UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 


REGION 10 


1200 Sixth Avenue. Suite 900 

Seattle. Washington 98101-3140 

OFFICE OF THE JUN 1 3 2011 REGIONAL ADMINISTRATOR 

The Honorable C. L. "Butch" Otter 

Governor ofthe State of Idaho 

Post Office Box 83720 

Boise, Idaho 83720 

Dear Governor Otter: 

Thank you for your recommendations on air quality designations for the revised National 

Ambient Air Quality Standards for lead throughout Idaho. This letter is to notify you ofthe U.S. 

Environmental Protection Agency's preliminary decision to designate all ofIdaho as 

unclassifiable/attainment and to inform you ofour approach for completing the designations for 

the revised lead standards. Reducing levels oflead pollution is an important part ofthe EPA's 

commitment to a clean, healthy environment. Lead exposure can cause a range of adverse health 

effects, most notably in children. Exposures to low levels of lead 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 

Ambient Air Quality Standard by lowerinf it from 1.5 micrograms per cubic meter (jJg!m3

) a 

level set in 1978 - to a level of 0.15 jJg!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 other welfare 

effects, the EPA revised the secondary National 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 standards and established new criteria for siting ambient lead monitors 

and new data collection requirements. Monitors meeting the new network siting requirements 

were to begin operation January 1, 2010. 

Within two years of promulgating new or revised National Ambient Air Quality Standards, the 

Clean Air Act requires the EPA to complete the initial process ofidentifying or designating areas 

that meet or do not meet an air quality 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. In light ofthe new monitoring network, the EPA is completing the lead designations in 

two rounds. In the first round, published on November 16,2010, the EPA designated as 

"nonattainment" 16 areas as violating the 2008 Lead National Ambient Air Quality Standards 

based on data from the pre-201 0 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. States were given an opportunity to 

update their recommendation letters for those remaining areas for our consideration in the second 
round of designations by December 15,2010. The EPA intends to complete the second round of 

lead designations by no later than October 14, 2011. 

Consistent with the Clean Air Act, and after carefully considering Idaho's September 30, 2009, 

recommendation letter and all the associated technical information for the 2008 Lead National 

Ambient Air Quality Standards, including the most recent air quality data from 2008-2010, the 

EPA is proposing to adopt State's recommended designation and boundary. 

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

implement the 2008 Lead National Ambient Air Quality Standards. Should you have any 

questions, please do not hesitate to call me, or have your staff contact Mr. Steve Body at (206) 

553-0782. 

Sincerely, 

~C).~ Dennis J. McLerran 

Regional Administrator 

cc: 	 Toni Hardesty 

Director, Idaho Department of Environmental Quality 

Martin Bauer 

Air Program Manager, Idaho Department of Environmental Quality 

Gina McCarthy 

Assistant Administrator for Air and Radiation, EP A 

Steve D. Page 

Director, Office ofAir Quality Planning and Standards, EPA