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

8P-AR 

# 'JUN 14 2011.

The Honorable Matthew H. Mead Governor ofWyoming State Capitol Cheyenne, Wyoming 82002

Dear GovernorMead:

Thankyou for yourrecommendations on air quality designations for the revised National AmbientAir Quality Standards for lead throughout Wyoming. This letter is to notify you ofthe U.S. Environmental Protection Agency's (EPA's) preliminary decision to designate all of Wyoming as attainmentlunclassifiable, and to inform you ofour approach for completing the designations for the revised lead standards. Reducing levels oflead pollution is an importantpart ofthe EPA'scommitmentto a clean, healthy environment. Lead exposure can cause a range of adverse health effects, most notably inchildren. Exposures to low levels oflead early in 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 AmbientAir Quality Standard by**lowerin~** it from 1.5 micrograms per cubic meter (llg/m3) - a level set in 1978

- to a level of0.15 Ilg/m

. This stronger standard provides increased protection against adverse health effects associated with exposure to lead in at-risk groups, including children. To provide increased protection against lead-related environmental and otherwelfare effects, the EPA revised the secondaryNational Ambient Air Quality Standard to be identical in all respects to the revised primary standard. The EPA also determined that the pre-existing ambient lead monitoring network was inadequate for determining whether many areas are meeting the revised lead standard and established new criteriafor siting ambient lead monitors and new datacollection requirements. Monitors meeting the new network siting requirements
were to begin operation January 1,2010.

Within two years ofpromulgating new orrevised National Ambient Air Quality Standards, the Clean AirAct requires the EPA to complete the initial process ofidentifying or designating areas that meet ordo not meet an air quality standard. Ifthe Administratorhas insufficient information to make these designations, the EPA has the authority to extend the designationprocess by up to one year. In light ofthe new monitoring network, the EPA is completing the lead designations in two rounds. In the first round, published onNovember 16,2010,the EPA designated as "nonattainment" 16 areas as violating the 2008 LeadNational Ambient Air Quality Standards based on data from the pre-201O monitoring network. For all other areas, the EPA extended thedeadline for designations by up to one year so that data from the newly deployed monitors can be considered in making appropriate designation decisions. States were given an opportunity to update theirrecommendation letters for those remaining areas for our consideration in the second round ofdesignations by December 15, 2010. The EPA intends to complete the second round of lead designations by no laterthan October 14, 2011.

Consistent with the Clean Air Act, and after carefully considering Wyoming's October 8,2009 recommendation letter, and all the associatedtechnical information for the 2008 Lead National Ambient Air Quality Standards, including the most recent air quality datafrom 2008-2010, the EPA is proposing to adopt Wyoming'srecommended designations.

Ifyour state has additional informationthatthe EPA should consider with respect to our proposed modificationto your designation recommendation, please submit it to us by August 15,2011. The EPA'spreliminary designation decisions and supporting documentation will be made available to the general public for review. We will be accepting comments through August 15,2011. We will review any information we receive from the state ofWyoming and the general public bythis date, and we planto promulgate the second round offinal designations by October 14,2011.

We look forward to a continued dialogue with you and your staffas we worktogether to implementthe 2008 Lead National Ambient Air Quality Standards. Should you have any questions, please do not hesitate to call me, orhave your staffcontact Carl Daly ofmy staffat (303) 312-6416.

Sincerely,

cc: John V. Corra, Environmental Director Wyoming DepartmentofEnvironmental Quality

GinaMcCarthy, AssistantAdministrator for Air and Radiation StevenD. Page, Director, Office ofAir Quality Planning and Standards