UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 8 

Ref: 8P-AR 

1595 Wynkoop Street 

DENVER, CO 80202-1129 

Phone 800-227-8917 

http://www.epa.gov/region08 

MAY Z 2 2014 

Honorable Darrell O'Neal Sr., Chairman 

Northern Arapaho Tribe 

P.O. Box 396 

Ft. Washakie, Wyoming 82514 

Dear Chairman O'Neal: 

The purpose of this letter is to provide you with information concerning the U.S. Environmental 

Protection Agency's designations process for the 2012 primary annual PM2.5 national ambient air quality 

standard (NAAQS). Your tribe may find it important to engage with us in the process of assigning 

designations for Indian country. Although your involvement is not required, we would like to invite you 

to participate in the designations process and to offer you consultation. We want to ensure transparent 

and effective communication in developing area designations for the revised PM2.s NAAQS. Area 

recommendations for the PM2.s NAAQS were due to the EPA on December 13, 2013; however, the EPA 

is prepared to accept designation recommendations from tribal leaders until June 13, 2014. 

On December 13,2013, the EPA revised the PM2.s NAAQS to increase protection of public health from 

fine particle pollution. The annual PM2.5 standard was strengthened from 15 11g/m3 to 12 11g/m3

• 

Establishing initial area designations is a key step in the process of providing the health and/or welfare 

protection intended by the Clean Air Act (CAA). Within two years of promulgation of a new or revised 

NAAQS, the EPA must list and designate all areas in the country as either: 

Attainment - areas that meet the standard; 

Nonattainment- areas that either do not meet the standard, or are contributing to a nearby area 

that does not meet the standard; or 

Unclassifiable - areas where there is insufficient information to make a determination as to 

attainment. 

These designations are based on current air quality information, recommendations from state governors 

and tribal leaders, and other relevant information as discussed in the April 2013 designations guidance 

Initial Area Designations for the 2012 Revised Primary Annual Fine Particle National Ambient Air 

Quality Standard. The guidance is available on the EPA's PM Designations website at 

http://www.epa.gov/pmdesignations/2012standards/docs/april2013guidance.pdf. Additional information 

about developing tribal air quality designations is available in the September 2013 document Developing 

Designation Recommendations for Areas of Indian Country, which is available here: 

http://www.epa.gov/air/tribal/pdfs/DevelopingaDesignationRecommendationforlndianCountry.pdf. 

We are sending you this letter because your tribe has Treatment in the Same Manner as a State (TAS) 

status for designations. We will keep you informed as we finalize designations for your tribe's area and 

invite and encourage you to participate. Please notify us by June 13, 2014, ifyou are interested in 

consulting with us regarding a recommended designation. When requested, consultation will be 
conducted in accordance with the EPA Policy on Consultation and Coordination with Indian Tribes 

(www.epa.gov/tribal/consultation/consult-policy.htm). 

We plan to formally announce our intended designations for all areas by August 14, 2014. At that time 

we will send another letter to you with our intended designation and offer an additional opportunity to 

consult with us on the proposed designation status of your tribe's area of Indian country. 

In accordance with section 107(d)(l)(B) of the CAA, we are required to issue final designations for the 

PM2.s NAAQS no later than December 12, 2014. Our designations will be based on the most recent 

three calendar years of certified, quality-assured monitoring data available, and any other relevant 

information. 

As the designation process moves forward, we will keep you informed of any additional guidance or 

other support activities. We look forward to working with you to develop area designations under the 

PM2.s NAAQS in a timely manner. If your tribe is interested in consultation or has questions about the 

designations process, please do not hesitate to contact me or Crystal Ostigaard of my staff at 

(303) 312-6602 or ostigaard.crystal@epa.gov. 

cc: Ryan Ortiz, Environmental Director 

Jolene Catron, Air Coordinator 

Sincerely,