11011 C ODY O VERLAND P ARK

, KS 66210

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CURTIS D

. LESSLIE

, PE

D IRECTOR OF E NVIRONMENTAL A FFAIRS WRITER ’ S DIRECT LINE

– 913/319-6065

September 4, 2009

BY ELECTRONIC SUBMISSION

Mr. Keith Barnett

U.S. EPA Docket Center

Air and Radiation Docket

Mail Code 6102T 1200 Pennsylvania Ave., N.W. Washington, DC 20460

Re: Comments on Proposed Portland Cement NESHAP Docket ID No. EPA-HQ-OAR-2002-0051

Dear Mr. Barnett:

Ash Grove Cement Company (“Ash Grove”) is writing to offer comments on the May 6, 2009 proposed revisions to the National Emission St andards for Hazardous Air Pollutants for the Portland Cement Manufacturing Industry (“S ubpart LLL” or “PC NESHAP”). 74 Fed. Reg 21135 (May 6, 2009) (the “Preamble”). Ash Grove supports the comments being submitted by the Portland Cement Association (“PCA”) and, to the maximum extent that those comments are consistent with those stated here, adopts t hose comments as Ash Grove’s own. However, Ash Grove is uniquely positioned on certain issues an d so finds it necessary to write comments in supplement to those submitted under PCA letterhead. Ash Grove has organized its comments to

match the order in which issues were presented in the preamble.

I. Background

Ash Grove is an American owned business headqu artered in Overland Par k, Kansas. Ash Grove is the fifth largest cement manufacturer in the Un ited States with cement plants in nine states across the country. A pioneer of the limestone and cement industries, the Company was incorporated in Missouri in 1882 and has been ma jority owned and controlled by the Sunderland family since 1913. The nine cement plants opera ting in the Ash Grove system are some of the

most efficient and best maintained in the count ry and have an annual production capacity of more than 8.0 million tons of cement. The qua lity portland and masonry cements produced at these plants are used in the construction of highways, bridges, commercial and industrial complexes, residential homes, a nd a myriad of other structures.Keith Barnett September 4, 2009 Page 2

II. Proposed Mercury Standard

Ash Grove respectfully comments on two aspects of the mercury standard. First, Ash Grove has concerns regarding how the mercury standard was established for the one category that EPA proposed. Second, Ash Grove is strongly supportiv e of the establishment of two subcategories for purposes of establishing the me rcury standard, one for the affect ed sources with low levels of mercury in their limestone (<225 ppb, as charged) and one for the affected sources with elevated levels of mercury in their limestone ( ≥ 225 ppb, as charged). Our specific comments and

concerns are outlined below.

A. Variability in Establ ishing Existing Source Floor

Ash Grove believes that the existing source floor was not appropriately established. The floor was based on an extremely limited data set cons isting of raw materials data for a 30 day period. Ash Grove has been studying the mercury emissions at its Durkee, Oregon kiln since 2006; these

data are included as Table 1 below. 1 Between June 2007 and April 2009, the plant collected monthly composite samples of the limestone for mo st of the months the plant was operating and analyzed them for mercury. These monthly averages ranged from 424 ppb to 1,740 ppb. All limestone originated from the on-site quarry.

Table 1. Durkee Limestone Mercury Data Summary 2007-2009

Blast # Date Bench (toe elev.) Tonnage Month ppm

2007-7 6/13/2007 3805 38,324

2007-8 6/27/2007 3805 34,313 July 1.02

2007-9 7/18/2007 3805 47,237

2007-10 8/1/2007 3400 37,433

2007-11 8/15/2007 3715 36,690 September 1.15

1 Ash Grove’s Durkee plant is an area source that voluntarily entered into an enforceable order requiring the installation of mercury controls that will redefi ne the state of the art for cement kilns. These controls must be operational by mid-2010 or Ash Grove will face daily stipulated penalties. Approximately 99 percent of the mercury emitted by the Durkee plant derives from materials quarried on site. Through use of the controls Ash Grove committed to achieve at least a 75 percent SRE and to take all reasonable measures to achieve an 85 percent SRE. Notwithstanding an initial invest ment of more than $18 to $2 0 million in the controls and substantial annual operating expense, the Durkee plant will not be ab le to comply with a mercury emission standard equal to the aver age emission rate of the 12 percent of the cement plants with the lowest mercury containing limestone.Keith Barnett September 4, 2009 Page 3

2007-12 8/19/2007 3805 38,138

2007-13 9/12/2007 3355 41,518

2007-14 9/26/2007 3805 40,407 October 1.07

2007-15 10/3/2007 3355 18,506

2007-16 10/10/2007 3805 24,138

2007-17 11/1/2007 3805 10,695

2007-18 12/18/2007 3580 49,725 December 0.888

np 2/6/2008 3805 14,577

2008-3 2/20/2008 3445 33,794

2008-4 2/27/2008 3445 28,000 March/April 1.74

2008-5 3/6/2008 3445 20,276

2008-6 3/26/2008 3400 38,621

2008-7 4/9/2008 3400 39,587 May 1.09

2008-8 5/21/2008 3355 44,028 June 1.39

2008-9 6/4/2008 3355 17,380

2008-10 6/29/2008 3760 36,417 July 0.706

2008-11 8/13/2008 3760 37,913

2008-12 9/11/2008 3760 38,138

2008-13 10/22/2008 3760 34,000 October 1.03

2008-14 11/12/2008 3760 38,138

2008-15 11/26/2008 3760 41,421

2008-16 12/17/2008 3760 46,201 December 1.3

2009-1 1/15/2009 3760 36,914

2009-2 1/28/2009 3760 48,856 February 0.735

2009-3 2/5/2009 3760 29,738

2009-4 2/18/2009 3760 42,483

2009-5 2/25/2009 3760 15,448 March 1.04

2000-6 3/11/2009 3760 48,325

2009-7 3/18/2009 3715 43,545 April 0.483

2009-8 4/1/2009 3760 48,325

2009-9 4/9/2009 3760 43,449

2009-10 4/22/2009 3760 41,518 May 0.424Keith Barnett September 4, 2009 Page 4

This range of values demonstrates the tremendous variability that occurs month to month within the same quarry (see, also, Figure 2 below). Th is same variability must be accounted for in establishing the floor. For example, the proposed existing source floor re cognized a variability factor of only 57 percent. However, in the Durkee data the variability was considerably higher. If the floor value using the 11 kilns identified in Table 1 were calculated using the variability seen in the Durkee quarry and three standard deviat ions are applied to the average, then the floor

would be 34 lb/MM ton feed ra ther than 26 lb/MM ton feed. As the D.C. Circuit explained in the Medical Waste Incinerator (MWI) NESHAP d ecision, for an emissions limit to be achieved in practice, it must be achievable under the worst foreseeable circumstances. Sierra Club v.

EPA , 167 F.3d 658 (D.C. Cir. 1999). In the CKRC II decision, the D.C. Circuit noted that the performance of non-floor sources can be indicativ e of what variability the floor sources might experience. The Durkee plant may or may not be a floor source. However, there is no reason to believe that the variability that the Durkee quarry e xperiences in its limestone is not indicative of the variability experienced at all quarries. Merc ury can vary considerably over a single mineral formation (as demonstrated in Figures 2 and 3 belo w) and this variability must be accounted for in setting the floor. The length of time repr esented by the Durkee quarry data make it ideally

suited for use in establis hing floor variability.

Ash Grove believes that EPA has not adequately accounted for variability in establishing the mercury floors. The PCA comments provide exte nsive detail regarding the need to account for actual variability in establishing the floor and we do not reproduce those data or arguments here. However, Ash Grove adopts by reference those argum ents to the maximum extent that they are

consistent with the remainder of this letter. We urge EPA to revise the new and existing source floors to properly account for variability.

B. Choice of Sources in Floor

Ash Grove has considerable concern over the sources that were chosen for establishing the floor. Section 112(d)(3) states that the new source st andards “shall not be less stringent than the emission control that is achieved in practice by the best controlled simila r source.” For existing sources the Act similarly states that it must be a source representative of that category or subcategory. Notwithstanding the requirement that a floor source mu st be representative of the sources in the category or subcategory, The source that is identified as the lowest emitting source (source 1233 in Table 1), is not representative of the predominant product type manufactured by that kiln. Kiln 1233 was manufacturing oil well cement during the time that mercury data were gathered and so the data are not representative of typical operation of that kiln or any other kiln in the category as oil well cement is only a small fraction of the cement manufactured in the industry. While the oil well cement was within th e range of products manufactured in this kiln, we understand that it only represen ts less than 20 per cent of the total pr oduction on an annual

basis. A second kiln with the same confi guration at the same plant (source 1560) emitted approximately seven times more mercury than source 1233 during the same time period while making the primary product of the plant (Type I/II cl inker). In addition, four of the eleven kilns identified as part of the floor (1302, 1315, 1286 a nd 1364) are older wet kiln s that are currentlyKeith Barnett September 4, 2009 Page 5

not operating and so should not be considered part of the floor as they are no longer part of the best performing 12 percent of sources. While Ash Grove cannot comment on the likelihood of restarting for the two kilns in this group that it does not own, Ash Grove can say that the likelihood of restarting the two kilns it does ow n is low given the current economic downturn

and that the kilns are old wet k ilns located at a plant that ha s been in operation since 1929. Given this situation, we believe that there is no longer any basi s to consider these kilns as operational, “similar sources” or actually achi eving any emission rate—all prerequisites to considering them part of the floor.

EPA should revise the standard to exclude data from source 1233 to the extent that it was not representative of industry operati ons. Alternatively, the variability analysis must include the full range of variability associated with kiln 1233 ma nufacturing Type I/II cement (as exemplified by the collocated kiln 1560). Similarly EP A should remove sources 1302, 1315, 1286 and 1364 from the floor as they are no longer pa rt of any category or subcategory.

C. Subcategorization Based on Limestone Mercury Content

Ash Grove believes that the final rule should include a separate subcategory based on the mercury content of the limestone in an affected source’s quarry. In the preamble, EPA expressly

solicited comments on whether it is appropriate to subcategorize for purposes of the mercury

standard. Ash Grove sees several bases for subcat egorization, including diffe rences in kiln type and need to waste CKD. However, the most im portant subcategory to establish relates to the mercury content of the on-site limestone that is in troduced into the kiln. In developing the rule, EPA considered the quarries collocated with cement kilns as a part of the affected source. This has manifested itself in the way that the limits were developed, with the best performing source being inextricably linked to the mercury content of the collocated quarry. Every kiln in the floor had limestone mercury concentration of less than 25 ppb. In this regard, the attributes of the quarry define the nature of the a ffected source every bit as much as the type of fuel defines the nature of a boiler. Just as EPA subcategorized based on the fuel attribut es when it published its Boiler NESHAP, EPA should similarly subcategori ze when it promulgates the Portland Cement

NESHAP. The nature and desi gn considerations of the fac ility are determined by the

characteristics of the on-site limestone and ot her raw materials and t hus justify a separate subcategory.

1. EPA Precedent for Establishing Subcategories

Both the Clean Air Act and the courts clearl y recognize EPA’s treme ndous discretion in establishing NESHAP subcategorie s. Section 112(d)(1) of the Cl ean Air Act states that “The Administrator may distinguish among classes, type s, and sizes of sources within a category or subcategory in establishing such standards...” Ther efore, there is clearly authority under the Act for establishment of subcategories. This author ity is not specifically limited by the Act, thus leaving the agency substantial discretion in how it establishes subcategories and the appropriate criteria for subcategorizing source categorie s include “technology, pr ocess, product, andKeith Barnett September 4, 2009 Page 6

emissions characteristics.” Natural Resources Defense Coun cil v. Envtl. Prot. Agency , 489 F.3d 1364, 1372 (D.C. Cir. 2007) ( PCWP MACT) ; see also 67 Fed. Reg. 78045, 78058 (Dec. 20, 2002) (subcategorization typically reflects “differences in manufacturing process, emission characteristics, or techni cal feasibility...”).

On multiple occasions over the past decade, EPA has discussed the appropriate bases for establishing subcategories. A le ngthy discussion of the appropri ate basis for subcategorization can be found in the preamble to the Seconda ry Aluminum Production NESHAP. There EPA

stated:

“Subcategorization within a source category may be considered when there is enough evidence to dem onstrate clearly that there are significant differences am ong the subcategories. The criteria to consider include process operations (including differences between batch and continuous operations), em ission characteristics, control device applicability, safety, a nd opportunities for pollution prevention

.

“The EPA examined the processes, the process operations, and other factors to determine if separate cl asses of units, operations, or other

criteria have an effect on air emi ssions from emission sources, or the controllability of those emissions. Based on differences in emissions, the type of materials processed and the fluxing practices employed, the EPA has distinguished two specific classes of melting, holding, and refining furnaces. Because HAP emission potential is strongly in fluenced by the contaminants present in the materials that are melted and the type and amount of flux added, these furnaces would be subject to sepa rate standards under the proposed rule.” 64 Fed. Reg. 6960 (Feb. 11, 1999) (emphasis added).

Thus, as far back as 1999 EPA was recognizing thatthe constituents in th e raw materials form a reasonable basis for subcategorization where the air emissions are affected by those constituents.

EPA took a similar position in the 2000 proposal for the Generic MACT rule. In that case EPA once again noted that multiple different character istics, including the ability (or inability) to avoid a particular HAP (i.e., pollu tion prevention), are identified:

“Section 112(d)(1) of the CAA give s us the authority to ‘‘* * * distinguish among classes, types, and sizes of sources within a category * * *’’ when developing standards. Subcategories, or subsets of similar emission sources within a source category, may be defined if technical differences in emissions characteristics, processes, c ontrol device applicability, orKeith Barnett September 4, 2009 Page 7

opportunities for pollution prevention exist within the source category (57 FR 31576). Specific examples of these differences

include the types of products, process equipment differences, the type and level of emission controls, emissions sources, and any other factors that woul d impact a MACT standard .” 65 Fed. Reg. 76413 (Dec. 6, 2000) (emphasis added).

This passage indicates a clear ag ency understanding of the breadth of characteristics that can be

taken into account in es tablishing a subcategory.

Consideration of differences in emission charac teristics was also identified as a basis for subcategorization in the Primary Coppe r Smelting NESHAP. There EPA stated:

“Section 112 of the CAA provides th e Administrator the discretion to divide categories of sources into subcategories where appropriate. In establishing such source categories for other source categories in the NESHAP program, we have considered fact ors such as differences in process operations (including differences between batch and continuous operation), emission characteristics, control device applicability, and opportuniti es for pollution prevention .” Primary Copper Smelting NESHAP Background Information Document at 2-6 (2001) (emphasis added).

The consideration of emission char acteristics and the constituents in the raw materials are quite distinct from the subcategorization criteria that have been previously cr iticized by the courts as well as by environmental groups. In the Plywood and Composite Wood Product (“PCWP”)

NESHAP the Sierra Club critici zed EPA for subcategorizing based on cost or based on risk. As EPA stated in that rule’s preamble,

“The commenter stated that subcat egories based solely on risk do not bear a reasonable relationship to Congress’ technology based approach or the statutory structure and purpos es of CAA section 112, and are not authorized by the CAA.

“According to the commenter, cat egories and subcategories are required to be consistent with the categories of stationary sources in

CAA section 111. The commenter was not aware of any instance in which EPA has established categorie s or subcategories based on risk.

The commenter stated that EPA ro utinely defines subcategories based on equipment characteristics ( e.g. , technical differences in emissions characteristics, processes, control device applicability, or opportunities for P2). According to the commenter, EPA has notKeith Barnett September 4, 2009 Page 8

offered any explanation for why re interpreting the statute to ignore nearly 12 years of settled practices and expectations under the MACT program is reasonable, nor why re ducing the appli cability of HAP emission standards serves Congress’ s goals in enacting the 1990 CAA Amendments.” 69 Fed. Reg. 45987 (July 30, 2004) (emphasis added).

In this response to comment, EPA outlined the po sition of the environmental groups, namely that subcategorization cannot be based on risk. However, EPA also made clear that the environmental group’s belief that differences in emissions characteristic s, processes, control device applicability, and opportunities for polluti on prevention are well established bases for subcategorization. In evaluating the PCWP rule, the D.C. Circuit specified that subcategories are a step in the path towards establishing em ission standards and recognized EPA’s “broad subcategorization authority.” NRDC v. EPA , 489 F.3d 1364,1372 (D.C. Cir. 2007). The court

held in that case that EPA coul d not establish a subcategory “whos e defining characteristic is that its members will never be subject to emission standards.” Id . However, the court never questioned the broad discretion EPA has to creat e subcategories where th e subcategory members are appropriately evaluated and made subject to emissions standards.

In the Fabric Coating NESHAP, EPA again out lined its basis for subcategorization.

“The statute gives us discreti on to determine if and how to subcategorize. *** A subcategory is a group of similar sources within a given source category. As part of the regulatory development process, we evaluate the similariti es and differences between industry segments or groups of affected s ources comprising a source category. In establishing subcategories, we consider factors such as process operations (type of process, raw materials, chemistry/formulation data, associated equipment, and final products); emission characteristics (amount and type of HAP); add-on control device applicability; and opportuniti es for pollution prevention. We may also consider existing rules or guidance from States and other regulatory agencies in determin ing subcategories.” 67 Fed. Reg. 46039 (July 11, 2002) (emphasis added).

In addition to emissions characteristics, proces ses, control device applic ability, and opportunities for pollution prevention, EPA has also consid ered scale of emissions as a basis for subcategorization; EPA has de fined subcategories based on th e tonnage of emissions. For example, in the Reinforced Plastic Composite s (“RPC”) NESHAP EPA defined two different new source subcategories based on the level of HAP emissions from the source.

“We developed subcategories based on size ( i.e., tpy of HAP emitted) in defining the new source MACT floors. These subcategories are sources that emit 100 tpy or more from open molding, pultrusion,Keith Barnett September 4, 2009 Page 9

centrifugal casting, continuous lamination/casting, SMC and BMC manufacturing, and mixing operations; and all other new sources.” 68 Fed. Reg. 19377 (April 21, 2003).

EPA explained magnitude of emissions as a basis for subcategorization as follows:

“In developing the floor for ne w sources, we developed two subcategories--sources with em issions of 100 tpy or above and sources with emissions below 100 tpy. Our reason for examining sources with emissions below 100 tpy separately is that such facilities are likely to have more difficulty maintaining and operating add-on controls than larger-emitting sources, and we are unsure of the performance of add-on controls at these

facilities . Separating the data into large and small HAP-emitting sources for developing new source MA CT floors was also one of the recommendations of the SBAR Panel.” 66 Fed. Reg. 40324 (Aug 2, 2001) (emphasis added).

In that same NESHAP EPA also subcategorized for existing sources ba sed on other criteria:

“However, we did segregate exis ting sources by resin application technique, resin type, and final products, and developed separate floors for each process/product grouping.” Id.

Thus, in the RPC NESHAP, EPA concluded that it was appropriate to subcategorize based on magnitude of HAP emissions and the nature of th e raw material inputs, am ong other things. Part of the consideration for subcategorization based on magnitude of emissions was the difference in ability to control betwee n the two subcategories.

The recognition of EPA’s broad authority to subcategorize and the appropriateness of subcategorization based on raw mate rial attributes is not limited to EPA. In its comments on the Boiler NESHAP, the Natural Resources Defe nse Council (“NRDC”) made the following

comments:

“EPA has previously interpreted th e statutory term “category” to mean equipment that shares physical char acteristics relevant to the degree of pollution control that can be achieve d. The Agency likewise has stated that subcategories should be defined by considering ‘process operations (types of process, raw materials, chemistry/formulation data, associated equipment a nd final products); emissions characteristics (amount and type of HAPs); add-on control device applicability; and opport unities for pollution prevention.’ The EPAKeith Barnett September 4, 2009 Page 10

recognized the importance of differences based on the type of products and processes when it stated:

Subcategories, or subsets of similar emission sources within a source category, may be defined if technical differences in emissions characteristics, processes, control device applicability, or opportunities for pollution prevention exist within the source category. Specific examples of these differences include the types of products, process equipmen t differences, the type and level of emission controls, emissions sources, and any

other factors that would impact a MACT standard.

Indeed, an earlier agency proposal r eaffirmed EPA’s interpretation that its subcategorization au thority is limited to relevant physical and operational characteristics of the eq uipment in question, not the health effects of the pollution it emits. EPA’s interpretation is eminently reasonable, and is entitled to judicial deference. By contrast, if EPA chooses to reverse itself and begin to subcategorize based on risk, it faces an uphill climb; such changes in interpretation are “entitled to considerably less deference than a consistently held agency view.” EPA has not offered any explanati on as to why re interpreting the statute to ignore nearly 12 years of settled practices and expectations under the MACT program is reas onable, nor why reducing the applicability of HAP emission sta ndards serves Congress’s goals in enacting the 1990 CAAA.” NRDC Comments on Boiler NESHAP; Docket ID No. EPA-HQ-OAR-200 2-0058 at 20-21 (March 14, 2003) (emphasis added in NRDC letter; citations and footnotes omitted).

Thus, NRDC itself has recognized that ther e are multiple different bases for creating subcategories including technical differences in emissions characteristics, processes, control device applicability, or opportuni ties for pollution prevention exis t within the source category. These include multiple different possible charac teristics under the classification of “process,” including differences in raw materials and chemis try/formulation data. NRDC’s statement that these bases for subcategorization are “eminently r easonable” and “entitled to judicial deference” are every bit as notable as NRDC’s demand that EPA not “ignore 12 years of settled practices,” In light of NRDC’s comment, it appears that th ere is broad support for th e concept that it is appropriate to create a subcategory for a group of sources that have a fundamentally different limestone mercury contents based on EPA’s pr ecedent of establishing subcategories based on, among other things, technical differences in emissi ons characteristics, processes, control device applicability and opportuniti es for pollution prevention. This a pproach is consistent with EPA’s established interpretation of sub categorization as well as the go al underlying section 112, namely ensuring the use of the maximum achievable cont rol technology.Keith Barnett September 4, 2009 Page 11

2. The Data Support EPA Establishing Subc ategory for Affected Sources

With ≥ 225 ppb Mercury in Their Limestone

Based on this extensive subcategorization precedent in other NESHAPs, the data presented in Figure 1 and Table 3 of the Preamble provide strong justification fo r establishment of a subcategory based on mercury content in limestone. The data collected as pa rt of the 114 request identify two affected sources, Nos. 1629 and 1609, which bear no relationship to the data points

in the remainder of the data set. Even the mo st superficial analysis indicates that those two affected sources form a separate and distinct data set as compared to the other sources. Based on

Ash Grove’s statistical assessment of the data, the break point betw een the two data sets occurs at 225 ppb. 2 Only one other kiln was even identifie d as having limestone mercury content in excess of this value and that data point is clea rly in error based on revi ew of the underlying data and should reflect a much lower average value. Table 3 of the Preamble documents that the mercury emitted by the two affected sources in the se parate data set is almost exclusively due to mercury in the limestone with essentially no me rcury coming from fuels. As a result, the mercury is virtually entirely due to the nature of the on-site materials that are intrinsic to the kiln itself and part of the affected source. Based on agency precedent, a separate subcategory is appropriate for sources with grea ter than or equal to 225 ppb mercur y in their limestone as these sources form a different type a nd class of source from the othe r category members. EPA would be acting contrary to over 10 years of precedent if it chooses in this instance to not subcategorize based on the nature of the raw materials, chemis try formulation data, emissions characteristics and quantity of emissions. This would amount to a change in interpretation of the law and such changes in interpretation are “entitled to consider ably less deference than a consistently held agency view.” INS v. Cardoza-Fonseca , 480 U.S. 421, 446 n.3 (1987) (internal quotations omitted). Where the agency has previously subcategorized based on the same criteria and the

distinction between the two sub categories is so strong, the fail ure to subcategorize in this instance would be arbitrary and capricious.

3. Creating a ≥ 225 ppb Subcategory is Consiste nt With the Brick MACT

Decision

Establishing a ≥ 225 ppb subcategory is strongly supported by the courts. As Judge Williams

noted in his concurrence in Sierra Club v. Envtl. Prot. Agency , 479 F.3d 875, 885 (D.C. Cir.

2 Ash Grove evaluated the source category brea k point as 225 ppb by taking the average of Tehachapi and Durkee and subtracting two standa rd deviations. Ash Grove understands that PCA identified a different break point using a different methodology. Ash Grove believes that while either methodology provides a rational means of distinguishing the two data sets, from a policy perspective it is pr eferable to employ the higher value. For that reason, in this letter we identify the subcategories in relation to a 225 ppb break point.Keith Barnett September 4, 2009 Page 12

2007) ( Brick MACT ), “one legitimate basis for creating additional subcategories must be the interest in keeping the relation between ‘achie ved’ and ‘achievable’ in accord with common sense and the reasonable meaning of the statute.” Judge Williams’ language is prescient in this

case where the difference between the ability to comply of the ≥ 225 ppb sources is so markedly

different from all of the other sources. EPA ev en identifies in the preamble the paradox that while the Durkee kiln is in the process of instal ling the best known mercur y controls (currently anticipated to start controlling mercury in early 2 010), the plant will likely be forced to close if the standard is promulgated without subcategor ization. Preamble at 21148 (“[The Durkee kiln] has voluntarily entered into an enforceable agreem ent to install activated carbon (the best control technology currently available so far as is known) to control its mercury emissions. *** Closure of this kiln and possibly other high merc ury emitting kilns is a possible consequence of a single standard without subcategories.”). Drawing from the language in Judge Williams’ Brick

MACT concurring opinion, EPA must create a ≥ 225 ppb subcategory as “one legitimate basis for creating additional subcategories must be the interest in keeping the relation between “achieved”

and “achievable” in accord with common sense a nd the reasonable meaning of the statute.”

Brick MACT at 884-85.

4. Creating a ≥ 225 ppb Subcategory is Consistent With the Legislative History

of the Clean Air Act

This approach is consistent with the legislative history of the Clean Air Act. As the D.C. Circuit recognized in the Primary Copper Smelter NESHAP decision, “the substitution of cleaner ore stocks was not, in any event, a feasible ba sis on which to set emission standards...[where] metallic impurity levels are variable and unpred ictable both from mine to mine and within specific ore deposits.” Sierra Club v. EPA , 353 F.3d 976, 988 (D.C. Cir. 2004) (“ Copper Smelter MACT”) . This statement relates closely to di scussions that occurred when Section 112 was developed by Congress. When 112(d) standa rds were developed, the possibility of requiring substitution of cleaner ore stocks was considered. In the Conference Committee report, Congress stated that “the Administ rator shall not consider the subs titution of, or other changes in, metal- or mineral-bearing raw materials that are being used as feedstocks or material inputs...” Conference Committee Explanatory Statement. This statement shows that it was never Congress’ intent to require a mi ne-mouth industry, such as a cement plant, to physically move so

that it could utilize a different f eedstock. However, as the D.C. Circuit has made equally clear, that directive must be read in conjunction with the statements in the Act that the floor must be established based on the best performing 12 pe rcent of the existing sources. The way to

harmonize these directives for the Portland Cement NESHAP is to establish a subcategory that is cognizant of the feedstock attri butes and to establish a floor accordingly. EPA can then go beyond the floor in determining the appropriate st andard for that particular subcategory. The

Conference Committee statement is not intended to exempt sources from the NESHAPs, but rather to ensure that, in Judge Williams’ wo rds, EPA maintains “the relationship between

‘achieved’ and ‘achievable’ in accord with co mmon sense and the reasonable meaning of the

statute.” Brick MACT at 885.Keith Barnett September 4, 2009 Page 13

Congress’ intent in relation to subcategorization is also made clear in the Senate Report

associated with the 1990 Amendments. The Senate Report states that “t he Administrator may

take into account factors such as industrial or commercial category, facility size, type of process

and other characteristics of sources which are likely to affect the feasibility and effectiveness of air pollution contro l technology.” S. Rep. No. 228, 101st Cong., 1 st Sess. 166 (1989) (emphasis added). It also notes that “where a group of sources may share the characteristics of other sources in the category, the Administrator may establish subcategories for such sources.” Id

. Pollutant concentrations in raw materials upon which sources must rely are certainly such “characteristics” of the sources that may lead to a determination of a ppropriate “classes” or “types” of sources. A kiln and the collocate d quarry upon which it relies must be viewed together when determining the class or type of source. Put another way, two different kilns at different locations that rely upon limestone deposits with si gnificantly different mercury

concentrations should not be c onsidered “similar sources” under § 112(d)(3). Using mercury concentration in the limestone is an equally appropriate means of subcategorization as subcategorizing for different coatings which have different levels and types of volatile HAPs in them (see, Subpart PPPP for an example of diffe rent coatings being placed in different subcategories based on the VHAP makeup of th e coating; 67 Fed. Reg. 72288 (Dec. 4, 2002)).

Congress’ intent in relation to subcategorization is similarly made clear in the House Report

associated with the 1990 Amendments . The House Report states that:

“The Committee expects MACT to be meaningful, so that MACT will require substantial reductions in em issions from uncontrolled levels. However, MACT is not intended to require unsafe control measures, or to drive sources to the brink of shutdown .” House Rep. No. 101-490, Part 1, at 328 (M ay 17, 1990) (emphasis added).

This passage evidences a clear intent for EPA to ta ke such measures that are consistent with the language of the Act to ensure th at the NESHAP program does not re sult in plant closure. Read in conjunction with Judge Williams concurring opinion in the Brick MACT decision, there is a clear mandate to create a subcategory for the ≥ 225 ppb sources and prevent the closure of the Durkee and Tehachapi plants predicted by EPA if the standard is promulgated as proposed. Preamble at 21166 (“These retirements include two k ilns that we have determined may close due to not being able to meet the mercury emission limits due to unusually high mercury contents in their proprietary quarries (i.e., the mercury content of the raw material at limestone quarries)”).

5. Ash Grove’s Durkee Plant Merits Creation of a Subcategory

The justification for a subcategory for the ≥ 225 ppb sources is particularly forceful in relation to Ash Grove’s Durkee, Oregon plant. Ash Grove’s Durkee plant, like most cement plants, reliesKeith Barnett September 4, 2009 Page 14

on limestone that is removed from a collocated quarry. 3 This limestone has elevated levels of naturally occurring mercury. In late 2006 Ash Grove voluntarily performed extensive testing to better understand the nature and magnitude of its mercury emissions. This constituted some of the most advanced and comprehensive mercury stack and raw material tes ting ever performed at a cement plant. Ash Grove engaged national expert s to perform multiple different types of tests using a variety of test methods so as to increase the company’ s understanding of the quantity and type of mercury emitted from the plant. The stack testing indicated that the vast majority of the mercury was either oxidized mercury or elemen tal mercury, with elemental mercury making up as much as 70 percent of the total.

Ash Grove voluntarily decided to develop mercur y emission controls for its Durkee plant. Ash Grove knew that no cement plant in the countr y had installed controls for the purpose of reducing mercury emissions. Five kilns in the country have wet scrubbe rs to control sulfur dioxide emissions and some of these controls ap pear to provide a moderate level of mercury

control. 4 Wet scrubbers are ineffective on elementa l mercury as elemental mercury is not water soluble. Given that up to 70 percent of the merc ury at the Durkee plant was shown to be in the elemental form, a scrubber is not an optimal c ontrol device. Ash Grove also understood that scrubbers (which consume millions of gallons of water per year) are no t a practical control technology in the arid western U.S, where water is scarce. Therefor e, Ash Grove realized that it was going to have to develop a means of controll ing mercury that was previously unknown in the industry. Ash Grove engaged the experts at EE RC, a research center associated with the University of North Dakota that had extens ive experience developing mercury control and monitoring techniques in the electrical generation sector. Ba sed on the stack test data, the EERC researchers proposed the use of an activated car bon injection (“ACI”) system to control mercury
emissions. Ash Grove invested over $1 million to have EERC temporarily install a pilot ACI

3 EPA acknowledged in the proposed rule that quarri es are virtually always collocated with the affected source and that the quarry is th erefore part of the affected source:

“All cement plans have a limestone quarry located adjacent to or very close to the cement plant. This quarry supplies limestone only to its associat ed plant, and is not accessible to other plants. Typically quarries are developed to provide 50 to 100 years of limestone, and the cement kiln is located based on the location of the quarry. See 70 FR at 72333. For this reas on, we believe that a facility’s proprietary quarry is an inhe rent part of the process su ch that the kiln and the quarry together can be viewed as th e affected source.” Proposal at 21145.

4 EPA’s data indicate that th e scrubbers achieved between 0 a nd 81 percent control during the sources test periods. These data do not suggest any level of c ontrol can be assumed across the industry and they do not account for the re-emi ssion of mercury documented to occur in wet

scrubbers.Keith Barnett September 4, 2009 Page 15

system at the Durkee plant. EERC was at the pl ant installing and operating the pilot system for over six weeks. A small percentage of the e xhaust gas (~1 percent) was removed from the ductwork after passing through the plant’s main ba ghouse. This gas was routed through the ACI system and the emissions entering and exiting the system were carefully studied. Based on this

in situ study EERC predicted that if the performance of a full scale system matched that of the pilot system, Ash Grove could reduce mercur y emissions by approximately 75 percent on an annual average basis. The EERC data suggested that there could be ma terial variability in control on a day to day basis (a conclusion suppo rted by the PCA variability analysis of the available CEM data). As a result, any standard based on a 30 day rolling average will be more stringent than a standard based on an annual average.

Although Ash Grove believed that the EERC st udy had developed the optimum system design, the company conducted a peer review of EERC’s work with a broad array of stakeholders. Through a partnership with local residents, environmental groups, Tribes and the state environmental and health agencies, Ash Grove went through a long and public process to determine the best means of addressing mercury emissions. What ultimately was approved by

this diverse team was the insta llation of an activated carbon injection system with a recirculation loop and mercury recovery. This system ach ieves maximum mercury control with minimum waste generation and minimizes the transfer of th e mercury from one released media to another

released media. These controls are anticipated to achieve a system removal efficiency of at least 75 percent. However, Ash Grove voluntarily entere d into an enforceable order with the state to not only achieve 75 percent control, but to also strive to impr ove the SRE to as close to 85 percent as reasonably possible. To further ensure the public’s knowledge and approval of this type and level of control, the enforceable order was placed on public notic e with the opportunity to submit comments. In addition, a public hearing was held about the terms of the order. In the end, the order was finalized with the 75/85 percen t control requirements determined appropriate by the advisory committee. This level of merc ury control has previous ly been considered unattainable in the cement industry and Ash Grove is well into construction on the controls that will establish the state of the art for mercury control technology on cement kilns. Absent negative impacts from the Portland Cement NESHAP rulemaking, Ash Grove anticipates commencing operation of these contro ls in approximately April 2010.

6. Apply a Beyond the Floor Standard to the ≥ 225 ppb Subcategory

Ash Grove believes that the most sound means of addressing the affected sources with high mercury limestone is through sub categorization and th e establishment of a 112(d)(2) standard that requires beyond the floor cont rols. If EPA establishes a ≥ 225 ppb subcategory, there will be

two sources in this database for evaluation in se tting the floor. This fl oor emission rate would equate to a relatively high value in comparison to the standard applicable to the other sources in the category. However, EPA could then choose to go beyond the floor and establish a standard

that reflects the Durkee kiln’s use of ACI. As noted above, EPA would be on sound footing if it created a subcategory based on the two ≥ 225 ppb plants and required be yond the floor control. As Judge Williams noted in his Brick MACT concurring opinion, if th e statute produced a resultKeith Barnett September 4, 2009 Page 16

demonstrably at odds with the intentions of its drafters, it would “justif y judicial surgery.” Brick

MACT at 885. It would seem demonstrably at odds with the drafters’ in tentions to impose a standard on a plant that it ca nnot comply with even when using the most advanced mercury controls on any cement kiln in the country. For that reason, we belie ve that it is appropriate for EPA to establish a separate subc ategory reflective of th e two unique facilities and to establish the floor based on those plants’ mercury emission le vels. EPA could then go beyond the floor to

account for the actual emission rate that will be achieved throu gh the Durkee plant’s extraordinary efforts to control mercury emissions . The emission standard could also be crafted to include work practices prohibiting the use of o ff-site raw materials containing material levels of mercury (e.g., fly ash) and, as discussed belo w, requiring dust shuttling up to the maximum

level that does not impact product quality.

7. Material Reductions Beyond Those Achi evable by ACI Cannot be Reliably

Estimated or Achieved

In establishing the “beyond the floor” standard for

the ≥ 225 ppb affected sources, the standard should not be more stringent than what is required of the Durkee kiln in its Order. As discussed above, the Durkee kiln must meet a minimum 75 percent mercury removal efficiency and take all reasonable measures to achieve an 85 percent removal efficiency. Ash Grove’s extensive analysis has concluded that it cannot provide

material levels of control in excess of what is expected to be derived from installation of the ACI system. Ash Grove has assessed the following different means of potentially further decreasing mercury emissions at the Durkee plant: 1) selective mining (i.e., removal and wasting of high mercury ore and only using low mercury ore), 2) use of a scrubber in series with the ACI system, 3) “dust shuttling,” and 4) limestone scrubbing. Ash Grove’s anal ysis of each option is

described below.Keith Barnett September 4, 2009 Page 17

i. Selective Mining

In order to understand th e challenges of selective mining in a quarry, it is critical to understand the geologic history that resulted in limestone with elevated me rcury levels. Mercury tends to naturally occur at elevated levels in locations wi th a history of geothermal activity. Mercury is a

crustal element that is distribu ted throughout the planet (the av erage mercury concentration in the earth’s crust is approximately 80 ppb). 5 However, there are some places where mercury is concentrated at higher levels near the surface (i.e ., within the top mile or two of the earth’s surface). Although there are different theories for why that occurs, the leading theory is that it has to do with historic geothermal activity in th e aftermath of tectonic plate movement. Metals with low boiling temperatures (e.g., gold, merc ury) are volatilized by magma caused by the tremendous heat of friction resulting from the gr inding of tectonic plates where they meet. The magma results in superheated steam intermixed w ith the volatilized metals. This mixture is channeled towards the surface through pathways in the rock. Where rock is heavily fractured as the result of historic folding, faulting and intr usions, it provides conduits for the mineralized solutions. The metals then condense in the uppe r fractured rock layers . Recurrent fracturing opens new conduits and shifts the existing one s so that the mercur y becomes distributed randomly over the zone. As the result of tecton ic activity during the Me sozoic period (starting about 251 million years ago), an island arc was a ccreted and the associated deformed strata created a orogenic belt that extends up through pa rts of California, goes through the southwest corner of Oregon before disappe aring under lava cover and resu rfacing in northeastern Oregon. This belt is heavily fractured and has a history of geothermal activity that resulted in the deposition of gold and mercury throughout the band. Ash Grove’s Durkee plant is located in the

northern section of the belt while the other affected source in the ≥ 225 ppb subcategory (Lehigh

5 From Sources and Receptors of Mercury (Idaho, January 28, 2009).

“ Regional Soil Emissions It is important to note that the earth’s crust naturally contains approximately 80 parts per billion of mercur y (Mason 1966), and it is widely recognized that even “clean” soils with background concen trations of mercury release volatile mercury to the air (Gustin et. al. 2008). Th is is especially important in the west where soil mercury concentrations can be enhanced by local ge ology (Zehner and Gustin 2002, Gustin et. al. 2000), and Idaho is no exception. A prelimin ary, very conservative estimate of background soil emissions in Idaho suggests that soil emissions of mercury in Idaho could be of the same magnitude as the sum of a ll industrial sources in the state (Lindberg, 2008). The most comprehensive measurements of so il emissions of mercury have been done in

Nevada where the authors cited above estima ted annual releases of ~3.8 T/y, more than 14 times greater than the curre ntly reported industrial emissi ons in Idaho (Gustin, et al. 2008). The same authors estimate that natural mercury emissions from mineralized areas

in the western U.S. as a whole are 10 to 20 tons/year, or more than 38 times greater than the currently reported industrial emissions in Idaho.”Keith Barnett September 4, 2009 Page 18

Cement Company’s Tehachapi, CA plant) is loca ted in the southern portion of this belt. The portion of the accretion that makes up the Blue Mountains is surrounded on the north, west and south by basaltic flows that occurred comparatively recently as a result of sh ield flooding of lava during the mid-Miocene period. As a result, the Blue Mountains are largely surrounded by a zone of basalt layers that are not conducive to geothermal activ ity and possess neither limestone nor the elevated levels of mercury found within the Blue Mountain belt. As Figure 1 indicates, the orogenic belt that starts in the Blue Mountains and extend s down into Southern California has similar geologic characteristics. 6 Unsurprisingly, the cement plants with elevated mercury naturally occurring in their limestone deposits are both situated in this belt. The plants located in this belt (or similarly co nfigured areas of the country if any are found in the future) should be part of a separate subcategory unde r the Portland Cement NESHAP.

The very geologic attributes that resulted in mercury being elevated in these parts of the western U.S. also resulted in the mercury being randomly di stributed across the quarri es in these areas. The highly fractured nature of the limest one in the orogenic belt underlying the two ≥ 225 ppb affected sources is the reason why the mercury la den thermal solutions were deposited in these area. These fractures continued beyond the time period where the mercury was deposited. As a result, the mercury is diffused across the deposits and there is no reasonable means of seperating higher mercury limestone from lower mercury li mestone. Several years of data from Ash Grove’s Durkee quarry support this statement. Starting in 2007, Ash Grove began collecting monthly composite samples of the limestone re moved from its quarry (see, Table 1 above). Mining is performed on benches, with Ash Gr ove moving up and down the working face of the quarry, blasting roughly 40,000 ton “shot s”. The data from this sampling is telling. First, it shows that the ore varies considerably on a month-to-month basis ranging from 424 ppb to 1,740 ppb. In order to determine whewther there wa s some means to pred ict and avoid higher

concentration areas in the quarry, Ash Grove then mapped the mercury concentrations, correlating them with the quarry areas being wo rked. As Figure 2 below shows, there is no predictability to where in the quarry one will fi nd higher v. lower concentrations of mercury in the ore. To evalaute the same question on a hi gher resolution, Ash Grove also evaluated ore removed when drilling blast holes in one individual shot was prepared for blasting at the quarry. As Figure 3 shows, the mercury concentrations acro ss the individual shot were strikingly diverse. Ore with 2,790 ppb was 50 feet from ore with 53 9 ppb; ore with 1,250 ppb was 10 feet from ore with 767 ppb. The clear conclusion from this sa mpling is that mercury levels can change dramatically by moving just a few feet across the top of an indi vudual bench and is unpredictable across the entirety of the quarr y. As a result, Ash Grove ha s concluded that there is no reasonable basis for trying to selectively mine or e so as to decrease the mercury of its raw feed.

6 Figure reproduced from W.R. Dickenson, Cordilleran Sedimentary Assemblages; Early Mesozoic-Tectonic Evolution, (1992)Keith Barnett September 4, 2009 Page 19

Figure 2: Mercury Levels in Durkee Quarry 2007-2009Keith Barnett September 4, 2009 Page 20

ii. Serial Scrubber

Another possibility Ash Grove evaluated for potentially obtaining additional mercury reduction

was the use of a wet scrubber in series with the ACI system. The ACI system functions as a dry mercury scrubber. However, wet scrubbers showed some ability to decrease mercury emissions

and so Ash Grove assessed whether the addition of a wet scrubber in line with the dry scrubber (i.e., ACI) would result in enhan ced control. However, as noted above, wet scrubbers only control oxidized mercury as elemental mercury is not water soluble. Give n that testing at the Durkee kiln indicated that up to 70 percent of the mercury is in the elemental form, a wet scrubber is not going to provide a material amount of additional control. The ACI system is predicted to control high levels of the oxidized mercury as well as promote the oxidation of the elemental mercury. Therefore, no material additi ve benefit would come from the use of a wet scrubber. In addition, wet scrubbers require m illions of gallons of water per year—Ash Grove Figure 3. Mercury Sampling Across a Single Blast Area (Shot)Keith Barnett September 4, 2009 Page 21

estimates that a wet scrubber appropriate for th e Durkee plant would cons umer approximately 21 million gallons per year. The annual rainfall in Durkee, Oregon is approximately 8 inches per year and there is simply no availability of water for use in a wet scrubber. Therefore, both for

the reason that a wet scrubber woul d not provide a material benefit when run in series with the ACI system and because water is not available in the area, Ash Grove concluded that a wet scrubber is not meaningful control technology with which to supplement the efficiency of the ACI system.

iii. Dust Shuttling

One approach which conceivably could provide a small additional boost in control efficiency at the Durkee plant is bleeding a percentage of the dust collected in the primary baghouse into the finished product. Ash Grove’s research suggests that mercury is scrubbed in the raw mill when the “waste” heat in the kiln gase s is used to dry incoming raw fee d. It is theorized that mercury condenses onto the incoming raw materials and is th en passed into the kiln where it re-volatilizes and is exhausted again through to the raw mill. When the raw mill is shut down, as must occur periodically for routine maintenance, the raw ma terial scrubbing is temporarily stopped and the mercury “stored” in the raw mill system is exha usted. However, the raw mill is not a perfect scrubber. Therefore, at all times there is me rcury that makes it through the raw mill and out the main stack. Some small portion of that mercury c ondenses on particulate pr ior to being captured by the baghouse. In addition, some raw materi al with condensed mercury on it is exhausted through to the main bag house. Normally, all of the material (i.e., uncalcined limestone) captured in the primary baghouse is returned direc tly to the process as it constitutes valuable raw feed in which a significant processing invest ment has occurred. The concept behind dust shuttling is that a percentage of the uncalci ned limestone caught in the primary baghouse is continually bled off to the finish mill, rather than the raw mill, and intermixed with cement. 7

Ash Grove has determined that the ability to intergrind uncalcined limestone captured in the primary baghouse into cement in the finish m ill is limited by the performance standards which Ash Grove’s cement must satisfy to be salable. Most state Departments of Transportation (“DOTs”) specify that cement must meet the speci fications of the American Association of State Highway and Transportation Officials (“AASHT O”) and the specifications of ASTM C150. These specifications, which were recently ha rmonized, include requirements for insoluble residue ( ≤ 0.75 percent), loss on ignition ( ≤ 3.0 percent), limestone addi tion (5 percent maximum) and process addition (5 percent maximum), among others. In ev aluating the ability to shuttle uncalcined limestone from the primary baghouse it is necessary to ensure that the resulting

cement meets these standards or else Ash Grove risks having unmarketable product. These standards pose several significant ch allenges to dust shuttling. Fi rst, it has not been established

7 The Durkee plant does not have an alkali bypass and so any uncalcined limestone removed from the process must be removed at the primary baghouse.Keith Barnett September 4, 2009 Page 22

if baghouse dust would be considered “process add ition” or “limestone addition.” The definition

of limestone under ASTM C150 states that the ma terial must be naturally occurring with a calcium carbonate content of at least 70 percen t, making it unclear whether baghouse dust meets

the definition of limestone. Given that the baghouse dust is uncalcine d limestone, it appears likely the dust would meet that definition. Howeve r, the way the limestone content of cement is determined may make the point moot. ASTM 150 st ates that the limestone content of cement is

calculated from the CO 2 analysis of the cement. The manufacturer must include the CO 2 content
of the cement and the CO 2 content of the limestone in the Mill Test Report. The percent of

limestone in the cement is defined as:

(% CO 2 in cement)/(CO 2 content in limestone) x 100 = % limestone in cement

Since both baghouse dust and limestone generate CO 2 on ignition, when the limit of 5 percent is

reached no additional CO 2 producing material can be added.

Another challenge to shuttling uncalcined lime stone from the baghouse relates to the limits placed on loss on ignition (“LOI”). Both the ASTM and AASHTO standard for the LOI for cement is 3 percent by weight. This includes th e loss after the addition of limestone or process material; all specifications of the cement must be met after any limestone or process additions.

The normal LOI for cement is about 1 percent by weight before a ny additions. The LOI is from the addition of gypsum. Therefore, any additional LOI could not c ontribute more than 2 percent by weight. The LOI of baghouse du st is normally between 33-36 percent. Table 2 below shows the amount of baghouse dust that can be added to cement with a LOI of 1 percent such that the

total LOI of the cement will be 3 or less:

Table 2. Evaluation of Bagh ouse Dust Impact on LOI

LOI of Cement LOI of Baghouse Dust % Dust Added for Total

LOI of 2%

1% 33% 3.12 %

1% 36% 2.86%

This table suggests that a maximum of approxi mately 3 percent baghouse dust can be added to cement in order to pass the LOI specification. This is less than the cem ent specifications for limestone or process addition allows. In other words, the LOI specification is more stringent.

Another factor to consid er is the insoluble residue. Insolu ble residue for cement is defined as that portion of cement that is not soluble in either acid or base . The contributors to insoluble residue are generally the silica a nd clay components of cement. The specification for insoluble residue is 0.75 percent by weight. Normal ceme nt with any additions will have an insoluble residue of about 0.3-0.4 percent. Without consid ering other constituents, baghouse dust contains about 12-15 percent silica, which will appear as insoluble residue in the cement. Table 3 belowKeith Barnett September 4, 2009 Page 23

shows the amount of baghouse dust that can be a dded to cement without exceeding the insoluble residue specification.

Table 3. Evaluation of Baghouse Dust Impact on Insoluble Residue

Insoluble Residue Cement (%) Insoluble Residue Dust (%)) % Dust Added for

Insoluble Residue 0.75 %

0.3 12 3.85

0.3 13 3.54

0.4 12 3.00

0.4 13 2.77

This table illustrates that, besides the LOI speci fication, the insoluble residue also has a limiting

effect on the amount of dust that can be added to cement, particularly when the dust contains large amounts of silica such as is the case with kiln baghouse dust. No consideration was made concerning other materials in the baghouse dust that might lead to insoluble residue. However,

there are other materials th at will have an effect.

Although the desktop assessment of limestone shuttling suggests that up to 3 percent baghouse dust can be used and still maintain quality, the actual experience of one kiln suggests that the actual value is an order of magnitude lower. The discussions above suggest that uncalcined limestone from the baghouse can only make up, at most, about 3 percent of the cement in order to conform to the AASHTO and ASTM specificati ons. However, the Lehigh Cement plant in Union Bridge, Maryland has performed extens ive testing with intergrinding uncalcined limestone from the plant baghouse and determined that it cannot include mo re than 0.3 percent dust in its finished product without adversely impacting produc t quality. A commitment to intergrind that amount of baghouse dust was recently memorialized in a C onsent Decree with the Maryland Department of the Environment. Th is practical experien ce with intergrinding uncalcined limestone from the baghouse carries more weight than the desktop analysis outlined above. Lehigh’s practical experience also show s the unpredictability of dust shuttling and the need to assess the work practice on a plant specific basis in order to be able to accurately assess the amount of baghouse uncalcined limestone that can be added to particular products from particular kilns without impacting qualit y and creating a potential safety hazard.

Ash Grove recognizes that while dust shuttling will not cause the Durkee plant to meet the proposed mercury standard, every additional pe rcent of mercury reduction is good. However, Ash Grove also recognizes, as has EPA, that the experience does not exist that would allow anyone to predict the removal efficiency attribut able to dust shuttling. As EPA noted in the proposed rule preamble in relation to the wasting of Cement Kiln Dust (“CKD”) 8 :

8 Our discussion of dust shuttling is focuse d on the application of the process to a preheater/precalciner kiln. In preheater/precalcin er kilns, CKD, if it is produced at all, is (continued . . .)Keith Barnett September 4, 2009 Page 24

“However the degree to which CK D can be used to reduce mercury emissions cannot be accurately estimat ed due to several factors. For example, increasing the amount of CKD wasted would result in a reduction in the mercury concentration of the CKD, so that, over time, the effectiveness of wasting C KD decreases. We do not have longterm data to quantify the relations hip between amount of CKD wasted, CKD mercury concentration and emissions.

“The ability to reduce mercury em issions by wasting more CKD also is affected by the mercury species present. The particulate and oxidized species of mercury can a ccumulate in CKD, but not the elemental form. Therefore wasting CKD will not necessarily control elemental mercury. We do not have data that would allow us to quantify the effect of mercury speci ation. By wasting CKD, additional raw materials would be required to replace the CKD as well as additional fuel to calcine the additional raw materials, thereby offsetting to some extent the benefits of wasting CKD. There is the further potential consideration of additional waste generation, an adverse cross-media impact EPA is required to consider is making beyond-the-floor determinations. The interaction of th ese factors is complex and has not been adequa tely studied.” Preamble at 21150.

(. . . continued) generated at the bypass duct which bleeds off gases di rectly after leaving the kiln and before they

encounter the raw material feed into the kiln. Th is CKD is wasted in order to decrease the alkali content of the clinker. Modern preheater/pr ecalciner kilns are desi gned to minimize the generation of CKD. Ash Grove’s Durkee kiln, fo r example, is a modern preheater/precalciner kiln that does not generate CKD. By contrast, in wet kilns, all of the material captured in the primary particulate control device is typically wasted as CKD because it is too difficult to reintroduce the material into a wet process. For long dry kilns there is the potential to reintroduce primary particulate control material and avoid the generation of CKD if there are no alkali problems based on th at plant’s raw materials. CKD that is wasted from a preheater/precalciner kiln (i.e., alkali bypass dust) c ontains essentially only the mercury from the

fuels fired in the kiln that have condensed out on the dust captured in the alkali bypass control device (i.e., on the CKD). The mercury in the ra w material introduced into the preheater tower will have volatilized prior to reaching the bypass duct and so will never be controlled through management of CKD. While the data does not ex ist to predict with any accuracy the ability of primary baghouse dust to control mercury, the technique could yield better results in a preheater/precalciner kiln than the intergrinding of CKD. However, in situ study is required before the benefits can be quantified.Keith Barnett September 4, 2009 Page 25

This passage indicates that the potential the bene fits of intergrinding CKD are highly speculative. This is equally true for the wasti ng of primary baghouse dust, although for a preheater/precalciner kiln the potential benefi ts could be greater than for other kiln configurations. The discussion above also makes it clear that shuttling primary baghouse dust displaces the ability to add limestone that has not gone thro ugh the initial raw feed processing steps. This practice will ultim ately reduce the efficiency of a kiln and increase CO2 emissions for each ton of cement produced. While Ash Grove recognizes that it is appropriate to consider all reasonable measures when evaluating be yond the floor technologies, the absence of experience with dust shuttling and the highly si te specific nature of the benefits makes it impossible to accurately predict the level of control that coul d be achieved. Clean Air Act Section 112(h)(1) provides for this type of situati on. Where it is not feasible to prescribe or enforce an emission standard, EPA can issue a wo rk practice. Because the specific emission

reduction attributable to dust s huttling cannot be practically pr escribed or enforced, dust shuttling is best addressed as a 112(h) work prac tice. Therefore, Ash Grove supports the concept of adding the work practice of dus t shuttling to the beyond the floor requirements for the sources

in the ≥ 225 ppb subcategory. However, the work practi ce requirement must specify that while a

≥ 225 ppb source shall implement dust shuttling, it must only do so up to the maximum level achievable without negatively aff ecting product quality. Any re quirement that would impact product quality would not only be an unreasonable requirement to impose on the affected source, but would endanger the safety of the people w ho rely on the properties of the cement.

iv. Ore Scrubbing

Another conceptual possibility for reducing me rcury emissions from affected sources that include quarries with elevated merc ury levels is to implement some sort of limestone scrubbing. Under this concept, mercury would be removed fr om the limestone prior to its introduction into the kiln system. Ash Grove is aware of no commer cially available system that purports to reduce the limestone mercury content. The concept of or e scrubbing was previously raised in relation to the Primary Copper Smelter NESHAP. In that instance there was si milarly no commercially available system and the D.C. Circuit held that it was appropriate to not consider a possible means of control that was not commercially available. Copper Smelter MACT at 989. For the same reasons, this conceptual possibility has no place in this rulemaking.

v. Conclusions About Control System Performance Enhancement

In summary, it does not appear th at there are any additional contro l methods that could be relied upon to materially increase the control efficiency of the ACI system by a predictable enough amount that they can be incorporated into the nu meric standard. Therefore, we believe that 75 percent is the appropriate beyond the floor control efficiency to apply in establishing the

emission standard for the ≥ 225 ppb source category.Keith Barnett September 4, 2009 Page 26

Ash Grove recognizes that while there may be no basis for increasing the mercury control efficiency in a predictable enough manner to make it a component of the floor’s numeric standard, additional reductions could be addresse d through work practices. Section 112(h) of the Clean Air Act allows EPA to set work practice standards when it is not practicable to measure emissions. For the reasons stated above, it is not pr acticable to measure emi ssions at this point in

time associated with dust shuttl ing. However, in going beyond th e floor it would be possible to establish dust shuttling as a work practice to achie ve additional control. Dust shuttling could be required up to the maximum level that will not impact product quality. While the improvements in mercury control cannot be predic ted or measured at this time, the ultimate reductions could be material. Therefore, it makes sense to include dust shuttling as a work practice. Likewise, Ash Grove believes that it is appr opriate to include a mercury cont rol enhancement plan as a work practice. After extensive review of the technol ogy by an independent group of technical experts, health professionals and repr esentatives of environmental groups and Tribes, Ash Grove voluntarily entered into an enforceable order me morializing its commitment to install at the Durkee plant the most advanced mercury controls planned for any cement plant in the world. After reviewing the extensive pilot testing performed at the Durkee plant, this expert group concluded that 75 percent mercury control was the best estimate of a reliable level of control, taking into account the variations between raw mill on and raw mill off conditions. However, the group was optimistic that as knowledge grew about the ACI system’s interplay with the mercury cycle, that a higher level of control w ould be possible. Therefore, the group suggested, and Ash Grove agreed, to include in the order a requirement for As h Grove to take all reasonable measures to enhance the performance of the co ntrol equipment such that it reached 85 percent control. If the plant is not able to achieve 85 percent control, it must su bmit a plan describing the steps it will take to evaluate further measures that can reach the target. The specific language of the order relating to this Control Enhan cement Action Plan is reproduced below:

“The 85% goal : At all times af ter completion of shakeout as described in Paragraph 8.B.VI, Ash Grove agrees to endeavor to meet a goal of 85% reduction in mercury emissions on a rolling 12-month averag e basis, calculated as described in Paragraph 8.A. If Ash Grove’s emissions are below 85%

reduction for the rol ling 12-month average for any successive four month periods occurring who lly after the shakeout period, Ash Grove agrees to take the following steps:

“i. Within 45 days of the la st day of the last of the

successive four months in which Ash Grove did not achieve the 85% reduction, Ash Grove agrees to

submit an Action Plan to the Department for approval. The Action Plan must evaluate

reasonable alternative methods to reduce the mercury emissions, including identifying the optimal carbon injection ra tes, and propose a planKeith Barnett September 4, 2009 Page 27

and implementation schedule to achieve the 85% reduction; and “ii. Upon the Department’s approval of the Action Plan, Ash Grove agrees to implement the corrective

actions identified in the Action Plan according to

the schedule in the Action Plan. “iii. If the Departme nt agrees in writi ng that Ash Grove

has exhausted all reason able alternatives for meeting the 85% goal, Ash Grove need not submit

further Action Plans.

“iv. Ash Grove’s failure to achieve the 85% reduction

will not be considered a vi olation of this Order.” Mutual Agreement and Or der Executed Between Oregon Department of E nvironmental Quality and Ash Grove (July 17, 2008).” 9

Ash Grove believes that a similar requirement to pursue all reasonable alternatives to increase the control device performance to 85 percent is an appropriate work practice to be included in this beyond the floor standard.

For the reasons set forth above, we believe that it is appropriate for EPA to add an additional subcategory reflecting the two affected sources with limestone mercury content ≥ 225 ppb. This subcategory should establish the emission stan dard by going beyond the floor and taking into

account the controls under construc tion for the Durkee plant. Ther e is no basis to assume that control beyond 75 percent is achievable. Howeve r, consistent with the requirements in Ash Grove’s Durkee plant consent order, the rule can require a Control Enhancement Action Plan as a work practice to maximize the possibility of controls reaching their full potential. This approach ensures the development of the new activated carbon injecti on control technology and restricts the plant to operating in a manner consistent with the goa ls of Section 112 of the Clean

Air Act.

8. Beyond the Floor Compliance Demonstration Method

In establishing the beyond the fl oor emission standard for the ≥ 225 ppb on-site limestone subcategory, Ash Grove encourages EPA to es tablish a compliance demonstration method based on a system removal efficiency. Ash Grove unde rstands that there could be concern with a

9 Ash Grove also notes that the Order requires that Ash Grove commence controlling mercury at the Durkee plant no later than Ju ly 17, 2010. Ash Grove is current ly on schedule to beat that deadline by several months. This will result in mercury control commencing years before what would be required under the proposed rule.Keith Barnett September 4, 2009 Page 28

standard based on elevated limestone levels a nd the theoretical potential for on-site limestone

levels to decrease over time. If limestone mercur y levels were to decrease, the stringency of the

standard could decrease as well. While Ash Grov e is unaware of any sugge stion that this will occur with its own limestone, we be lieve that there is a simple m eans of allaying that concern. Specifically, EPA could require th at affected sources in the ≥ 225 ppb subcategory demonstrate compliance by meeting work practice requirements a nd achieving an overall control efficiency of 75 percent or greater. The work standards w ould be to: 1) not use fly ash, 2) conduct dust shuttling to the maximum extent possible wit hout impacting product qua lity, 3) implement a mercury minimization plan to minimize mercury in the raw materials imported from off-site, and 4) implement a Control Enhancement Action Plan to ensure all reasonable measures are taken to maximize control efficiency. The control effici ency would be demonstrated through continuous monitoring of emissions upstream and downstream of the end-of-pipe controls. By establishing limits in this manner, EPA and the public are assured that if an affected s ource is able to reduce its limestone mercury content over time, that it will not be held to a lower standard of performance.

Including this type of complia nce demonstration method is cons istent with court and agency precedent. We recognize that the Brick MACT decision requires that EPA consider both technological and non-technologica l factors in establishing the 112(d) emission standard. EPA can comply with this requirement by establis hing subcategories based on limestone mercury content. Once the subcategories are establishe d, EPA could establish th e emissions standard based on either the level of control (i.e., SRE) or the level of emissions based on nontechnological factors in the abse nce of control technology. In the Brick MACT decision the court held that it was improper for EPA to exclude an actual proven cont rol technology (i.e., non-DLA controls) in setting the MACT floor based on the inability of all sources to employ that technology. This holding is not re levant in setting the floor fo r a PC MACT subcategory where no controls have been demonstrated in practic e (e.g., the > 225ppb category). However, even for a subcategory where a member source has demonstr ated in practice the viability of a control technology, it is necessary to then consider both the technological control and the nontechnological factors. Where a source is ach ieving a considerable SRE from technological controls, it is consistent with both the law and common sense to consider that source at least comparable for emission standard setting purposes to a source that is employing no controls. Therefore, it would likewise be appropriate for EP A to establish the 112(d) emission standard in

terms of either emission rate or SRE.

Since the Brick MACT decision was issued, EPA has similarly concluded that it is appropriate to separately consider technological factors in establishing an emi ssion standard. EPA faced this

same issue in relation to the Hazardous Waste Co mbustor NESHAP and stated that the Clean Air Act does not require that the agen cy equate best performers with sources that have the lowest

emissions.

“Second, as a legal matter, section 112(d)(3) does not specifically address the question of whether ‘‘be st performing’’ sources are thoseKeith Barnett September 4, 2009 Page 29

with the lowest net emissions, or th ose which control HAP emissions the most efficiently. 70 FR at 59443. EPA posited the example of whether a source emitting 100 units of HAP and feeding 100 units of the HAP must be considered better performing than a source emitting 101 units of the HAP but feeding 10,000 units. Id. Indeed, floors for new sources are to be based on the performance of th e ‘‘best controlled’’ similar source. Section 112(d)(3). In the example just given, a source with control efficiency of 99.9 per cent can natura lly be viewed as better controlled than one with 0 percent control effi ciency. EPA’s decision to incorporate control efficiency (i.e., system remo val efficiency) into the SRE Feed methodology as one of the two f actors used to identify best performing/best controlled sources r easonably reflects that the statute allows performance to be evaluated in terms of control efficiency.” 72 Fed. Reg. 54875, 54882 (Sept. 27, 2007).

Based on this logic, it is appropr iate for EPA to establish the me rcury emissions standard with a compliance demonstration method whereby an affect ed source demonstrates that it is achieving a 75 percent SRE and is complying with a suite of wo rk practice standards. This is particularly true where, as here, this combination of m easures will achieve emission levels below the subcategory floor emission rate. 9. Consequences of Overly Stringent Standard

The unique attributes of mercury make a par ticularly compelling case for addressing the high mercury limestone sources through subcategoriz ation. Once mercury is emitted, the metal can travel significant distances. Along the western United States, it has been estimated that a substantial amount of the air depos ited mercury comes from Asia. For example, in Oregon it is estimated that approximately 83 percent of the air deposited merc ury originates from industrial activities in Pacific Rim countries. See, Clean Air Mercury Rule (C AMR) Implementation in Oregon , Oregon Department of Environmental Quality (2006). The domestic cement industry is already under siege from foreign imports and the num ber of plants in the U. S. has decreased over the past several decades despite increased domestic demand. If EPA imposes a rule that forces the high mercury limestone affected sources to cl ose due to inability to comply, the demand for cement will not change. However, the demand will be met with supply from other countries, the vast majority of which do not control mercury em issions. As a result, th e overall deposition of mercury across the western U.S. could increase as a result of plants such as the Durkee, Oregon and Tehachapi, California plant being closed due to unattainable mercury sta ndards. By contrast, if EPA establishes a subcategory for the ≥ 225 ppb sources and establishes an emission standard reflective of the Durkee plant’s controlled emi ssion rate, the aggregate mercury levels should decrease considerably. This is the clearest path towards reducing mercury emissions in the U.S. as well as globally.

Although not addressed under the NESHAP, it is also important to recognize the non-HAP environmental impacts associated with elimina ting domestic cement production at western U.S.Keith Barnett September 4, 2009 Page 30

plants. These plants serve areas that are particul arly suited to receive imports from Asia. (see Figure 4 below, depicting the existing import te rminal infrastructure on the west coast).

A study was performed by Envir on Consulting of the greenhouse impacts associated with offshoring production to Asia. This study conservatively assume d that the source of Asian cement was a plant exactly equivalent to the U.S. pl ant in terms of energy e fficiency and control. However, due to the stark differences in elect ricity sources as well as the transportation emissions, it was demonstrated that greenhouse ga s emissions would be considerably higher as a result of importing cement. Ash Grove adapte d this study for its Durkee facility to match up with the 2005 Oregon Department of Energy estimat e of the blend of generation sources. Based on this source blend, Ash Grove calculated that the greenhouse gas emissi ons associated with one ton of imported cement were more than 50 percent higher than th e same ton of cement produced at the Durkee plant. Al though we recognize that this is not directly considered in establishing MACT standards, we al so believe that it is an importa nt ancillary impact that must

be considered.

10. Recommended Action on Subcategorizati on for Purposes of the Mercury

Standard Figure 4. West Coast Ce ment Import TerminalsKeith Barnett September 4, 2009 Page 31

For the reasons set forth above, Ash Grove reque sts that EPA create two subcategories for purposes of establishing the mercury standard. One subcategory would be made up of sources with < 225 ppb mercury in their limestone and one subcategory would be made up of sources

with ≥ 225 ppb mercury in their limestone. In both subcategories, EPA should consider in establishing the floors the variability of mercury c ontent that is manifested in the limestone over

time. For the ≥ 225 ppb subcategory, EPA should establish a floor based on the two affected sources and then impose a beyond the floor require ment that all affected sources within the subcategory must demonstrate compliance by ope rating end-of-pipe controls achieving a 75 percent minimum mercury control efficiency an d by implementing the following work practices:

1) No use of fly ash as an additive in the raw feed,

2) Implementation of dust shuttling to th e maximum extent possible without impacting product quality,

3) Implementation of a Mercury Minimizati on Plan to minimize mercury in the raw materials imported from off-site, And

4) Implementation of a Control Enhancement Action Plan.

These requirements will all be consistent with bot h the letter and the intent of the Clean Air Act as well as over a decade of EPA and court precedent.

D. EPA Should Clarify that Indirect Fi red, In-Line Coal Mills Need Not Employ Mercury CEMs or Separately Demonstrate Compliance if They Vent Through a Separate Stack

Ash Grove believes that there is no basis for requiring mercury monitoring for coal mills having the configuration identified in Figure 5 below, i.e., the coal vents through a dedicated stack rather than through the main stack. 10 As discussed in greater deta il below in relation to THC, indirect fired, in-line coal mills receive their sole source of air and heat from the associated kiln (or in some cases, the clinker cooler); these uni ts have no dedicated heat source. Therefore, consistent with numerous EPA opinions, we believ e that these units are subject to the kiln exhaust standards. The proposal requires that affected source s install and operate either a mercury CEM or sorbent trap-based integrated mon itor. There is no basis for concluding that the drying of coal will increase the mercury concentr ation in the kiln exhaust that is vented through the coal mill. In order to avoid explosion haza rd, indirect fired, in-line coal mills must be maintained at temperatures below 200°F at al l times and so the temperature is too low to volatilize the mercury in the coal. See, e.g. Le tter from Donald Toensing (EPA Region 7) to

10 We note that this is not the configuration at Ash Grove’s Du rkee kiln. That kiln routes its indirect fired, in-line coal m ill exhaust through the main stack.Keith Barnett September 4, 2009 Page 32

Roger Behrns (Ash Grove Louisville), Sept ember 18, 2002 (recognizing inherent temperature limits for indirect fired, in-line coals as a ba sis for exempting units from ongoing dioxin/furan monitoring/testing). To the contrary, the em issions testing that Ash Grove has conducted on coal mill exhaust indicates that the pulverized coal acts like activated carbon and adsorbs a significant amount of the mercury in the kiln exhaus t vented to the unit. While this mercury will

be volatilized when the coal is combusted in the calciner or kiln, the mercury levels in the coal mill exhaust would never be expected to exceed the mercury levels in the main stack. Therefore, if the flow is adjusted in th e CEM/sorbent trap data acquisitio n and handling system to account for the flow in the coal mill stack, the aff ected source should be allowed to rely on the concentration of mercury identified at the main stack. Affected sources preferring to operate a mercury CEM or sorbent trap in the coal mill stac k exhaust so that they can account for the lower levels of mercury in that scrubbed slip str eam should also be allowed the option to do so.

III. Proposed Organic HAP Standard

Ash Grove does not believe that there is a reas onable factual basis for the proposed organic HAP standard. The proposed standard for new and existing sources offe rs the alternative of either demonstrating compliance with a Total Hydrocar bons (“THC”) standard or a Total Organic HAP (“TOHAP”) standard. Ash Grove has serious co ncerns regarding how these standards were established and how they would a pply to the company’s affected sources. Each concern is

outlined below.

A. Coal Mill Impacts on Exhaust Stream

The proposed organic HAP standard fails to account for a common coal mill design. As proposed, the organic HAP standard requires co mpliance with either THC limit or a TOHAP limit. These limits were based exclusively on th e THC and organic HAP content of kiln exhaust gases. Figure 5 shows a common configuration of coal mills in the most energy efficient portland cement plants. In this configuration, a fraction of the exha ust gas from a kiln is routed through the indirect fired, in-line coal mill to dry the fuel prior to storage and subsequent

combustion in the kiln or calciner. 11 The exhaust is then returned to the main stack where it is commingled with the kiln exhaus t resulting in a gas stream that contains both the characteristics of a cement kiln and a coal mill. This design is energy efficient in that it allows the coal to be dried exclusively with waste heat (there is no ba ck-up heat source and if the kiln is not operating, the in-line coal mill cannot operate). However, th is design results in the commingled gas stream having pollutant char acteristics unlik e that of kiln exhaust gases that are not routed through a coal mill. Because the organic HAP emissions of indirect fired, in-line coal mills are

11 Direct fired coal mills discharge directly into the kiln and emissions would not be distinguishable from the kiln. Our comments do not address direct fired coal mills.Keith Barnett September 4, 2009 Page 33

significantly different from the organic HAP emissi ons associated with kiln gas alone, EPA must establish different standards related to this design.

Coal

Mill

Kiln Exhaust Gas & Coal

Mill Slipstream Raw Mill 

# Figure 5

EPA guidance dating from the mid-1990s states that the emissions from an indirect fired, in-line coal mill are subject to the Portland Cement NE SHAP. In a 1995 determination, EPA stated that when “gases originate in one a ffected source and pass through anot her affected source as part of the manufacturing process, EPA applies the stan dard for the affected source from which the gases are discharged directly into the atmo sphere.” Applicability Determination 9600082 “Alternative Monitoring and Opac ity Limit Clarification for Sa n Juan Cement Company,” John B. Rasnic (May 12, 1995). However, a year late r EPA qualified this guidance when it concluded that an in-line raw mill was subject to the Subpart F kiln standards stating:

“This determination does not change the Agency's general policy discussed above that where gases originate in one affected facility and pass through another affected facili ty as part of the manufacturing process, EPA applies the emission limitation or standard for the affected facility from which the gases are discharged directly into the atmosphere. This determination clar ifies that for dry process portland cement plants with an "in-line" ki ln/raw mill configuration, the raw mill does not exist as a separate a ffected facility and; hence, the appropriate emission limit is that which applies to the kiln.”Keith Barnett September 4, 2009 Page 34

Applicability Determination 9600083; “Opacity Limitation for ‘Inline’ Portland Cement Plants,” John B. Rasnic (Sept. 7, 1996).

Just as emissions from the in-line raw mill in Applicability Determination 9600083 were subject to NSPS Subpart F PM mass and opacity limitations for cement kilns, so too would emissions from an in-line coal mill at a cement plant where k iln gases are used to heat and dry the coal be

treated as an extension of the kiln and subject to the Portland Cement NESHAP limits. This approach is consistent with multiple different applicability determinations provided to Ash Grove by EPA stating that kiln exhaust gases are subject to the Po rtland Cement NESHAP regardless of whether they are routed through the co al mill prior to discharge to the atmosphere. See, e.g. Letter from Donald Toensing (EPA Regi on 7) to Roger Behrns (Ash Grove Louisville), September 18, 2002.

The proposed organic HAP standards fail to account for the various volatiles that are added to

the kiln exhaust as a result of contact with the ground coal in a coal mill. There are two configurations of coal mills that employ waste heat. The first, shown in Figure 5, routes kiln exhaust gas through an indirect fired, in-line co al mill and then back out the main stack. The second configuration, shown in Figure 6, routes gas out a separate coal mill stack. Under either configuration, the level of orga nics in the exhaust gases is markedly higher than the sole configuration considered by EPA in establishing the volatile organics standard, i.e., kiln exhaust gas not routed through a coal mill. Ash Grove te sting documents that a considerable quantity of organics are added to the stack exhaust when th e kiln gases are routed through the coal mill. While the majority of the organics are meth ane, the non-methane, non-ethane hydrocarbon, total hydrocarbon emissions exceeded, on average 100 ppm vd. The THC test data that Ash Grove has gathered from its plants is summarized below in Table 4. While the Cha nute kiln is regulated under HWC MACT, the coal mill duct is not influenced by hazardous waste fuels.

Table 4. Coal Mill THC Data

Ash Grove Coal Mill THC Data
Plant Test Date Location THC ppmv (avg) % Volatiles in

Coal

8/31/2005 Coal Mill DuctDry@7%O 2 56.3 36.32

8/19/2008 Coal Mill Duct-Mill OnDry@7%O 2 112.6 36.15 Chanute

8/19/2008 Coal Mill Duct-Mill Off-Dry@7%O 2 43.9 36.15

Durkee 12/9/2005 Coal Mill DuctDry@7%O 2 239.4 39.35

Louisville 10/28-29/2005 Coal Mill DuctDry@7%O 2 189.0 37.42Keith Barnett September 4, 2009 Page 35

In light of these data, a THC standard of 7 ppmvd for existing source s and 6 ppmvd for new sources is grossly inadequate. Ash Grove requests that EPA not revise the organic HAP standard until it has had the opportunity to better evaluate these data and that it include a separate subcategory for kiln exhaust gases passed through an indirect fired, in-line coal mill. In addition, the volatility of the coal being used should be considered in es tablishing standards for in-line coal mills. Consistent with this approach, EPA should also include in the final rule a specific exclusion for coal mills from coverage under the Subpart Y NSPS so that plants are not having to deal with dual, and potentially c onflicting, regulations. Ash Grove ’s most recent comment letter to EPA on the proposed NSPS Subpart Y revisions is attached.

B. Variability Not Properly Acc ounted for in Establishing Floor

Ash Grove believes that EPA has not adequately accounted for variability in establishing the floor for THC and TOHAP. The PCA comments pr ovide extensive detail regarding the need to account for actual variability in establishing the floor and we do not reproduce those data or arguments here. However, Ash Grove adopts by reference those arguments to the maximum extent that they are consistent with the remainder of this letter. We urge EPA to revise the new and existing source THC/TOHAP floors to properly account for variability.

C. Number of Sources in Floor

We believe that EPA erred in establishing the fl oor for the existing source organic HAP standard using data from just two sources. While there are a total of 167 cement kilns in the country, EPA

obtained THC CEMS data for twelve cement kilns. However, EPA chose to only consider two

of the twelve sets of THC data that it obtai ned. Ash Grove believes that this approach to establishing the floor violates the Clean Air Act. EPA provides no legally supportable justification for relying on such a small set of CEMs data to establish the floor.

We believe that the Clean Air Act requires that EPA consider the CEMs data from at least five sources in establishing the exis ting source floor where there ar e 167 affected sources and CEMs data are available from twelve of them. Any ot her interpretation would re sult in the floor being based on an artificially small data set – a resu lt Congress aimed to avoid by mandating that, at the very least, the floor had to consider five sour ces. If EPA’s approach to setting the floor were generally adopted, then it woul d result in the distinction betw een the new source floor and the existing source becoming virtually meaningless—ag ain, an outcome that flies in the face of Congress’ mandate.

There is only one plain language interpretation of the statute and it compels an interpretation consistent with how EPA originally intended to set the THC existing source MACT floor in this rulemaking. Section 112(d)(3) states in relevant part that MACT standards “shall not be less stringent, and may be more st ringent than – (A) the average emission limitation achieved by the best performing 12 percent of the existing source s (for which the Administrator has emissions information)...in the category or subcategory for categories and subcategories with 30 or more sources.” Thus, the term “existi ng sources” at the beginning of subparagraph (A) is modified byKeith Barnett September 4, 2009 Page 36

the phrase “for which the Administrator has emissi ons information.” At the end of the passage, where Congress refers to “categories and subcategor ies with 30 or more sources,” it therefore is

reasonable to read “sources” to mean sources “for which the Administrator has emissions information.” Similarly, “sources” at the end of subparagraph (d)(3)(B) should be modified by the phrase “for which the Administrator has or could reasonably obtain emissions information.”

This plain language comports with the struct ure of the MACT floor provisions, while the interpretation taken by EPA does not. Congress cl early intended that EPA not set the existing source floor based on a very limited data set. Put another way, Congress wanted the existing source floor to be based on repres entative data for the best perfor ming sources. Otherwise, there

would be no reason to ensure that the floor be based on the aver age emission limitation of the top

five sources when the number of sources in th at data set was limited. Congress could have simply required that the floor be based on the average of the top 12 percent in all circumstances

, which, for categories or subcategories of fewer th an 30 sources, would have meant that the floor

would be based on a maximum of four sources. But it chose not to do so. Although there is no legislative history on this choice, it is apparent that Congress did not want the existing source floor “pool” of sources to consist of so few sources . Reading the statute to have “sources” at the end of § 112(d)(3)(A) modified by the phrase “for which the Administrator has emissions information” (and “sources” at the end of § 112( d)(3)(B) modified by the phrase “for which the

Administrator has or could reason ably obtain emissions information” ) steers clear of this result.

This interpretation, which is for ced by the plain language of § 112(d )(3) is consistent with recent EPA pronouncements on the issue. In its 2005 Hazardous Waste Combustor NESHAP, EPA stated that “we are required to use data fr om five sources to co mprise the MACT pool whenever

we have data from fewer than 30 sources ....” 70 Fed. Reg. 59458 (Oct. 12, 2005) (citing § 307(d)(3)(B) (emphasis added). See also th e April 20, 2004 proposal, 69 Fed. Reg. 21230 (“For existing source floors, we identify the best perf ormers as either sources at the 12 percentile ranking and below or the lowest 5 ranked sources values if we have data from less than 30

sources ”) (emphasis added). The Agency made a similar statement in the NESHAP for reinforced plastic composites production: “[W]e received new data that changed the floor for centrifugal casting to 37.5 percent HAP. With less than 30 facilities in the process group for which we have data, the MACT floor must represent the average performance of the top

five facilities .” 68 Fed. Reg. 19390 (April 21, 2003) (emphasis added).

If EPA adopts the new interpretation, the ma ximum number of sources on which the MACT floor for this rulemaking will be based is two sources. If EPA does not establish subcategories for THC in this rulemaking and relies on this new interpretation, the floor will be based on the two top performing sources (12 percent of 12 sour ces is 1.44). This would not comport with Congressional intent to base the existing source floor on a larger set of more representative data.

The situation would be even worse where there are eight or fewer sources, as would be the case for at least one category if EPA decides to subc ategorize for THC. Tw elve percent of eight sources is 0.96. Thus, EPA would consider the emissions data from only one source in setting the existing source MACT floor. This would be an illogical result. We believe that EPA must, at the very least, consider five s ources in establishing the floor.Keith Barnett September 4, 2009 Page 37

D. Compliance Demonstration Method

EPA needs to modify the rule to clarify when testing must be conducted with both the raw mill on and the raw mill off. Under the proposed rule and 1350(h), an existing source complying

with the THC standard would need to install and operate a THC CEM. Compliance with the standard would be computed using the raw data from the CEM and there is no indication as to how the results from a separate coal mill stack would be handled. As written, the presumption is

that the affected source would n eed to conduct two tests, one while the raw mill is on and one while the raw mill is off (see, 40 CFR § 1349(b)(4)( i)). This would make no sense as the coal mill would receive gases directly from the kiln, and would not be affected by the raw mill being on as opposed to the raw mill being off. In addition, as proposed, 40 CFR § 1349(b)(4)(i) indicates that a separate test would need to be conducted on the coal mill stack and that the compliance demonstration would be based on the emissions from the coal mill stack alone. Neither of these requirements app ears to have taken into account th e routing of a slip stream of kiln exhaust gases to a coal mill and then exhaus ting those gases directly to atmosphere. We do not believe that EPA intended a plant with an in-lin e kiln/raw mill to have to test this separate

coal mill stack with the raw mill on and the ra w mill off as such a requirement would be nonsensical. We request that EPA clarify that this is not the case.

EPA also needs to add a formula to enable sour ces to weight the relativ e emission contributions to determine compliance when emissions occur at two points. Many plants with indirect fired, in-line coal mills are designed as in Figure 6 belo w to vent directly to atmosphere. Compliance with the organic HAP standard for a plant so co nfigured should allow the combination of both stacks given that they both constitu te sources of kiln gases. This approach is identical to that which EPA has previously applied to bypass st acks under the PM standard. Therefore, we request that EPA add to the rule a formula equivalent to Equation 2 of 63.1349 whereby an affected source configured such as the one depi cted below can demonstrate compliance with the THC standard by combining the concentrations from the main stack and the coal mill stack.Keith Barnett September 4, 2009 Page 38

Coal

Mill

Kiln Exhaust Gas & Coal

Mill Slipstream w/Separate

Stack Raw Mill 

# Figure 6

Ash Grove also believes that EPA should revise the initial co mpliance demonstration method for the THC standard. Ongoing comp liance with the THC standard, as proposed, is based on a 30 day rolling average. However, the initial compliance demonstration method proposed in 1349(b)(4)(i) is based on the resu lts of a single 24 hour period . Given potential short term variability in the THC emission rate we do not believe that there is a reasonable basis for requiring initial compliance demonstration based on a 24 hour average for a standard that is based on a 30 day rolling average. Therefore, we suggest that EPA revi se 1349(b)(4)(i) to state that the initial compliance demonstration test is based on the average emission rate over the initial a 30 day period.

E. Raw Material Dryers

Ash Grove is concerned that the standards proposed for raw material dryers are not based on any sort of meaningful data. Raw ma terial dryers are separate and di stinct units from kilns. The proposed limit is based on the erroneous assumption that the raw material dryers are similar to kilns as emission sources. However, as the di scussion below documents, this is not the case and so it would be arbitrary to assign the kiln THC limit to raw material dryers without data specific to raw material dryers to suppor t that limit. In the discussion below references made to raw material dryer (dryers) also include raw mills that are not part of an in-line kiln/raw mill system.

The reason that raw material dryers cannot be subject to the same standards as kilns is apparent from the difference in the way that they operate and the way in which they volatilize and oxidize hydrocarbons. The purpose of a kiln is to develop high temperatures for calcining andKeith Barnett September 4, 2009 Page 39

chemically combining the calcium and silica of th e raw materials to manufacture clinker. The temperature at which the dried ra w materials enter the kiln is in excess of 600 degrees F. This temperature quickly volatilizes mo st, if not all, of the hydrocarbons present in the feed. This temperature is also high enough th at a material fraction of the hydrocarbons combust prior to exhausting from the kiln system. As a result, ther e is inherent control of volatiles in a kiln that

results in the low emission rates reflected in the fl oor. By contrast, the pu rpose of a raw material dryer is to remove free water from the raw material s. There is no reason to invest the energy in a raw material dryer to heat the materials substant ially over the boiling point of water. Therefore, raw material dryers are typically operated at less than 400 degrees F. This lower temperature is high enough to volatilize the lighter hydrocarbons in the raw material, but not high enough to

combust those volatiles. As a result of these different operating temperatures, the hydrocarbon emissions profile of a kiln is very differe nt from that of a raw material dryer.

The operational differences between a kiln and a raw material dryer also make it impossible to assign the same standard with the same oxygen correc tion to both classes of units. In a kiln, the main constituents are nitrogen and carbon dioxide. Oxygen levels in the kiln exhaust gas are typically held below 2 percent but due to in-leak age, oxygen content at the kiln stack would be higher, although not higher than 12 percent. By contrast, in a raw material dryer the main constituents are nitrogen and oxygen. Oxygen levels in the exhaust from a raw material dryer would typically be greater than 19 percent. If th e THC concentration in the raw material dryer is adjusted to 7 percent oxygen as proposed for the kiln, the measured THC emission concentrations in the raw material dryer exhaust would have to be less than 1 ppmvd in order to meet the proposed limit of 7 ppmvd after correction to 7 percent oxygen. 12 This is near the reliable precision of the THC anal yzers available for monitoring.

Another factor that makes the comparison betwee n the two sources invalid is the volume of gases passing through the two syst ems. The volume of gases draw n through a kiln system would typically be 5 to 10 times greater than the volume of gases passing through a raw material dryer. Since the THC emissions are expressed as a con centration, the THC emitted from the raw dryer would be greatly exaggerated compared to the em issions from the kiln when processing the same

amount of raw material.

Based on these substantial differences between ki lns and material dryers, there is no basis to simply assign the kiln THC limit (and oxygen correc tion) to material dryers. This would be akin to assigning the same emission standard to a na tural gas fired boiler as to a coal fired boiler because they each combust fossil fuel. Such an ac tion would clearly be arb itrary and capricious. Likewise, EPA must evaluate actua l raw material dryer emissions in order to establish the data necessary to support a regulatory limit for raw mate rial dryers. In the absence of such data collection and analysis, EPA has no basis for imposing the proposed limits.

12 1 ppm THC at 19 percent oxygen equa ls 7.3 ppmvd at 7 percent oxygen.Keith Barnett September 4, 2009 Page 40

IV. Proposed Hydrogen Chloride Standard

Ash Grove supports EPA in retaining the HCl st andard exclusively for major sources and not extending the standard to area so urces. However, Ash Grove ha s concerns regarding the way that the major source standards were devel oped. These concerns are outlined below.

A. Floor Should Not Include “True” Area Sources

Ash Grove is very concerned regarding the source s that were used in establishing the existing source floor. EPA only considered data from 27 kilns and chose the top 4 of those kilns as representative of the 12 percent lowest em itting units. EPA stated in the preamble:

“The top 4 kilns were limited to major sources, and to sources where

we had a minimum of three test runs to allow us to account for variability in setting the floor.” Preamble at 21153.

However, while EPA states that the each of the top four sources are major sources, we understand that the plant with the two kilns with the lowest HCl emission rate (Nos. 1 and 2) and the third lowest emitting plant are all “true” area sources. 13 EPA has emphatically taken the position in the past that the NE SHAP floor should be based on major sources and synthetic minor sources, but not “true” area sources. Fo r example, in the preamble to Semiconductor

NESHAP EPA stated:

“Accordingly, for the proposed rule we used both major sources and synthetic minor sources as the basi s of the MACT floors. We believe our interpretation of section 112(d) of the CAA is correct, and no changes were made for the final rule as a result of these comments.” 68 Fed. Reg. 27918 (May 22, 2003).

This approach was based on the Municipal Solid Waste Landfill NESHAP where EPA had also

concluded that the NESHAP emission limit shoul d be based on major sources and synthetic minor sources, but not on true area sources. 68 Fed. Reg. 2232 (Jan. 16, 2003). Likewise, in establishing the Brick MACT floor s, EPA discussed at great lengt h that major sources are the basis for establishing the floor and that, for pur poses of floor setting, synthetic minor sources constitute major sources. 68 Fed. Reg. 26698 (M ay 16, 2003). All of these discussions are consistent in concluding that true area sources should not be included in the floors. However, the proposed HCl standards in the Portland Cement NESHAP were established based on testing

13 An area source is a source that is not a major s ource. By “true area source,” we mean that the plant did not achieve area source status through the use of a federally enforceable permit limit (i.e., a “true area source” is not a “synthetic minor” source).Keith Barnett September 4, 2009 Page 41

results where three of the four s ources are true area sources. This is contrary to the Clean Air Act as well as established agency precedent.

B. Floor Should Not Include Data Below the Lower Quantification Range

In addition to being true area so urces, the top two sources used to establish the existing source HCl floor should be eliminated as they are be low the lower quantification range for the test method (as proposed). EPA acknowledges that the proposed emission limit as well as much of

the data used to establish that limit are belo w the published detection level of the Method 321

test. Even if one believes that it is appropriate to rely on da ta collected that lie below the published detection level due to concerns that th e level is too high, there is no basis for relying on data that are below the proposed revisions to the Method 321 detection level. EPA is proposing to reduce the detecti on level to “0.1 to 1.0 ppm” Preamble at 21192. However, the top two sources are suggested to have emissions rates of 0.02 ppm. EPA cannot use data to set

the floor that is below the lo wer quantification range for the test method. Therefore, both

because the first two sources are true area sour ces and because the emission rates are below the proposed method detection level, the first two affected source s should be removed from the

floor.

C. Existing Source Floor Should Not Be Based on Just Four Sources

As stated above in relation to the THC standa rds, it would be in di rect contravention of Congressional intent for EPA to establish the HCl floor based solely on four sources. EPA collected stack test data gathered usi ng both Method 321 and 26. We support EPA in eliminating the Method 26 data due to the documen ted low bias of that test method. However, while that means that test data were only availa ble for 27 kilns, that does not mean that EPA should only look at the lowest emitting 12 percen t (4 kilns) of that grouping. CAA §112(d) requires that EPA use the best performing 5 sources or the best performing 12 percent of sources in establishing the MACT floor for situations in which there are 30 or more sources in a category. In this language Congress evidenced a cl ear intent that floors should be established using a minimum number of data points, i.e., at least data from 5 sources.

EPA’s proposed approach for determining the ex isting source floor is c ontrary to prior EPA statements on the issue. As explained above, in the 2005 Hazardous Waste Combustor NESHAP, EPA stated that “we are required to use data from five sources to comprise the MACT pool whenever we have data from fewer than 30 sources ....” 70 Fed. Reg. 59458 (Oct. 12, 2005) (citing § 307(d)(3)(B) (emphasis added). See also the April 20, 2004 proposal, 69 Fed. Reg. 21230 (“For existing source floors, we identify th e best performers as either sources at the 12 percentile ranking and below or th e lowest 5 ranked sources values if we have data from less

than 30 sources ”) (emphasis added). The Agency made a similar statement in the Reinforced Plastic Composite NESHAP: “[W]e received ne w data that changed the floor for centrifugal casting to 37.5 percent HAP. With less than 30 facilities in the process group for which we have data, the MACT floor must represent the average performance of the top five

facilities .” 68 Fed. Reg. 19390 (April 21, 2003) (emphasi s added). EPA cannot diverge fromKeith Barnett September 4, 2009 Page 42

this established means of establishing a MACT floor, particularly when the existing interpretation is clearly consistent with the words of the statute and the new interpretation is not.

The plain language of the statute compels that EPA include at least 5 sources in the existing source floor. Congress clearly intended that EPA not set the existing source floor based on a very limited data set as Congress wanted the ex isting source floor to be based on representative data for the best performing sources. Otherwise, there would be no reason to ensure that the floor be based on the average emission limitation of the top five sources when the number of

sources in that data set was limite d. Congress could have simply re quired that the floor be based on the average of the top 12 percent in all circumstances , which, for categories or subcategories of fewer than 30 sources, would have meant that the floor would be based on a maximum of four

sources. But it chose not to do s o. Although there is no legislative history on this choice, it is apparent that Congress did not wa nt the existing source floor “pool” of sources to consist of so

few sources.

D. Variability Not Properly Acc ounted for in Establishing Floor

Since there is only valid HCl test data for one ma jor source, there is simply not sufficient data

available to calculate a floor for kilns. EPA has proposed an unnecessarily low emission limit for HCl in the incorrect belief that imposing a lo w HCl standard will achieve reductions in SO2 through the installation of scrubbers to control HCl. This is an abuse of the authority to impose standards through the NESHAP process and may not result in reductions in SO2. The previous exemption for the sector from an HCl standard was justified and should remain. However, if a standard were to be imposed not withstanding the paucity of emissi ons data, that standard should

not be lower than the risk threshold level de monstrated by the risk modeling conducted by PCA for the original rulemaking. The kiln with the lowest modeled em ission rate that resulted in a Hazard Index of 1 was 23 ppmvd. Therefore, in no event should the HCl standard be any lower than 23 ppmvd.

Ash Grove believes that EPA has not adequately accounted for variability in establishing the floors generally under the proposed rule and that th is equally affects the proposed HCl standard. The PCA comments provide extensive detail regardi ng the need to account for actual variability in establishing the floors and we do not reproduce those data or arguments here. However, Ash Grove adopts by reference those arguments to the ma ximum extent that they are consistent with the remainder of this letter. We urge EPA to revise the new and existing source floors to properly account for variability for HCl.

E. Table 5 Incorrectly Identifies HC l Emissions From One Ash Grove Source

Ash Grove would like to call EPA’s attention to an error in the da ta in Table 5. Table 5 outlines

the available HCl data for the 27 kilns for whic h Method 321 data were av ailable. Ash Grove’s Durkee plant is identified as s ource #26 on that list with emissi ons of 34.68 ppm HCl. This is not correct. First, as a true area source, the Du rkee plant should not be evaluated as part of setting the floor for the reasons stated above. S econd, the reason that Durkee is an area source isKeith Barnett September 4, 2009 Page 43

that its HCl emission rate is 3.2 ppm (7% O 2 )—an order of magnitude lower than what is stated

in Table 5. Portland cement kilns are not si gnificant sources of HCl. Revising the Durkee emission rate to reflect the correct value underscores this point.

F. EPA Should Subcategorize to Reflect Arid Sources

EPA should create a subcategory under the HCl standard for sour ces that are located in arid regions. As noted above, the Clean Air Act expr essly allows for subcategorization. While many criteria have been evaluated by EPA in exercisi ng its tremendous discretion to subcategorize, clearly the ability to employ a par ticular type of control device is grounds for subcategorization. In most of the preambles quoted above in re lation to subcategorization for mercury, EPA expressly recognized that control device applicabi lity is a reasonable basis for subcategorization. Just recently, EPA reiterated that position in re lation to proposal for mercury emissions from mercury cell chlor-alkali plants.

“Subcategories, or subsets of sim ilar emission sources within a source category, may be defined if tec hnical differences in emissions characteristics, processes, control device applicability , or opportunities for pollution prevention exist within the source category. This policy is supported by section 112(d)(1), the legislative history, our prior rulemakings , and judicial precedent.

“EPA’s broad authority to estab lish categories and subcategories of industry sources is firmly establis hed, and has been recognized as entitled to substantial deference by the U.S. Court of Appeals for the D.C. Circuit and by the U.S. Supreme Court. See, e.g., Davis County Solid Waste Mgmt v. EPA , 101 F.3d 1395, 1405 (DC Cir. 1996) (EPA

has ‘substantial discretion to crea te categories of sources for which standards must be promulgated’); see also Lignite Energy Council v. EPA , 198 F.3d 930, 933 (DC Cir. 1999) (upholding EPA’s refusal to subdivide a category and noting that the Court was ‘[m]indful of the high degree of deference we must s how to EPA’s scientific judgment’ on this question); Chemical Mfrs. Ass’n v. EPA , 470 U.S. 116, 131 (1985) (‘the means used by EPA to define subcategories’ under the Clean Water Act ‘are particularly persuasive cases for deference to the Agency’s interpretation’).” 73 Fed. Reg. 33258, 33273(June 11, 2008) (emphasis added).

This passage documents not only that EPA has rep eatedly considered cont rol device applicability a reasonable basis for subcategorization, but al so notes the considerable deference such a decision will be accorded by the courts.Keith Barnett September 4, 2009 Page 44

EPA cannot reasonably set a standard based on a control technology t ype that cannot be employed in large portion of the western U. S. EPA considered wet scrubbers as a basis for meeting the HCl standard and no consideration wa s given for alternative types of control. However, wet scrubbers are not a viable control technology in va st parts of the western U.S.

where water is not available for use in a scrubber. Given the unavailability of water, we believe that EPA should create a subcategory for arid areas based on those plan ts not having the access to water and so not having the ability to utilize wet scrubbers. Failure to do so would break from well established precedent and arbitrarily imp act plants in one part of the country.

G. EPA Should Clarify that Separately Vented Coal Mill Stacks Need Not Employ HCl CEMs or Separately Demonstrate Compliance

Ash Grove believes that there is no basis for requiring HCl CEMs or other compliance demonstration for coal mills having the configura tion identified in Figure 6, i.e., the coal vents through a dedicated stack rather th an through the main stack. As discussed in relation to THC, indirect fired, in-line coal mills receive their sole source of air and heat from the associated kiln;

these units have no dedicated heat source. Ther efore, consistent with numerous EPA opinions, these units are subject to the kiln exhaust standard s. The proposal requires that for those major sources subject to the HCl standards, either an HCl CEM must be employed or, where a wet scrubber is employed, the affected source may monitor scrubber parameters. There is no basis for concluding that the drying of coal will increase the HCl concentration in the kiln exhaust that is vented through the coal mill. In fact, every su ggestion is that the coal will act much the same as the activated carbon in the ACI system and w ill scrub a portion of the HCl out of the kiln exhaust gas. Because the coal mill will not increase the concentration of HCl in the kiln exhaust (and may even decrease it), and the main st ack will be continuously monitored for HCl concentration, there is no reason to require th e installation and operati on of another HCl CEM on a coal mill stack. Therefore, we request that EPA clarify that where a coal mill vents directly to atmosphere that the coal mill stack is not re quired to install or operate an HCl CEM.

V. Proposed PM Standard

A. EPA Cannot Establish a 112(d) Standard Twice

EPA improperly proposes to establish a revised PM standard based on emission rates that were achieved through compliance with the 1999 Subpart LLL requirements. EPA issued new and existing source PM standards for portland cemen t kilns in 1999. In the proposed rule, EPA stated that it was proposing to amend the 1999 standards “because they do not appear to represent MACT, but rather a level which is achie vable by the bulk of the industry.” Preamble at 21155. Ash Grove disagrees that the 1999 PM standards are not valid NESHAP standards and believes that EPA is acting contrary to the Cl ean Air Act and inconsis tently with previous actions and pronouncements by 1) setting MACT floor s for PM for the second time, and 2) using post-MACT compliance test data as the basis for those floors.Keith Barnett September 4, 2009 Page 45

There is no basis in the Clean Air Act or EPA precedent for establishing a 112(d) standard after existing sources have already enhanced controls to comply with the original standard. Section 112 has a clear two pronged approach with the fi rst step being to establish technology based standards and the second step being to assess those standards based on residual risk. EPA’s proposal to recalculate the floors te n years after its first effort to do so is inconsistent with the agency’s established interpretation of CAA §112( d)(6). For example, in the Coke Oven NESHAP residual risk rulemaking EPA stated:

“The EPA also believes that interp reting section 112(d)(6) as requiring

additional floor determinations c ould effectively convert existing

source standards into new source sta ndards. After 8 years, all sources would be performing at least at the MACT levels of performance, so that the average of the 12 percent of those best performers would be performing at a lower le vel still, probably a pproaching that of new

sources. The EPA sees no indica tion that section 112(d)(6) was intended to have this type of inexor able downward ratcheting effect.” 69 Fed. Reg. 48338, 48351 (Aug. 9, 2004).

This interpretation was upheld by the D.C. Circ uit in reviewing the H azardous Organic NESHAP (HON) residual risk rulemaking when the court noted that there should not be an “inexorable downward ratcheting effect” for the MACT floors. NRDC v. EPA , 529 F.3d 1077, 1083-84 (D.C. Cir. 2008). Many cement kilns upgraded thei r air pollution control equipment in response

to the 1999 rule. The Preamble states that EPA “compiled PM stack test data for 45 kilns from the period 1998 to 2007,” and used the data from the 6 lowest emitting kilns to develop the proposed existing source floor. Pr eamble at 21155. Given that all existing kilns had to comply with the 1999 NESHAP by 2002, EPA proposes to do ju st what the agency and the D.C. Circuit has previously stated was inconsistent with th e Clean Air Act. By basing the new existing source floor levels on these post-co mpliance test data, EPA is propos ing to put in place the same “type of inexorable downward ratcheting effect” th at it has said is inappropriate. This is in

violation of the Clean Air Act.

VI. Ability of Single Source to Comply With All Standards

A. NESHAP As A Whole Must Be Based On Actual Source(s)

Ash Grove is greatly concerned about EPA’s proposal to establish HAP limits based on independent floor evaluations for each pollutant . Section 112(d) of the Clean Air Act requires that EPA set the NESHAP floor for existing sources such that it is not less stringent than "the average emission limitation achieved by the best-per forming 12 percent of the existing sources." Natural Resources Defense Council v. EPA , 489 F.3d 1250, 1254 (D.C. Cir. 2007). In order to comply with section 112(d), EPA must therefore be able to dem onstrate that the suite of limits

that constitute the NESHAP have been achieve d by existing sources. Establishing a NESHAP floor that has never been complied with by the best performing 12 percent of existing sourcesKeith Barnett September 4, 2009 Page 46

clearly contradicts the Act. That is exactly what EPA has proposed to do in that the proposed

NESHAP standards have never been achieved in practice at any individu al source as required by the Clean Air Act. EPA is using a theoretical sour ce in its proposal that is comprised of elements of existing sources, but no actual si ngle existing source. Such an approach contradicts both the plain meaning and the intent of the Clean Air Act. To the extent consistent with the comments in this letter, we adopt and support the PCA comments as to why it vi olates the Act for EPA to use a composite source, rather than a single exis ting source, as the basi s for establishing the

NESHAP limits.

VII. Proposed Startup, Shutdown, Malfunction Requirements

A. NESHAP Cannot Apply During SSM Events Absent Evaluation of SSM Emissions in Floor and Appli cation to Variability Analysis

Ash Grove is greatly concerned about EPA’s pro posed means of addressing the D.C. Circuit’s decision vacating 40 CFR §§ 63.6(f)(1) and 63.6(h)(1 ). Ash Grove believes that it is not appropriate to propose rule revision s before the court has even issu ed the mandate in that case. However, if EPA is going to proceed with rule re visions to replace the incorporation by reference of these provisions, Ash Grove believes that EPA cannot simply state that the standards apply at all times including during times of startup, sh utdown and malfunction (“SSM”). EPA did not incorporate any data reflecting SSM periods into its analysis that re sulted in the standards. Both EPA and the D.C. Circuit have stated on many occas ions that the 12 percent of best controlled sources must be able to comply with the emission standards at all times. This has been the basis for addressing variability in virtually all NESHAP s. If EPA were to apply the standards during SSM periods without having first determined that the best controlled sources can comply during those times, it will have acted arbitrarily and capriciously. Si milarly, if the standards apply during SSM periods the emission ra tes during SSM events must be fully integrated into the variability analysis used to set the standards. There is no indicati on that this was done.

We believe that the best way to address the December 2008 Sierra Club v. EPA decision is to establish separate standards that apply during SSM events. The D. C. Circuit stated that EPA had to establish some 112(d) standard that would apply at all times. However, the D.C. Circuit never implied that the same standard had to apply at all times. We recommend that EPA establish standards that apply during SSM events. We recognize that establishing standards for time periods where emissions cannot reasonably be meas ured is impractical. However, the Clean Air Act provides for this situation. Section 112(h) of the Clean Air Act allows EPA to set work practice standards when it is not practicable to measure emissions. As SSM event are notoriously difficult times to m easure emissions, it would be appr opriate to establish specific work practice standards to be followed during SSM events in lieu of numeric standards.

VIII. Environmental JusticeKeith Barnett September 4, 2009 Page 47

A. Proposed Rule Does Not Fully Access Disproportionate Impacts to Minority and Low-Income Populations

Ash Grove believes that the final rule must be revised as disc ussed above in order to avoid

serious Environmental Justice issues. Execu tive Order 12,898, requires that EPA consider “disproportionately high and adverse human health or environmental effects of [their] programs, policies, and activities on minority populations and low-income populations.” As proposed, these standards have the potenti al to decimate the domestic cement industry and to vastly increase the amount of cement imported from ove rseas producers not subject to such rules.

There are two ways in which these rules coul d result in disproportionately high and adverse effects of on minority and low-income populations. First, EPA identifies two plants as likely having to close if the rule is promulgated as proposed. The populations around these plants rely heavily on the plants for income. Specificall y, the Durkee plant is the major manufacturing employer in the entire county. In additi on, Ash Grove conducted a comprehensive risk assessment showing that the mercury emissions do not result in unacceptable health risks even before controls. Thus the adverse impact of closure would be to the health of the families who depend on this facility for income and health insuran ce. If the plant were to close, the health of the community would be seriously degraded w ith no commensurate improvement related to the

reduced emissions associated with closure as the plant will be well under the acceptable risk thresholds when the controls currently being c onstructed are operationa l. For these reasons, Environmental Justice is triggered domestically by the potential closure. In addition, there are global Environmental Justice issu es. Closure of U.S. cement plants in an era when U.S. production is typically inadequate to meet U.S. needs means that more cement will be imported from overseas. As Asia and India dominate import s to the west coast, th e gap left by California and Oregon plant closures will almo st certainly occur in nations w ith far less stringent controls and significantly higher direct and indirect emissions of crite ria pollutants, HAPs and greenhouse gases. This is particularly relevant in rela tion to mercury and greenhouse gases as these are the most obviously global pollutants. However, offs horing production will also result in localized impacts and so will disproportionate ly impact impoverished areas.

Proceeding without regard to the consequences of domestic closures and offshoring production to less regulated areas would be in direct viol ation of Executive Orde r 12,898. Simply stating that emissions will decrease without assessing the extent to which they will simply move and the impacts of the resulting plant closures is not compliance with Executive Order 12,898. However, EPA can honor Executive Order 12,898 and the Clean Air Act by implementing the revisions suggested in this le tter and maintaining production in the U.S. while also reducing

domestic emissions.

IX. Conclusions

Ash Grove has many concerns regarding the prop osed amendments to Subpart LLL. Ash Grove believes that there are many ways in which EP A can improve its proposed rule while alsoKeith Barnett September 4, 2009 Page 48

improving EPA’s consistency with the Clean Air Act and agency precedent. These concerns, as

discussed in detail above , are summarized below.

A. Mercury Conclusions

• EPA must create a subcategory for the affected sources with ≥ 225 ppb mercury in their

limestone

o EPA precedent, the legislative history and the Williams concurrence in the Brick

MACT decision all support this approach

o For the ≥ 225 ppb subcategory, EPA should esta blish a floor based on the two affected sources and then impose a beyond th e floor requirement that all affected sources within the subcategory must demonstrate compliance by operating endof-pipe controls achieving a 75 percent mi nimum mercury control efficiency and by implementing the following work practices:

 No use of fly ash as an additive in the raw feed

 Implementation of dust shuttling to the maximum extent possible without impacting product quality

 Implementation of a Mercury Minimization Plan to minimize mercury in the raw materials imported from off-site, and

 Implementation of a Control Enhancement Action Plan

• In both subcategories EPA should consider in establishing the floor s the variability of mercury content that is manifest ed in the limestone over time.

• EPA must also better account for actual vari ability, including variability of mercury

attributable to all available fuels.

• EPA must remove the mothballed sources that are currently accounted for in the floor as they do not constitute sources if they are not operating.

• EPA should not include source 1233 in the fl oor as it was manufacturing a specialty cement at the time of sampling that does not accurately reflect operations of the kiln.

o If included in the floor, the limit must refl ect the variability that extends to kiln 1233 manufacturing Type I/II cement (as reflected in the results from the

collocated kiln 1560 which shares the same design and same quarry as kiln 1233)

• , EPA should clarify in the final rule that indi rect fired, in-line coal mills with separate

stacks need not install a CEM and can rely on the compliance certification made for the

main stack.

B. Organic HAP Conclusions

• EPA must revise the organic HAP floors to adequately reflect for the documented variability at cement plants.

• As part of the floor revisions , EPA must include at least fi ve sources in establishing the existing source floor.Keith Barnett September 4, 2009 Page 49

• Indirect fired, in-line coal mills need to have their own separate standard from kilns as the differences in the organics released and the fa te of those organics make the kiln data nonrepresentative of the indirect fired, in-line coal mill emissions.

o If a separate standard is not developed, indirect fired, in-line coal mills with separate stacks must be allowed to use a weighted concentration calculation akin to what is allowed for PM under Subpart LLL.

• Raw material dryers must have a separate standard that is unique to these emission units.

C. HCL Conclusions

• The HCl floors must not include “true” area s ources as this contra dicts established EPA precedent

• EPA must revise the organic HAP floors to adequately reflect for the documented variability at cement plants.

• As part of the floor revisions , EPA must include at least fi ve sources in establishing the existing source floor.

• The floor should not include test data below the lower quantification range.

• EPA must establish an HCl subcategory for affe cted sources in arid parts of the country as wet scrubbers are not an option.

• The Table 5 data need to be revised to re flect the correct emission rate for Source #26 (Durkee) as it overstates emissi ons by one order of magnitude.

• HCl CEMs should not be required for separately vented indirect fired, in-line coal mills.

D. PM Conclusions

• EPA cannot establish a new PM floor using data from sources that have already implemented controls in order to comply with the existing floor.

E. Multi-Pollutant Conclusions

• In order to comply with the plain words of the Clean Air Act the complete suite of proposed NESHAP limits must be achieved in fact at individual sources. EPA cannot based the limits on a hypothetical source.

F. Startup, Shutdown and Malfunction Provisions

• EPA cannot impose the NESHAP limits on affe cted sources during SSM periods unless it documents that the floor sources can comply with the limits during SSM events and it takes into account these periods in establishing variability.

• If EPA is to address SSM events as part of the standard, it should do so by establishing work practice standards, not by applying th e limits that were derived based on normal operations.Keith Barnett September 4, 2009 Page 50

G. Environmental Justice

• EPA is in violation of Executive Orde r 12,898 as it has not fully evaluated the disproportionately high and a dverse human health and envi ronmental effects of the proposed rule on minority and low-income populations.

If you have any questions about these commen ts, please contact me at (913) 319-6065, or curtis.lesslie@ashgrove.com.

Sincerely,

Curtis Lesslie, P.E.

Director of Environmental Affairs Ash Grove Cement Company

Attachment – Ash Grove NSPS Y Comments

cc (via email): Chuck Wiedenhoft (Ash Grove) Fran Streitman (Ash Grove) Peter Tsirigotis (EPA) Steve Silverman (EPA) Andy O’Hare (Portla nd Cement Association) Governor Ted Kulongoski Dick Pedersen (Oregon Dept. of Envir. Quality)11011 C ODY O VERLAND P ARK

, KS 66210

PHONE 913 / 451-8900 FAX 913 /451-1686

CURTIS D

. LESSLIE

, PE

D IRECTOR OF E NVIRONMENTAL A FFAIRS WRITER ’ S DIRECT LINE

– 913/319-6065

J ULY 13, 2009

via electronic mail to a-and-r-docket@epa.gov

Air and Radiation Docket

U.S. EPA

Mail Code 6102T 1200 Pennsylvania Ave., N.W. Washington, DC 20460

Re: Comments on Proposed Subpart Y NSPS Revisions Docket ID No.EPA-HQ-OAR-2008-0260

Dear Ms. Johnson:

Ash Grove Cement Company (Ash Grove) is writing to offer comments on the May 27, 2009 proposed revisions to the Subpart Y standa rds of performance for new and modified coal preparation plants (the “Supplemental Proposal”). The origin al Subpart Y proposal was published on April 28, 2008 (73 Fed. Reg. 22901), but differed markedly from the Supplemental Proposal. Although these commen ts are specific to the Supplemental Proposal, our proposed approach woul d apply equally to both proposals.

Ash Grove is an American owned business he adquartered in Overland Park, Kansas. Ash Grove is the fifth largest cement manufacturer in the United States with cement plants in

nine states across the countr y. A pioneer of the limestone and cement industries, the Company was incorporated in Missouri in 1882 and has been majority owned and controlled by the Sunderland family since 1913. The nine cement plants operating in the Ash Grove system are some of the most en ergy efficient and best maintained in the country and have an annual production capacity of more than 8.0 m illion tons of cement. The quality portland and masonry cements pr oduced at these plants are used in the construction of highways, bri dges, commercial and industr ial complexes, residential homes, and a myriad of other structures.

Ash Grove is potentially directly affected by the proposed amendments to the Subpart Y NSPS because several of our plants operate facili ties that utilize waste heat from our kilnsEPA Air & Radiation Docket (6102T) July 13, 2009

to dry coal prior to it being stored and subs equently introduced into burners where it is

combusted. These in-line coal mills do not exist as separate facilities and have no independent means of generating heat and so do not function in the absence of receiving

waste heat from the kiln. If these in-line co al mills are considered within the Subpart Y definition of “coal preparation plant,” then new, modified and reconstructed coal mills at portland cement plants would be affected facilities.

Ash Grove urges EPA to explicitly exempt portland cement plants from Subpart Y in recognition of longstanding agency guidance rega rding interdependent facilities. Figure 1 shows a common configuration of coal mills in energy efficient portland cement plants. In this configuration, a fracti on of the exhaust gas from a k iln is routed through the coal mill to dry the fuel prior to storage and subsequent combustion in the kiln or calciner.

The exhaust is then either vent ed to a dedicated stack or retu rned to the main kiln stack where it is commingled with the kiln exhaust resulting in a gas stream that contains both the characteristics of a cement kiln and a coal mill. This design is energy efficient in that it allows the coal to be dried exclusively with waste heat (there is no back-up heat source and if the kiln is not operating, the in-line coal mill cannot operate). However, this design results in a gas stream having pollutant characteristics unlike a conventional coal mill. Therefore, we believe that coal mills configured such as this should be addressed under the Subpart F NSPS and/or Subpart LLL NE SHAP rather than under Subpart Y as EPA has not had the benefit of data related to cement kiln in-line coal mills in setting the

standards.

Coal

Mill

Kiln Exhaust Gas & Coal

Mill Slipstream Raw Mill 

# Figure 1

EPA guidance dating from the mid-1990s woul d not consider cement plant in-line coal mills subject to Subpart Y. Similar issues ha ve arisen in the past in relation to cement plant equipment. Just as a portion of the hot process exhaust gas is routed to the coal mill Note: Coal mill may discharge directly to atmosphere through a dedicated stack, or to the main

stack as de p icted.EPA Air & Radiation Docket (6102T) July 13, 2009

in many modern cement plants, a portion of th e exhaust gas is also used to preheat the raw feed introduced into the kiln. This type of device is referred to as an “in-line raw mill” as the raw mill (just like an in-line coal mill) is completely dependent on the kiln for all of its heat input. In a 1995 determin ation, EPA stated that when “gases originate in one affected facility and pass through a nother affected facility as part of the manufacturing process, EPA applies the standard for the affected faci lity from which the gases are discharged directly into the atmo sphere.” Applicability Determination 9600082 “Alternative Monitoring and Opacity Limit Clarification for San Juan Cement Company,” John B. Rasnic (May 12, 1995). However, a year later EPA qualified this guidance when it concluded that an in-line raw mill was subject to the Subpart F kiln standards stating:

This determination does not ch ange the Agency's general policy discussed above that where gases originate in one affected facility and pass through another affected facility as part of the manufacturing pro cess, EPA applies the emission limitation or standard for the affected facility from which the gases are discharged directly into the atmosphere. This

determination clarifies that for dry process portland cement plants with an "in-line" kiln/raw mill configuration, the raw mill does not exist as a separate affected facility and; hence, the appropriate emission limit is that which applies to the kiln.

Applicability Determination 9600083; “Opacity Limitation for ‘In-lin e’ Portland Cement Plants,” John B. Rasnic (Sept. 7, 1996). Just as emissions from the in-line raw mill in Applicability Determination 9600083 were subject to NSPS Subpart F PM mass and opacity limitations for cement kilns, so too should emissions from an in-line coal mill at a cement plant where kiln gases are used to heat and dry the coal be treated as an extension of the kiln and subject to Subpart F NSPS and Subpart LLL NESHAP cement kiln PM and opacity limits. This approach is consis tent with multiple different applicability determinations provided to Ash Grove by EPA st ating that kiln exhaust gases are subject to the portland cement NESHAP (LLL) regardless of whether they are routed through the coal mill prior to discharge to the atmosphe re. See, e.g. Letter from Donald Toensing (EPA Region 7) to Roger Behrns (Ash Grove Louisville), September 18, 2002. It is also

consistent with the data that EPA has revi ewed in establishing the proposed Subpart Y limits. In the absence of data related to emissions from in-line coal mills, EPA would not have a rational basis supported by evidence in the record for es tablishing limits that apply to these unique gas streams.

Although the guidance is clear that in-line coal mills should not be subject to the Subpart Y NSPS, the Supplemental Proposal does not pr ovide any clarification, either in the preamble or in the proposed amendments to th e Subpart Y NSPS, of the applicability of the thermal dryer standards to portland cement plant in-line coal mills. Ash Grove respectfully requests that EP A clarify that the Subpart Y NSPS does not apply to an inline coal mill at a portland cement plant. The unique coal processing and handlingEPA Air & Radiation Docket (6102T) July 13, 2009

systems found at portland cement plants are best addressed by the portland cement NSPS (Subpart F) and NESHAP (Subpart LLL).

Ash Grove appreciates the opportunity to comment on the Supplemental Proposal. We

believe that it is consistent with well esta blished EPA guidance that in-line coal mills located at portland cement plants should not be subject to Subpart Y. In order to more specifically address the unique nature of cement plants, Subpart Y should exempt portland cement plants. Appropriate standa rds for these facilities can and are being developed under the amendments to Subpart F NSPS and the Subpart LLL NESHAP. If you have any questions about these comment s, please contact me at (913) 319-6065, or curtis.lesslie@ashgrove.com.

Sincerely,

Curtis D. Lesslie, P.E.

Director of Environmental Affairs Ash Grove Cement Company