance is not being achieved 

through the use of averaging or a control 

device, the HAP or VOC content in 

manufacturer’s supplied data as 

recorded under § 63.752(f), or each 

value of Hi and Gi as recorded under 

§ 63.752(f)(1)(i), that exceeds the 

applicable organic HAP or VOC content 

limit specified in § 63.747(c); 

* * * * * 

■ 13. Revise Table 1 to Subpart GG of 

Part 63 to read as follows: 

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

Reference Applies to affected sources 

in subpart GG Comment 

63.1(a)(1) .......................................................................... Yes. 

63.1(a)(2) .......................................................................... Yes. 

63.1(a)(3) .......................................................................... Yes. 

63.1(a)(4) .......................................................................... Yes. 

63.1(a)(5) .......................................................................... No ....................................... Reserved. 

63.1(a)(6) .......................................................................... Yes. 

63.1(a)(7) .......................................................................... Yes. 

63.1(a)(8) .......................................................................... Yes. 

63.1(a)(9) .......................................................................... No ....................................... Reserved. 

63.1(a)(10) ........................................................................ Yes. 

63.1(a)(11) ........................................................................ Yes. 

63.1(a)(12) ........................................................................ Yes. 

63.1(a)(13) ........................................................................ Yes. 

63.1(a)(14) ........................................................................ Yes. 

63.1(b)(1) .......................................................................... Yes. 

63.1(b)(2) .......................................................................... Yes. 

63.1(b)(3) .......................................................................... Yes. 

63.1(c)(1) .......................................................................... Yes. 

63.1(c)(2) .......................................................................... Yes ..................................... Subpart GG does not apply to area sources. 

63.1(c)(3) .......................................................................... No ....................................... Reserved. 

63.1(c)(4) .......................................................................... Yes. 

63.1(c)(5) .......................................................................... Yes. 

63.1(d) ............................................................................... No ....................................... Reserved. 

63.1(e) ............................................................................... Yes. 

63.2 ................................................................................... Yes. 

63.3 ................................................................................... Yes. 

63.4(a)(1) .......................................................................... Yes. 

63.4(a)(2) .......................................................................... Yes. 

63.4(a)(3) .......................................................................... Yes. 

63.4(a)(4) .......................................................................... No ....................................... Reserved. 

63.4(a)(5) .......................................................................... Yes. 


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TABLE 1 TO SUBPART GG OF PART 63—GENERAL PROVISIONS APPLICABILITY TO SUBPART GG—Continued 

Reference Applies to affected sources 

in subpart GG Comment 

63.4(b) ............................................................................... Yes. 

63.4(c) ............................................................................... Yes. 

63.5(a) ............................................................................... Yes. 

63.5(b)(1) .......................................................................... Yes. 

63.5(b)(2) .......................................................................... No ....................................... Reserved. 

63.5(b)(3) .......................................................................... Yes. 

63.5(b)(4) .......................................................................... Yes. 

63.5(b)(5) .......................................................................... Yes. 

63.5(b)(6) .......................................................................... Yes. 

63.5(c) ............................................................................... No ....................................... Reserved. 

63.5(d)(1)(i) ....................................................................... Yes. 

63.5(d)(1)(ii)(A) through (H) .............................................. Yes. 

63.5(d)(1)(ii)(I) ................................................................... No ....................................... Reserved. 

63.5(d)(1)(ii)(J) .................................................................. Yes. 

63.5(d)(1)(iii) ..................................................................... Yes. 

63.5(d)(2) through (4) ....................................................... Yes. 

63.5(e) ............................................................................... Yes. 

63.5(f) ................................................................................ Yes. 

63.6(a) ............................................................................... Yes. 

63.6(b)(1) through (5) ....................................................... Yes ..................................... § 63.749(a) specifies compliance dates for new 

sources. 

63.6(b)(6) .......................................................................... No ....................................... Reserved. 

63.6(b)(7) .......................................................................... Yes. 

63.6(c)(1) .......................................................................... Yes. 

63.6(c)(2) .......................................................................... No ....................................... The standards in subpart GG are promulgated under 

section 112(d) of the CAA. 

63.6(c)(3) and (4) .............................................................. No ....................................... Reserved. 

63.6(c)(5) .......................................................................... Yes. 

63.6(d) ............................................................................... No ....................................... Reserved. 

63.6(e)(1)(i) ....................................................................... No ....................................... See § 63.743(e) for general duty requirement. 

63.6(e)(1)(ii) ...................................................................... No. 

63.6(e)(2) .......................................................................... No ....................................... Section reserved. 

63.6(e)(3) .......................................................................... No. 

63.6(f)(1) ........................................................................... No. 

63.6(f)(2) and (3) .............................................................. Yes. 

63.6(g) ............................................................................... Yes. 

63.6(h) ............................................................................... No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.6(i)(1) and (3) ............................................................... Yes. 

63.6(i)(4)(i)(A) ................................................................... Yes. 

63.6(i)(4)(i)(B) ................................................................... No ....................................... § 63.743(a)(4) specifies that requests for extension of 

compliance must be submitted no later than 120 

days before an affected source’s compliance date. 

63.6(i)(4)(ii) ....................................................................... No ....................................... The standards in subpart GG are promulgated under 

section 112(d) of the CAA. 

63.6(i)(5) through (12) ...................................................... Yes. 

63.6(i)(13) ......................................................................... Yes. 

63.6(i)(14) ......................................................................... Yes. 

63.6(i)(15) ......................................................................... No ....................................... Reserved. 

63.6(i)(16) ......................................................................... Yes. 

63.6(j) ................................................................................ Yes. 

63.7(a)(1) .......................................................................... Yes. 

63.7(a)(2)(i) through (vi) ................................................... Yes. 

63.7(a)(2)(vii) and (viii) ..................................................... No ....................................... Reserved. 

63.7(a)(2)(ix) ..................................................................... Yes. 

63.7(a)(3) .......................................................................... Yes. 

63.7(b) ............................................................................... Yes. 

63.7(c) ............................................................................... Yes. 

63.7(d) ............................................................................... Yes. 

63.7(e)(1) .......................................................................... No ....................................... See § 63.749(j). 

63.7(e)(2) through (4) ....................................................... Yes. 

63.7(f) ................................................................................ Yes. 

63.7(g)(1) .......................................................................... Yes. 

63.7(g)(2) .......................................................................... No ....................................... Reserved. 

63.7(g)(3) .......................................................................... Yes. 

63.7(h) ............................................................................... Yes. 

63.8(a)(1) and (2) ............................................................. Yes. 

63.8(a)(3) .......................................................................... No ....................................... Reserved. 

63.8(a)(4) .......................................................................... Yes. 

63.8(b) ............................................................................... Yes. 

63.8(c)(1)(i) ....................................................................... No. 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
8438 Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 

TABLE 1 TO SUBPART GG OF PART 63—GENERAL PROVISIONS APPLICABILITY TO SUBPART GG—Continued 

Reference Applies to affected sources 

in subpart GG Comment 

63.8(c)(1)(ii) ...................................................................... Yes. 

63.8(c)(1)(iii) ...................................................................... No. 

63.8(c)(2) through (d)(2) ................................................... Yes. 

63.8(d)(3) .......................................................................... No. 

63.8(e)(1) through (4) ....................................................... Yes. 

63.8(e)(5)(i) ....................................................................... Yes. 

63.8(e)(5)(ii) ...................................................................... No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.8(f)(1) ........................................................................... Yes. 

63.8(f)(2)(i) through (vii) .................................................... Yes. 

63.8(f)(2)(viii) ..................................................................... No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.8(f)(2)(ix) ...................................................................... Yes. 

63.8(f)(3) through (6) ........................................................ Yes. 

63.8(g) ............................................................................... Yes. 

63.9(a) ............................................................................... Yes. 

63.9(b)(1) .......................................................................... Yes. 

63.9(b)(2) .......................................................................... Yes ..................................... § 63.753(a)(1) requires submittal of the initial notification at least 1 year prior to the compliance date; 

§ 63.753(a)(2) allows a title V or part 70 permit application to be substituted for the initial notification in 

certain circumstances. 

63.9(b)(3) .......................................................................... Yes. 

63.9(b)(4) .......................................................................... Yes. 

63.9(b)(5) .......................................................................... Yes. 

63.9(c) ............................................................................... Yes. 

63.9(d) ............................................................................... Yes. 

63.9(e) ............................................................................... Yes. 

63.9(f) ................................................................................ No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.9(g)(1) .......................................................................... No. 

63.9(g)(2) .......................................................................... No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.9(g)(3) .......................................................................... No. 

63.9(h)(1) through (3) ....................................................... Yes ..................................... § 63.753(a)(1) also specifies additional information to 

be included in the notification of compliance status. 

63.9(h)(4) .......................................................................... No ....................................... Reserved. 

63.9(h)(5) and (6) ............................................................. Yes. 

63.9(i) ................................................................................ Yes. 

63.9(j) ................................................................................ Yes. 

63.10(a) ............................................................................. Yes. 

63.10(b)(1) ........................................................................ Yes. 

63.10(b)(2)(i) ..................................................................... No. 

63.10(b)(2)(ii) .................................................................... No ....................................... See § 63.752(a) for recordkeeping of: (1) Date, time 

and duration; (2) Listing of affected source or equipment and an estimate of the quantity of each regulated pollutant emitted over the standard; and (3) Actions to minimize emissions and correct the failure. 

63.10(b)(2)(iii) ................................................................... Yes. 

63.10(b)(2)(iv) and (v) ....................................................... No. 

63.10(b)(2)(vi) ................................................................... Yes. 

63.10(b)(2)(vi)(A) through (C) ........................................... No ....................................... § 63.10(b)(vii)(A), (B) and (C) do not apply because 

subpart GG does not require the use of CEMS. 

63.10(b)(2)(vii) through (xiv).

63.10(b)(3) ........................................................................ Yes. 

63.10(c)(1) ........................................................................ No. 

63.10(c)(2) through (4) ..................................................... No ....................................... Reserved. 

63.10(c)(5) and (6) ............................................................ No. 

63.10(c)(7) and (8) ............................................................ Yes. 

63.10(c)(9) ........................................................................ No ....................................... Reserved. 

63.10(c)(10) through (13) ................................................. No. 

63.10(c)(14) ...................................................................... No ....................................... § 63.8(d) does not apply to this subpart. 

63.10(c)(15) ...................................................................... No. 

63.10(d)(1) and (2) ........................................................... Yes. 

63.10(d)(3) ........................................................................ No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.10(d)(4) ........................................................................ Yes. 

63.10(d)(5) ........................................................................ No. See § 63.753 (a)(5) for 

malfunction reporting requirements..

63.(10)(e)(1) ...................................................................... No. 


tkelley on DSK3SPTVN1PROD with PROPOSALS2
Federal Register / Vol. 80, No. 31 / Tuesday, February 17, 2015 / Proposed Rules 8439 

TABLE 1 TO SUBPART GG OF PART 63—GENERAL PROVISIONS APPLICABILITY TO SUBPART GG—Continued 

Reference Applies to affected sources 

in subpart GG Comment 

63.10(e)(2)(i) ..................................................................... No. 

63.10(e)(2)(ii) .................................................................... No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.10(e)(3) ........................................................................ No. 

63.10(e)(4) ........................................................................ No ....................................... The standards in subpart GG do not include opacity 

standards. 

63.10(f) .............................................................................. Yes. 

63.11 ................................................................................. Yes. 

63.12 ................................................................................. Yes. 

63.13 ................................................................................. Yes. 

63.14 ................................................................................. Yes. 

63.15 ................................................................................. Yes. 

63.16 ................................................................................. Yes. 

[FR Doc. 2015–02055 Filed 2–13–15; 8:45 am] 

BILLING CODE 6560–50–P 


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