Vol. 78 Monday, 

No. 213 November 4, 2013 

Part II 

Environmental Protection Agency 

40 CFR Part 63 

National Emissions Standards for Hazardous Air Pollutants Residual Risk 

and Technology Review for Flexible Polyurethane Foam Production; 

Proposed Rule 


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ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 63 

[EPA–HQ–OAR–2012–0510; FRL–9900–94– 

OAR] 

RIN 2060–AR58 

National Emissions Standards for 

Hazardous Air Pollutants Residual 

Risk and Technology Review for 

Flexible Polyurethane Foam 

Production 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The EPA is proposing 

amendments to the National Emissions 

Standards for Hazardous Air Pollutants 

for Flexible Polyurethane Foam 

Production to address the results of the 

residual risk and technology review. In 

light of our review, we are proposing 

amendments that would prohibit the 

use of hazardous air pollutant-based 

auxiliary blowing agents for slabstock 

foam production facilities. In addition, 

the EPA is proposing amendments to 

correct and clarify regulatory provisions 

related to emissions during periods of 

startup, shutdown and malfunction; to 

add provisions for affirmative defense; 

to add requirements for reporting of 

performance testing through the 

Electronic Reporting Tool; to revise 

compliance dates for applicable 

proposed actions; to clarify the leak 

detection methods allowed for 

diisocyanate storage vessels at slabstock 

foam production facilities; and to revise 

the rule to add a schedule for delay of 

leak repairs for valves and connectors. 

DATES:

Comments. Comments must be 

received on or before December 4, 2013. 

A copy of comments on the information 

collection provisions should be 

submitted to the Office of Management 

and Budget (OMB) on or before 

December 4, 2013. 

Public Hearing. If anyone contacts the 

EPA requesting a public hearing by 

November 14, 2013, the public hearing 

will be held on November 20, 2013, 

from 10:00 a.m. to 4:00 p.m. on the EPA 

campus at 109 T.W. Alexander Drive in 

Research Triangle Park, North Carolina. 

If 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: Submit your comments, 

identified by Docket ID Number EPA– 

HQ–OAR–2012–0510, by one of the 

following methods: 

• http://www.regulations.gov: Follow 

the on-line instructions for submitting 

comments. 

• Email: a-and-r-Docket@epa.gov, 

Attention Docket ID Number EPA–EPA– 

HQ–OAR–2012–0510. 

• Fax: (202) 566–9744, Attention 

Docket ID Number EPA–HQ–OAR– 

2012–0510. 

• Mail: U.S. Postal Service, send 

comments to: EPA Docket Center, EPA 

West (Air Docket), Attention Docket ID 

Number EPA–HQ–OAR–2012–0510, 

U.S. Environmental Protection Agency, 

Mailcode: 2822T, 1200 Pennsylvania 

Ave. NW., Washington, DC 20460. 

Please include a total of two copies. In 

addition, please mail a copy of your 

comments on the information collection 

provisions to the Office of Information 

and Regulatory Affairs, Office of 

Management and Budget, Attn: Desk 

Officer for EPA, 725 17th Street NW., 

Washington, DC 20503. 

• Hand Delivery: U.S. Environmental 

Protection Agency, EPA West (Air 

Docket), Room 3334, 1301 Constitution 

Ave. NW., Washington, DC 20004, 

Attention Docket ID Number EPA–HQ– 

OAR–2012–0510. 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 Number EPA–HQ–OAR– 

2012–0510. 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 Number EPA–HQ–OAR–2012–0510. 

All documents in the docket are listed 

in the regulations.gov index. Although 

listed in the index, some information is 

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

information whose disclosure is 

restricted by statute. Certain other 

material, such as copyrighted material, 

is not placed on the Internet and will be 

publicly available only in hard copy. 

Publicly available docket materials are 

available either electronically in 

regulations.gov or in hard copy at the 

EPA Docket Center, EPA West, Room 

3334, 1301 Constitution Ave. NW., 

Washington, DC. The Public Reading 

Room is open from 8:30 a.m. to 4:30 

p.m., Monday through Friday, excluding 

legal holidays. The telephone number 

for the Public Reading Room is (202) 

566–1744, and the telephone number for 

the EPA Docket Center is (202) 566– 

1742. 

Public Hearing. If anyone contacts the 

EPA requesting a public hearing by 

November 14, 2013, the public hearing 

will be held on November 20, 2013, 

from 10:00 a.m. to 4:00 p.m. on the EPA 

campus at 109 T.W. Alexander Drive in 

Research Triangle Park, North Carolina. 

Persons interested in presenting oral 

testimony or inquiring as to whether a 

public hearing will be held should 

contact Ms. Pamela Garrett, Sector 

Policies and Programs Division (D243– 

01), Office of Air Quality Planning and 

Standards, U.S. Environmental 

Protection Agency, Research Triangle 

Park, North Carolina 27711; telephone 

number: (919) 541–7966; fax number: 

(919) 541–5450; and email address: 

garrett.pamela@epa.gov. 

FOR FURTHER INFORMATION CONTACT: For 

questions about this proposed action, 

contact Ms. Kaye Whitfield, 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) 541–2509; fax number: 

(919) 541–5450; and email address: 

whitfield.kaye@epa.gov. For specific 

information regarding the risk modeling 


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1U.S. EPA, 1992. Documentation for Developing 

the Initial Source Category List—Final Report. EPA– 

450/3–91–030. 

methodology, contact Mr. Chris 

Sarsony, 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– 

4843; fax number: (919) 541–0840; and 

email address: sarsony.chris@epa.gov. 

For information about the applicability 

of the National Emission Standards for 

Hazardous Air Pollutants (NESHAP) to 

a particular entity, contact Mr. Scott 

Throwe, Office of Enforcement and 

Compliance Assurance; telephone 

number: (202) 564–7013; fax number: 

(202) 564–0050; and email address: 

throwe.scott@epa.gov. 

SUPPLEMENTARY INFORMATION:

Preamble Acronyms and Abbreviations 

This preamble includes several 

acronyms and terms used to describe 

industrial processes, data inventories 

and risk modeling. 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: 

ABA auxiliary blowing agent 

AEGL acute exposure guideline levels 

AERMOD air dispersion model used by the 

HEM–3 model 

BAAQMD Bay Area Air Quality 

Management District 

CAA Clean Air Act 

CalEPA California EPA 

CBI Confidential Business Information 

CDX Central Data Exchange 

CEDRI Compliance and Emissions Data 

Reporting Interface 

CFR Code of Federal Regulations 

EIS Emission Inventory System 

EPA Environmental Protection Agency 

ERPG Emergency Response Planning 

Guidelines 

ERT Electronic Reporting Tool 

FPUF Flexible Polyurethane Foam 

FR Federal Register 

HAP hazardous air pollutants 

HCl hydrogen chloride 

HEM–3 Human Exposure Model, Version 

1.1.0 

HI hazard index 

HF hydrogen fluoride 

HQ hazard quotient 

ICR information collection request 

IRIS Integrated Risk Information System 

kg kilogram 

km kilometer 

lb pound 

LDAR leak detection and repair 

MACT maximum achievable control 

technology 

MACT Code Code within the National 

Emissions Inventory used to identify 

processes included in a source category 

mg/kg-day milligrams per kilogram per day 

mg/m3 milligrams per cubic meter 

MIR maximum individual risk 

NAICS North American Industry 

Classification System 

NEI National Emissions Inventory 

NESHAP National Emissions Standards for 

Hazardous Air Pollutants 

NRC National Research Council 

NRDC Natural Resources Defense Council 

NTTAA National Technology Transfer and 

Advancement Act 

OAQPS Office of Air Quality Planning and 

Standards 

OMB Office of Management and Budget 

PB–HAP hazardous air pollutants known to 

be persistent and bio-accumulative in the 

environment 

POM polycyclic organic matter 

PFA Polyurethane Foam Association 

ppm parts per million 

QA quality assurance 

REL reference exposure level 

RCO recuperative thermal oxidizer 

RfC reference concentration 

RfD reference dose or daily oral exposure 

RTO regenerative thermal oxidizer 

RTR residual risk and technology review 

SAB Science Advisory Board 

SBA Small Business Administration 

S/L/Ts State, local, and tribal air pollution 

control agencies 

SOP standing operating procedures 

SSM startup, shutdown and malfunction 

TOSHI target organ-specific hazard index 

tpy tons per year 

TRI Toxics Release Inventory 

TRIM Total Risk Integrated Methodology 

TTN Technology Transfer Network 

UF uncertainty factors 

mg/m3 microgram per cubic meter 

UMRA Unfunded Mandates Reform Act 

URE unit risk estimate 

VCS voluntary consensus standards 

WWW world wide web 

Organization of this Document. The 

information in this preamble is 

organized as follows: 

I. General Information 

A. Does this action apply to me? 

B. Where can I get a copy of this document 

and other related information? 

C. What should I consider as I prepare my 

comments for the EPA? 

II. Background 

A. What is the statutory authority for this 

action? 

B. What is this source category and how do 

the MACT standards regulate its HAP 

emissions? 

C. What data collection activities were 

conducted to support this 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? 

D. What other analyses and reviews were 

conducted in support of this proposal 

and how did we conduct those analyses 

and reviews? 

IV. Analytical Results and Proposed 

Decisions 

A. What are the results of the risk 

assessment and analyses? 

B. What are our proposed decisions 

regarding risk acceptability, ample 

margin of safety and adverse 

environmental effects? 

C. What are the results and proposed 

decisions based on our technology 

review? 

D. What other actions are we proposing? 

E. What compliance dates are we 

proposing? 

V. Summary of Cost, Environmental and 

Economic Impacts 

A. What are the 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 

D. Unfunded Mandates Reform Act 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer and 

Advancement Act 

J. Executive Order 12898: Federal Actions To 

Address Environmental Justice in 

Minority Populations and Low-Income 

Populations 

I. General Information 

A. Does this action apply to me? 

Table 1 of this preamble lists the 

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 finalized, will be directly 

applicable to the affected sources. One 

federal entity is affected by this 

proposed action, and no state, local or 

tribal government entities are affected 

by this proposed action. As defined in 

the ‘‘Initial List of Categories of Sources 

Under Section 112(c)(1) of the Clean Air 

Act Amendments of 1990’’ (see 57 FR 

31576, July 16, 1992), the ‘‘Flexible 

Polyurethane Foam Production’’ source 

category is any facility engaged in the 


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450/3–91–030. 

manufacture of foam made from a 

polymer containing a plurality of 

carbamate linkages in the chain 

backbone (polyurethane).1

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

Source category NESHAP NAICS 

code a

Flexible Polyurethane Foam Production ....................................... Flexible Polyurethane Foam Production ..................................... 326150 

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 on the TTN’s policy and 

guidance page for newly proposed or 

promulgated rules at: http://

www.epa.gov/ttn/oarpg/t3pfpr.html. 

Following publication in the Federal 

Register, the EPA will post the Federal 

Register version of the proposal and key 

technical documents on the project Web 

site: http://www.epa.gov/ttn/atw/foam/

foampg.html. Information on the overall 

residual risk and technology review 

(RTR) 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: Roberto 

Morales, OAQPS Document Control 

Officer (C404–02), OAQPS, U.S. 

Environmental Protection Agency, 

Research Triangle Park, North Carolina 

27711, Attention Docket ID Number 

EPA–HQ–OAR–2012–0510. 

II. Background 

A. What is the statutory authority for 

this action? 

Section 112 of the Clean Air Act 

(CAA) establishes a two-stage regulatory 

process to address emissions of 

hazardous air pollutants (HAP) from 

stationary sources. In the first stage, 

after the EPA has identified categories of 

sources emitting one or more of the HAP 

listed in CAA section 112(b), CAA 

section 112(d) requires us to promulgate 

technology-based NESHAP for those 

sources. ‘‘Major sources’’ are those that 

emit or have the potential to emit 10 

tons per year (tpy) or more of a single 

HAP or 25 tpy or more of any 

combination of HAP. For major sources, 

the technology-based NESHAP must 

reflect the maximum degree of 

emissions reductions of HAP achievable 

(after considering cost, energy 

requirements and non-air quality health 

and environmental impacts) and are 

commonly referred to as maximum 

achievable control technology (MACT) 

standards. 

MACT standards must reflect the 

maximum degree of emissions reduction 

achievable through the application of 

measures, processes, methods, systems 

or techniques, including, but not limited 

to, measures that (1) reduce the volume 

of or eliminate pollutants through 

process changes, substitution of 

materials or other modifications; (2) 

enclose systems or processes to 

eliminate emissions; (3) capture or treat 

pollutants when released from a 

process, stack, storage or fugitive 

emissions point; (4) are design, 

equipment, work practice or operational 

standards (including requirements for 

operator training or certification); or (5) 

are a combination of the above. CAA 

section 112(d)(2)(A)-(E). The MACT 

standards may take the form of design, 

equipment, work practice or operational 

standards where the EPA first 

determines either that (1) a pollutant 

cannot be emitted through a conveyance 

designed and constructed to emit or 

capture the pollutant, or that any 

requirement for, or use of, such a 

conveyance would be inconsistent with 

law; or (2) the application of 

measurement methodology to a 

particular class of sources is not 

practicable due to technological and 

economic limitations. CAA section 

112(h)(1)–(2). 

The MACT ‘‘floor’’ is the minimum 

control level allowed for MACT 

standards promulgated under CAA 

section 112(d)(3) and may not be based 

on cost considerations. For new sources, 

the MACT floor cannot be less stringent 

than the emissions control that is 

achieved in practice by the bestcontrolled similar source. The MACT 

floor for existing sources can be less 

stringent than floors for new sources but 

not less stringent than the average 

emissions limitation achieved by the 

best-performing 12 percent of existing 

sources in the category or subcategory 

(or the best-performing five sources for 

categories or subcategories with fewer 

than 30 sources). In developing MACT 

standards, the EPA must also consider 

control options that are more stringent 

than the floor. We may establish 

standards more stringent than the floor 

based on considerations of the cost of 

achieving the emissions reductions, any 

non-air quality health and 

environmental impacts and energy 

requirements. 

The EPA is then required to review 

these technology-based standards and 

revise them ‘‘as necessary (taking into 

account developments in practices, 

processes and control technologies)’’ no 


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less frequently than every eight 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). This provision requires, 

first, 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. 

Congress did not act in response, 

thereby triggering the EPA’s obligation 

under CAA section 112(f)(2) to analyze 

and address residual risk. 

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 standards 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 this process 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, which 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. Determining Acceptability 

The agency in the Benzene NESHAP 

concluded that ‘‘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.’’ Id. 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. We discussed the maximum 

individual lifetime cancer risk (or 

maximum individual risk (MIR)) as 

being ‘‘the estimated risk that a person 

living near a plant would have if he or 

she were exposed to the maximum 

pollutant concentrations for 70 years.’’ 

Id. We explained that this measure of 

risk ‘‘is an estimate of the upper bound 

of risk based on conservative 

assumptions, such as continuous 

exposure for 24 hours per day for 70 

years.’’ Id. We acknowledged that 

maximum individual lifetime cancer 

risk ‘‘does not necessarily reflect the 

true risk, but displays a conservative 

risk level which is an upper-bound that 

is unlikely to be exceeded.’’ Id. 

Understanding that there are both 

benefits and limitations to using the 

MIR as a metric for determining 

acceptability, we acknowledged in the 

Benzene NESHAP that ‘‘consideration of 

maximum individual risk * * * must 

take into account the strengths and 

weaknesses of this measure of risk.’’ Id. 

Consequently, the presumptive risk 

level of 100-in-1 million (1-in-10 

thousand) provides a benchmark for 

judging the acceptability of maximum 

individual lifetime cancer risk, but does 

not constitute a rigid line for making 

that determination. Further, in the 

Benzene NESHAP, we noted that: 

[p]articular attention will also be accorded to 

the weight of evidence presented in the risk 

assessment of potential carcinogenicity or 

other health effects of a pollutant. While the 

same numerical risk may be estimated for an 

exposure to a pollutant judged to be a known 

human carcinogen, and to a pollutant 

considered a possible human carcinogen 

based on limited animal test data, the same 

weight cannot be accorded to both estimates. 

In considering the potential public health 

effects of the two pollutants, the Agency’s 

judgment on acceptability, including the 

MIR, will be influenced by the greater weight 

of evidence for the known human 

carcinogen. 

Id. at 38046. The agency also explained 

in the Benzene NESHAP that: 

[i]n establishing a presumption for MIR, 

rather than a rigid line for acceptability, the 

Agency intends to weigh it with a series of 

other health measures and factors. These 

include the overall incidence of cancer or 

other serious health effects within the 

exposed population, the numbers of persons 

exposed within each individual lifetime risk 

range and associated incidence within, 

typically, a 50 km exposure radius around 

facilities, the science policy assumptions and 

estimation uncertainties associated with the 

risk measures, weight of the scientific 

evidence for human health effects, other 

quantified or unquantified health effects, 

effects due to co-location of facilities, and coemission of pollutants. 

Id. At 38045. In some cases, these health 

measures and factors taken together may 

provide a more realistic description of 

the magnitude of risk in the exposed 

population than that provided by 

maximum individual lifetime cancer 

risk alone. 

As noted earlier, in NRDC v. EPA, the 

court held that 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. Determination of Ample Margin of 

Safety 

CAA section 112(f)(2) requires the 

EPA to determine, for source categories 

subject to MACT standards, whether 


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2 ‘‘Adverse environmental effect’’ is defined as 

any significant and widespread adverse effect, 

which may be reasonably anticipated to wildlife, 

aquatic life or natural resources, including adverse 

impacts on populations of endangered or threatened 

species or significant degradation of environmental 

qualities over broad areas. CAA section 112(a)(7). 

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. 

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,2 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, 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. 

B. What is this source category and how 

do the MACT standards regulate its 

HAP emissions? 

The MACT standards for Flexible 

Polyurethane Foam (FPUF) Production 

were promulgated on October 7, 1998, 

(63 FR 53980) and codified at 40 CFR 

part 63, subpart III. The FPUF 

Production MACT standards apply to 

each new and existing flexible 

polyurethane foam or rebond foam 

process that produces flexible 

polyurethane foam or rebond foam, 

emits HAP, and is located at a 

contiguous, major source plant site. The 

requirements of the standards are the 

same for both new and existing sources. 

There are three types of FPUF 

producers in the source category: 

Slabstock, molded and rebond. 

Slabstock foam is produced in large 

continuous buns that are then cut into 

the desired size and shape. Slabstock 

foam products are primarily used in 

furniture seat cushions and bedding 

materials. Molded foam is produced by 

‘‘shooting’’ the foam mixture into a 

mold of the desired shape and size. 

Molded foam is typically used in 

automotive seats, packaging and a range 

of specialty products. Rebond foam is 

made from scrap foam that is converted 

into a material primarily used for carpet 

underlay. Rebond foam production is 

often co-located with slabstock foam 

production facilities. 

Slabstock and molded polyurethane 

foams are produced by mixing three 

major ingredients: A polyol polymer, an 

isocyanate and water. The polyol is 

either a polyether or polyester polymer 

with hydroxyl end groups. Other 

ingredients are often added to modify 

the polymer, and catalysts are used to 

balance the principal foam production 

reactions. Auxiliary blowing agents 

(ABAs) may be used to produce specific 

densities and grades of foam where the 

gases produced by the isocyanate-water 

reaction are insufficient to achieve the 

desired density. ABAs are more widely 

used in the production of slabstock 

foams than in the production of molded 

foams. Rebond foam is produced from 

scrap slabstock or molded polyurethane 

foam. 

The HAP emission points at FPUF 

production facilities depend on the type 

of foam being produced. Prior to 

compliance with the original FPUF 

Production MACT standards, the 

primary HAP emission point for 

slabstock foam facilities was the foam 

production line, due to emissions of 

HAP ABAs. Other HAP emission points 

at slabstock production facilities 

include storage vessels and equipment 

leaks. At molded and rebond foam 

facilities, the primary HAP emission 

points are storage vessels and 

equipment leaks. 

Many facilities discontinued use of 

HAP ABAs before the rule’s October 

2001 compliance date, allowing these 

facilities to be designated as area 

sources. Based on the best information 

available, slabstock production facilities 

using HAP ABAs on, or after, the rule’s 

October 2001 compliance date also have 

discontinued use of HAP-based ABAs. 

We solicit comment on the use of HAPbased ABAs and whether any facilities 

in the FPUF production source category 

currently use these products. 

In the past decade, the FPUF 

production source category has 

experienced plant closures and 

consolidations. Today, there are 13 

FPUF production facilities subject to the 

MACT standards: 7 slabstock, 6 molded 

and 2 rebond. One rebond facility is colocated with a slabstock facility, and the 

other rebond facility is co-located with 

a molded foam facility. A list of these 

facilities is included in the 

memorandum, Development of the RTR 


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3U.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. 

Emissions Dataset for the Flexible 

Polyurethane Foam Production Source 

Category, which is available in the 

docket for this proposed rulemaking. 

The FPUF Production MACT 

standards contain requirements specific 

for each of the three types of foam 

production processes. For slabstock 

foam production, the FPUF Production 

MACT standards include diisocyanate 

and HAP ABA emissions reduction 

requirements. For molded and rebond 

foam production, the FPUF Production 

MACT standards prohibit the use of 

HAP in mold release agents and 

equipment cleaners, except in very 

limited circumstances. 

For slabstock foam production, the 

FPUF Production MACT standards 

regulate emissions of diisocyanates from 

storage vessels, transfer pumps and 

equipment leaks. The storage vessel 

requirements include the installation of 

either a vapor recovery system or a 

carbon adsorption system. Transfer 

pumps are required to be either sealless 

pumps or pumps submerged in a neutral 

oil, and submerged pumps must be 

visually inspected periodically for leaks. 

All components in diisocyanate service 

must be repaired when a leak is 

detected. 

Standards for HAP ABA emissions at 

slabstock facilities include emission 

point requirements for the foam 

production line, storage vessels, 

equipment leaks and equipment 

cleaning. For the slabstock production 

line, the FPUF Production MACT 

standards contain restrictions on the 

amount of HAP ABAs that can be used, 

based on the grades of foam produced. 

The FPUF Production MACT standards 

also regulate HAP ABAs by requiring 

installation of either a vapor recovery 

system or a carbon adsorption system on 

storage vessels. For equipment leaks, the 

FPUF Production MACT standards 

require a leak detection and repair 

program (LDAR) for HAP ABAs. The use 

of HAP or HAP-based products for 

equipment cleaning is prohibited at 

slabstock flexible polyurethane foam 

production facilities. This proposed rule 

also includes an alternative source-wide 

HAP ABA emission limit. The sourcewide emission limit allows slabstock 

facilities to comply by limiting the total 

amount of a single HAP ABA used, 

rather than by complying with the 

individual HAP ABA emission point 

requirements (e.g., production line, 

LDAR, equipment cleaning). 

For molded foam and rebond foam 

production, the FPUF Production 

MACT standards prohibit the use of 

HAP-based products as mold release 

agents and as equipment cleaners, 

except that diisocyanates may be used 

to flush the mixhead and associated 

piping during startup and maintenance 

if the diisocyanates are contained in a 

closed-loop system and re-used in 

production. 

C. What data collection activities were 

conducted to support this action? 

In 2011, we surveyed nine companies 

that own and operate foam production 

facilities, as provided for under section 

114 of the CAA. We also conducted 

plant visits to four facilities in 2012 and 

2013, retrieved permit data from 

approximately 32 state agencies, and 

obtained emissions inventory data from 

state agencies. Finally, we reviewed 

data in four EPA emission inventory 

databases: National Emissions Inventory 

(NEI), Emissions Inventory System 

(EIS), Toxics Release Inventory (TRI) 

and Envirofacts to identify facilities that 

may be part of the source category, 

emission sources and quantities of 

emissions. The CAA section 114 

questionnaire included requests for 

available information regarding process 

equipment, control devices and work 

practices for emission reductions, point 

and fugitive emissions and other aspects 

of facility operations. 

The emissions data and risk 

assessment inputs for the FPUF 

production source category are 

described further in the memorandum 

Development of the RTR Emissions 

Dataset for the Flexible Polyurethane 

Foam Production Source Category, 

which is available in the docket for this 

proposed rulemaking. 

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 provided 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 provided estimates of the 

distribution of cancer risks within the 

exposed populations, cancer incidence 

and an evaluation of the potential for 

adverse environmental effects for the 

source category. The risk assessment 

consisted of eight primary steps, as 

discussed below. The docket for this 

rulemaking contains the following 

document, which provides more 

information on the risk assessment 

inputs and models: Draft Residual Risk 

Assessment for the Flexible 

Polyurethane Foam Production Source 

Category. The methods used to assess 

risks (as described in the eight primary 

steps below) are consistent with those 

peer-reviewed by a panel of the EPA’s 

Science Advisory Board (SAB) in 2009 

and described in their peer review 

report issued in 2010; 3 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 from the 13 existing FPUF 

production facilities were used to create 

a dataset that is the basis for the risk 

assessment. We estimated the amount of 

actual and allowable emissions using 

data collected through the CAA section 

114 request, emission inventories (EIS, 

NEI and TRI) and site visits. We 

performed quality assurance (QA) 

procedures for the emissions data and 

release characteristics to identify any 

outliers, and then confirmed or 

corrected the data. For facilities where 

speciated HAP data were unavailable or 

unreliable, more recent inventory data 

were obtained from state or local 

permitting agencies. In addition to the 

QA of the source data for the facilities 

contained in the dataset, we also 

checked the coordinates of every 

emission source in the dataset through 

visual observations using tools such as 

Google Earth and ArcView, and made 

corrections, as necessary. Further 

information about the development of 

the dataset is provided in the technical 

document: Draft Development of the 

RTR Emissions Dataset for the Flexible 

Polyurethane Foam Production Source 

Category, which is available in the 

docket for this action. 

2. How did we estimate MACTAllowable emissions? 

The available emissions data in the 

MACT dataset include estimates of the 

mass of HAP emitted during the 

specified annual time period. In some 

cases, these ‘‘actual’’ emission levels are 

lower than the emission levels a facility 

is allowed to emit and still 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. 

This represents the highest emissions 


EMCDONALD on DSK67QTVN1PROD with PROPOSALS2
66114 Federal Register / Vol. 78, No. 213 / Monday, November 4, 2013 / Proposed Rules 

4This metric comes from the Benzene NESHAP. 

See 54 FR 38046. 

5U.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). 

6A census block is the smallest geographic area 

for which census statistics are tabulated. 

level that could be emitted by facilities 

without violating the MACT standards. 

We discussed the use of both MACTallowable 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 

MACT-allowable 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. (54 FR 

38044, September 14, 1989.) 

For the FPUF production source 

category, we determined that actual 

emissions are a reasonable estimate of 

the MACT-allowable emissions for 

molded and rebond foam facilities. The 

MACT requirements for these facilities 

are HAP use prohibitions, and both the 

actual and the MACT-allowable 

emissions, while in compliance with 

these requirements, are therefore zero. 

For slabstock foam production 

facilities, we estimate that the level of 

diisocyanate actual emissions is a 

reasonable estimate of the MACTallowable diisocyanate emissions. The 

diisocyanate storage vessels and other 

equipment are subject to equipment 

standards and work practices. For 

equipment standards, sources subject to 

the standards are required to install 

specific equipment. In order to comply 

with this proposed rule, the equipment 

must be maintained properly and in 

good working condition. Therefore, we 

do not expect any difference between 

the actual emissions level and the level 

allowed by the MACT standards 

because the level of control typically 

does not vary for equipment standards. 

Similarly, we do not expect any 

difference between actual and MACTallowable emissions for emission 

sources subject to work practice 

requirements, provided that facilities 

are not conducting additional work 

practices proven to reduce emissions 

beyond those required in this proposed 

rule. We are not aware of any such 

situations at facilities in this source 

category. Therefore, for facilities 

complying with the equipment and 

work practice standards, we believe that 

the actual diisocyanate emission levels 

are a reasonable estimation of the levels 

allowed by the standards. 

For HAP ABA emissions from 

slabstock facilities, we estimate that 

MACT-allowable emissions are higher 

than actual emissions. While we believe 

that all slabstock production facilities 

have discontinued use of HAP-based 

ABAs, and they are reporting zero 

emissions of HAP ABA, the MACT rule 

does not prohibit the use of HAP ABAs. 

Therefore, MACT-allowable HAP ABA 

emissions were attributed to each 

slabstock facility based on emissions 

information gathered during 

development of the MACT standards. 

We assigned appropriate emissions 

release parameters for each facility, and 

modeled using the same procedures and 

tools used for modeling actual 

emissions, to obtain facility-specific 

maximum risk values based on MACTallowable emissions. The docket for this 

rulemaking contains the following 

document which provides more 

information on the development of 

estimated MACT-allowable emissions: 

MACT-Allowable Emissions for the 

Flexible Polyurethane Foam Production 

Source Category. 

3. How did we conduct dispersion 

modeling, determine inhalation 

exposure 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,4 and (3) estimating individual 

and population-level inhalation risks 

using the exposure estimates and 

quantitative dose-response information. 

The air dispersion model used by the 

HEM–3 model (AERMOD) is one of the 

EPA’s preferred models for assessing 

pollutant concentrations from industrial 

facilities.5 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 824 

meteorological stations, selected to 

provide coverage of the United States 

and Puerto Rico. A second library of 

United States Census Bureau census 

block 6 internal point locations and 

populations provides the basis of 

human exposure calculations (U.S. 

Census, 2010). In addition, for each 

census block, the census library 

includes the elevation and controlling 

hill height, which are also used in 

dispersion calculations. A third library 

of pollutant unit risk factors and other 

health benchmarks is used to estimate 

health risks. These risk factors and 

health benchmarks are the latest values 

recommended by the EPA for HAP and 

other toxic air pollutants. These values 

are available at: 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), which is an upper 

bound estimate of an individual’s 

probability of contracting cancer over a 

lifetime of exposure to a concentration 

of 1 microgram of the pollutant 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 EPA 

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 doseVerDate Mar<15>2010 17:36 Nov 01, 2013 Jkt 232001 PO 00000 Frm 00008 Fmt 4701 Sfmt 4702 E:\FR\FM\04NOP2.SGM 04NOP2

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7These 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 Science Advisory Board 

(SAB) in their 2002 peer review of EPA’s National 

Air Toxics Assessment (NATA) titled, 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. 

8National Academy of Sciences (NAS), 2001. 

Standing Operating Procedures for Developing 

Acute Exposure Levels for Hazardous Chemicals, 

page 2. 

response 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 7) 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) 

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 either 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,’’ or, in cases where an 

RfC from the EPA’s IRIS database is not 

available, a value from the following 

prioritized sources: (1) The Agency for 

Toxic Substances and Disease Registry 

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 (mg/kg-day) for oral 

exposures), at or below which no 

adverse health effects are anticipated for 

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

noted above, a scientifically credible 

dose-response value that has been 

developed in a manner consistent with 

the EPA guidelines and has undergone 

a peer review process similar to that 

used by the EPA, in place of or in 

concert with other values. 

The EPA also evaluated screening 

estimates of acute exposures and risks 

for each of the HAP at the point of 

highest off-site exposure for each facility 

(i.e., not just the census block 

centroids), assuming that a person is 

located at this spot at a time when both 

the peak (hourly) emissions rate and 

worst-case dispersion conditions occur. 

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. 

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 

by 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),8 ‘‘the NRC’s 

previous name for acute exposure 

levels—community emergency exposure 

levels—was replaced by the term AEGL 

to reflect the broad application of these 

values to planning, response, and 

prevention in the community, the 

workplace, transportation, the military, 

and the remediation of Superfund 

sites.’’ Id. at 2. This document also 

states that AEGL values ‘‘represent 

threshold exposure limits for the general 

public and are applicable to emergency 

exposures ranging from 10 minutes to 

eight hours.’’ Id. at 2. The document 

lays out the purpose and objectives of 

AEGL by stating that ‘‘the primary 

purpose of the AEGL program and the 

National Advisory Committee for Acute 

Exposure Guideline Levels for 

Hazardous Substances is to develop 

guideline levels for once-in-a-lifetime, 

short-term exposures to airborne 

concentrations of acutely toxic, highpriority 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 


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66116 Federal Register / Vol. 78, No. 213 / Monday, November 4, 2013 / Proposed Rules 

9ERP Committee Procedures and Responsibilities. 

November 1, 2006. American Industrial Hygiene 

Association. 

10See http://www.tceq.state.tx.us/compliance/

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

source of these data. 

11The 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. 

12U.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 on-line at http:// 

cfpub.epa.gov/ncea/cfm/

recordisplay.cfm?deid=211003. 

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 ERP 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.’’ 9 Id. 

at 1. The ERPG–1 value is defined as 

‘‘the maximum airborne concentration 

below which it is believed that nearly 

all individuals could be exposed for up 

to 1 hour without experiencing other 

than mild transient adverse health 

effects or without perceiving a clearly 

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

Similarly, the ERPG–2 value is defined 

as ‘‘the maximum airborne 

concentration below which it is 

believed that nearly all individuals 

could be exposed for up to one hour 

without experiencing or developing 

irreversible or other serious health 

effects or symptoms which could impair 

an individual’s ability to take protective 

action.’’ Id. at 1. 

As can be seen from the definitions 

above, the AEGL and ERPG values 

include the similarly-defined severity 

levels 1 and 2. For many chemicals, a 

severity level 1 value AEGL or ERPG has 

not been developed because the types of 

effects for these chemicals are not 

consistent with the AEGL–1/ERPG–1 

definitions; in these instances, we 

compare higher severity level AEGL–2 

or ERPG–2 values to our modeled 

exposure levels to screen for potential 

acute concerns. When AEGL–1/ERPG–1 

values are available, they are used in 

our acute risk assessments. 

Acute REL values for 1-hour exposure 

durations are typically lower than their 

corresponding AEGL–1 and ERPG–1 

values. Even though their definitions are 

slightly different, AEGL–1 values are 

often the same as the corresponding 

ERPG–1 values, and AEGL–2 values are 

often equal to ERPG–2 values. 

Maximum HQ values from our acute 

screening risk assessments typically 

result when basing them on the acute 

REL value for a particular pollutant. In 

cases where our maximum acute HQ 

value exceeds 1, we also report the HQ 

value based on the next highest acute 

dose-response value (usually the AEGL– 

1 and/or the ERPG–1 value). 

To develop screening estimates of 

acute exposures in the absence of hourly 

emissions data, generally we first 

develop estimates of maximum hourly 

emissions rates by multiplying the 

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, but also reflecting a Texas 

study of short-term emissions 

variability, which showed that most 

peak emission events in a heavilyindustrialized four-county area (Harris, 

Galveston, Chambers and Brazoria 

Counties, Texas) were less than twice 

the annual average hourly emissions 

rate. The highest peak emissions event 

was 74 times the annual average hourly 

emissions rate, and the 99th percentile 

ratio of peak hourly emissions rate to 

the annual average hourly emissions 

rate was 9.10 Considering this analysis, 

to account for more than 99 percent of 

the peak hourly emissions, we apply a 

conservative screening multiplication 

factor of 10 to the average annual hourly 

emissions rate in our acute exposure 

screening assessments as our default 

approach. 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, 

however, there was no such information 

available and the default factor of 10 

was used in the acute screening process. 

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. 

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. However, we recognize that 

having this level of data is rare; hence, 

our use of 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,11 we 

generally examine a wider range of 

available acute health metrics (e.g., 

RELs, AEGLs) than we do for our 

chronic risk assessments. This is in 

response to the SAB’s acknowledgement 

that there are generally more data gaps 

and inconsistencies in acute reference 

values than there are in chronic 

reference values. In some cases, when 

Reference Value Arrays 12 for HAP have 

been developed, we consider additional 

acute values (i.e., occupational and 

international values) to provide a more 

complete risk characterization. 

4. How did we conduct the 

multipathway exposure and risk 

screening? 

The EPA conducted a screening 

analysis examining the potential for 

significant human health risks due to 

exposures via routes other than 

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

determined whether any sources in the 

source category emitted any hazardous 

air pollutants 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://

www.epa.gov/ttn/fera/risk_atra_

vol1.html). 

For the FPUF production source 

category, we did not identify emissions 

of any PB–HAP. Because we did not 

identify PB–HAP emissions, no further 


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13The secondary lead NAAQS is a reasonable 

measure of determining whether there is an adverse 

environmental effect since it was established 

considering ‘‘effects on soils, water, crops, 

vegetation, man-made materials, animals, wildlife, 

weather, visibility and climate, damage to and 

deterioration of property, and hazards to 

transportation, as well as effects on economic 

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

evaluation of multipathway risk was 

conducted for this source category. 

5. How did we assess risks considering 

emissions control options? 

In addition to assessing baseline 

inhalation risks and screening for 

potential multipathway risks, we also 

estimated risks considering the potential 

emissions reductions that would be 

achieved by the control options under 

consideration. In these cases, the 

expected emissions reductions were 

applied to the specific HAP and 

emissions points in the source category 

dataset to develop corresponding 

estimates of risk and incremental risk 

reductions. 

6. How did we conduct the 

environmental risk screening 

assessment? 

a. Adverse Environmental Effect 

The EPA developed a screening 

approach 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 

persistent bioaccumulative HAP (PB– 

HAP) and two acid gases. The five PB– 

HAP are cadmium, dioxins/furans, 

polycyclic organic matter (POM), 

mercury (both inorganic mercury and 

methyl mercury) and lead. 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 (based 

on data 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, we currently do not 

have the ability to calculate these 

concentrations using the TRIM.Fate 

model. Therefore, to evaluate the 

potential for environmental effects from 

lead, we compare the estimated chronic 

inhalation exposures from the source 

category emissions of lead with the level 

of the secondary National Ambient Air 

Quality Standard (NAAQS) for lead.13

We consider values below the level of 

the secondary lead NAAQS as 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 of the total acid gas HAP 

emitted by stationary sources. 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 to estimate the potential for an 

adverse environmental effect. 

For the FPUF production source 

category, the data do not show 

emissions of any of the seven HAP 

(cadmium, dioxins/furans, POM, 

mercury, HCL or HF) in the 

environmental risk screen. Because we 

did not identify emissions of these 

seven HAP from the source category, we 

did not conduct any further quantitative 

evaluation of environmental risk. 

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. 

7. How did we conduct facility-wide 

assessments? 

To put the source category risks in 

context, we typically examine the risks 

from the entire ‘‘facility,’’ where the 

facility includes all HAP-emitting 

operations within a contiguous area and 

under common control. In other words, 

we examine the HAP emissions not only 

from the source category emission 

points of interest, but also emissions of 

HAP from all other emissions sources at 

the facility for which we have data. The 

emissions data for estimating these 

‘‘facility-wide’’ risks were obtained from 

the 2005 NEI (available at http://

www.epa.gov/ttn/atw/nata2005). 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 

FPUF production source category risks 

were compared to the facility-wide risks 

to determine the portion of facility-wide 

risks that could be attributed to the 

FPUF production source category. We 

specifically examined the facilities 

associated with the highest estimates of 

risk and determined the percentage of 

that risk attributable to the FPUF 

production source category. The Draft 

Residual Risk Assessment for the 

Flexible Polyurethane Foam Production 

Source Category, available through the 

docket for this action, provides all the 

methodology and results of the facilitywide analyses, including all facilitywide risks and the percentage of FPUF 

production source category contribution 

to facility-wide risks. 

8. How did we consider uncertainties in 

risk assessment? 

In the Benzene NESHAP, we 

concluded that risk estimation 

uncertainty should be considered in our 

decision-making under the ample 

margin of safety framework. Uncertainty 

and the potential for bias are inherent in 

all risk assessments, including those 

performed for this proposal. Although 

uncertainty exists, we believe that our 


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14Short-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. 

15U.S. EPA. National-Scale Air Toxics 

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

2001; page 85.) 

approach, which used conservative 

tools and assumptions, ensures that our 

decisions are health-protective. A brief 

discussion of the uncertainties in the 

emissions dataset, dispersion modeling, 

inhalation exposure estimates and doseresponse relationships follows below. A 

more thorough discussion of these 

uncertainties is included in the Draft 

Residual Risk Assessment for the 

Flexible Polyurethane Foam Production 

Source Category, which is available in 

the docket for this action. 

a. Uncertainties in the Emissions 

Dataset 

Although the development of the RTR 

dataset involved quality assurance/

quality control processes, the accuracy 

of emissions values will vary depending 

on the source of the data, the degree to 

which data are incomplete or missing, 

the degree to which assumptions made 

to complete the datasets are accurate, 

errors in emissions estimates and other 

factors. The emission estimates 

considered in this analysis generally are 

annual totals for certain years, and they 

do not reflect short-term fluctuations 

during the course of a year or variations 

from year to year. The estimates of peak 

hourly emissions rates for the acute 

effects screening assessment were based 

on an emission adjustment factor 

applied to the average annual hourly 

emissions 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 estimated 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 over-estimate 

ambient levels (e.g., meteorology and 

receptor locations). On balance, 

considering the directional nature of the 

uncertainties commonly present in 

ambient concentrations estimated by 

dispersion models, the approach we 

apply in the RTR assessments should 

yield unbiased estimates of ambient 

HAP concentrations. 

c. Uncertainties in Inhalation Exposure 

The EPA did not include the effects 

of human mobility on exposures in the 

assessment. Specifically, short-term 

mobility and long-term mobility 

between census blocks in the modeling 

domain were not considered.14 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 receptors 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 emissions sources 

at facilities actually operate (i.e., more 

or less than 70 years) and the domestic 

growth or decline of the modeled 

industry (i.e., the increase or decrease in 

the number or size of 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 overstatement of 

25 to 30 percent of exposures.15

In addition to the uncertainties 

highlighted above, there are several 

factors specific to the acute exposure 

assessment that should be highlighted. 

The accuracy of an acute inhalation 

exposure assessment depends on the 

simultaneous occurrence of 

independent factors that may vary 

greatly, such as hourly emissions rates, 

meteorology and human activity 

patterns. In this assessment, we assume 

that individuals remain for 1 hour at the 

point of maximum ambient 

concentration as determined by the cooccurrence of peak emissions and worstcase meteorological conditions. These 

assumptions would tend to be worstcase actual exposures as it is unlikely 

that a person would be located at the 

point of maximum exposure during the 

time of worst-case impact. 

d. Uncertainties in Dose-Response 

Relationships 

There are uncertainties inherent in 

the development of the 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 


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

help_gloss.htm). 

17An 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. 

18According 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. 

19 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. 

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 

Draft Residual Risk Assessment for the 

Flexible Polyurethane Foam Production 

Source Category, 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).16 In some 

circumstances, the true risk could be as 

low as zero; however, in other 

circumstances the risk could be 

greater.17 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). 

RfCs and reference doses (RfDs) 

represent chronic exposure levels that 

provide an estimate (with uncertainty 

spanning perhaps an order of 

magnitude) of a continuous inhalation 

exposure or a daily oral exposure, 

respectively, to the human population 

(including sensitive subgroups) that is 

likely to be without an appreciable risk 

of deleterious effects during a lifetime. 

To derive values that are intended to be 

‘‘without appreciable risk,’’ the 

methodology relies upon an uncertainty 

factor (UF) approach (U.S. EPA, 1993, 

1994) which considers uncertainty, 

variability and gaps in the available 

data. The UFs are applied to derive 

reference values that are intended to 

protect against appreciable risk of 

deleterious effects. The UFs are 

commonly default values,18 e.g., factors 

of 10 or 3, used in the absence of 

compound-specific data; where data are 

available, UFs may also be developed 

using compound-specific information. 

When data are limited, more 

assumptions are needed and more UFs 

are used. 

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 two-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.19


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20Although 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. 

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 Science 

Advisory Board reviews and other 

reviews, we are confident that the 

models used in the screen are 

appropriate and state-of-the-art for the 

multipathway risk assessments 

conducted in support of RTR. 

Input uncertainty is concerned with 

how accurately the models have been 

configured and parameterized for the 

assessment at hand. For Tier 1 of the 

multipathway screen, we configured the 

models to avoid underestimating 

exposure and risk 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 nationallyrepresentative data sets for the more 

influential parameters in the 

environmental model, including 

selection and spatial configuration of 

the area of interest, lake location and 

size, meteorology, surface water and soil 

characteristics and structure of the 

aquatic food web. We also assume an 

ingestion exposure scenario and values 

for human exposure factors that 

represent reasonable maximum 

exposures. 

In Tier 2 of the multipathway 

assessment, we refine the model inputs 

to account for meteorological patterns in 

the vicinity of the facility versus using 

upper-end national values and we 

identify the actual location of lakes near 

the facility rather than the default lake 

location that we apply in Tier 1. By 

refining the screening approach in Tier 

2 to account for local geographical and 

meteorological data, we decrease the 

likelihood that concentrations in 

environmental media are overestimated, 

thereby increasing the usefulness of the 

screen. The assumptions and the 

associated uncertainties regarding the 

selected ingestion exposure scenario are 

the same for Tier 1 and Tier 2. 

For both Tiers 1 and 2 of the 

multipathway assessment, our approach 

to addressing model input uncertainty is 

generally cautious. We choose model 

inputs from the upper end of the range 

of possible values for the influential 

parameters used in the models, and we 

assume that the exposed individual 

exhibits ingestion behavior that would 

lead to a high total exposure. This 

approach reduces the likelihood of not 

identifying high risks for adverse 

impacts. 

Despite the uncertainties, when 

individual pollutants or facilities do 

screen out, we are confident that the 

potential for adverse multipathway 

impacts on human health is very low. 

On the other hand, when individual 

pollutants or facilities do not screen out, 

it does not mean that multipathway 

impacts are significant, only that we 

cannot rule out that possibility and that 

a refined multipathway analysis for the 

site might be necessary to obtain a more 

accurate risk characterization for the 

source category. 

For further information on 

uncertainties and the Tier 1 and 2 

screening methods, refer to the risk 

document Appendix 5, ‘‘Technical 

Support Document for TRIM-Based 

Multipathway Tiered Screening 

Methodology for RTR.’’ 

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 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) 20 of approximately 

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

million].’’ 54 FR 38045. 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 

tighter emission standards if necessary 

to provide an ample margin of safety. 

After conducting the ample margin of 

safety analysis, we consider whether a 

more stringent standard is necessary to 

prevent, taking into consideration costs, 

energy, safety, and other relevant 

factors, an adverse environmental effect. 

After conducting the ample margin of 

safety analysis, we consider whether a 

more stringent standard is necessary to 

prevent, taking into consideration costs, 

energy, safety, and other relevant 

factors, an adverse environmental effect. 

In past residual risk actions, the EPA 

considered a number of human health 

risk metrics associated with emissions 

from the categories under review, 

including the MIR, the number of 

persons in various risk ranges, cancer 

incidence, the maximum non-cancer HI 

and the maximum acute non-cancer 

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

2007; 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 

Federal Register notice. 

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. 

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 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. 


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21EPA’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 

titled, EPA’s Actions in Response to the Key 

Recommendations of the SAB Review of RTR Risk 

Assessment Methodologies. 

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.’ 

54 FR 38057. Thus, the level of the MIR 

is only one factor to be weighed in 

determining acceptability of risks. The 

Benzene NESHAP explained that ‘‘an 

MIR of approximately one in 10 

thousand should ordinarily be the upper 

end of the range of acceptability. As 

risks increase above this benchmark, 

they become presumptively less 

acceptable under CAA section 112, and 

would be weighed with the other health 

risk measures and information in 

making an overall judgment on 

acceptability. Or, the Agency may find, 

in a particular case, that a risk that 

includes MIR less than the 

presumptively acceptable level is 

unacceptable in the light of other health 

risk factors.’’ Id. at 38045. Similarly, 

with regard to the ample margin of 

safety analysis, the EPA stated in the 

Benzene NESHAP that: ‘‘EPA believes 

the relative weight of the many factors 

that can be considered in selecting an 

ample margin of safety can only be 

determined for each specific source 

category. This occurs mainly because 

technological and economic factors 

(along with the health-related factors) 

vary from source category to source 

category.’’ Id. at 38061. We also 

consider the uncertainties associated 

with the various risk analyses, as 

discussed earlier in this preamble, in 

our determinations of acceptability and 

ample margin of safety. 

The EPA notes that it has not 

considered certain health information to 

date in making residual risk 

determinations. At this time, we do not 

attempt to quantify those HAP risks that 

may be associated with emissions from 

other facilities that do not include the 

source categories in question, mobile 

source emissions, natural source 

emissions, persistent environmental 

pollution or atmospheric transformation 

in the vicinity of the sources in these 

categories. 

The agency understands the potential 

importance of considering an 

individual’s total exposure to HAP in 

addition to considering exposure to 

HAP emissions from the source category 

and facility. We recognize that such 

consideration may be particularly 

important when assessing non-cancer 

risks, where pollutant-specific exposure 

health reference levels (e.g., RfCs) are 

based on the assumption that thresholds 

exist for adverse health effects. For 

example, the agency recognizes that, 

although exposures attributable to 

emissions from a source category or 

facility alone may not indicate the 

potential for increased risk of adverse 

non-cancer health effects in a 

population, the exposures resulting 

from emissions from the facility in 

combination with emissions from all of 

the other sources (e.g., other facilities) to 

which an individual is exposed may be 

sufficient to result in increased risk of 

adverse non-cancer health effects. In 

May 2010, the SAB advised the EPA 

‘‘that RTR assessments will be most 

useful to decision makers and 

communities if results are presented in 

the broader context of aggregate and 

cumulative risks, including background 

concentrations and contributions from 

other sources in the area.’’ 21

In response to the SAB 

recommendations, the EPA is 

incorporating cumulative risk analyses 

into its RTR risk assessments. 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 overlapping 

sources in the same category; 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 non-cancer 

hazard indices from all non-carcinogens 

affecting the same target organ system. 

Although we are interested in placing 

source category and facility-wide HAP 

risks in the context of total HAP risks 

from all sources combined in the 

vicinity of each source, we are 

concerned about the uncertainties of 

doing so. Because of the contribution to 

total HAP risk from emissions 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 FPUF Production 

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 emissions 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 FPUF Production 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 emissions 


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sources in the FPUF production 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. 

D. What other analyses and reviews 

were conducted in support of this 

proposal and how did we conduct those 

analyses and reviews? 

In addition to the analyses described 

above, we reviewed the FPUF 

Production MACT standards to 

determine whether we should make 

additional amendments. From this 

review we have identified one 

additional revision. We are proposing 

revisions to the startup, shutdown and 

malfunction (SSM) provisions of the 

MACT rule in order to ensure that they 

are consistent with the court decision in 

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

Cir. 2008), which vacated two 

provisions that exempted sources from 

the requirement to comply with 

otherwise applicable section 112(d) 

emission standards during periods of 

SSM. Our analyses and proposed 

changes related to these issues are 

presented in section IV.D of this 

preamble. 

IV. Analytical Results and Proposed 

Decisions 

This section of the preamble provides 

the results of our RTR reviews of the 

FPUF Production MACT standards and 

our proposed revisions to the FPUF 

Production MACT standards regarding 

the startup, shutdown and malfunction 

provisions. 

A. What are the results of the risk 

assessment and analyses? 

As described above, for the FPUF 

production source category, we 

conducted an inhalation risk assessment 

for all HAP emitted, a multipathway 

screening analysis for PB–HAP emitted 

and an environmental HAP screening 

analysis. We also performed a facilitywide risk assessment for the facilities in 

the source category. Results of the risk 

assessment are presented briefly below 

and in more detail in the residual risk 

document: Draft Residual Risk 

Assessment for the Flexible 

Polyurethane Foam Production Source 

Category, which is available in the 

docket for this rulemaking. 

1. FPUF Production Source Category 

Inhalation Risk Assessment Results 

Table 2 of this preamble provides a 

summary of the results of the inhalation 

risk assessment for the source category. 

TABLE 2—FLEXIBLE POLYURETHANE FOAM PRODUCTION INHALATION RISK ASSESSMENT RESULTS

Number of facilities 1

Maximum individual 

cancer risk 

(in 1 million) 2

Estimated population at 

increased risk of cancer ≥ 1-in-1 million 

Estimated annual cancer 

incidence 

(cases per year) 

Maximum chronic noncancer TOSHI 3Maximum screening acute 

non-cancer HQ 4

Based on 

actual 

emissions 

level 2

Based on 

allowable 

emissions 

level 

Based on 

actual 

emissions 

level 2

Based on 

allowable 

emissions 

level 

Based on 

actual 

emissions 

level 2

Based on 

allowable 

emissions 

level 

Based on 

actual 

emissions 

level 

Based on 

allowable 

emissions 

level 

Based on actual emissions 

level 

Based on allowable emissions level 

13 ............................... 0.7 5 0 700 0.00004 0.0004 0.9 0.9 HQERPG–1 =

0.9 

HQREL = 4 

HQERPG–1=0.9 

1 Number of facilities evaluated in the risk analysis. 

2 Maximum individual excess lifetime cancer risk due to HAP emissions from the source category. 

3 Maximum TOSHI. The target organ with the highest TOSHI for the FPUF production source category is the respiratory system. 

4The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. HQ values shown 

use the lowest available acute threshold value, which in most cases is the REL. When HQ values exceed 1, we also show HQ values using the next lowest available 

acute dose-response value. See section III.A.3 of this preamble for explanation of acute dose-response values. 

The results of the inhalation risk 

modeling using actual emissions level 

data, as shown in Table 2, indicate that 

the maximum lifetime individual cancer 

risk could be up to 0.7-in-1 million, the 

maximum chronic non-cancer TOSHI 

value could be up to 0.9, and the 

maximum off-site acute HQ value could 

be up to 0.9. The total estimated 

national cancer incidence from these 

facilities based on actual emission levels 

is 0.00004 excess cancer cases per year 

or one case in every 25,000 years. 

As discussed in section III.A.2, we 

also determined that MACT-allowable 

HAP ABA emissions levels at slabstock 

production facilities are greater than 

actual HAP ABA emissions, while 

allowable emissions from all other 

processes are equal to actual emissions. 

The inhalation risk modeling using 

MACT-allowable HAP ABA emissions 

and the actual emissions for the other 

processes at slabstock production 

facilities, indicate that the maximum 

lifetime individual cancer risk could be 

up to 5-in-1 million, the maximum 

chronic non-cancer TOSHI value could 

be up to 0.9, and the maximum off-site 

acute HQ value could be up to 4, based 

on the REL value for methylene 

chloride. The total estimated national 

cancer incidence from these facilities 

based on the MACT-allowable emission 

levels is 0.0004 excess cancer cases per 

year or one case in every 2,500 years. 

For more detail about the MACTallowable emissions levels, see the 

memorandum, MACT-Allowable 

Emissions for the Flexible Polyurethane 

Foam Production Source Category, in 

the docket for this rulemaking. 

2. Acute Risk Results 

Table 2 shows the acute risk results 

for the FPUF production source 

category. The screening analysis for 

worst-case acute impacts was based on 

a conservative default emissions 

multiplier of 10 to estimate the peak 

hourly emission rates from the average 

rates. Refer to Appendix 6 of the draft 

residual risk document in the docket for 

the detailed acute risk results. 

3. Multipathway Risk Screening Results 

There are no PB-HAP emitted by 

facilities in this category. Therefore, we 

do not expect there is a potential for 

human health multipathway risks as a 

result of emissions of these HAP. 

4. Ecological Risk Screening Results 

The emissions data for the FPUF 

source category indicate that sources 

within this source category do not emit 

any of the seven pollutants that we 

identified as ‘‘environmental HAP,’’ as 

discussed earlier in this preamble. 

Based on the processes and materials 

used in the source category, we do not 

expect any of the seven environmental 

HAP to be emitted. Also, we are 

unaware of any adverse environmental 

effect caused by emissions of HAP that 

are emitted by this source category. 

Therefore, we do not expect an adverse 

environmental effect as a result of HAP 

emissions from this source category. 


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5. Facility-Wide Inhalation Risk 

Assessment Results 

Table 3 displays the results of the 

facility-wide risk assessment. This 

assessment is based on actual emission 

levels. For detailed facility-specific 

results, see Appendix 6 of the Draft 

Residual Risk Assessment for the 

Flexible Polyurethane Foam Production 

Source Category in the docket for this 

rulemaking. 

TABLE 3—FPUF PRODUCTION FACILITY-WIDE RISK ASSESSMENT RESULTS

Number of facilities analyzed .......................................................................................................................................................................... 13 

Cancer Risk: 

Estimated maximum facility-wide individual cancer risk (in 1 million) ..................................................................................................... 20 

Number of facilities with estimated facility-wide individual cancer risk of 100-in-1 million or more ........................................................ 0 

Number of facilities at which the FPUF production source category contributes 50 percent or more to the facility-wide individual 

cancer risks of 100-in-1 million or more ............................................................................................................................................... 0 

Number of facilities with estimated facility-wide individual cancer risk of 1-in-1 million or more ............................................................ 3 

Number of facilities at which the FPUF production source category contributes 50 percent or more to the facility-wide individual 

cancer risk of 1-in-1 million or more ..................................................................................................................................................... 0 

Chronic Non-cancer Risk: 

Maximum facility-wide chronic non-cancer TOSHI .................................................................................................................................. 0 .9 

Number of facilities with facility-wide maximum non-cancer TOSHI greater than 1 ............................................................................... 0 

Number of facilities at which the FPUF production source category contributes 50 percent or more to the facility-wide maximum 

non-cancer TOSHI of 1 or more ........................................................................................................................................................... 0 

The facility-wide MIR and TOSHI are 

based on actual emissions from all 

emissions sources at the identified 

facilities. The results indicate that 3 

facilities have a facility-wide cancer 

MIR greater than or equal to 1-in-1 

million. The maximum facility-wide 

MIR is 20-in-1 million, with emission 

points from the FPUF production source 

category contributing less than 10 

percent of the maximum facility-wide 

risk. The maximum facility-wide TOSHI 

is 0.9, with the FPUF production source 

category contributing 100 percent to the 

facility-wide TOSHI. 

6. What demographic groups might 

benefit from this regulation? 

To determine whether or not to 

conduct a demographics analysis, we 

look at a combination of factors 

including the MIR, non-cancer TOSHI, 

population around the facilities in the 

source category and other relevant 

factors. For the FPUF production source 

category, our analyses show that actual 

emissions result in no individuals being 

exposed to cancer risk greater than 1-in1 million or a non-cancer TOSHI greater 

than 1. Therefore, we did not conduct 

an assessment of risks to individual 

demographic groups for this 

rulemaking. However, we did conduct a 

proximity analysis, which identifies any 

overrepresentation of minority, low 

income or indigenous populations near 

facilities in the source category. The 

results of this analysis are presented in 

the section of this preamble titled, 

‘‘Executive Order 12898: Federal 

Actions to Address Environmental 

Justice in Minority Populations and 

Low-Income Populations.’’ 

B. What are our proposed decisions 

regarding risk acceptability, ample 

margin of safety and adverse 

environmental effects? 

1. Risk Acceptability 

As noted in section III.C of this 

preamble, we weigh all health risk 

factors in our risk acceptability 

determination, including the cancer 

MIR; the number of persons in various 

cancer and non-cancer risk ranges; 

cancer incidence; the maximum noncancer TOSHI; the maximum acute noncancer HQ; the extent of non-cancer 

risks; the potential for adverse 

environmental effects; the distribution 

of cancer and non-cancer risks in the 

exposed population; and risk estimation 

uncertainties (54 FR 38044, September 

14, 1989). 

For the FPUF production source 

category, the risk analysis indicates that 

the cancer risks to the individual most 

exposed could be up to 0.7-in-1 million 

due to actual emissions and 5-in-1 

million based on MACT-allowable 

emissions. These risks are considerably 

less than 100-in-1 million, which is the 

presumptive upper limit of acceptable 

risk. The risk analysis also shows very 

low cancer incidence (0.00004 cases per 

year), as well as no potential for adverse 

chronic or multi-pathway health effects. 

In addition, the risk assessment 

indicates no significant potential for 

multi-pathway health effects or adverse 

environmental effects. The acute noncancer risks based on actual emissions 

are all below an HQ of 1. Therefore, we 

find there is little potential concern of 

acute non-cancer health impacts from 

actual emissions. For acute non-cancer 

risks based on allowable emissions, 

there was an HQ of 4 based on the REL 

for methylene chloride. Since the acute 

modeling scenario is worst-case because 

of its confluence of peak emission rates 

and worst-case dispersion conditions, 

and since the HQ estimates for 

methylene chloride based on the AEGL– 

1 and ERPG–1 values for this facility are 

below 1, we are proposing to find that 

acute non-cancer health impacts of 

concern are unlikely. 

Considering all of the health risk 

information and factors discussed 

above, including the uncertainties 

discussed in section III.A.8 of this 

preamble, we propose that the risks 

from the FPUF production source 

category are acceptable. 

2. Ample Margin of Safety Analysis and 

Proposed Controls 

Although we are proposing that the 

risks from the FPUF production source 

category are acceptable, risk estimates 

for 700 individuals in the exposed 

population are above 1-in-1 million at 

the MACT-allowable emissions levels. 

Consequently, we further considered 

whether the FPUF Production MACT 

standards provide an ample margin of 

safety to protect public health at the 

MACT-allowable emissions levels. In 

this ample margin of safety analysis, we 

investigated available emissions control 

options that might reduce the risk 

associated with MACT-allowable 

emissions from the source category. We 

considered this information along with 

all of the health risks and other health 

information considered in our 

determination of risk acceptability. 

For HAP used as an ABA at slabstock 

foam production facilities, we 

considered prohibiting facilities from 

using any HAP or HAP-based product as 

an ABA, as an option to reduce risks 

from this source category. Emissions of 

HAP ABA were shown to contribute 


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66124 Federal Register / Vol. 78, No. 213 / Monday, November 4, 2013 / Proposed Rules 

22Hazardous Air Pollutant Emissions from the 

Production of Flexible Polyurethane Foam. Basis 

and Purpose Document for Proposed Standards.’’ 

Page 6–9. U.S. EPA Office of Air Quality Planning 

and Standards. September 1996. 

nearly 100 percent to the maximum 

individual cancer risks at the MACTallowable emissions level for this source 

category. This control option would 

require facilities to use ABAs that do 

not contain HAP. We estimate the HAP 

emissions reduction resulting from this 

control option would be approximately 

735 tpy from the baseline MACTallowable emissions level. We estimate 

there would be no costs associated with 

implementation of this option, as all 

facilities in the source category are 

reporting that they do not have HAP 

ABA emissions from the foam 

production line, and industry 

representatives have confirmed that all 

sources have already discontinued use 

of a HAP or HAP-based product as an 

ABA. Furthermore, there are no 

additional costs associated with the 

recordkeeping and reporting 

requirements for compliance. With this 

control option, we estimate the 

maximum cancer risks based on 

allowable emissions would be reduced 

from 5-in-1 million to less than 1-in-1 

million, the annual cancer incidence 

would be reduced from 0.0004 to 

0.00004, the acute HQ would be 

reduced from 4 to less than 1 and the 

non-cancer TOSHI would remain 

unchanged. We believe this HAP ABA 

prohibition is technically feasible for all 

slabstock FPUF production operations 

and is a cost-effective measure to 

achieve emissions and health risk 

reductions associated with the MACTallowable level of emissions. Therefore, 

based on this analysis, we are proposing 

under section 112(f)(2) of the CAA to 

prohibit the use of HAP or HAP-based 

products as ABAs. 

We are proposing that the existing 

MACT standards, as modified to include 

the HAP-based ABA prohibition 

described above, will provide an ample 

margin of safety to protect public health 

and prevent an adverse environmental 

effect. 

For diisocyanate storage vessels, as 

discussed in section IV.C.2. of this 

preamble, we identified one control 

option to further reduce HAP emissions 

from these storage vessels, which were 

shown to contribute approximately 1 

percent to the maximum individual 

cancer risks at the MACT-allowable 

emissions level for the source category. 

This control option would require 

sources to increase storage vessel HAP 

emissions control efficiencies to 98 

percent, using technologies such as 

regenerative thermal oxidizers (RTO) or 

recuperative thermal oxidizers (RCO). 

We estimate the resulting HAP 

reduction would be approximately 

0.0026 tpy from the baseline MACTallowable emissions level. The 

estimated cost effectiveness per ton of 

HAP emissions reduction would be 

$124 million and $269 million, based on 

using a RTO and RCO, respectively. The 

additional control requirement would 

not achieve a reduction in the maximum 

individual cancer risks or any of the 

other risk metrics due to emissions at 

the MACT-allowable level. Due to the 

minimal reductions in HAP emissions 

and risk, along with the substantial 

costs associated with this option, we are 

proposing that additional HAP 

emissions controls for FPUF production 

diisocyanate storage vessels are not 

necessary to provide an ample margin of 

safety. 

For equipment leaks at slabstock foam 

production facilities, as discussed in 

section IV.C.3. of this preamble, we 

identified several control options to 

further address risks from leaking 

components. We estimate that up to 3 

percent of the emissions and associated 

risk at the MACT-allowable levels could 

be attributed to equipment leaks.22 The 

control options identified include the 

use of ‘‘leakless’’ valves in diisocyanate 

service at slabstock facilities and 

implementation of an enhanced LDAR 

program for diisocyanate equipment 

leaks at slabstock facilities. These 

control options would require sources to 

use ‘‘leakless’’ valve technology or 

implement a LDAR program that would 

incorporate monitoring with EPA 

Method 21, specific leak definitions, 

and possibly a limit on the total number 

of non-repairable equipment allowed. 

We estimate the HAP reduction 

resulting from the ‘‘leakless’’ valve 

technology would be 1 tpy from the 

baseline MACT-allowable emissions 

level, with a cost effectiveness of 

$305,000/ton HAP reduction. The HAP 

emissions reduction resulting from an 

enhanced LDAR program would be 0.38 

tpy from the baseline MACT-allowable 

emissions level, with a cost 

effectiveness of approximately $74,000/ 

ton HAP reduction. The HAP emissions 

reduction resulting from the portion of 

an enhanced LDAR program that 

incorporates limits on the total number 

of non-repairable equipment allowed 

would be 0.08 tpy from the baseline 

MACT-allowable emissions level, with a 

cost effectiveness of approximately 

$234,000/ton HAP emissions reduction. 

None of these additional control 

requirements for diisocyanate 

equipment leaks would achieve a 

reduction in the maximum individual 

cancer risks or any of the other health 

risk metrics. Due to the minimal 

reductions in HAP emissions and risk, 

along with the substantial costs 

associated with these options, we are 

proposing that additional HAP 

emissions controls for FPUF production 

diisocyanate equipment leaks are not 

necessary to provide an ample margin of 

safety. 

3. Adverse Environmental Effects 

We did not identify emissions of the 

seven environmental HAP included in 

our environmental risk screening, and 

are unaware of any adverse 

environmental effects caused by other 

HAP emitted by this source category. 

Therefore, we do not expect there to be 

an adverse environmental effect as a 

result of HAP emissions from this 

source category, and we are proposing 

that it is not necessary to set a more 

stringent standard to prevent, taking 

into consideration costs, energy, safety, 

and other relevant factors, an adverse 

environmental effect. 

C. What are the results and proposed 

decisions based on our technology 

review? 

As described in section III.C of this 

preamble, our technology review 

focused on identifying developments in 

practices, processes and control 

technologies for the emission sources in 

the FPUF production source category. 

The following sections summarize our 

technology review results. More 

information concerning our technology 

review can be found in the 

memorandum titled, Technology Review 

and Cost Impacts for the Proposed 

Amendments to the Flexible 

Polyurethane Foam Production Source 

Category, which is available in the 

docket. 

1. Slabstock Foam Production Line 

The current MACT standards allow 

limited use of HAP-based ABAs at 

slabstock foam production facilities, 

while prohibiting the use of HAP-based 

products, with limited exceptions, for 

specific purposes at other types of FPUF 

production facilities (including 

equipment cleaning, mixhead flushing 

and facilitating mold release at molded 

and rebond foam facilities). The FPUF 

Production MACT standards also 

prohibit HAP and HAP-based products 

in equipment cleaners at slabstock foam 

facilities (except at facilities operating 

under the provisions for a source-wide 

emission limit for a single HAP ABA). 

Prohibiting the use of HAP-based ABAs 

and HAP-based equipment cleaners at 

slabstock foam production facilities has 

been identified as a development in 


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23Memorandum from Cindy Hancy, RTI to Jodi 

Howard, EPA, Analysis of Emission Reduction 

Techniques for Equipment Leaks, December 21, 

2011. (EPA–HQ–OAR–2002–0037–0180.) See 

Attachment 1. 

practices and/or processes that could 

reduce HAP emissions from the 

slabstock foam production line. 

At the time of promulgation of the 

FPUF MACT standards, the EPA 

believed that HAP ABAs were necessary 

for production of some grades of foam. 

Therefore, the FPUF Production MACT 

standards significantly limited the use 

of HAP ABAs by slabstock foam 

producers, but allowed their use in 

production of certain grades of foam. 

Available data from EPA databases, 

industry survey responses and contacts 

with state and local permitting agencies 

show that none of the 13 facilities 

currently identified as being subject to 

the FPUF Production MACT standards 

are using any HAP ABAs, or ABAs 

containing HAP (i.e., HAP-based ABAs). 

Further confirmation was received 

through discussions with the 

Polyurethane Foam Association (PFA), a 

trade association representing the 

slabstock polyurethane foam production 

industry. Details of the discussion with 

PFA are contained in Documentation of 

Communications with Industry and 

Regulatory Agency Contacts for the 

Flexible Polyurethane Foam Industry, 

which is available in the docket for this 

rulemaking. The discontinuation of 

HAP ABAs (or HAP-based ABAs) use by 

FPUF producers demonstrates that foam 

producers have improved their ability to 

produce their products using 

alternatives to HAP or HAP-based ABAs 

since the promulgation of the original 

FPUF Production NESHAP. 

No facilities subject to subpart III are 

currently using any HAP or HAP-based 

ABAs. Therefore, there will be no cost 

associated with codifying current 

industry practice prohibiting the use of 

HAP or HAP-based ABAs. There may be 

small cost savings at some facilities due 

to reduced monitoring and 

recordkeeping costs. Because there are 

no estimated costs, the industry is 

already complying with this HAP and 

HAP-based ABA prohibition in practice, 

and reductions in allowable emissions 

would be achieved, we are proposing 

that it is necessary, pursuant to CAA 

section 112(d)(6), to revise the MACT to 

prohibit the use of HAP and HAP-based 

ABAs at slabstock foam production 

facilities. As noted in section IV.B.2., we 

are concurrently proposing this HAP 

and HAP-based ABA prohibition under 

section 112(f)(2) of the CAA to provide 

an ample margin of safety to protect 

public health. Also, as noted in section 

II.B, we solicit comments regarding 

whether any facilities subject to subpart 

III currently use HAP or HAP-based 

ABAs. 

2. Diisocyanate Storage Vessels 

The FPUF Production MACT 

standards provide two compliance 

options for diisocyanate storage vessels: 

Equip the storage vessels (tanks) with a 

vapor return line from the storage vessel 

to the truck or rail car during unloading; 

or equip the storage vessel with a carbon 

adsorption system which routes 

displaced vapors through activated 

carbon. These control systems are 

estimated to have control efficiencies of 

95 percent. For the technology review, 

we identified two potential control 

options to capture and control 

emissions from storage tanks: 

Regenerative and recuperative thermal 

oxidizers. Both reportedly have control 

efficiencies of 98 percent, and known 

application to low concentration organic 

vapor gas streams. We estimate an 

additional emission reduction of 0.0026 

tpy would be associated with an 

increase from 95 percent estimated HAP 

control in the original FPUF MACT 

standards to 98 percent HAP control 

today. The estimated cost per ton of 

emissions reduction would be $124 

million and $270 million per ton of 

HAP for regenerative and recuperative 

thermal oxidizers, respectively. 

Based on the high costs and the 

minimal emissions reductions that 

would be achieved by these 

diisocyanate tank controls, we are 

proposing that it is not necessary to 

revise the MACT standards pursuant to 

CAA section 112(d)(6) to provide for a 

stricter level of control. 

3. Equipment Leaks 

For equipment leaks, we identified 

two developments in practices, process 

or control technologies: Use of 

‘‘leakless’’ valves in diisocyanate service 

at slabstock facilities and 

implementation of an enhanced 

equipment LDAR for diisocyanate 

equipment leaks at slabstock facilities. 

While there are requirements for LDAR 

in the original MACT standards, we 

further investigated LDAR for 

developments that have occurred since 

the rule was promulgated. The two 

developments in LDAR programs are a 

limit on the total number of nonrepairable equipment allowed and the 

inclusion of lower leak detection limits 

for valves and connectors than those 

considered previously for the MACT 

standards. 

a. ‘‘Leakless’’ Valves 

‘‘Leakless’’ valves that significantly 

reduce emissions are in place in some 

facilities outside the FPUF production 

source category, particularly oil 

refineries. We analyzed the costs 

associated with requiring this ‘‘leakless’’ 

valve technology for valves in 

diisocyanate service in the FPUF 

production source category using cost 

estimates developed for the synthetic 

organic chemical manufacturing 

industry. Nationwide annual costs were 

estimated to be $310,000/yr, with total 

capital investments of $2,260,000. 

Emission reductions were estimated to 

be 1 tpy, resulting in a cost effectiveness 

of $305,000/ton HAP reduction. 

Based on the high costs and the 

minimal emissions reductions that 

would be achieved using this 

technology, we are proposing that it is 

not necessary to revise the MACT 

standards pursuant to CAA section 

112(d)(6) to require the installation of 

‘‘leakless’’ valves. 

b. Implementation of Enhanced LDAR 

Programs 

The current MACT standards require 

an LDAR program that employs visual, 

audible or other methods for detecting 

leaks. This standard requires repair of 

leaks within 15 calendar days when 

leaks are detected by visual, audible or 

any other detection method for 

equipment, other than transfer pumps, 

in diisocyanate service. Leakless 

technology is required for transfer 

pumps. 

During the development of the MACT 

standards, another LDAR program, 

using Method 21, was identified as a 

beyond-the-floor method for controlling 

emissions from equipment leaks at 

slabstock foam facilities for equipment 

in diisocyanate service, but was not 

chosen as the level of the standard. At 

that time, the leak definition was set at 

a HAP concentration of 10,000 ppm or 

greater. Since the development of the 

MACT standards, analyses have been 

performed by the EPA regarding costs 

and emission reductions in the chemical 

and petroleum industries associated 

with lowering the level at which a HAP 

concentration is considered to be a leak 

for LDAR programs.23 We used these 

analyses in the CAA section 112(d)(6) 

technology review for the FPUF 

production source category to assess the 

effects of adding an enhanced LDAR 

program for metering pumps, valves, 

connectors and open-ended lines in 

diisocyanate service at slabstock foam 

production facilities. The LDAR 

program would incorporate monitoring, 

employing Method 21 of 40 CFR part 60, 

Appendix A, and lower leak definitions. 

The lower leak definitions considered 


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include two options identified in the 

EPA analysis of emissions reduction 

techniques for equipment leaks: 

1. Leak definition for metering pumps 

of 2,000 ppm; leak definition for valves, 

connectors and open-ended lines of 500 

ppm; 

2. Leak definition for valves of 100 

ppm; leak definition for metering 

pumps, connectors and open-ended 

lines of 500 ppm. 

We analyzed the costs associated with 

an LDAR programs with these two 

options for leak definitions for 

equipment in diisocyanate service. For 

both options, nationwide total annual 

costs were estimated to be around 

$28,200/yr, with total capital 

investments of approximately $32,400. 

Reduction of HAP emissions were 

estimated to be about 0.38 tpy, resulting 

in a cost effectiveness of approximately 

$74,000/ton HAP reduction. 

The current MACT standards allow 

leak repairs to be delayed under certain 

circumstances. Limits on the number of 

leaking components awaiting repair was 

also identified as a potential 

development in practice that could 

reduce diisocyanate emissions from 

equipment leaks. Both the California 

Bay Area Air Quality Management 

District (BAAQMD) and the South Coast 

Air Quality Management District have 

LDAR programs that limit the number of 

leaking equipment components awaiting 

repair. The BAAQMD rule also requires 

mass emission testing for leaking valves 

and requires valves with a high leak rate 

to be repaired within 7 days. We 

estimated the costs of requirements 

addressing equipment awaiting leak 

repair like those of the BAAQMD rule, 

irrespective of the other costs for an 

LDAR program. Nationwide annual 

costs were estimated to be $18,212/yr, 

with no capital investments required. 

Emission reductions were estimated to 

be 0.002 tpy, resulting in a cost 

effectiveness of $233,770 per ton of HAP 

reduction for equipment in diisocyanate 

service at slabstock facilities. 

Based on the high costs and the 

minimal emissions reduction that 

would be achieved with LDAR programs 

using Method 21 and either of the leak 

definition options, or with the 

restrictions on equipment awaiting 

repair, we are proposing that it is not 

necessary to revise the MACT standards 

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

require an enhanced LDAR program. 

However, we are adding a provision to 

the rule to clarify that delay of leak 

repairs for valves and connectors must 

be completed within 6 months of 

detection, as described in section 

IV.D.4. 

D. What other actions are we proposing? 

1. Startup, Shutdown and Malfunctions 

a. Background 

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. Sierra Club v. EPA, 551 

F.3d 1019 (D.C. Cir. 2008), cert. denied, 

130 S. Ct. 1735 (U.S. 2010). Specifically, 

the Court vacated the SSM exemption 

contained in 40 CFR 63.6(f)(1) and 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. 

We are proposing the elimination of 

the SSM exemption in this proposed 

rule. Therefore, this proposed rule has 

changed the indication of ‘‘Yes’’ to ‘‘No’’ 

in the General Provisions table (Table 2) 

of this rule for § 63.6(f), in which 

§ 63.6(f)(1) states, ‘‘The non-opacity 

emission standards set forth in this part 

shall apply at all times except during 

periods of startup, shutdown, and 

malfunction. . . .’’ Consistent with 

Sierra Club v. EPA, the EPA is 

proposing standards in this rule that 

apply at all times. We are also proposing 

several revisions to Table 2 

(Applicability of General Provisions), as 

is explained in more detail below. 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. Information on periods of 

startup and shutdown received from the 

facilities in the FPUF production 

industry indicate that emissions during 

these periods are the same as during 

normal operations. The primary means 

of compliance with the standards are 

through work practices and product 

substitutions, which eliminate the use 

of HAP, and are in place at all times. 

Therefore, separate standards for 

periods of startup and shutdown are not 

necessary and are not being proposed. 

Periods of startup, normal operations 

and shutdown are all predictable and 

routine aspects of a source’s operations. 

However, by contrast, malfunction is 

defined as a ‘‘sudden, infrequent, and 

not reasonably preventable failure of air 

pollution control and monitoring 

equipment, process equipment or a 

process to operate in a normal or usual 

manner * * *’’ (40 CFR 63.2). The EPA 

has determined that CAA section 112 

does not require that emissions that 

occur during periods of malfunction be 

factored into development of CAA 

section 112 standards. Under CAA 

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 CAA 

section 112 that directs the agency to 

consider malfunctions in determining 

the level ‘‘achieved’’ by the best 

performing or best controlled sources 

when setting emission standards. 

Moreover, while the EPA accounts for 

variability in setting emissions 

standards consistent with the CAA 

section 112 case law, nothing in that 

case law requires the agency to consider 

malfunctions as part of that analysis. 

Section 112 of the CAA uses the concept 

of ‘‘best controlled’’ and ‘‘best 

performing’’ unit in defining the level of 

stringency that CAA section 112 

performance standards must meet. 

Applying the concept of ‘‘best 

controlled’’ or ‘‘best performing’’ to a 

unit that is malfunctioning presents 

significant difficulties, as malfunctions 

are sudden and unexpected events. 

Further, accounting for malfunctions 

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 such, 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 


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general limit, individual permit, or even 

any upset provision can anticipate all 

upset situations. After a certain point, 

the transgression of regulatory limits 

caused by ‘uncontrollable acts of third 

parties,’ such as strikes, sabotage, 

operator intoxication or insanity, and a 

variety of other eventualities, must be a 

matter for the administrative exercise of 

case-by-case enforcement discretion, not 

for specification in advance by 

regulation.’’). In addition, the goal of a 

best controlled or best performing 

source is to operate in such a way as to 

avoid malfunctions of the source and 

accounting for malfunctions could lead 

to standards that are significantly less 

stringent than levels that are achieved 

by a well-performing nonmalfunctioning source. The EPA’s 

approach to malfunctions is consistent 

with CAA section 112 and is a 

reasonable interpretation of the statute. 

In the unlikely event that a source 

fails to comply with the applicable CAA 

section 112(d) 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(d) 

standard was, in fact, ‘‘sudden, 

infrequent, not reasonably preventable’’ 

and was not instead ‘‘caused in part by 

poor maintenance or careless 

operation.’’ 40 CFR 63.2 (definition of 

malfunction). 

Finally, the EPA recognizes that even 

equipment that is properly designed and 

maintained can sometimes fail and that 

such failure can sometimes cause a 

violation of the relevant emission 

standard. See, e.g., State 

Implementation Plans: Response to 

Petition for Rulemaking; Findings of 

Excess Emissions During Periods of 

Startup, Shutdown, and Malfunction; 

Proposed rule, 78 FR 12460 (Feb. 22, 

2013); State Implementation Plans: 

Policy Regarding Excessive Emissions 

During Malfunctions, Startup, and 

Shutdown (Sept. 20, 1999); Policy on 

Excess Emissions During Startup, 

Shutdown, Maintenance, and 

Malfunctions (Feb. 15, 1983). The EPA 

is, therefore, proposing to add an 

affirmative defense to civil penalties for 

violations of emission standards that are 

caused by malfunctions. (See 40 CFR 

63.1292 defining ‘‘affirmative defense’’ 

to mean, in the context of an 

enforcement proceeding, a response or 

defense put forward by a defendant, 

regarding which the defendant has the 

burden of proof, and the merits of which 

are independently and objectively 

evaluated in a judicial or administrative 

proceeding). We also are proposing 

other regulatory provisions to specify 

the elements that are necessary to 

establish this affirmative defense; the 

source must prove by a preponderance 

of the evidence that it has met all of the 

elements set forth in § 63.1290(e) (See 

40 CFR 22.24). The criteria are designed 

in part to ensure that the affirmative 

defense is available only where the 

event that causes a violation of the 

emission standard meets the narrow 

definition of malfunction in § 63.2 

(sudden, infrequent, not reasonably 

preventable and not caused by poor 

maintenance and or careless operation). 

For example, to successfully assert the 

affirmative defense, the source must 

prove by a preponderance of the 

evidence that the violation ‘‘[w]as 

caused by a sudden, infrequent, and 

unavoidable failure of air pollution 

control, process equipment, or a process 

to operate in a normal or usual manner. 

. . .’’ The criteria also are designed to 

ensure that steps are taken to correct the 

malfunction, to minimize emissions in 

accordance with section 63.1290(d) and 

to prevent future malfunctions. For 

example, the source must prove by a 

preponderance of the evidence that 

‘‘[r]epairs were made as expeditiously as 

possible when a violation occurred. . .’’ 

and that ‘‘[a]ll possible steps were taken 

to minimize the impact of the violation 

on ambient air quality, the environment 

and human health. . . .’’ In any judicial 

or administrative proceeding, the 

Administrator may challenge the 

assertion of the affirmative defense and, 

if the respondent has not met its burden 

of proving all of the requirements in the 

affirmative defense, appropriate 

penalties may be assessed in accordance 

with CAA section 113 (see also 40 CFR 

22.27). 

The EPA included an affirmative 

defense in the proposed rule in an 

attempt to balance 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 beyond the control of the 

source. The EPA must establish 

emission standards that ‘‘limit the 

quantity, rate, or concentration of 

emissions of air pollutants on a 

continuous basis.’’ 42 U.S.C. 7602(k) 

(defining ‘‘emission limitation’’ and 

‘‘emission standard’’). See generally 

Sierra Club v. EPA, 551 F.3d 1019, 1021 

(D.C. Cir. 2008) Thus, the EPA is 

required to ensure that emissions 

standards are continuous. The 

affirmative defense for malfunction 

events meets this requirement by 

ensuring that even where there is a 

malfunction, the emission standard is 

still enforceable through injunctive 

relief. The United States Court of 

Appeals for the Fifth Circuit recently 

upheld the EPA’s view that an 

affirmative defense provision is 

consistent with CAA section 113(e). 

Luminant Generation Co. LLC v. United 

States EPA, 714 F.3d 841 (5th Cir. Mar. 

25, 2013) (upholding the EPA’s approval 

of affirmative defense provisions in a 

CAA State Implementation Plan). While 

‘‘continuous’’ standards, on the one 

hand, are required, there is also case law 

indicating that in many situations it is 

appropriate for the EPA to account for 

the practical realities of technology. For 

example, in Essex Chemical v. 

Ruckelshaus, 486 F.2d 427, 433 (D.C. 

Cir. 1973), the DC Circuit acknowledged 

that in setting standards under CAA 

section 111 ‘‘variant provisions’’ such as 

provisions allowing for upsets during 

startup, shutdown and equipment 

malfunction ‘‘appear necessary to 

preserve the reasonableness of the 

standards as a whole and that the record 

does not support the ‘never to be 

exceeded’ standard currently in force.’’ 

See also, Portland Cement Association 

v. Ruckelshaus, 486 F.2d 375 (D.C. Cir. 

1973). Though intervening case law, 

such as Sierra Club v. EPA and the CAA 

1977 amendments, call into question the 

relevance of these cases today, they 

support the EPA’s view that a system 

that incorporates some level of 

flexibility is reasonable. The affirmative 

defense simply provides for a defense to 

civil penalties for violations that are 

proven to be beyond the control of the 

source. By incorporating an affirmative 

defense, the EPA has formalized its 

approach to malfunctions. In a Clean 

Water Act setting, the Ninth Circuit 

required this type of formalized 

approach when regulating ‘‘upsets 

beyond the control of the permit 

holder.’’ Marathon Oil Co. v. EPA, 564 

F.2d 1253, 1272–73 (9th Cir. 1977). See 

also, Mont. Sulphur & Chem. Co. v. 

EPA, 666 F.3d. 1174 (9th Cir. 2012) 

(rejecting industry argument that 

reliance on the affirmative defense was 

not adequate). But see, Weyerhaeuser 

Co. v. Costle, 590 F.2d 1011, 1057–58 

(D.C. Cir. 1978) (holding that an 

informal approach is adequate). The 

affirmative defense provisions give the 

EPA the flexibility to both ensure that 

its emission standards are ‘‘continuous’’ 

as required by 42 U.S.C. 7602(k), and 

account for unplanned upsets and thus 


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support the reasonableness of the 

standard as a whole. The EPA is 

proposing the affirmative defense 

applicable to malfunctions under the 

delegation of general regulatory 

authority set out in CAA section 

301(a)(1), 42 U.S.C. 7601(a)(1), in order 

to balance this tension between 

provisions of the CAA and the practical 

reality, as case law recognizes, that 

technology sometimes fails. See 

generally Citizens to Save Spencer 

County v. U.S. Environmental 

Protection Agency, 600 F.2d 844, 873 

(D.C. Cir. 1979) (using CAA section 

301(a) authority to harmonize 

inconsistent guidelines related to the 

implementation of federal 

preconstruction review requirements). 

b. Specific SSM-Related Proposed 

Changes 

To address the United States Court of 

Appeals for the District of Columbia 

Circuit vacatur of portions of the EPA’s 

CAA section 112 regulations governing 

the emissions of HAP during periods of 

SSM, we are revising and adding certain 

provisions to the FPUF Production rule. 

As described in detail below, we are 

revising the General Provisions (Table 2) 

to change several of the references 

related to requirements that apply 

during periods of SSM. We are also 

adding the following provisions to the 

FPUF Production rule: (1) The general 

duty to minimize emissions at all times, 

(2) the requirement for sources to 

comply with the emission limits in the 

rule at all times, and (3) malfunction 

recordkeeping and reporting 

requirements. 

i. § 63.1290(d)(4) General Duty 

We are proposing to revise the 

General Provisions table (Table 2) entry 

for § 63.6(e)(1)-(2) by adding rows 

specifically for § 63.6(e)(1)(i), 

63.6(e)(1)(ii) and 63.6(e)(1)(iii) and to 

include a ‘‘no’’ in the second column for 

the § 63.6(e)(1)(i) entry. 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 § 63.1290(d)(4) 

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 does not include that 

language from § 63.6(e)(1). 

We are also proposing to include a 

‘‘no’’ in the second column for the 

newly added § 63.6(e)(1)(ii) entry. 

Section 63.6(e)(1)(ii) imposes 

requirements that are not necessary with 

the elimination of the SSM exemption 

or are redundant of the general duty 

requirement being added at 

§ 63.1290(d)(4). 

ii. Compliance With Standards 

We are proposing to revise the 

General Provisions table (Table 2) entry 

for § 63.6(f) by adding a specific entry 

for § 63.6(f)(1) and including a ‘‘no’’ in 

the second column for this § 63.6(f)(1) 

entry. The current language of section 

63.6, paragraph (f)(1) exempts sources 

from non-opacity standards during 

periods of SSM. As discussed above, the 

court in Sierra Club vacated the 

exemptions contained in this provision 

and held that the CAA requires that 

some CAA section 112 standard apply 

continuously. Consistent with Sierra 

Club, the EPA is proposing to revise 

standards in this rule to apply at all 

times. 

iii. § 63.1307(h) Recordkeeping 

We are proposing to revise the 

General Provisions table (Table 2) entry 

for § 63.10(a)–(b) by adding rows 

specifically for § 63.10(a), 63.10(b)(1), 

63.10 (b)(2)(i), 63.10 (b)(2)(ii), 63.10 

(b)(2)(iii), 63.10 (b)(2)(iv)–(xi), 63.10 

(b)(2)(xii), 63.10 (b)(xiii), and 63.10 

(b)(2)(xiv) in order to specify changes 

we are making to the applicability of 

several of the § 63.10(b)(2) paragraphs. 

In the entry for § 63.10(b)(2)(i), we are 

including a ‘‘no’’ in the second column. 

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. 

In the entry for § 63.10(b)(2)(ii), we 

are including a ‘‘no’’ in the second 

column. Section 63.10(b)(2)(ii) describes 

the recordkeeping requirements during 

a malfunction. The EPA is proposing to 

add such requirements to 40 CFR 

63.1307(h). 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 § 63.1307(h) a 

requirement that sources keep records 

that include a list of the affected sources 

or equipment and actions taken to 

minimize emissions, an estimate of the 

volume of each regulated pollutant 

emitted over the standard for which the 

source failed to meet a standard, and a 

description of the method used to 

estimate the emissions. Examples of 

such methods would include productloss calculations, mass balance 

calculations, measurements when 

available, or engineering judgment 

based on known process parameters. 

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 including a ‘‘no’’ in the second 

column in the entry for § 63.10(b)(2)(iv) 

and 63.10(b)(2)(v). When applicable, the 

provisions require sources to record 

actions taken during SSM events when 

actions were inconsistent with their 

SSM plan. These requirements are not 

appropriate because SSM plans are not 

(and were not) required by this rule, and 

the General Provisions applicability 

table referenced these sections in error. 

iv. § 63.1306(f) Reporting 

We are proposing to revise the 

General Provisions table (Table 2) entry 

for § 63.10(d)(4)–(5) by adding a specific 

entry for § 63.10(d)(5) and including a 

‘‘no’’ in the second column for this 

§ 63.10(d)(5) entry. 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 63.1306(f). The replacement 

language differs from the General 

Provisions requirement in that it 

eliminates periodic SSM reports 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 semiannual report for slabstock affected 

sources and in the annual compliance 


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certification for molded and rebond 

affected sources, which are already 

required under this rule. We are 

proposing that the malfunction report 

must contain the number, date, time, 

duration, and the cause of such events 

(including unknown cause, if 

applicable), a list of the affected sources 

or equipment, an estimate of the volume 

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 product-loss calculations, mass 

balance calculations, measurements 

when available, or engineering 

judgment based on known process 

parameters. 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. 

The proposed rule eliminates the 

cross reference to section 63.10(d)(5)(i) 

that contains the description of the 

previously required SSM report format 

and submittal schedule from this 

section. These specifications are no 

longer necessary because the events will 

be reported in otherwise required 

reports with similar format and 

submittal requirements. 

We note that reporting a failure to 

meet an applicable standard could 

include malfunction events for which a 

source may choose to submit 

documentation to support an assertion 

of affirmative defense. If a source 

provides all the material required in 

section 63.1290(e) to support an 

affirmative defense, the source need not 

submit the same information two times 

in the same report. While assertion of an 

affirmative defense is not mandatory 

and occurs only if a source chooses to 

take advantage of the affirmative 

defense, the affirmative defense also 

requires additional reporting that goes 

beyond these routine requirements 

related to a failure to meet an applicable 

standard for a reason other than a 

malfunction. 

The proposed rule also eliminates the 

cross-reference to section 63.10(d)(5)(ii). 

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. These requirements are not 

appropriate because SSM plans are not 

required by this rule, and the General 

Provisions applicability table referenced 

this section in error. 

2. Electronic Reporting of Performance 

Test Data 

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 

FPUF production facilities submit 

electronic copies of required 

performance test 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 EPA’s portal for 

submittal of electronic data. The EPAprovided 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 

EPA’s public database called WebFIRE. 

All stakeholders will 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 and instructions for use of 

the ERT can be found at http:// 

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

and CEDRI can be accessed through the 

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

description of the WebFIRE database is 

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

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

The proposal to submit performance 

test data electronically to the EPA 

applies only to those performance tests 

conducted using test methods that are 

supported by the ERT. The ERT 

supports 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 will 

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 

time spent on data backfilling if a source 

failed 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 benefits 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. 

Since the EPA will already have 

performance test data in hand, another 

benefit to industry is that fewer or less 

substantial data collection requests in 

conjunction with prospective required 

residual risk assessments or technology 

reviews will be needed. This would 

result in a decrease in 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. For example, the 

ERT would allow for an electronic 

review process, rather than a manual 

data assessment, therefore, making 

review and evaluation of the source 

provided data and calculations easier 

and more efficient. In addition, the 

public stands to 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. 

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 proposed rule. The ERT 

clearly states what testing information 

would be required by the test method 

and has the ability to house additional 

data elements that might be required by 

a delegated authority. 

In addition the EPA must have 

performance test data to conduct 

effective reviews of CAA sections 111, 

112 and 129 standards, as well as for 

many other purposes including 

compliance determinations, emission 

factor development and annual 

emission rate determinations. In 

conducting these required reviews, the 

EPA has found it ineffective and time 

consuming, not only for us, but also for 

regulatory agencies and source owners 

and operators, to locate, collect and 

submit performance test data. In recent 


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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. 

A common complaint heard from 

industry and regulators is that emission 

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 emission factors, 

when updated, represent the most 

current range of operational practices. 

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. 

Finally, the general public would also 

benefit from electronic reporting of 

emissions data because the data would 

be available for viewing sooner and 

would be easier for the public to access. 

The EPA Web site that stores the 

submitted electronic data will be easily 

accessible to the public and will provide 

a user-friendly interface that any 

stakeholder could access. 

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 

emission inventories and air quality 

regulations. Electronic databases will 

also benefit the general public by 

improving accessibility to emissions 

data in an efficient and timely manner. 

3. Clarification to Diisocyanate Storage 

Vessels Leak Detection Methods 

The EPA is proposing to clarify the 

leak detection methods that may be 

used for diisocyanate storage vessels at 

slabstock foam production facilities 

during unloading events. The current 

requirements allow the vapor return line 

to be inspected for leaks during 

unloading events using visual, audible 

or any other detection method. Today, 

the EPA is proposing to clarify, that 

‘‘any other detection method’’ must be 

an instrumental detection method. 

4. Clarification to Diisocyanate 

Equipment Leak Delay of Repair 

Requirements for Valves and Connectors 

The FPUF Production MACT 

standards generally require equipment 

leaks to be repaired within 15 days. 

However, there are also provisions that 

allow for a delay of repair. A delay of 

repair for pumps is allowed if repair 

requires replacing the existing seal 

design with a sealless pump, and the 

repair is completed as soon as 

practicable, but not later than 6 months 

after the leak is detected. For valves and 

connectors, a delay of repair is allowed 

if the owner or operator determines that 

diisocyanate emissions of purged 

material resulting from immediate 

repair are greater than the fugitive 

emissions likely to result from a delay 

of repair. However, for valves and 

connectors, the current provisions do 

not state how long such a delay may 

last. To be consistent with the 

requirements for pumps, we are 

proposing to clarify that, for valves and 

connectors, the repair must be 

completed as soon as practicable, but 

not later than 6 months after the leak 

was detected. 

E. What compliance dates are we 

proposing? 

We are proposing that FPUF 

production facilities comply with the 

new proposed requirements prohibiting 

the use of HAP ABAs in this action no 

later than 90 days after the effective date 

of the final rule. This time period will 

be sufficient because all FPUF 

production facilities have already 

discontinued use of HAP ABAs. 

We are proposing that facilities must 

comply with the SSM reporting and 

recordkeeping requirements and 

affirmative defense provisions, and 

requirements for electronic reporting on 

the effective date of the rule. We are 

proposing these compliance dates 

because the revised SSM requirements 

should be immediately implementable 

by the facilities upon the next 

occurrence of a malfunction, and the 

electronic reporting requirements 

should be immediately implementable 

by the facilities upon their next 

performance test. 

V. Summary of Cost, Environmental 

and Economic Impacts 

A. What are the affected sources? 

We anticipate that 13 FPUF 

production facilities currently operating 

in the United States will be affected by 

these proposed amendments. We also 

expect no new facilities to be 

constructed in the foreseeable future. 

For more information about expected 

new facilities, see the document titled, 

Documentation of Communications 

with Industry and Regulatory Agency 

Contacts for the Flexible Polyurethane 

Foam Industry, located in the docket for 

this action. 

B. What are the air quality impacts? 

The EPA estimates that the proposed 

amendments to the FPUF Production 

MACT standards will not result in any 

directly quantifiable reduction of HAP 

emissions. Emissions of HAP from 

FPUF production sources have 

significantly declined since 

promulgation of the FPUF Production 

MACT standards because HAP ABAs 

are no longer used by FPUF production 

facilities. However, as discussed in 

section III.A.2, the MACT standards 

currently allow sources to use HAP 

ABAs. We estimate that the MACTallowable emissions for the FPUF 

production source category are 735 tons 

of HAP ABAs. If the proposed revision 

prohibiting the use of HAP ABAs is 

finalized, the MACT-allowable 

emissions from ABA use would be zero. 

A detailed documentation of the 

analysis can be found in: MACTAllowable Emissions for the Flexible 

Polyurethane Foam Production Source 

Category, which is available in the 

docket for this rulemaking. 

C. What are the cost impacts? 

Under the proposed amendments, 

FPUF production facilities are not 

expected to incur any costs. However, 

there may be small cost savings at some 

facilities due to reduced monitoring and 

recordkeeping costs. The memorandum, 

Technology Review and Cost Impacts 

for the Proposed Amendments to the 

Flexible Polyurethane Foam Production 

Source Category, includes a complete 

description of the cost estimate methods 

used for the analyses related to the 

proposed HAP and HAP-based ABA 

prohibition and is available in the 

docket. 

D. What are the economic impacts? 

Because no costs or a small cost 

savings are expected as a result of the 

proposed amendments, there will not be 

any significant impacts on affected firms 

and their consumers as a result of this 

proposal. 

Because no small firms face 

significant control costs, there is no 

significant impact on small entities. 

Thus, this regulation is not expected to 

have a significant impact on a 

substantial number of small entities. 

E. What are the benefits? 

We do not anticipate any significant 

actual emission reductions of HAP as a 

result of these proposed amendments. 

However, if finalized, the proposed 

prohibition on HAP ABA use would 

eliminate the possibility that facilities 


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might begin to use HAP ABAs again. 

Under the existing rule, those possible 

emissions are estimated at 735 tons of 

HAP ABAs. If the prohibition is 

adopted, no emissions of HAP ABA 

would be allowed by the standard. 

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 on the RTR Web page 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 Number 

EPA–HQ–OAR–2012–0510 (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 page at: http://www.epa.gov/ttn/

atw/rrisk/rtrpg.html. 

VIII. Statutory and Executive Order 

Reviews 

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’’ under the terms of 

Executive Order 12866 (58 FR 51735, 

October 4, 1993) and is therefore not 

subject to review under Executive 

Orders 12866 and 13563 (76 FR 3821, 

January 21, 2011). 

B. Paperwork Reduction Act 

The information collection 

requirements in this proposed rule have 

been submitted for approval to OMB 

under the Paperwork Reduction Act, 44 

U.S.C. 3501, et seq. The Information 

Collection Request (ICR) document 

prepared by the EPA has been assigned 

EPA ICR number 1783.07. 

The information requirements are 

based on notification, recordkeeping, 

and reporting requirements in the 

NESHAP General Provisions (40 CFR 

part 63, subpart A), which are 

mandatory for all operators subject to 

national emissions standards. These 

recordkeeping and reporting 

requirements are specifically authorized 

by CAA section 114 (42 U.S.C. 7414). 

All information submitted to the EPA 

pursuant to the recordkeeping and 

reporting requirements for which a 

claim of confidentiality is made is 

safeguarded according to agency 

policies set forth in 40 CFR part 2, 

subpart B. 

For this proposed rule, the EPA is 

adding affirmative defense to the 

estimate of burden in the ICR. To 

provide the public with an estimate of 

the relative magnitude of the burden 

associated with an assertion of the 

affirmative defense position adopted by 

a source, the EPA has provided 

administrative adjustments to this ICR 

to show what the notification, 

recordkeeping and reporting 

requirements associated with the 

assertion of the affirmative defense 

might entail. The EPA’s estimate for the 

required notification, reports and 

records for any individual incident, 

including the root cause analysis, totals 

$2,188 for the FPUF production source 

category, and is based on the time and 

effort required of a source to review 

relevant data, interview plant 

employees, and document the events 

surrounding a malfunction that has 

caused an exceedance of an emissions 

limit. The estimate also includes time to 

produce and retain the record and 

reports for submission to the EPA. The 

EPA provides this illustrative estimate 

of this burden because these costs are 

only incurred if there has been a 

violation and a source chooses to take 

advantage of the affirmative defense. 

Given the variety of circumstances 

under which malfunctions could occur, 

as well as differences among sources’ 

operation and maintenance practices, 

we cannot reliably predict the severity 

and frequency of malfunction-related 

excess emissions events for a particular 

source. It is important to note that the 

EPA has no basis currently for 

estimating the number of malfunctions 

that would qualify for an affirmative 

defense. Current historical records 

would be an inappropriate basis, as 

source owners or operators previously 

operated their facilities in recognition 

that they were exempt from the 

requirement to comply with emissions 

standards during malfunctions. Of the 

number of excess emissions events 

reported by source operators, only a 

small number would be expected to 

result from a malfunction (based on the 

definition above), and only a subset of 

excess emissions caused by 

malfunctions would result in the source 

choosing to assert the affirmative 

defense. Thus, we believe the number of 

instances in which source operators 

might be expected to avail themselves of 

the affirmative defense will be 

extremely small. With respect to the 

FPUF production source category, we 

estimate the annual recordkeeping and 

reporting burden after the effective date 

of the proposed rule for affirmative 

defense to be 30 hours at a cost of 

$2,188. We expect to gather information 

on such events in the future and will 

revise this estimate as better information 

becomes available. 

We estimate approximately 13 

regulated entities are currently subject 

to 40 CFR part 63, subpart III, and will 

be subject to all proposed standards, a 

decrease of 119 regulated entities from 

our estimate for the previous ICR (EPA 

ICR Number 1783.05, OMB Control 

Number 2060–0357) for the FPUF 

production source category. The annual 

monitoring, reporting, and 

recordkeeping burden for this collection 

(averaged over the first 3 years after the 


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effective date of the standards) for 

subpart III (FPUF production), including 

today’s proposed amendments, is 

estimated to be $90,104 per year. This 

includes 1,030 labor hours per year at a 

total labor cost of $90,104 per year, and 

total non-labor capital and operation 

and maintenance costs of $0 per year. 

This represents a decrease of $760,000 

and 8,000 labor hours from the previous 

ICR, due primarily to the reduction in 

the estimated number of regulated 

entities. Our estimate of the burden for 

each regulated entity has increased by 

$485 and 11 labor hours from the 

previous ICR estimate. This increase in 

burden for each regulated entity is not 

due to the proposed amendments, but is 

due to a correction of an error in the 

total number of reports required per 

year for slabstock foam producers. This 

was previously estimated to be two 

semi-annual reports per year, but this 

estimate did not account for the annual 

compliance report. 

The total burden for the federal 

government (averaged over the first 3 

years after the effective date of the 

standard) is estimated to be 67 hours per 

year at a total labor cost of $3,607 per 

year. Burden is defined at 5 CFR 

1320.3(b). 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 number EPA–HQ–OAR–2012–0510. 

Submit any comments related to the ICR 

to the EPA and OMB. See the ADDRESSES

section at the beginning of this notice 

for where to submit comments to the 

EPA. Send comments to OMB at the 

Office of Information and Regulatory 

Affairs, Office of Management and 

Budget, 725 17th Street NW., 

Washington, DC 20503, Attention: Desk 

Office for EPA. Because OMB is 

required to make a decision concerning 

the ICR between 30 and 60 days after 

November 4, 2013, a comment to OMB 

is best assured of having its full effect 

if OMB receives it by December 4, 2013. 

The final rule will respond to any OMB 

or public comments on the information 

collection requirements contained in 

this proposal. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act 

generally requires an agency to prepare 

a regulatory flexibility analysis of any 

rule subject to notice and comment 

rulemaking requirements under the 

Administrative Procedure Act or any 

other statute unless the agency certifies 

that the rule will not have a significant 

economic impact on a substantial 

number of small entities. Small entities 

include small businesses, small 

organizations, and small governmental 

jurisdictions. 

For purposes of assessing the impacts 

of this proposed rule on small entities, 

small entity is defined as: (1) A small 

business as defined by the Small 

Business Administration’s (SBA) 

regulations at 13 CFR 121.201; (2) a 

small governmental jurisdiction that is a 

government of a city, county, town, 

school district or special district with a 

population of less than 50,000; and (3) 

a small organization that is any not-forprofit enterprise that is independently 

owned and operated and is not 

dominant in its field. 

After considering the economic 

impacts of today’s proposed rule on 

small entities, I certify that this action 

will not have a significant economic 

impact on a substantial number of small 

entities. The small entities directly 

regulated by this proposed rule are 

small businesses. We have determined 

that three facilities, or 23 percent of the 

13 affected facilities, are small entities. 

Total annualized costs for the proposed 

rule are estimated to be $0, and no small 

entities are projected to incur costs. 

Because HAP ABAs are no longer used 

by FPUF production facilities, there are 

no impacts on any entities subject to 

this rulemaking. 

We continue to be interested in the 

potential impacts of the proposed rule 

on small entities and welcome 

comments on issues related to such 

impacts. 

D. Unfunded Mandates Reform Act 

This action contains no federal 

mandate under the provisions of Title II 

of the Unfunded Mandates Reform Act 

of 1995 (UMRA), 2 U.S.C. 1531–1538 for 

state, local, or tribal governments or the 

private sector. This action imposes no 

enforceable duties on any state, local or 

tribal governments or the private sector. 

Therefore, this action is not subject to 

the requirements of sections 202 or 205 

of the UMRA. 

This action is also not subject to the 

requirements of section 203 of UMRA 

because it contains no regulatory 

requirements that might significantly or 

uniquely affect small governments 

because it contains no requirements that 

apply to such governments nor does it 

impose obligations upon them. 

E. Executive Order 13132: Federalism 

This proposed 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, as specified in 

Executive Order 13132. This action will 

not impose substantial direct 

compliance costs on state or local 

governments, nor will it preempt state 

law, and none of the facilities subject to 

this action are owned or operated by 

state governments. Thus, Executive 

Order 13132 does not apply to this 

action. 

In the spirit of Executive Order 13132, 

and consistent with the EPA policy to 

promote communications between the 

EPA and state and local governments, 

the EPA specifically solicits comment 

on this action from state and local 

officials. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does not have tribal 

implications, as specified in Executive 

Order 13175 (65 FR 67249, November 9, 

2000). There are no FPUF production 

facilities that are within 3 miles of tribal 

lands. Thus, Executive Order 13175 

does not apply to this action. 

The EPA specifically solicits 

additional comment on this proposed 

action from tribal officials. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

This action is not subject to Executive 

Order 13045 (62 FR 19885, April 23, 

1997) because it is not economically 

significant as defined in Executive 

Order 12866, and because the agency 

does not believe the environmental 

health risks or safety risks addressed by 

this action present a disproportionate 

risk to children. This proposed action’s 

health and risk assessments are 

contained in section IV of this preamble. 

The public is invited to submit 

comments or identify peer-reviewed 

studies and data that assess effects of 

early life exposure to HAP emitted by 

FPUF production facilities. 


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H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not a ‘‘significant 

energy action’’ as defined in Executive 

Order 13211 (66 FR 28355 (May 22, 

2001)), because it is not likely to have 

a significant adverse effect on the 

supply, distribution, or use of energy. 

We have concluded that this rule is not 

likely to have any adverse energy effects 

because the proposed requirements of 

this rule will not cause the additional 

use of energy by any facilities in the 

source category nor is there any 

expected impact on sources in the 

energy supply, distribution, or use 

sectors related to the proposed 

provisions of this rule. 

I. National Technology Transfer and 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (‘‘NTTAA’’), Public Law 

104–113 (15 U.S.C. 272 note), directs 

the EPA to use voluntary consensus 

standards (VCS) in its regulatory 

activities unless to do so would be 

inconsistent with applicable law or 

otherwise impractical. VCS are 

technical standards (e.g., materials 

specifications, test methods, sampling 

procedures, and business practices) that 

are developed or adopted by voluntary 

consensus standards bodies. NTTAA 

directs the EPA to provide Congress, 

through OMB, explanations when the 

agency decides not to use available and 

applicable VCS. 

The proposed rulemaking involves 

technical standards. Therefore, the 

agency conducted a search to identify 

potentially applicable voluntary 

consensus standards. However, we 

identified no such standards, and none 

were brought to our attention in 

comments. Therefore, the EPA has 

decided to use EPA Method 25A, 

‘‘Determination of Total Gaseous 

Organic Concentration Using a Flame 

Ionization Analyzer,’’ 40 CFR part 60, 

Appendix A, to measure organic 

compound concentrations. 

EPA welcomes comments on this 

aspect of the proposed rulemaking and, 

specifically, invites the public to 

identify potentially-applicable 

voluntary consensus standards and to 

explain why such standards should be 

used in this regulation. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

Executive Order 12898 (59 FR 7629, 

February 16, 1994) establishes federal 

executive policy on environmental 

justice. Its main provision directs 

federal agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies and activities on minority 

populations and low-income 

populations in the United States. 

The EPA has determined that this 

proposed rule will not have 

disproportionately high and adverse 

human health or environmental effects 

on minority or low-income populations, 

because it increases the level of 

environmental protection for all affected 

populations without having any 

disproportionately high and adverse 

human health or environmental effects 

on any population, including any 

minority or low-income population. 

To gain a better understanding of the 

source category and near source 

populations, the EPA conducted a 

proximity analysis on FPUF production 

facilities to identify any 

overrepresentation of minority, low 

income or indigenous populations. This 

analysis only gives some indication of 

the prevalence of sub-populations that 

may be exposed to air pollution from 

the sources; it does not identify the 

demographic characteristics of the most 

highly affected individuals or 

communities, nor does it quantify the 

level of risk faced by those individuals 

or communities. More information on 

the source category’s risk can be found 

in section IV of this preamble. 

The proximity analysis reveals that 

most demographic categories are below 

or within 20 percent of their 

corresponding national averages. The 

one exception is the African American 

population. The ratio of African 

Americans living within 3 miles of any 

source affected by this rule is 48 percent 

higher than the national average (19 

percent versus 13 percent); however, as 

noted previously, risks from this source 

category were found to be acceptable for 

all populations. Additionally, the 

proposed changes to the standard 

increase the level of environmental 

protection for all affected populations 

by ensuring no future emissions 

increases from the source category. The 

proximity analysis results and the 

details concerning their development 

are presented in the August 2012 

memorandum titled, Environmental 

Justice Review: Flexible Polyurethane 

Foam Production, a copy of which is 

available in the docket for this action 

(EPA–HQ–OAR–2012–0510). 

List of Subjects in 40 CFR Part 63 

Environmental protection, Air 

pollution control, Hazardous 

substances, Reporting and 

recordkeeping requirements. 

Dated: September 26, 2013. 

Gina McCarthy, 

Administrator. 

For the reasons stated in the 

preamble, the Environmental Protection 

agency (EPA) proposes to amend title 

40, chapter I, of the Code of Federal 

Regulations (CFR) as follows: 

PART 63—[AMENDED] 

■ 1. The authority citation for part 63 

continues to read as follows: 

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

Subpart III—National Emission 

Standards for Hazardous Air Pollutants 

for Flexible Polyurethane Foam 

Production 

■ 2. Section 63.1290 is amended by: 

■ a. Revising paragraph (c); and 

■ b. Adding paragraphs (d) and (e). 

The additions and revisions read as 

follows: 

§ 63.1290 Applicability. 

* * * * * 

(c) A process meeting one of the 

following criteria listed in paragraphs 

(c)(1) and (2) of this section shall not be 

subject to the provisions of this subpart: 

(1) A process exclusively dedicated to 

the fabrication of flexible polyurethane 

foam; or 

(2) A research and development 

process. 

(d) Applicability of this subpart. (1) 

The emission limitations set forth in 

this subpart and the emission 

limitations referred to in this subpart 

shall apply at all times except during 

periods of non-operation of the affected 

source (or specific portion thereof) 

resulting in cessation of the emissions to 

which this subpart applies. 

(2) Equipment leak requirements of 

§ 63.1294 shall apply at all times except 

during periods of non-operation of the 

affected source (or specific portion 

thereof) in which the lines are drained 

and depressurized resulting in cessation 

of the emissions to which the 

equipment leak requirements apply. 

(3) The owner or operator shall not 

shut down items of equipment that are 

required or utilized for compliance with 

this subpart during times when 

emissions are being routed to such items 

of equipment if the shutdown would 

contravene requirements of this subpart 

applicable to such items of equipment. 

(4) General duty. At all times, the 

owner or operator must operate and 


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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. 

(e) Affirmative defense for violation of 

emission standards during malfunction. 

In response to an action to enforce the 

standards set forth in paragraphs 

§§ 63.1293, 63.1294, 63.1297, 63.1298, 

63.1300, and 63.1301, the owner or 

operator may assert an affirmative 

defense to a claim for civil penalties for 

violations of such standards that are 

caused by malfunction, as defined at 40 

CFR 63.2. Appropriate penalties may be 

assessed if the owner or operator fails to 

meet their burden of proving all of the 

requirements in the affirmative defense. 

The affirmative defense shall not be 

available for claims for injunctive relief. 

(1) Assertion of affirmative defense. 

To establish the affirmative defense in 

any action to enforce such a standard, 

the owner or operator must timely meet 

the reporting requirements in paragraph 

(e)(2) of this section, and must prove by 

a preponderance of evidence that: 

(i) The violation: 

(A) Was caused by a sudden, 

infrequent, and unavoidable failure of 

air pollution control equipment, process 

equipment, or a process to operate in a 

normal or usual manner; and 

(B) Could not have been prevented 

through careful planning, proper design 

or better operation and maintenance 

practices; and 

(C) Did not stem from any activity or 

event that could have been foreseen and 

avoided, or planned for; and 

(D) Was not part of a recurring pattern 

indicative of inadequate design, 

operation, or maintenance; and 

(ii) Repairs were made as 

expeditiously as possible when a 

violation occurred; and 

(iii) The frequency, amount, and 

duration of the violation (including any 

bypass) were minimized to the 

maximum extent practicable; and 

(iv) If the violation resulted from a 

bypass of control equipment or a 

process, then the bypass was 

unavoidable to prevent loss of life, 

personal injury, or severe property 

damage; and 

(v) All possible steps were taken to 

minimize the impact of the violation on 

ambient air quality, the environment, 

and human health; and 

(vi) All emissions monitoring and 

control systems were kept in operation 

if at all possible, consistent with safety 

and good air pollution control practices; 

and 

(vii) All of the actions in response to 

the violation were documented by 

properly signed, contemporaneous 

operating logs; and 

(viii) At all times, the affected source 

was operated in a manner consistent 

with good practices for minimizing 

emissions; and 

(ix) A written root cause analysis has 

been prepared, the purpose of which is 

to determine, correct, and eliminate the 

primary causes of the malfunction and 

the violation resulting from the 

malfunction event at issue. The analysis 

shall also specify, using best monitoring 

methods and engineering judgment, the 

amount of any emissions that were the 

result of the malfunction. 

(2) Report. The owner or operator 

seeking to assert an affirmative defense 

shall submit a written report to the 

Administrator with all necessary 

supporting documentation, that 

explains how it has met the 

requirements set forth in paragraph 

(e)(1) of this section. This affirmative 

defense report shall be included in the 

first periodic compliance, deviation 

report or excess emission report 

otherwise required after the initial 

occurrence of the violation of the 

relevant standard (which may be the 

end of any applicable averaging period). 

If such compliance, deviation report or 

excess emission report is due less than 

45 days after the initial occurrence of 

the violation, the affirmative defense 

report may be included in the second 

compliance, deviation report or excess 

emission report due after the initial 

occurrence of the violation of the 

relevant standard. 

■ 3. Section 63.1291 is amended by 

revising paragraph (a) to read as follows: 

§ 63.1291 Compliance schedule. 

(a) Existing affected sources shall be 

in compliance with all provisions of this 

subpart no later than October 8, 2001, 

with the exception of § 63.1297. 

Affected sources subject to the 

requirements of § 63.1297 shall be in 

compliance with the requirements of 

this section on or before [DATE 90 

DAYS AFTER DATE OF PUBLICATION 

OF FINAL RULE IN THE FEDERAL 

REGISTER]. 

* * * * * 

■ 4. Section 63.1292 is amended by: 

■ a. Adding a definition for ‘‘affirmative 

defense’’ in alphabetical order; 

■ b. Revising the definitions for ‘‘HAPbased,’’ ‘‘Reconstructed source,’’ 

‘‘Storage vessel’’ and ‘‘Transfer pump’’; 

and 

■ c. Removing the definitions for ‘‘Highpressure mixhead,’’ ‘‘Indentation Force 

Deflection (IFD),’’ ‘‘In HAP ABA 

service,’’ ‘‘Recovery device,’’ ‘‘Run of 

foam,’’ and ‘‘Transfer vehicle’’. 

The additions and revisions read as 

follows: 

§ 63.1292 Definitions. 

* * * * * 

Affirmative defense means, in the 

context of an enforcement proceeding, a 

response or defense put forward by a 

defendant, regarding which the 

defendant has the burden of proof, and 

the merits of which are independently 

and objectively evaluated in a judicial 

or administrative proceeding. 

* * * * * 

HAP-based means to contain 5 

percent (by weight) or more of HAP. 

This applies to equipment cleaners, 

mixhead flushes, mold release agents 

and ABA. 

* * * * * 

Reconstructed source means an 

affected source undergoing 

reconstruction, as defined in subpart A 

of this part. For the purposes of this 

subpart, process modifications made to 

stop using HAP ABA or HAP-based 

ABA to meet the requirements of this 

subpart shall not be counted in 

determining whether or not a change or 

replacement meets the definition of 

reconstruction. 

* * * * * 

Storage vessel means a tank or other 

vessel that is used to store diisocyanates 

for use in the production of flexible 

polyurethane foam. Storage vessels do 

not include vessels with capacities 

smaller than 38 cubic meters (or 10,000 

gallons). 

Transfer pump means all pumps used 

to transport diisocyanates that are not 

metering pumps. 

■ 5. Section 63.1293 is revised to read 

as follows: 

§ 63.1293 Standards for slabstock flexible 

polyurethane foam production. 

Each owner or operator of a new or 

existing slabstock affected source shall 

comply with §§ 63.1294, 63.1297 and 

63.1298. 

■ 6. Section 63.1294 is amended by 

revising paragraphs (a)(1)(i), (c) and 


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(d)(2)(ii), and by adding paragraph 

(d)(2)(iii) to read as follows: 

§ 63.1294 Standards for slabstock flexible 

polyurethane foam production— 

diisocyanate emissions. 

(a) * * * 

(1) * * * 

(i) During each unloading event, the 

vapor return line shall be inspected for 

leaks by visual, audible, or an 

instrumental detection method. 

* * * * * 

(c) Other components in diisocyanate 

service. If evidence of a leak is found by 

visual, audible, or an instrumental 

detection method, it shall be repaired as 

soon as practicable, but not later than 15 

calendar days after it is detected, except 

as provided in paragraph (d) of this 

section. The first attempt at repair shall 

be made no later than 5 calendar days 

after each leak is detected. 

(d) * * * 

(2) * * * 

(ii) The purged material is collected 

and destroyed or recovered in a control 

device when repair procedures are 

effected, and 

(iii) Repair is completed as soon as 

practicable, but not later than 6 months 

after the leak was detected. 

* * * * * 

§ 63.1295 [Removed and Reserved] 

■ 7. Remove and reserve § 63.1295. 

§ 63.1296 [Removed and Reserved] 

■ 8. Remove and reserve § 63.1296. 

■ 9. Revise § 63.1297 to read as follows: 

§ 63.1297 Standards for slabstock flexible 

polyurethane foam production—HAP ABA. 

Each owner or operator of a new or 

existing slabstock affected source shall 

not use HAP or a HAP-based material as 

an ABA. 

■ 10. Revise § 63.1298 to read as 

follows: 

§ 63.1298 Standards for slabstock flexible 

polyurethane foam production—HAP 

emissions from equipment cleaning. 

Each owner or operator of a new or 

existing slabstock affected source shall 

not use HAP or a HAP-based material as 

an equipment cleaner. 

§ 63.1299 [Removed and Reserved] 

■ 11. Remove and reserve § 63.1299. 

■ 12. Revise § 63.1302 to read as 

follows: 

§ 63.1302 Applicability of subpart A 

requirements. 

The owner or operator of an affected 

source shall comply with the applicable 

requirements of subpart A of this part, 

as specified in Table 1 of this subpart. 

■ 13. Section 63.1303 is amended by: 

■ a. Revising paragraph (a) introductory 

text; 

■ b. Removing paragraphs (a)(3) and 

(a)(4); 

■ c. Revising paragraph (b); and 

■ d. Removing paragraphs (c), (d) and 

(e). 

The revisions read as follows: 

§ 63.1303 Monitoring requirements. 

* * * * * 

(a) Monitoring requirements for 

storage vessel carbon adsorption 

systems. Each owner or operator using 

a carbon adsorption system to meet the 

requirements of § 63.1294(a) shall 

monitor the concentration level of the 

HAP or the organic compounds in the 

exhaust vent stream (or outlet stream 

exhaust) from the carbon adsorption 

system at the frequency specified in 

paragraphs (a)(1) or (2) of this section. 

* * * * * 

(b) Each owner or operator using a 

carbon adsorption system to meet the 

requirements of § 63.1294(a) shall 

monitor the concentration level of total 

organic compounds in the exhaust vent 

stream (or outlet stream exhaust) from 

the carbon adsorption system using 40 

CFR part 60, Appendix A, Method 25A, 

reported as propane. The measurement 

shall be conducted over at least one 5- 

minute interval during which the 

storage vessel is being filled. 

§ 63.1304 [Removed and Reserved] 

■ 14. Remove and reserve § 63.1304. 

■ 15. Section 63.1306 is amended by: 

■ a. Removing paragraph (c); 

■ b. Redesigating paragraphs (d) and (e) 

as paragraphs (c) and (d); 

■ c. Revising newly redesignated 

paragraphs (c) introductory text and 

(c)(3); 

■ d. Revising newly redesignated 

paragraph (d); 

■ e. Revising paragraph (f); 

■ f. Redesignating paragraph (g) as 

paragraph (e); 

■ g. Revising newly redesignated 

paragraphs (e)(1) and (2); and 

■ h. Adding a new paragraph (g). 

The addition and revisions read as 

follows: 

§ 63.1306 Reporting requirements. 

* * * * * 

(c) Notification of compliance status. 

Each affected source shall submit a 

notification of compliance status report 

no later than 180 days after the 

compliance date. For slabstock affected 

sources, this report shall contain the 

information listed in paragraphs (c)(1) 

through (3) of this section, as applicable. 

This report shall contain the 

information listed in paragraph (c)(4) of 

this section for molded foam processes 

and in paragraph (c)(5) of this section 

for rebond foam processes. 

* * * * * 

(3) A statement that the slabstock 

foam affected source is in compliance 

with §§ 63.1297 and 63.1298, or a 

statement that slabstock foam processes 

at an affected source are in compliance 

with §§ 63.1297 and 63.1298. 

* * * * * 

(d) Semiannual reports. Each 

slabstock affected source shall submit a 

report containing the information 

specified in paragraphs (d)(1) through 

(3) of this section semiannually no later 

than 60 days after the end of each 180 

day period. The first report shall be 

submitted no later than 240 days after 

the date that the Notification of 

Compliance Status is due and shall 

cover the 6-month period beginning on 

the date that the Notification of 

Compliance Status Report is due. 

(1) For sources complying with the 

storage vessel provisions of § 63.1294(a) 

using a carbon adsorption system, 

unloading events that occurred after 

breakthrough was detected and before 

the carbon was replaced. 

(2) Any equipment leaks that were not 

repaired in accordance with 

§§ 63.1294(b)(2)(iii) and 63.1294(c). 

(3) Any leaks in vapor return lines 

that were not repaired in accordance 

with § 63.1294(a)(1)(ii). 

(e) * * * 

(1) The compliance certification shall 

be based on information consistent with 

that contained in § 63.1308, as 

applicable. 

(2) A compliance certification 

required pursuant to a state or local 

operating permit program may be used 

to satisfy the requirements of this 

section, provided that the compliance 

certification is based on information 

consistent with that contained in 

§ 63.1308, and provided that the 

Administrator has approved the state or 

local operating permit program under 

part 70 of this chapter. 

* * * * * 

(f) Malfunction reports. If a source 

fails to meet an applicable standard, 

slabstock affected sources must report 

such events in the next semiannual 

report and molded and rebond affected 

sources must report such events in the 

next annual compliance certification. 

Report the number of failures to meet an 

applicable standard. For each instance, 

report the date, time and duration of 

each failure. For each failure, the report 

must include a list of the affected 

sources or equipment, an estimate of the 

volume of each regulated pollutant 

emitted over any emission limit, and a 


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description of the method used to 

estimate the emissions. 

(g) Within 60 days after the date of 

completing each performance test (as 

defined in § 63.2), you must submit the 

results of the performance tests required 

by this subpart according to the 

methods specified in paragraphs (g)(1) 

or (g)(2) of this section. 

(1) For data collected using test 

methods supported by the EPAprovided software, the owner or 

operator shall submit the results of the 

performance test to the EPA by direct 

computer-to-computer electronic 

transfer via EPA-provided software, 

unless otherwise approved by the 

Administrator. Owners or operators, 

who claim that some of the information 

being submitted for performance tests is 

confidential business information (CBI), 

must submit a complete file using EPAprovided software that includes 

information claimed to be CBI on a 

compact disk, flash drive, or other 

commonly used electronic storage 

media to the EPA. The electronic media 

must be clearly marked as CBI and 

mailed to U.S. EPA/OAQPS/CORE CBI 

Office, Attention: WebFIRE 

Administrator, MD C404–02, 4930 Old 

Page Rd., Durham, NC 27703. The same 

file with the CBI omitted must be 

submitted to the EPA by direct 

computer-to-computer electronic 

transfer via EPA-provided software. 

(2) For any performance test 

conducted using test methods that are 

not compatible with the EPA-provided 

software, the owner or operator shall 

submit the results of the performance 

test to the Administrator at the 

appropriate address listed in § 63.13. 

■ 16. Section 63.1307 is amended by: 

■ a. Removing paragraph (a)(2) and 

redesignating paragraphs (a)(3) and 

(a)(4) as paragraphs (a)(2) and (a)(3); 

■ b. Revising the newly redesignated 

paragraphs (a)(2) introductory text, 

(a)(2)(ii), and (a)(3) introductory text; 

■ c. Revising paragraph (b)(1); 

■ d. Revising paragraphs (b)(3) 

introductory text, (b)(3)(i) introductory 

text and (b)(3)(i)(B); 

■ e. Removing paragraph (b)(3)(i)(C); 

■ f. Revising paragraphs (b)(3)(ii) 

introductory text and (b)(3)(ii)(A); 

■ g. Removing paragraph (b)(3)(ii)(D); 

■ h. Redesignating paragraphs 

(b)(3)(ii)(E) through (b)(3)(ii)(H) as 

(b)(3)(ii)(D) through (b)(3)(ii)(G); 

■ i. Revising paragraph (c); 

■ j. Removing paragraph (d); 

■ k. Redesignating paragraphs (e) 

through (h) as (d) through (g); 

■ l. Revising newly redesignated 

paragraph (e); and 

■ m. Adding paragraph (h). 

The additions and revisions read as 

follows: 

§ 63.1307 Recordkeeping requirements. 

* * * * * 

(a) * * * 

(2) For storage vessels complying 

through the use of a carbon adsorption 

system, paragraphs (a)(2)(i) or (ii), and 

paragraph (a)(2)(iii) of this section. 

* * * * * 

(ii) For affected sources monitoring at 

an interval no greater than 20 percent of 

the carbon replacement interval, in 

accordance with § 63.1303(a)(2), the 

records listed in paragraphs (a)(2)(ii)(A) 

and (B) of this section. 

* * * * * 

(3) For storage vessels complying 

through the use of a vapor return line, 

paragraphs (a)(3)(i) through (iii) of this 

section. 

* * * * * 

(b) * * * (1) A list of components in 

diisocyanate service. 

* * * * * 

(3) When a leak is detected as 

specified in §§ 63.1294(b)(2)(ii) and 

63.1294(c), the requirements listed in 

paragraphs (b)(3)(i) and (ii) of this 

section apply: 

(i) Leaking equipment shall be 

identified in accordance with the 

requirements in paragraphs (b)(3)(i)(A) 

and (B) of this section. 

* * * * * 

(B) The identification on equipment 

may be removed after it has been 

repaired. 

(ii) The information in paragraphs 

(b)(2)(ii)(A) through (G) shall be 

recorded for leaking components. 

(A) The operator identification 

number and the equipment 

identification number. 

* * * * * 

(c) The owner or operator of an 

affected source subject to § 63.1297 shall 

maintain a product data sheet for each 

ABA used which includes the HAP 

content, in kg of HAP/kg solids (lb HAP/ 

lb solids). 

* * * * * 

(e) The owner or operator of an 

affected source following the 

compliance methods in § 63.1308(b)(1) 

shall maintain records of each use of a 

vapor return line during unloading, of 

any leaks detected during unloading, 

and of repairs of leaks detected during 

unloading. 

* * * * * 

(h) Malfunction records. Records shall 

be kept as specified in paragraphs (h)(1) 

through (3) of this section for affected 

sources. Records are not required for 

emission points that do not require 

control under this subpart. 

(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 the 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 volume 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 

§ 63.1290(d) and any corrective actions 

taken to return the affected unit to its 

normal or usual manner of operation. 

■ 17. Section 63.1308 is amended by: 

■ a. Revising paragraph (a) introductory 

text; 

■ b. Revising paragraphs (b)(3), (b)(6), 

and (c); 

■ c. Removing paragraph (d); and 

■ d. Redesignating paragraph (e) as (d). 

The revisions read as follows: 

§ 63.1308 Compliance demonstrations. 

(a) For each affected source, 

compliance with the requirements 

described in Tables 2 and 3 of this 

subpart shall mean compliance with the 

requirements contained in §§ 63.1293 

through 63.1301, absent any credible 

evidence to the contrary. 

* * * * * 

(b) * * * 

(3) For each affected source 

complying with § 63.1294(a) in 

accordance with § 63.1294(a)(2) through 

the alternative monitoring procedures in 

§ 63.1303(a)(2), each unloading event 

that the diisocyanate storage vessel is 

not equipped with a carbon adsorption 

system, each time that the carbon 

adsorption system is not monitored for 

breakthrough in accordance with 

§ 63.1303(b)(1) or (2) at the interval 

established in the design analysis, and 

each unloading event that occurs when 

the carbon is not replaced after an 

indication of breakthrough; 

* * * * * 

(6) For each affected source 

complying with § 63.1294(c), each 

calendar day after 5 calendar days after 

detection of a leak that a first attempt at 

repair has not been made, and the 

earlier of each calendar day after 15 

calendar days after detection of a leak 

that a leak is not repaired, or if a leak 

is not repaired as soon as practicable, 

each subsequent calendar day (with the 

exception of situations meeting the 

criteria of § 63.1294(d)). 

(c) Slabstock affected sources. For 

slabstock foam affected sources, failure 

to meet the requirements contained in 

§§ 63.1297 and 63.1298, respectively, 

shall be considered a violation of this 

subpart. Violation of each item listed in 


EMCDONALD on DSK67QTVN1PROD with PROPOSALS2
Federal Register / Vol. 78, No. 213 / Monday, November 4, 2013 / Proposed Rules 66137 

the following paragraphs shall be 

considered a separate violation. 

(1) For each slabstock foam affected 

source subject to the provisions in 

§ 63.1297, each calendar day that a HAP 

ABA or HAP-based material is used as 

an ABA; 

(2) For each slabstock foam affected 

source subject to the provisions of 

§ 63.1298, each calendar day that a 

HAP-based material is used as an 

equipment cleaner. 

* * * * * 

■ 18. Section 63.1309 is amended by 

removing paragraph (b)(4) and 

redesignating paragraph (b)(5) as (b)(4). 

■ 19. Remove Table 1 to Subpart III of 

part 63. 

■ 20. Redesignate Table 2 to Subpart III 

of Part 63 as Table 1 to Subpart III of 

Part 63 and amend newly redesignated 

Table 1 by: 

■ a. Revising the heading of newly 

redesignated Table 1; 

■ b. Removing entry § 63.6(e)(1)–(2); 

■ c. Adding entries § 63.6(e)(1)(i), 

§ 63.6(e)(1)(ii) and § 63.6(e)(1)(iii); 

■ d. Removing entry § 63.6(e)(3); 

■ e. Adding entry § 63.6(e)(2)–(3): 

■ f. Removing entry § 63.6(f)–(g); 

■ g. Adding entries § 63.6(f)(1), 

§ 63.6(f)(2)–(3), and § 63.6(g); 

■ h. Removing entry § 63.10(a)–(b); 

■ i. Adding entries § 63.10(a), 

§ 63.10(b)(1), § 63.10(b)(2)(i), 

§ 63.10(b)(2)(ii); § 63.10(b)(2)(iii); 

§ 63.10(b)(2)(iv)–(xi); § 63.10(b)(2)(xii); 

§ 63.10(b)(2)(xiii), § 63.10(b)(2)(xiv); and 

§ 63.10(b)(3); 

■ j. Removing entry § 63.10(d)(4)–(5); 

and 

■ k. Adding entries § 63.10(d)(4) and 

§ 63.10(d)(5). 

The additions and revisions read as 

follows: 

TABLE 1 TO SUBPART III OF PART 63—APPLICABILITY OF GENERAL PROVISIONS (40 CFR PART 63, SUBPART A) TO

SUBPART III 

Subpart A reference Applies to 

subpart III Comment 

*******

§ 63.6(e)(1)(i) ............................................ NO .................... See § 63.1290(d)(4) for general duty requirement. 

§ 63.6(e)(1)(ii) ........................................... NO. 

§ 63.6(e)(1)(iii) .......................................... YES. 

§ 63.6(e)(2)–(3) ........................................ NO. 

§ 63.6(f)(1) ................................................ NO. 

§ 63.6(f)(2)–(3) ......................................... YES. 

§ 63.6(g) ................................................... YES. 

* * * * * * * 

§ 63.10(a) ................................................. YES. 

§ 63.10(b)(1) ............................................. YES. 

§ 63.10(b)(2)(i) .......................................... NO. 

§ 63.10(b)(2)(ii) ......................................... NO .................... See § 63.1307(h) for recordkeeping of (1) date, time and duration; (2) listing of affected source or equipment and an estimate of the volume of each regulated 

pollutant emitted over the standard; and (3) actions to minimize emissions and 

any actions taken at the discretion of the owner or operator to prevent recurrence of the failure to meet an applicable requirement. 

§ 63.10(b)(2)(iii) ........................................ YES. 

§ 63.10(b)(2)(iv)–(xi) ................................. NO. 

§ 63.10(b)(2)(xii) ....................................... YES. 

§ 63.10(b)(2)(xiii) ...................................... NO. 

§ 63.10(b)(2)(xiv) ...................................... YES. 

§ 63.10(b)(3) ............................................. YES. 

*******

§ 63.10(d)(4) ............................................. YES. 

§ 63.10(d)(5) ............................................. NO .................... See § 63.1306(f) for malfunction reporting requirements. 

*******

■ 21. Redesignate Table 3 to Subpart III 

of Part 63 as Table 2 to Subpart III of 

Part 63 and amend newly redesignated 

Table 2 by: 

■ a. Revising the heading for newly 

redesignated Table 2; 

■ b. Removing entries for HAP ABA 

storage vessels § 63.1295, HAP ABA 

pumps § 63.1296(a), HAP ABA valves 

§ 63.1296(b), HAP ABA connectors 

§ 63.1296(c), Pressure relief devices 

§ 63.1296(d), Open-ended valves or 

lines § 63.1296(e), and Production line 

§ 63.1297; and 

■ c. Adding an entry for ABAs 

§ 63.1297. 

The revisions and addition read as 

follows: 


EMCDONALD on DSK67QTVN1PROD with PROPOSALS2
66138 Federal Register / Vol. 78, No. 213 / Monday, November 4, 2013 / Proposed Rules 

TABLE 2 TO SUBPART III OF PART 63—COMPLIANCE REQUIREMENTS FOR SLABSTOCK FOAM PRODUCTION AFFECTED

SOURCES

Emission point 

Emission point 

compliance 

option 

Emission, 

work practice, 

and equipment 

standards 

Monitoring Recordkeeping Reporting 

*******

ABAs § 63.1297 .................................................................... N/A § 63.1297 ........................ § 63.1307(e) ........................

■ 22. Remove Table 4 to Subpart III of 

Part 63. 

■ 23. Redesignate Table 5 to Subpart III 

of Part 63 as Table 3 to Subpart III of 

Part 63 and amend newly redesignated 

Table 3 by revising the heading to read 

as follows: 

Table 3 to Subpart III of Part 63— 

Compliance Requirements for Molded 

and Rebond Foam Production Affected 

Sources 

* * * * * 

[FR Doc. 2013–24276 Filed 11–1–13; 8:45 am] 

BILLING CODE 6560–50–P 


EMCDONALD on DSK67QTVN1PROD with PROPOSALS2