Dave Freudenthal, Governor 

Department of Environmental Quality 

To protect, conserve and enhance the quality of Wyoming's 

environment for the benefit of current and future generations. 

Y " 

May 3, 2007 

Mr. Robbie Roberts 

Regional Administrator 

US EPA Region 8 

1595 Wynkoop Street 

Denver, CO 80202-1129 

John Corra, Director 

RE : State Implementation Plan (SIP) Approval Request Per Section 110(a)(2)(D)(i) of 

the Clean Air Act (Wyoming Interstate Transport SIP) 

Dear Mr. Roberts : 

The State of Wyoming is submitting a revision to our State Implementation Plan (SIP) to 

address requirements under section 110(a)(2)(D)(i) of the Clean Air Act. Using guidance 

provided by EPA in 2006, the State of Wyoming has made a negative declaration with regard to 

impact on other states, demonstrating the following: 

Y Wyoming does not contribute to nonattainment or interfere with maintenance of the 

ozone or PMZ.5 standards in other states . 

Y Wyoming's PSD (Prevention of Significant Deterioration) Rule ensures that Wyoming 

does not interfere with PSD implementation in other states . 

Y Wyoming sources of emissions do not interfere with implementation of RAVI 

(Reasonably Attributable Visibility Impairment) in other states . 

>= Since states are not required to submit Regional Haze SIPs until December 2007, it is too 

early to assess the impact of transported pollution on visibility in federally protected 

areas . 

The above demonstration was made via a public process before the Wyoming Air Quality 

Advisory Board in Casper, Wyoming on December 11, 2006, where the revised SIP was 

recommended for adoption. " 

The revised SIP was forwarded to the Governor on April 9, 2007 and approved on April 

15, 2007 . 

Since all of the necessary State reviews and approvals have been secured, I am 

submitting two copies of the revised State Implementation Plan . 

Herschler Building " 122 West 25th Street " Cheyenne, WY 82002 " http ://deq .state .wy.us 

ADMIN/OUTREACH ABANDONED MINES AIR QUALITY INDUSTRIAL SITING LAND QUALITY SOLID & HAZ. WASTE WATER QUALITY 

(307) 777-7758 (307) 777-6145 (307) 777-7391 (307) 777-7369 (307) 777-7756 (307) 777-7752 (307) 777-7781 

FAX 777-3610 FAX 777-6462 FAX 777-5616 FAX 777-6937 FAX 777-5864 FAX 777-5973 FAX 777-5973 
Mr. Robbie Roberts 

May 3, 2007 

Page 2 of 2 

The following administrative materials are included in the plan submission and have been 

attached for your review: 

1 . A copy of the Certification Page for State Implementation Plans for the Air Quality 

Division of the Department of Environmental Quality, indicating April 15, 2007 as the 

approval date of the SIP revision . 

2. An April 9, 2007 memorandum from John Corra, Director of the Department of 

Environmental Quality, to the Governor recommending approval of the revised SIP, in 

order that the revised SIP can be submitted to EPA. 

3 . An April 24, 2007 letter from Nancy Vehr, Senior Assistant Attorney General, 

documenting the necessary legal authority under State law to adopt and implement the 

revised SIP . 

4 . A copy of the notice issued by the Air Quality Division for the public meeting with a list 

of newspapers and dates of publication. 

5 . A list of signatures of witnesses present at the December 11, 2006 meeting as well as a 

copy of the agenda. 

6. A copy of the revised Wyoming Interstate Transport SIP. 

With this submission I am asking for Environmental Protection Agency approval of the 

revised Wyoming Interstate Transport SIP for the State of Wyoming as approved by the 

Governor on April 15, 2007 . 

If you have any questions regarding this submittal, please feel free to contact David A. 

Finley, Air Quality Administrator, at 307-777-7391 . 

Sincerely, 

V. Corra 

irector 

Department of Environmental Quality 

Enclosures 

cc: David A. Finley, Administrator, Air Quality Division w/enc . 

Christine Anderson, Air Quality Division w/enc. 

Domenico Mastrangelo, EPA w/enc. 
CERTIFICATION PAGE FOR STATE IMPLEMENTATION PLANS FOR THE 

AIR QUALITY DIVISION OF THE DEPARTMENT OF ENVIRONMENTAL QUALITY 

I, John V. Corra, do hereby certify that I am the administrative head of the Department of 

Environmental Quality (DEQ . I have attached a copy of the State Implementation Plan (SIP) 

pertaining to Interstate Transport. 

In accordance with W.S . 9-1-208, 35-11-102, -109, -110, and the Governor's delegation of 

authority for SIP submittals dated April 4, 2003, the DEQ Director has the authority to develop 

and submit SIPs reviewed and approved by the Governor. - 

This SIP was developed to comply with requirements of the Clean Air Act 110(a)(2)(D)(i) for 

the 8-hour ozone and PMZ.5 NAAQS promulgated in July 1997. 

The Public Hearing Notice of a change in the SIP was provided through paid advertisement in 

the following newspapers Casper Star Tribune - November 10, 2006, Gillette News-Record -

November 10, 2006, Wyoming Tribune Eagle - November 11, 2006, Rock Springs Daily Rocket 

Miner - November 11, 2006, which were published at least 30 days prior to the date of the public 

hearing. Notice was also provided through a general mailing to 199 interested parties, including 

the Regional EPA Administrator and a continuous posting on the Air Quality Division website at 

http://deg .state .wy.us/aqd/index.asp?paQeid=8. A copy of the Public Hearing Notice is attached 

hereto as Appendix A. 

The proposed SIP was made available for public inspection at The Department of Environmental 

Quality, Herschler Building, 2"d Floor, 122 W. 25th Street, Cheyenne, Wyoming, 82002, as well 

as through the Air Quality Division website: 

The Air Quality Division held a public hearing on this SIP before the Air Quality Advisory 

Board on December 11, 2006 at the Casper DEQ Field Office, 152 N. Durbin, Suite 100, Casper, 

Wyoming. 

The Air Quality Advisory Board recommended adoption of this SIP on December 11, 2006. 

Procedures described above satisfy the requirements for public hearings under 40 CFR 51 .102 

for preparing SIPs. 

The DEQ hereby adopts this SIP on J-1S- c,7 

Direct 

GOVERNOR'S STATEMENT 

, Department of Environmental Quality 

I have reviewed and approved DEQ's adoption of this SIP . 

5 ate W Approved ` 
Dave Freudenthal, Governor 

Department of Environmental Quality 

To protect, conserve and enhance the quality of Wyoming's 

environment for the benefit of current and future generations. 

To : Governor Freudenthal 

John Corra, Director 

From: John V. Corra, Director, Department of Environmental Quality (DEQ) (The agency cor~t ct rson 

is Christine Anderson, 307-673-9337, tander(r).state .wy.us /~) 

Subject: Revision to the State Implementation Plan (SIP) Required Under Section 110(a)(2)(D)(i) of the 

Clean Air Act 

Date: April 9, 2007 

Priority : Normal 

Summary: The State of Wyoming is submitting a revision to the State Implementation Plan (SIP) to address 

requirements under section 110(a)(2)(D)(i) of the Clean Air Act. This portion of the Clean Air 

Act requires states to address emissions that could affect other states through interstate transport. 

EPA issued guidance to states on how to prepare SIPs to satisfy these requirements in August and 

September of 2006. Using this guidance, the State has made a negative declaration with regard to 

impact on other states, demonstrating the following: 

Wyoming does not contribute to nonattainment or interfere with maintenance of the ozone or 

PM,.5 standards in other states . 

Wyoming's PSD (Prevention of Significant Deterioration) Rule ensures that Wyoming does 

not interfere with PSD implementation in other states . 

Wyoming sources of emissions do not interfere with implementation of RAVI (Reasonably 

Attributable Visibility Impairment) in other states . 

Since states are not required to submit Regional Haze SIPs until December 2007, it is too 

early to assess the impact of transported pollution on visibility in federally protected areas. 

This demonstration was made through a public process before the Air Quality Advisory Board in 

Casper, Wyoming on December 11, 2006 . Documentation of the public process has been 

provided in the attached "Certification Page for State Implementation Plans for the Air Quality 

Division of the Department of Environmental Quality" . 

The Environmental Protection Agency (EPA) must approve or deny these revisions to the SIP by 

May 25, 2007. The Department is reconunending that you sign the attached certification page, so 

that the SIP revisions can be submitted to EPA and approved in lieu of a Federal Implementation 

Plan. 

Governor's Response Options: 

Sign the attached certification page and return to David A. Finley, Administrator, Air 

Quality Division, 2"d Floor Herschler Building. 

Delay submittal and schedule a meeting with 

Governor's Staff Representative 

cc : David A. Finley, AQD 

Nancy Vehr, AG 

Christine Anderson . AQD 

Herschler Building " 122 West 25th Street " Cheyenne, WY 82002 " http ://deq .state .wy.us 

ADMIN/OUTREACH ABANDONED MINES AIR QUALITY INDUSTRIAL SITING LAND QUALITY SOLID & HAZ. WASTE WATER QUALITY 

(307) 777-7758 (307) 777-6145 (307) 777-7391 (307) 777-7369 (307) 777-7756 (307) 777-7752 (307) 777-7781 

FAX 777-3610 FAX 777-6462 FAX 777-5616 FAX 777-6937 FAX 777-5864 FAX 777-5973 FAX 777-5973 
Office of the Attorney General 

Governor Water and Natural Resources Division Chief Deputy Attorney General 

Dave Freudenthal 123 State Capitol Elizabeth C. Gagen 

Cheyenne, Wyoming 82002 

Attomey General (307) 777-6946 Telephone Deputy Attorney General 

Patrick J. Crank (307) 777-3542 Fax Jay A. Jerde 

PRIVII.EGED AND CONFIDENTIAL 

April 24, 2007 

Dave Finley, Administrator 

Air Quality Division 

Dept. of Environmental Quality 

122 West 25th Street 

Cheyenne, WY 82002 

RE: Legal Authority to Adopt and Implement Amendments to Wyoming's State 

Implementation Plan Addressing Requirements Under Section 

110(a)(2)(D)(i) of the Clean Air Act (Interstate Transport) 

Dear Dave, 

On April 10, 2007, Tina Anderson submitted a request on your behalf for a letter of 

advice as to whether Wyoming lawfully adopted Wyoming's State Implementation Plan 

(SIP) revision required pursuant to Section 110(a)(2)(D)(i) of the Clean Air Act 

(CAA)(Interstate Transport Provision) . 

When a new National Ambient Air Quality Standard (NAAQS) is promulgated, the 

Interstate Transport Provision requires states to submit SIPs addressing emissions that may 

affect neighboring states through interstate transport. In 1997, EPA issued new NAAQS for 

ozone and particulate matter with a diameter of 2 .5 micrometers or smaller (PM2 .5). See 62 

Fed. Reg. 38,652 (PM2 .5), 62 Fed. Reg. 38,856 (ozone). On April 25, 2005, EPA found that 

state SIPs failed to meet the requirements of the Interstate Transport Provision. 70 Fed. Reg. 

21147. States must submit a SIP and obtain EPA approval by May 25, 2007 or they will be 

subject to a Federal Implementation Plan (FIP) . 

In August and September 2006, EPA issued guidance to the states for preparing SIPs 

satisfying the Interstate Transport Provision. Following this guidance, Wyoming Department 

of Environmental Quality, Air Quality Division (DEQ/AQD) developed an Interstate 
Dave Finley 

Re: Section 110(a)(2)(D)(i) 

April 24, 2007 

Pg2of2 

Transport SIP making a negative declaration to demonstrate that : 1) Wyoming does not 

contribute to non-attainment or interfere with maintenance of the ozone or PM2.5 standards 

in other states ; 2) Wyoming's Prevention of Significant Deterioration (PSD) rule ensures 

that Wyoming does not interfere with PSD implementation in other states ; 3) Wyoming 

emissions sources do not interfere with the implementation of Reasonably Attributable 

Visibility Impairment (RAVI) in other states ; and, 4) Wyoming is still assessing the impact 

of transported pollution on visibility in federally protected areas and will be submitting a 

Regional Haze SIP addressing such impacts by December, 2007 . 

Wyoming's legislature has authorized the DEQ Director to perform "any and all acts 

necessary" to carry out the purpose of the Environmental Quality Act. See WYO. STAT. ANN. 

§§ 9-2-2013 ; 35-11-102,-109 and -110. Specifically, the DEQ Director is authorized to 

consult and cooperate with the federal government and "represent Wyoming in any matters 

pertaining to plans . . . relating to environmental enhancement and protection ." WYO. STAT. 

ANN. §- § 35-11-109 (a)(ii) and (viii) . All plans prepared by the DEQ must be submitted to the 

governor for review and approval. WYO. STAT. ANN. § 9-1-208. Thus, the statutory scheme 

vests the DEQ Director with the authority and responsibility to develop and adopt CAA SIPS. 

Then, the Governor approves the SIP and either the Governor or his designee submits the SIP 

to EPA. 

In connection with this letter of advice, I have reviewed Section 110(a)(2)(D)(i) of the 

CAA, the Wyoming Environmental Quality Act, the SIP Public Hearing Notice, the minutes 

from the December 11, 2006, Air Quality Advisory Board meeting, the DEQ/AQD SIP 

Certification Page, and Wyoming's Interstate Transport SIP . Based upon my review, it is 

my opinion that WDEQ, upon approval by the Governor, has the authority to adopt and 

implement the Interstate Transport SIP and complied with state law in adopting the SIP. 

Please call me if you have any questions. 

Vehr 

't . Attorney General 
The Wyoming Department of Environmental Quality 

Air Quality Division 

(WDEQ-AQD) 

The Wyoming Air Quality Advisory Board will meet on December 11, 2006, in the Conference 

Room of the Casper DEQ Field Office, 152 N. Durbin, Suite 100, Casper, Wyoming at 10 :00 

AM. The Air Quality Division (AQD) is requesting the Board's consideration of a State 

Implementation Plan (SIP) for Interstate Transport to satisfy the requirements of Section 

110(a)(2)(D)(i) of the Clean Air Act for ozone and particulate matter . AQD is also proposing 

revisions to Wyoming Air Quality Standards and Regulations (WAQS&R) Chapters 3, 5, and 11 . 

Most of the changes to Chapter 3, General Emission Standards, Chapter 5, National Emission 

Standards and Chapter 11, National Acid Rain Program are updates to the annual effort to adopt 

by reference from the Code of Federal Regulations . The Division is also making minor 

corrections to these chapters . Some of the revisions in Chapter 3 involve changes to the SIP. 

The public is invited to attend and provide oral or written comments to the Board and AQD on 

all matters before the Board. Comments submitted by email will not be included in the public 

record . Electronic copies of the rule changes and the proposed Interstate Transport SIP will be 

available after November 13, 2006 at http ://deq .state .wy.us/aqd/index.asp?pageid=8. If you have 

questions on the rule changes or request hard copy format, please contact Christine Anderson at 

307-673-9337. 

For additional information contact David A. Finley, Administrator, Air Quality Division at 307-

777-7391 . 

In accordance with the Americans with Disabilities Act, special assistance or alternative formats 

will be made available upon request for individuals with disabilities . 
AQAB Meeting of 12/11/06 

Public Notice 

Newspaper Date of Publication 

Casper Star Tribune November 10, 2006 

Gillette News-Record November 10, 2006 

Wyoming Tribune Eagle November 11, 2006 

Rock Springs Daily Rocket Miner November 11, 2006 

Cody Enterprise November 13, 2006 
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WYOMING AIR QUALITY ADVISORY BOARD 

MEETING AGENDA 

December 11, 2006 at 10 :00 AM 

WDEQ Casper Field Office - Conference Room 

152 N. Durbin, Suite 100 

Casper, Wyoming 

I. CALL TO ORDER 

II . APPROVAL OF MEETING MINUTES FOR JULY 10-11, 2006 MEETING 

III. OLD BUSINESS 

A. Staff Activity 

1 . Hiring Status 

2 . Reorganization of the Monitoring Program 

B. Enforcement Activities Report 

C. Status Update on Previous Board Activities and Other Old Business 

IV. NEW BUSINESS 

A. Proposed Interstate Transport State Implementation Plan (SIP) 

B. Proposed Changes to Wyoming Air Quality Standards and Regulations: 

Chapter 3, General Emission Standards, Section 2, Emission standards for 

particulate matter, Section 6, Emission standards for volatile organic compounds 

and Section 8, Emission standards of asbestos for demolition, renovation, 

manufacturing, spraying and fabricating 

Chapter 5, National Emission Standards, Section 2, New source performance 

standards and Section 3, National emission standards for hazardous air pollutants 

Chapter 11, National Acid Rain Program, Section 2, Acid rain program 

V. SCHEDULE NEXT MEETING 

VI . ADJOURN 
WYOMING STATE IMPLEMENTATION PLAN 

INTERSTATE TRANSPORT 

TO SATISFY THE REQUIREMENTS OF CLEAN AIR ACT 110(a)(2)(D)(i) 

FOR THE 8-HOUR OZONE AND PM2.5 NAAQS 

PROMULGATED IN JULY 1997 

Presented Before the Wyoming Air Quality Advisory Board 

December 11, 2006 
WYOMING STATE IMPLEMENTATION PLAN 

A. Introduction 

The Clean Air Act, § 110(a)(2)(D)(i), requires that each state implementation plan (SIP) 

submitted to EPA must address emissions that affect other states through interstate transport. In 

addition, states must ensure that no SIP interferes with another state's program to prevent 

significant deterioration of its air quality, or interferes with visibility in another state. Until 

August 2006, there had been no EPA guidance as to the appropriate scope of such a SIP . 

On April 25, 2005, in response to a lawsuit, EPA published (70 FR 21147) a finding that states 

had failed to submit SIPs meeting the requirements of 110(a)(2)(D)(i) within three years after 

EPA issued new National Ambient Air Quality Standards (NAAQS) for ozone and PM2.5 in 

1997 . The finding requires that EPA issue a Federal Implementation Plan (FIP) for any state that 

does not submit a SIP and obtain EPA approval of it by May 25, 2007. 

On August 15, 2006, EPA issued final guidance to states for preparation of SIPs that satisfy the 

110(a)(2)(D)(i) requirements, and, on September 11, 2006, added a supplement to the guidance. 

There are four components of 110(a)(2)(D)(i) that must be addressed. The first two, 

demonstrating adequate provisions to prevent emissions from Wyoming from interfering with 

attainment or maintenance of the federal NAAQS in any other state, are discussed together in 

Part B below. The requirement that Wyoming show no interference with another state's program 

to prevent significant deterioration of its air quality is found in Part C below, and discussion of 

Wyoming's influence on visibility is found in Part D below. 

B. Nonattainment and Maintenance Area Impact 

The "good neighbor" provisions of § 110(a)(2)(D)(i) require that state SIPs prohibit 

any source or other type of emissions activity within the State from emitting any air 

pollutant in amounts which will-- 

(I) contribute significantly to nonattainment in, or interference with maintenance 

by, any other state with respect to any such national primary or secondary 

ambient air quality standard. . . 

To demonstrate that emissions from Wyoming do not contribute to nonattainment or interfere 

with maintenance of the ozone or PM2.5 standards issued in 1997, Wyoming relies on modeling 

work conducted by EPA to determine which states were to be covered by the Clean Air Interstate 

Rule (CAIR). In the final CAIR rule, published on May 12, 2005, EPA described how it 

determined which states were subject to the rule because they contributed to ozone 

nonattainment in any state. EPA's first step was to remove from consideration those states 

whose upwind contributions were very low. "Specifically, EPA considered an upwind State not 

to contribute significantly to a downwind nonattainment area if the State's maximum 

contribution to the area was either (1) less than 2 ppb, as indicated by either of the two modeling 
techniques ; or (2) less than one percent of the total nonattainment in the downwind area." (See 

Footnote 44, page 25191 of Vol. 70, No . 91, FR May 12, 2005). With respect to ozone, EPA 

determined in the technical work done for the CAIR rule, that Wyoming did not contribute to 

downwind nonattainment. On EPA's website for the Clean Air Interstate Rule, EPA states : 

The final Clean Air Interstate Rule covers 28 eastern states and the District of Columbia. 

Air emissions in these states contribute to unhealthy levels of ground-level ozone, fine 

particles or both in downwind states . Several states are not included in the CAIR region 

because they do not contribute to downwind nonattainment. These states include: 

Alaska, Arizona, California, Colorado, Hawaii, Idaho, Kansas, Maine, Montana, 

Nebraska, Nevada, New Hampshire, New Mexico, North Dakota, Oklahoma, Oregon, 

Rhode Island, South Dakota, Utah, Vermont, Washington, and Wyoming. 

Finally, the closest nonattainment area for ozone (Las Vegas - Clark County) is approximately 

400 miles away from the southwest border of Wyoming. Considering the magnitude of the 

population associated with the Clark County Ozone Nonattainment Area and the geological and 

topological separation of Clark County from Wyoming, it is unlikely that Wyoming is a 

significant contributor to the nonattainment status in the Las Vegas area. 

With respect to determining whether Wyoming contributes to nonattainment or maintenance of 

the PM2.5 standard in other states, again Wyoming relies on EPA modeling methodology. EPA 

says, 

Regarding modeling of all States, in the PM2.5 modeling for the NPRM, we modeled 41 

States, and found that the westernmost of these States made very small contributions to 

nonattainment in any other State.' For the revised modeling for the final rule, we 

reduced the set of States modeled [from 41 to 37 for PM - the additional 4 states NOT 

rnodeled for the final rule are Montana, Wyoming, Colorado, and New Mexico] for 

reasons of efficiency. The results again showed that the westernmost States modeled did 

not make contributions above the significance threshold, indicating that had other even 

more western States been modeled they also would not have done so.' 

The closest PM2.5 nonattainment area is in Libby, Montana, which is approximately 325 miles 

upwind of the northern border of Wyoming. The technical support document submitted for the 

Libby, Montana area indicates that the sources of PM2.5 are localized problems due to 

topography and meteorological factors. It is unlikely that Wyoming, which is downwind from 

the nonattainment area, contributes to the nonattainment status of Libby, Montana. 

Based on the conclusions stated by the EPA in the above-cited guidance and the relative distance 

to nonattainment areas, the State of Wyoming agrees that emissions from Wyoming do not 

significantly affect nonattainment or maintenance areas in other states . 

1 The 9 westernmost states that were NOT modeled for the NPRM are Idaho, Washington, Oregon, Nevada, 

California, Utah, Nevada, Alaska, and Hawaii. 

2 Corrected Response To Significant Public Comments On the Proposed Clean Air Interstate Rule, March 2005, 

Corrected April 2005, Document ID No. EPA-HQ-2003-0053-2172, pages 200-201 . 
C. Impact on PSD 

In § 110(a)(2)(D)(i)(II), the Clean Air Act requires that states prohibit emissions within the state 

from interfering "with measures required to be included in the applicable implementation plan 

for any other State under part C to prevent significant deterioration of air quality. . ." 

EPA guidance indicates that states with SIPs addressing Prevention of Significant Deterioration 

(PSD) and Nonattainment New Source Review (NNSR) have adequately demonstrated that they 

do not affect PSD implementation in other states : 

For the 8-hour ozone standard, each State only needs to make a SIP submission that 

confirms that major sources in the State are currently subject to PSD and NNSR 

permitting programs that apply to the 8-hour ozone standard and that SIP-approved 

States are on track to meet the June 15, 2007 deadline for SIP submissions adopting the 

requirements of the Phase II ozone implementation. rule. 

For the PM-2.5 standard, States need only provide a SIP submission that confirrns that 

major sources in the State are subject to PSD and NNSR permitting programs 

implemented in accordance with EPA's interim guidance calling for use of PM-10 as a 

surrogate for PM-2.5 in the PSD and NNSR programs. 3 

Wyoming has a fully-approved PSD program, and has successfully implemented this program 

for many years. Wyoming's PSD rules were revised effective October 6, 2006, to conform with 

the federal NSR Reform rules. These changes have not yet been submitted to EPA and are not 

yet approved. With regard to being on track to meet the June 15, 2007 deadline for SIP 

submission adopting requirements of the Phase II ozone implementation rule, Wyoming has 

initiated the review of these changes, and will be working on rule revision over the next year. 

Until any of these changes are approved, the previously-approved versions are federally 

enforceable. Wyoming does not have a NNSR (nonattainment new source review) program 

since there has not been a need for one to date. Wyoming will update its PSD program to 

include a NNSR program in the future if the need should arise. Wyoming will implement the 

current rules in accordance with EPA's interim guidance using PM10 as a surrogate for PM2.5 in 

the PSD program. 

Based on the conclusions stated by the EPA in the above-cited guidance, the State of Wyoming 

concludes that Wyoming's PSD SIP rule ensures that Wyoming does not interfere with PSD 

implementation in other states . 

D. Effects on Visibility 

The final requirement of § 110(a)(2)(D)(i)(II) is that states prohibit emissions within the state 

from interfering with the programs of other states to protect visibility . In 1980, EPA issued 

regulations that required states to address reasonably attributable visibility impairment (RAVI). 

EPA's recent guidance states that : 

3 SIP Guidance on Section 110(a)(2)(D)(i) Findings of Failure to Submit, August 11, 2006, page 2 . 
At this point in time, EPA has made no determination that emissions from any State 

inte7fere with measures required to be included in a plan to address reasonably 

attributable visibility impairment. Further, EPA is not aware of any certification of 

existing reasonably attributable impairment of visibility by a Federal Land manager that 

has not already been resolved. The EPA accordingly believes that States should be able 

to make a relatively simple SIP submission verifying that no source within the State emits 

pollutants that interfere with measures included in the visibility SIPs under the 1980 

regulations . 4 

Based on the conclusions stated by the EPA in the above-cited guidance, the State of Wyoming 

concludes that there are no Wyoming sources of emissions that interfere with implementation of 

RAVI SIPs in other states . 

Because states are not required to submit Regional Haze SIPs until December 2007, it is 

probably too early to assess the impact of transported pollution on visibility in federally 

protected areas . EPA's guidance states that : 

EPA believes that it is currently premature to determine whether or not State SIPs for 8-

hour ozone or PM2.5 contain adequate provisions to prohibit emissions that interfere 

with measures in other States' SIPs designed to address regional haze. Accordingly, 

EPA believes that States may make a simple SIP submission conf rming that it is not 

possible at this time to assess whether there is any inte7ference with measures in the 

applicable SIP for another State designed to "protect visibility "for the 8-hour ozone and 

PM2.5 NAAQS until regional haze SIPs are submitted and approved. s 

Wyoming, however, submitted its first Regional Haze SIP to EPA in December 2003 under 40 

CFR 51 .309, already demonstrating reasonable progress in reducing impacts on Class I areas on 

the Colorado Plateau. The 2007 SIP update will analyze any impacts from Wyoming that extend 

beyond the Colorado Plateau and determine appropriate long-term strategies for control 

measures. 

`` Guidance for State Implementation Plan Submissions to Meet Current Outstanding Obligations Under Section 

110(a)(2)(D)(i) for the 8-Hour Ozone and PM2.5 National Ambient Air Quality Standards, EPA, August 15, 2006, 

page 9. 

' Guidance for State Implementation Plan Submissions to Meet Current Outstanding Obligations Under Section 

110(a)(2)(D)(i) for the 8-Hour Ozone and PM2.5 National Ambient Air Quality Standards, August 15, 2006. Pages 

9-10 .