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Response to Comment Document

Nitric Acid NSPS

Part 60 Subpart Ga

May 2012
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Commenters

Docket Number Respondent Affiliation

EPA-HQ-OAR-2010-0750-0086 John Ambrose Rentech

EPA-HQ-OAR-2010-0750-0087 Barbara L. Cabot Dyno Nobel

EPA-HQ-OAR-2010-0750-0088 Chris S. Leason Gallagher and Kennedy on behalf 

of The Fertilizer Institute (TFI)

EPA-HQ-OAR-2010-0750-0089 Adam Diamond Agrium

EPA-HQ-OAR-2010-0750-0090 William E. Flederbach ClimeCo

EPA-HQ-OAR-2010-0750-0091 Russell S. Frye SSM Coalition

EPA-HQ-OAR-2010-0750-0092 Larry D. Fitzwater LSB Industries

EPA-HQ-OAR-2010-0750-0093 Lorraine Krupa Gershman American Chemistry Council 

(ACC)

EPA-HQ-OAR-2010-0750-0094 Jim Schellhorn CF Industries

EPA-HQ-OAR-2010-0750-0095 Desi M. Chari Dow Chemical

EPA-HQ-OAR-2010-0750-0096 Burl Ackerman JR Simplot

EPA-HQ-OAR-2010-0750-0097 Richard S. Vickery and John A. 

Dege

DuPont

EPA-HQ-OAR-2010-0750-0098 William C. Herz The Fertilizer Institute (TFI)

EPA-HQ-OAR-2010-0750-0099 Aruna Prabhala and Kassie 

Siegal

Climate Law Institute, Center for 

Biological Diversity

EPA-HQ-OAR-2010-0750-0100 Melvin E. Keener Coalition for Responsible Waste 

Incineration (CRWI)

EPA-HQ-OAR-2010-0750-0101 Kassie Siegal Center for Biological Diversityaddendum to main comment 

(EPA-HQ-OAR-2010-0750-

0099)

EPA-HQ-OAR-2010-0750-0102 Peter Zalzal Environmental Defense Fund 

(late)

EPA-HQ-OAR-2010-0750-0103 Michael A. Livermore and Jason 

A. Schwartz

Institute for Policy Integrity

EPA-HQ-OAR-2010-0750-0104 Teresa Clemmer Vermont Law School (on behalf 

of EIP, Sierra Club, and NRDC)

EPA-HQ-OAR-2010-0750-0105 Stephenie Moyer Nebraska Department of 

Environmental Quality, Air 

Quality Division, NSPS 

Coordinator
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Comments and Responses

1. NOX Standard

1a. BACT Determinations

Comment 1.1: Commenters (0092, 0094, 0098) urge EPA to consider its recent 

BACT determinations that are set forth in various consent decrees with industry. According 

to the commenter, the proposed standards are based on a BSER which is unsupported by and

more stringent than recent EPA BACT determinations. The commenter asserts that the EPA 

should fully identify and justify the basis for its BSER determination. The commenter states 

that EPA should look to its BACT/LAER clearinghouse and other recently established permit 

limits because, the commenter asserts that NSPS is the statutory floor, and cannot, by

definition, be lower than BACT.

Commenter 0094 states that in addition to the determinations referenced in the 

preamble, EPA recently issued BACT determinations regarding nine of the commenter’s 

nitric acid plants. The commenter states that, effective June 6, 2011, the Consent Decree (see

United States, et. al. v. Terra Industries Inc., et. al., Civil Action No. 11-4038 (U.S. Dist. Ct. 

N. Dist. Iowa)) requires the commenter to reduce NOX emissions from each covered nitric 

acid plant and comply with the following “BACT-equivalent” levels: a short-term NOX limit 

of 1.0 lb/ton; and a long-term NOX limit of 0.60 lb/ton. The commenter states that these 

BACT determinations are inconsistent with and do not support the proposed standards. 

According to the commenter, the recent BACT determinations (and specifically those made 

by EPA) do not support a 0.50 lb/ton standard; rather, they universally identify a 0.60 or 0.61 

lb/ton standard. 

The commenter further argues that the proposed standards should utilize and be based 

on the EPA BACT determinations identified by the commenter and in the preamble. The 

commenter notes that similar information is evaluated for both BACT and BSER purposes. 

Although BACT determinations may include site-specific considerations which are not 

applicable to all nitric acid plants and therefore have to be accounted for in the BSER 

determination, the commenter maintains that the identified EPA BACT determinations do not 

appear to be based on or influenced by any site-specific factors. The commenter emphasizes 

that the EPA BACT determinations universally identified a 0.60 or 0.61 lb/ton standard with 

a number of such determinations being effective as late as June 2011.

Commenter (0094) states the proposed standards are unsupported by and are contrary

to recent BACT determinations. Citing three BACT determinations referenced in the 

preamble, the commenter notes that only one of the referenced BACT determinations 

indicated compliance included periods of startup, shutdown, and malfunction (i.e. Agrium

Kennewick determination). The commenter also cites a June 2011 Consent Decree entered 

into by the commenter and EPA regarding nine of the commenter’s nitric acid plants. In that 

Consent Decree, the commenter notes requirements to meet short-term limits that do not 

apply during periods of startup, shutdown, or malfunction; and to meet a long-term limit that 

is applicable at all times, including periods of startup, shutdown, or malfunction. The 
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commenter reiterates that these determinations show that EPA BACT determinations are 

inconsistent with and do not support the proposed standards.

Response to Comment 1.1: Determining the level of NSPS standards during a 

review of an existing NSPS is an inherently data-driven process. Based on the emissions and 

control technology data available to the agency, we are promulgating an emission standard of 

0.50 lb/ton NOX. The fact that past BACT determinations exist that are less stringent than the 

limit being promulgated in this action does not undermine the process used to develop this 

standard. While BACT determinations and NSPS reviews look at some of the same 

technologies and processes, BACT determinations and NSPS standards are developed under 

two different regulatory regimes and there is no statutory or definitional bar to the level of an 

NSPS being more stringent than a past BACT determination. We note that that both recent 

BACT determinations and this NSPS review have found that emissions well below the 

standard promulgated in subpart G are achievable for new and modified sources.

1b. General Duty Clause

Comment 1.2: Commenter 0091 objects to EPA’s inclusion of a new “General Duty 

Clause” in the nitric acid plant NSPS. According to the commenter, EPA proposes to include 

in the Proposed Standards, without any explanation or even mention in the preamble to the 

Proposed Rule, a provision stating a “general duty to minimize emissions.” The commenter 

notes that the provision is similar to, but differs in important respects from, the “general duty 

clause” of the NSPS General Provisions, 40 CFR §60.11(d), which EPA has relied upon for 

decades and for dozens of other NSPS, including the original NSPS for Nitric Acid Plants at 

40 CFR 60 subpart G.

The commenter urges EPA to justify its promulgation of a new regulation and its 

decision that the existing regulation is insufficient. According to the commenter, the EPA has 

not proposed to amend the NSPS General Provisions, so there could be unresolved conflicts 

between the two provisions, both of which apparently would remain applicable to facilities 

subject to the Subpart Ga Nitric Acid Plant NSPS. The commenter suggests that EPA delete 

proposed section 60.72a(b) from the final rule. If it fails to do so, according to the 

commenter, it would need to re-propose the provision with some explanation of the basis and 

purpose for the provision, to allow the public an opportunity to provide meaningful 

comments, as required by CAA section 307(d)(3). 

According to the commenter, the NSPS General Provisions general duty clause has a 

long history of application and interpretation, which EPA would effectively jettison for 

purposes of the Proposed Standards. The commenter adds that while the General Provisions 

general duty clause states that owners and operators shall maintain and operate an affected 

facility in a manner consistent with good air pollution control practices for minimizing 

emissions “to the extent practicable,” the general duty provision in the Proposed Standards 

contains no such qualification. The commenter asks EPA to compare 40 CFR §60.11(d) with 

proposed section 60.72a(b). The commenter asks that EPA justify its deletion of that very

important phrase. Additionally, if EPA retains a separate general duty provision in the 

Subpart Ga NSPS, the commenter asks that EPA include a sentence making it clear that the 

requirement to operate processes and pollution control equipment to minimize emissions 
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does not require reducing emissions below those allowed by the applicable emission 

limitation, for the reasons described earlier in these comments.

The commenter notes that the general duty provision applies to “any affected source,” 

while the General Provisions general duty clause applies to “any affected facility.” The 

commenter states that the former is not defined in the Proposed Standards nor in the General 

Provisions; the latter is a term defined in the General Provisions and used throughout the 

NSPS regulations. If, in fact, EPA intends for the general duty provision of the Proposed 

Standards to apply to the entire stationary source, and not just the “affected facility,” the 

commenter asserts that the proposed provision goes beyond EPA’s authority under CAA 

section 111.

Comment 1.3: Commenter 0100 suggests that the general duty to minimize 

emissions language of §60.72a(b) is redundant and is not needed in the final rule. According 

to the commenter, the language appears to be similar to the language in §60.11(d). The 

commenter notes that while there are differences between the two paragraphs, both are 

intended to require the affected source to minimize emissions at all times. Since all affected 

sources regulated under 40 CFR Part 60 Subpart Ga are also required to meet the 

requirements in 40 CFR Part 60 Subpart A, the commenter feels that the inclusion of this 

paragraph appears to be redundant. The commenter suggests that if the Agency agrees with 

this suggestion, there are two references to §60.72a(b) that EPA needs to be changed to 

§60.11(d). These are in §60.76a(f)(2) and §60.77a(f)(2).

Response to Comments 1.2-1.3: We agree with the commenters concerning the use 

of “affected facility” versus “affected source.” As a result, the EPA has changed “affected 

source” to “affected facility” within the regulatory text in Subpart Ga.

We have removed the proposed paragraph §60.72a(b) from the final rule. The two 

cross references in §60.76a(f)(2) and §60.77a(f)(2) have been changed to reference 

§60.11(d).

1c. Standard based on 30-day rolling emission rate

Comment 1.4: Commenters (0093, 0095) support EPA’s rationale in choosing a 

long-term rolling emission rate as the appropriate basis for setting the compliance standard so 

as to better reflect actual nitric acid facility operations.

Comment 1.5: Commenters (0092, 0094, 0096, 0098) recommend a 365-day rolling 

average or a 12-month rolling average as the appropriate period to demonstrate compliance.

Comment 1.6: Commenters (0094, 0096, 0098) state that the proposed standards 

are unsupported by and are contrary to recent BACT determinations. Commenter 0094 cites 

three BACT determinations referenced in the preamble, stating that none of the referenced 

BACT determinations included a compliance demonstration period based on a 30-day

emission rate (i. e., Agrium North Bend was based on a 365-day rolling emission rate and 

Agrium Kennewick was based on a 12-month rolling emission rate). The commenter also 

references BACT determinations issued in June 2011 resulting in a Consent Decree 

requiring: a short-term NOX limit of 1.0 lb/ton with compliance based on a rolling 3-hour 
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average (rolled hourly); and a long-term NOX limit of 0.60 lb/ton with compliance 

determined based on a rolling 365-day emission rate (rolled daily). Commenters (0094, 0096,

and 0098) state that as opposed to a 30-day compliance period, such determinations specify a 

365-day rolling emission rate or a 12-month rolling emission rate as the appropriate period to 

demonstrate compliance with the 0.60/0.61 lb/ton standards. Lastly, although several of the 

determinations indicate the 0.60/0.61 lb/ton standards are applicable at all times, the 

commenter indicates that they are based on a one year compliance period, not a 30-day

period. Commenter 0096 supports a 365 day period rather than a 30 day period if the 0.50 

lb/ton limit remains in place for periods of startup and shutdown.

Comment 1.7: Commenter 0092 suggests that for only new, modified or 

reconstructed “dual-pressure” technology nitric acid plants, the NSPS rolling emission rate

should be increased to 365 days with a limit of 0.60 pounds NOX per ton of nitric acid (100% 

basis).

Comment 1.8: Commenter 0097 disagrees with the proposed 30-day rolling 

emission rate. According to the commenter, at least one of the units used by EPA to establish 

the standard apparently could not comply with the new standard since compliance is required 

100% of the time and the EPA analysis shows that they could only achieve compliance 99% 

of the time. To address this, the commenter suggests EPA increase the time period for 

averaging (e.g. 365 day rolling average), increase the numerical standard, or both. 

Response to Comments 1.4-1.8: The EPA disagrees with the commenters who 

recommend a change to the compliance period used for the NOX standard. The standard 

established under Subpart G of Part 60 provided for a 3-hour period during which the NOX

emissions could not exceed the standard of 3.0 lb NOX/ton acid but did not include periods of 

SSM. EPA believes that the change to a 30 day period is reasonable considering that Subpart 

Ga of Part 60 also includes periods of SSM. An emission standard based on the data from the 

test plants calculated as a 365 day rolling emission rate would be lower than the 0.50 lb/ton 

value calculated as a 30 day rolling emission rate. The value for the standard included in this 

NSPS is based on the EPA’s technical evaluation of the emissions data available to the 

Agency. As discussed in Section V of the final rule preamble, that technical evaluation leads 

the Agency to a standard of 0.50 lb NOX /ton acid calculated as a 30 day rolling emission 

rate. Were the Agency to recalculate the standard based on a 365 day emission rate, the value 

obtained would not be the 0.60 lb NOX /ton acid standard recommended by the commenters. 

The standard would likely be substantially lower than 0.50 lb NOX/ton acid if a 365 day

emission rate were used. The 30 day emission rate is a sufficiently long time period to 

account for short term operational variability that may create compliance problems with a 

0.50 lb NOX/ton acid if the standard was based on a short term value, such as the three hour 

rolling emission rate.

The EPA has communicated periodically with industry during the last 3 years, has 

been receptive to any facility-specific emissions data that could be provided, and asked for 

data related to BACT determinations based on reconstructions and modifications on more 

than one occasion. However, EPA did not receive any data from industry during that period 

that could be useful in evaluating the proposed standards in relation to modified and 

reconstructed nitric acid plants other than the data for Agrium North Bend. Furthermore, data 
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received during and after the close of the public comment period for the proposed rule did 

not change the results of our analysis. See Statistical Evaluation of CEMS Data to Determine 

the NOX Emission Standard (Updated Memo for Final Standard), and Analyses of Data 

Received Between Proposal and Promulgation of Part 60, Subpart Ga. See Section V of the 

final rule preamble for discussion of achievability of the standard for the test plants. 

1d. Standard should be changed to a site-specific standard

Comment 1.9: Commenter 0097 suggests that as an alternative to the proposed limit, 

EPA should adopt a technology-based standard, e.g. install SCR, and base the emission limit 

on stack testing (case by case). According to the commenter, the sources could then conduct 

performance tests at typical operating conditions to establish reasonable limits and averaging 

times that would also include startup and shutdown events typical for the type of operation at 

that source.

Response to Comment 1.9: The EPA disagrees that the emission limit should be 

changed to a technology-based, site-specific standard. The standard must be achievable by all 

sources that become subject to this NSPS using best systems of continuous emission 

reduction. Based on the data available to the Agency, we believe the standard included in the 

final rule is achievable by facilities using such systems. See Section V of the final rule 

preamble for further discussion of the level of the standard. CAA 111(b)(5) provides that, 

except for standards set under CAA 111(h), CAA 111 does not require or authorize EPA to 

require that a source use any particular technological system to comply with an NSPS. 

Additionally, the application of design, equipment, work practice, or operational standards 

can be applied when the criteria in section 111(h)(2) are met, which is not the case for nitric 

acid production units. 

2. Test Methods and Monitoring

2a. Accuracy Ranges of Monitoring Equipment

Comment 2.1: Commenter 0097 states that all monitoring systems have inherent 

ranges of accuracies of at least +/- 20%. Thus the commenter asks that the standard be 

established at least 20% above the numerical data provided in the proposal. According to the 

commenter, good operation and maintenance requirements included in General Provisions 

provide adequate certainty that operators are minimizing emissions within the design 

capability of the equipment.

Response to Comment 2.1: We agree with the commenter that all measurement data 

have some inherent uncertainty but we believe that the emissions limit and the averaging 

time adequately account for that uncertainty as well as normal process variability and that no 

additional adjustment is necessary. As with other EPA rulemaking projects, we collected 

emissions data from multiple sources to use in determining an achievable emissions

limitation that represents the best systems for emissions reduction. In the case of the nitric 

acid plant NSPS data collection, we received data collected by CEMS installed on nitric acid 

plants and certified to the applicable performance specification. Those data inherently

represent the measurement uncertainty associated with CEMS measurements. We also 
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applied statistical procedures at proposal to determine the 99th percentile that provided 

additional assurance that we have considered measurement uncertainty along with process 

variability in establishing the limit. This analysis can be found in the memorandum Statistical 

Evaluation of CEMS Data to Determine the NOX Emission Standard (Updated Memo for 

Final Standard). We note that the final rule used the maximum 30-day rolling emission rate 

rather than the 99th percentile. See Response to Comments 5.6-5.7.

2b. Additional Monitoring Equipment to Measure Larger Span 

Comment 2.2: Commenters (0096, 0098) assert that the EPA failed to recognize 

limitations with monitoring equipment during periods of startup and shutdown that 

significantly underestimate emissions during these times.

In order to comply with the current NSPS in Subpart G, the commenters note that 

existing NAPs (including the Test Plants) utilize CEMS to monitor their NOX emissions. 

According to the commenters, these analyzers typically are equipped with only a single span 

range that is calibrated to monitor emissions in the 0-500 ppm NOX range, in compliance 

with Subpart G. The commenter’s members typically experience NOX emissions in the range 

of 2,000 to 5,000 ppm during startup and shutdown events. According to the commenters, the 

Subpart G rules’ span value requirements prevent the NAPs’ CEMS from accurately 

measuring the high emissions during startup and shutdown. According to the commenters, 

the analyzers max out at 500 ppm during these periods. It appears to the commenters that the 

EPA did not consider this issue when evaluating the Test Plants’ CEMS data, and simply

assumed the CEMS data it was analyzing accurately reflected emissions, even during the 

high emissions typical of startup and shutdown. The commenters assert that this assumption 

has the effect of grossly underestimating emissions during startup and shutdown at 500 ppm, 

when such emissions are actually four to ten times higher. The commenters note that this 

effect materially undercuts the EPA’s proposed NSPS because under Subpart Ga NAPs are 

required to measure emissions at all times (including startup and shutdown), and such 

emissions are factored into compliance. Because the EPA’s assumption capped startup and 

shutdown emissions at 500 ppm (due to the limitations of CEMS as calibrated under Subpart 

G), the commenters believe that the EPA’s proposed NSPS does not accurately account for 

actual startup and shutdown emissions. (The commenters note that the Test Plants were 

atypical and the vast majority of NAPs experience very high emissions during startup and 

shutdown that are not accurately measured by a CEMS calibrated in accordance with Subpart 

G.) In order to support any proposed NSPS that requires compliance at all times that is 

achievable (as it must be under CAA § 111), the commenters state that the EPA must 

account, accurately, for all emissions.

In addition to the Subpart G limitations, the commenter’s members and their 

consultants have found that when CEMS are calibrated to a 0-2,000 ppm span value to 

attempt to accurately capture emissions during startup and shutdown (as would be required 

by the proposed NSPS), the NOX monitor does not function accurately at the range that the 

NAPs would be required to maintain at least 99 percent of the time in order to comply with 

the proposed NSPS.
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Response to Comment 2.2: We understand the concern about the possibility that the 

average CEMS concentrations for some facilities in the database may be biased low if the 

CEMS output were detector range limited. The commenters provided no additional data to 

help evaluate to what degree such bias may have occurred. On the other hand, we are aware 

that at least some of the emissions data in the database that the sources provided represent 

startup and shutdown periods with significant spikes in emissions (e.g., a factor of 10) over 

emissions reported for normal production periods. We believe that the database accounts for 

emissions spikes that occur during startup and shutdown periods and that the final NOX

emissions limit established is representative and inclusive of emissions for all periods of 

operation. 

We do agree with the commenter that a CEMS intended to measure emissions across 

a wide range of concentrations must be calibrated for all measurement ranges including 

spikes that may occur during SS periods. In some cases meeting this need will require a dual 

range analyzer with separate sets of calibration gases (and associated span values). We have 

revised the rule to address this concern. Specifically, we have included a second CEMS span

value applicable to dual range systems based on the highest NOX concentration expected 

during startup and shutdown periods.

In response to the commenter’s assertion that the lack of dual span monitors impacts 

the data used in the analysis, the EPA notes that dual span monitors are in use at the Agrium 

North Bend plant. Therefore, the EPA believes that the emissions during startup and 

shutdown were accurately captured for this facility.

We note that periods of startup and shutdown do not constitute a large fraction of 

operating time and are relatively short term events. We also note that the method for 

calculating the 30 operating day rolling emission rate has been clarified to ensure that days 

with only a few hours of operation, that may include a startup or shutdown, do not have an 

artificially exaggerated impact on the 30 operating day emission rate. For the final rule, the 

30 operating day emission rate is calculated by summing the lb NOX/ton of acid values 

calculated each operating hour and dividing by the total number of operating hours in the 30 

operating day period. See Section V of the final rule preamble and the memo entitled 

Statistical Evaluation of CEMS Data to Determine the NOX Emission Standard (Updated 

Memo for Final Standard).

2c. CERMS

Comment 2.3: Commenters (0093, 0095) object to EPA’s proposed requirement for 

facilities subject to this NSPS to install a continuous emissions rate monitoring system 

(CERMS) comprised of a NOX CEMS and a continuous exhaust gas flow rate monitoring 

system. According to the commenters, the EPA has not provided data comparing flow rate 

data to support its requirement for installing CERMS. According to the commenters, having 

to install a flow rate monitoring system would put new or modified facilities at a competitive 

disadvantage, given that the EPA estimates the capital cost of such units to be approximately

$39,000, plus the additional costs of maintenance and testing. In addition, the commenters

believe that the installation of CERMS would likely result in additional facility startups and 
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shutdowns due to additional equipment maintenance and testing requirements, which could 

result in facilities not being able to comply with the proposed emission standard.

Furthermore, the commenter asserts that existing nitric acid facilities that undergo a 

modification may not be able to install a flow rate monitoring system without completely

overhauling existing metering and control systems. The commenters note that there may not 

be space in existing control rooms for the installation of the additional meter, and a new data 

collection system may need to be installed in order to accurately and correctly capture the 

additional data.

Commenter 0093 states that if the EPA finalizes the CERMS requirement, commenter 

0093 supports EPA’s finalization of the proposed performance criteria for such a system, 

which would allow facilities the ability to choose from a range of possible metering systems.

Comment 2.4: Commenter 0092 asks that if the NSPS requires installation of a 

continuous emissions rate monitoring system (CERMS) comprised of a NOX continuous 

emissions monitoring system (CEMS) and a continuous exhaust gas flow rate monitoring 

system, the commenter proposes that the selection of the type of flow rate monitoring device 

(e.g., pitot tube vs thermal resistance flow meters) be at the option of the entity in whose 

name the Title V Air Permit is issued, subject to approval of the regulatory authority issuing 

the permit. 

Comment 2.5: Commenter 0095 suggests as an alternative to the requirement to 

install a flow rate monitoring device, the existing Subpart G allows use of flow measurement 

reading along with CEMS data to establish a conversion factor for the purpose of converting 

monitoring data into units of the applicable standard (lb/ton). The commenter suggests that 

EPA add an option to the proposed Subpart Ga that allows the owner/operator to reestablish 

the conversion factor annually to calculate NOX emissions in the proposed Subpart Ga 

instead of requiring the continuous flow rate monitoring system.

Comment 2.6: Commenter 0097 asks that the EPA provide data to support the 

assumption that a CERMS is more accurate and that the benefits are worth the additional 

cost, especially for small plants. The CERMS approach is a more complex and potentially a 

more unreliable system compared to systems required by the current standard. According to 

the commenter, the CERMS could result in more startups and shutdowns associated with 

maintaining the new equipment. The commenter recommends that the EPA retain the current 

factor method and add the new CERMS method as a second monitoring option. 

Response to Comments 2.3-2.6: The costs for NOX continuous emissions monitoring 

systems were included in the analysis of the economic impact of the initial new source 

performance standard as the commenter noted. The costs for a NOX concentration monitor 

apply to a new source whether constructed under the existing subpart G or under subpart Ga. 

New sources would apply CEMS in much the same manner under subpart Ga as under 

subpart G, so the economic analysis included only the incremental costs for CEMS operation 

over those already projected for new sources under subpart G, i.e., the costs for flow meters. 

We agree with the commenter that the economic analysis for the proposal failed to include all 

of the incremental additional costs associated with implementing the CEMS requirements of 
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the revised rule (e.g., complying with 40 CFR part 60, appendix F procedure 1). We have 

updated the economic analysis for the final rule by including the cost of dual span CEMS and 

annual RATA tests required to certify the CEMS. For more information see Impacts of Nitric 

Acid NSPS Review-NOX (Updated Memo for Final NSPS). Also see Section V of the final 

rule preamble.

The EPA believes that the use of CERMS is warranted. Using a factor established 

during the steady state conditions of a RATA (as allowed by Subpart G) is not necessarily 

representative of real-time operations that fluctuate to meet increased demand, or due to 

ambient temperature changes. CERMS offers instantaneous compliance determinations. With 

the CERMS, the facility will know the flow rate of the emissions stream at any given time. 

When combined with the concentration of NOX and the rate of nitric acid production, realtime compliance can be determined at any time.

3. GHG Regulation

Comment 3.1: Commenter 0099 states that the high degree and certainty of the 

threat to public health and welfare from greenhouse gases such as N2O has been wellestablished; in 2007, the Supreme Court found that GHGs are air pollutants under the Clean 

Air Act (CAA) in Massachusetts v. EPA. The commenter asserts that the EPA echoed that 

finding in 2009 when the agency concluded that N2O and other GHGs “may reasonably be 

anticipated both to endanger public health and to endanger public welfare.” According to the 

commenter, the agency has also acknowledged that N2O emissions are 4.6% of total GHG 

emissions, that nitric acid production is the third largest source of N2O emission in the United 

States, and that nitric acid production contributes 6% to total N2O emissions by the U.S.

Comment 3.2: Commenter 0104 states that according to EPA’s 2009 Endangerment 

and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean 

Air Act (74 FR 66496) six well mixed greenhouse gases, including nitrous oxide, endanger 

public health and welfare within the meaning of the Act. According to the commenter, the 

EPA has stated that global warming endangers public health and welfare in numerous ways.

According to the commenter, EPA has further explained that children, the elderly, 

and the poor are the most vulnerable to these impacts; that greenhouse gas pollution 

endangers both current and future generations; and that the risk and severity of these impacts 

is expected to increase over time.

Comment 3.3: Commenters (0103, 0104) state that N2O is a potent GHG—310 

times more potent than carbon dioxide. Therefore, even when emitted in small quantities, the 

commenters state that this gas can pose a significant threat to public health and welfare. The 

commenters assert that EPA must utilize the opportunity of NSPS review to regulate N2O

emissions from nitric acid plants. Although EPA has some discretion to set standards of 

performance for particular air pollutants under NSPS, the commenters state that its discretion 

is limited.

Comment 3.4: Commenter (0102) asks the EPA to adopt 111(b) standards covering 

N2O emissions. The commenter notes that section 111(b)(1)(A) requires the Administrator to 
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list a category of sources if “it causes, or contributes significantly to, air pollution which may

reasonably be anticipated to endanger public health or welfare.” According to the 

commenter, the Administrator then must publish “standards of performance for new sources 

within such category.” The commenter notes that nothing in the CAA language requires the 

Administrator to make an individualized endangerment finding for each pollutant from the 

listed category. To the contrary, the commenter argues that the definition of “standard of 

performance” is expansive, and does not limit performance standard applicability to the 

pollutant(s) that triggered a sector’s listing under Section 111. The commenter further argues 

that greenhouse gas emissions are air pollutants under the CAA and are therefore subject to 

performance standards issued under Section 111 for listed sectors. As such, according to the 

commenter, EPA must set standards under Section 111(b) for emissions of N2O from nitric 

acid plants.

Comment 3.5: Commenter (0099) notes that as the EPA is aware, the Climate 

Action Reserve has recently finalized its Nitric Acid Production Project Protocol, under 

which nitric acid producers may obtain credits for nitrous oxide reductions that are not 

otherwise required by law. The commenter states that to the extent that a desire to promote 

this voluntary emissions reduction system as a substitute for existing legal requirements 

underpins EPA’s proposal to omit nitrous oxide from the revised NSPS, such a rationale 

would be both illegal and inappropriate. The commenter argues that immediate and assured 

GHG reductions are urgently needed in order to avert truly catastrophic climate change 

damages. According to the commenter, the NSPS program provides a time tested and 

successful mechanism to achieve such reductions, and the EPA may not choose to disregard 

the law in order to facilitate payments to polluters for actions that they would otherwise be 

legally obligated to perform.

Comment 3.6: Commenter (0099) urges the EPA to fully consider emission 

standards that include N2O and to promulgate an emissions limit for both NOX and N2O 

emissions. The commenter notes that merely recommending the use of technology that would 

control N2O emissions rather than requiring it represents both a statutory and policy failure 

by the agency. 

As quoted by the commenter, under §111, the EPA “shall...review, and if 

appropriate, revise” its new source performance standards for each regulated source. 

According to the commenter, EPA has interpreted the term “appropriate” to turn on two 

factors, “(1) the amount of emissions from that source category, and (2) the availability of 

demonstrated control measures.” The commenter states that the EPA acknowledges in its 

proposed NSPS revision that “these nitric acid production units also emit another nitrogen 

compound known as nitrous oxide (N2O), which is considered a greenhouse gas (GHG).” 

According to the commenter, the agency then goes on to say, “technologies such as 

nonselective catalytic reduction (NSCR) are effective in controlling both NOX and N2O.” In 

2010, the EPA prepared a white paper titled “Available and Emerging Technologies for 

Reducing Greenhouse Gas Emissions from the Nitric Acid Production Industry.” According 

to the commenter, the white paper concluded that four different types of control technology

(including primary, secondary, other tertiary controls and NSCR) all effectively

demonstrated in practice that they could reduce N2O emissions. The commenter notes that
Page 13 of 80

the EPA concluded that secondary and tertiary controls were capable of achieving greater 

than 80% reduction of N2O emissions from nitric acid production units. 

The commenter asserts that the EPA must regulate N2O emissions alongside NOX

emissions when revising its NSPS for nitric acid plants. In addition to being a plain violation 

of the statutory text and the agency’s mandatory duties, the commenter argues that the EPA’s 

failure to do so is also arbitrary, capricious, and unreasonable. The commenter further notes 

that the EPA’s failure to propose an emissions standard that includes N2O is particularly 

egregious given the ready availability and low cost of nitrous oxide emissions reductions.

The commenter asserts that the EPA cannot pick and choose with which statutory

obligations it will comply and which it will ignore. The commenter states that the agency

must take into account N2O emissions when establishing new NSPS for nitric acid plants and 

also correct the proposal’s additional shortcomings as discussed above.

Comment 3.7: Commenter (0103) states that EPA is required to “establish Federal 

standards of performance for new sources within [the nitric acid source category].” The 

commenter notes that while EPA will be acting to set emissions standards for N2O during a 

review and not upon a new listing of a category, once it commences a review, EPA must 

“follow the procedure required by this subsection for promulgation . . . .” According to the 

commenter, because cost-benefit analysis is not precluded as a standard for determining 

which pollutants to regulate at promulgation, it is likewise not precluded during review.

Comment 3.8: Commenter (0103) claims that EPA’s justifications for not including 

all pollutants in other rules (Standards of Performance for Coal Preparation and Processing 

Plants; Standards of Performance for New Stationary Sources: Onshore Natural Gas 

Processing) do not apply for N2O. According to the commenter, although some of the same 

technology that limits NOX emissions can control N2O, without a specific standard such 

technology will not be widely implemented. According to the commenter, this is indicated by

EPA reports that show only seventeen percent of plants are using NSCR technology, the only 

technology shown to control the emissions of both NOX and N2O. Likewise, the commenter 

notes a 1987 rulemaking for various manufacturing processes, where the agency decided to 

regulate only the pollutant that was emitted in the greatest quantity. [Standards of 

Performance for New Stationary Sources; Polypropylene, Polyethylene, Polystyrene, and 

Poly(ethylene terephthalate) Manufacturing Industry, (“These pollutants, however, are 

emitted at much lower quantities . . . and, as a result, standards development for this industry

is focusing initially on limiting emissions of VOC.”). ] According to the commenter, this 

approach is improper because quantity of emissions does not necessarily correlate to the cost 

of emissions reductions or the relative net benefits of pollutant reduction. Basing the decision 

on the quantity emitted could be considered unreasonable. Lastly, the commenter notes that 

EPA has looked to Nat’l Lime Ass’n v. EPA to support its argument in favor of discretion; 

however, in that case, the agency cites cost and the unavailability of adequate technology as 

reasons for not regulating certain pollutants.

Comment 3.9: Commenter (0104) feels that EPA has a duty under CAA §111 to 

gather the information needed to develop performance standards for all pollutants emitted in 

significant quantities by a listed industry, including greenhouse gas pollutants.
Page 14 of 80

The commenter notes that if EPA felt it was lacking information concerning nitrous 

oxide control technologies for the nitric acid industry, it should have requested information 

from the industry, particularly from the 14 nitric acid process units in the United States which 

are already using NSCR, a technology which controls both nitrous oxide and NOX. Similarly,

the commenter asserts that EPA should have used its information gathering authority under 

Section 114 to develop the information needed to fully analyze the extent to which nitric acid 

plants emit carbon dioxide, methane, and other greenhouse gases and whether there are any 

technically feasible and economically reasonable methods for controlling such emissions. 

According to the commenter, EPA’s failure to gather the necessary information concerning 

greenhouse gas emissions and controls, failure to conduct the required analysis of greenhouse 

gas emissions and controls, and failure to include any greenhouse gas standards in its 

proposed rule render this rulemaking unlawful.

The commenter states that EPA should have used its information-gathering authority 

under Section 114 to develop information concerning whether the technologies under 

consideration for controlling target pollutants, such as NOX, may have collateral 

environmental effects by increasing emissions of greenhouse gas pollutants. According to the 

commenter, EPA’s technology of choice for controlling NOX emissions—SCR— is known to 

generate additional emissions of nitrous oxide depending on the temperature of the exhaust 

gas. The commenter asks that EPA consider and evaluate this issue before issuing a final 

rule.

Comment 3.10: Commenter (0103) states that the CAA does not expressly lay out a 

decision making framework by which EPA must determine which “air pollutants" get 

standards of performance and which do not. According to the commenter, the Act does 

specify that standards of performance only apply to “air pollutants.” However, according to 

the commenter, N2O satisfies this requirement, as both the Supreme Court and the EPA have 

concluded greenhouse gases, of which N2O is a constituent, are “air pollutants” under the 

CAA. The commenter states that the primary decision making framework laid out in Section 

111 applies only to listing categories of sources: any category which, in EPA’s judgment 

“significantly contributes to air pollution that endangers public health or welfare” should be 

included. According to the commenter, determining which of the pollutants emitted by

already-listed source categories should be regulated, however, need not be based on a finding 

of “significant contribution” and “endangerment.” According to the commenter, nitric acid 

plants have been listed as a source category since March 1971, so EPA need not determine 

that N2O from nitric acid plants significantly contributes to air pollution that endangers 

public health or welfare in order to set a standard of performance for that pollutant. The 

commenter notes that although the definition of “standard of performance” specifies a 

particular emissions standard (i.e., “best,” “cost,” “demonstrated”), it does not specify when

a standard must apply to a particular pollutant. According to the commenter, EPA has some 

discretion to make this determination.

Comment 3.11: Commenter (0103) remarks that to the extent EPA does have 

discretion to select which pollutants to regulate, it must exercise that discretion in a nonarbitrary way. The commenter notes that a cost-benefit framework provides a clear and 

rational basis for choosing the standards of performance for any given pollutant – it should

use this discretion to target pollutants where analysis indicates benefits will justify costs. 
Page 15 of 80

Consistent with the requirements of executive orders, the commenter asks that EPA assess 

the costs and benefits of setting standards of performance for each potential pollutant emitted 

from a source, and then target those pollutants where regulation would maximize benefits. 

According to the commenter, cost-benefit analysis counsels toward setting standards for N2O 

emissions from nitric acid plants. The commenter notes strong evidence that indicates that 

the benefits of regulating N2O will justify the costs. According to the commenter, the benefit 

of regulation of N2O is predominantly the reduction of the negative impacts of global climate 

change. The commenter notes that EPA has previously determined that, GHGs, of which 

N2O is a constituent, pose a danger to public health and welfare. The commenter adds that 

the social cost of carbon can also be used to approximate the benefits of reducing N2O, once 

N2O pollution has been translated into carbon-dioxide equivalent units. According to the 

commenter, the EPA has not prescribed a single monetized number for the social cost of 

carbon; instead it uses four different quantifications, ranging from $4.70 to $64.90 per ton. 

The commenter recommends using the higher numbers. Even using all but the lowest 

possible values, the commenter notes that NSPS for N2O will likely produce benefits that 

exceed costs. According to the commenter, using the central value of $21 would produce

benefits that far exceed the costs of technological upgrades and process changes. According 

to the commenter, the EPA’s recent review of current and emerging technologies available 

for nitric acid plants to reduce N2O emissions indicates that the cost of reduction are 

relatively low. The commenter states that by utilizing technology “demonstrated in practice,” 

nitric acid plants can reduce over eighty percent of their N2O emissions at a cost of $2.32 -

$6.49 for every ton of carbon-dioxide equivalent reduced.

Comment 3.12: Commenter (0103) states that the Proposed Rule itself provides no 

justification for choosing not to regulate N2O. According to the commenter, the Proposed 

Rule acknowledges that some NOX control technologies could also control for N2O and 

concludes that “any controls applied to control NOX emissions would not preclude installing 

cost effective N2O control technologies in the future.” The commenter states that EPA must 

provide a rational basis for its failure to include N2O in the Nitric Acid NSPS within the final 

rule. The commenter notes that no such rational basis may exist, given EPA’s efforts to begin 

to regulate GHG emissions from other sectors, the current availability of control technology, 

and the fact that the benefits of regulation of N2O emissions from nitric acid plants outweigh 

the costs. According to the commenter, failure to include nitrous oxide standards of 

performance for nitric acid plants would be arbitrary and capricious. 

Comment 3.13: Commenter (0104) states that in determining whether to revise an 

existing standard as well as whether to add standards for pollutants not previously covered by 

a performance standard, the commenter notes that EPA has long interpreted the CAA’s 

“appropriateness” determination to turn on two, and only two, factors: (1) the quantity of 

emissions from the source category, and (2) the availability of demonstrated control 

measures.

The commenter asserts that there is a large body of scientific data and evidence that 

would provide a sound technical basis for EPA to establish nitrous oxide controls for nitric 

acid plants. According to the commenter, if EPA had applied its traditional two-factor 

approach, there is only one conclusion it could have reached—that regulation of nitrous 

oxide is appropriate and required. With respect to the first factor, the commenter notes that 
Page 16 of 80

the nitric acid industry emits substantial quantities of nitrous oxide as well as other 

greenhouse gases. The commenter also states that nitric acid plants are the largest industrial 

source of nitrous oxide emissions in the United States. 

With respect to the second factor, the commenter asserts that there are numerous 

well-established and highly effective control technologies available for regulating nitrous 

oxide emissions from the nitric acid industry at a reasonable cost, and there may well be 

feasible strategies for controlling other greenhouse gases as well, as discussed further below.

Comment 3.14: Commenter (0099) states that the EPA’s choice of SCR rather than 

NSCR violates both the letter and intent of section 111. According to the commenter, courts 

have held that the NSPS program “looks toward what may fairly be projected for the 

regulated future, rather than the state of the art at present” since it applies to new plants. 

Similarly, the commenter notes that Congress’ intent in establishing the NSPS process was 

“to induce, to stimulate, and to augment the innovative character of industry in reaching for 

more effective, less costly systems to control air pollution.” Moreover, in determining what 

technologies are “adequately demonstrated” to form the basis for an “achievable” 

performance standard for a particular source category, the commenter asserts that courts have 

held that EPA’s analysis can – indeed should, as appropriate – look beyond facilities within 

the United States. The commenter notes that EPA may base its standards on the application 

of systems of control that are in use in other countries, as well as looking at technology

transfers across industries as the basis for an “achievable” performance standard. According 

to the commenter, the EPA’s failure to even discuss and analyze N2O reductions, let alone 

require them, is an egregious violation of the agency’s statutory duty.

The commenter asks that EPA analyze the potential for both NOX and N2O emission 

controls, and must consider all emissions reductions systems, including those discussed in the 

EPA’s 2010 white paper. The commenter asserts that EPA may not simply ignore an 

important pollutant when revising the standard.

Comment 3.15: Commenter (0104) suggests that nitrous oxide controls for nitric 

acid plants are technically feasible and can be implemented at a reasonable cost. The 

commenter notes that under the Clean Air Act, a standard of performance must be 

“achievable,” and it must “take into account the cost of achieving such reduction and any

nonair quality health and environmental impact and energy requirements” According to the 

commenter, this legal standard is meant to be technology-forcing, and courts have 

“recognized that section 111 ‘looks toward what may fairly be projected for the regulated 

future, rather than the state of the art at present.’” In the case of nitrous oxide emissions from 

nitric acid plants, however, the commenter notes that it is not necessary to look toward the 

future. According to the commenter, EPA has already collected extensive data establishing 

beyond doubt that technically feasible and economically reasonable controls for nitrous oxide 

emissions are available now.

Comment 3.16: Commenter (0104) states that EPA has produced several reports 

listing seven control technologies that are highly effective in reducing N2O emissions during 

the nitric acid process. According to EPA, the commenter notes that secondary and tertiary
Page 17 of 80

controls are the most commonly applied, and “[t]hese technologies are capable of and 

typically achieve greater than 80 percent reduction of N2O emissions.”

The commenter states that it is indisputable that nitrous oxide control technologies are 

technically feasible. The commenter notes that a broad array of controls have been widely

used in the nitric acid industry for a long time, both in the U.S. and abroad. If EPA had 

analyzed these technologies during its review, the commenter believes that EPA would have 

had many different options to choose from in determining which technology constitutes BDT 

for purposes of a nitrous oxide performance standard. Indeed, the commenter notes that EPA 

has made no attempt to argue that nitrous oxide control technologies are not technically 

feasible. According to the commenter, EPA’s passing comment that it has “limited data” 

concerning nitrous oxide controls is simply not accurate in light of its own December 2010 

white paper and its reliance on 24 recent technical papers and other reference materials in 

developing that document. In the absence of any explanation, the commenter does not

understand why EPA failed to include this information in the administrative record and failed 

to propose an emission standard for nitrous oxide. Nevertheless, the commenter asserts that 

EPA’s failure to do so is clearly unlawful.

Comment 3.17: Commenter (0099) states that it is not justifiable for the EPA to set 

an NSPS emission standard for NOX alone. By establishing an emission standard based on 

SCR as the BSER, the commenter believes that the EPA has failed to account for the control 

technology currently being used by existing nitric acid plants. The commenter notes that 

nonselective catalytic reduction and SCR combined with secondary or tertiary catalysts 

control both for NOX and N2O.

The agency asserts several reasons for its determination that SCR is BSER for NSPS 

for nitric acid plants, the chief reason being that “NOX emissions from nitric acid trains using 

SCR are lower than nitric acid trains using NSCR.” However, the commenter believes that

this does not negate the fact that SCR simply does not control for N2O and disregards the 

significant emission reduction NSCR is capable of. For example, while EPA asserts some 

NSCR facilities have shown difficulty in meeting the 0.50 lb NOX/ton limit, the commenter 

notes that the EPA has data from 2 other facilities (Dyno Nobel-Deer Island and JR SimplotHelm) using NSCR that achieved monthly block averages between 0.15-0.36 lb NOX/ton 

acid. According to the commenter, this suggests that NSCR technology is more than capable 

of meeting the agency’s new revised NSPS emissions limit and controlling harmful 

emissions of N2O. 

While we understand the difference between a block average and rolling 

average, the block averages from the Dyno Nobel-Deer Island and JR 

Simplot-Helm plants support the conclusion that the EPA has set an 

insufficiently protective standard for NOX. EPA has not explained why the 

distinction between a block average and a rolling average would be 

determinative or even relevant on this point.] It is important to note that the 

agency itself noted that NSCR is one of several air pollution control 

technologies [that] are effective in controlling NOX emissions. 
Page 18 of 80

The commenter urges the EPA to analyze the potential for both NOX and N2O 

emission controls, and consider all emissions reductions systems, including those discussed 

in the EPA’s 2010 white paper. The commenter notes that the EPA may not simply ignore an 

important pollutant when revising the standard. By not requiring new nitric acid production 

units to control for N2O, the commenter states that the EPA is failing to meet its statutory

obligations, squandering an opportunity to take a substantial step in reducing the amount of 

GHGs emitted into our environment, and leaving the public vulnerable to harmful air 

pollutant for years to come.

Comment 3.18: Commenter 0103 states that the EPA should consider the interactive 

effects that controlling N2O will have on the reduction of NOX. The commenter states that 

the costs and benefits of additional NOX reductions should then be included in any

cost-benefit analysis that EPA conducts with regard to N2O. According to the commenter, 

following this approach will decrease costs and increase benefits of N2O regulation, resulting 

in net public health and welfare improvement. Because of these interactive effects, the 

commenter asks that EPA set a N2O standard at the same time EPA revises the NOX

standard. By setting concurrent standards, the commenter believes that EPA can maximize 

net benefits across both pollutants. In most cases, the commenter notes that it is more cost 

effective for plants to design emissions reductions as part of the initial construction rather 

than adding them to existing plants. Therefore, as new or modified plants are faced with 

added capital expenditures to meet a more stringent NOX standard, the commenter believes 

that it would be cost-effective for them to simultaneously meet a N2O standard, rather than 

requiring expensive capital investment to comply with future N2O regulation.

Comment 3.19: Commenter 0104 points out that the NSCR technologies reviewed 

by EPA were installed twenty years ago or longer, and the agency has not considered the 

potential for NCSR options available today to meet the NOX standard it has proposed at a 

reasonable cost. The commenter feels that it is important for EPA to complete this evaluation 

before promulgating a final rule. If NSCR can meet or exceed the NOX standard EPA has 

proposed at a reasonable cost, the commenter believes that the agency can and should 

simultaneously establish nitrous oxide limits based on this technology.

Comment 3.20: Commenter 0104 states that nitrous oxide controls for nitric acid 

plants are technically feasible and can be implemented at a reasonable cost. The commenter 

states that it is clear that control technologies for N2O are economically reasonable. 

According to the commenter, the EPA sets forth detailed data for three types of N2O 

emission control technology which shows that they are very cost-effective in a 2006 report, 

and reiterated its conclusions in its 2010 white paper. The commenter also notes that the 

European Commission’s BAT analysis for various catalytic N2O reduction strategies showed 

that these technologies are very cost-effective.

According to the commenter, even looking only at N2O reductions (rather than CO2

equivalent), the technologies would be cost-effective. The commenter notes that the low end 

of the range presented by EPA would involve only $620 per ton in capital costs and $43 per 

ton in operating costs. The commenter notes that cost-effectiveness of nitrous oxide controls 

is further demonstrated by the fact that they have been in use, not only in Europe and the 
Page 19 of 80

United States, but also at nitric acid plants in developing countries, such as China, Pakistan, 

Chile, South Africa, South Korea, and Egypt.

According to the commenter, these costs are significantly lower than costs that EPA 

has found reasonable for reducing other pollutants. Accordingly, based on EPA’s own data 

and analysis, the commenter feels that it is beyond dispute that the costs of nitrous oxide 

control technologies are reasonable. Indeed, the commenter states that nitrous oxide controls 

are among the most cost-effective for any type of pollutant. According to the commenter, the 

EPA has made no attempt to argue that nitrous oxide control technologies are not 

economically reasonable, and EPA could not justify such an argument if it tried to do so. 

Accordingly, EPA’s failure to even consider the costs of nitrous oxide controls and its 

accompanying failure to establish any standards for this pollutant, as assessed by the 

commenter, are clearly unlawful.

Response to Comments 3.1-3.20: For the reasons discussed in Section V of the final 

rule preamble, we are not taking any final action with respect to a GHG standard for nitric 

acid plants at this time. The EPA is in the process of gathering and analyzing additional data 

on GHG emissions from NAPUs that will allow the Agency to continue working towards a 

proposal for GHG standards for nitric acid plants. These comments will be considered as we 

develop a proposed rule on a GHG standard for nitric acid plants.

4. Extension Requests

Comment 4: Commenters (0086, 0087, 0088, 0089, 0090) asked the EPA to extend 

the comment period until January 12, 2012.

Response to Comment 4: Due to the short time period between proposal and the 

consent decree deadline for signature of the final rule, an extension of the comment period 

was not granted.

5. Data Issues

Comment 5.1: Commenters (0093, 0095, 0098) state that the NAPs EPA relied 

upon to set the proposed NOX NSPS are not representative of the industry. The commenters 

assert that EPA must establish that an NSPS is achievable under the range of relevant 

conditions that affect the emissions to be regulated. Thus, when using existing sources to 

produce data upon which EPA seeks to rely to support setting an NSPS at a certain level, the 

commenter states that it is incumbent on EPA “to consider the representativeness” of the test 

sources for the industry as a whole, particularly in a case such as this one where EPA’s 

“central argument is that the standard is achievable because it has been achieved (at the 

tested plants).”

Commenter 0098 states that EPA has not given due consideration to identifying and 

evaluating the variable conditions that impact emissions at NAPs. Instead, according to the 

commenter, EPA simply has relied on test results of NAPs that are not representative of the 

industry, and thus, that do not demonstrate that the proposed NSPS is achievable. The 

commenter notes that EPA’s proposed NOX NSPS for NAPs violates the rules set out in 

National Lime. Therefore, the commenter requests that EPA revisit and expand its analysis to 
Page 20 of 80

include consideration of all of the variable conditions in the industry (as well as all of the 

emissions data available to EPA that was not considered), and to create NSPS limits that 

reflect these conditions.

The commenters note that the Test Plants are nonrepresentative of the industry as a 

whole. According to the commenters, two of these NAPs (PCS Geismer 5 and El Dorado 

Nitrogen) are “sister plants” and represent the state of the art, as they were the most recent 

newly constructed NAPs in the industry. According to the commenters, these two NAPs are 

large, modern, dual-pressure process facilities that can achieve low NOX emissions during all 

modes of operation, including during startup, shutdown, and malfunction (SSM) events, 

unlike most NAPs. Further, unlike the rest of the industry, the commenters note that each of 

these Test Plants employ not only SCR, but also includes at least one abatement technology 

in addition to SCR. For example, in addition to utilizing extended absorption and SCR, the 

commenter notes that the Agrium North Bend plant uses HPI as an additional control, which 

is typically not used in the industry. According to the commenters, many producers have 

safety and operational concerns regarding the use of HPI. The commenter states that given 

these concerns, HPI should not be considered BSER, and the data from Agrium North Bend 

is not representative of emission reductions achievable by the industry as a whole. The 

commenters note that all three of the plants utilize the largest forms of extended absorption to 

increase efficiency and, thus, lower NOX emissions, which is not typical in the industry. 

Unlike the industry, the commenters note that all of these facilities can control NOX emission 

during startup and shutdown and remain in compliance with their current permit limits.

According to the commenters, the atypical nature of the Test Plants is most distinct 

when compared to NAPs (typically older plants) that employ NSCR. The commenters note 

that not only do none of the Test Plants use NSCR, but, as EPA long ago recognized, NSCR 

is not an end of the pipe control technology, as some would describe SCR.

According to the commenters, a NAP that employs NSCR is designed differently 

because the NSCR is built into, and is an integral part of, the operation of the NAP, 

particularly in terms of heat balance and energy generation for other parts of the NAP. The 

commenters note that NAPs with an NSCR must keep temperatures elevated in order to 

create the reductive environment within the unit that eliminates both NOX and N2O. In order 

to ensure that temperatures and pressures are adequate for this reductive environment, the 

commenters note that NSCR is placed upstream of the tail gas expander. According to the 

commenters, these expanders will malfunction above the temperatures they are designed to 

handle, and because NSCR reactions are extremely exothermic, any increased NOX

destruction and associated temperature increases related thereto could cripple the expander, 

and thus, the entire NAP. When a NAP with NSCR increases its ability to reduce NOX

emissions, the commenters note that it also results in the increased release of other gases, 

such as CO and NH3. According to the commenters, the Test Plants do not face these 

conditions, limitation, or the ability to modify their operations, or their attendant impacts on 

emissions.

Commenters 0093, 0095, 0098 state that the ICR data provided by the two NSCR 

facilities evaluated by EPA could not achieve the proposed standard. Commenter 0098 states 

that EPA evaluated two separate NSCR facilities: PCS Geismar Train 4 and Agrium 
Page 21 of 80

Sacramento, which demonstrated emissions of 2.41 lb NOX/tHNO3, and 1.29 lb NOX/tHNO3, 

respectively, on a 30-day rolling emission rate. According to the commenters, these results 

led EPA to state that “whether NSCR can meet the levels achievable by SCR over a long 

term, is uncertain.” Yet, the commenters state that EPA nevertheless established the same 

limit for all NAPs – 0.50 lb NOX/tHNO3 – newly constructed, modified, or reconstructed, 

regardless of control technology employed. According to the commenters, there are major 

differences in NAP design, which in turn create a wide range of operating temperatures, 

operating pressures, process configurations, and controls. According to the commenters, all 

of these variables impact plant efficiency and NOX emissions and controls. The commenters 

believe that the diversity in NAP design and operation, and the diversity in the use of control 

and performance of control technologies, does not lend itself to a single, uniform standard. 

Yet, the commenters believe that all of these facts were ignored and not given due 

consideration.

According to the commenters, the EPA’s simple adoption of the Test Plants’ results 

suffers from a potentially fatal assumption that the Test Plants are representative of the 

industry and that newly constructed plants will be able to reach efficiencies similar to those 

of the Test Plants. The commenters state that NAPs are not constructed on a single design, 

but rather are tailored to meet specific production and acid strength requirements. The 

commenters also state that smaller NAPs cannot attain the same levels of efficiency as large 

plants without extremely high incremental costs (relatively speaking). Importantly, the 

commenters note that these costs cannot be offset by increased production. Thus, the 

commenters assert that it is likely that a smaller new plant, designed in a state of the art 

manner, may not be able to meet the proposed NSPS.

Comment 5.2: Commenter (0091) states that if it is possible to gather sufficient 

representative data reflecting emissions during malfunctions, then EPA is obligated to 

consider these data in its calculations of NSPS for steady-state operating conditions (since 

EPA asserts malfunctions are not a separate operating mode). To the extent EPA had access 

to continuous monitoring data for emission units using technology on which the Proposed 

Standards are based that included malfunction periods, the commenter states that EPA could 

have conducted analyses of emissions levels during malfunction events. The commenter 

suggests that even if the continuous monitoring data are for parameters not regulated by the 

Proposed Standards, analysis of monitoring data for those other parameters during 

malfunction events might form a reasonable basis for EPA’s assessment of what standards 

are achieved or achievable during malfunctions. Also, according to the commenter, many 

types of sources are required by many state agencies to submit deviation reports or 

malfunction reports when they experience a malfunction that causes an exceedance of an 

applicable limitation. According to the commenter, the EPA does not appear to have made 

any attempt to obtain and analyze such reports, in order to assess what type of requirement 

might reasonably apply to the subject emission units during malfunctions.

Comment 5.3: Commenter (0098) states that EPA failed to consider other data in its 

possession, selectively sought out CEMS data, and erred in analyzing the CEMS data it did 

evaluate. According to the commenter, the EPA received CEMS data from four NAPs with 

SCR, but claimed to only have received data from three NAPs (the Test Plants it used to 

support the proposed NSPS). Specifically, the commenter’s review of the docket indicates 
Page 22 of 80

that in addition to receiving CEMS data from PCS Geismar 4 and 5, which are referenced in 

the preamble, EPA also received CEMS data for PCS Geismar 3. Despite this, the 

commenter asserts that EPA failed to include an analysis of PCS Geismar 3 (which has an 

SCR) in its calculations to set the new NSPS. The commenter questions why EPA neglected 

to include PCS Geismar 3 in its analysis, and are concerned that the data were omitted simply

because they did not support the 0.50 lb NOX/tHNO3 conclusion.

The commenter analyzed the CEMS data for PCS Geismar 3 using comparable 

methods used by EPA on the three SCR units presented in the preamble. According to the 

commenter, the data were processed from the PCS Geismar 3 raw data, just as the proposed 

Subpart Ga requires. The data, however, did not have any indicators for when the plant was 

operational, so the commenter states that data were excluded when the emission factor was 

less than 0.01 lb NOX/tHNO3, which is a reasonable indicator of periods of nonoperation. 

According to the commenter, the 99th percentile of this data represented emissions of 2.55 lb 

NOX/tHNO3. The commenter provided a figure that showed analysis results for PCS Geismar 

3 would only meet the proposed 0.50 lb NOX/tHNO3 limit about 30 percent of the time, on a 

30-day rolling basis. 

It appears to the commenter that EPA selectively chose to obtain and analyze 

emissions data from sources that had emissions results that supported a preconceived NSPS 

limit, and ignored (in the case of PCS Geismar 3), or refused to obtain and analyze data from 

other NAPs. According to the commenter, this course of action seriously calls into question 

EPA’s conclusion that its proposed NSPS is achievable.

Comment 5.4: Commenter 0098 notes that upon an independent review, it appears 

that EPA’s analyses of PCS Geismar 5 inaccurately calculated (and subsequently reported) 

the plant’s 30-day rolling emission rate. The commenter notes that the same methodology

was used for the Agrium North Bend and El Dorado Nitrogen data. 

According to the commenter, there are two errors present within the EPA’s 

calculations. First, although EPA was provided with CEMS data from PCS Geismar 5 for 

years 2007, 2008 and 2009, the commenter notes that the EPA only analyzed data from 2009. 

An independent calculation by the commenter of all of the data from 2007, 2008 and 2009 

reveals that PCS Geismar 5 emits more than the EPA’s suggested 0.38 lb NOX/tHNO3. The 

commenter provided the results of this calculation (The table provides the percentile 

calculations of PCS Geismar 5’s CEMS data from 2007 – 2009). The figure provided by the 

commenter shows a statistical comparison of PCS Geismar 5’s emissions by averaging 

period for 2007 – 2009. Because EPA incorrectly determined the 99th percentile 30-day

rolling emission rate factor for PCS Geismar 5, the commenter believes that this further calls 

EPA’s proposed NSPS into question. 

Second, while appropriately attempting to exclude data from non-operating days (i.e., 

removing the zeros in its calculations), the commenter notes that the rolling emission rates

the EPA relied upon for PCS Geismar 5 contained non-operating days. According to the 

commenter, this error resulted in many 30-day rolling emission rates consisting of far less 

than 30 operating days and resulted in skewed data that allowed each day in these 

calculations to carry more weight than they otherwise should in a 30-consecutive operating 
Page 23 of 80

day limit. Thus, according to the commenter, the EPA’s calculations do not support the 

Agency’s proposed NSPS in Subpart Ga. The commenter provided an example of this error 

in a table in the text. The table presents a screenshot of the EPA analysis of the CEMS data 

for PCS Geismar 5. The commenter points out that the 30-day rolling emission rate

calculation includes only 22 operating days.

Comment 5.5: Commenter 0098 adds that it appears that EPA failed to apply the 

proposed calculation methodologies in proposed Subpart Ga Section 60.75a to its analysis of 

the CEMS data from Agrium North Bend. Instead, it appears to the commenter that the data 

were calculated using the current Subpart G Section 63.73(b) conversion factor. Based on 

independent tests of member CEMS data, the commenter stated that the current Subpart G 

conversion factor and the proposed calculation equations will yield significantly different 

results. According to the commenter, this further undercuts EPA’s proposed NSPS; EPA 

cannot require compliance with a proposed NSPS based on an untested compliance 

calculation.

Response to Comments 5.1-5.5: The EPA agrees with the commenter that there were 

calculation errors in the analysis of data from PCS Geismar Train 5. These errors have been 

corrected with little to no impact on the analyses (from 0.378 lb NOX/ton acid to 0.375 lb 

NOX/ton acid). The corrected spreadsheet is located in docket EPA-HQ-OAR-2010-0750.

In response to the commenter’s reference to Train 3 at PCS Geismar, the reasoning 

for excluding the train from the analysis was inadvertently left out of the memo. The memo 

(Statistical Evaluation of CEMS Data to Determine the NOX Emission Standard (Updated 

Memo for Final NSPS)) has been updated to include the reasoning, which is twofold. First, 

the train only operated for 15% of the year. The EPA does not consider a year with such a 

low yield to be a representative plant for purposes of the analysis.

Second, this nitric acid plant is not using a best performing SCR. According to a 

telephone conversation between EPA’s Bill Neuffer and Jeremy Richard of PCS Geismar, 

the SCR is located after the gas expander and is thus an atmospheric SCR. According to Mr. 

Richard, this prevents optimal mixing of stack gas and ammonia. He felt that the unit could 

be improved to meet a lower NOX emissions limit on a consistent basis.

Only data from the most recent year was considered in the analyses. Some facilities 

only submitted one year of data so we only considered one year of data from all submissions 

so as not to bias the analysis toward a plant with more data.

In response to the commenter’s reference to the use of hydrogen peroxide injection

(HPI) at Agrium North Bend, the EPA conducted further analyses which show that the limit 

is achievable when the summer months (the period during which Agrium North Bend utilizes 

hydrogen peroxide injection) are excluded from the analyses. The analyses are contained in 

the memo entitled Agrium North Bend Analyses, located in docket EPA-HQ-OAR-2010-

0750. Assuming that ozone season (May through September) represents summer months, the 

analyses shows the maximum 30 operating day emission rate for the year as 0.41 lb NOX/ton 

acid, for the summer months as 0.40 lb NOX/ton acid and for the non-summer months as 0.39 
Page 24 of 80

lb NOX/ton acid. The results of additional analyses are shown in Section V of the final rule 

preamble.

Comment 5.6: Commenter 0098 states that using a 99th percentile calculation in an 

attempt to remove statistically insignificant emission events at the NAPs effectively removed 

these events from their limit evaluation. Although EPA’s calculations are said to include 

startup and shutdown events, according to the commenter, the exclusion of the top one 

percent of these averages effectively removed these events from their limit evaluation. 

Further, the commenter notes that by excluding the top one percent of the data, EPA 

recognizes that one percent of these rolling averages will be in violation of the proposed 

NSPS, yet the NAPs are required to be in compliance at all times. According to the 

commenter, removing the highest readings is the opposite of what is needed to make an 

achievable standard. The commenter requests that EPA correct the statistical analysis by

using an approach that excludes the lowest one percent of the data instead of the highest one 

percent.

Comment 5.7: Commenter 0096 states that according to the proposed calculation of 

the daily mass emissions of NOX, a Nitric Acid Plant must calculate emissions based on the 

number of operating hours in the day. The commenter notes that emissions are calculated by 

summing the daily mass emissions and dividing that by a sum of the daily production values. 

Typically, according to the commenter, startups and shutdowns occur during a portion of a 

day, and startups and shutdowns can occur multiple times per month. According to the 

commenter, utilizing the number of "operating hours per day” vs the number of "hours per 

day” (i.e. 24) skews the daily average (and the 30 day average) by giving more weight to 

higher emissions during the event(s). According to the commenter, the method of calculation 

proposed does not account for hours when there are no emissions so a method of calculation 

that does not include such a bias should be developed.

Response to Comments 5.6-5.7: The EPA has reanalyzed the data using a more 

representative method of calculating the 30 day rolling emission rate that sums all of the 

operating hours rather than the operating days. This method addresses the commenters 

concerns related to weighted emission rates. See Section V of the final rule preamble for 

further discussion of the level of the standard.

Additionally, the EPA agrees with the commenter’s assertion that our analysis 

excluded the top one percent of the data so that one percent of these rolling emission rates

could be in violation of the proposed NSPS for the Agrium North Bend facility using the 

proposed calculation for determining emission rates. However, as shown in the memo 

Statistical Evaluation of CEMS Data to Determine the NOX Emission Standard (Updated 

Memo for Final Standard), all three facilities that use SCR as a NOX control have rolling 

emission rates lower than or equal to 0.50 lb NOX/ton acid at all times using the updated 

calculation method. Also see Section V of the final rule preamble for further discussion of 

the level of the final standard.

Comment 5.8: Commenter 0098 asks why the EPA did not request CEMS data 

from all facilities that have installed CEMS equipment. The commenter had CEMS installed 

at nine NAPs based on a Consent Decree with the EPA, so the EPA should have been aware 
Page 25 of 80

of these NAPs. Yet the commenter did not receive a CAA §114 request for CEMS data from 

these NAPs.

Moreover, the commenter notes that an EPA document from 2009 sets out the NAPs 

with CEMS (which constitute 58 percent of the NAPs in the industry). Despite being well 

aware of what NAPs had CEMS (and what controls were employed at each NAP), and being 

able to obtain relevant data from these NAPs, the commenter notes that the EPA appears to 

have selectively chosen the NAPs from which to request CEMS data during its CAA §114 

request process for this rulemaking.

Response to Comment 5.8: Requesting data from every NAP with CEMS would 

have been an expensive and time-consuming exercise for the nitric acid industry and the 

agency. For that reason, there are limitations on the amount of data that was gathered through 

the CAA §114 request supporting the proposed rule. Sending a Section 114 request to every

nitric acid plant with NOX CEMS was not a viable option for gathering data in a timely

manner. Therefore, the EPA gathered data from the best performing nitric acid plants in the 

United States. The EPA also solicited industry’s input on the selection of these plants.

Also, industry had ample opportunities to voluntarily submit CEMS data, as late as 

the end of the comment period (November 28, 2011) for this NSPS. No additional CEMS 

data were received during the public comment period. Additional data were received shortly

after the close of the comment period and these data did not change the results of our 

analysis. See the memo entitled Analyses of Data Received Between Proposal and 

Promulgation of Part 60, Subpart Ga, for more information on the data received after the 

public comment period. The EPA used the best available data when doing our analysis.

6. Modifications and Reconstructions

Comment 6: Multiple commenters disagree with EPA’s statements concerning the 

lack of modifications and reconstructions of existing nitric acid plants that have occurred 

since 1971.

Commenter 0098 notes that despite new Subpart Ga applying to construction, 

modification, or reconstruction of a NAP, the EPA summarily dismisses the possibility that 

existing sources would undergo a modification or reconstruction triggering Subpart Ga 

applicability and, as a result, the Agency does not evaluate the achievability of the proposed 

0.50 lb NOX/ton acid standard for modified or reconstructed NAPs. Instead, as the 

commenter quotes the EPA, “it is our understanding that [nitric acid producers] would build 

new production units rather than modify or reconstruct existing units.” The commenter is 

unsure how EPA reached this conclusion and requests that EPA explain its reasoning.

Commenter 0094 notes that the EPA incorrectly stated in the preamble that no 

existing nitric acid plant has been modified since 1971. The commenter references a Consent 

Decree that the commenter entered into with the EPA in June 2011 and notes that the 

Complaint filed concurrently with the Consent Decree specifically alleged the modification 

of an existing nitric acid plant. The commenter states:
Page 26 of 80

see United States, et. al. v. Terra Industries Inc., et. al., Civil Action No. 11-

4038 (U.S. Dist. Ct. N. Dist. Iowa) in the Complaint at page 25: “111. After 

publication of the proposed standard of performance for nitric acid production units, 

on or about September of 1992, Port Neal and Terra Industries commenced 

construction of a “modification" of an "existing facility" as those terms are defined in 

the NSPS, 40 C. F.R. §§ 60.2, 60. 14, at Port Neal #1 nitric acid production unit at 

the Port Neal Facility .... The modification increased the acid production capacity of 

the Port Neal Facility ....”

According to the commenter, the EPA has knowledge that existing nitric acid plants 

can and have been modified since Subpart G was promulgated.

Commenter 0098 feels that the EPA’s assumptions regarding the “modification” of 

existing sources that may trigger the new standard will lead to a standard that is arbitrary and 

capricious. The commenter notes that constructing a new NAP is more expensive than 

modifying an existing NAP. Because of the expense of construction materials and equipment, 

the commenter asserts that NAPs are frequently moved throughout the world, and are 

typically upgraded instead of building a new NAP. Thus, from an economic perspective, the 

commenter believes that EPA’s assumption of no modifications or reconstructions of existing 

NAPs appears ungrounded.

Commenter 0093 urges the EPA to recognize that the standard could create a 

disincentive for facility modification due to difficulties in meeting such a standard. 

According to the commenter, the modifications to older nitric acid plants needed to achieve 

the proposed low NOX limits may be technically infeasible and prohibitively expensive as 

they might require reconfiguration of the design of the plant. The commenter notes that these 

facilities may have to make significant changes to ensure that the level of NOX exiting the 

absorber is low enough for tail gas NOX control equipment.

Commenter 0098 states that the EPA must evaluate the achievability of the proposed 

standard to modified and reconstructed NAPs in addition to new NAPs. According to the 

commenter, the EPA is incorrect in its conclusion that existing NAPs will not undergo 

modifications or reconstructions and, as a result, the Nitric Acid NSPS Proposal fails to (1) 

discuss the achievability of the 0.50 lb NOX/ton HNO3 standard for modified or reconstructed 

NAPs, and (2) evaluate the costs associated with such a modification or reconstruction. As 

such, before applying Subpart Ga to modified and reconstructed NAPs, the commenter asks 

that EPA perform the requisite CAA § 111 analysis.

According to Commenter 0098, the NSPS modification trigger is a low hurdle for 

sources and any number of minor changes at an existing NAP could subject it to Subpart Ga. 

The commenter notes that existing NAPs frequently undergo projects that could result in an 

increase in NOX emissions, subjecting the units to Subpart Ga. 

Response to Comment 6: One of the commenters requested that EPA explain this 

statement from the preamble: “it is our understanding that [nitric acid producers] would build 

new production units rather than modify or reconstruct existing units.” 
Page 27 of 80

During multiple meetings in 2009, industry representatives indicated that new nitric 

acid plants were unlikely to be built and that growth in the industry would be managed 

through modifications of existing units. See EPA-HQ-OAR-2010-0750-0022 and EPA-HQOAR-2010-0750-0017. Despite requests for specific information about the plants that had 

been modified, including costs and NOX emissions reductions, no other information was ever 

made available to the EPA prior to proposal.

On June 3, 2010, the EPA had a conference call with The Fertilizer Institute to 

discuss subcategorization of low and medium pressure units from high pressure or dual 

pressure units, especially related to modifications or reconstructions of existing nitric acid 

plants. This conference call is documented in the docket. See email entitled Short Summary 

of Teleconference with TFI re: Subcategorization/Nitric Acid plants from Bill Neuffer, dated 

June 3, 2010.

During the course of the phone call, the EPA asked when the NSPS had been 

triggered by modifications or reconstructions. The response was that there had been no recent 

modifications that triggered NSPS but more information would be gathered. No further 

information on modifications or reconstructions was received by the EPA prior to proposal. 

However, the EPA did have information on the planned construction of a new nitric acid 

plant in Idaho. A permit to construct was issued for Southeast Idaho Energy, which will 

include a new nitric acid plant, in November 2009. With no information on the existence of 

modifications to nitric acid plants during the previous three year period, the EPA was left to 

presume that any future growth in nitric acid capacity would be met through construction of 

new nitric acid plants, like the one at the Southeast Idaho Energy facility.

With respect to the commenters’ statements about the June 2011 consent decree for 

Terra Industries, the EPA disagrees that this information could have been used for this 

rulemaking. The timing of the consent decree makes it highly unlikely that any changes to 

the proposal could have been made and evaluated prior to the court-ordered proposal date.

However, now that some information on modifications has been shared by industry, 

the EPA agrees that the commenters’ concerns about the achievability of the standard by

nitric acid plants that have been modified or reconstructed warranted further analysis. The 

commenters identified a few nitric acid plants that fit those definitions, and we performed

further evaluation of the NOX CEMS data for such plants. Based on our technical evaluation 

of the data, we have determined that the final standard is achievable for modified or 

reconstructed sources. See Section V of the final rule preamble for discussion of the 

achievability of the standard. Also see Section VI of the final rule preamble for discussion of 

the cost impacts of the standard for a modified plant.

7. Subcategorization

Comment 7.1: Commenters (0091, 0093, 0095, 0097, 0098) ask EPA to 

subcategorize nitric acid facilities based on controls, size and/or process, and have different 

requirements for each. The commenters recommend separate standards for small, single 

pressure nitric acid plants.
Page 28 of 80

Commenter 0098 states that under CAA §111, EPA has the authority and discretion 

to create and distinguish among classes, types, sizes, of sources when establishing a NSPS 

for a source category. The commenter believes that the information provided in its member 

survey, the information gathered by EPA through the CAA § 114 process for this 

rulemaking, and the information EPA has gathered during its enforcement initiative 

demonstrates that there are differences between existing NAPs in terms of design, process, 

size, and operation, as well as between newly constructed NAPs, and older NAPs that 

directly and substantially impact a NAPs ability to meet a uniform standard. The commenter 

recommends that EPA evaluate and adopt NSPS limits in three categories: (1) newly 

constructed NAPs; (2) existing NAPs without NSCR that undergo a modification or 

reconstruction; and, (3) existing NAPs with NSCR that undergo a modification or 

reconstruction. While the commenter does not offer specific recommendations regarding 

NSPS limits within these categories, with respect to the latter two categories, the commenter 

refers EPA to its TFI Member Survey, which provides information on all NAPs in the 

industry.

Commenters (0093, 0095) state that if a small nitric acid facility utilizing monopressure needed to make a modification, it would be extremely unlikely that such a facility

would be able to meet the proposed 0.50 pounds of NOX per ton of nitric acid standard, even 

if it was possible to install an SCR. According to the commenters, these facilities may have 

to make significant changes to ensure that the level of NOX exiting the absorber is low 

enough for tail gas NOX control equipment. As such, commenter 0093 recommends that EPA 

collect and analyze data from smaller nitric acid plants utilizing mono-pressure and either 

NSCR or SCR, which reflects the typical nitric acid facility in chemical service. Commenter 

0095 notes that Nitric acid plants that currently utilize mono-pressure would have trouble 

meeting the proposed 30-day rolling emission rate even with similar air emission control 

equipment because the frequency of replacing the precious metal catalyst increases as the 

operating pressure increases, leading to more unplanned shutdowns and startups.

Commenter 0097 points out the differences between the dual pressure units EPA used 

for determining the new standard are fundamentally different from the single pressure 

systems often employed at chemical plants for process use. According to the commenter, 

dual pressure systems would not be economically feasible for smaller capacity plants being 

used to generate intermediate chemicals for use in on-site chemical plants. The commenter 

states that peroxide addition systems would be inherently unsafe for many typical chemical 

plant operations. The commenter notes that peroxide addition may also require high absorber 

pressure (which may not be possible for some existing single pressure plants) and may also 

require a new chiller system (which adds cost). The commenter asserts that smaller plants 

(typical for chemical plants) would not have available steam capacity for SCR preheat (such 

as at EI Dorado) and thus would need to build air heaters for SCR preheat (costs which EPA 

has not considered).

Commenter 0097 asks that EPA have a separate standard for small, single pressure 

nitric acid plants, both new and existing. The commenter states that EPA should evaluate 

data from small, single pressure plants using SCR without peroxide addition to establish a 

standard for new or existing small, single pressure plants. One of the commenter’s existing 
Page 29 of 80

small, single pressure units with SCR is performing in the range of 1.2 - 1.5 lb NOX/ton acid 

on average, including startups and shutdowns.

Comment 7.2: Commenters (0091, 0093, 0095) state that EPA’s assumption that the 

30-day average emission limit that includes periods of startup and shutdown could be 

consistently met is flawed and the commenter believes a higher emissions limit is warranted 

for these operations that are integrated with downstream production process. Commenters

0091 and 0093 state that the Agency assumes that startup and shutdown events will be 

infrequent, and that the 30-day rolling emissions will fall below the proposed emission 

limitation. According to the commenters, large commercial nitric acid producing plants may

have very few startups and shutdowns, but smaller plants integrated with downstream 

production processes incur frequent startups and shutdowns, and therefore will have higher 

30-day rolling NOX emissions. The commenters note that more frequent startups mean more 

thermal cycling of high temperature equipment, which leads to shorter equipment life and 

failures, which in turn can increase the load on the NOX control equipment. Commenter 0093 

notes that EPA has suggested HPI as a way to reduce emissions during startup, during some 

cases, but it may not be a viable option for chemical plants where the addition of peroxide 

could negatively impact acid quality for process use and pose additional safety hazards 

during downstream processing. Commenter 0091 understands that CEMS data that was 

submitted to EPA for the development of the Proposed Rule confirms this distinction.

According to the commenter, EPA cannot, under section 111, promulgate an NSPS 

applicable to such smaller nitric acid plants that are integrated with downstream production 

processes based on an assumption of infrequent startup/shutdown that is inaccurate for that 

type of facility.

Comment 7.3: Commenter 0097 disagrees with EPA’s assertion that modified or 

reconstructed sources will be able to meet the proposed limit. The commenter states that 

facilities with existing small, single pressure units (if reconstructed or modified) which 

currently employ SCR (BSER) without the appropriate additional process technology (e.g. 

dual pressure design) may be required to install a new dual pressure unit (versus a retrofit) in 

order to comply.

Response to Comments 7.1-7.3: EPA disagrees that subcategorization is required or 

appropriate. As described in Section V of the final rule preamble, we have decided to 

promulgate a limit of 0.50 lb/ton based on our technical evaluation of the data available to 

the agency. The commenters have not offered data that would support changing the emission 

limit beyond this 0.50 lb/ton level. The data also do not support establishing a subcategory.

We reviewed data submitted by the American Chemistry Council (ACC) after 

proposal. The NOX emissions were higher than the final emission limit. However, none of 

the data were from nitric acid plants controlled by BSER. Therefore, these data have not 

impacted the level of the standard in the final rule. More details are contained in Docket 

Number EPA-HQ-OAR-2010-0750. See Teleconference with American Chemistry Council 

on January 11, 2012, and Analyses of Data Received Between Proposal and Promulgation of 

Part 60, Subpart Ga.
Page 30 of 80

The EPA disagrees that information from the EPA’s enforcement initiative or the TFI 

Member Survey must drive the level of the standard in the nitric acid NSPS review. 

According to the meeting minutes from a meeting with TFI on June 30, 2009, EPA staff

stated that “[the enforcement initiative] focused on the high emitters and would not likely

provide the information needed for NSPS review.” Section 111 of the CAA requires that 

NSPS reflect the application of the best system of emission reductions which (taking into 

consideration the cost of achieving such emission reductions, any nonair quality health and 

environmental impact and energy requirements) the Administrator determines has been 

adequately demonstrated. Focusing on the high emitters does not demonstrate the best system 

of emission reductions.

In order to be useful for EPA’s analysis, the TFI Member Survey should have 

included facility-specific information, which was never supplied. A summary of findings 

across the surveyed facilities does not demonstrate the best system of emission reductions.

The Agrium North Bend nitric acid plant, which is described further in Section V of 

the final rule preamble, is a small single pressure operation which has also been modified or 

reconstructed within the past 10 years. Based on the re-analysis of the CEMS data for this 

modified or reconstructed source and other single pressure operations supplied by ACC, we 

conclude that 0.50 lb NOX/ton acid is achievable for nitric acid plants that undergo 

modification or reconstruction. See memos entitled Statistical Evaluation of CEMS Data to 

Determine the NOX emission Standard (Updated Memo for Final Standard), Agrium North 

Bend Analyses, and Analyses of Data Received Between Proposal and Promulgation of Part 

60 Subpart Ga.

We have updated our cost analysis to include the costs for installation of an SCR if an 

existing facility is modified or reconstructed and triggers NSPS subpart Ga. The capital cost 

for an SCR installed was estimated to be roughly $2,700,000 ($370,000 annualized cost, 

assuming a 20 year capital recovery period). This facility achieved emissions reductions of 

nearly 300 tons of NOX per year. The cost effectiveness for the addition of this control device 

was roughly $1,200 per ton of NOX. The costs for installation and operation of this control 

device are reasonable and cost effective. See memo entitled Impacts of Nitric Acid NSPS 

Review-NOX (Updated Memo for Final NSPS). See also Section VI of the final rule 

preamble. 

According to the CEMS data received from the Section 114 questionnaires, JR 

Simplot in Helm, California, Dyno Nobel in Deer Island, Oregon, and Coffeyville Resources 

in Coffeyville, Kansas are achieving low NOX emissions. All of these plants are 

monopressure nitric acid plants. The JR Simplot and Dyno Nobel Deer Island nitric acid 

plants are controlled by NSCR and the Coffeyville Resources nitric acid plant is controlled 

by SCR. Due to the low emissions from these monopressure nitric acid plants, 

subcategorization is not justified for this final rule.

The use of hydrogen peroxide injection at Agrium North Bend is summarized in 

Response to Comments 5.1-5.5. The full analyses are discussed in detail in the memo entitled 

Agrium North Bend Analyses.
Page 31 of 80

With regard to the cost issues raised by the commenters, refer to Response to 

Comments 10.4-10.9 and the memo Impacts of Nitric Acid NSPS Review—NOX (Updated 

Memo for Final NSPS). See also Section VI of the final rule preamble for the estimated cost 

impacts of the final rule. The EPA considers these costs to be reasonable and supported by

recent NSPS for other categories.

8. Startup, Shutdown, and Malfunction

8a. Numerical emission limitations should not apply during SSM

Comment 8.1: Commenter 0091 asks that EPA justify applying the same emission 

limitations during startup and shutdown as during normal operations. The commenter states 

that there is ample precedent for EPA applying a different standard during SSM events. 

According to the commenter, both prior to the Clean Air Act Amendments of 1977 (which 

defined “emission limitation” and “emission standard” to be something that “limits the 

quantity, rate, or concentration of emissions of air pollutants on a continuous basis”) and 

since that time, EPA has not required sources to meet NSPS emission limitations under CAA 

section 111 established for normal operations, during SSM events. See 40 C.F.R. § 60.8(c). 

The commenter notes that there is nothing in the legislative history of the 1977 amendments 

to the CAA that suggests Congress intended to overturn that practice. Rather, the commenter 

contends that the “continuous basis” language inserted in 1977 related to a debate in 

Congress about whether sources should be allowed to use temporary or intermittent pollution 

control technologies. The commenter notes that legislative history indicates Congress was 

aware that alternative emission limitations might at times be necessary, even though the 

emission limitations were established based on the capability of “continuous controls” like 

scrubbers. The commenter also notes court decisions both before and after the Clean Air Act 

Amendments of 1977 that have affirmed the appropriateness of including special SSM 

provisions in standards issued under section 111. According to the commenter, it is clear that 

the D.C. Circuit’s Sierra Club decision does not compel or even support EPA’s adoption of 

the SSM provisions (or lack thereof) in the Proposed Rule. The commenter notes that the 

decision said nothing about whether EPA could apply different emission limitations during 

SSM events, nor did it consider whether EPA could address SSM events through work 

practice standards.

Commenter 0091 states that an emission limitation that applies during SSM events 

does not meet the requirement of CAA section 111(a) that EPA establish “standards of 

performance” under that section that are “achievable” with the “best” emission control 

technology, “taking into consideration the cost of achieving such emission reduction, and any

nonair quality health and environmental impact and energy requirements” that has been 

“adequately demonstrated” if in fact EPA has not demonstrated that the limitation is 

reasonably “achievable” with available technology during malfunction events.

The commenter asserts that the plain-language reading of the applicable statutory

requirements is echoed by extensive case law. The commenter states the following:
Page 32 of 80

The Weyerhaeuser Co. v. Costle decision EPA cites in the preamble to 

the Proposed Rule, 590 F. 2d 1011 D.C. Cir. 1078), does not support 

EPA’s position. See 76 Fed. Reg. 63,883 col. 3. In that case, the court 

was discussing a “technology forcing” standard, rather than one, like 

NSPS, that is to be based on what has already been demonstrated to be 

achievable. Also, the SSM events that EPA acknowledges are expected 

to occur at sources subject to the Proposed Standards are a far cry from 

the “’uncontrollable acts of third parties,’ such as strikes, sabotage, 

operator intoxication, or insanity” that the Weyerhaeuser Court was 

considering in the passage quoted by EPA, see id. Industry is not 

requesting that EPA establish NSPS that can be met even during those 

exceedingly unusual types of events. Perhaps most importantly, the 

Weyerhaeuser decision came long before NRDC v. EPA, 859 F.2d 156 

(D.C. Cir. 1988) which, as noted above, affirmed the need for an upset 

provision to address circumstances where compliance with effluent 

limitations is impossible through no fault of the permittee, and which 

endorsed Marathon Oil.

Commenter 0091 provides several options for NSPS that would apply during 

malfunction events:

 The commenter suggests EPA establish an emission limitation that applies at all times, 

but that has an averaging time of sufficient duration that short, infrequent spikes in 

emissions due to malfunctions would not cause the source to exceed the emission 

limitation (while at the same time ensuring that the source does not operate in a way that 

causes frequent, lengthy excursions above the normal controlled emission rate).

 The commenter suggests EPA use the flexibility accorded by CAA section 302(k) to 

address emissions during malfunction events through operational requirements rather 

than by applying the same limits on pollutant concentrations in exhaust gases that apply

during normal operations. According to the commenter, EPA could have concluded that it 

has grounds to exercise its authority under CAA section 111(h) to promulgate a design, 

equipment, work practice, or operational standard, or combination thereof, because it is 

not feasible to prescribe or enforce an emission standard. The commenter also notes that 

EPA might use several of these approaches in combination.

According to commenter 0091, there is no indication in the Proposed Rule that EPA 

gave much, if any, consideration to these types of options. In short, the commenter believes 

that there are ample reasons to reject EPA’s conclusory assertions that it cannot take 

malfunctions into account when setting NSPS for Nitric Acid Plants. According to the 

commenter, EPA’s failure to evaluate these options thoroughly renders the Proposed Rule 

arbitrary and requires EPA to develop a new proposal.

Commenters (0091, 0092) state that EPA offers no explanation of its contradictory

position that, even though it believes malfunctions are not a distinct operating mode, 

emissions during malfunctions should not be used to characterize the source’s operating 

mode, which should be characterized only by a source’s emissions during normal operations, 
Page 33 of 80

and not “account for the innumerable types of malfunction events in setting emission 

standards.” According to the commenters, asserting that malfunctions are part of normal 

operations, but then excluding emissions during malfunctions when determining emission 

limitations for the source’s operation, makes no sense.

Commenter 0091 notes that the EPA acknowledges that properly designed and 

operated equipment will sometimes exceed emission limitations based on steady-state 

operation due to malfunctions. According to the commenter, the operators of these processes 

and equipment must treat malfunctions as very distinct events from steady-state operations, 

depending on the severity of the malfunction, requiring anything from shutdown of the unit 

to emergency fire response actions. In addition, the commenter notes that it is often 

impossible to gather emission data during malfunctions – either for standard-setting or for

compliance-demonstration purposes. Malfunctions are by definition unexpected, so 

according to the commenter, it is not possible to plan to have test equipment in place to 

measure emissions when one occurs. Even if test or monitoring equipment is in place, the 

commenter notes that emissions during malfunctions often are not routed to a stack where 

they can be measured, and upsets during stack testing invalidate the test results under EPA’s 

approved test methods.

Rather than supporting EPA’s decision to ignore the fact that SSM events can lead to 

higher emissions even at well-operated facilities with the best control equipment, commenter 

0091 notes that these findings should lead EPA to its authority under CAA section 111(h) to 

prescribe alternative design, equipment, work practice, or operational standards where it is 

not feasible to set or enforce a numerical emission limit. According to the commenter, EPA 

cannot rationally defend its articulated view that applying the concept of “best system of 

emission reduction which ... has been adequately demonstrated” is inconsistent with a source 

experiencing a malfunction. The commenter notes that EPA ignores that there are work 

practices – such as monitoring of operating parameters to identify a malfunction and stopping 

or cutting back the process accordingly – that represent the best practices for minimizing 

emissions during a malfunction. While the measures that represent these best practices will 

depend on facility-specific issues, such as process design, pollution control train, and other 

factors, the commenter notes that they are nonetheless the “best system of emission reduction 

which ... has been adequately demonstrated.”

Commenter 0091 states that in the preamble to the proposed rule, EPA does not say

that it is precluded from adopting different emission limitations that would apply during 

startup and shutdown periods. Rather, the commenter notes that EPA has acknowledged that 

NOX emissions are higher during startup and shutdown than during normal operations, but 

EPA “believe[s]” that sources can meet a 30-day rolling emission limitation that is based on 

performance achievable during normal operations, even if there are startup or shutdown 

events during those 30 days, because startup and shutdown events at nitric acid plants are 

“relatively short,” meaning “generally” only a few hours. 

As incorporated by reference, commenter 0091 argued in docket EPA-HQ-OAR-2009-

0559 as follows:
Page 34 of 80

The commenter stated that EPA incorrectly claimed that its authority to 

prescribe unique standards for SSM periods is constrained by Sierra Club v. 

EPA, 551 F.3d 1019 (D.C. Cir. 2008). The commenter stated that EPA has 

failed to account adequately for emissions that occur during SSM periods. The 

commenter argued that the D.C. Circuit’s Sierra Club decision manifestly is 

not binding on EPA’s establishment of performance standards for SSI units 

under CAA sections 111 and 129. The commenter contended that the Sierra 

Club decision interpreted section 112, not section 129 (which incorporates by

reference section 111), and pointed out that this interpretation is not merely a 

technical distinction. The commenter referred to the language that the D.C. 

Circuit considered dispositive in interpreting EPA’s standards-setting 

authority under section 112 (the statement in the definition of emission 

limitation and emission standard that it limits the quantity, rate, or 

concentration of emissions of air pollutants on a continuous basis) as having 

been in the statute since 1977. The commenter pointed out that since 1977, 

EPA has exempted emissions during SSM events from compliance with NSPS 

under CAA section 111 (referenced 40 CFR §60.8(c)). The commenter argued 

that congress enacted the continuous basis language in section 302(k) 

knowing that EPA’s emissions standards under section 111 exempted SSM 

periods, and pointed out that there is nothing in the legislative history of the 

1977 amendments to the CAA that suggests congress intended to overturn that 

practice. The commenter referenced 551 F.3d at 1027, citing Kamp v. 

Hernandez, 752 F.2d 1444, 1452 (9th Cir.1985), and stated that it had nothing 

to do with limitations applied during SSM nor with EPA’s established practice 

of exempting excess emissions during SSM events from its performance 

standards. 

Also, as incorporated by reference, commenter (0091) argued that the Sierra 

Club decision does not prevent EPA from adopting emission standards for 

SSM periods that are different from those required during periods of normal 

operation. The commenter stated that while it is true that a blanket exemption 

from any standard may be inconsistent with the Sierra Club holding, the 

opinion does not prohibit EPA from applying different, even non-numerical, 

standards during SSM events from those standards that apply during steadystate operations. The commenter stated that the Sierra Club decision only 

rejected EPA’s assertion that it had discretion to decide not to impose any

emission standard whatsoever during SSM periods (referenced id. at 1027-28, 

1030); and in fact, Sierra Club acknowledged that the definition of emission 

standard in §302(k) indicates that any one standard need not apply at all times.

Also as incorporated by reference, commenter 0091’s statement from docket EPA-HQOAR-2010-0600 is summarized as follows:

According to the commenter, the proposed SSM provisions are not required in 

order to be consistent with Sierra Club v. EPA. The commenter notes that 

EPA suggests that its treatment of excess emissions during SSM events in the 

Proposed Standards is appropriate, perhaps compelled, in order to make the 
Page 35 of 80

standards “consistent with” the D.C. Circuit’s decision in Sierra Club v. EPA, 

551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (2010), which 

vacated the exemption for excess emissions during SSM events contained in 

the 40 C.F.R. part 63, subpart A General Provisions for emission standards for 

hazardous air pollutants under CAA section 112. See, e.g., 75 Fed. Reg. at 

65,074 col. 2; 65,075 col. 3 - 65,076 col. 1. However, according to the 

commenter, the D.C. Circuit’s Sierra Club decision does not, however, 

compel or even support EPA’s adoption of the Proposed SSM Provisions.

According to the commenter, the Sierra Club decision did not say that the 

same emission limitations that EPA has derived for normal operations must 

also apply during SSM events. According to the commenter, there is ample 

precedent for EPA applying a different standard during SSM events. The 

commenter notes that the language that the D.C. Circuit considered dispositive 

in interpreting EPA’s standards-setting authority under section 112 — the 

statement in the definition of “emission limitation” and “emission standard” 

that it “limits the quantity, rate, or concentration of emissions of air pollutants 

on a continuous basis” — has been in the statute since 1977. Throughout that 

time, the commenter noted that EPA has not required sources to meet NSPS 

emission limitations under CAA section 111 established for normal operations 

during SSM events. See 40 C.F.R. § 60.8(c). In fact, the commenter noted that 

Congress enacted the “continuous basis” language in section 302(k) knowing 

that EPA’s emissions standards under section 111 exempted SSM periods. 

According to the commenter, there is nothing in the legislative history of the 

1977 amendments to the CAA that suggests Congress intended to overturn 

that practice.

According to the commenter, the Sierra Club decision did not address whether 

EPA could use a “design, equipment, work practice or operational standard,” 

as authorized under CAA section 112(h) and included in the definition of 

“emission limitation” and “emission standard” in CAA section 302(k), in lieu 

of a numerical emission limitation during SSM events. According to the 

commenter, EPA told the Court that the General Provisions SSM exemption 

struck down in Sierra Club was not an alternative standard based on that work 

practice, etc. authority. See 551 F.3d at 1028. Indeed, the commenter noted 

that EPA argued in that case that section 112(h) was irrelevant to its authority

to exempt excess emissions during SSM events. Id. at 1030 (Randolph, J. 

dissenting). 

Thus, the commenter stated that EPA cannot hide behind the Sierra Club 

decision as a justification for ignoring the inability of even the “best 

performers” to achieve during SSM events the emission limitations EPA has 

established for normal operations.

Response to Comment 8.1: For the reasons stated below, the EPA disagrees that 

there should be a separate NOX standard during startup and shutdown.
Page 36 of 80

The EPA does not claim that the Sierra Club case constrains its authority to 

prescribe unique standards for SSM periods or directly addresses the legality of SSM 

exemptions for section 111 standards. The EPA’s view is that the reasoning of the 

Sierra Club decision calls into question the legality of source category-specific SSM 

exemptions in rules promulgated pursuant to section 111. The EPA‘s approach to 

malfunctions is consistent with section 111 and is a reasonable interpretation of the 

statute.

The EPA disagrees with commenter’s suggestion that the existence of an SSM 

exemption in rules implementing 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. The commenter fails to cite 

legislative history or any other evidence supporting that Congress was aware or 

approved of that exemption. 

The EPA also disagrees with the commenter that contends that the Sierra Club 

decision addresses in any way the EPA’s current approach to malfunctions. 

Consistent with Sierra Club, we have issued standards that apply at all times, 

including during malfunctions.

8b. The standard is not achievable

Comment 8.2: Commenter 0091 notes that the EPA ignores the undisputed existence 

of malfunctions even at best-performing sources, and claims falsely that the best-performing 

sources “achieve” emission levels that they undisputedly do not achieve part of the time. 

Since the EPA describes malfunctions as being sometimes unavoidable or “not reasonably

preventable,” despite proper design and maintenance of equipment, the commenter believes 

there is no basis for the EPA’s conclusion that malfunction events are not representative of 

best-performing sources. According to the commenter, the EPA must acknowledge the fact 

that those sources nevertheless experience malfunction events, rather than assume those 

emissions away.

Commenters (0091, 0095, 0098) state that the 30-day rolling compliance period does

not properly account for the increased emissions at startup and shutdown. 

Commenter 0098 notes the EPA’s use of Test Plants that can avoid the increased 

emissions at startup and shutdown due to their atypical design, process, operation, and 

emissions controls to set a 30-day compliance period thoroughly undercuts the EPA’s 

reasoning when considered in light of the entire industry that the vast majority of NAPs 

cannot avoid such increased emissions. 

Commenter 0098 believes that the 30-day rolling compliance period does not 

properly account for the increased emissions at startup and shutdown. Specifically, the 

commenter believes that multiple startups and shutdowns within a 30-day operating period 

can drastically skew the data for any given period. As such, and consistent with EPA’s 

BACT determinations, the commenter urges the EPA to consider a 365-day rolling emission 

rate rather than the 30-day approach. According to the commenter, this allows the facilities to 
Page 37 of 80

more appropriately represent emissions over a longer time period, thereby accounting for 

SSM events as well as balancing seasonal impacts to emissions (i.e., higher summer 

emissions and lower winter emissions).

Commenter 0091 states that using long-term averaging periods for emission 

limitations is one way of addressing temporarily higher emission rates that even plants with 

the best demonstrated control technology may experience during startups and shutdowns, 

provided the EPA establishes the long-term emission rate using data that adequately 

represent emissions during startup and shutdown events. The commenter emphasizes that 

under CAA section 111, EPA must determine that emission limitations that are based on 

steady-state operation but will apply during startups and shutdowns are ”achievable” using 

emission reduction technology that the Administrator determines is the “best” and has been 

“adequately demonstrated.” According to the commenter, there is no indication in the 

preamble to the Proposed Rule that EPA has conducted a sufficient analysis to demonstrate 

the achievability of the proposed emission limit during startup and shutdown events. The 

commenter is skeptical that EPA has done so, because adequate emissions data for such an 

analysis often are not available for periods of startup and shutdown.

Commenter 0098 states that the EPA’s estimate of SSM events at three to four hours 

per month grossly underestimates such events. The commenter suggests that the EPA seek 

actual SSM event information from the industry in order to properly account for such events 

when setting the proposed NSPS. According to the commenter, SSM events are highly 

variable at NAPs, as some are scheduled and, of course, others are not. For one of the 

commenter’s organizational members, such events are scheduled for gauze changes 

(approximately every 140 days) during which the NAP can be down for nine hours. 

Moreover, the commenter believes that it is not unusual to have one or more additional SSM 

events between gauze changes. Another member typically experiences eight hour startups 

(with numerous startups per month), and has power loss (due to the grid) of three to four 

hours. Additionally, according to the commenter, older NAPs typically change out catalysts 

every 60 to 90 days, which can lead to additional SSM events each month. Thus, in the 

commenter’s experience, NAPs typically experience many more hours of SSM events during 

a 30-day period than the three to four hour average estimated by the EPA, which, in turn, 

bears directly on the achievability of the proposed NSPS, which is required continuously. 

Commenter 0092 states that even with selective catalytic reduction (SCR) emissions 

control equipment similar to dual pressure plants, mono-pressure nitric acid plants would 

have more difficulty meeting the proposed 30-day rolling emission rate because of start-up, 

shutdown and more frequent maintenance issues. According to the commenter, monopressure plants typically start up and shut down more frequently because the precious metal 

catalyst life cycle is shorter, typically about three months while dual pressure plants typically 

change catalyst every six to nine months. Therefore, according to the commenter, the 

proposed rolling emission rate of 30 days is too short. According to the commenter, more 

frequent thermal cycling of high temperature equipment also shortens the expected operating 

life of mono-pressure plants and increases the frequency of re-starts for maintenance issues. 

If both mono and dual pressure plants will be regulated under a single new NSPS standard,

the commenter asks that a longer rolling average time period be used.
Page 38 of 80

Commenter 0095 states that smaller plants that produce Nitric Acid for internal 

demand driven consumption incur very frequent startups and shutdowns and, therefore, have 

higher average NOX emissions. The assumption that the 30-day rolling emission rate that 

includes periods of startup and shutdown will compensate for the excess hourly emissions 

that occur during these periods with typically low emissions during steady state operations 

may be true for large commercial nitric acid producing plants, but according to the 

commenter, not the smaller ones. The commenter’s review of CEMS data that was submitted 

to the EPA under the 114 request indicates these emissions trends.

Commenter 0091 states there are several reasons why adequate data during SSM 

events often do not exist. According to the commenter, the applicable regulations generally 

prohibit testing during SSM conditions, and require that data not be used for compliance 

purposes if obtained during a startup, shutdown, or malfunction event. To the extent the EPA 

evaluates emissions data collected through continuous monitoring, the commenter notes that

the applicable regulations often require or allow the source to exclude from its reporting of 

continuous monitoring data those data reflecting SSM conditions. Also, according to the 

commenter, atypical pollutant concentrations and other stack conditions that may exist during 

startup and shutdown can result in the continuous monitoring system producing unusable 

data because the pollutant concentration may be outside of the monitoring equipment’s span 

or the stack conditions may not meet monitoring system QA/QC parameters, or the data may

be truncated on the high end because of limitations of the monitoring equipment. According 

to the commenter, these factors would cause the EPA to calculate an emission limit that 

understates emissions occurring during startup and shutdown. 

Additional concerns of commenter 0091 are: 

 If unusual stack conditions during a startup or shutdown event are outside the QA/QC 

parameters for a continuous monitor that is installed and calibrated to monitor normal 

operations, the commenter is concerned that the source may be in violation of the NSPS 

because of monitor unavailability; and

 The commenter suggests that the EPA clearly demarcate the conditions that should be 

characterized as either malfunctions or as startup or shutdown events.

 The commenter states that the EPA could better ensure that the standards applicable 

during startup and shutdown comply with the criteria for NSPS in CAA section 111. 

 The commenter recommends conducting stack testing during startup and shutdown 

events for certain types of sources and stack configurations, to better delineate the 

variations in emissions. (According to the commenter, stack sampling procedures may

not apply or may not produce accurate results during the abnormal flow and 

concentration conditions present during startup or shutdown.)

 The commenter recommends analyzing data from plants with continuous monitoring for 

startup and shutdown events at more facilities.

 The commenter recommends deferring promulgation of emission limitations that apply

during periods of startup or shutdown until after EPA obtains such data. 
Page 39 of 80

 The commenter recommends studying facilities’ operational logs to be sure it has chosen 

an averaging time for an emission standard sufficiently long that typical startups and 

shutdowns would not cause an exceedance of the standard.

 The commenter recommends determining, based on the infeasibility of collecting 

representative data during startup and shutdown events, that it is necessary and 

appropriate to promulgate a design, equipment, work practice, or operational standard, 

pursuant to CAA section 111(h) and/or section 302(k), in lieu of deriving limitations on 

the mass or concentration of pollutants emitted during startup or shutdown.

While the EPA calculated the proposed emission limits for nitric acid plants using 

continuous monitoring data that the Agency asserts included startup and shutdown events, it 

is not apparent to commenter 0091 whether or how that analysis adjusted for the limitations 

in monitoring data for periods of startup and shutdown described above, or that the data are 

representative of the magnitude of emissions during startup and shutdown. The commenter 

suggests that the EPA would need to analyze monitoring data for an extended period of time 

and for numerous facilities to try to establish emission limitations that could be met during 

startup and shutdown (with the level of control technology provided in CAA section 111). 

Expressing an emission limitation as a long-term average, while helping to address higher 

emissions during startup and shutdown, the commenter argues that the average could fail to 

account adequately for the potential wide variation in emissions during startup and shutdown 

events, which could be masked if the EPA simply assumes that calculating a long-termaverage emission rate from existing monitoring data will adequately address startups and 

shutdowns.

Commenter 0091 states that a particular problem with respect to characterizing 

emissions during startup and shutdown events for Nitric Acid plants is that the current NSPS 

for Nitric Acid plants only requires a continuous NOX monitor, which provides NOX

emissions in parts per million by volume (ppmv), but does not provide mass emissions (i.e., 

lb/hr), and yet the NSPS NOX standard is in terms of mass emissions (lb/ton of nitric acid 

produced). Under the existing (and proposed) NSPS, the commenter notes that a conversion 

factor is established during the initial performance tests to allow conversion of the ppmv 

values into lb/hr NOX emissions. According to the commenter, there does not appear to be 

any evidence, however, that these factors, which the EPA presumably used to set the 

proposed revised NSPS emission limit and are calculated based on normal steady-state 

operation, are applicable or valid for startup/shutdown events. (According to the commenter,

most existing nitric acid plants do not have stack gas flow rate monitors, since the current 

NSPS does not require one, and therefore, there is no actual data on lb/hr emissions during 

startup/shutdown events. Therefore, according to the commenter, the EPA likely has no valid 

lb/ton emission rate data during startup/shutdown events.)

Response to Comment 8.2: Commenters have argued that the emission limit is not 

achievable during malfunction events because testing is prohibited during SSM conditions. 

First of all, the commenter is referring to the RATA test, where the emission factor is 

determined for use with the NOX concentration CEMS to calculate emissions in units of the 

standard. This prohibition is not in place under normal operating procedures.
Page 40 of 80

Also commenters argued that data are not used for compliance purposes if obtained 

during a startup, shutdown, or malfunction. However, we note that the general provisions in 

Part 60 require facilities to keep records of the occurrence and duration of any startup, 

shutdown or malfunction (40 CFR 60.7(b)) and either report to the EPA any period of excess 

emissions that occurs during periods of startup, shutdown or malfunction (40 CFR 

60.7(c)(2)) or report that no excess emissions occurred (40 CFR 60.7(c)(4)). If the CEMS 

data do not represent these periods of startup, shutdown, and malfunction, it is unclear to the 

agency how nitric acid plants are complying with these requirements. Also see Section V of 

the final rule preamble for further discussion of the final standard.

Commenters noted that mono-pressure nitric acid plants would have more difficulty

meeting the proposed 30-day rolling emission rate because of start-up, shutdown, and more 

frequent maintenance issues. However, the EPA has obtained data from monopressure plants 

that showing compliance with the final standard of 0.50 lb NOX/ton acid has been 

demonstrated.

The requirements of Subpart G are such that the equipment used to measure the NOX

concentration has a span value of 500 parts per million (ppm). Commenters have indicated 

that the NOX concentrations during startup and shutdown can be higher than the monitor can 

measure. However, the one of the facilities upon which the standard was based uses a dualspan NOX monitor allowing us to determine the magnitude of emissions during periods when 

concentrations exceeded 500 ppm.

Additional data received included nitric acid plants that are not currently subject to 

subpart G and are generally not employing the best system of emissions reductions. As 

expected, these facilities may need to install additional controls to comply with subpart Ga if 

they are modified or reconstructed and trigger the standard. We have analyzed the cost of 

such controls and find them appropriate and cost effective. Also see the memo entitled 

Analyses of Data Received Between Proposal and Promulgation of Part 60, Subpart Ga in 

Docket ID No. EPA-HQ-OAR-2010-0750.

Commenters also noted that the vast majority of NAPs cannot avoid such increased 

emissions during startup and shutdown. The EPA notes that this standard does not apply to 

existing sources unless they are modified or reconstructed. This final emission limit of 0.50 

lb NOX/ton acid will only be applicable to new sources (which includes reconstructed or 

modified sources). We note that periods of startup and shutdown make up a very small 

fraction of total operating time. See Agrium North Bend Analyses for further analysis of 

startup and shutdown periods. We have shown that SCR is the best system of emission 

reductions currently in use because it achieves very low emissions, is cost effective, and 

produces minimal secondary environmental impacts.

NSPS does not prescribe a particular technological system that must be used to 

comply. Sources remain free to elect whatever combination of measures will achieve 

equivalent or greater control of emissions.

8c. Issues with SSM analysis
Page 41 of 80

Comment 8.3: Commenter 0098 suggests that as the EPA reevaluates its analysis 

regarding the impact of SSM on the achievability of a proposed NSPS that the EPA should 

provide technical definitions of the terms startup and shutdown that are specific to NAPs so 

that NAPs can determine when they are considered to be operating for purposes of 

compliance. Some of the commenter’s facilities are subject to differing definitions of these 

terms in consent decrees, create substantial disparity between how these terms are defined, 

which can have serious impacts as to how emissions are measured and evaluated.

For example, the commenter notes that in its analyses of the Test Plants, the EPA 

assumed that ammonia feed represented operating hours of the NAP, and that all other hours 

were not to be included in the 30-day rolling emission rate. Thus, the commenter notes that

its analysis of the PCS Geismar 5 data only included the hours where ammonia feed was 

greater than zero. According to the commenter, some NAPs define operation as when the 

NOX compressor is operational, while others consider the plant to be operating only when 

ammonia is flowing to the AOR. Also, the commenter notes the Consent Decree with Terra, 

where the EPA agreed that “startup begins one hour prior to the initiation of the feed of 

ammonia to the Covered Nitric Acid Plant and ends no more than five hours after such 

initiation of the feed of ammonia.” Additionally, the commenter notes that the Consent 

Decree states that “shutdown begins at the time the ammonia feed ceases and ends three 

hours later.” According to the commenter, these definitions are not consistent with the 

method the EPA used to calculate emissions at PCS Geismar 5, which is noted above.

Because there are differences in the industry regarding when startup and shutdown 

periods begin and end, and thus, when a NAP is considered operating, commenter 0098

recommends that the EPA define startup and shutdown such that NAPs are considered to be 

operational only when ammonia flow into the AOR is greater than zero. Thus, according to 

the commenter, startup would be defined as when ammonia is first introduced into the AOR, 

and shutdown as when ammonia flow to the AOR ceases. After defining startup and 

shutdown, the commenter requests that the EPA reevaluate the impact of such events on 

NAPs’ emissions, and their ability to achieve the proposed NSPS.

Commenter 0098 requests that the EPA revise the definition of an “operating day” for 

purposes of Subpart Ga. Frequently, according to the commenter, NAPs will begin startup or 

shutdown operations in the evening meaning that one or perhaps two days of the 30 

consecutive operating day period will be devoted to startups or shutdown emissions and these 

emissions may only last for a few hours. The result, according to the commenter, is that the 

emission rate, calculated as E30-day (§60.75a, Eq. 2), will be skewed with higher emissions 

relative to nitric acid production. In order to obtain more consistent data reporting periods,

the commenter asks that a minimum number of hours should be established to constitute an 

“operating day” to eliminate operating days consisting only of startup, shutdown or 

malfunction events. As an alternative approach, if the EPA continues to believe a 30-day

compliance period is appropriate, the commenter recommends that the EPA consider a 720 

hour compliance period, as opposed to a 30-day period.

Response to Comment 8.3: The EPA disagrees with the commenter’s statement that

the EPA’s analysis of PCS Geismar Train 5 was incorrect due to using data only where 

ammonia feed flow rate was greater than zero pounds per hour (lb/hr). The data received 
Page 42 of 80

from PCS Geismar stated that the train is operational when the ammonia feed flow rate is 

greater than 1 lb/hr. The EPA’s analysis contained a slight error because ammonia feed flow 

rates greater than 0 lb/hr were used to indicate whether the train was in operation. However, 

excluding emissions data that occurred while ammonia feed flow rates were between 0 and 1

lb/hr, the data analysis did not change significantly and the resulting conclusions did not 

change. Also, the EPA disagrees that a “NAP can be down for nine hours” is the same as the 

NAP undergoing nine hours of startup, shutdown, malfunction (SSM) events. When the NAP 

is down (in cold shutdown and not producing nitric acid), the process is not operating and 

there are no emissions. When the NAP is undergoing SSM events, there are emissions.

However, the EPA agrees that a correction should be made to the way that the NOX

emissions are calculated over the 30 day compliance period. The final rule calculation will be 

based on how many hours the unit operated over each 30 day period, up to 720 hours. Each 

hour is weighted equally whether this hour is a normal operating hour or an hour where 

startup, shutdown, or malfunction occurred during a 30 day period. 

Also, the EPA agrees that some facilities may undergo more (or fewer) periods of 

startup and shutdown during a typical 30 day period compared to the facilities for which we 

had emissions data. Nonetheless, we still believe these periods make up a very small fraction 

of total operating time. Further, the EPA has performed hypothetical calculations in which 

the number of SSM periods during a month was doubled, and the standard was still achieved. 

Additionally, the updated method for calculating the 30 day rolling emission rate should 

prevent these infrequent and short duration periods from having artificially inflated impacts 

on the 30 day rolling emission rate values. See the memo Agrium North Bend Analyses, and

the memo Statistical Evaluation of CEMS Data to Determine the NOX Emission Standard 

(Updated Memo for Final Standard). Also see Section V of the final rule preamble for more 

discussion of the final standard.

Also, the EPA agrees with the commenter’s statement about monitor unavailability. 

In order to lessen the likelihood that a monitor installed and calibrated to monitor normal 

operations will not be able to be used to monitor emissions during SSM events, the EPA has 

added a requirement to use dual span monitors. This ensures that the monitor has been 

calibrated for the ranges of emissions expected during normal operations and during SSM 

events.

The EPA disagrees with the commenters that definitions for startup and shutdown are 

needed. Due to the fact that the emission standard for nitric acid plants must be met at all 

times, including startup and shutdown, there is no need to define startup and shutdown 

specifically for nitric acid plants. Therefore, the definitions contained in the General 

Provisions for Part 60 are appropriate. 

8d. Numerical emission limit should apply during SSM

Comment 8.4: Commenter 0104 states that the EPA’s proposed 30-day averaging 

period may be adequate if periods of startup and shutdown are included and malfunctions are 

not excused. As a general principle, the commenter states that averaging times should not be 

stretched simply to accommodate whatever emissions may result from these events. Rather, 
Page 43 of 80

the commenter urges the EPA to evaluate their causes and determine whether specific 

requirements should be included within the NSPS performance standards for each industry to 

reduce the frequency and severity of such episodes. For example, when determining the 

NSPS performance standard, the commenter recommends that the EPA consider the impact 

of downtime and accident history on emission levels from the different pollution control 

options it is evaluating before making its selection.

The commenter recognizes that starting up and shutting down units for repair in 

response to market conditions is an inevitable feature of plant operation. So long as the 

EPA’s 30-day rolling emission rate is based on actual hours of operation, the commenter 

notes that it may be reasonable in light of the limited information available in the docket. 

It is difficult to respond to the EPA’s invitation to comment on whether the 

compliance period should be shorter, as the commenter notes that the information in the 

docket does not always distinguish between emissions resulting from malfunctions and those 

that are driven by startup and shutdown. Regardless of that distinction, the commenter 

believes that the data does indicate that, at the very least, the 30-day compliance period

should be more than adequate to accommodate startups and shutdowns, and that a shorter 

compliance period may not have a significant impact on emissions. 

According to the commenter, the EPA has recognized that there is no basis in law for 

excusing malfunctions, either directly or by manipulating averaging times in anticipation that 

pollution control equipment will fail. Such a loophole would, in the opinion of the 

commenter, reward those companies that choose not to invest in maintenance or otherwise 

operate their facilities in a negligent manner. According to the commenter, the CEMS data 

available indicate that malfunctions are relatively infrequent and should have no impact on 

compliance with the 30-day limit that EPA has proposed. In addition, the commenter notes 

that EPA is basing its standard on emission levels that plants built long ago are already 

achieving 99% of the time; newer units should be expected to achieve higher performance 

levels.

Response to Comment 8.4: The EPA agrees with the commenter that the NOX

emission standard should apply during startup, shutdown, and malfunction. 

There is nothing in CAA section 111 that directs the Agency to consider malfunctions 

in determining the level “demonstrated” by the application of the “best system of emission 

reduction” when setting emission standards. Moreover, while the EPA accounts for 

variability in setting emissions standards consistent with the CAA section 111 case law, 

nothing in that case law requires the Agency to consider malfunctions as part of that analysis. 

Clean Air Act section 111 uses the concept of “best system of emission reduction” in

defining the level of stringency that CAA section 111 performance standards must meet. 

Applying the concept of “best system of emission reduction” to a unit that is malfunctioning 

presents significant difficulties, as malfunctions are sudden and unexpected events.

As explained above, the EPA has determined that CAA section 111 does not require 

that emissions that occur during periods of malfunction be factored into development of 

CAA section 111 standards.
Page 44 of 80

8e. Impact of DC Circuit Court’s Sierra Club decision

Comment 8.5: Commenters (0091, 0098) state that the EPA failed to properly

consider the impact of SSM events when setting the proposed NSPS.

Commenters (0091, 0098) state that the EPA conducted no analysis of what impact 

malfunctions have on the achievability of its proposed NSPS, other than to state that 

malfunction events were covered by the data it analyzed with respect to the Test Plants. The 

commenters note that the reasoning is in error for the same reason the EPA’s reasoning 

regarding startup and shutdown events is in error.

The commenters state that the EPA did not address what impact the D.C. Circuit 

Court’s Sierra Club decision has under CAA §111 in this rulemaking. Instead, without 

comment or explanation, the commenters state that the EPA proceeded to draft a proposed 

NSPS that requires continuous compliance, including during SSM events, a departure from 

over 40 years of contrary requirements. Such an action, alone, according to the commenters, 

is arbitrary and capricious. The commenters assert that the EPA made no attempt to analyze 

what impact SSM events have on the achievability of the proposed NSPS. Commenter 0098 

objects to the proposed accounting of startup and shutdown periods by using a 30-day

compliance period. The commenters state that the EPA provides no analysis or data to 

support this claim, but instead apparently believes that a 30-day compliance period is 

sufficient based on the emissions data from the Test Plants. The commenter states that the 

30-day compliance period is too short.

Response to Comment 8.5: The EPA does not claim that the Sierra Club case 

constrains its authority to prescribe unique standards for SSM periods or directly addresses 

the legality of SSM exemptions for section 111 standards. The EPA’s view is that the 

reasoning of the Sierra Club decision calls into question the legality of source categoryspecific SSM exemptions in rules promulgated pursuant to section 111. The EPA also 

disagrees with the commenter that contends that the Sierra Club decision addresses in any

way the EPA‘s current approach to malfunctions.

Periods of startup, normal operations, and shutdown are all predictable and routine 

aspects of a source’s operations. However, by contrast, malfunction is defined as a “sudden, 

infrequent, and not reasonably preventable failure of air pollution control equipment, process 

equipment, or a process to operate in a normal or usual manner * * *”(40 CFR 60.2). 

Nothing in CAA section 111 directs the Agency to consider malfunctions in

determining the level “demonstrated” by the application of the “best system of emission 

reduction” when setting emission standards. Moreover, while the EPA accounts for 

variability in setting emissions standards consistent with the CAA section 111 case law, 

nothing in that case law requires the Agency to consider malfunctions as part of that analysis. 

Clean Air Act section 111 uses the concept of “best system of emission reduction” in

defining the level of stringency that CAA section 111 performance standards must meet. 

Applying the concept of “best system of emission reduction” to a unit that is malfunctioning 

presents significant difficulties, as malfunctions are sudden and unexpected events.
Page 45 of 80

As explained above, the EPA has determined that CAA section 111 does not require 

that emissions that occur during periods of malfunction be factored into development of 

CAA section 111 standards. Also refer to Section V of the final rule preamble.

8f. Safety issues during SSM

Comment 8.6: Commenter (0098) states that the EPA failed to consider safety 

issues associated with its proposal, as required by CAA §111(a)(1). According to the 

commenter, the EPA must account for these safety concerns when it attempts to bring 

startups and shutdowns within its NOX standard.

According to the commenter, there are two major safety issues surrounding startup 

and shutdown procedures that require very low levels of NOX emissions. The commenter 

notes the first issue is the creation and accumulation of ammonia nitrite in the absorption 

tower. If a NAP is started slowly and the primary gauze is not heated to its appropriate levels 

immediately, the commenter notes that there is a risk of ammonia “slip” from the AOR 

down-stream into the process stream. Under conditions present in the stack, the commenter 

states that the ammonia and NOX that have slipped into the flue gas can react, forming 

ammonium nitrite, an unstable ammonia salt which is explosive at temperatures greater than 

60-70°C (140-158°F). Depending on conditions, the commenter notes that the ammonia 

nitrite can also be formed and deposited, which also creates a risk of explosion.

According to the commenter, the second safety concern involves the accumulation of 

ammonia within the SCR unit itself. In order to ensure that all NOX has been destroyed, the 

commenter notes that the SCR unit can be run without the plant being operational. Without 

appropriate levels of NOX being supplied to the SCR by means of the AOR and/or the 

compressor, the commenter states that ammonia will accumulate within the SCR unit, which

can lead to the disintegration of the SCR catalyst and can create an explosive environment 

within the SCR shell, which is especially dangerous considering the high levels of heat 

involved in the process.

Response to Comment 8.6: We recognize that safety hazards can occur if certain 

conditions are present in the control device. However, there are methods to prevent these 

conditions, such as hydrogen peroxide injection (HPI) or startup heaters that are in use in the 

industry. For small plants, startup heaters can be purchased and installed for approximately

$400,000.

If the above methods cannot be used, the facility needs to exercise caution when 

starting up control equipment to ensure that these conditions do not occur. However, the 

emission standard is based on a sufficiently long compliance period that if higher emissions 

occur during startup and shutdown because control devices cannot be operated in the same 

manner in which they’re used during steady state operations, the impact of those emissions 

should be sufficiently small that they will not create significant compliance problems.

8g. Affirmative defense is unnecessary

Comment 8.7: Commenter 0095 states that the affirmative defense is unnecessary

and commenters 0098 and 0104 ask that the EPA eliminate the affirmative defense.
Page 46 of 80

Commenter 0098 notes that nothing in CAA §111 expressly commands EPA to 

account for malfunctions and the EPA cannot ignore such events when setting an NSPS. 

According to the commenter, it is the EPA’s duty to ensure that an NSPS is set at an 

achievable level, and that its analysis necessarily includes considering events that impact 

emissions at NAPs. The commenter asserts that the EPA has failed to meet that duty when 

setting the proposed NSPS. Moreover, the commenter notes that EPA’s proposal to soften its 

failure to account for malfunctions by suggesting it will exercise appropriate enforcement 

discretion or by creating an affirmative defense does not suffice. According to the 

commenter, substituting enforcement (whether based on an affirmative defense or the 

exercise of enforcement discretion) for actual emission limitations was long-ago rejected by 

the D.C. Circuit and is not an option. [The commenter references Portland Cement, 486 F.2d 

at 399; and also Nat’l Lime, 627 F.2d at 431 n.46 (enforcement does not render an NSPS 

standard achievable), 434 n. 54 (suggesting that in evaluating achievability and 

representativeness, the CAA 1977 amendments’ requirement that sources meet emissions 

limitation continuously may have repealed any flexibility EPA had to exclude consideration 

of SSM events when setting NSPS).]

Commenter 0104 states that the EPA’s proposed “affirmative defense” to civil 

penalties based on malfunction events is unlawful, would likely reduce compliance with the 

proposed standards, and would have harmful consequences for public health and the 

environment.

According to commenter 0104, the statute makes clear that only courts and judges are 

authorized to assess civil penalties, whether a case is brought by the EPA or a citizen. 

Moreover, in the opinion of the commenter, Congress expressed a clear intent as to how 

judges should determine the size of civil penalties whenever they are sought, and thus 

Congress flatly barred the EPA from limiting when civil penalties can be assessed. Indeed,

according to the commenter, the Clean Air Act itself spells out the only limits that Congress 

intended to impose on citizens’ ability to seek and recover penalties in enforcement suits. By

attempting to impose additional agency-created limits, the commenter believes that the EPA 

exceeds its authority.

Commenter 0104 notes as an example--in an enforcement action against a nitric acid 

plant for a violation of the NSPS performance standards, the owner might argue that it is 

exempt from paying civil penalties so long as the owner satisfied the requirements set forth 

in the EPA’s proposed affirmative defense regulations. According to the commenter, the 

owner of a facility must not be able to evade the civil penalties that apply when the 

congressionally mandated factors in the statute are met. The commenter states:

See 42 U.S.C. § 7413(e) (listing factors). Note that the proposed 

exemption would also be barred under Chevron step two or found to be 

arbitrary and capricious since, even if there exists some slight ambiguity, 

it is unreasonable to construe the statute as permitting EPA to shortcircuit the consideration of specifically listed factors. See Chevron, 467 

U.S. at 843 (explaining that, if the statute does not answer the question at 

issue, “the question for the court is whether the agency’s answer is based 

on a permissible construction of the statute”); S. Coast Air Quality Mgmt. 
Page 47 of 80

Dist. v.EPA, 472 F.3d 882, 895 (D.C. Cir. 2006) (“We further hold that 

EPA’s interpretation of the Act in a manner to maximize its own 

discretion is unreasonable because the clear intent of Congress in 

enacting the 1990 Amendments was to the contrary.”); see also Gen. 

Instrument Corp. v. F.C.C., 213 F.3d 724, 732 (D.C. Cir. 2000) 

(explaining that “an arbitrary and capricious claim and a Chevron step 

two argument overlap”); Motor Vehicle Mfrs. Ass’n of U.S., Inc. v. State 

Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43 (1983) (explaining that an 

agency acts in arbitrary and capricious manner if it fails to consider 

“relevant factors” or “entirely fail[s] to consider an important aspect of 

the problem”). By “upset[ting] the statutory balance struck by Congress,” 

as discussed above, the affirmative defense is unreasonable under 

Chevron step two. Int’l Alliance of Theatrical & Stage Employees v. 

N.L.R.B, 334 F.3d 27, 35 (D.C. Cir. 2003).

The commenter continues by saying 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 Section 304(a), and the EPA should not ask a court to ignore its legal duty. According 

to the commenter, it is simply impermissible for the EPA to displace the civil penalty factors 

of the Clean Air Act or alter their significance by creating a bar to penalties if certain agencydefined considerations are met instead. The commenter states:

In another proceeding, EPA has argued that it may promulgate an 

affirmative defense as an interpretation of the ‘catchall’ provision of 

Section 113(e)(1), which directs “the Administrator or the court, as 

appropriate,” to consider the enumerated factors and “such other factors 

as justice may require.” Partial Approval of Texas SIP, 75 FR 68989, 

68999 (Nov. 10, 2010). As noted above, however, with respect to civil 

penalties, this provision represents a Congressional delegation of 

discretion to judges, not EPA. Moreover, even if EPA had authority to 

interpret “other factors,” EPA’s proposed affirmative defense would 

require a court to elevate these additional factors above and in 

contradiction to those enumerated by the statute, and this is not a 

reasonable or permissible interpretation.

According to Commenter 0104, the Clean Air Act grants EPA minimal discretion that 

only applies to administrative penalties, allowing the EPA to “compromise, modify, or remit, 

with or without conditions, any administrative penalty which may be imposed under 

[subsection 113(d)].” According to the commenter, there is no similar grant of authority, 

however, for the EPA to compromise, modify, or limit civil penalties that a court may impose 

under Section 113(e) or Section 304. According to the commenter, Section 304(a) grants 

courts the sole authority “to apply any appropriate civil penalties” in citizen suits. The 

explicit reference to the EPA’s ability to modify penalties in one subsection and its absence 

in the other subsection of the same provision, according to the commenter, can only be 

understood as an intentional delineation of EPA authority by Congress that EPA may not 

contravene by rule.
Page 48 of 80

Commenter 0104 urges the EPA not to adopt in its final rule any affirmative defense 

because a regulatory limitation on civil penalties intrudes upon the authority Congress 

granted solely to courts to impose civil penalties for violations of the Clean Air Act.

Commenter 0104 states that Congress plainly intended for citizens to be able to 

enforce emission standards under the Clean Air Act using the full range of civil enforcement 

mechanisms, subject only to the limitation that government not be “diligently prosecuting” 

its own civil enforcement action. Under the proposed rule, according to the commenter, 

citizen participation in Clean Air Act enforcement will be hindered, in violation of citizens’ 

rights to protect themselves from pollution and in direct conflict with congressional intent. 

The affirmative defense proposed here by the EPA would, according to the commenter,

likely be used on a routine basis by polluters seeking to avoid penalties, just as the 

malfunction exemption was. As a result, the commenter believes that citizens who seek the 

assessment of civil penalties against polluters in order to protect themselves and achieve the 

Act’s goals may be forced to engage in fact-intensive disputes over the cause of emission 

violations and the adequacy of responsive measures—an outcome Congress intended to 

prevent with the simple straightforward enforcement and penalty provisions in the Clean Air 

Act. As a result, the commenter states that compliance with the Act could suffer, for civil 

penalties provide a powerful deterrent to violators as Congress intended. According to the 

commenter, the Supreme Court has explained: “To the extent that [civil penalties] encourage 

defendants to discontinue current violations and deter them from committing future ones, 

they afford redress to citizen plaintiffs who are injured or threatened with injury as a 

consequence of ongoing unlawful conduct.”

Commenter 0104 continues: Thus, the affirmative defense runs counter to the clearly

expressed intentions of Congress because the burden it places on citizens makes it less likely

that they will enforce the Act, and several of the factors at issue in the affirmative defense 

undercut Congress’s intent that citizen suit enforcement should avoid re-delving into 

“technological or other considerations.” According to the commenter, both result from the 

technical burden the EPA is proposing to place on citizens with the affirmative defense, and 

both render the affirmative defense impermissible.

Commenter 0104 states that Congressional intent on civil penalties is clear—they are 

a remedy available for enforcement by citizen plaintiffs, and the Act gives judges a list of 

factors to consider in assessing them. The commenter asserts that the EPA cannot write 

regulations contravening that intent. By shifting this careful balance and contravening these 

mandates, the EPA’s proposed affirmative defense for nitric acid plants will, according to the 

commenter, impermissibly chill citizen participation and hinder their ability to win an 

effective, deterrent remedy in Clean Air Act enforcement actions.

According to the commenter, much like citizens, neither the EPA nor state agencies 

have the resources to investigate, much less contest, affirmative defenses. The commenter 

asserts that promulgating this affirmative defense is equivalent to giving polluters “get out of 

jail free” cards for serious violations. According to the commenters, polluters are likely to 

claim that any violation of the standard is due to a malfunction in order to evade the 

applicable requirements and the consequences of violating them. the commenter claims that 

allowing polluters to evade financial penalties—which are the real teeth of the standards—
Page 49 of 80

through this type of measure is likely to lead to polluters simply ignoring or factoring 

potential standard violations into their cost of doing business, rather than actually trying to 

prevent malfunctions and violations of the standards as a way to avoid financial losses from 

the application of penalties.

Commenter 0099 disagrees with the EPA’s proposal to “add an affirmative defense to 

civil penalties for exceedances of emission limits that are caused by malfunctions,” and urges 

the EPA to withdraw its proposed creation of an affirmative defense in its entirety.

The commenter states that creation of such a new loophole is illegal and unwarranted, 

and the proposal does not support the agency’s duty to protect public health. The commenter 

notes that the Clean Air Act specifies how the courts are to assess civil penalties, whether a 

case is brought by the EPA or a citizen. According to the commenter, Congress plainly

intended citizens to be able to enforce emission standards under the CAA using the full range 

of civil enforcement mechanisms available to the government. The commenter states that the 

EPA’s proposal, by purporting to shift this balance and contravening these mandates, violates 

the statute and impairs the ability of affected communities to enforce their right to protection 

from harmful pollution.

Moreover, commenter 0099 believes that the EPA’s proposed standard already

accounts for periods of malfunction: the EPA believes “that sources will be able to operate 

their plants in compliance with the standard even if they experience malfunctions.” The 

commenter believes the proposed standard is insufficiently stringent even for NOX, and it 

makes no sense to add an additional loophole on top of a standard that already accounts for 

the purported inevitability of malfunction at nitric acid plants.

Commenter 0095 states that the affirmative defense provisions are not necessary for 

a NSPS rule since the Part 60 Rules were not impacted by the D. C. Circuit’s decision in 

Sierra Club vs. EPA, which vacated the exemption for excess emissions during SSM events 

contained in 40 CFR Part 63, subpart A. In fact, according to the commenter, the NSPS rule 

structure does not require sources to meet NSPS emission limitations during SSM events in 

40 CFR Section 60.8(c). The commenter quotes:

“Operations during periods of startup, shutdown, and malfunction shall not constitute 

representative conditions for the purpose of a performance test nor shall emissions in excess of 

the level of the applicable emission limit during periods of startup, shutdown, and malfunction be 

considered a violation of the applicable emission limit unless otherwise specified in the 

applicable standard.”

Response to Comment 8.7: The EPA included an affirmative defense in the final 

rule in an attempt to balance a tension, inherent in many types of air regulation, to ensure 

adequate compliance while simultaneously recognizing that despite the most diligent of 

efforts, emission standards may be violated under circumstances beyond the control of the 

source. The EPA must establish emission standards that “limit the quantity, rate, or 

concentration of emissions of air pollutants on a continuous basis.” 42 U.S.C. § 

7602(k)(defining “emission limitation and emission standard”). See generally Sierra Club v. 

EPA, 551 F.3d 1019, 1021 (D.C. Cir. 2008). Thus, the EPA is required to ensure that section 

111 emissions standards are continuous. The affirmative defense for malfunction events 
Page 50 of 80

meets this requirement by ensuring that even where there is a malfunction, the emission 

limitation is still enforceable through injunctive relief. 

While “continuous” limitations, on the one hand, are required, there is also caselaw 

indicating 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 ‘never to be exceeded’ standard currently in 

force.” See also, Portland Cement Association v. Ruckelshaus, 486 F.2d 375 (D.C.Cir. 1973). 

Though intervening caselaw such as Sierra Club v. EPA and the CAA 1977 amendments 

calls into question the relevance of these cases today, they support the EPA’s view that a 

system that incorporates some level of flexibility is reasonable. The affirmative defense 

simply provides for a defense to civil penalties for 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 holder.” Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977). 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” as 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 district courts 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 determined 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, 

then a penalty is not appropriate and penalty assessment pursuant to the section 113(e)(1) 

factors does not occur.

Additionally, the affirmative defense is reasonable. The EPA’s judgment is that the 

affirmative defense criteria capture the appropriate considerations in determining whether 

penalties are appropriate when a violation occurs as the result of a malfunction. As noted 

above, the affirmative defense criteria overlap to some extent with the penalty assessment 

criteria set forth in section 113(e), but are not identical. For example, size of business is one 

of the factors listed in section 113(e), but is not reflected in the EPA’s affirmative defense. 

This reflects the EPA’s view that when a violation is caused by a malfunction, the size of the 

business is not relevant to whether penalties should be excused. If the violation was 

unavoidable and could not have been prevented, the EPA’s view is that it would be unfair to 

impose a penalty no matter the size of the business. 
Page 51 of 80

In further response to the commenter that stated the affirmative defense provisions are 

not necessary for NSPS standards, the reference to 40 CFR Section 60.8(c) affirms the EPA’s 

position on SSM for Section 111 sources. The paragraph can be interpreted to allow 

“emissions in excess of the level of the applicable emission limit during periods of startup, 

shutdown, and malfunction [to] be considered a violation of the applicable emission limit” if

“specified in the applicable standard.” 

It follows that the language “unless otherwise specified in the applicable standard” 

means that the EPA has the right to override the provisions of 40 FR Section 60.8(c) simply

by stating it in the applicable subpart, which the EPA has done by finalizing Subpart Ga of 

Part 60.

8h. Affirmative defense-shifting the burden of proof

Comment 8.8: Commenter 0091 questions the EPA’s legal authority in the CAA to 

shift the burden to the regulated community of proving (or disproving) essential elements of 

an alleged violation. The commenter believes that the statute is silent as to the issue and “the 

ordinary default rule [is] that plaintiffs bear the risk of failing to prove their claims.” Shaeffer 

v. Weast, 546 U.S. 49 (2005), quoting McCormick on Evidence §337, at 412.

(“The burdens of pleading and proof with regard to most facts have and 

should be assigned to the plaintiff who generally seeks to change the present 

state of affairs and who therefore naturally should be expected to bear the risk 

of failure or proof or persuasion”); C. Mueller & L. Kirkpatrick, Evidence § 

3.1, p. 104 (3d ed. 2003) (“Perhaps the broadest and most accepted idea is that 

the person who seeks court action should justify the request, which means that 

the plaintiffs bear the burdens on the elements in their claims”). 

The commenter notes that while the Supreme Court has recognized exceptions such 

as affirmative defenses, the commenter asserts that courts retain the authority to establish 

such rules unless Congress acts to delegate that authority. In this instance, according to the 

commenter, the EPA has not provided any statutory authority, nor any real justification, for 

requiring a source to prove its innocence; moreover, to fully demonstrate its innocence within 

30 days of the event, without even being charged. The commenter states that if the EPA 

adopts an approach along the lines of the proposed affirmative defense, it should be stated 

instead in terms that, once a source has claimed that its excess emissions were related to a 

malfunction, it will not be considered to be in violation of the standards unless the 

enforcement authority demonstrates that the source is not entitled to claim the malfunction.

Response to Comment 8.8: The EPA 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 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 C.F.R. 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 
Page 52 of 80

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).

8i. Affirmative defense—injunctive relief

Comment 8.9: Commenter 0091 notes that The Proposed Rule states that: “The 

affirmative defense shall not be available for claims for injunctive relief.” According to the 

commenter, the preamble to the Proposed Rule does not give any explanation for why the 

affirmative defense would not apply to injunctive relief. If in fact the excess emissions 

associated with the equipment or process failure are not reasonably preventable, the 

commenter asserts that there is no apparent reason why injunctive relief should be available 

either. According to the commenter, as a matter of law, injunctive relief may not be available 

in cases where a civil penalty cannot be imposed. See Sierra Club v. Otter Tail Power Co., 

615 F.3d 1008 (8th Cir. 2010) (under concurrent remedy doctrine, injunctive relief for a 

CAA violation is barred when civil penalty is barred by statute of limitations).

The commenter states that maintaining liability for injunctive relief renders the 

affirmative defense particularly ineffective with respect to citizen suits. According to the 

commenter, if the source is even potentially subject to injunctive relief, and therefore could 

be required to pay the citizen-plaintiff’s attorneys fees even if the source successfully 

demonstrated that it otherwise qualified for the affirmative defense, then the affirmative 

defense would not accomplish EPA’s stated objective of providing relief in situations where 

the emission limitations cannot be met despite proper design and operation of process and 

control equipment.

The commenter notes that the EPA has not addressed these and other apparent 

limitations and shortcomings of the affirmative defense, which make it an entirely inadequate 

substitute for setting NSPS that include provisions for SSM events. Moreover, according to 

the commenter, the EPA has provided no analysis that would supersede its long-standing 

determination that it is not desirable to rely on enforcement, rather than regulatory language, 

to address the inability to comply with technology-based standards during SSM events. See 

37 Fed. Reg. 17,214, 17,214 (Aug. 25, 1972) (establishing SSM provision in NSPS). The 

commenter states that courts have adopted the same view. See National Lime, 627 F.2d at 

431 n.46 (“the flexibility appropriate to enforcement will not render ‘achievable’ a [NSPS] 

which cannot be achieved on a regular basis, either for the reasons expressly take into 

account in compliance determination regulations (here startup, shutdown and malfunction), 

or otherwise.). See also Marathon Oil Co. v. EPA, 564 F.2d at 1273 (explaining why EPA’s 

proffered assurances that it would not take enforcement action against sources that exceeded 

effluent limitations because of upset events was “not an adequate response” to the argument 

that standards that cannot be met during unavoidable upsets fail to reflect available 

technology).

At a minimum, the commenter asks that the EPA state that the affirmative defense 

applies to civil penalties, civil administrative penalties, noncompliance penalties, and 
Page 53 of 80

injunctive relief, in an action brought by the EPA, a state, or a citizen-suit plaintiff. The 

commenter also asks that the EPA reword the “affirmative defense,” so that it states that a 

source “will not be deemed in violation of” the NSPS for excess emissions or other 

deviations from the standards, associated with a startup, shutdown, or malfunction event, 

unless the event, and the source’s response to the event, do not meet the criteria spelled out in 

the regulations. Configured in that way, the commenter believes that this provision should be 

called something other than an “affirmative defense,” such as an “alternative standard for 

SSM events.”

Response to Comment 8.9: In exercising its authority under section 111 to establish 

emission standards (at a level that meets the stringency requirements of section 111), the 

EPA necessarily defines conduct that constitutes a violation. The EPA’s view is that the 

affirmative defense is part of the emission standard and defines two categories of violation. If 

there is a violation of the emission standard and the source demonstrates that all the elements 

of the affirmative defense are met, only injunctive relief is available. All other violations of 

the emission standard are subject to injunctive relief and penalties.

8j. Errors and Inconsistencies in Affirmative Defense language

Comment 8.10: Commenter 0098 notes errors and inconsistencies in the affirmative 

defense language.

Commenter 0098 states that the definition of a “malfunction” in the proposed 

affirmative defense provision is broader than that set forth in EPA’s NSPS definition of a 

“malfunction.” In proposed §60.74a(a)(1)(i), the commenter notes that a malfunction 

includes “excess emissions” that “[w]ere caused by a sudden, infrequent, and unavoidable 

failure of air pollution control and monitoring equipment, process equipment, or a process to 

operate in a normal or usual manner.” (emphasis added). By comparison, the commenter 

notes that the definition of a malfunction set forth in the §60.2 definition is “a sudden, 

infrequent, and not reasonably preventable failure of air pollution control equipment, process 

equipment, or a process to operate in a normal or usual manner.” (emphasis added). 

According to the commenter “unavoidable” in proposed § 60.74a(a)(1)(i) sets a much higher 

bar than “not reasonably preventable” in §60.2. If EPA wants to change the definition of a 

malfunction for purposes of the NSPS program, or impose a more stringent definition on a 

particular source category, the commenter demands that EPA explain its departure from the 

long-standing agency position.

Commenter 0098 states that the affirmative defense also contains several references 

to “excess emissions.” According to the commenter, this term is neither defined in the 

general NSPS provisions nor in proposed Subpart Ga. The commenter asks that the EPA 

propose a definition of “excess emissions” before moving forward with the affirmative 

defense.

Response to Comment 8.10: Subpart Ga has not been changed to include a 

definition for “excess emissions.” Changes were made to the affirmative defense language to 

refer to “violations” rather than “excess emissions.” 
Page 54 of 80

The EPA disagrees that the criteria of the affirmative defense changes the definition 

of malfunction (as defined in 40 CFR 60.2) for purposes of the NSPS program. With respect 

to the wording difference between the §60.2 definition of “malfunction” and the criterion 

stated in §60.74a(a)(1)(i), the EPA does not intend that the affirmative defense will be 

available in every instance of a malfunction.

8k. Revisions to Affirmative Defense Language

Comment 8.11: Multiple commenters offered suggestions for changing the 

affirmative defense language.

Commenter 0095 suggests the following revisions to §60.74(a):

(a) (2) Repairs were made as expeditiously as practical possible when the 

applicable emission limitations were being exceeded. Off shift and overtime 

labor were used, to the extent practical to make these repairs; and

The commenter notes that responding to malfunctions many times is a case-by-case 

situation depending on the specifics of the malfunction and equipment to be repaired, and the 

language regarding off-shift and overtime labor is unnecessary and confusing. According to 

the commenter, the use of overtime or off-shift labor is only one consideration in how to 

address a malfunction event. If the EPA wants to emphasize that the use of overtime or offshift labor must be used, the commenter recommends this language be included in the 

preamble rather than the rule itself.

(a) (7) All of the actions in response to the excess emissions were documented 

by properly signed, contemporaneous operating logs; and

The commenter notes that electronic media to document actions in response to excess 

emissions is used in the commenter’s plant that will be subject to this rule. The commenter 

notes that imposing a requirement to print and sign a record of such action is outdated if one 

can document the response to actions in an electronic format.

Commenter 0095 recommends that if the EPA chooses to retain the affirmative 

defense provisions in the regulation:

 For malfunctions that result in only small levels of excess NOX emissions, instead of 

requiring the regulated entity to establish and prove an affirmative defense, the 

commenter asks that the EPA establish a work practice requirement that requires the 

owner/operator to stop the emissions, stop the malfunction, and to return to normal 

operations as soon as practical.

 In Section 60.74a, the EPA proposes that nine requirements be met in order for a facility 

to claim an affirmative defense for a malfunction; according to the commenter, some of 

these requirements are unreasonable, difficult to demonstrate, and subject to varying 

interpretation.

Commenter 0100 suggests the following modifications to the language to make it 

more usable: Requirements in § 60.74a are impossible to meet due to the use of ambiguous 
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terms such as “careful,” “proper,” or “better.” Until these are defined, the commenter thinks

it is impossible to determine whether these criteria have been met. The commenter suggests 

the following modifications to the language to make it more usable if the EPA keeps the 

affirmative defense concept: 

 The commenter asks that the EPA drop the reference to “any” activity in § 60.74a.

According to the commenter, there are also several references to “All” that would make it 

difficult to ever satisfy the requirements of an affirmative defense.

 According to the commenter, the language in the provision is contradictory; in paragraph 

(a), the phrase “preponderance of evidence” is used while later in that paragraph (iii), the 

language refers to “any activity.”; this same trend occurs in paragraphs (5) – “All 

possible,” (6) “All,” (7) “All of the actions,” and (8) “At all times.” According to the 

commenter, “all” would include “preponderance,” but “preponderance” does not mean all 

of the time. The commenter suggests that the phrase “preponderance of evidence” is 

adequate and the references to “all” and “any” in the later paragraphs should be modified.

The commenter suggests that the EPA consider making the following modifications 

(using strikeout to show text deleted and underline to show text added) to the regulatory

language in § 60.74a to address the concerns mentioned above and to make an affirmative 

defense a more useful tool.

§ 60.74a Affirmative Defense for Exceedance of Emission Limit During 

Malfunction.

In response to an action to enforce the standards set forth in paragraph § 60.72a, you 

may assert an affirmative defense to a claim for civil penalties for exceedances of 

such standards that are caused by malfunction, as defined at 40 CFR 60.2. 

Appropriate penalties may be assessed, however, if you fail to meet your burden of 

proving all of the requirements in the affirmative defense. The affirmative defense 

shall not be available for claims for injunctive relief.

(a) To establish the affirmative defense in any action to enforce such a limit, you must 

timely meet the notification requirements in paragraph (b) of this section, and must 

prove by a preponderance of evidence that:

(1) The excess emissions:

(i) Were caused by a sudden, infrequent, and unavoidable failure of air pollution 

control and monitoring equipment, process equipment, or a process to operate in a 

normal or usual manner, and

(ii) Could not have been reasonably prevented through careful planning, proper 

design or better operation and maintenance practices; and

(iii) Did not stem from any activity or event that could have been reasonably foreseen 

and avoided, or planned for; and
Page 56 of 80

(iv) Were not part of a recurring pattern indicative of inadequate design, operation, or 

maintenance; and

(2) Repairs were made as expeditiously as possible when the applicable emission 

limitations were being exceeded. Off-shift and overtime labor were used, to the extent 

practicable to make these repairs; and

(3) The frequency, amount and duration of the excess emissions (including any

bypass) were minimized to the maximum extent practicable during periods of such 

emissions; and

(4) If the excess emissions resulted from a bypass of control equipment or a process, 

then the bypass was unavoidable to prevent loss of life, personal injury, or severe 

property damage; and

(5) All possible Reasonable steps were taken to minimize the impact of the excess 

emissions on ambient air quality, the environment and human health; and

(6) All eEmissions monitoring and control systems were kept in operation if at all 

possible consistent with safety and good air pollution control practices; and

(7) All of the aActions in response to the excess emissions were documented by

properly signed, contemporaneous operating logs; and

(8) At all times, tThe facility was operated in a manner consistent with good practices 

for minimizing emissions; and

* * *

Response to Comment 8.11: The EPA has no plans to make any changes to the 

language at this time. We believe the language is clear, not contradictory in nature, and 

provides an owner or operator a systematic and thorough approach for establishing an 

affirmative defense in the event of a malfunction that results in a violation of a standard. 

Many of the conditions were modeled after the conditions of the affirmative defense in the 

EPA’s SIP SSM policy, which several states have adopted 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. (See, e.g., State Implementation Plans: 

Policy Regarding Excessive Emissions During Malfunctions, Startup, and Shutdown (Sept. 

20, 1999); Policy on Excess Emissions During Startup, Shutdown, Maintenance, and 

Malfunctions (Feb. 15, 1983)). Other conditions were modeled after a Federal 

Implementation promulgated by EPA. ((40 CFR 50.1312). 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.

8l. Affirmative defense—general comments

Comment 8.12: Commenter 0104 states for the sake of argument that if the EPA 

does have authority to promulgate any type of affirmative defense to penalties for 
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malfunctions, the commenter questions whether there is any basis in the record that the EPA 

has developed for establishing an affirmative defense to an emission standard that is based on 

(a) a 30-day rolling emission rate, and (b) performance already being achieved at older 

plants, rather than emission levels that ought to be expected from new or modified units 

using state of the art pollution controls. The commenter understands that certain acts of God 

or force majeure events may be impossible to anticipate, but it is not clear that the affirmative 

defense discussed in the EPA’s preamble is limited to these extreme circumstances. 

According to the commenter, malfunctions should be of extremely limited duration, and the

EPA has not shown why any malfunction that is serious enough to cause a 30-day rolling 

emission rate to be violated ought to qualify for an affirmative defense. The commenter notes 

that these defenses were originally designed for short-term standards that had to be met every

three hours, not emission limits that are based on much longer compliance time periods.

If the EPA can provide some legitimate rationale for adopting an affirmative defense, 

the commenter suggests that the EPA (1) limit the availability of the affirmative defense to 

true acts of God or force majeure events; (2) provide that the affirmative defense cannot be 

used by a specific facility or company more than once within a set period of time, such as 10 

years; and (3) promulgate specific public reporting and notification requirements for all 

malfunctions and violations of which an operator is aware, including publication on the 

EPA’s website and other means to eliminate the need for any person to submit a FOIA 

request for such a report.

Comment 8.13: Commenters (0091, 0098) note that the EPA’s suggestion that a 

NAP can avoid high emissions related to a malfunction by shutting the NAP down makes 

little sense, given the high emissions associated with shutdowns.

Commenter 0091 states that this approach is not consistent with CAA section 111. 

According to the commenter, neither the NSPS General Provisions nor past EPA practice 

requires a plant to shut down whenever a malfunction results in excess emissions. The 

commenter states that basing NSPS emission limitations on an assumption that a plant will 

shut down during a malfunction is inconsistent with the statutory requirement that NSPS 

reflect emissions that are “achievable” by facilities using the best system of emissions 

control.

Comment 8.14: Commenters (0091, 0093) state that the proposed affirmative 

defense is not a substitute for addressing malfunction events in the performance standards 

themselves. According to the commenters, the EPA acknowledges that the sources subject to 

the Proposed Rule sometimes will be unable to comply with the Proposed Standards because 

of malfunctions, even if their equipment is properly designed and maintained, through no 

fault of the source. The commenters asks that the EPA promulgate a standard of performance 

that eliminates that situation, so that the regulated emission sources will be subject to 

differentiated requirements, achievable with the identified best demonstrated technology, 

during malfunction events, rather than an “affirmative defense.” According to the 

commenters, the criteria to be met and actions taken by the source bear no direct relation to 

the statutory factors for standards of performance under CAA section 111. The commenters 

state that the EPA should set emission standards that are achievable during malfunctions. 

According to the commenter, the Proposed Standards, incorporating the affirmative defense, 
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do not represent emission limitations that have been “adequately demonstrated” to be 

“achievable” through use of the best control technology under CAA section 111(a)(1).

Commenter 0093 suggests that Section 111(h) of the Clean Air Act provides EPA with 

several options for setting standards to be met during periods of startup, shutdown or 

malfunction, including the use of work practices. The commenter believes that the EPA 

should utilize the flexibility accorded to the Agency by various sections of the CAA to 

develop standards that reflect the demonstrated performance that can be achieved during 

periods of SSM with technology that has been adequately demonstrated.

Comment 8.15: Commenter 0100 recommends that the EPA modify the affirmative 

defense provisions so that it is a “rebuttable presumption.” The commenter agrees that some 

form of enforcement discretion is needed for malfunctions, and the commenter supports the 

EPA maintaining a regulatory provision for malfunctions such as an affirmative defense. The 

commenter expresses concern that by labeling this as an affirmative defense, it implies that 

the facility is guilty until proven innocent. The commenter notes that the last sentence in 40 

CFR 22.24(a) states that the “respondent has the burdens of presentation and persuasion for 

any affirmative defenses” while the first sentence in this section states that the EPA has the 

burden of presentation and persuasion. The commenter is concerned that by calling 

something an affirmative defense even before it has been established to be a deviation 

improperly shifts the burden to the facility. The commenter suggests that the EPA establish a 

rebuttable presumption (rather than affirmative defense) where it is presumed that the facility 

did everything in their power to minimize emissions during these events, unless the Agency

proves certain facts that are enumerated in the rules. If the Agency wants to challenge these 

activities, the commenter notes that the burden of proof would be on them to show that the 

facility did not undertake reasonable actions to minimize emissions.

Comment 8.16: Commenter 0091 states that it is unclear how the affirmative 

defense would apply to enforcement actions by state and local governments, or to private 

citizen enforcement actions under CAA section 304. The commenter notes that the preamble 

to the Proposed Rule speaks only in terms of application of the affirmative defense in an EPA 

enforcement action. According to the commenter, an affirmative defense should clearly state 

that it is applicable to enforcement actions by states or citizen-suit plaintiffs, as well.

Comment 8.17: Commenter 0100 notes that it is impossible to eliminate the causes 

for certain malfunctions (e.g., lightning strikes).

Comment 8.18: According to Commenter 0091, the EPA states that in the preamble 

that, if a source cannot prove its entitlement to the affirmative defense, “appropriate penalties 

could be assessed in accordance with section 113 of the CAA (see also 40 CFR part 22.77).” 

76 Fed. Reg. at 63,884 col. 2. The commenter notes that this does not answer the questions 

stated above. Moreover, the commenter notes that there is no “part,” nor section, 22.77 in the 

July 1, 2010, edition of Title 40 of the Code of Federal Regulations (the most recent version 

available for Part 22). The Proposed Rule, according to the commenter, is unclear on this key

issue of what the affirmative defense is intended to cover.

Commenter 0091 disagrees with the conditions of paragraph §60.74a(b) and states 

that it is novel at best for a person to be determined to have acted unlawfully unless the 
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person has submitted his entire defense before he is even notified of a potential enforcement 

action. In many cases, the commenter believes it would be obvious to the enforcement 

authority, based on the kind of short malfunction or deviation report sources already

submitted under many air programs, that an exceedance of the Proposed Standards resulted 

from an unforeseen and unavoidable equipment failure or process upset. The commenter 

further states that it is extremely inefficient and burdensome, for both sources and regulators, 

to require a complete justification of the affirmative defense before the enforcement authority

has indicated any need for further investigation. 

According to commenter 0091, a number of the conditions for establishing an 

affirmative defense use phrases that are subject to a wide range of interpretations, and that on 

their face do not recognize any need for reasonableness or cost-effectiveness. The commenter 

asks, “how will the enforcement authority, or a judge, determine whether ‘proper design’ or 

‘better operation and maintenance practices’ could have prevented a malfunction (section 

60.74a(a)(1)(ii)), whether a recurring malfunction is a result of ‘inadequate design’ (section 

60.74a(a)(1)(iv)), whether repairs were made ‘as expeditiously as possible’ (section 

60.74a(a)(2)), whether the source took ‘all possible steps’ to minimize the impact of the 

excess emissions (section 60.74a(a)(5)), and whether emissions monitoring and control 

systems ‘were kept in operation if at all possible’ (section 60.74a(a)(6))? The commenter 

notes that in many, if not most cases, it may have been possible to avoid the malfunction, or 

to do more to reduce the excess emissions, if the source had spent huge amounts of money or 

had imposed economically impracticable constraints on its operation. The commenter 

believes that the affirmative defense, as proposed, leaves open the possibility that a source 

will be considered to be in violation because the enforcement authority decides that in one or 

more respects it would have been “proper” or “possible” for the source to take further steps 

to prevent or minimize the malfunction. In effect, the commenter states that the EPA or the 

court may impose an extreme version of best demonstrated technology, during malfunction 

periods. At a minimum, the commenter is concerned that the vague and unqualified 

descriptors in the criteria for demonstrating the affirmative defense will inevitably lead to 

varying conclusions as to whether a violation has occurred, resulting in inconsistency from 

one jurisdiction to the next.

According to commenter 0091, several of the conditions for establishing an 

affirmative defense in proposed 40 C.F.R. § 60.74a list numerous items which may be 

appropriate considerations in determining whether excess emissions during a malfunction 

should be considered a violation, but which ought not to be listed as mandatory criteria, all of 

which have to be met in order for an exceedance to be excused. For example, the commenter 

notes that proposed section 60.74a(a)(1)(i) requires that the excess emissions must have been 

“caused by a sudden, infrequent, and unavoidable failure of air pollution control and 

monitoring equipment, process equipment, or a process to operate in a normal or usual 

manner....” The commenter notes that there is no apparent reason why a “sudden” and 

“unavoidable” equipment failure or process upset leading to emissions greater than the NSPS 

should be considered a violation of the standards if it is not “infrequent,” even though it is 

“not part of a recurring pattern indicative of inadequate design, operation, or maintenance” 

and “[c]ould not have been prevented through careful planning, proper design or better 

operation and maintenance practices.” See 60.74a(a)(1)(ii) and (iv).
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According to commenter 0091, proposed section 60.74a(a)(6) requires, as a condition 

for the affirmative defense, that all emissions “control systems were kept in operation if at all 

possible.” The commenter states that the phrase “if at all possible” should not be used 

because it is an extreme term that bears no relation to good air pollution control practices. 

Additionally, the commenter asks that this provision (as well as the “general duty” language 

the EPA proposes to add to the Nitric Acid Plant NSPS, as discussed below), should be

qualified, as the EPA has qualified similar provisions in the NSPS General Provisions in 40 

CFR §60.11(d) and the NESHAP General Provisions in 40 CFR §63.6. According to the 

commenter, these conditions should be qualified with caveats that the operation must be 

consistent with safety and good air pollution control practices, that it does not require the 

source to make further efforts to reduce emissions below what the standards require, and that 

it does not require regular operation of backup or standby pollution control equipment. [As 

noted by the commenter, the EPA agreed (40 CFR §63.483(a), 76 Fed. Reg. 22,566, 22,583, 

22,588 (April 21, 2011)) that it was appropriate to include such a qualifier in comparable 

language in NESHAPs.] The commenter notes that the EPA has long recognized, in the 

General Provisions applicable to NSPS, that it is appropriate to require sources to operate the 

affected facility and related air pollution control technology “to the extent practicable ... 

consistent with good air pollution control practice for minimizing emissions” during SSM 

periods, not “if at all possible.” See 40 CFR §60.11(d). The commenter asserts that the EPA 

cannot abandon those rational approaches and adopt the kind of absolute requirements 

implied by the Proposed Rule, without an explanation of why it is necessary and appropriate 

to do so.

According to commenter 0091, proposed section 60.74a(a)(4) would preclude a 

facility from taking advantage of the affirmative defense if the malfunction involved 

bypassing control equipment or a process and the bypass was not “unavoidable to prevent 

loss of life, personal injury, or severe property damage.” The commenter asserts that this 

language is stated in such strong terms that it may be difficult or impossible for a source to 

demonstrate that it met this criterion, even though bypassing the control equipment or the 

process was an appropriate exercise of good air pollution control practices. For example, the 

commenter notes that a bypass can constitute the best air pollution control practice in 

response to an upset in order to prevent excess emissions, e.g., to avoid fouling of pollution 

control equipment media that in turn would result in reduced pollution control equipment 

efficiency or increased pollution control equipment downtime. According to the commenter, 

there can be substantial room for disagreement about what constitutes “severe” property 

damage. Besides the unclear and subjective nature of these criteria, the commenter notes that 

there is nothing inherent to standards of performance under CAA section 111 that requires a 

source to avoid bypassing control equipment to such a degree. Lastly, it is not apparent to the 

commenter at all why the CAA would disfavor bypassing “a process” in this way.

According to the commenter, under proposed section 60.74a(a)(5), a source claiming 

the affirmative defense must prove that: “All possible steps were taken to minimize the 

impact of the excess emissions on ambient air quality, the environment and human health.” 

In addition to the subjective term “all possible steps,” the commenter notes that this provision 

again presents a disconnect between the absolute and extreme requirement of the affirmative 

defense and the provisions of the CAA designed to attain ambient air quality standards and 

protect human health and the environment. The commenter asserts that the CAA does not 
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require sources to take “all possible steps” to control emissions, even to minimize the impact 

of hazardous air pollutant emissions on human health under CAA section 112(f). In addition, 

it is unclear to the commenter how this criterion for qualifying for the affirmative defense 

differs from proposed section 60.74a(a)(3), which requires that the frequency, amount, and 

duration of excess emissions “were minimized to the maximum extent practicable.” Unless 

the EPA explains what additional showing would be needed by section 60.74a(a)(5), the 

commenter asks that it be eliminated.

According to the commenter, the requirement proposed in section 60.74a(a)(8), that 

the source must show that “[a]t all times, the facility was operated in a manner consistent 

with good practices for minimizing emissions” (emphasis added), could be read to go way

beyond an analysis of why equipment may have malfunctioned and place an overwhelming 

burden on the source to meet a “good practices” standard (undefined) for the whole industrial 

plant or commercial premises. The commenter notes that this factor potentially could allow a 

regulatory enforcement official to judge the entirety of operations at a site against a multitude 

of arbitrary “good practices” and subjectively find the stationary source lacking, thereby 

denying the source the ability to assert an affirmative defense for NSPS applicable to a 

particular operation at the site. If the EPA retains this condition for the affirmative defense, 

of demonstrating operation consistent with good practices for minimizing emissions, the

commenter asks that the Agency clarify that this condition applies to the “affected facility,” 

as that term is defined in 40 C.F.R. § 60.2. If the EPA really does intend for this condition to 

apply to operation of the entire site, and not just “the apparatus to which a standard is 

applicable” (see section 60.2 definition of “affected facility”), then the commenter asks the

EPA to explain why it has the statutory authority to shift the focus of the Proposed Standards 

from the apparatus subject to the NSPS to the plant as a whole.

Commenter 0091 feels that the proposed affirmative defense as written is 

unreasonable and impracticable. The commenter notes that although a source believes it 

qualifies for the affirmative defense, it may be considered to have violated the standards—

and may have to report violations, certify noncompliance, etc.—until there has been an 

enforcement proceeding and the source has successfully asserted the affirmative defense. The

commenter asks that the affirmative defense be substantially modified for it to provide any

significant relief. First, the commenter asks that the affirmative defense state clearly that a 

source that qualifies for the affirmative defense shall not be deemed to have violated the 

applicable standards during that time. If the EPA does that, the commenter notes that it may

be unnecessary to state also that the affirmative defense relieves the source from liability for 

all types of penalties and injunctive relief (save criminal penalties), but that should be the 

clear effect of qualifying for the affirmative defense.

Commenter 0091 states that it is not clear what the affirmative defense covers. In the 

Proposed Rule, the commenter notes that the EPA states that the affirmative defense is “to a 

claim for civil penalties for exceedances of such standards that are caused by malfunction, as 

defined in section 60.2.” Proposed section 60.74a. The commenter asks, “Is the term ‘civil 

penalties,’ which is not defined in the Proposed Rule, intended to apply as well to a ‘civil 

administrative penalty’ imposed by the EPA under CAA section 113(d)? (According to the 

commenter, the term “civil penalty” in other contexts means only penalties imposed by a 

court.) The commenter asks, “does the affirmative defense apply to ‘noncompliance 
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penalties’ under CAA section 120 (which apply, inter alia, to noncompliance with a section 

111 NSPS)? According to the commenter, to meet the purported purpose of the affirmative 

defense, which is to provide relief from emission limitations that cannot be met at times even 

with equipment that is properly designed and maintained (see 76 Fed. Reg. at 63,884 col. 1), 

the affirmative defense would need to apply to civil and administrative penalties, including 

noncompliance penalties.

Response to Comments 8.12-8.18: We agree with the commenters concerning the 

use of “affected facility” versus “affected source.” As a result, the EPA has changed 

“affected source” to “affected facility” within the “general duty” clause for Subpart Ga.

We also agree with the commenter that noted that there is no “part,” nor section, 

22.77 in the July 1, 2010, edition of Title 40 of the Code of Federal Regulations (the most 

recent version available for Part 22). This was a typographical error in the proposed 

affirmative defense language. For the final rule, this reference has been corrected to read 

22.27.

For malfunctions, the EPA is finalizing the proposed affirmative defense language for 

violations of the numerical emission limits that are caused by malfunctions with minor 

revisions as discussed below. 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, section 112, and section 129 rules so as to balance the tension, 

inherent in many types of air regulation, 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) (emissions limitations 

under must both continuously apply and meet minimum stringency requirements, even 

during periods of startup, shutdown and malfunction). Thus, the EPA is required to ensure 

that emissions limitations are continuous. The affirmative defense for 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” limitations, on the one hand, are required, there is also caselaw 

indicating 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 ‘never to be exceeded’ standard currently in 

force.” See also, Portland Cement Association v. Ruckelshaus, 486 F.2d 375 (D.C.Cir. 1973). 

Though intervening caselaw such as Sierra Club v. EPA and the CAA 1977 amendments 

calls into question the relevance of these cases today, they support the EPA’s view that a 

system that incorporates some level of flexibility is reasonable. The affirmative defense 

simply provides for a defense to civil penalties for excess emissions that are proven to be 
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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 holder.” Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977). 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” as 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 district courts 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 determined 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, 

then a penalty is not appropriate and penalty assessment pursuant to the section 113(e)(1) 

factors does not occur. 

In exercising its authority under section 111 to establish emission standards (at a level 

that meets the stringency requirements of section 111), the EPA necessarily defines conduct 

that constitutes a violation. The EPA’s view is that the affirmative defense is part of the 

emission standard and defines two categories of violation. If there is a violation of the 

emission standard and the source demonstrates that all the elements of the affirmative 

defense are met, only injunctive relief is available. All other violations of the emission 

standard are subject to injunctive relief and penalties. The CAA does not require that all 

violations be treated equally. 

Further, a citizen suit claim under section 304 allows citizens to commence a civil 

action against any person alleged to be in violation of “an emission standard or limitation 

under this chapter.” The CAA, however, allows the EPA to establish such “enforceable 

emission limitations.” Thus, the citizen suit provision clearly contemplates enforcement of 

the standards that are defined by the EPA. As a result, where the EPA defines its emissions 

limitations and enforcement measures to allow a source the opportunity to prove its 

entitlement to a lesser degree of violation (not subject to penalties) in narrow, specified 

circumstances, as the EPA did here, penalties are not “appropriate” under section 304. 

The EPA’s view is that an affirmative defense to civil penalties for exceedances 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 malfunctions that could not have 

prevented and were otherwise appropriately handled (as reflected in the affirmative defense 

criteria). The EPA has utilized its Section 301(a)(1) authority to issue regulations necessary

to carry out the Act in a manner that appropriately balances these competing concerns.
Page 64 of 80

The EPA disagrees that 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 

satisfied because 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 group any more or less than would 

litigating the appropriate penalty amount in the penalty assessment stage of a citizen suit 

enforcement action, because the 113(e) penalty assessment criteria and the affirmative 

defense criteria are similar and in fact overlap. For example, 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 the 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, among 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 

planning, 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.

Additionally, the affirmative defense is reasonable. The EPA’s judgment is that the 

affirmative defense criteria capture the appropriate considerations in determining whether 

penalties are appropriate when a violation occurs as the result of a malfunction. As noted 

above, the affirmative defense criteria overlap to some extent with the penalty assessment 

criteria set forth in section 113(e), but are not identical. For example, size of business is one 

of the factors listed in section 113(e), but is not reflected in the EPA’s affirmative defense. 

This reflects the EPA’s view that when a violation is caused by a malfunction, the size of the 

business is not relevant to whether penalties should be excused. If the violation was 

unavoidable and could not have been prevented, the EPA’s view is that it would be unfair to 

impose a penalty no matter the size of the business. 

Further, the EPA disagrees with comments that criticize the affirmative defense 

criteria as being overly vague or unduly restrictive and complex. The EPA believes that 

courts are well equipped and often do evaluate and apply the type of criteria set forth is the 

affirmative defense. Many of the conditions were modeled after the conditions of the 

affirmative defense in the EPA’s SIP SSM policy, which several states have adopted into 

their SIPs. (See, e.g., State Implementation Plans: Policy Regarding Excessive Emissions 

During Malfunctions, Startup, and Shutdown (Sept. 20, 1999); Policy on Excess Emissions 

During Startup, Shutdown, Maintenance, and Malfunctions (Feb. 15, 1983)). We do not have 

any indication that parties to enforcement proceedings have had any significant difficulties 
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applying the terms of these SIP affirmative defenses. In addition, 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. 

The EPA does not find persuasive commenters’ concerns with potential use of the 

root cause analysis against the source. The purpose of the root cause analysis is to determine, 

correct, and eliminate the primary causes of the malfunction and the excess emissions 

resulting from the malfunction event at issue. A source’s ability to do so with the benefit of 

hindsight after a malfunction has occurred does not necessarily mean that malfunction could 

have been predicted or prevented.

8m. Affirmative defense should include startup and shutdown

Comment 8.19: Commenter 0091 states that the EPA offers no defensible rationale 

for excluding startup and shutdown events from the proposed affirmative defense. The 

commenter notes that the EPA has recognized it may not be possible to meet normally

applicable emission limitations during startup, shutdown, and malfunction events for many 

NSPS for decades. According to the commenter, if the EPA does not provide separate 

emission limitations for startup and shutdown of regulated units, and if excess emissions 

from those units cannot reasonably be avoided during a startup or shutdown, not because of 

failure of a process or equipment but because of the nature of conditions while starting up or 

shutting down the source, there is no justification for the EPA not to provide the same kind of 

affirmative defense that it proposes to provide for malfunctions. According to the 

commenter, the EPA offers that startup and shutdown periods at nitric acid plants “generally” 

are of relatively short duration (see 76 Fed. Reg. at 63,883 col. 2) and that the higher 

emissions during startup or shutdown would not cause an exceedance of the proposed 30-day

NOX emission limitation because of that short duration. Even if this assumption is true, the 

commenter states that it would not justify excluding startup and malfunction events from the 

affirmative defense, for those situations where the startup or shutdown event is of such a 

duration or magnitude that it causes an exceedance of the 30-day emission limitation.

Response to Comment 8.19: The EPA is promulgating the affirmative defense for 

malfunctions only, not for periods of startup and shutdown. As explained in the proposed

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 111 does not require that emissions 

that occur during malfunctions be factored into development of CAA section 111 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 111 emissions standards. For these reasons, the EPA does 

not believe it is appropriate to apply the affirmative defense provision to startup and 

shutdown periods. Also see Section V of the final rule preamble.

8n. Notification requirements for affirmative defense
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Comment 8.20: Multiple commenters noted that the notification requirements for 

affirmative defense do not allow sufficient time to provide the documentation required.

Commenter (0091) states that allowing only 45 days to provide the kind of extensive 

documentation required by the affirmative defense, including a completed root cause 

analysis, is unreasonable. According to the commenter, ninety days is the minimum time that 

should be allowed, unless EPA substantially streamlines the criteria for the affirmative 

defense, consistent with these comments. The commenter notes that the proposed 45-day

period for submitting a written report demonstrating that the source qualifies for the 

affirmative defense commences on the date of “the initial occurrence of the exceedance of 

the standard.” This presents several problems to the commenter: much of the required content 

of that written report could not be created until the malfunction event ceased—which could 

be days or even weeks after the malfunction commenced. According to the commenter, this 

could make the amount of time the source would have, in practice, to prepare the report much 

less than 45 days. For the particular emission limitation in the Proposed Rule, which is a 30-

day rolling average, the commenter notes that the source operator often will not know 

whether the malfunction will result in emissions that exceed the emission limit until much 

later, potentially almost 30 days after the malfunction occurred. According to the commenter, 

this makes the proposed requirements to notify the Administrator within 48 hours after, and 

submit a written report within 45 days after, the malfunction commenced virtually

unworkable. The commenter asserts that EPA cannot claim credit for an “affirmative 

defense” that many sources will be precluded from using because of the disconnect between 

the averaging period and the short deadlines for phone/fax and written reporting.

Commenter (0091) states that the provision in the Proposed Rule for requesting and 

obtaining an extension of the reporting deadline of up to 30 days would provide little 

practical relief: the source would have to submit the report within 45 days unless the EPA 

Administrator (or his or her authorized representative) granted the extension request before 

the expiration of the initial 45-day period, which is not likely to happen until shortly before, 

if not after, the report would otherwise be due. At a minimum, the commenter asks that the

rule provide that a request for extension of the reporting deadline that the Agency has not 

acted on within 10 days is considered granted.

Commenter (0091) requests that malfunction reporting be required on a semi-annual 

basis, for malfunctions that occurred during the preceding six months (the same frequency as 

similar reports pursuant to NESHAPs and Title V permit requirements). According to the 

commenter this would enable EPA to review the source’s compliance history and the 

measures being taken to address malfunctions, without imposing unworkable reporting 

deadlines (or potentially encouraging sources to bombard the Agency with reports for 

malfunctions that may not ultimately result in the source exceeding the 30-day average 

emission limitation).

Commenter (0100) suggests the following modifications to the language to make it 

more usable: Faxing is an obsolete technology. The commenter asks that EPA allow 

notification by e-mail or other electronic means. The commenter suggests that EPA consider 

making the following modifications (using underline to show text added) to the regulatory
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language in §60.74a to address the concerns mentioned above and to make an affirmative 

defense a more useful tool.

§ 60.74a Affirmative Defense for Exceedance of Emission Limit During Malfunction.

* * * * *

(b) Notification. The owner or operator of the facility experiencing an 

exceedance of its emission limit(s) during a malfunction shall notify the 

Administrator by telephone, or facsimile (FAX) transmission, or electronic means as 

soon as possible, but no later than two business days after the initial occurrence of the 

malfunction, if it wishes to avail itself of an affirmative defense to civil penalties for 

that malfunction. The owner or operator seeking to assert an affirmative defense shall 

also submit a written report to the Administrator within 45 days of the initial 

occurrence of the exceedance of the standard in § 60.72a to demonstrate, with all 

necessary supporting documentation, that it has met the requirements set forth in 

paragraph (a) of this section. The owner or operator may seek an extension of this 

deadline for up to 30 additional days by submitting a written request to the 

Administrator before the expiration of the 45 day period. Until a request for an 

extension has been approved by the Administrator, the owner or operator is subject to 

the requirement to submit such report within 45 days of the initial occurrence of the 

exceedance.

Commenters (0091, 0095) suggest the following revisions to §60.74a:

(b) The owner or operator of the facility experiencing an exceedance of its emission 

limit(s) during a malfunction must notify the Administrator by telephone or facsimile 

(FAX) transmission as soon as possible, but no later than 2 working days after the 

initial occurrence of the malfunction, if it wishes to avail itself of an affirmative 

defense to civil penalties for that malfunction. The owner or operator seeking to assert 

an affirmative defense must also submit a written report to the Administrator as part 

of the semi-annual periodic report in within 45 days of the initial occurrence of the 

exceedance of the standard in 63.72(a) to demonstrate, with all necessary supporting 

documentation, that is has met the requirements set forth in paragraph (a) of this 

section. The owner or operator may seek an extension of this deadline for up to 30 

additional days by submitting a written request to the Administrator before the 

expiration of the semi-annual reporting 45 day period. Until a request for an extension 

has been approved by the Administrator, the owner or operator is subject to the 

requirement to submit such report within the required timeframe. 45 days of the initial 

occurrence of the exceedance.

Commenter (0095) recommends the immediate notification (within 2 working days) 

requirement as a pre-requisite for asserting the affirmative defense should be eliminated in 

section 60.74a(b) for at least the following reasons and replaced with a semi-annual reporting 

requirement:

 The commenter asserts that it is burdensome and duplicative of emergency response 

reporting requirements under SARA/CERCLA/EPCRA and many state regulations 
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for larger excess emission events; the reportable quantity for excess emissions of NO 

and NO2 from non-combustion sources is 10 lbs.

 According to the commenter, this new requirement will contradict many existing 

reporting rules by requiring the reporting of emission quantities below 

CERCLA/SARA/State Agency Reportable Quantities. Thus, the commenter fears that 

agencies could be flooded with reports of very small excess emissions.

 The commenter notes that the rule structure encourages reporting to the agency even 

if the owner/operator is not sure if an exceedance of an emission limit has occurred 

for fear of not being able to claim the affirmative defense. Thus, the commenter is 

concerned that agency reporting systems will become "clogged" with insignificant 

reports further complicating the ability of all resources to respond to a larger event.

 According to the commenter, the rule is not clear to whom the reports should be 

submitted (e.g., the EPA Regional Office, State or Local Agency, LEPC).

Commenter (0098) is concerned with the requirement that owners and operators of 

NAPs must notify EPA “no later than two business days after the initial occurrence of the 

malfunction.” Due to the 30-day averaging period specified in the Nitric Acid NSPS 

Proposal, the commenter notes that an owner/operator may not realize that there was a 

malfunction within the 30-day averaging period that resulted in “excess emissions” until after 

that 30-day period, which negates the ability to assert the affirmative defense. Further, given 

holidays, the commenter notes that a NAP owner/operator may not become aware of a 

malfunction until longer than two days after the malfunction occurred.

Response to Comment 8.20: We agree with your comments on the notification 

period related to the affirmative defense language. We also agree with your comments 

concerning the reporting requirements. The language has been changed in the final rule at 

paragraph 60.74a(b) to read as follows:

(b) Report. The owner or operator seeking to assert an affirmative defense shall 

submit a written report to the Administrator with all necessary supporting 

documentation, that it has met the requirements set forth in paragraph (a) of this 

section. This affirmative defense report shall be included in the first periodic 

compliance, deviation report or excess emission report otherwise required after 

the initial occurrence of the violation of the relevant standard (which may be the 

end of any applicable averaging period). If such compliance, deviation report or 

excess emission report is due less than 45 days after the initial occurrence of the 

violation, the affirmative defense report may be included in the second 

compliance, deviation report or excess emission report due after the initial 

occurrence of the violation of the relevant standard.

Also in response to the request for electronic means of notification, the EPA 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
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experiencing an exceedance of its emission limit(s) during a malfunction must notify the 

Administrator by telephone or facsimile (FAX) transmission of the exceedance. However, 

the written reports required to demonstrate that the affirmative defense provisions have been 

met and requests for an extension of the deadline for these reports may be submitted 

electronically. 

8o. Root Cause Analysis-suggestions for language changes

Comment 8.21: Multiple commenters (0095 and 0100) suggested revisions to the

root cause language.

Commenter (0095) suggests the following revisions to §60.74(a):

(a)(9) A written root cause analysis has been prepared, the purpose of which is to 

determine, correct, and eliminate the primary causes of the malfunction and the 

excess emissions resulting from the malfunction event at issue. The analysis must 

also specify using best monitoring methods and engineering judgment, the amount of 

excess emissions that were the result of the malfunction.

The commenter notes that EPA should not require preparation and submission of a 

formal root cause analysis as this would have a chilling effect on internal communications 

regarding the root cause investigation and would detract from the goal of ensuring a candid 

inquiry into the event. According to the commenter, the cause of even smaller malfunction 

events is routinely investigated within the industry, and no regulation is necessary to require 

this to happen.

Commenter (0100) suggests modifications to the rule language regarding root cause 

analysis. To many engineers, the commenter notes that the term “root cause analysis” implies 

a formal process. According to the commenter, for many malfunctions, the cause is 

immediately obvious and a formal process for determining the cause is not needed. When a 

malfunction occurs, the commenter notes that the facility is expected to correct the problem 

as quickly as possible and return to their operating window. The commenter states that a

formal root cause analysis is typically limited to very significant events or repeat events. The

commenter notes that the proposed language assumes that all malfunctions are equally

significant and need an identical degree of investigation. The commenter believes that a 

formal root cause analysis should only be used when other reasonable methods fail to show 

what caused the malfunction or when the serious nature of an event might make such an 

analysis necessary. Moreover, the commenter believes that other tools may be more 

appropriate (e.g., failure mode and effect, fault tree, etc.) or more powerful tools may be 

introduced in the future. According to the commenter, the facility is the only one that can and 

should decide what tool to use to determine the cause of the malfunction. The commenter 

states that part of this problem may be in communications. If EPA intends for the facility to 

investigate and fix the problem so that is it less likely to recur, the commenter supports that 

concept but suggests that the Agency use an alternative term that does not carry a specific 

meaning. However, if the Agency envisions a formal process for determining the root cause 

for every malfunction, no matter how simple, the commenter believes this is unnecessary and 

would result in excess efforts with no environmental gains. The commenter suggests that 

EPA consider making the following modifications (using strikeout to show text deleted and 
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underline to show text added) to the regulatory language in § 60.74a to address the concerns 

mentioned above and to make an affirmative defense a more useful tool.

§ 60.74a Affirmative Defense for Exceedance of Emission Limit During Malfunction.

* * * * *

(9) A written root cause analysis report has been prepared, the purpose of which is to 

determine, correct, and eliminate mitigate the primary causes of the malfunction and the excess 

emissions resulting from the malfunction event at issue. Facility personnel will determine the 

appropriate type of analysis required (may include but is not limited to root cause analysis, failure 

mode and effect, fault tree, etc.) to identify the cause of the malfunction. The analysis report shall also 

specify, using best monitoring methods and engineering judgment, the amount of excess emissions 

that were the result of the malfunction.

Response to Comment 8.21: We acknowledge your suggestions for changes to the 

language related to a root cause analysis. However, EPA has no plans to make any changes to 

the language at this time.

We believe the language is clear, not contradictory in nature, and provides an owner 

or operator a systematic and thorough approach for establishing an affirmative defense in the 

event of a malfunction that results in an exceedance of a standard. Many of the conditions 

were modeled after the conditions of the affirmative defense in the EPA’s SIP SSM policy, 

which several states have adopted 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. (See, e.g., State Implementation Plans: Policy Regarding Excessive 

Emissions During Malfunctions, Startup, and Shutdown (Sept. 20, 1999); Policy on Excess 

Emissions During Startup, Shutdown, Maintenance, and Malfunctions (Feb. 15, 1983)). 

Other conditions were modeled after a Federal Implementation promulgated by EPA. ((40 

CFR 50.1312). 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. 

8p. Root Cause Analysis—legal obligation

Comment 8.22: Commenter 0091 notes that the requirement in proposed section 

60.74a(a)(9) that the source prepare a “written root cause analysis...to determine, correct, 

and eliminate the primary causes of the malfunction and the excess emissions resulting from 

the malfunction event at issue” does not implement the statutory criteria for standard-setting

under section 111. The commenter claims that a source could never take advantage of the 

affirmative defense if the source was unable to determine the primary cause of the 

malfunction or was unable to correct that cause. According to the commenter, EPA has

defined a malfunction as an event that is “unavoidable” and unforeseeable, and “not 

reasonably preventable.” Therefore, the commenter expects that in many cases the primary

causes of the malfunction will not be ascertainable, or it will not be possible to identify a way

to ensure the malfunction will not recur. According to the commenter, EPA has long 

acknowledged this reality in the General Provisions applicable to NSPS, which requires that 

written reports of excess emissions include the “nature and cause of any malfunction, if 

known....” (See 40 C.F.R. § 60.7(b)(2)). In addition, requiring the facility to eliminate the 
Page 71 of 80

primary causes of the malfunction, without regard to “taking into account the cost of 

achieving such” elimination and the “nonair quality health and environmental impact and 

energy requirements” associated with its elimination is, according to the commenter,

unreasonable and entirely inconsistent with the criteria for NSPS established under CAA 

section 111(a)(1).

Response to Comment 8.22: A root cause analysis is not required for every

malfunction - - only those malfunctions for which the source chooses to assert an affirmative 

defense. The EPA believes that sources seeking to minimize emissions will endeavor to find 

out what went wrong anytime there is a minor or major malfunction. The facility should 

decide what level of investigation is needed in each instance. We agree with the commenter 

that sources should use appropriate techniques of analysis to achieve the desired results and 

conclusions in the event of a malfunction.

The term “root cause analysis” was used generically to imply an analysis of sufficient 

depth and complexity to indicate whether a malfunction did indeed cause a failure to meet a 

standard, provide sufficient information on the nature and causes of a malfunction to 

determine whether the source had a malfunction that met the definition of a malfunction, and 

whether civil penalties are an appropriate sanction for the violation, if one occurred. The term 

“root cause analysis” is not defined in subpart A (the General Provisions) or in subpart Ga. 

The EPA did not intend to prescribe a specific methodology, given that “root cause analysis” 

is not a defined term in the applicable subparts of Part 60.

9. NSCR Versus SCR Used as NOX Control Device

Comment 9.1: Commenter 0104 notes that based on stack testing and monthly

block averages submitted by nitric acid production facilities around the nation, many

facilities are actually achieving in practice NOX emission levels significantly lower than 

BACT standards. According to the commenter, EPA has presented some evidence suggesting 

that facilities “may be able to achieve the proposed emission limit” using NSCR.

The commenter states that EPA required stack testing in 2010 for twelve nitric acid 

production lines equipped with either SCR or NSCR controls for NOX. Of the six lines with 

SCR, the commenter notes that four reported NOX emissions ranging from 0.04 to 0.46 

lb/ton, well below the standard EPA has proposed. Of the six lines with NSCR, the 

commenter notes that four reported test results between 0.01 and 0.35 lb/ton, and a fifth 

measured NOX emissions at 0.52 lb/ton, just over the proposed limit. If conducted properly, 

the commenter asserts that test results should reflect peak hourly emissions during normal 

operations, i.e., long-term averages should be somewhat lower.

Finally, the commenter notes that the “youngest” plant in EPA’s survey was built in 

2000 and most of the remaining plants are at least 20 years old. According to the commenter, 

it is reasonable to expect any new unit built today to meet or exceed standards that are being 

met by production lines installed decades ago.

Comment 9.2: Commenter 0104 states that EPA’s suggestion that NSCR cannot 

meet or exceed the standard it has proposed is not supported by the record. The commenter 
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notes that the analysis of 2010 stack test results prepared by RTI for EPA found that “[t]he 

lowest NOX emissions (0.01 lb/ton) originated from two high pressure trains ... controlled by

an NSCR.” The commenter also notes that conversely, the highest NOX emissions during 

testing came from PCS Geismar Unit 3, a production line controlled by SCR. After 

comparing data from units with NSCR to those with SCR, the commenter notes that the 

author concluded that “[b]oth abatement technologies are capable of emitting less than 0.05 

lb/ton of NOX; therefore, the type of abatement does not necessarily result in higher NOX

emissions.” Moreover, the commenter notes that two other units equipped with NSCR 

(Dyno-Nobel Deer Island and J.R. Simplot-Helm) achieved monthly block averages between 

0.01 and 0.35 lb/ton of NOX in 2009. 

While EPA has appropriately given weight to long-term CEMS data in developing the 

standard, the commenter notes that the two NSCR-equipped units included in the CEMS 

analysis (Agrium-Sacramento and PCS-Geismar Train 4) may not adequately represent 

performance at other units relying on the same control technology. For example, the 

commenter notes that stack test results from Agrium-Sacramento and PCS-Geismar Train 4 

averaged 0.52 and 0.86 lb/ton, respectively, while results for four other plants with NSCR 

ranged from 0.01 to no higher than 0.35 lb/ton. This discrepancy suggests to the commenter 

that higher NOX emissions from Agrium-Sacramento and PCS-Geismar Train 4 may result 

from circumstances unique to those plants that are unrelated to NSCR performance.

Response to Comments 9.1-9.2: As discussed in the preamble to the proposed rule, 

the EPA chose SCR as BSER for a number of reasons. Based on the emissions data available 

to the agency, emissions from the ICR test plants controlled via SCR were lower than those 

using other technologies. Additionally, SCR was chosen as BSER because it is because it is 

more cost effective than NSCR for control of NOX emissions and it produces minimal 

secondary environmental impacts. 

Also, we evaluated continuous NOX emission data from two plants using NSCR. The 

analysis for Dyno Nobel St. Helens shows a maximum 30 operating day emission rate of 

0.21 lb NOX/ton acid. Also, we had monthly averages from JR Simplot that ranged from 0.15 

lb NOX/ton acid to 0.36 lb NOX/ton acid. Although monthly averages are not directly

comparable to continuous hourly NOX emission data, there is a strong probability that this 

source could comply with 0.50 lb NOX/ton acid. Therefore, the standard of 0.50 lb NOX/ton 

acid limit is achievable for at least some nitric acid production units using NSCR.

Also, the EPA notes that the commenter is referring to emissions levels that were 

achieved during RATA testing. These data are gathered over a short period of time under 

steady state operating conditions and are not directly comparable to long term CEMS data.

Long term CEMS data are more representative of the emissions that occur during normal 

operation.

10. Costs

10a. Marginal Costs and Benefits
Page 73 of 80

Comment 10.1: Commenter 0103 asserts that EPA could have set a more stringent 

revised standard. According to the EPA’s analysis, the commenter notes that the change in 

the performance standard will result in no additional costs for nitric acid producers, new 

monitoring requirements will cost an average of forty-five dollars per ton, but the revised 

performance standard, may result in little to no emission reductions “because the majority of 

control systems installed on future affected facilities would likely result in emissions at or 

below the proposed emissions limit even in the absence of these proposed revisions.” 

Considering only average costs of reduced emissions, the commenter notes that EPA 

set a revised standard without taking into account whether further net benefits might be 

achieved by a more stringent rule. Given EPA discretion, statutory instructions, and 

executive orders, the commenter recommends that the agency use a cost-benefit analysis to 

develop its nitric acid performance standards. According to the commenter, regulation should 

maximize social welfare, and cost-benefit analysis is the best tool that agencies can use to 

achieve that end.

The commenter notes that any revisions to the nitric acid plant NSPS can and should 

be based on a cost-benefit analysis that takes into account the costs of implementing the 

newest and best technologies for NOX emissions as well as the benefits of continued 

reduction and regulation of NOX pollutants. Specifically, the commenter asks EPA to set the 

performance standard at a rate for which the marginal cost of increasing pollution control 

equals the marginal benefit of increasing control.

Comment 10.2: Commenter 0103 states that EPA assessed average costs of 

emissions reductions, but it failed to consider marginal costs. When estimating costs, the 

commenter feels that it is important for the EPA to accurately assess the baseline (i.e., costs 

under existing regulations) and to account for the potential for technological growth. Since 

the EPA originally issued the 1971 standards, the commenter notes that research has 

developed many newer, cheaper, and more effective means to reduce NOX emissions. 

According to the commenter, recent industry information indicates that nitric acid 

plants are fully capable of reducing their emissions to 95 to 98 percent below the 

uncontrolled facility emissions level. The EPA’s analysis considered these current practices 

when determining the burden on the industry of using newer technologies to achieve 

emissions reductions, but the commenter notes that the EPA failed to consider the possibility

that plants could meet the revised standard with existing technology and that further 

reductions may be possible. According to the commenter, this history illustrates the potential 

for industry to adapt to regulatory requirements by finding cheaper, more effective ways to 

comply; in other words, technology can bring down compliance costs over time. 

Comment 10.3: Commenter 0103 suggests that the NOX Budget Trading Program 

could assist the EPA in setting an emissions standard for nitric acid plants that is cost-benefit 

justified. Under a market system like the NOX Budget Trading Program, if the emissions 

budget is set efficiently, the commenter notes that the permit price will equal the marginal 

cost of abatement, which should also equal the marginal benefits of reducing emissions. 

According to the commenter, the benefit of reducing NOX emissions from sources within the 

trading program is roughly $592 per ton. Using this figure as a benchmark, the commenter 
Page 74 of 80

believes that the EPA can approximate the benefits of reducing NOX emissions from nitric 

acid plants, and should design its nitric acid performance standards so that marginal costs 

equal marginal benefits. The commenter notes that the EPA should set the emissions standard 

such that nitric acid plants spend the necessary amount to comply with the regulation, up to 

the cost of the NOX Budget Trading Program permit price. In the Proposed Rule, the 

commenter notes that the EPA estimates only average costs, ignoring both marginal costs and 

marginal benefits of the proposed revision. Before issuing a final rule, the commenter 

believes that the EPA should also estimate the marginal costs of further reduction and 

compare those costs to the marginal benefits of further reduction; it should then set the 

revised performance standard at the level where marginal benefits equal marginal costs.

Response to Comments 10.1-10.3: The EPA has not performed an analysis of 

monetized benefits of NOX reductions in the context of this rulemaking. Such analysis is 

typically performed for rules with larger economic impacts than Subpart Ga. However, we 

note that the cost effectiveness for NOX reductions achieved through this final rule are 

reasonable and supported by previous NSPS for other source categories. See Section VI of 

the final rule preamble for more discussion of the economic impacts of this final rule.

10b. Costing Errors

Comment 10.4: Commenter (0095) states that EPA’s capital cost estimate of

$39,000 for installation of a continuous emissions rate monitoring system is very low, based 

on the commenter’s experience in procuring and installing flow rate monitors, especially on 

existing units. According to the commenter, it is always a challenge to install new equipment 

on existing systems, due to space constraints, alignment with data acquisition system, and 

having to calculate continuous emissions based on existing and new measurement devices.

Comment 10.5: Commenter (0098) suggests that if existing NAPs are forced to 

purchase, install, operate, and maintain a second NOX monitor, or a dual span monitor in 

order to accurately capture emissions at all times (including SSM events), it comes at a 

significant cost. The commenter notes that such costs have not been considered by EPA.

Comment 10.6: Commenter (0098) states that the commenter’s members and their 

consultants have found that contrary to EPA’s $15,000 estimate, a gas flow monitor and its 

attendant equipment and installation costs between $25,000 and $35,000. See Sample Price 

Quote at Enclosure A to the commenter’s letter.

Comment 10.7: Commenter (0098) states that EPA must take “into account the cost 

of achieving [the] reduction” mandated by the new NSPS. According to the commenter, EPA 

must consider all costs of complying with the new NSPS and whether such compliance is 

unduly precluded by such costs, as well as whether such costs unduly preclude future 

development of plants in the regulated source category, and any impacts the cost of 

compliance may have on the supply of the products produced by the regulated source 

category. The commenter states that EPA has failed to meet this statutory mandate and must 

begin its proposal and evaluation thereof anew with accurate cost estimates.
Page 75 of 80

Comment 10.8: Commenter (0098) states that EPA assumed that industry would 

choose not to modify or reconstruct existing NAPS and would construct new plants instead. 

According to the commenter, this error resulted in EPA limiting its consideration of costs to 

the six new NAPs it estimated would be constructed from 2011 to 2016, following the 

promulgation of the new NSPS. The commenter states that at no point in the preamble to the 

Nitric Acid NSPS Proposal or in the supporting materials in the docket did EPA collect, 

evaluate, or consider the cost of compliance on existing sources that subsequently are 

modified or reconstructed in a manner that constitutes a “modification” under EPA’s NSPS 

Subpart A regulations, and thereby subjects those sources to the proposed NSPS under 

Subpart Ga.

The commenter offers the following examples of these omissions below: 

(1) The cost for a NAP with NSCR to make changes to its NSCR or to add to its train 

an SCR in order to comply (and any lost production related thereto); [The commenter also 

notes that existing NAPs likely will have space constraints for the installation of new control 

devices. Further, the existing temperature of the gas stream may limit where an SCR can be 

installed into the process. Moreover, if, based on space issues or where an SCR can be 

installed, the gas stream has to be heated or cooled prior to being introduced into the SCR, 

this will create additional costs and emissions.]

(2) The cost for a NAP to install an extended absorption tower(s) in an attempt to 

increase efficiency and thereby reduce emissions (and any lost production related thereto);

(3) The cost to a producer to abandon a NAP that cannot support the costs of 

compliance (as well as the impact of the loss of such facilities on the nitric acid market and 

the economy generally); and,

(4) The initial and long-term costs of additional labor and raw materials related to the 

installation and operation of larger, better, and/or additional control devices.

The commenter believes that EPA’s failure to consider the costs related to existing or 

modified NAPs’ compliance with the proposed NSPS also may impact its analysis regarding 

new NAPs constructed in the future. According to the commenter, this is because EPA based 

its conclusion that six new NAPs would be constructed between 2011 and 2016 on the 

market growth estimates based on past annual increases (in tons) of nitric acid production. 

The growth estimates were calculated in 2006 (based on estimates for the Greenhouse Gas 

Reporting Rule), and, it appears to the commenter that they were not calculated with any

consideration of potentially negative impact the proposed NSPS for NAPs might have on the 

production. [The commenter notes that EPA appeared to use 2006 estimates instead of 2010 

estimates to reflect actual production.] This in turn, according to the commenter, would 

impact EPA’s projections regarding future construction of new NAPs, and any and all costs 

related thereto.

The commenter asserts that EPA must assess the costs of compliance related to 

existing NAPs that are modified or reconstructed and become subject to the proposed NSPS 

in Subpart Ga. The commenter is concerned that the expenditures and other non-monetary
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costs are not justifiable in light of the infinitesimal decrease in overall NOX emission gained 

by implementing the proposed limit.

Comment 10.9: Commenter (0098) finds EPA’s rationale regarding costs related to 

the control used in newly constructed NAPs is flawed, and EPA failed to properly consider 

monitoring equipment costs.

According to the commenter, in evaluating costs related to the projected six new 

NAPs to be constructed between 2011 and 2016, EPA projected costs as the incremental 

difference between complying with the current NSPS requirements of Subpart G, and 

complying with the proposed new NSPS. The commenter notes that EPA concluded that 

because there are many NAPs currently meeting the proposed emission limit of 0.50 lb 

NOX/tHNO3, there is no incremental increase in control costs for newly constructed NAPs. 

Thus, the only incremental costs to be incurred by the entire nitric acid industry to comply 

with the proposed NSPS, EPA concluded, are those related to the installation of six air flow 

monitors.

According to the commenter, EPA’s decision to calculate the incremental costs of 

compliance from the current Subpart G NSPS to the proposed Subpart Ga NSPS, as opposed 

to calculating the actual costs of compliance with the proposed NSPS, makes little sense in 

light of EPA’s (wrongful) conclusion that no existing sources would be modified or 

reconstructed (and thus never subject to the proposed Subpart Ga NSPS), and that only six 

newly constructed NAPS would be subject to the proposed Subpart Ga NSPS. Thus, the 

commenter believes that EPA calculated costs for a scenario they assumed would never exist.

As EPA has long recognized, the commenter notes that NAPs are not “one-size fits 

all operations.” Instead, the commenter notes that they are finely tuned and designed based 

on desired production and pollution control requirements. The commenter believes that it is 

flawed to conclude in a vacuum that merely because some NAPs have achieved the proposed 

standard in the past that there will be no incremental cost for newly constructed sources to do 

so, particularly given EPA’s estimates regarding the production capabilities of EPA’s 

estimated six new plants. Moreover, according to the commenter, the fact that existing NAPs 

utilize a particular pollution control (e.g., SCR) does not mean that the installation and 

operation of the same type of control for a newly constructed NAP is not a cost of 

compliance for the new NAP.

The commenter notes that EPA concluded that there was no additional cost related to 

the installation of a NOX CEMS because the requirement of a NOX CEMS is included in the 

current NSPS. As above, the commenter asserts that the mere fact that a prior source installed 

a NOX CEMS does not remove the full cost of the installation and operation of this device as 

a cost of compliance for a newly constructed NAP.

Response to Comments 10.4-10.9: The EPA agrees with the commenters that dual 

span monitors should have been included in the cost analyses. See discussion below.

The EPA disagrees with the commenter’s assertion that EPA did not include 

incremental increases in costs because there are many NAPs currently meeting the proposed 
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emission limit of 0.50 lb NOX/tHNO3. The reason that incremental NOX CEMS installation

costs for new plants were not included at proposal is because this equipment and the 

accompanying costs were already included in subpart G. New or modified facilities would 

incur the costs associated with use of a NOX CEMS regardless of whether subpart Ga existed 

or not.

The EPA also disagrees that the costs for the flow rate monitor are incorrect. 

Commenter 0098 supplied cost estimates for purchase and installation of flow monitors in 

the range of $25,000 to $35,000. Purchase and installation costs are typically considered 

capital costs. The EPA estimated the flow meters costs as $39,000 for capital costs and 

$15,000 for annualized costs per plant using the EPA CEMS Cost Model, available at 

http://www.epa.gov/ttn/emc/cem.html. These costs are higher than the commenter’s estimated

costs. Therefore, costs for flow rate monitors have not been changed since proposal. 

However, the proposed costs have been changed to account for one modified source 

and five new sources over the next five year period instead of six new sources over the same 

time period. Revisions include the addition of costs for installation and operation of an SCR 

system for the modified source ($2.7 million capital and $370,000 annualized), costs related 

to Appendix F to account for annual stack testing for all six sources ($72,000 annualized), 

and costs associated with the purchase and installation of a dual span NOX concentration 

monitor for all six sources ($138,000 capital and $53,400 annualized).

At proposal, the capital costs and annualized costs for Subpart Ga were $234,000, and 

$90,000, respectively. The cost effectiveness was estimated at $45 per ton of NOX. 

With the additions discussed above, the resulting total industry-wide final capital 

costs and annualized costs of $3.07 million and $585,000, respectively, remain reasonable

and result in an overall cost effectiveness of approximately $300 per ton of NOX.

Comment 10.10: Commenter (0098) states that EPA’s projected costs fail to 

accurately assess the cost impact of its proposal to require a continuous emissions rate 

monitoring system (CERMS). According to the commenter, EPA’s cost estimates are based 

on its assumption that each newly constructed NAP would be required to install an air flow 

meter only and that existing and installed NOX CEMS would not require modification. 

According to the commenter, this assumption appears to have been driven by EPA’s 

calculation of incremental costs instead of actual costs. Of course, the commenter notes that 

such an assumption makes little sense for a newly constructed facility, which would need to 

install both the NOX CEMS and the air flow monitor. Nevertheless, even assuming the six 

future NAPs already had a NOX CEMS installed, the commenter notes that EPA’s 

assumptions remain flawed.

According to the commenter, the majority of existing NAPs use NOX CEMS 

consisting of one of three analyzer technologies: (1) Chemiluminsescence analyzers; (2) 

Non-dispersive infrared analyzers; or, (3) Fourier Transform infrared analyzers. For the 

majority of NAPs in existence, the commenter notes that these analyzers are equipped with 

only a single span range (which monitor in the 0-500 ppm NOX range, in compliance with 

Subpart G). In order to capture SSM events, as required by the proposed NSPS, the 
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commenter notes that the NOX analyzers will require replacement with dual range analyzers 

because SSM events result in emissions far greater than 500 ppm (producers find result in 

emissions from 2,000 to 5,000 ppm). Further, the new analyzers will be equipped with logic 

that will automatically switch the span range to the higher value so that SSM events (elevated 

NOX readings) are captured. According to the commenter, the purchase, installation, and 

maintenance of dual range CEMS are not included in EPA’s cost considerations. The 

commenter’s members and their consultants have found that the cost to switch a single span 

range analyzer to a dual span range analyzer is between $18,000 and 28,000.

In the more likely scenario, to perform the monitoring EPA seeks, the commenter 

believes that a new NAP would be required to purchase and install a comprehensive and 

integrated CERMS. Commenter members and their consultants have found that installed 

CERMS that would meet EPA’s monitoring requirements for the proposed NSPS range 

between $140,000 and $300,000. [See the Attachment A to the commenter’s letter.]

Although not definitively determined, commenter members have estimated that ongoing 

O&M for a CERMS is approximately $100,000 per year, per NAP.

Comment 10.11: Commenter (0097) states that adding the requirement for 

continuous flow meters also is unnecessarily costly for subcategorized small size nitric acid 

plants and the unnecessary costs to install and maintain them are unjustified.

Response to Comments 10.10-10.11: We acknowledge your comments related to 

cost of CERMS. Much of the costs for CERMS supplied by the commenters related to NOX

concentration CEMS (stack probe, data acquisition and handling systems, etc) are not 

associated with these NSPS revisions. The EPA has made some changes to the cost analysis. 

See memo entitled Impacts of Nitric Acid NSPS Review—NOX (Updated Memo for Final 

NSPS). See also Response to Comments 10.4-10.9. Also as discussed in Section 7, no

subcategorization in this source category is warranted.

11. General Supportive Comments

Comment 11.1: Commenters (0092, 0093, 0095, 0096, 0098) agree with EPA’s 

assertion that an opacity limit is not necessary for facilities. Commenter 0096 states that 

EPA's decision is appropriate since the facility is required to demonstrate compliance with 

NOX using a Continuous Emission Monitor. According to the commenter, the opacity 

requirement is not required as an additional method of demonstrating compliance with a NOX

emission limit.

Response to Comment 11.1: We acknowledge the support for EPA’s decision to 

remove the opacity limit from subpart Ga.

Comment 11.2: Commenters (0092, 0093, 0095, 0098) support EPA’s inclusion of 

EPA Reference Method 7E of Appendix A-4 as an additional method available to sources for 

evaluating performance because it provides affected sources with flexibility in selecting the 

best performance test for its purposes. 
Page 79 of 80

Commenter (0098) states many nitric acid plants have relied upon Method 7E in light 

of a March 2000 EPA determination. Although the commenter does not agree with EPA that

Method 7E must include modifications to address moisture and a NO/NO2 split, the 

commenter nonetheless supports recognition in Subpart Ga of the use of a modified Method 

7E.

Response to Comment 11.2: EPA acknowledges the support for EPA’s decision to 

allow the use of Method 7E in subpart Ga.

12. Wording and Typographic Changes

Comment 12.1: Commenter (0105) questioned the placement of proposed method 

ASTM E1584-00(2005)e1 in §60.17(a)(93), stating that in the 3/21/2011 Federal Register, 

this paragraph was assigned to ASTM D6784-02 (Reapproved 2008) for NSPS Subparts 

CCCC, DDDD, LLLL, and MMMM. EPA has proposed 24 new ASTM methods in other 

proposed amendments {10/9/2008 – 73 FR 59956, 12/28/2008 – 73 FR 78522, 5/3/2011 – 76 

FR 24976}. None of them are ASTM E1584-00 (2005).

Response to Comment 12.1: The incorporation by reference is not official until the 

standards are final. When this rule is finalized, §60.17(a) will reflect the existence of ASTM 

E1584-11. Also note that the standard was revised in 2011 so the ASTM number has changed 

slightly from proposal.

Comment 12.2: Commenter (0098) notes that the proposed definition of “operating 

day” in the proposed §60.71a(c) is missing the word “operated”: a 24-hour period beginning 

at 12:00 a.m. during which the nitric acid production unit [operated] at any time during this 

period.

Response to Comment 12.2: We agree with your recommendation. This change has 

been made to the final standards at Subpart Ga.

Comment 12.3: Commenter (0105) submitted suggested changes to subpart Ga:

Section numbers and headings should be in bold. Some of the Section 

numbers are not underlined with their heading. (May be done when signed document 

is converted to the Federal Register format.)

§60.71a – remove the lettering “(a)”, “(b)”, “(c)”, and “(d)” in front of the 

paragraphs of definitions. The current procedures for the definition section of the 

NSPS subparts are to the words alphabetically, not assigned a specific paragraph 

letter. The older NSPS subparts that have not been modified recently (≈ last 10 years) 

still have the lettering, and when their definition sections are modified the paragraph 

letter is removed and then sorted alphabetically. 

§60.71a – the words being defined should be in italics. (May be done when 

signed document is converted to the Federal Register format.)
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§60.73a – Some of the major parts {(a), (b), (c), and (f)} of this section have 

individual headings which are underlined. The heading for (d) should also be 

underline. A heading should be added to (e) to be consistent for this section. {In other 

subparts, these headings are in italics.}

§60.73a(d)(1) in the last sentence, change “lb NOX /ton” to “lb NOX/ton”. To 

be consistent, the “x” should be capitalized. {Type NOX, then subscript the “X”.}

§60.74a(b) – Can the facility send an email notifying the Administrator of the 

emission exceedance? Most government agencies include emails as part of any FOIA 

review, and therefore have procedures for handling email submittals. 

Communications between government staff and facilities are more likely to be by

email than faxes these days (don’t remove fax from notification option). 

§60.75a(a)(4) in Equation 2 definition for Md, change “lb NOX” to “lb NOX.”.

§60.76a(f)(2), suggest change “section 60.72a(b),” to “§60.72a(b),” to be 

consistent with similar language in the subpart.

§60.77a(b)(3), suggest the following:

change: (3) Reasons for noncompliance with the emissions standard; and 

description of corrective actions taken.

to: (3) Reasons for noncompliance with the emissions standard; and (4) 

Description of corrective actions taken.

§60.77a(f)(2), change “with 60.72a(b),” to “with §60.72a(b),”

Response to Comment 12.3: EPA agrees with many of these recommendations. 

These changes have been made to Subpart Ga where appropriate. Most of the suggested

changes occur when the document is converted to Federal Register format.

The agency understands and appreciates the commenter’s suggestion regarding use of 

electronic mail, but at this time the rule has not been changed to allow it for notification 

purposes. As the agency works through security and routing issues, the rule may be revised 

in the future to allow for electronic mail notification.