UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGIONS 1445 ROSS AVENUE, SUITE 1200 DALLAS, TX 75202-2733 

### JUN 1 4 2010

The Honorable Brad Henry Governor ofOklahoma 2300 North Lincoln Boulevard, Room 212 Oklahoma City, Oklahoma 73105
Dear Governor Henry: Thank you for your recommendations on air quality designations for the revised National Ambient Air Quality Standards (NAAQS) for lead throughout Oklahoma. Reducing levels of lead pollution is an important part ofthe U.S. Environmental Protection Agency's (EPA) commitment to a clean, healthy environment. Lead exposure can cause a range ofadverse health effects, most notably in children. Exposures to low levels oflead early in life have been linked to effects on IQ, learning, memory and behavior. This letter is to notify you ofEPA's response to Oklahoma's designation recommendations, and to inform you ofour approach for completing the designations for the revised lead NAAQS.
On October 15, 2008, EPA substantially strengthened NAAQS for lead. The new standards, set at 0.15 micrograms per cubic meter (ug/rrr'), are 10 times tighter than the previous standards. In conjunction with strengthening the lead NAAQS, EPA also established new criteria for siting ambient lead monitors. The pre-existing ambient lead monitoring network was inadequate for determining whether many areas are meeting the revised lead NAAQS. Monitors meeting the new network siting requirements were to begin operation January 1,2010. The Clean Air Act requires EPA to complete the initial designation process within two years ofpromulgating a new or revised NAAQS. Ifthe Administrator has insufficient information to make these designations, EPA has the authority to extend the designation process by up to one year. In light ofthe new monitoring network which will generate additional information in the upcoming year, EPA intends to complete the lead designations in two rounds. In the first round, to be completed by October, 15,2010, EPA is designating as "nonattainment" any area that is violating the 2008 lead NAAQS based on data from the pre-2010 monitoring network. For all other areas, EPA is extending 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. EPA will complete the second round oflead designations no later than October 15, 2011.

We have reviewed Oklahoma's September 29,2009, recommendation letter on air quality designations and all the associated technical information for the 2008 lead NAAQS, including, if available, the most recent air quality data from 2007-2009. However, EPA is not intending to complete the initial area designations for your state at this time. Instead, EPA intends to designate all areas in your state no later than October 15,2011, in the second round oflead designations. Ifyou would like to submit updated recommendations for your areas for our

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consideration in the second round ofdesignations, we request that you do so by December 15, 201 O. For the second round ofdesignations, we will notify all states and tribes ofour preliminary responses to their recommendations no later than June 17, 2011.

We look forward to a continued dialogue with you and.your staffas we work together to implement the 2008 lead NAAQS. Ifyou have any questions, please call me at (214) 665-2100, or your staffmay call Mr. Emad Shahin ofmy staff at (214) 665-6717.

cc: Mr. J. D. Strong Secretary ofthe Environment

Mr. Steven A. Thompson Executive Director, Oklahoma Department ofEnvironmental Quality

Mr. Eddie Terrill Director, Air Quality Division, Oklahoma Department ofEnvironmental Quality