Terry RamblerChairman

San Carlos Apache Tribe

P.O. Box 0

San Carlos, Arizona 85550

Dear Chairman Rambler:

This letter regards air quality designations for the San Carlos Apache Tribe for the 2010 revision to the

primary National Ambient Air Quality Standard for sulfur dioxide (SO 2).Reducing levels of SO2

pollution is an important part ofthe U. S. Environmental Protection Agency’s (EPA) commitment to a

clean, healthy environment. Exposure to SO2can cause a range of adverse health effects, including

narrowing ofthe airways which can cause difficulty breathing and increased asthma symptoms. This

letter is to notify you ofthe EPA’s preliminary intention to defer designation of Indian country ofthe

San Cabs Apache Tribe, and of our intention to designate two nearby areas, Hayden and Miami, as

nonattainment.

On June 3, 2010, the EPA strengthened the health-based or “primary” standard for SO2by establishing astandard for 1-hour average SO2concentrations at a level of 75 parts per billion. The Clean Air Act

requires the EPA to complete the initial designations process within two years of promulgating a new orrevised standard. Ifthe Administrator has insufficient information to make these designations, the EPA

has the authority to extend the designation process by up to one year. On July 27, 2012, the EPAannounced that it had insufficient information to complete the designations for the 1-hour SO2standard

within two years and extended the designations deadline to June 3, 2013.At this time the EPA is proceeding with designating as nonattainment most areas in locations whereexisting monitoring data from 2009-2011 indicate violations ofthe 1-hour SO2standard. The EPA

intends to address the designations for all other areas in separate future actions. With input from adiverse group of stakeholders, EPA has developed a comprehensive implementation strategy for these

future actions that focuses resources on identifying and addressing unhealthy levels of SO2.Thestrategy is available at: www.epa.gov/airguality/sulfurdioxide/implement.html. The EPA will continue

to work closely with you and our other partners at the state, tribal and local levels to ensure healthprotective, common sense implementation ofthe 1-hour SO2standard.

The EPA’s review of the most recent monitored air quality data in Arizona from 2009-2011 shows that

only monitors in Hayden and Miami are violating the 2010 SO2standard. We do not believe these

monitors represent the S02 concentrations on your reservation, nor do we believe there are SO2sources

Printed on Reyc1ed Paper
120 days prior to promulgating any final designations.

We look forward to a continued dialogue with you and your staff as we work together to implement the

2010 primary SO2standard. For additional information regarding initial designations ofthe SO2

standard, please visit our website at: www.epa.gov/so2designations. Should you have any questions,

please do not hesitate to call me, or have your staff contact Deborah Jordan, Director, Air Division at

415-947-8715, or j ordan.deborah(epa.gov.

Sincerely,

,Jared Blumenfeld

cc: Loretta Stone, Director, San Carlos Environmental Protection Agency

Gina McCarthy, Assistant Administrator for Air and Radiation

Stephen D. Page, Director, Office of Air Quality Planning and Standards