[6560-50-P]

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2002-0051; FRL- ]

RIN 2060-AO15

National Emission Standards for Hazardous Air Pollutants From 

the Portland Cement Manufacturing Industry

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

SUMMARY: EPA is proposing amendments to the current National 

Emission Standards for Hazardous Air Pollutants (NESHAP) from 

the Portland Cement Manufacturing Industry. These proposed 

amendments would add or revise, as applicable, emission limits 

for mercury, total hydrocarbons (THC), and particulate matter 

(PM) from kilns and in-line kiln/raw mills located at a major or 

an area source, and hydrochloric acid (HCl) from kilns and inline kiln/raw mills located at major sources. These proposed 

amendments also would remove four provisions in the current 

regulation: the operating limit for the average hourly recycle 

rate for cement kiln dust, and the requirement that cement kilns 

only use certain type of utility boiler fly ash. They would 

also remove the opacity limits for kilns and clinker coolers and 

the 50 parts per million volume dry (ppmvd) THC emission limit 

for new greenfield sources. 
2

DATES: Comments must be received on or before [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. If any 

one contacts EPA by [INSERT DATE 10 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] requesting to speak at a 

public hearing, EPA will hold a public hearing on [INSERT DATE 

15 DAYS AFTER PUBLICATION OF THIS PROPOSED RULE IN THE FEDERAL 

REGISTER]. Under the Paperwork Reduction Act, comments on the 

information collection provisions are best assured of having 

full effect if the Office of Management and Budget (OMB) 

receives a copy of your comments on or before [INSERT DATE 30 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

ADDRESSES: Submit your comments, identified by Docket ID No. 

EPA-HQ-OAR-2002-0051, by one of the following methods: 

• http://www.regulations.gov: Follow the on-line 

instructions for submitting comments.

• E-mail: a-and-r-docket@epa.gov. 

• Fax: (202) 566-9744.

• Mail: U.S. Postal Service, send comments to: EPA 

Docket Center (6102T), National Emission Standards for 

Hazardous Air Pollutant From the Portland Cement 

Manufacturing Industry Docket, Docket ID No. EPA-HQOAR-2002-0051, 1200 Pennsylvania Ave., NW, Washington, 

DC 20460. Please include a total of two copies. In 

addition, please mail a copy of your comments on the 
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information collection provisions to the Office of 

Information and Regulatory Affairs, Office of 

Management and Budget (OMB), Attn: Desk Officer for 

EPA, 725 17th St., NW, Washington, DC 20503.

• Hand Delivery: In person or by courier, deliver 

comments to: EPA Docket Center (6102T), Standards of 

Performance (NSPS) for Portland Cement Plants Docket, 

Docket ID No. EPA-HQ-OAR-2007-0877, EPA West, Room 

3334, 1301 Constitution Avenue, NW, Washington, DC 

20004. Such deliveries are only accepted during the 

Docket’s normal hours of operation, and special 

arrangements should be made for deliveries of boxed 

information. Please include a total of two copies.

Instructions: Direct your comments to Docket ID No. EPAHQ-OAR-2002-0051. EPA’s policy is that all comments received 

will be included in the public docket without change and may be 

made available online at www.regulations.gov, including any 

personal information provided, unless the comment includes 

information claimed to be Confidential Business Information 

(CBI) or other information whose disclosure is restricted by 

statute. Do not submit information that you consider to be CBI 

or otherwise protected through www.regulations.gov or e-mail. 

The www.regulations.gov website is an “anonymous access” system, 

which means EPA will not know your identity or contact 
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information unless you provide it in the body of your comment. 

If you send an e-mail comment directly to EPA without going 

through www.regulations.gov, your e-mail address will be 

automatically captured and included as part of the comment that 

is placed in the public docket and made available on the 

Internet. If you submit an electronic comment, EPA recommends 

that you include your name and other contact information in the 

body of your comment and with any disk or CD-ROM you submit. If 

EPA cannot read your comment due to technical difficulties and 

cannot contact you for clarification, EPA may not be able to 

consider your comment. Electronic files should avoid the use of 

special characters, any form of encryption, and be free of any 

defects or viruses.

Docket: All documents in the docket are listed in the 

www.regulations.gov index. Although listed in the index, some 

information is not publicly available, e.g., CBI or other 

information whose disclosure is restricted by statute. Certain 

other material, such as copyrighted material, will be publicly 

available only in hard copy. Publicly available docket 

materials are available either electronically in 

www.regulations.gov or in hard copy at the EPA Docket Center, 

National Emission Standards for Hazardous Air Pollutants from 

the Portland Cement Manufacturing Industry Docket, EPA West, 

Room 3334, 1301 Constitution Ave., NW, Washington, DC. The 
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Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday 

through Friday, excluding legal holidays. The telephone number 

for the Public Reading Room is (202) 566-1744, and the telephone 

number for the Docket Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Mr. Keith Barnett, Office of 

Air Quality Planning and Standards, Sector Policies and Programs 

Division, Metals and Minerals Group (D243-02), Environmental 

Protection Agency, Research Triangle Park, NC 27711, telephone 

number: (919) 541-5605; fax number: (919) 541-5450; e-mail 

address: barnett.keith@epa.gov.

SUPPLEMENTARY INFORMATION:

The information presented in this preamble is organized as 

follows:

I. General Information

A. Does this action apply to me?

B. What should I consider as I prepare my comments to EPA?

C. Where can I get a copy of this document?

D. When would a public hearing occur?

II. Background Information

A. What is the statutory authority for these proposed 

amendments?

B. Summary of the National Lime Association v. EPA Litigation

C. EPA’s Response to the Remand

D. Reconsideration of EPA Final Action in Response to the

Remand

III. Summary of Proposed Amendments to Subpart LLL

A. Emissions Limits

B. Operating Limits

C. Testing and Monitoring Requirements

IV. Rationale for Proposed Amendments to Subpart LLL

A. MACT Floor Determination Procedure for all Pollutants

B. Determination of MACT for Mercury Emissions from Major and 

Area Sources
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C. Determination of MACT for THC Emissions from Major and Area

Sources

D. Determination of MACT for HCl Emissions from Major Sources

E. Determination of MACT for PM Emissions from Major and Area 

Sources

F. Selection of Compliance Provisions

G. Selection of Compliance Dates

H. Discussion of EPA’s Sector Based Approach for Cement 

Manufacturing

I. Other Changes and Areas Where We are Requesting Comment

V. Summary of Comments and Responses on Notice of

Reconsideration and EPA Final Action in Response to Remand

A. Petition to Withdraw Final Standards

B. Petition to Reconsider Final Standards

C. New Source MACT for Mercury Emissions and Related 

Requirements

D. New Source MACT for THC Emissions and Related

Requirements

E. Cement Kiln Dust Requirements

F. Fly Ash Requirements

G. Compliance Dates for Cement Kiln Dust and Fly Ash Provisions

H. Research and Technology

VI. Summary of Cost, Environmental, Energy, and Economic 

Impacts of Proposed Amendments

A. What are the affected sources?

B. How are the impacts for this proposal evaluated?

C. What are the air quality impacts?

D. What are the water quality impacts?

E. What are the solid waste impacts?

F. What are the secondary impacts?

G. What are the energy impacts?

H. What are the cost impacts?

I. What are the economic impacts?

J. What are the benefits?

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination 

with Indian Tribal Governments

G. Executive Order 13045: Protection of Children from 

Environmental Health Risks and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations 

That Significantly Affect Energy Supply, Distribution, or 

Use
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I. National Technology Transfer Advancement Act

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and LowIncome Populations

I. General Information

A. Does this action apply to me?

Categories and entities potentially regulated by this 

proposed rule include: 

Category NAICS 

code1

Examples of regulated entities

Industry.... 327310 Portland cement plants

Federal government... Not affected.

State/local/tribal 

government...

Portland cement Plants

1 North American Industry Classification System.

This table is not intended to be exhaustive, but rather 

provides a guide for readers regarding entities likely to be 

regulated by this action. To determine whether your facility 

would be regulated by this proposed action, you should examine 

the applicability criteria in 40 CFR 63.1340 (subpart LLL). If 

you have any questions regarding the applicability of this 

proposed action to a particular entity, contact the person 

listed in the preceding FOR FURTHER INFORMATION CONTACT section.

B. What should I consider as I prepare my comments to EPA?

Do not submit information containing CBI to EPA through 

www.regulations.gov or e-mail. Send or deliver information 
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identified as CBI only to the following address: Roberto 

Morales, OAQPS Document Control Officer (C404-02), Office of Air 

Quality Planning and Standards, Environmental Protection Agency, 

Research Triangle Park, NC 27711, Attention Docket ID No. EPAHQ-OAR-2002-0051. Clearly mark the part or all of the 

information that you claim to be CBI. For CBI information in a 

disk or CD-ROM that you mail to EPA, mark the outside of the 

disk or CD-ROM as CBI and then identify electronically within 

the disk or CD-ROM the specific information that is claimed as 

CBI. In addition to one complete version of the comment that 

includes information claimed as CBI, a copy of the comment that 

does not contain the information claimed as CBI must be 

submitted for inclusion in the public docket. Information so 

marked will not be disclosed except in accordance with 

procedures set forth in 40 CFR part 2.

C. Where can I get a copy of this document?

In addition to being available in the docket, an electronic 

copy of this proposed action is available on the Worldwide Web 

(WWW) through the Technology Transfer Network (TTN). Following 

signature, a copy of this proposed action will be posted on the 

TTN’s policy and guidance page for newly proposed or promulgated 

rules at http://www.epa.gov/ttn/oarpg. The TTN provides 

information and technology exchange in various areas of air 

pollution control.
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D. When would a public hearing occur?

If anyone contacts EPA requesting to speak at a public

hearing by [INSERT DATE 10 DAYS AFTER DATE OF PUBLICATION IN THE 

FEDERAL REGISTER], a public hearing will be held on [INSERT DATE 

15 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. 

Persons interested in presenting oral testimony or inquiring as 

to whether a public hearing is to be held should contact Mr. 

Keith Barnett, listed in the FOR FURTHER INFORMATION CONTACT

section, at least 2 days in advance of the hearing.

II. Background Information

A. What is the statutory authority for these proposed

amendments?

Section 112(d) of the Clean Air Act (CAA) requires EPA to 

set emissions standards for Hazardous Air Pollutants (HAP) 

emitted by major stationary sources based on performance of the 

maximum achievable control technology (MACT). The MACT 

standards for existing sources must be at least as stringent as 

the average emissions limitation achieved by the best performing

12 percent of existing sources or the best performing 5 sources 

for source categories with less than 30 sources (CAA section 

112(d)(3)(A) and (B)). This level of minimum stringency is 

called the MACT floor. For new sources, MACT standards must be 

at least as stringent as the control level achieved in practice 

by the best controlled similar source (CAA section 112(d)(3)). 
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EPA also must consider more stringent "beyond-the-floor" control 

options. When considering beyond-the-floor options, EPA must 

consider not only the maximum degree of reduction in emissions 

of HAP, but must take into account costs, energy, and nonair 

environmental impacts when doing so.

Section 112(k)(3)(B) of the CAA requires EPA to identify at 

least 30 HAP that pose the greatest potential health threat in 

urban areas, and section 112(c)(3) requires EPA to regulate,

under section 112(d) standards, the area source1 categories that 

represent 90 percent of the emissions of the 30 “listed” HAP 

(“urban HAP”). We implemented these listing requirements 

through the Integrated Urban Air Toxics Strategy (64 FR 38715, 

July 19, 1999).2

The portland cement source category was listed as a source 

category for regulation under this 1999 Strategy based on 

emissions of arsenic, cadmium, beryllium, lead, and 

polychlorinated biphenyls. The final NESHAP for the Portland 

Cement Manufacturing Industry (64 FR 31898, June 14, 1999) 

included emission limits based on performance of MACT for the 

control of THC emissions from area sources. This rule fulfills 

 

1 An area source is a stationary source of HAP emissions that is 

not a major source. A major source is a stationary source that 

emits or has the potential to emit 10 tons per year (tpy) or 

more of any HAP or 25 tpy or more of any combination of HAP.

2 Since its publication in the Integrated Urban Air Toxics 

Strategy in 1999, EPA has amended the area source category list 

several times.
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the requirement to regulate area source cement kiln emissions of 

polychlorinated biphenyls (for which THC is a surrogate). 

However, EPA did not include requirements for the control of the 

non-volatile metal HAP (arsenic, cadmium, beryllium, and lead) 

from area sources in the 1999 rule or in the 2006 amendments. 

To fulfill our requirements under section 112(k), EPA is 

proposing to regulate emissions of these metal HAP from portland 

cement manufacturing facilities that are area sources (using 

particulate matter as a surrogate). In this proposal, EPA is 

proposing PM standards for area sources based on performance of 

MACT. 

Section 112(c)(6) requires EPA to list, and to regulate 

under standards established pursuant to section 112(d)(2) or 

(d)(4), categories of sources accounting for not less than 90 

percent of emissions of each of seven specific HAP: alkylated 

lead compounds; polycyclic organic matter; hexachlorobenzene; 

mercury; polychlorinated byphenyls; 2,3,7,8-

tetrachlorodibenzofurans; and 2,3,7,8-tetrachloroidibenzo-pdioxin. Standards established under CAA 112(d)(2) must reflect 

the performance of MACT. “Portland cement manufacturing: nonhazardous waste kilns” is listed as a source category for 

regulation under section 112(d)(2) pursuant to the section 

112(c)(6) requirements due to emissions of polycyclic organic 

matter, mercury, and dioxin/furans (63 FR 17838, 17848, April 
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10, 1998); see also 63 FR at 14193 (March 24, 1998) (area source 

cement kilns’ emissions of mercury, dibenzo-p-dioxins and 

dibenzo-p-furans, polycyclic organic matter, and polychlorinated 

biphenyls are subject to MACT).

B. Summary of the National Lime Association v. EPA Litigation

On June 14, 1999 (64 FR 31898), EPA issued the NESHAP for 

the Portland Cement Manufacturing Industry (40 CFR part 63, 

subpart LLL).5 The 1999 final rule established emission 

limitations for PM as a surrogate for non-volatile HAP metals

(major sources only), dioxins/furans, and for greenfield6 new 

sources total THC as a surrogate for organic HAP. These 

standards were intended to be based on the performance of MACT 

pursuant to sections 112 (d)(2) and (3). We did not establish 

limits for THC for existing sources and non-greenfield new 

sources, nor for HCl or mercury for new or existing sources. We 

reasoned that emissions of these constituents were a function of 

raw material concentrations and so were essentially 

uncontrolled, the result being that there was no level of 

 

5 Cement kilns which burn hazardous waste are a separate source 

category, since their emissions of many HAP differ from portland 

cement kilns’ as a result of the hazardous waste inputs. Rules 

for hazardous waste-burning cement kilns are found at subpart 

EEE of part 63.

6 For purposes of the 1999 rule, a new greenfield kiln is a kiln 

constructed after March 24, 1998, at a site where there are no 

existing kilns. 
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performance on which a floor could be based. EPA further found 

that beyond the floor standards for these HAP were not 

warranted. 

Ruling on petitions for review of various environmental 

groups, the D.C. Circuit held that EPA had erred in failing to 

establish section 112 (d) standards for mercury, THC (except for 

greenfield new sources) and hydrochloric acid. The court held 

that”[n]othing in the statute even suggests that EPA may set 

emission levels only for those ... HAPs controlled with 

technology.” National Lime Ass’n v. EPA, 233 F. 3d 625, 633 

(D.C. Cir. 2000). The court also stated that EPA is obligated 

to consider other pollution–reducing measures such as process 

changes and material substitution. Id. at 634. Later cases go 

on to hold that EPA must account for levels of HAP in raw 

materials and other inputs in establishing MACT floors, and 

further hold that sources with low HAP emission levels due to 

low levels of HAP in their raw materials can be considered best 

performers for purposes of establishing MACT floors. See, e.g., 

Sierra Club v. EPA (Brick MACT), 479 F. 3d 875, 882-83 

(D.C. Cir. 2007).7 

 

7 In the remainder of the opinion, the court in National Lime 

Ass’n upheld EPA’s standards for particulate matter and dioxin 

(on grounds that petitioner had not properly raised arguments in 

its opening brief), upheld EPA’s use of particulate matter as a 

surrogate for HAP metals, and remanded for further explanation 

EPA’s choice of an analytic method for hydrochloric acid.
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C. EPA’s Response to the Remand 

 In response to the National Lime Ass’n mandate, on December 

2, 2005, we proposed standards for mercury, THC, and HCl. (More 

information on the regulatory and litigation history may be 

found at 70 FR 72332, December 2, 2005.) We received over 1,700 

comments on the proposed amendments. Most of these comments 

addressed the lack of a mercury emission limitation in the 

proposed amendments. On December 20, 2006 (71 FR 76518), EPA 

published final amendments to the national emission standards 

for these HAP. The final amendments contain a new source 

standard for mercury emissions from cement kilns and kilns/inline raw mills of 41 micrograms per dry standard cubic meter, or 

alternatively the application of a limestone wet scrubber with a 

liquid-to-gas ratio of 30 gallons per 1,000 actual cubic feet 

per minute of exhaust gas. The final rule also adopted a 

standard for new and existing sources banning the use of utility 

boiler fly ash in cement kilns where the fly ash mercury content 

has been increased through the use of activated carbon or any 

other sorbent unless the cement kiln seeking to use the fly ash 

can demonstrate that the use of fly ash will not result in an 

increase in mercury emissions over its baseline mercury 

emissions (i.e., emissions not using the mercury-laden fly ash). 

EPA also issued a THC standard for new cement kilns (except for 

greenfield cement kilns that commenced construction on or before 
15

December 2, 2005) of 20 parts per million (corrected to 7 

percent oxygen) or 98 percent reduction in THC emissions from 

uncontrolled levels. EPA did not set a standard for HCl, 

determining that HCl was a pollutant for which a threshold had 

been established, and that no cement kiln, even under worst case 

operating conditions and exposure assumptions, would emit HCl at 

levels that would exceed that threshold level, allowing for an 

ample margin of safety. 

D. Reconsideration of EPA Final Action in Response to the 

Remand 

At the same time we issued the final amendments, EPA itself 

determined to reconsider the new source standard for mercury, 

the existing and new source standard banning cement kiln use of 

certain mercury-containing fly ash, and the new source standard 

for THC (71 FR 76553, December 20, 2006). EPA granted 

reconsideration of the new source mercury standard both due to 

substantive issues relating to the performance of wet scrubbers 

and because information about their performance in the industry 

had not been available for public comment. We also committed to 

undertake a test program for mercury emissions from cement kilns 

equipped with wet scrubbers that would enable us to resolve 

these issues. We further explained that we were granting 

reconsideration of the work practice requirement banning the use 

of certain mercury-containing fly ash in cement kilns to allow 
16

further opportunity for comment on both the standard and the 

underlying rationale and because we did not feel we had the 

level of analysis we would like to support a beyond-the-floor 

determination. We granted reconsideration of the new source 

standard for THC because the information on which the standard 

was based arose after the period for public comment. We 

requested comment on the actual standard, whether the standard 

is appropriate for reconstructed new sources (if any should 

occur) and the information on which the standard is based. We

specifically solicited data on THC emission levels from 

preheater/precalciner cement kilns. We stated that we would 

evaluate all data and comments received, and determine whether 

in light of those data and comments it is appropriate to amend 

the promulgated standards. 

EPA received comments on the notice of reconsideration from 

cement plants, energy companies, industry associations, a 

technical consultant, one State, one environmental group, and 

one private citizen. As part of these comments, one industry 

trade association submitted a petition to withdraw the new 

source MACT standards for mercury and THC and one environmental 

group submitted a petition for reconsideration of the 2006 final 

action. We have carefully considered these comments in the 

development of these proposed amendments. Section V of this 
17

preamble summarizes the comments on the notice of 

reconsideration and EPA’s responses.

In addition to the reconsideration discussed above, EPA 

received a petition from Sierra Club requesting reconsideration 

of the existing source standards for THC, mercury, and HCl, and 

judicial petitions for review challenging the final amendments. 

EPA granted the reconsideration petition. The judicial 

petitions have been combined and are being held in abeyance 

pending the results of the reconsideration.

In March 2007 the D.C. Circuit court issued an opinion 

(Sierra Club v. EPA, 479 F.3d 875 (D.C. Cir. 2007)(Brick MACT)) 

vacating and remanding section 112(d) MACT standards for the 

Brick and Structural Clay Ceramics source categories. Some of 

the key holdings in that case were:

 Floors for existing sources must reflect the average

emission limitation achieved by the best performing 12 

percent of existing sources, not levels EPA considers to be 

achievable by all sources;

 EPA cannot set floors of “no control.” The Court 

reiterated its prior holdings, including National Lime 

Ass’n, confirming that EPA must set floor standards for all 

HAP emitted by the major source, including those HAP that 

are not controlled by at-the-stack control devices
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 EPA cannot ignore non-technology factors that reduce HAP 

emissions. Specifically, the Court held that “EPA’s 

decision to base floors exclusively on technology even 

though non-technology factors affect emissions violates the 

Act.” 

Based on the Brick MACT decision, we believe a source’s 

performance resulting from the presence or absence of HAP in raw 

materials must be accounted for in establishing floors; i.e., a 

low emitter due to low HAP proprietary raw materials can still 

be a best performer. In addition, the fact that a specific 

level of performance is unintended is not a legal basis for 

excluding the source’s performance from consideration. National 

Lime Ass’n, 233 F. 3d at 640.

The Brick MACT decision also stated that EPA may account 

for variability in setting floors. However, the court found 

that EPA erred in assessing variability because it relied on 

data from the worst performers to estimate best performers’ 

variability, and held that “EPA may not use emission levels of 

the worst performers to estimate variability of the best 

performers without a demonstrated relationship between the two.” 

479 F. 3d at 882.

The majority opinion in the Brick MACT case does not 

address the possibility of subcategorization to address 

differences in the HAP content of raw materials. However, Judge 
19

William’s concurrence opined that EPA’s ability to create 

subcategories for sources of different classes, size, or type 

(section 112 (d)(1)) may provide a means out of the seeming 

paradox of floor standards being achieved in practice yet be 

unachievable where they reflect differences in raw material HAP 

levels to which other sources may lack access. Id.at 884-85.9

After considering the implications of this decision, EPA 

granted the petition for reconsideration of all the existing 

source standards in the 2006 rulemaking.

A second court opinion is also relevant to this proposal. 

In Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008) the court 

vacated the regulations contained in the General Provisions 

which exempt major sources from MACT standards during periods of 

startup, shutdown and malfunction (SSM)). The regulations (in 

40 C.F.R. 63.6(f)(1) and 63.6(h)(1)) provided that sources need 

not comply with the relevant section 112(d) standard during SSM 

events and instead must “minimize emissions . . . to the 

 

9 “What if meeting the ‘floors’ is extremely or even 

prohibitively costly for particular plants because of conditions 

specific to those plants (e.g., adoption of the necessary 

technology requires very costly retrofitting, or the required 

technology cannot, given local inputs whose use is essential, 

achieve the ‘floor’)? For these plants, it would seem that what 

has been ‘achieved’ under § 112(d)(3) would not be ‘achievable’ 

under § 112(d)(2) in light of the latter's mandate to EPA to 

consider cost. ...[O]ne legitimate basis for creating additional 

subcategories must be the interest in keeping the relation 

between ‘achieved’ and ‘achievable’ in accord with common sense 

and the reasonable meaning of the statute. “
20

greatest extent which is consistent with safety and good air 

pollution control practices.” The Portland Cement NESHAP does 

not contain specific provisions covering operation during SSM 

operating modes; rather it references the now-vacated rules in 

the General Provisions. As a result of the court decision

vacating those general provisions, we are required to address

them in this rulemaking. Discussion of this issue may be found 

in Section IV.G.

III. Summary of Proposed Amendments to Subpart LLL

This section presents the proposed amendments to the 

Portland Cement NESHAP. In the section presenting the amended 

rule language, there is some language that it not amendatory, 

but is presented for the reader’s convenience. We are not 

reopening or otherwise considering unchanged rule language 

presented for the reader’s convenience, and will not accept 

comments on such language. 

A. Emissions Limits

We are proposing the following new emission limits in this 

action.

Kilns and In-line Kiln/Raw mills

Mercury. For cement kilns or in-line kilns/raw mills an 

emissions limit of 43 lb/million(MM) tons clinker for existing 
21

sources and 14 lb/MM tons clinker for new sources. Both 

proposed limits are based on an averaging period of 30 days.

THC. For cement kilns or in-line kilns/raw mills an 

emissions limit of 7 parts per million by volume (ppmv) for 

existing sources and 6 ppmvd for new sources, measured dry as 

propane and corrected to 7 percent oxygen, measured on a 30 day 

average in each case. Because the proposed existing source 

standard would be more stringent than the new source standard of 

50 ppmv contained in the 1999 final rule for greenfield new 

sources, we are also proposing to remove the 50 ppmv standard.

As an alternative to the THC standard, we are proposing 

that the cement kilns or in-line kilns/raw mills can meet a 

standard of 2 ppmv total combined organic HAP for existing 

sources or 1 ppmv total organic HAP combined for new sources, 

measured dry and corrected to 7 percent oxygen. The alternative 

standard would be based on organic HAP emission testing that 

would establish a site specific THC limit that would demonstrate 

compliance with the total organic HAP limit. The site specific 

THC limit would be measured as a 30 day rolling average. 

PM. For cement kilns or cement kilns/in-line raw mills an 

emissions limit of 0.085 pounds per ton (lb/ton) clinker for 

existing sources and 0.080 lb/tons clinker for new sources. 

Kilns and kiln/in-line raw mills where the clinker cooler gas is 

combined with the kiln exhaust and sent to a single control 
22

device for energy efficiency purposes (i.e., to extract heat 

from the clinker cooler exhaust) would be allowed to adjust the 

PM standard upward based on the relative gas flows from the kiln 

and the clinker cooler exhaust.

Opacity. We are proposing to remove all opacity standards 

for kilns and clinker coolers because these sources will be 

required to monitor compliance with the PM emissions limits by 

more accurate means. 

Hydrochloric Acid. For cement kilns or cement kilns/inline raw mills an emissions limit of 2 ppmv for existing sources 

and 0.1 ppmv for new sources, measured dry and corrected to 7 

percent oxygen. For facilities that are required to use a 

continuous emissions monitoring system (CEMS), there would be a 

30 day averaging period.

Clinker Coolers

For clinker coolers a PM emissions limit of 0.085 lb/ton 

clinker for existing sources and 0.080 lb/tons clinker for new 

sources. 

Raw Material Dryers

THC. For raw materials dryers an emissions limit of 7 ppmv 

for existing sources and 6 ppmv for new sources, measured dry as 

propane and corrected to 7 percent oxygen, measured on a 30 day 

rolling average. Because the proposed existing source standard 

would be more stringent than the new source standard of 50 ppmv 
23

contained in the 1999 final rule for Greenfield new sources, we 

are also proposing to remove the 50 ppmv standard.

As an alternative to the THC standard, the raw material 

dryer can meet a standard of 2 ppmv total combined organic HAP 

for existing sources or 1 ppmv total organic HAP combined for 

new sources, measured dry and corrected to 7 percent oxygen. 

The alternative standard would be based on organic HAP emission 

testing that would establish a site specific THC limit that 

would demonstrate compliance with the total organic HAP limit. 

The site specific THC limit would be measured as a 30 day 

rolling average. 

B. Operating Limits

EPA is proposing to eliminate the restriction on the 

use of fly ash where the mercury content of the fly ash has been 

increased through the use of activated carbon. Given the 

proposed emission limitation for mercury, whereby kilns or 

cement kilns/in-line raw mills must continuously meet the 

mercury emission limits described above (including when using 

these materials) there does not appear to be a need for such a 

provision. For the same reason, EPA is proposing to remove the 

requirement to maintain the amount of cement kiln dust wasted 

during testing of a control device, and the provision requiring 

that kilns remove from the kiln system sufficient amounts of 

dust so as not to impair product quality.
24

C. Testing and Monitoring Requirements

We are proposing the following changes in testing and 

monitoring requirements:

Kilns and kiln/in-line raw mills would be required to meet the 

following changed monitoring/testing requirements:

 CEMS (PS-12A) or sorbent trap monitors (PS-12B) to 

continuously measure mercury emissions.

 CEMS meeting the requirement of PS-8A to measure THC 

emissions for existing sources (new sources are already 

required to monitor THC with a CEM). Kilns and kiln/inline raw mills meeting the organic HAP alternative to the 

THC limit would still be required to continuously monitor 

THC, and would also be required to test emissions using EPA 

Method 320 every five years to identify the organic HAP 

component of their THC emissions. 

 Installation and operation of a bag leak detection system

to demonstrate compliance with the PM emissions limit. If 

electrostatic precipitators (ESP) are used for PM control 

an ESP predictive model to monitor the performance of ESP 

controlling PM emissions from kilns would be required. As 

an alternative EPA is proposing that sources may use a PM 

CEMS that meets the requirements of PS-11. 

 CEMS meeting the requirements of PS-15 would be required to 

demonstrate compliance with the HCl standard. If a 
25

facility is using a caustic scrubber to meet the standard, 

EPA Test Method 321 may used in lieu of a CEMS to 

demonstrate compliance. The M321 test must be repeated 

every 5 years.

For clinker coolers, EPA is proposing use of a bag leak 

detection system to demonstrate compliance with the proposed PM 

emissions limit. If an ESP is used for PM control on clinker 

coolers, an ESP predictive model to monitor the performance of 

ESP controlling PM emissions from kilns would be required. As 

an alternative, EPA is proposing that a PM CEMS that meets the 

requirements of PS-11 may be used.

Raw material dryers that are existing sources would be 

required to install and operate CEMS meeting the requirement of 

PS-8A to measure THC emissions. (New sources are already 

required to monitor THC with a CEM). Raw material dryers

meeting the organic HAP alternative to the THC limit would still 

be required to continuously monitor THC, and would also be 

required to test emissions using EPA Method 320 every five years 

to identify the organic HAP component of their THC emissions. 

IV. Rationale for Proposed Amendments to Subpart LLL

A. MACT Floor Determination Procedure for all Pollutants

The MACT floor limits for each of the HAP and HAP 

surrogates (mercury, total hydrocarbons, HCl, and particulate 

matter) are calculated based on the performance of the lowest 
26

emitting (best performing) sources in each of the MACT pool 

sources. We ranked all of the sources for which we had data 

based on their emissions and identified the lowest emitting 12 

percent of the sources for which we had data, which ranged from 

two kilns for THC to 11 kilns for mercury for existing sources. 

For new source MACT, the floor was based on the best performing 

source. The MACT floor limit is calculated from a formula that 

is a modified prediction limit, designed to estimate a MACT 

floor level that is achievable by the average of the best 

performing sources (i.e., those in the MACT pool) if the best 

performing sources were able to replicate the compliance tests 

in our data base. Specifically, the MACT floor limit is an 

upper prediction limit (UPL) calculated from:10

UPL = xp + t * (VT)

0.5

where

Xp = average of the best performing MACT pool sources,

t = Student’s t-factor evaluated at 99 percent confidence, and 

vT = total variance determined as the sum of the within-source 

variance and the between-source variance.

 

10 More details on the calculation of the MACT floor limits are 

given in the technical memo in the docket and also in “Technical 

Support Document for HWC MACT Standards, Volume III: Selection 

of MACT Standards.” U.S. Environmental Protection Agency, Office 

of Solid Waste and Emergency Response. September 2005. Pages 7-

5 to 7-7.
27

The between-source variance is the variance of the average of 

the best performing source averages. The within-source variance 

is the variance of the MACT source average considering “m” 

number of future individual test runs used to make up the 

average to determine compliance. The value of “m” is used to 

reduce the variability to account for the lower variability when 

averaging of individual runs is used to determine compliance in 

the future. For example, if 30-day averages are used to 

determine compliance (m=30), the variability based 30-day 

averages is much lower than the variability of the daily 

measurements in the data base, which results in a lower UPL for 

the 30-day average.

B. Determination of MACT for Mercury Emissions from Major and 

Area Sources

The limits for existing and new sources we are proposing 

here apply to both area and major new sources. These limits 

would also apply to area sources consistent with section 

112(c)(6) of the Act, as EPA determined in the original rule. 

See 63 FR at 14193.

1. Floor Determination

Selection of existing source floor

Cement kilns’ emissions of mercury reflect exclusively the 

amounts of mercury in each kilns’ feedstock and fuel inputs. 

The amounts of mercury in these inputs vary by site. In many 
28

cases the majority of the mercury emissions result from the 

mercury present as a trace contaminant in the limestone, which 

typically comes from a propriety quarry located adjacent to the 

plant. Limestone is the single largest input, by mass, to a 

cement kiln’s total mass input, typically making up 80 percent 

of that loading. Mercury is also found as a trace contaminant 

in the other inputs to the kiln such as the additives that 

supply the required silica, alumina, and iron. Mercury is also 

present in the coal and petroleum coke typically used to fuel 

cement kilns. 

Mercury levels in limestone can vary significantly, both 

within a single quarry and between quarries. Since quarries are 

proprietary (one facility cannot access another’s limestone),

this variability is inherent and site-specific. Mercury levels 

in additives and fuels likewise vary significantly, although 

mercury emissions attributable to limestone often dominate the 

total due to the larger amount of mass input contributed by 

limestone (see further discussion of this issue at Other Options 

EPA considered in Setting Floor for Mercury below). 

The first step in establishing a MACT standard is to 

determine the MACT floor. A necessary step in doing so is 

determining the amount of HAP emitted. In the case of mercury 

emitted by cement kilns, this is not necessarily a 

straightforward undertaking. Single stack measurements 
29

represent a snapshot in time of a source’s emissions, always 

raising questions of how representative such emissions are of 

the source’s emissions over time. This problem is compounded in 

the case of cement kilns, because cement kilns do not emit 

mercury uniformly. For all kilns, the mercury content of the 

feed and fuels varies significantly from day-to-day and even 

hour-to-hour. For modern preheater and preheater/precalciner

kilns this problem is compounded because these kiln have in-line 

raw mills. With in-line raw mills, mercury is captured in the 

ground raw meal in the in-line raw mill and this raw meal 

(containing mercury) is returned as feed to the kiln. Mercury 

emissions may remain low during such recycling operations. 

However, as part of normal operation of a kiln raw mills must be 

periodically shut down for maintenance, and mercury-containing 

exhaust gases from the kiln are then bypassed directly to the 

main APCD device resulting in significantly increased mercury 

emissions at the stack. The result is that at any given time, 

mercury emissions from such cement kilns are either low or high, 

but rarely in equilibrium, so that single stack tests are likely 

to either underestimate or overestimate cement kilns’ 

performance over time. Put another way, we believe that single 

short term stack test data (typically a few hours) are probably 

not indicative of long term emissions performance, and so are 

not the best indicator of performance over time. With these 
30

facts in mind, we carefully considered alternatives other than 

use of single short-term stack test results to quantify kilns’ 

performance for mercury. 

An alternative to short term stack test data would be to 

use mercury continuous monitoring data over a longer time 

period. Because no cement kilns in the United States have 

continuous mercury monitors, this option was not available. 

However, mercury is an element, and can neither be created nor 

destroyed in a cement kiln. Therefore, all the mercury that 

enters a kiln has to leave the kiln in some fashion. The 

available data indicate that almost no mercury leaves the kiln 

as part of the clinker (product). Therefore, over the long term

all the mercury leaves the kiln as a stack emission with three

exceptions:

1. If instead of returning all particulate captured in the 

particulate control device to the kiln, the source

instead removes some of it from the circuit entirely, 

i.e., the kiln wastes some cement kiln dust (CKD); or

2. The kiln is equipped with an alkali bypass, which means all 

CKD captured in the alkali bypass PM control is wasted, 

and/or; 

3. If the kiln has a wet scrubber (usually for SO2 control), 

the scrubber will remove some mercury which will end up 

in the gypsum generated by the scrubber.
31

Based on these facts we determined the most accurate method 

available to us to determine long term mercury emissions 

performance was to do a total mass balance. We did so by 

obtaining data on all the kiln mercury inputs (i.e., all raw 

materials and all fuels) for a large group of kilns, and 

assuming all mercury that enters the kiln is emitted with the 

three exceptions noted above. Pursuant to letters mandating 

data gathering, issued under the authority of section 114, we 

obtained 30 days of daily data on kiln mercury concentrations in 

each individual raw material, fuel, and CKD for 89 kilns, along 

with annual mass inputs and the amount of material collected in 

the PM control device (or alkali PM control device) that is 

wasted rather than returned to the kiln. 

These data were submitted to EPA as daily concentrations 

for the inputs, i.e., samples of all inputs were taken daily and 

analyzed daily for their mercury content. We took the daily 

averages, calculated a mean concentration, and multiplied the 

mean concentration by annual materials use to calculate an 

annual mercury emission for each of the 89 kilns. If the 

facility wasted CKD, we subtracted out the annual mercury that 

left the system in the CKD. If the facility had a wet scrubber 

(the only control device currently in use among the sampled 

kilns with any substantial mercury capture efficiency), we 

subtracted out the annual mercury attributable to use of the 
32

scrubber. There are five cement kilns using wet scrubbers and 

EPA has removal efficiencies for four of these kilns (based on 

inlet/outlet testing conducted at EPA’s request concurrent with 

the input sampling). We attributed a removal efficiency for the 

fifth kiln based on the average removal efficiency of the other 

four kilns. 

For each kiln, we took this (calculated) annual emission

and then divided by total inputs to calculate an average 

emission factor – the average projected emission rate for each 

kiln. We then ranked each kiln from lowest average emission 

factor to highest. The resulting emissions factors for 87 of 

the 89 ranged (relatively continuously) from 7 to 300 pounds of 

mercury per million tons of feed. Two kilns showed considerably

higher numbers, approximately 1200 and 2000 pounds per ton of 

feed. These two facilities have atypically high mercury

contents in the limestone in their proprietary quarries which 

are the most significant contributors to the high mercury 

emissions. 

Based on these data and ranking methodology, the existing 

source MACT floor would be the average of the lowest emitting 12 

percent of the kilns for which we have data, which would be the 

11 kilns with lowest emissions (as calculated), shown in Table 

1. 

Table 1. Mercury MACT Floor
33

Kiln code Mercury emissions (lb/MM ton feed)

1233 7.14

1650 10.83

1589 11.11

1302 14.51

1259 15.16

1315 15.41

1248 18.09

1286 21.12

1435 22.89

1484 22.89

1364 23.92

MACT - Existing Kilns

Average: lb/MM tons 

feed (lb/MM tons 

clinker)

16.6 (27.4)

Variability (t*vT

0.5)

9.52

99th percentile: lb/MM 

tons feed (lb/MM tons 

clinker)

26 (43)

MACT - New Kilns

Average: lb/MM tons 

feed (lb/MM tons 

clinker)

7.1 (11.8)

Variability (t*vT

0.5)

1.3

99th percentile: lb/MM 

tons feed (lb/MM tons 

clinker)

8.4(14)

The average emission rate for these kilns is 16.6 pounds

per million tons (lb/MM) tons feed (27.4 lb/MM tons clinker). 

The emission rate of the single lowest emitting source is 7.1

lb/MM tons feed (11.8 lb/MM tons clinker). 

As previously discussed above, we account for variability 

in setting floors, not only because variability is an element of 

performance, but because it is reasonable to assess best 
34

performance over time. Here, for example, we know that the 11 

lowest emitting kiln emission estimates are averages, and that 

the actual emissions will vary over time. If we do not account 

for this variability, we would expect that even the kilns that 

perform better than the floor on average would potentially 

exceed the floor emission levels a significant part of the time 

-- meaning that their performance was assessed incorrectly in 

the first instance.

For the 11 lowest emitting kilns, we calculated a daily 

emission rate using the daily concentration values and annual 

materials inputs divided by each kiln’s operating days.11 The 

results are shown in Table 1 and represent the average 

performance of each kiln over the 30-day period. We then 

calculated the average performance of the 11 lowest emitting 

kilns (17 lb/MM tons of feed) and the variances of the daily 

emission rates for each kiln which is a direct measure of the 

variability of the data set. This variability includes the dayto-day variability in the total mercury input to each kiln and 

variability of the sampling and analysis methods over the 30-day 

period, and it includes the variability resulting form site-to-

 

11 In the daily calculations, we treated the CKD removal as if it 

was a control device, and applied the overall percent reduction 

rather that using the daily CKD concentration value. We used 

this approach because if we used daily CKD removal values, some 

days showed negative mercury emissions rates. This is because 

of the mercury recycling issues discussed above. 
35

site differences for the 11 lowest emitters. We calculated the 

MACT floor (26 lb/MM tons feed) based on the UPL (upper 99th

percentile) as described earlier from the average performance of 

the 11 lowest emitting kilns, Students t-factor, and the total 

variability, which was adjusted to account for the lower 

variability when using 30 day averages. 

EPA also has some information which tends to corroborate 

the variability factor used to calculate the floor for mercury. 

These data are not emissions data; they are data on the total 

mercury content of feed materials over periods of 12 months or 

longer. Because mercury emissions directly correlate with 

mercury content of feed materials, we believe an analysis of the 

variability of the feed materials is an accurate surrogate for 

the variability of mercury emissions over time. These long term 

data are from multiple kilns from a single company that are not 

ranked among the lowest emitters, but are nonetheless germane as 

a crosscheck on variability of mercury content of feed materials 

(including whether 30 days of sampling, coupled with 

statistically derived variability of that data set and a 99th

percentile, adequately measures that variability). 

One way of comparing the variability among different data 

sets with different average values is to calculate the relative 

standard deviations (RSD), which is the standard deviation 

divided by the mean. If the RSD are comparable, then one can 
36

conclude that the variability among the data sets is comparable. 

The results of such an analysis are given in Table 2 below. The 

long term data represent long term averages of feed material 

mercury content based on 12 months of data or more, whereas the 

MACT data sets are for 30 consecutive days of data. The RSD of 

the long term data are comparable to and within the same range 

as the RSD for the MACT data. This comparison suggests our 

method of calculating variability in the proposed floor by using

variances/99th percentile UPL appears to adequately encompass 

sources’ long-term variability.

Table 2. Comparison of Long-Term Kiln Feed Mercury Concentration at 

Essroc Plants with the Feed Mercury Concentration Data for the MACT 

Floor Kilns

PPM Hg in Feed

Kiln Mean

Standard 

Deviation RSD Source

1248a 0.021 0.002 0.10 MACT floor kilnb

1589a 0.021 0.002 0.10 MACT floor kiln

1435 0.012 0.002 0.16 MACT floor kiln

1484 0.012 0.002 0.16 MACT floor kiln

1233 0.011 0.002 0.16 MACT floor kiln

1650 0.025 0.005 0.22 MACT floor kiln

Speed 0.055 0.016 0.29 Essrocc

1286 0.006 0.002 0.32 MACT floor kiln

1364 0.006 0.002 0.32 MACT floor kiln

San Juan 0.322 0.108 0.34 Essroc

Bessemer 0.021 0.007 0.35 Essroc

Logansport 0.022 0.008 0.37 Essroc

Naz III 0.016 0.010 0.61 Essroc

Naz I 2.974 1.838 0.62 Essroc

1302 0.006 0.004 0.68 MACT floor kiln

1315 0.006 0.004 0.68 MACT floor kiln

Martinsburg 0.023 0.017 0.89 Essroc

1259 0.008 0.007 0.89 MACT floor kiln

Picton 0.075 0.078 1.05 Essroc
37

a Same feed sample applied to multiple kilns at the plant

b MACT floor kilns’ variabilities are all based on approximately 30 

days of data

c Essroc kiln’s variabilities are all based on 12 months to three 

years of data.

We are proposing to express the floor as a 30 day rolling 

average. There are two reasons for doing so. First, as 

explained earlier, daily variations in mercury emissions at the 

stack for all kilns with in-line raw mills is greater than daily 

variability of mercury levels in inputs. This is because 

mercury is emitted in high concentrations during mill-off

conditions, but in lower concentrations when mercury is recycled 

to the kiln via the raw mill (‘mill-on’). We believe that 30 

days is the minimum averaging time that allows for this millon/mill-off variation.

Second, a 30 day rolling average is tied to our proposed 

implementation regime, which in turn is based on the means by 

which the data used to generate the standard were developed. As 

explained above, the proposed floor reflects 30 days of sampling 

which are averaged, corresponding to the proposed 30-day 

averaging period. EPA is also proposing to monitor compliance 

by means of daily monitoring via a CEMS, so that the proposed 

implementation regime likewise mirrors the means by which the 
38

underlying data were gathered and used in developing the 

standard. 

Critical to this variability calculation is the assumption 

that EPA is adequately accounting for variable mercury content 

in kiln inputs.12 As noted, we did so based on 30-days of 

continuous sampling of all kiln inputs, plus use of a further 

statistical variability factor (based on that data set) and use 

of the 99th percentile UPL. The 30-day averaging time in the 

standard is a further means of accounting for variability, and 

accords with the data and methodology EPA used to develop the 

floor level. 

We solicit comment on the accuracy of this analysis. The 

most pertinent information, would of course be further sampling

data of inputs to specific kilns (especially data from sampling 

over a longer period than 30-days).13 EPA also expressly 

solicits further information regarding potential 

 

12 Since only five kilns have stack control devices, variability 

of performance of these controls (wet scrubbers), although 

important, plays a less critical role in this analysis.

13 Some advance commenters have posited a larger variability 

factor to reflect the historic known variation in mercury 

content in limestone and other inputs, as reflected in various 

geological surveys. However, at issue is not variability for 

the source category as a whole, but specific sources’ 

variability. So any resort to information not coming directly 

from a best performer’s own operating history must be 

accompanied by an explanation of its relevance for best 

performer’s variability in ordered to be considered relevant. 

See 479 F. 3d at 881-82.
39

substitutability of non-limestone kilns inputs and whether kilns 

actually utilize inputs other than those reflected in the 30-day 

sampling effort comprising EPA’s present data base for mercury, 

and if so, what mercury levels are in these inputs.

Selection of new source floor

Based on Table 1, the average associated with the single 

lowest emitting kiln is 7 lb/MM tons feed (12 lb/MM tons 

clinker). Applying the UPL formula discussed earlier based on 

the daily emissions for the best performing kiln, we calculated 

its 99th percentile UPL of performance, which results in a new 

source MACT level of 8.4 lb/MM tons feed (14 lb/MM tons 

clinker).

Because this new source floor is on a different basis than 

the standard EPA promulgated in December 2006, which was a 41 

μg/dscm not to be exceeded standard, it is difficult to directly 

compare the new source floor proposed in this action to the 

December 2006 standard. The December 2006 new source mercury 

emissions limit was based on the performance of wet scrubberequipped cement kilns. In our current analysis these wet 

scrubber-equipped kilns were among the lowest emitting kilns, 

but not the lowest emitting kiln used to establish this proposed 

new source limit. Based on this fact, we believe this proposed 

new source floor (and standard, since EPA is not proposing a 
40

beyond-the-floor standard) is approximately 30 percent lower 

that the December 2006 standard. 

Other Options EPA Considered in Setting Floors for Mercury

EPA may create subcategories which distinguish among 

“classes, types, and sizes of sources”. Section 112 (d)(1). 

EPA has carefully considered that possibility in considering 

potential standards for mercury emitted by portland cement 

kilns. Were EPA to do so, each subcategory would have its own 

floor and standard, reflecting performance of the sources within 

that subcategory. EPA may create a subcategory applicable to a 

single HAP, rather than to all HAP emitted by the source 

category, if the facts warrant (so that, for example, a 

subcategory for kilns emitting mercury, but a single category 

for kilns emitting HCl, is legally permissible with a proper 

factual basis). Normally, any basis for subcategorizing must be 

related to an effect on emissions, rather than to some 

difference among sources which does not affect emissions 

performance. 

The subcategorization possibilities for mercury which we 

considered are the type of kiln, presence of an inline raw mill, 

practice of wasting cement kiln dust, mercury concentration of 

limestone in the kiln’s proprietary quarry, or geographic 

location. Mercury emissions are not affected by kiln type 
41

(i.e., wet or dry, pre-calcining or not) because none of these 

distinctions have a bearing on the amount of mercury inputted to 

the kiln or emitted by it. In contrast, the presence of an inline raw mill affects mercury emissions in the short term 

because the in-line raw mill tends to collect mercury in the 

exhaust gas and transfer it to the kiln feed. However, since 

(as discussed above) the raw mill must be shutdown periodically 

for maintenance while the kiln continues to operate, all or most 

of the collected mercury simply gets emitted during the raw mill 

shutdown and total mercury emissions over time are not changed. 

The practice of wasting cement kiln dust does affect 

emissions. This practice means that a portion of the material 

collected on the PM control device is removed from the kiln 

system, rather than recycled to the kiln. Some of the mercury 

condenses on the PM collected on the PM control device, so 

wasting CKD also removes some mercury from the kiln system (and 

therefore it is not emitted). However, since this practice 

could be considered to “control” mercury, subcategorization by 

CKD wasting would be the same as subcategorizing by control 

device, which is not permissible. See 69 FR at 403 (Jan. 5, 

2004).

There is no variation in kiln location (i.e., geographical 

distinction) which would justify subcategorization. We examined 

the geographical distribution of mercury emissions and total 
42

mercury and found no correlation. For example, no one region of 

the country has kilns that tend to be all low or high emitting 

kilns. 

We also rejected subcategorization by total mercury inputs. 

Subcategorization by this method would inevitability result in a 

situation where kilns with higher total mercury inputs would 

have higher emission limits. This is because total mercury 

inputs are directly correlated with mercury emissions. So a 

facility that currently has lower mercury inputs could 

potentially simply substitute a higher mercury raw material 

without any requirement to control the additional mercury. In 

addition, fuels and other additives are non-captive situations, 

and thus do not readily differentiate kilns by “size, class, or 

type”. Finally, because of the direct correlation of mercury 

emissions and mercury inputs, subcategorization by total mercury 

inputs could potentially be viewed as a similar situation to 

subcategorization by control device. 

The subcategorization option that we believe is most 

pertinent would be to subcategorize by the facility’s

proprietary limestone quarry. All cement plans have a limestone 

quarry located adjacent to or very close to the cement plant. 

This quarry supplies limestone only to its associated plant, and 

is not accessible to other plants. Typically quarries are 

developed to provide 50 to 100 years of limestone, and the 
43

cement kiln is located based on the location of the quarry. See 

70 FR at 72333. For this reason, we believe that a facility’s 

propriety quarry is an inherent part of the process such that 

the kiln and the quarry together can be viewed as the affected 

source. Also, the amount of mercury in the proprietary quarry 

can significantly affect mercury emission because (as noted 

above) limestone makes up about 80 percent of the total inputs 

to the kiln. Thus, kilns with mercury above a given level might 

be considered a different type or class of kiln because their 

process necessarily requires the use of that higher-mercury 

input. 

The facts, however, do not obviously indicate sharp 

disparities in limestone mercury content that readily 

differentiates among types of sources. Figure 1 presents the 

average mercury contents of the proprietary quarries on the 89 

kilns in EPA’s present data base. 
44

Figure 1. Average Mercury Concentration of Limestone

These data, as we presently evaluate them, do not readily 

support a subcategorization approach – putting aside for the 

moment the high mercury limestone kilns (at the far right of the 

distribution tail in Figure 1) which are discussed separately. 

As shown in Figure 1, mercury levels in limestone are more of a 

continuum with no immediately evident breakpoints (again, 

putting aside the high-mercury limestone kilns). More 

important, kilns with quarries with varied mercury content can 

and do have similar mercury emissions, and in many instances, 

limestone mercury is not the dominant source of mercury in the 

kilns’ emissions notwithstanding that limestone is the principal 

Average Mercury Content of Limestone

0.00

200.00

400.00

600.00

800.00

1000.00

1200.00

0 10 20 30 40 50 60 70 80 90 100

Kiln Number

Avg ppb Hg in Limestone
45

volumetric input. Thus for about 55 percent of the kilns (49 of 

89), non-limestone mercury accounted for greater than 50 percent 

of the kiln’s mercury emissions.

15 For nearly 70 percent of the 

kilns (62 of 89), limestone mercury accounted for at least onethird of total mercury emissions.

Table 3. Origins of Mercury in Portland Cement 

Manufacturing

Random 

number kiln 

code

Percent Hg 

from other 

raw 

materials

Percent Hg 

from fuels

Percent Hg 

from 

limestone

Total %

1356 91 1 8 100

1538 89 1 10 100

1630 84 2 15 100

1530 53 32 15 100

1610 10 73 17 100

1494 54 28 17 100

1560 76 5 18 100

1219 71 8 20 100

1335 55 21 25 100

1597 49 26 25 100

1437 50 25 25 100

1559 19 55 26 100

1246 65 9 26 100

1316 65 9 26 100

1308 1 72 27 100

1521 1 72 27 100

1536 0 73 27 100

1520 34 38 27 100

1253 60 11 29 100

1639 60 11 29 100

1390 60 11 29 100

1323 60 11 29 100

 

15 In certain instances, percentages of non-limestone mercury are 

high because limestone mercury content was low. However, in 

many instances, non-limestone mercury contributions exceeded 

those from limestone even where limestone mercury contribution 

was relatively high. See Table 3.
46

1663 60 11 29 100

1655 13 57 30 100

1591 13 57 30 100

1582 13 57 30 100

13642 66 32 100

12862 65 33 100

1436 15 5035 100

1396 614 35 100

1443 575 38 100

1660 11 50 39 100

1371 16 44 40 100

1619 16 43 40 100

1594 12 46 42 100

1331 12 44 44 100

14173 53 44 100

12403 53 44 100

1233 41 14 46 100

16383 48 48 100

1635 417 52 100

1220 406 53 100

1294 415 54 100

1256 415 54 100

1350 415 54 100

1343 415 54 100

1604 22 23 55 100

1327 21 23 57 100

1259 23 20 57 100

1615 21 21 58 100

1375 21 20 59 100

1448 17 24 59 100

1337 17 24 59 100

1481 355 60 100

1435 25 13 62 100

1484 25 13 62 100

1463 13 25 62 100

1421 27 11 62 100

1439 11 27 63 100

1415 297 63 100

12005 32 63 100

12185 32 63 100

1226 11 26 64 100

1589 305 64 100

12684 31 65 100

1225 11 23 66 100

16431 33 67 100
47

1674 1 32 67 100

1592 11 21 68 100

1650 3 28 68 100

1251 16 13 70 100

1265 16 11 73 100

1315 7 19 74 100

1239 17 8 74 100

1302 7 17 76 100

1686 19 6 76 100

1248 17 6 76 100

1419 16 8 77 100

1692 13 8 79 100

1693 7 13 80 100

1324 1 16 83 100

1339 8 9 84 100

1376 5 8 87 100

1690 5 8 87 100

1688 5 8 87 100

1609 13 0 87 100

1581 9 3 88 100

1647 5 7 89 100

1629 8 0 92 100

These data seem to indicate that although quarry mercury 

content is important, other non-proprietary inputs can and do 

affect mercury emissions as well, often to an equal or greater 

extent. Quarries with similar limestone mercury content can and 

do have very different mercury emissions. These facts, plus the 

general continuum in the limestone mercury data, seem to 

mitigate against subcategorizing on this basis for the great 

bulk of industry sources. 

Moreover, as stated above, subcategorization is limited by 

the CAA to size, class, or type of source. Both EPA and advance

commenters applied various statistical analyses to the mercury 
48

limestone quarry data set and these analyses indicated that 

there could be populations of quarries that were statistically 

different. However, it is unclear to us that a statistical 

difference in a population is necessarily the same as a 

distinction by size, class, or type. More compelling facts, at 

least in our present thinking, are the apparent continuum of 

limestone mercury levels, and the fact that limestone mercury 

levels are less of a driver of mercury emission levels than one 

would expect if this is to be the basis for subcategorization 

across a broad set of the facilities. EPA is also concerned 

that subcategorization by quarry mercury content may allow some 

higher-emitting facilities to do relatively less for compliance 

were they to be part of a separate subcategory where mercury 

levels of best performers were comparatively high. (Of course, 

these levels could be reduced by adopting standards reflecting 

beyond-the-floor determinations.) Conversely, the case could 

occur where a lower emitter might be subject to a greater degree 

of control than a high emitter. For example, if we were to 

establish a subcategory at 20 ppb mercury in the limestone, at

kilns at just below the 20 ppb level might be required to apply 

mercury controls while kilns just above the 20 ppb level, which 

would likely include kilns that would determine the floor level 

of control, would have to do nothing to meet the mercury 

standard. 
49

Much of this analysis, however, does not apply to the kilns 

at the far end of the distribution, especially the two 

facilities shown in Figure 1 which have the highest quarry 

mercury contents which quarries appear to be outliers from the 

general population. These sources’ mercury emissions are

related almost entirely to the limestone mercury content, not to 

other inputs. In addition, we noted that if we set up a 

separate subcategory for these facilities, even if we proposed a 

beyond-the-floor standard based on the best estimated 

performance of control for these two facilities, their emissions 

limit would potentially be 500 to 800 lb/MM tons clinker, which 

is well above any other kiln, even when uncontrolled, in our 

data base, and 8 to 13 times the floor established for other 

existing sources (assuming no further subcategorization).

EPA is not proposing to create a separate subcategory for 

these high mercury sources. Mercury is a dangerous neurotoxin 

singled out for special control under the Act’s air toxics 

provision (see section 112(c)(6)), and kilns in a high-mercury 

subcategory, no matter how well controlled, would still be 

allowed to emit large amounts (at least pending a section 112(f) 

residual risk determination)). EPA is also mindful of the 

holding of Brick MACT and other decisions that EPA must account 

for raw material HAP contributions in establishing MACT floors, 

and the fact that raw materials may be proprietary or otherwise 
50

not obtainable category-wide does not relieve EPA of that 

obligation. See, e.g. 479 F. 3d at 882-83. 

There are also competing considerations here, both legal 

and equitable. There is legal support for sources limited to a 

particular type of high-HAP feedstock being a legitimate 

candidate for subcategorization. Thus, the concurring opinion 

in Brick MACT would expressly countenance subcategorization in 

situations involving sources’ dependence on high-HAP raw 

materials to avoid situations where a level of performance 

achieved by some sources proves unachievable by other sources 

even after application of best technological controls, viewing 

such sources as of a different type than others in the source 

category. 479 F. 3d at 884-85. A further equitable

consideration is that one of the high mercury kilns here has 

voluntarily entered into an enforceable agreement to install 

activated carbon (the best control technology currently 

available so far as is known) to control its mercury emissions 

and this agreement appears to have the support of directly 

affected stakeholders (local citizen groups, regional and state 

officials).17 The company is poised to begin installation of the 

control technology. However, neither EPA nor the company 

believes that this source could physically achieve the level of 

 

17 Minutes of meeting between EPA and representatives of Ash 

Grove Cement. February 27, 2009.
51

the mercury floor derived from a single source category 

approach. Closure of this kiln due to a technically infeasible 

standard for mercury, and possibly several of the other highest

mercury kilns, thus is a possible consequence.

EPA repeats that it is not proposing any subcategories for 

mercury due to the nature of the HAP at issue, and EPA’s desire 

to adopt a clearly legally defensible standard. Nonetheless, 

this remains an issue EPA intends to evaluate carefully based on 

public comment, and expressly solicits comment addressing all 

aspects of determinations whether or not to subcategorize. 

These comments should address not only the issue of a highmercury subcategory (addressing plants in the upward right-hand 

tail of the distributional curve in Figure 1), but other sources 

as well. EPA also solicits comment regarding non-limestone 

inputs to cement kilns, and whether there is any potential basis 

for considering a subcategorization approach (which passes legal 

muster) involving such materials.18

Other Alternatives Considered for Mercury Standard

 

18 One of these high-mercury sources suggested that because it is 

an area source, EPA develop a mercury standard for it based upon 

Generally Available Control Technology (GACT) rather than MACT. 

See section 112 (d)(5) of the Act. Aside from questions about

whether use of activated carbon is a generally available control 

technology here, EPA has already determined that all cement 

kilns’ mercury emissions are subject to MACT under authority of 

section 112(c)(6). See 63 FR at 14193.
52

EPA is proposing to rank sources by emission level in 

determining which are best performing. We also considered 

another option of ranking best performers based on their 

relative mercury removal efficiency, and presenting a standard 

so-derived as an alternative to the standard based on ranking by 

lowest emissions. There is some statutory support for adopting 

percent reduction/removal efficiency methodologies. The MACT 

floor for new sources is to be based on the performance of the 

“best controlled” similar source, the term “control” can be read 

to mean control efficiency. It can also be argued that the 

critical terms of section 112 (d)(3) -- "best controlled" (new) 

/"best performing" (existing) -- do not specify whether "best" 

is to be measured on grounds of control efficiency or emission 

level. See Sierra Club v. EPA, 167 F.3d 658, 661 (" average 

emissions limitation achieved by the best performing 12 percent 

of units' * * * on its own says nothing about how the 

performance of the best units is to be calculated"). Existing

floors determined and expressed in terms of control efficiency 

are also arguably consistent with the requirement that the floor 

for existing sources reflect "average emission limitation 

achieved", since "emission limitation" includes standards which 

limit the "rate" of emissions on a continuous basis—something 

which percent reduction standards would do. CAA section 302(k). 

There are also instances, where Congress expressed performance 
53

solely in terms of numerical limits, rather than performance 

efficiency, suggesting that Congress was aware of the 

distinction and capable of delineating it. See CAA section 

129(a)(4).19 

There are also arguments that percent reduction standards 

are not legally permissible. The Brick MACT opinion states in 

dicta that best performers are those emitting the least HAP(see

479 F. 3d at 880 referring to (“section [112 (d)(3)] requires 

floors based on emission levels actually achieved by best 

performers (those with the lowest emission levels)”).20 More 

important, the opinion stresses that raw material inputs must be 

accounted for in determining MACT floors. Id. at 882-83. A 

problem with percent reduction standards is that they downplay 

the role of HAP inputs on emissions by allowing more HAP to be 

emitted provided a given level of removal efficiency reflecting 

the average of best removal efficiencies is achieved. That 

would certainly be the case for portland cement kilns. For 

these reasons, EPA is not proposing alternative standards for 

mercury expressed as percent reduction reflecting the average of 

 

19 See also section 112(i)(5)(A), which allows sources that 

achieve early reductions based on measured rates of removal 

efficiency a reprieve from MACT.

20 The issue of whether best performers can be based on source’s 

removal efficiency was not presented in Brick MACT, or any of 

the other decided cases.
54

the best removal efficiencies. EPA solicits comment on this 

alternative from both a legal and policy standpoint, however.

2. Beyond the Floor Determination

We are not proposing any beyond-the-floor standards for 

mercury. When we establish a beyond the floor standard we 

typically identify control techniques that have the ability to 

achieve an emissions limit more stringent than the MACT floor. 

Under the proposed amendments, most existing kilns would have to 

have installed both a wet scrubber and activated carbon 

injection (ACI) for control of mercury, HCl and THC.21 To achieve 

further reductions in mercury beyond what can be achieved using 

wet scrubber and ACI in combination, the available options would 

include closing the kiln and relocating to a limestone quarry 

having lower mercury concentrations in the limestone, 

transporting low-mercury limestone in from long distances, 

switching other raw materials to lower the amount of limestone 

in the feed, wasting CKD, and installing additional add-on 

control devices. For reasons discussed further below we believe 

that all but the latter option (add-on controls) cannot be 

evaluated as the basis of a national potential beyond the floor 

standard because the data to perform this type of analysis for 

 

21 Summary of Environmental and Cost Impacts of Proposed 

Revisions to Portland Cement NESHAP (40 CFR Part 63, subpart 

LLL), April 17, 2009.
55

each facility do not exist. For that reason, we estimated the 

cost and incremental reduction in mercury emissions associated 

with installing another control device in series to the other 

controls. The add-on controls considered included a wet 

scrubber and ACI. Because ACI is less costly and is expected to 

have a higher removal efficiency as well as being potentially 

capable of potentially removing elemental mercury (using 

halogenated carbon) which a scrubber cannot remove, we selected 

ACI as the beyond-the-floor control option.

We estimated the costs and emission reductions for a 1.2 

million tpy kiln as it would be representative of the impacts of 

other kilns. Annualized costs for an additional ACI system would 

be $1.254 million per year. The quantity of mercury leaving the 

upstream controls would be an estimated 3.3 lb/yr. Assuming a 

90 percent control efficiency, the additional ACI system would 

remove about 3.0 lb/yr of mercury for a cost-effectiveness of 

approximately $420,000 per lb of mercury reduction. A 90 

percent removal efficiency may be optimistic given the lower 

level of mercury entering the device and a removal efficiency on 

the order of 70 percent is more likely. At this efficiency, the 

additional mercury controlled would be 2.3 lb/yr for a cost 

effectiveness of approximately $540,000 per pound of mercury 

removed. At either control efficiency, we believe cost of 

between $420,000 and $540,000 per pound of mercury removed is 
56

not justified and we are therefore not selecting this beyondthe-floor option. 

There are two potential feasible process changes that have 

the potential to affect mercury emissions. These are removing 

CKD from the kiln system and substituting raw materials, 

including fly ash, or fossil fuels with lower-mercury inputs. 

Although substituting low-mercury materials and fuel may be 

feasible for some facilities, this alternative would depend on 

site-specific circumstances and, therefore, must be evaluated on 

a site-by-site basis and EPA’s current view is that it would not 

be a uniformly applicable (or quantifiable) control measure on 

which a national standard could be based (although as noted 

earlier, EPA is expressly soliciting quantified comment 

regarding potential substitutability of non-limestone kiln 

inputs). 

Based on material balance data (feed and fuel usage, 

control device catch recycling and wasting, and mercury 

concentrations) that we gathered with our survey of 89 kilns, 58 

percent of kilns waste some amount of CKD while 42 percent waste 

none. Among kilns that waste CKD, the percentage reduction in 

mercury emissions by wasting CKD ranged from 0.13 percent to 82 

percent, with an average of 16.5 percent and median of 7 

percent. For kilns that waste some CKD, CKD as a percentage of 

total feed ranges from 0.16 percent to 13.7 percent, with a mean 
57

of 4.5 percent. Any additional emission reductions that can be 

achieved by wasting CKD depend on several site-specific factors 

including: 

 The concentration of mercury in raw feed and fuel 

materials. 

 The concentration of mercury in the CKD. 

 The amount of CKD already being wasted.

 The dynamics of mercury recirculation and accumulation -

Internal loops for mercury exist between the control device 

and kiln feed storage and the kiln for long dry and wet 

kilns. For preheater and precalciner kilns, there is 

usually an additional internal loop involving the in-line 

raw mill. These internal loops and the distribution of 

mercury throughout the process are not predictable and can 

only be determined empirically.

 Mercury speciation may affect the extent to which mercury 

accumulates in the CKD, with particulate and oxidized 

mercury more likely to accumulate while elemental mercury 

is likely emitted and not affected by CKD wasting.

Reducing mercury emissions through the wasting of CKD may 

be feasible for some kilns that do not already waste CKD or by 

wasting additional CKD for some kilns that already practice CKD 

wasting. However the degree to which CKD can be used to reduce 

mercury emissions cannot be accurately estimated due to several 
58

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 CKD decreases. 

We do not have long-term data to quantify the relationship 

between amount of CKD wasted, CKD mercury concentration and 

emissions. 

The ability to reduce mercury emissions by wasting more CKD 

also is affected by the mercury species present. The 

particulate and oxidized species of mercury can accumulate 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 speciation. 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 crossmedia impact EPA is required to consider is making beyond-thefloor determinations. The interaction of these factors is 

complex and has not been adequately studied. 

One cement plant has investigated the potential to reduce 

mercury emissions by wasting CKD. This facility, using mercury 

CEMS and material balance information, estimated that wasting 

100 percent of CKD when the raw mill is off (about 19,000 tons 
59

of CKD or 16 percent of total baghouse catch, or 1 percent of 

total feed) would reduce mercury emissions by about 4 percent. 

They did not estimate the reductions in mercury emissions by 

wasting more CKD. As with the potential to reduce mercury 

emissions using raw materials substitution, the effectiveness of 

CKD wasting in reducing emissions may provide cement plants the 

ability to reduce mercury emissions but it will have to be 

determined on a site-by-site basis.

Because the degree to which mercury emissions can be 

reduced by material substitutions or through the wasting of CKD 

are site specific, these process-related work practices were not 

considered as beyond-the-floor options. 

As a result of these analyses, we determined that, 

considering the technical feasibility and costs, there is no 

reasonable beyond the floor control option, and are proposing a 

mercury emission limit based on the MACT floor level of control.

C. Determination of MACT for THC Emissions from Major and Area

Sources

The limits for existing and new sources we are proposing 

here apply to both area and major new sources. We have applied

these limits to area sources consistent with section 112(c)(6). 

See 63 FR 14193 (THC as a surrogate for the 112(c)(6) HAP 

polycyclic organic matter and polychlorinated biphenyls, plus 
60

determination to control all THC emissions from the source 

category under MACT standards).

1. Floor Determination

Selection of existing source floor

For reasons previously discussed in the initial proposal of 

the Portland Cement NESHAP (63 FR 14197, March 24, 1998), we are 

proposing to use THC as a surrogate for non-dioxin organic HAP

that are emitted from the kiln (as is the current rule). The 

THC data used to develop the MACT floor were obtained from 12 

kilns using CEMS to continuously measure the concentration of 

THC exiting each kiln’s stack. Only kilns 1 (regenerative 

thermal oxidizer (RTO)) and kilns 11 and 12 (ACI) have THC 

emissions controls which remove or destroy THC. We also 

obtained THC data from manual stack tests, typically based on 3 

one hour runs per test. The CEMS data are superior to the 

results of a single stack test for characterizing the long term 

performance and in determining the best performing kilns with 

respect to THC emissions for several reasons. The manual stack 

test is of short duration and only represents a snapshot in 

time; consequently, it provides no information on the 

variability in emissions over time due to changes in raw 

material feed or in kiln operating conditions. In contrast, the 

CEMS data include measurements that range from 31 consecutive 

days to almost 900 days of operation for the various kilns.
61

This extended duration of the CEMS test data gives us confidence 

that for any particular kiln CEMS data will capture the 

variability associated with the long-term THC emissions data, 

and thus give the most accurate representation of a source’s 

performance. In addition, a MACT standard based on CEMS data 

would be consistent with the way we are proposing to implement 

the THC emission limit (i.e., by requiring continuous monitoring 

with a THC CEMS).

In order to set MACT floors we are ranking the kilns based 

on the average THC emissions levels (in ppmv) achieved (i.e.,

each kiln’s averaged performance, averaged over the number of 

available measurements. This ranking is shown in Table 4. 

Table 4. Summary of THC CEMS Data and MACT Floor

Kiln Average Number 

of 

readings

Kiln type Inline 

raw 

mill

Kiln 1 4.0 35 Preheater/precalciner yes

Kiln 2 5.6 695 Wet no

Kiln 3 6.8 692 Long dry no

Kiln 4 6.8 31 Preheater/precalciner yes

Kiln 5 11.1 702 Long dry no

Kiln 6 23.7 470 Preheater/precalciner no

Kiln 7 45.0 742 Preheater/precalciner yes

Kiln 8 51.6 774 Preheater/precalciner yes

Kiln 9 51.9 843 Preheater/precalciner yes

Kiln 10 62.8 880 Preheater/precalciner yes

Kiln 11 and 

Kiln 12 

Combined

748.1 790 Wet no

Existing 

Source 

Average 

(ppmvd at 

4.8
62

7% O2, 

propane)

Variability 

(t*vT

0.5)

1.9

Existing 

Source 99th

percentile 

(ppmvd at 

7% O2, 

propane)

7

New Source 

Average 

(ppmvd at 

7% O2, 

propane)

4.0

Variability 

(t*vT

0.5)

1.5

New Source 

99th

percentile 

(ppmvd at 

7% O2, 

propane)

6

The average performance of the best performing 12 percent 

of kilns (2 kilns) is 4.8 ppmvd THC (a daily average expressed 

as propane at 7 percent oxygen). We calculated variability 

based on the variances of the two lowest emitting kilns. This 

includes day-to-day variability at the same kiln, variability 

among the two lowest emitting kilns, and because one dataset 

included 695 daily measurements, it represents long term 

variability at a single kiln. We calculated the MACT floor (7 

ppmvd) based on the UPL (upper 99th percentile) as described 

earlier from the average performance of the 2 lowest emitting 

kilns, Students t-factor, and the total variability, which was 
63

adjusted to account for the lower variability when using 30 day 

averages.

Selection of new source MACT floor

The new source MACT floor would be the best performing 

similar source accounting for variability, which would be 6

ppmvd. We used the same procedure in estimating variability for 

the new source based on the 35 observations reported. 

In this case the proposed new and existing source MACT 

floors are almost identical because the best performing 12 

percent of kilns (for which we have emissions information) is 

only two sources. The reason we look to the best performing 12 

percent of sources is that the cement kiln source category 

consists of 30 or more kilns. Section 112 (d)(3) states that if 

the source category or subcategory contains 30 or more sources 

then the best performing 12 percent of the kilns for which the 

administrator has data must be used to set the existing source 

MACT floor. However, in cases where there are 30 or more 

sources but little emission data this results in only a few 

kilns setting the existing source floor with the result that the 

new and existing source MACT floors are almost identical. In 

contrast, if this source category had less than 30 sources, we 

would be required to use the top five best performing sources, 
64

rather than the two that comprise the top 12 percent. Section 

112 (d)(3)(B). 

We are seeking comment on whether, with the facts of this 

rulemaking, we should consider reading the intent of Congress to 

allow us to consider five sources rather than just two. First, 

it seems evident that Congress was concerned that floor 

determinations should reflect a minimum quantum of data: at 

least data from five sources for source categories of less than 

30 sources (assuming that data from five sources exist). 

Second, it does not appear that this concern would be any less 

for source categories with 30 or more sources. The concern, in 

fact, would appear to be greater. That is, floors for 

categories with 30 or greater sources should not be based on a 

smaller number of best performing sources than source categories 

of fewer than 30 sources.22 We note further that if we were to 

use five sources as best THC performers here, the existing 

source floor would be 10 ppmvd. We are specifically requesting 

comment on interpretive and factual issues relating to the 

proposed THC floors, and also reiterate requests for further THC 

performance data, especially from kilns equipped with CEMs. 

 

22 As noted, basing the proposed existing source THC floor on 

data from two sources (i.e. 12 percent of the 15 sources for 

which we have CEM data) largely eliminates the distinction 

between new and existing source THC floors. Yet this is an 

important statutory distinction. 
65

EPA is also proposing an alternative floor for non-dioxin 

organic HAP, based on measuring the organic HAP itself rather 

than the THC surrogate. This equivalent alternative limit 

would provide additional flexibility in determining compliance, 

and it would be appropriate for those rare cases in which 

methane and ethane comprise a disproportionately high amount of 

the organic compounds in the feed because these non-HAP 

compounds could be emitted and would be measured as THC. A 

previous study that compared total organic HAP to THC found that 

the organic HAP was 23 percent of the THC. We also analyzed 

additional data submitted during the development of this 

proposed rule that included simultaneous measure of organic HAP 

species and THC. Data were available from five tests, and the 

organic HAP averaged 24 percent of the THC. Based on these 

analyses, we are proposing an equivalent alternative emission 

limit for organic HAP species of 2 ppmv (i.e., 24 percent of 7

ppmv) for existing sources and 1 ppmvd for new sources. The 

specific organic compounds that will be measured to determine 

compliance with the alternative to the THC limit are benzene, 

toluene, styrene, xylene (ortho-, meta-, and para-), 

acetaldehyde, formaldehyde, and naphthalene. These were the 

organic HAP species that were measured along with THC in the 

emissions tests that were reviewed. Nearly all of these organic 

HAP species were identified in an earlier analysis of the 
66

organic HAP concentrations in THC in which the average 

concentration of organic HAP in THC was 23 percent.

Other Options Considered

We also examined the THC results to determine if 

subcategorization by type of kiln was warranted and concluded 

that the data were insufficient for determining that a 

distinguishable difference in performance exists based on the 

type of kiln. The top performing kilns in Table 4 include 

various types: wet, long dry, and preheater/precalciner kilns; 

older (wet kilns) and newer (precalciner kilns); and those with 

and without in-line raw mills. Although the type of kiln and 

the design and operation of its combustion system may have a 

minor effect on THC emissions, the composition of the feed and 

the presence of organic compounds in the feed materials 

apparently have a much larger effect. For example, organic 

compounds in the feed materials may volatilize and be emitted 

before the feed material reaches the high temperature combustion 

zone of the kiln where they would have otherwise been destroyed. 

We also evaluated creating separate subcategories for kilns 

with in-line raw mills and those without. With an in-line raw 

mill kiln, exhaust is used to dry the raw materials during the 

grinding of the raw meal. This drying step can result in some 

organic material being volatilized, thus increasing the THC 

emissions in the kiln exhaust. This means that kilns with in-
67

line raw mills would, on average, have higher emissions than 

kilns without in-line raw mills. The existence, or absence, of 

a raw mill is believed to have a distinct effect on emissions of 

THC, as one would expect. It is difficult to generalize that 

difference because the effect of the raw mill will vary based on 

the specific organic constituents of the raw materials. In 

tests at one facility, THC emissions, on average, were 35 

percent higher with the raw mill on than when the raw mill was 

off.24

This physical difference could justify subcategorization 

based on the presence of an in-line raw mill. There are also 

potential policy reasons for doing so. If we were not to 

subcategorize, this might discourage the use of in-line raw 

mills because, to meet a THC standard, in-line raw mill-equipped 

kilns would potentially have to utilize An RTO. Use of RTOs has 

various significant adverse environmental consequences, 

including increase in emissions of criteria pollutants, and 

significant extra energy utilization with attendant increases in 

greenhouse gas emissions.25

 

24 Email and attachments. B. Gunn, National Cement Company of 

Alabama to K. Barnett. USEPA. March 12, 2009. THC Mill 

on/Mill Off Variability

25 Summary of Environmental and Cost Impacts of Proposed 

Revisions to Portland Cement NESHAP (40 CFR Part 63, subpart 

LLL), April 15, 2009.
68

EPA has performed floor calculations for subcategories of 

kilns with and without in-line raw mills. The result of that 

calculation, where we were using the top 12 percent, was that 

the floor for kilns with in-line raw mills were actually lower

than those without, which is atypical: sources with in-line raw 

mills will typically have higher emissions because of the extra 

volatilization. We believe this anomalous result is the 

artifact of the small data set used to calculate the existing 

source MACT floor. Based on these results, we have concluded 

that the current data are not sufficient to allow us to 

subcategorize by the presence of an in-line raw mill, but would 

consider subcategorizing if additional data become available. 

We are specifically requesting comment on subcategorization by 

the presence or absence of an in-line raw mill and requesting 

data on this issue. 

2. Beyond the Floor Determination

Practices and technologies that are available to cement 

kilns to control emissions of organic HAP include raw materials 

material substitution, ACI systems and limestone scrubber and 

RTO. We do not think it is appropriate to develop a beyond-thefloor control option based on material substitution, the 

feasibility of which can only be determined on a site-by-site 

basis. We also think the proposed limits for THC will encourage 

 
69

kiln owners and operators to consider material substitution 

without the need for specific requirements to do so. 

We examined the use of either ACI systems or RTO (with a 

dedicated wet scrubber)26 as the basis for potential beyond-thefloor THC standards for existing and new sources. (We did not 

examine other beyond-the-floor regulatory options for existing 

or new sources because there are no controls that would, on 

average, generate a greater THC reduction than a combination of 

a wet scrubber/RTO.) These technologies are currently in 

limited use in the source category. At one facility, activated 

carbon is injected into the flue gas and collected in the PM 

control device. The activated carbon achieved a THC emissions

reduction of approximately 50 percent, and the collected carbon 

is then injected into the kiln in a location that insures 

destruction of the collected THC. The THC emissions from this 

facility are the highest for any facility for which we have data 

due to very unusual levels of organic material in the limestone 

and may not be representative of the performance that can be 

achieved by kilns with more typical THC emissions.27

ACI has been demonstrated in other source categories, such 

as various types of waste incinerators including municipal waste 

 

26 A wet scrubber is needed as a pretreatment step before gases 

are amenable to destruction in an RTO.

27 The same facility that uses ACI has a second control scheme 

for THC consisting of a wet scrubber/RTO in series. However, 

this system has not operated more that a few months at a time.
70

incinerators, to reduce dioxin/furan by over 95 percent (Chi and 

Chang, Environmental Science and Technology, vol 39, issue 20, 

October 2005; Roeck and Sigg, Environmental Protection, January 

1996). The actual performance of ACI systems on cement kiln THC 

emissions are expected to be less than that achieved on 

dioxin/furan emissions as kiln flue gases are a mixture of 

volatile and semi volatile organic compounds, which vary 

according to the organic constituents of raw materials. We have 

therefore conservatively estimated that ACI systems can reduce 

THC emissions by 75 to 80 percent. A second facility has a 

continuously operated limestone scrubber followed by an RTO.

This facility has been emission tested and showed volatile 

organic compound (VOC), which are essentially the same as THC, 

emission levels of 4 ppmv (at 7 percent oxygen), and currently 

has a permit limit for VOC of approximately 9 ppmv. The RTO has 

a guaranteed destruction efficiency of 98 percent of the 

combined emissions of carbon monoxide and THC. Based on this 

information, we believe this facility represents the best 

possible control performance to reduce THC emissions. 

In assessing the potential beyond-the-floor options for 

THC, we first determined that most existing kilns would have to 

install an ACI system for control of THC and/or mercury. A few 

kilns would be expected to install an RTO in order to get the 

THC proposed reductions. To evaluate the feasibility of beyond-
71

the-floor controls, we assumed that a kiln already expected to 

install an ACI system would install in series an RTO including a 

wet scrubber upstream of the RTO to protect the RTO. We 

estimated the costs and emission reductions for a 1.2 million 

tpy kiln as the cost effectiveness of the beyond-the-floor 

option would be similar for all kilns. Annualized costs for an 

additional RTO system would be $1.44 million per year. The 

quantity of THC leaving the upstream controls would be an 

estimated 18 tpy. At higher THC concentrations, for example 15 

ppmv and above, an RTO will have a removal efficiency of about 

98 percent. This mass of THC leaving the device upstream of and 

entering the RTO is equivalent to a THC concentration of about 3 

ppmv. At this low level, an RTO’s removal efficiency is 

expected to be no better than 50 percent. At a 50 percent 

control efficiency, the RTO would reduce THC emission by about 9 

tpy for a cost-effectiveness of approximately $157,000 per ton 

of THC removal. If the organic HAP fraction of the THC is 24 

percent, 2 tpy of organic HAP would be removed at a cost 

effectiveness of approximately $656,000 per ton of organic HAP 

removed. At a cost effectiveness of $157,000 per ton of THC and 

$656,000 per ton of organic HAP, we believe the cost of the 

additional emission reduction is not justified (this is a far 

higher level than EPA has deemed justified in other MACT 

standards, for example). In addition to the high cost of 
72

control, the additional energy requirements, 7.3 million kwh/yr 

and 87,800 MMBtu/yr, would be significant. Increased greenhouse 

gas emissions attributable to this energy use would be on the 

order of 12,000 tpy per source. The additional energy demands 

would also result in increased emissions of NOx (21 tpy), CO, 

(8.5 tpy), SO2 (28 tpy), and PM10 (1 tpy) per source. Because 

of the high costs and minimal reductions in THC and organic HAP 

as well as the secondary impacts and additional energy 

requirements, we are not selecting this beyond-the-floor option.

Therefore we are proposing for cement kilns an existing 

source THC emissions limit of 7 ppmvd and a new source limit of 

6 ppmvd, measured as propane and corrected to 7 percent oxygen. 

We are also proposing for an alternative organic HAP emissions 

limit of 2 ppmvd for existing kilns and 1 ppmvd for new kilns. 

THC Standard for Raw Material Dryers

Some plants may dry their raw materials in separate dryers 

prior to or during grinding. See 63 FR at 14204. This drying 

process can potentially lead to organic HAP and THC emissions in 

a manner analogous to the release of organic HAP and THC 

emissions from kilns when hot kiln gas contacts incoming feed 

materials. The methods available for reducing THC emissions (and 

organic HAP) is the same technology described for reducing THC 

emissions from kilns and in-line kiln/raw mills. Based on the 

similarity of the emissions source and controls, we are also 
73

proposing to set the THC emission limit of materials dryers at 7

ppmvd (existing sources) and 6 ppmvd (new sources). 

The current NESHAP has an emissions limit of 50 ppmvd for 

new greenfield sources. The limit is less stringent than the 

proposed changes in the THC emissions limits for new (as well as 

existing) sources. For that reason, we are proposing to remove 

the 50 ppmvd emissions limit for this rule. 

D. Determination of MACT for HCl Emissions from Major Sources

In developing the MACT floor for HCl, we collected over 40 

HCl emissions measurements from stack tests based on EPA Methods 

321 and 26. Studies have suggested that Method 26 is biased 

significantly low due to a scrubbing effect in the front half of 

the sampling train (see 63 FR at 14182). Because of this bias, 

we used the HCl data measured at 27 kilns using Method 321 in 

determining the proposed floors for existing and new sources. 

The data in ppmv corrected to 7 percent oxygen (O2) were ranked 

by emissions level and the top 12 percent (4 kilns) lowest 

emitting kilns identified.

30 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 

 

30 EPA notes that this floor determination, like the one for THC 

discussed in the preceding section, raises the issue of whether 

a floor determination for source categories with 30 sources or 

greater should be based on the performance of less than five 

sources. We solicited comment on that issue in the preceding 

section and repeat the solicitation here. 
74

floor. (Note that neither of these decisions significantly 

changed the final result of the floor calculation). These

emissions data are shown in Table 5. The average of the four 

lowest emitting kilns is 0.31 ppmvd. The variability for the 4 

lowest emitting kilns includes the run-to-run variability of 

three runs for each stack test and the variability across the 4 

lowest emitting kilns.

We calculated the MACT floor (2 ppmvd) based on the upper 

99th percentile UPL from the average performance of the 4 lowest 

emitting kilns and their variances as described earlier.

Table 5. HCl MACT Floor

Kiln HCl Emissions (ppmvd @ 7% O2)

1 0.02

2 0.02

3 0.22

4 0.97

MACT – Existing

Average 0.31

Variability (t*vT

0.5) 1.94

99th percentile 2

MACT – New

Average 0.02

Variability (t*vT

0.5) 0.12

99th percentile 0.1

MACT for new kilns is based on the performance of the 

lowest emitting kiln. The average HCl emissions for the lowest 

emitting kiln in this data set is 0.02 ppmv. Using the same 

statistical technique to apply run-to-run variability for that 
75

kiln’s emissions data, the HCl MACT floor for new kilns is 0.14

ppmvd at 7 percent O2.

For facilities that do not use wet scrubbers to meet the 

HCl limit, these standards would be based on a 30-day rolling 

average, consistent with the proposed use of CEMS (i.e.,

continuous measurements) for compliance. See section E below.

It should be noted that these emission limits are below the 

published detection level of the test method (EPA test method 

321). This issue is further discussed in section IV.I.

Beyond the Floor Standard for HCl

Based on the HCl emissions data, most kilns (both existing 

and new) would have to install limestone scrubbers in order to 

comply with the proposed floors for HCl. Scrubbers are expected 

to reduce HCl emissions by an average of at least 99 percent. 

Scrubbers added to reduce HCl emissions will also reduce 

emissions of SO2 and will remove oxidized mercury as well.

In examining a beyond-the-floor option for HCl, we 

evaluated the use of a more efficient HCl scrubber.

32 We assumed 

a spray chamber scrubber is sufficient to meet the MACT floor, 

 

32 We could identify no other add-on control options for acid gas 

removal that would achieve emissions reduction beyond the floor 

level of control. Other potentials options for reducing HCl 

emissions would involve changes in raw materials and fuels to 

lower chlorine-containing materials. The feasibility of 

switching raw materials, as discussed elsewhere, would involve 

site-specific evaluations for each cement facility and, 

therefore, cannot be applied uniformly throughout the industry.
76

and that scrubber is expected to remove HCl at an efficiency of 

99 percent (as just noted). However, we estimate that a packedbed scrubber would have removal efficiency greater than a spray 

chamber due to its increased surface area and opportunity for 

contact between the scrubbing liquid and the acid gases. We 

estimated the costs and emission reductions for a 1.2 million 

tpy kiln as the cost-effectiveness results would be similar for 

all kilns. Annual costs for a packed bed scrubber for a 1.2 

million tpy kiln would be approximately $2.2 million. 

Assuming a control efficiency of 99.9 percent, the 

incremental emission reduction using the beyond-the-floor 

packed-bed scrubber, that is, the reduction in HCl emissions 

after initial control by the MACT floor control (a spray chamber 

scrubber), would be about 2.4 tpy. At an annual cost of $2.2 

million, the cost effectiveness is $929,000 per ton of HCl 

removed. Adverse non-air quality impacts, such as energy costs, 

water impacts, and solid waste impacts would be expected to be 

similar for both the floor and beyond-the-floor level of 

control. Considering the high costs, high cost effectiveness 

and small additional emissions reduction (and adverse crossmedia impacts), we do not believe that a beyond-the-floor 

standard for HCl is justified. 

Other Alternatives for HCl standards
77

One option to HCl standards that we considered would be to 

set a standard that used SO2 as a surrogate for HCl. The reason 

to allow this option would be that some kilns already have SO2

controls and monitors. Acid gas controls that remove SO2 also 

remove HCl at equal or greater efficiency. However, we are not 

proposing this option because we have no data to demonstrate a 

direct link between HCl emissions and SO2 emissions – that is ,

it is unclear that ranking best HCl performers based on SO2

emissions would in fact identify lowest emitters or best 

controlled HCl sources. We are requesting comment on the 

efficacy of using SO2 as a surrogate for HCl, and data 

demonstrating that SO2 is or is not a good surrogate for HCl.

We also considered the possibility of proposing a healthbased standard for HCl. Section 112(d)(4) allows the 

Administrator to set a health based standard for a limited set 

of HAP: “pollutants for which a health threshold has been 

established”. EPA may consider that threshold, with an ample 

margin of safety, in establishing standards under section 112 

(d). In the 2006 rule, EPA relied on this authority in 

declining to establish a standard for HCl, finding that no 

source in the category would emit HCl at levels which would 

exceed the No Observed Effect Level for HCl with an ample safety 

margin. 71 FR at 76527-29. 
78

However, we are not proposing a health-based standard. This decision

is based on the fact that, in addition to the direct effect of reducing HCl 

emissions, setting a MACT standard for HCl is anticipated to result in a 

significant amount of control for other pollutants emitted by cement kilns, 

most notably SO2 and other acid gases, along with condensable PM, 

ammonia, and semi-volatile compounds. For example, the 

additional reductions of SO2 alone attributable to the proposed 

MACT standard for HCl are 105,000 tpy.34 These are substantial 

reductions considering the low number of facilities. Although 

MACT standards may only address HAP, not criteria pollutants, 

Congress fully expected MACT standards to have the collateral 

benefit of controlling criteria pollutants as well, and viewed 

this as an important benefit of the air toxics program. S. Rep. 

No. 101-228 101st Cong. 1st sess. at 172. It therefore is 

appropriate that EPA consider such benefits in determining 

whether to exercise its discretionary section 112 (d)(4) 

authority. 

It should also be noted that the CAA gives EPA the option 

to create a health-based standard for threshold pollutants. 

Generally, without adequate evidence that a pollutant may be a 

carcinogen (and therefore likely being a non-threshold 

pollutant), EPA has assumed there is an effect threshold. For 

HCl, the Integrated Risk Information System (IRIS) indicates 

 

34 Summary of Environmental and Cost Impacts of Proposed 

Revisions to Portland Cement NESHAP (40 CFR Part 63, subpart 

LLL), April 15, 2009.
79

that EPA has derived an inhalation reference concentration for 

HCl of 20 μg/m3. Long-term exposure at or below this level is

believed to be without appreciable risk of chronic non-cancer 

effects. However, HCl has not been evaluated by the IRIS 

program to determine its carcinogenicity. Additionally, the 

International Agency for Research and Cancer (IARC) found HCl 

not classifiable as a carcinogen to humans due to inadequate 

evidence in humans and lab animals.37 We request comment on the 

evidence necessary to determine whether a HAP, in this case HCl, 

is or is not a threshold pollutant, and any additional data on 

the carcinogenicity of HCl, and other information on HCl health 

and environmental38 effects we should consider. Commenters 

should also address the issue of other environmental benefits 

which might result from control of HCl at a MACT level, 

including control of other acid gases and control of secondary 

PM (i.e., PM condensing from acid gases). We will consider 

these comments in making an ultimate determination as to whether 

to adopt a health-based standard for HCl.

Finally, we determined that even if we opted to set a 

health based standard, we would still need to set a numerical 

 

37 (see http://www.inchem.org/documents/iarc/vol54/03-

hydrochloric-acid.html). 

38 See S. Rep. No. 101-228, 101st Cong. 1st sess. at 175 

indicating that EPA is to consider environmental effects as well 

as health effects under section 112 (d)(4).
80

emission limit given that section 112(d)(4) still requires that 

an actual emission standard be in place. In order to determine 

this level, we conducted a risk analysis of 68 facilities using 

a screening level dispersion model (AERSCREEN). Utilizing site 

specific stack parameters and worst-case meteorological 

conditions, AERSCREEN predicted the highest ground level 

concentration surrounding each facility. The results of this 

analysis indicated that an emission limit of 23 ppmv or less 

would result in no exceedances of the NOEL for HCl with a margin 

of safety. Although, as discussed above, EPA is not proposing a 

health-based standard, EPA solicits comment on the level of 23 

ppmv (as a not-to-exceed standard) should EPA decide to pursue 

the option of a health-based standard.

E. Determination of MACT for PM Emissions from Major and Area 

Sources

Existing and new major sources are presently subject to a 

PM limit of 0.3 lb/ton of feed which is equivalent to 0.5 lb/ton 

clinker. EPA is proposing to amend this standard, and also is 

proposing PM standards for existing and new area source cement 

kilns. In all instances, PM serves as a surrogate for 

nonvolatile metal HAP (a determination upheld in National Lime 

Ass’n, 233 F. 3d at 637-39). EPA is proposing to revise these 

limits because they do not appear to represent MACT, but rather 

a level which is achievable by the bulk of the industry. See 63 
81

FR at 14198. This is not legally permissible. Brick MACT, 479 

F. 3d at 880-81.

We compiled PM stack test data for 45 kilns from the period 

1998 to 2007. EPA ranked the data by emissions level and the 

lowest emitting 12 percent, 6 kilns, was used to develop the 

proposed existing source MACT floor.

As for the previous floors, we calculated the variances of 

each kiln and accounted for variability by determining the 99th

percentile UPL as described earlier. The average performance 

for each of the lowest emitting kilns was generally based on the 

average of 3 runs which comprise a stack test. Consequently, 

the variability represents the short term variability at a kiln 

(e.g., a 3 hour stack test period) and the variability across 

the 6 lowest emitting kilns. (This analysis is consistent with 

the way we would propose to determine compliance, i.e., conduct 

3 runs to perform a stack test.) For the lowest emitting kiln

(whose performance was used to establish the new source floor), 

there were only 3 runs with results that were relatively close 

together, which is inadequate to estimate the kiln’s long term 

variability. However, we know the 6 lowest emitting kilns are 

equipped with fabric filters that are similar with respect to 

performance because they are similar in design and operation, 

and the larger dataset provides a much better estimate of the 

variability associated with a properly operated fabric filter. 
82

Consequently, for the proposed new source floor, we used the 

average performance of the lowest emitting kiln and the 

variability associated with the best fabric filters to assess 

the best performing kiln’s variability.

The emissions for the top six kilns ranged from 0.005 to 

0.008 lb/ton clinker. Accounting for variability as described 

above, we calculated an existing source MACT floor of 0.085

lb/ton clinker. For new kilns, the limit is based on the best 

lowest emitting kiln, which has emissions of 0.005 lb/ton 

clinker. Accounting for variability results in a calculated new 

source MACT floor of 0.080 lb/ton clinker. The PM emissions 

data are summarized in Table 6.

Table 6. PM MACT Floor

Kiln PM Emissions (lb/ton clinker)

1 0.005

2 0.0075

3 0.0075

4 0.0081

5 0.0108

6 0.0232

MACT - Existing

Average 0.010

Variability (t*vT

0.5) 0.075

99th percentile 0.085

MACT - New

Average 0.005

Variability (t*vT

0.5) 0.075

99th percentile 0.080

EPA is also proposing to set a PM standard based on MACT 

for existing and new area source cement kilns. Portland cement 
83

kilns are a listed area source category for urban HAP metals 

pursuant to section 112(c)(3), and control of these metal HAP 

emissions (via the standard for the PM metal surrogate) is 

required to ensure that area sources representing 90 percent of 

the area source emissions of urban metal HAP are subject to 

section 112 control, as required by section 112(c)(3). EPA is 

proposing that this standard reflect MACT, rather than GACT, 

because there is no essential difference between area source and 

major source cement kilns with respect to emissions of either 

HAP metals or PM. A common control strategy consequently is 

warranted for these emissions. Thus, the factors that determine 

whether a cement kiln is major or area are typically a function 

of the source’s HCl or formaldehyde emissions, rather than its 

emissions of HAP metals. As a result, there are kilns that are 

physically quite large that are area sources, and kilns that are 

small that are major sources. Both large and small kilns have 

similar HAP metal and PM emissions characteristics and controls. 

We thus have included all cement kilns in the floor calculations 

for the proposed PM standard, and have developed common PM 

limits based on MACT for both major and area sources. 

Consideration of Beyond-the-Floor Standards

There is very little difference in the proposed floor 

levels for PM for either new or existing sources, and we believe 

that a well-performing baghouse represents the best performance 
84

for PM. To evaluate beyond-the-floor controls, we examined the 

feasibility of replacing an existing ESP or baghouse with a new 

baghouse equipped with membrane bags which might result in a 

slightly better performance for PM (reflected in the modest 

increment between the proposed floors for new and existing 

sources). We estimated the costs and emission reductions for a 

1.2 million tpy kiln. The cost-effectiveness results will be 

similar for all kilns. Under the MACT floor, baseline emissions 

of 0.34 lb/ton of clinker are reduced to 0.085 lb/ton of 

clinker, a reduction in PM emission of 51 tpy. Further reducing 

emissions down to the proposed PM limit for new sources would 

incrementally reduce emissions by an additional 3 tpy. The 

annualized cost of a baghouse with membrane bags would be $1.73 

million per year, or a cost effectiveness of $576,000/ton of PM

(far greater than any PM reduction EPA has ever considered 

achievable under section 112(d)(2) or warranted under other 

provisions of the Act which allow consideration of cost). 

Assuming that the metal HAP portion of total PM is 1 percent, 

the cost effectiveness would be about $58 million per ton of 

metal HAP. Based on these costs and the small resulting emission 

reductions, we believe a PM beyond-the-floor standard is not 

justified for existing sources and not technically feasible for 

new sources.

Other Standards for PM
85

Emissions from fabric filters or ESP are typically measured 

as a concentration (grains per dry standard cubic feet) and then 

converted to the desired format using standard conversions 

(54,000 dry cubic feet per minute of exhaust gas per ton of 

feed, 1.65 tons of feed per ton of clinker). All of the data 

used to set the proposed PM emissions limit were converted in 

that fashion. Therefore, the basis of the proposed PM standard 

is actually a concentration level. There are certain cases 

where this conversion must be adjusted, however. Some kilns and 

kiln/in-line raw mills combine the clinker cooler gas with the 

kiln exhaust and send the combined emissions to a single control 

device. There are significant energy savings (and attendant 

greenhouse gas emission reductions) associated with this 

practice, since heat can be extracted from the clinker cooler 

exhaust. However, there need to be different conversion factors 

from concentration to mass per unit clinker. In the case where 

clinker cooler gas is combined with the kiln exhaust the 

standard would need to be adjusted to allow for the increased 

gas flow. If this allowance is not made, then the effective 

level of the PM standard would be reduced (the result being that 

the proposed standard would not properly reflect best performing 

kilns’ performance, and also discouraging use of a desirable 

energy efficiency measure). Therefore, we are proposing that 

facilities that combine the kiln and clinker cooler gas flows 
86

prior to the PM control would be allowed to convert the 

equivalent concentration standards (which are 0.0067 or 0.0063

for new and existing sources, respectively) to a lb/ton clinker 

standard using their combined gas flows (dry standard cubit feet 

per ton of feed). It should be noted that this provision will 

not result in any additional PM emissions to the atmosphere 

compared to the same kiln if it did not combine the clinker 

cooler and kiln exhaust, and may actually decrease emissions 

slightly due to improvements in overall process efficiency. 

In addition to proposing to amend the PM standard for kilns 

we are also proposing to similarly amend the PM emissions limit 

for clinker coolers. Fabric filters are the usual control for 

both cement kilns and clinker coolers. As EPA noted in our 

proposed revision to Standards of Performance for Portland 

Cement Plants (73 FR 34078, June 16, 2008) we believe that the 

current clinker cooler controls can meet the same level of PM 

control that can be met by the cement kiln. Therefore, we are 

proposing as MACT the same PM emissions limits for both clinker 

coolers and kilns. 

In sum, because we believe that the costs of a beyond-thefloor standard for PM are not justified, we are proposing a PM 

standard for existing kilns and clinker coolers of 0.085 lb/ton 

of clinker, and for new kilns and clinker coolers of 0.080

lb/ton of clinker.
87

F. Selection of Compliance Provisions

For compliance with the mercury emissions standards we are 

proposing to require CEMS (either instrument based or sorbent 

trap based). As we have previously noted, we do not believe 

that short term emission tests provide a good indication of long

term mercury emissions. We considered the option of measuring

and analyzing the raw materials, as was done to gather the data

used to develop the proposed standards. However, that data 

gathering was done based on a daily analysis of all inputs to 

the kiln. If we were to make that the compliance option and 

require daily analyses, the cost would be comparable to the cost 

of a mercury monitor. If we were to allow less frequent 

analyses to reduce costs, then we are concerned that the 

accuracy may be reduced (and the standard would no longer be 

implemented in the same manner as it was developed). In 

addition, in order to meet the proposed mercury emission limits, 

we anticipate that many facilities will install add-on controls, 

which will create another variable that would make the 

measurement of mercury inputs as a surrogate for a continuous

stack measurement less accurate. In order to determine an 

outlet emissions rate based on input measurements, the control 

device would have to be tested under various operating 

conditions to insure that the removal efficiency could be 

accurately calculated, and parametric control device monitoring
88

would be required. Given issues related to input monitoring, 

and the cost associated with control device monitoring, plus a 

desire to implement the standard in a manner matching its means 

of development, we believe that a continuous mercury measure at 

the stack is the preferred option, and are proposing that 

sources demonstrate compliance with mercury monitors meeting the 

requirements of PS-12A or PS-12B.

Generally, we propose and promulgate monitoring system 

performance specifications and performance test methods in 

accordance with their development, independent of publication of 

source category emissions control regulations. There are 

circumstances dictating that we publish such measurement 

procedures and requirements simultaneously with an emissions 

regulation because of integral technical relationships and 

because such a combination is convenient and cost-effective.

Such combined publication also allows commenters to prepare 

comprehensive comments on not only the performance 

specifications or test methods but also on their specific 

applications. In today's notice, we propose to amend 40 CFR 

part 60, appendix B by adding Performance Specification 12A –

Specifications and Test Procedures For Total Vapor Phase Mercury 

Continuous Emission Monitoring Systems in Stationary Sources and

Performance Specification 12B - Specifications and Test 
89

Procedures For Monitoring Total Vapor Phase Mercury Emissions 

from Stationary Sources Using a Sorbent Trap Monitoring System.

We published versions of these performance specifications 

with the electric utility mercury MACT rule. On March 14, 2008, 

the DC Circuit Court issued a mandate to vacate the Clean Air 

Mercury Rule which included that MACT rule clouding the status 

of these measurement procedures. We are republishing the 

performance specifications today to clarify the status of those 

procedures particularly in their applicability to source 

categories in addition to coal-fired electric utilities. In 

this case, our analyses show that mercury emissions from 

portland cement kilns exhibit most, if not all, of the same 

physical and chemical characteristics as mercury emissions from 

coal-fired electric utilities. Since Performance Specifications 

12A and 12B are suitable for use in measuring emissions from 

portland cement kilns, we also believe that these measurement 

procedures with minor revision also apply to other sources. We 

believe that the simultaneous proposal of these performance 

specifications revised to reflect broad applicability with 

today's Portland Cement MACT proposal is appropriate. The 

combined notice of proposals is cost-effective, and affords 

commenters the ability to provide comprehensive comments."

We are aware that there are currently no cement kilns in 

the U.S. that have continuous mercury monitors. However, there 
90

are numerous utility boilers that have certified mercury CEMS. 

We see no technical basis to say that continuous mercury 

monitors will not work as well on a cement kiln as they do on a 

utility boiler. In addition, there are 34 cement kilns that 

have operating continuous mercury monitors in Germany.43

For demonstrating compliance with the proposed THC 

emissions limit we are proposing the use of a CEMS meeting the 

requirements of PS-8A. This requirement already exists for new 

kilns. There are existing kilns that already have THC CEMS, and

indeed, EPA used CEMS data from these kilns as the basis for the 

proposed standards. As previously noted, changes in raw 

materials can materially affect THC emissions without any 

obvious indication that emissions have changed. For this 

reason, and to be consistent with the means by which EPA 

developed the proposed standard, we believe (subject to 

consideration of public comment) a CEMS is necessary to insure 

continuous compliance.

If a source chooses to comply with the alternative organic 

HAP emissions limit, rather then the THC limit, we are not 

planning to propose the use of a continuous monitor to directly 

measure organic HAP because organic HAP monitors are not 

 

43 Email and attachment. M. Bernicke, Federal Environment Agency

to A. Linero, Florida Department of Environmental Protection. 

February 8, 2009.
91

available for this application. We are proposing to use EPA 

Method 320 to determine the actual organic HAP content of the 

THC at a specific facility. If Method 320 indicates compliance 

with the alternative organic HAP standard, then the THC 

emissions measures using a CEMS would become that site’s THC 

limit (assuming that the THC emissions measured during the 

testing exceed the MACT floor values of 7 ppmvd for existing 

sources and 6 ppmvd for new sources). 

For demonstrating compliance with the proposed PM emissions 

limit, we are proposing the installation and operation of a bag 

leak detection system, along with stack testing using method 

conducted at a frequency of five years. If an ESP is used for 

PM control an ESP predictive model to monitor the performance of 

ESP controlling PM emissions from kilns would be required, as 

well as a stack performance test conducted at a frequency of 

five years. As an alternative a PM CEMS that meets the 

requirements of PS-11 may be used. We are also proposing to 

eliminate the current requirement of using an opacity monitor to 

demonstrate continuous requirement with a PM standard for kilns 

and clinker coolers.

We previously proposed use of bag leak detection systems 

for PM as part of our review of the Portland Cement Standards 

for Performance under section 111 of the Act (73 FR 34072, June 

16, 2008). Our rationale for extending the requirement to 
92

existing kilns is that given the stringent level of the proposed 

PM emissions limits we do not believe that opacity is an 

accurate indicator of compliance with the proposed PM emissions 

limit. In addition, we are removing the opacity standard and 

opacity continuous monitoring requirements for any source that 

uses a PM CEMS or bag leak detector to determine compliance with 

a PM standard. (Some opacity requirements, such as those for 

materials handling operations, will remain in place). 

For demonstrating compliance with the HCl emissions limit 

we are proposing the use of a CEMS that meets the requirements 

of PS-15 if the source does not use a limestone wet scrubber for 

HCl control. As with mercury and THC, HCl emissions can be 

significantly affected by inputs to the kiln without any visible 

indications. For this reason we believe that a continuous 

method of compliance is warranted. If the source uses a 

limestone wet scrubber for HCl control, we believe that HCl 

emissions will be minimal even if kiln inputs change because

limestone wet scrubbers are highly efficient in removing HCl. 

For this reason we are proposing to require sources using a 

limestone wet scrubber to perform an initial compliance test 

using EPA Test Method 321, and to test every 5 years thereafter. 

These EPA Test Method 321 testing requirements would also apply 

to sources using CEMS. In addition, for sources with in-line 

raw mills that are not using a wet scrubber for HCl control, we 
93

are proposing to require testing with raw mill on and raw mill 

off. Our review of the available data where a kiln was tested 

with raw mill on/raw mill off indicated that the change in raw 

mill operating conditions had a significant influence in HCl 

emissions. We are specifically requesting comment on our 

assumption that a wet scrubber will consistently maintain a low 

level of HCl emissions, even if feed conditions change, and thus 

it is appropriate to use a short term performance test rather 

then a continuous monitor for kilns that install wet scrubbers.

One option we considered would be to require SO2 monitoring 

in lieu of HCl monitoring. The reason to allow this option 

would be that some kilns already have SO2 monitors, and this 

monitoring technology is less expensive and more mature than HCl 

monitors. If a source is using a wet scrubber for HCl control, 

then indication that the scrubber is removing SO2 are also a 

positive indications that HCl is being removed. However, we are 

not proposing this because we have no data to demonstrate a 

direct link between HCl emissions and SO2 emissions. For 

example, if a source has a scrubber-equipped kiln and notes an 

SO2 emissions increase, is the increase due to a drop off in 

scrubber performance or to an increase in sulfur compounds in 

the raw materials? If it is simply a change in raw materials

sulfur content, then the change may have no relevance to HCl 

emissions. If the SO2 emission increase is due to a reduction in 
94

scrubber efficiency, then the change in SO2 emission might mean 

that HCl emission have changed. We are requesting comment on 

the efficacy of using SO2 as a surrogate for HCl for purposes of 

monitoring compliance, and data demonstrating whether SO2 is a 

good surrogate for HCl for this purpose. 

One issue in using a CEMS to measure compliance with these 

proposed standards is whether the use of a continuous monitor 

results in an increase in the stringency of the standard, if 

that standard was developed based on short term emissions tests 

or other data and is a not-to-exceed standard. Mercury data 

were obtained from thirty daily samples of fuel and raw 

materials plus statistical techniques to account for further 

variability in inputs, operation, and measurement. The proposed 

hydrogen chloride emissions limit were derived using statistical 

techniques to account for variability in components such as fuel 

and raw material, process operation, and measurement procedures. 

The proposal would require direct, continuous measurement of 

mercury and, for those facilities not using a wet scrubber as a 

control device, hydrogen chloride. Compliance with these 

emissions limits for these facilities is determined by assessing 

the thirty day average emissions with the appropriate emissions 

limit. With respect to mercury, as explained in section 

above, not only do continuous monitoring and 30-day averaging 

accord well with the means used to gather these underlying data, 
95

but continuous monitoring and 30-day averaging are needed 

because cement kilns do not emit mercury in relatively equal 

amounts day-by-day but, due to the mill-on/mill-off phenomenon, 

in varying small and large amounts. With respect to hydrogen 

chloride, use of a thirty day average provides a way to account 

for the potential short term variability inherent in values 

obtained from continuous data collection and analysis, so that 

CEM-based compliance, in combination with 30-day averaging, does 

not make the proposed standard more stringent than a not-toexceed standard based on stack testing. Therefore, subject to 

consideration of public comment, we believe the use of 

continuous monitoring techniques for mercury and HCl, in 

combination with 30-day averaging times, is appropriate.

G. Selection of Compliance Dates

For existing sources we are proposing a compliance date of 

3 years after the promulgation of the new emission limits for 

mercury, THC, PM, and HCl take effect. This is the maximum time

period allowed by law. See section 112(i)(3)(A). We believe a 

3 year compliance period is justified because most facilities 

will have to install emissions control devices (and in some 

cases multiple devices) to comply with the proposed emissions 

limits. 

In the December 2006 rule amendments we included operating 

requirements relating to the amount of cement kiln dust wasted 
96

versus dust recycled, and also a requirement that the source 

certify that any fly ash used as a raw material did not come 

from a boiler using sorbent to remove mercury from the boiler’s 

exhaust. The removal of these requirements would take effect 

once the affected source is required to comply with a numerical 

mercury limit. 

For new sources, the compliance date will be the date of 

publication of the final rule or startup, whichever is later. 

In determining the proposal date that determines if a source is 

existing or new, we are retaining the date of December 5, 2005

for HCl, THC, and mercury, i.e., any source that commenced 

construction after December 5, 2005, is a new source for 

purposes of the emission standards changed in these amendments. 

For PM, we are proposing that the date that determines if a 

source is existing or new will be [INSERT THE DATE OF PUBLICTION 

OF THESE AMENDMENTS IN THE FEDERAL REGIATER]. 

In proposing this determination, we considered three 

possible dates, including March 24, 1998; December 5, 2005; and 

the proposal date of these amendments. Section 112 (a) (4) of 

the Act states that a new source is a stationary source if “the 

construction or reconstruction of which is commenced after the 

Administrator first proposes regulations under this section 

establishing an emissions standard applicable to such source”. 

“First proposes” could refer to the date EPA first proposes 
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standards for the source category as a whole, or could refer to 

the date the agency first proposes standards under a particular 

rulemaking record. The definition is also ambiguous with regard 

to whether it refers to a standard for the source as a whole, or 

to a HAP-specific standard (so that there could be different new 

source standards for different HAP which are regulated at 

different times). 

We believe that the section 112 (a)(4) definition can be 

read to apply pollutant-by-pollutant, and that the provision 

applies to the rulemaking record under which a standard is 

developed. The evident intent of the definition plus the 

substantive new source provisions is that it is technically more 

challenging and potentially more costly to retrofit a control 

system to an existing source than to incorporate controls when a 

source is initially designed. Consequently, new source 

standards should apply to sources which are being newly 

constructed or reconstructed in fact. See 71 FR at 76540-541. 

If, for example, we were to choose March 24, 1998, as the date 

to delineate existing versus new sources, then numerous kilns 

that would be required to meet new source standards would have 

to retrofit controls that they could not have reasonably 

anticipated at the time the source was originally designed.46

 

46 Two other provisions of the Act are pertinent here as well. 

Section 112(i)(1) requires preconstruction review for, among 
98

We also considered selecting the proposal date of these 

amendments as the date that delineates new and existing sources 

but, for HAP other than PM, rejected that option. The mercury 

and THC standards being proposed here arise out of the 

rulemaking proposed on December 5, 2007. This notice is issued 

in response to petitions for reconsideration of the standards 

from that rulemaking. The proposed standard for HCl likewise 

arises out of the December 2007 rulemaking and its 

reconsideration, and EPA proposed standards for HCl in that 

rulemaking. See 70 FR at 72335-37. Thus, it is reasonable to 

view the December 2005 proposal as the date on which EPA first 

proposed standards for HCl as part of this rulemaking. 

For PM, the choices are the 1998 date on which EPA proposed 

PM standards, or the date of this proposal (the first date EPA 

proposed revision to the PM standard, based on a new rulemaking 

 

other sources, all new sources subject to a new source standard. 

Such preconstruction review would be impossible if new sources 

included sources which began operation pursuant to an historic 

new source standard, which standard was later amended. Such a 

source would, of course, have already been operating. In 

addition, section 111(a)(2) defines “new source” as a stationary 

source “the construction or reconstruction of which is commenced 

after the publication of regulations (or, if earlier, proposed 

regulations” prescribing a standard of performance under this 

section”. Such standard must be reviewed periodically at least 

every 8 years. EPA’s longstanding interpretation of this 

provision is that only sources commencing construction (or which 

are reconstructed) after the date of a revised new source 

performance standard would be subject to that revised standard. 

There seems no evident reason to interpret the section 112 

(a)(4) definition differently from the section 111(a)(2) 

definition.
99

record). Subject to consideration of public comment, we believe 

the appropriate date is the date of this proposal. See 71 FR at

76540-41 (applying new source standards to sources which began 

operation many years in the past is inconsistent with idea that 

new source standards may be more stringent because they can be 

implemented at time of initial design of the source, thus 

avoiding retrofit expense). 

We are establishing a compliance date for the THC emissions 

limit for new sources as December 21, 2009 or the effective date 

of these amendments, whichever is later. A new source which 

commenced construction after December 2, 2005 and before 

December 20, 2006 would have three years from the date of 

publication of the final amendments to comply. See section 

112(i)(2).

H. Discussion of EPA’s Sector Based Approach for Cement 

Manufacturing 

What is a Sector-Based Approach?

Sector-based approaches are based on integrated assessments 

that consider multiple pollutants in a comprehensive and 

coordinate manner to manage emissions and CAA requirements. One 

of the many ways we can address sector-based approaches is by 

reviewing multiple regulatory programs together whenever 

possible. This approach essentially expands the technical 

analyses on costs and benefits of particular technologies, to 
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consider the interactions of rules that regulate sources. The 

benefit of multi-pollutant and sector-based analyses and 

approaches include the ability to identify optimum strategies, 

considering feasibility, costs, and benefits across all

pollutant types – criteria, toxics and others -- while 

streamlining administrative and compliance complexities and 

reducing conflicting and redundant requirements, resulting in 

added certainty and easier implementation of control strategies 

for the sector under consideration. 

Portland Cement Sector-Based Approach

Multiple regulatory requirements currently apply to the 

cement industry sector. In order to benefit from a sector-based 

approach for the cement industry, EPA analyzed how the NESHAP 

under reconsideration relates to other regulatory requirements 

currently under review for portland cement facilities. The 

requirements analyzed affect HAP and/or criteria pollutant 

emissions from cement kilns and cover the NESHAP 

reconsideration, area source NESHAP, NESHAP technology review 

and residual risk, and the New Source Performance Standard 

(NSPS) revision. The results of our analyses are described 

below. 

The first relationship is the interaction between the 

NESHAP THC standard and the co-benefits for VOC and carbon 

monoxide (CO) control. The THC limit for new sources in the 
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NESHAP will also control VOC and CO to the limit of technical 

feasibility. For this reason the proposed NSPS relies on the 

THC NESHAP limit for new sources to represent best demonstrated 

technology (BDT) for VOC and CO for this source category. See 

73 FR 34082.

Another interaction relates to the more stringent PM 

emission limit being proposed under the NESHAP reconsideration. 

As noted, there is a legal requirement to regulate listed urban 

HAP metals from area source cement kilns under section 

112(c)(3), and we are proposing PM standards for area source 

cement kilns pursuant to that obligation.47 In addition, we are 

required under CAA section 112(f) to evaluate the residual risk 

for toxic air pollutants emitted by this source category and to 

perform a technology review for this source category under 

section 112(d)(6). Revisions to the PM standard for new and 

existing major sources under the NESHAP will maximize 

environmental benefits due to the achievement of greater PM 

emission reductions and will also reduce the possibility for 

additional control requirements as we consider the implication 

these revisions have in developing future requirements under 

residual risk and technology review increasing certainty to this 

sector. 

 

47 Memo from K. Barnett, EPA to Sharon Nizich, EPA. Extension of 

Portland Cement NESHAP PM limits to Area Sources. May 2008.
102

To reduce conflicting and redundant requirements for the 

cement industry regarding the control of PM emissions, EPA is 

proposing to place language in both the NESHAP and the NSPS 

making it clear that if a particular source has two different 

requirements for the same pollutant, they are to comply with the 

most stringent emission limit, and are not subject to the less 

stringent limit. 

Another issue being addressed as part of our cement sector 

strategy is condensable PM. Particulate emissions consist of 

both a filterable fraction and a condensable fraction. The 

condensable fraction exists as a gas in an exhaust stream and 

condenses to form particulate once the gas enters the ambient 

air. In this rulemaking, AP-42 emission factors were used to 

calculate emission reductions of PM2.5 filterable due to the PM 

standard.48 There are insufficient data to assess if the cement 

industry is a significant source of condensable PM. The 

measurement of condensable PM is important to EPA's goal of 

reducing ambient air concentrations of PM2.5. While the Agency 

supports reducing condensable PM emissions, the amount of 

condensable PM captured by Method 5 (the PM compliance test 

method specified in the NSPS) is small relative to methods that 

specifically target condensable PM, such as Method 202 (40 CFR 

 

48 AP 42, Fifth Edition, Volume I Chapter 11: Mineral Products 

Industry. Section 11.6 January 1995 p. 11.6-15
103

part 51, Appendix M). Since promulgation of Method 202 in 1991, 

EPA has been working to overcome problems associated with the 

accuracy of Method 202 and plans to promulgate improvements in 

the future. In order to assist in future sector strategy 

development, we are considering any data available on the levels 

of condensable PM emitted by the cement industry; any 

condensable PM emission test data collected using EPA 

Conditional Method 39, EPA Method 202 (40 CFR part 51, Appendix 

M), or their equivalent, factors affecting those condensable PM 

emissions, and potential controls. 

Another benefit of evaluating regulatory requirements 

across pollutants in the context of a sector approach is 

addressing the relationship between the regulatory requirements 

for SO2, mercury, and HCl emissions. Although SO2 emission 

reductions would be required in the proposed NSPS, mercury and 

HCl emissions reduction are required in the Portland Cement 

NESHAP reconsideration. The integrated analysis of these 

regulatory requirements showed that alkaline wet scrubbers 

achieve emission reductions for SO2, mercury, and HCl from cement 

kilns. This control technology maximizes the co-benefits of 

emission reductions while minimizing cost. For example, a new 

facility that under the NSPS determines a moderate level of SO2

reduction might consider using a lime injection system because 

it is lower cost. However, if the same facility would have to 
104

use some type of add-on control to meet the NESHAP new source 

mercury and/or HCl emission limits, instead of considering each 

standard in isolation, would determine that the cheapest overall 

alternative might be to use a wet scrubber for controlling SO2, 

mercury, and/or HCl. By coordinating requirements at the same 

time, the facility can determine which control technology 

minimizes the overall cost of air pollution control and can 

avoid stranded costs associated with piecemeal investments in 

individual control equipment for SO2, mercury, and/or HCl.

The integrated sector-based analysis for the cement 

industry also showed that SO2 emission reductions from existing 

sources are possible as co-benefits if wet scrubbers are 

employed to control either mercury and/or HCl from existing 

sources under the NESHAP. We evaluated the co-benefits of the 

use of wet scrubbers in reducing SO2 and the effects on PM2.5 and 

PM2.5 nonattainment areas (NAA), including the co-benefits of 

reducing SO2 in mandatory Federal Class I areas (Class I 

areas)50.

Another interaction addressed in the context of the sector 

approach is monitoring requirements. To ensure that our sector 

 

50 Areas designated as mandatory Class I Federal areas are those 

national parks exceeding 6000 acres, wilderness areas and 

national memorial parks exceeding 5000 acres, and all 

international parks which were in existence on August 7, 1977. 

Visibility has been identified as an important value in 156 of 

these areas. See 40 CFR part 81, subpart D. 
105

strategy reduces administrative and compliance complexities 

associated with complying with multiple regulations, our 

rulemaking recognizes that where monitoring is required, methods 

and reporting requirements should be consistent in the NSPS and 

NESHAP where the pollutants and emission sources have similar 

characteristics. 

New Source Review and the Cement Sector-based Approach

The proposed MACT requirements for cement facilities have a 

potential to result in emissions reductions of air pollutants 

that are regulated under the CAA’s major new source review (NSR) 

program. Specifically, operating a wet scrubber to meet MACT 

requirements for mercury and/or HCl at a portland cement plant 

has the added environmental benefit of reducing large amounts of 

SO2, a regulated NSR pollutant. For a typical wet scrubber, with 

a 90 percent removal efficiency for SO2, this could result in an 

annual reduction of thousands of tons of SO2 from an uncontrolled 

kiln (reduction will vary greatly depending on the type and age 

of the kiln, sulfur content of feed materials, and fuel type). 

These collateral SO2 and other criteria pollutant emissions 

reductions resulting from the application of MACT may be 

considered for “netting” and “offsets” purposes under the major 

NSR program.

The term “netting” refers to the process of considering 

certain previous and prospective emissions changes at an 
106

existing major source over a contemporaneous period to determine 

if a “net emissions increase” will result from a proposed 

modification. If the “net emissions increase” is significant, 

then major NSR applies. Section 173(a)(1)(A) of the Act 

requires that a major source or major modification planned in a 

nonattainment area obtain emissions offsets as a condition for 

approval. These offsets are generally obtained from existing 

sources located in the vicinity of the proposed source and must 

offset the emissions increase from the new source or 

modification and provide a net air quality benefit. 

An emissions reduction must be “surplus,” among other 

things, to be creditable for NSR netting and offset purposes. 

Typically emission reduction required by the CAA are not 

considered surplus. For example, emissions reductions already 

required by an NSPS, or those that are relied upon in a State 

implementation plan (SIP) for criteria pollutant attainment 

purposes (e.g., Reasonable Available Control Technology, 

reasonable further progress, or an attainment demonstration), 

are not creditable for NSR offsets (or netting) since this would 

be “double counting” of the reductions. Also, any emissions 

reductions already counted in previous major modification 

“netting” may not be used as offsets. However, emissions 

reductions that are in excess of, or incidental to the MACT 

standards, are not precluded from being surplus even though they 
107

result from compliance with a CAA requirement. Therefore, 

provided such reductions are not being double counted, they may 

qualify as surplus and can either be used either as netting 

credits at the source or be sold as emissions offsets to other 

sources in the same non-attainment area provided the reductions 

meet all other otherwise applicable CAA requirements for being a 

creditable emission reduction for use as an offset or for 

netting purposes. 

Since SO2 is presumed a PM2.5 precursor in all prevention of 

significant deterioration and nonattainment areas unless a state 

specifically demonstrates that it is not a precursor, SO2 may be 

used as a emission reduction credit for either SO2 or PM2.5, at an 

offset ratio is 40-to-1 (40 tons of SO2 to 1 ton of PM2.5) See 72 

FR 28321-28350 (May 16, 2008).

Given that many states have concerns over a lack of direct 

PM2.5 emissions offsets for areas that are designated 

nonattainment for PM2.5, cement plants that generate creditable 

reductions of SO2 from applying MACT controls may realize a 

financial benefit if they can sell the emissions credits as SO2

and/or PM2.5 offsets. While it is difficult to quantify the 

exact financial benefit, since offset prices are market driven 

and vary widely the U.S., we know that prices for PM2.5 emissions 

credits can reach $40,000 in some nonattainment areas, and may 

still be higher in others. For the sake of approximation, using 
108

$20,000 for an average price per ton of a PM2.5 offset, a cement 

plant that creates a 2,000 tons per year reduction in SO2 can 

potentially sell the emissions credits for as much as $1,000,000 

per year (i.e., 2000 tpy ÷ 40_ratio × $20,000/ton), as long as 

the reductions are creditable and surplus.

National Ambient Air Quality Standards

Portland cement kilns emit several pollutants regulated 

under the NAAQS, including PM2.5, SO2, NOx, and precursors to 

ozone. In addition, several pollutants emitted from cement 

kilns are transformed in the atmosphere into PM2.5, including SO2, 

NOx, and VOC. Emissions of NOx and VOC are also precursors to 

ozone. Thus, implementation of the Cement NESHAP, which could 

lead to substantial reductions in criteria pollutants and 

precursor emissions as co-benefits, could help areas around the 

country attain the NAAQS. 

Screening analyses showed that 23 cement facilities were 

located in 24hr PM2.5 NAA and 39 facilities in Ozone NAA. 

Control strategies for reducing emissions of THC, mercury, HCl, 

and PM from cement plants under the Cement NESHAP have the cobenefits of reducing SO2 and direct PM2.5 emissions. These cobenefits could provide states with emission reductions for areas 

required to have attainment plans.

Regional Haze, Reasonable Progress, and the Cement Sector-based 

Strategy
109

The Cement NESHAP can also have an impact on regional haze. 

Under section 169A of the CAA, States must develop SIPs to 

address regional haze. The purpose of the regional haze program 

is the prevention of any future, and the remedying of any 

existing, impairment of visibility in mandatory Class I areas 

which impairment results from manmade air pollution Under the 

regional haze regulations, the first Regional Haze SIPs were due 

in December, 2007 (40 CFR 51.308(b)); these SIP submittals must 

address several key elements, including Best Available Retrofit 

Technology (BART), Reasonable Progress, and long-term 

strategies. Screening analyses showed that there are 14 cement 

facilities within a distance of 50 km Class 1 Areas.

A potential benefit for cement facilities utilizing wet 

scrubbers to comply with this rule is a level of certainty for 

satisfying a facility’s BART requirements for SO2 under the 

regional haze program. This rule may establish a framework for 

States to include certain control measures or other requirements 

in their regional haze SIPs where such a program would be 

“better than BART.” A facility must comply with BART as 

expeditiously as practicable but no later than 5 years after the 

regional haze SIP is approved. A state may be able to rely on 

this rule to satisfy the BART requirements for a NESHAP affected 

source utilizing a wet scrubber if (1) the compliance date for a 

source subject to this NESHAP falls within the BART compliance 
110

timeframe, (2) the proposed controls are more cost effective 

than the controls that would constitute BART, and (3) the 

visibility benefits of the controls are at least as effective as 

BART.

States may also allow sources to “average” emissions across 

any set of BART-eligible emissions units within a fence-line, 

provided the emissions reductions from each pollutant being 

controlled for BART are equal to those reductions that would be 

obtained by simply controlling each of the BART-eligible units 

that constitute the BART-eligible source (40 CFR 51.308(e)(2)). 

This averaging technique may also be advantageous to cement 

facilities subject to this NESHAP that also have BART-subject 

sources.

Under the regional haze rule, States may develop an 

alternative “better than BART” program in lieu of source-bysource BART. The alternative program must achieve greater 

reasonable progress than BART would toward the national 

visibility goal. The alternative program may allow more time 

for compliance than source-by-source BART would have allowed. 

Any reductions relied on for a better than BART analysis must be 

surplus as of the baseline year the State relies on for purposes 

of developing its regional haze SIP (i.e., 2002) and can include 
111

reductions from non-BART and BART sources.51 Visibility analyses 

must verify that the alternative program, on average, gets 

greater visibility improvement than BART and that no degradation 

in visibility on the best days occurs (40 CFR 51.308(e)(3)).

EPA believes that emissions units at cement sources found 

to be subject to BART and that will be required to install 

controls or otherwise achieve emissions reductions per the 

regional haze regulations can benefit from this Cement NESHAP to 

potentially satisfy the regional haze requirements. EPA will 

need to demonstrate that the implementation of the cement NESHAP 

will result in SO2 emissions reductions and related visibility 

improvements that are greater than reductions achieved through 

the application of BART controls. If EPA demonstrates that the 

SO2 emissions reductions and visibility and air quality 

improvements resulting from the rule are better than BART, this 

demonstration, when incorporated into the Regional Haze SIP, is

anticipated to fulfill federal regulatory requirements 

associated with BART requirements for cement facilities. 

Additionally, the level of control achieved through the 

Cement NESHAP may contribute toward, and possibly achieve, the 

visibility improvements needed to satisfy the reasonable 

 

51November 18, 2002 memo from EPA’s Office of Air Quality 

Planning and Standards entitled “2002 Base Year Emission 

Inventory SIP Planning: 8-hr Ozone, PM2.5, and Regional Haze 

Programs." 
112

progress requirements of the regional haze rule for cement 

facilities through the first Regional Haze planning period. 

States can submit the relevant regional haze SIP amendments once 

this rule becomes final. 

Health Benefits of Reducing Emissions from Portland Cement Kilns

Implementation of the Cement NESHAP, which could lead to 

substantial reductions in PM2.5, SO2, and toxic air pollutants, 

could reduce numerous health effects. 

Section VI.J of this preamble provides a summary of the 

monetized human health benefits of this proposed regulation 

based on the Regulatory Impact Analysis available in this docket 

that includes more detail regarding the costs and benefits of 

this proposed regulation. 

As mentioned before, portland cement kilns emit several

pollutants with known human health effects, including PM2.5, SO2, 

NOx, and precursors to ozone. Exposure to PM2.5 is associated with 

significant respiratory and cardiac health effects, such as 

premature mortality, chronic bronchitis, nonfatal heart attacks, 

hospital admissions, emergency department visits, asthma 

attacks, and work loss days. USEPA, Air Quality Criteria for 

Particulate matter, chapter 9.2 (October 2004). Exposure to SO2

and NOx is associated with increased respiratory effects, 

including asthma attacks, hospital admissions, and emergency 

department visits. Exposure to ozone is associated with 
113

significant respiratory health effects, such as premature 

mortality, hospital admissions, emergency department visits, 

acute respiratory symptoms, school loss days. 

In addition, portland cement kilns emit toxic air 

pollutants, including mercury and HCl. Exposure to high levels 

of mercury is associated with central nervous system damage, 

kidney damage, blindness, deafness, speech difficulties, and 

developmental effects. Acute inhalation exposure to 

hydrochloric acid is associated with irritation of mucous 

membranes, inflammation, and fluid accumulation in the lungs. 

We welcome comments and suggestions related the 

interactions of this proposed NESHAP and other regulatory 

requirements in the context of the sector-based considerations 

described above.

I. Other Changes and Areas Where We are Requesting Comment

Startup, Shutdown and Malfunction. The Court of Appeals for the 

District of Columbia Circuit recently vacated EPA’s rules 

exempting major sources from otherwise applicable emission 

standards during periods of startup, shutdown and malfunction. 

Sierra Club v. EPA, F.3d (2008). A consequence is that EPA must 

develop section 112(d) standards for these operating conditions 

for previously-exempted major sources. Portland cement kilns

are among these previously-exempted source categories. For 

purposes of this proposed rule, this means that that these 
114

sources must now either meet generally applicable emission 

standards at all times, or EPA must develop section 112 (d) 

standards for cement kilns when operating under startup, 

shutdown or malfunction conditions. 

EPA is not now at a point where it can propose quantitative 

standards for cement kilns operating in startup, shutdown and 

malfunction modes. Accordingly, the Agency solicits comment, 

including available data, addressing this issue. In addition, 

there is likely to be a difference in standards depending on 

which of the modes is at issue. Startup and shutdown are both 

somewhat controlled operating modes for cement kilns (although 

occurring over different time periods), though we believe that 

shutdowns can vary (planned or emergency) and startups can be

from a cold or a hot kiln. Malfunction conditions are (by 

definition) unanticipated occurrences for which control 

strategies are mainly reactive. EPA thus requests that 

commenters differentiate among the five operating modes in 

addressing this issue. EPA notes further that it may notice 

data received on this issue for further public comment as part 

of this rulemaking.

Data used to set existing source floors. The emissions 

standards included in the proposed rule were calculated using 

the emissions information available to the Administrator, in 

accordance with EPA’s interpretation of the requirements of 
115

section 112(d)(3) of the Act. In developing this proposed rule, 

we specifically sought data from as many kilns as possible given 

the time constraints when we began our data collection process. 

Given that there are 152 kilns in this source category, the 12 

percent representing the best performing kilns would be 19 

kilns. However, in some cases we have emission data from as few 

as 12 cement kilns, which means that existing source floors were 

proposed using as few as 2 kilns (although we are soliciting 

comment on an alternative interpretation that would allow EPA to 

base floors on a minimum of five sources’ performance in all 

instances where those data exist. EPA knows that more emissions 

information from other kilns, both with and without similar 

process and control characteristics, would lead to a better 

characterization of emissions from the entire population of 

cement kilns, as well as a better description of intra-source, 

inter-source, and test method variability, and that statistical 

techniques can be employed to provide the expected distribution 

of emissions for the cement kiln population. EPA thus requests 

commenters to provide additional emissions information on cement 

kilns’ performance. 

HCl Test Data and Methods. In some instances, the 

emissions standards included in the proposed rule were 

calculated using emissions information provided to EPA that 

appears to be below detection levels established more than 15
116

years ago. More specifically, Method 321 identifies a practical 

lower quantification range for hydrogen chloride from 1000 to 

5000 parts per billion for a specific path length and test 

conditions. Many of the best performing sources with respect to 

HCl emissions report both values and detection levels below 1000 

parts per billion. While it is not surprising that detection 

levels should decrease as improvements in analytical methods 

occur over time, EPA does not have the emissions information and 

other data necessary to assess independently the new, lower 

detection levels, some as low as 20 parts per billion. 

Without additional data or detection limit calculations, 

EPA could maintain the old detection limit, accept the sourceprovided limit, or modify the source-provided limit to an 

expected new acceptable level. Selection of an appropriate 

detection limit is no trivial matter, as the detection limit 

could impact how the available data would be used in average 

emissions calculations. EPA could choose not to use any data 

below the detection limit in calculations. EPA could also 

choose to set all data below the detection limit at a value 

corresponding to one-half the detection limit for average 

calculation purposes, reasoning that any amount of emissions 

between zero and the detection limit could occur when the 

detection limit is recorded. Indeed, this approach, setting all 

data below the detection limit at a value corresponding to one-
117

half the detection limit, was chosen by the sources that 

provided emissions information to EPA. EPA could also set all 

data below the detection limit at a value corresponding to the 

detection limit, or to zero, for average calculation purposes. 

Finally, EPA could apply statistical techniques to available 

emissions information both above and below the detection limit 

to provide the expected distribution of HCl emissions for the 

cement kiln population. A further issue, with any of these 

possible approaches, would be to assess sources’ operating 

variability.

EPA based the HCl emissions limitations contained in the 

proposal using the source-provided detection limits and setting 

all data below the detection limit at a value corresponding to

one-half the detection limit for average calculation purposes. 

This approach is consistent with the emissions information 

supplied by sources to EPA. See also Rybachek v. EPA, 904 F. 2d 

1276, 1296 (9th Cir. 1990)(upholding use of this approach in 

setting technology-based Clean Water Act effluent limitation 

guideline standards). Should EPA receive additional emissions 

information sufficient to calculate detection limits from 

already-received data or emissions information including 

detection limit calculations from other sources, EPA would be 

able to ascertain and revise, if necessary, the new detection 

limits and to calculate a different HCl standard.
118

EPA requests additional HCl emissions information, 

including such information as needed to calculate detection 

limits, as well as detection limit calculations. Moreover, EPA 

requests comments on which way, if any, to set the emission 

detection limit and to handle emissions information below the 

detection limit are suitable for use in this proceeding. For 

those commenters who believe EPA’s proposed emission detection 

limit and process to handle values below the detection limit may 

not be suitable, EPA requests commenters to provide their views 

of acceptable detection limits and processes that use values

below the detection limits to calculate averages, as well as 

examples of sample calculations using those processes. We are 

also requesting comment on the same issues relating to the use 

of a CEMS meeting the requirements of PS-15 to measure HCl 

emissions.

Submission of Emissions Test Results to EPA. Compliance 

test data are necessary for many purposes including compliance 

determinations, development of emission factors, and determining 

annual emission rates. EPA has found it burdensome and time 

consuming to collect emission test data because of varied 

locations for data storage and varied data storage methods.

One improvement that has occurred in recent years is the 

availability of stack test reports in electronic format as a 

replacement for burdensome paper copies.
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In this action, we are taking a step to improve data 

accessibility for stack tests (and in the future continuous 

monitoring data). Portland cement sources will have the option 

of submitting to WebFIRE (an EPA electronic data base), an 

electronic copy of annual stack test as well as process data. 

Data entry requires only access to the Internet and is expected 

to be completed by the stack testing company as part of the work 

that they are contracted to perform. This option would become 

available as of December 31, 2011.

Please note that the proposed option to submit source test 

data electronically to EPA would not require any additional 

performance testing. In addition, when a facility elects to 

submit performance test data to WebFIRE, there would be no 

additional requirements for data compilation; instead, we 

believe industry would greatly benefit from improved emissions 

factors, fewer information requests, and better regulation 

development as discussed below. Because the information that 

would be reported is already required in the existing test 

methods and is necessary to evaluate the conformance to the test 

method, facilities would already be collecting and compiling 

these data. One major advantage of electing to submit source 

test data through the Electronic Reporting Tool (ERT), which was 

developed with input from stack testing companies (who already 

collect and compile performance test data electronically), is 
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that it would provide a standardized method to compile and store 

all the documentation required by this proposed rule. Another 

important benefit of submitting these data to EPA at the time 

the source test is conducted is that it will substantially 

reduce the effort involved in data collection activities in the 

future. Specifically, because EPA would already have adequate 

source category data to conduct residual risk assessments or 

technology reviews, there would be fewer data collection 

requests (e.g., section 114 letters). This results in a reduced 

burden on both affected facilities (in terms of reduced manpower 

to respond to data collection requests) and EPA (in terms of 

preparing and distributing data collection requests). Finally, 

another benefit of electing to submit these data to WebFIRE 

electronically is that these data will greatly improve the 

overall quality of the existing and new emissions factors by 

supplementing the pool of emissions test data upon which the 

emission factor is based and by ensuring that data are more 

representative of current industry operational procedures. A 

common complaint we hear from industry and regulators is that 

emissions factors are out-dated or not representative of a 

particular source category. Receiving most performance test

results would ensure that emissions factors are updated and more 

accurate. In summary, receiving these test data already 

collected for other purposes and using them in the emissions 
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factors development program will save industry, 

State/local/tribal agencies, and EPA time and money.

As mentioned earlier, the electronic data base that will be 

used is EPA’s WebFIRE, which is a Web site accessible through 

EPA’s TTN. The WebFIRE Web site was constructed to store 

emissions test data for use in developing emission factors. A 

description of the WebFIRE data base can be found at 

http://cfpub.epa.gov/ oarweb/index.cfm?action=fire.main. The 

ERT will be able to transmit the electronic report through EPA’s 

Central Data Exchange (CDX) network for storage in the WebFIRE 

data base. Although ERT is not the only electronic interface 

that can be used to submit source test data to the CDX for entry 

into WebFIRE, it makes submittal of data very straightforward 

and easy. A description of the ERT can be found at 

http://www.epa.gov/ttn/chief/ert/ ert_tool.html. The ERT can be 

used to document the conduct of stack tests data for various 

pollutants including PM (EPA Method 5 of appendix A–3), Mercury

(EPA Method 29 of appendix A–8), and HCl (EPA Method 321 of 

appendix A–8). Presently, the ERT does not handle dioxin/furan 

stack test data (EPA Method 23 of appendix A–7), but the tool is 

being upgraded to handle dioxin/furan stack test data. The ERT 

does not currently accept opacity data or CEMS data.

EPA specifically requests comment on the utility of this 

electronic reporting option and the burden that owners and 
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operators of portland cement facilities estimate would be 

associated with this option.

Definition of affected source. In the final amendments 

published on December 20, 2006, we indicated that we were 

changing paragraph (c) in §63.1340 to clarify that crushers were 

part of the affected source for this rule (71 FR 76532). 

However, we omitted the rule language changes to that paragraph. 

This language has been added to this proposed rule.

V. Summary of Comments and Responses on Notice of 

Reconsideration and EPA Final Action in Response to Remand

This section presents a summary of comments received on the 

final action published on December 20, 2006. We are not 

responding to these comments in this proposed action. We will 

provide responses to these comments, and other comments received 

on these proposed amendments, when we take final action on this 

proposal. 

A. Petition to Withdraw Final Standards

Commment: One commenter petitioned EPA to withdraw the new 

source standards for mercury and THC, as well as the provision 

in §63.1344(i) concerning the allowable CKD recycle rate because 

of procedural defects and the lack of record support. Several 

commenters agree that EPA should withdraw the standards for the 

same reasons given in the petition.
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The commenter stated that the proposed rule was silent on 

the possibility of issuing a new source standard for mercury 

based on a wet scrubber, a new source standard for THC based on 

an RTO, and the operating limit for new and reconstructed kilns 

in §63.1344(i). EPA violated CAA section 307(d)(3) and (d)(5) 

by not proposing these requirements and not providing an 

opportunity for comment. The commenter also alleged that 

comments filed by the public did not lead EPA to the positions 

taken in the final rule. Therefore, EPA cannot argue that the 

final standards represent a “logical outgrowth” of the proposal. 

EPA application of the reconsideration process does not 

cure these defects. EPA lacks authority to initiate 

reconsideration on its own through CAA section 307(d)(7)(B); 

this provision clearly is designed for a process in response to 

request by another person. There appears to be no precedent for 

this action and EPA did not cite any precedent. 

The commenter also argued that the standards lack record 

support and are therefore arbitrary and capricious under CAA 

section 307(d)(9)(A). EPA conceded in the final rule and notice 

of reconsideration that it was unclear whether the new source 

standards for mercury and THC are “achievable” or appropriate 

(see pages 12-14). For the provision concerning the CKD recycle 

rate, EPA provided no explanation as to whether it was possible 

to continually “not exceed the average hourly CKD recycle rate 
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during mercury performance testing” or whether any cement kiln 

has achieved this result in practice. Because EPA did not point 

to any “best controlled” existing source that has achieved such 

a recycle rate, the provision violates the MACT floor 

requirements for new sources in CAA section 112(d)(3). EPA in 

effect promulgated a beyond the floor standard without 

considering the required criteria (including costs) in CAA 

section 112(d)(2). EPA also did not demonstrate that the 

requirement is achievable, did not provide a “statement of basis 

and purpose” for the requirement, or an explanation of the 

reasons for changes from the proposal in this regard, as 

required by CAA section 307(d)(6)(A).

 According to the commenter, EPA’s promulgation of these 

standards, coupled with the notice for reconsideration, has 

created significant uncertainty and will require construction 

delays until the issues are resolved or installation of the 

technologies regardless of whether they are necessary; either 

will result in financial harm to several companies. 

B. Petition to Reconsider Final Standards 

One commenter petitioned EPA to reconsider the work 

practice standards for mercury and THC, the decision not to set 

standards for HCl, and the decisions not to set beyond-the-floor 

standards for mercury and THC.
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Comment: The commenter argued that the work practice 

standards for mercury and THC are unlawful. The D.C. Circuit 

Court remanded the cement kiln rule with instructions to set 

MACT floor standards for HCl, mercury, and THC. However, EPA 

set work practice standards instead of emission standards. The 

commenter asserted that the work practice standards are not and 

do not purport to be emission standards. The CAA makes it 

entirely clear that for the purpose of section 112, a work 

practice standard is not an emission standard. Section 112(h) 

provides that “if it is not feasible ... to prescribe or enforce 

an emission standard for the control of a hazardous air 

pollutant or pollutants, the agency may in lieu thereof, 

promulgate a design, equipment, work practice, or operational 

standard . . .” The clarity of section 112 on this point is not 

diminished by section 302(k)’s definition of “emission standard” 

to include a work practice standard. Section 112(h) is the more 

specific provision with respect to section 112 standards. 

Reading “emission standard” to include work practice standards 

would nullify the distinction that section 112(h) draws between 

the two, and essentially render section 112(h) meaningless and 

surplus. Because the only requirements EPA established for 

emissions of mercury and THC from existing kilns are work 

practice standards rather than emission standards, the final 

rule violates National Lime’s mandate to set emission standards. 
126

The commenter also argues that the work practice standards, if 

they could be viewed as emission standards, do not satisfy the 

MACT floor requirements in section 112(d)(3); EPA did not 

purport the work practices reflect the relevant best sources’ 

emission levels or the best performing 12 percent of kilns, 

which EPA has never identified. The commenter also stated that 

the work practices do not satisfy section 112(h) because EPA did 

not claim that was not feasible to prescribe or enforce an 

emission standard for either pollutant. EPA could not make this 

claim because both pollutants are emitted from kiln stacks and 

it is technologically or economically impractical to measure the 

emissions.

Comment: The commenter alleges that EPA’s refusal to set 

any emission standards for HCl is unlawful. The commenter 

claimed that section 112(d)(4), which EPA cited as its authority 

for declining to set emission standards for HCl, does not excuse 

EPA from setting standards for a pollutant but merely provides 

that it is there as an established health threshold for a 

pollutant, EPA may consider that threshold, with an ample margin 

of safety when establishing emission standards. According to 

the commenter, EPA confirmed that it did not know whether or not 

HCl causes cancer. Because EPA does not know whether HCl is 

carcinogenic, EPA has not identified a health threshold below 

which HCl does not cause cancer. Therefore, EPA can not invoke 
127

section 112(d)(4) with respect to HCl. The commenter also 

stated that EPA’s attempts to rely on its statements about HCl 

in previous rules are unfounded. The 1998 rule on which EPA 

primarily relies classified HCl as a Group D pollutant (one for 

which EPA lacks data about carcinogenicity). Classification of 

a pollutant in Group D merely underscores that EPA cannot 

support a finding that a pollutant is a threshold pollutant with 

respect to cancer. In addition, the 1998 rule made the Group D 

classification only for the purposes of that rule and not for 

any other actions.

The commenter also pointed out that EPA has not identified 

a threshold for non-cancer effects. The threshold EPA claimed 

to have identified as the reference dose concentration (RfC), 

i.e., the long term threshold, must be a level below which no 

adverse health effects occur. The level that EPA claims is a 

threshold does not meet this requirement because it was based on 

a single animal study which used only one dose, looked only at 

respiratory effects, not effects on other bodily systems, and 

identified only a lowest observed adverse effects level at which 

adverse effects did occur, not a threshold at which adverse 

effects do not occur. The commenter stated that EPA effectively 

acknowledged that exposure to HCl does damage people’s heath (71 

FR 76542). Congress intended EPA to apply section 112(d)(4) 
128

where there is no risk of adverse health effects. Tissue damage 

is an adverse health effect.

The commenter stated that EPA’s reliance on a risk 

assessment prepared by an industry trade association is unlawful 

and arbitrary. The record does not show any attempt to verify 

the data, methodology, or results and the analysis gives no 

indication when the data was obtained, whether it reflects 

ongoing conditions, whether it accounts for potential emissions 

and modifications, whether the assumptions and emissions levels 

in the analysis are representative, or why one-third of the 

plants are not included. The commenter also argued that 

analysis did not adequately show that HCl emissions from the 

kilns covered by study are below the RfC. According to the 

commenter, the analysis uses default rather than kiln-specific 

data for all but one variable to estimate HCl emissions and 

concentrations. Even if the study showed conclusively that HCl 

levels were at or below the RfC, the absence of data and 

mischaracterization of background levels prevents EPA from 

showing that it has provided an ample margin of safety as 

required by CAA section 112(d)(4). According to the commenter, 

the analysis mischaracterized background emissions and provides 

no reason to believe that HCl background levels in areas where 

kilns operate is not higher or that background levels have not 

increased compared to 1996 and 1999 values, does not account for 
129

variability, and does not adequately account for co-location of 

industrial facilities. The analysis of background levels for 

short-term hazard quotient is similarly flawed. The commenter 

also criticized the application of a rural parameter to all 

kilns, which is not the case for many kilns.

Section 112(d)(4) also requires that the standards do not 

have any adverse environmental effects. No ecological 

assessment was conducted for the analysis or by EPA. In fact, 

the analysis does not even claim there would be no impacts, only 

that any deleterious effects were likely to be localized rather 

than widespread. 

Comment: The commenter criticized EPA’s beyond-the-floor 

determination for mercury emissions. According to the 

commenter, EPA conducted beyond-the-floor analyses for all 

“demonstrated” control techniques excluding all of the 

techniques raised in public comments except for ACI and wet 

scrubbers. EPA’s claim that it can ignore technologies if the 

Agency does not believe that they are “demonstrated control 

techniques for the cement industry” is unlawful. Section 

112(d)(2) requires beyond-the-floor standards to reflect the 

maximum degree of reduction that is achievable through the full 

range of potential reduction measures. There is no precondition 

that control technologies must be demonstrated in the industry 

to be regulated.
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EPA’s rejection of ACI as not cost-effective based on new 

cost estimates is unlawful and arbitrary for all the reasons 

given in comments on the proposed rule. EPA’s rejection of ACI 

is also unlawful and arbitrary because: (1) EPA alludes to 

increased energy use but does not say what increase would occur 

and why that justifies rejection of ACI; and (2) EPA alludes to 

increased solid waste generation, but does not say why the 

specific amount generated weighs against beyond-the-floor 

standards or why it is preferable for mercury to be emitted to 

the air rather than contained in solid waste. The Agency must 

explain the relevance of a specific statutory factor to beyond 

the floor analysis and how consideration of that factor supports 

its conclusion.

Although EPA acknowledged that ACI reduces THC, the cost 

effectiveness analysis remains arbitrary because EPA never 

determined the cost effectiveness of ACI with respect to all the 

HAP it controls (including polychlorinated biphenyls, polycyclic 

organic matter, and benzene). Further, the analysis mistakenly 

assumes that the same ACI device would have to be purchased 

separately with respect to each HAP, when the device is a single 

investment that would reduce many pollutants. In addition, EPA 

did not explain why it considers the amount of THC that would be 

reduced as “small” (30 to 117 tpy per kiln is significant) or 

why such a reduction is not justified. Finally, EPA’s claim 
131

that it can reject a beyond-the-floor measure, not because the 

measure is not “achievable”, but because it does not view the 

cost as “justified” is unlawful for the reasons given in 

previous comments.

Comment: EPA’s rejection of a beyond-the-floor standard 

banning the use of utility boiler fly ash where such use 

increases mercury emissions is unlawful and arbitrary. EPA 

claims that this measure is not “justified” because of cost, 

energy, and non-air environmental impacts. The CAA requires EPA 

to set final standards reflecting the maximum degree of 

reduction that is “achievable” considering costs and other 

factors, not the degree of reduction that EPA thinks is 

“justified” in light of those factors. And, because EPA 

admitted that it did not know what the costs of this measure 

would be, reliance on cost arguments to reject the provision is 

arbitrary. Also arbitrary is EPA’s reliance on non-air impacts 

(the increased amount of utility boiler ash that would have to 

be otherwise disposed of). EPA did not explain why: (1) the 

need for utility boilers to dispose of their ash would be a 

worse problem than the release to the air of the mercury 

contained in the ash; (2) all the ash that is currently used in 

kilns would require disposal when it can be used in concrete 

without going to the kiln; (3) kilns that are currently using 

fly ash would have to use raw materials if the use of fly ash 
132

that increases mercury emissions were banned; (4) the 

undetermined amount of mining necessary for an undetermined 

number of kilns that had to stop using any fly ash would be a 

worse problem than the mercury emissions that result from the 

use of the fly ash such that the concern about additional mining 

weighs against the beyond the floor measure. EPA also cites 

energy concerns as a reason for rejecting the beyond the floor 

measure but does not identify or explain them.

Comment: The commenter criticized EPA’s beyond-the-floor 

determination for THC emissions. EPA rejected beyond-the-floor 

standards based on ACI and wet scrubbers combined with RTO

(scrubber/RTO) based on the costs per ton of THC removed and 

organic HAP removed and alleged concerns about increased energy 

use and adverse non-air quality health and environmental 

impacts. EPA also rejected optimized combustion practices 

because it lacks the data to evaluate reductions and the use of 

a carbon coke system because the Agency considered scrubber/RTO 

and therefore does not have to consider other options that are 

not already in use in this country. EPA’s claim that it can 

reject a beyond-the-floor measure not because it has determined 

that the measure is not “achievable” but because the cost is not 

justified is unlawful for the reasons given in comments on the 

proposed rule. Further, EPA’s contention that beyond-the-floor 

standards based on ACI and scrubber/RTO would not be justified 
133

on cost grounds is not explained. The cost of reducing THC as a 

surrogate for all the non-dioxin organic HAP from the kilns is 

reasonable and well within the ranges EPA has found acceptable 

for other rules. EPA can not look past the cost of the THC 

reduction as the reason for rejecting the measure. If THC is 

not a valid surrogate, EPA should find a different surrogate or 

establish separate limits for each pollutant. It is arbitrary 

to choose a surrogate for some purposes but not others. In 

addition, EPA cost effectiveness estimates for organic HAP are 

unexplained, unsupported by the record, and arbitrary. EPA did 

not explain its assumption that organic HAP comprise 5 percent 

of the THC, which organic HAP it is counting, or the quantity of 

emissions from these HAP. In addition, determining the cost 

effectiveness of all non-dioxin organic HAP on a single cost per 

ton basis is not warranted because these HAP emissions vary in 

quantity and toxicity. EPA also does not provide any basis for 

its arguments about energy use and solid waste or why these 

impacts make the beyond the floor measure either unachievable 

(the statutory standard) or unjustified (EPA’s preferred 

standard).

EPA’s rejection of optimized combustion controls is 

arbitrary and unlawful. According to the commenter, EPA argues 

that it does not even have to consider potential reduction 

measures if it does not already have data for them. EPA cannot 
134

frustrate section 112(d)(2) requirements by declining to collect 

information. Congress required the maximum degree of reduction 

that is achievable through all potential reduction measures, not 

the maximum degree of reduction achievable through measures for 

which the Agency deigns to collection information.

EPA’s rejection of carbon coke technology is arbitrary 

because the Agency provided no rationale basis for its 

conclusion. EPA rejected carbon coke technology because it is 

used by a kiln in another country. No language in the CAA 

suggests that EPA may refuse to consider a technology because it 

is not already in use in this country or because the Agency has 

considered some other technology.

C. New Source MACT for Mercury Emissions and Related 

Requirements

Comment: One commenter states that new cement kilns are 

not likely to install wet scrubbers in areas where the raw 

materials are low in sulfides. The commenter recommends that 

EPA include an alternative standard for new kilns that allows 

the owner or operator to average mercury emissions over all 

modes of the raw mill operation on a monthly basis to achieve 

the same limit in the final rule.

Comment: One commenter explained that a 3 to 9 hour stack 

test on a cement kiln cannot provide an accurate or 

representative estimate of long-term mercury emissions. The 
135

rate of mercury emissions from a modern precalciner kiln is 

constantly changing. Even a 1 week test can not provide a 

representative picture of long-term (1 year) mercury emissions 

from these systems.

Comment: One commenter asks that EPA require more 

representative mercury monitoring such as the periodic use of 

EPA Method 324 (Sorbent Trap) or mercury CEMS at all cement 

kilns based on their mercury emission profiles and raw material 

practices.

Comment: One commenter points to high mercury emissions in 

2004 with reduced emissions in 2005 from one cement plant in 

California and one cement plant in Oregon based on the most 

recent toxic release inventory submittals. The commenter asks 

EPA how mercury was reduced at these sites in 2005 and how they 

will be reduced at these sites in the future and for EPA to 

determine whether the concepts used by the plants can be used in 

more kilns.

Comment: One commenter pointed out that mercury emissions 

from cement plants are higher than the entire mercury budgets 

for future coal-fired power plants emissions in numerous States. 

The revisions made after reconsideration must be at least as 

stringent as the December 2006 final rule. Another commenter 

states that EPA has not effectively controlled mercury emissions 
136

from cement kilns; new and existing kilns should have the most 

stringent requirements.

D. New Source MACT for THC Emissions and Related Requirements

Comment: One commenter objected to the MACT floor for new 

kilns based on the single application of a wet scrubber and RTO. 

According to the commenter, EPA stated that two facilities have 

attempted to use the technology; at one facility the systems did 

not operate continuously due to significant operational problems 

caused by the site specific constituents in the flue gas but the 

technology operates continuously and effectively at the second 

facility. The commenter claimed that the standard is based on a

technology that has not been demonstrated to work in all 

applications. In addition, the technology at the second 

facility has not worked continuously and effectively as EPA 

claimed. According to the commenter, the technology has 

experienced operational and maintenance problems at both 

facilities. The commenter stated that EPA’s evaluation of the 

MACT floor is flawed and should be reevaluated.

Comment: Some commenters disagreed with EPA’s cost 

estimates for wet scrubber/RTO technology. One commenter stated 

that the capital costs at the two facilities referenced by EPA 

for a 1 million tpy kiln are $18 to $25 million for wet 

scrubbers and $15 to $20 million for RTO compared to EPA’s 

estimate of $10.7 million.
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One commenter stated that requiring the wet scrubber/RTO 

technologies for new sources may make new construction 

economically infeasible and that neither the wet scrubbing nor 

RTO technologies have been required based on permitting/new 

source review requirements. Another commenter stated that the 

new source MACT requirements for THC (wet scrubber/RTO) will 

have a negative impact on the local watershed which can not 

afford the additional 58.5 million gallons of water per year for 

a wet scrubber. 

Comment: One commenter alleges that EPA’s statement on 

consultation with Indian Tribes (no tribes were consulted about 

the rule because it would have no impact on them) is inaccurate 

because the commenter is constructing a new source on the Moapa 

Pauite Indian Reservation.

E. Cement Kiln Dust Requirements

Comment: One commenter said the CKD provision in 

§63.1344(h) is unworkable because it codifies as “static” a 

practice that varies from plant to plant. The primary purpose 

of removing CKD from the kiln system is to manage the 

concentration of alkali compounds in the clinker and subsequent 

cement. The amount of CKD removed varies according to the 

chemistry of the raw material feed. In addition, alkali 

specifications have changed as a result of State requirements, 

resulting in changes in the amount of CKD removed. And, plants 
138

that use a preheater/precalciner design do not remove CKD from 

the kiln system (and the material is not considered to be 

generated at these plants) while other plants using long dry or 

long wet technology remove CKD from the system but return it as 

a component of the raw material mix. Another commenter 

explained that removing CKD from the kiln system recycling loop 

is critical to the efficient control of mercury emissions.

Another commenter stated that the CKD provision, as 

written, could be interpreted to require removal of CKD from the 

system. Unnecessary removal would create a new solid waste 

problem and reduced the energy efficiency of the process if the 

amount of raw materials going into the process had to increase 

as a result of the CKD being removed.

Finally one commenter requests that EPA clarify the CKD 

provision for existing sources in §63.1344(h). EPA explained in 

the preamble that a facility must remove CKD from the system “at 

the point product quality is adversely affected.” The comment 

asks whether “the point” is a point in time, point in the cement 

manufacturing process, or point on the continuum of cement 

product chemistry. Also, what “product quality” standard is 

meant (i.e., ASTM, American Association of State Highway 

Transportation Officials, ANSI, or another standards 

organization)? Is there a need for different compliance 
139

approaches to suit the various types of cement (e.g., Type 1, 

Type V) produced by an individual facility?

F. Fly Ash Requirements

Comment: Some commenters urged EPA to stand by its 

decision not to ban all fly ash but object to the fly ash 

provision as promulgated. According to the commenters, the ban 

could result in increased landfilling of the ash. The 

prohibition was adopted without proper notice and comment and 

EPA adopted the ban based on consultations with one industry 

sector without discussing it with the sector most affected (coal 

burning power industry). The commenters also disagreed with 

EPA’s explanation that the fly ash prohibition could be imposed 

without any immediate impacts because utilities will not be 

installing ACI or other forms of sorbent injection until at 

least 2010. The commenters believed that adverse effects are 

likely as early as 2007 when plants begin testing or plants must 

comply with State regulations.

The commenters stated the prohibition was inflexible 

because it does not allow for exceptions regardless of the 

emission control technologies used at the kiln. If there is 

justification for a ban on the use of mercury-enhanced fly ash 

in kilns with no controls, EPA failed to address the need for a 

ban at kilns with controls (i.e., wet scrubbers, ACI, fabric 

filters). The provision allowing the kiln to demonstrate that 
140

the fly ash will not increase mercury emissions over baseline 

levels puts the burden and cost of testing the emissions on the 

cement plant. The cement plant could easily avoid the burden by 

using alternative feedstock, possibly with higher mercury 

concentrations. It is unrealistic to expect the cement industry 

to spend resources on the testing especially if the kiln already 

has emission controls and no testing requirements apply to any 

other feedstock. EPA should amend §63.1344(g) to exclude plants 

already subject to a mercury standard as follows:

No kiln and in-line kiln/raw mill may use as a raw 

material or fuel any fly ash where the mercury content 

of the fly ash has been increased through the use of 

activated carbon, or any other sorbent if it will 

result in an increase of mercury input to the process 

unless the facility desiring to use the fly ash is 

already subject to a mercury standard (either an 

emission or input limitation) or unless the facility 

can demonstrate that the use of that fly ash will not 

result in an increase in mercury emissions over 

baseline emissions (i.e., emissions not using the fly 

ash). The facility has the burden of providing there 

has been no emissions increase over baseline.

This change would allow kilns that have installed emission 

controls to rely on them without additional testing, 

demonstrations, or certifications and would not penalize one 

feedstock from one industry sectors while favoring other 

feedstocks that may contain higher mercury concentrations.

Comment: One commenter pointed out that the final rule 

includes a ban only on fly ash derived from power plants that 

use ACI to reduce mercury emissions. The commenter recommends 
141

that EPA expand the scope of the limited fly ash ban to address 

high loss on ignition (LOI) or selective catalytic reduction 

(SCR)-affected fly ash laden with mercury. Such fly ash should 

be treated in a like manner to ash containing activated carbon. 

Expanded mercury measurement and removal strategies should be 

incorporated if use of such fly ash is allowed at cement plants. 

The commenter provides information explaining how fly ash can 

become enriched with mercury due to combustion controls for

nitrogen oxide (NOX) (i.e., low NOX burners, separate overfire 

air, reburn) and SCR. High emissions of mercury may result from 

power plant fly ash where ACI is not used to control mercury 

emissions.

Another commenter stated that cement kilns combusting fly 

ash containing higher LOI fly ash after the ash has been 

beneficiated generally by electrostatic separation can emit 

higher levels of mercury. Cement kilns are currently burning 

beneficiated high LOI fly ash. Re-use of higher LOI 

beneficiated fly ash through combustion in cement kilns should 

be further evaluated.

Comment: One commenter objected to EPA’s assumption that 

the TOXECON system (which collects fly ash before sorbents are 

injected) will work for all power plants and be economically 

feasible; this technology has not be tested on medium and high 

sulfur bituminous coal and may not be effective. The commenter 
142

disagreed with EPA’s statement in the preamble that “technology 

is being developed that would allow the mineral-rich portion of 

the fly ash to be separated from the high carbon/high mercury 

portion.” According to the commenter, the record does not 

identify these technologies by name or documents the cost. The 

commenter is aware of fly ash beneficiation technologies that 

remove carbon from fly ash so it can be used in concrete, but it 

is unclear whether these technologies can remove activated 

carbon containing adsorbed mercury.

Comment: Two commenters stated that the certification 

requirements for fly ash contaminated by activated carbon are 

too burdensome. The commenters objected to the requirement in 

§63.1344(o) for facilities to obtain from the fly ash supplier a 

certification for each shipment of fly ash. The amount of fly 

ash used varies considerably, but some plants receive numerous 

shipments on a daily basis. The commenters recommend that the 

rule require each supplier to provide an initial certification 

confirming that the fly ash does not contain activated carbon 

used to capture mercury. A new certification could be required 

annually or if the treatment method was changed. 

G. Compliance Dates for Cement Kiln Dust and Fly Ash Provisions

Comment: Several commenters asked EPA to clarify the 

compliance dates for the CKD recycle rate provision for existing 

sources in §63.1344(h), the CKD recycle rate provision for new 
143

and reconstructed sources in §63.1344(i), and the provision on 

fly ash use in §63.1344(g). The commenters recommend that EPA 

allow 1 year to comply with the fly ash provision for existing 

sources in §63.1344(g) and CKD recycle rate provision for 

existing sources in §63.1344(h). That would make the compliance 

dates for these requirements consistent with the compliance date 

for existing sources to meet the THC good combustion practices 

(December 20, 2007) in §63.1351(c).

One commenter asks that EPA revise the compliance date for 

the CKD recycle rate provision for new and reconstructed kilns 

in §63.1344(i). Since EPA never proposed the provision, the 

final rule is more stringent than the proposal and sources 

commencing construction between December 2, 2005, and December 

20, 2006, should be given 3 years to comply.

H. Research and Technology

Comment: One commenter requests EPA to conduct further 

research on the concept of bypassing mercury-enriched dust from 

PM control devices or raw meal to clinker product. ASTM and 

ASSHTO now allow intergrinding of 5 percent limestone with 

clinker to make Type I cement product. Type II cement can have 

any greater amounts of other constituents. There is the 

possibility that some dust or meal can be used to substitute 

milled clinker without harming the quality of the product. Some 
144

plants may be able to use this approach to bleed mercury from 

the process.

Comment: One commenter, an ash management company, is 

investing in beneficiation technology with the goal of 

utilization of the fly ash as is done now in Europe. This 

commenter asked EPA to assemble a technical record on the 

effects and uses of sorbents (and other approaches) to 

facilitate increased utilization.

Comment: One commenter identified SCR as an add-on control 

that can reduce THC and dioxins/furans (D/F) and convert mercury 

in the cement process into more collectible forms for subsequent 

bypass strategies. Two other commercially available strategies 

rely on catalysts to reduce NOX, THC, or D/F. One proven 

technology reacts ammonia with NOX in the presence of a catalyst 

with concurrent D/F and THC destruction. The second uses 

catalytic material fibers that are woven and layered with 

standard baghouse fabric such that both the catalytic 

destruction of D/F and particulate control are achieved. The 

fabric filter technology is described at 

www.environment.power.alstom.com/home/ by following the links to 

Industry Solutions/Products/Fabric Filters/Remedia Filter Bags. 

EPA should review the role of SCR at some kilns as a THC and D/F 

control strategy in its reconsideration of the final rule. SCR 
145

and catalytic fabric filters should be considered in EPA’s 

multi-pollutant evaluation of the cement industry.

VI. Summary of Cost, Environmental, Energy, and Economic 

Impacts of Proposed Amendments

A. What are the affected sources?

There are currently 93 portland cement manufacturing 

facilities located in the U.S. and Puerto Rico that we expect to 

be affected by these proposed amendments. In 2005, these 

facilities operated 152 cement kilns and associated clinker 

coolers. We have no estimate of the number of raw material 

dryers that are separate from the kilns.

Based on capacity expansion data provided by the Portland 

Cement Association, we anticipate that 20 new kilns and 

associated clinker coolers will be built in the five years after 

the promulgation of final standards representing 24 million tpy 

of clinker capacity. Some of these new kilns will be built at 

existing facilities and some at new greenfield facilities. The 

location of the kiln (greenfield or currently existing facility) 

has no bearing on our estimated cost and environmental impacts. 

We based new kiln impacts on a 1.2 million tpy clinker 

kiln. This kiln is the smallest size anticipated for new kilns 

based on kilns built in the last five years or currently under 

construction. Using the smallest anticipated kiln size provides 
146

a conservative estimate of costs because control costs per unit 

of capacity tend to be higher for smaller kilns.

B. How are the impacts for this proposal evaluated?

For these proposed Portland Cement NESHAP amendments, the 

EPA utilized three models to evaluate the impacts of the 

regulation on the industry and the economy. Typically in a 

regulatory analysis, EPA determines the regulatory options 

suitable to meet statutory obligations under the CAA. Based on 

the stringency of those options, EPA then determines the control 

technologies and monitoring requirements that may be selected to 

comply with the regulation. This is conducted in an Engineering 

Analysis. The selected control technologies and monitoring 

requirements are then evaluated in a cost model to determine the 

total annualized control costs. The annualized control costs 

serve as inputs to an Economic Impact Analysis model that

evaluates the impacts of those costs on the industry and society 

as a whole. 

The Economic Impact Analysis model uses a single-period 

static partial-equilibrium model to compare a pre-policy cement 

market baseline with expected post-policy outcomes in cement 

markets. This model was used in previous EPA analyses of the 

portland cement industry (EPA, 1998; EPA, 1999b). The benchmark 

time horizon for the analysis is assumed to be short and 

producers have some constraints on their flexibility to adjust 
147

factors of production. This time horizon allows us to capture 

important transitory impacts of the program on existing 

producers. The model uses traditional engineering costs analysis 

as “exogenous” inputs (i.e., determined outside of the economic 

model) and computes the associated economic impacts of the 

proposed regulation.

For the Portland Cement NESHAP, EPA also employs the 

Industrial Sector Integrated Solutions (ISIS) model which 

conducts both the engineering cost analysis and the economic 

analysis in a single modeling system. The ISIS model is a 

dynamic and integrated model that simulates potential decisions 

made in the cement industry to meet an environmental policy

under a regulatory scenario. ISIS simultaneously estimates 1) 

optimal industry operation to meet the demand and emission 

reduction requirements, 2) the suite of control technologies 

needed to meet the emission limit, 3) the engineering cost of 

controls, and 4) economic impacts of demand response of the 

policy, in an iterative loop until the system achieves the 

optimal solution. More information on this model can be found 

in the ISIS Technical Support Document (TSD). The peer review 

of the ISIS model will be available at http://www.epa.gov/ttn at 

a future date. 

In a Technical Memo to the docket, we provide a comparison 

of these models to provide an evaluation of how the differences 
148

between the models may impact the resulting estimates of the 

impacts of the regulation. For example, the Engineering 

Analysis and Economic Impact Analysis evaluate a snapshot of 

implementation of the proposed rule in a given year (i.e., 2018, 

based on 2005 dollars) while ISIS evaluates impacts of 

compliance dynamically over time (i.e., 2013-2018). In general, 

given the optimization nature of ISIS, ISIS accounts for more 

flexibility when estimating the impacts of the regulation. For 

example, when optimizing to meet an emission limit, ISIS allows 

for the addition of new kilns, as well as kiln retirements, 

replacements, and expansions and the installation of controls. 

In the Engineering Analysis the existing kiln population is 

assumed to be constant even though normal kiln retirements 

occur. Overall, we anticipate the total control costs from the 

Engineering Analysis to be higher than that of ISIS. With 

higher cost estimates serving as the basis for the Economic 

Impact Analysis along with other modeling differences, we expect 

the results presented from the EIA model will be higher in 

impact than those presented by ISIS. 

In addition, we have not yet developed ISIS modules to 

calculate non-air environmental impacts and energy impacts. 

Therefore, these sections only contain impacts calculated by the 

traditional engineering methods 
149

C. What are the air quality impacts?

For the proposed Portland Cement NESHAP, EPA estimated the 

emission reductions that would occur due to the implementation 

of the proposed emission limits. EPA estimated emission 

reductions based on the control technologies selected by the 

engineering analysis. These emission reductions are based on 

2005 emission baselines.

Under the proposed limit for mercury, we have estimated 

that the emissions reductions would be 13,400 lb/yr for existing 

kilns. Based on our 1.2 million tpy model kiln, mercury 

emissions would be reduced by 149 lb/yr for each new kiln, or 

about 3,000 lb/yr 5 years after promulgation of the final 

standards.

Under the proposed limits for THC, we have estimated that 

the emissions reductions would be 14,000 tpy for existing kilns, 

which represent an organic HAP reduction of 3,360 tpy. For new 

kilns, THC emissions would be reduced by 39 tpy per kiln or 

about 800 tpy 5 years after promulgation of the final standard. 

This represents an organic HAP reduction of 192 tpy.

Under the proposed limit for HCl, we have estimated that 

emissions would be reduced by 3,000 tpy for existing kilns. 

Emissions of HCl from new kilns would be 45 tpy per kiln or 900

tpy 5 years after promulgation of the final standards.
150

The proposed emission limits for PM represent a lowering of 

the PM limit from 0.5 lb/ton of clinker to 0.085 lb/ton of 

clinker for existing kilns and for new kilns, a lowering to 

0.080 lb/ton of clinker. We have estimated that PM emissions 

would be reduced by 10,300 tpy for existing kilns. For new 

kilns, emission reductions would be 160 tpy per kiln, or about 

3,200 tpy 5 years after promulgation of the final standards.

The proposed standards for mercury, THC and HCl will also 

result in concurrent control of SO2 emissions. For kilns that use 

an RTO to comply with the THC emissions limit it is necessary to 

install an alkaline scrubber upstream of the RTO to control acid 

gas and to provide additional control of PM and to avoid 

plugging and fouling of the RTO. Scrubbers will also be used to 

control HCl and mercury emissions. Reductions in SO2 emissions 

associated with controls for mercury, THC and HCl are estimated 

at 1,600 tpy, 11,700 tpy, and 106,000 tpy, respectively. Total 

reduction in SO2 emissions from existing kilns would be an 

estimated 119,300 tpy. A new 1.2 million tpy kiln equipped with 

a scrubber will reduce SO2 emissions by 1,000 tpy on average or 

about 20,000 tpy in the fifth year after promulgation of the 

final standards.

These controls will also reduce emissions of secondary PM2.5

(and coarse PM – PM10-2.5 as well). This is PM that results from 
151

atmospheric transformation processes of precursor gases, 

including SO2.

In addition to this traditional estimation of emission 

reductions, EPA employed the ISIS model to estimate emission 

reductions. The estimation of emission reductions in the ISIS 

model accounts for the optimization of the industry and includes 

the addition of new kilns, kiln retirements, replacements, and 

expansions as well as installation of controls. Using the ISIS 

model, in 2013 we estimate reductions of 12,000 lbs of mercury, 

11,951 tons of THC, 2,791 tons of HCl, 10,554 tons of PM and 

163,309 tons of SO2 compared to total emissions in 2005. More 

information on the ISIS model and results can be found in the

ISIS TSD and in a Technical Memo to the docket.

D. What are the water quality impacts?

We estimated no water quality impacts for the proposed 

amendments. The requirements that might result in the use of 

alkaline scrubbers will produce a scrubber slurry liquid waste 

stream. However, we assume the scrubber slurry produced will be 

dewatered and added back into the cement-making process as 

gypsum. Water from the dewatering process will be recycled back 

to the scrubber. The four facilities that currently use wet 

scrubbers in this industry report no water releases at any time. 

However, if the use of scrubbers becomes more widespread there 

could be a potential for a water release due to system purges. 
152

We are requesting comment on what, if any, regulations might 

apply, and if we should add any requirements to this rule to 

prevent or control these purges. The addition of scrubbers will 

increase water usage by about 2,789 million gallons per year. 

For a new 1.2 million tpy kiln, water usage will be 36 million 

gallons per year or 720 million gallons per year 5 years after 

promulgation of the final standards. 

We note that some preproposal commenters have stated that 

some new and existing facilities may be located in areas where 

there is not sufficient water to operate a wet scrubber. 

However, we are not mandating the use of wet scrubber technology 

in these regulations, and we believe that sufficient alternative 

controls exist for mercury and acid gas controls that this issue 

would not preclude a facility from meeting these proposed 

emissions limits. However, we are also soliciting comment on 

this issue. 

E. What are the solid waste impacts?

The potential for solid waste impacts are associated with 

greater PM control for kilns, waste generated by ACI systems and 

solids resulting from solids in scrubber slurry water. As 

explained above, little or no solid waste is expected from the 

generation of scrubber slurry. The PM captured in the kiln 

fabric filter (cement kiln dust) is essentially recaptured raw 

material, intermediate materials, or product. Captured PM is 
153

typically recycled back to the kilns to the maximum extent 

possible. We estimate that any additional PM captured would 

also be recycled to the kiln because facilities minimize CKD 

disposed of as solid waste to the minimum required to maintain 

product quality. Increasing the amount of PM capture should not 

affect the minimum amount of PM required to be wasted. Where 

equipped with an alkali bypass, the bypass will have a separate 

PM control device and that PM is typically disposed of as solid 

waste. An alkali bypass is not required on all kilns. Where 

one is present, the amount of solid waste generated from the 

alkali bypass is minimal, usually about 1 percent of total CKD

in control devices, because the bypass gas stream is a small 

percentage of total kiln exhaust gas flow and the bypass gas 

stream does not contact the feed stream in the raw mill. 

Waste collected in the polishing baghouse associated with

ACI that might be added for mercury or THC control cannot be 

recycled to the kiln and would be disposed of as solid waste. 

An estimated 120,400 tpy of solid waste would be generated from 

the use of ACI systems on existing kilns. Each new kiln 

equipped with an ACI system would be expected to generate 1,800 

tons of solid waste per kiln or, assuming 14 of the 20 new kilns 

would add ACI systems, about 25,000 tpy in the fifth year after 

promulgation of the final standards.
154

In addition to the solid waste impacts described above,

these is a potential for an increase in solid waste if a 

facility elects to control mercury emission by increasing the 

amount of CKD wasted rather than returned to process. This will 

be a site-specific decision, and we have no data to estimate the 

potential solid waste that may be generated by this practice. 

However, we expect the total amount to be small for two reasons. 

First, wasting cement kiln dust for mercury control represents a 

significant expense to a facility because they are essentially 

wasting either raw materials or product. So we anticipate this 

option will not be used if the amount of CKD wasted would be 

large. Second, we believe that cement manufacturers will add 

the additional CKD to the finish mill to the maximum extent 

possible rather then waste the material. 

F. What are the secondary impacts?

Indirect or secondary air quality impacts include impacts 

that would result from the increased electricity usage 

associated with the operation of control devices as well as 

water quality and solid waste impacts (which were just 

discussed) that would occur as a result of these proposed 

revisions. We estimate these proposed revisions would increase 

emissions of criteria pollutants from utility boilers that 

supply electricity to the portland cement facilities. We 

estimate increased energy demand associated with the 
155

installation of scrubbers, ACI systems, and RTO. The increases 

for existing kilns are estimated to be 1,700 tpy of NOx, 800 tpy 

of CO, 3,000 tpy of SO2 and about 80 tpy of PM. For new kilns 

(assuming that of the 20 new kilns to start up in the 5 years 

following promulgation of the final standard 20 will add 

alkaline scrubbers, 2 will add an RTO, 14 will install ACI 

systems, and 20 will install membrane bags instead of cloth bags 

in their baghouses), increases in secondary air pollutants are 

estimated to be 400 tpy of NOx, 200 tpy of CO, 700 tpy of SO2 and 

20 tpy of PM. We also estimated increases of greenhouse gas 

emissions (chiefly CO2) to be 800,000 tpy (existing kilns) and 

200,000 tpy (new kilns). 

G. What are the energy impacts?

The addition of alkaline scrubbers, ACI systems, and RTO 

added to comply with the proposed amendments will result in 

increased energy use due to the electrical requirements for the 

scrubber and ACI systems and increased fan pressure drops, and 

natural gas to fuel the RTO. We estimate the additional national 

electrical demand to be 730 million kWhr per year and the 

natural gas use to be 700,000 MMBtu per year for existing kilns. 

For new kilns, assuming of the 20 new kilns to start up in the 5 

years following promulgation of the final standard that 20 will 

add alkaline scrubbers, 2 will add an RTO, and 14 will install 

ACI systems, the electrical demand is estimated to be 180 
156

million kWhr per year and the natural gas use to be 175,000

MMBtu per year.

H. What are the cost impacts?

Under the proposed amendments, existing kilns are expected 

to add one or more control devices to comply with the proposed 

emission limits. In addition, each kiln would be required to 

install CEMS to monitor mercury, THC and HCl while bag leak 

detector (BLD) would be required to monitor performance of all 

baghouses.

We performed two separate cost analyses for this proposed 

rule. In the engineering cost analysis we estimated the cost of 

the proposed amendments based on the type of control device that 

was assumed to be necessary to comply with the proposed emission 

standards. Based on baseline emissions of mercury, THC, HCl and 

PM for each kiln and the removal efficiency necessary to comply 

with the proposed emission limit for each HAP, an appropriate

control device was identified. In assigning control devices to 

each kiln where more than one control device would be capable of 

reducing emissions of a particular HAP below the limit, we 

assumed that the least costly control would be installed. For 

example, if a kiln could use either a scrubber or ACI to comply 

with the proposed limit for mercury, it was assumed that ACI 

would be selected over a scrubber because an ACI system would be 

less costly. ACI also is expected to achieve a higher removal 
157

efficiency than a scrubber for mercury. In some instances, a 

more expensive technology was considered appropriate because the 

selected control reduced emissions of multiple pollutants. For 

example, even though ACI would be less costly than a scrubber 

for controlling mercury, if the kiln also had to reduce HCl 

emissions, we assumed that a scrubber would be applied to 

control HCl as well as mercury because ACI would not control 

HCl. However, for many kilns, our analysis assumes that 

multiple controls will have to be added because more than one 

control will be needed to control all HAP. For example, ACI may 

be considered necessary to meet the limits for THC and/or 

mercury. For the same kiln, a scrubber would also be required 

to reduce HCl emissions. In this case we would allocate the 

cost of the control to controlling HCl emissions, not to the 

cost of controlling mercury emissions. In addition, once we 

assigned a particular control device in most cases we assumed 

mercury and THC emissions reductions would equal the control 

device efficiency, and not the minimum reduction necessary to 

meet the emissions limit. We believe this assumption is 

warranted because it matches costs with actual emissions 

reductions. In the case of PM and HCl, we assumed the 

controlled facility would emit at the average level necessary to 

meet the standard (i.e., we assumed for PM that the controlled 

facility would emit at 0.01 lb/ton clinker, the average emission 
158

level, not 0.085 lb/ton clinker, the actual emissions limit), 

because the proposed emissions levels are extremely low. 

In a separate analysis performed using the ISIS model, we 

input into ISIS the baseline and controlled emissions rates for 

each pollutant, along with the maximum percent reduction 

achievable for a particular control technology, and allowed ISIS 

to base the control required on optimizing total production 

costs. In addition, the ISIS model accounts for normal kiln 

retirements that would occur even in the absence of any 

regulatory action (i.e., as new kiln come on-line, older less 

efficient and more costly to operate kilns are retired). In the 

first cost analysis, total national annual costs assume that all 

kilns currently operating continue to operate while 20 new kilns 

come on-line.

Table 8 presents the resulting add-on controls each 

approach estimated was necessary to meet the proposed emissions 

limits.

Table 8. Control Installation Comparison

LSW ACI LWS+ACI RTO MB FF WS+RTO

Engineering 

Analysis

5 36 111 0 10 5 12

ISIS Model 4 26 93 14 0 0 0

 In the engineering analysis we estimated the total 

capital cost of installing alkaline scrubbers and ACI systems 

for mercury control, including monitoring systems, would be $71
159

million with annualized cost of $27 million. The estimated 

capital cost of installing ACI systems and RTO/scrubbers to 

reduce THC emissions would be $355 million with annualized cost 

of $110 million. The capital cost of adding scrubbers for the 

control of HCl is estimated to be $766 million with annualized 

cost of $124 million. The capital cost of adding membrane bags 

to existing baghouse and the replacement of ESP’s with baghouses 

would be $56 million with annualized cost of $17 million. The 

total capital cost for the proposed amendments would be an 

estimated $1.23 billion with an annualized cost of $275 million.

The estimated emission control capital cost per new 1.2 

million tpy kiln is $16.6 million and the annualized costs are

estimated at $1.25 million for mercury control, $1.0 million for 

THC control, $1.8 million for HCl control and $270,000 for PM 

control. National annualized cost by the end of the fifth year 

will be an estimated $86.4 million.

In the ISIS results, we are not able to separate costs by 

pollutant because the model does an overall optimization of the 

production and air pollution control costs. The total annual 

costs of the ISIS model are $167 million in 2013, and are 

anticipated to increase to $180 million in 2018. These impacts 

assume that in 2013 7 new kilns are installed and net 10 kilns 

are retired. These retirements include two kilns that we have 

determined may close due to not being able to meet the mercury 
160

emission limits due to unusually high mercury contents in their 

proprietary quarries (i.e., the mercury content of the raw 

material at limestone quarries).

I. What are the economic impacts?

EPA employed both a partial-equilibrium economic model and 

the ISIS model to analyze the impact on the industry and the 

economy. 

The Economic Impact Analysis model estimates the average 

national price for portland cement could be 4 percent higher 

with the NESHAP, or $3.30 per metric ton, while annual domestic 

production may fall by 8 percent, or 7 million tons per year. 

Because of higher domestic prices, imports are expected to rise 

by 2 million metric tons per year. 

As domestic production falls, cement industry revenues are 

projected to decline by 4 percent, or $340 million. Overall, net 

production costs also fall by $140 million with compliance cost 

increases ($240 million) offset by cost reductions associated 

with lower cement production. Operating profits fall by $200 

million, or 16 percent. Other projected impacts include reduced 

demand for labor. Employment falls by approximately 8 percent, 

or 1,200 employees. EPA identified six domestic plants with 

negative operating profits and significant utilization changes 

that could temporarily idle until market demand conditions 

improve. The plants are small capacity plants with unit 
161

compliance costs close to $5 per ton and $50 million total 

change in operating profits. Since these plants account for 

approximately 2.5 percent of domestic capacity, a decision to 

permanently shut down these plants would reduce domestic supply 

and lead to additional projected market price increases.

The estimated domestic social cost of the proposed 

amendments is $684 million. There is an estimated $89 million 

surplus gain for other countries producing cement. The social 

cost estimates are significantly higher than the engineering 

analysis estimates, which estimated annualized costs of $370 

million. This is a direct consequence of EPA’s assumptions about 

existing domestic plants’ pricing behavior. Under baseline 

conditions without regulation, the existing domestic cement 

plants are assumed to choose a production level that is less 

than the level produced under perfect competition. The 

imposition of additional regulatory costs tends to widen the gap 

between price and marginal cost in these markets and contributes 

to additional social costs. For more detail see the Regulatory 

Impact Analysis (RIA).

Using the ISIS model, we estimate cement demand to drop 2.9

percent in 2013 or 3.9 million tons with an average annual drop 

in demand at 2.3 percent or 3.2 million tons per year during the 

2013-2018 time period. The drop in demand will affect the level 

of imports, and imports are likely to rise slightly over the 
162

policy horizon. In 2013, imports rise 2.6 percent or 0.92

million tons with an annual average of 2.3 percent or 0.89

million tons per year throughout the 2013-2018. ISIS estimates 

the average national price for portland cement in the 2013-2018 

time period to be 0.2 percent higher with the NESHAP, or $0.20

per metric ton. However, some markets could see an increase by 

up to 4.5 percent. Total annualized control cost for the 

proposed NESHAP amendments is projected to be $167 million in 

2013, and is expected to increase to $180 million in 2018, as 

additional new units come online to meet the projected increase 

in demand. 

With respect to the baseline case in 2013, ISIS identified 

a net retirement of 5.2 million tons of capacity. The 

retirements affect 10 kilns at 8 facilities. As a result of the 

proposed NESHAP amendments, the cost to produce a ton of cement 

(production, imports, transportation and control technology) 

increases from $56.11 per ton at baseline to $57.83 per ton as a 

result of these proposed amendments ($1.72/ton), resulting in an 

increase of about 3 percent over the analysis period of 2013 to 

2018. With respect to baseline in 2013 ISIS projects the 

revenue of the cement industry to fall by 8 percent or about 

$615 million. More information on this model can be found in 

the ISIS TSD and in a Technical Memo to the docket.

J. What are the benefits?
163

We estimate the monetized benefits of this proposed NESHAP 

to be $4.4 billion to $11 billion (2005$, 3percent discount 

rate) in the year of full implementation (2013); using alternate 

relationships between PM2.5 and premature mortality supplied by 

experts, higher and lower benefits estimates are plausible, but 

most of the expert-based estimates fall between the two 

estimates we present above.59 The benefits at a 7 percent

discount rate are $4.0 billion to $9.7 billion (2005$). We base 

the estimate of human health benefits derived from the PM2.5 and 

PM2.5 precursor emission reductions on the approach and 

methodology laid out in the TSD that accompanied the RIA for the 

revision to the National Ambient Air Quality Standard for 

Ground-level Ozone (NAAQS), March 2008 with several updates 

explained below. We generated estimates that represent the 

total monetized human health benefits (the sum of premature 

mortality and morbidity) of reducing PM2.5 and PM2.5 precursor

emissions. A summary of the monetized benefits estimates at 

discount rates of 3 percent and 7 percent is in Table 7 of this 

preamble. 

 

59 Roman et al, 2008. Expert Judgment Assessment of the Mortality Impact of 

Changes in Ambient Fine Particulate Matter in the U.S. Environ. Sci. 

Technol., 42, 7, 2268 – 2274.
164

Table 7. Summary of the Monetized Benefits Estimates for the 

Proposed Portland Cement NESHAP

Pollutant

Emission 

reductions 

(tons)

Total 

monetized 

benefits 

(millions of 

2005 dollars, 

3% Discount)1

Total 

monetized 

benefits 

(millions of 

2005 dollars, 

7 percent

Discount)1

Direct PM2.5 6,300 $1,200 to 

$2,800

$1,000 to 

$2,500

PM2.5

precursors

140,000 $3,300 to 

$8,000

$3,000 to 

$7,200

Grand total: $4,400 to 

$11,000

$4,000 to 

$9,700

1All estimates are for the analysis year (full implementation, 

2013), and are rounded to two significant figures so numbers may 

not sum across rows. PM2.5 precursors reflect emission reductions 

of SOx. All fine particles are assumed to have equivalent 

health effects, and the monetized benefits incorporate the 

conversion from precursor emissions to ambient fine particles. 

These monetized benefits do not include HAP reductions,

additional emission reductions that would occur if cement 

facilities temporarily idle or reduce capacity utilization as a 

result of this regulation, or the unquantifiable amount of 

reductions in condensable PM.

The specific estimates of benefits per ton of pollutant 

reductions included in this analysis are largely driven by the 

concentration response function for premature mortality. 

Experts have advised EPA to consider a variety of assumptions, 

including estimates based both on empirical (epidemiological) 

studies and judgments elicited from scientific experts, to 

characterize the uncertainty in the relationship between PM2.5 

concentrations and premature mortality. For this proposed 

NESHAP we cite two key empirical studies, one based on the 
165

American Cancer Society cohort study62 and the extended Six 

Cities cohort study63. Alternate models identified by experts 

describing the relationship between PM2.5 and premature mortality 

would yield higher and lower estimates, but most of the expertbased estimates fall between the two epidemiology-based 

estimates (Roman et al. 2008). 

EPA has incorporated several updates to the benefit-per-ton estimates, including two technical 

updates and removing the assumption regarding thresholds in the health impact function. 

Removing thresholds is supported by a wide body of peer-reviewed literature on the health 

effects of short and longer term PM exposures. Approximately 75 percent of the 

difference between the old methodology and the new methodology 

for this rule is due to removing thresholds with 25 percent due 

to the two technical updates, but this percentage would vary 

depending on the combination of emission reductions from 

different sources and PM2.5 precursor pollutants. For more 

information on the updates to the benefit-per-ton estimates, 

please refer to the RIA for this proposed rule that is available 

in the docket.

To generate the benefit-per-ton estimates, we used a model 

to convert emissions of direct PM2.5 and PM2.5 precursors into 

 

62 Pope et al, 2002. “Lung Cancer, Cardiopulmonary Mortality, 

and Long-term Exposure to Fine Particulate Air Pollution.” 

Journal of the American Medical Association 287:1132-1141

63 Laden et al, 2006. “Reduction in Fine Particulate Air 

Pollution and Mortality.” American Journal of Respiratory and 

Critical Care Medicine. 173: 667-672
166

changes in PM2.5 air quality and another model to estimate the 

changes in human health based on that change in air quality. 

Finally, the monetized health benefits were divided by the 

emission reductions to create the benefit-per-ton estimates. 

Even though all fine particles are assumed to have equivalent 

health effects, the benefit-per-ton estimates vary between 

precursors because each ton of precursor reduced has a different 

propensity to form PM2.5. For example, SOX has a lower benefitper-ton estimate than direct PM2.5 because it does not form as 

much PM2.5, thus the exposure would be lower, and the monetized 

health benefits would be lower. 

This analysis does not include the type of detailed 

uncertainty assessment found in the 2006 PM2.5 NAAQS RIA because 

we lack the necessary air quality input and monitoring data to 

run the benefits model. However, the 2006 PM2.5 NAAQS benefits 

analysis provides an indication of the sensitivity of our 

results to the use of alternative concentration response 

functions, including those derived from the PM expert 

elicitation study. 

The annualized costs of this rulemaking are estimated at 

$694 million (2005$) in the year of full implementation, and the 

benefits are estimated at $4.4 billion to $11 billion (2005$, 3

percent discount rate) for that same year. The benefits at a 7

percent discount rate are $4.0 billion to $9.7 billion (2005$). 
167

Thus, net benefits of this rulemaking are estimated at $3.7 

billion to $11 billion (2005$, 3 percent discount rate); using 

alternate relationships between PM2.5 and premature mortality 

supplied by experts, higher and lower benefits estimates are 

plausible, but most of the expert-based estimates fall between 

the two estimates we present above. The net benefits at a 7

percent discount rate are $3.3 billion to $9.0 billion (2005$). 

EPA believes that the benefits are likely to exceed the costs by 

a significant margin even when taking into account the 

uncertainties in the cost and benefit estimates. It should be 

noted that the benefits estimates provided above does not 

include benefits from improved visibility, coarse PM emission 

reductions, or other hazardous air pollutants such as mercury 

and hydrochloric acid, additional emission reductions that would 

occur if cement facilities temporarily idle or reduce capacity 

utilization as a result of this regulation, or the 

unquantifiable amount of reductions in condensable PM. We do 

not have sufficient information or modeling available to provide 

such estimates for this rulemaking. 

For more information, please refer to the RIA for this 

proposed rule that is available in the docket.

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review
168

Under Executive Order 12866 (58 FR 51735, October 4, 1993), 

this action is a “significant regulatory action” because it may 

raise novel legal or policy issues. Accordingly, EPA submitted 

this action to OMB for review under Executive Order 12866, and 

any changes made in response to OMB recommendations have been 

documented in the docket for this action.

B. Paperwork Reduction Act

The information collection requirements in this proposed 

rule have been submitted for approval to the OMB under the 

Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The Information 

Collection Request (ICR) document prepared by EPA has been 

assigned EPA ICR number 1801.07.

In most cases, new and existing kilns and in-line kiln/raw 

mills at major and area sources that are not already subject to 

emission limits for THC, mercury, and PM would become subject to 

the limits and associated compliance provisions in the current 

rule. New compliance provisions for mercury would remove the 

current requirement for an initial performance test coupled with 

monitoring of the carbon injection rate. Instead, plants would 

monitor mercury emissions by determining the monthly and rolling 

12-month mercury throughput using a material balance procedure. 

The procedure would require daily sampling of process inputs 

(feed, baghouse dust, fuels) and analysis of the mercury 

concentration in a monthly composite sample. Records of all 
169

calculations and data would be required. New compliance 

procedures would also apply to area sources subject to a PM 

limit in a format of lbs/ton of clinker. The owner or operator 

would be required to install and operate a weight measurement 

system and keep daily records of clinker production instead of 

the current requirement to install and operate a PM CEMS. The 

owner or operator would be required to conduct an initial PM 

performance test and repeat performance tests every 5 years. 

Cement plants also would be subject to new limits for HCl and 

associated compliance provisions which include compliance tests 

using EPA Method 321 and continuous monitoring for HCl for 

facilities that do not use a wet scrubber for HCl control. 

These requirements are based on the recordkeeping and reporting 

requirements in the NESHAP General Provisions (40 CFR part 63, 

subpart A) which are mandatory for all operators subject to 

national emission standards. These recordkeeping and reporting 

requirements are specifically authorized by section 114 of the 

CAA (42 U.S.C. 7414). All information submitted to EPA pursuant 

to the recordkeeping and reporting requirements for which a 

claim of confidentiality is made is safeguarded according to EPA 

policies set forth in 40 CFR part 2, subpart B.

The annual burden for this information collection averaged 

over the first 3 years of this ICR is estimated to total 44,656

labor-hours per year at a cost of $4.1 million per year. The 
170

average annualized capital costs are estimated at $53.7 million

per year and average operation and maintenance costs are 

estimated at $174,000 per year. Burden is defined at 5 CFR 

1320.3(b).

An agency may not conduct or sponsor, and a person is not 

required to respond to a collection of information unless it 

displays a currently valid OMB control number. The OMB control 

numbers for EPA’s regulations are listed in 40 CFR part 9.

To comment on the Agency’s need for this information, the 

accuracy of the provided burden estimates, and any suggested 

methods for minimizing respondent burden, EPA has established a 

public docket for this proposed rule, which includes this ICR, 

under Docket ID number EPA-HQ-OAR-2002-0051. Submit any 

comments related to the ICR for this proposed rule to EPA and 

OMB. See ADDRESSES section at the beginning of this document 

for where to submit comments to EPA. Send comments to OMB at 

the Office of Information and Regulatory Affairs, Office of 

Management and Budget, 725 17th Street, NW, Washington, DC 20503, 

Attention: Desk Office for EPA. Since OMB is required to make 

a decision concerning the ICR between 30 and 60 days after 

[INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER], a comment 

to OMB is best assured of having its full effect if OMB receives 

it by [INSERT DATE 30 DAYS AFTER PUBLICATION IN THE FEDERAL 

REGISTER]. The final rule will respond to any OMB or public 
171

comments on the information collection requirements contained in 

this proposal.

C. Regulatory Flexibility Act

The Regulatory Flexibility Act generally requires an agency 

to prepare a regulatory flexibility analysis of any rule subject 

to notice and comment rulemaking requirements under the

Administrative Procedure Act or any other statute unless the 

agency certifies that the rule will not have a significant 

economic impact on a substantial number of small entities. 

Small entities include small businesses, small organizations, 

and small governmental jurisdictions.

For purposes of assessing the impact of this rule on small 

entities, small entity is defined as: (1) a small business 

whose parent company has no more than 750 employees (as defined 

by Small Business Administration (SBA) size standards for the 

portland cement industry, NAICS 327310); (2) a small 

governmental jurisdiction that is a government of a city, 

county, town, school district, or special district with a 

population of less than 50,000; and (3) a small organization 

that is any not-for-profit enterprise which is independently 

owned and operated and is not dominant in its field.

After considering the economic impact of this proposed rule 

on small entities, I certify that this action will not have a 

significant economic impact on a substantial number of small 
172

entities. We estimate that up to 4 of the 44 existing portland 

cement plants are small entities. One of the entities burns 

hazardous waste in its kiln and is not impacted by this proposed 

rule. 

EPA performed a screening analysis for impacts on the three 

affected small entities by comparing compliance costs to entity 

revenues. EPA’s analysis found that the ratio of compliance cost 

to company revenue for two small entities (including a tribal 

government) would have an annualized cost of between 1 percent

and 3 percent of sales. One small business would have an 

annualized cost of 4.8 percent of sales. In addition to the 

screening analysis, EPA also examined small entity effects after 

accounting for market adjustments. Under this assumption, the 

entities recover some of the regulatory program costs as the 

market price adjusts in response to higher cement production 

costs. Even after accounting for these adjustments, small entity 

operating profits fall by $4 million, or 9 percent. All three 

affected facilities are projected to continue to operate under 

with-regulation conditions. 

EPA also evaluated small business impacts using the ISIS 

model. There are a total of 7 kilns identified to be associated 

with small business facilities affected by this proposal. ISIS 

identified one of these kilns to retire in 2013 as a result of 

the proposed NESHAP. A second kiln reduces its utilization by 
173

56 percent in 2013 but recovers later in the 2013 to 2018 time 

frame as the demand increases. All the remaining small business 

kilns operate at full capacity throughout the 2013 to 2018 time 

frame. 

Although this proposed rule will not impact a substantial 

number of small entities, EPA nonetheless has tried to reduce 

the impact of this proposed rule on small entities by setting 

the proposed emissions limits at the MACT floor, the least 

stringent level allowed by law. In the case where there are 

overlapping standards between this NESHAP and the Portland 

Cement NSPS, we have exempted sources from the least stringent 

requirement thereby eliminating the overlapping monitoring, 

testing and reporting requirements by proposing that the source 

comply with only the more stringent of the standards. We 

continue to be interested in the potential impacts of this 

proposed rule on small entities and welcome comments on issues 

related to such impacts.

D. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act (UMRA), 2 

U.S.C 1531-1538, requires Federal agencies, unless otherwise 

prohibited by law, to assess the effects of their regulatory 

actions on State, local, and tribal governments and the private 

sector. Federal agencies must also develop a plan to provide 

notice to small governments that might be significantly or 
174

uniquely affected by any regulatory requirements. The plan must 

enable officials of affected small governments to have 

meaningful and timely input in the development of EPA regulatory 

proposals with significant Federal intergovernmental mandates 

and must inform, educate, and advise small governments on 

compliance with the regulatory requirements.

This rule contains a Federal mandate that may result in 

expenditures of $100 million or more for State, local, and 

tribal governments, in the aggregate, or the private sector in 

any one year. Accordingly, EPA has prepared under section 202 

of the UMRA a written statement which is summarized below.

Consistent with the intergovernmental consultation 

provisions of section 204 of the UMRA EPA has already initiated 

consultations with the governmental entities affected by this 

rule. In developing this rule, EPA consulted with small 

governments under a plan developed pursuant to section 203 of 

UMRA concerning the regulatory requirements in the rule that 

might significantly or uniquely affect small governments. EPA 

has determined that this proposed action contains regulatory 

requirements that might significantly or uniquely affect small 

governments because one of the facilities affected by the 

proposed rule is tribally owned. EPA consulted with tribal 

officials early in the process of developing this regulation to 

permit them to have meaningful and timely input into its 
175

development. EPA directly contacted the facility in question to 

insure they were apprised of this rulemaking and potential 

implications. This facility indicated they were aware of the 

rulemaking and were participating in meeting with the industry 

trade association concerning this rulemaking. The facility did 

not indicate any specific concern, and we are assuming that they 

have the same concerns as those expresses by the other nontribally owned facilities during the development of this 

proposed rule. 

Consistent with section 205, EPA has identified and 

considered a reasonable number of regulatory alternatives. EPA 

carefully examined regulatory alternatives, and selected the 

lowest cost/least burdensome alternative that EPA deems adequate 

to address Congressional concerns and to effectively reduce 

emissions of mercury, THC and PM. EPA has considered the costs 

and benefits of the proposed rule, and has concluded that the 

costs will fall mainly on the private sector (approximately $273 

million). EPA estimates that an additional facility owned by a 

tribal government will incur approximately $2.1 million in costs 

per year. Furthermore, we think it is unlikely that State, local 

and Tribal governments would begin operating large industrial 

facilities, similar to those affected by this rulemaking 

operated by the private sector.

E. Executive Order 13132: Federalism
176

Executive Order 13132 (64 FR 43255, August 10, 1999), 

requires EPA to develop an accountable process to ensure 

“meaningful and timely input by State and local officials in the 

development of regulatory policies that have federalism 

implications.” “Policies that have federalism implications” is 

defined in the Executive Order to include regulations that have 

“substantial direct effects on the States, on the relationship 

between the national government and the States, or on the 

distribution of power and responsibilities among the various 

levels of government.”

This proposed rule does not have federalism implications. 

It will not have substantial direct effects on the States, on 

the relationship between the national government and the States, 

or on the distribution of power and responsibilities among the 

various levels of government, as specified in Executive Order 

13132. None of the affected facilities are owned or operated by 

State governments. Thus, Executive Order 13132 does not apply 

to this proposed rule.

In the spirit of Executive Order 13132, and consistent with 

EPA policy to promote communications between EPA and State and 

local governments, EPA specifically solicits comment on this 

proposed action from State and local officials.

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments
177

Subject to the Executive Order 13175 (65 FR 67249, November 

9, 2000) EPA may not issue a regulation that has tribal 

implications, that imposes substantial direct compliance costs, 

and that is not required by statute, unless the Federal 

government provides the funds necessary to pay the direct 

compliance costs incurred by tribal governments, or EPA consults 

with tribal officials early in the process of developing the 

proposed regulation and develops a tribal summary impact 

statement.

EPA has concluded that this action will have tribal 

implications, because it will impose substantial direct 

compliance costs on tribal governments, and the Federal 

government will not provide the funds necessary to pay those 

costs. One of the facilities affected by this proposed rule is 

tribally owned. We estimate this facility will incur direct 

compliance costs that are between 1 to 3 percent of sales. 

Accordingly, EPA provides the following tribal summary impact 

statement as required by section 5(b). 

EPA consulted with tribal officials early in the process of 

developing this regulation to permit them to have meaningful and 

timely input into its development. EPA directly contacted the 

facility in question to insure they were apprised of this 

rulemaking and potential implications. This facility indicated 

they were aware of the rulemaking and were participating in 
178

meeting with the industry trade association concerning this 

rulemaking. The facility did not indicate any specific concern, 

and we are assuming that they have the same concerns as those 

expresses by the other non-tribally owned facilities during the 

development of this proposed rule. 

EPA specifically solicits additional comment on this 

proposed action from tribal officials.

G. Executive Order 13045: Protection of Children from 

Environmental Health Risks and Safety Risks

EPA interprets Executive Order 13045 as applying to those 

regulatory actions that concern health or safety risks, such 

that the analysis required under section 5-501 of the Order has 

the potential to influence the regulation. This proposed action 

is not subject to Executive Order 13045 because it is based 

solely on technology performance. 

H. Executive Order 13211: Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use

This proposed rule is not a “significant energy action” as 

defined in Executive Order 13211, “Actions Concerning 

Regulations That Significantly Affect Energy Supply, 

Distribution, or Use” (66 FR 28355, May 22, 2001) because it is 

not likely to have a significant adverse effect on the supply, 

distribution, or use of energy. Further, we have concluded that 

this proposed rule is not likely to have any adverse energy 
179

effects. This proposal will result in the addition of control 

equipment and monitoring systems for existing and new sources. 

We estimate the additional electrical demand to be 784 million 

kWhr per year and the natural gas use to be 672 million cubic 

feet for existing sources. At the end of the fifth year 

following promulgation, electrical demand from new sources will 

be 180 million kWhr per year and natural gas use will be 171 

million cubic feet.

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and 

Advancement Act of 1995 (“NTTAA”), Public Law No. 104-113 (15 

U.S.C. 272 note) directs EPA to use voluntary consensus 

standards (VCS) in its regulatory activities unless to do so 

would be inconsistent with applicable law or otherwise 

impractical. VCS are technical standards (e.g., materials 

specifications, test methods, sampling procedures, and business 

practices) that are developed or adopted by VCS bodies. NTTAA 

directs EPA to provide Congress, through OMB, explanations when 

the Agency decides not to use available and applicable VCS.

These proposed amendments involve technical standards. The 

EPA proposes to cite Performance Specifications 8A of 40 CFR 

part 60appendix B for THC, 12A and 12B of 40 CFR part 60 

appendix B for mercury and 15 of 40 CFR part 60 appendix B for 

HCl continuous monitor operation and maintenance. In addition 
180

EPA proposes to use the following test methods to determine 

compliance: EPA Method 5 of 40 CFR Appendix B for PM; EPA 

Method 321 of 40 CFR Appendix B for HCl; and EPA Method 320 of 

40 CFR Appendix B for organic HAP.

Consistent with the NTTAA, EPA conducted searches through 

the Enhanced NSSN Database managed by the American National 

Standards Institute (ANSI). We also contacted VCS 

organizations, and accessed and searched their databases. 

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations

Executive Order 12898 (59 FR 7629 (Feb. 16, 1994)) 

establishes Federal executive policy on environmental justice. 

Its main provision directs Federal agencies, to the greatest 

extent practicable and permitted by law, to make environmental 

justice part of their mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or 

environmental effects of their programs, policies, and 

activities on minority populations and low-income populations in 

the United States. EPA has determined that these proposed 

amendments will not have disproportionately high and adverse

human health or environmental effects on minority or low-income
National Emission Standards for Hazardous Air Pollutants From 

the Portland Cement Manufacturing Industry

Page 181 of 217

populations because they would increase the level of 

environmental protection for all affected populations without 

having any disproportionately high and adverse human health or 

environmental effects on any population, including any minority 

or low-income population. These proposed standards would reduce

emissions of mercury, THC, HCl, and PM from portland cement 

plants located at major and area sources, decreasing the amount 

of such emissions to which all affected populations are exposed.

List of Subjects in 40 CFR Part 63

Environmental protection, Air pollution control, Hazardous 

substances, Incorporation by reference, and Reporting and 

recordkeeping requirements.

Dated:

Lisa P. Jackson,

Administrator.
182

For the reasons stated in the preamble, title 40, chapter 

I, of the Code of Federal Regulations is proposed to be amended 

as follows:

PART 63--[AMENDED]

1. The authority citation for part 63 continues to read as 

follows:

Authority: 42 U.S.C. 7401, et seq.

Subpart LLL—[Amended]

2. Section 63.1340 is amended as follows:

a. By revising paragraph (a);

b. By revising paragraphs (b)(1) through (b)(8); and

c. By revising paragraph (c).

§63.1340 Applicability and designation of affected sources.

(a) The provisions of this subpart apply to each new and 

existing portland cement plant which is a major source or an 

area source as defined in §63.2.

(b) * * * 

(1) Each kiln and each in-line kiln/raw mill, including 

alkali bypasses, except for kilns and in-line kiln/raw mills 

that burn hazardous waste and are subject to and regulated under 

subpart EEE of this part;

(2) Each clinker cooler at any portland cement plant;

(3) Each raw mill at any portland cement plant;

(4) Each finish mill at any portland cement plant;
183

(5) Each raw material dryer at any portland cement plant;

(6) Each raw material, clinker, or finished product storage 

bin at any portland cement plant;

(7) Each conveying system transfer point including those 

associated with coal preparation used to convey coal from the 

mill to the kiln at any portland cement plant; and

(8) Each bagging and bulk loading and unloading system at 

any portland cement plant.

(c) Crushers are not covered by this subpart regardless of 

their location.

* * * * *

3. Section 63.1341 is amended by adding definitions for 

“Clinker,” “Crusher,” “New Source” and “Total organic HAP” in 

alphabetic order to read as follows:

§63.1341 Definitions.

* * * * *

Clinker means the product of the process in which limestone 

and other materials are heated in the kiln and is then ground 

with gypsum and other materials to form cement.

* * * * *

Crusher means a machine designed to reduce large rocks from 

the quarry into materials approximately the size of gravel. 

* * * * * *
184

New Source means any source that commences construction

after December 2, 2005 for purposes of determining the 

applicability of the kiln in-line raw mill/kiln, clinker cooler 

and raw material dryer emissions limits for mercury, THC, and 

HCl. New source means any source that commences construction

after [INSERT THE DATE OF PUBLICATION OF THIS PROPOSED RULE IN 

THE FEDERAL REGISTER] for purposes of determining the 

applicability of the kiln in-line raw mill/kiln AND clinker 

cooler emissions limits for PM.

* * * * *

Total organic HAP means, for the purposes of this subpart, 

the sum of the concentrations of compounds of formaldehyde, 

benzene, toluene, styrene, m-xylene, p-xylene, o-xylene, 

acetaldehyde, and naphthalene as measured by EPA Test Method 25 

or 25A. Only the measured concentration of the listed analytes 

that are present at concentrations exceeding one-half the 

quantitation limit of the analytical method are to be used in 

the sum. If any of the analytes are not detected or are 

detected at concentrations less than one-half the quantitation 

limit of the analytical method, the concentration of those 

analytes will be assumed to be zero for the purposes of 

calculating the total organic HAP for this subpart.

* * * * *

4. Section 63.1343 is amended:
185

a. By revising paragraph (a);

b. By revising paragraph (b) introductory text,

c. By revising paragraph (b)(1);

d. By adding paragraphs (b)(4) through (b)(6);

e. By revising paragraph (c) introductory text;

f. By revising paragraphs (c)(1), (c)(4) and (c)(5); and

g. By adding paragraph (c)(6),

h. By removing paragraphs (d) and (e) to read as follows:

§63.1343 Standards for kilns and in-line kiln/raw mills.

(a) General. The provisions in this section apply to each 

kiln, each in-line kiln/raw mill, and any alkali bypass 

associated with that kiln or in-line kiln/raw mill. All dioxin 

furan (D/F) and THC emission limits are on a dry basis, 

corrected to 7 percent oxygen. All total hydrocarbon (THC) 

emission limits are measured as propane.

(b) Existing kilns located at major or area sources. No 

owner or operator of an existing kiln or an existing in-line 

kiln/raw mill located at a facility that is subject to the 

provisions of this subpart shall cause to be discharged into the 

atmosphere from these affected sources, any gases which:

(1) Contain particulate matter (PM) in excess of 0.085

pounds per ton of clinker. When there is an alkali bypass 

associated with a kiln or in-line kiln/raw mill, the combined PM 

emissions from the kiln or in-line kiln/raw mill and the alkali 
186

bypass stack are subject to this emission limit. Kiln, or inline kiln/raw mills that combine the clinker cooler exhaust with 

the kiln exhaust for energy efficiency purposes and send the 

combined exhaust to the PM control device as a single stream may 

meet and alternative PM emissions limit. This limit is 

calculated using the following equation: 

PM alt = 0.0067 x 1.65 x (Qk + Qc)/7000 (Eq. 1)

Where: 0.0067 is the PM exhaust concentration 

equivalent to 0.085 lb per ton clinker where clinker 

cooler and kiln exhaust gas are not combined. 

Qk is the exhaust flow of the kiln (dscf/ton raw 

 feed)

Qc is the exhaust flow of the clinker cooler (dscf/ton 

 raw feed)

* * * * *

(4) Contain THC in excess of 7 ppmv or total organic HAP 

in excess of 2 ppmv from the main exhaust of the kiln or in-line 

kiln/raw mill.

(5) Contain mercury (Hg) in excess of 43 lb per million 

tons of clinker. When there is an alkali bypass associated with 

a kiln or in-line kiln/raw mill, the combined Hg emissions from 

the kiln or in-line kiln/raw mill and the alkali bypass are 

subject to this emission limit. 
187

(6) Contain hydrogen chloride (HCl) in excess of 2 ppmv

from the main exhaust of the kiln or in-line kiln/raw mill if 

the kiln or in-line kiln/raw mill is located at a major source 

of HAP emissions.

(c) New or reconstructed kilns located at major or area 

sources. No owner or operator of a new or reconstructed kiln or 

new or reconstructed inline kiln/raw mill located at a facility 

subject to the provisions of this subpart shall cause to be 

discharged into the atmosphere from these affected sources any 

gases which:

(1) Contain PM in excess of 0.080 pounds per ton of 

clinker. When there is an alkali bypass associated with a kiln 

or in-line kiln/raw mill, the combined PM emissions from the 

kiln or in-line kiln/raw mill and the alkali bypass stack are 

subject to this emission limit. Kiln, or in-line kiln/raw mills 

that combine the clinker cooler exhaust with the kiln exhaust 

for energy efficiency purposes and send the combined exhaust to 

the PM control device as a single stream may meet an alternative 

PM emissions limit. This limit is calculated using the

following equation: 

PM alt = 0.0063 x 1.65 x (Qk + Qc)/7000 (Eq. 2)

Where: 0.0063 is the PM exhaust concentration 

equivalent to 0.080 lb per ton clinker where clinker 

cooler and kiln exhaust gas are not combined. 
188

Qk is the exhaust flow of the kiln (dscf/ton raw 

 feed)

Qc is the exhaust flow of the clinker cooler (dscf/ton 

 raw feed)

* * * * *

(4) Contain THC in excess of 6 ppmv, or total organic HAP 

in excess of 1 ppmv, from the main exhaust of the kiln, or main 

exhaust of the in-line kiln/raw mill. 

(5) Contain Hg from the main exhaust of the kiln, or main 

exhaust of the in-line kiln/raw mill, in excess of 14 lb/million 

tons of clinker. When there is an alkali bypass associated with 

a kiln, or in-line kiln/raw mill, the combined Hg emissions from 

the kiln or in-line kiln/raw mill and the alkali bypass are 

subject to this emission limit.

(6) Contain HCl in excess of 0.1 ppmv from the main 

exhaust of the kiln, or main exhaust of the in-line kiln/raw 

mill if the kiln or in-line kiln/raw mill is located at a major 

source of HAP emissions.

5. Section 63.1344 is amended:

a. By revising paragraph (c) introductory text, 

b. By revising paragraphs (d) and (e); and

b. By removing paragraphs (f),(g) (h) and (i) to read as 

follows:

§63.1344 Operating limits for kilns and in-line kiln/raw mills.
189

* * * * *

(c) The owner or operator of an affected source subject to 

a D/F emission limitation under §63.1343 that employs carbon 

injection as an emission control technique must operate the 

carbon injection system in accordance with paragraphs (c)(1) and 

(c)(2) of this section.

* * * * *

(d) Except as provided in paragraph (e) of this section, 

the owner or operator of an affected source subject to a D/F 

emission limitation under §63.1343 that employs carbon injection 

as an emission control technique must specify and use the brand 

and type of activated carbon used during the performance test 

until a subsequent performance test is conducted, unless the 

site-specific performance test plan contains documentation of 

key parameters that affect adsorption and the owner or operator 

establishes limits based on those parameters, and the limits on 

these parameters are maintained.

(e) The owner or operator of an affected source subject to 

a D/F emission limitation under §63.1343 that employs carbon 

injection as an emission control technique may substitute, at 

any time, a different brand or type of activated carbon provided 

that the replacement has equivalent or improved properties 

compared to the activated carbon specified in the site-specific 

performance test plan and used in the performance test. The 
190

owner or operator must maintain documentation that the 

substitute activated carbon will provide the same or better 

level of control as the original activated carbon.

6. Section 63.1345 is amended by revising paragraph (a)

introductory text and paragraph (a)(1) to read as follows:

§63.1345 Standards for clinker coolers.

(a) No owner or operator of a new or existing clinker 

cooler at a facility which is a major source or an area source 

subject to the provision of this subpart shall cause to be 

discharged into the atmosphere from the clinker cooler any gases 

which:

(1) Contain PM in excess of 0.085 lb per ton of clinker

for existing sources or 0.080 lb per ton of clinker for new 

sources.

* * * * *

7. Section 63.1346 is revised to read as follows: 

§63.1346 Standards for raw material dryers.

(a) Raw material dryers that are located at facilities that 

are major sources can not discharge to the atmosphere any gases 

which:

(1) Exhibit opacity greater then 10 percent; or

(2) Contain THC in excess of 7 ppmv (existing sources) or 

6 ppmv (new sources), on a dry basis as propane corrected to 7 

percent oxygen.
191

(b) Raw Material dryers located at a facility that is an 

area source must not discharge to the atmosphere any gases which 

contain THC in excess of 7 ppmv (existing sources) or 6 ppmv 

(new sources), on a dry basis as propane corrected to 7 percent

oxygen.

8. Section 63.1349 is amended:

a. By revising paragraph (b) introductory text;

b. By revising paragraphs (b)(1)introductory text, 

(b)(1)(ii), (iii), (iv) and (vii); 

c. By revising paragraphs (b)(4) and (b)(5); 

d. By adding paragraph (b)(6);

e. By revising paragraph (c);

f. By adding paragraph (f); and

g. By adding paragraph (g) to read as follows:

§63.1349 Performance testing requirements.

* * * * *

(b) Performance tests to demonstrate initial compliance 

with this subpart shall be conducted as specified in paragraphs 

(b)(1) through (b)(7) of this section.

(1) The owner or operator of a kiln subject to limitations 

on PM emissions that is not equipped with a PM CEMS shall 

demonstrate initial compliance by conducting a performance test 

as specified in paragraphs (b)(1)(i) through (b)(1)(iv) of this 

section. The owner or operator of an in-line kiln/raw mill 
192

subject to limitations on PM emissions that is not equipped with 

a PM CEMS shall demonstrate initial compliance by conducting 

separate performance tests as specified in paragraphs (b)(1)(i) 

through (b)(1)(iv) of this section while the raw mill of the inline kiln/raw mill is under normal operating conditions and 

while the raw mill of the in-line kiln/raw mill is not 

operating. The owner or operator of a clinker cooler subject to 

limitations on PM emissions shall demonstrate initial compliance 

by conducting a performance test as specified in paragraphs 

(b)(1)(i) through (b)(1)(iii) of this section. The owner or 

operator shall determine the opacity of PM emissions exhibited 

during the period of the Method 5 (40 CFR part 60, appendix A-3)

performance tests required by paragraph (b)(1)(i) of this 

section as required in paragraphs (b)(1)(v) through (vi) of this 

section. The owner or operator of a kiln or inline kiln/raw 

mill subject to limitations on PM emissions that is equipped 

with a PM CEMS shall demonstrate initial compliance by 

conducting a performance test as specified in paragraph

(b)(1)(vii) of this section.

* * * * *

(ii) The owner or operator must install, calibrate, 

maintain and operate a permanent weigh scale system, or use 

another method approved by the Administrator, to measure and 

record weight rates in tons-mass per hour of the amount of 
193

clinker produced. The system of measuring hourly clinker 

production must be maintained within ±5 percent accuracy. The 

use of a system that directly measures kiln feed rate and uses a 

conversion factor to determine the clinker production rate is an 

acceptable method.

(iii) The emission rate, E, of PM (1b/ton of clinker) 

shall be computed for each run using equation 1 of this section:

 

PK 

C Q E  s sd (Eq. 3)

Where:

E = emission rate of particulate matter, kg/metric ton (lb/ton) 

of clinker production;

Cs = concentration of particulate matter, g/dscm (gr/dscf);

Qsd = volumetric flow rate of effluent gas, dscm/hr (dscf/hr);

P = total kiln clinker production rate, metric ton/hr (ton/hr); 

and

K = conversion factor, 1000 g/kg (7000 gr/lb).

(iv) Where there is an alkali bypass associated with a 

kiln or in-line kiln/raw mill, the main exhaust and alkali 

bypass of the kiln or in-line kiln/raw mill shall be tested 

simultaneously and the combined emission rate of particulate 

matter from the kiln or in-line raw mill and alkali bypass shall 

be computed for each run using equation 2 of this section:
194

 

PK 

C Q C Q

E

s k sdk sb sdb

c



 (Eq. 4)

Where:

Ec = combined emission rate of particulate matter from the kiln 

or in-line kiln/raw mill and bypass stack, kg/metric ton 

(lb/ton) of kiln clinker production;

Csk = concentration of particulate matter in the kiln or in-line 

kiln/raw mill effluent gas, g/dscm (gr/dscf);

Qsdk = volumetric flow rate of kiln or in-line kiln/raw mill 

effluent gas, dscm/hr (dscf/hr);

Csb = concentration of particulate matter in the alkali bypass 

gas, g/dscm (gr/dscf);

Qsdb = volumetric flow rate of alkali bypass effluent gas, 

dscm/hr (dscf/hr);

P = total kiln clinker production rate, metric ton/hr (ton/hr); 

and

K = conversion factor, 1000 g/kg (7000 gr/lb).

conversion factor, 1000 g/kg (7000 gr/lb).

* * * * *

(vii) The owner or operator of a kiln or in-line kiln/raw 

mill subject to limitations on emissions of PM that is equipped 

with a PM CEMS shall demonstrate initial compliance by operating 

the CEMS in accordance with Performance Specification 11 (40 CFR 

part 60, appendix B). The duration of the test shall be 3
195

hours. The owner or operator shall calculate the PM emission 

rate in kg/metric ton (lb/ton) of clinker using Equation 1 or 2

of this section. The owner or operator of an in-line kiln/raw 

mill shall conduct separate performance tests while the raw mill 

of the in-line kiln/raw mill is under normal operating 

conditions and while the raw mill of the in-line kiln/raw mill 

is not operating. The owner or operator shall continuously 

measure kiln feed rate, volumetric flow rate, and clinker 

production during the period of the test. 

* * * * *

(4)(i) The owner or operator of an affected source subject 

to limitations on emissions of THC shall demonstrate initial 

compliance with the THC limit by operating a continuous emission 

monitor in accordance with Performance Specification 8A (40 CFR 

part 60, appendix B). The duration of the performance test 

shall be 24 hours. The owner or operator shall calculate the

daily average THC concentration (as calculated from the oneminute averages) during the performance test. The owner or 

operator of an in-line kiln/raw mill shall demonstrate initial 

compliance by conducting separate performance tests while the 

raw mill of the in-line kiln/raw mill is under normal operating 

conditions and while the raw mill of the in-line kiln/raw mill 

is not operating.
196

(ii) As an alternative to complying with the THC limit, 

the owner or operator may comply with the limits for total 

organic HAP, as defined in §63.1341, by following the procedures 

in (b)(4)(ii) through (b)(4)(vi) of this section.

(iii) The owner or operator of a kiln complying with the 

alternative emissions limits for total organic HAP in §63.1343 

shall demonstrate initial compliance by conducting a performance 

test as specified in paragraphs (b)(4)(ii) through (b)(4)(vi) of 

this section. The owner or operator of an in-line kiln/raw mill 

complying with the emissions limits for total organic HAP in 

§63.1343 shall demonstrate initial compliance by conducting 

separate performance tests as specified in paragraphs (b)(4)(ii) 

through (b)(4)(vi) of this section while the raw mill of the inline kiln/raw mill is under normal operating conditions and 

while the raw mill of the in-line kiln/raw mill is not 

operating. 

(iv) Method 320 of appendix A to this part alone or in 

combination with method 18 of appendix A to part 60 of this 

chapter shall be used to determine emissions of total organic 

HAP. Each performance test shall consist of three separate runs 

under the conditions that exist when the affected source is 

operating at the representative performance conditions in 

accordance with §63.7(e). Each run shall be conducted for at 
197

least 1 hour. The average of the three runs shall be used to 

determine initial compliance.

(v) At the same time that the owner or operator is 

determining compliance with the emissions limits for total 

organic HAP, the owner or operator shall also determine THC 

emissions by operating a continuous emission monitor in 

accordance with Performance Specification 8A of appendix B to 

part 60 of this chapter. The duration of the test shall be three

hours, and the average THC concentration (as calculated from the 

one-minute averages) during the three-hour test shall be 

calculated. The THC concentration measured during the initial 

performance test for total organic HAP will be used to monitor 

compliance subsequent to the initial performance test.

(vi) Emissions tests to determine compliance with total 

inorganic HAP limits shall be repeated annually, beginning one

year from the date of the initial performance tests.

(5) The owner or operator of a kiln or in-line kiln/raw 

mill subject to an emission limitation for mercury in §63.1343 

shall demonstrate initial compliance with the mercury limit by

complying with the requirements of (b)(5)(i) through (b)(5)(vi) 

of this section.

(i) Operate a continuous emission monitor in accordance 

with Performance Specification 12A (40 CFR part 60, appendix B). 

The duration of the performance test shall be a calendar month. 
198

For each calendar month in which the kiln or in-line kiln/raw 

mill operates, hourly Hg concentration data, stack gas 

volumetric flow rate data shall be obtained. The owner or 

operator of an in-line kiln/raw mill shall demonstrate initial 

compliance by operating a continuous emission monitor while the 

raw mill of the in-line kiln/raw mill is under normal operating 

conditions and while the raw mill of the in-line kiln/raw mill 

is not operating.

(ii) Owners or operators using a mercury CEMS must 

install, operate, calibrate, and maintain an instrument for 

continuously measuring and recording the exhaust gas flow rate 

to the atmosphere according to the requirements in §60.63(m) of 

this chapter.

(iii) The owner or operator shall determine compliance 

with the Hg limitations by dividing the average Hg concentration 

by the clinker production rate during the same calendar month 

using the Equation 3 of this section:

 

PK 

C Q E  s sd (Eq. 5)

Where:

E = emission rate of mercury, kg/metric ton (lb/million tons) of 

clinker production;

Cs = concentration of mercury, g/dscm (g/dscf);
199

Qsd = volumetric flow rate of effluent gas, dscm/hr (dscf/hr);

P = total kiln clinker production rate, metric ton/hr (million 

ton/hr); and

K = conversion factor, 1000 g/kg (454 g/lb).

(6) The owner or operator of an affected source subject 

to limitations on emissions of HCl shall demonstrate initial 

compliance with the HCl limit by one of the following methods:

(i) If your source is equipped with a wet scrubber such 

as a spray tower, packed bed, or tray tower, use Method 321 of 

appendix A to this part. A repeat test must be performed every 5 

years to demonstrate continued compliance.

(ii) If your source is not controlled by a wet scrubber, 

you must operate a continuous emission monitor in accordance 

with Performance Specification 15 of appendix B of part 60. The 

duration of the performance test shall be 24 hours. The owner 

or operator shall calculate the daily average HCl concentration 

(as calculated from the one-minute averages) during the

performance test. The owner or operator of an in-line kiln/raw 

mill shall demonstrate initial compliance by conducting separate 

performance tests while the raw mill of the in-line kiln/raw 

mill is under normal operating conditions and while the raw mill 

of the in-line kiln/raw mill is not operating.

(c) Except as provided in paragraph (e) of this section, 

performance tests are required for existing kilns or in-line 
200

kiln/raw mills that are subject to a PM, THC, HCl or mercury 

emissions limit and must be repeated every 5 years except for 

pollutants where that specific pollutant is monitored using a 

CEMS.

* * * * * 

(f) The owner or operator of an affected facility shall

submit the information specified in paragraphs (c)(1) through 

(c)(4) of this section no later than 60 days following the 

initial performance test. All reports shall be signed by the 

facilities manager.

(1) The initial performance test data as recorded under 

§60.56c(b)(1) through (b)(14), as applicable. 

(2) The values for the site-specific operating parameters 

established pursuant to §60.56c(d), (h), or (j), as applicable, 

and a description, including sample calculations, of how the 

operating parameters were established during the initial 

performance test.

(3) For each affected facility as defined in 

§60.50c(a)(3).

(4) That uses a bag leak detection system, analysis and 

supporting documentation demonstrating conformance with EPA 

guidance and specifications for bag leak detection systems in 

§60.57c(h).
201

(g) For affected facilities, as defined in §60.50c(a)(3) 

and (4), that choose to submit an electronic copy of stack test 

reports to EPA’s WebFIRE data base, as of December 31, 2011, the 

owner or operator of an affected facility shall enter the test 

data into EPA’s data base using the Electronic Reporting Tool 

located at http://www.epa.gov/ttn/chief/ert/ert_tool.html.

9. Section 63.1350 is amended:

a. By revising paragraph (g) introductory text;

b. By revising paragraph (h) introductory text;

c. By revising paragraph (h)(2) through (h)(4);

d. By revising paragraph (k);

b. By revising paragraphs (m) introductory text;

e. By revising paragraph (n),(o) and (p); and

c. By adding new paragraph (q) and (r) to read as follows:

§63.1350 Monitoring requirements.

* * * * *

(g) The owner or operator of an affected source subject to 

an emissions limitation on D/F emissions that employs carbon 

injection as an emission control technique shall comply with the 

monitoring requirements of paragraphs (f)(1) through (f)(6) and 

(g)(1) through (g)(6) of this section to demonstrate continuous 

compliance with the D/F emissions standard.

* * * * *
202

(h) The owner or operator of an affected source subject to 

a limitation on THC emissions under this subpart shall comply 

with the monitoring requirements of paragraphs (h)(1) through 

(h)(3) of this section to demonstrate continuous compliance with 

the THC emission standard:

* * * * *

(2) For existing facilities complying with the THC 

emissions limits of §63.1343, the 30 day average THC 

concentration in any gas discharged from the main exhaust of a 

kiln, or in-line kiln/raw mill, must not exceed their THC 

emissions limit, reported as propane, corrected to seven percent 

oxygen.

(3) For new or reconstructed facilities complying with the 

THC emission limits of §63.1343, the 30 day average THC 

concentration in any gas discharged from the main exhaust of a 

kiln or in-line kiln/raw mill must not exceed their THC emission 

limit, reported as propane, corrected to seven percent oxygen.

(4) For new or reconstructed facilities complying with the 

THC emission limits of §63.1346, any daily average THC 

concentration in any gas discharged from a raw material dryer

must not exceed their THC emission limit, reported as propane, 

corrected to seven percent oxygen. 

* * * * *
203

(k) The owner or operator of an affected source subject to 

a particulate matter standard under §63.1343 using a fabric 

filter for PM control must install, operate, and maintain a bag 

leak detection system according to paragraphs (k)(1) through 

(k)(3) of this section. 

(1) Each bag leak detection system must meet the 

specifications and requirements in paragraphs (k)(1)(i) through 

(k)(1)(viii) of this section. 

(i) The bag leak detection system must be certified by the 

manufacturer to be capable of detecting PM emissions at 

concentrations of 1 milligram per dry standard cubic meter 

(0.00044 grains per actual cubic foot) or less.

(ii) The bag leak detection system sensor must provide 

output of relative PM loadings. The owner or operator shall 

continuously record the output from the bag leak detection 

system using electronic or other means (e.g., using a strip 

chart recorder or a data logger).

(iii) The bag leak detection system must be equipped with 

an alarm system that will sound when the system detects an 

increase in relative particulate loading over the alarm set 

point established according to paragraph (k)(1)(iv) of this 

section, and the alarm must be located such that it can be heard 

by the appropriate plant personnel.
204

(iv) In the initial adjustment of the bag leak detection 

system, you must establish, at a minimum, the baseline output by 

adjusting the sensitivity (range) and the averaging period of 

the device, the alarm set points, and the alarm delay time.

(v) Following initial adjustment, you shall not adjust the 

averaging period, alarm set point, or alarm delay time without 

approval from the Administrator or delegated authority except as 

provided in paragraph (k)(1)(vi) of this section.

(vi) Once per quarter, you may adjust the sensitivity of 

the bag leak detection system to account for seasonal effects, 

including temperature and humidity, according to the procedures 

identified in the site-specific monitoring plan required by 

paragraph (k)(2) of this section.

(vii) You must install the bag leak detection sensor 

downstream of the fabric filter.

(viii) Where multiple detectors are required, the system’s 

instrumentation and alarm may be shared among detectors.

(2) You must develop and submit to the Administrator or 

delegated authority for approval a site-specific monitoring plan 

for each bag leak detection system. You must operate and 

maintain the bag leak detection system according to the sitespecific monitoring plan at all times. Each monitoring plan 

must describe the items in paragraphs (k)(2)(i) through 
205

(k)(2)(vi) of this section. At a minimum you must retain records 

related to the site-specific monitoring plan and information 

discussed in paragraphs (k)(2)(i) through (k)(2)(vi) of this 

section for a period of 2 years on-site and 3 years off-site;

(i) Installation of the bag leak detection system;

(ii) Initial and periodic adjustment of the bag leak 

detection system, including how the alarm set-point will be 

established;

(iii) Operation of the bag leak detection system, 

including quality assurance procedures;

(iv) How the bag leak detection system will be maintained, 

including a routine maintenance schedule and spare parts 

inventory list;

(v) How the bag leak detection system output will be 

recorded and stored; and

(vi) Corrective action procedures as specified in

paragraph (k)(3) of this section. In approving the sitespecific monitoring plan, the Administrator or delegated 

authority may allow owners and operators more than 3 hours to 

alleviate a specific condition that causes an alarm if the owner 

or operator identifies in the monitoring plan this specific 

condition as one that could lead to an alarm, adequately 

explains why it is not feasible to alleviate this condition 
206

within 3 hours of the time the alarm occurs, and demonstrates 

that the requested time will ensure alleviation of this 

condition as expeditiously as practicable.

(3) For each bag leak detection system, you must initiate 

procedures to determine the cause of every alarm within 1 hour 

of the alarm. Except as provided in paragraph (k)(2)(vi) of 

this section, you must alleviate the cause of the alarm within 3 

hours of the alarm by taking whatever corrective action(s) are 

necessary. Corrective actions may include, but are not limited 

to the following:

(i) Inspecting the fabric filter for air leaks, torn or 

broken bags or filter media, or any other condition that may 

cause an increase in PM emissions;

(ii) Sealing off defective bags or filter media;

(iii) Replacing defective bags or filter media or 

otherwise repairing the control device;

(iv) Sealing off a defective fabric filter compartment;

(v) Cleaning the bag leak detection system probe or 

otherwise repairing the bag leak detection system; or

(vi) Shutting down the process producing the PM emissions.

(4) The owner or operator of a kiln or clinker cooler 

using a PM continuous emission monitoring system (CEMS) to 
207

demonstrate compliance with the particulate matter emission 

limit in §63.1343 must install, certify, operate, and maintain 

the CEMS as specified in paragraphs (p)(1) through (p)(3) of 

this section.

* * * * *

(m) The requirements under paragraph (e) of this section 

to conduct daily Method 22 testing shall not apply to any 

specific raw mill or finish mill equipped with a continuous 

opacity monitor system (COMS) or bag leak detection system 

(BLDS). If the owner or operator chooses to install a COM in 

lieu of conducting the daily visual emissions testing required 

under paragraph (e) of this section, then the COM must be 

installed at the outlet of the PM control device of the raw mill 

or finish mill, and the COM must be installed, maintained, 

calibrated, and operated as required by the general provisions 

in subpart A of this part and according to PS-1 of appendix B to 

part 60 of this chapter. The 6-miunute average opacity for any 

6-minute block period must not exceed 10 percent. If the owner 

or operator chooses to install a BLDS in lieu of conducting the 

daily visual emissions testing required under paragraph (e) of 

this section, the requirements in paragraphs (k)(1) 

through(k)(3) of this section apply to each BLDS.

* * * * *
208

(n) The owner or operator of a kiln or in-line kiln raw 

mill shall install a CEMS to continuously measure mercury

emission rates in accordance with Performance Specification 12A

(40 CFR part 60, appendix B). The owner or operator shall 

operate and maintain each CEMS according to the quality 

assurance requirements in Procedure 1 of 40 CFR part 60, 

appendix F.

(o) The owner or operator of any portland cement plant 

subject to the PM limit (lb/ton of clinker) for new or existing 

area sources in §63.1343(d) or (e) shall:

(1) Install, calibrate, maintain and operate a permanent 

weigh scale system, or use another method approved by the 

Administrator, to measure and record weight rates in tons-mass 

per hour of the amount of clinker produced. The system of 

measuring hourly clinker production must be maintained within ±5 

percent accuracy. The use of a system that directly measures 

kiln feed rate and uses a conversion factor to determine the 

clinker production rate is an acceptable method.

(2) Record the daily clinker production rates and kiln 

feed rates.

(p) The owner or operator of a kiln or clinker cooler using 

a PM continuous emission monitoring system (CEMS) to demonstrate 

compliance with the particulate matter emission limit in 

§63.1343 must install, certify, operate, and maintain the CEMS 
209

as specified in paragraphs (p)(1) through (p)(3) of this 

section.

(1) The owner or operator must conduct a performance 

evaluation of the PM CEMS according to the applicable 

requirements of §60.13, Performance Specification 11 of appendix

B of part 60, and Procedure 2 of appendix F to part 60.

(2) During each relative accuracy test run of the CEMS 

required by Performance Specification 11 of appendix B to part 

60, PM and oxygen (or carbon dioxide) data must be collected 

concurrently (or within a 30-to 60-minute period) during 

operation of the CEMS and when conducting performance tests 

using the following test methods:

(i) For PM, Method 5 or 5B of appendix A-5 to part 60 or 

Method 17 of appendix A-6 to part 60.

(ii) For oxygen (or carbon dioxide), Method 3, 3A, or 3B 

of appendix A-2 to part 60, as applicable.

(3) Procedure 2 of appendix F to part 60 for quarterly 

accuracy determinations and daily calibration drift tests. The 

owner or operator must perform Relative Response Audits annually 

and Response Correlation Audits every 3 years.

(q) The owner or operator of an affected source subject to 

limitations on emissions of HCl shall:
210

(i) Continuously monitor compliance with the HCl limit by 

operating a continuous emission monitor in accordance with 

Performance Specification 15 of part 60, appendix B. The owner 

or operator shall operate and maintain each CEMS according to 

the quality assurance requirements in Procedure 1 of 40 CFR part 

60, appendix F, or

(ii) Monitor your wet scrubber parameters as specified in 

40 CFR part 63 subpart SS.

(r) The owner or operator complying with the total 

organic HAP emissions limits of §63.1343 shall continuously 

monitor THC according to paragraphs (r)(1) through (r)(3) of 

this section to demonstrate continuous compliance with the 

emission limits for total organic HAP.

(1) Install, operate and maintain a THC continuous emission 

monitoring system in accordance with Performance Specification 

8A, of appendix B to part 60 of this chapter and comply with all 

of the requirements for continuous monitoring found in the 

general provisions, subpart A of the part.

(2) Calculate the three-hour average THC concentration as 

the average of 180 successive one-minute average THC readings. 

The three-hour average THC concentration shall not exceed the 

average THC concentration established during the initial 

performance tests for total organic HAP. 
211

10. Section 63.1351 is amended by revising paragraph (d) 

and adding paragraphs (e) and (f) to read as follows:

§63.1351 Compliance dates.

* * * * *

(d) The compliance date for a new source which commenced 

construction after December 2, 2005, and before December 20, 

2006 to meet the THC emission limit of 6 ppmvd or the mercury 

standard of 14 lb/MM tons clinker will be December 21, 2009, or 

the effective date of these amendments, whichever is later.

(e) The compliance data for existing sources with the 

revised PM, mercury, THC, and HCl emissions limits will be 3

years from the effective data of these amendments.

(f) The compliance date for new sources not subject to 

paragraph (d) of this section will be the effective date of the 

final rule or startup, whichever is later.

11. Section 63.1354 is amended by adding paragraph 

(b)(9)(vi) to read as follows:

§63.1354 Reporting requirements.

* * * * *

(b )* * *

(9) * * *

(vi) Monthly rolling average mercury concentration for 

each kiln and in-line kiln/raw mill. 

* * * * *
212

12. Section 63.1355 is amended by revising paragraph (e) 

to read as follows:

§63.1355 Recordkeeping requirements.

* * * * *

(e) You must keep records of the daily clinker production 

rates and kiln feed rates for area sources. 

* * * * *

13. Section 63.1356 is revised to read as follows: 

§63.1356 Sources with multiple emission limits or monitoring 

requirements. 

If an affected facility subject to this subpart has a 

different emission limit or requirement for the same pollutant 

under another regulation in title 40 of this chapter, the owner 

or operator of the affected facility must comply with the most 

stringent emission limit or requirement and is exempt from the 

less stringent requirement. 

14. Table 1 to Subpart LLL of Part 63 is revised to read 

as follows:

Table 1 to Subpart LLL of Part 63—Applicability of General 

Provisions

Citation Requirement

Applies 

to 

Subpart 

LLL Comment

63.1(a)(1)–(4) Applicability Yes
213

63.1(a)(5) No [Reserved]

63.1(a)(6)–(8) Applicability Yes

63.1(a)(9) No [Reserved]

63.1(a)(10)–(14) Applicability Yes

63.1(b)(1) Initial Applicability 

Determination

No §63.1340 

specifies 

applicability.

63.1(b)(2)–(3) Initial Applicability 

Determination

Yes

63.1(c)(1) Applicability After 

Standard Established

Yes

63.1(c)(2) Permit Requirements Yes Area sources 

must obtain 

Title V 

permits.

63.1(c)(3) No [Reserved]

63.1(c)(4)–(5) Extensions, Notifications Yes

63.1(d) No [Reserved]

63.1(e) Applicability of Permit 

Program

Yes

63.2 Definitions Yes Additional 

definitions in 

§63.1341.

63.3(a)–(c) Units and Abbreviations Yes

63.4(a)(1)–(3) Prohibited Activities Yes

63.4(a)(4) No [Reserved]

63.4(a)(5) Compliance date Yes

63.4(b)–(c) Circumvention, SeverabilityYes

63.5(a)(1)–(2) Construction/ReconstructionYes

63.5(b)(1) Compliance Dates Yes

63.5(b)(2) No [Reserved]

63.5(b)(3)–(6) Construction Approval, 

Applicability

Yes

63.5(c) No [Reserved]
214

63.5(d)(1)–(4) Approval of 

Construction/Reconstruction

Yes

63.5(e) Approval of 

Construction/Reconstruction

Yes

63.5(f)(1)–(2) Approval of 

Construction/Reconstruction

Yes

63.6(a) Compliance for Standards 

and Maintenance

Yes

63.6(b)(1)–(5) Compliance Dates Yes

63.6(b)(6) No [Reserved]

63.6(b)(7) Compliance Dates Yes

63.6(c)(1)–(2) Compliance Dates Yes

63.6(c)(3)–(4) No [Reserved]

63.6(c)(5) Compliance Dates Yes

63.6(d) No [Reserved]

63.6(e)(1)–(2) Operation & Maintenance Yes

63.6(e)(3) Startup, Shutdown 

Malfunction Plan

Yes

63.6(f)(1)–(3) Compliance with Emission 

Standards

Yes

63.6(g)(1)–(3) Alternative Standard Yes

63.6(h)(1)–(2) Opacity/VE Standards Yes

63.6(h)(3) No d]

63.6(h)(4)–(h)(5)(i)Opacity/VE Standards Yes

63.6(h)(5)(ii)–(iv) Opacity/VE Standards No Test duration 

specified in 

subpart LLL.

63.6(h)(6) Opacity/VE Standards Yes

63.6(h)(7) Opacity/VE Standards Yes

63.6(i)(1)–(14) Extension of Compliance Yes

63.6(i)(15) No [Reserved]

63.6(i)(16) Extension of Compliance Yes

63.6(j) Exemption from Compliance Yes
215

63.7(a)(1)–(3) Performance Testing 

Requirements

Yes §63.1349 has 

specific 

requirements.

63.7(b) Notification Yes

63.7(c) Quality Assurance/Test PlanYes

63.7(d) Testing Facilities Yes

63.7(e)(1)–(4) Conduct of Tests Yes

63.7(f) Alternative Test Method Yes

63.7(g) Data Analysis Yes

63.7(h) Waiver of Tests Yes

63.8(a)(1) Monitoring Requirements Yes

63.8(a)(2) Monitoring No §63.1350 

includes CEMS 

requirements.

63.8(a)(3) No [Reserved]

63.8(a)(4) Monitoring No Flares not 

applicable.

63.8(b)(1)–(3) Conduct of Monitoring Yes

63.8(c)(1)–(8) CMS Operation/Maintenance Yes Temperature 

and activated 

carbon 

injection 

monitoring 

data reduction 

requirements 

given in 

subpart LLL.

63.8(d) Quality Control Yes

63.8(e) Performance Evaluation for 

CMS

Yes Performance 

specification 

supersedes 

requirements 

for THC CEMS.

63.8(f)(1)–(5) Alternative Monitoring 

Method

Yes Additional 

requirements 

in 

§63.1350(l).
216

63.8(f)(6) Alternative to RATA Test Yes

63.8(g) Data Reduction Yes

63.9(a) Notification Requirements Yes

63.9(b)(1)–(5) Initial Notifications Yes

63.9(c) Request for Compliance 

Extension

Yes

63.9(d) New Source Notification for 

Special Compliance 

Requirements

Yes

63.9(e) Notification of Performance 

Test

Yes

63.9(f) Notification of VE/Opacity 

Test

Yes Notification 

not required 

for VE/opacity 

test under 

§63.1350(e) 

and (j).

63.9(g) Additional CMS 

Notifications

Yes

63.9(h)(1)–(3) Notification of Compliance 

Status

Yes

63.9(h)(4) No [Reserved]

63.9(h)(5)–(6) Notification of Compliance 

Status

Yes

63.9(i) Adjustment of Deadlines Yes

63.9(j) Change in Previous 

Information

Yes

63.10(a) Recordkeeping/Reporting Yes

63.10(b) General Requirements Yes

63.10(c)(1) Additional CMS 

Recordkeeping

Yes PS–8A 

supersedes 

requirements 

for THC CEMS.

63.10(c)(2)–(4) No [Reserved]

63.10(c)(5)–(8) Additional CMS 

Recordkeeping

Yes PS–8A 

supersedes 

requirements 
217

for THC CEMS.

63.10(c)(9) No [Reserved]

63.10(c)(10)–(15) Additional CMS 

Recordkeeping

Yes PS–8A 

supersedes 

requirements 

for THC CEMS.

63.10(d)(1) General Reporting 

Requirements

Yes

63.10(d)(2) Performance Test Results Yes

63.10(d)(3) Opacity or VE Observations Yes

63.10(d)(4) Progress Reports Yes

63.10(d)(5) Startup, Shutdown, 

Malfunction Reports

Yes

63.10(e)(1)–(2) Additional CMS Reports Yes

63.10(e)(3) Excess Emissions and CMS 

Performance Reports

Yes Exceedances 

are defined in 

subpart LLL.

63.10(f) Waiver for 

Recordkeeping/Reporting

Yes

63.11(a)–(b) Control Device RequirementsNo Flares not 

applicable.

63.12(a)–(c) State Authority and 

Delegations

Yes

63.13(a)–(c) State/Regional Addresses Yes

63.14(a)–(b) Incorporation by Reference Yes

63.15(a)–(b) Availability of InformationYes