Comment Excerpt Number: 1
Comment: The EPA's failure to set MACT standards for all HAPs emitted by area source boilers is unlawful.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. See the response to EPA-HQ-OAR-2006-0790-2473-A2, excerpt 2.
We also note that, in a recent decision by the Court of Appeals for the DC Circuit, the court affirmed EPA's interpretation of the statute to require MACT only for sources that emit the HAP listed in section 112(c)(6) and that are needed to meet the 90 percent requirement of section 112(c)(6).  Desert Citizens Against Pollution v. EPA,  No. 11-1113 (DC Cir., Nov. 9, 2012), slip op. at 8.  MACT is not required for other HAP emitted by a source category.  Id.  We reached the 90 percent threshold in section 112(c)(6) for mercury and POM by setting MACT for these HAP that are emitted by coal-fired area sources, and thus fulfilled our statutory and court-ordered obligation.
Commenter Name: Neil Gormley
Commenter Affiliation: Earthjustice et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2473-A2
Comment Excerpt Number: 3
Comment: The EPA's failure to set lawful CAA §112(d)(2) or (d)(4) standards for all area source boilers not only contravenes the CAA but also the Court order in Sierra Club v. EPA, No 01-1537 (D.D.C.), which provides "EPA shall promulgate emission standards assuring that sources accounting for not less than 90% of the aggregate emissions of each of the hazardous air pollutants enumerated in Section 112(c)(6) are subject to emission standards under section 112(d)(2) or (d)(4) no later than December 16, 2010." (emphasis added).
Response: The commenter does not claim that this issue was not possible to raise at the time of the 2010 comment period and, in fact, the commenter did raise this issue during that period (EPA-HQ-OAR -  2006-790-1982.1, at 2).
In the final rule, we explained that we reached the 90 percent threshold under CAA section 112(c)(6) for mercury and POM by setting MACT standards for coal-fired area source boilers.  We also explained why we set MACT only for mercury and POM from coal-fired area source boilers and set GACT for all other pollutants we regulated.  The D.C. Circuit, in Desert Citizens Against Pollution v. EPA, affirmed that we are not required to set MACT for other HAP emitted by the source category. Slip. op. at 8.  Additionally, we note that the commenter has not provided any information to suggest that we need Hg and POM to reach the 90 percent requirement under CAA section 112(c)(6).
Commenter Name: Neil Gormley
Commenter Affiliation: Earthjustice et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2473-A2
Comment Excerpt Number: 10
Comment: The CAA requires the EPA to set MACT standards for all HAP and all sources within this category. But the standards based on GACT that the EPA has set instead under CAA §112(d)(5) are also arbitrary and unlawful in themselves. As explained in the 2010 comments at 16 - 17, the EPA has arbitrarily failed to consider additional control technologies for oil- and biomass-fired boilers that better serve the pollution-reduction objectives of the CAA.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice. The commenter does not claim that this issue was not possible to raise at the time of the 2010 comment period. In fact, the commenter simply refers back to comments raised in that period. Therefore, the comment is outside the scope of the current reconsideration.
Commenter Name: Joseph Seymour
Commenter Affiliation: Biomass Thermal Energy Council (BTEC)
Document Control Number: EPA-HQ-OAR-2006-0790-2475-A2
Comment Excerpt Number: 4
Comment: The EPA should continue to gather more inclusive, accurate data on biomass fuels, sizes, and technologies before moving forward on increasingly restrictive limits. BTEC recognizes that as an industry, it is a partner in improving air quality and environmental sustainability of energy, and so the organization advocates a ratcheting down of data driven emissions limits over a sensible time period. Such a path could involve biennial reduction goals beginning with the above limits, and then decreasing in a tiered approach based on the data generated from boilers tested in compliance with the new Area Source Boiler Rule. The final regulatory product would allow the marketplace to develop financially feasible emissions control options and limit potentially confusing state and regional balkanized biomass boilers regulations.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
Commenter Name: Pamela F. Faggert
Commenter Affiliation: Dominion
Document Control Number: EPA-HQ-OAR-2006-0790-2424-A1
Comment Excerpt Number: 3
Comment: Retention of Exemption for Natural Gas-Fired Units
We also support the EPA's decision to retain the exclusion for boilers and process heaters that burn natural gas from the Area Source Boiler MACT Rule. The HAP emissions from these units are so low that they are extremely difficult, if not impossible, to accurately measure. These small emissions have not been found to pose risks to public health and the cost of controlling these units will greatly exceed any benefits that may result from such controls.
Response: This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, the EPA thanks the commenter for their support and additional justification.
Commenter Name: Barry Christensen
Commenter Affiliation: Occidental Chemical Corporation (OCC)
Document Control Number: EPA-HQ-OAR-2006-0790-2435-A1
Comment Excerpt Number: 1
Comment: OCC strongly supports the continued exclusion of gas-fired units from this rule.
OCC supports the EPA's conclusion that 90% of urban HAP can be controlled as required by the CAA without the additional control of area source boilers and process heaters fired with gas. Gas-fired area source boilers do not emit significant amounts of any of the urban air toxic pollutants for which area source boilers were listed and accordingly as a source category. Consequently, such boilers should not be subject to this rule. For the same reason, the scope of the exclusion for gas-fired boilers in the final rule should continue to include all gas-fired waste heat boilers (WHBs) as provided for in the final rule.
Response: This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, the EPA thanks the commenter for their support and additional justification.
Commenter Name: Stephen E. Woock
Commenter Affiliation: Weyerhaeuser
Document Control Number: EPA-HQ-OAR-2006-0790-2452-A1
Comment Excerpt Number: 6
Comment: The EPA has assessed emissions from and the cost of controls for gas boilers, and determined to exclude gas-fired boilers from the area source boiler category. Weyerhaeuser agrees with this assessment and supports the EPA's decision.
Response: This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, the EPA thanks the commenter for their support.
Commenter Name: Pamela Lacey
Commenter Affiliation: American Gas Association (AGA)
Document Control Number: EPA-HQ-OAR-2006-0790-2468-A2
Comment Excerpt Number: 1
Comment: AGA strongly supports the EPA's exclusion of natural gas boilers from the Area Source Boiler MACT work practice standards and emission limits under §63.11195 of the March 21, 2011 final rule, which is not affected by the proposed rule. This exclusion for natural gas boilers at small area source facilities is very important to our members. AGA's members could lose customers and revenue if industrial and commercial natural gas customers become subject to more burdensome requirements than the work practice standards required under the rulemaking, because the customers of AGA members would be given an incentive to switch from natural gas boilers to electrical equipment to avoid regulatory burdens. Perversely, such fuel switching away from natural gas to electrical equipment would be detrimental to the environment by increasing emissions at power plants. As we have described in our previous comments in this docket, even if an electric generating power plant combusts clean natural gas rather than coal or oil, it has to combust far more natural gas to serve the same customer energy need than if the customer combusted natural gas directly in on-site equipment. This is due to the large amounts of energy lost when converting natural gas to electricity and when transporting the electricity through transmission lines. And if a customer is in a region with a significant amount of coal fired generation on the grid, the emissions would be even higher. Excluding natural gas boilers from the burdens of the Area Source Boiler Rule will help avoid this unintended consequence.
Response: This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, the EPA thanks the commenter for their support and additional justification.
Commenter Name: Pamela Lacey
Commenter Affiliation: American Gas Association (AGA)
Document Control Number: EPA-HQ-OAR-2006-0790-2468-A2
Comment Excerpt Number: 2
Comment: Applying the Area Source Boiler MACT Rule would not appreciably reduce HAP emissions from these smaller natural gas boilers at area sources. The Agency's data for natural gas-fired units show the overwhelming majority of emissions to be below the level that can be accurately quantified by the available test methods.
Response: This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, the final reconsideration rule excludes gas-fired boilers from the source category being regulated under this action, as has been the case since the 2010 proposed rule.
Commenter Name: Bart Sponsellar
Commenter Affiliation: Wisconsin Department of Natural Resources (Wisconsin DNR)
Document Control Number: EPA-HQ-OAR-2006-0790-2453-A1
Comment Excerpt Number: 3
Comment:  In context of the overall rule requirements and the issues identified for comment, it is apparent that similar boilers and processes are treated differently between the Major and Area Source Boiler Rules. For example, all boilers regardless of size are subject to at least a work practice requirement under the Major Source Boiler Rule. However, the same is not true for area sources where gas-fired boilers are totally exempt. Wisconsin DNR cannot resolve how the same boiler can be treated differently between the two rules. We believe that comments and issues under one rule are applicable to both boiler rules and request the EPA to consider all comments in this context.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. The exclusion of gas-fired boilers from this source category was apparent in the 2010 proposed rule, therefore this issue does not meet the standard for reconsideration under CAA §307(d)(7)(B).
Commenter Name: Paul Noe
Commenter Affiliation: American Forest & Paper Association (AF&PA) et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2426-A1
Comment Excerpt Number: 8
Comment: Due to the uncertainty surrounding the fuel versus waste issue and the proposed revisions to the solid waste definition rule, area sources need the additional time to determine if they are burning solid waste and if they will be covered under the Area Source Boiler Rule or the CISWI Rule. As the EPA has proposed revisions to the NHSM Rule, many sources are not yet sure how their secondary materials will be classified. For example, in some cases a material is being burned that a facility believes should qualify as a fuel but the final NHSM Reconsideration Rule to be promulgated after March 2012 could lead to an opposite determination (concluding the NHSM is a solid waste). Members tell us some of their facilities will prefer to comply under the GACT rule (Area Source Boiler Rule) rather than the CISWI Rule, and therefore the facility will need at least another 12 months after a determination is complete to utilize an alternate fuel to meet the Area Source Boiler Rule tune-up requirements. The proposed amended §63.11223(b)(5), which is applicable to both initial and continuous compliance demonstrations for work practices, requires that the tune-up be conducted "while burning the type of fuel that provided the majority of the heat input to the boiler over the 12 months prior to the tune-up."  The facility also has to state in its NOCS that "No secondary materials that are solid waste were combusted in any affected unit." (§63.11225(a)(4)(iv).) Each of these leads to a timing concern that supports the 3-year compliance timeline for the initial tune-up requirement.
Because resolving the fuel versus waste issue will effectively amend the work practice standard by revising the scope of its applicability, we believe that the EPA would have authority to set the compliance deadline at 3 years after the effective date of the final reconsideration rule. Because of the substantial number of affected units and in light of the ongoing uncertainty on the waste/fuel issue, we believe there is ample justification for setting the deadline at this point. Therefore, we request that the EPA set the compliance deadline for completing the work practice requirements on the date 3 years after the effective date of the final reconsideration rule.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, the EPA disagrees that the initial compliance date for completing the work practice/management practice requirements should be re-set based on promulgation of the final reconsideration rule. We also disagree that sources have endured such uncertainty with regard to the NHSM regulatory action that there is ample justification for extending the compliance date. Relative to the total number of existing sources subject to the Area Source Boiler Rule, only a small percentage will be impacted by the proposed and adopted changes in the NHSM Rule. All sources impacted by the adopted changes will be subject to GACT-based rather than MACT requirements. Compliance is simplified. With the exception of the initial compliance date for existing boilers subject to the tune-up requirement, the initial compliance date for regulatory requirements has been March 21, 2014 since the June 2010 proposal. The EPA is now revising the initial compliance date for existing boilers subject to the work practice or management standard of a tune-up and is allowing additional time to complete the initial tune-up by establishing a date of March 21, 2014 as the initial compliance deadline. This extension should make compliance available to the reclassified sources.
Commenter Name: Stephen E. Woock
Commenter Affiliation: Weyerhaeuser
Document Control Number: EPA-HQ-OAR-2006-0790-2452-A1
Comment Excerpt Number: 4
Comment: Due to the uncertainty surrounding the fuel versus waste issue and the proposed revisions to the solid waste definition rule, area sources need the additional time to determine if they are burning solid waste and if they will be covered under the Area Source Boiler Rule or the CISWI Rule.[1] We note that we raised a relevant issue in our comments on the proposed rule in 2010 to which, to our knowledge, the EPA never responded. That comment concerned needed clarity around the timing of compliance with the Area Source Boiler Rule with respect to changes in fuels as a result of the new NHSM RCRA standard. That concern has borne out.
[1]This is Weyerhaeuser's intention; however, it is a presumption because it will depend on achievability and economic feasibility evaluations with respect to how the EPA chooses to finalize this NESHAP as well as the concurrently re-proposed Non-hazardous Secondary Materials That Are Solid Waste rule and the Commercial and Industrial Solid Waste Incinerator (CISWI) rule (76 FR 80452).
Response: See the response to EPA-HQ-OAR-2006-0790-2426-A1, excerpt 8.
Commenter Name: Robert D. Bessette
Commenter Affiliation: Council of Industrial Boiler Owners (CIBO)
Document Control Number: EPA-HQ-OAR-2006-0790-2443-A1
Comment Excerpt Number: 6
Comment: Due to the uncertainty surrounding the fuel versus waste issue and the proposed revisions to the solid waste definition rule, area sources need the additional time to determine if they are burning solid waste and if they will be covered under the Area Source Boiler Rule or the CISWI Rule. As the EPA has proposed revisions to the NHSM Rule, many sources are not yet sure how their secondary materials will be classified. For example, in some cases a material is being burned that a facility believes should qualify as a fuel but the final NHSM Reconsideration Rule to be promulgated after March 2012 could lead to an opposite determination (concluding the NHSM is a solid waste). Some facilities will prefer to operate to comply under the GACT rule (Area Source Boiler Rule) rather than the CISWI Rule, and therefore the facility will need at least another 12 months after a determination is complete to utilize an alternate fuel to meet the Area Source Boiler Rule tune-up requirements.
Response: See the response to EPA-HQ-OAR-2006-0790-2426-A1, excerpt 8.
Commenter Name: Stephen E. Woock
Commenter Affiliation: Weyerhaeuser
Document Control Number: EPA-HQ-OAR-2006-0790-2452-A1
Comment Excerpt Number: 5
Comment: In some cases, a facility combusts a material it thinks should qualify as a fuel but the final NHSM Reconsideration Rule to be promulgated after March 2012 could lead to an opposite determination (concluding the NHSM is a solid waste). If that unexpected determination occurs, facilities such as ours that prefer to operate complying under the GACT rule (Area Source Boiler Rule) rather than the CISWI Rule will need at least another 12 months after a determination is complete to utilize an alternate fuel to meet the Area Source Boiler Rule tune-up requirements. That is because the proposed amended §63.11223(b)(5), which is applicable to both initial and continuous compliance demonstrations for work practices, requires that the tune-up be conducted "while burning the type of fuel that provided the majority of the heat input to the boiler over the 12 months prior to the tune-up." The facility also has to state in its NOCS that "No secondary materials that are solid waste were combusted in any affected unit." [§63.11225(a)(4)(iv)]. Each of these leads to a timing concern that supports the 3-year compliance timeline for the initial tune-up requirement.
Response: See the response to EPA-HQ-OAR-2006-0790-2426-A1, excerpt 8.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 1
Comment:  NRA has a strong interest in ensuring that processed fats are regulated by the EPA based on the actual HAP emissions from the combustion of the fuel, not for the HAP emissions released from the combustion of other "traditional" petroleum-based liquid fuels. Processed fats are fundamentally different than the "traditional" petroleum-based liquid fuels generated from the physical and chemical refining of crude oil.  The petroleum-based liquid fuels clearly comprise the bulk of the common name subcategory "oil" units or liquid fuel units subject to NESHAP Subpart JJJJJJ.  Processed fats do not inherently contain petroleum products.  The NRA believes that the EPA should determine that processed fats are a separate non-petroleum liquid fuel and that it is both statutorily reasonable and technically appropriate for the EPA to determine that processed fats are not subject to regulation under Subpart JJJJJJ. Specifically, the NRA requests a new processed fats-fired boiler unit definition in Subpart JJJJJJ (much as with gas-fired boilers).
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. We note the proposal for exclusion from the category is incomplete in many respects. The commenter does not provide a basis for distinguishing a boiler capable of burning processed fat-derived fuel from a boiler that otherwise burns petroleum-based liquid fuels. The contemplated subcategory would only be distinguishable based on what fuel is sold to the liquid-fueled boiler. Sources would be capable of switching between subcategories with relative ease, thereby posing compliance assurance difficulties. The EPA is not in a position to adopt the suggested subcategorization as a logical outgrowth of the proposed reconsideration.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 2
Comment: As identified in §63.11195(e), gas-fired boilers as defined in Subpart JJJJJJ are not subject to the rule. NRA believes, as demonstrated through this letter, that boilers at area sources burning processed fats should be similarly defined, analogous to the gas-fired boilers, as processed fats-fired boilers.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
Comparisons to gas-fired boilers could have been raised during the initial rulemaking. The EPA explained the basis for defining gas-fired boilers as not being part of the source category in the proposed rule notice at 75 FR 31900.  In its comments on the proposed rule (EPA-HQ-OAR-2006-0790-0937), the commenter recognized it was covered by this rule but did not suggest it should have been treated in a way that is analogous to gas-fired boilers.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 7
Comment:  The sample set indicates confidence that the metal content of the processed fats samples is insignificant and is comparable to the eight metal HAPs (required under §112(c)(3) of the CAA to be controlled for sources that comprise 90% of the urban HAPs) emitted from gas-fired boilers at area sources that are not regulated under Subpart JJJJJJ (see Table 2).  With a similar minimal metal HAP content to gas-fired boilers, the processed fats-fired boilers do not result in significant metal HAP emissions required to be controlled under Subpart JJJJJJ.  Therefore, processed fats-fired boilers should also not be subject to Subpart JJJJJJ.
Response: See the response to EPA-HQ-OAR-2006-0790-2427-A1, excerpt 2.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 8
Comment: Processed fats are not gaseous fuels, but the Hg content in the processed fats samples was below a 5 parts per billion by weight (ppbw) detection limit. Even if we assume that the Hg was present at this detection limit of 5 ppbw, and we apply a conservative heating value of 17,000 Btu per pound (Btu/lb), this is approximately 3.0E-07 lb/MMBtu  -  an order of magnitude less than the EPA-defined threshold for natural gas-equivalency. Since gas-fired boilers are not subject to Subpart JJJJJJ, the NRA has demonstrated this specific urban HAP (Hg) content identified in various types of processed fats samples analyzed is similar (or less than) in metal HAP content to gaseous fuel, and should be similarly not be subject to Subpart JJJJJJ (exempt from applicability).
Response: See the response to EPA-HQ-OAR-2006-0790-2427-A1, excerpt 2.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 12
Comment: Processed fats contain triglyceride mono, di, and free fatty acids. Acrolein (or 2-propenal) can be formed when processed fats fuel is burned due to decomposition of the triglyceride glycerin backbone. However, this is not a cyclic compound and therefore does not meet the definition of a particulate organic carbon (POC) (or POM). As such, the pollutant generation of these organic HAP from processed fats combustion is analogous to natural gas combustion. The EPA previously found that these emissions were insignificant from natural gas combustion, and a similar argument can be made for processed fats fuel combustion. Processed fats-fired boilers are a requested separate definition under Subpart JJJJJJ, and, similar to gas-fired boilers, are assumed to not emit a significant amount of POM and ethylene dioxide emissions that would require these boilers to be included in the 90% requirement for establishing emission standards under CAA §112(c)(3) for these HAP.
Response: See the response to EPA-HQ-OAR-2006-0790-2427-A1, excerpt 2.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 4
Comment: From the EPA's definition for similar source, a MACT Floor must be established for a source category with comparable emissions. The urban HAP emissions identified in this summary clearly show that boilers that burn petroleum-based liquid fuels are not similar sources to boilers that burn processed fats. HAP emissions from petroleum-based liquid fuels include different constituents and are higher than the HAP emissions from processed fats, which are insignificant, specifically for the 30 statutory targeted HAP emissions required to be controlled under the Boiler MACT. The NRA feels it is both reasonable and necessary for the EPA to separate processed fats-fired boilers at area sources from the list of area source categories contributing to the 90% of urban HAP emissions control requirement under CAA §112(c)(3) for the aforementioned eleven urban HAPs.  Therefore, analogous to gas units, processed fats-fired boilers should not be regulated under Subpart JJJJJJ.
Response: See the response to EPA-HQ-OAR-2006-0790-2427-A1, excerpt 2.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 6
Comment: The NRA is requesting the flexibility to burn small amounts of petroleum-based liquid fuels similar to that allowed for gas-fired boilers, as defined in §63.11237.
Response: See the response to EPA-HQ-OAR-2006-0790-2427-A1, excerpt 2.
Commenter Name: David L. Meeker
Commenter Affiliation: National Renderers Association (NRA)
Document Control Number: EPA-HQ-OAR-2006-0790-2427-A1
Comment Excerpt Number: 10
Comment: Because the metal HAP content (urban HAPs) are frequently non-detect and always much lower than the metal HAP content in gas fuel, processed fats-fired boilers should also be considered insignificant for urban HAP emissions and not subject to Subpart JJJJJJ.
Response: See the response to EPA-HQ-OAR-2006-0790-2427-A1, excerpt 2.
Commenter Name: Dan Bosch
Commenter Affiliation: National Federation of Independent Business (NFIB)
Document Control Number: EPA-HQ-OAR-2006-0790-2428-A2
Comment Excerpt Number: 5
Comment: NFIB suggests that to improve these rules further, the EPA should adopt the suggestions the small-entity representatives provided the Agency during the Small Business Advocacy Review (SBAR) panel held in 2009. These recommendations include:
   * Adopting health-based compliance options in areas where there is no significant risk to nearby residents.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
Commenter Name: Robert D. Bessette
Commenter Affiliation: Council of Industrial Boiler Owners (CIBO)
Document Control Number: EPA-HQ-OAR-2006-0790-2443-A1
Comment Excerpt Number: 10
Comment: Under basic principles of due process and administrative law, the EPA has an obligation to provide the public with a reasonable opportunity to comment on proposed rules. Specifically, Congress requires the EPA to give the public "a reasonable period . . . of at least 30 days" in which to comment on "any regulation" promulgated under the CAA.[5] By the clear terms of the CAA, Congress indicates that 30 days is the minimum time necessary to give the public a reasonable opportunity to evaluate a proposed rule and provide adequate feedback to the Agency. Thus, a comment period meeting the statutory 30-day minimum would be reasonable for a single, ordinary proposed rule. Here, the EPA has violated the clear terms of the CAA and deprived sources of a means to adequately protect their interests and rights in the administrative and judicial processes by providing 60 days of comment for four complex interrelated rules.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. The CAA does not set a requirement for longer comment periods when multiple related rules are proposed. We note that the comment period on the initial rulemaking was 80 days and on the simpler reconsideration it was 60 days.
Commenter Name: Robert D. Bessette
Commenter Affiliation: Council of Industrial Boiler Owners (CIBO)
Document Control Number: EPA-HQ-OAR-2006-0790-2443-A4
Comment Excerpt Number: 1
Comment: In response to our request on the initial rule, the EPA provided additional time for comments. Now on reconsideration, the rules are no less complex, the EPA has added data that must be reviewed for 300 additional sources, and sources face the same pressures of sorting complex data and developing thorough comments that address very technical issues. Although requesting a public hearing would have extended the comment period, we decided our time was better spent in developing comments. There is an extensive amount of data within the docket which will require many hours to sort through in order to produce thorough comments.
Response: See the response to EPA-HQ-OAR-2006-0790-2443-A1, excerpt 10.
Commenter Name: Robert D. Bessette
Commenter Affiliation: Council of Industrial Boiler Owners (CIBO)
Document Control Number: EPA-HQ-OAR-2006-0790-2443-A1
Comment Excerpt Number: 11
Comment: Under reconsideration, the rules are no less complex then when they were first proposed in June 2010. A 60-day comment period is particularly inadequate given their complexity, breadth of applicability, and economic impact. The EPA has added data on reconsideration for 300 additional sources that must be reviewed and sources face the pressures of sorting complex data and developing thorough comments that address very technical issues. Although the EPA released the signed rule proposals almost one month prior to their publication in the Federal Register, it did not provide the majority of the supporting documentation for the proposed rules until publication on December 23, 2011, just two days before the holidays, effectively shortening the comment period.
Response: See the response to EPA-HQ-OAR-2006-0790-2443-A1, excerpt 10.
Commenter Name: Robert D. Bessette
Commenter Affiliation: Council of Industrial Boiler Owners (CIBO)
Document Control Number: EPA-HQ-OAR-2006-0790-2443-A1
Comment Excerpt Number: 12
Comment: The four proposed rules under reconsideration make for an enormously broad and costly  proposal, which would have a significant economic impact across numerous and diverse sector of the US economy, with the Boiler MACT Rule alone imposing capital costs of more than $5 billion and affecting nearly 200,000 sources, according to the EPA. (76 FR 80622.) This economic impact alone, which CIBO estimates to be over $14.7 billion requires a comment period sufficient to ensure thorough consideration of the proposed rules. CIBO joined with 26 other entities and trade associations, representing tens of thousands of affected sources, to ask the EPA to extend the comment period by 30 days and explaining in detail why the extra 30 days was needed and justified. On February 14, 2011, just 7 days before the comments were due, the EPA denied the request.
Response: See the response to EPA-HQ-OAR-2006-0790-2443-A1, excerpt 10.
Commenter Name: Robert D. Bessette
Commenter Affiliation: Council of Industrial Boiler Owners (CIBO)
Document Control Number: EPA-HQ-OAR-2006-0790-2443-A4
Comment Excerpt Number: 2
Comment: Because the EPA only allowed a few weeks, during the holidays, for review of the four proposals before the hearing would have been held, there was effectively less time to sort data in advance of a hearing. We were doubtful that we could have produced enough specific information to have a meaningful discussion by that date.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
Commenter Name: James Johnson
Commenter Affiliation: United States Beet Sugar Association (USBSA)
Document Control Number: EPA-HQ-OAR-2006-0790-2450-A1
Comment Excerpt Number: 8
Comment: The affected boilers used to process sugarbeets are located in agricultural areas of the United States (MI, MN, ND, NE, MT, ID, CO, WY) away from large population centers (see Attachment A). Sugarbeet processing facilities are located near the agricultural fields where the sugarbeets are grown in order to minimize transportation, and thus concerns about HAP emissions from these boilers are minimal and such facilities pose a lower risk to public health. Because of the agricultural and seasonal nature of the sugarbeet processing facilities, there is significant justification for the EPA to distinguish such boilers when finalizing the Boiler Rules. The EPA has previously made distinctions between appropriate controls in areas that are heavily populated and those that are in remote areas when establishing requirements under CAA §112, such as in the Oil and Gas MACT.[9] In making such distinctions, the Agency has acknowledged the differential impacts that can occur from area sources that are located near population centers and near many other sources of HAP. Conversely, in sparsely populated areas where there are few sources of HAP, health impacts from these HAP emissions are greatly reduced. The section of the CAA that addresses area sources, in particular, is heavily focused on population centers. CAA §112(k)(1) requires a finding that "emissions of hazardous air pollutants from area sources that may individually, or in the aggregate, present significant risks to public health in urban areas."[10] It is appropriate, therefore, and consistent with §112(k) for the EPA to regulate those sources located in agricultural areas, especially those classified as area sources, differently from sources located in more densely populated urban centers.
[9] In the preamble to the Oil and Gas MACT, the EPA states, "We agree with commenters that it is reasonable to require a higher level of emission reductions for TEG dehydration units located in more densely populated areas. We also recognize that the oil and natural gas source category is unique because there are many area sources that are located in remote or rural areas. For these reasons and the reasons discussed above, we have subcategorized to differentiate between those sources above the cutoff levels identified above that are inside UA plus offset and UC boundaries and those located outside such boundaries. 72 FR 26, 32 (Jan. 3, 2007).
[10] CAA, §112(k)(1); 42 U.S.C. §7412(k)(1)(emphasis added).
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
Commenter Name: Stephen E. Woock
Commenter Affiliation: Weyerhaeuser
Document Control Number: EPA-HQ-OAR-2006-0790-2452-A1
Comment Excerpt Number: 1
Comment: We presume a biomass-fired boiler at one of these locations that combusts NHSM purchased from off-site generators is subject to this NESHAP (40 CFR 63 Subpart JJJJJJ) as it is not designed or operated as an incinerator, and Weyerhaeuser does not intend to permit and operate the unit under incinerator regulations.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
Commenter Name: Bart Sponsellar
Commenter Affiliation: Wisconsin Department of Natural Resources ( (Wisconsin DNR)
Document Control Number: EPA-HQ-OAR-2006-0790-2453-A1
Comment Excerpt Number: 9
Comment: Wisconsin DNR believes that the EPA does not have the information to characterize and regulate smaller biomass boilers. We believe there is considerable variability in small biomass boiler design, operation, and fuel quality and it is even questionable if these sources can be tuned according to the rule. We suggest that the EPA suspend regulating boilers smaller than 5 MMBtu/hr under this rulemaking and proceed with collecting the necessary information. This threshold is suggested simply because the EPA determined that below this size it is appropriate to reduce the tune-up frequency for oil boilers. In many cases we believe the contaminant content of biomass will be closer to oil than to coal fuels for these small sources. At a minimum, we request that the EPA incorporate rule language exempting sources from measuring CO and O2 flue gas concentrations in cases where it is technically infeasible or it is not pertinent to the boiler tuning over time.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Small biomass boilers were proposed to be subject to tune-up requirements in 2010, therefore the comment regarding suspending regulating such boilers is not appropriate for reconsideration.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 51
Comment: NACAA has reviewed the EPA's Response to Comments submitted in the 2011 rulemaking. We recognize that responding in detail to the many thousands of comments received in that rulemaking would be an enormous undertaking. As a consequence, however, the EPA has not provided a meaningful response to most of the comments submitted by NACAA. This makes it difficult to advance the issues that carry forward from that rulemaking to the present activity.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. As appropriate, we have provided additional responses.
Commenter Name: Neil Gormley
Commenter Affiliation: Earthjustice et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2473-A2
Comment Excerpt Number: 4
Comment: The case for setting MACT standards for oil- and biomass-fired area source boilers is bolstered by the risk that major source boilers may be improperly classified as area sources. See PFPI Comments, Ex. 3, at 3. In practice, there is a great deal of overlap in the boiler capacities of facilities that are major and area for HAP. In their permit applications, facilities often do not demonstrate that they are area sources for HAP, but simply assert it. To the extent that they estimate HAP emissions, they selectively report data. And many facilities use industry generated estimates of emissions factors that are lower -- sometimes by orders of magnitude --  than the AP-42 factors. These facilities evade EPA review of their self-classification decisions. To account for the serious risk of misclassification, the EPA should err on the side of equalizing the emissions standards of major and area source boilers by subjecting area sources to MACT.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. The appropriateness of MACT for all area sources was addressed in the proposed and final rules. Major sources improperly claiming area source status are subject to substantial penalties if discovered. This is a disincentive for the behavior mentioned in the comment. The Area Source Boiler Rule impacts more than 10 times the number of boilers as the Major Source Boiler Rule. Even if every major source were to claim area source status, it would not be rational to impose the burden of MACT on the numerous area sources.
Commenter Name: Neil Gormley
Commenter Affiliation: Earthjustice et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2473-A2
Comment Excerpt Number: 5
Comment: The proposed reconsidered Area Source Boilers Rule fails to set standards for several other groups of area source boilers in violation of CAA §112(c)(6). First, although the rule expands the definition of the biomass subcategory, 76 FR 80532, 80540/3, in order to reduce the number of boilers not falling under any subcategory -- and thus not subject to any standard -- it does not go far enough. The rule still fails to set any standards for boilers burning non-waste, non-biomass secondary materials. This oversight is unlawful and arbitrary. The EPA must either reconfigure the subcategories to encompass all area source boilers or abandon its attempt at subcategorization.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. The EPA does not have information that there are a substantial number of area source boilers that burn non-waste, non-biomass secondary materials without other supplemental fuels, and that would not fall into any of the established subcategories. The commenter does not identify any such boilers, nor does the commenter provide information on whether Hg or polycyclic aromatic hydrocarbons (PAHs) are emitted from such boilers. Even if such boilers were to emit pollutants enumerated in CAA §112(c)(6), the commenter has not provided information as to why these emissions would need to be subjected to CAA section 112(d)(2) or (4) standards in order for EPA to meet its statutory obligations under CAA section 112(c)(6).
Commenter Name: Pilar Rodarte
Commenter Affiliation: Citizen
Document Control Number: EPA-HQ-OAR-2006-0790-2476-A2
Comment Excerpt Number: 2
Comment: I think the proposed amendments could be improved by regulating combustion area sources such as industrial, commercial, and institutional boilers by creating emissions standards based on the type of energy source used rather than the type of facility. I propose that fuel source based emissions standards include not only combustion sources that are coal- and oil‐fired, but also those that use propane. Propane boilers are a large source of NOX and CO, but are disappointingly exempted from the proposed amendments to NESHAP for Area Sources. Emissions standards based on fuel sources supplements the current NESHAP rules for Area Sources and Major Sources and create more effective standards that help create energy efficiency in facilities and the boiler manufacturer industry.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
Commenter Name: James Pew
Commenter Affiliation: Earthjustice, Clean Air Council, Partnership for Policy Integrity
Document Control Number: EPA-HQ-OAR-2006-0790-2480; 2480-A2
Comment Excerpt Number: 1
Comment: Background: Comments Relevant to the Area Source Boiler Rule
The purpose of this submission is to provide the EPA with some information relevant to the boiler and waste rules applicability to biomass burners, using a fairly comprehensive database of recently issued air permits to characterize current trends in the industry. We wish to demonstrate to the EPA that the boiler and waste rules as currently conceived are opening the door to far greater pollution, and more toxic pollution, from the biomass energy sector than is necessary, given the technologies available for emissions control and the reasonable presumption that the public should have that "clean" biomass fuel burned as renewable energy does not consist of toxic waste.
We compiled a database of permits for biomass facilities issued in the last 4 years. All are power producers.
There are 67 new and re-permitted facilities in the database.
Of these 21 are existing facilities that are expanding their existing biomass capacity or adding a biomass boiler; 46 are new facilities. Some of the new facilities have now been withdrawn but were included in the permit database as examples of contemporary permitting practices.
Not every permit or application specifies the type of boiler. Of the ones that are specified, 31 are fluidized bed boilers; 26 are stokers. There are no examples of some of the EPA's categories, e.g. "dutch ovens" or "biomass fuel cells".
Major/minor status of facilities in the database
For the purposes of BACT determination/criteria pollutants, regarding major/minor status:
     1) 3 are not specified
     2) 22 are major sources.
     3) 42 are minor sources. Of these, 29 are synthetic minors.
For the purposes of MACT determination/HAPs,
     1) 7 facilities do not specify whether they are major or area sources (most of these are modifications to add a biomass boiler or expand capacity at an existing facility, and permits do not always specify whether these facilities are currently major sources for MACT).
     2) 9 facilities are major sources
     3) 44 facilities are "area" sources.
Synthetic area sources for HAPs  -  our definition
Of the 44 area source facilities, 32 are what we characterize as "synthetic" minor sources. By this we mean:
      1) the permit either specifies little information about actual HAPs emission rates, but specifies that the facility will emit "less than" 25 tons of all HAPs and less than 10 tons of any HAP.
      2) Or, the permit/application does add up emissions of HAPs with specific emission rates, and miraculously comes in just under 25 tons (it is common for HAPs to sum to 24.9 tons).
      3) Or, the permit/application selectively uses a mix of AP-42 emission factors, National Council for Air and Stream Improvement (NCASI) emission factors, and other industry-provided emission factors to estimate HAPs emission rates, with a sum that comes in just under 25/10 tons. In some cases, NCASI and other industry emission rates are used that are orders of magnitude lower than AP-42 rates. Often the AP-42 rates that are supplanted with industry data are graded "A" for data reliability. Very few if any permits/applications provide justification for using something other than the AP-42 rates.

Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we will not respond to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. This comment provides a summary of permit information for biomass facilities compiled by the commenter.
Commenter Name: James Pew
Commenter Affiliation: Earthjustice, Clean Air Council, Partnership for Policy Integrity
Document Control Number: EPA-HQ-OAR-2006-0790-2480; 2480-A2
Comment Excerpt Number: 2
Comment: The new facilities now being permitted around the country are mostly large, standalone electricity-producing plants. While the "area" source rule would appear to be intended to govern relatively small facilities, the facilities governed by the rule are actually quite large and overlap considerably in size with facilities designated as major sources. The following graph shows the boiler capacity (MMBtu/hr) for "area" and "major" sources in our database. [See submittal for graph of area and major sources capacity.]
Response: This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. While the substance is not a matter for reconsideration, we have previously recognized that there is some potential for overlap in the size of biomass-fired boilers subject to the new source standards under the Major Source Boiler Rule and those subject to the new source standard under the Area Source Boiler Rule. Assuming the commenter has classified major and area source boilers at new units correctly, we note that the graphical information presented by the commenter tends to show that the bulk of what the commenter classifies as area sources tend to be smaller than the mid-range of the major sources. The Agency has set standards for new biomass boilers that reflect GACT for pollutants subject to our CAA §112(c)(3) listing and that reflect what is appropriate for different sized new biomass-fired sources.
Commenter Name: James Pew
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Commenter Affiliation: Earthjustice, Clean Air Council, Partnership for Policy Integrity
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Document Control Number: EPA-HQ-OAR-2006-0790-2480; 2490-A2
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Comment Excerpt Number: 3
Comment: There are at least 16 facilities in the database that plan to burn C&D waste. Some of these specify that only "clean" C&D can be burned. In our review of permits and applications, we found only one fuel sorting study. We analyzed this study and found it to be utterly deficient in terms of the statistical approach used to characterize contamination in the fuel stream (we have attached this analysis). Most if not all facilities with permits allowing burning of C&D do not specify a fuel testing plan; the permits generally say "no burning of treated wood" with no verification provisions.
Of the 16 facilities that plan to burn C&D, 11 are minor sources that will not go through a BACT determination; 7 are synthetic minors for BACT (by "synthetic minor", we mean facilities with a potential to emit that is greater than 250 tons of a criteria pollutant, but the permit caps emissions at 250 tons). Ten are area sources for HAPs, and thus will be regulated under the Area Source Boiler Rule. Of these, 9 are "synthetic" area sources (see above for our definition of a synthetic area source for HAPs).
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we will not respond to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. This comment provides a summary of permit information for biomass facilities compiled by the commenter.
Commenter Name: James Pew
Commenter Affiliation: Earthjustice, Clean Air Council, Partnership for Policy Integrity
Document Control Number: EPA-HQ-OAR-2006-0790-2480; 2480-A2
Comment Excerpt Number: 5
Comment: Emission Control Technologies Now Commonly Used on New Biomass Boilers
PM: What is in General Use
All new and re-permitted facilities in our database use either a baghouse or ESP for PM control. These technologies are assumed capable of removing >99% of PM; baghouse removal rates of 99.9% and above are sometimes promised in air permits.
Not every permit specifies a separate emission rate for filterable PM versus total PM. For those in the database that do (there are 19 of them), values range from 0.0075 to 0.03 lb/MMBtu. In the graph below, red dots designate bubbling fluidized bed boilers or circulating fluidized bed boilers; blue dots designate stokers. Given the similarity of the emission rates, it is not clear why the EPA has designated such a large difference in the between the new unit standard for "wet" stokers (0.029 lb/MMBtu) and bubbling fluidized bed (BFB) boilers (0.0098 lb/MMBtu). These units appear to be using the same technologies and achieving the same emissions rates for PM.  PM emissions at existing facilities are commonly controlled with ESPs and baghouses. Emissions test data from the McNeil biomass plant in Vermont shows that filterable PM can be controlled well.

Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we will not respond to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. This comment provides a summary of permit information for biomass facilities compiled by the commenter.
Commenter Name: James Pew
Commenter Affiliation: Earthjustice, Clean Air Council, Partnership for Policy Integrity
Document Control Number: EPA-HQ-OAR-2006-0790-2480; 2480-A2
Comment Excerpt Number: 6
Comment: Emission Control Technologies Now Commonly Used on New Biomass Boilers
HCl: What is in General Use
Of the 26 facilities in our database of permits for biomass facilities issued in the last 4 years that list HCl emission rates, rates range from 0.00083 to 0.02 lb/MMBtu. There are 36 facilities in the database that list some kind of acid gas control, such as trona injection, trona plus wet scrubber, pulverized limestone injection, dry scrubber, etc. Not all of these specify an actual emission rate however. Many permits that are synthetic area sources for HAPs simply specify that HCl emissions are capped at less than 10 tons per year (tpy), and they basically promise that they will keep adding sorbent until they reduce the emission rate to an acceptable level.  For facilities that do list rates, the red dots in the graph below designate rates at facilities that will use of some kind of acid control.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we will not respond to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. This comment provides a summary of permit information for biomass facilities compiled by the commenter.
Commenter Name: James Pew
Commenter Affiliation: Earthjustice, Clean Air Council, Partnership for Policy Integrity
Document Control Number: EPA-HQ-OAR-2006-0790-2480; 2480-A2
Comment Excerpt Number: 7
Comment: Emission Control Technologies Now Commonly Used on New Biomass Boilers
CO: What is in General Use
The EPA presents CO limits in units of ppm, not lb/MMBtu as they are usually specified in emissions permits. We back-calculated what the EPA's CO limits were in terms of lb/MMBtu (heat input basis) by reversing the formula that the EPA provides for estimating output-based limits from input-based limits, and applying this to the EPA's output-based limits provided in the Major Source Boiler Rule. They are as follows: [See submittal for a table showing EPA's CO emission rates converted to lb/MMBtu (heat input basis)].
All the facilities in our database of points for biomass facilities issued in the past 4 years fall into one of the two highlighted categories (i.e., stokers designed to burn wet biomass fuel and fluidized bed units designed to burn biomass) above.
In our database, there are 50 facilities with permits that specify a CO emission rate, which range from 0.027 to 0.6 lb/MMBtu. CO is very hard to control in biomass burners, but nonetheless, most facilities still claim they will control it using "good combustion practices," There are 9 facilities (marked in red on the graph below) that state they will use an oxidation catalyst for CO control. Many facilities that do not propose to use an oxidation catalyst nonetheless are permitted at CO emission rates similar to those promised at facilities that do use a catalyst.
The stoker and fluidized bed categories are the types of boilers found in the permit database. There is a big difference in the new unit CO emission rates between stoker and fluidized bed boilers in the EPA's rule. The graph below suggests that the stokers with the very lowest CO rates do tend to be fluidized bed units. However, there are a number of BFB boilers that are permitted with CO emission rates considerably lower than the limit of 0.19 lb/MMBtu that the EPA has proposed. Further, while stoker units do appear to be using oxidation catalysts to achieve the lowest rates, there are some stokers that are not proposing to use oxidation catalysts that will achieve a CO rate comparable to a BFB. The bottom line: the EPA's new source performance standards for stokers and BFB's do not appear to represent anything close to the best/lowest rates.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we will not respond to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. This comment provides a summary of permit information for biomass facilities compiled by the commenter.
Commenter Name: Matthew Todd
Commenter Affiliation: American Fuel & Petrochemical Manufacturers (AFPM) and the American Petroleum Institute (API)
Document Control Number: EPA-HQ-OAR-2006-0790-2482-A2
Comment Excerpt Number: 3
Comment: Since a residential boiler is defined as a boiler providing only comfort heat and/or hot water for up to four residential units, we believe a boiler providing comfort heat and/or hot water for an office, workroom, control room, or similar space of similar size should also be exempted. Such small boilers, whether firing gas or liquid, have miniscule emissions and there is no environmental or health basis for imposing any requirements on such small emission sources.
Response: As stated in the preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Boilers at residences were never listed as part of the industrial and commercial/institutional boilers source categories. The commenter does not claim the boilers discussed in the comment are not at industrial or commercial or institutional area sources. While it is possible to develop an infinite number of different subcategories of ICI boilers that could be considered insignificant by themselves relative to their contribution to the CAA §112(c)(3) inventory, we listed the ICI categories because collectively they emitted amounts needed to reach the 90% threshold of that provision.
MACT Floor Analysis Rationale: Use of UPL for setting CO emission limits
Commenter Name: Paul Noe
Commenter Affiliation: American Forest & Paper Association (AF&PA) et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2426-A1
Comment Excerpt Number: 4
Comment: We do not agree with the justification to use a 99% confidence interval for consistency's sake. First, the EPA is not establishing CO CEMS-based emission limits in the Area Source Boiler Rule, it is only giving sources the option to comply with the stack test-based CO limits using a CO CEMS. Second, CO emissions have a much greater degree of variability than other pollutants and sources must certify compliance with the CO limit over all operating conditions except startup and shutdown; therefore, the EPA's CO MACT floor should account for variability to the maximum extent possible. The small amount of data used in the EPA's analysis are not representative of the range of expected operations and true variability that is expected from the best performers. The emissions data used to set the CO limit is based on stack testing performed during maximum load conditions, only providing a snapshot of the day-to-day operations of each source. The reasons for using a 99.9% UPL for setting the CO MACT floor cited in the preamble to the March 2011 Major Source Boiler Rule remain valid:
"For CO, EPA considered several comments from industry and States, which provided both quantitative and qualitative comments on how CO emissions vary with load, fuel mixes and other routine operating conditions.  After considering these comments EPA determined that a 99.9 percent confidence level for CO would better account for some of these fluctuations. While a good deal of CO data are available, at least for some of the subcategories, the data show highly variable emissions that can result from situations beyond the control of the operator, such as fuel moisture content after a rain event, elevated moisture in the air, and fuel feed issues or inconsistency in the fuel.  The higher confidence level selected for CO is intended to reflect the high degree of variability in the emissions." (76 FR 15628.)
Therefore, the EPA should retain the use of the 99.9% UPL for calculating CO limits.
Response: As explained in the December 23, 2011 proposal (76 FR 80537), the 99.9% confidence interval was used in the March 2011 final rule in part because the standards covered periods of startup and shutdown but the data did not reflect CO emissions during those periods. While we finalized work practice standards for startup and shutdown periods, we did not revisit the selection of the confidence interval due to time constraints. The EPA has decided to use a 99% confidence interval given that sources are not subject to the CO emission limit during periods of startup and shutdown. Use of a 99% confidence interval also maintains a consistent methodology with the development of the MACT floors for other pollutants. In addition, operation of a CO CEMS allows sources with existing CO CEMS equipment additional flexibility in meeting the requirements of the rule. The use of a 99% confidence interval is also consistent with that chosen for similar rules, including the Major Source Boiler Rule.
Commenter Name: Lorraine Gershman
Commenter Affiliation: American Chemistry Council (ACC)
Document Control Number: EPA-HQ-OAR-2006-0790-2444-A1
Comment Excerpt Number: 33
Comment: ACC does not agree with the EPA's rationale for reverting to a 99% confidence interval. The EPA states in the reconsideration proposal:
     In the final rule, the EPA selected the use of a 99.9 percent confidence interval for calculating the MACT floor for CO emissions. A petitioner requested reconsideration of this selection given the fact that the EPA used a 99 percent confidence interval for all of the other emission limits in the final rule. The petitioner pointed out that if the data are highly variable, the 99 percent confidence interval should adequately reflect the variability of emissions as well as for the data sets for other pollutants. In the development of the final rule, the 99.9 percent confidence interval was selected in part because the standards covered periods of startup and shutdown, while the data did not reflect CO emissions during those periods. While the EPA finalized work practice standards for startup and shutdown periods, the selection of the confidence interval was not revisited due to time constraints. The EPA is now proposing to use a 99 percent confidence interval in order to maintain a consistent methodology with the development of the MACT floors for other pollutants, and because optional CO CEMS-based limits are being proposed that would allow sources additional flexibility in meeting the requirements of the rule. (76 FR 80536.)
ACC does not agree that a 99% confidence interval must be used for the sake of consistency. Carbon monoxide emissions have a much greater degree of variability than other pollutants and a source must certify compliance with the CO limit under all operating conditions except startup and shutdown; therefore, the EPA's CO MACT floor should account for variability to the maximum extent possible. The small data set used in the EPA's analysis is not representative of the range of expected operations and variability that should be expected from even the best performers. The emissions data is based on stack testing performed during maximum steady state load conditions, only providing a snapshot of the day-to-day operations of each source. As shown below, the reasons for using a 99.9% UPL for setting the CO MACT floor cited in the preamble to the final Major Source Boiler Rule remain valid and the EPA should not adopt the 99% confidence interval to determine the UPL in the reconsidered final rule.
     For CO, EPA considered several comments from industry and States, which provided both quantitative and qualitative comments on how CO emissions vary with load, fuel mixes and other routine operating conditions. After considering these comments EPA determined that a 99.9 percent confidence level for CO would better account for some of these fluctuations. While a good deal of CO data are available, at least for some of the subcategories, the data show highly variable emissions that can result from situations beyond the control of the operator, such as fuel moisture content after a rain event, elevated moisture in the air, and fuel feed issues or inconsistency in the fuel. The higher confidence level selected for CO is intended to reflect the high degree of variability in the emissions. (76 FR 15628.)
Response: See the response to EPA-HQ-OAR-2006-0790-2426-A1, excerpt 4.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 11
Comment: The EPA has studied its approved reference testing methods for years and has amassed significant information about the performance of those methods. Based on this body of knowledge, the EPA reports that, where the result of a test is near the detection level applied, most of its test procedures are accurate to within +/- 50%; at other times the EPA asserts that these tests are accurate to within +/- 15%. Monitoring devices, such as CO monitors, must meet stringent requirements for drift and must be calibrated to within 2% of the full scale value of the expected emission level of the unit. The paired testing data and other data in the record of this case show that, especially at the better performing sources, the variability in Hg and other specific pollutants is quite low. Similarly, years of testing of pollution control devices found in this sector, such as PM controls (fabric filters and ESPs), show highly consistent performance. Thus far, the EPA has not factored any of these facts into its determination of the performance of the best performing units.
In order to evaluate whether the EPA's procedure for calculating variability is appropriate, one first has to examine what "variability" the EPA is calculating and whether it is relevant under §112 or §129. The EPA's procedure involved determining the 99[th] percentile UPL of the difference in performance between all test runs for all units in the top 12%. This calculation improperly combines two factors: (1) the inter-unit difference between the "best performers" and "the best of the best performers" and (2) the expected variability in performance for each of the best-performing units. The EPA does not have the resources to evaluate each of these situations in detail to determine whether the difference represented inherent variability in performance of the unit or is a consequence of factors (such as fuel composition or specific hardware design) that are within the control of the source, and so it simply, and incorrectly, assumes that each of the units within the top 12% is identical and that all of the difference in performance is a "variability" in performance that is essentially random and therefore[10] susceptible to statistical analysis. This can be addressed by normalizing the data so that one only examines the variability in performance.
Response: The EPA chose to address variability using a 99% confidence interval in order to maintain a consistent methodology with the development of the MACT floors for other pollutants, and because optional CO CEMS-based limits allow sources additional flexibility in meeting the rule requirements.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 21
Comment: The EPA has recommended the use of the 99[th] percentile UPL of pre-regulation testing and argued that its use is justified because the Agency adopted the same approach in the medical waste incinerator MACT rule. This rationale does not explain why the EPA believes the 99[th] percentile UPL is appropriate and not the 50[th],[15] 90[th], or for that matter, the 99.99[th] percentile.[16]
The decision matters because with each increase in the "guaranteed" compliance margin, the standard increases, and there comes a point where the compliance margin is so great that sources can merely accept the risk of a failed compliance test rather than reduce emissions. If a source fails a compliance test it will ordinarily be afforded the opportunity for a retest and only if a source has a confirmed deficiency in its control equipment will a modification be ordered. We are unaware of any situation where a source that is willing to make such modifications as are necessary to meet an applicable limit has ever been ordered to permanently cease operation on the basis of a single failed stack test. In contrast, where an excessive compliance margin is provided emission standards can be ineffective.
The degree to which emission tests results can vary are not truly random, but are constrained by the laws of physics and chemistry and, in many instances, the performance of pollution control devices. The EPA's statistical analyses of the data show that, if the data were randomly distributed, there would be a substantial number of instances where emission rates are less than zero. We know that this is not possible and so the data are "skewed" to the right. One method used by statisticians to adjust for this form of distribution is to assume what is known as a log-normal distribution. See Figure 1. With the assumption of a log-normal distribution, one then evaluates the distribution of the logarithm of the number rather than the number itself. The EPA has employed this method in a number of instances.
[15] Civil enforcement of environmental standards is based on a "preponderance of the evidence," which merely requires that a violation be more likely than not (51[st] percentile).
[16] Some in industry have argued that the levels should be set so that there is no significant probability that a facility would fail a compliance test at any point in its useful life.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1 excerpt 11.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 22
Comment: One feature of log-normal distributions is that they have "tails" that become very long as the variance increases. That is, the difference between the mean and the value that represents the 90[th] percentile probability is much greater where one assumes a log-normal distribution than otherwise. However, we know that the emission rate of specific pollutants, such as Hg, can never be larger than the amount of Hg in the fuel and that emission rates are also influenced by the operational characteristics of installed pollution control devices. Yet, the EPA's calculations routinely predict results that are inconsistent with these facts. They also lead to results, cited above, where the performance of the best performing unit is calculated to be worse than the average of the top 12% and where the calculated performance of the best units approximates the demonstrated performance of the worst units. These examples illustrate the point that in order to properly determine whether a particular statistical method is appropriate for a data set, one must determine whether the results of the method employed make sense. We submit that the EPA's decision to use the 99[th] percentile leads to unrealistically large calculated variations in performance of the best performing units, especially where the distribution is assumed to be log-normal and especially where the sample size is small so that relatively large variances are computed.
Fortunately, there are additional facts to help guide the EPA's determination of a standard compliance margin to be applied to all subcategories  -  the compliance obligations and testing conditions that are imposed by the standard.  An equitable balance is struck when the same conditions used to establish the compliance margin are thereafter used to set the compliance obligation (and vice versa). If a source is required to be regularly tested under conditions that represent the 99[th] percentile "worst-case" conditions, then a 99[th] percentile compliance margin might well be appropriate. Additionally, a larger compliance margin is ordinarily appropriate for standards with short averaging periods and CEMS than for standards that have long averaging periods or where compliance is determined by scheduled stack tests conducted by the source.[17] We also agree with the EPA that a larger compliance margin is warranted where the emission limit is at or near the detection limit of the reference method.
[17] We do not intend to suggest that there is widespread cheating during compliance testing. Our point is that the source has substantial prior notice of such tests and is in control of the operating conditions during the test.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1 excerpt 11.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 23
Comment: The EPA observes that standards are to be complied with "at all times," but this is a truism that is not particularly helpful.[18] What are helpful are the provisions in the rules that set out the conditions under which compliance will be determined. In years past, facilities were to be tested under "reasonable worst case conditions." Today, that standard has been reduced to "representative" conditions  -  a phrase that suggests that a compliance margin based on a 99[th] percentile projection[19] of possible emissions may be too large and that industry projections of severe test conditions may be overstated. Moreover, the structure of the compliance obligations itself suggests that the 99[th] percentile may be too stringent. The following factors, among others set out in the proposed rules, bear on a determination of the appropriate compliance margin:
1. For sources that intend to comply with Hg and HCl fuel sampling, the rules require that a source conduct a stack test and demonstrate compliance using 90[th] percentile worst-case fuel (employing Student's t-test to determine that percentile);
2. For other purposes (e.g., PM and CO compliance), the source may select a "representative" operating condition (suggesting that neither a 90[th] percentile nor a 99[th] percentile worst-case test is required for these pollutants);
3. A source whose emissions during a test are less than 75% of the applicable limit is entitled to a reduced frequency of stack testing (suggesting that the EPA does not really believe that replicate testing of sources will vary by more than 33%);
4. Parametric operating limits may not generally be less effective than demonstrated during the stack test (a useful provision, but also one that suggests that the EPA believes that in-use emissions variability is zero);
5. Many of the applicable standards and other requirements contain exclusions from full compliance at all times (e.g., six-minute exclusion under opacity requirements, 5% exclusion for bag leak detection systems);
6. Power (voltage or amperage) to ESPs may not fall to less than 90% of that employed during a stack test[20] (for which we can think of no justification); and
7. Parametric limits are allowed to be based on the lowest (least effective) hourly parameters of the three runs of the compliance test. On its face this will not lead to compliance since it will be less than the average flow rate during the test. Moreover, such parametric limits do not provide any allowance for the variations employed in setting the standard. The EPA should provide that the operating parameters be set at the levels employed during the test run that yielded the lowest emission rate, plus some additional margin to account for in-use variability.
[18] The EPA also asserts that the failure of a compliance test is not a violation of a standard until and unless some governmental authority agrees. We understand the reference in the context of the annual certification of compliance (where the EPA does not intend sources to have to "confess" to a violation of law), but not otherwise.
[19] We understand that a 99[th] percentile UPL is not precisely the same as a 99[th] percentile worst-case condition, but the differences are extremely subtle.
[20] If power to the ESP falls below that employed during the test, PM control efficiency would be reduced. The amount of this reduction is presumably unit-specific and so we can think of no justification for this provision.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1 excerpt 11.
Commenter Name: Neil Gormley
Commenter Affiliation: Earthjustice et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2473-A2
Comment Excerpt Number: 15
Comment: A new emissions limit calculation in the proposed reconsidered Area Source Boilers Rule demonstrates the arbitrariness of the EPA's MACT floor approach. With respect to CO emissions from existing coal-fired boilers, the EPA eliminated certain emissions data from its MACT floor calculations after discovering flaws in that data. (76 FR 80532, 80537/1.) The EPA did not seek to replace this discarded data with accurate data. The result, since the EPA's approach yields higher MACT floors when less data is available, is that the emissions limit will now be substantially higher. The increase from the elimination of just two data points more than offsets a downward adjustment to the UPL. The EPA should not employ a MACT floor approach that yields higher emissions limits when less data is available. Doing so is arbitrary and unlawful. But if the EPA persists in this approach, it must gather more data to replace discarded data rather than increase emissions limits for this reason alone.
Response: EPA reasonably applied the emissions data it had in developing the MACT floor for CO for existing area source coal-fired boilers. The commenter is correct that the Agency did not incorporate into its analysis two data points submitted by the Saint Gobain facility, which appear to have been conducted approximately one year apart. It is not apparent from the information provided to the Agency whether each data point represents a single test run that comprised the entirety of the emission test or whether each data point is the average of three test runs. More importantly, it is also not apparent whether the data were generated using the appropriate test method.  Further, we have no supporting documentation as to the validity/accuracy of the two data points because we did not receive a signed, certified stack test report with the information.  Because we cannot confirm that the two data points were derived using appropriate test methods and we have no associated test reports to review, we did not include the two data points in the MACT floor calculation. The MACT floor calculation includes data on the two best performing sources that we identified based on the data in the record. Each unit in the floor had three test runs for evaluation and as such the calculation resulted in a total of six data points being evaluated.
Commenter Name: Michael L. Krancer
Commenter Affiliation: Pennsylvania Department of Environmental Protection (PA DEP)
Document Control Number: EPA-HQ-OAR-2006-0790-2449-A1
Comment Excerpt Number: 10
Comment: PA DEP agrees that use of the 99% confidence level in setting the CO emission limit ensures that the same approach is used consistently for the development of the MACT floors for all pollutants. However, the EPA excluded the data from a boiler which had completed only two test runs, instead of the requisite three test runs, for measuring CO emissions. Based on the results of the 99% confidence level re-analysis of the data (excluding two test runs for the boiler), the EPA has proposed to increase the CO emission limit for new and existing coal-fired boilers from 400 ppm, corrected to 3% O2, to 420 ppm, corrected to 3% O2. This outcome casts doubt on the validity of the EPA's final analysis of the data set (minus the two test runs) in setting the MACT floor for CO. Therefore, we recommend that the EPA re-analyze the data set and document the rationale for excluding the data from two test runs. If the variability between the two test runs is not significant, the EPA should include the data from these runs in the analysis, especially when the data set for establishing the MACT floor for CO is very limited.
Response: See the response to EPA-HQ-OAR-2006-0790-2473-A2, excerpt 15.
Commenter Name: Lorraine Gershman
Commenter Affiliation: American Chemistry Council (ACC)
Document Control Number: EPA-HQ-OAR-2006-0790-2444-A1
Comment Excerpt Number: 32
Comment: The EPA is proposing to amend the CO emission limit for new and existing coal-fired boilers from 400 ppm by volume on a dry basis, corrected to 3% O2, to 420 ppm by volume on a dry basis, corrected to 3% O2. (76 FR 80536.) This change has occurred for the following reasons:
 The EPA is proposing to remove the test data from the CO MACT floor analysis from a boiler for which only two test runs were completed.
 The EPA is proposing to revise the CO MACT floor analysis to use a 99% confidence interval as opposed to a 99.9% confidence interval to determine the UPL.
ACC supports the EPA's decision to re-evaluate the CO emission limit based on the best available data. ACC agrees with the EPA's rationale to remove the data for the boiler with only two test runs as the required number of test runs for demonstrating compliance is three, and the EPA should include data that best demonstrate variability.

Response: See the response to EPA-HQ-OAR-2006-0790-2473-A2, excerpt 15.
Commenter Name: Neil Gormley
Commenter Affiliation: Earthjustice et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2473-A2
Comment Excerpt Number: 17
Comment: As a practical matter, the EPA's inconsistent approach to identifying the best sources and measuring these sources' performance substantially decreases the protectiveness of its standards. By using different methods to identify sources as best performing on the one hand and to estimate these sources' performance on the other, the EPA selects sources with relatively high variation as the "best"  -  even though these sources would not be labeled best if the Agency ranked them under its own approach to measuring performance. Next, the EPA uses that variability of performance in the sources it picked as best  -  sources that necessarily have higher variability in performance than do the sources that would be "best" under the Agency's own approach to measuring performance  -  to inflate the floors. If the EPA used a consistent approach to identifying the best sources and to estimating these sources' performance, the standards would be far more protective. If the EPA selected as best the sources with the single lowest emission test and then  -  consistent with that approach  -  also measured sources' performance based on their single lowest emissions test, its standards would be far more protective. Likewise, if the EPA identified the best sources based on its statistical analysis of all their emissions tests and  -  consistent with that approach  -  measured their performance the same way, its standards would be far more protective. Only by changing its measurement approach part way through the floor setting process does the Agency arrive at floors that so greatly exceed the actual performance of the relevant best sources.
Response: The EPA disagrees with the commenter that the single lowest emission test should be used to evaluate/identify the best performing unit(s). Multiple test runs are required under EPA's test methods because a single test run does not adequately predict the average performance of an emission unit. The EPA considers the average of the test runs to be a predictor of the performance of the unit. For development of the MACT standard, the overall variability for all units identified as best performing is considered to be representative of the industry data set.
MACT Floor Analysis: Out of Scope
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 5
Comment: No single factor is responsible for the EPA overestimates. In its comments on the 2010 proposal for this sector, NACAA identified several errors in the proposed EPA calculation methodology, including:
     :: use of inconsistent definitions of "best performing unit";
     :: use of the UPL statistical approach for units that are not expected under §112 to currently meet a MACT floor, especially in data sets with small numbers of test results;
     :: treatment of "BDL" emission test results; and
     :: creation of large numbers of subcategories with limited numbers of emission test results.
Response: As stated in the Preamble for the proposed reconsideration of final rule, dated December 23, 2011, we are not obligated to respond on the merits to any comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration.
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Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 10
Comment: In response to comments on the 2010 rule, the EPA adopted a different approach for calculating the UPL to provide for calculation of the "pooled" variability of units in a subcategory, rather than the simple variability of those units. On the basis of this change and without additional notice to interested parties, the EPA then adopted MACT floors that were significantly different from those in the 2010 proposal. On reconsideration, the EPA proposes to use the same procedure as in the final rule. The EPA's misapplication of this new technique leads it to calculate Hg MACT floors for existing oil-fired units that are seven times higher (less stringent) than would have occurred under the 2010 approach and far more lenient than the underlying data would suggest. The EPA states that it is seeking public comment only on the issues specifically identified in its 64-page list of proposed changes and that it will not respond to any comments addressing other aspects of the final rule or any other related rulemakings. However, the EPA also argues that the changes it is proposing are so comprehensive that it should provide a new 3-year compliance period for all sources. While we agree that certain issues, such as "risk-based exemptions," need not be revisited, interested parties have not had an opportunity to comment on the EPA's change in procedure. We think it is unwise for the EPA to suggest that it will not consider any and all comments related to the substance of the rulemaking.
Response: As stated in the preamble for the proposed reconsideration of the final rule, dated December 23, 2011, we are not obligated to respond on the merits to comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, statistical methods for calculating the MACT floor levels have not changed since publication of the final rule in March 2011. Comments raised concerning statistical methods were addressed in the preamble and response to comment document for the March 2011 final rule. The commenter is incorrect with respect to the statement regarding Hg MACT floors for existing oil-fired units. MACT-based Hg standards for oil-fired boilers were not included in the June 2010 proposal or the March 2011 final rule. In addition, we would like to point out that a new 3-year compliance period is not being provided.
Commenter Name: Lorraine Gershman
Commenter Affiliation: American Chemistry Council (ACC)
Document Control Number: EPA-HQ-OAR-2006-0790-2444-A1
Comment Excerpt Number: 17
Comment: EPA Failed to Consider Malfunctions in Establishing MACT Numeric Emission Standards for Hg and CO
Under CAA §112(d)(2), MACT emission standards must be "achievable." Moreover, when the EPA establishes emission standards for existing sources based on the "best performing 12% of units in the category" (the "MACT floor"), those emission standards must on average be "achieved" by the best performers. (See §112(d)(3).) If the EPA is going to require sources to meet a numeric standard at "all times" then the Agency must demonstrate that the standard accommodates the variability in emissions experienced, i.e., "achieved", by best performing sources "at all times," which would have to take into account, among other things, a potential malfunction.
Based on our review of documents in the docket for this rulemaking it appears that the EPA did not consider any data identifying the level of Hg or CO emissions that may result when a best performing source experiences a malfunction. The EPA therefore has failed to show that the Hg and CO emission levels that apply at all times reflect the reductions that are "achieved" by best performing sources during a malfunction.
Despite the fact that the EPA historically has recognized the inherent limits of technology based standards in promulgating standards under both the CAA and the Clean Water Act, in this rule the EPA chooses to ignore the fact that, despite owners'/operators' best efforts, technology sometimes fails and that even a best performing source could experience a malfunction. Because the EPA failed to consider the level of emissions that may result from a malfunction and incorporate that consideration in the numeric standard for Hg and CO, emission standards that apply at all times, the EPA's actions are arbitrary and capricious and not in accordance with law.
Furthermore, the EPA's failure to establish emissions standards consistent with §112 of the CAA also raises the issue of denial of due process. By establishing standards that are not attainable "at all times", the EPA is subjecting roughly 183,000 area sources to potential penalties and worse for failing to comply with numeric emission standards that are unattainable during a malfunction.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: Michael L. Krancer
Commenter Affiliation: Pennsylvania Department of Environmental Protection (PA DEP)
Document Control Number: EPA-HQ-OAR-2006-0790-2449-A1
Comment Excerpt Number: 15
Comment: PA DEP recommends that the EPA re-analyze the data used to establish the MACT floor for CO.
Response: As stated in the preamble for the proposed reconsideration of the final rule, dated December 23, 2011, we are not obligated to respond on the merits to comments addressing aspects of the final rule beyond the topics for which comments were requested. This comment is not on an issue reopened by the December 23, 2011 FR notice and is outside the scope of the current reconsideration. Nevertheless, we would like to point out that the EPA reviewed the data used to calculate the MACT floors prior to the December 2011 proposal. Changes to limits for CO were made accordingly.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 4
Comment: Where the EPA has data from testing at levels of precision sufficient to determine the actual variation in performance of a reasonably significant number of units, and where the Agency's approach to identifying the "best performing units" does not skew the results too significantly, the resulting calculations lead to proposed limits that would lead to significant emission reductions from some of the highly polluting subcategories. However, where these factors are not present, the EPA's procedures and assumptions lead to gross overestimates of the variability in performance of the best performing units and proposed emission limits that are higher than current emissions. Such limits simply create testing and paperwork burdens without providing any public health benefit. Moreover, these limits clearly do not meet the requirements of §112 and are likely to lead to additional litigation that delays reduction in HAP emissions from the entire sector.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 3
Comment: In light of the significant errors related to variability, NACAA strongly recommends that the EPA revisit each of its MACT floor calculations, especially where the proposed floor is so lenient that a large majority of existing sources already meet the limit. We believe the EPA has sufficient information available to correct the errors in its current proposal and issue a final rule on reconsideration in the next few months.

Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: James Johnson
Commenter Affiliation: United States Beet Sugar Association (USBSA)
Document Control Number: EPA-HQ-OAR-2006-0790-2450-A1
Comment Excerpt Number: 11
Comment: In the reconsideration of the Boiler Rules, the EPA has failed to introduce standards that sufficiently take into account the inherent variability in operations. Variability is a known part of operations at facilities with industrial boilers. While the utilization of the UPL does allow for some variability based on stack tests, there are meaningful differences between the results of stack tests, which are conducted at full-load, steady-state operations and real-world operations where fluctuations in operational conditions are the norm. The emission limits in the Boiler Rules consider testing variability but do not reflect operational variability. The D.C. Circuit has held that variability, particularly in emission controls, must be accounted for when setting MACT standards.[11] According to the D.C. Circuit, the CAA's statutory requirements for setting the MACT floor authorize the EPA to set a standard which reflects what the best performing units can achieve under "the worst reasonably foreseeable circumstances."[12] To account for the worst reasonably foreseeable circumstances, the EPA is required to estimate the variability associated with all factors that impact a source's emissions, including operational and fuel factors.[13]
USBSA supports the EPA's exercise of discretion to account for variability in the standard but recommends that the emission limits also reflect operational and fuel variability in addition to the UPL. The EPA properly chose to consider variability in its setting of the MACT floor but did not consider all the sources of operational variability that could be reflected in the standards. The EPA should include these other factors to develop more achievable standards.
[11] See Cement Kiln Recycling Coal. v. EPA, 255 F.3d 855 (D.C. Cir. 2001).
[12] Sierra Club v. EPA, 167 F.3d 658, 665 (D.C. Cir. 1999).
[13] Nat'l Lime Ass'n v. EPA, 627 F.2d 416, 443 (D.C. Cir. 1980).
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 15
Comment: More than any other factor, the EPA's definition of "Best Performing Unit" leads to overestimates of performance of the best performing units. It creates a situation where units with high UPLs are designated as "best performing units" and displace better performing units in the "top 12 percent" category. The EPA is obliged to base the existing source MACT floor on the performance of the "best performing units" and has offered no plausible explanation for its decision.
The EPA has used two (or three) different methods for establishing the "performance" of the average of the best-performing 12%. In selecting the units to be included in the top 12%, the EPA assumed that the performance of those units was demonstrated by the best test result. Thereafter, in calculating the average of the selected units, the EPA assumes that the performance of a selected unit is defined by all test results[6] available for that unit. The EPA then multiplies these results by a fuel variability factor to establish the final number that it uses to calculate the floor. This fuel variability factor is also different for different units, and so, again, the unit with the lowest single test result is not necessarily the "best performer" as used in the EPA's calculations.
NACAA believes that the EPA should use either the best test result for both purposes or use the best average of all test results for both purposes. This use of inconsistent definitions of performance has resulted in at least one MACT floor that is higher than it should be, as units with better average performance over all tests were excluded in favor of other units with a lower individual test result but higher overall emissions. We also believe that use of the average of all test results for an individual unit is an appropriate measure of the performance of that unit, provided that the subsequent analysis of variability does not then treat that average as a single test result. One way to address this issue may be to use the average of all test results to identify the best performing units in the calculation of the average of the top 12%, but then include all test results of the "best performers" in the determination of the potential variability of that average.[7] The identification of the "best performers" should take place after all of the variability adjustments have been made to the universe of "candidate best performers." In this way the MACT floor would not be artificially increased by the use of data from sources that are ultimately not the best performers within a subcategory.
[6] The EPA includes all test results of "best performers" in its calculation of the MACT floor for each subcategory. This effectively over weights the contribution of sources that have been tested multiple times compared to those that may have been tested only once.
[7] This is not the same as using the 99[th] percentile UPL of the individual runs as a factor to multiply the average.
Response: See the responses to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10, and EPA-HQ-OAR-2006-0790- 2450-A1, excerpt 11.
Commenter Name: Neil Gormley
Commenter Affiliation: Earthjustice et al.
Document Control Number: EPA-HQ-OAR-2006-0790-2473-A2
Comment Excerpt Number: 14
Comment: The EPA may not simply assume that the best performing sources have highly variable emissions. As the D.C. Circuit has instructed, the EPA must point to substantial record evidence "that the best performing sources ever experience a wide range of variability at all." Sierra Club v. EPA, 479 F.3d 875, 881 (D.C. Cir. 2007) (quoting Cement Kiln Recycling Coal. v. E.P.A., 255 F.3d 855, 865 (D.C. Cir. 2001)). The EPA must base its conclusions about variability on substantial evidence, not assumptions. Because the EPA's statistical approach to variability is arbitrary and unlawful, the EPA should instead set MACT floors at the level of emissions reflected in the data that the EPA has.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 16
Comment:  In the development of the 2004 rule for this sector, the EPA determined the base performance level of the median unit in the top 12% and then applied a variability factor that was calculated on the average of the variance in performance for all units with similar pollution technologies. The U.S. Court of Appeals determined that the EPA's method for identifying the base performance level was inappropriate, but did not opine on the method for determining the variability factor.[8] In developing the 2010 final rule, the EPA attempted to calculate the anticipated variation in performance of each of the units in its "best performing" group on an individual unit or subcategory basis. Rather than simply determining the variance in performance, the EPA chose to calculate the UPL of the best performing units, that is, the emission level that each unit in the top 12% could be expected to meet at a 99[th] percentile confidence level. The EPA's procedure also errs by attempting to determine the emission level that the bottom half of the top 12% will meet 99% of the time. However, the EPA should not expect these units to meet the MACT floor limit since nominally half of the top 12% do not meet the average and therefore are not complying units.[9] The development of a compliance margin should be limited to an evaluation of the variability of the top 6% performing units under the compliance conditions imposed by the regulation.
[8] It did agree that the EPA could apply a variability factor to take into account expected variation in performance of such units.
[9] Those units in the top 12%, but with emission levels greater than the average of the top 12% (i.e., the 6[th] through 12[th] percent best performers), do not "comply."
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 1
Comment: Under §§112(d)(2) and 129(a)(2) of the CAA, emission limits for existing sources must reflect the maximum degree of reduction in emissions that the EPA Administrator determines is feasible (Maximum Achievable Control Technology or "MACT") and shall not be less stringent than the average emission limitation achieved by the best performing 12% of sources (for which the Administrator has emissions information) (the "MACT floor"). The EPA concludes that recent court decisions require that (a) floors for existing sources must reflect the average emission limitation achieved by the best-performing 12% of existing sources; (b) a MACT floor cannot be "no control"; (c) the EPA cannot ignore non-technology factors that reduce HAP emissions and (d) the levels of HAPs in fuels consumed by sources must be reflected in the MACT floor determination.[1]
[1] A source that is a low emitter because of low levels of HAP in its fuel can still be a "best performer" whose emission levels are part of the "average of the best performing 12 percent."
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 2
Comment: The EPA has proposed to use an array of calculations, adjustments and defaults to determine the new and existing MACT floors and has provided most of the calculations underlying its proposed floors. Our review of the detailed calculation process leads us to conclude that the EPA's approach is flawed in several significant respects and in almost every instance overstates the variability in emissions performance that is shown in the EPA's data set and other readily available information. These inflated calculations have resulted in the establishment of excessively lenient MACT floors. Ironically, for a few subcategories, the EPA inexplicably failed to provide any allowance for variability or arbitrarily assigned a variability that is far too low to account for expected operational differences in performance over time.

Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 14
Comment: The following discussion sets out our best understanding of the relative impacts of several EPA choices on the overall effectiveness of the resulting MACT floor for other subcategories. We have included herein and attached as Appendix 1 a series of charts setting out the EPA's test data as provided as appendices to its MACT floor memo for each unit, along with the EPA's proposed limit for the applicable subcategory. These charts provide a basis for the assessment of the effectiveness of the proposed limit. The EPA's appendices included only the "lowest test result" for a given unit rather than all test results. In most instances, the difference in effectiveness is minimal, as most sources were only tested once, so the "lowest test result" is also the highest test result. Where a significant number of units were subjected to more than one test, we have also produced a chart including all test results for the top 12% to assist in gauging the effectiveness of the proposed limit. We encourage the EPA to produce similar charts, including all test results, for all units for the rules it ultimately adopts.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 17
Comment: The first step in any scientifically sound measurement process is to ensure that the procedures employed are sufficiently precise to determine meaningful differences. In response to questions from industry as to whether they should extend sampling periods to ensure more precise results, the EPA advised them that they did not need to and that the Agency would address it the final rulemaking. The EPA defines the method detection limit as, "the minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater than zero and is determined from analysis of a sample in a given matrix containing the analyte." Where the "adjusted" average emissions of the top 12% is "near" the method detection level, the EPA now proposes[10] to increase the calculated average so that the floor is not less than 300% of the detection level. To justify this increase the EPA observes that when measurements are near the detection level the measurement uncertainty can be as high as (+/-) 40%, while such uncertainty is reduced to (+/-) 15% if the measured value is three times (300%) the detection level. However, since such measurement uncertainties are necessarily part of the overall variability determined in step one of the EPA's procedure, there is no need or basis to substitute this arbitrary figure for the actual emission data that the statute requires be used. Additionally, it also makes no technical sense to introduce a known error of 300% in the MACT floor in order to avoid a possible error of 25%[11] in any individual measurement. This step constitutes yet one more bias in favor of allowing higher levels of HAP emissions. In this rulemaking the EPA proposes to compound this error by "adjusting" the detection level reported by the laboratory in accordance with established protocols, even where the EPA has no information that the detection levels reported by the laboratory are incorrect.
 [10] The EPA employed this technique in the Cement Kiln NSPS Rule.
[11]This is the difference between the potential error at the detection level and that at three times the detection level.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 20
Comment: The EPA has the means to objectively evaluate requests for subcategories and should do so for all subcategories incorporated in its rule. It should determine through the use of statistical techniques, such as a t-test of significance, that the emissions performance of each proposed subcategory is in fact significantly different from the broader category or subcategory of which it is a member. If a significant difference is shown, the EPA should determine whether the difference is a function of the design of the combustion unit itself or is related to the prevalence of post- combustion controls that can be employed throughout the category. Where the EPA determines that the emissions performance of the proposed subcategory is, in fact, significantly different from the broader category and is associated with the design of the combustion chamber itself, rather than post-combustion controls, the EPA should compute the arithmetic average of the best performing unit(s). However, unless the proposed subcategory has sufficient data (nominally 50 data points) upon which to determine the variability of performance, the EPA should apply the variability factor from the broader category to the arithmetic average of the best source(s) in the new subcategory. Where the EPA did not collect emissions data from a representative sample of all units within a proposed subcategory, the EPA has no basis to assume that any particular unit is in the top 12% of that subcategory. It is therefore insufficient to establish a subcategory on the basis that a particular unit's emissions are greater than the top 12% of the broader category.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 27
Comment: In the absence of sufficient data to make determinations of the variability of individual units and subcategories with limited data, the EPA should develop a reasonable compliance margin to apply to the best-complying sources. The underlying issues are sufficiently complex that, in the absence of truly comprehensive data, no single analysis will likely prove to be dispositive. For this reason we recommend that the EPA perform a series of analyses and examine the central tendency of the results of those analyses. From these results the EPA can establish one or more default variability factors to apply where the limited number of test results affects the calculation of variability in a given subcategory. One such group of analyses, but by no means the only approach that could prove useful, is to start with the most comprehensive data set to determine a broad "default" variability factor and examine more specific data sets to determine whether a more limited variability factor can be assigned based on the data available.[27] Such an approach could proceed as follows:
     :: Commence the process by identifying all units that may reasonably be found to be in the top 12%. This might include the top 25  -  33% of units based on their mean test result and all units whose mean test emissions are within an order of magnitude of the best performing unit.
     :: Calculate the nominal "performance" of each unit; by summing the mean and one standard deviation[28] of the unit specific data.
     :: Average the performance of the top performing 12%, understanding that this is likely an overestimate, based on the low number of test runs for most units.
Since this approach is likely to overestimate the variability to some degree, the results of the first assessment should be considered an upper bound of potential MACT floors. The EPA should then look to see if the variability of the broad group is less than that calculated above.
     :: Using the pool of "best performers" identified above, normalize the emission test results for all sources for which the EPA has data, including those not in the top 12% and determine the average variability in the performance for the broad group. The EPA could accomplish this by dividing the variance for each unit by the mean of the data for that unit and average the results, not the UPL. It has been argued that sources in the top 12% have less variability than the population at large and so this variance should be considered to represent an upper bound of a permissible variance.
     :: Repeat the above-described analyses for the three basic subgroups  -  solid, liquid and gas.
This then would form a second set of possible default variability factors for the subgroups for which sufficient data are available. Since there are more tests available for the entire liquid-fired set of units, it may prove possible to develop a separate variability factor for liquid-fired units, which, while likely larger than that for the best performing units, is more accurate than that based on limited data for the best performing units.
     :: Repeat the above-described analyses using data for the top best-performing, 50%, 25%, 12% and 6% of the basic subgroups. Employ these results if the average variance is less than that for the larger group or if it can be established that the calculated increase in variance is due to differences in performance and not the consequence of the reduced sample size. Iteration in this fashion should identify a point where the reduction in sample size outweighs the improvements normally expected from better performing units.
     :: For purposes of determining the arithmetic average, results reported at a detection limit should be employed as recorded, however, for purposes of determining variance such results should be excluded as they artificially reduce the variance.
     :: For purposes of determining the arithmetic average of the best performing top 12%, all test results should be employed to identify the best performers, not the best single result. This will increase the arithmetic average, but is a more reasonable estimate of the performance of units with multiple tests than the lowest single result currently employed by the EPA.
     :: Once the variance of the data has been determined, it should be applied to the arithmetic average of the top 12%, not to any unit in the data set. Consistent with most of the enforcement expectations, we recommend that it be applied at the 90[th] percentile level.
     :: For those subcategories where the data are sufficiently robust, a variability factor specific to the subcategory may be applied; for all others the applicable MACT floor would be the arithmetic average of the data for the subcategory, as adjusted by the applicable default variability factor.
     :: Where a source or group of sources wishes to maintain that a different variability factor should apply, those parties should be responsible for providing sufficient data to develop a factor that is not dominated by the paucity of data.
     :: Additionally, the EPA could determine the "normalized" variance for each unit where more than a certain number of tests (perhaps 10) are available and average those values.
The EPA should examine the performance of similar units in the EGU sector and other sectors and review relevant BACT and lowest achievable emissions rate (LAER) determinations. The EPA should also examine the overall distribution of the data set at issue to determine a reasonable variability factor. Where there are a large number of units with similar emission levels, a large variability adjustment should not be applied.
Where the EPA determines that a source category's emissions are highly variable over a short period (e.g., CO), the EPA should consider longer averaging periods, such as 30-day rolling averages, that reflect and accommodate this form of variability, while still preserving the environmental benefits the CAA contemplates. However, under no circumstances should 30-day CEMS-based limits be higher than the corresponding reference method (3-hour) limit.
[27] We have not conducted these sorts of analyses and have no way of anticipating their results.
[28] It may be more appropriate to use Student's t-test at a similar level of confidence.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 30
Comment: The EPA's approach to "rounding" introduces an additional inappropriate bias to the calculation of MACT floors and should be revised to reflect technically correct rounding procedures and the requirements of the statute. In the calculation of the MACT floor, such as the application of calculated UPLs, the EPA "rounded" the interim values and in each such instance rounded the values up. In most engineering calculations, rounding protocols provide for rounding down as well as up. Rounding ordinarily includes truncating the number of significant digits that are employed in a calculation and occurs at the end of the calculation process. The EPA justifies its decision to only round up by asserting that to do otherwise would deprive sources of the "variability" cushion they were otherwise entitled to. Again, this argument ignores the public interest in reducing emissions of HAP, as well as normal engineering protocols. It would also seem to be contrary to written EPA policy concerning rounding for NSPS compliance purposes.[36] This policy, which has not been revised to our knowledge, adopts American Society for Testing and Materials (ASTM) standard rounding protocols  -  carry at least five significant digits throughout all intermediate calculations and employ ASTM Procedure E 380 (round down if less than 5; round up if greater than 5) for the final calculation. Where a MACT floor would otherwise be calculated at 2.27, it would seem that "rounding" a final standard to 3.00 would be technically unjustifiable and would not comply with the requirement of §112 that the MACT standard be not less stringent than the average of the top 12%.
[36] See, "Memorandum: Performance Test Calculation Guidelines", William Laxton, OAQPS, and John Seitz, OAQPS.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 45
Comment: NACAA believes that the EPA's proposal to establish emission limits to two significant digits is a step in the right direction, but recommends that those limits be set to three significant digits. No reason has been advanced by the EPA for not doing so.
Response: See the response to EPA-HQ-OAR-2006-0790-2455-A1, excerpt 10.
Commenter Name: S. William Becker
Commenter Affiliation: National Association of Clean Air Agencies (NACAA)
Document Control Number: EPA-HQ-OAR-2006-0790-2455-A1
Comment Excerpt Number: 34
Comment: MACT Limits for Similar Units Should be Consistent
New and modified sources subject to §165 of the CAA must install BACT for a number of criteria pollutants regulated under the CAA, including, as relevant here, CO, SO2, NOx and Hg. In the proposed rules the EPA is setting limits for certain pollutants based on the application of "the maximum achievable control technology." There is nothing in the plain text of the CAA or its legislative history that suggests that Congress intended MACT, which applies to emissions of highly toxic and carcinogenic pollutants, to be less stringent than BACT, which applies to criteria pollutants. Indeed, for new sources it is clear that Congress intended MACT[39] to be at least as stringent as LAER, which is generally recognized as being more stringent than BACT.
Regulatory authorities are to consider costs when establishing both BACT and MACT limitations that are more stringent than the MACT floor. There is nothing in the CAA that speaks to how the EPA and permitting authorities must weigh costs against other considerations in establishing BACT. However, there has been a substantial body of precedent that speaks to this issue. In contrast, in establishing a requirement for a MACT floor, Congress effectively set a floor on what should be considered reasonable costs for MACT control technologies. Since MACT may be no less stringent than the performance level of the best-performing 12%, the costs to those sources of achieving that level of performance (including the worst-performing unit within a subcategory) must be within what was considered to be appropriate for MACT sources in that subcategory. This is of particular relevance to the set of rules under consideration, where the cost of control for similarly situated units is essentially the same but the calculated MACT floors are substantially different.
In its MACT determinations the EPA needs to explain how an emission limit imposed for a unit subject to §129 (and therefore presumably meeting the reasonable cost test for MACT) is not reasonable for an identical unit subject to §112.