Comment #6: Commenters (0192, 0194) supported the EPA's clarification that multiple new SAPUs are allowed under the rule. Commenter 0194 stated that creating a separate new SAPU greatly simplifies compliance and emissions sampling where multiple affected sources are controlled by a single lime-injected baghouse. Commenter 0192 agreed that grouping furnaces logically, based on their use, can make compliance calculations more straightforward. The commenter proposed that this concept should be extended to existing source SAPUs.
Response: The EPA acknowledges the commenters' support for the revision providing for multiple new SAPUs, but we did not propose and are not finalizing a revision to allow multiple existing SAPUs, because it is only necessary to have one existing SAPU.
Comment #7: In a comment on the supplemental proposal, commenter 0295 stated that they have concerns with the requirements found is sections 63.1510(d)(2)(ii)(D) and 63.1510(d)(2)(iii)(B) regarding the maintenance of readings `at or above 90 percent' of the pressure differential or fan RPMs in order to utilize the listed alternatives to annual flow rate measurements. The commenter stated that the 90 percent criteria are too restrictive to be of any practical benefit in the rule. This level of consistency is not routinely demonstrable for pressure differential and fan RPMs, especially for those involving an emission control device. The inherent repeatability of the measurement method itself already introduces variability of plus or minus ten percent when accounting for the repeatability of the test methods and equipment. In addition, hood static pressure can vary depending on the amount of dust loading on a fabric filter and the stage of cleaning associated with that filter, even when systems are operating normally. To account for this measurement and inherent system variability, the commenter believes that the regulatory requirement should be 80 percent of the indicator values.
In a comment on the supplemental proposal, commenter 0286 stated that, regarding the proposed alternatives (ventilation duct differential pressure or the fan revolutions per minute) to the use of Methods 1 and 2 for annual monitoring of capture/collection and closed vent systems (63.1510(d)(2)), the proposed requirement to maintain the measured parameter at or above 90 percent of the value measured during the most recent Method 2 test, is too restrictive to be of any practical benefit. The commenter stated that, presumably, if the alternative parameter is below 90 percent of the indicator value for any day of the year, the facility would be required to revert to measuring the air flow rate during that year to demonstrate compliance with the rule. The commenter stated that while this level of consistency may be representative for other types of parameters (e.g., oxygen content consistency in flue gases), it is not routinely demonstrable for pressure differential and fan RPMs, especially those involving an emission control device. The commenter stated that the inherent repeatability of the measurement method itself introduces variability of plus or minus 10 percent when accounting for the repeatability of the test methods and equipment; in addition, hood static pressure can vary depending on the amount of dust loading on a fabric filter and the stage of cleaning associated with that filter, even when systems are operating normally. The commenter stated that the allowable variability should be on the order of 80 percent of the indicator values to account for this measurement and inherent system variability.
Response: Where the EPA establishes a parametric operating limit to provide assurance of compliance associated with the performance of an operating parameter during a performance test, we rely on the capability of the facility to operate their equipment and emissions control devices, including those associated with parametric monitors, at the same level of operation as observed during the performance test. The parametric monitor must be a device capable of providing compliance assurance between emissions test events and capable of demonstrating when a distinct change in operation of the source or emissions controls has occurred. In the 2014 proposal, we proposed the daily monitoring of fan rpm as an alternative to the annual flow rate measurements. As a result of comments and the EPA's consideration of the comments, this rule provides alternatives to the requirement to conduct annual flow rate measurements of capture/collection and closed vent systems; all but one requires a parameter to be recorded daily and maintained at no less than 90 percent of the average value recorded during the most recent Method 1 and 2 performance test. Alternative monitoring parameters include differential pressure; fan RPM or fan motor amperage; static pressure measurements; duct centerline velocity using a hotwire anemometer, ultrasonic flow meter, cross-duct pressure differential sensor, venturi pressure differential monitoring or orifice plate equipped with an associated thermocouple. These monitoring alternatives rely on information from the parametric gauge reading as an indicator that a compliant volumetric flow rate is being achieved during the period between performance tests, which under these alternatives is extended to every five years. Variability in emissions test results is widely held to be +/- 15 percent, whereas parametric monitoring devices such as thermocouples can be calibrated to +/- 2 percent, pressure sensing devices to +/- 1%, amp meters to +/- 2 percent accuracy. Facilities should choose instrumentation that is capable of providing repeatable and accurate readings for their parametric monitoring records. Annual calibration of such devices is recommended, but not required by the rule. Furthermore, parametric monitors track trends that are generally not associated with process or other operational fluctuations, for instance an increase in production rate does not have a 1:1 relationship with an increase or decrease in fan motor amperage. So with parametric monitoring requirements, 90 percent (also described as a 10 percent deviation from the emissions test average) of the emissions test parametric reading average is selected as the trigger point for corrective action because it describes a control decision point; one where the monitoring data show that a process or control change has occurred. Where facilities are concerned that their parametric monitors may not provide this level monitoring assurance they would be well served to research the precision of the devices they currently have installed or plan to install and consider having their device(s) calibrated or choose one of the other compliance alternatives such as an annual direct flow rate measurement that does not rely on daily parametric monitoring measurement. With these devices calibrated or otherwise functioning normally the EPA believes that monitoring and maintaining a 90 percent operating requirement such as those in the monitoring alternatives provided in the rule is achievable for all facilities that are tracking their process rates regularly. In addition, neither commenter provided any data to support their arguments that a 90 percent level is inappropriate or that 80 percent is more appropriate.
Comment #8: In a comment on the supplemental proposal, commenter 0286 stated that the provisions for permanent total enclosures (63.1510(d)(2)(iv) acknowledges the potentially wide array of explanations for a measured parameter being outside an identified range by including a provision to investigate and restore systems when such a parameter is measured on occasion. The commenter stated that given the variability associated with ventilation systems and the requirement for daily parameter readings, a similar provision should be included for dealing with occasional static pressure and RPM measurements that are outside the applicable indicator value range and recommends that an provision such as follows be added to section 63.1510 (d)(2)(ii) and (iii):
      "When there are daily readings below 90 percent of the differential pressure (alternatively, RPM) measured during the most recent Method 2 performance test series, the facility may investigate and take steps to restore normal operation, in lieu of performing an annual flow rate measurement, provided that the reasons for the low reading are recorded."
Response: The EPA disagrees with the suggested revisions provided by the commenter. For parametric monitoring that is used by the source, instead of annual flow rate measurements, to assure continuous compliance with emission standards in the rule, corrective action must be taken to maintain monitoring parameters at or better than their performance testing baseline. Where a parameter deviates more than ten percent from this mark as an average value the EPA recognizes that the operation of the control responsible for the parameter being monitored has changed significantly and that the owner or operator must make the necessary repairs or adjustments to restore normal operations.
Comment #9: In a comment on the supplemental proposal, commenter 0294 stated that the EPA's proposal to incorporate permanent total enclosures (PTE) and the alternative inspection requirements for PTE are practical in the context of the affected sources within the secondary aluminum source category.
Response: The EPA acknowledges the commenter's support of the proposed rule language and the use of PTE in this respect.
Comment #10: The commenter (0197) stated that the EPA included thermal chip dryers in the lime injection monitoring requirements. The commenter believed that the inclusion of thermal chip dryers in proposed section 63.1510(a)(8) appears to be inadvertent because lime-injected fabric filters are not used as a control device for thermal chip dryers. If the addition of this requirement was not inadvertent, the commenter noted that it is inappropriate because the EPA did not provide notice, nor did it provide an explanation of why thermal chip dryer emissions should be controlled by a lime-injected fabric filter. The commenter recommended that thermal chip dryers should be removed from section 63.1510(a)(8).
Response: Lime injected fabric filters are not required for control of emissions from thermal chip dryers under the existing rule or the final amendments. However, if a lime injected fabric filter is used at the discretion of the owner or operator during the performance test, then it must continue to be used and the lime injection rate established during the performance test must be maintained.
3.1 	Testing Uncontrolled Group 1 Furnaces
Comment #1: In a comment on the supplemental proposal, commenter 0290 stated that as a part of the procedures to minimize untested fugitive emissions, the EPA should allow facilities to develop testing procedures on a case-by-case basis to demonstrate that the 67 percent capture efficiency assumption is not appropriate. The commenter stated that such a testing procedure might apply in particular to D/F emissions that are produced as a result of organic substances introduced with purchased scrap. According to the commenter, in a batch process those organic substances and their decomposition products have been emitted by the time the furnace charge has achieved a molten state and in some processes, the furnace remains completely closed up during the melting phase of the process and essentially 100 percent of emissions go up the stack. The commenter stated that a sequence of simultaneous stack tests with different durations could demonstrate that all D/F evolution occurs before the furnace is opened to perform necessary refining operations.
Response: It is possible that significant D/F evolution may occur when other-than-clean charge is initially placed in the furnace, while the furnace doors are open. If this is indeed the case, D/F capture might actually be lower than for pollutants like HCl. This possibility is supported by testing conducted at Southwire on September 5, 2007 (see table). In that testing, only 42 percent of the total D/F measured was in the furnace stack; this value was actually lower than the average of 71 percent for all pollutants and all tests (and on which the proposed 67 percent capture assumption was based). If D/F is emitted when the furnace doors are open, and escapes through open furnace doors, there would not necessarily be a relationship between the D/F capture efficiency and the amount of D/F generated during various times in the cycle. Therefore, it is not appropriate to measure the D/F emitted at various times during the cycle and attempt to estimate a capture efficiency based on those data. Therefore, the EPA believes that it is not appropriate to measure D/F in a sequence of simultaneous stack tests with different durations to infer a particular D/F capture efficiency, and such testing procedures are not allowed in the final rule.
Southwire Test Results Summary
Test Report Date
Pollutant
Three-run Average
Fraction in Furnace Stack
Three-run Average
Fraction in Canopy Hood Stack
June 26, 2007
PM
0.78
0.22
June 26, 2007
HCl
0.81
0.19
June 26, 2007
D/F
0.97
0.03
Sept. 5, 2007
PM
0.49
0.51
Sept. 5, 2007
HCl
0.77
0.23
Sept. 5, 2007
D/F
0.42
0.58
Average for all
All
0.71
0.29

However, it would be possible to estimate capture efficiency on a case-by-case basis by, for example, using the building as an enclosure, and measuring D/F emissions from powered roof vents. Such case-by-case demonstrations would need to be approved by the appropriate authority. Additionally, in light of comments, we have re-examined the Southwire testing data on which the proposed 67-percent capture efficiency assumption was based, and have revised the assumed capture efficiency to 80 percent.
3.2 	Worst Case Scenario Testing
Comment #1: In a comment on the 2012 proposal, one commenter (0199) asked that the EPA address and clarify in §63.1511 that stack testing is to be conducted when charging the worst-case material likely to be processed in the affected source. The commenter explained that this may mean multiple tests of separate charge material consisting of dross and separate charge material with high oil or other organic material, and for some sources, this will mean testing of a worst-case blend of these materials. The commenter suggested that the EPA provide clarification that the desired results from these tests are in fact "worst -case emissions expected under normal operations," and that this is not representative performance, as the new language implies.
The commenter also recommended that the EPA clarify that these worst case charge materials, and blends of these, have differing process rates and, therefore, the charge rate from the stack tests is not representative of the production rate that will be achieved during normal operations.
The commenter requested that until the EPA addresses these additional critical issues, the EPA acknowledge and confirm that the agreed-upon stack testing protocols from the Consent Decree are not impacted by this rule making and remain fully acceptable.
In comments on the 2012 proposal, commenters (0192, 0193, 0194) stated that in regard to changes proposed for the performance test language in paragraph §63.1511(b)(1), requirements to conduct a performance test at "the highest production rate" and "with the scrap containing the highest level of contamination" are mutually exclusive and such a requirement would not be workable. The commenters noted that the highest furnace production rates or throughputs are obtained when processing large uniform pieces of aluminum. The commenters observed that scrap with this sort of geometry (small surface area to weight ratio) contains less "contaminants" such as oil, paint or other materials per furnace charge than a scrap consisting of many small pieces, while production rates or throughput are lower when processing smaller, non-uniform scrap because of a lower density which takes up more space in the furnace.
Commenter 0197 recommended that performance tests for thermal chip dryers should be conducted under representative operating conditions. The commenter recommended that the EPA should clarify this point in the final rule by revising Proposed section 63.1511(b)(1) to state that chips should contain representative levels of contamination expected to be seen under typical unit operating conditions.
Commenters 0193, 0194 expressed concern that the EPA's revision to §63.1511(b)(1) could lead to the need for two or more performance tests on each furnace to cover multiple rates of production, even though worst case emissions can clearly be represented by a single test condition under the current regulatory requirement in §63.1511(b)(1), and could double compliance testing costs for companies without good cause. The commenters requested that either the EPA delete the change to section §63.1511(b)(1) or describe why this is change is necessary and provide an opportunity for the aluminum industry to comment on the EPA's rationale.
In a comment on the supplemental proposal, commenter 0295 stated that while they concur with the changes that the EPA has made in the testing condition requirements as found in section 63.1511(b)(1) versus what was included in the 2012 proposal, it appears that the parenthetical inclusion of the word "normal" in the first sentence is un-necessary and potentially confusing. The commenter stated that it is not clear what "normal' means in the context of testing conditions expected to produce the highest level of HAP emissions. According to the commenter, historically, facilities have been known to establish an upper limit of what emissions might be by testing under conditions that are outside "normal" operations; for example, a facility that normally melts 30 to 40 percent purchased scrap in a group 1 uncontrolled furnace might test at 100 percent purchased scrap to set an upper bound of potential emissions. The commenter stated that a facility might accumulate purchased scrap of lower than average acceptable quality in order to make up a test with dirtier than usual charge materials. The commenter stated that test results from these activities are legitimate if the emission limits are met, even though the charge is outside the "normal" range. The commenter recommended that the EPA remove the parenthetical "normal" from the text in section 63.1511(b)(1).
In a comment on the supplemental proposal regarding the EPA's modification to section 63.1512 to include a requirement for performance tests to be conducted "under representative (normal) conditions," commenter 0290 stated that it is not clear what this means in the context of worst-case testing. The commenter stated that in the past, facilities have established an upper limit of what emissions might be by testing under conditions that are outside routine operations. The commenter stated that test results are valid if the emission limit is met, even though the charge is outside the "normal" range; facilities have routinely used these and other means to achieve "worst case" conditions for a test. The commenter recommended that the EPA should remove the parenthetical "(normal)" and clarify that testing outside of the routine range of operations is allowed as long as it is representative of worst case.
Response: In the 2012 proposal, we proposed amendments to clarify that performance tests under multiple scenarios may be required in order to reflect the emissions ranges for each pollutant regulated under Subpart RRR. We received comments on the 2012 proposal that the worst case charge materials, and blends of these, have differing process rates and, therefore, the charge rate from the stack tests is not representative of the charge rate that will be achieved during normal operations. Based on the comments received on the 2012 proposal and recognizing that it may be necessary to conduct performance tests under one or multiple scenarios to be representative of the range of normal operating conditions, in the 2014 supplemental proposal we proposed revised language in 40 CFR 63.1511(b)(1) to clarify the conditions under which subpart RRR performance tests must be conducted. The intention in the subpart RRR rule is to require testing under ``worst case'' conditions from the standpoint of emissions and to establish parameters based on such testing that ensure compliance under all operating conditions. For example, in a response to comments on the original proposed subpart RRR rule regarding the inlet temperature requirement for fabric filters, the EPA stated that testing under worst case conditions, such as higher than normal fabric filter inlet temperatures, could provide a larger temperature operating range, which would be used to monitor and ensure continuous compliance between periodic performance tests (65 FR 15699, March 23, 2000). In the EPA response-to-comments document (Summary of Public Comments and Responses on Secondary Aluminum NESHAP, December 14, 1999, Docket No. A - 92 - 61, item V - C - 1, comment 4.1.47), the EPA explained that requiring multiple tests over a range of different furnace operating conditions will show that the selected monitoring parameters are valid indicators of emissions and that it may not be possible for a single test to be representative of worst case conditions and that more than a single test may be required. It is not permissible, for example, to demonstrate compliance while processing relatively uncontaminated scrap, and then at a later time, when the supply of this scrap is constrained, process more heavily contaminated scrap, without demonstrating compliance under these changed conditions based on previous emissions testing or on new emissions testing if previous tests would not be representative of the emissions from the processing of the more heavily contaminated scrap.
To clarify the requirements for testing, we proposed in the 2014 supplemental proposal that performance tests be conducted under representative (normal) conditions expected to produce the highest level of HAP emissions expressed in the units of the emission standards for the HAP (considering the extent of scrap contamination, reactive flux addition rate and feed/charge rate). If a single test condition is not expected to produce the highest level of emissions for all HAP, testing under two or more sets of conditions may be required, e.g., high contamination (or high reactive flux rate) at low feed/charge rate and low contamination (or low reactive flux rate) at high feed/charge rate. Other operating conditions may also affect the worst case test for one or more regulated HAPs. Any subsequent performance tests for the purposes of establishing new or revised parametric limits are allowed upon pre-approval from the permitting authority for major sources or the Administrator for area sources. These new parametric settings are used to demonstrate compliance for the period being tested. We solicited comment on whether the proposed amendment adequately addresses and clarifies the requirement that multiple tests may be necessary to represent different operational conditions.
After considering the comments summarized above, we are adopting the rule amendment as proposed in the 2014 supplemental proposal, with the following exception. We agree with the commenter's contention that the parenthetical "normal" could lead to confusion and differing interpretations of the requirements for testing under conditions expected to produce the highest level of HAP (considering the extent of scrap contamination, reactive flux addition rate, and feed/charge rate), i.e., "worst case" emissions. The final rule does not contain the parenthetical "normal."
Comment #2: One commenter (0199) recommended that the EPA should clarify that because stack tests are designed to measure worst-case emissions, that when determining area source status, the emission factor determined during the stack test should be multiplied times the actual measured production rate achieved when the worst case material was processed during the stack test in the calculation of potential emissions. The commenter explained that if this is not done and the emission factor determined from a stack test performed when worst case materials are processed is combined with the highest production rate achieved processing the easiest material, the projected level of emissions will be much higher than is possible and area sources may unfairly be made major sources.
Response: Area source status is generally determined by the potential-to-emit of the source (see definitions of area source and major source in 40 CFR 63.2). If the permitted annual production cannot be achieved while processing the highest-emitting type of material, then this may be taken into account in conducting an area source determination. In some cases, the capacity to process a greater throughput of a lower-emitting (on a per-unit-production basis) material may result in a higher potential-to-emit. Absent an enforceable provision limiting emissions (for example, a limitation of the annual usage of reactive flux, or annual operating hours) or a physical limitation affecting potential to emit, potential-to emit determinations are based on the allowable emission rate.
Comment #3: One commenter (0192) on the 2012 proposal agreed with the new language the EPA is proposing for 40 CFR §63.1511(b)(1), stating that the language in the rule is appropriately broad so that testing of new flux materials, increasing the allowed furnace capacity, baghouse operating parameters and other operating parameters of the furnace could also be included. The commenter recommended that the EPA should clarify in the preamble to the final rule that other parameters can be changed during a performance test.
Response: Based on the comments received on the 2012 proposal and recognizing that it may be necessary to conduct performance tests under one or multiple scenarios to be representative of the range of normal operating conditions, we proposed revised language in 40 CFR 63.1511(b)(1) in the 2014 supplemental proposal to clarify the conditions under which subpart RRR performance tests must be conducted. As we explained in the 2014 supplemental proposal, the intention is to require testing under "worst case" conditions from the standpoint of emissions and to establish parameters based on such testing that ensure compliance under all operating conditions. The final rule clarifies that performance tests be conducted under representative conditions expected to produce the highest level of HAP emissions expressed in the units of the emission standards for the HAP (considering the extent of scrap contamination, reactive flux addition rate and feed/charge rate). The final rule also allows additional performance tests for the purposes of establishing new or revised parametric limits upon pre-approval from the appropriate authority.
Comment #4: The commenter (0197) indicated that the EPA does not define "highest level of contamination" for scrap used in an initial performance test, so it is unclear what is intended and the requirement should be deleted in any event. The commenter indicated that process equipment could be put at risk of fire, explosion, or equipment damage since it was not designed to handle wet or heavily oiled chips.
Commenter 0193 asked that the word "scrap" in §63.1511(b)(1) should be replaced with the words "feed/charge material" in that all aluminum containing material to be processed in a furnace may not be scrap.
Commenters 0192, 0193, 0194 suggested that the phase "while an air pollution control device is operating" should also be deleted because all furnaces do not operate with an add-on control device.
Response: In response to the concern that process equipment could be put at risk of fire, explosion, or equipment damage if required to conduct a performance test using scrap it was not designed to handle, such as wet or heavily oiled chips, the rule does not require testing while processing a material that, because of safety considerations, would never be processed in the unit.
In the final rule, we have replaced the word "scrap" with the words "feed/charge" and have deleted the phrase "while an air pollution control device is operating" as suggested.
Comment #5: In a comment on the supplemental proposal, commenter 0294 stated that the EPA's supplemental proposal addresses concerns previously articulated in their comments on the 2012 proposal that relate to operating conditions during performance testing. The commenter stated that they support the EPA's proposed revisions to the initial performance testing requirements at section 63.1511(b)(1).
Response: The EPA acknowledges the commenter's support of the rule requirements for "worst-case" emissions scenario testing. As noted elsewhere in the response to comments, the only change to section 63.1511(b)(1) after the supplemental proposal is the removal of the parenthetical "normal" from the first sentence of the paragraph (b)(1).
3.3 	Reporting
Comment #1: One commenter (0193) objected to the proposed requirement to submit performance test reports electronically, because according to the commenter, it will impose a significant added financial burden on owners and operators of secondary aluminum smelters. The commenter asserted that the requirement constitutes double reporting and confidential business information may be jeopardized. The commenter requested that the EPA remove the electronic reporting tool (ERT) language.
Response: The EPA believes that any costs of using the ERT are reasonable and not burdensome for several reasons. The electronic reporting requirement does not add any additional testing or change the timing of when test reports are due. The requirement only states that reports are to be submitted electronically. The ERT is fully functioning and has been used successfully by industry for several years. It was designed to capture all of the information which is submitted in a typical test report and was designed with input from States and the stack testing industry.
The EPA worked with State and local agencies as well as stack testing companies (who typically prepare test reports) to develop the ERT. The ERT was designed to accept data and information that is typically collected during a performance test. Some State and local agencies have begun accepting the ERT as their reporting mechanism and with experience we believe acceptance by States will increase. In some instances state and local agencies may want a hard copy of a test report. The ERT can generate a printed test report or export the report to a word processor for reformatting. This report can be submitted to the State. The EPA believes that electronic reporting is a more efficient way to collect, store, and access test data and has set up a retrieval system such that States can access files that have been submitted using the ERT. As more States adopt electronic reporting, we believe that the need for paper reports will be diminished.
The commenter is incorrect that CBI would be jeopardized as a result of electronic reporting. Facilities can submit CBI according to the EPA's CBI procedures as always. The EPA will not make CBI publicly available, except in accordance with 40 CFR Part 2. In cases where some information in a test report is CBI, that information can be submitted separately as CBI.

Comment #2: The commenter (0197) noted that the Proposed Rule includes requirements for the submittal of reports in the records section (Proposed 40 C.F.R. § 63.1517(c)). The commenter also noted that the records section requires the source to "maintain" files and records, no reporting is required (40 C.F.R. § 63.1517(a)  -  (b)) and the first sentence of proposed section 63.1517(c) contains a reference to the requirements in paragraph (b). The commenter indicated that it is not clear if paragraph (b) is in the records or reporting section. The commenter recommended that the proposed section 63.1517(c) should be moved to section 63.1516 which contains requirements for reporting, and the reference to requirements in paragraph (b) should be clarified.
Response: In the final rule, the reporting provision that was incorrectly placed in section 63.1517 is now in the records section 63.1516, which also corrects the commenter's concern with the reference to paragraph (b).
Comment #3: In a comment on the supplemental proposal, commenter 0301 stated that, rather than requiring just recordkeeping of important compliance data as the EPA proposes, the EPA should instead require electronic reporting of all key compliance data points, so that the EPA, state and local governments, and concerned community members can provide an additional check to assure compliance. The commenter stated that if a facility is creating a record, there is very little additional time needed simply to submit the record electronically, along with other reports, and the public-interest and deterrent value of doing so is substantial.
Response: While we agree that it would be preferable for all key compliance data be recorded and reported electronically, the EPA has not yet developed electronic reporting systems for all compliance data currently required by the EPA regulations. The EPA continues to develop these electronic reporting systems and will deploy them as they are ready.
3.5	Other

Comment #1: One commenter (0194) agreed with the EPA's clarification for the daily SAPU emission limit calculation. The commenter noted that the commenter's locations have actually followed the proposed approach since the NESHAP became effective in 2003.

Response: The EPA acknowledges the commenter's support.
Comment #2: In a comment on the supplemental proposal, commenter 0301 stated that they support the EPA's proposal for annual inspection and improvements to compliance requirements.

Response: The EPA acknowledges the commenter's support of the rule requirements that clarify inspection and compliance requirements.
4. Compliance Dates

Comment #1: In a comment on the supplemental proposal, commenter 0296 stated that the compliance schedule in the supplemental proposal is much more reasonable than the compliance schedule in the 2012 proposal, allowing facilities an adequate window of opportunity for any new technology additions to be researched, selected, purchase, financed and installed; it is also consistent with the 2 year compliance schedule in subpart ZZZZZZ.
Response: The EPA acknowledges the commenter's support of the compliance dates.

5. Startup, Shutdown, and Malfunction
5.1 	Removal of SSM Exemption
Comment #1: One commenter (0195) stated that the EPA does not have the authority to amend existing MACT standards to make them more stringent, as is being done by proposing the new SSM standards. The commenter argued that the EPA's authority under CAA section 112(d)(6) is to "review and revise as necessary (taking into account developments in practices, processes, and control technologies), emissions standards promulgated under this section no less often than every 8 years." The commenter observed that the EPA did not invoke its section 112(d)(6) authority to support the Proposed SSM Provisions, but even if it had, section 112(d)(6) does not provide broad authority to reconsider aspects of previously issued MACT standards unrelated to "developments in practices, processes, and control technologies." The commenter maintains that the EPA cannot simply revisit and redo a MACT determination long after it has been issued, as the EPA attempts to do with the Proposed SSM Provisions. The commenter argued that the EPA cannot change its mind about what standards are required to comply with CAA sections 112(d)(2) and (3), nor can it recalculate a MACT floor based on subsequent performance.
The commenter asserted that reassessing existing NESHAP that were based on the MACT floor and imposing more-stringent requirements, would be inconsistent not only with the statute's careful provision of technology-review and residual-risk authority to follow establishment of MACT standards, but also with Congress' desire for finality evident in the judicial review of provisions of CAA section 307(b), which allows challenges to MACT standards within 60 days of promulgation.
The commenter stated the EPA would have to justify why the decisions reflected in the current standards are wrong and why the new standards meet the required criteria that the EPA must satisfy in issuing MACT standards under CAA sections 112(d)(2) and (3).
The commenter argued against the EPA's interpretation of Sierra Club v. EPA, stating that the Sierra Club decision interpreted the NESHAPs General Provisions, not what the EPA may or may not include in source-category-specific MACT standards.
The commenter stated that although the D.C. Circuit and the EPA referred to the provision vacated in the Sierra Club decision as an "exemption" from hazardous air pollutant standards during SSM events, other portions of the NESHAP General Provisions impose various requirements that apply to sources both during SSM events (including the obligation to minimize excess emissions) and in anticipation of and following SSM events (including requirements to prepare a plan to address SSM events and to report SSM events).
The commenter pointed out that opinions where the court was looking at source-category specific MACT standards have emphasized the need for those standards to recognize and accommodate higher emission levels that occur at times other than normal operations. See, e.g., Sierra Club v. EPA, 167 F.3d 658, 665 (D.C. Cir. 1999).
The commenter asserted that the Sierra Club decision did not say that the same emission limitations that the EPA has derived for normal operations must also apply during SSM events. The commenter claimed that although an open-ended exemption from any standard under section 112 is inconsistent with the Sierra Club holding that, for section 112 MACT standards, "there must be continuous section 112-compliant standards", Sierra Club does not preclude the EPA from applying different standards during SSM events than apply during normal operations. The commenter argued that the opinion acknowledges that section 302(k)'s "inclusion of [the] broad phrase" "any requirement relating to the operation or maintenance of a source to assure continuous emission reduction" in the definition of "emission standard" suggests that the EPA can establish MACT standards consistent with CAA section 112 "without necessarily continuously applying a single standard."
The commenter stated that there is ample precedent for the EPA applying a different standard during SSM events. The commenter noted that language the D.C. Circuit considered dispositive in interpreting the EPA's standard-setting authority under section 112  --  the statement in the CAA section 302 definition of "emission limitation" and "emission standard" that it "limits the quantity, rate, or concentration of emissions of air pollutants on a continuous basis"  --  has been in the statute since 1977. The commenter observed that throughout that time, the EPA has not required sources to meet NSPS emission limitations under CAA section 111 established for normal operations during SSM events.
The commenter noted that Congress enacted the "continuous basis" language in section 302(k) knowing that the EPA's emissions standards under section 111 exempted SSM periods. The commenter argued that the "continuous basis" language inserted in 1977 is related to whether sources should be allowed to use temporary or intermittent pollution control technologies which entailed temporary reductions in emissions when weather conditions were poor, not what emission limitations apply during SSM periods, nor the EPA's established practice of exempting excess emissions during SSM events from the performance standards applicable to normal operations. The commenter noted that the legislative history indicates Congress was aware that alternative emission limitations might at times be necessary, even though the emission limitations were established based on the capability of "continuous controls" like scrubbers. See, e.g., S. Rep. No. 94-717 at 78 ("It is recognized that the source controls may not be available to achieve the full reduction required of a particular source under particular circumstances. In such case, supplementary programs can and should be developed. But this flexibility occurs only after imposition of the continuous emission limitation.").
The commenter asserted that the Sierra Club decision did not address whether the EPA could use a "design, equipment, work practice or operational standard," as authorized under CAA section 112(h) and included in the definition of "emission limitation" and "emission standard" in CAA section 302(k), in lieu of a numerical emission limitation during SSM events. The commenter stated that the EPA told the Court that the General Provisions SSM exemption struck down in Sierra Club was not an alternative standard based on the work practice standard authority. The commenter noted that the EPA argued in that case that section 112(h) was irrelevant to its authority to exempt excess emissions during SSM events.
 The commenter maintained that the EPA cannot use the Sierra Club decision as a justification for ignoring an inability of even the "best performers" to achieve during SSM events the emission limitations the EPA has established for normal operations. The commenter asserted that the approach the EPA is proposing would not establish "continuous section 112-compliant standards" that the Sierra Club decision concluded are required, as MACT emission standards must be "achievable." The commenter stated that an emission limitation that applies during SSM events does not meet the requirement of CAA section 112(d)(2) that "emission standards" under that section be "achievable" if in fact the EPA has not demonstrated that the limitation is "achievable" with available technology. The commenter argued that an emission limitation that applies during SSM events has not been demonstrated to be "achieved" by the best-performing 12% of units in the category under CAA section 112(d)(3) unless the EPA can show that those best performers actually meet that emission limitation during SSM events. The commenter asserted that the EPA has not demonstrated that the emission limitations in the existing MACT standards, if they also applied during SSM events, would comply with section 112 when applied to SSM periods.
The commenter argued that the courts have long recognized that a "technology based standard discards its fundamental premise when it ignores the limits inherent in technology." NRDC v. EPA, 859 F.2d 156, 208 (D.C. Cir. 1988). The commenter provided examples. The D.C. Circuit recognized, in Portland Cement Ass'n v. Ruckelshaus, 486 F.2d 375, 398 (D.C. Cir. 1973), a decision reviewing standards under CAA section 111, that "`start-up' and `upset' conditions due to plant or emission device malfunction, is an inescapable aspect of industrial life and that allowance must be made for such factors in the standards that are promulgated." In Essex Chem. Corp. v. Ruckelshaus, 486 F.2d 427, 432 (D.C. Cir. 1973), another section 111 case, the court held that SSM provisions are "necessary to preserve the reasonableness of the standards as a whole." In National Lime Ass'n v. EPA, 627 F.2d 416 (D.C. Cir. 1980), another case reviewing emission standards promulgated under CAA section 111, the court held that the CAA requirement that NSPS be "achievable" means that the standards must be capable of being met "on a regular basis," including "under most adverse circumstances which can reasonably be expected to recur," including during periods of SSM.
The commenter cited cases in support of the commenter's argument related to the Clean Water Act.
The commenter stated that Weyerhaeuser Co. v. Costle, 590 F. 2d 1011 (D.C. Cir. 1978), does not support the EPA's position. The commenter asserted that in that case, the court was discussing a "technology forcing" standard, rather than one, like MACT, that is to be based on what is already being "achieved" or has been demonstrated to be achievable. The commenter claimed that the SSM events that the EPA acknowledges are expected to occur at sources subject to the Proposed Standards are a far cry from the unusual "'uncontrollable acts of third parties,' such as strikes, sabotage, operator intoxication, or insanity" that the court was considering in the passage quoted by the EPA. The commenter stated that industry is not requesting that the MACT standards provide relief from numerical emission limitations during those unusual types of events. The commenter emphasized that the Weyerhaeuser decision came long before NRDC v. EPA, 859 F.2d 156 (D.C. Cir. 1988) which, as noted above, affirmed the need for an upset provision to address circumstances where compliance with effluent limitations is impossible through no fault of the permittee, and which endorsed Marathon Oil.
The commenter noted that the EPA acknowledges this precedent in the rule preamble, but suggests that "intervening case law such as Sierra Club v. EPA and the CAA 1977 amendments undermine the relevance of these cases today." However, the commenter maintained that the EPA does not explain why it believes that to be the case. According to the commenter, Sierra Club v. EPA did not address this precedent, and the 1977 CAA amendments if anything support the conclusion that emission standards need to deal with the inability of a source to meet the normal emission limitations during particular circumstances. The commenter argued that the National Lime Ass'n decision, which relies in part on the cases the EPA referenced in the preamble, and which directly addresses the need for emission limitations that address reasonably anticipated adverse circumstances, post-dates the Clean Air Act Amendments of 1977 by three years.
The commenter pointed out that the Sierra Club decision rejected the EPA's asserted discretion to not to impose any emission standard covering SSM periods. The commenter asserted that the Sierra Club decision expressly recognized that different standards, including non-numerical standards, may (and in some cases must) apply during non-standard operating conditions, such as SSM events. The commenter added that the statement in the majority opinion that "Congress gave no indication that it intended the application of MACT standards to vary based on different time periods" is contradicted by other statements in the opinion that a MACT standard need not continuously apply a single emission limitation, is dicta because that was not the situation presented by the challenged regulations and argued by the EPA, ignores the extensive case law about technology-based limitations referenced above, and does not in any event say that the CAA precludes the EPA from adopting different emission limitations that apply during SSM events.
One commenter (0195) disputed EPA's approach to malfunctions is consistent with CAA section 112 and is a reasonable interpretation of the statute. The commenter observed that the EPA says it "has determined that CAA section 112 does not require that emissions that occur during periods of malfunction be factored into development of CAA section 112 standards," which the commenter maintains the EPA makes little effort to justify. The commenter disagreed with the EPA's statement that "[t]here is nothing in CAA section 112 that directs the agency to consider malfunctions in determining the level `achieved' by the best performing or best controlled sources when setting emission standards," claiming that there is nothing in CAA section 112 that allows EPA to ignore malfunctions and set MACT standards based on a level of emissions that even best-performing sources only achieve part of the time. The commenter asserted that EPA's rationale for not factoring in malfunctions directly contravenes congressional intent that MACT floor standards be based on what the best sources actually achieve.
The commenter recommended that the EPA to use authority under CAA section 112(h) to prescribe alternative design, equipment, work practice or operational standards where it is not feasible to set or enforce a numerical emission limit. The commenter disagreed with EPA's view that applying the concept of "best performing" is inconsistent with a source experiencing a malfunction. The commenter asserted that there are work practices  -  such as monitoring of operating parameters to identify a malfunction and stopping or cutting back the process accordingly  -  that represent the best practices for minimizing emissions during a malfunction, and these best practices represent the "the maximum degree of reduction in emissions of the hazardous air pollutants...achievable...through application of measures, processes, methods, systems or techniques" and reflect "the emission control that is achieved in practice by the best controlled similar source[s]".
One commenter (0195) asserted that the EPA's historical definition of "malfunction" is not in any way binding on how EPA defines the events that the Agency will refuse to take into consideration when establishing MACT emission standards. The commenter stated that by acting as if it were binding on EPA standard-setting, EPA has proposed a perverse approach to establishing emission standards in which the more common a situation is that results in higher emissions than normal operations, the less likely it is that EPA will write emissions standards to take that situation into account -- either in the standards themselves or in the affirmative defense.
One commenter (0195) stated that the elimination of SSM provisions in the existing MACT standards would put operators in a Catch-22 situation: the NESHAP would no longer accommodate the excess emissions that EPA knows will occur regularly during normal plant operations, due to process variability and control equipment operations and availability, yet those same events would appear to be ineligible for the "affirmative defense" that EPA proposes as a means of addressing excess emissions that occur despite a source's proper design and operation, because the "affirmative defense" is only available for excess emissions that result from "infrequent" events that cannot be "foreseen...and planned for." The commenter asserted that for the EPA to finalize these proposed actions would be unreasonable, arbitrary and capricious, and not in any way required by the Clean Air Act or judicial precedent.
One commenter (0195) stated that EPA ignores the undisputed existence of malfunctions even at best-performing sources, and the EPA claims falsely that the best-performing sources "achieve" emission levels that they undisputedly do not achieve part of the time. The commenter disagreed with the EPA's conclusion that malfunction events are not representative of best-performing sources. See, e.g., Cement Kiln Recycling Coalition v. EPA, 255 F.3d 855, 862-865 (D.C.Cir.2001) (recognizing that there is variability in the performance of control technologies, which needs to be accounted for in establishing emission limitations based on the MACT floor); Sierra Club v. EPA, 167 F.3d 658, 665 (D.C. Cir. 1999). The commenter observed that one goal of best performing sources is to operate in such a way as to avoid malfunctions, but the commenter believes that that is all the more reason for the EPA to acknowledge that those sources experience malfunction events.
One commenter (0195) asserted in regard to malfunction events, that by proposing MACT standards that EPA recognizes even the best performing existing sources cannot achieve part of the time, EPA is going beyond the MACT floor, yet without making the demonstrations that the statute and case law require the Agency to make in order to impose beyond-the-floor MACT standards. The commenter claimed that the EPA has not justified as reasonable the conditions that the EPA proposes to impose on sources during malfunctions in order to be excused from civil penalties "taking into consideration the cost of achieving such emission reduction, and any non-air quality health and environmental impacts and energy requirements...."
The commenter stated that it is indefensible for EPA to acknowledge that malfunctions are inevitable, even for the best performing sources, and yet refuse to include emissions data representing malfunctions (if such data exist) in calculating the MACT floor, and then require that those MACT floor limitations be met even during malfunctions. The commenter asserted that the EPA is obligated to consider representative data reflecting emissions during malfunctions in its MACT floor calculations for steady-state operating conditions, if that data can be gathered.
The commenter recommended that to the extent EPA had access to continuous monitoring data for emission units covered by the NESHAP, EPA could have conducted analyses of emissions levels during malfunction events. The commenter noted that even if the continuous monitoring data are for parameters not regulated by the Proposed Standards, analysis of monitoring data for those other parameters during malfunction events might form a reasonable basis for EPA's assessment of what standards are achieved or achievable during malfunctions. The commenter suggested that many types of sources are required by many state agencies to submit deviation reports or malfunction reports when they experience a malfunction that causes an exceedance of an applicable limitation. The commenter observed that the EPA does not appear to have made any attempt to obtain and analyze such reports, in order to assess what type of requirement might reasonably apply to the subject emission units during malfunctions.
The commenter offered several options for setting MACT standards under CAA section 112 that would apply during malfunction events:
::	Establish an emission limitation that applies at all times, but that has an averaging time of sufficient duration that short, infrequent spikes in emissions due to malfunctions would not cause the source to exceed the emission limitation (while at the same time ensuring that the source does not operate in a way that causes frequent, lengthy excursions above the normal controlled emission rate);
::	Use the flexibility accorded by CAA section 302(k) (defining "emission limitation" and "emission standard" to include "any requirement relating to the operation or maintenance of a source to ensure continuous emission reduction, and any design, equipment, work practice or operational standard promulgated under" the CAA) to address emissions during malfunction events through operational requirements rather than by applying the same limits on pollutant concentrations in exhaust gases that apply during normal operations; and/or
::	Promulgate under CAA section 112(h) a design, equipment, work practice, or operational standard, or combination thereof, because it is not feasible to prescribe or enforce an emission standard.
The commenter stated that the EPA did not consider any of these types of options, and the lack of evaluation of these options renders the Proposed Rule arbitrary, and requires EPA to develop a new proposal.
One commenter (0193) disagreed with the EPA's proposed approach for regulating malfunctions, stating that it is unjust and creates a legal dilemma for owners/operators to be accused of exceeding unachievable emission standards due to events outside their control. One commenter (0194) expressed concern that the EPA, recognizing that malfunctions are not all reasonably preventable, creates a legal dilemma for owners/operators to be accused of exceeding unachievable emission standards due to events outside their control.
For technology-based standards, a commenter (0197) noted that EPA and courts have recognized that EPA must either (a) consider SSM in setting the standards or (b) provide an upset defense. The commenter indicated that EPA should revise its SSM provisions.
Commenter 0298 on the 2014 supplemental proposal (same as commenter 0195 on 2012 proposal) stated when EPA ignores emissions that even best-performing sources experience during malfunctions, EPA breaches its duty to set standards on the basis of real-world performance; it fails to take into account how sources actually operate and unlawfully prohibits emissions that cannot be avoided. See, e.g., Sierra Club v. EPA, 167 F.3d 658, 665 (D.C. Cir. 1999) (a best-performing source should not violate a standard supposed to be based on what it "achieve[s] in practice"); see also 76 Fed. Reg. 15628 (rejecting a comment as "inappropriate" because it "would result in emission limits that even the best performing sources would be expected to exceed"). The commenter stated that every court that has addressed the issue, both under the CAA section 111 requirement that new source performance standards be based on the best demonstrated control technology and under the similar technology-based requirements of CAA section 112(d) and (h), has indicated that EPA must take the effect of malfunctions on emissions into account when establishing such technology-based emission standards. See Portland Cement Ass'n v. Ruckelshaus, 486 F.2d 375, 398-99 (D.C. Cir. 1973); Essex Chemical Corp. v. Ruckelshaus, 486 F.2d 427, 432 (D.C. Cir. 1973); Nat'l Lime Ass'n v. EPA, 627 F. 2d 416, 431 (D.C. Cir. 1980); Cement Kiln Recycling Coalition v. EPA, 255 F.3d 855, 872 (D.C. Cir. 2001); NACWA v. EPA, 734 F.3d 1115, 1158 (D.C. Cir. 2013) The commenter stated that while EPA may be implying in the supplemental notice that the opportunity that a source would have to argue to a court in an enforcement action that a malfunction justifies a reduced or no penalty, is a satisfactory means of accommodating the effect of malfunctions on what standards are achievable with available technology, the statute directs EPA to set standards based on what the available technology can do or, in the case of MACT floor standards, based on what the best performers are actually doing. The commenter stated that nothing in the statutory language or legislative history indicates that Congress intended EPA to establish MACT standards that apply at all times, but that even best performers cannot meet during unavoidable malfunctions, and then have penalties potentially mitigated in an enforcement action. According to the commenter, courts agree with this analysis, stating repeatedly that relying on enforcement discretion is no substitute for setting technology-based standards that reflect the performance of that technology during all reasonably anticipated conditions. See, e.g., Portland Cement, 486 F.2d at 398 n.91; Nat'l Lime, 627 F. 2d at 431 n.46; Marathon Oil Co. v. EPA, 564 F.2d 1253, 1273 (9th Cir. 1977). The commenter stated that, moreover, the enforcement discretion approach does not satisfy the purpose of CAA section 112 of reducing HAP emissions; a post-hoc case-by-case evaluation of emission circumstances, as EPA intends to handle all malfunction periods, will not prevent or reduce emissions of HAPs. The commenter stated that rather than the starting point being affirmative steps to prevent emissions as Congress intended (including steps that would have been encouraged by the conditions specified in the affirmative defense), the starting point for the approach in the supplemental notice is the post-emission presumption of wrongdoing by the source operator.
Commenter 0298 stated that EPA has tools for accounting for malfunctions in the standards once the affirmative defense is eliminated. The commenter stated that the supplemental notice repeats EPA's conclusory statements in the proposed rule that it would be too difficult for EPA to consider malfunctions when establishing emission standards and that doing so would result in standards that are too lenient. According to the commenter, the court decision that EPA cites, Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), specifically acknowledged that EPA has authority under the CAA to set different standards that apply at different times, so long as some CAA section 112 compliant standard applies at all times and EPA has used that authority in numerous rulemakings to set alternative emission standards that apply during startup and shutdown periods. The commenter stated that there is nothing in EPA's mandate to set emission standards allows EPA to decline to even assess whether it has sufficient data, or can obtain sufficient data, to set numerical limitations that apply during malfunction events. The commenter stated that EPA also can use sections 112(h) and 302(k) to substitute a design, equipment, work practice, or operational standard for a numerical emission limitation; the use of work practices will in most cases be more practicable and more comprehensive than trying to establish numerical standards to address all malfunctions. The commenter stated that one approach that has proven effective in the past is to specify the elements and objectives of a plan that the source must develop, follow, and review to assure that the source is taking the appropriate steps before, during, and after a malfunction to minimize excess emissions; it is likely that most if not all or the sources identified as best performers have such plans and follow them to responsibly address malfunctions. The commenter stated that EPA has already shown that it can use work practices when a source is operating in other than normal steady-state operation, when EPA established work practice standards in lieu of numerical emission limitations for numerous source categories that apply during startup or shutdown. The commenter stated that before EPA promulgates revised emission standards for secondary aluminum plants that apply even during malfunctions but that contain no affirmative defense or other provision addressing malfunctions, EPA should determine an appropriate set of work practices, or a combination of work practices and alternative numerical emission limitations, that address higher emissions associated with malfunctions of properly designed and operated MACT technology, and EPA must offer its analysis for public comment before finalizing the deletion of the affirmative defense and the adoption of the alternative standards.
Response: The EPA disagrees in many ways with the commenters, first in that the EPA does not lack authority to make the changes proposed. We specifically disagree with the commenter's suggestion that Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008) is not relevant because it addressed the SSM exemption in the General Provisions rather than source category-specific MACT standards. The holding in Sierra Club that emissions limitations under section 112 must apply continuously and meet minimum stringency requirements, even during periods of startup, shutdown and malfunction, is clearly applicable to source category-specific MACT standards. As we explained in the 2012 and 2014 proposals, our SSM-related rule revisions are in response to the Sierra Club court's vacature of the SSM exemption in §§63.6(f)(1) and 63.6(h)(1). 77 FR at 8598-8600. When incorporated into section 112(d) regulations for specific source categories, these two provisions exempted sources from the requirement to comply with otherwise applicable MACT standards during periods of SSM. Subpart RRR, Appendix A incorporated several General Provisions related to SSM, specifically including §§63.6(f)(1) and 63.6(h)(1). The court's vacature rendered those provisions null and void prior to this rulemaking. The mandate implementing the court's decision was issued on October 16, 2009, at which time the vacated SSM provisions were clearly no longer in effect, and standards in subpart RRR applied at all times, including periods of SSM. The rule changes to remove the vacated SSM provisions from subpart RRR are ministerial actions by the EPA to reflect the vacature by the court.
In addition, in Medical Waste Institute v. EPA, 645 F. 3d 420, 425-27 (D.C. Cir. 2011), the D.C. Circuit Court held that EPA may permissibly amend improper MACT determinations, including amendments to improperly promulgated floor determinations, using its authority under section 112(d)(2)-(3). In light of the court decisions in Sierra Club and National Lime Ass'n v. EPA, 233 F.3d 625, 633-34 (D.C. Cir. 2000), the exemption from standards in Subpart RRR for HAP emitted during SSM was not proper. Similarly, the Court's decision in Portland Cement Ass'n v. EPA, 665 F.3d 177, 189 (D.C. Cir. 2011) confirms that although 112(d)(6) requires EPA to reassess its standards every eight years, nothing prohibits it from doing so more often, including revising existing floors if need be. The commenter is thus incorrect that EPA lacks authority to amend promulgated MACT standards or that section 112(d)(6) provides exclusive authority to address standards that apply during SSM.
We are not adopting different standards for periods of startup and shutdown, although we do not claim that the Sierra Club decision constrains our authority to set different standards, including work practice standards under section 112(h), for SSM periods. Instead we are applying the existing Subpart RRR MACT standards to periods of startup and shutdown because the scrap processed at secondary aluminum production facilities is the source of emissions, and we expect emissions during startup and shutdown to be no higher, and most likely significantly lower, than emissions during normal operations since no scrap is processed during startup and shutdown periods. We stated in the preamble to the 2012 proposed rule that we knew of no reason why the existing MACT standards should not apply at all times, and we have received no information to change that conclusion. For additional responses to comments concerning standards during periods of startup and shutdown and alternative methods for demonstrating compliance with production-based limits, see the discussion in section 5.2 below.
The EPA also disagrees with the commenter's suggestion that the existence of an SSM exemption in rules implementing section 111 in 1977 when Congress enacted the "continuous basis" language in the definition of "emission standard" is evidence that Congress approved of that regulatory SSM exemption. We do not believe the legislative history cited supports that Congress was aware or approved of that exemption.
The commenters assert that the EPA must account for malfunctions when determining the emissions level achieved by the best performing sources, but this view is neither reasonable nor supported by the text of the CAA. A malfunction is defined as a "sudden, infrequent, and not reasonably preventable failure of air pollution control and monitoring equipment, process equipment or a process to operate in a normal or usual manner * * *" (40 CFR 63.2). The EPA interprets CAA section 112 as not requiring emissions that occur during periods of malfunction to be factored into development of CAA section 112 standards. Under CAA section 112, emissions standards for new sources must be no less stringent than the level "achieved" by the best controlled similar source and for existing sources generally must be no less stringent than the average emission limitation "achieved" by the best performing 12 percent of sources in the category. There is nothing in section 112 that directs the Agency to consider malfunctions in determining the level "achieved" by the best performing sources when setting emission standards. As the D.C. Circuit has recognized, the phrase "average emissions limitation achieved by the best performing 12 percent of" sources "says nothing about how the performance of the best units is to be calculated." NACWA v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). In addition, accounting for malfunctions in setting emission standards would be difficult, if not impossible, and could lead to standards that are not reflective of levels achieved by a well-performing non-malfunctioning source. The EPA's approach to malfunctions is a reasonable interpretation of the statute. If a source fails to comply with the applicable CAA section 112 standards as a result of a malfunction event, as discussed above, the EPA would determine an appropriate response, and the source can raise any and all defenses in any enforcement action that may be filed.
The EPA's approach both accounts for variability associated with a reasonably foreseeable range of operating conditions and recognizes that enforcement mechanisms can address emission exceedances due to unpreventable equipment or process failures. While commenters may seek greater accommodation for malfunctions, such accommodation is not compelled by the Act.
Unlike start-up and shut-down, which are foreseeable operations, no one can predict the nature, scope, severity, timing, length, number or likely recurrences of malfunctions a source may  -  or may not  -  experience. Although the EPA bases emission standards on different manners of operations and circumstances, the EPA only takes into account conditions that are "foreseeable" and "which can reasonably be expected to recur." Sierra Club v. EPA, 167 F.3d 658, 665 (D.C. Cir. 1999); see also Nat'l Lime Ass'n v. EPA, 627 F.2d. 416, 431 n.46 (1980). Virtually no malfunction is foreseeable in terms of its nature, timing or effect on emission levels and no operator knows if or when a malfunction could recur.
The commenters identify no language in the statute that even implies that EPA must factor into MACT emission standards the emission levels that occur during malfunctions. Yet the commenters assert that CAA section 112 mandates that EPA account for malfunctions in establishing every MACT standard or set a separate MACT standard for malfunctions, so that they reflect higher emission levels that might occur during undefined, unidentified malfunction events. The commenters appear to rely on the silence of section 112, which does not speak directly to how malfunctions are to be treated to support their view, filling the void with the commenters' own judgments of how EPA must address such uncertain and undefined events.
Although EPA may have authority to address malfunctions through different mechanisms  -  albeit limited by the Court in Sierra Club v. EPA (striking down exemptions for malfunctions) and NRDC v. EPA (striking down an affirmative defense for malfunctions)  -  EPA is not required by section 112 to account for malfunction emissions by resetting MACT standards (e.g., with long averaging times) or by setting separate MACT standards (e.g., work practice standards) as suggested by the commenter.
A commenter asserts that relying on case-by-case enforcement discretion to address violations caused by malfunctions does not satisfy the purpose of CAA section 112 of reducing HAP emissions because it will not prevent or reduce emissions. We disagree. Applying the existing Subpart RRR MACT emission standards at all times meets the Act's purpose in section 112 and, as enforceable emission standards, limits HAP emissions in accordance with the Act. The commenter states that enforcement discretion is no substitute for accounting for malfunctions in the standards themselves and suggests that different standards or requirements could be applied to malfunction events. As discussed above, we are not required to account for malfunction emissions in section 112 standards, and based on the information available to EPA concerning compliance by sources with Subpart RRR standards, we find no reason to do so.
A commenter contends that section 112 mandates that EPA establish MACT standards so that they reflect higher emission levels that might occur during unidentified, unmeasured malfunction events. To support its argument, the commenter states that emission limitations must be "achieved in practice". The commenter asserts that the EPA has failed to develop standards that are "achieved in practice" if the best performing sources are expected to have malfunctions, and those malfunctions result in emissions that exceed the standard. But a source that suffers worker malfeasance or experiences a hurricane or a terrorist event may also exceed emission standards at certain times. These events, like malfunctions, do not transform achievable standards into unachievable standards. Indeed, under the commenter's reasoning, every MACT standard is potentially invalid because it does not reflect emission levels that may occur during the next malfunction, act of God, strike, malfeasance or other unpredictable event.
Hurricanes and malfeasance can occur at well-maintained and well-managed sources and can cause upset conditions that result in violations of emission standards, but this does not warrant factoring such unpredictable events into revised emission standards. Even if malfunctions were inevitable for all sources, including the best-performing sources, that does not make it possible to take them into account when establishing MACT emission standards, because they are still unknown in frequency, length, magnitude and, most importantly, effect on emission levels.
The commenter asserts that the EPA inappropriately relies on the CWA case Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) because the Weyerhaeuser court based its holding on the fact that the standards at issue there were technology-forcing. While the Court did address this point, it went on to uphold EPA's case-by-case enforcement discretion approach to addressing malfunctions because interjecting factors dependent on "murky determinations concerning the sequence of events in the plant, whether those events would have been avoidable" and similar factors, is inconsistent with the intent of Congress to require numeric emission standards that are measurable and easily enforceable. 590 F.2d at 1057-58. The commenter also argues that the Weyerhaeuser decision only addressed effects from "uncontrollable acts of third parties" which are "a far cry" from events that would occur under Subpart RRR. In fact, the Court in Weyerhaeuser was addressing "unusual events such as plant start-up and shut-down, equipment failures, human mistakes, and natural disasters." 590 F.2d at 1056.
The commenter implies that Weyerhaeuser was overruled by another Clean Water Act case, NRDC v. EPA, 859 F.2d 156 (D.C. Cir. 1988), citing it for the proposition that a technology-based standard must accommodate defects in technology. That case was decided in 1988, long before the court decisions that found an exemption and an affirmative defense for malfunctions were contrary to the requirements of the Act. Moreover, the discussion of technology-based standards in the NRDC decision was dicta. The holding in NRDC was that water quality based standards do not need to account for malfunctions despite sources' use of technology for compliance. Although Congress revised the HAPs program in 1990 to have technology serve as the core for establishing emission standards, those standards are also not strictly control technology-based but rather are based on the emission levels actually achieved in practice, which the Court has explained goes beyond what can be achieved solely through available control technology. See Sierra Club v. EPA, 479 F.3d 875, 882-83 (D.C. Cir. 2007).
The commenter also offers the decision in Cement Kiln Recycling Coalition v. EPA to support its argument that malfunctions must be considered in developing emissions standards. However, nothing in Cement Kiln even implies that EPA has a duty to reflect in its emission standards emission levels that might occur during unpredictable malfunction events. To the contrary, Cement Kiln cuts to the heart of commenters' argument. The fundamental principle of the commenters' argument is that due to malfunctions, the MACT emission standards, which have been achieved by secondary aluminum production facilities, may be "unachievable" if specific sources experience a malfunction (citing Cement Kiln Recycling Coalition v. EPA, 255 F.3d 855, 872 (D.C. Cir. 2001); Sierra Club v. EPA, 167 F.3d 658, 665 (D.C. Cir. 1999); Portland Cement Ass'n v. Ruckelshaus, 486 F.2d 375, 398-99 (D.C. Cir. 1973); Essex Chemical Corp. v. Ruckelshaus, 486 F.2d 427, 432 (D.C. Cir. 1973); Nat'l Lime Ass'n v. EPA, 627 F. 2d 416, 431 (D.C. Cir. 1980); NACWA v. EPA, 734 F.3d 1115, 1158 (D.C. Cir. 2013)). The Court in Cement Kiln, however, rejected the notion that because a MACT standard may not be achievable by some sources, it is invalid. Cement Kiln, 255 F.3d at 861 ("EPA may not deviate from section 7412(d)(3)'s requirement that floors reflect what the best performers actually achieve by claiming that floors must be achievable by all sources using MACT technology."). See also Sierra Club v. EPA, 479 F.3d at 878; NACWA, 734 F.3d at 1150 (explaining that the argument that a MACT standard is invalid because it is not achievable by all sources at all times has been "roundly rejected" by the Court)."
Comment #2: One commenter (0195) argued that the EPA's proposal to replace §63.6(e)(1) with the somewhat different "general duty" language in proposed sections 63.1506(a)(5) and 63.1520(a)(8) is not being proposed under CAA section 112(d)(6) or 112(f), and the EPA therefore lacks authority to make this change to the existing RRR NESHAP. The commenter disagreed with the EPA's statement that the proposed sections 63.1506(a)(5) and 63.1520(a)(8) replace General Provisions requirements that reference vacated SSM provisions. The commenter stated that the D.C. Circuit did not vacate the provision the EPA proposes to replace, §63.6(e)(1), in Sierra Club v. EPA (which vacated the "exemption" for SSM events in sections 63.6(f)(1) and (h)(1), not the requirement for good air pollution control practices), and, contrary to the EPA's assertion in the preamble to the Proposed Rule, §63.6(e)(1) does not reference provisions that were vacated in Sierra Club v. EPA.
The commenter maintained that even if the EPA had authority to change the existing MACT standards in ways not required to address residual risk or new technology, the Agency would have to provide a cogent explanation of why the old rule was unacceptable and the new rule is necessary, which the commenter claimed the EPA has not done.
The commenter recommended that the EPA delete proposed section 63.1506(a)(5) from the final rule, but if the EPA does not delete the proposed section, the commenter recommended that the EPA re-propose the provision with some explanation of the basis and purpose for the provision, to allow the public an opportunity to provide meaningful comments, as required by CAA section 307(d)(3).
Response: The EPA disagrees with the commenter, in that the EPA does not lack authority to make the changes proposed (see response to comment #1 above). The EPA explained in the 2012 proposal that we were proposing to add language to this regulation to replace General Provision requirements that reference vacated SSM provisions. 77 FR at 8597, 8598-8600. We are revising the general duty language because some of the language in that section is no longer necessary or appropriate in light of the elimination of the SSM exemption. Specifically, the prior language in 63.1506(a)(5) and 63.1520(a)(8) characterized what the general duty entails during periods of SSM. With the elimination of the SSM exemption, there is no need to differentiate between normal operations, startup and shutdown, and malfunction events in describing the general duty. Sources will be subject to emission standards at all times, including during periods of startup and shutdown and malfunction, and other language in the final rule already makes clear that the general duty to minimize emissions applies at all times. Therefore, there is no need to specify that malfunctions need to be corrected as soon as possible or to further specify the application of the general duty requirement during periods of SSM. Our notice of proposal was sufficient on this topic and the rule revisions do not need re-proposal.
Comment #3: One commenter (0195) maintained that even if the EPA could legally go back and change the existing MACT standards, it could not reasonably make those revised standards effective immediately. According to the commenter, sources subject to the Proposed Rule would be expected to comply with revised SSM requirements as soon as the rule becomes effective. The commenter argued that it would be arbitrary and capricious for the EPA to require compliance immediately, when CAA section 112(i) allows a compliance deadline of up to three years. The commenter observed that elimination of the SSM provisions in the existing rules could require plants to make significant changes to their production processes or their HAP collection and control systems, which would take significant time for design, engineering, acquisition, and installation.
Response: We disagree that we lack justification for making rule changes to remove the vacated SSM provisions effective upon promulgation. As discussed above, the D.C. Circuit Court's vacature of SSM provisions in its Sierra Club decision rendered those provisions null and void prior to this rulemaking. EPA issued a letter dated July 22, 2009 from Adam Kushner, Director, Office of Civil Enforcement, to various parties that addressed the impact of the decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008). The mandate implementing the court's decision was issued on October 16, 2009, at which time the vacated SSM provisions were clearly no longer in effect, and standards in subpart RRR applied at all times. The rule changes to remove the SSM provisions from subpart RRR are ministerial actions by EPA to reflect the vacature by the court. In addition, amendments to subpart RRR were proposed on February 14, 2012, at which time secondary aluminum plants were put on notice of the specific wording changes to subpart RRR. Thus, facilities have had ample notice of the SSM rule changes.
5.2 	Startup and Shutdown
Comment #1: Commenters (0193, 0194) suggested that the entire paragraph at §63.1516(b)(1)(v) in the current Subpart RRR rule needs to be deleted. The commenters noted that this paragraph refers to actions taken under a startup, shutdown and malfunction (SSM) plan, and the proposed rule removes SSM Plan requirements.
Response: The commenter is correct and this paragraph has been deleted.
Comment #2: Commenters (0193, 0194, 0197) stated that the EPA has not evaluated or justified applicability of the existing MACT emission limits to startup, shutdown or malfunction periods. The commenters noted that the current MACT limits are based on performance tests conducted during normal process operation, not during SSM periods. Commenter 0192 noted that current work practices used by the industry during startup and shutdown of batch-operated furnace are adequate and regulatory requirements are not necessary.
Commenters (0192, 0199) asserted that the EPA's 2012 proposal to use the feed rate determined in the performance test to calculate production normalized emission rates during startup and shut down is inappropriate. The commenters explained that during startup and shutdown periods, little or no amount of aluminum is in a batch-operated conventional melting furnace, and thus no aluminum smelting-related emissions. The commenters observed that the zero production number during those startup and shutdown periods creates mathematical problems when calculating pounds per ton or micrograms per megagram production normalized emissions.
One commenter (0195) stated that the commenter's members do not have sufficient information to comment on whether in fact the emissions during startup and shutdown of the sources subject to the 2012 proposed rule will be no greater than emissions during normal operations, but expressed the opinion that the EPA has not adequately justified this conclusion. The commenter cited the possibilities that a control device may be less efficient until it reaches its design operating temperature, it may be less efficient when the pollutant concentrations in the gases to be treated are lower than during steady-state operation, or until a manufacturing process reaches steady-state operation, that process may generate substantially higher emissions, either on a total-mass basis or on a mass-per-unit-of-production basis.
The commenter suggested that the EPA conduct a thorough analysis and determine whether it is representative of the performance of best-performing sources (the MACT floor) to require facilities in these source categories to achieve the same emission limitation during startup and shutdown as during normal operations, and that the default assumption be that such special provisions during startup and shutdown are needed. The commenter asked that the EPA provide a factual analysis supporting the EPA's new conclusion that MACT standards can be achieved as well during all startup and shutdown periods.
The commenter expressed skepticism about whether the EPA conducted a sufficient analysis to demonstrate the achievability of the MACT emission limits established for normal operations during startup and shutdown events, because of likely limitations in the available data. The commenter stated that because of the difficulties in collecting reliable data during startup and shutdown periods, the EPA may have understated startup and shutdown emissions.
The commenter noted that it can be unclear whether a condition that leads to excess emissions should be characterized as a startup or shutdown event or a malfunction event, and the EPA may be analyzing data sets that exclude events that were treated as malfunctions but should be included in calculating average performance as startup or shutdown conditions.
Response: The commenters suggested that the EPA did not adequately analyze the ability of affected sources to meet Subpart RRR MACT emissions limits during startup and shutdown, but the EPA did provide an explanation of the basis for its approach in the 2012 proposal, including the EPA's conclusion that emissions during startup and shutdown will be low, and the commenters did not submit specific information to indicate that different standards are justified or to explain specifically why subpart RRR MACT standards are overly stringent during startup or shutdown. This failure to provide specific information to support their claims of unachievability is especially notable because the Subpart RRR MACT standards have already applied at all times, including periods of startup and shutdown, since the SSM exemptions incorporated into Subpart RRR were vacated in the Sierra Club decision. The EPA disagrees with the suggestion that there is a "default assumption" that "special provisions during startup and shutdown are needed". The commenters also do not identify or justify any specific different standards that should apply during startup and shutdown.
For secondary aluminum production processes where the MACT standards are expressed in units of pounds per ton of feed or similar units (i.e., thermal chip dryers, scrap dryer/delacquering kiln/ decoating kilns, dross-only furnaces, inline fluxers using reactive flux and group 1 furnaces), the 2012 proposal included (and this final rule includes) an alternative method for demonstrating compliance with those limits based on emissions measured during startup and shutdown. In response to the commenters' concern that the absence of feed/charge during startup and shutdown will result in a zero production and create mathematical problems when calculating production-based emissions, the final rule specifies that the feed/charge rate used in the calculation come from the most recent performance test associated with a production rate greater than zero, or the rated capacity of the affected source if no prior performance test data are available.
In response to comments on the 2012 proposal and because conducting meaningful emissions testing during periods of startup and shutdown can be problematic, we proposed in the 2014 supplemental proposal (and are finalizing in this rule) an additional alternative method for demonstrating compliance with production-based subpart RRR emission limits during periods of startup and shutdown. As we explained in the 2014 supplemental proposal, these alternative compliance provisions reflect the MACT requirement for these periods. Specifically, compliance with production-based emission standards during startup and shutdown can be demonstrated by keeping records that show that the feed/charge rate was zero, the flux rate was zero and the affected source or emission unit either was heated with electricity, propane or natural gas as the sole sources of heat or was not heated. This alternative compliance method was based on the recognition that the source of HAP emissions is the processing of scrap and the use of fluxes during processing and that the heat for processing in this source category is generated exclusively by use of clean fuels -- natural gas, propane or electricity. The following records must be kept for sources that use this alternative method of compliance: the date and time of each startup and shutdown, the quantity of feed/charge and flux introduced during each startup and shutdown and the types of fuel used to heat the unit during startup and shutdown.
Section 112(h) allows the EPA to set work-practice standards when "the application of measurement methodology to a particular class of sources is not practicable due to technological and economic limitations." Section 112(h) "allows the EPA to substitute work practice standards for emission floors only if measuring emission levels is technologically or economically infeasible." Sierra Club v. EPA, 479 F. 2d 875, 880 (D.C. Cir. 2007). We specifically sought comment in the 2012 proposal on whether work practices should be applied for processes subject to production-based limits (i.e., standards expressed in units of pounds per ton of feed or similar units). We asked any commenters who supported the application of work practices to explain how the requirements of CAA section 112(h)(2) are met and to identify work practices that would be effective in limiting HAP emissions during periods of startup and shutdown for such processes. We did not receive and do not have information, from commenters or otherwise, concerning the impracticability of applying measurement methodology that would be necessary to prescribe work practice standards for periods of startup and shutdown in lieu of numerical emission standards contained in Subpart RRR.
We have reviewed the information available to us regarding startup and shutdown periods. Prior to the 2012 proposal we conducted an industry survey for emissions data including a request for information on emissions during startup and shutdown, but no such information on startup and shutdown emissions was received. A commenter notes the limited data available to the EPA, but neither this nor any other commenter submitted additional data on startup and shutdown emissions. Because scrap and reactive fluxing are the source of HAP emissions, we believe that startup and shutdown emissions will be very low and are not likely to cause a violation of the standards. We found no evidence that suggests that emissions are higher during startup or shutdown that might indicate a need for a different standard for these periods. The commenters have not provided any information to support a conclusion that sources cannot comply with the standards as proposed, and have not provided information to support development of different standards for startup and shutdown periods. Contrary to a commenter's argument, we believe that the Subpart RRR MACT standards provide "continuous section 112-compliant standards".
As we stated in the 2012 and 2014 proposals, the scrap processed and reactive fluxing used at secondary aluminum production facilities is the source of emissions. For that reason, we continue to expect that emissions during startup and shutdown will be no higher and probably much lower than emissions during normal operations since no scrap will be processed, even if, as the commenter suggests, control equipment is operating at less than optimal efficiency. We know of no reason why facilities should not be able to comply during periods of startup and shutdown. We recognize that there is no charging during startup and shutdown periods. For that reason we proposed and are finalizing two alternative methods for demonstrating compliance with production-based emission limits during periods of startup and shutdown.
Thus, we set standards based on available information as directed by section 112. The Subpart RRR standards that apply during normal operation will also apply during startup and shutdown.
In response to comments received, we proposed in the 2014 supplemental proposal and are finalizing, with some revisions, definitions of startup and shutdown. See Comment #3 below.
Finally, as in 40 CFR 63.7(e)(1), we are requiring in 40 CFR 63.1511(b)that performance tests conducted under this subpart not be conducted during malfunctions because conditions during malfunctions are often not representative of normal operating conditions. The EPA is adding language in 40 CFR 63.1517(b)(19) that requires the owner or operator to record the process information that is necessary to document operating conditions during the test and include in such record an explanation to support that such conditions are representative of startup and shutdown operations.
Comment #3: One commenter (0197) stated that startup and shutdown periods are not defined in the rule, but rather only in the preamble to the proposed rule. The commenter supported the EPA's definitions of startup and shutdown periods but, to reduce uncertainty, urged the EPA to include these definitions in the rule.
In a comment on the supplemental proposal, commenter 0288 stated that the definition of "startup" and "shutdown" were problematic as applied to reverberatory furnaces. The commenter stated that the proposed definition of "shutdown" appears to require that a group 1 reverberatory furnace be tapped empty before shutdown can be said to have begun. The commenter stated that the implication is that emissions testing should include tapping the furnace until empty. According to the commenter, group 1 reverberatory sidewell furnaces cannot be tested under this definition, which would require the furnace cycle to include a complete drain and refilling. The commenter stated that filling a reverberatory furnace from an empty condition can take 12 hours or more depending on furnace size and design. According to the commenter, this is not a representative (normal) condition when operating a reverberatory sidewell furnaces, which operates with a heel of molten metal at all times during normal operation. The commenter stated that a common practice when starting a reverberatory sidewell furnace from an empty condition is to use clean charge and no reactive flux until the molten heel is raised above the arch between the sidewell and main hearth; once this arch is covered, normal charging and fluxing practices can begin.
The commenter stated that a group 1 rotary furnace can be tested beginning empty and finishing empty. Although this does not represent every furnace cycle it does represent one of the normal operating modes for this furnace type. The commenter suggested that, to accommodate normal operating procedures for both reverberatory and rotary group 1 furnaces, the definition of "shutdown" be revised to the following:
      "...that begins when the introduction of feed/charge is halted with the intention of removing all product and the intention of allowing the equipment to reach ambient temperature."
In a comment on the supplemental proposal on the definition of "startup," commenter 0288 referred the EPA to their comment on the definition of "shutdown," and added that a reverberatory sidewell furnace, from a cold start, must be heated to normal operating temperatures while feed/charge is added. The commenter stated that this feed/charge normally is made up of clean charge and no reactive flux and once the furnace heel is at normal operating levels (above the arch), normal charging can proceed. The commenter suggested the definition of "startup" be revised to the following:
      "... Startup ends at the point that feed/charge other than clean charge is introduced."
Commenter 0288 stated that the startup record required in paragraph 63.1517(b)(18) should include either identifying all materials charged to the furnace during startup or certification that only clean charge and no reactive flux was used until the arch between the sidewell and main hearth was covered. The commenter recommended that 63.1517(b)(18) be revised to the following:
      "For each period of startup or shutdown for which the owner or operator chooses to demonstrate compliance for an affected source based on a feed/charge rate, other than clean charge, of zero, a flux rate of zero, ..."
Commenter 0288 stated that for the same reasons, the type of charge along with quantity should be recorded. The commenter suggested that paragraph 63.1517(b)(18)(ii) be revised to the following:
The type and quantity of feed/charge and quantity of flux introduced during each startup and shutdown, and ..."
In a comment on the supplemental proposal with regard to the definition of "shutdown," commenter 0289 requested a clarification with how the definition relates to rotary tilt-type reverberatory furnaces, which operate on a batch-cycle. The commenter stated that, as proposed, the definition would classify the period between batches of this type of furnace, however brief and regularly scheduled, as a shutdown. The commenter stated that because this has implications for secondary aluminum processing units (SAPUs), and how emissions from members of a SAPU are counted, clarification as to whether the time between batches is a shutdown is appropriate.
In a comment on the supplemental proposal, commenter 0290 stated that they disagree with the proposed definition of shutdown in the supplemental proposal as it does not describe a furnace shutdown. The commenter stated that when a furnace is shutdown it is taken to a cold condition. The commenter stated that many melting and holding furnaces are operated batch-wise and between batches the furnace is still in operation and temperature is being maintained; the furnace is in a stand-by condition until the next batch is started. The commenter stated that the definition as proposed would apply between every batch and trigger burdensome record keeping requirements without any additional environmental benefit.
In a comment on the supplemental proposal, commenter 0294 stated that the typical operation of emission units within this source category are, for the most part, batch operations, i.e., feed/charge is introduced, feed/charge is halted, feed/charge previously fed into the emission unit is processed, and all of that feed/charge is subsequently removed from the emission unit; then another batch is begun and the cycle repeats itself. The commenter stated that as proposed, an affected facility would be shutting down numerous times daily as part of its normal batch operating mode; the commenter does not believe it was the EPA's intent to include in the definition of shutdown these periods of normal operations or to create unnecessary recordkeeping and reporting burdens for owners and operators. The commenter stated that they agree that the halting of feed/charge and the removal of product from the emission unit are aspects of a shutdown; however, there are other key aspects of a shutdown that must be incorporated into the definition; those aspects are the discontinuation of heat input and the reduction of the functional temperature of the emission unit. The commenter recommended that the EPA redefine "shutdown" to mean
      "...the period of operation that begins when the introduction of feed/charge is intentionally halted, all product has been removed from the emission unit (e.g., by tapping a furnace), the source of heat is removed from the emissions unit, and a shutdown concludes when the emission unit has cooled to near ambient temperatures."
In a comment on the supplemental proposal, commenter 0295 stated that the proposed definition of a furnace shutdown in not accurate in that it would consider furnaces to be `shutdown' in situations when they are in stand-by mode in between processing batches of metal with the furnace still in operation, the temperature maintained at or near normal operating levels, and any applicable air pollution control equipment operating. The commenter recommended that the definition be revised to indicate that `shutdown' is a situation where the furnace temperature is brought to ambient after the metal charge has been removed to the greatest extent practicable as follows:
      "Shutdown means the period of operation ... that begins when the introduction of feed/charge is halted, the heat sources have been turned off, and all product has been removed from the emission unit to the greatest extent practicable (e.g., by tapping a furnace). Shutdown and ends when the emission unit is at or near ambient temperature."
In a comment on the supplemental proposal, commenter 0290 stated that the EPA correctly recognizes in the definition of startup that a shutdown furnace is in a cold condition by including the phase "warming from a cold start or a complete shutdown". The commenter recommended that the EPA add the phrase "the burners are turned off and the furnace is being taken to a cold state" to the proposed definition of "shutdown."
In a comment on the supplemental proposal, commenter 0289 stated that in the proposed definition of "startup," startup "begins with equipment warming up from a cold start or a complete shutdown." The commenter stated that there is no explanation for what constitutes a "complete" shutdown as opposed to the proposed definition of "shutdown" or how it differs from a "cold start." The commenter requested a clarification to forestall interpretation issues.
In a comment on the supplemental proposal, commenter 0295 stated that they have concerns with the definition of `startup' and recommended that the definition of startup be revised as follows:
      "Startup means the period of operation ... that begins with equipment warming from at or near ambient temperature. Startup ends at the point that flux or feed/charge is introduced."
Response: In response to comments on the 2012 proposal, the EPA included definitions of startup and shutdown in regulatory text for the 2014 supplemental proposal. We reviewed the comments on the supplemental proposal including those expressing concerns over the proposed definitions of "startup" and "shutdown," and the final rule addresses those concerns. In particular we revised the definitions to account for the fact that many furnaces are batch operations and are often in a standby condition that, under the proposed definitions, might have been considered to be shutdown. Also, we agree that the definition of "shutdown" should recognize that the beginning of shutdown includes halting of feed/charge, turning off the heat sources, and removal of product to the greatest extent practicable, and shutdown ends with cooling of the equipment to near ambient temperature. By modifying the definition of shutdown to begin after the removal of the heat source and to include cooling of the emission unit to near ambient temperature, the final rule distinguishes emission units that are shutting down from those that are in standby mode. The definition of startup also includes the introduction of flux as an end to startup. The final definition also recognizes that, after tapping, most furnaces (tilting furnaces are an exception) retain a molten metal heel and are not emptied completely. Regarding the definition of "startup," we disagree with commenter 0288's suggestion to revise the definition to state that startup ends with the addition of feed/charge "other than clean charge." The result of such a change would be that group 2 furnaces would never exit the startup mode. The commenter has not identified, nor do we envision any negative effects on sidewell furnaces if the definition of "startup" results in startup ending before the molten metal level reaches the top of the arch between the sidewell and the hearth. The final rule defines "shutdown" and "startup" for this source category as follows:
 Shutdown means the period of operation for thermal chip dryers, scrap dryers/delacquering kilns, decoating kilns, dross-only furnaces, group 1 furnaces, in-line fluxers, sweat furnaces and group 2 furnaces that begins when the introduction of feed/charge is intentionally halted, the source of heat to the emissions unit is turned off, and product has been removed from the emission unit to the greatest extent practicable (e.g., by tapping a furnace). Shutdown ends when the emission unit is near ambient temperature.
 Startup means the period of operation for thermal chip dryers, scrap dryers/delacquering kilns, decoating kilns, dross-only furnaces, group 1 furnaces, in-line fluxers, sweat furnaces and group 2 furnaces that begins with equipment warming from a shutdown, that is, the equipment is at or near ambient temperature. Startup ends at the point that flux or feed/charge is introduced.
Comment #4: One commenter (0197) indicated that the startup and shutdown emission calculation provision is confusing, may result in over reporting of emissions, and should be revised. The commenter indicated that the procedure is not a calculation of emissions, but rather an emission rate, and that according to the EPA's definition, there is no product (aluminum chips) in a unit during startup and shutdown periods and would therefore yield zero emissions. The commenter indicated that, with the exception of scrap shredders, emissions from sources covered by this subpart during these periods can be concluded to include only the byproducts of combustion. The commenter stated that these emissions, particularly in the case of dioxins and furans, should be negligible and may be accurately estimated using AP-42 emission factors or an engineering evaluation. The commenter recommended that the EPA should clarify the wording of the emission calculation equation and also allow facilities the option to demonstrate compliance with the standards through the use of AP-42 emission factors or an engineering evaluation. The commenter remarked that the EPA should not finalize a rule that inappropriately assumes emissions during startup are based on worst case emissions calculated during a performance test.
Response: We have revised the startup and shutdown emission calculation provisions in section 63.1513(f)(2) of the final rule to clarify how the owner or operator would be able to demonstrate compliance for those affected sources subject to an emissions limit expressed in units of pounds per ton of feed, or ug TEQ or ng TEQ per Mg of feed. As a further alternative to measuring emissions during startup and shutdown and dividing by the feed rate from the most recent performance test associated with a production rate greater than zero (or the rated capacity of the affected source if no prior performance test data is available), we are also allowing that records of feed or charge to the furnace may be used to demonstrate that the furnace is in compliance with the emissions limits during startup and shutdown. Because the source of HAP emissions is the feed or charge material and reactive flux material, emissions during startup and shutdown should be appreciably lower than the emissions limits. The EPA is, therefore, allowing sources to use recordkeeping to demonstrate compliance with the standards during startup and shutdown as an alternative to stack testing. The owner or operator would keep records showing that during startup and shutdown, the feed/charge rate was zero, the flux rate was zero and the affected source or emission unit was heated with electricity, propane or natural gas as the sole sources of heat or was not heated, although by definition, if feed or charge is introduced into the process, the affected source is not operating in a startup or shutdown mode and the requirements for normal operations would apply.
Comment #5: In a comment on the supplemental proposal, Commenter 0294 stated that their standard safe work practices and standard operating procedures do not allow reactive flux or feed/charge materials to be added to furnaces, in-line flux boxes and other affected sources during a startup; for this reason, startup emissions are negligible and well below MACT emission limits. The commenter stated that documenting these work practices and procedures for every startup is an unnecessary recordkeeping burden and provides no environmental benefit. The commenter stated that all of their affected sources use either natural gas or electricity for heat and keeping a record of the types of fuel used to heat the unit for every startup also adds no value. The commenter recommended that the EPA should allow these facilities the option to submit an annual compliance certification stating that no flux and or feed/charge material was added and no heat source other than electricity, propane or natural gas was used during startup of the affected source. The commenter stated that the proposed records at §63.1517(b)(18) make no sense for shutdowns because, by definition, a shutdown begins when heat is removed and the introduction of feed/charge is halted; so, if there was no "lack of heating" or the flux rate and charge rate were greater than "zero", the source would not be in "shutdown" by definition. The commenter recommended that the proposed records at section 63.1517(b)(18) be deleted and replaced with a compliance provision in section 63.1516 (b)(2) that reads:
      "For each affected source choosing to demonstrate startup compliance based on §63.1513(f)(1): During each startup, no reactive flux and no feed/charge material was added to the emission unit and electricity, propane or natural gas was used as the sole source of heat."
Response: We agree with the commenter that where a facility adheres to standard practices and procedures during startup and shutdown that exclude the addition of flux and feed/charge materials to emission units or the use of heat sources other than electricity, propane or natural gas, or is not heated, requiring the facility to document these practices for every startup and shutdown would be unnecessary and burdensome where there is an alternative method for documenting compliance during startup and shutdown. While we agree that documenting the work practices and procedures for startups/shutdowns under the conditions described can be reduced, we don't agree that annually is sufficient and are requiring documentation every 6 months. In the final rule, section 63.1517(b)(19) gives sources that choose to demonstrate compliance based on the startup and shutdown recordkeeping provisions of section 63.1513(f)(1), the option of submitting a semiannual report in accordance with section 63.1516(b)(2) of the final rule certifying that during startup and shutdown , no flux and no feed/charge were added to the emission unit, and electricity, propane or natural gas were used as the sole source of heat or the emission unit was not heated.
Comment #6: In a comment on the supplemental proposal, commenter 0298 stated that the proposed definitions that would delineate periods of startup and shutdown, during which alternative requirements would apply, as well as an alternative method for determining compliance are directionally consistent with portions of their comments on the 2012 proposal that urged the EPA to look more carefully at the Agency's assumption that facilities could meet limits based on normal operations during startup and shutdown just because less raw materials and fuel would be used during those periods.
Response: The EPA acknowledges the commenter's support of the rule requirements for demonstrating compliance during periods of startup and shutdown. See above for responses to specific comments on the definitions of startup and shutdown and alternative methods for demonstrating compliance with production-based emission limits during startup and shutdown.
Comment #7: One commenter (0195) stated that the EPA in the 2012 proposal has not justified adding proposed §63.1511(a) and eliminating reference to the NESHAPs General Provision on representative performance testing, §63.7(e)(1). The commenter asserted that the D.C. Circuit did not vacate the provision the EPA proposes to replace, §63.7(e)(1), in Sierra Club v. EPA, and according to the commenter, §63.7(e)(1) does not refer to or rely on provisions that were vacated in Sierra Club v. EPA. The commenter argued that the Sierra Club decision does not authorize the EPA to (1) change existing MACT standards so that the EPA, in turn, could (2) direct a source to conduct performance testing during abnormal operations, such as startups, shutdowns or malfunctions.
The commenter argued that requiring sources now to demonstrate compliance with numerical emission limitations in the existing MACT standards, using performance tests or continuous monitoring, even while the source is in startup or shutdown mode or is experiencing a malfunction, definitely has the effect of making those existing MACT standards more stringent. The commenter asserted that the EPA cannot simply "amend" existing MACT standards in a way that can make those standards more stringent without (a) providing an adequate justification for departing from the EPA's previous judgment about the appropriate level of the standards and the appropriate conditions for performance testing and (b) demonstrating that the revised standards would still meet the criteria of CAA section 112(d). The EPA's total failure to do so renders the Proposed Rule inadequate notice for public comment. If the EPA wishes to change the performance tests applicable to the existing MACT standards, making them more stringent, then it must at a minimum withdraw and re-propose the requirements, with adequate explanation and justification.
Response: As noted by the commenter, in addition to our ministerial action removing the vacated SSM exemption from emission standards (codified in General Provisions sections 63.6(f)(1) and (h)(1), formerly made applicable to this source category in Appendix A to Subpart RRR, and vacated by the Sierra Club decision), we also made inapplicable to this source category the SSM exemption from performance testing (see General Provisions section 63.7(e)(1)). The categorical exemption from performance testing for periods of SSM made sense when SSM periods were exempt from emission standards. Such an exemption is no longer appropriate because emission standards now apply at all times for this source category. Instead, the final rule provides in section 63.1511(a) that "[p]erformance tests shall be conducted under such conditions as the Administrator specifies to the owner or operator based on representative performance of the affected source for the period being tested." In addition, the final rule provides that performance tests should not be conducted during malfunctions. See section 63.1511(b).
The removal of the exemption from performance testing for periods of startup and shutdown does not affect the stringency of the underlining emission standards nor does it alter the basic requirement that performance tests be conducted under conditions based on representative conditions. We note that subpart RRR requires initial performance tests in section 63.1511(b) and periodic performance tests every 5 years for major sources in section 63.1511(e), but these provisions do not necessarily require that performance tests be conducted during startup and shutdown periods, although the EPA maintains authority under Subpart RRR and the Clean Air Act to require such testing as appropriate. Sections 63.1511 and 63.1512 specify conditions and procedures for performance testing for this source category, some of which have been revised in this rulemaking as discussed in the preambles to the proposed and final rules, and elsewhere in the response to comments. In addition, we are finalizing two alternative methods for demonstrating compliance with production-based emission limits during periods of startup and shutdown, including one alternative method that relies on recordkeeping and not on performance testing. We note that the latter alternative method was proposed in the 2014 supplemental proposal, subsequent to Commenter 0195's comments on the 2012 proposal.
5.3 	Malfunction and Affirmative Defense
Comment #1: A commenter (0190) recommended that the EPA modify the affirmative defense provisions so that it is a "rebuttable presumption." The commenter was concerned that allowing a facility to interpose an affirmative defense for violations caused by malfunctions implies that the facility is guilty until proven innocent and improperly shifts the burden to the facility. Therefore, the commenter suggested that the EPA establish a rebuttable presumption (rather than affirmative defense) where it is presumed that any violation occurring during the malfunction was not the facility's fault unless the Agency proves certain facts that are enumerated in the rules. This will allow the Agency to challenge the alleged deviation without compromising the legal rights of either party.
While commenter 0190 would prefer the EPA use a rebuttable presumption, should the Agency keep the affirmative defense concept, the commenter suggested the following modifications to the language to make it more usable. The commenter suggested the EPA should drop the reference to "any" activity. There were also several references to "All" that would make it difficult to satisfy the requirements of an affirmative defense. In addition, the language in the provision was contradictory. In paragraph (a), the phrase "preponderance of evidence" was used while later in that paragraph (iii), the language referred to "any activity" meaning that more than preponderance of evidence was needed. This same trend occurred in paragraphs (5)  -  "All possible," (6) "All," (7) "All of the actions," and (8) "At all times." While "all" would include "preponderance," "preponderance" does not mean all of the time. The commenter suggested that the phrase "preponderance of evidence" is adequate and the references to "all" and "any" in the later paragraphs should be modified.
Commenter 0190 believed that a formal "root cause analysis" (as the term is understood by many engineers) should only be used when other reasonable methods fail to show what caused the malfunction or when the serious nature of an event might make such an analysis necessary. Moreover, other tools may be more appropriate (e.g., failure mode and effect, fault tree, etc.) or more powerful tools may be introduced in the future. The facility is the only one that can and should decide what tool to use to determine the cause of the malfunction. The commenter noted that to some companies and local regulators, the term "root cause analysis" implies a specific formal process. The commenter indicated that there are several techniques that may be called "root cause analysis," depending on the author and industry. If the EPA intended for the facility to investigate and fix the source of the malfunction so that it is less likely to recur, the commenter supported that concept but suggested that the Agency use an alternative term that does not carry a specific meaning. However, if the Agency envisioned a formal process for determining the root cause for every malfunction, no matter how simple, the commenter believed that this is unnecessary and would result in excess efforts with no environmental gains.
The commenter also noted that it is impossible to eliminate the causes for certain malfunctions (e.g., lightning strikes).
One commenter (0190) also noted that the EPA does not allow facilities to assert an affirmative defense for the exceedance of an emission limit during malfunctions if the EPA is seeking to enforce that emission limit through injunctive relief. The commenter stated that the Agency took that position based on a memorandum, State Implementation Plans: Policy Regarding Excessive Emissions During Malfunctions, Startup, and Shutdown at 2 (Sept. 20, 1999) (SIP SSM Memo). The commenter asserted that this policy is wrong and that the type of legal action or relief should have no bearing on the availability of this defense. The commenter concluded that the type of legal action the EPA uses to enforce a violation of its emission limits is simply irrelevant to whether the violation should be excused because of circumstances beyond the facilities control.
The commenter (0190) continued that not allowing an affirmative defense in an action for injunctive relief is arbitrary and capricious. As the D.C. Circuit Court stated in Essex Chem. Corp. v. Ruckelshaus, 486 F.2d 427. 433 (D.C. Cir. 1973) a case reviewing a § 111 rule, the court held that startup, shutdown, or malfunction ("SSM") provisions are "necessary to preserve the reasonableness of the standards as a whole." The D.C. Circuit Court of Appeals has also noted that "[a] technology-based standard discards its fundamental premise when it ignores the limits inherent in the technology." NRDC v. EPA, 859 F.2d 156, 208 (D.C. Cir. 1988). Therefore, the commenter indicated that the EPA should not apply a policy drafted to "ensure that SIPs provide for attainment and maintenance of the national ambient air quality standards ("NAAQS") and protection of prevention of significant deterioration (PSD) increments" and other risk-based programs, SIP SSM Memo at 2, to the CAA § 129 technology-based program.
Commenters (0190, 0193, 0194) suggested that the EPA clarify affirmative defense provisions by modifying the regulatory language in § 63.11501(e) to address the commenters' concerns and to make an affirmative defense a more useful tool (using strikeout to show text deleted and underline to show text added):
      § 63.1520 Affirmative defense for violation of emission limit during malfunction.
      In response to an action to enforce the standards set forth in this subpart, you may assert an affirmative defense to a claim for civil penalties for violations of such standards that are caused by malfunction, as defined at § 63.2. Appropriate penalties may be assessed, however, if you fail to meet your burden of proving all of the requirements in the affirmative defense. The affirmative defense shall not be available for claims for injunctive relief.
      (a) To establish the affirmative defense in any action to enforce such a limit, you must timely meet the notification requirements in paragraph (b) of this section, and must prove by a preponderance of evidence that`:
      (1) The excess emissions:
      (i) Were caused by a sudden, infrequent and unavoidable not reasonably preventable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner; and
      (ii) Could not have been reasonably prevented through careful planning, proper design or better operation and maintenance practices; and
      (iii) Did not stem from any activity or event that could have been reasonably foreseen and avoided, or planned for.
      (iv) Were not part of a recurring pattern indicative of inadequate design, operation, or maintenance; and
      (2) Repairs were made as expeditiously as possible when the applicable emission limitations were being exceeded. Off-shift and overtime labor were used, to the extent practicable to make these repairs; and
      (3) The frequency, amount and duration of the excess emissions (including any bypass) were minimized to the maximum extent practicable during periods of such emissions; and
      (4) If the excess emissions resulted from a bypass of control equipment or a process, then the bypass was unavoidable to prevent loss of life, personal injury, or severe property damage; and
      (5) All possible Reasonable steps were taken to minimize the impact of the excess emissions on ambient air quality, the environment and human health; and
      (6) All emissions monitoring and control systems were kept in operation if at all possible, consistent with safety and good air pollution control practices; and
      (7) All of the actions in response to the excess emissions were documented by properly signed, contemporaneous operating logs; and
      (8) At all times, the affected source was operated in a manner consistent with good practices for minimizing emissions; and
      (9) A written root cause analysis report has been prepared, the purpose of which is to determine, correct, and eliminate mitigate the primary causes of the malfunction and the excess emissions resulting from the malfunction event at issue. Facility personnel will determine the appropriate type of analysis required (may include but not limited to root cause analysis, failure mode and effect, fault tree, etc.) to identify the cause of the malfunction. The analysis report shall also specify, using best monitoring methods and engineering judgment, the amount of excess emissions that were the result of the malfunction.
      (b) Reports. The owner or operator seeking to assert an affirmative defense shall submit a written report to the Administrator within 45 days of the initial occurrence of the violation of the standards in this subpart, which may be the end of any applicable averaging period, to demonstrate, with all necessary supporting documentation, that it has met the requirements set forth in paragraph (a) of this section. The owner or operator may seek an extension of this deadline for up to 30 additional days by submitting a written request to the Administrator before the expiration of the 45 day period. Until a request for an extension has been approved by the Administrator, the owner or operator is subject to the requirement to submit such report within 45 days of the initial occurrence of the violation. A written report to demonstrate, with all necessary supporting documentation, that you have met the requirements set forth in paragraph (a) of this section. This report should be submitted as a part of the excess emissions and continuous monitoring system performance report and summary report as required in § 63.10(e)(3).
One commenter (0194) stated that the proposed affirmative defense language for periods of malfunction needs clarification and revision to make it usable. The commenter asserted that the proposed affirmative defense language is similarly made unusable by numerous limitations such as "could not have been prevented", "could have been foreseen and avoided", "all possible steps", "at all times" and "all actions ...documented". The commenter stated that this language so narrowly limits the affirmative defense that the provisions would have no practical application and provide no real legal defense for owners and operators, who are the intended users.