One commenter (IV-D-31) wanted flux monitoring on a monthly basis and the schedule requirement eliminated.  The rule could be interpreted to preclude a system with computerized monitoring of furnace operations/controls with correlated emissions and online continuous emissions calculations.
      Response:  Owners or operators are required to conduct performance tests under the highest load or capacity reasonably expected to occur. This is represented by the maximum reactive flux rate.  The final rule provides that sources may flux (on a lb per ton of feed/charge basis), up to the limit established during a successful performance test and does not require maintaining the same schedule.  The rule also does not require owners or operators to use more flux than necessary to produce a saleable product.  These requirements will not lead to increased HCl emissions.
      Reactive flux monitoring on a monthly basis is not acceptable in that it is inconsistent with the emission standards based on 3-day 24-hour rolling averages and the established monitoring parameter values or ranges derived during the performance test.  Monitoring over a period consistent with the basis of the emission standards provides the necessary evidence of continuous compliance.
      The issue of flux injection rate and schedule is related to lime injection practice for the FF control systems.  The final rule provides operating requirements for the floor technology, continuous lime injection systems with lime-injected fabric filters.  Owner/operators who want to use intermittent lime feed systems (as opposed to continuous injection) must show compliance with the emission limits and must apply to the permitting authority for approval of an alternative lime addition monitoring procedure.  The owner/operator must provide information as necessary to show that the applicable emission limits will be achieved on a continuous basis.

      The rule does not preclude the use of computerized systems that correlate controls and operating practices with emissions and calculate emissions on a continuous basis once this approach is approved by the permitting authority and incorporated into the site-specific OM&M plan.

      3.2.7  Comment:  Several commenters  (IV-D-11, IV-D-17, IV-D-22,IV-D-23) disagreed with the +25 F associated with the inlet temperature limit for FF established during the initial performance test.  According to two commenters (IV-D-17, IV-D-23) the operating temperature of these FF will vary more than 25 F due to changes in ambient temperature.  This creates an unnecessary risk of violation and provides no environmental benefit. Another commenter (IV-D-11) stated that instead of the temperature requirement, electrochemical HCl sensors for automatic lime feed adjustment and other automatic systems should be considered to allow greater operating flexibility.  One commenter (IV-D-17) stated that in-line fluxers are not regulated for dioxin emissions and therefore do not need a temperature limit.
      Response:  The final rule has been changed to eliminate this requirement for fabric filters used only to control in-line fluxers since these units operate at temperatures that are close to ambient temperature.  For other affected sources and emission units, or fluxers ducted to a device cocontrolling other emission units, the +25 F limit is retained.  Operators commonly use  dilution air or water sprays as required to maintain the FF inlet temperature within the range.  Also, performance tests could be conducted at worst case conditions.  For example, performance tests could be conducted so that the inlet temperature is much higher than the normal operating inlet temperature (450 F vs 380 F, for example) thus providing a larger operating range.  Dioxin formation is strongly influenced by the temperature at the FF inlet, and temperature control is the means of preventing D/F formation (and enhancing HCl removal) in the fabric filter.  Temperature is also a parameter which is monitored to ensure continuous compliance between periodic performance tests.  This is because it is an indicator of control device performance for D/F and HCl emissions.

      3.2.8  Comment:  According to one commenter (IV-D-32), owners and operators could demonstrate compliance with the HCl emission limit by monitoring total chlorine input and showing it to be less than the emission limit.
      Response:  The EPA agrees, for in-line fluxers and group 1 furnaces processing only clean charge, operators may demonstrate compliance with the HCl emission standards (in lieu of performance tests) by demonstrating that reactive flux injection is limited to a rate which would not exceed the SAPU standard if emitted in its entirety.  However, the operators must also show the affected sources or emission units are meeting the PM limit as well.

      3.2.9 Comment:  One commenter (IV-D-24) stated that there are two sections 1506(g)(2) in the proposed rule.

      Response:  The commenter is mistaken.

      3.2.10 Comment:  One commenter (IV-D-31) wanted a SAPU wide bubble on flux and lime monitoring.
      Response:  Flux and lime monitoring is required to ensure that emissions do not increase above the level measured during a successful performance test.  A SAPU wide bubble would, for example, allow all of the flux to be added to one furnace and all of the lime to a FF controlling a different furnace.  This would not ensure continuous compliance with the standard, and would permit affected sources and emission units to operate with less than the MACT floor level of control.

      3.2.11 Comment:  Several commenters (IV-D-17, IV-D-22, IV-D-23) agreed with the selection of temperature as an operating parameter for FF used on group 1 furnaces and delacquering/drying kilns with FF, but disagreed with requirement to maintain the inlet temperature within +25 F of the performance test value. Two commenters (IV-D-17, IV-D-23) claimed most FFs operate in range of 300-350 F to protect bags and want to allow 50 F above that determined during performance test instead of 25 F.  They stated that EPA has not shown that HCl adsorption is a strong function of temperature at 350 F. One commenter (IV-D-22) recommended that the temperature simply be limited to 400 F.  One commenter (IV-D-11) further disagreed with the requirement to maintain temperatures for delacquering kiln afterburners and fabric filters relative to the established average temperatures.
      One commenter (IV-D-6) stated that the 25 F operating tolerance is arbitrary and there is no evidence that this will not result in dioxin emissions in excess of standard. They stated that EPA should require worst case performance testing and not permit sources to exceed the control device inlet temperature of the performance test.
      Another commenter (IV-D-17) stated that the language in section 63.1506(g) of the proposed rule to monitor the inlet temperature of fabric filter needs to be rewritten to be more clear.
      Response:  There is evidence to suggest that D/F formation is strongly influenced by temperature in the FF.  There is no assurance that an affected source that meets the standard at one temperature will continue to meet the standard at a higher temperature.  The rule allows a 25 F tolerance in recognition of the potential time lag in temperature sensing and control system response.  Operators are free to conduct performance tests under worst case conditions, e.g., 350 F and then operate 300 F to achieve a 50 F window, or to upgrade temperature control systems to maintain the FF inlet temperature within the 25 F tolerance under all conditions.

      3.2.12 Comment:  One commenter (IV-D-10) stated that the requirement for continuous lime injection for FF will generate excessive quantities of potentially hazardous waste to be accommodated by declining landfill capacity.  They stated that lime precoating on finer mesh polyester bags may be just as effective and that continuous feeding does not ensure continuous injection because feeders become clogged.  Another commenter (IV-D-13) is concerned about the requirement to add lime to baghouse continuously since their current practice is to inject lime at the beginning of 24 hour melting cycle; at the end of the cycle, bags are cleaned and fresh lime is added.  They stated that the pressure drop across filters is monitored and when the pressure reaches a predetermined limit, melting is halted or bags cleaned and new lime is added. The commenter is uncertain as to how to add lime continuously and questioned the need to do so because only a finite amount of lime can be applied to bags and the rest would be wasted.
      Response:  Continuous lime injection is the MACT floor technology upon which the emission limits are based.  The operating requirements in the final rule are tailored to continuous lime injection systems.  Operators may use batch injection or another technology with the approval of the permitting authority, and if they can demonstrate compliance with the emission limits.  Operators may conduct performance tests under intermittent lime addition conditions and maintain intermittent lime addition at performance test conditions when approved in advance by the permitting authority.  The rule includes requirements for determining if continuous lime feeders are clogged and corrective action in the event that they are not operating properly.

      3.2.13 Comment:  One commenter (IV-D-17) stated that the cross reference to emission standards for group 1 furnaces without add-on controls in 63.1506(n)(3) is incorrect; it should be 63.1505(i)(3) rather than (2). One commenter (IV-D-24) pointed out an error in 1506(n)(3); the reference should be to 1505(i)(1) and (3).
      Response:  These references have been corrected in the final rule.

      3.2.14 Comment:  One commenter (IV-D-9) recommended allowing furnace redesign as a compliance alternative for group 1 furnaces.
      Response:  Operators may use any means they choose to comply with the emission limits.  If a successful performance test is conducted without the use of a control device, the source is not required to install a control device.

      3.2.15 Comment:  One commenter (IV-D-31) wanted site-specific monitoring for uncontrolled emission units.

      Response:  A source may develop (with the approval of the permitting authority) alternate monitoring procedures for emission units within a SAPU or affected sources without add-on controls.

      3.2.16 Comment:  Several comments were received on the feed/charge weight requirements.
      1) One commenter (IV-D-17) stated that the requirement for feed/charge weight determinations (63.1506(d)) should be revised to be consistent with the Part 70 operating permit program and recommended language to that effect.
      2) One commenter (IV-D-32) supported the flexibility provided by feed/charge weight options but stated that the facility should also be allowed to substitute production weight for feed weight.  This would cause the denominator for emission rate calculation to be smaller and therefore give a conservative measure of compliance.
      3) One commenter  (IV-D-31) wanted facility-wide charge weight monitoring.
      4) One commenter (IV-D-31) wanted charge weight monitoring frequency to be site-specific.
      Response:  1) Accurate determination of charge weight is required to ensure compliance with production-based standards.  Sources that are unable to meet the charge weight measurement tolerances established in the rule may apply to the permitting authority for approval of alternate monitoring procedures.
      2) Operators are permitted to substitute production rate for charge weight and the final rule states this.
      3) Operators demonstrate compliance for SAPUs based on  performance tests.  Charge weights must be determined on an emission unit basis to ensure that the calculations for SAPU wide emissions are correct.  In addition, flux rate monitoring is based on individual emission unit production rates.  Control devices must be tested under the highest load reasonably anticipated to occur, and if production is shifted from emission unit to emission unit, performance test data would not be valid, therefore this is not allowed.
      4) For batch processes, charge weight must be monitored for each furnace cycle to properly calculate SAPU compliance, and to determine that individual emission units are being operated within established parameters.

      3.2.17 Comment:  Two commenters (IV-D-23, IV-D-32) stated that air breaks in ductwork are needed to achieve cooling of gases upstream of FFs to protect FFs. They recommended deleting proposed section 63.1506(c)(2).
      Response:  The final rule has been clarified to permit air breaks in ductwork for gas cooling.

      3.2.18 Comment:  One commenter (IV-D-17) stated that the wording in Table 1 of section 63.1506 of the proposed rule requiring corrective action when "any" visible emission occurs, effectively prohibits any visible emissions. The commenter recommended corrective action when a 6-minute average opacity reading of greater than or equal to 5 percent is determined via a visible emissions evaluation.
      Response:  The commenter correctly interpreted the rule in that EPA requires corrective action when a visible emission occurs.  This is required in instances when a continuous opacity monitor is not installed and the operating requirement is periodic visual inspection for emissions.  The EPA and industry generally concurred that no visible emissions occur when the control technology is operated properly.

4.  Monitoring And Compliance Requirements

      4.1	Monitoring Requirements

      4.1.1 Comment:  Several comments were received that requested more flexibility in the monitoring requirements aimed at reducing the burden to the industry:
      1)  One commenter stated that the operating and monitoring requirements of §§63.1506 and 63.1510 are too prescriptive and not consistent with preamble statements regarding flexibility. (IV-D-32)
      2)  Several commenters stated that EPA should allow alternative site-specific monitoring and operating plans to improve feasibility and cost effectiveness. (IV-D-9, IV-D-31, IV-D-33, IV-D-35)
      3)  Another commenter stated that separate provisions should be included in each of §§63.1506 and 63.1510 allowing facilities to develop alternative procedures approvable by the applicable permitting agency. (IV-D-32)
      4)  Two commenters claimed the provisions will result in burdensome, labor-intensive requirements without commensurate benefit to the environment. (IV-D-22, IV-D-35)
      5)  Another commenter with a rolling mill facility claimed their plant is operating at demonstrated low emission levels and seeks monitoring plan flexibility to allow their facility to continue in its present mode.  Referring to this plant, another commenter stated that the plant has developed a correlation between opacity and PM which has been used for over a year, in accordance with a regulatory order.  This monitoring has been approved by EPA and the local agency and is federally enforceable. (IV-D-32)
      Response:  The final rule has been written to incorporate more flexibility in the monitoring requirements:

      1), 2), and 3) The final rule includes explicit provisions for obtaining approval to use alternative monitoring procedures and lists the types of information needed in the application.  It includes data or information to justify the request such as technical or economic infeasibility, a description of the proposed alternative monitoring requirements including operating parameters and how the limit for SAPUs (if SAPUs are included in the application) will be calculated, and information as to how the alternative monitoring requirements would provide equivalent or better assurance of compliance with the standards.
      In addition, in response to the numerous comments received regarding the proposed monitoring and operating provisions, the final rule has been written to provide more flexibility to individual facilities in developing their OM&M plans and for approval of site-specific monitoring and operating alternatives, within EPA guidelines, by the permitting authority.  Additional comment responses below discuss some specific changes made in the final rule.
      4) The monitoring requirements are necessary to demonstrate continuous compliance and, as such, are environmentally beneficial.  Most, if not all, of the monitoring data collection or logging can be computerized and, therefore, will not be labor intensive.
      5) Specifically, the final rule allows the owner/operator of a plant to apply to the Administrator for alternative monitoring, if necessary, or document their current procedures in the facility OM&M plan.  The OM&M plan is submitted to the permitting authority for review and approval.  The final rule gives more flexibility, for example, through guidance for scrap inspections (used in operating limits and monitoring) that is less prescriptive and more options for lime injection monitoring.

      4.1.2  Comment:  Several commenters stated that the monitoring frequencies and data quality objectives are too restrictive and specific for application across a diverse industry and bear no relevance to the emission standards or ensuring proper operation of emission controls. (IV-D-9, IV-D-22, IV-D-31, IV-D-35,)  Another commenter agreed with the selection of the monitoring parameters in the proposed rule, but stated that the monitoring intervals are too frequent. (IV-D-8)
      Response:  Monitoring frequency requirements are related to the need for evidence of continuous compliance, and frequent readings are essential to provide the demonstration.  However, the final rule changes the frequency of recording monitored parameter values from that proposed.  For example, the frequency of recording fluxing rates has been reduced by requiring readings only during periods when flux additions are occurring.  Additional options included for monitoring free-flowing lime change those monitoring and frequency requirements and increase the monitoring options.  Furthermore, the provisions for site-specific OM&M plans approved by permitting authorities allow opportunity for adjustment of monitoring, within EPA guidelines, to fit site-specific conditions.  Comments dealing with data-quality objectives for specific monitored parameters are addressed in more detail below.

      4.1.3  Comment:  Several commenters argued that the requirements for accuracy of 1 percent when applied to feed/charge weight and flux injection rates are overly stringent and burdensome and create an unnecessary increment for a violation. (IV-D-1, IV-D-9, IV-D-10, IV-D-11, IV-D-22, IV-D-23, IV-D-27, IV-D-32)
      Response:  The EPA has retained the 1 percent accuracy requirement in the final rule.  However, the EPA recognizes there may be situations in which 1 percent accuracy for feed/charge weight and chlorine flux injection rate is not workable.  An example of this may be operating at a very low flux injection rate.  The final rule has been written to allow the permitting authority to approve alternative accuracy requirements for monitoring equipment, on a site-specific basis, in situations where the 1 percent accuracy requirement is not workable and where the owner/operator provides data/information to substantiate that emission standards will be achieved on a continuous basis.

      4.1.4  Comment:  In comments on accuracy of performance test measurements and feed/charge weight measurements:
      1)  One commenter stated that the EPA reference methods are not better than 10 percent repeatable, so the requirement for 1 percent accuracy in charge weight is arbitrary and unnecessarily burdensome. (IV-D-32)
      2)  Another commenter requested less stringency in the accuracy requirement for the sources whose emissions are well under the emission limit, noting that the expected accuracy of Methods 26A and 5 is 10 percent.  This commenter suggested that the charge weight monitoring be restricted to only those sources having to comply with a lb/ton emission limit. (IV-D-8)
      3)  An additional commenter stated that an aggregate accuracy of 5 percent is more representative of reproducible floor practice. (IV-D-9)
      4)  Another commenter wanted the weight monitoring not to be required for each emission unit, but allowed to be aggregated across emission units. (IV-D-31)
      Response:  The EPA considered the measurement accuracy issue raised by the commenters and addresses their points as follows:
      1), 2), and 3)  Related to test method accuracy, the EPA notes that the variability in the test methods, process, and control equipment is incorporated into the testing results upon which the emission limits are based.  The limits have been established to accommodate that variability.  Given that the emission limits are on a lb-of-emission/ton-of-feed (or charge) basis, it is also in the owner/operators best interest to make an accurate weight determination because inaccurate measurements could cause them to be out of compliance.  As noted in the previous response, the final rule provides additional flexibility with regard to feed/charge measurement in situations where the 1 percent accuracy is not workable.

      4)  Weight monitoring is required because the emission limits are based on lb/ton of feed/charge or product.  Under the site-specific OM&M plans, individual emission units of the same type may have different allowable emission rates based on the presence of add-on control devices, fluxing practice, and feed/charge practices.  The only way to determine compliance is to monitor weights for individual emission units.

      4.1.5  Comment:  One commenter stated that inspection of lime feed systems once per 8-hour shift and more frequently when found to be plugged may be difficult, arguing that visual inspection at silo and bin tops is dangerous.  The commenter suggested alternate language that reduces the required checks from every 4 hours for 3 days, if plugged, to checks for only 2 consecutive 4-hour periods following restoration to free flow.  Another commenter also disagreed with the requirement to inspect every 4 hours for 3 days, even if the problem is corrected earlier.
      Response:  Based on the comments received the final rule has been written to provide other options to demonstrate free-flowing lime.  In addition to the option to perform visual checks to verify free-flowing lime, the owner/operator may use devices such as load cells to demonstrate this via weight changes in lime feed bins, use pressure sensors in pneumatic conveying systems to distinguish low or "no flow" conditions, continuously monitor lime feed rate, use an HCl monitoring device at the fabric filter outlet, or another method subject to approval by the permitting authority.

      4.1.6  Comment:  One commenter requested that lime feeder inspection requirements and corrective action requirements demonstrate compliance and that discovery and correction of a blockage or feeder setting drift not be an automatic violation.  The commenter suggested that the rule be rewritten to require corrective action when necessary and not to make blockage or feeder setting drift a violation.
      Response:  As noted in the response to the previous comment, the final rule provides additional options for monitoring the lime system to maintain free-flowing lime.  One of those options, the HCl monitor, provides a direct indication of continued effective operation of the control system which is the desired goal of any monitoring option selected.  Other options that detect lime feeder blockages are not direct and immediate performance indicators, so the time until remedied is a critical variable.  For this reason, EPA requires maintenance of free flowing lime in the feed hopper or silo at all times.  Blockages that occur as a result of equipment breakage or failure would potentially fall under the malfunction provision, and if determined to be a malfunction, would be covered by the SSM plan and would not be a violation, if corrected in accordance with the SSM plan.  However, continued and frequent blockages indicate a system design and operating problem rather than a malfunction.

      4.1.7  Comment:  Several commenters objected to the proposed regulatory requirements for scrap inspection programs.  They stated that the requirements are too onerous, expensive, complex and overly prescriptive, and further, some provisions are not technically feasible or cannot be reasonably met.  Three of the commenters suggested that the broadly stated scrap inspection requirements provided in the preamble to the proposed rule could be acceptable, and that approval of site-specific plans by the permitting authority would be a more acceptable requirement.  Two commenters also stated that the scrap should not have to be inspected if the necessary control systems are in place.  According to these commenters, inspection is only needed for control by work practices or pollution prevention.  They stated that the EPA needs to be clearer as to which sources are covered; the preamble says all furnaces and the rule says uncontrolled group 1 furnaces.
      Response:  The scrap inspection program requirements apply only to those facilities that elect to use such a program as a monitoring technique to ensure the oil and coatings content of scrap charged to a group 1 furnace stays below levels established during the performance tests.  Such a program could apply to facilities that have only uncontrolled group 1 furnaces, or facilities that have both add-on controlled and uncontrolled group 1 furnaces.
      As a result of the numerous comments received regarding the scrap inspection program elements, the EPA has modified the proposed rule.  The detailed requirements contained in the proposed rule have been deleted and the general scrap inspection guidelines provided in the proposal preamble have been adopted.  This change will provide more flexibility to owner/operators to tailor the program to specific conditions for their facility.  The scrap inspection program, if selected by the facility, will become part of the site-specific OM&M plan.  The specific inspection program elements, which must be consistent with guidance in the rule, will be approvable by the permitting authority as part of the site-specific OM&M plan and will be enforceable under the facility's permit.

      4.1.8 Comment:  One commenter stated that firms would likely need to hire additional staff to process paperwork, especially the monitoring data recorded every 15 minutes.  The commenter argued that these requirements have no corresponding benefit to the environment; requiring a report to document no exceedances is unnecessary when the absence of a report of exceedances should presume compliance. (Institute of Scrap Recyclers)

      Response:  The facilities' burden for processing and reporting results from  monitoring data were included in the impacts estimates reported with the proposal package for this rule.  Recording data every 15 minutes would require few if any additional staff.  Data logging equipment and software automate this process.  Such systems may be set up to sound warning devices when monitored levels approach or exceed the established operating limits.  The requirements to process and report results periodically ensures that some staff are assigned the responsibility to identify problems and take corrective actions when necessary, and that a corporate official is obligated to report the results of these efforts.  The benefit to the environment is the continuous prevention of HAP emissions in excess of established emission limits.

      4.1.9  Comment:  Two commenters wanted to establish parameters for control devices other than baghouses, lime baghouses and afterburners.  Wet scrubbers used in one facility illustrate such a need.  Such alternative monitoring plans could be handled on a site-specific basis subject to permit authority review. (IV-D-31, IV-D-8) Another commenter suggested provisions for and language permitting the use of alternate control devices with site-specific monitoring plans. (IV-D-28)
      Response:	The General Provisions provide for the use of alternatives to monitoring requirements or procedures upon approval by the Administrator (40 CFR 63.8(b)).  Monitoring parameters for scrubbers or other alternative control devices can be established under this provision.  Consistent with the General Provisions, the final rule has been modified to specify some procedural requirements for applying and obtaining approval of alternative monitoring programs.

      4.1.10  Comment:  Two commenters requested that the requirement to calibrate lime injection rate, flux injection rate, and other monitoring instrumentation quarterly should be changed to "in accordance with manufacturer's specifications" throughout the rule.  The EPA requirement may conflict with the manufacturer's recommendation. (IV-D-32, IV-D-8)
      Response:  The final rule has been revised in the appropriate sections to require monitoring equipment calibration in accordance with the manufacturers' recommended schedule or if no schedule is specified at least once every 6-months.  It was not EPA's intention to have the calibration occur less frequently than that recommended by the manufacturers.

      4.1.11  Comment:  One commenter wants to restrict application of the Operation, Maintenance, and Monitoring (OM&M) plan to the control device, not the affected source, and the commenter also wants to exempt uncontrolled sources from the plan. (IV-D-8)

      Response:  Although the add-on air pollution control device is the means by which emission reductions are ensured for those affected sources or secondary aluminum processing unit- emission units vented to such a device, process operating conditions for the attached sources also affect the level of emissions achieved.  It is for this reason that EPA is requiring the establishment of operating limits for process parameters such as flux injection rate.  For uncontrolled emission units that are part of a secondary aluminum processing unit, the level of emissions is directly related to the type and amount of flux used as well as the level of contamination in the scrap fed, in the case of melting furnaces.  It is essential that the OM&M plan document the work practices and pollution prevention measures that will be used to maintain compliance and that these practices and measures then become an enforceable part of the permit.

      4.1.12  Comment:  According to two commenters, by the time the rule is finalized most affected sources will have Part 70 or 71 permits.  These two commenters wanted a requirement that the OM&M plans be available for review not that they be required to submit them as part of the Part 70 or 71 process.  The costs would be burdensome and were not included in the economic analysis. (IV-D-18, IV-D-20)
      Response:  The proposed rule required the OM&M plan to be submitted to the applicable permitting authority as part of the application for a Part 70 or 71 permit.  Based on the comments received and a further review of the proposed requirements the EPA is clarifying the requirements for the OM&M plan.  As the commenters mention, some facilities will already have their permits, so it is not feasible for them to submit the OM&M plan as part of the application process.  Also it was not EPA's intention to have the OM&M plan itself incorporated into the permit, such that it would be necessary to reopen the permit if changes to the OM&M plan are desired.  The permit can incorporate the OM&M plan by reference upon the plan approval by the permitting authority. The OM&M plan would be external to the permit so that a permit revision is not necessary when an OM&M plan change is desired.  For those plants already having permits when the final rule is promulgated, the OM&M plan will be incorporated by reference.

      4.1.13  Comment:  One commenter suggested the requirement for verification (of accuracy in feed measurements) every three months should worded to be either once per quarter, or else within three months of the last verification.  This commenter also suggested changing the requirement to verify weight calibration every three months to a requirement to check it and recalibrate if the error is found to be greater than 1%. (IV-D-20)
      Response:	The EPA has considered this, and other comments related to measurement accuracy for feed/charge.  The final rule has been changed to require verification of the calibration at the frequency recommended by the manufacturer, or if no calibration frequency is specified, at least once every six months.

      4.1.14  Comment:  One commenter wanted solid flux excluded from charge weight. (IV-D-8)

      Response:  Most of the test data that were used as the basis for selection of emission limits for the affected sources and emission units were computed on the basis of exclusion of solid fluxes from the feed/charge weight. Therefore, this definition is modified in the final rule to exclude solid fluxes, except for dross-only furnaces.  The EPA has determined that it is appropriate to continue to include solid fluxes as part of the feed/charge for dross-only furnaces.

      4.1.15  Comment:  One commenter supported the monitoring options provided for fabric filters. (IV-D-11)  Another commenter wanted Method 9 or daily visual inspection added to the monitoring options available for fabric filters (Method 9 is an option for scrap shredders, but not other affected sources or emission units). (IV-D-23)
      Response:	 The EPA proposed the daily use of EPA Method 9 as an alternative means of monitoring compliance for fabric filters and lime-injected fabric filters serving scrap shredders due to the intermittent nature of shredder operations.  The final rule retains the requirement for all affected sources or emission units with fabric filters or lime-injected fabric filters (other than scrap shredders) to install, operate, and maintain a bag leak detector system, or install and operate a continuous opacity monitoring system to provide evidence of continuing compliance.

      4.1.16  Comment:  One commenter suggested alternative wording for calibration of the bag leak detection system at 63.1510(f)(1)(ix) of the proposed rule to clarify the intent. (IV-D-17)  Another commenter supported the option to use bag leak detectors that operate on principles other than triboelectric.  This commenter recommended that recording milliamp current be allowed as an alternative to output voltage.(IV-D-11)  One commenter requested clarification that non-triboelectric bag leak detectors can be used.  Also the commenter questioned whether the EPA guidance is intended to apply only to triboelectric detectors.  The commenter stated that a clarification is needed as to whether record keeping and response tests specified in the guidance are required by the rule and whether recommended and suggested procedures are required by the rule.  Details of what is intended to be mandatory and enforceable should be provided. (IV-D-28)
      Response:  The guidance referenced in the proposed and final rule is intended to apply only to triboelectric detectors.  The record keeping and response tests specified in the guidance are required by the rule.  The recommended procedures and suggested procedures are also required by the rule.  Some flexibility is provided in the guidance, so an owner/operator can select an option and follow that option.
      However, bag leak detection systems based on triboelectric principle are not the only type that can be used.  For other types of bag leak detection systems, the manufacturer's recommendations should be followed.

      With respect to the requirement to monitor output voltage from the system that was in the proposed rule at 63.1510(f)(1)(v), the intent was to monitor the electrical signal from the triboelectric sensor that indicates relative PM loadings.  If the bag leak detection system installed uses current or some other type signal instead of voltage to provide that relative PM loading, then current or the other signal should be monitored instead of voltage.

      4.1.17  Comment:  Two commenters stated that PS-2 was established for SO2 and NOx monitoring systems, not temperature monitoring and PS-2 is therefore not applicable.  One commenter gave six cites for requirements that do not apply or work, stating that existing equipment is not suitable for temperature traversing because it is not equipped with ports for that purpose.  The other commenter also stated that adding sampling ports would decrease structural integrity of the system and potentially expose workers to high temperatures. The latter commenter also requested EPA to modify the temperature monitoring device provisions that call for use of a NIST reference method (63.1510(h)(2)(v) of the proposed rule) to clarify that what is being required is the use of a calibration standard, not a reference test method such as those in Appendix A, part 60. (IV-D-23, IV-D-17)  Another commenter stated that the relative accuracy requirements are unnecessary for temperature monitoring. (IV-D-11)
      Response:	 The EPA agrees that Performance Specification-2 is not appropriate for application to temperature measurement. Based on the other comments received, the requirements for the temperature monitoring device for affected sources using an afterburner or fabric filter have been revised.  The final rule requires that the recorder response range include zero and 1.5 times the average temperatures established as the monitoring parameter and that the calibration method must be a National Institute of Standards and Technology calibrated reference thermocouple-potentiometer system or alternate reference, subject to approval by the Administrator.

      4.1.18  Comment:  One commenter stated that the proposed rule included two sections 1510(g)(2). (IV-D-20)
      Response:	 This assertion is incorrect, there was only one section 1510(g)(2) in the proposed rule.

      4.1.19  Comment:  Two commenters supported options for monitoring injection weight, and maintaining and recording injection rate. (IV-D-23, IV-D-11)
      Response:	The EPA acknowledges these comments in support of the rule provisions and notes that the final rule also includes a provision for obtaining approval of alternate monitoring procedures.

      4.1.20  Comment:  One commenter stated that inspection of lime feed systems once per 8 hour shift and more frequently when found to be plugged may be difficult, arguing that visual inspection at silo and bin tops is dangerous.  The commenter suggested alternate language that reduces the required checks every 4 hours for 3 days if plugged to checks for only 2 consecutive 4-hour periods when restored to free flow.  Another commenter also disagreed with the requirement to inspect every 4 hours for 3 days, even if the problem is corrected earlier (IV-D-23, IV-D-11)
      Response:  Based on the comments received, the final rule has been modified to provide other options to demonstrate free-flowing lime.  In addition to the option to perform visual checks to verify free-flowing lime, the owner/operator may use devices such as load cells to demonstrate this via weight changes in lime feed bins, use pressure sensors in pneumatic conveying systems to distinguish low or "no flow" conditions, continuously monitor lime feed rate, use an HCl monitoring device at the fabric filter outlet, or another method subject to approval by the permitting authority.

      4.1.21  Comment:  One commenter requested that lime feeder inspection requirements and corrective action requirements demonstrate compliance and that discovery and correction of a blockage or feeder setting drift not be an automatic violation.  The commenter suggested that the rule be rewritten to require corrective action when necessary, not to make blockage or feeder setting drift a violation.
(IV-D-28)
      Response: As noted in the response to the previous comment, the final rule provides additional options for monitoring the lime system to maintain free-flowing lime.  One of those options, the HCl monitor, provides a direct indication of continued effective operation of the control system which is the desired goal of any monitoring option selected.  Other options that detect lime feeder blockages are not direct and immediate performance indicators, so the time until remedied is a critical variable.  For this reason EPA requires maintenance of free flowing lime in the feed hopper or silo at all times.  Blockages that occur as a result of equipment breakage or failure would potentially fall under the malfunction provision, and if determined to be a malfunction, would be covered by the Startup, Shutdown, and Malfunction (SSM) plan and not a violation, if corrected in accordance with the SSM plan.  However, continued and frequent blockage indicates a system design or operating problem rather than a malfunction.

      4.1.22  Comment:  Several commenters suggested alternatives to the manual inspection of lime feed hoppers.  One commenter states that a facility has installed devices that continuously monitor lime feed rate. (IV-D-17) Another commenter states that manual inspection should be changed to allow computerized weight loss monitoring and demonstration of reliability of alternatives as part of development of the OM&M plan. (IV-D-32)   A third commenter recommends that lime feed pneumatic conveyor blower pressure be monitored to determine if lime is free flowing and that a sensor be installed that activates an alarm if no lime feed is detected. (IV-D-11)
      Response:	 Based on the comments received, the final rule has been modified to provide other options to demonstrate free-flowing lime.  In addition to the option to perform visual checks to verify free-flowing lime, the owner/operator may use devices such as load cells to demonstrate this via weight changes in lime feed bins, use pressure sensors in pneumatic conveying systems to distinguish low or "no flow" conditions, continuously monitor lime feed rate, use an HCl monitoring device at the fabric filter outlet, or another method subject to approval by the permitting authority.

      4.1.23  Comment:  One commenter agreed with need to monitor chlorine usage on in-line fluxers and group 1 furnaces without add-on controls and to maintain rate at or below the average measured during the performance test. (IV-D-11)
      Response:  The EPA acknowledges support for those provisions of the rule.

      4.1.24  Comment:  Several commenters claimed continuous flux measurements are not needed since much of the time during furnace cycles there is no fluxing.  The requirement for continuous measurement and recording 15-minute blocks is an undue burden when applied across entire industry.  Having data in 15-minute blocks does not necessarily yield accurate results.  Many facilities only flux 10 to 30 minutes out of a 5-7 hour cycle and so would be recording zero values for 97% of the operating time.  Likewise solid flux additions and other fluxing may occur in batches.  The commenters stated that the requirement to continuously measure and record is unreasonable and provides no environmental benefit. (IV-D-23, IV-D-22, IV-D-17, IV-D-11, IV-D-32) Another commenter stated that they will have to measure chlorine before dilution to meet this requirement, and thus pipe pure chlorine, rather than a 12% mixture, through the plant to each furnace which they view as a safety problem. (IV-D-8)
      Response:	 The EPA has reviewed the flux injection rate monitoring requirements and, based on comments received, modified the requirements in the final rule.  As noted by the commenters many furnaces do inject flux for only short time periods within a furnace cycle and others add solid flux in batches.  The monitoring provisions have been modified to require recording flux injection rate in 15-minute blocks only during periods when fluxing is occurring.

      The EPA's intent is to achieve high accuracy in the measurement of reactive flux usage. The latter commenter mixes flux gases at a central location prior to distribution through the plant to eliminate the presence of pure chlorine gas in work areas.  The weight of reactive flux component in the diluted mixture must be measured to 1 percent accuracy, and the quantity of mixture delivered to each emission unit must also be measured to yield an accurate quantitative measurement of reactive component used per emission unit during the monitoring period.  The final rule does not preclude the use of central mixing stations for reactive flux gases provided that the amount of reactive flux component delivered to each emission unit is determined within 1 percent accuracy.  As described in the response to Comment 4.1.3,  the final rule does provide for the permitting authority to approve alternative monitoring accuracy requirements on a site-specific basis when 1 percent may not be workable.

      4.1.25  Comment:  Several commenters suggested alternatives to the flux monitoring requirements.  One commenter suggested measuring flux cylinder weights before and after casting operations for monitoring for in-line fluxers.(IV-D-23)  Two commenters stated the regulation should provide an option for a site-specific monitoring scheme better suited to each operation. (IV-D-22, IV-D-8)   Another commenter urged EPA to provide monitoring flexibility in the form of alternative monitoring techniques. (IV-D-32)   One commenter suggested an HCl monitor in the waste gas stream to automatically control the baghouse lime injection system should be allowed in lieu of monitoring chlorine flux input. (IV-D-11)   EPA should allow proper operation of pollution control systems to replace continuous weighing of flux salts. (IV-D-11) Other commenters requested SAPU bubble monitoring of flux (no monitoring for individual emission units) (IV-D-1, IV-D-32).  One commenter also wanted to drop the fluxing schedule requirements and substitute a monthly mass input to the SAPU. (IV-D-8)
      Response:	 The EPA recognizes the wide variety of fluxing practices among facilities and within facilities for different affected sources or emission units.  The purpose of requiring monitoring of fluxing rates and flux consumption is to provide continuous verification that the practices (as monitored by selected parameter values) do not exceed those practices in use during the performance tests (that could cause emissions to exceed the levels achieved in the compliance demonstration).  The alternate monitoring practice, used by one commenter, of operating a HCl monitor to control the amount of lime injected to the fabric filter control system is an acceptable alternative to flux injection rate monitoring for controlled sources.  This is not an option for uncontrolled affected sources or emission units.  The final rule has been modified to include the option for a HCl monitoring system that controls the lime injection feed rate.

      The use of bubble monitoring of flux is not a satisfactory alternative for SAPU that include both controlled and uncontrolled emission units because it is necessary to distinguish between consumption in controlled and uncontrolled units.  Even for controlled units that are served by different control systems, it is necessary to monitor rates and consumption of flux in relation to rates and consumption of lime so as to monitor the performance of the separate control systems.  For systems in which all emission units are connected to the same control system, bubbled flux monitoring across all units is acceptable provided HCl concentrations are monitored and demonstrate that the allowable HCl emission rate is not exceeded.  	Extending the flux monitoring period to a monthly basis permits daily or cycle-to-cycle variations in the relative usage of lime and flux that will not necessarily coincide.  This will lead to increased emissions as compared to those measured during performance tests and thus is not acceptable.
      The final rule has been modified to allow bubbled flux monitoring for all emission units connected to the same HCl emissions control system if monitoring control system outlet waste gas HCl concentrations to demonstrate that the allowable HCl emission rate is not exceeded.  The final rule retains the requirements for monitoring over the operating cycle or period of the performance test.

      4.1.26  Comment:  One commenter disagreed with the record keeping and compliance certification requirements, stating they are unnecessary.  In-line refining of molten aluminum for product quality purposes without use of reactive flux should not be subject to rule. (IV-D-17)  Another commenter stated that the requirement to identify fluxing agents on a cycle-by-cycle basis is unnecessary since in-line fluxers not using reactive fluxes use the same flux every day. The certification requirement of 63.1510(m)(2) of the proposed rule is sufficient, (m)(1) should be deleted. (IV-D-32) A third commenter wanted a monitoring exemption for in-line fluxers that do not use reactive flux. (IV-D-31)
      Response:  The EPA agrees that in-line fluxers that do not use reactive flux can be subject to less rigorous record keeping and compliance certification requirements than those using reactive fluxes.  The final rule has been revised to require that owner/operators of in-line fluxers that don't use reactive fluxes keep a record of the flux materials used (does not have to be on a cycle-by-cycle basis) and certify every six months that only those materials were processed in the fluxer.

      4.1.27  Comment:  One commenter suggested adding the word sidewell between "Group 1" and "furnace" in 63.1510(n) of the proposed rule. (IV-D-32)   Another commenter asked for clarifications of which requirements in 1510(n), only apply to sidewell furnaces.   In 1510(n)(1), the latter commenter suggested that the operator record whether or not the level of molten metal was above the top of the arch and adding a requirement for corrective action for the situation if the level is not. (IV-D-20)
      Response:	 At present all the provisions of 63.1510(n) deal with sidewell furnaces, so the commenter's suggested addition to clarify this is appropriate.  The final rule has been changed to clarify this point.  The rule as proposed does have a corrective action requirement in 63.1506(q), however, it may not be clear that the operating requirement for metal level in sidewell furnaces is covered.  The final rule states that maintenance of the metal level above the top of the arch is an operating requirement.  Failure to maintain that level is a violation.

      4.1.28  Comment:  One commenter interpreted 63.1510(o) of the proposed rule to allow the use of COMs as approved alternatives to scrap inspection.  The requirement in 63.1510(o)(ii) for a relationship between parameters and emissions should allow for the use of minimum or maximum values below which or above which compliance is assured.  For example, if flux usage is less than the emission limit that is sufficient to demonstrate compliance. (IV-D-32)  Another commenter suggested that one worst case scenario (rather than multiple parametric tests) as required in 63.1510(o)(1)(ii) (as well as in 63.1505(l) for SAPU's) is adequate to establish operating limits for SAPUs. (IV-D-8)
      Response:  The commenter's interpretation of 63.1510(o) relative to Group 1 furnaces without add-on control devices is not correct.  A COM cannot be used as an alternative to scrap inspection.  COMs do not provide an indication of D/F, HCl, or Cl2 emissions.
      Testing of maximum or worst case flux addition values to establish operating limits for SAPU is acceptable.  As suggested by the commenter, if flux usage is monitored and it is less than the emission limit for the affected source or emission unit, this would demonstrate compliance.

      4.1.29  Comment:  One commenter wanted the deadline for submittal of the site-specific monitoring plan moved to six months before the compliance date, as opposed to six months before the performance test.(IV-D-31)
      Response:	 After consideration the EPA agrees that is appropriate to change the deadline for submittal of the site-specific monitoring plan to at least six months prior to the compliance date.  That change has been made in the final rule.

      4.1.30  Comment:  Several commenters objected to the proposed regulatory requirements for scrap inspection programs:  	1) Several stated that the requirements are too onerous, expensive, complex and overly prescriptive, and further, as provided in some examples, some provisions are not technically feasible or not reasonably met. (IV-D-23, IV-D-22 IV-D-17, IV-D-32, IV-D-18, IV-D-20)
      2) One commenter stated that the procedures for inspector training, certification and program validation and verification will place large burden on one of their facilities to maintain on-site inspection program.  The commenter wanted flexibility of alternate inspector training and a less stringent inspection program with review and approval by the permit authority. (IV-D-11)
      3) Three of the commenters suggested that the broadly stated scrap inspection requirements provided in the preamble could be acceptable and that approval of site-specific plans by the permitting authority would be a more acceptable requirement.
      4) Two commenters also stated that scrap should not have to be inspected if necessary controls are in place.  Inspection is only needed for control by work practices or pollution prevention.  They stated that EPA needs to be clearer as to which sources are covered, the preamble says all furnaces and the rule says uncontrolled group 1 furnaces. (IV-D-18, IV-D-20)
      Response:	The requirement for a scrap inspection program is only intended to apply to those facilities that have group 1 furnaces without add-on control devices (including those that are part of a SAPU).  For those facilities that have both add-on controlled and uncontrolled group 1 furnaces, the scrap inspection requirements would apply only to the materials charged to the uncontrolled units.
      As a result of the numerous comments received regarding the scrap inspection program elements, the EPA has modified the final rule to delete the detailed requirements and adopt the general scrap inspection guidance as presented in the proposal preamble.  The scrap inspection program, if selected by the facility, will remain part of the site-specific monitoring plan.  The specific inspection program elements (which must be consistent with guidance in the regulation) will be approvable by the permitting authority as part of the site-specific monitoring plan and will be enforceable under the permit.

      4.1.31  Comment:  One commenter stated that the rule should clarify that it is the responsibility of the source to demonstrate that scrap inspection program meets intent of rule, including use of worst case emission testing, verification sampling of scrap, and enforceable contractual arrangements with offsite entities.  The commenter cited other inspection programs as precedents. (IV-D-9)
      Response:	See the response above.

      4.1.32  Comment: One commenter supported an alternative scrap contamination determination by calculation procedure. (IV-D-11) Another commenter supported simplified scrap inspection procedures for furnaces dedicated to one type of scrap. (IV-D-8)

      Response: In addition to the changes to scrap inspection procedures described in the previous responses, the final rule contains a calculation method for scrap contamination monitoring for group 1 furnaces without add-on control devices that may be appropriate for a furnace dedicated to one type of scrap.

      4.1.33  Comment: In 63.1510(p) of the proposed rule, one commenter wants the term "acceptable scrap" to be defined in the scrap inspection program (as scrap that will not cause excess emissions, for example). (IV-D-20)
      Response:	 As noted in the responses to previous comments, the EPA has substantially revised the requirements for scrap inspection programs.  The EPA has clarified its intent in the final rule by deleting the term "acceptable scrap." which appeared in several places.  The intent in using the term was to describe scrap that meets site-specific acceptance criteria under an approved scrap inspection program and, that when used, will not cause the affected source to exceed the emission limits.

      4.1.34  Comment:  Section 63.1510(q)(2) of the proposed rule dealing with scrap contamination level by calculation, limits charges to having the same composition as in the performance test which a commenter claimed is impossible.  The commenter claimed they should be allowed to use a reasonable worst case in the performance test and stay below that oil and coating content for ongoing compliance. (IV-D-32)
            Response:  The language in the final rule has been modified to explain that "same composition" means oil and coatings content equal to or less than that of the scrap used during the successful performance test.

      4.1.35  Comment:  One commenter stated that the scrap inspection requirements do not provide for the use of a limited amount of coated scrap that could be charged under the emission limit provisions for a SAPU.  That scrap for an individual furnace might have the potential for emissions that exceed an individual furnace limit, but be acceptable when the unit is part of the SAPU. (IV-D-11)
      Response:  Under the scrap inspection requirements and site-specific monitoring plan requirements for a SAPU, the testing program can be used to establish an emission rate for the furnace operating conditions associated with the consumption of a limited amount of coated scrap.  When an emission unit is operated in such a manner, the emission rate associated with that condition would be the rate used to compute the 24-hour emissions for that unit as part of the SAPU emissions calculations for each pollutant.  However, the furnace charge cannot be more contaminated than what was used in the performance test for that furnace.

      4.1.36  Comment:  One commenter states that the dates and provisions of the Site-Specific Test plan (SST), Secondary Aluminum Processing Unit (SAPU) emission plan, Operation, Maintenance and Monitoring plan (OM&M)  Startup, Shutdown, and Malfunction (SSM) plan are too complex and not consistent with each other.  The commenter requests that EPA combine the SAPU emission plan and OM&M into one plan, and fix the dates references. (IV-D-23)  Another commenter requests the requirements be reviewed and simplified to eliminate duplication and reduce the burden to industry. (IV-D-22)  A third commenter suggests a single compliance plan instead of a site specific test plan, a notification of compliance, and an OM&M plan. (IV-D-8)
      Response:	In response to numerous comments related to the submission dates for each of the plans and some apparent confusion regarding the purpose of each, the final rule has been revised to clarify the submission dates and reduce the complexity of the requirements.  All the dates by which the various plans must be submitted are now related to the compliance date which is defined in the final rule as not later than 3 years after the promulgation date for existing units, or upon startup for new units.
      The Startup, Shutdown, and Malfunction (SSM) plan requirements are provided in the General Provisions (40CFR 63.6(e)(3) and have not been changed.  The plan must be developed by the owner/operator by the source's compliance date for the relevant standard.
      The Operating, Maintenance, and Monitoring (OM&M) plan, which includes the site-specific monitoring plan for uncontrolled units, if any are present at the facility, must be submitted no later than 6 months prior to the compliance date or the date by which the facility intends to comply, whichever is sooner.  Those facilities with a SAPU are also required to submit the site-specific SAPU emission plan showing the calculation of the SAPU emission limits, explaining how SAPU emission limits will be achieved, presenting the test plan for performance tests, and other required elements no later than 6 months prior to the compliance date or the date by which the facility intends to comply, whichever is sooner.

  	4.1.37  Comment:  One commenter is concerned with the stipulations of 63.1505(k) that require complying with all requirements of the SAPU emission plan plus all the requirements for each individual emission unit in the SAPU.  The commenter wants to negotiate with the permitting agency for collection of needed data for the site-specific monitoring plan and the SAPU emissions plan to demonstrate compliance.  The commenter does not want to collect monitoring data for each and every emission unit within the SAPU, especially for multiple units connected to a common control device.  The commenter suggests alternate language for 63.1505(k)(5) that requires compliance with the requirements of an approved site-specific SAPU emission plan and, if applicable, a site-specific monitoring plan (under the OM&M plan) without having to do it for each individual emission unit. (IV-D-32)

      Response:	 To simplify the compliance process, the requirement for a separate site-specific emissions plan contained in the proposed rule at 63.1505(k) has been removed from the final rule.  The elements of data and information required for submittal to the permitting authority in this plan under the proposed rule have been incorporated into the OM&M plan in the final rule as described at 63.1510(s).  Across the industry affected by these rules there will be significant variations between facilities in terms of combinations of controlled and uncontrolled emission units and control systems.  In view of this fact, the commenter's request to negotiate with the permitting agency for collection of data for the site-specific monitoring plan (and previous emission plan data) under the OM&M plan is reasonable and allowed under the final rule.  The Agency has revised the final rule and provided some additional guidance to assist the owner/operator and permitting authorities in this matter.
      For controlled and uncontrolled emission units it is necessary to monitor the individual units with respect to charge weight and flux consumption.  The charge weight is essential to the calculation of allowable emissions for a SAPU, and the flux usage must be maintained at or below the values at which the individual units were tested when operating at the defined worst case conditions during the compliance test.  The need for these data is present even if emission units are connected to a common control device.  Just as for a system that controls an individual affected source or emission unit, the lime injection in a system that provides cocontrol must be coordinated with emission unit operations to maintain sufficient lime availability to remove HCl, Cl2, and HF emissions.  Solid reactive flux usage must also be considered in regard to maintaining adequate lime availability.

      4.1.38  Comment:  One commenter wanted clarification that SSM plans are not part of the operating permit. They requested a 30 day deadline for plan approval by EPA, with unreviewed plans considered approved by default. (IV-D-8)
      Response:	The General Provisions (40CFR 63.6(e)(3) direct that the SSM plan be incorporated by reference into the source's Title V permit.  With regard to the issue of approval within 30 days, owner/operators of potentially affected existing sources will have up to 3 years from the promulgation date during which they can prepare and submit the SSM plan for approval. They need to work with the permitting authority to develop a workable plan sufficiently far in advance that approval within 30 days is not necessary.  Unreviewed plans cannot be considered approved by default.

      4.1.39  Comment:  Two commenters stated that the SSM plan should apply only to units with control devices as is the case in the Printing and Publishing MACT. (IV-D-23, IV-D-8)

      Response:	 While the add-on air pollution control devices play the primary role in emission control, variation in the process operations generating the waste gas stream and pollutants affect the emissions as well.  Further, these standards anticipate the presence of emission units using pollution prevention approaches as part of secondary aluminum processing units in many facilities.  These emission units and the associated work practices and pollution prevention measures are the means by which emissions are limited in the SAPU.  For these reasons, and consistent with the General Provisions, all affected sources and emission units must be included in the SSM plan.

      4.1.40  Comment:  One commenter suggested that EPA allow facilities to establish alternative site-specific OM&M plans subject to permit authority review and approval.  These alternative plans would include monitoring provisions different from those in the proposed rule, and reflect changes needed to deal with difficulties specific facilities would encounter in adopting the EPA proposed monitoring provisions. (IV-D-11)
      Response:	 All OM&M plans submitted will be site-specific by definition.  As noted in comment responses above, changes have been made in the final rule to provide more flexibility in monitoring the quantity and accuracy of feed/charge weight, flux usage, lime addition, and scrap inspection.  If an owner/operator wants to use alternative monitoring schemes different than those described as acceptable in the final rule, the procedure to gain approval is to submit a request and obtain approval of the alternative scheme from the Administrator.  The final rule provides the requirements for obtaining approval in 63.1510(w).

      4.1.41  Comment:  Two commenters did not want the OM&M and SAPU emissions plan incorporated in Title V permit because it will make all operating, maintenance, and monitoring procedures enforceable permit conditions.  The commenters stated that it will also be too difficult to make minor changes to their operations without amending the permit which could cause delays for weeks or months. (IV-D-23, IV-D-8)  Another commenter also disagreed with the requirement to have the OM&M plan be part of the Part 70 and 71 permit.  They stated that the site-specific monitoring plan should be developed for and approved by the applicable permitting authority. (IV-D-17)

      Response:  The proposed rule required the OM&M plan to be submitted to the applicable permitting authority as part of the application for a Part 70 or 71 permit.  Based on the comments received and a further review of the proposed requirements, the EPA is clarifying the requirements for the OM&M plan.  It was not EPA's intention to have the OM&M plan itself be incorporated into the permit, such that it would be necessary to reopen the permit if changes to the OM&M plan are desired.  The OM&M plan is to be incorporated into the permit by reference so that it is not necessary to revise the permit when a change in the OM&M plan is desired.  For those facilities that already have a Title V permit when the final rule is promulgated, the OM&M plan will be incorporated by reference.  The OM&M plan requirements become enforceable under the permit upon approval by the permitting authority.
      If an owner/operator wants to revise the ranges or limits established for the operating standards, they must:
      (1)  Submit a request to and obtain approval from the permitting authority to conduct a performance test to revise the operating requirement ranges or limits.
      (2)  After receiving approval from the permitting authority, conduct a performance test to demonstrate that compliance with the emissions standards can be achieved at the revised operating conditions.
      (3)  Submit the performance test results and the revised OM&M plan to the permitting authority for approval.
      (4)  Pending Administrator approval of the revised OM&M plan, the owner/operator must comply with the provisions of the approved plan.
      If the owner/operator is revising an aspect of the plan that does not require an additional performance test, for example, maintenance procedures, they must submit only a final plan to the permitting authority for approval.  Pending the Administrator's approval of the changes, they must comply with the provisions of their approved plan.

      4.1.42  Comment:  Two commenters agreed with EPA and support no monitoring or performance testing provisions for group 2 furnaces. (IV-D-23, IV-D-32)  One of the commenters urged EPA to include external preconsumer runaround scrap in the definition of clean charge.  The commenter claimed this material, often returned from their customers who do not have melting capability, is as clean and predictable as internal runaround. (IV-D-32)
      Response:  The EPA acknowledges the support for the decision not to require monitoring and performance testing for group 2 furnaces.  For a discussion of EPA's consideration of a revision to the definition of "clean charge," see the response to comment 2.1.

      4.1.43  Comment:  Identification of all charge materials in 63.1510(r)(1) of the proposed rule is unnecessary according to two commenters.  Some group 2 melters are used in similar service day after day, and cycle after cycle.  Only monitoring sufficient to supply the certification in 63.1510(r)2 of the proposed rule should be required. (IV-D-32, IV-D-8)

      Response:  The EPA agrees that in such situations it is not necessary to keep cycle-by-cycle records for Group 2 furnaces.  The owner/operator must record all the materials charged to the furnace that make it a Group 2 furnace.  Then, the six-month certification of compliance must contain the information specified in 63.1516(b)(2)(v) of the proposed rule and certify that only the materials they recorded as charged to the furnace were used during that 6-month period.

      4.1.44  Comment:  Another commenter opposed the requirement to record charge and flux materials, unless those materials deviate from the OM&M plan.(IV-D-31)
      Response:  Records of charge and flux materials used in the SAPU are necessary to demonstrate continuous compliance with the emission and operating limits.  Such monitoring observations that show deviations from the ranges or limits established during the initial compliance or performance test are violations of the standard unless caused by events covered by the SSM plan.

      4.1.45  Comment:  In 63.1510(s)(2) of the proposed rule referring to calculation of 3-day, 24-hour rolling average emissions, one commenter stated the words "most recent" should be added when referring to the performance test because tests are conducted every 5 years. (IV-D-20)
      Response:	The commenter was referring to using the results from the most recent performance test in the calculations to monitor compliance.  However, the emission factors established for each affected source or emission unit that is part of a SAPU can only be changed by revising the site-specific OM&M plan (the portion required by 63.1510(s)) per the procedures described in a comment response above under Title V permit comments.  The most recent performance test may or may not be the basis for the currently approved site-specific OM&M plan incorporated in the permit.  Only if the most recent performance test is the basis for the approved OM&M plan can those results be used to calculate the 3-day, 24-hour rolling average emissions under 63.1510(t).

      4.1.46  Comment:  Another commenter wants the instructions for calculating and recording the average emissions based on up to a 30-day average and a 30-day SAPU compliance period. (IV-D-31)
      Response:  Data used to establish the emission limits and operating requirements were based on source tests conducted over relatively short durations.  The test periods required for initial compliance determinations are based on full process operating cycles or 24-hour periods, whichever is less.  For this reason, the final rule retains the requirement to demonstrate compliance on a 3-day 24 hour rolling average basis.  Sufficient data to establish lower 30-day emission limits and monitoring parameters are not available.

      4.1.47  Comment:  Several commenters wanted an alternative to, or believe that EPA did not intend to require, multiple testing over different furnace operating (range of charge/flux) conditions.  One commenter wanted to test under worst case scenario rather than across range of variables (uncontrolled units) as required in 63.1510(o) and 63.1505(l) of the proposed rule.  The commenter gave examples of situations where it would be appropriate and estimates of associated cost savings. The commenter suggested language allowing a permitting authority to approve a test plan if judged to contain sufficient provisions to ensure compliance. (IV-D-23)   Another commenter wanted an alternative to correlations between measured emissions and parameters to be monitored.  For example a minimum or maximum parameter value under which emissions may be less than the limit, i.e., flux usage is less than the limit therefore the limit will not be exceeded. (IV-D-32) Several other commenters stated that a defined worst case condition test will often be adequate to set upper limits on flux use and charge material.  Such an approach should be allowed if approved by the permitting authority. (IV-D-17, IV-D-22, IV-D-11)
      Response:	The purpose of requiring tests over a range of different furnace operating conditions is to show that the selected monitoring parameters are valid indicators of relative emission levels over the range of furnace operating conditions for uncontrolled furnaces.  Testing at maximum or worst case charge/flux addition values to establish operating limits for emission units in a SAPU is acceptable provided that the owner/operator can show the tested cases produce maximum emissions for all regulated pollutants.  However, the measured value of emissions for that maximum case is the level of emissions that must be used in the 24-hour average emission calculations for that unit within a SAPU.  Also, to be in compliance after the compliance date, the flux rate used in the each emission unit must be equal to or less than the amount used during the maximum or worst case test, and the charge materials must be of equal or lower oils and coatings content than the charge materials used during the maximum or worst case test.
      There are some cases in which it may not be possible to establish that a particular test represents a maximum or worst case scenario.  For example, it may not possible to show that a particular combination of oil and coating scrap contamination is worse than another combination without actually performing a test under both conditions.
      As suggested by the commenter, if flux usage is monitored and it is less than the emission limit for the affected source or emission unit, this would demonstrate compliance with the HCl limit.

      4.1.48  Comment:  A commenter believes that the language of the proposed rule requires all operators of secondary aluminum processing units to develop a correlation between emissions and monitored parameters, and that it is not clear that this correlation is only required for uncontrolled Group 1 furnaces.  The commenter requests explicit language that parameter/emission correlations are necessary only when used to demonstrate compliance with the standard. (IV-D-28)

      Response:  The proposed rule at 63.1510(o)(1)(ii) required that the owner/operator of a SAPU show a relationship between emissions and monitoring parameters over the entire range of charge and flux materials processed in the furnace (emission unit).  Also, the proposed rule at 63.1505(l)(2)(vii) required that the site-specific secondary aluminum processing unit emissions plan include a correlation of measured emissions with the selected process or operating parameter to be monitored, as part of the application for an operating permit.  The final rule has been revised to eliminate the requirement for such a correlation.  The Agency has concluded that it will be sufficient to identify maximum or worst case charge and flux conditions under which tests are performed to establish the monitoring parameter values or ranges.  As noted above in a previous comment response, in some situations it may be necessary to perform tests at several conditions to establish which of the conditions are representative of maximum or worst case conditions for an emission unit.

      4.1.49  Comment:  One commenter supported a scaled down monitoring program with reduced monitoring requirements for those units operating at half (for example) the federal emission limitation to provide an incentive for applying controls and operating practices that exceed the MACT floor. (IV-D-22)
      Response:  Measurements that demonstrate operation at low emission rates are short-term indicators of performance.  Process operations vary with time and cannot be relied upon to remain constant.  For this reason the EPA has retained the basic monitoring requirements for all units regardless of the emission levels achieved in relation to the emission limits.

      4.1.50  Comment:  One commenter requested clarification of what is meant by "relative accuracy" in Section 63.1510 of the proposed rule.  When used in conjunction with continuous monitoring systems there are usually set protocols giving procedures and equations to determine relative accuracy. (IV-D-20)
      Response:  This comment refers to requirements in the proposed rule for temperature monitoring devices at fabric filter inlets.  That section has been revised in the final rule to delete the relative accuracy requirement.  The language has been revised to only require that 1) the recorder response range must include zero and 1.5 times the average temperature established according to the requirements in §63.1512(n) for affected sources or emission units using fabric filters for D/F or HCl control, and 2) the reference method must be a National Institute of Standards and Technology calibrated reference thermocouple-potentiometer system or alternate reference, subject to approval by the Administrator.

4.2  Performance Testing and Compliance

      4.2.1  Comment:  Commenters wanted the compliance date to be 3 years after promulgation rather than "on or after the date of the initial performance test."  (IV-D-8, IV-D-22, IV-D-23) They argued that:
      1) Carrying out performance tests prior to the end of 3 years is essential to completing the monumental job; but they do not like having to comply "on and after the date of the initial performance test" which could be the emission test program for the SAPU.
      2) The submittal deadlines for the OM&M plan, the SAPU emission plan, and the site-specific test plan are inconsistent with each other; they wanted EPA to remove all the interim compliance requirements to give the necessary flexibility to evaluate and agree with the permitting agency on compliance requirements before the 3-year deadline.
      Response:  A facility must be in compliance on and after the date of the initial performance test.  The date of that initial performance test, for existing sources, may be up to 3 years after the promulgation date of the standard.  For existing SAPUs, the initial performance test is considered to be the date of approval of the OM&M plan by the permitting authority.
      In response to the comments regarding the inconsistent plan requirements and dates for submittal, the EPA has revised and clarified those requirements.  The final rule requires the owner/operator of a SAPU to perform tests that will define the operating modes of the controlled and uncontrolled emission units within the SAPU, and to define which parameters to monitor to demonstrate continuous compliance.  These same tests can be used to measure the emission rates from the affected sources and emission units for performance test purposes.  A site-specific test plan for this program must be submitted to the permitting authority for review and approval before the tests are conducted.  The plan must identify the parameters to be monitored during the tests, the test methods to be used, the units to be tested, and planned operating modes for each unit during the tests.  After the test plan has been approved by the permitting authority, the owner/operator is required to notify the Administrator of the test dates.

      The results from this test program, including the emission rates measured, values of parameters monitored, monitoring parameters selected by the owner/operator for compliance demonstration, and values of the parameters to be used as operating limits must be submitted to the permitting authority for review and approval.  As a result of the review, the permitting authority may request changes to selected monitoring parameters or values of the parameters used for compliance demonstration if it is determined the parameters or values do not provide an adequate means of demonstrating continuous compliance.  When all of these elements are approved by the permitting authority, the owner/operator prepares an OM&M plan using the approved monitoring scheme and submits the OM&M plan to the permitting authority for approval.  The compliance date is the approval date of the OM&M plan.  The approved OM&M plan will be included by reference in the operating permit.
      The latest date for an existing facility to achieve compliance is 3 years from the date the standard is promulgated.  The OM&M plan must be submitted to the permitting authority for approval no later than 6 months before the planned compliance date.  Given these conditions and lead times for preparing plans and conducting tests, it is clear that owner/operators must act expeditiously to develop test plans and execute the test programs.
      Facilities that choose to comply by demonstrating that each emission unit in the SAPU meets the emission limit for that unit, and by monitoring the parameters as designated in the rule for each emission unit and control device, are also required to develop a test plan and notify the permitting authority of the test date(s).

      4.2.2  Comment:  Several commenters wanted EPA to allow testing one representative unit from a group of similar sources, that is one unit to represent similar furnaces or in-line fluxers, instead of having to test every emission unit.  One of the commenters stated that this practice should be allowed for either controlled or uncontrolled units.  Several commenters claim this approach is widely used under existing State permits and has been used by EPA in other NESHAPs.  Commenters claimed that it would significantly reduce costs, provide flexibility, and provide more cost-effective test programs. (IV-D-9, IV-D-17, IV-D-22, IV-D-23, IV-D-32, IV-D-33, IV-D-35)
      Response:  Based on the comments received, the EPA is modifying the testing requirements to allow representative or similar uncontrolled emission units that use like charge and flux materials to be tested, instead of requiring each unit to be tested.  Testing of representative or similar units may be used provided approval is obtained from the applicable permitting authority.  The representative unit selected for testing must be subject to the same work practices and be of the same design as those emission units it is representing for test purposes.  The representative unit must be tested under worst case conditions.  It is up to the owner/operator to define the worst case scenario(s) for review and approval by the permitting authority.  At least one of each different style unit must be tested.  Each add-on control device controlling emissions from an affected source or emission unit must be tested.

      4.2.3  Comment:  One commenter suggested exempting clean charge furnaces and in-line fluxers from the HCl performance test if chlorine usage is less that emission limit. (IV-D-8) Another commenter requested an alternative to performance testing to show that chlorine usage is less than the emission limit and specifically requested this as an alternative for uncontrolled in-line fluxers. (IV-D-31).  Two other commenters stated that Part II of Pharmaceutical Product NESHAP permitted owners to use calculational methodologies to determine emission rates for individual process vents.  (IV-D-22, IV-D-35)
      Response:	 The EPA agrees that it is reasonable to provide alternate procedures for owner/operators to demonstrate that HCl emissions are less than the emission limit for clean charge furnaces and uncontrolled in-line fluxers.  If the flux (weight equivalent as HCl) usage rate is less than the emission limit for an affected source this is a sufficient demonstration that the  source is in compliance with the standard.  The weight equivalent HCl must be determined for both gaseous and solid reactive fluxes used during the furnace cycle or performance test period.

      4.2.4  Comment:  Submitting the site-specific test plan in accordance with general provision 63.7 would require the plan going to the "Administrator."  The commenter stated that they believe that it's EPA's intent for the plan to go to the applicable regulatory authority. (IV-D-17) Another commenter stated that the proposed requirement to submit performance test plans for approval goes beyond the General Provisions.  The commenter argued that this requirement will greatly increase the burden to permitting agencies and may interfere with schedules needed to complete tests before compliance deadline. (IV-D-32)
      Response:	 The general provisions state that before conducting a performance test the owner/operator of the affected source must develop and, if requested by the Administrator, submit the plan for approval.  Due to the complexity of testing for demonstration of SAPU compliance (facilities with combinations of controlled and uncontrolled emission units, multiple emission units controlled through common control devices, etc.) the Agency has decided that the test plans must be submitted for approval.  The General Provisions at 63.2 define Administrator to mean the Administrator of the U.S. Environmental Protection Agency, or his or her authorized representative (e.g., the State that has delegated authority to implement the provisions of this part).  In the case of authorized states, the plan would go to the permitting authority for approval.
      Facilities having Group 1 furnaces without add-on control devices must develop test data to support their OM&M plan.  Specifically they are required to develop a site-specific monitoring plan as part of the OM&M plan based in part on test data.  If facilities wish to use test data collected during development of the SAPU OM&M plan later as a compliance demonstration, a test plan should be prepared for approval prior to the OM&M plan testing activity.  The benefit to owner/operators in submitting the plan for approval is that they may avoid the necessity of conducting two separate sets of tests, one for OM&M development and one for compliance demonstration.

      4.2.5  Comment:  One commenter stated that the requirement to operate all affected sources connected to a common stack during tests of that common stack is not feasible and not necessary.  The commenter claimed that even at the highest production rate, some facilities may not operate all affected sources simultaneously.  The commenter supports the EPA decision to allow a single test to characterize emissions from multiple sources ducted to a common stack.  Further, the commenter requested that the regulatory paragraph should be expanded to affirm that new emissions units may be ducted to existing control systems, if capacity is available or can be expanded to accommodate the new source. (IV-D-32)
      Response:	 The EPA understands that it may not be feasible to operate all emission units connected to a common stack simultaneously during a performance test.  The intent has been clarified in the final rule by stating that the performance test must be conducted at a maximum production rate scenario, i.e. the number of operating emission units or affected sources connected to the common control device or stack must represent a maximum or highest emission rate condition for the commonly controlled units or sources.
      For the reasons stated in the response to comment 1.6 in this document new emission units may not be cocontrolled with existing units.

      4.2.6  Comment:  One commenter opposed the mandatory retesting every 5 years and claimed that alternative evidence ensuring compliance should suffice.  That is, if the required controls are in place, the floor limits are literally guaranteed according to the preamble of the proposed rule. (IV-D-10)
      Response:	 In general, the presence of required controls is not sufficient to ensure compliance.  Proper operation and maintenance of the control systems are also necessary elements to ensure compliance.  Over a period of years changes may also occur in process operations that affect emissions and control device performance.  For these reasons the requirement to retest every 5 years is being retained in the final rule.

      4.2.7  Comment:  One commenter stated that it is not clear what is meant in 1511(e) of the proposed rule by "at the time of permit renewal."  If the source test results are meant to be used in the renewal application, the testing needs to happen far in advance.  Also the commenter observed that the permit renewal dates may be more than 5 years apart in some cases. (IV-D-20)
      Response:	 It is the EPA's intent that each new or existing affected source or emission unit be retested every 5th year after the initial performance test.  Given that this may not coincide with permit renewal, the final rule has been modified by deleting that phrase from the retesting requirement.

      4.2.8  Comment:  One commenter supported the choice of performance test methods designated by EPA. (IV-D-23)

      Response:	 The EPA acknowledges support of the test method selection.

      4.2.9  Comment:  One commenter requested additional language in the regulation stating that if the format of the emission limit (units, lb/ton) is the same for all units (units ducted to a common control device), compliance is demonstrated if the combined emission limit for all units is not exceeded. (IV-D-23)
      Response:	 For units that are all part of the same SAPU no additional language is necessary, emission limits are all written in the same format (e.g. lbs/ton).  Compliance is demonstrated if the combined emission limit for all units is not exceeded.  For other existing sources, such as delacquering kilns and furnaces going to a common fabric filter, a case-by-case compliance demonstration is required with the permitting authority providing approval of the test plan before the tests are conducted.

      4.2.10  Comment:  Section 63.1511(f)(3) of the proposed rule, regarding establishment of operating and monitoring parameter values, that existing data may be used if, among other conditions, no design or work practice changes have been made since the time the previous data were reported in order to make the previous data acceptable for compliance demonstration.  Two commenters observed that not all work practice or design changes will affect emissions or the operating parameters.  The commenters requested a clarification that only design and work practices affecting emissions may not have changed since the previous report in order for the data to be an acceptable demonstration. (IV-D-17, IV-D-23)
      Response:	 The proposed provision required the owner/operator to certify that no changes in work practice or design have been made since the previous data were obtained.  It also stated that the conditions must be met to the satisfaction of the permitting authority.  If changes have been made and the owner/operator believes the changes have no bearing on emissions, the owner/operator can include an explanation for review and consideration by the permitting authority.  The permitting authority would determine whether to accept the previous data after consideration of whether all the necessary conditions have been met.  The final rule retains the provision as proposed in 63.1511(g).

      4.2.11  Comment:  One commenter stated that sources should be able to use test results obtained prior to the compliance deadline as a demonstration of compliance. (IV-D-28)

      Response:  Test results obtained with the methods required for performance testing in the final rule, in coordination with development of the required operating and monitoring parameter values or ranges as required in the final rule, may be used as a demonstration of compliance at the compliance deadline, provided that all the conditions of 63.1511(g) cited in the previous comment have been met.  Submittal of all the necessary supporting information and data would be part of the OM&M plan preparation, review, and approval process with the permitting authority.

      4.2.12  Comment:  One commenter requested that different affected sources connected to a common control device be permitted the flexibility to allow consistent monitoring and compliance periods, for example a delacquering kiln and SAPU furnaces. (IV-D-23)
      Response:	 Although the example provided by the commenter is a case in which the emission limit formats are the same for different affected sources, the pollutants regulated, and the monitoring and compliance periods will be different.  The difference in the monitoring and compliance period for different affected sources can be significant.  For example SAPU compliance is determined on the basis of 3-day, 24-hour rolling average emissions and delacquering kilns are based on the average of three 3-hour test runs.  Furthermore, there is no legal construct under the CAA that provides for emissions from two different affected sources to be averaged.  The final rule requires that compliance for different affected sources must be determined separately.

      4.2.13  Comment:  One commenter suggested improved wording for 1511(b)(4) of the proposed rule as follows: "Where multiple affected sources or emission units are exhausted through a common stack, pollutant sampling for each run must be conducted over a period of time during which all affected sources or emission units complete at least one entire process operating cycle or for 24 hours, whichever was shorter. (IV-D-20)
      Response:  The EPA has adopted the suggested wording change in the final rule.

      4.2.14  Comment:  One commenter stated that the wording in Section 63.1512(j) of the proposed rule presumes there are always control devices present on emission units within the SAPU because testing is required at the outlet to the control device.  However, some emission units may not be controlled, so the requirements will need to be reworded. (IV-D-20)
      Response:	The commenter correctly noted that a wording change is necessary to include testing for uncontrolled emission units.  The final rule has been modified to incorporate the language changes at 63.1512(e).

      4.2.15  Comment:  One commenter stated that testing, especially for area sources, is needlessly burdensome and expensive.  According to the commenter, the EPA should provide an option to use reliable emission factors.  The owner should not be required to test at highest production level if they can show it would never or could never be operated at such.  There should be something like synthetic minor status available.  The commenter claimed that having to submit results of "any" test will discourage owners from exploring alternative operating scenarios; owners should have the choice to test actual emissions and control HAPs based on feed material certification instead of controlling PM. (IV-D-27)
      Response:  Area sources mentioned by the commenter are only  being regulated for D/F emissions from the processes for which D/F emission limits have been established.  Therefore area sources are not required to control PM under this rule.  The EPA recognizes that testing of sources to determine D/F emissions may be relatively costly in comparison to the cost of some process equipment subject to the rule, and amount of material processed in the affected source, i.e. sweat furnaces.  There are not reliable emission factors available for estimation of D/F emissions for regulatory purposes.
      As a result of comments received, and after further consideration, the EPA has determined to revise the standard for sweat furnaces.  The final rule provides that a sweat furnace equipped with an afterburner with 2 second residence time and with a design temperature of at least 1600 F is not required to conduct a performance test to demonstrate compliance with the D/F emission limit.  The D/F emission limits proposed are being retained in the final rule.  Owner/operators of sweat furnaces located at facilities which are area sources can elect to demonstrate compliance with the D/F emission limits for those existing afterburners that may not meet the equipment specifications through a one-time test.

4.3  Notifications, Reports, and Records

      4.3.1  Comment:  One commenter noted that the compliance certification requirement in Section 63.1516(c) of the proposed rule limits the information required in annual compliance certifications.  The commenter suggested making the language consistent with 40 CFR 70.6(5)(iii) which is included in their comment.  The suggested language is much broader than that of the proposed rule. (IV-D-20)
      Response:	The EPA did not intend to limit the information that could be required in annual compliance certifications by the permitting authority.  The wording has been changed in the final rule to state that compliance certification must "at least" contain the items listed.

      4.3.2  Comment:  One commenter requested the requirement to develop a Startup, Shutdown, and Malfunction (SSM) plan to apply only to controlled sources.  The same commenter wanted to eliminate the requirement to certify the use of only "non-HAP containing, non-HAP generating flux gases" from the reporting provision of Section 63.1517(b)(2)(vi) of the proposed rule for in-line fluxer using no reactive flux, and certify only "non-reactive flux gases" are used.  (IV-D-31)

      Response:	While the add-on air pollution control devices play the primary role in emission control, variation in the process operations generating the waste gas stream and pollutants affect the emissions as well.  Further, these standards anticipate the presence of emission units using pollution prevention approaches rather than add-on controls as part of secondary aluminum processing units in many facilities.  These  emission units and the associated work practices and pollution prevention measures are the means by which emissions are limited in the SAPU.  For these reasons, and consistent with the General Provisions, all affected sources and emission units must be included in the SSM plan.
      The certification requirement for "in-line fluxer using no reactive flux" has been retained in the final rule as it was proposed.  This provision is necessary for consistency with the requirements for group 2 furnaces.  Both emission units have no emission limits and are therefore subject to this more stringent certification statement.

      4.3.3  Comment:  One commenter stated that the requirement for the quality improvement plan (QIP) in 63.1515(b)(11) of the proposed rule should be deleted because this is the only place in the rule it is mentioned. (IV-D-17)  Another commenter asked for a clarification stating that if the QIP in 1515(b)(11) of the proposed rule refers to the QIP of 40 CFR 64, EPA should clearly state that. (IV-D-20)
      Response:  This reference to the Quality Improvement Plan was inadvertently left in the proposed rule when published; it was not intended to be a requirement and has been removed.

4.4  Applicability of General Provisions

      4.4.1  Comment:  One commenter provided a table with comments supporting or opposing, and noting no or neutral comments, on the applicability of each of the General Provisions requirements shown in Appendix A to Subpart RRR. (IV-D-23)
      Response:  The EPA has reviewed applicability of the general provisions and, except as noted in Appendix A to the final rule, all of the general provisions apply to this subpart.

5.	Impacts

      5.1  Comment:  Several commenters (IV-D-12, IV-D-14, IV-D-15, IV-D-16, IV-D-18, IV-D-19, IV-D-20, IV-D-21, IV-D-23, IV-D-27, IV-D-30, IV-D-32) disagreed with the results of EPA's regulatory impact analysis and believed that EPA underestimated the cost of the rule.  The commenters identified the following as deficiencies in the impact analysis:

      1)  The EPA underestimated the number of area sources that would be impacted as a result of the area source D/F standard.  In particular, owners or operators of sweat furnaces, die casting facilities, foundries, and extruders were identified as potentially affected area sources that were either excluded or not adequately accounted for in the analysis.  Furthermore, the commenters claimed that the proposed monitoring, recordkeeping, and reporting, and title V permit requirements would impose a significant burden on area sources.
      2)  The EPA understated the number of small businesses that would be affected by the rule and, as a result, EPA's analysis of impacts on small entities was not adequate.  According to several of the commenters, the small business impacts analysis underestimated small business impacts because it did not accurately account for sweat furnaces, die casting facilities, foundries, and extrusion facilities, many of which are small businesses and would be subject to the rule.  The commenters also claimed that the proposed monitoring, recordkeeping, reporting, and title V permit requirements would impose significant burdens on these small businesses.  They argued that the rule would have a significant impact on a substantial number of small entities and that EPA must, therefore, perform a regulatory flexibility analysis as required by the Regulatory Flexibility Act.
      3)  Commenters took issue with the methods and assumptions used by EPA to estimate the costs and economic impacts of the rule, including failure to adequately account for the large number of affected area sources, title V permitting costs for area sources, and underestimating performance test costs due to the assumption of shared stacks.  As a result, the commenters state that EPA's costs and economic impact estimates are too low.  They argue that the annualized cost of the rule exceeds $100 million and is, therefore, a significant regulatory action under Executive Order 12866.
      Response:  Based on the numerous comments received regarding the regulatory impact analysis, the EPA has reviewed, revised, updated, and refined the analysis to address commenters' points:

      1)  With regard to commenters' first point, for the proposed rule, the EPA used the information available on area sources of D/F emissions and requested additional information on the number of area sources, levels of emissions from these sources, the level of control currently employed, and the number of area sources that are also small businesses.  In response to the comments on the proposed rule, and using the information provided by commenters on sweat furnaces, die casting facilities and foundries, EPA has reassessed the cost of the rule on area sources (see Docket item IV-B-4).  In addition, EPA has clarified and, in some cases, revised the proposed rule to address commenter concerns that the proposed rule will be overly burdensome for area sources.  These changes include clarifications or revisions in the applicability of the rule, the performance testing requirements, the scrap inspection program, and giving the State permitting authorities the discretion to defer the requirements for a title V permit for area sources.  On the basis of the information submitted to EPA during the public comment period and changes made to the proposed rule that narrow the applicability to facilities that are area sources (primarily aluminum extruders, die casters, and foundries), the EPA believes the number of those facilities subject to the rule to be small.
      2)  Regarding the commenters' second point, after reviewing the comments on the small business impacts of the proposed rule and using the information on sweat furnaces, die casting facilities, and foundries provided by commenters, EPA has refined its small business impacts analysis (see Docket item IV-B-6).  The analysis shows that the final rule will not have a significant impact on a substantial number of small businesses; therefore, no regulatory flexibility analysis is required.  The small business impact analysis shows that the impact to small businesses operating sweat furnaces, and to small firms in the aluminum die casting and aluminum foundry industries is minimal.
      3)  Regarding the commenters' third point, EPA considered the comments objecting to the costing methods and assumptions it used to estimate the impacts of the proposed rule.  The EPA has reexamined its cost estimating procedures and believes that overall it has overstated the cost of the proposed rule.  However, in view of the changes in the proposed rule, and to incorporate revisions in the estimated number of affected area sources, EPA has updated its estimate of the cost of the rule (see Docket item IV-B-4 and IV-B-5).  The revised cost of the rule is below the $100 million per year threshold, therefore, the rule is not a significant regulatory action as defined under Executive Order 12866.

      5.2  Comment: One commenter claimed that under the proposed rule one of their facilities would be unable to use their existing monitoring procedures, which were approved by EPA and the State of Washington, e.g., data from existing COMs under existing SIP procedures, single upstream chlorine feed monitoring, and an existing weigh feeder for trona injection (more accurate and reliable than proposed EPA visual inspection).  The cost of the facility's existing monitoring systems exceeds those monitoring costs estimated by EPA for similar model plants.  This commenter also claims that EPA substantially underestimated costs for installing and operating monitoring systems by comparing costs for their facility to EPA Model Plant 6. (IV-D-32)

      Response: In considering the comment, EPA notes that the monitoring and operating requirements of the rule have been revised to be less prescriptive and provide greater flexibility for affected sources. The final rule has been revised to provide for approval of site-specific monitoring and operating alternatives, within EPA guidelines, by the permitting authority.  However, should an owner/operator find that the provisions in the final rule for getting approval of site-specific plans do not cover a particular situation or fail to meet their needs, the General Provisions provide for the use of alternatives to monitoring requirements or procedures upon approval by the Administrator.  EPA believes that these revisions to the rule provide industry with the flexibility necessary to comply with the monitoring requirements efficiently and at a reasonable cost.

      5.3  Comment: One commenter stated that because they never have been required to measure D/F emissions, they may have to spend $100,000 per plant site just to establish what their emissions are and that the additional cost of controls is unknown until they establish their baseline emissions.  In addition, record keeping requirements will require additional staffing just to take readings.  The commenter concludes that the rule will have major economic impacts and potential to shut down a number of operations.  Another commenter stated that they surveyed 10 testing firms and found the median cost of D/F testing to be $12,000 per source based on tests on medical/infectious waste incinerators and concluded that the average sweat furnace testing costs could easily be 25% of the capital cost of a furnace ($45,000), yielding a significant impact. (IV-D-13, IV-D-7)
      Response: In response to the first commenter, EPA has revised the rule so that it no longer requires testing of each piece of equipment where sources are uncontrolled and are similar from the standpoint of design and operation.  In addition, because area sources only perform an initial compliance test, they will incur lower costs for testing than major sources which are required to retest every 5 years.
      Regarding the concerns of the second commenter, a manufacturer of sweat furnaces, EPA notes that the cost used by EPA to assess impacts is almost double the cost cited by the commenter.  Furthermore, where the sweat furnace afterburner meets the final rule's design specifications, the owner/operator is not required to perform emissions testing, but must only monitor the afterburner operating temperature.

      5.4  Comment:  One commenter stated that the rule should provide incentives to identify innovative approaches to emission reductions, and if not, it should allow innovative approaches with the least net economic effect. (IV-D-9)
      Response: The rule does provide for the use of pollution prevention and innovative approaches to reduce emissions by allowing owners/operators to develop site-specific plans for monitoring and operations, grouping in-line fluxers and group 1 furnaces to allow SAPU compliance demonstrations to be conducted in the most cost-effective way, and requiring site specific work practices to prevent or limit the use of materials in furnace operations that result in HAP emissions.

      5.5  Comment:  Benefits of recycling should be considered in regulating this category.  Recycling offsets environmental harms associated with production and use of virgin materials.  Because recycling itself is a pollution prevention activity the Agency might consider providing a recycling credit that reduces or modifies limits for affected facilities, such as an offset determination that contributes toward meeting emission control levels. (IV-D-27)
      Response: EPA agrees that recycling is environmentally beneficial in that it saves resources.  But because the secondary aluminum production industry also releases hazardous air pollutants listed in the Act, and the industry is listed as a source category for regulation under the Act, EPA is required to develop technology-based (MACT) standards for the industry.

      5.6  Comment:  One commenter took issue with certain health-related documents contained in the docket as well as length of the preamble's discussion of the health effects of the pollutants.(IV-D-23)
      Response: The commenter's criticisms were not directed at the rule but at certain docket items and the discussion of health effects in the preamble.  Although consideration of health risks do not enter into the analysis of regulations that are set at the floor level of control as is the case with this regulation, EPA believes that the information presented in the preamble and the supporting docket material is needed to fully inform the public of the health risks associated with the hazardous air pollutants covered by this rule.

      5.7  Comment:  EPA presented model results based on four model plants for 384 meteorological sites, the worst risk from which was in Hawaii.  The commenter stated that because this site has unusual air dispersion characteristics, and EPA did not consider activity patterns and indoor/outdoor exposure gradients, that the  potential impacts are overly conservative. (IV-D-23)
        The same commenter stated that the potential health impacts from HCl exposure are exaggerated due to large safety factors applied in developing the RfC from the Lowest Observable Adverse Effect Level (LOAEL).  The commenter provided a review of the derivation of the IRIS RfC for HCl in a report by a consultant.  In addition the consultant addressed other conservative assumptions related to the exposure assessment that in their opinion causes EPA's exposure estimates to be overstated.
      Response:  The comments address methods EPA used in assessing exposure to hazardous air pollutants and the associated health risks.  As noted above, the consideration of health risks do not enter into the analysis of regulations that are set at the MACT floor and the rule for secondary aluminum production facilities is set at the MACT floor.

      5.8  Comment:  One commenter feels that enforcement of the NESHAP will be unequal because some state agencies (e.g., South Coast Air Quality Management District) are better staffed and trained to implement new laws.  The commenter is concerned that facilities in Southern California will be handicapped by the standards in comparison to facilities in other locales. (IV-D-10)
      Response: EPA understands that implementation and enforcement of any rule may vary among agencies depending on several factors but believes that the differences will be minimal.  In addition, nothing in the CAA precludes adoption of more stringent standards by any State.

      5.9  Comment:  One commenter noted that there are many differences between the proposed NESHAP and the control measures required by the state regulatory agency.  This commenter stated the most effective way to integrate the federal and state requirements is to revise the state permits to incorporate the relevant federal requirements.  The proposed amendments to 40 CFR Part 63, Subpart E, Approval of State Programs and Delegation of Federal Authorities, allow the use of district operating permits or Title V permits for making equivalency determinations, but the amendments place a limit on the number of individual sources for which permits may be used in determining equivalency between federal and state programs.  The commenter opposes limits on the number of individual sources that can use permits to determine equivalency. (IV-D-19)
      Response: The commenter's concern is in reference to State permit programs and is not relevant to this action.