Response to Comment Document

                               Nitric Acid NSPS

                              Part 60 Subpart Ga

                                   May 2012
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 Diversity- addendum 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
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 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 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 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 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 applied statistical procedures at proposal to determine the 99[th] 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 99[th] 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.
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 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 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, real-time 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 well-established; 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 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 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.
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 non-arbitrary 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. 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 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 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 Simplot-Helm) 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.
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 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 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 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 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 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 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 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:
         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."
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-HQ-OAR-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.
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 mono-pressure 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 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.
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.
   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:
         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:
   oo 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).
   oo 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, 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:

         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 steady-state 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-HQ-OAR-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 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.
   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 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, mono-pressure 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.
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:
   oo 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
   oo The commenter suggests that the EPA clearly demarcate the conditions that should be characterized as either malfunctions or as startup or shutdown events.
   oo 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.
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-term-average 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.)