Table 5.  HCl MACT Floor
                                     Kiln
                         HCl Emissions (ppmvd @ 7% O2)
                                       1
                                     0.02
                                       2
                                     0.02
                                       3
                                     0.22
                                       4
                                     0.97

                               MACT  -  Existing
Average
                                     0.31
Variability (t*vT[0.5])
                                     1.94
99[th] percentile
                                       2
                                 MACT  -  New
Average
                                     0.02
Variability (t*vT[0.5])
                                     0.12
99[th] percentile
                                      0.1

	MACT for new kilns is based on the performance of the lowest emitting kiln.  The average HCl emissions for the lowest emitting kiln in this data set is 0.02 ppmv.  Using the same statistical technique to apply run-to-run variability for that kiln's emissions data, the HCl MACT floor for new kilns is 0.14 ppmvd at 7 percent O2.
	For facilities that do not use wet scrubbers to meet the HCl limit, these standards would be based on a 30-day rolling average, consistent with the proposed use of CEMS (i.e., continuous measurements) for compliance.  See section E below.
	It should be noted that these emission limits are below the published detection level of the test method (EPA test method 321).  This issue is further discussed in section IV.I.
Beyond the Floor Standard for HCl
Based on the HCl emissions data, most kilns (both existing and new) would have to install limestone scrubbers in order to comply with the proposed floors for HCl.  Scrubbers are expected to reduce HCl emissions by an average of at least 99 percent.  Scrubbers added to reduce HCl emissions will also reduce emissions of SO2 and will remove oxidized mercury as well.
      In examining a beyond-the-floor option for HCl, we evaluated the use of a more efficient HCl scrubber.  We assumed a spray chamber scrubber is sufficient to meet the MACT floor, and that scrubber is expected to remove HCl at an efficiency of 99 percent (as just noted).  However, we estimate that a packed-bed scrubber would have removal efficiency greater than a spray chamber due to its increased surface area and opportunity for contact between the scrubbing liquid and the acid gases.  We estimated the costs and emission reductions for a 1.2 million tpy kiln as the cost-effectiveness results would be similar for all kilns. Annual costs for a packed bed scrubber for a 1.2 million tpy kiln would be approximately $2.2 million.
Assuming a control efficiency of 99.9 percent, the incremental emission reduction using the beyond-the-floor packed-bed scrubber, that is, the reduction in HCl emissions after initial control by the MACT floor control (a spray chamber scrubber), would be about 2.4 tpy. At an annual cost of $2.2 million, the cost effectiveness is $929,000 per ton of HCl removed.  Adverse non-air quality impacts, such as energy costs, water impacts, and solid waste impacts would be expected to be similar for both the floor and beyond-the-floor level of control.  Considering the high costs, high cost effectiveness and small additional emissions reduction (and adverse cross-media impacts), we do not believe that a beyond-the-floor standard for HCl is justified.
Other Alternatives for HCl standards
One option to HCl standards that we considered would be to set a standard that used SO2 as a surrogate for HCl.  The reason to allow this option would be that some kilns already have SO2 controls and monitors.  Acid gas controls that remove SO2 also remove HCl at equal or greater efficiency.  However, we are not proposing this option because we have no data to demonstrate a direct link between HCl emissions and SO2 emissions  -  that is , it is unclear that ranking best HCl performers based on SO2 emissions would in fact identify lowest emitters or best controlled HCl sources.  We are requesting comment on the efficacy of using SO2 as a surrogate for HCl, and data demonstrating that SO2 is or is not a good surrogate for HCl.
We also considered the possibility of proposing a health- based standard for HCl.  Section 112(d)(4) allows the Administrator to set a health based standard for a limited set of HAP: "pollutants for which a health threshold has been established".  EPA may consider that threshold, with an ample margin of safety, in establishing standards under section 112 (d).  In the 2006 rule, EPA relied on this authority in declining to establish a standard for HCl, finding that no source in the category would emit HCl at levels which would exceed the No Observed Effect Level for HCl with an ample safety margin.  71 FR at 76527-29.
However, we are not proposing a health-based standard.  This decision is based on the fact that, in addition to the
direct effect of reducing HCl emissions, setting a MACT standard
for HCl is anticipated to result in a significant amount of
control for other pollutants emitted by cement kilns, most
      notably SO2 and other acid gases, along with condensable PM, ammonia, and semi-volatile compounds.  For example, the additional reductions of SO2 alone attributable to the proposed MACT standard for HCl are 105,000 tpy.  These are substantial reductions considering the low number of facilities.  Although MACT standards may only address HAP, not criteria pollutants, Congress fully expected MACT standards to have the collateral benefit of controlling criteria pollutants as well, and viewed this as an important benefit of the air toxics program.  S. Rep. No. 101-228 101[st] Cong. 1[st] sess. at 172.  It therefore is appropriate that EPA consider such benefits in determining whether to exercise its discretionary section 112 (d)(4) authority.
It should also be noted that the CAA gives EPA the option to create a health-based standard for threshold pollutants.  Generally, without adequate evidence that a pollutant may be a carcinogen (and therefore likely being a non-threshold pollutant), EPA has assumed there is an effect threshold.  For HCl, the Integrated Risk Information System (IRIS) indicates that EPA has derived an inhalation reference concentration for HCl of 20 ug/m[3].  Long-term exposure at or below this level is believed to be without appreciable risk of chronic non-cancer effects.  However, HCl has not been evaluated by the IRIS program to determine its carcinogenicity.  Additionally, the International Agency for Research and Cancer (IARC) found HCl not classifiable as a carcinogen to humans due to inadequate evidence in humans and lab animals. We request comment on the evidence necessary to determine whether a HAP, in this case HCl, is or is not a threshold pollutant, and any additional data on the carcinogenicity of HCl, and other information on HCl health and environmental effects we should consider.  Commenters should also address the issue of other environmental benefits which might result from control of HCl at a MACT level, including control of other acid gases and control of secondary PM (i.e., PM condensing from acid gases).  We will consider these comments in making an ultimate determination as to whether to adopt a health-based standard for HCl.
Finally, we determined that even if we opted to set a health based standard, we would still need to set a numerical emission limit given that section 112(d)(4) still requires that an actual emission standard be in place.  In order to determine this level, we conducted a risk analysis of 68 facilities using a screening level dispersion model (AERSCREEN).  Utilizing site specific stack parameters and worst-case meteorological conditions, AERSCREEN predicted the highest ground level concentration surrounding each facility. The results of this analysis indicated that an emission limit of 23 ppmv or less would result in no exceedances of the NOEL for HCl with a margin of safety.  Although, as discussed above, EPA is not proposing a health-based standard, EPA solicits comment on the level of 23 ppmv (as a not-to-exceed standard) should EPA decide to pursue the option of a health-based standard.
E.	Determination of MACT for PM Emissions from Major and Area Sources

	Existing and new major sources are presently subject to a PM limit of 0.3 lb/ton of feed which is equivalent to 0.5 lb/ton clinker.  EPA is proposing to amend this standard, and also is proposing PM standards for existing and new area source cement kilns.  In all instances, PM serves as a surrogate for nonvolatile metal HAP (a determination upheld in National Lime Ass'n, 233 F. 3d at 637-39).  EPA is proposing to revise these limits because they do not appear to represent MACT, but rather a level which is achievable by the bulk of the industry. See 63 FR at 14198.  This is not legally permissible.  Brick MACT, 479 F. 3d at 880-81.
      We compiled PM stack test data for 45 kilns from the period 1998 to 2007.  EPA ranked the data by emissions level and the lowest emitting 12 percent, 6 kilns, was used to develop the proposed existing source MACT floor.
	As for the previous floors, we calculated the variances of each kiln and accounted for variability by determining the 99[th] percentile UPL as described earlier.  The average performance for each of the lowest emitting kilns was generally based on the average of 3 runs which comprise a stack test.  Consequently, the variability represents the short term variability at a kiln (e.g., a 3 hour stack test period) and the variability across the 6 lowest emitting kilns.  (This analysis is consistent with the way we would propose to determine compliance, i.e., conduct 3 runs to perform a stack test.)  For the lowest emitting kiln (whose performance was used to establish the new source floor), there were only 3 runs with results that were relatively close together, which is inadequate to estimate the kiln's long term variability.  However, we know the 6 lowest emitting kilns are equipped with fabric filters that are similar with respect to performance because they are similar in design and operation, and the larger dataset provides a much better estimate of the variability associated with a properly operated fabric filter.  Consequently, for the proposed new source floor, we used the average performance of the lowest emitting kiln and the variability associated with the best fabric filters to assess the best performing kiln's variability.
      The emissions for the top six kilns ranged from 0.005 to 0.008 lb/ton clinker.  Accounting for variability as described above, we calculated an existing source MACT floor of 0.085 lb/ton clinker.  For new kilns, the limit is based on the best lowest emitting kiln, which has emissions of 0.005 lb/ton clinker.  Accounting for variability results in a calculated new source MACT floor of 0.080 lb/ton clinker.  The PM emissions data are summarized in Table 6.

                            Table 6.  PM MACT Floor
                                     Kiln
                         PM Emissions (lb/ton clinker)
                                       1
                                     0.005
                                       2
                                    0.0075
                                       3
                                    0.0075
                                       4
                                    0.0081
                                       5
                                    0.0108
                                       6
                                    0.0232
                                MACT - Existing
Average
                                     0.010
Variability (t*vT[0.5])
                                     0.075
99[th] percentile
                                     0.085
                                  MACT - New
Average
                                     0.005
Variability (t*vT[0.5])
                                     0.075
99[th] percentile
                                     0.080

	EPA is also proposing to set a PM standard based on MACT for existing and new area source cement kilns.  Portland cement kilns are a listed area source category for urban HAP metals pursuant to section 112(c)(3), and control of these metal HAP emissions (via the standard for the PM metal surrogate) is required to ensure that area sources representing 90 percent of the area source emissions of urban metal HAP are subject to section 112 control, as required by section 112(c)(3).  EPA is proposing that this standard reflect MACT, rather than GACT, because there is no essential difference between area source and major source cement kilns with respect to emissions of either HAP metals or PM.  A common control strategy consequently is warranted for these emissions.  Thus, the factors that determine whether a cement kiln is major or area are typically a function of the source's HCl or formaldehyde emissions, rather than its emissions of HAP metals.  As a result, there are kilns that are physically quite large that are area sources, and kilns that are small that are major sources.  Both large and small kilns have similar HAP metal and PM emissions characteristics and controls.  We thus have included all cement kilns in the floor calculations for the proposed PM standard, and have developed common PM limits based on MACT for both major and area sources.
Consideration of Beyond-the-Floor Standards
      There is very little difference in the proposed floor levels for PM for either new or existing sources, and we believe that a well-performing baghouse represents the best performance for PM.  To evaluate beyond-the-floor controls, we examined the feasibility of replacing an existing ESP or baghouse with a new baghouse equipped with membrane bags which might result in a slightly better performance for PM (reflected in the modest increment between the proposed floors for new and existing sources). We estimated the costs and emission reductions for a 1.2 million tpy kiln. The cost-effectiveness results will be similar for all kilns. Under the MACT floor, baseline emissions of 0.34 lb/ton of clinker are reduced to 0.085 lb/ton of clinker, a reduction in PM emission of 51 tpy. Further reducing emissions down to the proposed PM limit for new sources would incrementally reduce emissions by an additional 3 tpy. The annualized cost of a baghouse with membrane bags would be $1.73 million per year, or a cost effectiveness of $576,000/ton of PM (far greater than any PM reduction EPA has ever considered achievable under section 112(d)(2) or warranted under other provisions of the Act which allow consideration of cost). Assuming that the metal HAP portion of total PM is 1 percent, the cost effectiveness would be about $58 million per ton of metal HAP. Based on these costs and the small resulting emission reductions, we believe a PM beyond-the-floor standard is not justified for existing sources and not technically feasible for new sources.
Other Standards for PM
      Emissions from fabric filters or ESP are typically measured as a concentration (grains per dry standard cubic feet) and then converted to the desired format using standard conversions (54,000 dry cubic feet per minute of exhaust gas per ton of feed, 1.65 tons of feed per ton of clinker).  All of the data used to set the proposed PM emissions limit were converted in that fashion.  Therefore, the basis of the proposed PM standard is actually a concentration level.  There are certain cases where this conversion must be adjusted, however.  Some kilns and kiln/in-line raw mills combine the clinker cooler gas with the kiln exhaust and send the combined emissions to a single control device.  There are significant energy savings (and attendant greenhouse gas emission reductions) associated with this practice, since heat can be extracted from the clinker cooler exhaust.  However, there need to be different conversion factors from concentration to mass per unit clinker.  In the case where clinker cooler gas is combined with the kiln exhaust the standard would need to be adjusted to allow for the increased gas flow.  If this allowance is not made, then the effective level of the PM standard would be reduced (the result being that the proposed standard would not properly reflect best performing kilns' performance, and also discouraging use of a desirable energy efficiency measure).  Therefore, we are proposing that facilities that combine the kiln and clinker cooler gas flows prior to the PM control would be allowed to convert the equivalent concentration standards (which are 0.0067 or 0.0063 for new and existing sources, respectively) to a lb/ton clinker standard using their combined gas flows (dry standard cubit feet per ton of feed).  It should be noted that this provision will not result in any additional PM emissions to the atmosphere compared to the same kiln if it did not combine the clinker cooler and kiln exhaust, and may actually decrease emissions slightly due to improvements in overall process efficiency.
	In addition to proposing to amend the PM standard for kilns we are also proposing to similarly amend the PM emissions limit for clinker coolers.  Fabric filters are the usual control for both cement kilns and clinker coolers.  As EPA noted in our proposed revision to Standards of Performance for Portland Cement Plants (73 FR 34078, June 16, 2008) we believe that the current clinker cooler controls can meet the same level of PM control that can be met by the cement kiln.  Therefore, we are proposing as MACT the same PM emissions limits for both clinker coolers and kilns.
	In sum, because we believe that the costs of a beyond-the-floor standard for PM are not justified, we are proposing a PM standard for existing kilns and clinker coolers of 0.085 lb/ton of clinker, and for new kilns and clinker coolers of 0.080 lb/ton of clinker.
F.	Selection of Compliance Provisions
	For compliance with the mercury emissions standards we are proposing to require CEMS (either instrument based or sorbent trap based).  As we have previously noted, we do not believe that short term emission tests provide a good indication of long term mercury emissions.  We considered the option of measuring and analyzing the raw materials, as was done to gather the data used to develop the proposed standards.  However, that data gathering was done based on a daily analysis of all inputs to the kiln.  If we were to make that the compliance option and require daily analyses, the cost would be comparable to the cost of a mercury monitor.  If we were to allow less frequent analyses to reduce costs, then we are concerned that the accuracy may be reduced (and the standard would no longer be implemented in the same manner as it was developed).  In addition, in order to meet the proposed mercury emission limits, we anticipate that many facilities will install add-on controls, which will create another variable that would make the measurement of mercury inputs as a surrogate for a continuous stack measurement less accurate.  In order to determine an outlet emissions rate based on input measurements, the control device would have to be tested under various operating conditions to insure that the removal efficiency could be accurately calculated, and parametric control device monitoring would be required.  Given issues related to input monitoring, and the cost associated with control device monitoring, plus a desire to implement the standard in a manner matching its means of development, we believe that a continuous mercury measure at the stack is the preferred option, and are proposing that sources demonstrate compliance with mercury monitors meeting the requirements of PS-12A or PS-12B.

      Generally, we propose and promulgate monitoring system performance specifications and performance test methods in accordance with their development, independent of publication of source category emissions control regulations.  There are circumstances dictating that we publish such measurement procedures and requirements simultaneously with an emissions regulation because of integral technical relationships and because such a combination is convenient and cost-effective. Such combined publication also allows commenters to prepare comprehensive comments on not only the performance specifications or test methods but also on their specific applications.  In today's notice, we propose to amend 40 CFR part 60, appendix B by adding Performance Specification 12A  -  Specifications and Test Procedures For Total Vapor Phase Mercury Continuous Emission Monitoring Systems in Stationary Sources and Performance Specification 12B - Specifications and Test Procedures For Monitoring Total Vapor Phase Mercury Emissions from Stationary Sources Using a Sorbent Trap Monitoring System.
      We published versions of these performance specifications with the electric utility mercury MACT rule.  On March 14, 2008, the DC Circuit Court issued a mandate to vacate the Clean Air Mercury Rule which included that MACT rule clouding the status of these measurement procedures.  We are republishing the performance specifications today to clarify the status of those procedures particularly in their applicability to source categories in addition to coal-fired electric utilities.  In this case, our analyses show
       that mercury emissions from portland cement kilns exhibit most, if not all, of the same physical and chemical characteristics as mercury emissions from coal-fired electric utilities.  Since Performance Specifications 12A and 12B are suitable for use in measuring emissions from portland cement kilns, we also believe that these measurement procedures with minor revision also apply to other sources.  We believe that the simultaneous proposal of these performance specifications revised to reflect broad applicability with today's Portland Cement MACT proposal is appropriate.  The combined notice of proposals is cost-effective, and affords commenters the ability to provide comprehensive comments."
	We are aware that there are currently no cement kilns in the U.S. that have continuous mercury monitors.  However, there are numerous utility boilers that have certified mercury CEMS.  We see no technical basis to say that continuous mercury monitors will not work as well on a cement kiln as they do on a utility boiler.  In addition, there are 34 cement kilns that have operating continuous mercury monitors in Germany.
	For demonstrating compliance with the proposed THC emissions limit we are proposing the use of a CEMS meeting the requirements of PS-8A.  This requirement already exists for new kilns.  There are existing kilns that already have THC CEMS, and indeed, EPA used CEMS data from these kilns as the basis for the proposed standards.  As previously noted, changes in raw materials can materially affect THC emissions without any obvious indication that emissions have changed.  For this reason, and to be consistent with the means by which EPA developed the proposed standard, we believe (subject to consideration of public comment) a CEMS is necessary to insure continuous compliance.
      	If a source chooses to comply with the alternative organic HAP emissions limit, rather then the THC limit, we are not planning to propose the use of a continuous monitor to directly measure organic HAP because organic HAP monitors are not available for this application.  We are proposing to use EPA Method 320 to determine the actual organic HAP content of the THC at a specific facility.  If Method 320 indicates compliance with the alternative organic HAP standard, then the THC emissions measures using a CEMS would become that site's THC limit (assuming that the THC emissions measured during the testing exceed the MACT floor values of 7 ppmvd for existing sources and 6 ppmvd for new sources).
	For demonstrating compliance with the proposed PM emissions limit, we are proposing the installation and operation of a bag leak detection system, along with stack testing using method     conducted at a frequency of five years.  If an ESP is used for PM control an ESP predictive model to monitor the performance of ESP controlling PM emissions from kilns would be required, as well as a stack performance test conducted at a frequency of five years.  As an alternative a PM CEMS that meets the requirements of PS-11 may be used. We are also proposing to eliminate the current requirement of using an opacity monitor to demonstrate continuous requirement with a PM standard for kilns and clinker coolers.

We previously proposed use of bag leak detection systems for PM as part of our review of the Portland Cement Standards for Performance under section 111 of the Act (73 FR 34072, June 16, 2008).  Our rationale for extending the requirement to existing kilns is that given the stringent level of the proposed PM emissions limits we do not believe that opacity is an accurate indicator of compliance with the proposed PM emissions limit.  In addition, we are removing the opacity standard and opacity continuous monitoring requirements for any source that uses a PM CEMS or bag leak detector to determine compliance with a PM standard.  (Some opacity requirements, such as those for materials handling operations, will remain in place).

	For demonstrating compliance with the HCl emissions limit we are proposing the use of a CEMS that meets the requirements of PS-15 if the source does not use a limestone wet scrubber for HCl control.  As with mercury and THC, HCl emissions can be significantly affected by inputs to the kiln without any visible indications.  For this reason we believe that a continuous method of compliance is warranted.  If the source uses a limestone wet scrubber for HCl control, we believe that HCl emissions will be minimal even if kiln inputs change because limestone wet scrubbers are highly efficient in removing HCl.  For this reason we are proposing to require sources using a limestone wet scrubber to perform an initial compliance test using EPA Test Method 321, and to test every 5 years thereafter.  These EPA Test Method 321 testing requirements would also apply to sources using CEMS.  In addition, for sources with in-line raw mills that are not using a wet scrubber for HCl control, we are proposing to require testing with raw mill on and raw mill off.  Our review of the available data where a kiln was tested with raw mill on/raw mill off indicated that the change in raw mill operating conditions had a significant influence in HCl emissions.  We are specifically requesting comment on our assumption that a wet scrubber will consistently maintain a low level of HCl emissions, even if feed conditions change, and thus it is appropriate to use a short term performance test rather then a continuous monitor for kilns that install wet scrubbers.
	One option we considered would be to require SO2 monitoring in lieu of HCl monitoring.  The reason to allow this option would be that some kilns already have SO2 monitors, and this monitoring technology is less expensive and more mature than HCl monitors.  If a source is using a wet scrubber for HCl control, then indication that the scrubber is removing SO2 are also a positive indications that HCl is being removed.  However, we are not proposing this because we have no data to demonstrate a direct link between HCl emissions and SO2 emissions.  For example, if a source has a scrubber-equipped kiln and notes an SO2 emissions increase, is the increase due to a drop off in scrubber performance or to an increase in sulfur compounds in the raw materials?  If it is simply a change in raw materials sulfur content, then the change may have no relevance to HCl emissions.  If the SO2 emission increase is due to a reduction in scrubber efficiency, then the change in SO2 emission might mean that HCl emission have changed.  We are requesting comment on the efficacy of using SO2 as a surrogate for HCl for purposes of monitoring compliance, and data demonstrating whether SO2 is a good surrogate for HCl for this purpose.
	One issue in using a CEMS to measure compliance with these proposed standards is whether the use of a continuous monitor results in an increase in the stringency of the standard, if that standard was developed based on short term emissions tests or other data and is a not-to-exceed standard.  Mercury data were obtained from thirty daily samples of fuel and raw materials plus statistical techniques to account for further variability in inputs, operation, and measurement.  The proposed hydrogen chloride emissions limit were derived using statistical techniques to account for variability in components such as fuel and raw material, process operation, and measurement procedures.  The proposal would require direct, continuous measurement of mercury and, for those facilities not using a wet scrubber as a control device, hydrogen chloride.  Compliance with these emissions limits for these facilities is determined by assessing the thirty day average emissions with the appropriate emissions limit.  With respect to mercury, as explained in section       above, not only do continuous monitoring and 30-day averaging accord well with the means used to gather these underlying data, but continuous monitoring and 30-day averaging are needed because cement kilns do not emit mercury in relatively equal amounts day-by-day but, due to the mill-on/mill-off phenomenon, in varying small and large amounts.  With respect to hydrogen chloride, use of a thirty day average provides a way to account for the potential short term variability inherent in values obtained from continuous data collection and analysis, so that CEM-based compliance, in combination with 30-day averaging, does not make the proposed standard more stringent than a not-to-exceed standard based on stack testing. Therefore, subject to consideration of public comment, we believe the use of continuous monitoring techniques for mercury and HCl, in combination with 30-day averaging times, is appropriate.
G.	Selection of Compliance Dates
	For existing sources we are proposing a compliance date of 3 years after the promulgation of the new emission limits for mercury, THC, PM, and HCl take effect.  This is the maximum time period allowed by law.  See section 112(i)(3)(A).  We believe a 3 year compliance period is justified because most facilities will have to install emissions control devices (and in some cases multiple devices) to comply with the proposed emissions limits.
	In the December 2006 rule amendments we included operating requirements relating to the amount of cement kiln dust wasted versus dust recycled, and also a requirement that the source certify that any fly ash used as a raw material did not come from a boiler using sorbent to remove mercury from the boiler's exhaust.  The removal of these requirements would take effect once the affected source is required to comply with a numerical mercury limit.
	For new sources, the compliance date will be the date of publication of the final rule or startup, whichever is later.  In determining the proposal date that determines if a source is existing or new, we are retaining the date of December 5, 2005 for HCl, THC, and mercury, i.e., any source that commenced construction after December 5, 2005, is a new source for purposes of the emission standards changed in these amendments.  For PM, we are proposing that the date that determines if a source is existing or new will be [INSERT THE DATE OF PUBLICTION OF THESE AMENDMENTS IN THE FEDERAL REGIATER].
	In proposing this determination, we considered three possible dates, including March 24, 1998; December 5, 2005; and the proposal date of these amendments.  Section 112 (a) (4) of the Act states that a new source is a stationary source if "the construction or reconstruction of which is commenced after the Administrator first proposes regulations under this section establishing an emissions standard applicable to such source".  "First proposes" could refer to the date EPA first proposes standards for the source category as a whole, or could refer to the date the agency first proposes standards under a particular rulemaking record.  The definition is also ambiguous with regard to whether it refers to a standard for the source as a whole, or to a HAP-specific standard (so that there could be different new source standards for different HAP which are regulated at different times).
      We believe that the section 112 (a)(4) definition can be read to apply pollutant-by-pollutant, and that the provision applies to the rulemaking record under which a standard is developed.  The evident intent of the definition plus the substantive new source provisions is that it is technically more challenging and potentially more costly to retrofit a control system to an existing source than to incorporate controls when a source is initially designed.  Consequently, new source standards should apply to sources which are being newly constructed or reconstructed in fact. See 71 FR at 76540-541.  If, for example, we were to choose March 24, 1998, as the date to delineate existing versus new sources, then numerous kilns that would be required to meet new source standards would have to retrofit controls that they could not have reasonably anticipated at the time the source was originally designed.
      We also considered selecting the proposal date of these amendments as the date that delineates new and existing sources but, for HAP other than PM, rejected that option.  The mercury and THC standards being proposed here arise out of the rulemaking proposed on December 5, 2007.   This notice is issued in response to petitions for reconsideration of the standards from that rulemaking. The proposed standard for HCl likewise arises out of the December 2007 rulemaking and its reconsideration, and EPA proposed standards for HCl in that rulemaking.  See 70 FR at 72335-37.  Thus, it is reasonable to view the December 2005 proposal as the date on which EPA first proposed standards for HCl as part of this rulemaking.
      For PM, the choices are the 1998 date on which EPA proposed PM standards, or the date of this proposal (the first date EPA proposed revision to the PM standard, based on a new rulemaking record). Subject to consideration of public comment, we believe the appropriate date is the date of this proposal.  See 71 FR at 76540-41 (applying new source standards to sources which began operation many years in the past is inconsistent with idea that new source standards may be more stringent because they can be implemented at time of initial design of the source, thus avoiding retrofit expense).
      We are establishing a compliance date for the THC emissions limit for new sources as December 21, 2009 or the effective date of these amendments, whichever is later.  A new source which commenced construction after December 2, 2005 and before December 20, 2006 would have three years from the date of publication of the final amendments to comply.  See section 112(i)(2).
H. Discussion of EPA's Sector Based Approach for Cement Manufacturing
What is a Sector-Based Approach?
	Sector-based approaches are based on integrated assessments that consider multiple pollutants in a comprehensive and coordinate manner to manage emissions and CAA requirements.  One of the many ways we can address sector-based approaches is by reviewing multiple regulatory programs together whenever possible. This approach essentially expands the technical analyses on costs and benefits of particular technologies, to consider the interactions of rules that regulate sources.  The benefit of multi-pollutant and sector-based analyses and approaches include the ability to identify optimum strategies, considering feasibility, costs, and benefits across all pollutant types  -  criteria, toxics and others -- while streamlining administrative and compliance complexities and reducing conflicting and redundant requirements, resulting in added certainty and easier implementation of control strategies for the sector under consideration.
Portland Cement Sector-Based Approach
	Multiple regulatory requirements currently apply to the cement industry sector. In order to benefit from a sector-based approach for the cement industry, EPA analyzed how the NESHAP under reconsideration relates to other regulatory requirements currently under review for portland cement facilities. The requirements analyzed affect HAP and/or criteria pollutant emissions from cement kilns and cover the NESHAP reconsideration, area source NESHAP, NESHAP technology review and residual risk, and the New Source Performance Standard (NSPS) revision. The results of our analyses are described below.
	The first relationship is the interaction between the NESHAP THC standard and the co-benefits for VOC and carbon monoxide (CO) control. The THC limit for new sources in the NESHAP will also control VOC and CO to the limit of technical feasibility.  For this reason the proposed NSPS relies on the THC NESHAP limit for new sources to represent best demonstrated technology (BDT) for VOC and CO for this source category.  See 73 FR 34082.
	Another interaction relates to the more stringent PM emission limit being proposed under the NESHAP reconsideration.  As noted, there is a legal requirement to regulate listed urban HAP metals from area source cement kilns under section 112(c)(3), and we are proposing PM standards for area source cement kilns pursuant to that obligation.  In addition, we are required under CAA section 112(f) to evaluate the residual risk for toxic air pollutants emitted by this source category and to perform a technology review for this source category under section 112(d)(6). Revisions to the PM standard for new and existing major sources under the NESHAP will maximize environmental benefits due to the achievement of greater PM emission reductions and will also reduce the possibility for additional control requirements as we consider the implication these revisions have in developing future requirements under residual risk and technology review increasing certainty to this sector.
	To reduce conflicting and redundant requirements for the cement industry regarding the control of PM emissions, EPA is proposing to place language in both the NESHAP and the NSPS making it clear that if a particular source has two different requirements for the same pollutant, they are to comply with the most stringent emission limit, and are not subject to the less stringent limit.
	Another issue being addressed as part of our cement sector strategy is condensable PM.  Particulate emissions consist of both a filterable fraction and a condensable fraction. The condensable fraction exists as a gas in an exhaust stream and condenses to form particulate once the gas enters the ambient air.  In this rulemaking, AP-42 emission factors were used to calculate emission reductions of PM2.5 filterable due to the PM standard.  There are insufficient data to assess if the cement industry is a significant source of condensable PM. The measurement of condensable PM is important to EPA's goal of reducing ambient air concentrations of PM2.5.  While the Agency supports reducing condensable PM emissions, the amount of condensable PM captured by Method 5 (the PM compliance test method specified in the NSPS) is small relative to methods that specifically target condensable PM, such as Method 202 (40 CFR part 51, Appendix M). Since promulgation of Method 202 in 1991, EPA has been working to overcome problems associated with the accuracy of Method 202 and plans to promulgate improvements in the future. In order to assist in future sector strategy development, we are considering any data available on the levels of condensable PM emitted by the cement industry; any condensable PM emission test data collected using EPA Conditional Method 39, EPA Method 202 (40 CFR part 51, Appendix M), or their equivalent, factors affecting those condensable PM emissions, and potential controls.

	Another benefit of evaluating regulatory requirements across pollutants in the context of a sector approach is addressing the relationship between the regulatory requirements for SO2, mercury, and HCl emissions.  Although SO2 emission reductions would be required in the proposed NSPS, mercury and HCl emissions reduction are required in the Portland Cement NESHAP reconsideration.  The integrated analysis of these regulatory requirements showed that alkaline wet scrubbers achieve emission reductions for SO2, mercury, and HCl from cement kilns.  This control technology maximizes the co-benefits of emission reductions while minimizing cost. For example, a new facility that under the NSPS determines a moderate level of SO2 reduction might consider using a lime injection system because it is lower cost. However, if the same facility would have to use some type of add-on control to meet the NESHAP new source mercury and/or HCl emission limits, instead of considering each standard in isolation, would determine that the cheapest overall alternative might be to use a wet scrubber for controlling SO2, mercury, and/or HCl. By coordinating requirements at the same time, the facility can determine which control technology minimizes the overall cost of air pollution control and can avoid stranded costs associated with piecemeal investments in individual control equipment for SO2, mercury, and/or HCl.
	The integrated sector-based analysis for the cement industry also showed that SO2 emission reductions from existing sources are possible as co-benefits if wet scrubbers are employed to control either mercury and/or HCl from existing sources under the NESHAP. We evaluated the co-benefits of the use of wet scrubbers in reducing SO2 and the effects on PM2.5 and PM2.5 nonattainment areas (NAA), including the co-benefits of reducing SO2 in mandatory Federal Class I areas (Class I areas).
	Another interaction addressed in the context of the sector approach is monitoring requirements.  To ensure that our sector strategy reduces administrative and compliance complexities associated with complying with multiple regulations, our rulemaking recognizes that where monitoring is required, methods and reporting requirements should be consistent in the NSPS and NESHAP where the pollutants and emission sources have similar characteristics.
New Source Review and the Cement Sector-based Approach
	The proposed MACT requirements for cement facilities have a potential to result in emissions reductions of air pollutants that are regulated under the CAA's major new source review (NSR) program.  Specifically, operating a wet scrubber to meet MACT requirements for mercury and/or HCl at a portland cement plant has the added environmental benefit of reducing large amounts of SO2, a regulated NSR pollutant.  For a typical wet scrubber, with a 90 percent removal efficiency for SO2, this could result in an annual reduction of thousands of tons of SO2 from an uncontrolled kiln (reduction will vary greatly depending on the type and age of the kiln, sulfur content of feed materials, and fuel type).  These collateral SO2 and other criteria pollutant emissions reductions resulting from the application of MACT may be considered for "netting" and "offsets" purposes under the major NSR program.
	The term "netting" refers to the process of considering certain previous and prospective emissions changes at an existing major source over a contemporaneous period to determine if a "net emissions increase" will result from a proposed modification.  If the "net emissions increase" is significant, then major NSR applies.  Section 173(a)(1)(A) of the Act requires that a major source or major modification planned in a nonattainment area obtain emissions offsets as a condition for approval.  These offsets are generally obtained from existing sources located in the vicinity of the proposed source and must offset the emissions increase from the new source or modification and provide a net air quality benefit.
	An emissions reduction must be "surplus," among other things, to be creditable for NSR netting and offset purposes.  Typically emission reduction required by the CAA are not considered surplus.  For example, emissions reductions already required by an NSPS, or those that are relied upon in a State implementation plan (SIP) for criteria pollutant attainment purposes (e.g., Reasonable Available Control Technology, reasonable further progress, or an attainment demonstration), are not creditable for NSR offsets (or netting) since this would be "double counting" of the reductions.  Also, any emissions reductions already counted in previous major modification "netting" may not be used as offsets. However, emissions reductions that are in excess of, or incidental to the MACT standards, are not precluded from being surplus even though they result from compliance with a CAA requirement.  Therefore, provided such reductions are not being double counted, they may qualify as surplus and can either be used either as netting credits at the source or be sold as emissions offsets to other sources in the same non-attainment area provided the reductions meet all other otherwise applicable CAA requirements for being a creditable emission reduction for use as an offset or for netting purposes.
	Since SO2 is presumed a PM2.5 precursor in all prevention of significant deterioration and nonattainment areas unless a state specifically demonstrates that it is not a precursor, SO2 may be used as a emission reduction credit for either SO2 or PM2.5, at an offset ratio is 40-to-1 (40 tons of SO2 to 1 ton of PM2.5) See 72 FR 28321-28350 (May 16, 2008).
	Given that many states have concerns over a lack of direct PM2.5 emissions offsets for areas that are designated nonattainment for PM2.5, cement plants that generate creditable reductions of SO2 from applying MACT controls may realize a financial benefit if they can sell the emissions credits as SO2 and/or PM2.5 offsets.  While it is difficult to quantify the exact financial benefit, since offset prices are market driven and vary widely the U.S., we know that prices for PM2.5 emissions credits can reach $40,000 in some nonattainment areas, and may still be higher in others.  For the sake of approximation, using $20,000 for an average price per ton of a PM2.5  offset, a cement plant that creates a 2,000 tons per year reduction in SO2 can potentially sell the emissions credits for as much as $1,000,000 per year (i.e., 2000 tpy / 40_ratio x $20,000/ton), as long as the reductions are creditable and surplus.
National Ambient Air Quality Standards
	Portland cement kilns emit several pollutants regulated under the NAAQS, including PM2.5, SO2, NOx, and precursors to ozone.  In addition, several pollutants emitted from cement kilns are transformed in the atmosphere into PM2.5, including SO2, NOx, and VOC.  Emissions of NOx and VOC are also precursors to ozone.  Thus, implementation of the Cement NESHAP, which could lead to substantial reductions in criteria pollutants and precursor emissions as co-benefits, could help areas around the country attain the NAAQS.
	Screening analyses showed that 23 cement facilities were located in 24hr PM2.5 NAA and 39 facilities in Ozone NAA.  Control strategies for reducing emissions of THC, mercury, HCl, and PM from cement plants under the Cement NESHAP have the co-benefits of reducing SO2 and direct PM2.5 emissions.  These co-benefits could provide states with emission reductions for areas required to have attainment plans.
Regional Haze, Reasonable Progress, and the Cement Sector-based Strategy
	The Cement NESHAP can also have an impact on regional haze.  Under section 169A of the CAA, States must develop SIPs to address regional haze.  The purpose of the regional haze program is the prevention of any future, and the remedying of any existing, impairment of visibility in mandatory Class I areas which impairment results from manmade air pollution Under the regional haze regulations, the first Regional Haze SIPs were due in December, 2007 (40 CFR 51.308(b)); these SIP submittals must address several key elements, including Best Available Retrofit Technology (BART), Reasonable Progress, and long-term strategies.  Screening analyses showed that there are 14 cement facilities within a distance of 50 km Class 1 Areas.
	A potential benefit for cement facilities utilizing wet scrubbers to comply with this rule is a level of certainty for satisfying a facility's BART requirements for SO2 under the regional haze program.  This rule may establish a framework for States to include certain control measures or other requirements in their regional haze SIPs where such a program would be "better than BART."  A facility must comply with BART as expeditiously as practicable but no later than 5 years after the regional haze SIP is approved.  A state may be able to rely on this rule to satisfy the BART requirements for a NESHAP affected source utilizing a wet scrubber if (1) the compliance date for a source subject to this NESHAP falls within the BART compliance timeframe, (2) the proposed controls are more cost effective than the controls that would constitute BART, and (3) the visibility benefits of the controls are at least as effective as BART.
	States may also allow sources to "average" emissions across any set of BART-eligible emissions units within a fence-line, provided the emissions reductions from each pollutant being controlled for BART are equal to those reductions that would be obtained by simply controlling each of the BART-eligible units that constitute the BART-eligible source (40 CFR 51.308(e)(2)). This averaging technique may also be advantageous to cement facilities subject to this NESHAP that also have BART-subject sources.
	Under the regional haze rule, States may develop an alternative "better than BART" program in lieu of source-by-source BART.  The alternative program must achieve greater reasonable progress than BART would toward the national visibility goal.  The alternative program may allow more time for compliance than source-by-source BART would have allowed.  Any reductions relied on for a better than BART analysis must be surplus as of the baseline year the State relies on for purposes of developing its regional haze SIP (i.e., 2002) and can include reductions from non-BART and BART sources.  Visibility analyses must verify that the alternative program, on average, gets greater visibility improvement than BART and that no degradation in visibility on the best days occurs (40 CFR 51.308(e)(3)).
	EPA believes that emissions units at cement sources found to be subject to BART and that will be required to install controls or otherwise achieve emissions reductions per the regional haze regulations can benefit from this Cement NESHAP to potentially satisfy the regional haze requirements.  EPA will need to demonstrate that the implementation of the cement NESHAP will result in SO2 emissions reductions and related visibility improvements that are greater than reductions achieved through the application of BART controls.  If EPA demonstrates that the SO2 emissions reductions and visibility and air quality improvements resulting from the rule are better than BART, this demonstration, when incorporated into the Regional Haze SIP, is anticipated to fulfill federal regulatory requirements associated with BART requirements for cement facilities.
	Additionally, the level of control achieved through the Cement NESHAP may contribute toward, and possibly achieve, the visibility improvements needed to satisfy the reasonable progress requirements of the regional haze rule for cement facilities through the first Regional Haze planning period.  States can submit the relevant regional haze SIP amendments once this rule becomes final.
Health Benefits of Reducing Emissions from Portland Cement Kilns
	Implementation of the Cement NESHAP, which could lead to substantial reductions in PM2.5, SO2, and toxic air pollutants, could reduce numerous health effects.
	Section VI.J of this preamble provides a summary of the monetized human health benefits of this proposed regulation based on the Regulatory Impact Analysis available in this docket that includes more detail regarding the costs and benefits of this proposed regulation.
	As mentioned before, portland cement kilns emit several pollutants with known human health effects, including PM2.5, SO2, NOx, and precursors to ozone. Exposure to PM2.5 is associated with significant respiratory and cardiac health effects, such as premature mortality, chronic bronchitis, nonfatal heart attacks, hospital admissions, emergency department visits, asthma attacks, and work loss days. USEPA, Air Quality Criteria for Particulate matter, chapter 9.2 (October 2004).  Exposure to SO2 and NOx is associated with increased respiratory effects, including asthma attacks, hospital admissions, and emergency department visits.  Exposure to ozone is associated with significant respiratory health effects, such as premature mortality, hospital admissions, emergency department visits, acute respiratory symptoms, school loss days.
	In addition, portland cement kilns emit toxic air pollutants, including mercury and HCl.  Exposure to high levels of mercury is associated with central nervous system damage, kidney damage, blindness, deafness, speech difficulties, and developmental effects.  Acute inhalation exposure to hydrochloric acid is associated with irritation of mucous membranes, inflammation, and fluid accumulation in the lungs.
	We welcome comments and suggestions related the interactions of this proposed NESHAP and other regulatory requirements in the context of the sector-based considerations described above.

I.	Other Changes and Areas Where We are Requesting Comment
Startup, Shutdown and Malfunction.  The
       Court of Appeals for the District of Columbia Circuit recently vacated EPA's rules exempting major sources from otherwise applicable emission standards during periods of startup, shutdown and malfunction.  Sierra Club v. EPA, F.3d (2008).  A consequence is that
      EPA must develop section 112(d) standards for these operating conditions for previously-exempted major sources.  Portland cement kilns are among these previously-exempted source categories.  For purposes of this proposed rule, this means that that these sources must now either meet generally applicable emission standards at all times, or EPA must develop section 112 (d) standards for cement kilns when operating under startup, shutdown or malfunction conditions.
      EPA is not now at a point where it can propose quantitative standards for cement kilns operating in startup, shutdown and malfunction modes.  Accordingly, the Agency solicits comment, including available data, addressing this issue.  In addition, there is likely to be a difference in standards depending on which of the modes is at issue.  Startup
       and shutdown are both somewhat controlled operating modes for cement kilns (although occurring over different time periods), though we believe that shutdowns can vary (planned or emergency) and startups can be from a cold or a hot kiln.  Malfunction conditions are (by definition) unanticipated occurrences for which control strategies are mainly reactive.  EPA thus
       requests that commenters differentiate among the five operating modes in addressing this issue.  EPA notes further that it may notice data received on this issue for further public comment as part of this rulemaking.
	Data used to set existing source floors.  The emissions standards included in the proposed rule were calculated using the emissions information available to the Administrator, in accordance with EPA's interpretation of the requirements of section 112(d)(3) of the Act.  In developing this proposed rule, we specifically sought data from as many kilns as possible given the time constraints when we began our data collection process.  Given that there are 152 kilns in this source category, the 12 percent representing the best performing kilns would be 19 kilns.  However, in some cases we have emission data from as few as 12 cement kilns, which means that existing source floors were proposed using as few as 2 kilns (although we are soliciting comment on an alternative interpretation that would allow EPA to base floors on a minimum of five sources' performance in all instances where those data exist.  EPA knows that more emissions information from other kilns, both with and without similar process and control characteristics, would lead to a better characterization of emissions from the entire population of cement kilns, as well as a better description of intra-source, inter-source, and test method variability, and that statistical techniques can be employed to provide the expected distribution of emissions for the cement kiln population.  EPA thus requests commenters to provide additional emissions information on cement kilns' performance.
	HCl Test Data and Methods.  In some instances, the emissions standards included in the proposed rule were calculated using emissions information provided to EPA that appears to be below detection levels established more than 15 years ago.  More specifically, Method 321 identifies a practical lower quantification range for hydrogen chloride from 1000 to 5000 parts per billion for a specific path length and test conditions.  Many of the best performing sources with respect to HCl emissions report both values and detection levels below 1000 parts per billion.  While it is not surprising that detection levels should decrease as improvements in analytical methods occur over time, EPA does not have the emissions information and other data necessary to assess independently the new, lower detection levels, some as low as 20 parts per billion.
	Without additional data or detection limit calculations, EPA could maintain the old detection limit, accept the source-provided limit, or modify the source-provided limit to an expected new acceptable level.  Selection of an appropriate detection limit is no trivial matter, as the detection limit could impact how the available data would be used in average emissions calculations.  EPA could choose not to use any data below the detection limit in calculations.  EPA could also choose to set all data below the detection limit at a value corresponding to one-half the detection limit for average calculation purposes, reasoning that any amount of emissions between zero and the detection limit could occur when the detection limit is recorded.  Indeed, this approach, setting all data below the detection limit at a value corresponding to one-half the detection limit, was chosen by the sources that provided emissions information to EPA.  EPA could also set all data below the detection limit at a value corresponding to the detection limit, or to zero, for average calculation purposes.  Finally, EPA could apply statistical techniques to available emissions information both above and below the detection limit to provide the expected distribution of HCl emissions for the cement kiln population.  A further issue, with any of these possible approaches, would be to assess sources' operating variability.
	EPA based the HCl emissions limitations contained in the proposal using the source-provided detection limits and setting all data below the detection limit at a value corresponding to one-half the detection limit for average calculation purposes.  This approach is consistent with the emissions information supplied by sources to EPA.  See also Rybachek v. EPA, 904 F. 2d 1276, 1296 (9[th] Cir. 1990)(upholding use of this approach in setting technology-based Clean Water Act effluent limitation guideline standards).  Should EPA receive additional emissions information sufficient to calculate detection limits from already-received data or emissions information including detection limit calculations from other sources, EPA would be able to ascertain and revise, if necessary, the new detection limits and to calculate a different HCl standard.
	EPA requests additional HCl emissions information, including such information as needed to calculate detection limits, as well as detection limit calculations.  Moreover, EPA requests comments on which way, if any, to set the emission detection limit and to handle emissions information below the detection limit are suitable for use in this proceeding.  For those commenters who believe EPA's proposed emission detection limit and process to handle values below the detection limit may not be suitable, EPA requests commenters to provide their views of acceptable detection limits and processes that use values below the detection limits to calculate averages, as well as examples of sample calculations using those processes.  We are also requesting comment on the same issues relating to the use of a CEMS meeting the requirements of PS-15 to measure HCl emissions.

	Submission of Emissions Test Results to EPA.  Compliance test data are necessary for many purposes including compliance determinations, development of emission factors, and determining annual emission rates.  EPA has found it burdensome and time consuming to collect emission test data because of varied locations for data storage and varied data storage methods.
      One improvement that has occurred in recent years is the availability of stack test reports in electronic format as a replacement for burdensome paper copies.
	In this action, we are taking a step to improve data accessibility for stack tests (and in the future continuous monitoring data).  Portland cement sources will have the option of submitting to WebFIRE (an EPA electronic data base), an electronic copy of annual stack test as well as process data.  Data entry requires only access to the Internet and is expected to be completed by the stack testing company as part of the work that they are contracted to perform.  This option would become available as of December 31, 2011.
	Please note that the proposed option to submit source test data electronically to EPA would not require any additional performance testing.  In addition, when a facility elects to submit performance test data to WebFIRE, there would be no additional requirements for data compilation; instead, we believe industry would greatly benefit from improved emissions factors, fewer information requests, and better regulation development as discussed below.  Because the information that would be reported is already required in the existing test methods and is necessary to evaluate the conformance to the test method, facilities would already be collecting and compiling these data.  One major advantage of electing to submit source test data through the Electronic Reporting Tool (ERT), which was developed with input from stack testing companies (who already collect and compile performance test data electronically), is that it would provide a standardized method to compile and store all the documentation required by this proposed rule.  Another important benefit of submitting these data to EPA at the time the source test is conducted is that it will substantially reduce the effort involved in data collection activities in the future. Specifically, because EPA would already have adequate source category data to conduct residual risk assessments or technology reviews, there would be fewer data collection requests (e.g., section 114 letters).  This results in a reduced burden on both affected facilities (in terms of reduced manpower to respond to data collection requests) and EPA (in terms of preparing and distributing data collection requests).  Finally, another benefit of electing to submit these data to WebFIRE electronically is that these data will greatly improve the overall quality of the existing and new emissions factors by supplementing the pool of emissions test data upon which the emission factor is based and by ensuring that data are more representative of current industry operational procedures.  A common complaint we hear from industry and regulators is that emissions factors are out-dated or not representative of a particular source category. Receiving most performance test results would ensure that emissions factors are updated and more accurate.  In summary, receiving these test data already collected for other purposes and using them in the emissions factors development program will save industry, State/local/tribal agencies, and EPA time and money.
	As mentioned earlier, the electronic data base that will be used is EPA's WebFIRE, which is a Web site accessible through EPA's TTN. The WebFIRE Web site was constructed to store emissions test data for use in developing emission factors. A description of the WebFIRE data base can be found at http://cfpub.epa.gov/ oarweb/index.cfm?action=fire.main.  The ERT will be able to transmit the electronic report through EPA's Central Data Exchange (CDX) network for storage in the WebFIRE data base.  Although ERT is not the only electronic interface that can be used to submit source test data to the CDX for entry into WebFIRE, it makes submittal of data very straightforward and easy.  A description of the ERT can be found at http://www.epa.gov/ttn/chief/ert/ ert_tool.html.  The ERT can be used to document the conduct of stack tests data for various pollutants including PM (EPA Method 5 of appendix A - 3), Mercury (EPA Method 29 of appendix A - 8), and HCl (EPA Method 321 of appendix A - 8).  Presently, the ERT does not handle dioxin/furan stack test data (EPA Method 23 of appendix A - 7), but the tool is being upgraded to handle dioxin/furan stack test data.  The ERT does not currently accept opacity data or CEMS data.
	EPA specifically requests comment on the utility of this electronic reporting option and the burden that owners and operators of portland cement facilities estimate would be associated with this option.
	Definition of affected source.  In the final amendments published on December 20, 2006, we indicated that we were changing paragraph (c) in §63.1340 to clarify that crushers were part of the affected source for this rule (71 FR 76532).  However, we omitted the rule language changes to that paragraph.  This language has been added to this proposed rule.
V.  Summary of Comments and Responses on Notice of Reconsideration and EPA Final Action in Response to Remand
	This section presents a summary of
	comments received on the final action published on December 20, 2006.
	We are not responding to these comments in this proposed action.  We will provide responses to these comments, and other comments received on these proposed amendments, when we take final action on this proposal.
A.  Petition to Withdraw Final Standards
	Commment:  One commenter petitioned EPA to withdraw the new source standards for mercury and THC, as well as the provision in §63.1344(i) concerning the allowable CKD recycle rate because of procedural defects and the lack of record support.  Several commenters agree that EPA should withdraw the standards for the same reasons given in the petition.
	The commenter stated that the proposed rule was silent on the possibility of issuing a new source standard for mercury based on a wet scrubber, a new source standard for THC based on an RTO, and the operating limit for new and reconstructed kilns in §63.1344(i).  EPA violated CAA section 307(d)(3) and (d)(5) by not proposing these requirements and not providing an opportunity for comment.  The commenter also alleged that comments filed by the public did not lead EPA to the positions taken in the final rule.  Therefore, EPA cannot argue that the final standards represent a "logical outgrowth" of the proposal.
	EPA application of the reconsideration process does not cure these defects.  EPA lacks authority to initiate reconsideration on its own through CAA section 307(d)(7)(B); this provision clearly is designed for a process in response to request by another person.  There appears to be no precedent for this action and EPA did not cite any precedent.
	The commenter also argued that the standards lack record support and are therefore arbitrary and capricious under CAA section 307(d)(9)(A).  EPA conceded in the final rule and notice of reconsideration that it was unclear whether the new source standards for mercury and THC are "achievable" or appropriate (see pages 12-14).  For the provision concerning the CKD recycle rate, EPA provided no explanation as to whether it was possible to continually "not exceed the average hourly CKD recycle rate during mercury performance testing" or whether any cement kiln has achieved this result in practice.  Because EPA did not point to any "best controlled" existing source that has achieved such a recycle rate, the provision violates the MACT floor requirements for new sources in CAA section 112(d)(3).  EPA in effect promulgated a beyond the floor standard without considering the required criteria (including costs) in CAA section 112(d)(2).  EPA also did not demonstrate that the requirement is achievable, did not provide a "statement of basis and purpose" for the requirement, or an explanation of the reasons for changes from the proposal in this regard, as required by CAA section 307(d)(6)(A).
  	According to the commenter, EPA's promulgation of these standards, coupled with the notice for reconsideration, has created significant uncertainty and will require construction delays until the issues are resolved or installation of the technologies regardless of whether they are necessary; either will result in financial harm to several companies.
B.  Petition to Reconsider Final Standards
	One commenter petitioned EPA to reconsider the work practice standards for mercury and THC, the decision not to set standards for HCl, and the decisions not to set beyond-the-floor standards for mercury and THC.
	Comment:  The commenter argued that the work practice standards for mercury and THC are unlawful.  The D.C. Circuit Court remanded the cement kiln rule with instructions to set MACT floor standards for HCl, mercury, and THC.  However, EPA set work practice standards instead of emission standards.  The commenter asserted that the work practice standards are not and do not purport to be emission standards.  The CAA makes it entirely clear that for the purpose of section 112, a work practice standard is not an emission standard.  Section 112(h) provides that "if it is not feasible ... to prescribe or enforce an emission standard for the control of a hazardous air pollutant or pollutants, the agency may in lieu thereof, promulgate a design, equipment, work practice, or operational standard . . ."  The clarity of section 112 on this point is not diminished by section 302(k)'s definition of "emission standard" to include a work practice standard.  Section 112(h) is the more specific provision with respect to section 112 standards.  Reading "emission standard" to include work practice standards would nullify the distinction that section 112(h) draws between the two, and essentially render section 112(h) meaningless and surplus.  Because the only requirements EPA established for emissions of mercury and THC from existing kilns are work practice standards rather than emission standards, the final rule violates National Lime's mandate to set emission standards.  The commenter also argues that the work practice standards, if they could be viewed as emission standards, do not satisfy the MACT floor requirements in section 112(d)(3); EPA did not purport the work practices reflect the relevant best sources' emission levels or the best performing 12 percent of kilns, which EPA has never identified.  The commenter also stated that the work practices do not satisfy section 112(h) because EPA did not claim that was not feasible to prescribe or enforce an emission standard for either pollutant.  EPA could not make this claim because both pollutants are emitted from kiln stacks and it is technologically or economically impractical to measure the emissions.
	Comment:  The commenter alleges that EPA's refusal to set any emission standards for HCl is unlawful.  The commenter claimed that section 112(d)(4), which EPA cited as its authority for declining to set emission standards for HCl, does not excuse EPA from setting standards for a pollutant but merely provides that it is there as an established health threshold for a pollutant, EPA may consider that threshold, with an ample margin of safety when establishing emission standards.  According to the commenter, EPA confirmed that it did not know whether or not HCl causes cancer.  Because EPA does not know whether HCl is carcinogenic, EPA has not identified a health threshold below which HCl does not cause cancer.  Therefore, EPA can not invoke section 112(d)(4) with respect to HCl.  The commenter also stated that EPA's attempts to rely on its statements about HCl in previous rules are unfounded.  The 1998 rule on which EPA primarily relies classified HCl as a Group D pollutant (one for which EPA lacks data about carcinogenicity).  Classification of a pollutant in Group D merely underscores that EPA cannot support a finding that a pollutant is a threshold pollutant with respect to cancer.  In addition, the 1998 rule made the Group D classification only for the purposes of that rule and not for any other actions.
The commenter also pointed out that EPA has not identified a threshold for non-cancer effects.  The threshold EPA claimed to have identified as the reference dose concentration (RfC), i.e., the long term threshold, must be a level below which no adverse health effects occur.  The level that EPA claims is a threshold does not meet this requirement because it was based on a single animal study which used only one dose, looked only at respiratory effects, not effects on other bodily systems, and identified only a lowest observed adverse effects level at which adverse effects did occur, not a threshold at which adverse effects do not occur.  The commenter stated that EPA effectively acknowledged that exposure to HCl does damage people's heath (71 FR 76542).  Congress intended EPA to apply section 112(d)(4) where there is no risk of adverse health effects.  Tissue damage is an adverse health effect.
The commenter stated that EPA's reliance on a risk assessment prepared by an industry trade association is unlawful and arbitrary.  The record does not show any attempt to verify the data, methodology, or results and the analysis gives no indication when the data was obtained, whether it reflects ongoing conditions, whether it accounts for potential emissions and modifications, whether the assumptions and emissions levels in the analysis are representative, or why one-third of the plants are not included.  The commenter also argued that analysis did not adequately show that HCl emissions from the kilns covered by study are below the RfC.  According to the commenter, the analysis uses default rather than kiln-specific data for all but one variable to estimate HCl emissions and concentrations.  Even if the study showed conclusively that HCl levels were at or below the RfC, the absence of data and mischaracterization of background levels prevents EPA from showing that it has provided an ample margin of safety as required by CAA section 112(d)(4).  According to the commenter, the analysis mischaracterized background emissions and provides no reason to believe that HCl background levels in areas where kilns operate is not higher or that background levels have not increased compared to 1996 and 1999 values, does not account for variability, and does not adequately account for co-location of industrial facilities.  The analysis of background levels for short-term hazard quotient is similarly flawed.  The commenter also criticized the application of a rural parameter to all kilns, which is not the case for many kilns.
Section 112(d)(4) also requires that the standards do not have any adverse environmental effects.  No ecological assessment was conducted for the analysis or by EPA.  In fact, the analysis does not even claim there would be no impacts, only that any deleterious effects were likely to be localized rather than widespread.
	Comment:  The commenter criticized EPA's beyond-the-floor determination for mercury emissions.  According to the commenter, EPA conducted beyond-the-floor analyses for all "demonstrated" control techniques excluding all of the techniques raised in public comments except for ACI and wet scrubbers.  EPA's claim that it can ignore technologies if the Agency does not believe that they are "demonstrated control techniques for the cement industry" is unlawful.  Section 112(d)(2) requires beyond-the-floor standards to reflect the maximum degree of reduction that is achievable through the full range of potential reduction measures.  There is no precondition that control technologies must be demonstrated in the industry to be regulated.
	EPA's rejection of ACI as not cost-effective based on new cost estimates is unlawful and arbitrary for all the reasons given in comments on the proposed rule.  EPA's rejection of ACI is also unlawful and arbitrary because:  (1)  EPA alludes to increased energy use but does not say what increase would occur and why that justifies rejection of ACI; and (2)  EPA alludes to increased solid waste generation, but does not say why the specific amount generated weighs against beyond-the-floor standards or why it is preferable for mercury to be emitted to the air rather than contained in solid waste.  The Agency must explain the relevance of a specific statutory factor to beyond the floor analysis and how consideration of that factor supports its conclusion.
	Although EPA acknowledged that ACI reduces THC, the cost effectiveness analysis remains arbitrary because EPA never determined the cost effectiveness of ACI with respect to all the HAP it controls (including polychlorinated biphenyls, polycyclic organic matter, and benzene).  Further, the analysis mistakenly assumes that the same ACI device would have to be purchased separately with respect to each HAP, when the device is a single investment that would reduce many pollutants.  In addition, EPA did not explain why it considers the amount of THC that would be reduced as "small" (30 to 117 tpy per kiln is significant) or why such a reduction is not justified.  Finally, EPA's claim that it can reject a beyond-the-floor measure, not because the measure is not "achievable", but because it does not view the cost as "justified" is unlawful for the reasons given in previous comments.
	Comment:  EPA's rejection of a beyond-the-floor standard banning the use of utility boiler fly ash where such use increases mercury emissions is unlawful and arbitrary.  EPA claims that this measure is not "justified" because of cost, energy, and non-air environmental impacts.  The CAA requires EPA to set final standards reflecting the maximum degree of reduction that is "achievable" considering costs and other factors, not the degree of reduction that EPA thinks is "justified" in light of those factors.  And, because EPA admitted that it did not know what the costs of this measure would be, reliance on cost arguments to reject the provision is arbitrary.  Also arbitrary is EPA's reliance on non-air impacts (the increased amount of utility boiler ash that would have to be otherwise disposed of).  EPA did not explain why:  (1)  the need for utility boilers to dispose of their ash would be a worse problem than the release to the air of the mercury contained in the ash; (2) all the ash that is currently used in kilns would require disposal when it can be used in concrete without going to the kiln; (3)  kilns that are currently using fly ash would have to use raw materials if the use of fly ash that increases mercury emissions were banned; (4)  the undetermined amount of mining necessary for an undetermined number of kilns that had to stop using any fly ash would be a worse problem than the mercury emissions that result from the use of the fly ash such that the concern about additional mining weighs against the beyond the floor measure.  EPA also cites energy concerns as a reason for rejecting the beyond the floor measure but does not identify or explain them.
Comment:  The commenter criticized EPA's beyond-the-floor determination for THC emissions.  EPA rejected beyond-the-floor standards based on ACI and wet scrubbers combined with RTO (scrubber/RTO) based on the costs per ton of THC removed and organic HAP removed and alleged concerns about increased energy use and adverse non-air quality health and environmental impacts.  EPA also rejected optimized combustion practices because it lacks the data to evaluate reductions and the use of a carbon coke system because the Agency considered scrubber/RTO and therefore does not have to consider other options that are not already in use in this country.  EPA's claim that it can reject a beyond-the-floor measure not because it has determined that the measure is not "achievable" but because the cost is not justified is unlawful for the reasons given in comments on the proposed rule.  Further, EPA's contention that beyond-the-floor standards based on ACI and scrubber/RTO would not be justified on cost grounds is not explained.  The cost of reducing THC as a surrogate for all the non-dioxin organic HAP from the kilns is reasonable and well within the ranges EPA has found acceptable for other rules.  EPA can not look past the cost of the THC reduction as the reason for rejecting the measure.  If THC is not a valid surrogate, EPA should find a different surrogate or establish separate limits for each pollutant.  It is arbitrary to choose a surrogate for some purposes but not others.  In addition, EPA cost effectiveness estimates for organic HAP are unexplained, unsupported by the record, and arbitrary.  EPA did not explain its assumption that organic HAP comprise 5 percent of the THC, which organic HAP it is counting, or the quantity of emissions from these HAP.  In addition, determining the cost effectiveness of all non-dioxin organic HAP on a single cost per ton basis is not warranted because these HAP emissions vary in quantity and toxicity.  EPA also does not provide any basis for its arguments about energy use and solid waste or why these impacts make the beyond the floor measure either unachievable (the statutory standard) or unjustified (EPA's preferred standard).
	EPA's rejection of optimized combustion controls is arbitrary and unlawful.  According to the commenter, EPA argues that it does not even have to consider potential reduction measures if it does not already have data for them.  EPA cannot frustrate section 112(d)(2) requirements by declining to collect information.  Congress required the maximum degree of reduction that is achievable through all potential reduction measures, not the maximum degree of reduction achievable through measures for which the Agency deigns to collection information.
	EPA's rejection of carbon coke technology is arbitrary because the Agency provided no rationale basis for its conclusion.  EPA rejected carbon coke technology because it is used by a kiln in another country.  No language in the CAA suggests that EPA may refuse to consider a technology because it is not already in use in this country or because the Agency has considered some other technology.
C.  New Source MACT for Mercury Emissions and Related Requirements
Comment:  One commenter states that new cement kilns are not likely to install wet scrubbers in areas where the raw materials are low in sulfides.  The commenter recommends that EPA include an alternative standard for new kilns that allows the owner or operator to average mercury emissions over all modes of the raw mill operation on a monthly basis to achieve the same limit in the final rule.
	Comment:  One commenter explained that a 3 to 9 hour stack test on a cement kiln cannot provide an accurate or representative estimate of long-term mercury emissions.  The rate of mercury emissions from a modern precalciner kiln is constantly changing.  Even a 1 week test can not provide a representative picture of long-term (1 year) mercury emissions from these systems.
Comment:  One commenter asks that EPA require more representative mercury monitoring such as the periodic use of EPA Method 324 (Sorbent Trap) or mercury CEMS at all cement kilns based on their mercury emission profiles and raw material practices.
Comment:  One commenter points to high mercury emissions in 2004 with reduced emissions in 2005 from one cement plant in California and one cement plant in Oregon based on the most recent toxic release inventory submittals.  The commenter asks EPA how mercury was reduced at these sites in 2005 and how they will be reduced at these sites in the future and for EPA to determine whether the concepts used by the plants can be used in more kilns.
	Comment:  One commenter pointed out that mercury emissions from cement plants are higher than the entire mercury budgets for future coal-fired power plants emissions in numerous States.  The revisions made after reconsideration must be at least as stringent as the December 2006 final rule.  Another commenter states that EPA has not effectively controlled mercury emissions from cement kilns; new and existing kilns should have the most stringent requirements.
D.  New Source MACT for THC Emissions and Related Requirements
	Comment:  One commenter objected to the MACT floor for new kilns based on the single application of a wet scrubber and RTO.  According to the commenter, EPA stated that two facilities have attempted to use the technology; at one facility the systems did not operate continuously due to significant operational problems caused by the site specific constituents in the flue gas but the technology operates continuously and effectively at the second facility.  The commenter claimed that the standard is based on a technology that has not been demonstrated to work in all applications.  In addition, the technology at the second facility has not worked continuously and effectively as EPA claimed.  According to the commenter, the technology has experienced operational and maintenance problems at both facilities.  The commenter stated that EPA's evaluation of the MACT floor is flawed and should be reevaluated.
	Comment:  Some commenters disagreed with EPA's cost estimates for wet scrubber/RTO technology.  One commenter stated that the capital costs at the two facilities referenced by EPA for a 1 million tpy kiln are $18 to $25 million for wet scrubbers and $15 to $20 million for RTO compared to EPA's estimate of $10.7 million.
	One commenter stated that requiring the wet scrubber/RTO technologies for new sources may make new construction economically infeasible and that neither the wet scrubbing nor RTO technologies have been required based on permitting/new source review requirements.  Another commenter stated that the new source MACT requirements for THC (wet scrubber/RTO) will have a negative impact on the local watershed which can not afford the additional 58.5 million gallons of water per year for a wet scrubber.
	Comment:  One commenter alleges that EPA's statement on consultation with Indian Tribes (no tribes were consulted about the rule because it would have no impact on them) is inaccurate because the commenter is constructing a new source on the Moapa Pauite Indian Reservation.
E.  Cement Kiln Dust Requirements
	Comment:  One commenter said the CKD provision in §63.1344(h) is unworkable because it codifies as "static" a practice that varies from plant to plant.  The primary purpose of removing CKD from the kiln system is to manage the concentration of alkali compounds in the clinker and subsequent cement.  The amount of CKD removed varies according to the chemistry of the raw material feed.  In addition, alkali specifications have changed as a result of State requirements, resulting in changes in the amount of CKD removed.  And, plants that use a preheater/precalciner design do not remove CKD from the kiln system (and the material is not considered to be generated at these plants) while other plants using long dry or long wet technology remove CKD from the system but return it as a component of the raw material mix.  Another commenter explained that removing CKD from the kiln system recycling loop is critical to the efficient control of mercury emissions.
	Another commenter stated that the CKD provision, as written, could be interpreted to require removal of CKD from the system.  Unnecessary removal would create a new solid waste problem and reduced the energy efficiency of the process if the amount of raw materials going into the process had to increase as a result of the CKD being removed.
	Finally one commenter requests that EPA clarify the CKD provision for existing sources in §63.1344(h).  EPA explained in the preamble that a facility must remove CKD from the system "at the point product quality is adversely affected."  The comment asks whether "the point" is a point in time, point in the cement manufacturing process, or point on the continuum of cement product chemistry.  Also, what "product quality" standard is meant (i.e., ASTM, American Association of State Highway Transportation Officials, ANSI, or another standards organization)?  Is there a need for different compliance approaches to suit the various types of cement (e.g., Type 1, Type V) produced by an individual facility?
F.  Fly Ash Requirements
	Comment:  Some commenters urged EPA to stand by its decision not to ban all fly ash but object to the fly ash provision as promulgated.  According to the commenters, the ban could result in increased landfilling of the ash.  The prohibition was adopted without proper notice and comment and EPA adopted the ban based on consultations with one industry sector without discussing it with the sector most affected (coal burning power industry).  The commenters also disagreed with EPA's explanation that the fly ash prohibition could be imposed without any immediate impacts because utilities will not be installing ACI or other forms of sorbent injection until at least 2010.  The commenters believed that adverse effects are likely as early as 2007 when plants begin testing or plants must comply with State regulations.
	The commenters stated the prohibition was inflexible because it does not allow for exceptions regardless of the emission control technologies used at the kiln.  If there is justification for a ban on the use of mercury-enhanced fly ash in kilns with no controls, EPA failed to address the need for a ban at kilns with controls (i.e., wet scrubbers, ACI, fabric filters).  The provision allowing the kiln to demonstrate that the fly ash will not increase mercury emissions over baseline levels puts the burden and cost of testing the emissions on the cement plant.  The cement plant could easily avoid the burden by using alternative feedstock, possibly with higher mercury concentrations.  It is unrealistic to expect the cement industry to spend resources on the testing especially if the kiln already has emission controls and no testing requirements apply to any other feedstock.  EPA should amend §63.1344(g) to exclude plants already subject to a mercury standard as follows:
      No kiln and in-line kiln/raw mill may use as a raw material or fuel any fly ash where the mercury content of the fly ash has been increased through the use of activated carbon, or any other sorbent if it will result in an increase of mercury input to the process unless the facility desiring to use the fly ash is already subject to a mercury standard (either an emission or input limitation) or unless the facility can demonstrate that the use of that fly ash will not result in an increase in mercury emissions over baseline emissions (i.e., emissions not using the fly ash).  The facility has the burden of providing there has been no emissions increase over baseline.

This change would allow kilns that have installed emission controls to rely on them without additional testing, demonstrations, or certifications and would not penalize one feedstock from one industry sectors while favoring other feedstocks that may contain higher mercury concentrations.
Comment:  One commenter pointed out that the final rule includes a ban only on fly ash derived from power plants that use ACI to reduce mercury emissions.  The commenter recommends that EPA expand the scope of the limited fly ash ban to address high loss on ignition (LOI) or selective catalytic reduction (SCR)-affected fly ash laden with mercury.  Such fly ash should be treated in a like manner to ash containing activated carbon.  Expanded mercury measurement and removal strategies should be incorporated if use of such fly ash is allowed at cement plants.  The commenter provides information explaining how fly ash can become enriched with mercury due to combustion controls for nitrogen oxide (NOX) (i.e., low NOX burners, separate overfire air, reburn) and SCR.  High emissions of mercury may result from power plant fly ash where ACI is not used to control mercury emissions.
Another commenter stated that cement kilns combusting fly ash containing higher LOI fly ash after the ash has been beneficiated generally by electrostatic separation can emit higher levels of mercury.  Cement kilns are currently burning beneficiated high LOI fly ash.  Re-use of higher LOI beneficiated fly ash through combustion in cement kilns should be further evaluated.
	Comment:  One commenter objected to EPA's assumption that the TOXECON system (which collects fly ash before sorbents are injected) will work for all power plants and be economically feasible; this technology has not be tested on medium and high sulfur bituminous coal and may not be effective.  The commenter disagreed with EPA's statement in the preamble that "technology is being developed that would allow the mineral-rich portion of the fly ash to be separated from the high carbon/high mercury portion."  According to the commenter, the record does not identify these technologies by name or documents the cost.  The commenter is aware of fly ash beneficiation technologies that remove carbon from fly ash so it can be used in concrete, but it is unclear whether these technologies can remove activated carbon containing adsorbed mercury.
Comment:  Two commenters stated that the certification requirements for fly ash contaminated by activated carbon are too burdensome.  The commenters objected to the requirement in §63.1344(o) for facilities to obtain from the fly ash supplier a certification for each shipment of fly ash.  The amount of fly ash used varies considerably, but some plants receive numerous shipments on a daily basis.  The commenters recommend that the rule require each supplier to provide an initial certification confirming that the fly ash does not contain activated carbon used to capture mercury.  A new certification could be required annually or if the treatment method was changed.
G.  Compliance Dates for Cement Kiln Dust and Fly Ash Provisions
	Comment:  Several commenters asked EPA to clarify the compliance dates for the CKD recycle rate provision for existing sources in §63.1344(h), the CKD recycle rate provision for new and reconstructed sources in §63.1344(i), and the provision on fly ash use in §63.1344(g).  The commenters recommend that EPA allow 1 year to comply with the fly ash provision for existing sources in §63.1344(g) and CKD recycle rate provision for existing sources in §63.1344(h).  That would make the compliance dates for these requirements consistent with the compliance date for existing sources to meet the THC good combustion practices (December 20, 2007) in §63.1351(c).
	One commenter asks that EPA revise the compliance date for the CKD recycle rate provision for new and reconstructed kilns in §63.1344(i).  Since EPA never proposed the provision, the final rule is more stringent than the proposal and sources commencing construction between December 2, 2005, and December 20, 2006, should be given 3 years to comply.
H.  Research and Technology
	Comment:  One commenter requests EPA to conduct further research on the concept of bypassing mercury-enriched dust from PM control devices or raw meal to clinker product.  ASTM and ASSHTO now allow intergrinding of 5 percent limestone with clinker to make Type I cement product.  Type II cement can have any greater amounts of other constituents.  There is the possibility that some dust or meal can be used to substitute milled clinker without harming the quality of the product.  Some plants may be able to use this approach to bleed mercury from the process.
	Comment:  One commenter, an ash management company, is investing in beneficiation technology with the goal of utilization of the fly ash as is done now in Europe.  This commenter asked EPA to assemble a technical record on the effects and uses of sorbents (and other approaches) to facilitate increased utilization.
	Comment:  One commenter identified SCR as an add-on control that can reduce THC and dioxins/furans (D/F) and convert mercury in the cement process into more collectible forms for subsequent bypass strategies.  Two other commercially available strategies rely on catalysts to reduce NOX, THC, or D/F.  One proven technology reacts ammonia with NOX in the presence of a catalyst with concurrent D/F and THC destruction.  The second uses catalytic material fibers that are woven and layered with standard baghouse fabric such that both the catalytic destruction of D/F and particulate control are achieved.  The fabric filter technology is described at www.environment.power.alstom.com/home/ by following the links to Industry Solutions/Products/Fabric Filters/Remedia Filter Bags.  EPA should review the role of SCR at some kilns as a THC and D/F control strategy in its reconsideration of the final rule.  SCR and catalytic fabric filters should be considered in EPA's multi-pollutant evaluation of the cement industry.
VI.  Summary of Cost, Environmental, Energy, and Economic

Impacts of Proposed Amendments

A.  What are the affected sources?

	There are currently 93 portland cement manufacturing facilities located in the U.S. and Puerto Rico that we expect to be affected by these proposed amendments.  In 2005, these facilities operated 152 cement kilns and associated clinker coolers.  We have no estimate of the number of raw material dryers that are separate from the kilns.
	Based on capacity expansion data provided by the Portland Cement Association, we anticipate that 20 new kilns and associated clinker coolers will be built in the five years after the promulgation of final standards representing 24 million tpy of clinker capacity.  Some of these new kilns will be built at existing facilities and some at new greenfield facilities.  The location of the kiln (greenfield or currently existing facility) has no bearing on our estimated cost and environmental impacts.  	We based new kiln impacts on a 1.2 million tpy clinker kiln.  This kiln is the smallest size anticipated for new kilns based on kilns built in the last five years or currently under construction.  Using the smallest anticipated kiln size provides a conservative estimate of costs because control costs per unit of capacity tend to be higher for smaller kilns.
B.  How are the impacts for this proposal evaluated?
	For these proposed Portland Cement NESHAP amendments, the EPA utilized three models to evaluate the impacts of the regulation on the industry and the economy.  Typically in a regulatory analysis, EPA determines the regulatory options suitable to meet statutory obligations under the CAA.  Based on the stringency of those options, EPA then determines the control technologies and monitoring requirements that may be selected to comply with the regulation. This is conducted in an Engineering Analysis.  The selected control technologies and monitoring requirements are then evaluated in a cost model to determine the total annualized control costs.  The annualized control costs serve as inputs to an Economic Impact Analysis model that evaluates the impacts of those costs on the industry and society as a whole.
      The Economic Impact Analysis model uses a single-period static partial-equilibrium model to compare a pre-policy cement market baseline with expected post-policy outcomes in cement markets. This model was used in previous EPA analyses of the portland cement industry (EPA, 1998; EPA, 1999b).  The benchmark time horizon for the analysis is assumed to be short and producers have some constraints on their flexibility to adjust factors of production. This time horizon allows us to capture important transitory impacts of the program on existing producers. The model uses traditional engineering costs analysis as "exogenous" inputs (i.e., determined outside of the economic model) and computes the associated economic impacts of the proposed regulation.
      For the Portland Cement NESHAP, EPA also employs the Industrial Sector Integrated Solutions (ISIS) model which conducts both the engineering cost analysis and the economic analysis in a single modeling system.  The ISIS model is a dynamic and integrated model that simulates potential decisions made in the cement industry to meet an environmental policy under a regulatory scenario.  ISIS simultaneously estimates 1) optimal industry operation to meet the demand and emission reduction requirements, 2) the suite of control technologies needed to meet the emission limit, 3) the engineering cost of controls, and 4) economic impacts of demand response of the policy, in an iterative loop until the system achieves the optimal solution.  More information on this model can be found in the ISIS Technical Support Document (TSD).  The peer review of the ISIS model will be available at http://www.epa.gov/ttn at a future date.
      In a Technical Memo to the docket, we provide a comparison of these models to provide an evaluation of how the differences between the models may impact the resulting estimates of the impacts of the regulation.  For example, the Engineering Analysis and Economic Impact Analysis evaluate a snapshot of implementation of the proposed rule in a given year (i.e., 2018, based on 2005 dollars) while ISIS evaluates impacts of compliance dynamically over time (i.e., 2013-2018).  In general, given the optimization nature of ISIS, ISIS accounts for more flexibility when estimating the impacts of the regulation. For example, when optimizing to meet an emission limit, ISIS allows for the addition of new kilns, as well as kiln retirements, replacements, and expansions and the installation of controls.  In the Engineering Analysis the existing kiln population is assumed to be constant even though normal kiln retirements occur. Overall, we anticipate the total control costs from the Engineering Analysis to be higher than that of ISIS.  With higher cost estimates serving as the basis for the Economic Impact Analysis along with other modeling differences, we expect the results presented from the EIA model will be higher in impact than those presented by ISIS.
      In addition, we have not yet developed ISIS modules to calculate non-air environmental impacts and energy impacts.  Therefore, these sections only contain impacts calculated by the traditional engineering methods
C.   What are the air quality impacts?

For the proposed Portland Cement NESHAP, EPA estimated the emission reductions	that would occur due to the implementation of the proposed emission limits.  EPA estimated emission reductions based on the control technologies selected by the engineering analysis.  These emission reductions are based on 2005 emission baselines.
Under the proposed limit for mercury, we have estimated that the emissions reductions would be 13,400 lb/yr for existing kilns. Based on our 1.2 million tpy model kiln, mercury emissions would be reduced by 149 lb/yr for each new kiln, or about 3,000 lb/yr 5 years after promulgation of the final standards.
Under the proposed limits for THC, we have estimated that the emissions reductions would be 14,000 tpy for existing kilns, which represent an organic HAP reduction of 3,360 tpy.  For new kilns, THC emissions would be reduced by 39 tpy per kiln or about 800 tpy 5 years after promulgation of the final standard.  This represents an organic HAP reduction of 192 tpy.
Under the proposed limit for HCl, we have estimated that emissions would be reduced by 3,000 tpy for existing kilns. Emissions of HCl from new kilns would be 45 tpy per kiln or 900 tpy 5 years after promulgation of the final standards.
The proposed emission limits for PM represent a lowering of the PM limit from 0.5 lb/ton of clinker to 0.085 lb/ton of clinker for existing kilns and for new kilns, a lowering to 0.080 lb/ton of clinker. We have estimated that PM emissions would be reduced by 10,300 tpy for existing kilns. For new kilns, emission reductions would be 160 tpy per kiln, or about 3,200 tpy 5 years after promulgation of the final standards.
The proposed standards for mercury, THC and HCl will also result in concurrent control of SO2 emissions. For kilns that use an RTO to comply with the THC emissions limit it is necessary to install an alkaline scrubber upstream of the RTO to control acid gas and to provide additional control of PM and to avoid plugging and fouling of the RTO. Scrubbers will also be used to control HCl and mercury emissions. Reductions in SO2 emissions associated with controls for mercury, THC and HCl are estimated at 1,600 tpy, 11,700 tpy, and 106,000 tpy, respectively. Total reduction in SO2 emissions from existing kilns would be an estimated 119,300 tpy. A new 1.2 million tpy kiln equipped with a scrubber will reduce SO2 emissions by 1,000 tpy on average or about 20,000 tpy in the fifth year after promulgation of the final standards.
These controls will also reduce emissions of secondary PM2.5 (and coarse PM  -  PM10-2.5 as well).  This is PM that results from atmospheric transformation processes of precursor gases, including SO2.
In addition to this traditional estimation of emission reductions, EPA employed the ISIS model to estimate emission reductions.  The estimation of emission reductions in the ISIS model accounts for the optimization of the industry and includes the addition of new kilns, kiln retirements, replacements, and expansions as well as installation of controls.  Using the ISIS model, in 2013 we estimate reductions of 12,000 lbs of mercury, 11,951 tons of THC, 2,791 tons of HCl, 10,554 tons of PM and 163,309 tons of SO2 compared to total emissions in 2005.  More information on the ISIS model and results can be found in the ISIS TSD and in a Technical Memo to the docket.
D.	What are the water quality impacts?

We estimated no water quality impacts for the proposed amendments.  The requirements that might result in the use of alkaline scrubbers will produce a scrubber slurry liquid waste stream.  However, we assume the scrubber slurry produced will be dewatered and added back into the cement-making process as gypsum.  Water from the dewatering process will be recycled back to the scrubber.  The four facilities that currently use wet scrubbers in this industry report no water releases at any time.  However, if the use of scrubbers becomes more widespread there could be a potential for a water release due to system purges.  We are requesting comment on what, if any, regulations might apply, and if we should add any requirements to this rule to prevent or control these purges.  The addition of scrubbers will increase water usage by about 2,789 million gallons per year. For a new 1.2 million tpy kiln, water usage will be 36 million gallons per year or 720 million gallons per year 5 years after promulgation of the final standards.
We note that some preproposal commenters have stated that some new and existing facilities may be located in areas where there is not sufficient water to operate a wet scrubber.  However, we are not mandating the use of wet scrubber technology in these regulations, and we believe that sufficient alternative controls exist for mercury and acid gas controls that this issue would not preclude a facility from meeting these proposed emissions limits.  However, we are also soliciting comment on this issue.
E.	What are the solid waste impacts?

The potential for solid waste impacts are associated with greater PM control for kilns, waste generated by ACI systems and solids resulting from solids in scrubber slurry water.  As explained above, little or no solid waste is expected from the generation of scrubber slurry.  The PM captured in the kiln fabric filter (cement kiln dust) is essentially recaptured raw material, intermediate materials, or product.  Captured PM is typically recycled back to the kilns to the maximum extent possible.  We estimate that any additional PM captured would also be recycled to the kiln because facilities minimize CKD disposed of as solid waste to the minimum required to maintain product quality.  Increasing the amount of PM capture should not affect the minimum amount of PM required to be wasted.
Where equipped with an alkali bypass, the bypass will have a separate PM control device and that PM is typically disposed of as solid waste.  An alkali bypass is not required on all kilns.  Where one is present, the amount of solid waste generated from the alkali bypass is minimal, usually about 1 percent of total CKD in control devices, because the bypass gas stream is a small percentage of total kiln exhaust gas flow and the bypass gas stream does not contact the feed stream in the raw mill.
Waste collected in the polishing baghouse associated with ACI that might be added for mercury or THC control cannot be recycled to the kiln and would be disposed of as solid waste.  An estimated 120,400 tpy of solid waste would be generated from the use of ACI systems on existing kilns.  Each new kiln equipped with an ACI system would be expected to generate 1,800 tons of solid waste per kiln or, assuming 14 of the 20 new kilns would add ACI systems, about 25,000 tpy in the fifth year after promulgation of the final standards.
In addition to the solid waste impacts described above, these is a potential for an increase in solid waste if a facility elects to control mercury emission by increasing the amount of CKD wasted rather than returned to process.  This will be a site-specific decision, and we have no data to estimate the potential solid waste that may be generated by this practice.  However, we expect the total amount to be small for two reasons.  First, wasting cement kiln dust for mercury control represents a significant expense to a facility because they are essentially wasting either raw materials or product.  So we anticipate this option will not be used if the amount of CKD wasted would be large.  Second, we believe that cement manufacturers will add the additional CKD to the finish mill to the maximum extent possible rather then waste the material.

F.	What are the secondary impacts?

Indirect or secondary air quality impacts include impacts that would result from the increased electricity usage associated with the operation of control devices as well as water quality and solid waste impacts (which were just discussed) that would occur as a result of these proposed revisions. We estimate these proposed revisions would increase emissions of criteria pollutants from utility boilers that supply electricity to the portland cement facilities. We estimate increased energy demand associated with the installation of scrubbers, ACI systems, and RTO. The increases for existing kilns are estimated to be 1,700 tpy of NOx, 800 tpy of CO, 3,000 tpy of SO2 and about 80 tpy of PM. For new kilns (assuming that of the 20 new kilns to start up in the 5 years following promulgation of the final standard 20 will add alkaline scrubbers, 2 will add an RTO, 14 will install ACI systems, and 20 will install membrane bags instead of cloth bags in their baghouses), increases in secondary air pollutants are estimated to be 400 tpy of NOx, 200 tpy of CO, 700 tpy of SO2 and 20 tpy of PM.  We also estimated increases of greenhouse gas emissions (chiefly CO2) to be 800,000 tpy (existing kilns) and 200,000 tpy (new kilns).
G.	What are the energy impacts?

The addition of alkaline scrubbers, ACI systems, and RTO added to comply with the proposed amendments will result in increased energy use due to the electrical requirements for the scrubber and ACI systems and increased fan pressure drops, and natural gas to fuel the RTO. We estimate the additional national electrical demand to be 730 million kWhr per year and the natural gas use to be 700,000 MMBtu per year for existing kilns. For new kilns, assuming of the 20 new kilns to start up in the 5 years following promulgation of the final standard that 20 will add alkaline scrubbers, 2 will add an RTO, and 14 will install ACI systems, the electrical demand is estimated to be 180 million kWhr per year and the natural gas use to be 175,000 MMBtu per year.
H.	What are the cost impacts?

Under the proposed amendments, existing kilns are expected to add one or more control devices to comply with the proposed emission limits. In addition, each kiln would be required to install CEMS to monitor mercury, THC and HCl while bag leak detector (BLD) would be required to monitor performance of all baghouses.
We performed two separate cost analyses for this proposed rule.  In the engineering cost analysis we estimated the cost of the proposed amendments based on the type of control device that was assumed to be necessary to comply with the proposed emission standards. Based on baseline emissions of mercury, THC, HCl and PM for each kiln and the removal efficiency necessary to comply with the proposed emission limit for each HAP, an appropriate control device was identified. In assigning control devices to each kiln where more than one control device would be capable of reducing emissions of a particular HAP below the limit, we assumed that the least costly control would be installed.  For example, if a kiln could use either a scrubber or ACI to comply with the proposed limit for mercury, it was assumed that ACI would be selected over a scrubber because an ACI system would be less costly.  ACI also is expected to achieve a higher removal efficiency than a scrubber for mercury. In some instances, a more expensive technology was considered appropriate because the selected control reduced emissions of multiple pollutants.  For example, even though ACI would be less costly than a scrubber for controlling mercury, if the kiln also had to reduce HCl emissions, we assumed that a scrubber would be applied to control HCl as well as mercury because ACI would not control HCl.  However, for many kilns, our analysis assumes that multiple controls will have to be added because more than one control will be needed to control all HAP.  For example, ACI may be considered necessary to meet the limits for THC and/or mercury.  For the same kiln, a scrubber would also be required to reduce HCl emissions.  In this case we would allocate the cost of the control to controlling HCl emissions, not to the cost of controlling mercury emissions.  In addition, once we assigned a particular control device in most cases we assumed mercury and THC emissions reductions would equal the control device efficiency, and not the minimum reduction necessary to meet the emissions limit.  We believe this assumption is warranted because it matches costs with actual emissions reductions.  In the case of PM and HCl, we assumed the controlled facility would emit at the average level necessary to meet the standard (i.e., we assumed for PM that the controlled facility would emit at 0.01 lb/ton clinker, the average emission level, not 0.085 lb/ton clinker, the actual emissions limit), because the proposed emissions levels are extremely low.
In a separate analysis performed using the ISIS model, we input into ISIS the baseline and controlled emissions rates for each pollutant, along with the maximum percent reduction achievable for a particular control technology, and allowed ISIS to base the control required on optimizing total production costs.  In addition, the ISIS model accounts for normal kiln retirements that would occur even in the absence of any regulatory action (i.e., as new kiln come on-line, older less efficient and more costly to operate kilns are retired).  In the first cost analysis, total national annual costs assume that all kilns currently operating continue to operate while 20 new kilns come on-line.
Table 8 presents the resulting add-on controls each approach estimated was necessary to meet the proposed emissions limits.
Table 8.  Control Installation Comparison

LSW
ACI
LWS+ACI
RTO
MB
FF
WS+RTO
Engineering Analysis
5
36
111
0
10
5
12
ISIS Model
4
26
93
14
0
0
0

  In the engineering analysis we estimated the total capital cost of installing alkaline scrubbers and ACI systems for mercury control, including monitoring systems, would be $71 million with annualized cost of $27 million. The estimated capital cost of installing ACI systems and RTO/scrubbers to reduce THC emissions would be $355 million with annualized cost of $110 million. The capital cost of adding scrubbers for the control of HCl is estimated to be $766 million with annualized cost of $124 million. The capital cost of adding membrane bags to existing baghouse and the replacement of ESP's with baghouses would be $56 million with annualized cost of $17 million. The total capital cost for the proposed amendments would be an estimated $1.23 billion with an annualized cost of $275 million.
The estimated emission control capital cost per new 1.2 million tpy kiln is $16.6 million and the annualized costs are estimated at $1.25 million for mercury control, $1.0 million for THC control, $1.8 million for HCl control and $270,000 for PM control. National annualized cost by the end of the fifth year will be an estimated $86.4 million.
In the ISIS results, we are not able to separate costs by pollutant because the model does an overall optimization of the production and air pollution control costs. The total annual costs of the ISIS model are $167 million in 2013, and are anticipated to increase to $180 million in 2018.  These impacts assume that in 2013 7 new kilns are installed and net 10 kilns are retired. These retirements include two kilns that we have determined may close due to not being able to meet the mercury emission limits due to unusually high mercury contents in their proprietary quarries (i.e., the mercury content of the raw material at limestone quarries).
I.  What are the economic impacts?
	EPA employed both a partial-equilibrium economic model and the ISIS model to analyze the impact on the industry and the economy.
	The Economic Impact Analysis model estimates the average national price for portland cement could be 4 percent higher with the NESHAP, or $3.30 per metric ton, while annual domestic production may fall by 8 percent, or 7 million tons per year. Because of higher domestic prices, imports are expected to rise by 2 million metric tons per year.
	 As domestic production falls, cement industry revenues are projected to decline by 4 percent, or $340 million. Overall, net production costs also fall by $140 million with compliance cost increases ($240 million) offset by cost reductions associated with lower cement production. Operating profits fall by $200 million, or 16 percent. Other projected impacts include reduced demand for labor. Employment falls by approximately 8 percent, or 1,200 employees. EPA identified six domestic plants with negative operating profits and significant utilization changes that could temporarily idle until market demand conditions improve. The plants are small capacity plants with unit compliance costs close to $5 per ton and $50 million total change in operating profits. Since these plants account for approximately 2.5 percent of domestic capacity, a decision to permanently shut down these plants would reduce domestic supply and lead to additional projected market price increases.
	The estimated domestic social cost of the proposed amendments is $684 million. There is an estimated $89 million surplus gain for other countries producing cement.  The social cost estimates are significantly higher than the engineering analysis estimates, which estimated annualized costs of $370 million. This is a direct consequence of EPA's assumptions about existing domestic plants' pricing behavior.  Under baseline conditions without regulation, the existing domestic cement plants are assumed to choose a production level that is less than the level produced under perfect competition. The imposition of additional regulatory costs tends to widen the gap between price and marginal cost in these markets and contributes to additional social costs. For more detail see the Regulatory Impact Analysis (RIA).
	Using the ISIS model, we estimate cement demand to drop 2.9 percent in 2013 or 3.9 million tons with an average annual drop in demand at 2.3 percent or 3.2 million tons per year during the  2013-2018 time period.  The drop in demand will affect the level of imports, and imports are likely to rise slightly over the policy horizon.  In 2013, imports rise 2.6 percent or 0.92 million tons with an annual average of 2.3 percent or 0.89 million tons per year throughout the 2013-2018.  ISIS estimates the average national price for portland cement in the 2013-2018 time period to be 0.2 percent higher with the NESHAP, or $0.20 per metric ton.  However, some markets could see an increase by up to 4.5 percent.  Total annualized control cost for the proposed NESHAP amendments is projected to be $167 million in 2013, and is expected to increase to $180 million in 2018, as additional new units come online to meet the projected increase in demand.
	With respect to the baseline case in 2013, ISIS identified a net retirement of 5.2 million tons of capacity.  The retirements affect 10 kilns at 8 facilities.  As a result of the proposed NESHAP amendments, the cost to produce a ton of cement (production, imports, transportation and control technology) increases from $56.11 per ton at baseline to $57.83 per ton as a result of these proposed amendments ($1.72/ton), resulting in an increase of about 3 percent over the analysis period of 2013 to 2018.  With respect to baseline in 2013 ISIS projects the revenue of the cement industry to fall by 8 percent or about $615 million.  More information on this model can be found in the ISIS TSD and in a Technical Memo to the docket.
J.  What are the benefits?
We estimate the monetized benefits of this proposed NESHAP to be $4.4 billion to $11 billion (2005$, 3percent discount rate) in the year of full implementation (2013); using alternate relationships between PM2.5 and premature mortality supplied by experts, higher and lower benefits estimates are plausible, but most of the expert-based estimates fall between the two estimates we present above.  The benefits at a 7 percent discount rate are $4.0 billion to $9.7 billion (2005$).  We base the estimate of human health benefits derived from the PM2.5 and PM2.5 precursor emission reductions on the approach and methodology laid out in the TSD that accompanied the RIA for the revision to the National Ambient Air Quality Standard for Ground-level Ozone (NAAQS), March 2008 with several updates explained below.  We generated estimates that represent the total monetized human health benefits (the sum of premature mortality and morbidity) of reducing PM2.5 and PM2.5 precursor emissions.  A summary of the monetized benefits estimates at discount rates of 3 percent and 7 percent is in Table 7 of this preamble.

Table 7.  Summary of the Monetized Benefits Estimates for the Proposed Portland Cement NESHAP
                                   Pollutant
                          Emission reductions (tons)
      Total monetized benefits (millions of 2005 dollars, 3% Discount)[1]
  Total monetized benefits (millions of 2005 dollars, 7 percent Discount)[1]
                                 Direct PM2.5
                                     6,300
                               $1,200 to $2,800
                               $1,000 to $2,500
                               PM2.5 precursors
                                    140,000
                               $3,300 to $8,000
                               $3,000 to $7,200
                                 Grand total:
                               $4,400 to $11,000
                               $4,000 to $9,700
[1]All estimates are for the analysis year (full implementation, 2013), and are rounded to two significant figures so numbers may not sum across rows.  PM2.5 precursors reflect emission reductions of SOx.  All fine particles are assumed to have equivalent health effects, and the monetized benefits incorporate the conversion from precursor emissions to ambient fine particles.  These monetized benefits do not include HAP reductions, additional emission reductions that would occur if cement facilities temporarily idle or reduce capacity utilization as a result of this regulation, or the unquantifiable amount of reductions in condensable PM.
The specific estimates of benefits per ton of pollutant reductions included in this analysis are