December 6, 2012

National Emission Standards for Hazardous Air 

Pollutant Emissions for Chemical Manufacturing 

Area Sources - Reconsideration

Summary of Public Comments and Responses

on Proposed Rule (77 FR 5422, January 30, 2012)

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

Sector Policies and Programs Division

Research Triangle Park, NC 27711
December 6, 2012

i

(This page is intentionally left blank)
December 6, 2012

ii

Foreword

This document provides responses to public comments on the U.S. Environmental 

Protection Agency’s (EPA’s) proposed revisions to the “National Emission Standards for 

Hazardous Air Pollutants for Chemical Manufacturing Area Sources.” 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 EPA-HQOAR-2008-0334 by docket number.

This document provides a summary of the significant 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 parenthesis 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.
December 6, 2012

iii

Table of Contents

1.0 Background.......................................................................................................................... 1

2.0 Title V Permitting Requirements......................................................................................... 4

3.0 Requirements When Other Rules Overlap With the Final Rule .......................................... 7

4.0 Requirement to Conduct Direct and Proximal Leak Inspections......................................... 8

5.0 Requirement for Covers or Lids on Process Vessels........................................................... 8

6.0 Requirement to Conduct Leak Inspections When Equipment Is in HAP Service ............... 9

7.0 Applicability of the Family of Materials Concept ............................................................. 10

8.0 Startup, Shutdown, and Malfunction ................................................................................. 11

9.0 Affirmative Defense........................................................................................................... 12

10.0 Metal HAP Process Vents.................................................................................................. 18

11.0 Applicability ...................................................................................................................... 19

12.0 Compliance Date................................................................................................................ 21

13.0 Definitions.......................................................................................................................... 21

14.0 Other/Technical Corrections.............................................................................................. 22
December 6, 2012

iv

(This page is intentionally left blank)
December 6, 2012

1

1.0 Background

On January 30, 2012 (77 FR 4522), the U.S. Environmental Protection Agency (EPA or 

agency) proposed to revise the National Emission Standards for Hazardous Air Pollutants 

(NESHAP) for Chemical Manufacturing Area Sources (CMAS) in part in response to a petition 

for reconsideration from the American Chemistry Council (ACC) and the Society of Chemical 

Manufacturers & Affiliates (SOCMA) (collectively, “the petitioners”). The EPA has summarized 

and responded to several comments in the preamble to the EPA’s final action. This document 

presents summaries of the additional comments that were submitted and the EPA’s responses to 

those comments. The comments to which the EPA is responding to were submitted in 19 letters 

from industry representatives, governmental entities, and private citizens during the public 

comment period. In addition, the EPA received six comments and sets of materials from industry 

representatives following the close of the comment period. Although the EPA is not required to 

respond to these comments, to the extent practicable the EPA has responded to the 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.

TABLE 1. LIST OF COMMENTERS ON PROPOSED NATIONAL EMISSIONS 

STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR CHEMICAL 

MANUFACTURING AREA SOURCES

Docket Number a,b Commenter and Affiliation

116 Karen Thorne, Louisville Metro Air Pollution Control District

117 Alex Berger, Hospira Boulder

118 Sheila Holman, North Carolina Department of Environment and Natural 

Resources

119 Catharine Fitzsimmons, Iowa Department of Natural Resources

120 Paul Aud, Louisville Metro Air Pollution Control District

121 Shelley Schneider, Nebraska Department of Environmental Quality

122 Desi Chari, The Dow Chemical Company

123 Timothy Lafond, Battery Council International

124 David Darling and Tim Serie, American Coatings Association

125 Jeffrey Lang, Rhodia

126 Melvin Keener, Coalition for Responsible Waste Incineration
December 6, 2012

2

Docket Number a,b Commenter and Affiliation

127, 134 Carroll Wade McGuffey III, Tronox

128 Lorraine Gershman, American Chemistry Council

129 Barry Christensen, Occidental Chemical Corporation

130 Monte Shaw, Iowa Renewable Fuels Association

131 Russell Frye, SSM Coalition

132 Ron Walton, Clariant Corporation

133 Daniel Moss, Society of Chemical Manufacturers & Affiliates

135 Jade Fisher, Private Citizen

136

(Late Comment)

Lorraine Gershman, American Chemistry Council

137

(Late Comment)

Desi Chari, The Dow Chemical Company

138

(Late Comment)

Leslie Hulse, American Chemistry Council

139

(Late Comment)

Lorraine Gershman, American Chemistry Council

140

(Late Comment)

Lorraine Gershman, American Chemistry Council

141

(Late Comment)

Lorraine Gershman, American Chemistry Council

a Document ID identifies comments found in Docket No. EPA-HQ-OAR-2008-0334 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-2011-0334-XXXX, 

where “XXXX” represents the unique 4-digit document docket number). The unique document docket numbers 

presented in this table and document represent that unique docket number without the preceding “0”. For example, 

docket number EPA-HQ-OAR-2008-0334-0116 is presented as 116 in this table and within the text of this document.
December 6, 2012

3

A total of 19 written comments were received during the public comment period on the 

proposed revisions to the CMAS rule as part of the EPA’s reconsideration. The following 

sections provide a summary of these comments, as well as the EPA’s responses to these 

comments. We also provide summaries of the 6 late comments and materials submitted after the 

close of the comment period, and any responses thereto. For the purpose of orderly presentation, 

the comments have been categorized under the following topics:

Section 2: Title V Permitting Requirements

Section 3: Requirements When Other Rules Overlap With the Final Rule

Section 4: Requirement to Conduct Direct and Proximal Leak Inspections

Section 5: Requirement for Covers or Lids on Process Vessels

Section 6: Requirement to Conduct Leak Inspections When Equipment Is in HAP Service

Section 7: Applicability of the Family of Materials Concept

Section 8: Startup, Shutdown, and Malfunction

Section 9: Affirmative Defense

Section 10: Metal HAP Process Vents

Section 11: Applicability

Section 12: Compliance Date

Section 13: Definitions

Section 14: Other/Technical Corrections
December 6, 2012

4

2.0 Title V Permitting Requirements

Comment 2.1: One commenter (132) stated that the distinction between synthetic area 

sources that have taken operational limits to maintain area source status and those that have 

installed controls for the purposes of requiring a title V permit is baseless, and that there is no 

substantive difference in the impact of the emissions on the environment.

Response 2.1: The EPA continues to believe that it is appropriate to make the distinction 

between synthetic area sources that installed controls and those that took operational limits. In 

the preamble to the 2009 final rule, the EPA noted that the CMAS categories are different from 

other area source categories we have exempted from title V because the CMAS categories 

include a large number of synthetic area sources that installed controls to significantly reduce 

their hazardous air pollutant (HAP) emissions and the sources in the other categories generally 

have considerably lower emissions of HAP before control. We then stated that at least 10 percent 

of the estimated 75 facilities that are synthetic area sources for HAP by virtue of installing 

controls have uncontrolled HAP emissions over 100 tons per year (tpy). We also indicated that 

our information showed that many of the sources are located in cities, and often in close 

proximity to residential and commercial centers where large numbers of people live and work. 

We further stated that these synthetic area sources have significantly higher emissions potential 

when uncontrolled than the other sources in the CMAS categories, and that they are much more 

like the major sources of HAP subject to the Hazardous Organic Chemical Manufacturing 

NESHAP (HON) and the Miscellaneous Organic Chemical Manufacturing NESHAP (MON). 

Commenters have not provided data or other information to rebut our assessment of the CMAS 

categories or shown that the sources that took operational limits have potential emissions that 

approach the potential emissions of the synthetic area sources that installed controls.

Comment 2.2: One commenter (138) noted that there are a similar number of synthetic 

area sources in the boiler area source category and that they are not being subjected to title V. 

The commenter does not believe that the number of sources affected by the title V requirement 

suggests that reliance on the Federally Enforceable State Operating Permit (FESOP) program is 

inadequate, but rather is a sign of the effectiveness and efficiency of the program. 

Response 2.2: The EPA disagrees with the commenter that the decision not to require 

title V for the boiler area source category has any implications on the decision to require title V 

in this rule. The decision to require title V for certain CMAS facilities was based on the specific 

facts associated with the CMAS categories as set forth in the rulemaking record, including the 

preamble to the 2009 final rule (74 FR 56013-56014). The commenter has not demonstrated that 

the facts associated with the boiler area sources are similar to the CMAS area sources, including 

whether the synthetic area sources in boilers that installed controls have similar potential 

emissions to the potential emissions we identified for CMAS synthetic area sources that installed 

controls.

Further, the commenter appears to assume that all FESOP programs are equivalent and 

that the EPA has concluded that FESOP programs are inadequate. We do not agree with the 

commenter and note that the decision to require title V was not based on a conclusion that 

FESOP programs are generally “inadequate,” as stated by the commenter. Instead, for the 

reasons stated in the record, the EPA determined that title V permitting was appropriate for a 

certain subset of CMAS facilities. 
December 6, 2012

5

Comment 2.3: One commenter (138) questions what was meant by the EPA’s 

assumption that “at least” 10 percent of the estimated 75 synthetic area CMAS facilities “have 

uncontrolled HAP emissions over 100 tpy.”

Response 2.3: The EPA’s estimate that at least 10 percent of the synthetic area source 

facilities have uncontrolled emissions greater than 100 tpy means that, but for the installation of 

air pollution control devices, emissions from these facilities would be in excess of 100 tpy.

Comment 2.4: One commenter (122) stated that the title V permit requirement should 

only apply to facilities that installed a federally-enforceable control device after the proposal date 

of an otherwise applicable maximum achievable control technology (MACT) standard in order to 

become a synthetic area source.

Response 2.4: The EPA disagrees that the title V requirement should only apply to 

sources that installed a control device after an applicable MACT standard was proposed, as we 

do not believe that the installation date of the control device is relevant for this requirement. 

Regardless of when the controls were installed, these facilities would be major sources of HAP 

emissions but for the use of the control device(s). We believe these sources are generally larger 

than area sources that took operational limits and natural area sources and that title V is 

appropriate for such sources.

Comment 2.5: One commenter (122) stated that if the EPA finalizes the title V permit 

requirement, it should clarify that a facility that installed a federally-enforceable control device 

for non-Table 1 HAP and the facility is only subject to the CMAS rule due to the presence of 

Table 1 metal HAP, or vice-versa, is not subject to the title V permit requirement. The 

commenter believed that this is consistent with previous responses to comments by the EPA.

Response 2.5: The EPA believes that the revised title V requirement accomplishes what 

the commenter suggests and provides a straightforward approach for determining applicability 

of title V. As finalized, the title V requirement applies only to facilities that installed a federallyenforceable control device on an affected chemical manufacturing process unit (CMPU). Thus, if 

a facility installed a federally-enforceable control device on the CMPU containing only nonTable 1 HAP (and is therefore not subject to the CMAS rule), and did not install a federallyenforceable control device on the CMPU that contains Table 1 metal HAP (and is therefore 

subject to the CMAS rule), the facility would not be subject to the title V requirement.

Comment 2.6: One commenter (124) stated that the EPA should clarify how the title V 

requirement applies, particularly an “affected CMPU” and the “first substantive compliance 

date” of a rule.

Response 2.6: The EPA is unsure exactly what the commenter is asking. However, we 

note that an affected CMPU in the final CMAS rule is one that contains Table 1 HAP above the 

0.1 percent/1.0 threshold at an area source. A source that did not obtain a federally enforceable 

limit on HAP emissions in advance of the first substantive compliance date of an otherwise 

applicable major source NESHAP would be subject to the major source NESHAP, not the CMAS 

rule. The first substantive compliance date is generally considered the date on which a source 

must comply with substantive NESHAP requirements (e.g., emissions standards), and it does not 

include requirements such as initial notifications. If the commenter is unsure of applicability of a 

major source NESHAP, or whether the compliance date for a specific requirement constitutes 
December 6, 2012

6

the first substantive compliance date, it should contact the delegated state authority or the 

appropriate EPA regional office.

Comment 2.7: One commenter (129) stated that there are numerous situations in which 

they were unsure as to whether or not the title V requirement would apply. Specifically:

1. The 2009 final rule limited the Title V requirement to sources that “installed a control 

device on a CMPU after November 15, 1990.” However, the reconsideration proposal 

referred to sources that “installed a federally-enforceable control device on an 

affected CMPU by the first substantive compliance date of an otherwise applicable 

MACT standard.” How far back in time must be considered?

2. A synthetic area source originally installed a control device in 1951 to limit personnel 

exposure to a pollutant and for equipment protection purposes. The control device 

was not installed to reduce HAP emissions below major source levels. Does the 

purpose for installing the control device matter?

3. The reconsideration proposal used the phrase “installed a federally-enforceable 

control device.” Does the control device have to currently be federally-enforceable or 

federally-enforceable at the time it was installed?

4. A facility relies on both production limits and control devices to maintain synthetic 

area source status. Can the facility restructure their synthetic area source permit to 

rely solely on production limits or control devices on non-affected CMPUs?

5. A facility currently has a control device for emissions from non-affected CMPUs. 

Would the installation of a duct from a vent in a newly regulated CMPU to the 

existing control device trigger the title V permit requirement?

6. A natural area source subject to the CMAS rule is required to install a control device 

on an affected CMPU as a result of compliance with the CMAS rule. Would the 

installation of this control device trigger the title V permit requirement?

7. A natural area source subject to the CMAS rule installs a control device in the future 

because of a production increase that would trigger a MACT standard. Would the 

installation of this control device trigger the title V permit requirement?

8. A natural area source is not currently subject to the CMAS rule and will only be 

subject to the CMAS rule because a Table 1 HAP will be used as part of a production 

increase in the future. The facility installs a control device because the production 

increase would trigger a MACT standard. Would trigger the title V permit 

requirement?

Response 2.7: As stated previously in this document and in the preamble to the final rule, 

the EPA has clarified the applicability of the title V permit requirement and believes that this 

revised language will answer many of the commenter’s questions. Specific answers to the 

commenter’s questions are below. The EPA notes, however, that these responses are based on 

the limited information provided by the commenter, and that sources should not consider these 

responses to be official applicability determinations or otherwise constitute final decisions by the 

EPA on the applicability of the title V requirement. 

1. The installation date of the control devices is not a determining factor as to whether a 

title V permit is required. The installation of any federally enforceable control device 

on an affected CMPU in order to maintain synthetic area source status, regardless of 

age, would trigger the title V requirement.

2. The purpose of the control device does not matter for the title V requirement.
December 6, 2012

7

3. The control device must currently be federally-enforceable and be necessary to 

maintain synthetic area source status. If a control device is necessary to maintain 

area source status, and the requirement to use the control device is not federallyenforceable, the source may be a major source subject to a major source NESHAP 

(e.g., the HON or the MON).

4. If a facility restructures its permit in order to rely solely on production limits or 

control devices on non-affected CMPUs, the facility would no longer be subject to the 

title V requirement after that point.

5. If the installation of the new duct from the affected CMPU is to an existing control 

device that is federally-enforceable, and the control of the affected CMPU is 

necessary in order to maintain synthetic area source status, then it would trigger title 

V applicability. If controls are in place only on non-affected CMPU, title V would not 

apply.

6. A natural area source is not subject to the title V permit requirement, so long as it 

continues to be a natural area source.

7. If the production increase would cause a natural area source to become a major 

source absent installation of a federally-enforceable control device on the affected 

CMPU, then the installation of the control devise would trigger title V applicability. 

If controls are installed only on non-affected CMPU, title V would not apply.

8. If a natural area source not subject to the CMAS rule begins using a Table 1 HAP in 

conjunction with a production increase, the CMPU would be an affected CMPU 

subject to the CMAS rule. The source could maintain area source status through the 

installation of federally-enforceable controls, and, if the controls must be installed on 

the affected CMPU to maintain area source status, then the source would be subject 

to title V. However, the source could avoid title V permitting if it instead controlled 

emissions from a CMPU that is not subject to the CMAS rule.

Comment 2.8: One commenter (129) stated that if the EPA should choose to finalize the 

title V permit requirement, it must clarify whether the title V permit application must be 

submitted upon start-up or within 12 months after plant startup.

Response 2.8: The EPA intended in the proposed rule to propose to provide both new 

and existing sources with 12 months to submit their title V permit application after the CMAS 

rule amendments were finalized; however, the EPA agrees that the proposed rule revisions were 

ambiguous in regard to new CMAS sources (i.e., CMAS sources that began construction or 

reconstruction after the October 6, 2008, proposed rule was published in the Federal Register). 

The EPA has clarified in the final rule that all sources subject to the title V requirement, both 

new and existing, will be provided 12 months to submit their title V permit application.

3.0 Requirements When Other Rules Overlap With the Final Rule

Comment 3.1: One commenter (133) recommended that the EPA eliminate the 

overlapping standards provision, as it may be difficult to determine which provisions are more 

stringent, which may lead to a disagreement between the source and the EPA or delegated 

authority.

Response 3.1: It is not clear to the EPA how eliminating the overlapping provisions 

language would resolve the issue, as a source would then be required to comply with each 
December 6, 2012

8

overlapping rule independently. This provision is provided as an alternative to relieve 

compliance burden, and the EPA believes that it provides flexibility for a source in choosing how 

to comply with the standard. The alternative was intended as a means of reducing the 

compliance burden without diminishing the level of environmental protection provided by each 

rule. There is no obligation for the source to adopt this alternative approach, and as such, the 

EPA does not agree that there is any unreasonable burden associated with it. If sources subject 

to multiple NESHAP prefer to comply with each standard independently, the sources are not 

required to avail themselves of the overlapping requirement provisions.

4.0 Requirement to Conduct Direct and Proximal Leak 

Inspections

Comment 4.1: One commenter (129) requested that other instrument based leak 

monitoring programs that have been demonstrated to be equivalent or better than the sensory 

detection methods should be allowed as well, as consistent with 40 CFR part 63, subpart R. The 

commenter was concerned that some equipment may not be adequately inspected without the use 

of an aerial lift, scaffold, or ladder, and notes that this type of monitoring is only required on an 

annual basis for the HON leak detection program. The commenter also suggested that the EPA 

add a provision that sensory inspections be conducted at distances as close as practical to 

equipment, but at distances that meet an individual site safety plan.

Response 4.1: The EPA disagrees with the commenter that providing this alternative 

language is necessary, as an alternative means of compliance using Method 21 for leak detection 

inspections is already provided in the final rule. As noted in the reconsideration proposal, the 

EPA did not exempt difficult or unsafe to monitor equipment because “[s]ensory monitoring 

does not require intimate contact with each piece of equipment to be effective at identifying 

leaks.” See §63.11495(a)(3) of the revised final rule. Similarly, the EPA does not believe that it 

is necessary to add provisions in the final rule to explicitly state that inspections be conducted as 

close as practical.

Comment 4.2: One commenter (128) requested that the EPA permit the use of pressure 

testing as a permissible alternative for leak detection, as this is a commonly used practice in 

batch operations.

Response 4.2: The EPA disagrees with the commenter that pressure testing should be 

permitted as an alternative leak detection method. The EPA believes that a successful pressure 

test is not necessarily an indicator that all leaks were found in a CMPU, leaving open the 

possibility that leaks will be missed causing excess fugitive emissions that a facility would not be 

aware of until possibly an unsuccessful pressure test would identify that leak.

5.0 Requirement for Covers or Lids on Process Vessels

Comment 5.1: Four commenters (124, 128, 129, 133) supported the proposed revisions 

to the requirement for covers or lids on process vessels.

Response 5.1: The EPA has finalized the proposed revisions to the requirement for 

covers or lids on process vessels.
December 6, 2012

9

Comment 5.2: One commenter (128) who supported the revisions to the cover/lid 

requirement also requested additional changes to allow for operations in which repeated access 

to the process vessel is necessary. The commenter provided an example of a facility that has 

processes that require repeated access and had installed retractable tank covers on some of their 

process vessels. The commenter noted that the facility found the covers to be prone to 

breakdowns and failures, and that they posed a significant safety concern (due to heavy moving 

equipment) and reduced the number of batches that could be produced (due to the constantly 

moving covers). The commenter recommended that mechanisms that capture or control 

operations similar to covers or lids be permitted, such as a push-pull air circulation system.

Response 5.2: The EPA disagrees with the commenter that providing for alternative 

methods of capture or control of emissions from process vessels is necessary in the final rule. 

The EPA believes that situations in which it is impractical to install a cover or lid, as described 

by the commenter, are fairly rare. For those situations where it is difficult to use a cover or lid, 

the EPA believes that it is more appropriate to address these situations in individual facility 

requests for alternative means of compliance, as described in §63.6(g), rather than in a 

generally applicable nationwide rulemaking.

Comment 5.3: One commenter (121) requested that process vessels should only be 

allowed to vent through a safety device when conditions require it to avoid unsafe conditions and 

that a definition of “safety device” would be appropriate, as consistent with the approach taken in 

the MON. The commenter believed that by including this provision, facilities would be 

precluded from avoiding regulations by routinely venting uncontrolled emissions, as the 

definition of safety device would prescribe under what conditions emissions could be emitted.

Response 5.3: The EPA disagrees with the commenter that a provision for venting 

through a safety device is appropriate in this rule. As finalized, process vessels are required to 

be equipped with a cover or lid at all times except when manual access is necessary, and 

facilities are generally not otherwise permitted to vent uncontrolled emissions under the final 

rule. The EPA notes, however, that facilities are able to avail themselves of an affirmative 

defense for uncontrolled releases that are not permitted and occur as a result of a malfunction.

Comment 5.4: One commenter (139) requested that the EPA exempt process vessels 

operating above 2000 °F from the requirement to install a cover or lid on process vessels in metal 

HAP service. The commenter (141) cited the high costs and potential safety concerns of 

installing a cover on such a vessel.

Response 5.4: The EPA disagrees with the commenter that it is necessary to exempt 

process vessels operating in excess of 2000 °F from the requirement to install a cover or lid for 

process vessels in metal HAP service. We believe situations in which the process vessel would be 

operating at these high temperatures are fairly rare and unique, and we also believe that there a 

potential for increased emissions at higher temperatures. To the extent a source determines it is 

unsafe to use a cover or a lid, the EPA believes that it is more appropriate to address these 

situations in individual facility requests for alternative means of compliance, as described in 

§63.6(g), rather than through a broad nationwide exemption.

6.0 Requirement to Conduct Leak Inspections When Equipment Is 

in HAP Service
December 6, 2012

10

Comment 6.1: One commenter (129) suggests that sources should be allowed to 

postpone leak inspections until the next opportunity to do so when the unit is in organic HAP or 

metal HAP service.

Response 6.1: The EPA disagrees with the commenter that leak inspections should be 

allowed to be delayed until the next opportunity to conduct an inspection while the equipment is 

in organic HAP or metal HAP service. This would provide an indefinite period of time that 

equipment would be permitted to operate without having conducted a leak inspection. The EPA 

believes that it is more reasonable to allow sources to conduct inspections while the equipment is 

in VOC service, as discussed in the preamble to the final rule, as this will provide them with 

more opportunities in which to conduct leak inspections, likely negating the need to delay an 

inspection.

7.0 Applicability of the Family of Materials Concept

All comments related to the Family of Materials concept are addressed in the preamble to 

the final rule.
December 6, 2012

11

8.0 Startup, Shutdown, and Malfunction

Comment 8.1: Two commenters (128, 131) stated that the proposal to eliminate the 

startup, shutdown, and malfunction (SSM) provisions in the proposed subpart revisions is not 

based on an accurate reading of the decision of the D.C. Circuit in Sierra Club v. EPA. The 

commenters state that the EPA’s proposal for the standards 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 the standards for those periods must be developed according to the Clean 

Air Act (CAA) section 112(d) generally achievable control technologies (GACT) process and 

must be proven to be achievable under CAA section 112(d). The commenters add that there is 

ample precedent for the EPA applying a different standard during SSM events, and such a

standard could include a design, equipment, work practice, or operational standard under CAA 

section 112(h).

Response 8.1: The EPA does not claim that the Sierra Club case constrains its authority 

to prescribe unique standards for periods of startup, shutdown, or malfunction. The EPA‘s view 

is that the reasoning of the Sierra Club decision calls into question the legality of source 

category-specific startup and shutdown exemptions in rules promulgated pursuant to CAA 

section 112(d). The EPA also disagrees with the commenters contention that the Sierra Club 

decision addresses in any way the EPA‘s current approach to malfunctions. As explained in the 

preamble to the proposed and final 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. Consistent with Sierra Club, we have issued standards that apply at 

all times, including during malfunctions. The EPA’s rationale for this view is explained in detail 

in the preamble as well.

Comment 8.2: Three commenters (122, 124, 131) recommended that the EPA use its 

CAA 112(d)(5) authority to establish management practices as standards during period of 

malfunction.

One commenter (124) stated that the EPA did not consider malfunctions when 

established GACT for this source category, and as such is obligated to set a standard during 

periods of malfunction. The commenter believed that the EPA has the authority to establish work 

practice or operational standards during malfunctions under CAA section 112(h)(1), or separate 

management practices during malfunctions under CAA section 112(d)(5). The commenter stated 

that these approaches should be used in lieu of the affirmative defense.

One commenter (131) stated 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 emissions standards. The commenter stated that the EPA cannot exclude emissions from 

malfunctions, and then set emissions limits that even the best-performing sources can only 

achieve part of the time. The commenter stated that due to the unplanned nature and variety of 

potential malfunctions, it would be difficult if not impossible for the EPA to gather data and set 

an emissions standard for periods of malfunction. Due to these difficulties, the commenters 

suggest that the EPA either prescribe operational requirements under the authority of CAA 

section 302(k), or promulgate a design, equipment, work practice or operational standard, or 

combination thereof under the authority of CAA section 112(h), where it is not feasible to set or 

enforce an emission limit.
December 6, 2012

12

Response 8.2: The EPA’s rationale for its approach to malfunctions is discussed in the 

preambles to the proposed rule and this final action. As explained in those preambles, 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. There is nothing in 

CAA section 112 that directs the agency to consider malfunctions in determining the level 

“achieved” by sources when setting emission standards. Moreover, while the EPA accounts for 

variability in setting emissions standards consistent with the CAA section 112 case law, nothing 

in that case law requires the agency to consider malfunctions as part of that analysis. As the 

EPA further explained, 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. The same concerns exist whether the Agency 

is establishing numerical or work practice standards.

Comment 8.3: One commenter (128) recommended that, if appropriate, the EPA should 

include the same startup and shutdown standard for metal HAP emissions that exists for 

continuous process vents.

Response 8.3: As no additional data to support the commenter’s recommendation was 

received, the EPA has declined to establish a separate standard for metal HAP process vents 

during periods of startup and shutdown.

Comment 8.4: One commenter (128) recommended that the EPA add language to clarify 

that a malfunction in an air pollution control or monitoring equipment must be recorded only “if 

it caused or may have caused an applicable emission limitation to be exceeded.”

Response 8.4: The EPA agrees with the commenter that records for malfunctions only 

need to be kept if they caused a failure to meet a standard. The EPA has clarified this 

recordkeeping requirement in the final rule.

9.0 Affirmative Defense

Comment 9.1: Two commenters (128, 131) stated that the affirmative defense provisions 

do not cure the EPA’s failure to set emission standards that are achievable during malfunction 

events and are not a substitute for setting achievable emissions standards for these periods. The 

commenters stated that it is not clear what civil penalties the affirmative defense covers, and 

believed 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 relief. The commenters, citing Sierra Club v. Otter Tail Power Co., stated that, as a 

matter of law, injunctive relief may not be available in cases where a civil penalty cannot be 

imposed. The commenters also stated that sources subject to injunctive relief could be required 

to pay the citizen-plaintiff’s attorneys fees even if the source is able to successfully assert the 

affirmative defense, which would not accomplish the EPA’s objective of providing relief for 

violations that meet the conditions of the affirmative defense.

Response 9.1: The affirmative defense applies to civil penalties, including civil 

administrative penalties and penalties under CAA 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 this rule, whether such action is brought by the EPA, a state or local 
December 6, 2012

13

authority or a citizen. The EPA agrees that in some cases, injunctive relief may not be 

appropriate if all the criteria of the affirmative defense have been satisfied. In such cases, 

liability for attorney’s fees is not a real issue. However, some form of injunctive relief may be 

appropriate. The Sierra Club v. Otter Tail Power Co. case cited by commenters is not on point 

and does not undermine the EPA’s ability to limit the affirmative defense to penalty claims. The 

concurrent remedy doctrine provides that where a party's legal remedies are time-barred a 

party's concurrent equitable claims generally are barred. The affirmative defense is not a timebar to civil penalties.

Comment 9.2: Two commenters (128, 131) stated that the EPA should reword the 

“affirmative defense” so that it states that a source would not be deemed in violation of the 

emissions standards for excess emissions or other deviations from the standards, associated with 

a malfunction event, unless the event, and the source’s response to the event, do not meet the 

criteria spelled out in the regulation. When worded this way, it would be more appropriate to call 

the “affirmative defense” something else, such as “alternative standard for SSM events.”

The commenters also stated that if the EPA retains the affirmative defense, the agency 

must modify it substantially so that it does not require the source to prove its innocence. The 

commenters are 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 agency.

Another commenter (126) believed that the EPA should establish a rebuttable 

presumption, rather than an affirmative defense, which would presume that any violation 

occurring during a malfunction not be the facility’s fault unless the EPA can prove otherwise.

Response 9.2: The EPA does not agree with the commenters’ suggested that the term 

“affirmative defense” be revised. We maintain the term accurately reflects the provision. The 

EPA also disagrees with comments that criticize the affirmative defense for shifting the burden of 

proof. The affirmative defense does not require a facility to prove its innocence rather than 

requiring an enforcement authority to prove a violation of the CAA, or otherwise change the 

burden of proof with respect to establishing a violation. The affirmative defense applies to 

penalties and thus is only utilized where a violation has been established. The burden of proof 

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 that 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. It is the source, not 

the EPA (or other party taking enforcement action) that has the information relevant to assess 

whether a particular event qualifies as a malfunction that meets the affirmative defense.

Furthermore, commenters’ suggested approach appears to be similar to the scheme that the court 

vacated in the Sierra Club case, in that there would be no violation unless the enforcing party (the 

EPA or a citizen), established that the event in question was not a malfunction.

Comment 9.3: Four commenters (122, 126,128, 131) stated 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 stated that it should be expected that in 
December 6, 2012

14

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.

Two commenters (122, 126) also stated that the requirement to keep properly signed 

operating logs is outdated since most records are now kept electronically.

Response 9.3: 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.” 

The root cause analysis itself does not necessarily require that the cause be determined, corrected or 

eliminated. However, 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 require 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.

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 experiencing 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 source submitting records electronically should 

exercise due diligence to assure receipt by the EPA and the delegated authority.

Comment 9.4: Two commenters (128, 131) stated that some of the affirmative defense 

requirements are unreasonable, difficult to prove, and subject to varying interpretation and that 

the affirmative defense requirements need to be revised and streamlined to be of practical value. 

The commenters requested that the term “infrequent,” and subjective phrases, such as “if at all 

possible,” “severe property damage,” and “all possible steps,” be removed from the regulatory 

text, as these terms could be subject to different interpretations by regulatory agencies.

Another commenter (124) stated that the affirmative defense criteria are overly 

burdensome, such as the requirement that a facility make repairs as “expeditiously as possible 

when the applicable emission limitations were being exceeded,” and/or unattainable, such as the 

requirements that “[a]ll possible steps were taken to minimize the impact of the excess emissions 

on ambient air quality, the environment and human health” and that a facility minimize the 

frequency, amount, and duration of excess emissions “to the maximum extent practicable during 

periods of such emissions.” The commenter believed that many of the criteria use exaggerated or 

ambiguous language, making it unlikely that sources that experience malfunction events would 

choose to avail themselves of the affirmative defense.

Another commenter (126) stated that if the EPA should choose to keep the affirmative 

defense, several revisions should be made. Specifically, the commenter recommended:

1. Replacing all references to “all” and “any” with “preponderance of evidence.” 
December 6, 2012

15

2. Revising the definition of malfunction to be consistent with that of the General 

Provisions.

3. Allowing the use of the affirmative defense in an action for injunctive relief.

Response 9.4: The EPA believes the affirmative defense criteria are well-defined and will 

assist the EPA and the courts in making reasoned determinations as to the establishment of 

affirmative defenses. The EPA does not believe the terms and conditions of the affirmative 

defense are overly subjective or extreme or need further qualification. The EPA and the courts 

have expertise and experience 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 

Implementation Plans: Policy Regarding Excessive Emissions During Malfunctions, Startup, and 

Shutdown (September 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 9th Circuit (Montana Sulphur & Chemical Co. v EPA, _666 F.3d 1174 (9th 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 consistent 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. As explained above, 

the EPA has determined that including affirmative defense provisions in NESHAP is appropriate 

and reasonable.

Comment 9.5: Two commenters (128, 131) believe the affirmative defense provisions 

should apply to the potential 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 9.5: The EPA is promulgating the affirmative defense for malfunctions only, 

not for periods of startup and shutdown. As explained in the preamble, 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. In contrast, the EPA has determined 

that CAA section 112 does not require that emissions that occur during malfunctions be factored 

into development of CAA section 112 standards. Because startup and shutdown periods are part 

of a source’s normal operations, the same approach to compliance with, and enforcement of, 

applicable emissions standards during those periods should apply as otherwise applies during a 

source’s operations. Further, as explained above, periods of startup and shutdown - but not 

malfunctions - are taken into account when establishing section 112 emissions standards. For 

these reasons, the EPA does not believe it is appropriate to apply the affirmative defense 

provision to startup and shutdown periods. This does not, however, preclude a facility from 

asserting an affirmative defense for a malfunction event that occurs during a period of startup or 

shutdown.

Comment 9.6: Four commenters (122, 126, 128, 131) requested that malfunction 

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.

Another commenter (129) supported allowing sources up to 45 days to submit an 

affirmative defense report, as well as the option to request a 30-day extension.
December 6, 2012

16

Response 9.6: The EPA agrees with the commenters and has revised the reporting 

requirement for asserting an affirmative defense in subpart VVVVVV 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, in a deviation 

report, or in an excess emission report otherwise required after the initial occurrence of the 

violation of the relevant standard, 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.

Comment 9.7: Two commenters (128, 131) stated that the EPA estimate of $2,958 to 

assert an affirmative defense for a malfunction is not credible, appears entirely arbitrary, and is 

remarkably low given the number of different demonstrations and root cause analysis that are 

required of a source. 

The commenters stated it is demonstrated that the EPA believes the affirmative defense 

will effectively be unavailable to facilities, despite their proper design and operation because the 

EPA estimates only 1 or 2 instances of claims of an affirmative defense over a three-year period 

for all the sources subject to the CMAS rule.

Response 9.7: 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 asserting 

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 administrative 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 the 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 preventing 

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.

Owners or operators will often employ such analyses as part of their normal operations, 

because any 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 resolved 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.

We (and the commenters) acknowledge that the complexity of a malfunction event can 

vary. Our cost 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 affirmative defense. As such we 

consider our estimate to be a reasonable estimate for the purpose of estimating the regulatory 

burden on affected sources for these rules.
December 6, 2012

17

Comment 9.8: One commenter (131) stated that the EPA has not justified changing 

conditions that apply to performance testing. The commenter contended that, where the 2009 

final rule referenced the NESHAP General Provisions that required performance tests to be 

conducted based on normal operating conditions of the affected source, the proposed rule 

specified that “operations during periods of startup, shutdown, and malfunction shall not 

constitute representative conditions for the purpose of a performance test,” which would allow 

the EPA to direct a source to conduct performance testing during abnormal operations, such as 

startups, shutdowns, or malfunctions. The commenter stated that the EPA cannot “amend” 

existing GACT 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.

Response 9.8: The EPA notes that the revisions to the performance test requirements 

does not directly require performance testing during SSM periods. However, as noted above, the 

EPA believes that it is important to collect data during all periods including SSM periods, as the 

rule requires when conducting any continuous monitoring. Sources who install continuous 

emissions monitoring systems (CEMS) or other continuous monitoring devices are required to 

operate the monitoring equipment and collect data at all times the process unit is operating and 

at the intervals specified in the rule, except for periods of monitoring system malfunctions, 

repairs associated with monitoring system malfunctions, required monitoring system quality 

assurance or quality control activities and any scheduled maintenance as defined in the unit’s 

site-specific monitoring plan. Sources who conduct continuous monitoring will have HAP and 

other emissions data during SSM periods. Sources that opt to conduct periodic testing will not 

have data collected during SSM periods. A source that experiences a malfunction event may use 

any available information to demonstrate that the source complied with the standard 

notwithstanding the malfunction.

Comment 9.9: Two commenters (128, 131) stated that the EPA has not justified why the 

addition of the new “general duty” language to the standards is necessary, and that the EPA 

should delete the new provisions. One commenter (131) also stated 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).

One commenter (128) was also concerned about the use of the terms “at all times” and 

“minimizing emissions.” The commenter questioned how “at all times” would apply to a CMPU 

that was not operational and whether “minimizing emissions” would require a facility to reduce 

emissions below the level required by the CMAS rule. The commenter also suggested that the 

EPA include the phrase “to the extent practicable” to clarify the extent of the actions required.

Response 9.9: The EPA proposed to revise the CMAS rule in response to petitions for 

reconsideration, and the agency’s authority to propose changes is not limited to changes made 

pursuant to CAA section 112(d)(6) as the commenter states. The EPA, therefore, disagrees with 

the commenter that it lacks the authority to make the changes proposed and that it has not 

justified adding new General Duty language to the standards. The EPA explained in the 

proposal that we were eliminating the reference to 63.6(e)(1)(i) and replacing it with a new 

paragraph in 40 CFR 63.11495(d) that specifies the general duty to minimize emissions applies 

at all times (77 FR 4532). The EPA replaced the reference to 40 CFR 63.6(e)(1)(i) with new 
December 6, 2012

18

language to eliminate language that characterizes what that duty entails during periods of SSM. 

With the elimination of the malfunction exemption, there is no need to differentiate between 

normal operations and malfunction events in describing the general duty. The EPA believes that 

it is also unnecessary to differentiate between normal operations and startup and shutdown 

events in describing the general duty.

The general duty requirement language in 40 CFR 63.11495(d) also differs from 

63.6(e)(1)(i) in that it does not include references to startup, shutdown, and malfunction plans 

because such plans are not required.

Regarding the use of the phrase “at all times,” the EPA notes that if a CMPU were not 

operational, then there would be no emissions emitted and so the commenter’s concerns are 

unwarranted. Regarding the use of the phrase “minimizing emissions,” this language does not 

require that a facility reduce its emissions below that required by the CMAS rule. Also, the EPA 

does not believe that the addition of the phrase “to the extent practicable” to the General Duty is 

necessary.

Comment 9.10: One commenter (128) stated that because the term "affected source" is 

not defined in the CMAS rule, the term "CMPU" should be substituted in the general duty and 

affirmative defense.

Response 9.10: The EPA agrees with the commenter and has revised the final rule to 

reflect the use of “CMPU” instead of “affected source.”

Comment 9.11: One commenter (135) stated that the EPA should not add an affirmative 

defense to the rule on the basis that exposure to formaldehyde can be dangerous and a potential 

risk to human health. The commenter does not believe that allowing a source to avail itself of an 

affirmative defense is a beneficial revision of the rule.

Response 9.11: The EPA initially notes that this rule does not directly regulate the use of 

formaldehyde. The EPA also believes the commenter misunderstands the affirmative defense. 

The affirmative defense can only be employed to relieve a source of penalties. Injunctive relief, 

which would more directly affect future emissions, may still be sought if the EPA or another 

party can demonstrate that such relief is warranted to prevent future exceedances of the 

applicable standards.

.

10.0 Metal HAP Process Vents

Comment 10.1: One commenter (128) supported the proposed clarification that a CMPU 

using only Table 1 metal HAP is not subject to any requirements for wastewater systems or heat 

exchange systems.

Response 10.1: The EPA has finalized the proposed clarification.

Comment 10.2: One commenter (140) requested clarification on the monitoring 

requirements of metal HAP emissions from existing sources.

Response 10.2: The EPA is clarifying that a CMPU required to achieve the emissions 

limits specified in Table 4 of the final rule must also conduct monitoring appropriate to 

demonstrate continuous compliance, as required by §63.11496(f)(3)(i). Examples of monitoring 

sufficient to demonstrate continuous compliance may include a continuous monitoring system or 

periodic monitoring of parameters consistent with operating instructions of the control device 
December 6, 2012

19

supplier (whose parameters must be listed in the monitoring plan, pursuant to 

§63.11496(f)(3)(i)(D)).

11.0 Applicability

Comment 11.1: Four commenters (119, 121, 130, 133) supported the proposed 

clarification as to whether an emission stream that contains a gaseous byproduct is a “process 

fluid” by creating a distinction between liquid streams and process vent streams.

Response 11.1: The EPA has finalized the proposed clarification for liquid stream and 

process vent stream applicability. The EPA notes, however, that it has replaced the term 

“process vent stream” with “continuous process vent or batch process vent” in order to further 

clarify its intent of what a “process vent stream” is.

Comment 11.2: Three commenters (119, 121, 130) requested that the EPA add a 

definition of “process vent stream” in order to help clarify applicability determinations. 

Specifically, the commenters requested a definition that would clarify: (1) whether the 50 parts 

per million by volume (ppmv) threshold applies to controlled or uncontrolled emissions, and (2) 

where within the process the 50 ppmv threshold applies if emissions are routed through a device 

used for both controlling emissions and product recovery. Two commenters (119, 121) believed 

that based on other language used in the CMAS rule, the 50 ppmv threshold would apply to 

emissions prior to entering a control device. One commenter (130) believed that the 50 ppmv 

threshold should apply to emissions upon exiting a recovery device.

Response 11.2: The EPA notes that it has revised the thresholds for process vent streams 

to 0.1 percent by weight, in lieu of the proposed 50 ppmv threshold. In determining applicability 

for process vents, it was the EPA’s intent that the concentration of Table 1 HAP in the stream be 

evaluated at the point of discharge to the atmosphere, or prior to the point of entry into a control 

device if a control device is used. This approach is consistent with the EPA’s definition of 

“uncontrolled emissions,” which bases applicability on emissions after the last recovery device 

but prior to any control device. It is also consistent with the definition of process vent in the 

HON, which is referenced by the CMAS rule in the definition of continuous process vent, as well 

as the definition of metal HAP process vent. In order to make this distinction clearer, the EPA 

has replaced the term “process vent stream” with “continuous process vent or batch process 

vent” in the applicability requirements for the final rule.

Comment 11.3: One commenter (130) questioned whether the EPA expects a facility to 

comply with provisions for liquid streams when the facility is subject to the CMAS rule due to 

process vent streams. The commenter believed that if a facility exceeds the applicability 

threshold for only process vents or only liquid streams, then it should only be subject to the 

applicable requirements for that respective emission point.

Response 11.3: The EPA disagrees with the commenter that facilities subject to the 

CMAS rule due to process vent streams should be exempt from the requirements for liquid 

streams, and vice-versa. The EPA believes that the management practices for liquid streams will 

not cause an unreasonable burden for facilities subject to the CMAS rule if a facility is only 

subject to the CMAS rule due to the presence of Table 1 HAP in a process vent, and vice-versa. 

To the extent that there are facility-specific issues that require clarification, sources should 

contact the applicable delegated state authority or the EPA.
December 6, 2012

20

Comment 11.4: One commenter (122) recommended that the applicability thresholds for 

chromium compounds should be subcategorized based on respective carcinogenicity. The 

commenter believed that this approach would be consistent with the EPA’s Toxic Release 

Inventory, where hexavalent chromium compounds are subject to a 0.1 percent de minimis 

threshold and trivalent chromium compounds are subject to a 1.0 percent de minimis threshold.

Response 11.4: The EPA agrees with the commenter that the applicability thresholds for 

chromium compounds should be different for trivalent and hexavalent chromium. In the original 

final rule, applicability for the 0.1/1.0 percent thresholds was based off of whether a compound 

was listed as a carcinogen by the Occupational Safety and Health Administration (OSHA). As 

specified in 29 CFR part 1910, subpart Z in OSHA’s Toxic and Hazardous Substances list, only 

hexavalent chromium is listed as a carcinogen. As such, the EPA has revised the final rule such 

that the 1.0 percent threshold applies to trivalent chromium and the 0.1 percent threshold 

applies to hexavalent chromium.

Comment 11.5: One commenter (122) requested that a mass-based applicability 

threshold be established. The commenter recommended that a de minimis level of 1,000 lb/yr of 

Table 1 HAP should be adopted, as this would make applicability determinations more 

straightforward and would reduce burden without reducing environmental protection.

Response 11.5: The EPA notes that a de minimis threshold was not an issue that was

open for comment. As such, the EPA is declining to adopt a de minimis threshold for the final 

rule or otherwise respond to specific comments on a de minimis thresholds. See the preamble to 

the October 2009 final rule at 74 FR 56016-56018 and section 3.2 (pp. 3-2 – 3-5) of the October 

2009 response to comment document for additional rationale on the EPA’s decision not to adopt 

a de minimis threshold.

Comment 11.6: One commenter (122) recommended that a concentration exclusion 

should be provided for equipment and vessels that contain organic HAP at concentrations of less 

than 5 percent by weight, which the commenter says would keep the CMAS rule (a GACT rule) 

no more stringent than a MACT standard.

Response 11.6: The EPA notes that a concentration threshold was not an issue that was 

open for comment. In any case, the EPA disagrees with the commenter that equipment 

containing organic HAP at concentrations less than 5 percent by weight should be excluded, as 

the EPA believes that the 0.1/1.0 percent applicability thresholds for liquid streams already in 

place are an appropriate applicability threshold, as those thresholds are the ones used by the 

EPA when determining which area sources of the Urban HAP should be listed for regulation.

Comment 11.7: One commenter (122) requested that fugitive emissions applicability 

should be narrowed so that it is more consistent with other MACT and NSPS rules. Specifically, 

the commenter stated that the EPA should exempt equipment in vacuum service, equipment in 

service less the 300 hours per calendar year, and equipment that is not in organic HAP service 

(defined to mean equipment that is in contact with or contains fluid that is at least 5 percent by 

weight organic HAP) from the leak detection and repair (LDAR) program requirements.

Response 11.7: The EPA notes that applicability of the LDAR program was not an issue 

that was open for comment. In any case, the EPA disagrees with the commenter that the abovedescribed equipment should be exempt from equipment leak requirements. The EPA is requiring 
December 6, 2012

21

that sight, sound, or smell leak inspections be conducted, as opposed to a more stringent 

equipment-based monitoring program (e.g., Method 21). For this reason, the EPA does not 

believe that it is appropriate to exempt certain process equipment from the leak inspection 

requirements. In addition, the EPA believes that it would be more burdensome for sources to 

determine which equipment is in service while conducting sensory monitoring, as it would be 

difficult, if not impossible, to exclude such equipment from sensory inspections due to their 

presence near other affected equipment.

Comment 11.8: One commenter (129) supported the proposed revision to clarify which 

Table 1 HAP are carcinogens and which are not.

Response 11.8: The EPA has finalized the proposed clarification.

Comment 11.9: One commenter (123) supported the proposed revision to exempt lead 

oxide production at lead-acid battery manufacturing facilities that are subject to 40 CFR subpart 

PPPPPP.

Response 11.9: The EPA has finalized the proposed exemption for lead oxide production 

at lead-acid battery manufacturing facilities.

12.0 Compliance Date

Comment 12.1: One commenter (122) requested that, due to the ongoing reconsideration 

process, the required notification of compliance status (NOCS) report should not be required 

until 180 days after the compliance date of the rule (October 29, 2012), as consistent with 40 

CFR 63.9(h), so that facilities have appropriate time to implement the applicable compliance 

requirements.

Response 12.1: The EPA disagrees with the commenter that the deadline for the NOCS 

report should be extended for affected sources. As the EPA has extended the deadline for existing 

sources to comply with the CMAS rule by 90 days, we do not believe that any additional time 

beyond that is needed for facilities to submit their NOCS reports.

13.0 Definitions

Comment 13.1: Three commenters (128, 129, 133) supported the proposed revisions to 

the definition of “in organic HAP service.”

Response 13.1: The EPA has finalized the proposed revisions to this definition.

Comment 13.2: Four commenters (127, 128, 129, 133) supported similar revisions as 

those proposed to “in organic HAP service” be made to the definition of “in metal HAP service.”

Response 13.2: The EPA agrees with the commenters that similar revisions to the 

definition of “in metal HAP service” should be made such that it is similar to the definition of 

“in organic HAP service.” Similar to equipment in organic HAP service, equipment in metal 

HAP service should also be considered to no longer be in service after it has been emptied and 

cleaned to the extent practicable. As such, the EPA has made this revision in the final rule 

amendments.
December 6, 2012

22

Comment 13.3: One commenter (133) supported the proposed revisions to the definition 

of “chemical manufacturing process.”

Response 13.3: The EPA has finalized the proposed revisions to this definition.

Comment 13.4: One commenter (128) requested that the EPA clarify that filter presses 

and other similar equipment (i.e., conveyors and extruders) are not process vessels, as described 

in the preamble to the proposed rule revisions, and that the EPA refer to process vessels in such a 

manner consistent with the definition of “process vessel” in the final rule.

Response 13.4: The EPA agrees with the commenter that equipment such as filter 

presses, conveyors, and extruders are not process vessels.

Comment 13.5: Two commenters (118, 132) requested that the difference between a 

recovery device and a control device be clarified by adding a definition for each.

Response 13.5: The EPA notes that a definition for “recovery device” already exists in 

the CMAS rule. However, in order to help clarify the distinction between recovery and control 

devices, the EPA has incorporated by reference the definition of control device from the HON, 

which states that recovery devices are not considered control devices.

Comment 13.6: One commenter (122) requested that a definition be added for the 

following terms: dense gas system, intermediate change to test method, major change to test 

method, minor change to test method, point of determination, uncontrolled organic HAP 

emissions. The commenter suggests definitions for each, and notes that while not all of the terms 

are used in the CMAS rule, definitions are needed when referencing other subparts from the 

CMAS rule.

Response 13.6: The EPA disagrees with the commenter that a definition is needed for 

dense gas system, as the definition contained in subpart GGG (which is referenced by the CMAS 

rule) would apply since there is no definition in the CMAS rule to override it. The EPA disagrees 

with the commenter that definitions are needed for intermediate change to test method, major 

change to test method, and minor change to test method, as all of these terms are already 

referenced in §63.11503 to their respective definitions in §63.90. The EPA agrees with the 

commenter that a definition of point of determination is needed due to specific references needed 

for the definition to be applicable to the final rule, and has added this definition in the final 

revised rule. The EPA disagrees with the commenter that a separate definition for uncontrolled 

organic HAP emissions is necessary, as the EPA had proposed a definition for uncontrolled 

emissions. However, the EPA has revised this definition in the final rule to be more explicit as to 

how it relates to organic HAP and metal HAP emissions.

14.0 Other/Technical Corrections

Comment 14.1: One commenter (131) stated that the EPA does not have the authority to 

reconsider previously issued GACT standards. The commenter stated that the EPA cannot 

reconsider aspects of previously issued GACT standards unrelated to “development in practices, 

processes, and control technologies,” under CAA section 112(d)(6), including the proposed SSM 

provisions. The commenter also stated that the EPA cannot change its mind about what standards 

are required to comply with CAA section 112(d)(5) nor revisit and redo previously issued 

NESHAP. The commenter stated that even if the EPA had the authority to revise existing GACT 
December 6, 2012

23

standards, it would need to justify the new standards in terms of the criteria for standards under 

CAA section 112(d), which is has not done in the proposed rule. The commenter added that even 

if the EPA had the authority to change the existing GACT standards, it could not reasonably 

make the revised standards effective immediately, noting that CAA section 112(i) allows for a 

compliance deadline of up to three years.

Response 14.1: The EPA disagrees with the commenter that it does not have the 

authority to revisit previously issued NESHAP. In Medical Waste Institute v. EPA, 645 F. 3d 

420, 425-27 (D.C. Cir. 2011), the D.C. Circuit 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). We maintain that similar 

authority exists for standards issued pursuant to section 112(d)(5). The D.C. Circuit’s decision 

in Portland Cement Ass’n v. EPA, 665 F.3d 177, 189 (D.C. Cir. 2011), confirmed that the EPA is 

not constrained by section 112 (d)(6) and it may reassess its standards more often, including 

revising existing floors if need be. Slip op. p. 17. The commenters are thus incorrect that section 

112 (d)(6) provides the exclusive authority to revise existing NESHAP. The EPA also maintains 

that it has authority to reconsider rules and the commenter has not demonstrated that such 

authority does not exist. Consequently, the EPA maintains that it is not barred from 

reconsidering GACT standards.

Comment 14.2: One commenter (122) identified several incorrect or missing references 

in the final rule that should be corrected or added, including: the addition of references to 

§63.996(c)(2)(ii) and §63.998(c)(1)(ii)(E) in §63.11496(g)(5); replacing the reference to 

§63.982(c)(2) with 63.982(c) in Item 1.a of Table 3; removing the reference to §63.11495 in 

Item 1.b of Table 5; revising Item 1.d of Table 5 to reference the correct citations in subpart 

VVVVVV for requirements for offsite cleaning or reloading facilities; and adding a missing 

applicability entry in Table 9 for §63.9(i).

Response 14.2: The EPA has corrected the identified errors in the final rule.

Comment 14.3: One commenter (122) suggested several revisions to improve clarity of 

the final rule, including: adding an example of how to correct emission contributions for 

calculation of the TRE value of combined streams; adding a new Item 3 of Table 3 to clarify the 

requirements for continuous process vents with a TRE > 1.0 but ≤ 4.0; adding a paragraph in 

§63.11496(e) to clarify that the requirements of §63.2450(j) for CEMS do not apply; clarifying 

that the halogenated vent stream requirements also apply to affected storage vessels in 

§63.11497; clarifying that a facility may designate a stream as being halogenated rather than 

calculating the mass emission rate of halogen atoms; clarifying the applicability of §63.8(c)(4) 

and §63.8(g)(5) in Table 9; clarifying in §63.11496(g)(2) that a design evaluation may be used to 

determine initial compliance for sources complying with an outlet concentration emission limit; 

and revising Item 1.a.i of Table 8 to clarify that §63.104(b)(1) does not apply.

Response 14.3: The EPA has made these revisions in the final rule.

Comment 14.4: One commenter (122) suggested that the EPA clarify that the initial 

process condenser initial demonstration requirements of subpart GGG only apply in certain 

circumstances.

Response 14.4: The EPA disagrees with the commenter’s suggested revisions to the 

process condenser initial demonstration requirement. The requirements of §63.1257(b)(8) (as 
December 6, 2012

24

referenced by §63.11496(g)(8) via §63.2460(c)) provide the circumstances under which a 

performance test must be performed for process condensers and further clarification is not 

required.

Comment 14.5: One commenter (122) suggested that the EPA allow facilities to measure 

the caustic strength of the scrubber effluent from halogen scrubbers in lieu of the pH.

Response 14.5: The EPA agrees with the commenter’s suggested alternative and has 

revised the final rule language to allow for measurement of the caustic strength in lieu of the pH. 

The EPA notes, however, that this option is only being made for the measurement of the caustic 

strength of the scrubber effluent, and not for the intake or recirculation tank. This alternative is 

also only being permitted due to the CMAS rule requiring a daily measurement of the pH, as 

opposed to other rules that may require continuous monitoring of the scrubber, in which case 

measurement of the caustic strength may not be appropriate.

Comment 14.6: One commenter (128) stated that the EPA should remove a reference in 

§63.11498(a)(2) to Item 2.c in Table 6, as this item does not appear in the final rule nor the 

proposed rule.

Response 14.6: The EPA has corrected this error in the final rule.

Comment 14.7: One commenter (121) requested that the definition of “batch process 

vent” be amended to include vents from batch operations, not just intermittent flows from 

continuous operations.

Response 14.7: The EPA notes that while the definition of “batch process vent” does not 

preclude streams from batch operations from being considered a batch process vent, the 

definition could be clearer. As such, the EPA agrees with the commenter and has revised the 

definition to specify that it also includes flows from batch operations.

Comment 14.8: One commenter (121) requested that definitions of “batch operation” 

and “continuous operation” be added.

Response 14.8: The EPA agrees with the commenter that definitions of batch operation 

and continuous operation are necessary, as these terms are used in several locations in the final 

rule. As such, the EPA has revised the final rule to incorporate the definition of “batch 

operation” and “continuous operation” from the MON.

Comment 14.9: One commenter (129) believed that the definition of “continuous 

process vent” is confusing since it substitutes words and citations from the HON, and 

recommended that the entire definition be incorporated into the CMAS rule.

Response 14.9: The EPA disagrees with the commenter that the entire definition of 

“continuous process vent” should be incorporated into the CMAS rule. The EPA believes that 

the references and substitutions to the definition of “process vent” in the HON are 

straightforward and generally understood by the regulated community, as this approach is also 

used in the MON.

Comment 14.10: One commenter (128) requested that the EPA allow for hard piping of 

wastewater streams to a point of transfer to onsite hazardous waste treatment, not just to offsite 

hazardous waste treatment.
December 6, 2012

25

Response 14.10: The EPA agrees with the commenter that it is appropriate to allow for 

facilities to hard pipe wastewater streams to a point of transfer to onsite hazardous waste 

treatment, and has made this revision in the final rule amendments.

Comment 14.11: One commenter (128) requested that the definition of hazardous waste 

treatment be revised to clarify that incinerators, process heaters, and boilers that comply with 40 

CFR 63, subpart EEE qualify as hazardous waste treatment units. The commenter also requested 

that this change also be made for 40 CFR part 63, subpart SS, which includes a similar reference 

as the CMAS rule.

Response 14.11: The EPA agrees with the commenter that incinerators, process heats, 

and boilers that comply with subpart EEE qualify as hazardous waste treatment units, and has 

the revised the final rule to reflect this. Regarding the request for a revision to subpart SS, the 

EPA notes that this rulemaking only encompasses subpart VVVVVV, and so a revision to subpart 

SS would be inappropriate at this time.

Comment 14.12: One commenter (133) requested an interpretation regarding the 

exemption for research and development facilities.

Response 14.12: The EPA notes that this was not an issue that was open for comment 

and was addressed in section 3.5.3 (pp. 3-11) of the October 2009 response to comment 

document. The EPA further addressed this issue in the preamble to this final action.