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National Emission Standards for Hazardous AirPollutants (NESHAP) FORLimeManufacturingBackground Information Document
- Vol II

PUBLIC COMMENTS AND RESPONSES


## ( August 2003

Emission Standards Division



# u.s. Environmental ProtectionAgency Office ofAir Quality Planning and Standards Research Triangle Park, North Carolina27711

### ( Section TABLE OF CONTENTS Page



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( 1.0 Summary 1-1 1.1 Table 1-1 ListofCommenters 1-2
2.0 Rule Changes Since Proposal 2-1 2.1 EmissionLimits 2-1 2.2 Monitoring Requirements 2-1 2.3 EmissionTesting and Reports 2-2 2.4 Applicability 2-2 2.5 Averaging Periods for Monitoring 2-2 2.6 Averaging Kiln Emissions 2-3
3.0 Comment Summaries and EPA Responses 3-1 3.1 Subcategoryfor Scrubber-EquipmentKilns 3-1 3.2 PM Emission Limit for Scrubber-EquipmentKilns 3-17 3.3 PM Emission LimitforNew Kilns 3-18 3.4 PM Emission Limit

- General 3-19 3.5 Monitoring Requirements for Scrubber-Equipped Kilns 3-22 3.6 Monitoring Requirements for Kilns 

### wi Dry Pollution Control Devices 3-23 3.7 Operating Parameters 3-27 3.8 OpacityLimit 3-29 3.9 Stone Handling Operations 3-31 3.10 TestMethods 3-32 3.11 Economic ImpactAnalysis 3-36 3.12 RiskAnalysis 3-42 3.13 Applicability 3-43 3.14 General Comments 3-44

## ( 1.0 SUMMARY On December 20,2002, the U.S. Environmental Protection Agency (EPA) proposed national emission standards for hazardous air pollutant (HAP) emissions from lime manufacturing plants located at major source facilities (67 FR 78046). These proposed standards implemented section 112(d) ofthe Clean AirAct as amended in 1990 (CM). There were 24 comment letters on the proposal (see Table 1-1), and the commenters consisted oftrade associations, manufacturers, and engineering firms, and the general public. Summaries ofthe comments, and the EPA's responses, are presented in this background information document (BID Volume II). This summary of comments and responses served as the basis for the revisions made to the rule between proposal and promulgation. Besides summarizing the comments and responses, this document also presents a summary ofthe rule revisions. This document supplements the information used to develop the proposed rule, which is the docket for this rulemaking.

1-1(



### ( Table 1-1 List ofCommenters (SeeDocketNo. OAR-2002-0052 and DocketA-95-41-NationalEmission Standards for Hazardous Air Pollutants forLimeManufacturingPlants for the comments)

Document Date Rcvd Cementer, Addressee, Title or Date of

Number in Docket Description, etc. Document IV-D-01 02-13-03 John S. Morawetz, Center Director, 02-14-03 ICWUC Centerfor Worker Health and Safety Education, Cincinnati, OH. IV-D-02 02-18-03 A. J. Paris, President, Huron Lime Inc. 02-14-03 IV-D-03 02-18-03 William M. Brant, Director, Miami-Dade 02-18-03 Water and Sewer Department, Miami, FL. IV-D-04 02-18-03 Arline M. Seeger, Executive Director, 02-18-03 National Lime Association, Arlington, VA. IV-D-05 02-18-03 Tony C. Panchyshyn, Senior 02-14-03 Environmental Engineer, Graymont Western US Inc., Salt Lake City, UT. IV-D-06 02-18-03 J. Oscar Robinson, General Partner, 02-16-03 Austin White Lime Co., Austin, TX. IV-D-07 02-18-03 Dana Stone, Vice President, Operations, 02-13-03 Cutler-Magner Company, Duluth, MN. IV-D-08 02-18-03 Harold W. Robbins, President, Bison 02-14-03 Engineering Inc., Helena, MT. IV-D-09 02-18-03 James R. Carson, Senior Staff Engineer, 02-17-03 Environmental Affairs, Ispat Inland Inc., East Chicago, IN. IV-D-10 02-18-03 Jeffrey P. LaCosse, President and 02-17-03 Principal Scientist, Spectral Insights LLC, Durham, NC. IV-D-11 02-18-03 Steve Raffensperger, Vice President- 02-17-03 General Manager, MidAmerica Division, Martin Marietta Aggregates, Mason, OH. IV-D-12 02-18-03 Lucie Macalister, Environmental Engineer, 02-14-03



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( Table 1-1 List ofCommenters (See Docket No. OAR-2002-0052 and DocketA-95-41-National Emission Standards for Hazardous AirPollutants for Lime Manufacturing Plants for the comments)

Document Date Rcvd Cementer, Addressee, Title or Date of

Number in Docket Description, etc. Document Linwood Mining and Minerals Corp., Davenport, IA. IV-D-13 02-18-03 Robert J. Bartosh, SeniorVice President 

### & 02-13-03 COO, Dakota Coal Company, Bismarck, ND. IV-D-14 02-18-03 Louis Wolfe, Private Citizen, Newark, DE. 02-15-03 IV-D-15 02-18-03 Stephen A. Loeschner, Private Citizen, 02-18-03 Fort Wayne, IN. IV-D-16 02-18-03 Ron Downey, Director, Environmental 02-18-03 Compliance, LWB Refractories, York, PA. IV-D-17 02-18-03 Darin Klewsaat, Assistant Operations 02-21-03 Director, Southern Lime Company, Calera, AL. IV-D-18 02-11-03 Lecia Craft, Vice President of Environment, 02-11-03 Pete Lien 

### &Sons Inc., Rapid City, SD. IV-D-19 02-10-03 Craig Clapsaddle, Mechanical Systems 02-10-03 Inc. (MSI), Raleigh, NC. IV-D-20 02-17-03 Fred Nast, Chief Executive Officer, 02-17-03 Western Lime, West Bend, WI. IV-D-21 02-18-03 Spencer C. Stinson, General Manager, 02-18-03 Global Stone Chemstone Corp., Strasburg, VA. IV-D-22 02-17-03 Johnney G. Bowers, Vice President, 02-12-03 Manufacturing, United States Lime 

### & Minerals Inc., Dallas, TX. IV-D-23 02-15-03 Comment entitled II**~~N** AIR IS 02-15-03 ESSENTIAL." subml e By JeanPublic@yahoo.com.


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### Table 1-1 ListofCommenters (See DocketNo. OAR-2002-0052 and DocketA-95-41 -NationalEmission Standards for Hazardous AirPollutants forLimeManufacturingPlants for the comments)

Document Date Rcvd Cementer, Addressee, Title or Date of

Number in Docket Description, etc. Document IV-G-01 02-24-03 

### J. Steven Castleberry, Environmental 02-18-03 Affairs Manager, Mississippi Lime, Alton, 

### IL. (This document contains Confidential Business Information. Please contact the project officer ifyou need to review.)



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## ( 2.0 Rule Changes Since Proposal


### 2.1 Emission Limits
We proposed aparticulatematter (PM) standard (as a surrogate for non-mercury hazardous airpollutant [HAP] metals) of0.12 pounds PMperton stone feed (lb/tsf) reflecting theperformance ofdrypollutioncontrol systems (baghouses). We also solicited comment on having a separate PM standard of0.60 lb/tsfforkilns controlledwith wet scrubbers. Inthe final rule, we have decided to adoptthese two different standards for PM emissions from existing lime kilns. We are also indicating thatexisting kilns subjectto the 0.60 IbltsfPMemissionlimit are notto be included in any averaging scheme for demonstrating compliance with a PM standard.


### 2.2 Monitoring Requirements In the proposed NESHAP, we required facilities using wet scrubbers to monitor scrubber pressure drop and liquid flow rate. We have written the final NESHAP to explicitly state that alternative monitoring procedures are allowed underthe procedures described in 40 CFR 63.8(f). However, we do not delegate that authority. The proposed NESHAP stated that you must install, operate, and maintain a continuous opacity monitoring system (COMS) as required by 40 CFR part 63, subpart A, General Provisions, and according to PS-1 in Appendix B to 40 CFR part 60. We have stated in the rule that COMS installed, relocated, or substantially refurbished after February 6, 2001, must meet the requirements of PS-1 as revised on August 10, 2000. Any COMS installed on or before February 6,2001, should continue to meetthe requirements in effect at the time of installation unless specifically required by the local regulatory agency to re-certify the COMS in question. In the proposed NESHAP, we required you to monitorthe performance offabric filters (FF) with either a COMS or a PM detector. In the final NESHAP, we are allowing existing facilities to monitor FF performance using daily EPA Method 9, in Appendix A to 40 CFR part 60, visible emission readings ifthe facility has a positive pressure FF with multiple stacks, or if it is infeasible to install a COMS in accordance with PS-1 in Appendix B to 40 CFR part 60.
In the proposed NESHAP, we allowed three alternatives for monitoring electrostatic precipitator (ESP) performance. These were a COMS, a PM detector, or monitoring ESP voltage and current. In the final NESHAP, we are allowing only two alternatives, a COMS or a PM detector. There are no requirements to establish ESP voltage and current operating limits. In the proposed NESHAP, we specified that EPA Method 9 in AppendixA to 40 CFR part 60 should be used to determine opacity from fugitive emissions. We have retained this requirement in the final NESHAP, but we have added additional



### 2-1

## ( requirements on how EPA method 9 in Appendix A to 40 CFR part 60 should be implemented to determine fugitive visible emissions. This language was taken directly from 40 CFR 60.675(c)(1).

In the proposed NESHAP, §63.7120(b) could be interpreted to imply that processed stone handling (PSH) operations must be continuously monitored. In the final NESHAP, PSH operations are subject to monthly (not continuous) visible emission testing. 

### 2.3 Emission Testing and Reports
In the proposed NESHAP, we required that lime kiln emission testing be conducted at the highest production level reasonably expected to occur. In the final NESHAP, we require that lime kilns be tested under representative operating conditions.
In the proposed NESHAP, we required reporting of deviations from operating, visible emissions, and opacity limits, including those deviations that occur during periods of startup, shutdown, or malfunction. In the final NESHAP, we require that ( reports are to be made in accordance with 40 CFR 63.1 O(d).
In the proposed NESHAP, we required testing of all kilns in order to claim area source status. In the final NESHAP, we have included a provision that allows the permitting authority to determine if idled kilns must be tested, and also to determine whether all kilns that use identical feed materials, fuels, and emission controls must still all be tested. 

### 2.4 Applicability
In the proposed NESHAP, the raw material storage bin was the first emission unit in the sequence of lime manufacturing that was part ofthe affected source. Materials rocessin <> erations between the stora e bin and the kiln were also covered. storage bins are defined as manmade enclosures, and use the term processed stone handling operations instead of materials processing operations.
In the proposed NESHAP, we included as an affected source lime kilns that produced lime product from any calcareous substance. In the final NESHAP, we have excluded lime kilns that produce lime from water softening sludge that contain calcium carbonate. 

### ( 2-2In the proposed NESHAP, we excluded materials handling operations associated with lime product. In the final NESHAP, we have specifically stated that nuisance dust collectors are part of lime product handling systems and, therefore, are not part ofthe affected source. In the proposed NESHAP, we defined the affected source as the collection of all ofthe lime kilns, lime coolers and materials processing operations. We noted that this language could be misinterpreted to imply that a new lime kiln erected at an existing lime manufacturing plant would be considered existing, not new. In the final NESHAP, we have written the language in 40 CFR
63.7082 to make our intent clear. New lime kilns, whether or not they are built at an existing lime manufacturing plant, must meet the PM emission limits for new sources. 

### 2.5 Averaging Periods for Monitoring
In the proposed NESHAP, we required that facilities use rolling 3-hour averages to show compliance with wet scrubber operating limits. We noted that in the proposed rule, we did not clearly state how to calculate the rolling average. Based on compliance requirements of other NESHAP, we determined that a rolling average was not necessary to ensure compliance, but did increase the complexity ofthe average ( calculation and record keeping process. Therefore, in the final NESHAP, we require block 3-hour averages instead of rolling 3-hour averages, which is consistent with the requirement to use block averaging required for ESP that choose to monitor using COMS. 

### 2.6 Averaging Kiln Emissions
In the proposed NESHAP, we allowed averaging among all lime kilns and coolers at existing sources, and all new lime kilns and coolers at new sources, but did not allow averaging of existing and new lime kilns and coolers together. In addition, the averaging provisions and equations applied whether or not the facility desired to average. We have written the final NESHAP to state that each individual new lime kiln and its associated cooler must meet a 0.10 

### Ib/tsfPM emission limit, and each individual existing lime kilns and its associated cooler must meet a 0.12 

### Ib/tsfPM emission limit. Averaging is optional, so that if each individual kiln meets its emission limit, averaging is not required. The exception to this is for existing kilns which are subject to the 0.60 

### Ib/tsfPM emission limit. These kilns are not eligible for averaging. Ifthe lime manufacturing plant has multiple kilns and wants to average kilns together to meet the PM emission limit, this is allowed (with one limitation discussed below, and the exception for kilns subject to the 0.60 

### Ib/tsfPM emission limit noted above) and the averaging equations in the final rule must be used. However, in no



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( case maya new kiln exceed a 0.10 

### Ib/tsfemission limit. Where there are both new and existing lime kilns at a facility, then the PM emission limit will be an average ofthe existing and new kiln PM emissions limits, weighted by the annual actual production rates ofthe individual kilns. We believe that allowing averaging is appropriate here because ofthe identity ofthe units (kilns and coolers in all cases), and the emissions (same HAP in same type of emissions, since all emissions result from kilns and coolers). Averaged emissions underthese circumstances would, thus, still reflect MACT for the affected source. The averaging provisions are included in the final NESHAP as a result ofthe recommendations ofthe Small Business Advocacy Panel convened as required by section 609(b) ofthe Regulatory FlexibilityAct (RFA) and improves the compliance flexibility options for small businesses, which is the intent of the RFA. The only limitations we are requiring on averaging are: 1) any new kiln, when considered alone, must meet the 0.10 

### Ib/tsfemission limit; 2) kilns equipped with wet scrubbers for PM emissions control are not eligible for averaging; 3) we are not allowing averaging for other emission sources, orfor opacity.



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### ( 3.0 Comment Summaries and EPA Responses
3.1 Subcategory for Scrubber-Equipped Kilns
Comment
Inthe preamble to the proposed rule, EPArequested comment on establishing a subcategory for existing kilns equipped with wet scrubbers, ifitcould be demonstrated factually thatthere wouldbe significantenvironmentally counterproductive effects due to increased emissions ofacid gases, increased energyuse, or increased wateruse. (See 67 FR at 78058.) Several commenters (IV-D-04, IV-D-06, IV-D-02, IV-D-16, and IV-D-22) asked that a subcategory for scrubber-equipped kilns be established. One commenter (IV-D-04) also asked thatkilns vented through a mine chamberbe defined as scrubber-equippedkilns. The basis for this request, in the commenters' view, is that wet scrubbers cannotmeetthe proposedparticulate matter (PM) standard of0.12 pounds ofPM perton solid feed (lb/tsf), and therefore kilns with scrubbers wouldhave to replace them withbaghouses. (They also assertthat in most cases, wet scrubbers have higher annualized costs comparedto baghouses. Therefore, even ifa wet scrubbercould meet a 0.12 lbltsfemissionlevel, facilities will optto use baghouses due to cost considerations. See comments on costs which follow.) This will result in an increase in emissions ofHCI [ahazardous airpollutant (HAP)] and S02 (anon-HAP criteriapollutant), for a nominal decrease in HAP metal emissions. ( In support ofthis request one commenterprovided estimates thatnot establishing the requested wet scrubber subcategory would result in a metal HAP emissions decrease of3 tons peryear (tpy), butwouldresult in an increased emissions of1823 tpy for HCI and 2894 tpy for S02.
One commenter (IV-D-12) statedthat 

### ithadpreviouslyprovided information onthe effect ofreplacing wet scrubbers withbaghouses. They claimed thatreplacing one plant's wetPM control systemwith abaghouse will increase HCI by over20 tpy, but only decrease metal HAP by481 pounds peryear (DocketItemNo. I-B-116, Appendix C).
Anothercommenter (lV-D-02) estimatedthatHAP currentlybeing discharged from its three existing kilns are 29 tpy ofHCI and 0.38 tpy ofHAP metals. The emissions from the same kilns ifdry airpollution control equipmentwere used would be 652 tpy ofHCI and 0.075 tpyof HAP metals. They also claimthatthe higheroperating temperatures ofdry systems cause metals to vaporize and pass through aparticulate collector, resulting in a lowermetal concentration in the capturedparticulate. As aresult, they claimthat eventhough dry control equipmentmay reduce HAP metals emissions, the reduction will be minimal, while the release ofHCI will increase significantly. In addition, the commenternotes that approximately 39 percentofthe HAP metal emissions attributedto the lime industry is manganese, which is notclassified as a known or suspected carcinogen. The commenterprovides datawhich it claims showthe only conventional pollutantthat will be reduced with the installation ofa dry control system will be particulate emissions, and, "fugitive dust emissions from a dry system could more than offsetthe improvedparticulate collection on the kiln exhausts."

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## ( Response Standards implementing section 112 (d) ofthe Act must, of course, be of a minimum level ofstringency, usually referred to as the MACT floor. For existing sources, this floor level of control cannot be less stringent than "the average emission limitation achieved by the best performing 12 percent ofthe existing sources (forwhich the Administrator has emissions information)." In this rule, EPA is establishing section 112 (d) standards to control emissions of HAP metals, for which PM is a surrogate. None ofthe commenters challenge that the level of PM emissions reflecting the average ofthe 12 per cent ofthe best performing sources is 0.12 

### Ib/tsf. Notwithstanding, the commenters contend that EPA should subcategorize on the basis ofthe type of air pollution control device used, and then separately determine the floor for each subcategory. Although the Act contemplates that EPA may establish subcategories when promulgating MACT standards, subcategorization typically reflects "differences in manufacturing process, emission characteristics, ortechnical feasibility". See 67 FR at 78058; see also 63 FR at 18768 (April 15, 1998) determining whether or not to subcategorize based on "the type of equipment used in the process, the emission potential of each emission point, and any variations in the process due to pulp type". A classic example, provided in the legislative history to section 112 (d), is of a different process leading to different emissions and different types of control strategies

- the specific example being Soderberg and prebaked anode primary aluminum processes.
lSection 112 (d) (1) provides that "[t]he Administrator may distinguish among classes, types, and sizes of sources within a category or subcategory in establishing such standards

.....". In addition, section 112 (c) (1) encourages EPA to adhere to the subcategorization scheme already used in establishing NSPS: "To the extent practicable, the categories and subcategories listed underthis subsection shall be consistent with the list of source categories established pursuant to section 111 [requiring EPA to establish technology-based New Source Performance Standards] and Part 

## e" (although the NSPS for the lime industry does not contain subcategories, nor was it ever suggested when establishing NSPS that subcategories would be appropriate).



### 3-2( [See A Legislative History ofthe Clean AirAct Amendments of 1990 at 1138-39 (floor debates on Conference Report)]. Normally, it would be legally impermissible to subcategorize based on the type of air pollution control device. The problem with subcategorizing on the basis of pollution control device, quite simply, is that it leads to situations where floors are established based on something other than the "best performing" sources. For example, suppose a source category consists of 100 sources using the same process and having the same emission characteristics, but that 50 sources use control device A to control HAP emissions, and 50 use control device B which is two orders of magnitude less efficient. If one subcategorized based on the type of pollution control device, the MACT floor for the 50 sources with control device B would reflect worst, ratherthan "best" performance. Although the disparity in levels of emission control between the best performing sources here, and the best performing sources using wet scrubbers is not this dramatic

- roughly a factor of 5, not orders of magnitude

- the difference is nonetheless ample and evident.



## (

(
, The question ofwhether it is permissible to subcategorize on the basis of pollution control device has been litigated in the context ofthe effluent guideline provisions ofthe Clean WaterAct. These provisions, which were the prototype of the MACT provisions in the Clean AirAct [see 5 Legislative History at 8473-74 (Senate Report)], require control oftoxics reflecting performance of best technology, although the Clean Water Act gives EPA more flexibility to subcategorize than the Clean AirAct, since there is no floor provision, and EPA is required to consider manufacturing process, age, engineering aspects, costs, and types of control equipment (among other factors) in setting the standards. Clean WaterAct section 304 (b). Nonetheless, the Fifth Circuit rejected the argument that EPA erred in not subcategorizing based on different types of pollution control equipment: [P]etitioners' plants do not differ materially from other [chemical] plants with

respect to manufacturing operations orwastewater characteristics

.... Their plants differ only with respect to the type oftreatment petitioners voluntarily chose to employ. Petitioners did not choose to employ the type of

... treatment system that is most commonly used by good performers in the [chemical] industry

.... Instead, petitioners chose to employ

... treatment systems which generate additional pollutants

.... The EPA asserts that it therefore reasonably required petitioners' plants to meet the limitation demonstrated to be achievable by the 'best' plants in the industry, ratherthan providing less stringent limitations for these plants simply because they chose to employ less effective treatment technology

.... Petitioners cannot now be excused from meeting the BPT [Best Practicable

Technology] limits on the grounds that their present method oftreatment is less effective than the average ofthe best..

.. Such a construction of section 304 (b) (1) (B) would defeat the very purpose of establishing BPT limits. The EPA is not required to base BPT upon a technology that is less effective than the best


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## ( practicable technology demonstrated in the industrv

....We therefore hold that the EPA was entirely reasonable in declining to create a subcategory for plants employing [the less effective] treatment systems. Chemical Manufacturers Association v. EPA, 870 F. 2d 177,218-19 (5th Cir. 1989) (emphasis supplied), modfd on different grounds on rehearing, 885 F. 2d 253 (5th Cir. 1989).
This remains EPA's concern in the final rule. Subcategorizing purely on the basis of pollution control device type "would defeatthe very purpose of establishing [MACT]" because such a construction would mean the MACT floor would no longer reflect the performance of best performing sources, as required.
It has been suggested here, however, that the best performing sources with respect to HAP metal emissions should not be considered "best performing" because that performance comes at an environmental cost, namely increased emissions of HCI and S02 compared to what lime kilns equipped with wet scrubbers would emit. There is some support for the idea that if an ostensibly best performing pollution control device creates potentially counterproductive environmental effects, such performance need no longer be considered "best" due to the counterproductive effects, and could justify differentiation in the form of subcategorization (See 66 FR at 3187 [January 12, 2001]). Commenters suggest that is the case here due to increased emissions of HCI and S02 which would result (they maintain) if lime kilns replace wet scrubbers with baghouses. First, it is not clearthe commenters' starting premise, that baghouses are either needed orwill be used to achieve the PM standard, is correct. We continue to believe that a properly designed and operated wet scrubber can meetthe proposed PM emission limit of 0.12 Ib/tsf. The reasons for this are specifically addressed in our following response to comments on achievable wet scrubber performance.
The commenters provided no data to refute that application of a 0.12 Ib/tsf PM emission limit represents best control of HAP emissions ifwe do not create any kiln subcategories. We note that as part oftheir comments, they claim that the higher temperatures of dry PM controls result in metals vaporizing and passing through the PM control. However, the data provided in their comment does not substantiate their claim, and analyses performed for the Hazardous Waste Combustor NESHAP indicate that all but a few percent ofthe metals in question exit the kiln as solid particulate (see pages 1-1 through 1-4 in the Draft Technical Support Documentfor HWC MACT Standards, February 1996, which are in the docket for this rulemaking). The same comments stated that the increased PM emissions control that results from baghouses could be more than offset by increased fugitive dust emissions from dry systems. We know of no data that supports that statement. Dry dust systems can be designed and operated to minimize fugitive emissions. Moreover, we do know that fabric filters are commonly used when high levels of PM control are desired in many industries. In none ofthese cases do we know of any instance where less efficient wet scrubbers were applied in



### 3-4( lieu of more efficient fabric filters due to concerns offugitive dust emission from the collected particulate. We also evaluated the concerns that switching to dry controls may result in increases of S02 and HCI emissions. However, our analysis indicates that the extent to which S02 and HCI emissions actually increase may have been overstated by the commenter. EPA estimates that if all facilities currently using wet scrubbers switched to dry controls, HCI emissions would increase by approximately 

### 1,310 tpy (vs 

### 1,800 tpy estimated bythe commenter) and S02 emissions would increase by about 

### 1,830 tpy (vs 

### 2,900 tpy estimated by the commenter). (See the memorandum "Environmental Impacts of Decision on Best Control for Wet-Scrubber controlled Kilns" in the docket for this final rule).
We do not regard either level of increased HCI emissions as significant. We modeled this emissions increase as part of our determination (pursuant to section 

### 112 (d) (4» that emissions of HCI from lime kilns are below an HCI risk threshold, with an ample margin of safety. See FR 

### 78054

- 78057 and the risk analysis in the docket for the final rule. Given this determination, we cannot view these HCI increases as being so significant as to call into question whetherthe best-performing sources with respect to HAP metal reductions are in fact "best performing". 

## ( The commenters also cite projected increases in the criteria pollutant S02 that may result from our decision not to subcategorize by existing control device. They did not initially address the reductions in PM emissions resulting for the decision that 

### 0.12 Ib/tsfrepresents best-control for scrubber equipped kilns. We estimate that nearly 

### 1,080 tpy of additional PM would be removed if all existing kilns were to meet a standard of

### 0.12 Ib/tsf, ofwhich approXimately 

### 1.6 tpy are metal HAP. Although EPA may not promulgate standards for non-HAP under section 

### 112 (d), Congress expected reductions in emissions of criteria pollutants such as PM to be a benefit ofthe MACT program. 

### 5 Legislative History at 

### 8512 (Senate Report) ("When establishing technology-based standards underthis subsection, the Administrator may consider the benefits which result from control of air pollutants that are not listed but the emissions of which are, nevertheless, reduced by control technologies or practices necessary to meet the prescribed limitation [going on to give VOC reductions as an example].") In comparison to estimates of increased emissions of S02 by eitherthe commenter or EPA, the decrease in captured PM emissions (and attendant decrease in capture of non-mercury metal HAP) if all existing kilns are not required to meet a standard of

### 0.12 Ib/tsfis significant.
There is a further consideration, however. Based onthe available size distribution data from Compilation ofAirPollutantEmissionFactors, AP-42, FifthEdition, Volume I: Stationary Point andArea Sources, 73 percent ofthe PM emitteddirectlyby lime kilns is coarse PM (PM in the size range of2.5 to 10 micrometers). Some ofthe S02 emitted to the atmosphere undergoes chemical reactions to fonn fine PM. [See generallythe respective CriteriaDocuments forPM (EPA/600/P-95/001aF-cf. 3v, 1996) and S02 (EPA/600/8-82-029aF-cF. 3v., 1982 and addenda)].

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### ( Thus, in assessing whether some potential factor mightjustify a decisionthatkilns with dry systems are notbestperforming, some comparison ofcoarse verses fine PM emissions is needed.
Ifwe retain a single PM emission limit of0.12 lb/tsffor all existing kilns, total PM emissions would be reduced (compared to separate standards for kilns with wet scrubbers and dry controls) by an additional 1,080 tpy. Ofthatnumber, 630 tpy is fine PM and 450 is coarse PM. The potential amount ofincreased S02 emissions is 1,830 try. A portion ofthis 1,830tpy ofS02 will be converted inthe atmosphere to produce 1,270 tpy offine PM. Therefore, the incremental impactofa single PM standard ofO.12Ib/tsfforboth wet scrubbers and dry controls would be an increase of640 (l,270-630) tpy infine PM emissions, and a decrease of450 tpy in coarse PM emissions. This assumes that all facilities that currently have wet scrubbers switch to dry controls, and that46 percentofthe S02converts to fine PM. The 46 percentconversion estimate used by the commenter is consistent with information in the respective CriteriaDocuments for PM and S02 referenced above.
As recently summarized by EPA (68 FR28339, May 23,2003), scientific studies show ambientPM (both fine and coarse) is associated with a series ofadverse health effects. Fine PM is associated with increases in daily mortality. Coarse PM is more strongly linkedto morbidity (e.g. hospital admissions). See generallythe respective CriteriaDocuments for PM (EPA/6001P95/001aF-cF. 3v, 1996) and S02 (EPA/600/8-82-029aF-cF. 3v., 1982 and addenda). Therefore, it is difficult to make comparisons between the relative benefits ofreducing emissions offine and ( coarse PM.
We view this situation as equivocal: it is unclear which ofthese types ofperformance is best since on the one hand there is reduced emissions ofHAP metals and coarse PM but foregone control ofS02and sulfate (fme) PM, and, for kilns controlled with wet systems, the converse. In this situation, and based onthese facts, which, with current analytic tools seemto us to be largely in equipoise, we are notprepared to view either wet ordry systems as bestperforming and instead are promulgating a separate PM standard for each.
We emphasize that considerations ofrisk and relative environmental benefits are normally irrelevantto MACT floor determinations [unless expressly authorized by statute, as 

### in CleanAirAct (CAA) section 112(d)(4) as applied in the final rule], since floor standards must reflecttheperformance ofthe specifiednumber ofbestperforming sources. SeeNational Lime Ass'nv. EPA, 233 F. 3d at 640 (considerations ofcost and de minimis risk cannotbe considered in making MACT floor determinations). We consideredthese factors inthe final rule solely for the purpose ofevaluatingthe commenters' claimthat sources using wet and dry control systems should be evaluated separately for MACT floor purposes due to environmental benefits and disbenefits associated withwet and dry control systems. Giventhe equivocal facts here, we are notpreparedto state that eitherthe wet ordry systems are "bestperforming" for existing kilns, and are insteadpromulgating separate PM standards (as a surrogate for non-mercury HAP metals) for each. ( \ Comment

3-6

## ( Commenter IV-D-04 statedthat wet scrubbers cannotmeetthe proposed PM emission limit of0.12 lb/tsf. They claimedthat a wet scrubbermanufacturerwill only guarantee this limit ifless than 1 percentofthe particles to be removed are less than 1 micrometerin diameter. The commenter statedthat EPA assumes thatthe average mass diameterofparticles in lime kiln gas effluent is 2 micrometers, andthatthis assumption is basedon a single reference, and that reference was actually fugitive lime dust, not lime kilnparticulate. Theyfurther claimedthat volatilization andhomogenous nucleation ofpotassium chlorideparticles inthe gas stream generates particles inthe 0.1 to 0.5 micrometers sizerange. "As particle size decreases below 1 micrometer, inertial compactionbecomes decreasingly effective. Above 0.1 micrometers, Brownian displacement is ineffective. Inthe range between0.1 and 0.5 micrometers, neither of these two mainparticle capture mechanisms reliedupon in wet scrubber design is very effective." The commenter presents a recent example of a scrubber installation and an analysis of Docket item No. II-B-126 (an EPA memo titled "Technical Feasibility of Venturi Scrubbers in Meeting 0.12 Ib/ton Outlet PM Level") to demonstrate this point. Commenter IV-D-02 claimedthat a scrubberperformance efficiency of99.9 percent will be required to meetthe 0.0072 grain/dry standard cubic foot (gr/dscf) particulate concentrationwhich they claimedcorresponds to the proposed PM emission limit ofO.12Ib/tsf. The commenter's environmental consultantadvised that it is unlikely a wet scrubberwitha 35- inch water gauge (w.g.) pressure drop could achieve this level ofperformance withthe facility's currentinlet exhaustparticulate loading. 

### Response
We continue to believethat aproperly designed and operatedventuri wet scrubberwith a 35 inch w.g. pressure drop can achieve the proposed PM emission limit ofO.12Ib/tsf. The commenter argues thatEPA's basis for a 35 inch w.g. scrubberpressure drop to obtain 99.94 percent efficiency is not realistic. They base their arguments onperceived improperuse of estimationprocedures, incorrectchoice oftypical particle size, faulty vendorestimates, and lack ofknowledge regarding measurements ofan existing scrubberinVirginia.
This commentermisunderstands the mannerinwhichEPA evaluatedventuri scrubber performance. The particle size dataused inthe preliminary estimate came from several sources; not one as suggested bythe commenter. Second, ofthe various data available, we chose the data on fugitive lime dustPMbecause theyhad the smallestmean particle size diameter, which was 2 micrometers. This was avery conservative assumption, because, for anormal particle size distribution, the wet scrubberpressure drop requiredto meet a specific removal efficiency increases as the meanparticle size decreases. All the otherdatapresented in ouranalysis indicates thatthe mean particle size for lime kilnparticulate is much largerthanthe 2 micrometers we chose. Forexample, the particle size datareported inEPA's AP-42, Section 11.15, Lime Manufacturing, indicate thatthe meanparticle size for uncontrolledkilns is over 15 micrometers.
We used this atypically small particle size as a mediandiameterto input into simplified methods to estimate the pressure drop required to meet a scrubberPM removal efficiency of 99.94 percent (the removal efficiencyrequired to meet a 0.12Ib/tsfPM emissionlimit).
3-7

## ( The fIrst commenteralso assertedthatthe pressure drop estimationprocedure we used is inappropriate. The commenter statedthatin determining the required wet scrubberpressure drop 

### in aparticularapplication, theparticulate must be assigned to a setofdiscrete sizeranges andthe scrubbereffIciency evaluated at a specifIc pressure drop size range by size range. These results mustthen be used to calculate the overall PM removal effIciency.
We agree that, ifdata are available, the procedure described above is more accurate. However, we note thatthe commenterdid notprovide anyparticle size datathat would either substantiatethe contentions, or allowus to use the procedure claimedto be more accurate. In the absence ofthe type ofdata described bythe commenter, the conservative and simplified approachto estimating wet scrubberpressure drop used here, thatis, using a conservative estimate ofmedianparticle size, is reasonable. Therefore, based onthe data available, the procedure we have used to estimate what scrubberpressure drop, on average, will be necessaryto meet a 0.12 Ib/tsfPMemission limit, is suffIciently accurate. As explained, this procedure results in an estimatethat a 35-inchw.g. pressure drop is needed. However, as a check, we also contacted wet scrubbervendors to provide more rigorous estimates to confirm whetherthe 35-inch w.g. pressure drop value was valid. One vendor, using proprietary data, estimated a 35-inch w.g. pressure drop was sufficient provided there is sufficient moisture in the gas stream ahead ofthe venturi throat to increase particle size so that the venturi scrubber can remove the PM. We believe that the fact that two independent estimates produced the same result verifies our estimation procedure.
If necessary, cooling water can be added priorto the venturi in orderto sufficiently increase particle size. In some cases, more water can be added through a packed bed. Note that the cooled gas stream would have lower gas volume resulting in smallerfan, motor, and duct requirements.2
This same commenter presented data from a wet scrubber controlled calcimatic lime kiln indicating that potassium chloride in limestone leads to generation of a significant quantity of particles in the 0.1 to 0.3 micrometer range, which are difficult to collect in a wet scrubber. This wet scrubberwas designed for an outlet concentration of 

### 0.01 gr/dscfat a pressure drop of 22 inches w.g., but, after modifications, could only reach about 0.04 

### gr/dscf. The commenter asserted that it is "often the case" that 10 percent ofthe inlet loading to a lime kiln scrubber is in the 0.1 to 0.3 micrometer range.

2 Packed beds were not specifically costed out in our model kilns, but the additional cost for the packed bed (if ever needed) would be offset by the reduced cost ofthe fan, motor, and ductwork as well as reduced annual cost for powerthat result from the effect of gas cooling which reduces gas volume. However, some plants could possibly upgrade their existing scrubberfor about 40 percent ofthe cost of a new wet scrubber. In these cases, our model plant costs overstate capital cost by about 150 percent. On a nationwide basis, our scrubber costs probably overstate what actual costs are likely to be.


### 3-8( The commenter later provided data they claim supports this statement. The commenter cited this example to call into question EPA's conclusion that a wet scrubberwith a pressure drop of 35 inches ofwater can meet a 0.12 

### Ib/tsfPM emission limit. First, and most important, the example cited by the commenter can in no way be used to make generalized industry-wide conclusions about the ability ofwet scrubbers to meet a 0.12 Ib/tsf PM emission limit. The commenter did not include in their comments information from a BACT analysis for the Global facility (Global Chemstone Corporation, March 15,2002) writtenby the sameperson who wrote the commenter's statement regarding pressure drop and particle size. This BACT analysis states thatthe calcimatic kiln being controlledhas different characteristics thanthe more conventionally found rotarykiln. Statements aboutthe scrubber andkiln indicate thattheypresent aunique case, not likely to be found at other lime kiln sites. Examples are,

"

... the existing total filterable particulate matter emission limit of0.022 grains/dry standard cubic foot is too low given the unique issues associated with operating a calcimatic kiln with a moderate-to-highpotassium content limestone feed [363 parts per million (ppm)]." (p.l ofthe analysis)


## ( "Global has a Calcimatic lime kiln, which is fundamentally differentfrom atraditional rotary lime kiln." (p. 2 ofthe analysis) "However, there are significant differences between arotary lime kiln and calcimatic lime kiln." (p. 5 ofthe analysis)
"The dominantcharacteristic ofrotary lime kilns is the high concentration ofparticulate matter entrained inthe gas stream due to the directcontact ofthe hotflue gas with the tumbling feed materials within the kiln. This particulate matterprovides the surface area necessary for the condensation (heterogeneous nucleation) ofvaporphase materials. Potassium and othervaporphase materials inthe kiln gas streamwill concentrate primarily inmoderate-to-Iarge particulate matterthat canbe controlled with high efficiency wet scrubber systems." (p. 5 ofthe analysis)

"

... the particulate matter loadings from a calcimatic kiln are lowerthanthose ofarotary kiln. Due to the lowparticulate matterconcentrations inthe calcimatic kiln effluent gas streams, a significantfraction ofthe vaporphase potassium and othervaporphase material can condense (homogeneouslynucleate) to form submicrometer sizedparticles afterthe gas stream exits the kiln. Therefore, emissionfigures based onrotarykiln control equipmentare notrelevantto calcimatic lime kilns." (p. 6 ofthe analysis)

"

... areverse air fabric filter with membrane bags is technically infeasible at Global. The problems inherently involved with submicrometer sizedpotassium chloride also preclude the use of(l) reverse air fabric filters with conventional woven filter media and (2) pulse jetfabric filters with membrane-coated felted bags." (p, 8 ofthe analysis, note that fabric filters have beenused to control lime kilns for decades)


### 3-9

## ( "The Calcimatic kiln is more vulnerable to homogeneous nucleationthan rotarylime kilns due to the lowparticulatematterconcentrations inthe Calcimatic kiln effluent gas stream." (p. 11 ofthe analysis). Based onthese comments, it is clearthatthe situation atthe Global Stone Chemstone facility is unique, and not applicable to the industry as a whole. However, the informationpresentedhere could be used to implythat wet scrubbers are not as effective on calcimatic kilns as onto rotarykilns. (Note that calcimatic kilns make up only about 6percentofthe currently operating limekilns). However, as we have never claimed that a wet scrubberwith a 22 inch w.g. pressure drop can meet the proposed PM emission limit of 

### 0.12lb/tsf(as explained above, we estimated that a 35 inch W.g. pressure drop will be necessary), we do not see how the example cited by the commenter is relevant. Also, giventhe fact thatthe particle size data appearto have been collected afterthe scrubberwas installed, we conclude that thatthere are certain site specific factors that were not accountedfor in the scrubber design. However, this commenter goes on to claim that the wet scrubber in question could not meet a PM emission limit of 0.12 Ib/tsfeven ifthe pressure drop were increased to 35 inches. They claimed this is because ofthe presence of a large amount of particles in the 0.1 to 0.5 micrometer size range at this particularfacility, and that particles in this size range are the most difficult to collect with a wet scrubber. However, it should still be possible to meet 0.12 Ib/tsf even in this case, though additional costs for water injection orfor steam injection (to provide additional moisture in the exhaust gas) may be required. In that case, if a facility was required to meet a 0.12 Ib/tsf PM emission limit, it might opt for a fabric filter. Our model plant costing does not purport to predict how any individual kiln might'react. Finally, based on our determination that facilities that currently have wet scrubbers meeting 0.6 Ib/tsf are environmentally equivalent to dry controls meeting 0.12 Ib/tsf, the fact that this facility claimed it cannot meet 0.12 Ib/tsf is moot. Another point made bythis commenter concerned the choice of gas flow rate used for scrubber-equipped kiln modeling. From Information Collection Request (lCR) data available to EPA, exhaust gas flow rates for scrubber-equipped kilns were found to vary from about 100,000 actual cubic feet per minute (acfm)/ton of lime to about 310,000 acfm/ton of lime. The EPA chose an intermediate value of 165,000 acfm/ton of lime for modeling purposes (see docket item 11-8-14). There was no intent to choose eitherthe lowest or the highest flow rate in the database because on average, an intermediate value would be more representative. This commenter also stated that the value ofthe PM concentration in the flue gas was incorrect because we did not account for the water vaporfrom evaporation in the scrubber, and used a 800°F flue gas temperature. The concentration calculation was used to define inlet conditions to the model scrubber so that scrubber sizing and water requirements could be estimated by a vendor. The estimated PM concentration was not used in determining scrubber pressure drops, or in estimating costs.



### 3-10

## ( The second commenter supplied no data to support the assertion by their consultant that a 35-inch w.g. pressure drop scrubber could not achieve the required efficiency. Our responses above also address their comment. Comment Commenter IV-D-04 provided an analysis ofwet scrubberfeasibility prepared by a consultant to supplement their summarized comment above. This analysis raised several additional points not included in our previous comment response. These are as follows:
It took issue with the statement in Docket item No. 11-8-126 "Scrubbers have been reported to collect submicron particles as low as 0.006 grains per dry standard cubic foot in EPA's Handbook of Control Technologies for Hazardous Air Pollutants. The commenter pointed out that this statement concerned hydrosonic scrubbers.
It claimed the calculated PM concentration at the scrubber outlet equivalent to 0.12 Ib/tsfwas incorrect. The inlet mass loading data are limited.
The static pressure drop estimate is not applicable to bimodal distributions common to lime kilns. Response
The commenter correctly points out that the statement above related to hydrosonic scrubbers. However, this statement was only intended as an introductory statement in the memo. We based our analysis on our estimation ofthe performance ofventuri scrubbers. Therefore, the comment, though correct, is irrelevant.
The calculated PM concentration was not useo to estimate the required scrubber efficiency. The required scrubber efficiency was estimated based on mass emission rates. Therefore, the concentration value has no relevance to our estimate ofthe scrubber pressure drop required to meet a PM emission limit of 0.12 Ib/tsf.
We agree that the inlet loading PM data are limited. However, we believe that we have chosen a conservative value. We note that this commenter provided data elsewhere in their comments that indicated our estimate of 160 to 175 

### Ib/tsfmay be very conservative.
The commenter did not provide any data to support the statement that the particle size distribution from lime kilns is bimodal in the size range of 0.1 to 0.5 microns. The aerodynamic particle sizing information from the scrubber atthe Virginia site does not coverthe range below 0.5 microns. Apparentlythe commenteris basing the statement thatthe particle size distribution is bimodal on datafrom wet-scrubbercontrolled limekilns with


### 3-11

### ( high sodium feed rates inthepulp andpaperindustry. However, there are no datathat substantiate the commenter's statements for eithercalcimatic lime kilns, such as the kiln in Virginia, or for rotary lime kilns notinthe pulp andpaperindustry, which make up the bulkof the kilnpopulation. Comment Commenter IV-D-04 contends that EPA asserts incorrectly that lime plants will choose high efficiency venturi scrubbers to replace their current wet scrubbers because high efficiency venturi scrubbers have lower capital costs and sometimes lower annual costs than baghouses. Theyfurther stated that, according to Docket Item No. II-F-7, five ofthe six model kilns the Agency examined had much higherannualized costs for high efficiency venturi scrubbers than for baghouses. This commenter submitted a manufacturer's cost proposal that shows a scrubberwith a 35-inch w.g. pressure drop costs substantially more than EPA estimates. They conclude from this that lime kilns will be forced to use baghouses, with attendant increases in HCI and 

### 802emissions. Another commenter (IV-D-22) stated that the cost for the installation of a baghouse will be greaterthan EPA estimated due to the location of existing equipment in the area where the collector should be located, construction ofthe duct collector in a congested area with plant operations, and accessibility to existing lime kiln dust handling systems. Commenter IV-D-22 commented that the cost forthe installation of a baghouse will be more costly than EPA estimated due to the location of existing equipment in the area where the collector should be located, construction ofthe duct collector in a congested area with plant operations, and accessibility to existing lime kiln dust handling systems. Response Regarding modeled high costs for scrubbers compared to baghouses, individual models may showthis characteristic. However, the distribution of kiln sizes in the lime industry and the allocation of model plants to those kilns showthat estimated nationwide costs for installing venturi scrubbers is about the same as for installing baghouses. Tables 1 and 2 illustrate this condition.
In all cases, the estimated capital costfor each model scrubberis less than its corresponding model baghouse. Five ofthe nine models have estimated annual scrubber costs that exceedthe annual baghouse costs by amounts ranging from 4 percentto 75 percent. However, when model costs are convertedto national costs based on kilntype and size, the tables show a lower estimatedtotal annual costfor upgrades withventuri scrubbers than for upgrades with baghouses. Forbothtypes ofcontrol system, costs for any specificplantmay be more or less than the value shown bythe model used to estimate nationwide cost. The plant is expectedto buy whatever system its managementbelieves is inthe bestbusiness interests ofthe ( owners, butinthe aggregate, the tables indicate that estimated annual costfor control systems is lowerifall plants replace existing equipmentwith venturi scrubbers ratherthanbaghouses. However, based onthe specific model kiln costs, we still find that at least some kilns would replace wet systems with dry ifrequiredto meet a uniform PM emissions limit ofO.12Ib/tsf. 3-12

### (



## (

( We developed these model plants based on actual facility datafrom the industry responses to questionnaires. Ourmodel plants coverthe various types ofkilns currently in service, and arange ofsizes offacilities. Otherthan the commenton gas flow rates previously addressed, we received no comments thatthe model kilns are notrepresentative ofthe industry. The model plantparameters are generally based onthe mid-range ofthe characteristics ofthe segmentofthe existingkilnpopulationthatthey are designed to represent. Becausethey are based on mid-range values, comparing themto actual costs at anyone specific kilns mayresult in ahigherorlowercost estimate. However, there is no reasonable wayto model every individual kiln or account for every site-specific factor. Using model kilns based onmid-range values provides an accurate estimate ofthe nationwide costs, even ifcosts for some sites may deviate from the modeled estimates. Regarding acostproposal substantiallyhigherthan EPA's estimate for a scrubberwith 35-inchw.g. pressure drop, it is expectedthat someproposals will have higher costs, and some lower, than costs estimatedby EPA's methodology. The methodology is based on estimates of basic equipment costs, and factors to calculate direct and indirect capital costs that constitute total capital investment. Unit costs are appliedto labor, utilities, waste disposal, and other operating and maintenance costs to obtain direct annual costs. Indirect annualized costs based on capital recovery and other service charges are also estimated and added to direct annual costs to obtaintotal annual cost. The methodology is explained inthe EPA AirPollution Control Cost Manual. Forestablishing projected control costs inthe lime industry, the methodology was appliedto model plants having characteristics based on industryresponses to questionnaires. These model estimates account for all ofthe components neededto build and operate awet scrubber. However, the specific cost ofanyone componentin ourmodels, which are based on industry averages, maybe differentfrom those for a specificplant. Overall, ourmodel plant approach stillprovides areasonable estimate on whichto baseregulatory decisions.
The previous response also applies to the commentregarding installation ofa fabric filter that is projectedto costmore thanthemodel cost obtainedbyEPA. The cost estimation methodology for lime plants contains factors that accountfor demolition and salvage ofexisting equipmentthat will have to be replaced bythe new control system. A retrofit factor is also includedto account for difficulties inreplacing existing equipmentwithnew equipmentin an existingplant. As stated in theprevious paragraph, estimates made with model plants will not address each specific case found in industry. However, nationwide costs are reasonably estimated, and small business concerns, where they may appear, are addressed withinthe regulation.



### 3-13,,""'-'"**,~, ~,** 

Table 1. Costto Upgrade Existing Kilns Equipped with Wet Scrubbers to Venturi Scrubbers Model No. of kilns wIws* Model Kiln Capital Cost Model Kiln Annual Cost

kiln ($1000/kiln)* ($1000/kiln)*

A 4 252 113 8 5 288 131 C 14 520 293 

### o 11 663 403 G 1 301 146 H 1 499 278 I 0 682 420 L 1 351 180 M 4 177 64 Preliminary 41 Total
TOTAL (assuming 70% are major sources and 90% of scrubbers will upgrade)
*Source: Economic Impact Analysis forthe Lime Manufacturing MACT Standard, II-A-44. Total Capital Cost ($1000)

1,008 1,440 7,280 7,293 301 499



### o 351 708 18,880

11,894 Total Annual Cost ($1000)
452 655 4,102 4,433

146 278



### o 180 256 10,502

6,616

Table 2. Costto Upgrade Existing Kilns**E~ped-"vithWet** Scrubbers to Baghouses (wIwatersprays) Model No. of kilns wIws* Model Kiln Capital Cost Model Kiln Annual Cost Total Capital Cost

kiln ($1000/kiln)* ($1000/kiln)* ($1000) A* 4 790 204 3,160 8 5 859 225 4,295 C 14 1488 274 20,832 

### o 11 2824 386 31,064 G 1 558 90 558 H 1 984

. 71 984 I 0 2395 131 0 L* 1 665 237 665 M* 4 569 197 2,276 Preliminary 41 63,834 Total TOTAL (assuming 70% are major sources and 90% of scrubbers will upgrade) 40,215

* Model plant costs for models A, L, and M are the cost of baghouses plus cost ofwater injection (see 11-8-111).



### 3-14 Total Annual Cost ($1000)
816 1,125 3,836 4,246

90 71 

### o 210 788 11,182

7,045( Comment
Several commenters (IV-D-04, IV-D-06, and IV-D-12) statedthatnot establishing a subcategory for scrubber-equipped kilns will adversely affect small businesses. CommenterIVD-04 states the annualized cost ofupgrading all scrubbers is $9.45 million, based onthe distribution ofkilns andEPA's estimate oftotal annualized costs in DocketItemNo. I1-B-127. According to the commenter, EPApredicts that upgrading these kilns will reduce HAP metals by 3.1 tpy, resulting in a cost effectiveness of$3.0 million/ton ofmetal HAP. The commenter stated thatEPA's assumptionthat 30 percent oflime plants are area sources and won'tbe affected by the rule reduces the removal ofmetal HAP's attributedto upgrading scrubber-equippedkilns to 2.2 tpy (althoughthe commenter stated thatEPA has providedno support for the assumptionthat 30 percentoflime plants are area sources).
CommenterIV

-D-12 notes that EPA's estimated annualized costfor the commenterto install baghouses is $2,236,000, which equates to $9.3 millionperton ofparticulateHAP control. Response



## ( The comments state that requiringkilns currently controlledbywet scrubbers to meetthe proposed 0.12 lb. tsfPM emissionlimit is too costly considering the environmental benefits. However, section 112 ofthe CleanAirActprecludes us from considering costwhen calculating MACT floors. Therefore, none ofthe costissues discussed above are sufficientto support a separate subcategory for existing kilns with wet scrubbers. The commenters pointto no process orotherdifference which wouldpreventthem from achieving the level ofperformance attainable bythe average ofthe bestperforming existing sources, nor suggestthatthose bestperforming sources are unrepresentative ofotherkilns interms ofprocess, baseline emissions, orother factors which traditionally wouldjustify a separate subcategory. Though costs cannotnot be a considerationhere, our estimate shows a costof$7.15 million to upgrade all scrubbers, versus the $9.45 million figure providedby the commenter. Our estimate assumes 70 percent ofkilns are located atmajor sources and 90 percent of scrubbers will require anupgrade.
We also note that, inadditionto decreasing the emissions ofHAP metals, significantPM emissionreductions will resultfrom upgrading existing scrubbers. Upgrading the existing scrubber equipped kilns will reduce PM emissions by approximately 1,300 tons/yearfor an approximate cost effectiveness of$5,500/ton ofPM. The costperton ofreduction is reasonable comparedto other PM control regulations recentlypromulgated orproposed (such as the nonroad diesel engine rule). We acknowledge that, in individual cases, costs and costeffectiveness will vary and in some cases be higheror lowerdepending on individual circumstances.
In addition, in ourcost analysis, we assumedthat 90 percent ofexisting scrubbers would ( be replaced, and included all the capital costofreplacement inthe cost ofthe final rule. This is probably an overly conservative way ofestimating costs. Inreality, it is reasonable to assume
3-15

## ( that, on average, the existing scrubbers have only 50percentoftheiruseful liferemaining. Because we allocated all ofthe capital costofa new scrubberto the costofthe rule, ourcosts are conservative.
Comment
One commenter (IV-D-21) objects to EPA's rationale ofusing PM as a surrogate for controllingtoxic emissions. The commenter states thatifEPA has sufficientdatato indicate that toxic emissions from lime kilns are an ambient airproblem, thenthe regulation shouldfocus on reducing gaseous emissions such as HCI. Response By limiting emissions ofPM, the rule will reduce emissions ofnon-volatile and semivolatile metal HAP, which are a subsetofPM. As statedinthepreambleto the proposedrule, air pollution controls for HAP metals are the same as the PM controls used by the lime manufacturing industry, i.e., FF, ESP, and wet scrubbers. These controls capture non-volatile and semi-volatilemetal HAP non-preferentially along with otherPM, thus making PM an acceptable indicator ofthese HAP metals. Quite simply, "PM control technology indiscriminately captures HAP metals along with otherparticulates

....". National Lime Ass'nv. EPA, 233 F. 3d at 639. Consequently, it is an appropriate indicatorwhenthe technical basis of the standard is performance ofback-endparticulate controltechnology. Id. Anotherreason for using a surrogate is the lowercostofemissions testing andmonitoring for PM as comparedto the cost ofemissions testing and monitoring formultiple metal HAP thatwould berequired to demonstrate compliance. Because PM control devices control metal HAP to roughly the same efficiency, andbecause ofthe associated cost savings associated with emissions testing and monitoring, the Agencyhas promulgated several otherNESHAP where PM is a surrogatefor non-volatile and semi-volatile metal HAP. Regarding the commenter's second pointconcerning regulating emissions ofHCI, the preambleto theproposedrule explained in detail the Agency's decisionnotto regulate HCI emissions from lime kilns. To summarize thatdiscussion, the EPA determinedthat, underthe authority ofsection 112(d)(4) ofthe CAA, no further control was necessary because HCI is a thresholdpollutantand HCllevels emitted from limekilns are belowthe threshold value with an ample margin ofsafety, afterconsideringpotential threats to bothhumans andthe environment.

3-16

### ( Comment
One commenter (IV-D-12) requests a subcategory for theirunique mine chamberexhaustcontrol. Exhaust gas from the kilns is vented to an underground mine chamberwhich is unlike a baghouse orconventional scrubber, butfunctions like a scrubberdue to moisture in the mine. The typical exhausttemperatures atthe exhaust stackrange from 107 to 112 degrees F - well below 400 degrees F (aworkpractice temperature standardthathad been consideredbyEPA for HCI control, but was rejected). In addition, the condensationmoisture assures saturation ofthe exhaust stream and the contacttime exceeds those possible under any conventionalpollution control device. The commenteralso points outthatthe mine is not subjectto mechanical failures or operatorinducedmalfunctions as are conventional control devices. Accordingto the commenter, stacktesting done in 1995 demonstratedremoval efficiencies of98.9 percentfor PM, 99.1 percentfor S02, 52.3 percent forNOx, and 71.9 percentfor CO. According to the commenter, the cooling ofexhaustgases and subsequent condensation ofwater and the presence ofentrained water droplets makes continuous opacitymonitoring infeasible, which is why visible emissionreadings are currentlyperformed. The visible emission readings taken in the last several years show little variation and no exceedances ofthe applicable new source performance standards (NSPS) subpart HH kiln opacity standard of15 percent. 

### Response 

## (

( '. The commenteris requesting thattheiruse ofa mine as a PM control device for theirkiln exhausts be placed in a subcategory for wet scrubbers. But, as discussed above in aresponse to a previous comment, EPA has decided that itwill not develop a separate subcategory for wet scrubbers. Subcategorization is normallybased on differences in manufacturing process, emission characteristics, ortechnical feasibility and is notjustified solely on the basis ofa differenttype ofcontrol device being used. Underthis principal, the use ofa mine as an emission control device does notwarrant a separate subcategory.


### 3.2 PM Emission Limitfor Scrubber-Equipped Kilns
Comment
Inresponse to EPA's request for comments onwhat the MACT floor limit shouldbe if there was a subcategory for scrubber-equipped kilns, three commenters (IV-D-04, IV-D-06, and IV-D-16) state thatthe PM emission limitfor scrubber-equippedkilns shouldbe 0.6Ib/tsf. This is based on actual operational data and permit limits for the top 12 percentofthe existing kilns thatuse wet scrubbers for PM emissions control. These datawere compiledbythe National Lime Association (NLA) and providedto EPA.

3-17

### (

(

( Response
As discussed above, EPAhas determinedthat subcategorizing by existing controls is not appropriate. However, we have also determinedthatfrom an overall environmental standpoint, a wet scrubbermeeting an emission limitof0.60 lb/tsfcould be consideredbest control ifthe environmental disbenefits ofswitching to a drycontrol are considered. Therefore, we have setan emissionlimitof0.60 lb/tsfforkilns thatcurrentlyhave wet scrubbers for PM control.


### 3.3 PMEmission Limitfor New Kilns
Comment
One commenter (IV-D-04) states thatthe PM emissionlimitfor new lime kilns shouldbe 0.12Ib/tsf, the same as the emission limitfor existing kilns. The commenternotes thatthe proposed limit is based ontwo three-hourtestruns at oneplant. According to the commenter, EPArecognized inthe proposal preamble that 3-hourtestresults arejust a snapshotintime, and shouldnotbe used as the basis for establishing an enforceable standard, andthatEPA expressly rejected suchan approachwhen establishingthe MACT floor for existing kilns.
The commenterbelieves thatdatainthe docket shows that 0.10 lb/tsfis notcontinuously achievable by limekilns, and EPA shouldnotestablish a separate PM limit for new limekilns.
Anothercommenter (IV-D-16) believes 0.10 lbs PM/tsfforanewkiln is too restrictive, andEPA does nothave adequate datato determine that abaghouse or scrubber equippedkiln could achieve this lowlevel ofemissions on a sustainedbasis. 

### Response
The approachto which the commenterrefers whereby EPArejectedthe use ofthe "average ormean" in establishing the MACT floor for existing sources, didnotreferto the average ofindividual testruns as impliedbythe comment. Rather, itrefers to EPA's decisionto use the median (instead ofa simple mean) ofthe top performing 12percentto setthe MACT floor. Furthermore, as anindication ofthe achievability ofthe technology overthe long-term, EPA chose to rely on State-imposedpermitlimits (in conjunctionwith emissions test data showingthatthose permitlimits are representative ofactual performance) in arriving atthe MACT floor emissionlimit.
Intest datacited bythe commenter, the three-run averages for two sets ofemissions tests forthe kiln usedto setthe new source MACT PM limit, are below (0.079 and 0.091Ib/tsf) the proposed PM limitofO.1lb/tsffornew lime kilns. The commenternotedthat one ofthe test runs was attheproposed O.llb/tsfPM limitand thatthe proposed O.llb/tsflimitwas, therefore, inappropriate. (Itis, ofcourse, reasonable forEPA to establish a standardbased onthe same methodologythatwill be used for complying withthat standard. Cf. Chemical Waste Managementv. EPA, 976 F. 2d 2, 34 (D.C. Cir. 1992) (faciallyreasonable to require compliance based onmethodology usedto establishthe standard). EPA notes thatcompliance with emission

3-18

### (



## (

( limits is normallybased on athree-run average which can accommodate occasional elevated results as long as the average is atorbelowthe established limit. Furthermore, the emissiontest results forfive ofthe six top performing kilns were 0.0091,0.013,0.026,0.027, and 0.091Ib/tsf and are belowthe 0.10 Ib/tsfPM emissions limit. These results adequately account for operating variability and indicatethat any newkiln using well designed and operated control devices can meetthe O.1lb/tsflimit. Based onthis, we see no basis to concludethat a0.10 Ib/tsfPM emission limitis not achievable orappropriate. 

### Comment
One commenter (IV-D-06) claimed that the proposed NESHAP will require the replacement oftheir two wet scrubbers with baghouses. They claim there is no space for FF retrofit, and that converting to baghouses will trigger prevention of significant deterioration (PSD) non-attainment review due to increasedS02emissions. 

### Response
While we recognize that a facility may (or may not) have site-specific space restrictions, we have, on average, adequately accounted for these factors by incorporating cost analysis factors to account for retrofit and equipment demolition. We have also allowed existing facilities 3 years to comply with the final NESHAP. This will provide sufficient time for facilities to replace or upgrade existing equipment during scheduled outages. The averaging provisions in the final NESHAP also provide facilities with additional flexibility concerning replacement or upgrade ofexisting equipment. Requiring an existing kiln equipped with a wet scrubberto upgrade their PM controls will not necessarily trigger new source review (NSR). First, we have written the final rule to allow existing kilns equipped with wet scrubbers to meet a 0.60 

### Ib/tsf emission limit, rather then the 0.12 

### Ib/tsfPM emission limit. No commenters have raised any cost ortechnical issues to indicate that a PM emission limit of 0.60 

### Ib/tsfwill force any facilities to choose to convert existing kilns from wet scrubbers to dry controls. Therefore, the facility can choose to replace or upgrade their existing scrubbers, which means there will be no S02 (or other collateral pollutant) emissions increase to trigger NSR requirements. Second, ifthey choose to use a baghouse, they may be able to avoid NSR by qualifying for a pollution control project exclusion (67 FR 80186).

3-19

## (( 3.4 PM Emission Limit
- General
Comment
One commenter (IV

-D-14) believes the particulate matter emissionlimits proposedfor lime manufacturing kilns and coolers do notrepresentthe maximum achievable control technology and are much less stringentthanthe limits actually required by the CleanAirAct. The commenternotes thatthe proposedrule discredits performancetest datawhich demonstrate thatparticulate emissions ofless thanhalftheproposed standard for existing plants are routinely achieved by claiming they may notbe consistently achievable, butEPA has providedno statistics. The commenter claims thatEPAhas chosen insteadto base the standards onpermit limits, buthas selectively eliminated from considerationthose permits calling for stringent controls which are currently inplace. The commentergives the examples ofContinental Lime which is in compliance with aBACTlimitfor PM emissions of0.05 Ib/tonlimestone, and WesternLime which is in compliance with apermitlimit for PM emissions ofO.06Ib/ton limestone. The commenter states, "Consideringjustthese plants, arecalculation ofthe existing plant limitleads to a standard of0.09 to O.llib/ton. The new source MACT floor shouldbe no less stringentthan 0.05 lb/ton. However, ifEPA chooses to establish a MACT floor onthe basis ofpermitlimits, it should consider all ofthe permit datain its possession (and available to it through delegated State agencies). It is likelythat a loweremissionlimitwouldrepresentthe MACT floor andthat still lowerbeyond-the floor alternatives wouldresult."
The commenternotes thatifperformance data do notrepresent achievable emission limits, EPA shouldconsider design standards based on air-to-clothratios. The commenteralso believes the proposedparticulate emissionlimits for grinders, conveyors, andbins are also based on datawhich overstate emissions (innearly all cases) and do notrepresentMACT. The commenterbelieves EPA shouldexamine actual performancetestdatatestor actual permit limitations. 

### Response
The kilns to whichthe commenterrefers are GraymontWesternLime (formerly Continental Lime inBroadwaterCounty, Montana and WesternLime in Green Bay, Wisconsin. The permitlimits citedbythe commenterwere apparentlyreported onEPA Technology Transfer Network(TTN) website. We contactedthe MontanaDepartmentofEnvironment and found that the limitfor the kiln in question is actually0.5 lb/tsfandnot 0.05 lb/tsfas reported onthe TTN website. Also, the complete permitfor WesternLime was located onthe Wisconsin Department ofNatural Resources website, which showedthe permit limit for the kiln in question as being 0.12Ib/tsfratherthanthe 0.058 lb/tsfas reported onthe TTN website. Basedonthe correctPM permitlimits for these two lime sources, ourconclusions regarding MACT PM limits for existing and new sources are still appropriate. (As the response to aprevious comment shows, these permitlimits are also representative ofactualperformance.) The floor for grinders, conveyors, andbins are based onthe existing new source performance standards. We have no datato supporta differentfloor.

3-20

### ( 3.5 Monitoring Requirements for Scrubber-Equipped Kilns
Comment
Several commenters (IV-D-04, IV-D-06, and IV-D-22) commentthatthe rule should allowthe use ofscrubberpump amperage and otherindirectmeasures ofliquid flow rate. CommenterIV-D-04 takes issue withEPA's claimthatpressure drop and liquidflow rate are most often monitored scrubberparameters. The cornmenter states thatliquidflow rate is notthe most cornmon scrubberparametermeasured; inpart, because theNSPS for lime manufacturing requires the measurement ofthe liquid supplypressure to the control device. The commenter also states thatmostpermits for limeplants do notrequire that flow rate be measured directly, andprovidedpermitrequirements at existingplants to demonstrate this. Theynote that ofthe 8 limeplants that do have flow-related permitlimits, 5 ofthem are providedthe option of monitoring scrubberpump amperage instead offlow rate. The cornmenter also notes that ofthe four example CAM plans for scrubber-equippedkilns in EPA's CAM guidance, none includes liquid flow rate among theparameters to be monitored. The cornmenterrecommends thatthe rule allow liquid flow rate to be measured directly (e.g., with aflow meter) orindirectly (e.g., by monitoring scrubberexhausttemperature).



## ( One cornmenter (IV-D-04) believes the rule should allowthe use ofparameters otherthan gas pressure drop ifpre-approval from thepermitting authority is obtained. The commenter states that monitoring gas streampressure drop is not appropriate for all kilntypes. They use the example ofdouble shaftkilns, for which scrubberpressure drop is measurable only during the fuel firing cycle, returning to zero during the reversing cycle. In addition, the cornmenternotes that, "like the MACT standardfor lime kilns atpulp andpapermills, the lime MACT should be revised to allowthe use ofparameters otherthan gas pressure drop ifpre-approval from the state permitting agency is obtained." 

### Response The first commenter is correct in stating that the NSPS requires that the liquid supply pressure to the control device be monitored and not liquid flow rate. However, we note that scrubber-equipped lime kilns in other industries have requirements to monitor liquid flow rates to the scrubber. For example, the NESHAP for chemical recovery combustion sources at kraft, soda, sulfite, and stand-alone semi-chemical pulp mills requires that lime kilns (used in reprocessing black liquor at pulp and paper facilities) which are equipped with a wet scrubber must continuously monitorthe pressure drop as well as the scrubbing liquid flow rate. (See 66 FR 3196) The rule as proposed does allowthe owner or operatorto monitor alternative control device operating parameters subject to approval by the Administrator. Under the proposed rule, ifyou wish to request the use of an alternative monitoring method, you must submit a request following the procedures in General Provisions section 63.8(f). In orderto make this more obvious, we explicitly cross-reference this provision ( in the monitoring requirements ofthe rule. However, major modifications to monitoring



### 3-21

### ( requirements are not delegated. Therefore, decisions on this issue must be made on a case-by-case basis bythe Administrator as set out in 63.8(f).


### 3.6 Monitoring Requirements for Kilns With 

### Dry Air Pollution Control Devices


### Comment Several commenters (IV-D-04, IV-D-17, and IV-D-16) request that the proposed requirements in § 63.7113(d)(1) and (e)(1) that BLD and particulate monitoring devices (PMDl be certified by the manufacturerto be capable of detecting PM at or below 10 

### mg/m should be deleted because no specifications exist on which to base the certification. Commenter IV-D-04 notes that unlike COMS, there are no technical specifications, regulations, or checks and balances to verify claims made by the BLD or PMD vendor or manufacturer. 

### Response We disagree. The EPA is currently aware of instruments certified to meet levels of 0.2 

### mg/m3

. Specifications on which to base certifications are available in EPA guidance documents. 

### ( Comment

" One commenter (IV-D-04) states that the requirements in §63.7113(d)(6) and (e)(6) that BLD and PMD be "installed, operated, adjusted, and maintained so that they follow the manufacturer's written specifications and recommendations" should be revised to require adherence to the manufacturer's written specifications and operating procedures (ratherthan "recommendations") except where other procedures are determined to be more appropriate and are described and justified in the plant's operations, maintenance and monitoring (OM&M) plan. The commenter notedthat there is no industry-based consensus or EPA specifications, and "there certainly will be applications where the manufacturer's procedures or recommendations may not be appropriate or where a better approach can be used."



### (

3-22

## ( Response We agree that there may be cases where other procedures are more appropriate then the manufacturers recommendations. Forthis reason, we allow alternative monitoring underthe procedures in 63.8 (t). However, in general, we believe adherence to written specifications and recommendations is more appropriate. Therefore we have retained the requirements in §63.7113(d)(6) and (e)(6) in the final rule.


### Comment Several commenters (IV-D-04, IV-D-18, IV-D-17, IV-D-05, IV-D-16, IV-D-13, and IV-D-20) believe COMS should be retained as a monitoring option. Commenters IV-D04, IV-D-17, and IV-D-16 state that COMS are sensitive enough to detect changes in fabric filter performance at concentrations corresponding to the proposed PM limit and, unlike BLD, are subject to specifications that enable third party evaluation oftheir performance. Commenter IV-D-04 notes that COMS have been used to detect relative changes in particle mass loading for many years at lime plants. This commenter also states that, "actual COM data acquired at lime kilns with high efficiency filters demonstrate that COM data are appropriate and effective for detecting gradual changes in fabric filter performance over time." According to this commenter, EPA has suggested that BLD are preferable to COMS because they are more sensitive, but that all lime kilns currently equipped with CaMS are capable of meeting the sensitivity requirement proposed for BLD. Commenter IV-D-04 also noted that although the presence of bias makes any determination of absolute opacity below 10percent inaccurate, "it has no affect on the ability of a COMS to detect changes in opacity at a particularfacility

-- and hence changes in control equipment performance over time. Detecting relative changes in mass loading is all that BLD are capable of doing (preamble at 78062). COMS are more than adequate to detect changes in the opacity level necessary to detect minor variations in fabric filter or ESP performance well before catastrophic failures occur."
In addition, several commenters (IV-D-04, IV-D-18, IV-D-17, IV-D-05, and IV-D16) state that requiring only BLD would create unnecessary and duplicative monitoring since other CAA rules and permits require CaMS. Since the CAM rule requires that if a COM is required underthe CAA or state or local law, it must be used to satisfy the requirements ofthe CAM rule, requiring BLD or PMD would result in duplicative monitoring. 

### Response
EPA proposed that COMS be allowed as an alternative to BLD, PM detectors, and electrical current and voltage readings for ESP for monitoring continuous ( compliance with the proposed PM emission limits for lime kilns and coolers. EPA also
\ solicited comments on requiring the use of PM detectors and BLD in lieu of COMS. In


### 3-23

### (



## (

( response, several commenters stated their support for retaining COMS as a monitoring option. The commenters argued that COMS have a long history of use by the lime manufacturing industry and that they are effective for detecting changes in control device performance overtime. As a result, EPA sees no reason to not allow the use of COMS.
The commenters also claimed that requiring BLD or PM CEM would be redundant because the CAM rule requires COMS. The CAM rule only applies where a control device is used to comply with an emission limit proposed prior to November 15, 1990. Therefore, the CAM rule will not apply to monitoring requirements related to compliance with the Lime Manufacturing NESHAP.


### Comment One commenter (IV-D-04) commented that EPA should clarify that only COMS installed, relocated, or substantially refurbished after February 6, 2001 must comply with the version of PS-1 revised on August 10,2000. Because many COMS at lime plants were certified to meet the PS-1 requirements in effect at the time of installation, the commenter states that it is "impractical and cost prohibitive to remove these units from service for several months and return them for testing to the COM manufacturer. The cost to re-certify a single monitorwould exceed the cost of a new monitor due to the test regime specified in the ASTM standard." Response
The proposed rule states that you must install, operate, and maintain COMS as required by 40 CFR part 63, subpart A, General Provisions and according to PS-1 of Appendix B to part 60. The current version of PS-1 itself specifies that it only applies to COMS installed, relocated, or substantially refurbished after February 6,2001. However, this could result in the rule being unclear on the requirements for COMS installed on or before February 6, 2001. Therefore, we have clarified the rule to state that COMS installed, relocated, or substantially refurbished after February 6, 2001, must meet the requirements of PS-1 as revised on August 10, 2000. Any COMS installed on or before February 6, 2001, should continue to meet the requirements in effect at the time of installation unless the local regulatory agency specifically required recertification ofthe COMS in question. Comment One commenter (IV-D-19) states that opacity does not correlate to PM mass emissions. The commenter notes the EPA has stated on several occasions that STET systems (COMS) can determine opacity, but COMS cannot determine PM emissions. And if particle density changes but the particle size remains the same, opacitywill not change while the mass emission rate will change in proportion to the density change. The commenter agrees that PM is a technically sound surrogate for HAP metals, but



### 3-24

### ( disagrees that opacity serves as a surrogate for HAP metals as stated in the proposal preamble. The commenter does not believe that a COMS can be used to evaluate the continuous compliance status of kilns, coolers, or materials processing operations (MPO) that have a mass emission limit. The commenter is not aware ofany data that shows a definitive link between opacity and mass emissions except in very limited and controlled situations. In addition, the commenter does not understand how a 

### 15 percent 6-minute average opacity limit can be correlated to a 3-hour rolling average PM emission limit of Ib/ton of stone feed. The commenter states, "the error in using a COMS to determine compliance with the PM mass emission limit can be demonstrated from the data presented to you by the National Lime Association. If one ofthe top performing lime kilns has a measured emission rate well belowthe 0.12 Ib/ton offeed emission limit, but has a reportable opacity between 10 and 15 percent, there can be no correlation."



## (

( The commenter believed a better alternative is to use a monitorthat measures PM mass emissions in units that are directly related to the mass emission limit. The EPA should consider using a PM continuous emissions monitor (CEM) for continuous compliance determination of kiln, cooler, and MPO emissions with orwithout a PM CEM performance specification. The commenter notes that EPA's stated reluctance to use a PM CEM in the absence of performance specifications is inconsistent with the remainder ofthe standard, since the use of bag leak detector systems (BLDS) and a PM detector are proposed without performance specifications. The commenter also notes that an extractive type PM CEM designed to operate in wet exhaust streams would provide a direct indication of compliance for wet scrubbers. Response
We agree that a COMS cannot directly measure PM emissions. However, we believe that aproperly calibrated and maintained COMS is sufficientto demonstrate longtermPM control device performance. The purpose ofthe monitoris to demonstrate, withreasonable certainty, thatthe PM control device is operating as well as itdid during the PM emissiontestused to demonstrate compliance. Though we agree that acontinuous monitorthatdirectlymeasures PM emissions wouldprovide direct evidence ifthe PM emission limit is exceeded, we have no data to demonstrate thatthis would result in additional PM emissions reductions compared to monitoring the control device with a COMS. Therefore, requiring facilities to remove their currently installed COMS andreplace them with aPM CEM only adds additional costs with no quantitative environmental benefit. We also note that we know ofno lime kiln thatcurrently has an operating PM CEM.
Comment



### 3-25

### ( One commenter (IV-D-19) provided comments onthe cost ofPM CEM. The commenter provides costdatafor several monitortechnologies, and notes thatthe listprice is onlypart ofthe costofinstalling and using aPM CEM. 

### Response
We thank the commenterfor this additional data. However, because we are not requiring PM CEM as a monitoring option, we are assuming that facilities will opt to use a CaMS due to the lower costs. Because most existing facilities already have a CaMS installed, we have not revised our rule costs to incorporate this data.


### Comment
On commenter (IV-D-19) provided comments onthe relation ofaPM CEMrequirement to the proposedPM emissionlimits. The commenter sees no reasonto change the proposed level oraveraging time ofthe PM emission limitifa CEM is used. The commenter suggests having a lime manufacturing plantpurchase, install, and operate a PM CEM to monitoremissions over a period oftime (e.g., 6 months) to confrrmthe proposed limitand averaging intervaL 

### Response ( Since we believe that the monitoring options ofthe proposed rule are adequate to show good operation of emissions control devices, it is not necessary to perform testing using a PM GEM.


### Comment One commenter (IV-D-04) states that PM GEM should not be required in the lime MACT because EPA has no data on which to establish an achievable CEM-based PM limit. 

### Response
We disagree. Because PM CEM directly measure the PM emission rate, the appropriate limitwould be 

### 0.12lb/tsf(existing sources) or 0.10 

### Ib/tsf(new sources). However, we are not requiring PM CEM, they are an option. 

### Comment
Gommenter IV-D-19 believes that EPA needs to include beta gauge and optical scintillation along with light scattering technology for the PM detector. 

### ( 

### Response

3-26( The final rule allows use ofPM CEM as an option. ShouldPM CEM be used, they must meet appropriate performance specifications. Anytype ofPM CEM, including thosethatrely on betagauges oroptical scintillation, thatmeets the performance specifications maybe used. Comment Several commenters (IV-D-04, IV-D-18, IV-D-06, IV-D-11, and IV-D-09) believe EPA Method 9 should be allowed for positive pressure baghouses. According to commenter IV-D-04, the BLD Guidance Document recognizes that requiring BLD would be very costly, and states that the document does not apply to this type of baghouse (BLD Guidance Document, pg 2). This commenter gives the example of a small business (Austin White Lime) that would be required to have a BLD for each ofthe 8 compartments in its baghouse underthe proposed rule, and whose Title V permit allows Method 9 monitoring for the baghouse. According to commenter IV-D-09, the associated costs of installing a separate BLD or PM CEM sensor on each discharge or new common stack could easily exceed $1,000,000. The commenter notes that, "baghouse pressure differential readings, togetherwith fan amperage and daily visible emission notations (Method 22) will provide the necessary performance assurance with ample and timely indication of baghouse failures or malfunctions." Response ( We acknowledge that there are precedents for the use of alternatives to COMS, BLD, and PM CEM on positive pressure baghouses that have multiple stacks. The NESHAP for portland cement, an industry that has similarities to the lime manufacturing industry, allows the use of method 9 opacity monitoring for kilns having control devices with multiple stacks. For existing lime kilns controlled by positive pressure control devices having multiple stacks, the final rule provides the option of using method 9 for daily opacity monitoring. We are also revising the rule to allow Method 9 monitoring if the control device vents through a monovent, or if installation of a COM in accordance with PS-1 is infeasible. Comment One commenter (IV-D-04) believes that COMS should be used as the monitoring option for ESP. The commenter claims that using PM detectors on ESP is problematic, as is parametric monitoring ifthe ESP is over-designed such that operating at or above the voltage levels measured during the performance test is not needed to maintain compliance with the PM limit. One commenter (IV-D-19) comments that there are no data to support the use of ESP operating parameters to determining compliance. The commenter notes that until the lime industry collects this data in three-hour rolling averages for extended periods of time in a reportable format that can be analyzed by others, no conclusions can be made ( regarding the usefulness of ESP operating parameters in determining compliance or mass emissions.


### 3-27( \,



## (

( 

### Response
We agree with the commenters that COMS and PM CEM should be sued to monitorthe performance of an ESP. Therefore we have modified the final rule ro require a COMS or PM CEM to be used to demonstrate continuous compliance. Because we are now requiring COMS or PM CEM, monitoring ESP voltage and current is not be required. 

### Comment One commenter (IV-0-09) believes that stack testing on positive pressure baghouses should not be required. The commenter notes that the eight stacks at each of its positive pressure baghouses are nearly inaccessible and too short to be properly tested, and "attempting a performance test

...would be dangerous without significant additional improvements

... , "and, "the cost of all ofthese improvements could exceed $1,000,000." The commenter believes positive pressure baghouses with multiple inaccessible stacks should be given the option to perform a 3-hour Method 9 performance test when operated in conjunction with performance monitoring. 

### Response
EPA regulations generally require, at a minimum, initial performance testing to demonstrate compliance with emission limits for affected sources. Further, the General Provisions section 63.7(d) require sources to provide adequate testing. Positive pressure baghouses are used in many ofthe industries that are subject to EPA regulations and are required to conduct performance testing in order to demonstrate compliance. EPA has developed procedures for testing PM emissions from various configurations of positive pressure baghouses, which are contained in Method 50 of40 CFR part 60, appendixA. Therefore, we have decided not to alterthe compliance requirements for sources using positive pressure bagh6uses. 

### Comment
One commenter (IV-0-19) does not understand how an alarm level will be set for a PM detector or a BLO system that will have any correlation to a PM emission limit in units of 

### Ib/ton ofstone feed. The commenter states that an extensive amount of testing overvarying conditions at or near the limitwould be needed to establish the response of BLO or PM detectors as a function of actual PM emissions. The commenter also notes that EPA's bag leak detector guidance does not provide such procedures. 

### Response

3-28

## ( We have not stated that BLD limits and PM limits correlate. BLD are calibrated at the time the PM emission test is run. The BLD then detects changes in performance verses performance during the PM emission test.


### 3.7 Operating Parameters
Comment
One commenter (IV-D-04) states that a single excursionfrom operatingparameters recorded during a 3-hourcompliance test shouldnot constitute a violation. The commenter believes that, "theNSPS kilns are the lime industry's top performers, and theirmonitoring regime shouldbethe benchmark againstwhich monitoring underthe MACT rule is prescribed." Since a violationunder theNSPS does not occurunless the parameteris greaterthan 30 percent belowthe rates established during the performancetest, the commenterrecommends a 30percent "buffer" betweenthe permit limit and the 3-hour average recorded during the compliance test. Or, "alternatively, like the Pulp and PaperMACT, the rule should specify that a violation ofthe standard does not occurunless 6 ormore 3-houraverage parametervalues are recorded outside the establishedrange withinthe 6 monthreporting period." The commenter notes that EPA's CAM guidance document states, "Use of only 3 hours of parameter data may not be sufficient to fully characterize parametervalues during normal operation." The commenter also noted that language in the proposal preamble cautions against developing enforceable emission standards based on 3-hour compliance tests. The commenter also notes that none ofthe CAM plans for scrubbers base a permit limit on the 3-hour average reading that occurred during a compliance test, and two ofthe plans allow a 15 percent bufferto account forvariability. The commenter provided gas pressure drop readings and concurrent PM test data for three kilns, and noted that for each ofthem, gas pressure drop during one or more 1-hour runs was below the proposed 3-hour average. The commenter stated that underthe proposed rules, these readings below the 3-hour average would constitute a violation. The commenter also believes the rule should provide an exemption from the PM emission limit during performance testing. The commenter stated, "plant operators may need to conduct a series of performance tests to determine the minimum pressure drop and liquid flow rate levels that will assure compliance for each set of operating conditions used for a particular kiln. Results for these tests are not available until posttest laboratory analyses are completed." 

### Response Each owner/operator is required to define the compliance parameters to be monitored in their OM&M plan. Then, during the initial performance tests they are required to monitor and establish the value or range ofthe parameters. EPA believes that the initial performance tests will be designed to give the owner or operator flexibility in adhering to the established range for monitored parameters. These values must be


### 3-29

## (



## ( reported in the results ofthe test and in the notification ofcompliance status to the permitting authority and must be approved by the permitting authority. During subsequent operations, ifthe monitored parameters exceed the values orfall outside the range determined during the initial performance test, it is a violation ofthe operating requirements ofthe standard (unless it is the result of a malfunction to which the facility responds to in accordance with the startup, shut down, and malfunction [SSM] plan). We have has no basis for allowing deviations before considering the facility to be in violation. The owner/operator has ample opportunity to establish a range for the operating parameters and must thereafter operate within that range. Most operating parameters are calculated as 3-hour averages. This is generally consistent with performance test times. Thus, a one-hour period of insufficient gas pressure drop would not, by itself, be considered a deviation.


### Comment
One cornmenter (IV-D-04) stated that the accuracy criteria in Table 4 (items 8, 9, 13, and 14) for devices used to measure operating parameters should be deleted. The commenter notes that the lime MACT is unique because it includes both accuracy and minimum tolerance criteria for measurement devices; other recent MACT rules contain only tolerance criteria. In addition, the commenter states that EPA has offered no explanation for the proposed accuracy criteria in Table 4. The commenter believes it is the precision ofa device (Le., the value of a parameter relative to what was recorded during the performance test) that is important in the context ofthe lime MACT, not its accuracy. 

### Response We disagree. We commonly include accuracy criteria in MACT standards for devices used to measure operating parameters. We continue to believe that monitoring devices of known accuracies should be used. 

### 3.8 Opacity Limit


### Comment
In response to EPA's request for comments on the appropriate opacity limit (EPA is considering an opacity of 10 to 15 percent), several commenters (IV-D-04, IV-D-18, IV-D-17, and IV-D-16) agree that the opacity standard for lime kilns should be 15 percent as proposed. One commenter (IV-D-04) provided additional data in the form of opacity data from four kilns. According to this commenter, the opacity data for selected kilns (Docket Item No. 1-8-125) are not reliable for establishing an opacity standard because they are from visible emission data collected for brief periods oftime under poorviewing conditions. Response



### 3-30( Based on information considered prior to proposal as well as additional information supplied by commenters, EPA is retaining the 15 percent opacity limit for sources controlled using FF and ESP. Information considered by EPA in proposing the opacity limit suggested that the average opacity permit limit ofthe top performing lime kilns was 15 percent. Information provided by the commenters supporting the proposed opacity limit indicated that opacity levels may vary between 10 and 15 percent even for well operated and maintained control devices. No information supporting a more stringent opacity limit than the one proposed was submitted by any commenter. Therefore, EPA finds nojustification for a limit more stringent than the proposed 15 percent. Comment Several commenters (IV-D-04, IV-D-18, IV-D-17, IV-D-07, IV-D-05, and IV-D-13) state that the rule should specify a time period during which opacity readings greater than 15 percent are not considered a violation. One commenter (IV-D-04) requests at a minimum that the rule state that opacity readings greater than 15 percent for less than 1 percent ofthe reporting period are not considered to be a violation. One commenter (IV-D-07) noted that it operates two ofthe top six performers in the industry, and it is impossible not to have occasional readings that would be violations ifthere were no allowances for them. The commenter's State permits allow 1 ( percent of operating time per quarterto exceed the opacity limit.

" Commenter IV-D-05 requests that the final rule state that a particulate matter violation has occurred if: (1) opacity readings exceed the15 percent opacity limit for 6 percent or more ofthe operating time in a quarter or, (2) opacity readings exceed the 15 percent opacity limit for 20 total hours in a quarter, whichever time frame is longer. Commenters IV-D-04 and IV-D-05 refer to the Pulp and Paper MACT as an example of an existing rule with such an exemption. Response We find nojustification to support allowing excursions above the 15 percent opacity limit. We believe that well operated and maintained control devices will typically operate at opacity levels much lowerthan 15 percent. Other NESHAP, including the portland cement NESHAP, contain opacity limits from which no exceedances are allowed.
In response to the commenters' concerns about occasional excursions above the opacity limit, there are times when opacity levels above 15 percent are not considered to be a violation ofthe rule. These include periods when a control device malfunctions, or is in a period of startup or shutdown. Ifopacity levels exceed 15 percent as a result of a control device startup, shutdown, or malfunction, it would not be considered a violation ofthe opacity limit. The same is true during periods when a monitoring system


### 3-31

### (



## ( malfunctions or is being calibrated; provided the startup, shutdown, and malfunction (SSM) plan is followed. Information supplied by one commenter showed opacity readings for several kilns over several days. Nearly all ofthe readings were well below the 15 percent limit with just a few exceptions for each kiln. The commenterthat supplied the opacity readings was asked to supply additional information regarding the opacity excursions above 15 percent. In each instance, the high opacity reading was explained by a startup, shutdown, or malfunction ofthe control device or by a malfunctioning monitor or a monitoring system that was undergoing calibration, none of which would be considered a violation ofthe opacity limit. As a result, we believe that well operated and maintained control devices can meet the opacity limit, and that occasional excursions above the limit due to control device or monitoring system malfunction will not be a violation ofthe rule provided the SSM is followed.


### 3.9 Stone Handling Operations Comment Several commenters (IV-D-04, IV-D-17, and IV-D-11) request that the terms "raw material processing" or "material processing operation (MPO)" be replaced with the term "processed stone handling" since the only ingredient used to make lime is processed limestone. Commenter IV-D-11 noted that the use of "raw material" could be construed to include unprocessed stone and thus potentially include stone handling operations in the quarry. Commenter IV-D-09 notes "the exclusion ofstorage piles from this proposed NESHAP is consistent with other standards such as the Portland Cement Manufacturing MACT, Integrated Iron and Steel Manufacturing MACT and the Nonmetallic Minerals Processing Plants (Subpart 000) NSPS." The commenter believes that storage piles prior to any processing operation are a continuation of raw material handling and should be exempt from the MACT.



### Response

Comment Several commenters (IV-D-04, IV-D-17, IV-D-16, and IV-D-11) commented that the definition of "storage bin" in 

### § 63.7143 should be revised to clarify that bins are manmade enclosures used to store processed stone feed for the kiln. Commenter IV
### 3-32( 0-04 noted that this is consistent with the definition in the cement MACT, and that it clarifies that storage piles are not subject to the rule. Commenters IV-0-04 and IV-0-16 recommend the following amended definition: "A manmade enclosure for storage of processed limestone prior to its use as lime kiln feed." 

### Response
The rule has been revised to darify that storage bins refer to manmade bins for storage of processed limestone. 

### Comment One commenter (IV-0-04) believes the rule should not require the use of proposed Methods 203A, 203B, and/or 203C to measure opacity from fugitive sources. The commenter notes that the preamble does not state why Method 9 is unsuitable, "nor does it specify how Methods 203A,B, or C would be used and what the corresponding opacity limit would be. 

### Response


## (

(

, We requested comment in the proposed rule on the use of proposed Methods 203A, 203B, and/or 203C to measure opacity from fugitive sources. We never stated that Method 9 was unsuitable. We were concerned that because Method 9 was developed to measure emissions from stacks, and an alternative method might be more suitable. We have decided not to allowthe use of proposed Methods 203A, 203B, and/or 203C in the final rule. However, we have added additional language to the final rule to explain how to use Method 9 to determine opacityfrom fugitive sources. This language was taken directly from 40 CFR 60, subpart 

### 000, Standards of Performance for Nonmetallic Mineral Processing Plants. 

### Comment
Two commenters (IV-0-04 and IV-0-17) request section 63.7120(b) be revised to clarify that periodic (not continuous) monitoring is required for stone handling units. 

### Response
EPA has revised the rule to clarify that stone handling operations are generally subject to monthlyvisible emissions testing and not continuous monitoring.



### 3-33

### (



## ( 3.10 Test Methods Comment Several commenters (IV-D-04, IV-D-05, and IV-D-08) asked that EPA delete the bias and precision criteria for HCI test results using ASTM Method. Commenter IV-D04 states, "the commercial lime industry has invested substantial resources to develop a method to address EPA's concern that Method 26 understates HCI emissions. An ASTM committee has concluded that Method D 6735-01 generates data that has no statistically significant bias. It is arbitrary and unreasonable for the Agency to burden the commercial lime industry

- half of which is comprised of small businesses

- with a requirement to conduct analyte spiking to prove that HCI test results are unbiased. Likewise, requiring paired runs to comply with a precision criteria is not warranted because (1) EPA has never raised any concerns about the precision of impinger generated HCI data, and (2) ASTM Committee D22 on Sampling and Testing of Atmospheres approved the impinger-based method after evaluating the precision ofthe data generated with the method. Accordingly, the bias and precision criteria for HCI test results obtained using ASTM Method D6735-01 should be deleted from the rule." Commenter IV-D-05 notes that these criteria are not found in the ASTM method. 

### Response The ASTM validation proved that, when ASTM Method D6735-01 is conducted properly, it is possible that data are not biased. However, because the ASTM method lacks precision, the power ofthis conclusion is not very strong. The validation does not assure that future applications ofthe method run by another group will also be unbiased. Sampling for HCI in a lime plant environment is difficult. The purpose.of analyte spiking is to assure that a representative sample is transported from the stack through the probe and filter to the impingers regardless ofwho is performing the test. Analyte spiking is an option in the ASTM procedure; because ofthe importance ofthe decision made as result ofthis data, we chose to exercise that quality assurance option. We agree with the commenters that analyte spiking is a complex procedure. However, it is a requirement ofthe Method 320 instrumental FTIR method which we believe is superior. There is no reason to allow less quality assurance forthe inferior method. However, we agree with the commenterthat forthe purpose of determining major/area status, it is not necessary to reject a set of data ifthe apparent bias does not change the major/area source determination.
With respect to the commenters' suggestion that the precision criterion be deleted, EPA disagrees. It is an option in the ASTM procedure which EPA chose to require. Reasonable agreement between paired samples is considered a strong indication that the method is being consistently operated, recovered and analyzed. One commenter (IV-D-04) cited section 6.3.1.2 (of EPA Method 301) as the EPA precision criteria for an acceptable alternative method. They mistakenly thought the proposed rule would impose a much more stringent precision criteria (i.e. 50 percent


### 3-34( RSO). In fact, when an acceptable method already exists (as in this case), Section 6.2 of EPA Method 301 applies, which requires a candidate alternative method to be at least as precise as the method forwhich it is intended to be substituted. However, because the industry is reluctant to embrace the use ofthe acceptable method (EPA Method 320 or 321), we waived the requirement that the alternative method to be at least as precise (as allowed by section 1.1.1 of EPA Method 301). Therefore, in order to allow the use ofthe less precise ASTM method, we instead chose to have the testers demonstrate their ability to get reasonable agreement at the actual facility. Note 3 in section 4.1.4 ofthe ASTM method reinforces this approach in that it states "The particulate matter of mineral calcining facilities adsorbed HCI and HF to varying degrees. The amount of adsorption depends on process parameters and the physical/chemical properties ofthe dust." 

### Comment Commenters IV-0-05 and IV-0-08 note that ASTM Method 06735-01 includes optional paired train and spiking procedures. The commenter is unclearwhat basis EPA has used to make these optional procedures mandatory. 

### Response 

## ( We disagree. Exactly because it is an option to use paired trains and analyte spiking procedures in the ASTM method, EPA clarified that for this application those options were exercised. Section 5.4 ofthe ASTM method states "the test specific precision may be determined by conducting paired runs." Paired runs aid in identifying possible suspect data and provide backup in the event one train is invalidated. Performing paired runs depends on the test specific data quality objectives. Section 5.3 has a similar statement regarding analyte spiking. In the bigger picture, ifthe only options available to us were to accept or reject an ASTM method with no alterations, we would have to reject many more ASTM methods for relatively easily corrected reasons. This would severely limit our good-faith implementation ofthe National Technology Transfer and Advancement Act. 

### Comment Commenter IV-0-08 notes that there is no discussion in the proposal preamble explaining where the 20 percent limit for absolute relative standard deviation (RSO) came from. The commenter requests that the requirement be deleted,since the ASTM method does not mention criteria for accepting or rejecting a test, and since the ASTM results are completely consistent with EPA's own RSO criteria of 50 percent. If EPA insists on including the paired train requirement and an associated RSO criterion, the commenter believes a ppm difference should be considered, particularly for low concentration sources. The commenter suggests that ifthe RSO exceeds 50 percent, the results continue to be valid provided the absolute difference between the two train ( values is 3 ppm or less.



### 3-35

### (



## ( Commenter IV-0-05 requests that the ASTM method be incorporated by reference as it is written. 

### Response
We agree with the commentator that it may not be necessary to reject data with poor precision if it doesn't affect the major/area source decision. However, we disagree that the way to attain this goal is to provide an absolute value that is acceptable regardless of how close to the action level the data are. 

### Comment
Commenter IV-0-08 stated that the regulation would require four valid runs, which are too many, noting that nearly all methods require three runs and not four. The commenters states that the ASTM method defines the test to be three or more runs and that EPA should have the same wording. Commenter IV-0-05 asked that if a spiking procedure and spike recovery criterion are included in the final rule, that we confirm that the three test-run requirement ofthe ASTM method is met with two non-spiked runs and a third, spiked run. 

### Response
As discussed above, EPA disagrees that we are confined to exactly what the ASTM method states. In this case the ASTM method merely sets a minimum ofthree. However, in this case EPA, agrees that three or more runs may constitute a test. Our intent is that two ofthe three runs be made with paired trains, and one run be made with paired trains where one train is spiked. 

### Comment One commenter (IV-0-10) believes ASTM D6735-01 to be a "primitive" or inferior measurement technique, and EPA Method 320 (FTIR) to be a clearly superior method for HCI measurements. The commenter notes that EPA Method 320 directly measures HCI, while 06735-01 measures total chloride. There is no need to conduct indirect measurements, since there is a reliable test method that directly measures HCI.
The commenter states that EPA Method 320 has a typical RSO of approximately 1 to 2 percent compared to 30 to 50 percent RSO for 06735-01. The commenter provides cost data for EPA Method 320, and notes that the methods (EPA Method 320 and ASTM 06735-01) have virtually identical costs. The commenter urges EPAto require the use of EPA Method 320 for lime HCI measurements. 

### ( Response

3-36( We agree that FTIR is the best choice oftest method to measure emissions of Hel, and note that the cost estimate provided by the commenter is close to the EPA estimate of cost to perform the ASTM method. However, we feel that the EPA can use data from a properly conducted ASTM 06735-01 test to determine ifthe source qualifies as an area source. We agree that there is a potential to incorrectly conclude that the source is major, when in fact, it is not. 

### 3.11 Economic Impact Analysis Comment One commenter (IV-0-06) claimed that the econimic impacts analysis (EIA) neglected to include some significantcosts of implementing the proposed rule, including the cost of dismantling existing equipment, lost sales during downtime, and the cost of re-hiring personnel after plant modifications if scrubbers must be replaced. The commenter also noted that maintenance and supervisory personnel currently do not work evening and weekend shifts, but would likely be required in the event offailure ofthe recommended monitoring equipment. Another commenter (IV-0-02) believes EPA's estimated $1.17 per ton of lime cost estimate is low, and the cost to a typical lime producerwill be significantly higher. In particular, the commenter noted that the additional power required for high pressure ( drop scrubbers alone would be approximately $1.30 per ton of produced lime. In addition, EPA's estimated equipment costs appear to be low. 

### Response
The commenters believe eitherthat implementation costs (IV

-D-06) orpowercosts (IVD-02) are notproperly represented. As discussed inthe response to comments regarding a separate subcategory for scrubbers, estimated implementation costs used for the EPAmodel plants include costsfor demolition ofexisting equipment and credits for salvage value. Because plants have athree-yearperiod inwhich to comply with the proposedrule, itis expectedthat scheduled downtime will be used for disconnecting an existing scrubberand connecting anew scrubber. As a general practice, building anew scrubberwhile the existing scrubberremains in operation.is preferableto taking the associatedkiln out ofservice for an extendedperiod oftime and losingproductionfrom the kiln. The plantis expectedto use its laborforce in the manner normally found forplanned downtime. Such laborcosts (or savings) would notbe attributable to compliance with the proposedrule.



### ( Powercosts for new scrubbers are costedincrementally, i.e., costs are estimated for the difference between 35 in. w.g. (new scrubbers) and 14 in. w.g. (existing scrubbers) as used in DocketItemNo. II-B-122. Forindividual model kilns, summing the powercosts and dividing by the model's productionrate gives estimated incremental powercosts ranging from $0.82 to $1.47/ton oflime. On anationwide basis, aggregating the model kiln costs apportioned among the affectedkiln populationprovides average costs as estimatedbyEPA.



### 3-37

### (



## ( Comment
CommenterIV-D-04 statedthatthe EIA is seriously flawed because it assumes lime producers canpass control costs throughto consumers. The commentermaintains that lime producers cannotraiseprices. The reasons include ahighly competitive market due to overcapacity, competitionfrom unregulated sources, competitive substitutes exist for mostkey markets, and significantmarketresistance. The commenter also claimedthatrecenthistory proves thatprices cannotbe increased. Finallythe commenter statedthatbecause the price increase assumed byEPA is erroneous, EPA's predictionthat onlytwo lime plants will close seriously understates the impact. One othercommenter (IV-D-12), also statedthatthey couldnot



### . . Increase pnces. Response
The fact thatmany limeplants are currently operating at less than full capacity implies thattheir supply curves shouldberelatively elastic (flat) atcurrentproduction levels because limeproducers canfairly easily change outputwithoutrunning into capacity constraints. Based on standard economic theory, underperfect competitionthe supply curve for each firm is equal to theirmarginal costcurve and eachproducer chooses to produce the quantity where theirmarginal costs are equal to the marketprice in orderto maximize theirprofits. The market supply curve is the sum ofthe supply curves ofthe individual firms and will reflectthe responsiveness ofthe individual firms to changes inprice. Assuming thatthe lime industry is very competitive (as argued by IV-D-04) and has substantial overcapacity implies thatthe industrymarginal cost curve (andthe market supply curve) should be relativelyflat atcurrentproduction levels. To the extentthatthe costs ofthe lime manufacturing MACT standard increase the marginal costs of lime production3

, having a very elastic (flat) supply curve is atextbookcase where the majority ofthe costs are passed onto consumers. A highly competitive market implies, by definition, that individual producers cannotunilaterally increase theirprices without losing most, ifnot all, of their customers. Itdoes not implythatthe marketprice will not increase in,responseto a general increase inthe costoflime productiondue to environ1T1entalregulations.
It is certainlytrue thatforeign lime suppliers (including suppliers located in Mexico) gain because this regulation applies onlyto domestic lime producers. The EIA assumed thatimport supplywas quite elastic (elasticity of7.0) and foreign suppliers are shownto increase theiroutput andtheirprofits inthe EIA. However, imports oflime accountfor an extremelytiny share ofthe lime marketpriorto the regulation (about 1 percentnationally) and even afairly large percentage increase inimports shows up as a very small change in absolute terms. The fact that imports accountfor such a small share ofthe

# u.s. lime market implies thattransportationcosts are too high for imported lime to be competitive inthe majority ofthe

# u.s. The barrierto imports

3A substantialportion ofthe cost associated with this rule is for kiln retrofits with capital equipment suchthat compliance capital expenditures may notvary greatly with output. However, maintenance costs and compliance capital depreciation are expectedto vary directly with output suchthatthe marginal costs ofproduction are increased.


### 3-38( causedbythese high transportation costs is expectedto prevent significantreplacementof domestic lime withimported lime.
CommenterIV-D-04 states that commercial lime producers wouldbe unable to raise prices for lime they sell to paperplants during times when the paperplants' captive lime facilities are off-linebecause the paperplants would simplymanufacture and store more lime attheirown facilities at much lowercost. It is possible thatthis wouldhappen to some extent, althoughpaper plants already have the optionto produce more lime captively. The fact thattheypurchase commercial lime currently suggests thatthey value the option ofbuying onthe spotmarket and may not substantially change theirinventorypractices unless there is a sufficientincrease in price. In addition, it is true thatcaptive lime kilns that are exempt from this MACT standard (e.g., kilns that are coveredby otherregulations, such as those inthe beet sugarindustry) could possiblybeginto operate during their current downtimes and sell lime into the commercial market. However, the fact thatthey do notcurrently find itworthwhile to do so again implies that the price increase would have to be large enough for themto significantly change their current operating procedures.



## ( To examine the historical supply responsiveness in the lime market, we estimatedthe supply elasticity for lime using datafrom 1983-2001. These estimates capture the overall change in the quantity oflime supplied inresponse to achange in the real (inflation-adjusted) price of lime, including any entry orexitofcaptive suppliers from the market. Based on estimates obtained from the econometric model, the domestic lime supply elasticitywas 1.24 atthe average price and quantity for theperiod and 0.98 using the lime price and quantity for 1997, the baseline year for the EIA. The value for the baseline year implies that a 1 percentincrease inprice would lead lime producers to increase theirlime productionby 0.98 percent, otherthings being equal.
Forthe lime price to remain constantdue to entry into the commercial marketby captive suppliers, that entrywould need to be sufficientthat it ledto the market supply curve being perfectly elastic. There is no evidence for aperfectly elastic market supply curve due to largescale entrybased·onhistorical estimates ofthe responsiveness oflime supplyto changes inreal pnce. There are substitutes for lime in many ofthe markets in which it competes, such as crushed limestone, caustic soda, soda ash, and otherproducts. However, unless the alternatives are perfect substitutes, this does not imply thatthe price oflime will not increase inresponse to an increase inproduction costs. The products have different attributes and differentprices and are clearly notperfect substitutes. In additionto estimating the overall responsiveness ofsupply, we also estimatedthe responsiveness ofthe quantity oflime demandedusing an econometric model and datafrom 1983-2001. Inthatmodel, an inflation-adjustedprice for alkalies and chlorine was used to representthe effect ofthe price oflime substitutes onthe quantity oflime demanded.4 The results showthatthe cross-price elasticity oflime withrespectto the alkalies

4Many alternative substitutes were used in alternative model specifications, butthe model with ( the alkalies and chlorine price was the preferred model based on model fit and consistencywith economic theory.

3-39

### (



## ( and chlorineprice is 0.30 for the baseline year. This suggests thata 1 percentincrease inthe alkalies and chlorine price wouldresult in a 0.30 percentincrease inthe quantity oflime demanded, implyingthatthese products are substitutes. However, they are notperfect substitutes. While itis expectedthatthere wouldbe some substitution ofalternative products for lime inresponse to ahigherlimeprice, it is highly unlikelythat otherproducts wouldbetreated as perfect substitutes for lime suchthatthe market lime price literally could not increase without all buyers substituting otherproducts. Assuming that lime is ahighly competitive market, economic theorytells us that individual limeproducers shouldnotbe able to unilaterally increase the price oftheir output without losing most, ifnot all, their customers. Ifafirm raises their selling price above the marketprice, theircustomers are expectedto shiftall oftheirbusiness to firms selling atthe marketprice. However, this does notimply thatthe marketprice for lime cannot increase inresponse to changes inproduction costs that shiftthe market supply curve.
To testthe responsiveness oflime demandto price, we estimatedthe demand elasticity for lime using an econometricmodel ofthe industry and datafrom 1983-2001. The results ofthe model suggestthatthe demand for lime is elastic, with an elasticity of-1.43 atthe averageprice and quantity overthe 1983-2001 period. Based on the price and quantity inthe baseline year, 1997, the elasticity for thatyearis calculatedto be -1.14. The value for the baseline yearmeans thatthe quantity oflime demanded would fall by 1.14percentinresponse to a 1 percentincrease inprice based onhistorical data. A claimthatthe lime price literally cannot increase due to high demandresponsiveness implies thatthe market demand curve is perfectly flatS (elasticity is equal to negative infinity), which is clearlynot supportedby empirical evidence. The fact that some firms are tied into longterm contracts at afixed price may delay increases inprice in some markets until the contracts expire, butprices are still expectedto increase following expirationof existing contracts.
The fact that lime prices have not increasedinrecentyears despite plant closures and increases inrealprices inno way implies thatthose events do not exertupwardpressure on prices. The relevant comparison is the price with and withoutthose events, notbefore and after they occur. Itis expectedthatprices wouldhave beeneven lowerifthere had notbeen closures and increases in inputprices.
As outlined inthe responses to these comments, there is no evidence to supportthe claim thatthe assumptionthat lime price will increase is erroneous, andthatthe estimatedeconomic impact ofthe rule is understated.
Comment

( sUnlike the marketdemand curve, the demand curve facing an individual firm in aperfectly competitive marketis expectedto be perfectly flat (demand elasticity ofnegative infinity).

3-40( Two commenters (IV-D-04, and IV-D-20) claimedthatthe EPA's sensitivity analysis does not adequately respond to the small business advocacy review (SBAR) Panel's recommendations. Response
In response to industry comments and to verify the reasonableness ofthe EIA results, market supply and demand elasticities were estimatedfor lime. The values from the preferred model for 1997 are very close to the primary elasticities usedinthe main text ofthe EIA and are well within the range ofelasticities used in the sensitivity analysis in Appendix B. In addition to the preferred model, numerous alternative models were estimated. As with any modeling exercise, there were some differences inresults across differentmodel specifications. However, the results were generally similar across specifications and there were no cases in which the estimated supply ordemand elasticity fell outside the ranges currentlyusedinthe Appendix B sensitivity analysis included in the EIA. Thus, the current analysis adequately responds to SBAR panel recommendations that a reasonable sensitivity analysis be employed and the empirical evidence is supportive ofthe current scenario presented in the Section4 ofthe EIA.
Comment 

## ( One commenter (IV

-D-04) statedthatthe EPA economic model for the lime market assumes anationally perfectly competitive market, but limeprices are primarily dictatedby large producers who sell capacityregardless ofprice. Response
This comment suggests thatlarge lime producers have marketpowerand therefore face a downward sloping demand curve andhave some abilityto setprices. Iflarge limeproducers do possess marketpower, then profit-maximizing behavior would implythat they would restrict outputbelow the levels expectedunderperfect competitionin orderto increase marketprice to the pointthattheirmarginal revenue is equal to theirmarginal cost. The largeproducers may have lowermarginal costs suchthatthe resulting price makes it difficultfor the smallproducers thattake the marketprice as givento remain inbusiness. However, the presence ofmarket powerin the lime industry would tend to increaseprices relative to the perfectly competitive case, not decrease them.
Comment
One commenter (IV-D-06) statedthey sell 40 to 50 percent oftheirlime to the soil stabilizationmarket, an areathathas encountered competitionfrom liquidpetroleumbyproducts. These low-cost, marginally effective products have made substantial progress entering this marketwith an inexpensive, unproven product and anyincrease in lime costs will reduce the competitiveness oflime in this market. ( Response



### 3-41

### (



## (

( An increase inthe price oflime relative to substitutes will tendto reduce the quantity of lime purchased. However, to the extentthatliquid petroleumbyproducts are marginallyeffective and unproven, they are presumablynot close substitutes for lime.
Comment
One commenter (IV-D-06) claims that although EPAhas indicated its rule will have largerimpacts on small businesses than large ones, the disparity is even greaterthan EPA estimates. The reductions inpre-tax earnings presented inthe EIA understate losses for small firms because the costs ofimplementation will be higherthan EPA estimates andthe price of lime will not increase. They also state thateven ifonly 2 to 3 ofthe 

### 14 small lime firms close, that would still be closure of

### 14% to 

### 21% ofthe small lime firms inthe domestic industry. This seems to be such a significant economic impactthatit should encourage the EPA to seriously consideradditional ways to minimize the impact on small businesses. Response
It is unclearwhatthe basis for the first part ofthis commentis (it seems the same claims they are making for small firms would also applyto large firms). As far as the secondpart, to the extentthat actual costs differfrom EPA estimates, itis possible thatthe actual losses experienced by firms wouldbe higheror lowerthanpresentedinthe EIA. However, the costs of implementationcurrentlyused for analysis reflectEPA's bestestimate ofactual costs. The assertionthatlime prices cannotincrease 

### in response to an increase inproduction costs is not credible (see comments above).
We also disagree thatthe number ofsmall firms atrisk ofclosure, 2 to 3, canbe considered a significantnumber inthe context ofSBAR. In any case, we have seriously considered ways to minimizethe impact on small businesses based on comments from industry and has substantiallyreduced the costs ofthis rule relative to pervious versions. As previously discussed, EPA, along withthe Small Business Administration and the Office ofManagement and Budget, convened apanel underthe authority ofSBARto talkwith small business representatives onhow to mitigatepotential impacts to small businesses associated withthe lime manufacturing NESHAP. This panel yielded areportthatincluded manyrecommendations on howpotential impacts to small businesses from theproposedrulel could be mitigated. These recommendations are also reflected inthe final rule.
Comment
One commenter (IV-D-06) claims thatthe EIA assumptionthatproduction costs will go down with decreases inproductionis wrong. The commenterclaimedthatthey maintains a close watch on costofproduction stated in costperton oflime produced. Simple economics dictates that an increase 

### in dollar costassociated with a decrease inproductionresults in ahigher costofproduction, which is ahighercostperton oflime. Response



### 3-42I 

### \



## (

( Presumably, the commenter's statementthatthere is an increase in dollarcostrefers to the compliance costs, butthose costs are shown separately from production costs in the EIA. The EIA does not saythat the total costperton oflime including compliance costs will decrease, it indicates thattotal production costs (not including compliance costs) will decrease inresponse to areduction in use ofvariable inputs as production falls.


### Comment
One commenter (IV-D-06) statedthey are alreadytrying to control costs while overthe past several years ourworkers' compensation insurance, group healthinsurance, natural gas, maintenanceparts, and liability insurance costs have continued to increase by double digit percentages, while sales prices have not increasedto this extreme. Trade and economic predictions indicate more similarincreases canbe expected. These factors shouldbe important considerations ofthe economic analysis. 

### Response
EPA gatheredbaseline datafor the lime industryto informthe economic analysis. Itis possible thatmarketconditions for the lime industryhave worsened overtime. However, the focus ofthe economic analysis is the incremental impacts ofthe lime manufacturing MACT standard, which mayberelatively small compared with otherchanges that are occurring within the lime industry. 

### 3.12 Risk Analysis Comment One commenter (IV-D-01) was concerned over EPA's use ofthe Acute Exposure Guideline Level (AEGL) in assessing the health risk associated with HCI. While not directly objecting to the conclusions reached by EPA, the commenter noted that the intended use ofthe AEGL, according to the National Research Council, is in conjunction with "once in a lifetime" exposures for emergency exposures ranging from 10 minutes to 8 hours. Because the AEGL values are intended to be used in conjunction with a single lifetime exposure, they can be higherthan short term limits recommended for populations with repeated exposures. It is not clear in the description ofthe NLA analysis, if NLA in their use ofAEGL was contemplating a once in a lifetime exposure Ofwhether exposures would be occurring repeatedly. The commenter stated that EPA should explicitly state how they believe AEGL values should be used in their risk assessment process and what are the possible exposure levels to the public. The commenterwas also troubled by the use in the rationale of both the RfC (estimated daily exposure that over a lifetime is not likely to result in significant non cancer effect in humans) and the AEGL (once in a lifetime exposure).



### 3-43

## (

( The commenter asked that EPA clarify their position on the use ofAEGL values for environmental risk assessments, and whether its use represents a "reasonable methodology" and "consistent with EPA methodology" as claimed in the preamble. Response This analysis evaluated only risks based on offsite exposure to the general population. EPA does not assess risks associated with occupational exposures, not do we have the authorityto address occupational issues.
In our evaluation ofthe NLA risk analysis, EPA reviewed the available acute dose-response values for this compound. Among these, the CalEPA reference exposure level (REL) and AEGL-1 values (2.1 and 2.7 mg/m3

, respectively) were found to be the most health-protective. Since these benchmarks were effectively the same, and AEGL values are products of a Federal effort in which EPA participates, we gave priority to the AEGL. Therefore, the AEGL-1 selected for analysis represented the most appropriate value. Although there are relatively protective acute dose-response assessment values for hydrochloric acid, protective assessments for other hazardous air pollutants may not exist. In such cases we may have to rely on less-conservative analyses, perhaps based on endpoints at mild effect levels. Nevertheless, EPA believes that the use of less-protective values (e.g., AEGL-2) is betterthan omitting acute exposure from the risk assessment. 

### 3.13 Applicability Comment One commenter (IV-D-03) requested that the rule be revised to exempt lime kilns operated in conjunction with public water treatment facilities. The commenterexplained that the kilns are used to recoverthe calcium carbonate sludge from theirwater softening process. The recovered lime is used on-site in the watertreatment process thereby reducing demand for these resources, avoiding the air emissions that would otherwise be associated with the transport ofthis material to a disposal site, and reducing the amount of solid waste generated. Underthe existing language ofthe rule, the lime recovery kilns located at the watertreatment plant would be subject to the rule because the treatment facility operates air stripping towers which are permitted to emit over 10 tons of a single HAP and over 25 tons peryear of multiple HAP. The commenter states that unlike lime kilns that process raw limestone materials, which contain metal HAP, the sludge from the water softening process, the only calcareous material fed to the kilns, does not contain metal HAP in any appreciable quantity. The elements and compounds found in the calcareous sludge from the water softening process are representative ofthose found in the treatment plants raw water source and the chemicals that are added as part ofthe water softening



### 3-44( process. As the public's water supply, neitherthe source water, sodium silicate, northe lime added priorto the kiln should have significant levels of metal HAP. The commenter also stated that EPA did not review lime kilns at watertreatment facilities in developing the proposed rule. Nor did the NLA include these lime kilns in their modeling of HCI emissions. The inclusion of lime kilns operated as part ofwater treatment facilities would be arbitrary and capricious and not based on any research or analysis. The commenter suggests EPA revise 63.7081(a) to include public water treatment plants in the list of lime producing facilities exempt from the rule. The commenter also suggests revising 63.7143 by modifying the definition of "Stone feed" by adding the following: "Stone feed does not include calcareous solids that are generated by and recovered in the water softening process at water treatment plants." 

### Response The lime recovery operation described by the commenterwas not the intended target ofthe rule. The EPA has revised the rule to exclude lime kilns that are operated as part of a publicly owned watertreatment facility to recover lime from water softening processes. 

### ( 3.14 General Comments Comment One commenter (IV-D-16) notes that in the proposal preamble, EPA asked for comments on a two-tiered approach for compliance monitoring. The commenter agrees that the rule should contain a threshold limit to initiate corrective action (which if corrected within a given time period would not constitute a violation). In many cases, entering a baghouse to perform maintenance on a broken bag poses a significant hazard to the maintenance personnel due to temperature, lack of oxygen, and high levels of sulfur oxides and nitrogen oxides. Thus the time period for corrective action must consider the critical time necessary to cool down and purge a compartment, so that the dangerto maintenance personnel can be minimized. 

### Response
For baghouses monitored using BLD systems and for ESP monitored using PM CEM, alarm systems may be used to alert operators when preset levels have been have been exceeded indicating that corrective actions may be necessary. Only after the alarm time has exceeded 5 percent ofthe total operating time in a 6-month period has a violation of an operating limit occurred. Alarm time is counted by how long it takes it takes from the onset of a BLD or PM CEM alarm to the time that corrective 

## <: action is initiated. By not counting the time required to correct the problem, the plant owner or operator can take the time necessary to address the cause ofthe alarm in a


### 3-45

## (



## (

( safe and efficient mannerwithout incurring additional alarm time. Procedures to be followed in inspecting control devices for the cause of alarms or malfunctions should be incorporated into a facility's OM&M plan and SSM plan.
For other parametric compliance monitoring options, the rule requires that the owner/operator define the compliance parameters to be monitored in their OM&M plan.

During the initial performance tests, they are required to monitor and establish the value or range ofthe parameters. EPA believes that the initial performance tests will be designed to give the owner or operatorflexibility in adhering to the established range for monitored parameters. These values must be reported in the results ofthe test and notification of compliance status to the permitting authority and must be approved by the permitting authority. During subsequent operations, ifthe monitored parameters exceed the values orfall outside the range determined during the initial performance test, it is a violation ofthe operating requirements of the standard (unless it is the result of a malfunction to which the facility responds to in accordance with the SSM plan). The EPA has no basis for allowing deviations before considering the facility to be in violation. The owner/operator has ample opportunity to establish a range for the operating parameters and must thereafter operate within that range. Comment Several commenters (IV-D-04, IV-D-05, and IV-D-08) believe the rule should not require HCI testing of all kilns. Commenter IV-D-04 believes the rule should provide state agencies with the discretion to not require HCI testing of all kilns. Commenters IV0-05 Western and IV-D-08 Engineering believe the rule itself should allow flexibility in HCI testing. The commenters note that in recent years, many lime plants have been forced to idle or infrequently operate kilns at operating plants due to increased fuel cost, reduced customer demand, etc., and start up ofevery kiln for the purpose ofconducting HCI testing would require significant expenditures. Commenter IV-D-04 notes that this would also result in PM and other emissions that otherwise would not be generated. Commenter IV-D-04 uses the example of an idled kiln ofthe same type as an active kiln at the plant, fired with the same fuel and stone; it may be reasonable for a state agency to conclude that HCI emissions testing from the active kiln can be used to estimate emissions from the idled kiln. Furthermore, the commenters note that testing may not be warranted on kilns that represent small fractions ofthe plant's total capacity. As a result, Commenter IV-D-04 requests that the rule be revised to provide state agencies with the discretion to determine whethertesting of all kilns at a lime plant is necessary in order to demonstrate that a plant is an area source. Commenter IV-D-05 requests that the rule state that plants which desire to claim area source status be required to test a sufficient number of kilns so that 70 percent or more ofthe potential production capacity of the plant is tested for HCI. Or, as an alternative, EPA could allow HCI test results from one kiln to be extrapolated to estimate emissions from comparable kilns at the same plant.



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### ( Response
A lime manufacturing plant's status as an area source or a major source is not addressed by this rule. Ifthere are questions regarding whether a source is an area source or a major source, the owner or operator should referto the General Provisions, in particular, section 63.2, and contact the appropriate permitting authority if additional clarification is needed. We believe this is the best approach for major source determinations because every site may have different issues, and attempting to address these site specific issues in this rule would be inappropriate. We believe allowing the permitting authority to evaluate these issues on a case-by-case basis is the best approach. 

### Comment
Several commenters (IV-D-04, IV-D-17, IV-D-11, and IV-D-13) state that the rule should allow lime plants to use the following emission factors to estimate HAP metal emissions: 0.15 percent of PM emissions from kiln stacks and 0.07 percent from stone handling operations. Commenters IV-D-04 and IV-D-17 believe that the quantity of metal HAP emitted from lime plants is sufficiently low that it is highly unlikely that such metals will be present in quantities that would have any effect on whether a commercial lime plant exceeds the 25 ton per year major source threshold for all HAP. According to commenter IV-D-04, Docket Item No. 11-8-43 establishes the HAP metal content of lime ( kiln emissions to be 0.15 percent, and Docket Item No. 11-8-77 establishes the HAP metal content offugitive stone emissions to be 0.07 percent. Commenter IV-D-16 Refractories also commented that the rule should allow for the use of emissions factors for HAP metals. Commenter IV-D-04 notes that the cement MACT allows cement plants to assume that HAP metals emissions constitute 1 percent of PM emissions for the purpose of area source determinations. This commenter believes the quantities of metal HAP from lime plants are so small they will not affect the area/major source determination, and thus measurement ofthe metal emissions is unnecessary. 

### Response
The rule, as proposed, contained no requirement to measure HAP metals in the emissions from kilns or stone handling operations and we see no reason to add such provisions. The final rule does not require that lime manufacturing plants perform emissions testing for HAP metals. Therefore, we see no reason to establish a specific ratio in the rule. However, nothing in the rule would preclude these ratios from being used. 

### Comment ( Several commenters (IV-D-04, IV-D-16, IV-D-11, and IV-D-13) comment that testing for HAP organics should not be required because it is highly unlikelythat such


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( compounds will be present in quantities that would have any effect on whether a commercial lime plant exceeds the 25 ton peryear major source threshold for all HAP. Commenter IV-D-04 notes that lime kilns are not expected to emit significant quantities of organic HAP because inorganic limestone is the only feed material processed, and EPA's testing of 10 commercial lime kilns detected virtually no organic HAP (Docket Item No. 11-8-121). This commenter also notes that lime kilns at sugar beet facilities have been exempted from the lime MACT, and no analysis of organic emissions from lime kilns at sugar beet facilities has been conducted (Docket Item Nos. 11-8-44 and 81). 

### Response
EPA agrees with the commenters, the rule does not require that emission testing for HAP organics be conducted. 

### Comment
One commenter (IV-D-04) states the requirement in 

### § 63.7142(b) to use FTIR, Method 18 orASTM D6420-99 if organics testing is conducted for area source determinations should be deleted. The commenter notes that the proposed requirement creates the inference that organics testing should be conducted, and that testing beyond the 36 volatile organics specified in the ASTM method is necessary, when the chance that organics will cause lime plants to be a major source is highly remote. 

### Response
As stated in the previous response, the final rule does not require emission testing for HAP organics. However, we do not believe it is appropriate to specifically state that organicstesting is not required. It is possible that a permitting authority may wish to have a facility perform organic HAP testing due to site specific considerations. Ifthis occurs, we believe that EPA-approved test methods should be used. 

### Comment
One commenter (IV-D-02) believes the final rule should include an alternative limit based on the quantity of HAP metals released. Forexample, "a lime manufacturing plant with a dry collector and a particulate release greaterthan 0.12 Ib/tsfshould not be required to meet a MACT surrogate particulate value when its release of HAP metals is equal to or less than that of EPA's basis for establishing the 0.12 1b PM/tsf limit...a lime plant that has a stone feed stock low in heavy metals and/or fires with natural gas can have a lower HAP metals release than a plant meeting the proposed MACT particulate limit. Since the intent ofthe proposed regulation is to control the release of HAP metals, whether a company complies via operating practices or particulate control equipment should be irrelevant." In the case ofwet scrubbers, the commenter recommends an alternative HAP limit of 1.5 Ibs/1000 tons of stone feed


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## ( (based on a particulate release of 1.0 Ib/tsf and a HAP metals concentration of 1,500 ppm in the particulate). 

### Response
We do not have, and the commenter did not provide, sufficient HAP metal emission information on which to establish a metal HAP emission limit as an alternative to the PM emission limit. We commonly use PM emissions as a surrogate for metal HAP emissions, finding that controlling PM emissions will control the non-volatile and semi-volatile metal HAP. At-the-stack controls used at lime manufacturing plants, i.e., baghouses, ESPs, and wet scrubbers, capture non-volatile and semi-volatile metal HAP non-preferentially along with other PM, making PM a permissible indicatorfor HAP metals. We believe using PM as a surrogate is preferred by most sources as the cost of emissions testing and monitoring that would be required to demonstrate compliance with the otherwise numerous standards that would apply to individual HAP metals would be much higherthan testing for and monitoring for PM emissions. 

### Comment
Several commenters (IV-D-04, IV-D-16, IV-D-11, and IV-D-13) state that performance testing should be conducted under "representative" conditions ratherthan underthe "highest production level reasonably expected to occur." Commenter IV-D-11 notes that there are inconsistencies between what is proposed in Table 4 ofthe rule and what is required underthe General Provisions at 40CFR 63.7(e)(1). EPA has recently amended the Cement MACT to fix similar inconsistencies, and the commenter suggests the Lime MACT be similarly revised. 

### Response**y~** We have changed the requirement in the final rule to require testing under representative conditions, which is in agreement with the language in the General Provisions. 

### Comment
One commenter (IV-D-04) notes that reports should be required only for malfunctions, not startups and shutdowns. The commenter states that in recent proposed amendments to the General Provisions in Subpart A of Part 63, EPA has determined that requiring reporting of startups and shutdowns is "unnecessary and burdensome" (67 Fed. Reg. 72,881). 

### Response Section 63.7121(b) requires that deviations from operating, VE, and opacity limits, including periods of startup, shutdown, or malfunction be reported. EPA intends for this requirement to be consistent with the General Provisions and has revised this


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## (

( paragraph to clarify that reports of startups, shutdowns, and malfunctions are to be made in accordance with section 63.10(d) ofthe General Provisions. Comment
Two commenters (IV-D-04 and IV-D-16) believe the final rule should provide a risk-based exemption from the entire rule (notjust from HCI standards) for plants at which modeled risks are below health based thresholds. Commenter IV-D-04 notes that EPA recently solicited comment on providing risk-based exemptions in proposed MACT standards for several sources categories. This commenter strongly supports the view that such exemptions should be provided in MACT standards that impose substantial costs while achieving negligible reductions in risks to public health, and believes the lime MACT fits this description. Response Otherthan the decision to not regulate emissions of HCI from lime manufacturing, EPA did not consider and did not request comments on providing riskbased exemptions for lime manufacturing facilities. Although EPA is aware that riskbased exemptions were being discussed in other proposed rules, no decisions have been made by the Agency regarding risk-based exemptions and application to industry groups or individual plants. Due to the uncertainty of how these exemptions would be structured, we do not believe that it would be appropriate to include these site specific risk based exemptions in the final rule. We also believe that including such a substantive change in the final rule without allowing the general public an opportunity to comment would be a violation ofthe Administrative Procedures Act, especially in light of the fact that their inclusion in other proposed rules have generated significant negative comment from the public. Comment One commenter (IV-D-04) states the Benefits Analysis is based on inaccurate assumptions, and presents conclusions regarding reductions in metal HAP that are greatly overstated.
The commenter submitted comments to the Small Business Advocacy Review (SBAR) Panel explaining that the emission factor for uncontrolled existing kilns is 27 times smallerthan the emission factor used by EPA to calculate baseline emissions. The commenter notes that its emission factor is based on actual test data from these kilns. The commenter also notes that the emission factorfor existing uncontrolled stone handling operations is also overstated; it was derived using AP-42 emission factors with liE" ratings. The commenter states that it also presented to the SBAR Panel a more reliable emission factor for these units that is rated "C" and was revised in 1995.


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## ( In addition, the commenter claims that EPA overstated the amount of new capacity and the emissions from new rotary kilns. The commenter states, "EPA should either reflect (our) estimates in the preamble to the final rule, or provide a reasoned response to our comments that EPA's estimates are overstated

...we believe the best estimate of metal HAP reductions is 3.5 tons (7,000 pounds) per year. Based on the 56 lime plants predicted to be subject to the MACT rule, this translates into an annual reduction in metal HAP per lime plant of 124 pounds. 

### Response
EPA reviewed the new information on PM emissions presented by the commenter as well as their calculations of baseline emissions and emission reductions resulting from the rule and finds them to be reasonable. The preamble to the final rule reflects these revised estimates. However, even with these revised estimates, we still note that the estimated benefits are still significantly higherthan the costs for the final rule. 

### Comment
One commenter (IV-D-22) states that EPA should clarify that PM from nuisance dust collectors that service coolers are not included in the collective PM limit for kilns/coolers. The commenter notes that nuisance dust collectors, commonly associated with coolers, (called the cooler duct collector in some plants) collect dust generated in the transfer from the cooler to the material handling system, and PM from the nuisance dust collector should not be included in the kiln PM limit, but instead should be exempt as part ofthe lime handling system. 

### Response
The standard only applies to air used for cooling that is exhausted from the cooler to the kiln or that is exhausted separately to the atmosphere. Operations that process only lime product, lime kiln dust, orfuel are excluded from coverage. The rule was revised to clarify that dust emitted in the transfer from the cooler to the material handling system is not included in the calculation of the PM emission rate. 

### Comment One commenter ( Docket No. OAR-2002-0052, item 530) states that clean air is essential, and requests that the companies that pollute the air be made to clean it up. 

### Response
EPA acknowledges the comment and believes this and other standards \ promulgated underthe CAA are effective at reducing HAP emissions.



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## ( Comment One commenter (IV-D-15) requests that EPA withdrawthe proposed Lime manufacturing NESHAP and publish a new draft that is substantially more environmentally protective of PM1 

### O. Response
The degree to which emissions of any substance can be reduced by regulation are a reflection ofthe statutory basis ofthose regulations. Under section 112 ofthe CAA, EPA is directed to establish MACT standards which are based on the emission reduction being achieved by the top performing, currently operating facilities. The standard for lime manufacturing plants used this approach and we believe that the result ofthe standard will be a substantial reduction in total PM emissions (over 3,880 tons per year), including PM10 emissions.



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