UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IX 75 Hawthorne Street San Francisco, CA 94105·3901

OFFICE OF THE REGIONAL ADMINISTRATOR 

## JUN 14 2011

The Honorable Mary Resvaloso Chairwoman Torres Martinez Desert Cahuilla Indians P.O. Box 1160 Thermal, California 92274

DearChairwoman Resvaloso:

Thank you for yourTribe's recommendation regarding the air quality designation for the revised National Ambient Air Quality Standards for lead, submitted byJonathan Chapman on behalfofthe Torres MartinezDesert CahuillaIndians. This letter is to notify you ofthe U.S. Environmental Protection Agency's (EPA's) preliminary decision to designate theTorres Martinez DesertCahuilla reservation as unclassifiable/attainment, and to inform you ofour approach for completingthe designations for the revised lead standard.
Reducing levels oflead pollution is an importantpart ofthe EPA's commitment to a clean, healthy environment. Lead exposure can cause a range ofadverse health effects, most notably in children. Exposures to low levels ofIead earlyin life have been linked to effects on IQ, learning, memory, and behavior.

On October 15,2008, the EPA substantially strengthened the health-based or "primary"National Ambient Air Quality Standard for lead by lowering it from 1.5 micrograms percubic meter

### (~g/m3) - a level set in 1978

- to a level of0.15**~glm3.** This stronger standard provides increased protection against adverse health effects associated with exposure to lead in at-risk groups, includingchildren. To provide increased protection against lead-related environmental and other welfare effects, the EPA revised the secondaryNational Ambient Air Quality Standard to be identical in all respects to the revised primary standards. The EPA also determined that thepre-existing ambient lead monitoring network was inadequate for determining whether many areas are meetingthe revised lead standards and established
new criteria for siting ambient lead monitors and new data collectionrequirements. Monitors meeting the new network sitingrequirements were to begin operation January 1, 2010.

Within two years ofpromulgatingnew orrevised National Ambient Air Quality Standards, th Clean Air Act requires the EPA to completethe initial process ofidentifying ordesignating areas that meet or do not meet an air quality standard. Ifthe Administratorhas insufficient infonnation to make these designations, the EPA has the authority to extend the designation process by up to one year. In light of the new monitoring network, the EPA is completing the lead designations in two rounds. In the first round, completed on November 16, 2010, the EPA designated as "nonattainment" 16 areas as violating

Prinrt!d on Recyclt!d Paperthe 2008 Lead National Ambient Air Quality Standardsbased on data from the pre-2010 monitoring network. For all other areas, the EPA extended the deadline for designations by up to one year so that data from the newly deployed monitors can be considered in making appropriate designation decisions. Tribes were given an opportunity to update theirrecommendation letters for those remaining areas for

ourconsideration in the second round ofdesignations by December 15,20I

### O. The EPA intends to complete the second round oflead designations no later than October 14, 2011.

Consistent with the Clean Air Act, and after carefully consideringthe Torres Martinez Desert Cahuilla Indians' recommendation letter and all the associated technical information for the 2008 Lead National Ambient Air Quality Standards, including the mostrecent air quality data from 2008-2010, the EPA is proposingto designate the Torres Martinez Desert Cahuilla Indian reservation as unclassifiable/attainment. TheEPA uses this designation for initial designations to identify areas that have data indicating attainment, or where there is no evidence ofa violation.

Ifyou have additional information that the EPA should consider with respect to our proposed modification to your designation recommendation, please submitit to us by August 15, 2011. The EPA's preliminary designation decisions and supporting documentation will bemade available to the general public for review. We will be acceptingcomments through August 15,2011. We will review any information we receive from the Torres Martinez Desert CahuillaIndians, the StateofCalifornia, and the general publicby this date, and we plan to promulgatethe second round offinal designations by October 14, 2011.

We look forward to a continued dialogue with you and your staffas we work together to implement the 2008 LeadNational AmbientAirQuality Standards. Should you have any questions, please do not hesitate to call me, orhave your staffcontact Associate Air Division Director Colleen McKaughan at 520-498-0118.

cc: Gerardo Bojorquez Environmental Specialist