January 31, 2014



# National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins; Pesticide Active Ingredient Production; and Polyether

Polyols Production

Summary of Public Comments and Responses on Proposed Rule (77 FR 1268, January 9, 2012)

U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division Research Triangle Park, NC 27711ii 

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## FOREWORD

This document provides responses to public comments on the U.S. Environmental Protection Agency’s (EPA’s) proposed “ National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins; Pesticide Active Ingredient Production; and Polyether Polyols Production .” The EPA Docket contains all comment letters submitted and are available for viewing at the EPA Docket Center Reading Room, or electronically through http://www.regulations.gov by searching Docket ID No. EPA

- HQ

- OAR

- 2011

- 0435 by docket

number.

This document provides a summary of the public comments entered into the docket regarding specific issues and topics related to the development of the proposed amendments to the subject rules and the EPA’s responses to those comments. Within each comment summary, the EPA provides in parentheses one or more Docket ID numbers for commenters who raised particular issues. However, the list of commenter ID numbers is not meant to be exhaustive. The EPA does not individually identify each and every commenter who made a certain point in all instances, particularly in cases where multiple commenters express essentially identical arguments. Although portions of the preamble to the final rule are paraphrased in this document, to the extent any ambiguity is introduced by paraphrasing, the preamble itself remains the definitive

statement of the rationale for the final rule.iv 

## TABLE OF CONTENTS

FOREWORD

................................ ................................ ................................ ............................ iii

TABLE OF CONTENTS

................................ ................................ ................................ .......... iv

ACRONYMS AND A BBREVIATIONS

................................ ................................ .................... v 1.0 Background

................................ ................................ ................................ .......................... 1

2.0 Risk

- Related Assessment and Standards

................................ ................................ ............... 3

2.1 Risk Assessment Data and Methodology

................................ ................................ ....... 3

2.2 Consideration of Risks from Entire Facilities, Industrial Clusters, and Other Sources in

Risk Assessment

................................ ................................ ................................ ......... 17

2.3 Consideration of Demographics in Risk Assessment

................................ ................... 19

2.4 Additional Standards to Address Risks

................................ ................................ ........ 21

3.0 Technology Review Assessment and Standards

................................ ................................ .. 26

4.0 Startup, Shutdown, and Malfunction Exemption/Affirmative Defense Provisions

............... 29

4.1 Startup, Shutdown, and Malfunction Exemption

................................ .......................... 29

4.2 Affirmative Defense Provisions

................................ ................................ ................... 33

5.0 Electronic Reporting Requirements

................................ ................................ .................... 44

6.0 Pressure Relief Device Provisions

................................ ................................ ...................... 46

7.0 Source Category Specific Comments

................................ ................................ .................. 50

7.1 Source Category Specific Comments

– Group IV Polymers and Resins

....................... 50

7.2 Source Category Specific Comments

– Pesticide Active Ingredient Production

........... 52

7.3 Source Category Specific Comments

– Polyether Polyols Production

.......................... 53

8.0 Other Comments

................................ ................................ ................................ ................ 55v 

## ACRONYMS AND ABBREVIATIONS

Acronym/

Abbreviation Definition

Act or CAA Clean Air Act

ABS Acrylonitrile Butadiene Styrene

ACA American Coatings Association

ACC American Chemistry Council

ACT Achievable Control Technology

AEGL Acute Exposure Guideline Level

AMOS Ample Margin of Safety

AN Acrylonitrile

BBDR Biologically

- Based Dose

- Response

Cal OEHHA California Office of Environmental Health Hazard Assessment

CBI Confidential Business Information

CDX Central Data Exchange

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CFR Code of Federal Regulations

CHIEF Clearinghouse for Emission Inventories and Emissions Factors

CIIT Chemical Industry Institute of Toxicology

CMAS Chemical Manufacturing Area Source

CRWI Coalition for Responsible Waste Incineration

EJ Environmental Justice

EJSEAT Environmental Justice Strategic Enforcement Assessment Tool

EO Executive Order

EPA U.S. Environmental Protection Agency

EPCRA Emergency Planning and Community Right

- to

- Know Act

ERPG Emergency Response Planning Guideline

ERT Electronic Reporting Tool

FOIA Freedom of Information Act

FR Federal Register

HAP Hazardous Air Pollutants

HCl Hydrogen Chloride

HF Hydrogen Fluoride

HON National Emission Standards for Organic Hazardous Air Pollutants From the

Synthetic Organic Chemical Manufacturing Industry HQ Hazard Quotient

ICR Information Collection Request

IRIS Integrated Risk Information System

LDAR Leak Detection and Repair

MACT Maximum Achievable Control Technology NAAQS National Ambient Air Quality Standards

NACAA National Association of Clean Air Agenciesvi

Acronym/

Abbreviation Definition

NAS National Academy of Sciences

NATA National Air Toxics Assessment

NEI National Emissions Inventory

NESHAP National Emission Standards for Hazardous Air Pollutants

NRDC Natural Resources Defense Council

PAI Pesticide Active Ingredient Production

P&R IV Group IV Polymers and Resins

PB Persistent and Bioaccumulative

PEPO Polyether Polyols Production

PET Polyethylene Terephthalate

POM Polycyclic Organic Matter

ppmv Parts Per Million by Volume

PRD Pressure Release Device

REL Reference Exposure Level

RfC Reference Concentration

RfD Reference Dose RQ Reportable Quantity

RTR Risk and Technology Review

SAB Science Advisory Board

SAN Styrene Acrylonitrile Resin

SARA Superfund Amendments and Reauthorization Act SCAQMD South Coast Air Quality Management District

SISNOSE Significant Economic Impact on a Substantial Number of Small Entities

SOCMA Society of Chemical Manufacturers and Affiliates

SOCMI Synthetic Organic Chemical Manufacturing Industry

SSM Startup, Shutdown, and Malfunction

TOSHI Target Organ

- Specific Hazard Index

TP A Thermal Polyaspartic Acid

tpy Tons Per Year

URE Unit Risk Estimatevii 

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## 1.0 Background

On January 9, 2012 (77 FR 1268), the U.S. Environmental Protection Agency (EPA) proposed to revise the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Group IV Polymers and Resins (P&R IV); Pesticide Active Ingredient Production (PAI) ; and Polyether Polyols Production (PEPO), under the authority of section 112 of the Clean Air Act (CAA). This document presents summaries of the comments that were submitted in response to this action and our responses to those comments. The comments to w hich we are responding were submitted in 21 letters from industry representatives, governmental entities, environmental advocacy groups, and citizens during the public comment period. In addition, the EPA received

three comment letters and sets of material s from industry and environmental advocacy group commenters following the close of the comment period. Although the EPA is not required to respond to these late comments, to the extent practicable, the EPA often attempts to respond to

late comments and our responses to such comments are also presented in this document. A list of the commenters, their affiliations, and the EPA docket number assigned to their correspondence is presented in Table 1

- 1.

TABLE 1

- 1. LIST OF COMMENTERS ON PROPOSED NATIONAL EMISSI ON

STANDARDS FOR HAZARDOUS AIR POLLUTANTS

Docket Number a b Commenter and Affiliation

26 K. Watts, private citizen

28 Vinson Hellwig and Robert Colby, National

Association of Clean Air Agencies (NACAA)

Air Toxics Committee

29 & 39 Russell Wozniak, The Dow Chemical

Company

30 & 42 David Darling and Timothy Serie, American

Coatings Association (ACA)

31 Melvin Keener, Coalition for Responsible

Waste Incineration (CRWI)

32 Ann Mason, American Chemistry Council

(ACC)

33 Tom Herman, Zeon Chemicals, L.P.

34 Colleen Greene, private citizen

37 Steven Silz

- Carson, private citizen

38 Chris Manley, Eastman Chemical Company

41 Lorraine Krupa Gershman, ACC

44 Russell Frye, SSM Coalition

45 Frederick Fedri, Occidental Chemical

Corporation

46 Daniel Moss, Society of Chemical

Manufacturers and Affiliates (SOCMA)2 47 Brady Wassom, Croda Inc.

48 John Dege, DuPont

49 Matthew Todd, Residual Risk Coalition

50 Andrew Jaques, The Acrylonitrile (AN) Group 51 (Part 1 of 6) 52 (Part 2 of 6) 53 (Part 3 of 6)

54 (Part 4 of 6) 55 (Part 5 of 6) 56 (Part 6 of 6) Neil Carman, et.al., Sierra Club, Earthjustice,

Clean Air Muscatine, California Communities Against Air Toxics, Ohio Valley Environmental Coalition, Del Amo Action Committee, Air Alliance Houston, Coalition for a Safe Environment, and California Safe

Schools

57 (Late Comment) Emma Cheuse and James Pew, Earthjustice on

behalf of the Sierra Club and California Communities Against Toxics

60 (Late Comment) Lorraine Krupa Gershman, ACC

61 (Late Comment) Liane P latt, The Dow Chemical Company

a Document ID identifies comments found in Docket No. EPA

- HQ

- OAR

- 2011

- 0435 by

document number.

b Individual comments from the public (and attachments submitted with comments) submitted to the docket are assigned a unique 4

- digit docket number that follows the base docket number (i.e., EPA

- HQ

- OAR

- 2011

- 0435

- XXXX, where “XXXX” represents the unique 4

- di git document docket number). The unique document docket numbers presented in this table and document represent that unique docket number without the preceding 0s. For example, docket number EPA

- HQ

- OAR

- 2011

- 0435

- 0026 is presented as 26 in this

table and wit hin the text of this document.

The following sections provide a summary of the comments received on the proposed standards for the P&R IV, PAI, and PEPO NESHAP, as well as the EPA’s responses to these comments. Nineteen commenters are represented by 26 public comment submission entries represented in the docket and submitted on the proposal within the public comment period. We

also received three comment submission entries from three commenters that had also submitted comments on the proposal within the public comment period. Some of the comment submission entries include several file attachments. For example, one commenter submission (docketed under 6 Docket IDs, or comment submission entries) includes a total of 110 files (one 108

- page comment letter an d 109 attachments). For the purpose of orderly presentation, the comments have been categorized under the following topics:

Section 2: Risk

- Related Assessment and Standards Section 3: Technology Review Assessment and Standards Section 4: Startup, Shutdown, and Malfunction Exemption/Affirmative Defense

Provisions Section 5: Electronic Reporting Requirements

Section 6: Pressure Relief Device Provisions Section 7: Source Category Specific Comments

Section 8: Other Comments3



## 2.0 Risk

- Related Assessment and Sta ndards

2.1 Risk Assessment Data and Methodology

Comment 2.1.1: Commenter 28 is pleased to see the EPA placing increasing reliance on CalEPA Chronic Reference Exposure Level (REL) acute exposure threshold values and recommends continuing the use of RELs ov er Acute Exposure Guideline Level (AEGL) and Emergency Response Planning Guideline (ERPG) values, which the commenter does not feel are appropriate for assessing daily human exposure scenarios. Response 2.1.1: As discussed in the preamble to the proposed rule (77 FR 1278), the EPA considers various acute health effect reference values, including the California acute REL, and AEGL and ERPG values, in assessing the potential for risks from acute exposures. The REL is one of the preferred acute values for use in risk and technology reviews (RTR), as endorsed by the EPA’s Science Advisory Board (SAB).

Comment 2.1.2: Commenters 32 and 49 urge the EPA to use the Chemical Industry Institute of Toxicology (CIIT) cancer dose

- response value for formaldehyde establis hed in 1999 rather than the 1991 Integrated Risk Information System (IRIS) dose

- response value, in keeping with the Information Quality Act and Executive Order 13563, which states that the regulatory system must “be based on the best available science.” Co mmenter 38 states that the CIIT formaldehyde value is a biologically based dose

- response (BBDR) model, which they claim better reflects the available science than the allegedly outdated and overly conservative IRIS value. Both commenters also point out tha t the use of the CIIT BBDR model would fit with the recommendations of an expert panel of the National Academy of Science (NAS) that reviewed the formaldehyde values in 2011. In contrast, commenter 51 supports the EPA in its decision to use the current IR IS values for formaldehyde and methanol while reviews of the health benchmark values for chemicals are

undertaken. Response 2.1.2: In 2004, the EPA determined that the CIIT cancer dose

- response value for formaldehyde (5.5 x 10

- 9 per μg/m 3 ) was based on be tter science than the IRIS cancer dose

response value (1.3 x 10

- 5 per μg/m 3 ), and we switched from using the IRIS value to the CIIT value in risk assessments supporting regulatory actions. Subsequent research published by the EPA suggested that the CIIT mo del was not appropriate and, in 2010, the EPA returned to using the 1991 IRIS value. The EPA has been working on revising the formaldehyde IRIS assessment and the NAS completed its review of the EPA’s draft assessment in April of 2011. 1 The EPA will follow the NAS Report recommendations and will present results obtained by implementing the BBDR model for formaldehyde. The EPA will compare these estimates with those currently presented in the External Review draft of the assessment and will discuss their str engths and weaknesses. As recommended by the NAS committee, appropriate sensitivity and uncertainty analyses will be an integral component of implementing the BBDR model. In the interim, we will present findings using the 1991 IRIS value as a primary estim ate and the EPA may also consider other information as the science evolves. We note that, except in the case of the PAI source category, formaldehyde was not generally a primary driver of the risks for these source categories, and risks due to formaldehyd e

1 http://www.nap.edu/catalog.php?record_id=131424

emissions did not change our decisions about acceptability and ample margin of safety of the risks associated with any of these source categories, or about our technology reviews for them. Therefore, in this rulemaking the choice between using the IRIS v alue or the CIIT value makes no difference in the regulatory outcome.

Comment 2.1.3: Commenter 50 states that the EPA is using an allegedly outdated cancer unit risk estimate (URE) value for acrylonitrile (AN) from IRIS, which leads to a claimed overstatement of risks, even though those risk values are already at “acceptable” levels for t he source categories in this proposal. The commenter states that use of that value is a violation of the Information Quality Act guidelines and President Obama’s directive on scientific integrity and regulatory review in Executive Order 13563. The commente r notes several data updates and peer reviewed evaluations of AN and states that the EPA should use this information rather than waiting for an updated IRIS assessment, particularly a review conducted by the North Carolina Science Advisory Board that was c ompleted in 2009. While an updated AN IRIS assessment was released by the EPA in June 2011 for comment, the commenter states there are significant concerns with the draft IRIS assessment. The commenter opines that if the EPA considers the updated IRIS asse ssment before the final rule, then the EPA should also consider the comments made by the AN Group and others on the draft assessment. Response 2.1.3: The EPA acrylonitrile IRIS assessment is currently under review (for detailed information on the new sche dule see the IRIS Track website available online at http://cfpub.epa.gov/ncea/iristrac/index.cfm?fuseaction=viewChemical.showChemical&sw_id=1

017 ). As part of the AN assessment review, the EPA will consider all scientific data available, comments from the public (including those that may be submitted by the AN Group) and recommendations made by the NAS in the 2009 report referred by the commenter. Howev er, until completion of the IRIS AN assessment (projected posting date is the second quarter of 2014), the current EPA URE is considered to be the best

- available science and has therefore been used in assessing cancer risk for this rulemaking. Because the updated EPA AN IRIS assessment released in June 2011 is still in draft form and undergoing peer review, it will not be considered for this rulemaking. As noted by the commenter, the EPA’s risk assessment for these categories shows that residual risks are a lready at acceptable levels and that the standards provide an ample margin of safety to protect public health. Therefore, the use of the URE for AN, even if the commenter were correct that it might overstate risks, did not drive any regulatory

decisions in this rulemaking that would affect the commenter.

Comment 2.1.4: Commenter 51 states that the EPA cannot assume that hazardous air pollutants (HAP) with no peer

- reviewed reference values for cancer or non

- cancer effects have

zero risk. The commenter state s that the EPA must select health protective values based on the information it has or, at a minimum, add an uncertainty factor to the risk estimates. The commenter also requests that the EPA clearly state which HAP emitted by these source categories have no health reference values. The commenter states that the EPA must set a regulatory deadline no later than 8 years from the finalization of these rules to review the current residual risk analysis and perform another residual risk rulemaking to incorporate new toxicity information for HAP with toxicity information currently under review and HAP that currently

lack reference values. Response 2.1.4: This issue was addressed by the EPA’s SAB in its May 10, 2010 (EPA

SAB

- 10

- 007) response to the EPA Administrato r;5

http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA

- SAB

- 10

- 007

- unsigned.pdf . In that response, the SAB Panel recommended that, for HAP that do

not have dose

- response values from the EPA’s hierarchy list, the EPA should consider and utilize, as appropriate, additional sources for such values that have undergone adequate and rigorous scientific peer r eview. The SAB panel further recommended that the inclusion of additional sources of dose

- response values into the EPA’s hierarchy should be adequately documented in a transparent manner in any residual risk assessment case study. We agree with this approa ch and have considered other sources of dose

- response data when conducting our risk determinations under RTR. However, in some instances no sources of information beyond the EPA’s hierarchy are available. The EPA disagrees that we must set an 8

- year regul atory deadline to review the current residual risk analysis and perform another residual risk rulemaking to incorporate new toxicity information for HAP with toxicity information currently under review or lacking reference

values. Pursuant to CAA section 1 12(f)(2)(A), the EPA is required to perform a residual risk review within 8 years after initial promulgation of a MACT standard; unlike the technology review required under CAA 112(d)(6), this is not a recurring statutory requirement. The EPA’s subsequent risk based review of NESHAP is subject to the agency’s discretion and decisions to conduct any such reviews will be informed by the specific facts applicable to the source categories at issue. We do not agree that it is appropriate, at this time, to set a binding regulatory deadline for such a review for the source categories addressed in this rule. While we are not yet at the point where all HAP have dose

- response values, we are generally capable of deriving reasonable risk estimates for those HAP which do minate the risks from any one source category. In the course of each residual risk assessment, should we encounter HAP without dose

response values which carry the potential to create significant risks, we shall clearly point those

out as uncertainties and target them for future IRIS assessments. Moreover, as additional dose

response values become available, the EPA will incorporate these dose

- response values into future risk assessments. The EPA disagrees with the commenter that we did not state which HAP currently have no reference value. In the risk assessment document, there is a table for each source category that lists all the HAP emitted by the source category, and indicates whether there is an available cancer, chronic noncancer, and/or acute dose

- re sponse value.

Comment 2.1.5: Commenter 51 is concerned that the EPA is assessing noncancer hazards for lead solely through reliance on the 2008 National Ambient Air Quality Standards (NAAQS) for lead. The commenter states that this is relevant information but it is not protective enough to assess health risk from lead. The commenter goes on to describe that the NAAQS was created to protect the average exposed member of the population from an IQ point loss above 2 points, not to protect the “most exposed” a nd most vulnerable member of that population. The commenter adds that the lead NAAQS was also designed to address only a single pollutant (elemental lead), while section 112(f)(2) requires the EPA to assess and address health risk from

the combined effect of a source category on the most exposed person. According to the commenter, there is significant new information since the scientific review closed on the NAAQS suggesting that a stronger standard is needed. The commenter adds that lead can

interact with other pollutants, such as arsenic, to cause greater harm than lead exposure alone. Finally, the commenter notes that section 112(f)(2) requires the EPA to create an “ample margin of safety to protect public health, ” while the NAAQS only must satisfy the te st to provide an6

“adequate margin of safety.” The commenter concludes that rather than only relying on the NAAQS to assess health risk from lead, the EPA should use all of the best available, most current information, including California’s lead health ben chmark. Response 2.1.5: We disagree with the comment that the lead NAAQS was designed to protect the average exposed member of the population from an IQ loss above 2 points. First, the primary lead NAAQS targets protection of the most susceptible group in the human population

–

c hildren

– and is designed to protect against adverse effects to children’s most sensitive organ

system

– the developing neurological system. (See 73 FR at 66975, 66976.) Second, the primary NAAQS for lead is specifically targeted at those children living n ear major sources of lead, such as secondary smelters. (See 73 FR at 67002/3 “in applying the evidence

- based framework, we are focused on a subpopulation of U.S. children, those living near air sources and more likely to be exposed at the level of the stan dard”; to the same effect see 73 FR 67000/3:“The framework in effect focuses on the sensitive subpopulation that is the group of children living near sources and more likely to be exposed at the level of the standard. The evidence

- based framework

estimates a mean air

- related IQ loss for this subpopulation of children; it does not estimate a mean for all U.S. children”; 73 FR 67005/1:“the air

- related IQ loss framework provides estimates for the mean air

- related IQ loss of a subset of the population of U.S. c hildren, and there are uncertainties associated with those estimates. It provides estimates for that subset of children likely to be exposed to the level of the standard, which is generally expected to be the subpopulation of children living near sources w ho are likely to be most highly exposed.”) In addition, in reviewing and sustaining the primary lead NAAQS, we note that the U.S. Court of Appeals for the D.C. Circuit specifically noted that the rule was targeted to protect children living near lead sourc es: “EPA explained that the scientific evidence showing the impact of lead exposure in young children in the United States led it ‘to give greater prominence to children as the sensitive subpopulation in this review’ and to focus its revision of the lead N AAQS on the ‘sensitive subpopulation that is the group of children living near [lead emission] sources and more likely to be exposed at the level of the standard.’ Given the scientific evidence on which it relied, the EPA’s decision to base the revised lea d NAAQS on protecting the subset of children likely to be exposed to airborne lead at the level of the standard was not arbitrary or capricious.” Coalition of Battery Recyclers v. EPA , 604 F.3d 613, 618 (D.C. Cir. 2010). In response to the comment that the EPA is required to assess the combined effect of a source category on the most exposed person, we agree and consider our analysis to have done this. The approach used to calculate chronic non

- cancer risks, developing the target

- organ specific hazard index

, specifically considers the combined effect of multiple pollutants on the same target organ. Any new scientific information concerning lead will be reviewed in accordance with the next NAAQS review process. The commenter also makes the legal argument that the primary lead NAAQS provides an “adequate” margin of safety, but that section 112(f)(2) requires that a residual risk standard provide an “ample” margin of safety, reasoning from this that a NAAQS cannot just be substituted as the measure for evaluatin g acceptability of risk and that some greater level of protection is required. The EPA disagrees with the commenter that section 112(f)(2) requires that in all cases standards must be more protective than what is achieved by attainment of a primary NAAQS. Nothing in section 112(f)(2) requires a conclusion that a standard that results in attainment of a primary NAAQS might not also in fact provide an ample margin of safety to7

pretct public health. Further, to the extent the commenter’s argument rests on the difference
between ‘adequate’ and ‘ample’ margin of safety, the argument is misplaced. 2 The EPA is considering the primary lead NAAQS

-- which incorporates an adequate margin of safety

-- merely to determine whether lead risks from air

- borne lead from P&R I V, PEPO or PAI facilities are acceptable or not. The acutal margin

- of

- safety determinations for this rule are

conducted in accord with the two

- step framework set forth in the Benzene NESHAP and the en banc opinion in the D.C. Circuit’s ruling in the Vinyl Chloride case. See not only Vinyl Chloride

, 824 F.2d 1146, 1165

- 66 (D.C. Cir. 1987), but also NRDC v. EPA , 902 F.2d 962, 973

- 74 (D.C. Cir. 1990) (distinguishing the NAAQS process, whereby the margin of safety analysis is incorporated as part of the standar d without a two

- step analysis, from residual risk
determinations). 3 Using that framework, with its consideration of costs, cost

- effectiveness, technological feasibility, and other factors set out in the Benzene NESHAP, at proposal we did not identify any a dditional controls beyond those that would need to be implemented to ensure an acceptable level of risk with an ample margin of safety to protect public health.

Comment 2.1.6: Commenter 51 states that the EPA must account for the increased susceptibility of children and pregnant women to HAP emissions from this source category in the risk assessment based on findings of the NAS review and CalEPA studies. The commenter is concerned that the EPA’s failure to include an adequate evaluation of increased early life susceptibility to HAP emissions systematically underestimates risk from the source categories for several HAP (polycyclic organic matter (POM), formaldehyde, arsenic, cadmium) and provides additional information supporting the need for these pollutant

- specific analyses and information on the guidelines and other materials that the EPA should use to conduct such analyses. To satisfy its duty to protect children, the EPA must follow the best available science. At a minimum, the EPA must adopt the followi ng: 1. California Office of Environmental Health Hazard Assessment (Cal OEHHA) Cancer Guidelines (Age

- Dependent Adjustment Factors) for all carcinogens and include pre

natal susceptibility, and

2. Child

- Specific Reference Doses (for Non

- Cancer Impacts), and

3. Children‘s Default Safety Factor of At Least Ten (for Non

- Cancer Chronic & Acute Impacts), where specific information on children‘s vulnerability is unavailable. Response 2.1.6: We disagree with the general comment that the EPA should adopt the

Cal OEHHA c hild

-

protective scientific approach on cancer. The EPA has a hierarchy of appropriate health benchmark values and in general, this hierarchy places greater weight on the EPA derived health benchmarks than those from other agencies (see http://www.epa.gov/t tn/atw/nata1999/99pdfs/healtheffectsinfo.pdf). Notably, this hierarchy favoring EPA benchmarks (when they exist) over all others has been endorsed by the SAB. Further, the EPA is currently evaluating whether it is appropriate to use the CalEPA child

specif ic reference doses, and we note that because there are currently no such values for HAP

2 Indeed, the EPA’s utilization of a standard which also incorporates an adequate margin of safety to evaluate acceptability of risk, which is the fir st step in the section 112(f)(2) residual risk assessment, is an added conservative (i.e. protective) element in its approach here.

3 The court was referring to the predecessor provision to the current section 112(f), but its analysis is equally applicable to the revised provision.8

inhalation, their current utility would be limited to persistent and bioaccumulative (PB)

- HAP, which may be associated with non

- negligible ingestion exposures. That is, before using these

child

- specific reference doses (RfDs), the EPA would need to evaluate whether they have been appropriately derived. We also disagree with the comment that the risk assessment for these source categories does not consider the groups that may be most at

- risk in its risk assessments (e.g., pregnant women). When the EPA derives exposure reference concentrations and unit risk estimates for metal HAP, it also considers the most sensitive populations identified in the available literature,

and importantly, these are the values used in our risk assessments (see US EPA. (2002). A review of the reference dose and reference concentration processes. EPA/630/P

- 02/002F. Risk Assessment Forum, Washington DC. Available online at http://www.epa.gov/raf/pu blications/pdfs/rfd

- final.pdf). With respect to maternal exposure in utero specifically, we are unaware of literature that would allow for a robust characterization of risk during this stage of development. We acknowledge that population subgroups, includi ng children, may have a potential for risk that is greater than the general population due to greater relative exposure and/or greater susceptibility to the toxicant. As explained in previous actions, including the final synthetic organic chemical manufact uring industry (SOCMI) hazardous organic NESHAP (HON) RTR (71

FR 76610

- 76611), the assessments we undertake to estimate risk account for this potential vulnerability. With respect to exposure, the risk assessments we perform implicitly account for this gre ater potential for exposure by assuming lifetime exposure, in which populations are conservatively presumed to be exposed to airborne concentrations at their residence continuously, 24 hours per day for a full lifetime, including childhood. With regard to children‘s potentially greater susceptibility to non

- cancer toxicants, the assessments rely on EPA (or comparable) hazard identification and dose

- response values which have been developed to be protective for all subgroups of the general population, includ ing children. For example, a review of the chronic reference value process concluded that the EPA’s reference concentration (RfC) derivation processes adequately considered potential susceptibility of different subgroups with specific consideration of chi ldren, such that the resultant RfC values pertain to the full human population including sensitive subgroups, “a phrase which is inclusive of childhood.” With respect to cancer, the EPA uses the age

- dependent adjustment factor approach referred to by the c ommenter, but limits the use of those factors only to carcinogenic pollutants that are known to act via mutagenic mode of action, in contrast to the OEHHA approach, which uses them across the board for all carcinogens regardless of mode of

action. In lieu of chemical

- specific data on which age or life

- stage specific risk estimates or potencies can be determined, default age dependent adjustment factors can be applied when assessing cancer risk for early

- life exposures to chemicals which cause cancer through a mutagenic mode. At the present time, there have been no peer

- reviewed assessments that explicitly make a determination that any of the chemicals emitted by the source categories considered in this action cause cancer through a mutagenic mode of action. However, the estimated risks must also be considered in the context of the full set of assumptions used for this risk assessment. For example, we used a health

- protective assumption of a 70

- year exposure duration in our risk estimates; however, using the n ational average residency time of 12 years would reduce the estimate of risk by roughly a factor of 6. Our unit risk estimates for HAP are considered a plausible upper

- bound estimate; actual potency is likely to be lower and some of

which could be as low a s zero. After considering these and other factors, we continue to consider9

the risks from emissions after application of the revisions to the Maximum Achievable Control Technology (MACT) standards for these source categories to provide an ample margin of s afety (consistent with the Benzene NESHAP framework). The EPA disagrees with the commenter’s statement that the EPA should use California EPA’s child specific

- reference doses for school site risk assessments 4 in order to address the potential for early

- lif

e susceptibility. The EPA methods for assessing hazard and dose

- response relationships for HAPs and developing RfCs and cancer risk estimates, as noted above, specifically address the potential for early

- life susceptibility. Whenever data indicate increase d susceptibility of a developmental lifestage or of a population group, those data are factored into the analysis. When data are inadequate to understand the effects of a specific pollutant on sensitive subpopulations, which for some pollutants may include children, the EPA’s risk assessment methods take that into account to ensure that resulting assessments address the possibility that such subpopulations might be more or less sensitive. Further, in the RTR risk assessments performed using the agency’s pre ferred dose

- response values, exposure is characterized as occurring all day and every day over a lifetime, rather than only during specific periods of time during childhood.

Comment 2.1.7: Commenter 28 is concerned that the EPA has not taken steps to redu ce the target organ

- specific hazard index (TOSHI) to below 1 for the PAI source category. Response 2.1.7: Pollutant

- specific RfCs are not absolute thresholds, but estimates of chronic inhalation exposures at or below which health effects would not be expec ted to occur, including in sensitive subgroups. Further, RfCs are developed using a health

- protective approach (see uncertainty discussion in section 10.2 of the Draft Residual Risk Assessment for 7 Source Categories (Docket Item No. EPA

- HQ

- OAR

- 2011

- 0435

- 0 018)), and TOSHI values of 1 or less are (like RfC levels) generally considered to carry no appreciable risk of adverse health effects. That said, the EPA generally does not draw bright lines of acceptability regarding cancer or noncancer risks from source category HAP emissions, for several reasons. There are uncertainties in the emissions and health effects information regarding the source category in question that should be considered when deciding exactly what level of cancer and noncancer

risk should b e considered acceptable. In addition, the source category

- specific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultaneously consider all potential health impacts

-- chronic and acute, cancer and n oncancer, and multipathway,

-- along with their uncertainties, when determining the acceptable level of source category risk. In other words, we look at the risk numbers within the context of the uncertainty associated with emissions, health benchmark valu es and, in the case of TOSHI values, target organ effect. The Benzene NESHAP decision framework of 1989 acknowledged this; in today’s world, such flexibility is even more imperative, because new information relevant to the question of risk acceptability is being developed all the time, and the accuracy and uncertainty of each

4 We note that California EPA’s use of these numerical values, which do not exist for inhalation exposures, is limited to the context of risk assessment at proposed or existing California school sites and does not even extend to their Air Hot Spots Risk Assessment program. Further the guidance for the California EPA school site assessment program specifies the use of California OEHHA or U.S. EPA IRIS values in the absence of the school site risk

assessment child

- specific values ( Cal OEHHA, 2004

- http://www.oehha.ca.gov/public_info/public/kids/pdf/SchoolscreenFinal.pdf ).10

piece of information must be considered in a weight

- of

- evidence approach for each decision. This relevant body of information is growing fast (and it will continue to grow even faster)

, necessitating a flexible weight

- of

- evidence approach that acknowledges both complexity and uncertainty in the simplest and most transparent way possible. While this challenge is formidable, it is nonetheless the goal of the EPA’s RTR decision

- making, and it is the goal of the risk assessment to provide the information to support the decision

- making process. For all of the P&R IV source categories and for the PEPO source category, the TOSHIs

at both the actual and MACT

- allowable emission levels are below 1.0. For the PAI source category, the TOSHI at the actual emission level is 0.7, and at the estimated MACT

- allowable emission level, the TOSHI could be as high as 4. For this source category, weighing all the health risk factors, including the TOSHI at the actual emissions and the TOSHI at the potential

MACT

- allowable emission level, considering the uncertainty associated with the associated emissions estimate, the EPA determined that the risks were acceptable. As part of the second step ample margin of saf

ety analysis, we did look for additional controls and process improvements that might further reduce risks in a cost

- effective, technically feasible manner. In this case, we did not find any additional cost

- effective controls and ultimately concluded that the current PAI MACT standards’ level of control brought risks to an acceptable level and is also the level of control that results in public health being protected with an ample margin of safety.

See 77 FR at 1298

- 99.

Comment 2.1.8: Commenter 28 opines that the EPA should consider risk based on potential or allowable emissions because emissions and associated impacts could increase over time, and analyses based on actual emissions may underestimate residual risk. The commenter

notes that the thresholds f or major source status were based on maximum potential

- to

- emit, and permits are issued based on potential emissions. Further, the commenter argues that limiting the scope of risk assessments to actual emissions would be inconsistent with the applicability sections of the MACT standards. While acknowledging that the EPA has relied less on actual emissions than it has in the past, the commenter would like to see more reliance on the use of

allowable emissions. In contrast, commenter 49 states that the EPA can not lawfully use the MACT allowable emissions in risk assessments and residual risk determinations because the EPA has allegedly failed to provide any reasoned explanation why risk assessments based on actual emissions are inadequate. The commenter states that the language of section 112 requires that the EPA report on the actual health effects for people living in the vicinity of affected sources, which the commenter claims clearly signals that Congress expected the EPA to focus on actual risk and not hypo thetical risk in implementing the requirements of section 112(f). In addition, because the risk methodology already reflects numerous conservative assumptions, the commenter asserts it makes no sense to add another layer of conservatism and the EPA has not provided any data to indicate analyses based on actual emissions result in negative bias. Response 2.1.8: Consistent with previous risk assessments, the EPA considers both allowable and actual emissions in assessing chronic exposure and risk under section 112(f)(2). (See, e.g., National Emission Standards for Coke Oven Batteries (70 FR 19998

- 19999, April 15, 2005); proposed and final National Emission Standards for Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry (71 FR 34428, June 14, 2006, and 71 FR 76603, December 21, 2006). This approach is both reasonable and consistent with the flexibility inherent in the Benzene NESHAP framework for assessing ample margin of safety. As11

a general matter, modeling allowable em ission levels is inherently reasonable since this reflects the maximum level sources could emit and still comply with national emission standards. But it is also reasonable to consider actual emissions, where such data are available, in both steps of the

r isk analysis. See National Emission Standards for Coke Oven Batteries, 70 FR 19992, 19998 (April 15, 2005). We disagree with commenter 28’s claim that the additional consideration of actual emissions conflicts with either the statutory major source definit ion that is based on potential to emit, or with applicability thresholds in MACT standards that are tied to major source status. Those thresholds still have the same full effect for determining the applicability of section 112 standards that they had befor e we conducted our residual risk assessments. Moreover, our risk assessments necessarily included information regarding sources with potential

– not necessarily actual

– emissions at major source levels. We also note that our use of allowable emission leve ls in the risk assessments in this rulemaking did not result in revising the previously established standards due to risk concerns. Therefore, our consideration of allowable emissions in the risk assessments did not result in regulatory decisions that affe ct commenter 49, and commenter 49’s objections to our use of allowable emissions are moot.

Comment 2.1.9: Commenters 28 and 51 state that the use of the census block centroid dilutes the effect of sources’ emissions, as the maximum point of impact can be far from the centroid and may be at or near a facility’s property line, and suggested that the risks for a source category be based on concentrations at the fenceline and beyo nd and include risks to the maximally exposed individual. Commenter 51 states that using the census block centroids conflicts with the SAB recommendation that the EPA consider specific locations of residences, which may be closer to the fenceline than the census block centroids. The commenter adds that this is particularly inexcusable, given that an adjustment for the property line location was made

for the assessment of acute risks. Response 2.1.9: As we have explained in previous RTRs, such as the SOCMI H ON RTR (71 FR 76603, December 21, 2006), the EPA believes that, in a national

- scale assessment of lifetime inhalation exposures and health risks from facilities in a source category, it is appropriate to identify exposure locations where it may be reasonab ly expected that an individual will spend a majority of his or her lifetime. Further, in determining chronic risks, the EPA believes that it is appropriate to use census block information on where people actually reside, rather than points on a fence

- line, to locate the estimation of exposures and risks to individuals living near such facilities. If a population did indeed live just outside of the fenceline of a facility, then it would result in a census block near the fenceline. Census blocks are the fines t resolution available as part of the nationwide population data (as developed by the US Census Bureau); each is typically comprised of approximately 40 people or about 10 households. In EPA risk assessments, the geographic centroid of each census

block co ntaining at least one person is used to represent the location where all the people in that census block live. The census block centroid with the highest estimated exposure then becomes the location of maximum exposure, and the entire population of that ce nsus block experiences the maximum individual risk. In some cases, because actual residence locations may be closer to or farther from facility emission points, this may result in an overestimate or underestimate of the actual annual concentrations (althou gh there is no systematic bias for average levels). Given the relatively small dimensions of census blocks in densely populated areas, there is little uncertainty introduced by using the census block centroids in lieu of actual residence locations.

There i s the potential for more uncertainty when census blocks are larger, although there is still12

no bias on average. 5 The EPA concludes that the most appropriate locations at which to estimate chronic exposures and risks are the census block centroids because: 1) census blocks are the finest resolution available in the national census data, 2) facility fencelines do not typically represent locations where chronic exposures are likely because people do not typically live near the fenceline, and 3) there is no bi as introduced into the estimate of the MIR by using

census block centroid locations.

Comment 2.1.10: Commenter 51 states that the EPA has failed to collect and use the best available emissions data from these source categories by relying on the 2005 Natio nal Emission Inventory (NEI) to form its dataset. The commenter states that the EPA should have issued an Information Collection Request (ICR) to gather actual emission test data from the facilities in these source categories. The commenter further states that the EPA’s use of emission factors to develop its inventories underestimates actual emissions, as evidenced by studies in Texas. To improve its inventories, the commenter states that the EPA needs to require remote sensing and continuous monitoring to track and measure emissions, with technologies such as differential absorption light detection and ranging, solar occultation flux, CEREX UV Hound, and Accusense. The commenter also states that in addition or as an alternative, the EPA should require conti nuous emissions monitoring or performance tests every year, at a minimum, as it has done for other source categories. The commenter urges the EPA to collect the basic emissions information it needs before finalizing the rule, and barring that, the EPA shou ld set stronger standards to protect public health under section 112(f)(2) to try to make up for the likely underestimated emissions, particularly from fugitive sources and flares. As an alternative, the commenter suggests the EPA commit to collect this da ta by a certain date within 3 years and commit to review the residual risk determination and 112(d)(6) decision within 1 year after gathering this data. Response 2.1.10: The emissions data for the risk assessments in the proposed rules were derived from th e NEI as well as data provided by industry. The sources of the data are
documented in the docket. As stated in the EPA’s documentation on the 2005 NEI ( http://www.epa.gov/ttn/chief/net/2005_nei_point.pdf ), “[t]he 2005 NEI is a composite of emission estimates generated by state and local regulatory agencies, tribes, industry, and EPA. Because the estimates originated from a variety of sources and estimatio n methods, as well as for differing purposes, they will in turn vary in quality, pollutants included, level of detail, and geographic coverage. However, this compilation of emissions estimates represents the best available information to date.” More genera lly, we note that the 2005 NEI for HAP is greatly improved since the first NEI compilation using 1996 data, and that it is sufficiently accurate and complete and constitutes the best information the EPA has to use in our analysis. We have worked diligently with state and local agencies and tribes to improve emission inventories over the years, and we have instituted a number of quality assurance (QA) measures to improve data received from state and local agencies since 1996. Documentation for the 2005 NEI p oint source emissions inventory is available on the EPA's Clearinghouse for Inventories and Emissions Factors (CHIEF) website, http://www.epa.gov/ttn/chief/net/2005inventory.html . Quality as surance and augmentation procedures used for the 2005 NEI point sources are contained in the report, EI

5 There is no bias because a residence has an equal likelihood of being farther from a source, compared to the block centroid’s distance, as it does being nearer to a source.13

Quality Assurance and Data Augmentation for Point Sources, posted at: http://www.epa.g ov/ttn/chief/net/2002inventory.html . The 2005 NEI data have been reviewed extensively internally and externally during a 9

- month effort as part of the development of the 2005 National Air Toxics Assessment (NATA). As part of the 2005 NATA review, more than one million records for HAP were revised. Updated test data and emission point information were received during the public comment period that addressed inaccuracies in the data. For these source categories, the EPA‘s review included an evaluation of faci lities contained in the source category, the emissions units expected to be included for the processes in the source categories, coordinates and stack parameters, and the HAP compounds and emission levels typically seen. The NEI data were also reviewed by industry trade groups, including the American Chemistry Council (ACC) and the Society of Chemical Manufacturers and Affiliates (SOCMA), as well as several state air agencies, and the EPA revised the NEI data where we concluded comments from this review sup

ported such adjustment. Section II.B of the January 9, 2012, proposal preamble (77 FR 1275) set forth a detailed explanation of the review that the EPA performed on the emissions data for the source categories subject to this final rule. In addition, as pa rt of the January 9, 2012, proposal, we made the data sets available for review using a RTR data review tool in the docket and solicited comments on the data sets. The RTR review of the proposal data sets act as another external third party review mechanis m in addition to the external 2005 NATA review of the RTR data sets. Several opportunities have been provided to review the data used in the current proposal. In addition, on February 4, 2013, the EPA asked NACAA to review the emissions data for PAI, PEPO, and P&R IV facilities in several states. The states of Texas and Louisiana were also asked to review emissions data for the PAI, PEPO, and P&R IV facilities in their state. Through enhanced NEI QA procedures, 2005 NATA review, industry, state, and

NACAA r eview, public comment on proposal files, source category

- specific engineering reviews, and modeling, improvements to the data files have been made. We believe the data sets used in this rulemaking are sufficiently accurate and complete and constitute the b est information the EPA has concerning the emissions and risk from these source categories for conducting RTRs.

Comment 2.1.11: Commenter 51 states that it is unclear whether the EPA considered all HAP in the risk assessment, including those from currentl y uncontrolled emission points for which the EPA proposes to set standards. The commenter states that the EPA should confirm that

it has assessed the health risks from all emitted HAP. Response 2.1.11: We confirm with this response that we considered all H AP emitted from the source category in the risk assessments for the P&R IV, PAI, and PEPO source categories, including HAP emitted from currently uncontrolled emission points.

Comment 2.1.12: Commenter 51 states that the EPA should analyze risk based on w hat emissions may occur above the existing MACT standards, considering malfunctions and violations. The commenter states that the EPA must assess public health risk based on the

likelihood of such events in addition to the use of the MACT

- allowable emissio ns number. The commenter suggests that the EPA develop and apply a factor to the risk results based on

available malfunction and violation data. Response 2.1.12: We disagree with the commenter that emissions that exceed standards and are violations, whethe r or not caused by malfunction events, should be considered as part of the risk analysis for purposes of determining the sufficiency of pre

- existing standards, particularly when we are revising the standards to eliminate any excused periods of non

-14

complian ce during upset periods. The purpose of the risk review is to evaluate whether the

emission limits

-- the “standards promulgated pursuant to subsection (d)” not the non

compliance with those standards (section 112(f)(2)(A)

-- should be made more stringent to reduce the risk posed after compliance with the underlying MACT standard. To the extent that a source is violating the underlying MACT standard, no tightening of the emission standard under the residual risk rule will avoid or militate against such viol ations. 6 In other words, a source that is violating the emission standard promulgated under section 112(d) would not be any more likely to be able to avoid such violations and comply with a different presumably more stringent standard promulgated under sec tion 112(f). Such events are violations and subject to enforcement by the EPA, the states or citizens, and an action for injunctive relief is the most effective means to address violations whether or not they are caused by malfunctions if an

emissions even t poses a significant health or environmental risk. Furthermore, the conservative estimates built into the acute risk assessment are sufficient

to gauge worst

- case potential acute health effects. The conservative estimates built in to the

assessment includ e worst

- case meteorology, emissions at ten (or two) times the maximum peak emission rate from all point sources simultaneously, and the sum of the maximum impact of each emission source, regardless of receptor location. Thus, even if we were to consider em issions that are in violation of the standard, we do not believe that they would result in any different level of control than we are promulgating here.

Comment 2.1.13: Commenter 51 states that the EPA has not used a high enough

emissions factor to accoun t for acute risks. The EPA used an emissions factor of 10 or 2 and has not demonstrated that this factor is high enough to assess true acute risks to the most

- exposed individual, considering that the EPA has noted that peak emission events could reach 74 t imes the annual average for some industries and that with a control device failure, a facility could emit 100 times more than its usual emissions if it usually controls 99% of emissions. Response 2.1.13: The acute risk assessment methodology uses a tiered, iterative approach that begins with an assessment of an approximation of a worst

- case exposure. To this end, the assumption that peak 1

- hour emissions are equal to 10 (or 2) times the average 1

- hour emissions rate is only one of the worst

- case assumptions that we made in our acute health risk screening analysis. Other worst

- case assumptions included:

 For facilities with multiple emission points, peak 1

- hour emissions were assumed to occur at all emission points at the same time.

 For facilities with multip le emission points, 1

- hour concentrations at each receptor were assumed to be the sum of the maximum concentrations due to each emission point, regardless of whether those maximum concentrations occurred during the

same hour.

 Worst

- case meteorology (from one year of local meteorology) was assumed to occur at the same time the peak emission rates occur. The recommended EPA local

- scale dispersion model, AERMOD, is used for simulating atmospheric dispersion.

 A person was assumed to be located downwind at the point of maximum impact during this same 1

- hour period, but no nearer to the source than 100 meters.

6 In this regard, note that the affirmative defense for malfunctions is a defense to civil penalties only, not to liability.

The malfunction event remains a violation.15

 The maximum impact was compared to multiple short

- term health benchmarks for the chemical being assessed to determine if a possible acute health risk might exist. Based on industry

- specific information, we determined that a refined emissions multiplier of 2, rather than a multiplier of 10, better represents the peak hourly emission rates for several facilities in the PEPO and P&R IV source categories. Refer to a separate memorandum in the docket ( Emissions Data and Acute Risk Factor Used in Residual Risk Modeling; Pesticide Active Ingredients, Polyether Polyols, and Group IV Polymers and Resins ) for a detailed description of how the refined emissions multipli ers were developed for the source categories. With regards to the failure of a control device, this would constitute a violation of the emission standard. The acute risk emissions factor is designed to account for fluctuations in emissions for facilities

c omplying with the standards, not for facilities in non

- compliance. Therefore, it would be inappropriate to use the emissions factor suggested by the commenter for purposes of determining whether the MACT standards’ current requirements are in need of revis ion under section 112(f)(2).

Comment 2.1.14: Commenter 51 stated concern that the EPA failed to perform an adequate multipathway risk assessment. One reason the commenter states the assessment is inadequate is that it does not account for all the PB pollutants. The commenter asserts that the

EPA’s c hoice to restrict the multipathway screening assessment to only HAP that bioaccumulate is not supported by the 2003 Risk Assessment Guidance, because it ignores HAP that persist and accumulate in soils, including arsenic, nickel and other metals emitted by these source categories. Another reason the commenter believes the multipathway risk assessment is inadequate is that the EPA did not base the assessment on allowable emissions or consider emissions from malfunctions and violations. In addition, the comme nter notes that the EPA did not assess all exposure routes, did not use the information from the multipathway analysis in the overall risk analysis, and did not add the multipathway risk found to the inhalation risk. The commenter asserts that the EPA may not assume that risks under the multipathway threshold are not significant enough to require a full analysis and that the EPA gives no justification for cutting off the significance threshold at the 1

- in

- 1 million point. The commenter claims that, where th e EPA found multipathway risks above the thresholds, the EPA must take action to better protect people’s health based on this information. The commenter opines that the EPA should update the incidental soil ingestion factors it uses in its multipathway ris k assessments to fully account for the greater multipathway exposure and risk for children. Response 2.1.14: We disagree that the multipathway assessment is inadequate due to restrictions in the pollutants included in the screening assessment. I n the Air T

oxics Risk Assessment Reference Library, we developed the current PB

- HAP list considering all of the available information on persistence and bioaccumulation (see http://www.epa.gov/ttn/fera/risk_atra_main.html ) , specifically Volume 1 Appendix D)

. (The Air Toxics Risk Assessment Reference Library provides information on the fundamental principles of

risk

- based assessment for air toxics and how to apply those princip les in different settings (e.g., facility

- specific) as well as strategies for reducing risk at the local level.) This list considered HAP identified as PB

- HAP by other EPA Program Offices (e.g., the Great Waters Program), as well as information from the PB T profiler (see http://www.pbtprofiler.net/ ). This list was peer

reviewed by the SAB and found to be acceptable, and therefore we consider it to be reasonable for use in the RTR program. Based on these sources and the limited available information on the16

persistence and bioaccumulation of other HAP, we do not believe that the potential for multipathway risk from other HAP rises to the level of the PB

- HAP currently on the list.

As noted in the docket memo MACT Allowa ble Emissions and Risks for the Pesticide Active Ingredient, Polyether Polyols, and Polymers and Resins IV Production Source Categories (Docket Item No. EPA

- HQ

- OAR

- 2011

- 0435

- 0007), allowable risks were equal to actual risks for all of these source categori es, with one exception described below. Since (in most cases) actual risks equal allowable risks, the multipathway screening results presented based on actual emissions would be the same if based on allowable emissions. The one instance where actual

risks did not equal allowable risks was for the PAI source category. The halogenated process vents could have a maximum ratio of MACT allowable to actual emissions of 6:1, or allowable emissions could be 6 times higher than actual emissions. This ratio was then applied to emissions of hydrogen chloride and chlorine and the allowable TOSHI from this source category was estimated to be 3, while the actual TOSHI was estimated to be 0.7. However, these two HAP are not included in the multipathway analysis so there wo uld be no increase in multipathway results by including allowable emissions from this source category. We did not combine the inhalation and multipathway risk assessment results for each pollutant because it is inappropriate to do so. The multipathway risk assessment conducted for proposal was a screening

- level assessment (i.e., Tier 1). It used highly conservative assumptions designed to ensure that facilities with results below the screening threshold values did not have the potential for multipathway imp acts of concern. The screening scenario is a hypothetical scenario. It is inappropriate to combine the results of a refined inhalation assessment, which produces a quantitative result, with a screening

- level multipathway assessment, which produces a “yes/ no” result. In situations where we have previously summed the inhalation and multipathway assessment results (e.g., secondary lead smelters), it was for two refined assessments, and still serves as an overestimate of potential risks given that it is highly unlikely that the same receptor has the maximum results in both assessments. We disagree with the commenter that emissions that are violations of the standards should be considered as part of the risk analysis for purposes of determining whether the stand ards need to be revised under section 112(f)(2). The purpose of the risk review is to evaluate whether the emission limits should be made more stringent to reduce the risk posed after compliance with the underlying MACT standard. To the extent that a sourc e is violating the underlying MACT standard, no tightening of the emission standard under the residual risk rule will avoid or militate against such violations. In other words, a source that is violating the emission standard promulgated under section 112( d) would not be any more likely to be able to avoid such violations and comply with a different presumably more stringent standard promulgated under section 112(f). Such events are violations and subject to enforcement by the EPA, the states, or
citizens, and an action for injunctive relief is the most effective means to address violations whether or not they are caused by malfunctions if an emissions event poses a significant health

or environmental risk. We further note that we generally draw no bright li nes of acceptability regarding cancer or noncancer risks from source category HAP emissions, and that it is always important to consider the specific uncertainties of the emissions and health effects information regarding the source category in question wh en deciding exactly what level of cancer and noncancer risk should be considered acceptable. In addition, the source category

- specific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultaneously

cons ider all potential health impacts

-- chronic and acute, cancer and noncancer, and17

multipathway,

-- along with their uncertainties, when determining the acceptable level of source category risk. In other words, we look at the risk numbers within the context of uncertainty associated with emissions, health benchmark values and, in the case of cancer and noncancer risks, the health effect associated with exposure. The Benzene NESHAP decision framework of 1989 acknowledged this; in today’s world, such flexibili ty is even more imperative, because new information relevant to the question of risk acceptability is being developed all the time, and the accuracy and uncertainty of each piece of information must be considered in a weight

- of

evidence approach for each d ecision. This relevant body of information is growing fast (and it will continue to grow faster and faster), necessitating a flexible weight

- of

- evidence approach that acknowledges both complexity and uncertainty in the simplest and most transparent way

pos sible. While this challenge is formidable, it is nonetheless the goal of the EPA’s RTR

decision

- making, and it is the goal of the risk assessment to provide the information to support

the decision

- making process. Regarding incidental soil contamination, th e EPA has estimated risks from both direct and indirect pathways. Direct routes of exposure include direct ingestion of soil and exposure through dermal contact. However, because it has been demonstrated in past analyses that exposure levels associated wit h dermal contact are but a small fraction of exposure levels associated with ingestion and inhalation pathways, dermal exposures were not assessed for these source categories.



### 2.2 Consideration of Risks from Entire Facilities, Industrial Clusters, and

Ot her Sources in Risk Assessment

Comment 2.2.1: Commenter 51 states that the EPA should aggregate health risk. The commenter states that although the EPA does aggregate cancer and non

- cancer risks across pollutants, it should also do so for acute risks in a similar way to the chronic TOSHI for the same organ system or systems, and should also do so for all pollutants in the multipathway assessment. The commenter states that the EPA should also create a metric to assess the total, combined health risks, which include the acute, cancer, chronic non

- cancer, and multipathway risks for the
source category. Response 2.2.1: We have combined risk assessment results to the extent that it is appropriate to do so. We do consider the effect of mixtures of carcinogens. We do not use a TOSHI approach for acute noncancer like we do for chronic noncancer. We also do not combine the results of our inhalation and multipathway assessments. As described in the risk assessment report (available in the docket for this action), we do not sum results of the acute noncancer inhalation assessment to create a combined acute risk number that would represent the total acute risk for all pollutants that act in a similar way on the same organ system or systems (similar to the chronic TOSHI). As noted in previous responses,

the worst

- case acute screen is already a conservative scenario. That is, the acute screening

scenario assumes worst

- case meteorology, peak emissions for all emission points occurring currently and an individual being located at the site of maximum concentration for an hour. Thus, as noted in section 2.7.2 of the Draft Residual Risk Assessment for Seven Source Categories (Docket Item No. EPA

- HQ

- OAR

- 2011

- 0435

- 0018) , “because of the conservative nature of the acute inhalation sc reening and the variable nature of emissions and potential exposures, acute impacts were screened on an individual pollutant basis, not using the TOSHI approach.”18

We did not combine the inhalation and multipathway risk assessment results for each pollutan t because it is inappropriate to do so. The multipathway risk assessment conducted for proposal was a screening

- level assessment (i.e., Tier 1). It used highly conservative assumptions designed to ensure that facilities with results below the screening thr eshold values did not have the potential for multipathway impacts of concern. The screening scenario is a hypothetical scenario, and due to the theoretical construct of the screening model, exceedances of the thresholds are not directly translatable into e stimates of risk or hazard quotients for these facilities. In situations where we have previously summed the inhalation and multipathway assessment results (e.g., secondary lead smelters), it was for two refined assessments, and still

serves as a conservat ive overestimate of potential risks given that it is highly unlikely that the same receptor has the maximum results in both assessments.

Comment 2.2.2: Commenter 51 states that the EPA has failed to satisfy section 112(f)(2)

or to follow scientific recomm endations or the best available science regarding the need to assess the full, cumulative impact of HAP exposure for affected local communities, citing the EPA’s most recent report on the subject, titled Concepts, Methods and Data Sources for Cumulative

He alth Risk Assessment of Multiple Chemicals, Exposures and Effects: A Resource Document

, and recommendations by the SAB. The commenter states that for both its inhalation risk assessment and its multipathway risk assessment, the EPA fails to account for the impact of adding new air emissions to recent and past air emissions that the most

- exposed people have already experienced from these source categories. As a result, according to the commenter, the EPA fails to adequately assess the cumulative impact of ex posure to these source categories’ emissions. The commenter asserts that in many instances people living near these facilities already have background levels of past exposure and past pollution that increase their current

health risk. The commenter adds th at for areas like these, where there are multiple sources of air toxics and the individual sources in this category have emitted HAP for years, the EPA must address background as well as new health risk. In contrast, commenter 49 states that the EPA does not have authority to consider facility

wide risks because the CAA section 112(f)(2)(A) allegedly requires residual risk determinations to be conducted on a category

- by

- category basis and risk assessments to be focused exclusively

on emissions from sources in the category or subcategory. Response 2.2.2: The EPA conducted an assessment of the cumulative cancer risks from emitted carcinogens and the cumulative noncancer hazard indices from all emitted non

carcinogens affecting the same target organ system for both the source category emissions and the facility

- wide emissions. This assessment excludes background contributions because technical limitations in the data sets would be insufficient to conduct a meaningful analysis. While the incorporation of additio nal background concentrations from the environment in our risk assessments (including those from mobile sources and other industrial and area sources) could be technically challenging, they are neither mandated nor barred from our analysis. In developing t he decision framework in the Benzene NESHAP currently used for making residual risk decisions, the EPA rejected approaches that would have mandated consideration of background levels of pollution in assessing the acceptability of risk, concluding that comp arison of acceptable risk should not be associated with levels in polluted urban air (54 FR 38044, 38061, September 14, 1989). Background levels (including natural background) are not barred from the EPA‘s ample margin of safety (AMOS) analysis, and the EP A may consider them, as19

appropriate and as available, along with other factors, such as cost and technical feasibility, in the second step of its section 112(f) analysis. We disagree with the comment that we failed to consider or account for cumulative ris k.

The EPA modeled whole

-

facility risks for both chronic cancer and non

- cancer impacts to understand the risk contribution of the sources within these MACT categories. The individual cancer risks for each source category were aggregated for all carcinogens . In assessing noncancer hazard from chronic exposures for pollutants that have similar modes of action or (where this information is absent) that affect the same target organ, we aggregated the hazard quotients (HQ). This process creates, for each target organ, a TOSHI, defined as the sum of hazard quotients for individual HAP that affect the same organ or organ system. All TOSHI calculations presented here were based exclusively on effects occurring at the “critical dose” (i.e., the lowest dose that produ ces adverse health effects). Whole facility risks were estimated utilizing the 2005 NEI, with updated facility

- wide and source category data files developed by the EPA through emission data updates from industry, states, and NAC AA

. We also disagree with th e commenter’s assertion that additional quantitative assessment of risks from sources outside the source category is required under the statute. The statute requires the EPA to provide the quantitative risk information necessary to inform RTR regulatory

de cisions, and to this end, the EPA conducts a comprehensive assessment of the risks associated with exposure to the HAP emitted by the source category and supplements that with additional information that is available about other possible concurrent and rel evant risks.



### 2.3 Consideration of Demographics in Risk Assessment

Comment 2.3.1: Commenter 28 commends the EPA for considering environmental justice (EJ) issues in this proposal, with a focus on populations within a three

- mile radius of

facilities. Howeve r, the commenter suggests the EPA rule writers work with the EPA’s Office of Environmental Justice to develop specific criteria and guidance on how to interpret and apply the outcomes of EJ analyses in the rulemaking process and that the EPA update the pov erty statistics used in the analyses to include 2010 census data. Response 2.3.1: We note that we are working with the Office of Environmental Justice in an ongoing effort to develop new tools for considering environmental justice in rulemakings.

While we intend to use the 2010 census data in future analyses, we do not believe that a rerun of our analysis using the 2010 census data would yield results that would change our overall conclusions regarding EJ impacts. Therefore, we have decided not to rerun the EJ analysis using

the 2010 Census data.

Comment 2.3.2: Commenter 49 states that CAA section 112(f)( 2)(A) expressly instructs the EPA to impose additional emissions controls if needed to provide an ample margin of safety to protect public health. The commenter says that the term “public health” cannot reasonably be interpreted to include consideration of environmental justice in the context of section 112(f), and therefore the EPA’s proposal to consider demographic analyses in conducting risk reviews is not a proper exercise of the EPA’s authority. Although “public health” is not defined in section 112

or in the EPA’s 40 CFR Part 63 regulations, the Supreme Court observed in the context of the EPA’s NAAQS Program that the primary definition of the term should be applied, and that is public health means “the health of the public.” In the NAAQS program, the EPA interprets the term “public health” to include consideration of impacts on the population as a whole but also20

considers sensitive subpopulations identified by their health

- based sensitivities, recognizing that the objective is to protect the group rath er than any particular individual in the group. These sensitive subpopulations are identified independent of their demographic classifications. The commenter says that the EPA’s proposal to introduce demographic analyses to the determination of acceptable risk suggests that risk to some individuals is deemed more acceptable than risk to other individuals, and the commenter asserts that this type of political judgment has no place in a scientific evaluation of risk to public health. Response 2.3.2: In this rulemaking, the EPA developed comparative analyses of the demographics of the populations within the vicinity of the facilities in these source categories as part of the risk assessment for each source category; the analyses did not change the results or

c onclusions in the assessments. As stated in the Benzene NESHAP, in determining the need for residual risk standards, we strive to limit to no higher than approximately 1

- in

- 10 thousand (100

- in

- 1 million) the estimated cancer risk that a person living near a plant would have if he or she were exposed to the maximum pollutant concentrations for 70 years and, in the ample of safety decision, to protect the greatest number of persons possible to an individual lifetime risk level of no higher than approximately 1

- in

- 1 million. These considerations are made for all people regardless of racial or socioeconomic status. However, in determining whether to require additional standards under section 112(f), these levels are not considered rigid lines, and we weigh the c ancer risk values with a series of other health measures and factors in both the decision regarding risk acceptability and in the ample margin of safety determination. We also consider cost of controls in the ample margin of safety determination. While we analyzed the demographic makeup of the populations surrounding the facilities within source categories addressed by this rule making, we ultimately concluded that the risks from each source category were acceptable and protected public health with an ample margin of safety. Thus, the results of our demographic analyses only served to provide information about the demographic makeup of the populations near facilities in each of these source categories, but did not drive regulatory outcomes. Therefore, commen ter 49’s objections are moot.

Comment 2.3.3: Commenter 51 states that the EPA should assess the starting point or baseline health status of affected individuals or communities in addition to looking at the demographic census data as part of its socioecono mic analysis. The commenter also states that the EPA should follow the recommendations presented in the Environmental Justice Strategic Enforcement Assessment Tool (EJSEAT) by including other relevant EJ factors such as an assessment of the percent of popu lation with limited English proficiency, infant mortality, and low birth weight births. The commenter further states that the EPA must actually use the data from this analysis in its decision

- making process. The commenter urges the EPA to provide a plain

- l anguage statement of risks and benefits of the EPA’s final action to local communities for this and future actions in a way that lets them understand the levels of risk and what the EPA has determined is “acceptable” and “unacceptable” and what standard is required to provide an ample margin of safety. Response 2.3.3: We are not able to determine the baseline health status of individuals or communities in a national rulemaking. Individual privacy issues as they relate to health records

and the costs that wo uld be associated with such an analysis make the analysis infeasible. Through the EPA’s interim guidance on EJ and the Action Development Process, the agency is encouraging rule writers and policy makers to look at the whole range of factors that impact

co mmunities and population groups when crafting rules. The EPA is continuing to discuss and21

pilot approaches that are consistent with the agency’s responsibilities regarding EJ as outlined in EO 12898. In determining the need for tighter residual risk standa rds, the EPA strives to limit to no higher than 100

- in

- 1 million the estimated cancer risk for persons living near a plant if exposure to the maximum pollutant concentration for 70 years and to protect the greatest number of persons to a individual lifetim e risk of no higher than 1

- in

- 1 million. Considerations are made for all people regardless of racial or socioeconomic status. With respect to the EJScreen tool (referred to as “EJSEAT” by the commenter), it is premature to determine whether it should be us ed in future demographic analyses after it becomes finalized. The EJScreen is currently a draft tool in development. Thus, it has not yet undergone a sufficient level of peer review to determine whether to incorporate it into our analyses, and it is quite possible that the finalized EJSEAT tool will be different than the draft tool that exists today. It is the EPA’s goal to present all rule preambles and risk assessments in plain language, and we believe we have done so as much as possible. However, as futu re assessments are written we will consider the points raised in the comments provided above, and to the extent possible, incorporate those we believe will make our risk and rulemaking documents more informative.



### 2.4 Additional Standards to Address Risks

Comment 2.4.1: Commenter 51 states that the EPA failed to justify relying on the presumption of 100

- in

- 1 million as the benchmark for cancer risk acceptability, rather than ensuring a greater reduction of cancer risk. The commenter believes that the EPA mu st update and reduce its presumption that 100

- in

- 1 million lifetime cancer risk is acceptable based on new circumstances and evolving values since the 1980s. The commenter states that the EPA has both full authority and a responsibility to update its appro ach and reduce the presumptive level of what cancer risk is acceptable under section 112(f)(2). The commenter states that in setting this presumption of acceptable risk, the EPA recognized that it could not easily compare the risk from hazardous air pollut ion with the risk from other activities studied because of numerous differences. Specifically, the EPA stated that the consideration of the acceptability of a specific level of risk depends on factors including, but not limited to: the certainty and severi ty of the risk, the reversibility of the health effect, the knowledge or familiarity of the risk, and whether the risk is voluntarily accepted or involuntarily imposed. The commenter states that significant new information has been discovered and major cir cumstances have changed that should affect

how the EPA applies these factors to a source category in a rulemaking today. The commenter states that during the more than two decades since the EPA established that presumption,

dramatic scientific and societal advances have occurred that the EPA must take into account in its risk analysis. Response 2.4.1: In 1990, Congress codified in section 112(f) of the CAA the approach we use for our residual risk analyses (i.e., the Benzene NESHAP, 54 FR 38044). Under that approach, there is no single bright line (e.g., a 100

- in

- 1 million cancer risk) that indicates that risk is “acceptable.” Rather, multiple health metrics, including the cancer risk, are considered to determine whether the risk is acceptable. Where we conc lude that the risk is not acceptable, we cannot consider costs in requiring controls to bring risks down to an acceptable level. However, the analysis of whether risk is acceptable is not the endpoint. Once we determine that the existing MACT standards or identify what additional controls are sufficient to ensure risk is acceptable, we again review the health metrics in conjunction with considering the costs of22

controls to determine whether further additional controls should be required to provide an ample margin of safety to protect public health. The commenter does not provide support for its contention that “the risk that was acceptable in the world of the 1980s is no longer acceptable in today’s world.” Nor does the commenter explain how science has evol ved in a way that would undermine the codified framework for determining acceptability.

Comment 2.4.2: Commenter 51 states that more stringent standards are required in order to satisfy section 112(f)(2) because the residual risk assessments are incomplet e and underestimate risks, the determinations that risks are acceptable are incomplete and arbitrary, the EPA fails to provide an ample margin of safety to protect public health, and the EPA failed to provide adequate determinations of the environmental ef fects. Commenter 51 questions why, considering the statutory “aspirational goal” of achieving

lifetime cancer risks below 1

- in

- 1 million, the EPA is not requiring further emissions reduction to reduce risks to this level for these source categories. The c ommenter states that the acute risks should be found to be unacceptable because the risks were found to be above the EPA thresholds, did not consider combined effects of pollutants, were not based on MACT

- allowable emissions, and did not include facility

- w ide information. The commenter also states that the

chronic non

- cancer risks should be found to be unacceptable because the assessment did not consider greater risks to children, cumulative impacts, and possible underestimates in the TOSHI levels, in which impacts above the critical dose may not have been included in the TOSHI

calculations. The commenter also noted that staff recommendations in a 2002 internal EPA memo suggested the default HI limit be 0.2 rather than 1.0 to account for multiple sources of HAP emissions and stated that the EPA should reduce the TOSHI presumptive acceptability threshold to this level. The commenter states that the EPA also failed to explain why multipathway risks are acceptable when risks are above the presumptive thresholds for certain source categories and states that the EPA must require further reductions in multipathway risks to achieve acceptable levels. The commenter further states that the EPA has failed to demonstrate that risks from these source categories are accept able because it did not perform a risk assessment to include past and background emissions or the cumulative impacts from the different types of health risks and HAP. The commenter states that the EPA should find risk unacceptable due to socioeconomic disp arity in health risks. Response 2.4.2: We note that in 1990 Congress codified in section 112(f) (2)(B) of the CAA the approach we use for our residual risk analyses. Under that approach, there is no single bright line (e.g., 100

- in

- 1 million cancer risk) t hat indicates that risk is “acceptable.” Rather, multiple health metrics, including the cancer risk, are considered to determine whether the risk is acceptable. Where we conclude that the risk is not acceptable, we cannot and do not consider costs in requi ring controls to bring risks down to an acceptable level. However, the analysis of whether risk is acceptable is not the endpoint. Once we determine that the existing MACT standards are sufficient to ensure that risk is acceptable, we again review the heal th metrics in conjunction with the costs of controls, technical feasibility, and other relevant factors, to determine whether additional controls should be required to provide an ample margin of safety. The EPA disagrees with the commenter’s notion that an y TOSHI value greater than 0.2 should be considered unacceptable. We note that pollutant

- specific RfCs are not absolute thresholds, but estimates of chronic inhalation exposures at or below which health effects would not be expected to occur after a lifeti me of exposure, including in sensitive subgroups. We further note that these RfCs are developed using a health

- protective approach (see uncertainty23

discussion in section 4.2 of the Draft Residual Risk Assessment for 7 Source Categories (Docket

Item No. EPA

- HQ

- OAR

- 2011

- 0435

- 0018) ), and that TOSHI values of 1 or less are generally considered to carry no appreciable risk of adverse health effects and that there is generally no need to compound this protection by suggesting that any source category maximum TOSH I value would need to be at or below 0.2 before we would consider it to be acceptable. Finally we note that the commenter’s source for its statement that default limits HI should or must be establish at 0.2 rest on an internal EPA staff memo (from 2002) wh ich was never adopted as agency policy (and never reviewed by the public or by any peer review body) and consequently carries no precedential weight. Regarding the acute health risks, as described in the final Residual Risk Assessment for 7 Source Categori es ( available in the docket for this action), we do not sum results of the acute noncancer inhalation screen because of its conservative nature and the variable nature of emissions and potential exposures. The use of allowable emissions is also not conside red due to the conservative assumptions used to gauge worst

- case potential acute health effects. The conservative estimates built in to the screen include: 1) worst

- case meteorology (from one year of local meteorology); 2) that a person is located downwind at the point of maximum impact during this same 1

- hour period; and 3) that all emission points have their peak emission rates occur simultaneously. Thus, we believe performing an acute screen based on allowable emissions would be overly conservative and a t best, of questionable utility to decision makers. We do not perform a facility

- wide assessment for acute risks. The emissions included in a facility

- wide assessment have generally not been subjected to the same level of engineering

review as the source c ategory emission estimates and are likely to be less certain than our emissions estimates for the source category. That, combined with the already conservative nature of the acute assessment, would lead us to not conduct an acute risk assessment using faci lity

- wide emissions. We believe that further reductions based on multipathway risk are unnecessary for these source categories. Please see Response 2.1.14 for further discussion. See Response 2.1.6 concerning the commenter’s assertion that the assessment d id not consider greater risks to

children. The EPA disagrees with the comments that we did not consider aggregate or cumulative risks. As discussed in the risk document for this rule, 7 the assessments we conducted for the source categories consider the cum ulative cancer risks from all carcinogens and the cumulative

non

- cancer hazard indices from all non

- carcinogens (affecting the same target organ system) emitted from sources within the source category and also collocated sources at the same facilities. How ever, the commenter is correct that the assessments did not include background risks or contributions to risk from sources outside the facilities. Section 112(f)(2) of the CAA expressly preserves our use of the two

- step process for developing standards to address residual risk and interpret “acceptable risk” and “ample margin of safety” as developed in the Benzene NESHAP. 8 In the Benzene NESHAP, the EPA rejected approaches that would have mandated consideration of background levels of pollution

7 See U.S. EPA’s Residual Risk Assessment for 7 Source Categories in the docket for the Group IV Polymers and Resins, Pesticide Active Ingredient Production, and Polyethe r Polyols Production rulemaking.

8 National Emission Standards for Hazardous Air Pollutants: Benzene Emissions from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By

- Product Recovery

Plants (54 FR 38044, September 14, 1989) (Benzene NESHAP).24

in assessing the acceptability of risk, concluding that “...comparison of acceptable risk should not be associated with levels in polluted urban air. With respect to considering other sources of risk from benzene exposure and determining the acceptable risk level for al l exposures to benzene, EPA considers this inappropriate because only the risk associated with the emissions under consideration are relevant to the regulation being established and, consequently, the decision being made.” (54 FR 38044, 38061, September 14 , 1989). Although not appropriate for consideration in the determination of acceptable risk, we note that background risks or contributions to risk from sources outside the facilities under review could be one of the relevant factors considered in the amp le margin of safety determination, along with cost and economic factors, technological feasibility, and other factors. Background risks and contributions to risk from sources outside the facilities under review were not considered in the ample margin of sa fety determination for this source category, mainly because of the significant uncertainties associated with emissions estimates for such sources. Our approach here is consistent with the approach we took regarding this issue in the HON RTR, which the cour t upheld in the face of claims that the EPA had not adequately considered background. With regards to the comment concerning unacceptability due to socioeconomic disparity, under EO 12898, the EPA is directed to the greatest extent practicable and permitte d by law, to make EJ part of its mission by identifying and addressing, as appropriate, disproportionately high and adverse human health or environmental effects of its programs, policies and activities on minority populations and low

- income populations in the United States. Consistent with EO 12898 and the Presidential Memorandum that accompanies it, the EPA’s EJ policies promote EJ by focusing attention and EPA efforts on addressing the types of environmental harms and risks that are prevalent among minor ity, low

- income and indigenous populations. EO 12898 and the EPA’s EJ policies do not mandate particular outcomes from an action, but they demand that decisions involving the action be informed by a consideration of EJ issues. With respect to this rule, th e EPA found the overall level of risk from the source categories to be acceptable and to provide an ample margin of safety for all populations in close proximity to these sources, including minority and low

- income populations.

Comment 2.4.3: Commenter 51 states that the EPA’s AMOS analysis appears to be completely based on cost rather than on protecting public health. The commenter states that the EPA may not lawfully consider cost in deciding what the “ample margin of safety to protect public health” is b ut may only consider cost in determining whether additional standards are needed to prevent an adverse environmental effect. The commenter notes that the D.C. Circuit previously allowed the EPA to consider costs in the HON decision, but states that this ca se was wrongly decided, and the EPA should not rely on it to evade the CAA. The commenter also states that the EPA does not discuss how the health risk information shows an AMOS is provided by the proposed rule or explain what the ample margin is. The comm enter states that the EPA’s

determination that additional standards are not cost

- effective is irrational and unsupported. The commenter states that the EPA appears to simply conclude with no explanation that the cost numbers are not reasonable, even though some are only $5/lb. Response 2.4.3: The EPA disagrees with the commenter that the HON decision was wrongly decided and that the EPA relies on this decision to evade the CAA. As stated previously, ample margin of safety determinations for this rule are co nducted separately after determining whether risks are acceptable after implementation of the MACT standards, in accord with the25

two

- step framework set forth in the Benzene NESHAP. Using that framework, after determining that residual risks were already ac ceptable under the MACT standards, we considered costs,

cost

- effectiveness, technological feasibility, and other factors as set out in the Benzene NESHAP, at proposal we did not identify any additional controls beyond those that already ensure that

risks a re acceptable that would be needed to ensure an ample margin of safety. The EPA disagrees with the commenter that we cannot consider costs in the ample margin of safety determination step, as the D.C. Circuit squarely rejected the commenter’s position.

In accordance with the approach established in the Benzene NESHAP, we weighed all health risk measures and information considered in the risk acceptability determination, along with the costs and economic impacts of emissions controls, technological feasibili ty, uncertainties and other relevant factors in making the ample margin of safety determination for the source categories addressed by this rule making. The cancer and noncancer risk, number of persons at or above 1

- in

- 1 million, and the annual cancer case s per year were presented in the proposal preamble for every source category addressed by this rule. With regards to the $5/lb cost identified by the commenter, the EPA found only one control option in the proposed rule that fell in this range ($11,000/ton ), which was the beyond

- the

- floor option for equipment leaks from the P&R IV MACT equipment leak standards that apply to the p olyethylene terephthalate (PET) continuous thermal polyaspartic acid (TPA) high viscosity multiple end finisher subcategory. Howev er, this option was part of the MACT floor determination for this emission point, not part of the ample margin of safety step. All of the options identified in the ample margin of safety step for these source categories had cost effectiveness values much g reater than the value identified by the commenter ($244,000/ton), which the EPA stated as not being reasonable, given the level of emissions and risk reduction.

Comment 2.4.4: Commenter 51 states that the EPA did not fulfill its duty to consider

whether a more stringent limit is needed to protect the environment and may not base its

environmental determination on the human health risk assessment alone. The commenter states that the EPA must perform an appropriate ecological assessment. The commenter also notes that the EPA does not appear to have engaged in an Endangered Species Act consultation. Response 2.4.4: The EPA has developed a screening approach to examine the potential for adverse environmental effects as required under section 112(f)(2)(A) of th e CAA. The environmental screen focuses on the following seven environmental HAP:

 Five persistent bioaccumulative HAP (PB

- HAP)

– cadmium, dioxins/furans, polycyclic organic matter (POM), mercury (both inorganic mercury and methyl mercury), and lead.

 Two a cid gases

- hydrogen chloride (HCl) and hydrogen fluoride (HF). HAP that persist and bioaccumulate are of particular environmental concern because they accumulate in the soil, sediment, and water. The acid gases, HCl and HF, were included

due to their wel l

- documented potential to cause direct damage to terrestrial plants. For additional details on the environmental screening methodology, see the final residual risk document for this rulemaking. We conducted an environmental risk screening assessment for al l of the source categories addressed in this rulemaking. Of the 7 source categories addressed in this rulemaking, the PAI source category was the only one that had emissions of the environmental

HAP listed above.26

The PAI source category includes emissions of the environmental HAP HCl and HF. For HF and HCl, the average modeled concentration around each facility (i.e., the average concentration of all off

- site data points in the modeling domain) did not exceed the ecological benchmarks. In addition, each ind ividual modeled concentration of hydrogen chloride and hydrogen fluoride (i.e., each off

- site data point in the modeling domain) was below the ecological benchmarks for all facilities. For additional information on the environmental screening results, see the final residual risk document for this rulemaking. Based on our environmental screening analysis, we do not expect adverse environmental effects, as defined in CAA section 112 (a)(7), as a result of HAP emissions from any of the source categories addres sed in this rulemaking. The EPA does not have information, nor did the commenter provide information to support the position that emissions from the source categories addressed in this rulemaking would result in environmental effects. Because our analyses do not indicate an environmental effect from these source categories, we disagree with the commenter’s statement that the EPA must engage in consultations (e.g., with the U.S. Fish & Wildlife Service and the National Marine Fisheries Service) under 16 U.S. C. 1536(a)(2).



## 3.0 Technology Review Assessment and Standards

Readers are referred to section VI of the final rule preamble for this action for additional comments, and the EPA’s responses to those comments, on the technology review assessment.

Comment 3 .1: Commenter 51 asserts that to satisfy section 112(d)(6), the EPA must

recalculate the MACT floors without consideration of costs and re

- examine beyond the floor options today based on currently achievable emission levels. The commenter states that secti on 112(d)(6) serves as an ongoing ratchet to continually require the EPA to update standards to keep pace with new technology in order to decrease emissions. The commenter asserts that the EPA cannot ignore improvements in technology based solely on costs and must require the maximum

achievable level of control. Response 3.1: The commenter is incorrect as a matter of law. Section 112(d)(6) requires the EPA to “review, and revise as necessary (taking into account developments in practices, processes, and con trol technologies), emission standards promulgated under this section no less often than every 8 years.” As the EPA has explained on several prior occasions, section 112(d)(6) does not require MACT standards to be recalculated. See 70 FR at 20008 (April 1 5, 2005); NRDC v. EPA, 529 F. 3d at 1084. The EPA is not reopening that issue here, or otherwise reconsidering its interpretation of section 112(d)(6). Moreover, the argument that the EPA must recalculate floors in conducting a 112(d)(6) review was rejecte d by the D.C. Circuit in the HON opinion. See 529 F. 3d at 1084 (“It is argued that the EPA was obliged to completely recalculate the maximum achievable control technology

- in other words, to start from scratch. We do not think the words ‘review, and revise as necessary’ can be construed reasonably as imposing any such obligation.”). Accordingly, we did not, as the commenter requests, re

- calculate the MACT floors as part of our section 112(d)(6) review. Further, whether or not section 112(d)(6) is “technolo gy forcing”, the EPA retains very significant discretion in balancing relevant factors in determining whether it is “necessary” to revise the existing technology

- based MACT standards. See, e.g., Sierra Club v. EPA , 325 F. 3d 374, 378 (D.C. Cir. 2003) (unde r CAA section 202(l)(2), EPA is to consider factors beyond pure27

technological capability, and the statute does not direct how EPA should weigh such factors). In reviewing section 112(d)(2) standards, and determining whether to revise them is “necessary”

un der section 112(d)(6), the EPA may take into consideration cost and feasibility when evaluating developments in practices, processes, and control technologies.

Comment 3.2: Commenter 29 suggests that the EPA revise subparts JJJ, MMM, and PPP

to include th e vapor balancing option in the proposed Uniform Standards for Storage Vessel and Transfer Operations (proposed 40 CFR part 65, subpart I). This option allows offsite facilities that clean and/or reload transport vehicles and barges to control emissions fr om a fixed roof atmospheric storage vessel by using vapor balancing. The commenter provided suggested rule language to incorporate this change for subparts MMM, PPP, and JJJ. The commenter also suggests the EPA revise subparts JJJ, MMM, and PPP to include the definition of “repair” as it is defined in the proposed Uniform Standards for Equipment Leaks (proposed 40 CFR part 65, subpart J), which is based on the detection method used to identify the leak or potential leak. Response 3.2: While we appreciate th ese suggestions, these rule revisions were not included in the proposed rules, and we are not prepared to make these changes without providing an additional notice and opportunity for public comment, in part because we have not yet taken final action regar ding the proposed Uniform Standards provisions the commenter supports to conclude that they are generally appropriate. Therefore, we are not adding these provisions to the final rules at this time.

Comment 3.3 : Commenter 57 submitted a supplemental late comment to other on

- time comments and attachments (comments 51

- 56) that they provided on the proposed rule. The commenter urges the EPA to consider its recent consent decree with Marathon Petroleum Company, LP ( Marathon ) when setting standards for the PAI, PEPO, and P&R IV source categories. The commenter reports that the consent decree was filed in the U.S. District Court after the close of the comment period for the proposed rule and establishes requirements for emissions monitoring and reporting for Mara thon’s covered flares.

Commenter 57 states that in their on

- time comments on the proposed rule, they requested that the EPA require facilities to develop flare minimization plans, conduct root cause analyses of flaring events, and improve flare monitoring by requiring technology such as gas chromatography and laser sensing and urges the EPA to consider consent decrees that the EPA has entered into in recent years. The commenter asserts that the requirements (which they list in their comment letter) that th e EPA established under the consent decree with Marathon (included as an attachment with the comment letter) would reduce HAP emissions from Marathon’s flares by 140 tons per year (tpy) and reduce VOC emissions by 5,250 tpy. The commenter states that

the c onsent decree highlighted Marathon’s investment in making changes to decrease emissions from its chemical flares and that the changes made will “save” the facility $5 million a year by reduction steam usage and increasing product recovery.

Commenter 57 opines that the EPA must consider its April 2012 consent decree with Marathon as part of the PAI, PEPO, and P&R IV rulemaking. The commenter asserts that the decree demonstrates that there have been “developments” in the control of emissions from a

similar source category that the EPA cannot ignore under CAA section 112(d)(6) and that, given the potential for large emissions reductions, the EPA must consider under CAA section 112(f)(2) whether such requirements would provide an “ample margin of safety to pr otect public health” for the subject source categories.2 8

Response 3.3 : First, we note that we are not required to consider or respond to the commenter’s suggestions in its late

- submitted comments. However, to the extent allowed in the remaining time for pro mulgation of this final rule, we chose to review the commenter’s suggestions, and offer preliminary responses here in advance of any possible future regulatory undertaking that could be explored based on additional gathered data, which we do not currently have. The EPA is not at this time making changes to the flare provisions for the source categories addressed in this action. The commenter submitted their supplemental comment on June 21, 2012, which was well after the public comment period ended (March 30 , 2012). It is likely that, rather than to take commenter 57’s suggestion to simply adopt new flare requirements in the final rule, we would need to undertake another round of proposed rulemaking and solicit comment on any amendments to the flare provision s for these NESHAP, in order to meet our procedural obligations under CAA section 307(d). In other contexts outside of this rulemaking, the EPA has recently begun studying the performance of flares to control HAP emissions, as governed by the EPA’s Genera l Provisions at 40 CFR 63.11(b). In April 2012, the EPA conducted an external peer review of a draft technical report, Parameters for Properly Designed and Operated Flares ( http://www.e

pa.gov/ttn/atw/flare/2012flaretechreport.pdf ). In this report, the EPA evaluated test data and identified a variety of parameters that may affect flare performance and that could be monitored to help assure good combustion efficiency. Based on feedback rec eived from the

external ad

- hoc peer review panel, the EPA has since undertaken an initiative to go back and re

evaluate parameters that may affect overall flare performance at source categories known to use flares for controlling HAP emissions (e.g., petro leum refining). Currently, PAI, PEPO, and P&R IV sources may choose to use a flare to reduce emissions from storage vessels and process vents to comply with the MACT standards, but are not required to do so. Our records indicate the use of flares in only the PAI and P&R IV source categories, though it may be possible that flares may also be in use in the PEPO source categories (e.g., as a back

- up control device). However, we do not yet have sufficient flare performance data for the PAI, PEPO, and P&R IV so urce categories. Therefore, we are not at this time prepared to finalize any changes to the currently applicable regulations pertaining to the performance of flares in the PAI, PEPO, and P&R IV source categories, but we may explore whether to revise flare requirements in the future, if we conclude that new requirements are warranted and would be applicable to subject source categories. It is important to note that some of the requirements and parameters set forth in the Marathon consent decree (though

appro priate for the Marathon facility) might not be able to be applied universally to other source categories based on the differing vent gases that are being flared. Therefore, we are not prepared at this time to conclude either that the flare requirements imp osed in the Marathon consent decree in fact represent developments in processes, practices and control technologies for the PAI, PEPO, and P&R IV source categories, such that it is necessary to determine whether to establish such requirements under CAA sec tion 112(d)(6). Additionally, regarding the commenter’s claim that adding flare requirements would be necessary under section 112(f)(2) of the CAA in order to protect public health with an ample margin of safety, the EPA has already determined, based on ri sk assessments conducted for the subject source categories, that additional control to achieve an “ample margin of safety” for the PAI, PEPO, and P&R IV source categories is not needed, as the previously promulgated MACT standards already achieve the level of protection required by section 112(f)(2). See Docket ID

No. EPA

- HQ

- OAR

- 2011

- 0435 for documentation of the risk assessments.29



## 4.0 Startup, Shutdown, and Malfunction Exemption/Affirmative

Defense Provisions

4.1 Startup, Shutdown, and Malfunction Exemptio n

Readers are referred to section VI of the final rule preamble for this action for additional comments, and the EPA’s responses to those comments, regarding comments received on removal of the startup, shutdown, and malfunction (SSM) exemption.

Comment 4 .1.1: Commenters 38 and 41 note a control scenario currently used at one facility for periods of SSM would not be available with the removal of the SSM plan provisions. The commenters explain that one of commenter 38’s facilities has the capability to cont rol emissions through a backup system. When using the backup system, the control devices for one unit controls emissions from two units. When this scenario is used, the process parameters can vary significantly from steady state conditions and some emissio ns may be routed to a secondary vent for pressure control. The emissions released during these events are estimated and reported, the potential to emit from these activities has been established through performance testing, the emissions are limited by a n ew source review permit, and HAP emissions impacts have been found acceptable by the state air permitting agency. This commenter and commenter 41 request

this control scenario continue to be allowed. Response 4.1.1: We disagree that this control scenario can be allowed under the MACT standards. With the removal of the SSM exemption, facilities are now required to meet the MACT emission limits during all periods, including SSM. Any excess emissions will be considered a violation of the standard. The rule language proposed by the commenter would essentially amount to allowing a facility to temporarily bypass their emissions control device in a way that renders the emissions exempt from emission limits, which the EPA bel ieves would be inconsistent with the CAA’s requirement that emission limitations be continuously applicable. We acknowledge that process parameters may vary significantly from steady state conditions when transferring from one unit operation to another (as described by the commenter). The existing rule already includes flexible continuous process vent control compliance options. Current regulations not only allow owners or operators to comply by meeting a production based limit, but they are also allowed to comply by reducing emissions by 98 percent in a combustion device or to a concentration of 20 parts per million by volume (ppmv) on a dry basis (whichever is less stringent); combust the emissions in a boiler or process heater with a specified design heat input capacity or by introducing emissions into the flame zone; or combust emissions in a flare meeting specification requirements. If, however, none of these standards can be met, the affirmative defense to civil penalties provisions are available to sou rces experiencing a violation of the emission standards due to a malfunction.

Comment 4.1.2: Commenter 41 cites the EPA’s explanation of the difficulty of establishing emission standards for malfunctions due to the myriad of different types of

malfunction s that can occur, and asserts that a pressure relief device (PRD) release is unique in that the “release” is an inherent function of the device, and therefore a work practice standard

could be established.30

Response 4.1.2: We disagree with the commenter. Th e releases are related to process upsets or other malfunctions that require the release of pressure to avoid damage to equipment and to prevent harm to personnel at the facility. Such releases are not routine, are unpredictable in nature, and are considere d to be caused by malfunctions (e.g., poor design, improper maintenance, or operational error) that do not justify an exemption from standards that, under the CAA, apply continuously. The commenter failed to establish that the criteria for setting a work p ractice had been met, and as we explained in the preamble, it is impracticable to establish work practices or other alternative standards to manage these events and CAA section 112 does not require that we do so.

Comment 4.1.3: Commenter 44 states that th e proposal to eliminate the SSM provisions in the proposed subparts is not based on an accurate reading of the decision of the D.C. Circuit in

Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir. 2008). The commenter states that the EPA’s proposal for the standard s to apply at all times is not consistent with Sierra Club v. EPA , as the court did not hold that the EPA is prohibited from setting separate standards for periods of SSM that are different than the emission limits during normal operations but held that th e standards for those periods must be developed according to the section 112(d) MACT process and must be proven to be achievable under section 112(d). The commenter adds that there is ample precedent for the EPA applying a different standard during SSM eve nts, and such a standard could include a design, equipment, work practice, or operational standard under section 112(h). The
commenter notes that the definitions of “emission limitation” and “emission standard” have included provisions to limit “quantity, rate, or concentration of emissions of air pollutants on a continuous basis” since 1977, and since that time the EPA has not required sources to meet NSPS emission limits under CAA section 111 established for normal operations during SSM

events. The commen ter adds that Congress enacted the “continuous basis” language in section 302(k) knowing the EPA’s emission standards under section 111 exempted SSM periods, and there is nothing in the legislative history of the 1977 or 1990 amendments to the CAA that

sug gests Congress intended to overturn that practice. The commenter noted that case law has affirmed the appropriateness of including special SSM provisions in standards issued under

section 111. Response 4.1.3: The EPA does not claim that the Sierra Club ca se or the CAA constrains its authority to prescribe different standards for periods of startup or shutdown or for periods of malfunction. However, as explained in the preamble to the proposed and final rules, the EPA has

determined that CAA section 112 doe s not require that emissions that occur during periods of malfunction be factored into development of section 112 standards. The EPA’s rationale for this view is explained in detail in the preamble as well. At proposal, we explained that the D.C. Court ha d recently vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 63.6(h)(1) that are part of the CAA section 112 General

Provisions. Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir. 2008) cert. denied , 130 S. Ct 1735 (2010). We further explained that, w hen incorporated into section 112(d) regulations for specific source categories, these two provisions exempt sources from the requirement to comply with otherwise applicable MACT standards during periods of SSM. We also explained that because

these source categories rely on the General Provisions for SSM provisions, we were proposing to set standards that apply at all times, including during malfunctions. The EPA does not claim

that the Sierra Club case constrains its authority to prescribe unique standards for SSM periods.31

Rather, the EPA’s view is that this decision calls into question the legality of source category

specific SSM exemptions in rules promulgated pursuant to section 112. Further, in Medical Waste Institute v. EPA

, 645 F. 3d 420, 425

- 27 (D.C. Cir. 2011), the D.C. Circuit Court held that the EPA may permissibly amend improper MACT determinations, including amendments to improperly promulgated floor determinations, using its authority under section 112(d)(2) and (3). The absence of standards for HAP emitted during SSM is not proper.

National Lime

, 233 F. 3d at 633

- 34; see also Medical Waste Institute

, 645 F. 3d at 426 (resetting MACT floor, based on post

- compliance data, permissible when the originally

- established floor was improperly established , and permissibility of the EPA’s action does not turn on whether the prior standard was remanded or vacated). Similarly, the D.C. Circuit Court’s December 9, 2011, decision in Portland Cement Ass’n v. EPA (D.C. Cir. No. 10

- 1358) confirms that the EPA

is n ot constrained by CAA section 112(d)(6), and it may reassess its standards more often, including revising existing floors if need be. The commenters are, thus, incorrect that CAA section 112(d)(6) provides the exclusive authority to address standards that apply during SSM events. Here, the EPA adopted no MACT standard at all for HAP emitted during SSM, an approach soundly rejected by the D.C. Circuit Court in National Lime

, 233 F. 3d at 633

- 34. Consequently, we have revised the standards so the emission lim its of the rule apply at all times, including during periods of SSM. Where appropriate, we have adjusted the compliance demonstration provisions for certain standards to address startup and shutdown periods. We have also provided the ability to assert an a ffirmative defense to civil penalties for violations of standards that result from malfunctions. We believe this approach reasonably accommodates the requirements of the CAA and the Court’s reasoning in Sierra Club

. The EPA disagrees with commenters’ sugge stion that the existence of an SSM exemption in rules implementing CAA section 111 in 1977 when Congress enacted the “continuous basis ” language in the definition of “emission standard” is evidence that Congress approved of that regulatory SSM exemption. C ommenters fail to cite legislative history or any other evidence supporting that Congress was aware or approved of that exemption and the Sierra Club decision makes clear that such exemptions are inconsistent with the Clean Air Act.

Comment 4.1.4: Comment er 44 states that the EPA offers little support for the assertion that it is reasonable to interpret section 112 as not requiring the EPA to account for malfunctions in setting emission standards. The commenter states that it does not make sense for the EP A to assert that malfunctions are part of normal operations but then exclude emissions from these parts of normal operations in the determination of the emission limits. The commenter states that due to the unplanned nature and variety of potential malfunc tions, it would be difficult if not impossible for the EPA to gather data and set an emission standard for periods of malfunction. Due to these difficulties, the commenter suggests that under the authority of CAA section 112(h), the EPA prescribe alternati ve design, equipment, work practice, or operational standards where it

is not feasible to set or enforce a numerical emission limit. The commenter adds that there are work practices that can be identified as being the best to minimize emissions during a

ma lfunction, and the EPA must acknowledge the fact that even the best

- performing sources experience malfunction events. Response 4.1.4: The EPA’s rationale for its approach to malfunctions is discussed in the preambles to the proposed rule and this final act ion. 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. Accounting for malfunctions would be difficult, if not32

impossible, given th e 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. Setting work pr actice standards under CAA section 112 for malfunctions

– as opposed to startup or shutdown periods

– presents the same issues as setting numerical emission limits given the varied nature of malfunctions. Please see Response 4.1.6 for further discussion.

Comment 4.1.5: Commenter 44 states that the EPA has not justified adding new “general duty” language to the standards and should delete the new provisions. The commenter also states that the EPA lacks the authority to replace the previous reference to the General Provisions with somewhat different language in the individual subparts because these changes are not being proposed under 112(d)(6) or 112(f). Response 4.1.5: The EPA disagrees that it lacks the authority to make the changes proposed. We have eliminated the SSM exemptions in these three NESHAP, consistent with

Sierra Club v. EPA . As noted previously, the EPA relies on the CAA and Sierra Club for the

elimination of the SSM exemption. The EPA is not limited to adopting such changes by CAA sections 112(d)(6) or (f)(2), but retains ongoing authority to revise its prior adopted section 112(d)(2) and (3)

- based standards whenever the agency identifies a flaw in such sta ndards that renders them insufficient to meet the requirements of section 112(d)(2). See Medical Waste

Institute v. EPA . The EPA explained in the proposal that we were adding language to this regulation to replace General Provision requirements that refere nce vacated SSM provisions (77 FR 1288, 1299, 1302). The General Provisions “general duty” language that was previously referenced by these NESHAP includes language that is no longer necessary or appropriate in light of the elimination of the SSM exemption , so the EPA has modified the general duty requirements that were contained in 40 CFR 63.6(e) and placed them, modified, in 40 CFR 63.1310(j)(4), 63.1360(e)(4), and 63.1420(h)(4). The revised general duty requirement language reflects the general duty to m inimize 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 promulgating does not include that language from 40 CFR 63.6(e)(1).

Comment 4.1.6: Commenter 3 0 states that the EPA fails to provide adequate justification of why emission standards that apply during normal periods should also apply to malfunctions when emissions during malfunctions were not considered in developing the standards. The

commenter sta

tes that CAA section 112 does not give the EPA the authority to replace MACT limits that consider the emission level achieved by the best performing sources, including periods where such sources experience malfunctions, with an affirmative defense to penal ties. Commenter 44 states that the affirmative defense provisions do not cure the EPA’s failure to set emission standards that are achievable during SSM events and are not a substitute for setting achievable emission standards for these periods.

Commenters 29, 30, and 41 believe the EPA should promulgate separate standards under CAA section 112(h)(1) for periods of malfunction. Commenter 29 suggests that the EPA establish a work practice for malfunctions that result in only small levels of excess HAP33

emissi ons, such as 10 pounds of HAP, which requires the owner/operator to stop the emissions, stop the malfunction, and return to normal operations as soon as possible. Response 4.1.6: The affirmative defense is not a replacement or alternative for a MACT limit and the EPA’s approach to malfunctions is not dependant on the affirmative defense. As we explained in the preamble to the proposed rule, 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, emission standards for new sources must be no less stringent than the level “achieved” by the bes t 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 a gency 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 emission standards

consistent with the CAA sec tion 112 case law, nothing in that case law requires the EPA to consider malfunctions as part of that analysis. CAA section 112 uses the concept of “best controlled” and “best performing” unit in defining the level of stringency that CAA section 112 perfo rmance 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. 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 ne cessary to solve a problem. We generally defer to an agency’s decision to proceed on the basis of imperfect scientific information, rather than to “invest the resources to conduct the perfect study.”). See also, Weyerhaeuser v. Costle

, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (“In the nature of things, no general limit, individual permit, or even any upset provision can anticipate all upset situations. After a certain point, the transgression of regulatory limits caused by ‘uncontrollable acts of third parties, ’ such as strikes, sabotage, operator intoxication or insanity, and a variety of other eventualities, must be a matter for the administrative exercise of case

- by

- case enforcement discretion, not for specification in advance by regulation.”). In addition, t he 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 non

- malfunctioning source. The EPA’s approach to malfunctions is consistent with CAA section 112, and is a reasonable interpretation of the statute.



### 4.2 Affirmative Defense Provisions

Comment 4.2.1: Commenter 51 urges the EPA not to adopt the affirmative defense provisions. The commenter states that the affirmative defense provisions are unlawful, and creates a new loophole that will reduce the deterrent impact of the proposed standards. The34

commenter argued that Congress plainly intended citi zens to be able to enforce emission standards under the CAA using the full range of civil enforcement mechanisms available to the government, and, in the HAP context, subject only to the limitation that government not be “diligently prosecuting” its own ci vil enforcement action, according to CAA section 304(b)(1)(B). The commenter further states that the EPA exceeded its authority by attempting to impose additional Agency

- created limits on civil penalties and that the proposed affirmative defense goes direc tly against Congressional intent that judges should determine the size of civil penalties whenever they are sought, and that the proposal will impermissibly chill citizen participation and the ability to win an effective, deterrent remedy in CAA enforcemen t actions. The commenter observed that the CAA gives the EPA minimal discretion that only applies to administrative penalties which may be imposed under subsection 113(d), but no authority to compromise, modify or limit civil penalties that a court may imp ose under section 113(e) or section 304. The commenter stated that it is improper for a court to fail to consider these factors, or to fail to make its own determination of what civil penalties are “appropriate” under CAA section 304(a), and EPA should not ask a court to ignore its legal duty . The commenter asserted that the burden the affirmative defense places on citizens makes it less likely that they will enforce the Act, that citizen participation in CAA enforcement will be hindered, in violation of citizens‘ rights to protect themselves from pollution and in direct conflict with congressional intent. The commenter stated that the affirmative defense imposes a technical burden on citizens, and the burden renders the defense impermissible. The commente r predicted that the affirmative defense would likely be used on a routine basis by polluters seeking to avoid penalties, just as the malfunction exemption was, and enforcement of the Act

could suffer.

The commenter also states that if the EPA had the auth ority to promulgate any affirmative defense to penalties for malfunction, it should also promulgate strong reporting, monitoring, and other compliance measures, require a specific monetary penalty for each malfunction, and require that the affirmative defe nse cannot be used by a specific facility or company more than once within a set period of time, such as 10 years. Response 4.2.1: For malfunctions, the EPA is finalizing the proposed affirmative defense language for violations of the standards that are ca used by malfunctions with minor revisions discussed elsewhere in this section. As the EPA explained in the preambles to the proposed rule and final rule, the EPA recognizes that even equipment that is properly designed and maintained can fail and that such failure can cause a violation of the relevant emission standard. The EPA is including an affirmative defense in the final rule as we have in other recent section 111, 112 and section 129 rules so as to balance the tension, inherent in many types of air re gulation, to ensure adequate compliance while simultaneously recognizing that despite the most diligent of efforts, emission limits may be exceeded 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) (emission limitat ions under CAA section 112 must both continuously apply and meet section 112’s minimum stringency requirements, even during periods of SSM). Thus, the EPA is required to ensure that section 112 emission limitations are continuous. The affirmative defense f or malfunction events meets this requirement by ensuring that even where there is a malfunction, the emission limitation is still enforceable through injunctive relief. While “continuous”35

limitations, on the one hand, are required, there is also case law i ndicating that in some 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 D.C. 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 ‘ne ver 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 calls into question the relevance of t hese 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 excess emissions that are proven to be beyond the control of the source. By incorporating an affirmative defense, the EPA has formalized its approach to upset events. In a Clean Water Act setting, the Ninth Circuit required this type of formalized approach when regulating “upsets beyond the control of the permit ho lder.” Marathon Oil Co. v. EPA

, 564 F.2d 1253, 1272

- 73 (9 th Cir. 1977). See also, Mont. Sulphur & Chem. Co. v. United States

EPA , 2012 U.S. App. LEXIS 1056 (Jan 19, 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 limitations are

“continuous” a s required by 42 U.S.C. § 7602(k), and account for unplanned upsets and thus support the reasonableness of the standard as a whole. Further, the EPA’s view is that the affirmative defense is consistent with CAA sections 113(e) and 304. Section 304 gives d istrict court’s jurisdiction “to apply appropriate civil penalties.” Section 113(e)(1) identifies the factors that the Administrator or a court shall take into consideration in determining the amount of a penalty to be assessed only after it has been

deter mined that a penalty is appropriate. The affirmative defense regulatory provision is not relevant to the amount of any penalty to be assessed under section 113(e) because if a court determines that the affirmative defense elements have been established, th en a penalty is not appropriate and penalty assessment pursuant to the section 113(e)(1) factors does not occur. The EPA’s view is that an affirmative defense to civil penalties for violations of applicable emission standards during periods of malfunction appropriately balances competing concerns. On the one hand, citizen enforcers are concerned about additional complications in their enforcement actions. On the other hand, industrial sources are concerned about being penalized for violations caused by malf unctions that could not have been prevented and were otherwise appropriately handled (as reflected in the affirmative defense criteria). The EPA is promulgating the affirmative defense applicable to malfunctions under the delegation of general regulatory a uthority set out in section 301(a)(1) of the Act, 42 U.S.C. § 7601(a)(1), in order to balance this tension between provisions of the Act and the practical reality, as case law recognizes, that technology sometimes fails. See generally Citizens to Save Spen cer County v. U. S. Environmental Protection Agency , 600 F.2d 844, 873 (D.C. Cir. 1979) (using section 301(a) authority to harmonize inconsistent guidelines related to the implementation of federal preconstruction review requirements). The EPA disagrees th at the affirmative defense provision will hamper citizen enforcement. First, injunctive relief is still available and the threat of penalties would not deter violations in cases where all of the conditions of the affirmative defense have been satisfied36

bec ause the affirmative defense criteria ensure that all reasonable steps were taken to prevent a malfunction that causes excess emissions. Further, litigating whether a source has met the affirmative defense will not burden citizen groups any more or less th an would litigating the appropriate penalty amount in the penalty assessment stage of a citizen suit enforcement action, because the section 113(e) penalty assessment criteria and the affirmative defense criteria are similar and in fact overlap. For exampl e, the requirement that the Administrator or the court consider “good faith efforts to comply” is bound to generate the type of fact

- intensive disputes that the commenter complains of. In addition, several of the affirmative defense criteria are exactly th e type of criteria the Administrator or Court might consider in determining whether a source made “good faith efforts to comply.” For example, to take advantage of the affirmative defense, the source must prove by a preponderance of the evidence that, amon g other things, the excess emissions “were caused by an unavoidable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner” and “could not have been prevented through careful planni ng, proper design or better operation and maintenance practices” and “did not stem from any activity or event that could have been foreseen and avoided, or planned for.” Thus, the EPA does not expect the affirmative defense provision to significantly alter the burden of bringing a citizen enforcement action. For those cases that do proceed to trial, even in the absence of this affirmative defense, sources generally raise equitable arguments to argue for a low penalty and citizens often rebut such arguments. Therefore, as a practical matter, the EPA does not expect the affirmative defense provision to materially affect the practice of CAA enforcement. The EPA is not adopting the commenter’s suggestion with respect to compensatory damages or limits on the freq uency of use of the affirmative defense. It is not clear that the EPA has authority to require the automatic imposition of compensatory damages, and even if such authority exists, the EPA does not think automatic imposition of damages is appropriate, as it would unduly complicate the enforcement process. Ensuring that malfunctions do not recur can be handled through imposition of appropriate injunctive relief. In addition, the EPA’s view is that it would not be appropriate to limit a source’s ability to tak e advantage of the affirmative defense to one time over a specified period of time such as 10 years, given that the affirmative defense is only available when the source could not have prevented the excess emissions. With respect to the commenter’s suggest ed reporting requirements, the reporting requirements in the rule being promulgated already require malfunction reporting, and the affirmative defense provisions require that parties choosing to assert the affirmative defense meet additional malfunction re

porting requirements. Any such reports submitted to the EPA are publicly available pursuant to CAA section 114.

Comment 4.2.2: Several commenters (29, 30, 31, 38, and 44) state that the affirmative defense provisions are overly burdensome and are not real istically attainable due to the specific language of the required criteria. The commenters request that the EPA clarify and redefine the criteria considering attainability. Commenter 31 suggests several modifications to the affirmative defense provisions. One suggestion is to rely on the phrase “preponderance of evidence,” as is used in paragraph (a) of these provisions but is later contradicted by the use of “any” and “all.” Another suggestion is to make the definition of malfunction match that of the Gene ral Provisions, where the phrase “not reasonably preventable” is used rather than the phrase “sudden, infrequent, and unavoidable failure.” Commenter 29 suggests revising the affirmative37

defense provisions to remove the reference to off

- shift and overtime labor because responding to malfunctions is many times a case

- by

- case situation and the use of overtime or off

- shift labor is only one consideration in how to address a malfunction. This commenter also suggests removing the requirement for contemporaneous operating logs because its facilities use electronic media to document actions, and a printed and signed log is an outdated mode of documentation. Commenter 44 requested that the term “infrequent,” and subjective phrases, such as “if at all possible,” be r emoved from the regulatory text, as these terms could be subject to different interpretations by regulatory agencies. Response 4.2.2: The EPA believes the affirmative defense criteria are well

- defined and will assist the EPA and the courts in making reason ed determinations as to the establishment of affirmative defenses. The EPA does not believe the terms and conditions of the affirmative defense are overly subjective, extreme or need further qualification. The EPA and the courts have expertise and experien ce in evaluating and applying criteria such as those for the affirmative defense. Many of the conditions in the affirmative defense are modeled after the affirmative defense in the EPA‘s state implementation plan (SIP) SSM policy, See, e.g., State Implemen tation Plans: Policy Regarding Excessive Emissions During Malfunctions, Startup, and Shutdown (Sept. 20, 1999). Other conditions are modeled after a Federal Implementation Plan promulgated by the EPA (40 CFR 50.1312) and recently affirmed by the U.S. Court of Appeals for the 9 th Circuit (

Montana Sulphur & Chemical Co. v EPA , _666 F.3d 1174 (9 th Cir. 2012). The EPA‘s view is that use of consistent terms in establishing affirmative defense regulations and policies across various CAA programs will promote cons istent implementation of those rules and policies. Several states have adopted the EPA‘s SIP SSM policy into their SIPs. We do not have any indication that parties to enforcement proceedings have had any significant difficulties applying the terms of these SIP affirmative defenses. The EPA notes, however, that the references to off

- shift and overtime labor have been removed from the final affirmative defense

criteria. With respect to the comment concerning operating logs, the EPA believes that log entries should be made contemporaneously, which does not mean, at the exact time that the engineers are taking actions to address the malfunction, but rather immediately thereafter. That way, more accurate records of the malfunction can be expected, as opposed to records reconstructed long after the malfunction. “Properly signed” means that the records should be signed by an engineer or other employee with knowledge of the situation, in a legible manner so that enforcement officials can tell who made the record and what their responsibilities were. The EPA generally accepts documents in electronic format, as long as the format is compatible with the requirements of the standards. For the affirmative defense provisions, the owner or operator of a facility experiencin g an exceedance of its emission limit(s) during a malfunction must notify the Administrator by telephone or fax transmission of the exceedance. However, the written reports are required to demonstrate that the affirmative defense provisions have been met. In the case of signed logs, the EPA accepts electronically signed operating logs, where the format and method of submission meets the regulatory criteria and are compatible with the EPA’s and the delegated authorities’ electronic submission systems. Any so urce submitting records electronically should exercise due diligence to assure receipt by the EPA and the delegated authority.

Comment 4.2.3: Commenter 31 is concerned that an affirmative defense implies that the facility is guilty until proven innocent a nd that the proposed language improperly puts the burden of proof on the facility rather than on the EPA. Commenter 30 also states that the affirmative38

defense criteria force an affected source to admit to a violation of the emission limit before the

EPA i nitiates an enforcement action without any assurance that it can successfully avail itself of the affirmative defense. Commenter 31 suggests that the EPA establish a rebuttable presumption rather than affirmative defense where it is presumed that the facil ity did everything in their power to minimize emissions during these events, unless the EPA proves certain facts that are enumerated in the rules. According to the commenter, this would allow the EPA to challenge the alleged deviation without compromising the legal rights of either party. Commenter 44 also is concerned that the affirmative defense provisions imply the facility is guilty until proven innocent and put the burden of proof on the facility rather than the EPA. This commenter states

that the EPA must modify the provisions substantially so that they do not require sources to prove their innocence. Response 4.2.3: The affirmative defense does not change the burden of proof with respect to establishing a violation. The burden of proof that a violatio n occurred remains with the plaintiff in an enforcement action. See, e.g., 40 CFR 22.24. If a violation has been established and a source wishes to assert the affirmative defense with respect to penalties, the source does bear the burden of establishing th at the elements of the affirmative defense have been met. This

burden

- shifting is appropriate because the source is in a better position to determine the facts required to establish the defense. See, e.g., Arizona Pub. Serv. Co. v. EPA , 562 F.3d 1116, 1120

, 1129

- 30 (10th Cir. 2009) (rejecting industry challenge to the EPA’s use of an affirmative defense to address excess emissions during malfunction events.). The EPA does not agree that the affirmative defense should operate as the commenter suggests. The c ommenter improperly seeks to shift the burden of proof regarding eligibility for the affirmative defense from the source to the party bringing the enforcement action. It is the source, not the EPA (or other party taking enforcement action) that has the inf ormation relevant to assess whether a particular event qualifies as a malfunction and meets the affirmative defense.

Comment 4.2.4: Commenters 29 and 31 suggest revisions or removal of the formal root cause analyses required by the affirmative defense pro visions. Commenters 31 and 38 suggest a formal root cause analysis should only be required when other reasonable methods fail to show the cause of a malfunction or when the serious nature of an event might make such an analysis necessary. Commenter 29 stat es that formal root cause analyses are not needed because malfunction events are already routinely investigated and formal root cause analyses will detract from candid inquiries into the events. Commenter 44 states that the root cause analysis requirement may make the affirmative defense unavailable if the source is not able to determine the primary cause of the malfunction. The commenters state that it should be expected that in many causes the primary cause will not be ascertainable or that it will not be possible to identify a way to ensure the malfunction will not recur. Response 4.2.4: The root cause analysis requirements specify that the purpose of the root cause analysis is “to determine, correct, and eliminate the primary cause of the malfunction.” While the root cause analysis itself does not necessarily assure that these purposes will be satisfied, in most cases, the EPA believes that a properly conducted root cause analysis will have such results. The EPA does not assume that all malfunctions requ ire an identical degree of investigation. The EPA expects that the effort required to do a root cause analysis will vary depending on the nature of the malfunction. The commenter does not explain the view that preparation of a root cause analysis would

det ract from candid inquires into the events, and the EPA sees no reason that requiring such an39

analysis to be prepared would do so. Indeed, the EPA has specified in consent decrees that root cause analyses be conducted and we have never had complaints from t he defendants saying that this detracts from candid inquires into the events.

Comment 4.2.5: Commenters 38, 41 and 44 state that the EPA estimate of $1,459 to assert an affirmative defense for a malfunction is not credible, appears entirely arbitrary, an d is remarkably low given the number of different demonstrations and root cause analysis that are required of a source. Commenters 38 and 41 estimate that the cost of a full root cause failure analysis is roughly $15,000 to $19,000, based on institutional knowledge, interviews of principle investigators, travel costs and other expected costs. The commenters note that the resources that will be needed to perform the root cause analyses will dilute the facilities’ ability to focus on the issues that pose the greatest risk. Commenters 38 and 41 opine that the burden imposed by the affirmative defense standards has been greatly underestimated by the EPA, and estimates that the cost is at least an order of magnitude greater than the EPA estimates. Response 4.2.5: As part of an affirmative defense, we are requiring that an owner or operator conduct a root cause analysis and submit it with their semiannual compliance report to the Administrator, as documentation of having met the conditions and requirements for asse rting an affirmative defense. The EPA believes it has provided clear criteria within the affirmative defense provisions to support the development of an affirmative defense report. The EPA believes that these provisions will result in a minor administrativ e burden, but will result in sources analyzing their violation emissions to reduce or avoid those emissions in the future, which is an environmental benefit. The purpose of the analysis is to identify, correct, and eliminate or reduce the probability of th e primary cause of the malfunction in order to prevent another from occurring. A root cause analysis is not mandatory and is only required if a source seeks to assert an affirmative defense. However, such an analysis is beneficial in resolving or preventin g violations and excess emissions whether the source seeks to assert the affirmative defense or not. A root cause analysis is one example of what constitutes good air pollution control practices to
minimize emissions. Owner operators will often employ such analyses as part of their normal operations,

because a ny regulatory noncompliance event may impact the safety of workers, the environment, and/or the continued operation of the plant. Therefore, these events typically are, or should be, investigated and r esolved by industry, whether or not their ultimate intention is to assert affirmative defense. While there may be a cost associated with conducting a root cause analysis, an owner or operator may eventually recoup the cost of the analysis by eliminating or reducing the likelihood of another similar failure. Avoiding such failures may increase the reliability of production, and avoid the cost of lost production time, material and equipment losses, and further compliance and safety violations. While we (and the commenters) acknowledge that the complexity of a malfunction event can vary, the EPA must disagree that the costs cited by the commenters represent the typical cost of an analysis. Our technical and managerial hour estimates may not be representative o f all potential expenditures that are not already incurred during normal operations, but our estimates were similar to a portion of the cost analyses submitted by commenters 38 and 41. Commenters 38 and 41’s analyses differed from ours by including expense s that, for any given event, may or may not be necessary. Our estimate is based on the assumption that the data gathering, recordkeeping and reporting that is already required by the applicable subparts will supply a portion of the information required for the analysis to support an assertion of affirmative40

defense. In addition, we anticipate that not all analyses will require contracted or off

- site technical support, an assumption supported by the same commenters. As such we consider our

estimate to be a r easonable estimate for the purpose of estimating the regulatory burden on affected sources for these rules.

Comment 4.2.6: Commenter 38 believes the EPA underestimates the number of events that would require a root cause analysis in the proposed rule. For instance, according to the commenter, a single PET production unit may have 150 PRDs, and at an estimated release rate of 0.5%, there would be roughly 2 events to evaluate every three years for a single facility just for

PRD releases. The commenter adds t hat a leaking PRD above the equipment leak threshold would add another leaking PRD per year to the total for a facility with 150 PRDs. Commenter 41 states that it collected data on PRD releases from 40 chemical production sites that collectively had 14,139 PRDs in service. The commenter reported that 181 releases from these PRDs were identified, for a release rate of a little over 1 percent. Response 4.2.6 The EPA recognizes that the number of events that would violate the prohibition of pressure releases t o the atmosphere that could lead to an owner or operator to conduct a root cause analysis can vary. By definition, malfunctions are unplanned/unpredictable events. The commenter implies that 2 events per facility for three years is a reasonable number

to a nticipate. Affected sources can and do operate for three years without malfunctions serious enough to trigger an emergency release of HAP to the atmosphere. The EPA notes that the data collected by the commenter regarding the number of PRDs and PRD release s from chemical production sites was comprised of facilities throughout the entire chemical sector, and not just the source categories addressed in this rulemaking, which would overestimate the number of PRDs/PRD releases for the source categories subject to this action. A pressure release is a release triggered by pressure that is greater than the maximum allowable working pressure of the PRD. The final rules prohibit pressure releases to the atmosphere from PRDs in organic HAP service, unless the PRD is r outed to a control device, process, or drain system. However, different PRD provisions/standards are applicable to leaks which may occur after a PRD has a pressure release because the seal does not reseat properly. The leaks referenced by the commenter are covered under the standard for leak detection and repair (LDAR). Under the LDAR standards, to ensure that the PRD is properly reseated, these rules require LDAR monitoring within 5 days of a PRD release. For all three source categories, the existing requi rements for PRDs already specify that the PRD must always be operated with no detectable emissions (i.e., 500 ppm above background).

Comment 4.2.7: Commenters 29, 31, and 44 suggest that the immediate notification requirements in the affirmative defense p rovisions be removed. The commenters added that if the notification requirement is kept, the EPA should allow electronic communication and recordkeeping. Commenters 29 and 30 state the immediate notification requirements are duplicative of requirements of SARA/CERCLA/EPCRA and many state regulations and will be burdensome for both facilities and agencies to review. Commenter 30 adds these requirements may report emissions not in exceedance of emission limits, it is not clear to whom the reports

would be sub mitted, and they should be replaced with a semi

- annual reporting requirement. In addition, Title V Operating Permit requirements include reporting of events in which emission

limits have been exceeded in semi

- annual deviation reports, and these reports can be used to supply information on the affirmative defense criteria. Commenter 44 requests that malfunction41

reporting be required on a semi

- annual basis to avoid problems with being able to submit a report within 45 days and potential issues with requesting and receiving an extension of the reporting deadline in a timely manner. In contrast, commenter 51 states that the EPA must promulgate specific public reporting and notification requirements for malfunctions and any exceedance that occurs. While the EPA proposes to require malfunction reporting within 2 days by telephone and a written report within 30 days if the facility intends to use an affirmative defense, the commenter states this reporting should be required regardless of whether a facility intends to use an affirmative defense, and the timing of the telephone call and report should actually be shorter. The commenter declares that the EPA must require the call within 24 hours and make a notice available publicly through the EPA’s website and through ECHO within 24 hours. The commenter also asserts that within 24 hours of receiving this notification, the EPA should provide this information to the appropriate EPA Regional Office and direct the Regional Office to notify the local community of the event

o n the Internet, direct communication, and through all available means. The commenter states that the EPA should further require the facility to provide notification to the community through an appropriate public forum, such as the company website, press re lease to the local newspaper, radio and TV news station, within 24 hours. The commenter further declares the written report should be required within 7 days and distributed to the public using the same distribution method

as the earlier notification and th at this report should include the nature of the event, the duration of the event, and estimate of emissions released during the event, and a description and time of correction actions taken and planned to be taken. Response 4.2.7 We agree with the first se t of commenters regarding the timing of some of the reporting requirements and have revised the reporting requirement for asserting an affirmative defense in 40 CFR 63.1310(k) of subpart JJJ, 63.1360(k) of subpart MMM, and 63.1420(i) of subpart PPP to remo ve the 2

- day notification requirement. We have revised these sections in the final rules to allow an owner or operator of the affected source seeking to assert an affirmative defense after experiencing a violation of its emission limit(s) or a violation of an emission standard during a malfunction to submit a written report to the Administrator in the first periodic compliance, deviation report or excess emission report otherwise required after the initial occurrence of the violation of the relevant standar d, unless such report is due less than 45 days after the violation, in which case the affirmative defense report could be included in the next such required report. We do not agree with the latter commenter that the suggested notification and reporting req uirements are necessary, as they would be duplicative of the immediate notification requirements of SARA/CERCLA/EPCRA, would be burdensome for both facilities and agencies to review, and would not enhance compliance beyond that of the existing requirements for reporting violations of emission limits. An affirmative defense to civil penalties for violations of emission limits that are caused by malfunctions is available to a source owner or operator if he can demonstrate that certain criteria and requirement s are satisfied. The criteria ensure that the affirmative defense is available only where the event that causes a violation of the emission limit meets the definition of malfunction in 40 CFR 63.2 (sudden, infrequent, not reasonably preventable and not cau sed by poor maintenance and or careless operation) and where the source owner or operator took all appropriate actions to minimize emissions. If a source is in compliance and does not encounter malfunctions that cause a violation of the standard, we do no t expect this activity to be routinely performed by a source owner or operator. The decision to meet the reporting and recordkeeping requirements rests with the42

source owner or operator, who must weigh the cost of meeting the requirements against his

perce ived need to prepare an affirmative defense.

Comment 4.2.8: Commenter 31 asserts that not allowing an affirmative defense in an action for injunctive relief is arbitrary and capricious. The commenter opines that the EPA

should allow facilities to assert an affirmative defense for the exceedance of an emission limit during malfunctions if the EPA seeks to enforce that emission limit through injunctive relief and suggested eliminating that exclusion from the affirmative defense provisions. The commenter

sta tes that the type of legal action sought should have no bearing on the availability of this defense, as the definition of malfunction does not change with the type of legal action the EPA

uses. Commenter 44 states that it is not clear what civil penalties the affirmative defense covers. The commenter believes the affirmative defense should apply to civil penalties, civil administrative penalties, noncompliance penalties, enforcement actions by the EPA, states, or

citizen

- suit plaintiffs, and injunctive reli ef. Response 4.2.8: In response to the commenter that states that it is not clear what civil penalties the affirmative defense covers, the affirmative defense applies to civil penalties, including civil administrative penalties and penalties under section 120, but does not apply to injunctive relief or criminal penalties. The affirmative defense is available in any civil action to enforce the standards set forth in these rules, whether such action is brought by the EPA , a state or local authority or a citi zen. The EPA does not intend to provide an affirmative defense to criminal charges as the very nature of criminal charges is that there is alleged to be a knowing violation (CAA Section 113(c)(1

- 3), or a knowing or negligence release that threatens imminen t danger to persons (CAA Section 113(c)(4)and (5)). In these circumstances, it is likely that the source did not do all that could be done to prevent the excess emissions. However, if there are circumstances that justify a knowing release, such circumstanc es can be raised in any enforcement action and may be the basis for a defense. In response to the comment that affirmative defense should be made available in an action for injunctive relief, in some cases injunctive relief may still be appropriate and necessary to remedy an existing violation and to bring a violating source into co mpliance. Therefore, we believe that it is not appropriate for our regulations to generally allow for an affirmative defense in cases of injunctive relief.

Comment 4.2.9: Commenter 44 believes the affirmative defense provisions should apply to the potenti al violation of emission limits during a startup or shutdown event as well as during malfunctions, if the EPA is to use such affirmative defense. Response 4.2.9: The EPA is promulgating the affirmative defense for malfunctions only, not for periods of startup and shutdown. The EPA believes that malfunction events should be treated differently than periods of startup and shutdown, which are predictable and routine aspects of a source’s operations. Because startup and shutdown periods are part of a source’s normal operations, the same approach to compliance with, and enforcement of, applicable emission standards during those periods should apply as otherwise applies during a source’s operations. Further, periods of startup and shutdown

-- but not malfunctions

-- are taken into account when establishing section 112 emission standards. For these reasons, the EPA does not believe it is appropriate to apply the affirmativ e defense provisions to startup and shutdown periods.43

Comment 4.2.10: Commenter 44 states that the EPA has not justified changing conditions that apply to performance testing. The commenter contends that where the proposed rule removed previously applicab le references to the NESHAP General Provisions that required performance tests to be conducted based on normal operating conditions of the affected source and specified that “operations during periods of startup, shutdown, and malfunction shall not

constit ute representative conditions for the purpose of a performance test,” the proposal would allow the EPA to direct a source to conduct performance testing during abnormal operations, such as startups, shutdown, or malfunctions. The commenter states that the EPA cannot “amend” existing MACT standards in a way that can make the standards more stringent without first providing an adequate justification for departing from the EPA’s previous judgment about the appropriate conditions for performance testing. Respon se 4.2.10: As noted by the commenter, we eliminated the SSM exemption as it applies to performance testing under 40 CFR 63.7(e)(1) and we specify that “[p]erformance tests shall be conducted under such conditions as the Administrator specifies to the owner or operator based on representative performance of the affected source for the period being tested” (at 40 CFR 63.1333(a), 63.1365(b), and 63.1437(a)). One of the reasons for this is because the General Provisions selectively apply to part 63 standards an d some part 63 standards establish alternative standards or compliance demonstration methods during startup and shutdown periods that may require performance testing during startup and shutdown periods. Sections 63.1333(a), 63.1365(b), and 63.1437(a) speci fy the conditions that performance testing must be conducted for the PAI, PEPO and P&R IV MACT standards. The final requirements do not allow for performance tests to be conducted during periods of malfunction, and the conditions for conducting performance testing for the existing MACT standards have not changed, with one exception. The final 40 CFR part 63, subpart JJJ amendments allow facilities to comply with an alternative compliance determination option to meet mass emissions per mass product limits

du ring startup and shutdown periods. In order to use this alternative compliance determination option, owners or operators would meet a mass emissions per mass product limit by either: (1) keeping records that establish the raw material feed rate and product ion rate were both zero; (2) meeting the limit by dividing the emission rate during startup or shutdown by the rate of polymer produced from the most recent performance test associated with a production rate greater than zero; or (3) keeping records that e stablish the operating parameters of the control device used to comply with the rule were maintained at the level established to meet the emission limit at maximum representative operating conditions

. This alternative compliance determination option

is not mandated.

Comment 4.2.11: Commenter 51 states that the past history of the SSM exemption and compliance problems for these source categories demonstrates a need for strong and more frequent monitoring, testing, and reporting requirements and enforcement provisions. The commenter declares that the EPA must implement enforcement provisions that prevent and remedy emission spikes, malfunctions, and other violations in a way that will be enforceable by citizens in the Title V permits for these source categori es. The commenter further states that the EPA should review the proposed monitoring requirements and ensure they are stringent enough to enable easy assessment of whether a facility is in full compliance with the standards within a short period of time of any violation.44

Response 4.2.11: We believe that the removal of the SSM exemption will reduce compliance problems that may have been associated with the exemption and excess emission spikes, as facilities have an incentive to avoid the related violations a nd penalties, without the need to institute more frequent monitoring, testing, and reporting requirements. We further believe that the monitoring requirements included in these rules are sufficient to ensure compliance with the standards regardless of whet her or when a violation occurs. Under the provisions of 40 CFR 63.15, the public can request access to reports submitted to the regulatory agency whenever they choose, with the exception of information protected through 40 CFR part 2 (e.g., confidential bu siness information). In addition, as discussed in section 5.0 below, we are promulgating requirements for electronic reporting of emissions test data that will improve public access to emissions information.

Comment 4.2.12: Commenter 51 states that additi onal requirements are needed for times of malfunctions, including requirements for automatic shut

- off of malfunctioning equipment, requirements to assign responsibility to the plant manager or high

- up staff member which allows only that person to restart t he equipment, and requirements that corrective actions be taken immediately. The commenter also states that for a facility that has had one or more malfunction, exceedance or other violation in the prior month, the facility must obtain written authorizatio n from the EPA to restart the equipment, and the EPA should only authorize the restart after making a public determination that the facility has instituted the corrective measures the EPA requires. The commenter further asserts that for a facility with 4 o r more exceedances or malfunctions in the same quarter, the EPA must require automatic shutdown of the operation for a period of time to conduct and publish a full investigation and ensure correction of the problem(s). Response 4.2.12: We disagree with th e commenter that the suggested additional requirements regarding malfunctions are necessary. The EPA believes that the monitoring requirements of the final rule are sufficient to ensure compliance with the emission standards, and that it is not necessary t o prescribe when or who may restart equipment that has malfunctioned. With respect to the commenter’s suggested reporting requirements, the reporting requirements in the final rules already require malfunction reporting and the affirmative defense provisio ns require that parties choosing to assert the affirmative defense meet additional malfunction reporting requirements. Any such reports submitted to the EPA are publicly available subject to the requirements of CAA section 114(c).



## 5.0 Electronic Reporting Requirements

Comment 5.1: Commenter 41 comments that the proposal to require the use of the Electronic Reporting Tool (ERT) is not appropriate as the costs and burdens imposed cannot yet be determined. Also, the regulated community cannot fully comment on the cost of duplicating reports using the ERT for Method 18 and other methods not currently supported by the ERT. Response 5.1: The rule only requires that test methods supported by the ERT be reported using the ERT. The EPA believes that the costs and b urdens of using the ERT are not significant for several reasons. The electronic reporting requirement does not add any additional testing and it does not change the timing of when test reports are due: the requirement only states that reports be submitted electronically. The ERT is fully functional and has been used successfully by industry for several years. It was designed to capture all of the information which is submitted45

in a typical test report and was also designed with input from States and the sta ck testing industry.

Comment 5.2: For test methods not supported by the ERT currently, such as Method 18, commenters 29 and 30 request that the EPA propose the addition of specific tests to the ERT and provide up to a 60 day comment period on the proposed addition and associated reporting forms and requirements. Commenters 38 and 41 note that without a formal notice that changes are being made to the ERT, facilities are at risk of noncompliance with the ERT requirements because they have no way to know whi ch test methods must be submitted to ERT unless they actively monitor the EPA’s web site. This commenter also states that the EPA should wait to propose the use of the ERT tool for these NESHAP until the tool is capable of managing the reports typically ge nerated by these industries. Commenter 41 recommends that the EPA remove the ERT requirement, or if the EPA insists on its inclusion, the ERT requirements should be limited to the methods which are incorporated in the ERT at the time of rule proposal.

Res ponse 5.2: The rule language is clear that only test methods supported by the ERT must be reported using the ERT. There is a list of ERT

- supported methods on the EPA’s ERT website. In addition, the methods are listed in the ERT itself. There should be no c onfusion as to

which methods are ERT

- supported. If the facilities wish, the EPA recommends joining the CHIEF listserv, which one can do by emailing join

- chief@lists.epa.gov , to be notified of

enhancements made to the ERT.

Comment 5.3: Commenters 29, 38, and 41 note that requiring electronic reporting to the EPA does not increase the ease and efficiency of data submittal for the regulated community because state agencies also want the reports submitted to them i n their own standard format. The commenters request that the EPA work with state and local agencies to provide a one

- stop location for submittal of air emissions testing results. Commenter 38 states the EPA should wait to propose the use of the ERT tool fo r these NESHAP until coordination with state and local governments is achieved to avoid duplicative reporting. Response 5.3: The EPA worked with State and local agencies as well as stack testing companies (who typically prepare test reports) to develop th e ERT. The ERT was designed to accept data and information that is typically collected during a performance test. Some State and local agencies have begun accepting the ERT as their reporting mechanism, and with experience, we believe acceptance by other S tates will increase. In some instances State and local agencies may still want a hard copy of a test report. The ERT can generate a printed test report or export the report to a word processor for reformatting. This report can be submitted to

the State or local agency. The EPA believes that electronic reporting is a more efficient way to collect test data and has set up a retrieval system such that State agencies can access files that have been submitted using the ERT. As more State agencies adopt electroni c reporting, we believe that the need for paper reports will be diminished.

Comment 5.4: Commenter 30 is concerned that confidential business information (CBI) would be made publicly available through electronic reporting of performance tests and suggests electronic submission of this information be voluntary only. Response 5.4: The commenter is incorrect that CBI would be made available through electronic reporting. Facilities can and should submit CBI according to the EPA’s CBI procedures (see 40 CFR 2.301), as they have always been able to do. As noted in the preamble to46

this f inal rule, owners or operators who claim that some of the information being submitted for performance tests is CBI must submit a complete ERT file including information claimed to be CBI on a compact disk, flash drive, or other commonly used electronic sto rage 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 ERT file with the CBI omitted must be submit ted to the EPA via Central Data Exchange (CDX).

Comment 5.5: Commenter 41 comments that under the proposed rule 40 CFR 63.1439(e)(10), all performance test reports must be submitted to the ERT within 60 days, but because the rule does not reference the ge neral provisions 40 CFR 63.10(d)(2), there is no allowance for obtaining additional time to complete this due to unforeseen circumstances or for the difficulties involved with completing particularly complex reports. Response 5.5: The EPA does not expect that facilities will need additional time to report emissions testing information because of the electronic reporting requirement. The electronic reporting requirement does not add additional testing: rather it only requires that reports be

submitted elect ronically using the ERT for ERT

- supported test methods. The EPA realizes there will be a learning curve for first

- time users of the ERT. The EPA has placed webinars and other training tools on the EPA’s ERT website to help ERT users. The ERT has been in us e for over 5 years now and the EPA has taken many steps to improve the tool and user

- friendliness, and as a result, the number of inquiries we receive has decreased significantly. The rules either reference the General Provisions for reporting performance tests or contain their own requirements. As allowed in 40 CFR 63.10(d)(2), the reporting requirements in this rule are modifying the basic requirements specified in 40 CFR 63.10(d)(2) by specifying that the performance test data be submitted electronically

.

Comment 5.6: Commenter 51 supports the EPA’s proposal to require electronic reporting. The commenter also states that the EPA should immediately disclose reports received through the ERT to the public on the internet within 7 days of receipt without req uiring a Freedom of Information Act (FOIA) request. Response 5.6: The EPA has established an electronic submittal and retrieval system such

that non

- CBI portions of test reports submitted via the CDX can be viewed by the public in the EPA’s Webfire databas e; a FOIA request is not necessary.



## 6.0 Pressure Relief Device Provisions

Readers are referred to section VI of the final rule preamble for this action for additional comments, and the EPA’s responses to those comments, on the proposed PRD provisions.

Co mment 6.1: Commenters 29, 33, and 41 request three years to add alarms to their PRD mechanical release indicator system, which would allow for time to properly research, specify, budget, purchase, install and test the equipment. Commenters 29 and 41 reques t that while the proposal preamble indicates a three

- year compliance period, this timeframe should be written into the proposed regulatory language. This commenter suggests specific compliance date information be inserted into 40 CFR 63.1311, 63.1364, and 63.1422.47

In contrast, commenter 51 states that the EPA must require more expeditious compliance with the PRD monitoring requirements to assure facilities meet the requirements “as expeditiously as practicable,” as required by the CAA. The commenter states that it is unclear why sources need 3 years and could not meet the requirements within 6 months or less. Response 6.1 : We do not agree with the commenter who asserted that these activities could be completed for all subject sources within 6 months or less . The first step that facility owners and operators have to accomplish is to read and understand the final rule requirements as they apply to them and their facilities. Then, although there may be some facilities that may be able to comply with the PRD mon itoring requirements within 6 months or less because they already have the necessary equipment in place to comply with the PRD monitoring requirements set out in the final rule, it is presumed that there will be numerous facilities that will need to

resear ch, purchase and test equipment to meet the PRD monitoring requirements. Once the necessary equipment is in place and tested, procedures will then need to be developed and personnel trained to ensure that procedures are properly implemented, for both safet y and compliance purposes. To accomplish any of these necessary steps within six months would be optimistic. Additionally, as provided for in CAA section 112(i)(3)(A), it was our intent to allow 3 years for facilities to comply with the new PRD compliance assurance requirements, and we have added provisions in 40 CFR 63.1311, 63.1364, and 63.1422 to explicitly state the dates for which compliance with these provisions will be required. We believe that this time is needed regardless of whether an owner or o perator of a facility chooses to comply with the PRD compliance assurance provisions by installing PRD mechanical release indicator systems and alarms or by employing parameter monitoring. This time period will allow facilities to research equipment and ve ndors, install, test, and properly operate the equipment by the compliance date.

Comment 6.2: Commenter 29 states that the EPA should clarify that the term “any release to the atmosphere” from PRDs in 40 CFR 63.1331, 63.1363, and 63.1434 is referring to a “pressure release” as defined in40 CFR 63.161 and 63.1361, rather than fugitive leaks that are covered under provisions for equipment leaks. Commenters 30, 38, 41, and 47 would also like the EPA to clarify that small “fugitive” releases will continue to b e regulated under existing equipment leak detection and repair requirements. Commenter 38 notes it is also technically infeasible to comply with a ban on fugitive emissions from all PRDs. Response 6.2: The provisions of 40 CFR 63.1331, 63.1363, and 63.143 4 have been amended to address specific technological concerns expressed by industry regarding the provisions proposed. However, as with the proposed provisions, the final provisions are intended to prohibit releases to the atmosphere from PRDs in organic HAP service, unless routed to a control device, process, or drain system. We have clarified in these sections that the releases discussed are “pressure releases” as defined in 40 CFR 63.1361 of subpart MMM, 40 CFR 63.161 as referred to in 40 CFR 63.1312 of subpart JJJ, and we have added the definition for “pressure release” to subpart PPP in 40 CFR 63.1423. We have also consolidated all of the fugitive leak monitoring requirements for PRDs under 40 CFR 63.1331 of subpart JJJ, 63.1363 of subpart MMM, and 63. 1434 of subpart PPP.

Comment 6.3: Commenter 29 states that the EPA should clarify that a pressure release from a PRD could be considered a malfunction rather than an automatic violation, and

commenter 30 states that pressure release devices are designed to prevent equipment from48

exceeding maximum allowable working pressures during upset situations and releases from them

should be considered malfunctions rather than violations

. Commenter 41 states that PRDs prevent catastrophic breaches of process equipmen t, which would result in far higher emissions than those resulting from a release from a PRD. The commenter asserts that the EPA is essentially asking plant operators to choose to allow the release to occur resulting in a violation, or prevent the release thus creating the potential for a catastrophic breach. The commenter states that any standard prohibiting releases to the atmosphere from PRDs must include appropriate routes to demonstrate the legal status of the vent without a presumption of non

- complian ce. Commenter 29 points out that the proposal preamble states the affirmative defense would be available for pressure releases related to a process or control device malfunction, however, the rule language of 40 CFR 63.1331(a)(9), 63, 1363(b)(4) and 63.14 34(c) states that such a release is a violation without further language regarding malfunctions. Response 6.3: In this CAA section 112(d) NESHAP rulemaking, we have developed

emission standards that are continuous and consistent with Sierra Club v. EPA . Th e final rules remove the SSM exemption and expressly prohibit pressure releases to the atmosphere from PRDs in organic HAP service, unless the PRD is routed to a control device, process, or drain system. We believe that PRD releases are caused by malfuncti ons, and in such occurrences the affirmative defense would be potentially available. While this is not explicitly stated in the text of 40 CFR 63.1331(a)(9), 63.1363(b)(4) or 63.1434(c), the affirmative defense is potentially available for all violations c aused by malfunctions, including PRD releases.

Comment 6.4: Commenter 29 states that the EPA should take into account existing programs that require reporting of PRD discharges and corrective action before establishing new PRD requirements. For instance, materials subject to CERCLA or SARA must have releases reported if over certain thresholds, some state agencies require reporting of upset emissions over a reportable quantity, and some states require excess emissions from PRDs to be reported as

deviations from the Title V permit conditions. Response 6.4: While reporting PRD releases may be required under certain circumstances for certain facilities or in certain areas of the country, it is not uniformly required for all of the facilities subject to the P& R IV, PEPO, or PAI MACT standards. To ensure this information is reported by all of these facilities, we are amending the rules to require that this information be reported in the semi

- annual periodic report.

Comment 6.5: Commenters 29, 30, 38, and 41 sug gest certain types of PRDs should be excluded from PRD monitoring requirements because they have a low potential to emit large quantities of HAP. Commenter 29 notes that such PRDs include those that discharge materials into another process vessel, are in p lace for thermal expansion on liquid lines, are associated with tubing or tubing sized lines and sampling systems, and those associated with portable equipment, which would also be more difficult to provide an alarm back to the control room due to their

mo vable nature. Commenter 41 adds to this list PRDs that are not in gas/vapor service, PRDs in systems with little potential for loss to the atmosphere (low vapor pressures), PRDs that are routed to a closed vent system and control device, and PRDs that are routed to a process. For PRDs with little potential for loss to the atmosphere, the commenter suggests that the EPA set a

de minimis reporting value equal to the reportable quantity (RQ) values in EPCRA and/or

CERCLA.49

Response 6.5: We do not agree with th e commenters that PRDs that emit smaller amounts of HAP should be excluded from PRD monitoring and reporting requirements. However, we have amended the final rules to exempt PRDs from monitoring requirements if a PRD in organic HAP service is designed and operated to route all pressure releases through a closed vent system to a control device or process. Both the closed vent system and control device (if applicable) must meet specified requirements.

Comment 6.6: Commenters 29 and 47 state that the EPA should clarify in 40 CFR 63.1331(a)(9)(iii), 63.1363(b)(4)(iii), and 63.1434(c)(3) that the trigger for reporting pressure releases are excess emissions and not malfunctions of pressure release indicators. Response 6.6: We agree with the commenters and hav e added language to these sections to clarify that owners or operators are only required to report releases when a pressure release to the atmosphere from a PRD in organic HAP service occurs during the reporting period.

Comment 6.7: Commenter 46 is concerned that the EPA may propose similar PRD requirements for other MACT standards that would affect its member companies, many of whom are small businesses that typically produce high

- value products in discrete batches. The commenter states that pre ssure relief events at these facilities are less likely and would not result in large quantities of HAP emissions. At such facilities, the PRD requirements fail from a cost

benefit perspective, and would present a significant financial burden if the same c ost estimates are used for other source categories as they were for the three source categories addressed in this proposal. Response 6.7: The EPA notes that this action has revised the provisions proposed for PRDs for the PAI, PEPO, and P&R IV source categ ories in response to comments received from the affected industry. Nonetheless, we cannot speculate as to whether or not the proposed requirements or final requirements in this action are appropriate for the source categories cited by the commenter whose m ember companies would not be subject to this rule. The EPA will consider those issues if and when they arise in future rulemakings for other source categories.

Comment 6.8: Commenter 41 states th at there is no indication that the EPA intended the

PRD moni toring devices to measure other parameters that are required in the deviation report, such as quantity of HAP emitted and duration of discharge, and therefore must clarify that the information required to be submitted in the report can be estimated using a vailable information. Response 6.8: We did not intend to indicate that the same equipment used to monitor PRDs would be required to measure HAP emitted and/or the duration of the discharge. Facilities may use available information, engineering judgement, a nd/or calculations to estimate emissions but must report how the emissions estimate was derived.

Comment 6.9: Commenter 41 states it has collected PRD data from 40 chemical sector sites, and disputes the EPA’s claims that PRD releases may not be identifie d and controlled in a timely manner, and asserts that several monitoring methods are commonly used by companies to identify PRD releases. The commenter further claims that PRD releases to the atmosphere are extremely infrequent, which is inconsistent with the EPA’s claim that such releases are common, citing data from the South Coast Air Quality Management District (SCAQMD) in support of Proposed Amended Rule 1173. The commenter states that PRD releases are typically of short

duration and it is in the best interest of a plant operator to detect PRD releases even without any50

requirement. The commenter states that emissions to the atmosphere from PRD releases are usually small, and the proposed requirements would not provide additional information related to

t he occurrence of higher emission releases and would not result in faster resolution of the

situation. In contrast, commenter 51 states that the EPA must finalize the prohibition on emissions from PRDs and states there is no valid justification for retainin g any exemption from the

standards. Response 6.9: We agree with commenter 51 that pressure release emissions from PRDs should not be permitted to occur. Regardless of whether commenter 41 is correct that releases are infrequent, of short duration, and emis sion releases are of small quantities, PRD releases of HAP emissions do occur, are considered to be the result of malfunctions, and are prohibited. If any pressure release events that occur are related to a process or control device malfunction, the

owner or operator could potentially claim the affirmative defense to civil penalties.



## 7.0 Source Category Specific Comments

7.1 Source Category Specific Comments

– Group IV Polymers and Resins

Readers are referred to section VI of the final rule preamble for th is action for additional comments, and the EPA’s responses to those comments, on the proposed regulation of previously

- unregulated sources in the P&R IV MACT standards.

Comment 7.1.1: Commenter 33 notes that the EPA did not include the styrene acrylonitri le resin (SAN) resins manufacturing facility it operates in Louisville, Kentucky in the risk assessment for the P&R IV source category. However, in detailed modeling that has been conducted for the facility, the SAN resins manufacturing cancer risks are le ss than 1

- in

- 1 million to the maximally exposed nearby resident and the non

- carcinogenic risks are less than 0.01. The

commenter believes this information confirms the low risks the EPA found for this source
category. Commenter 50 suggests that another fac ility, INEOS, which produces acrylonitrile butadiene styrene (ABS) in Addyston, Ohio, should potentially be included in the risk assessment for one or both of the ABS and SAN source categories. Response 7.1.1 : We have added these facilities to the risk ass essments for the SAN source category (Zeon) and the ABS source category (INEOS ABS). The INEOS ABS facility does not appear to produce SAN resins and was not added to the risk assessment for that source category. The results of the revised risk assessment for the source categories can be found in the final Residual Risk Assessment for 7 Source Categories , available in the docket for this action (EPA

HQ

- OAR

- 2011

- 0435). We note that the risk estimates for these facilities did not change the

maximum risk level s to the most exposed individual for the source categories and did not affect our determinations regarding risk acceptability and ample margin of safety. 9

Comment 7.1.2: For Subparts JJJ and PPP, commenter 29 suggests adding the definition

of PRD from the HON directly to these subparts to improve clarity. For Subpart PPP, the

9 See U.S. EPA’s Residual Risk Assessment for 7 Source Categories in the docket for this rulemaking.51

commenter also suggests that, for consistency, the term “relief valve” as used in Subpart PPP be changed to “pressure relief device.” Commenter 30 states that it is unclear what the E PA considers a “pressure relief device.” For example, it is unclear whether the safety devices on process vessels intended to release under high pressures or those intended to open and close due to working losses would be considered “pressure relief device s.” This commenter also suggests the EPA use the definition of pressure release device from the HON. Response 7.1.2: We agree with the commenters that using the definition of PRD from the HON and adding that definition to these rules would enhance clarity, and we have revised the definitions in each subpart accordingly. We have also revised subpart PPP to refer to “pressure relief device” rather than “relief valve”.

Comment 7.1.3: For Subpart JJJ, commenter 29 pointed out that the proposed rule had

incorre ct citations in 40 CFR 63.1335 for records and reporting of malfunctions. Response 7.1. 3: We agree with the commenter that there was a referencing error and have revised 40 CFR 63.1335 to correct these references.

Comment 7.1.4: Commenters 29 and 41 poin t out that a malfunction of emissions monitoring equipment could lead to an excursion because there would be an absence of monitoring data to demonstrate what the emissions were during that time. These commenters and commenter 48 suggest the EPA reinstate the proposed removal of provisions in subparts JJJ and PPP that allow one excused excursion per reporting period so one such loss of monitoring data

will not itself result in a violation of the emission standard. Response 7.1.4: The EPA recognizes that monitoring system malfunctions do not necessarily result in emissions greater than allowed by the standard. The provisions of 40 CFR 63.1326(e) of subpart JJJ and 63.1430(d) of subpart PPP allow that monitoring system breakdowns, repair

s, calibration checks, and zero (low

- level) and high level adjustments are not required to be included in the calculations to determine whether there has been sufficient monitoring data collected.

Comment 7.1.5: Commenter 50 supports the EPA’s conclusion that the residual risks associated with the ABS and SAN source categories are acceptable and that additional technological requirements are not necessary to reduce risks. The commenter notes that since the P&R IV NESHAP was implemented in 1996, the emissio ns of acrylonitrile have dropped by 82% according to the TRI, which supports the conclusion that the emissions from these source categories are being managed well by the current NESHAP. Response 7.1.5: We thank the commenter for this feedback.

Comment 7.1.6: One commenter (61) identified several incorrect or missing references in subpart JJJ that should be corrected or added, including: removing the reference to 40 CFR 63.7(e)(1) in 40 CFR 63.1333(a)(1); removing the proposed reference to “monitoring sy stem malfunction” in 40 CFR 63.1335(d)(7); removing the reference to 40 CFR 63.1335(b)(1)(i)(B) and 40 CFR 63.181(g)(2)(iii) in entry §63.8(c)(1)(ii) in Table 1; and revising the proposed references in 40 CFR 63.1335(b)(1)(i)(B) and (b)(1)(ii). Response 7. 1.6: The EPA has corrected the identified errors in the final rule.52



### 7.2 Source Category Specific Comments

– Pesticide Active Ingredient

Production

Comment 7.2.1: Commenter 29 suggests the language of 40 CFR 63.1365(c)(2)(i)(D)(3) and the definition of “pr ocess condenser” be revised to clarify that the initial process condenser demonstration requirements apply only where a HAP is heated above its boiling point, only apply to HAP associated with batch process vents, and do not apply to HAP as an impurity. Th e commenter also requests that an option be provided to measure the liquid temperature in the receiver as an alternative to measuring the exhaust gas temperature. The commenter notes that similar amendments were made in 2008 to the condenser provisions in the MON. Response 7.2.1: The EPA disagrees with the commenter that it is necessary to clarify when the initial demonstration requirement for process condensers applies, as we believe that the existing language is clear as to when it is necessary to conduct an initial demonstration. In addition, the proposed revisions to the MON cited the commenter have not been finalized, nor were they proposed in this action, and as such, we do not believe it to be appropriate to adopt them at this time. We also disagree t hat it is necessary to revise the definition of “process condenser” such that it only applies to condensers that recover material from batch process vents, as we believe that the existing definition is sufficient. The EPA disagrees that an option should be provided for measuring the liquid temperature in the receiver as an alternative to measuring the exhaust gas temperature. The EPA’s concern about the alternative parameter proposed to monitor is that we are unsure whether the receiver liquid temperature w ould be as sensitive an indicator of the condenser performance as the exhaust gas temperature. For example, if the receiver liquid has a relatively high flow rate, its temperature may not fluctuate nearly as much as the exhaust gas temperature. If this wer e the case, it would be more difficult to use the receiver liquid temperature to identify periods when the condenser is not achieving a high enough removal efficiency to ensure compliance with the applicable HAP emission standard.

Comment 7.2.2: Commenter 29 requests a change to the Precompliance Plan requirements so that sources that had not previously submitted a Precompliance Plan could submit one when they plan to change their compliance approach due to process changes or new information after the comp liance date. Response 7.2.2: We agree with the commenter and in response to the comment we have revised the Precompliance Plan/Report requirements in each of the three MACT standards accordingly. Since a Precompliance Plan/Report is only required where cer tain compliance options are chosen or alternative compliance options are being requested, not all existing sources would have submitted a Precompliance Plan/Report prior to the compliance date and not all new sources would have submitted one with the appli cation for construction or reconstruction. The revisions added in this action clarify that sources may submit a Precompliance Plan/Report to request alternative compliance options after the compliance date has passed or construction or preconstruction appl ications have already been submitted.

Comment 7.2.3: Commenter 29 requests an alternative monitoring option for packed scrubbers to allow measurement of the liquid

- to

- gas ratio in lieu of the scrubber liquid flow rate or pressure drop. The commenter state s this is another good indicator of performance and allows for better control in operations. The commenter notes that the HON and 40 CFR part 63, subpart SS contain requirements that allow for the recording and reporting the scrubber liquid to gas53

ratio an d the pH of the scrubber effluent to demonstrate compliance for scrubbers used with other control devices for halogenated streams. Response 7.2.3: We agree with the commenter and in response to the comment we have revised the requirements for packed scrubb ers accordingly. By allowing the measurement of the liquid

- to

- gas ratio in lieu of the liquid flow rate or pressure drop in the scrubber, facilities will be able to drop their liquid flow rate during periods of low vent flow, but still maintain adequate

li quid flow to scrub the gas stream. As the commenter correctly points out, this will also make the requirements consistent with the HON and 40 CFR part 63, subpart SS.

Comment 7.2.4: Commenters 41 and 45 request that the EPA revise the definition of
“Pesti cide Active Ingredient” to reflect changes in references used in the definition since promulgation of the rule. The current definition refers to the EPA form 3540

- 16, the Pesticides Report for Pesticide

- Producing establishments, which has changed since the 1999 version. The commenters suggest the rule be amended to reference the 1999 version of the EPA form 3540

- 16, which would eliminate the need to modify the rule when the form is modified in the future. Response 7.2.4: We agree with the commenter and in r esponse to the comment we have revised the definition of “Pesticide Active Ingredient” to reference the 1999 version of EPA form

3540

- 16. The revised definition clarifies that PAI materials are identified by product classification codes used to represent P AIs, and are the same codes used in block 19 of the 1999 version of EPA Form 3540

- 16, the Pesticides Report for Pesticide

- Producing Establishment.

Comment 7.2.5: Commenter 41 comments that when considering the total amount of operating hours and the 75% m onitoring data requirement for a day, the owner/operator should be allowed to subtract the time during periods of monitoring system breakdowns, repairs, calibration checks, and zero (low

- level) and high

- level adjustments. These provisions should be

added t o 40 CFR 63.1366(b)(7) regarding excursions to make Subpart MMM consistent with Subpart JJJ. Response 7.2.5: We disagree that facilities should be allowed to subtract the time periods referenced by the commenter for the 75% monitoring data requirement. The 25% missing data allowance is intended to already include such time periods

Comment 7.2.6: One commenter (61) identified several incorrect or missing references in subpart MMM that should be corrected or added, including: removing references to 40 CFR

63 .1366(b)(8)(iv) in 40 CFR 63.1366(b)(8), (b)(8)(i), (b)(8)(ii), and (b)(8)(iii); and revising 40 CFR 63.1367(e) to reference subpart F instead of subpart G. Response 7.2.6: The EPA has corrected the identified errors in the final rule.



### 7.3 Source Category Specific Comments

– Polyether Polyols Production

Comment 7.3.1: Commenter 51 states that the EPA must set limits for vents at facilities where the total vent output of nonepoxide organic HAP is less than 11,800 kg/yr for the PEPO source category. The comm enter states that the EPA lacks the authority to exempt any sources

that emit HAP. Response 7.3.1: We disagree that additional limits are required for nonepoxide organic HAP vents that emit less than 11,800 kg/yr. The 11,800 kg/yr applicability criteria le vel was included in the existing PEPO standard based on 40 CFR part 63, subpart U (Group I Polymers54

and Resins), which adopted the Batch Achievable Control Technology (ACT) control applicability criteria 10 that apply to VOC emissions from batch process vent s and represents a 90 percent VOC control level. The methodology used to develop control options and levels in the Batch ACT utilizes the parameters of annual emissions and average flow rate to identify which streams are reasonable to control from a cost a nd technical feasibility standpoint. As with the HON and other MACT standards, the control applicability criteria set out in the Batch ACT were based on general vent stream characteristics, and not on process

- specific parameters. 11 Due to
the similarities b etween the processes studied in the ACT (i.e., Synthetic Resins Manufacturing, Synthetic Organic Chemicals Manufacturing Industry), and the general nature of the applicability criteria, the EPA concluded that these criteria were appropriate to use in defin ing the MACT floor for nonepoxide organic HAP batch process vents. The 90 percent Batch ACT control level applicability criteria was selected because the estimated cost

- effectiveness for this level was comparable to the cost

- effectiveness for the HON conti nuous vent provisions (approximately $3,000 per Megagram) and was determined to represent the MACT floor for batch process vents. Under the final PEPO MACT standards, if the emissions are greater than 11,800 kilograms per year (26,000 pounds per year), the y are used to calculate a threshold flow rate. This threshold flow rate is then compared to the actual combined annual average flow rate for all the vents. If the actual combined annual average flow rate is less than the threshold flow rate, the group of v ents is Group 1 and subject to Group 1 control requirements. If the annual emissions of TOC or nonepoxide organic HAP from the combination of process vents from batch unit operations that are associated with the use of nonepoxide organic HAP to make or mod ify a polyether polyol for a PMPU are less than 11,800 kg/yr, the owner or operator of that PMPU is not required to comply with the control requirement provisions but are subject to recordkeeping and reporting requirements. (64 FR 29420, June 1, 1999). Thu s, in the PEPO MACT standards we did not “exempt” sources that emit HAP from standards, but instead structured the way our standards applied to the HAP sources depending upon the results of the floor analysis showing what kinds of control requirements shou ld apply to which sources.

Comment 7.3.2: One commenter (61) identified several incorrect or missing references in subpart PPP that should be corrected or added, including: removing the reference to 40 CFR 63.6(i)(6)(i)(D) in 40 CFR 63.1422(d)(2) and (e) (1) and 63.1439(e)(4)(ii); revising the reference to paragraph (j)(2)(iv) to be paragraph (j)(2)(v) in 40 CFR 63.1427(k)(3)(ii); revising the reference to 40 CFR 63.1430(j) or (k) to be 40 CFR 63.1430(i) or (j) in 40 CFR 63.1428(h)(2)(ii); revising the ref erence to Table 5 to be Table 7 in 40 CFR 63.1429(d)(1); revising the reference to 40 CFR 63.1430(d) to be 63.1438(a)

- (d) in 40 CFR 63.1429(d)(1); removing the reference to 40 CFR 63.1439(e)(3)(ii)(A) in 40 CFR 63.1434(d); removing the reference to paragra ph (g) in 40 CFR 63.1438(f)(4); removing the reference to 40 CFR 63.9(b)(6) in 40 CFR 63.1439(e)(3); adding a reference to 40 CFR 63.113(i) in 40 CFR 63.1439(e)(5)(vii) and (e)(6)(iii)(D)(3); revising the entries for §63.1(a)(7) and (8) and

10 U.S. Environmental Protection Agency. “Control of Volatile Organic Compound Emissions From Batch

Proc esses.” February 1994. (EPA

- 453/R

- 93

- 017)

11 U.S. Environmental Protection Agency. Hazardous Air Pollutant Emissions from Process Units in the Elastomer Manufacturing Industry

– Supplementary Information Document for Proposed Standards. Memorandum from Phil Norwood, EC/R to Leslie Evans, EPA. “MACT Floors and Regulatory Alternatives for the Elastomer Production Industry (Polymers and Resins I).” pgs. 7 and 10.55

§63.1(c)(4) in Table 1 to be reserved; adding entries for §63.107 and §63.153 in Table 2; and revising the entry for §63.160

- 63.182 in Table 2 to reference 40 CFR 63.1434(b) through (h) instead of 40 CFR 63.1434(b) through (g). Response 7.3.2: The EPA has corrected the i dentified errors in the final rule.

Comment 7.3.3: One commenter (61) identified several incorrect or missing references in subpart PPP that they believed should be corrected or added, including: adding several references to definitions in subparts A, F, G, and H in 40 CFR 63.1423; and adding entries for Tables 1, 2, and 3 of subpart F in Table 2. Response 7.3.3: The EPA disagrees that the revisions suggested by the commenter are

necessary.



## 8.0 Other Comments

Comment 8.1: Commenter 26 suggests that busine sses choose to use good plastic resin, such as the polyolefin and waste rice plastics her business uses, which do not generate poisonous pollution. The commenter states that government support for biomass energy companies will help our environment. The com menter and commenter 28 also support the establishment of standards for previously unregulated P&R IV emission points. Response 8.1: We acknowledge the commenter’s support for the additional standards for unregulated P&R IV emission points. The commenter’s other remarks are beyond the scope of

this rule.

Comment 8.2: Commenter 34 asks that the EPA raise the national emission standards to be stricter and provide for cleaner air. Response 8.2: We believe we have taken the appropriate actions to address the mandates of CAA section 112(d)(6) and (f)(2) for these source categories.

Comment 8.3: Commenter 38 agrees with and incorporates the comments by ACC and CRWI by reference. Commenters 45 and 48 note that they fully support the comments provided by ACC. Co mmenter 49 also supports ACC’s comments, including those of ACC’s Formaldehyde Panel. Commenter 41 states that it adopts and incorporates the comments of the SSM Coalition by reference. Response 8.3: We have addressed all of the comments from ACC, CRWI, an d the SSM

Coalition.

Comment 8.4: Commenter 46 is concerned about cumulative cost impacts of all the recent rules the EPA has been promulgating, particularly for small businesses. The commenter notes that the compliance costs are daunting when considering the PRD requirements, the reconsidered Chemical Manufacturing Area Source (CMAS) rule, the Boiler MACT and area source rules, the proposed heat exchangers standards, and the proposed uniform standards. Response 8.4: We do not believe there will be a large cumulative cost impact for the facilities regulated by 40 CFR 63 subparts JJJ, MMM, or PPP. The revisions to the CMAS rule, the boiler MACT, the proposed heat exchanger standards and the proposed Uniform Standards do not apply to or impact the affected fa cilities subject to subparts JJJ, MMM, or PPP. In regards to the PRDs, we do not believe the revised requirements included in the final rules for56

PRD monitoring impose significant compliance costs. As explained in the preamble to the final rule, many facil ities will only be required to perform additional recordkeeping and reporting

with their semi

- annual reports, while others will be adding work practices that incur minimal capital or annual costs. Additionally, in our economic impacts analysis for the prop osed rule, we found that only two of the 42 parent companies with facilities in these three source categories would be classified as small businesses, and we found that the cost imposed on these companies is a small fraction of the companies’ revenues and should yield small economic impacts on these chemical producers. We have certified officially that there were no significant impacts to a substantial number of small businesses (or SISNOSE) for this rule.

Comment 8.5: Commenter 51 states that the EPA is required to set standards that satisfy section 112(d) to control each pollutant at the maximum achievable level rather than re

- applying the existing standards that are not pollutant specific. The commenter further states that if the

EPA intends to use tota l organic HAP as a surrogate for each emitted pollutant, it must satisfy the 112(d) test to use a surrogate to do so. For the PEPO source category, it appears epoxide may also be a surrogate, which the EPA must rationally justify using or set pollutant

- spe cific limits. Response 8.5: Consistent with CAA section 112(d)(2) and (3),the EPA has set standards for all HAP emitted from the PEPO source category. Contrary to the commenters’ assertion, the EPA is not obligated to set a separate MACT standard naming ea ch and every individual HAP emitted by PEPO sources. Rather, as the Court recognized in Mossville Envt’l Action Now v.

Whitman , 370 F.3d 1232, 1242 (D.C. Cir. 2004) (quoting Nat’l Lime Ass’n v. EPA , 233 F.3d at 637), the EPA has authority to use surrogates to regulate HAP “if it is reasonable to do so[.]” Nor are we required, in implementing sections 112(f)(2) and (d)(6), to revisit prior MACT determinations, including surrogacy determinations in those MACT determinations. We note, however, that epoxide is not used as a surrogate in the PEPO source category. The rule contains emission limits specific to epoxide HAP and non

- epoxide HAP based on the HAP emitted and specific to each emission point.

Comment 8.6: Commenter 51 notes that it seems like an unusual coincidence for source categories to have “allowable” emissions approximately equal to “actual” emissions, as the EPA found, and this indicates the need for better monitoring and reporting to determine what the true

levels of emissions are. Response 8.6: Where facilities are following the requirements of the standards, the actual emissions will be equal to the emissions allowable under the standards if they are not pursuing emission reductions that go beyon d the level of the standards. This is common where work practices and equipment standards are required by the MACT standards. See the memorandum available in the docket, MACT Allowable Emissions and Risks for the Pesticide Active Ingredient, Polyether Poly ols, and Polymers and Resins IV Production Source Categories (Docket Item No. EPA

- HQ

- OAR

- 2011

- 0435

- 0007), for more information on the actual to

MACT

- allowable emissions analysis performed for these source categories.

Comment 8.7: Commenters 29 and 48 sta te that the EPA should clarify that the reporting requirements for excursions only apply to excursions that result in HAP emissions in excess of an applicable emission limit. The commenter also states that the EPA should only require quarterly reporting in subparts JJJ and PPP when an affected source has excursions during consecutive reporting periods. Quarterly reporting would place an unnecessary burden on an57

affected source when a single emission point has a single excursion and is redundant of the Title V requirements to immediately report excess emissions that pose a significant hazard to the surrounding community and to report deviations semi

- annually. The commenter suggests the following language: §63.1335(e)(6)(xii)(A)(1): The owner or operator of a n affected source shall submit quarterly reports for a period of 1 year for an emission point or process section if the emission point or process section meets the conditions of (e)(6)(xii)(A)(1) and (D) of this section for two consecutive reporting period s. Response 8.7: We disagree with the commenter that only excursions resulting in HAP emissions above the applicable emission limits should be reported. Excursions can result from monitoring parameter levels being outside established ranges or from a lack of sufficient data to determine compliance with the emission limits. These excursions are considered violations of the standards and must be reported in the semi

- annual report. However, we do agree that with the removal of the allowance for one excursion p er semi

- annual reporting period, this would result in facilities being required to perform quarterly reporting for the affected source if any point at that affected source experienced an excursion. This would be overly burdensome for both the facility and the reviewing agency and was not the intention of the original MACT standards. Accordingly, we have revised the language of subparts JJJ and PPP to require quarterly reporting only when there have been repeat excursions for the same equipment in consecutiv e semi

- annual reporting periods. This requirement will ensure that enhanced reporting is carried out for only for equipment with potential compliance issues.

Comment 8.8: Commenter 51 states that the EPA should create a community complaint

mechanism that ensures citizen complaints concerning air pollution receive an immediate response, in which the EPA commits to initiate an investigation and provide a publicly available report of the investigation results, including whether it leads to an enforcement acti on, within 7 days. Response 8.8: The EPA takes citizen pollution complaints seriously and is committed to responding to complaints. We invite you to help us protect our nation's environment by identifying and reporting environmental violations. The EPA's R eport an Environmental Violation website provides a way for you to report suspected environmental violations. ( http://www.epa.gov/compliance/complaints/moreinfor.html ) Assuring complian ce with our nation's environmental laws is one of EPA's primary commitments. In carrying out this responsibility, we use many different approaches. One approach is to seek help from you by asking you to provide EPA with information about potentially harmfu l environmental activities in your communities and workplaces. Reports from the public have led to state and federal enforcement cases and ultimately served environmental protection well.