UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 1595 Wynkoop Street DENVER, CO 80202-1129 Phone 800-227-8917 http://www.epa.gov/region08 

# SEP - 92011
Ref: 8P-AR
CERTIFIED MAIL

- RETURN RECEIPT REQUESTED

Thomas Wood Stoel Rives, LLP 900 S.W. Fifth Avenue Suite 2600 Portland, Oregon 97204
RE: Request for Additional Information for the Best Available Retrofit Technology Determination for Ash Grove Cement, Pursuant to Section 114(a) ofthe Clean Air Act (42 U.S.C. Section 7414(a))

DearMr. Wood:
Thank you for your letter dated July 18,20II,regarding additional information that was requested for the Best Available RetrofitTechnology (BART) determination for Ash Grove Cement. Itis necessary for us to respond to that letterto explain our interpretation ofthe issues that you raised.

On the second page ofyour letter, you suggestthat you believe there is the potential that BART will not apply to the MontanaCity plant because ofsettlement negotiations with the Office ofEnforcement and Compliance Assurance that may result in the installation ofpollution controls that you suggest will equate to Best Available Control Technology (BACT). First, we have discussed this matter with the OECA staffinvolved in the negotiations you reference. The OECA has been clearwith us that they do not intend to negotiate any provisions that supersede or displace the BARTprocess. Also, to the extent you intendedto suggest that the OECAhas determined that wet scrubbers at MontanaCity are not technically feasible, the OECA has clarified that they have not made this determination. Whatever compromise is reached on settlement negotiations with the OECA is not determinative ofBART. The requirements under BART are not necessarily commensurate with BACT. Therefore, based onthe requirements ofthe Regional Haze Rule, we are proceeding with ourrequired BART analysis.
Also in your letter, you suggest that Ash Grove believes that wet scrubbers are no longertechnically feasible because no wet scrubber manufacturer with experience in the cement industry will guarantee that theirunit can meetthe new Subpart LLL Particulate Matter (PM) standard. At this time, we are evaluating howwet scrubbing technology shouldbe considered in the Regional Haze Rule BART requirements. Ifwe determine that wet scrubbing is infeasible underthe Regional Haze Rule, then other available technologies, such as dry scrubbing techniques, will be evaluated. You must support your statements that wet scrubbing may not be technically feasible and submit a five factor analysis ofdry scrubbing techniques. This information is necessary to complete the Regional Haze FederalImplementation Plan (FIP) for Montanaand we are requesting that you send that information by September 30, 20II.

Pursuant to Section 114 ofthe Clean AirAct, 42 V.S.c. §7414, and under authority duly delegated to the undersigned, you are required to provide us with the information specified in this letter. This information will be used by the EPA in developing a Regional Haze FIP, orin the event MDEQ resumes development ofa Regional Haze State Implementation Plan (SIP), in assisting MDEQ in that effort and/orreviewing a Regional Haze SIP for Montana. Furthermore, information requests pursuantto Section 114 ofthe CAA are not limited to sources that are regulated by the particular rule the EPA is implementing. For example, Section 114(a)(l) says that the EPA may gather information from "any person who owns oroperates any emission source"or "whothe Administratorbelieves may have information necessary for the purposes set forth in this subsection."

A duly authorized officer or agent ofthe facility must certify as true, accurate, and completethe response to this information by signing the enclosed Statement ofCertification and returning it with the response. Such officeroragent must have sufficientknowledge and authority to make such representations on behalfofPPL Montana, LLC.
Please submit yourresponse to:
U.S. Environmental Protection Agency Region VIII 1595 Wynkoop Street Denver, CO 80202-1129 Attention: Vanessa Hinkle, 8P-AR

Pursuant to Section 114(c) ofthe CAA, 42 V.S.c. §7414(c), and 40 C.F.R. Part 2, Subpart B, Ash Grove Cement is entitled to assert a business confidentiality claim covering any part ofthe submitted information. The enclosure specifies the assertion and substantiationrequirements for business confidentiality claims. Your substantiation must be included with your response at the time the information is submitted and we will begin making ourdetermination immediately upon receipt ofthe information you submit including your assertion and substantiation. Failure to assert such a claim makes the submitted information subject to publicdisclosure upon request and without further notice to you, pursuant to the Freedom ofInformation Act, 5 U.S.c. Section 552. Information subjectto a business confidentiality claim may only be made available to the public in accordance with 40 C.F.R. Part 2, Subpart B.

A knowing submittal offalse information in response to this request may be actionable under Section I13(c)(2) ofthe CAA, as well as 18 V.S.c. §§1001 and 1341. Failure to comply withthe terms ofthis request may subject Ash Grove Cementto enforcementaction under Section 113 ofthe CAA. 42 U.S.c. §7413.
The requirements ofthis letterare not subjectto the PaperworkReduction Act of 1980,44V.S.c. §3501 el seq.We appreciate your cooperation in this matter. Ifyouhave any questions please call VanessaHinkle of my staffat 303-312-6561. Sincerely,

Stephen S. Tuber Assistant Regional Administrator Office ofPartnerships and Regulatory Assistance
Enclosure

cc: John Bunyak, NPS Sandra Silva, USFWS Thomas Dzomba, USFS