UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 6 1445 ROSS AVENUE, SUITE 1200 DALLAS TX75202-2733 

### JUN 1 4 2011

The Honorable Mary Fallin Governor ofOklahoma 2300 North Lincoln Boulevard, Suite 212 Oklahoma City, Oklahoma 73105 Dear Governor Fallin: Thankyou for yourrecommendations on air quality designations for the revised National Ambient Air Quality Standards for lead throughout Oklahoma. This letter is to notifY you ofthe U.S. Environmental Protection Agency's (EPA) preliminarydecision to designate all of Oklahoma as unclassifiable/attainment and to inform you ofour approach for completing the designations for the revised lead standards. Reducing levels oflead pollution is an importantpart ofthe EPA's commitmentto a clean, healthy environment. Lead exposure can cause arange of adverse 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. On October 15,2008, the EPA substantially strengthened the health-based or "primary" National Ambient Air Quality Standardby lowerin¥ it from 1.5 micrograms per cubic meter (fig/m3)

- a level set in 1978

- to a level of0.15 fig/m

. This stronger standardprovides 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 secondary National Ambient Air Quality Standardto be identical in all respects to the revised primary standard. The EPA also determined that the pre-existing arnbient 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 ofpromulgating new orrevised National Ambient Air Quality Standards, the Clean Air Actrequires the EPA to complete the initial process ofidentifying or designating areas that meet or do not meet an airquality standard. Ifthe Administratorhas insufficientinformation to make these designations, the EPA has the authorityto extend the designationprocess by up to one year. In light ofthenew 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-201O 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 consideredin making appropriate designation decisions. States were given an opportunityto update theirrecommendation letters for those remaining areas for ourconsideration in the second round ofdesignations by December 15, 2010. The EPA intends to complete the secondround of lead designations by no laterthan October 14, 2011.

Internet Address (URL) • http://www.epa.gov/region6 Recycled/Recyclable

_ Printed with Vegetable Oil Based Inks on 100% Recycled Paper, Process Chlorine Free

### Consistentwith the Clean AirAct, and after carefully considering Oklahoma's September29, 2009, recommendation letter and all the associated technical information forthe 2008 Lead National AmbientAir Quality Standards, including the most recent air quality data from 2008- 2010, the EPA is proposing to designate Oklahoma as unclassifiable/attainment. The EPA uses this designation for initial designations to identify areas thathave data indicating attainment, or where there is no evidence ofaviolation. The EPA's preliminary designation decisions and supporting documentation will be made available to the general public forreview. We will be accepting comments through August 15, 2011. We will review any informationwe receive from the State ofOklahoma and the general public by this date, and we plan to promulgate the second round offinal designations by October 14, 2011. We look forward to a continued dialogue with you and your staffas we worktogetherto implement the 2008 Lead National AmbientAir Quality Standards. Shouldyou have any questions, please do not hesitate to call me, orhave your staffcontactMr. GuyDonaldson ofmy staffat (214) 665-7242.

Al Armen ariz Regional Adrninistrat r

cc: Mr. Gary Sherrer Secretary ofthe Environment Mr. StevenThompson, Executive Director OklahomaDepartment ofEnvironmental Quality