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



## AUG2 02014

Henry R. Darwin, Director ArizonaDepartment ofEnvironmental Quality 1110 WestWashington Street Phoenix, Af ona 85007 Djwin:

Thankyou foryourletter ofJune 20, 2014, in which you requested thatthe Environmental Protection Agency (EPA) delay its proposedredesignation ofthe Hayden areato nonattainment forthe 2008 national ambient air quality standard (NAAQS) for lead (Pb). Iii support ofyour request, you: 1) notedthatADEQ’s Globe Highwayhas notmeasured a violation ofthe Pb NAAQS since 2012, whenASARCO installed controls; 2) raised concerns aboutthe representativeness ofthe data from the ASARCO monitors; and 3) suggestedthat a state implementation plan (SIP) forthe control oflead would duplicate the requirements ofthe sulfur dioxide (SO 2 ) plan, which is due in April of2015 and which you believe will reduce Ph concentrations in the area. Regional AdministratorBlumenfeld has askedthat I respond on his behalf.

The EPA commends the 2012 installation ofpollution control equipment on the anode furnaces atthe ASARCO facility and understands thatthe equipmentmighthave resulted in areduction of ambientPb concentrations, as measured atthe Globe Highwaymonitor. However, based on violations recorded in 2012 and on the form ofthe PbNAAQS (i.e., three consecutive calendar years without a violation are requiredbefore an area canbe consideredto be attaining the standard), the monitorcontinues to violate the Pb NAAQS.

As you observed, the Clean AirActprovides the Administratorwith broad authority to consider air quality data or any other air quality-related considerations she deems appropriate in determining whetherto redesignate an areato nonattainment. Accordingly, in addition to considering the data from ADEQ’s Globe Highway monitor, we also reviewed data gatheredby the more extensive monitoring networkrecently installedbyASARCO. Datarecorded by the ASARCO monitors indicate that the Globe Highway site may notbe capturing maximum ambient concentrations ofPb in the Hayden area, and thatthe area is experiencing ongoing violations ofthe PbNAAQS. While dataused as the basis for determining whether an area is violating aNAAQS mustmeet specific requirements contained within 40 CFR Part 58, any available monitoring datamaybe used to improve ourunderstanding ofwhat is occurring in an area. We also note thatthe ASARCO monitors were established formultiplepurposes, including

Pr,n!L’d on Rervcled lopercomparison to the NAAQS. The EPA’s analysis of the ASARCO data and the findings from our recent audit of the monitors give us confidence that these supplementary data provide a more complete picture of air quality in the Hayden area and that it is appropriate to include these supplementary data in our deliberations regarding redesignation. Finally, while the controls required under the Hayden SO 2 SIP could result in reductions in ambient concentrations of Pb, the EPA has not received information that quantifies the benefits of these future controls. In and of itself, an SO2 SIP is not designed to control Pb emissions and is not required to ensure that the reductions are sufficient to achieve attainment of the Pb NAAQS. Accordingly, the EPA does not agree that relying on the SO 2 plan to resolve the Pb problem will ensure expeditious attainment of the Pb standard. Exposure to Pb is a serious health concern. It causes a range of adverse health effects, most

notably in children. Exposures to low levels of Pb early in life have been linked to effects on IQ, learning, memory, and behavior. Depending on the level ol exposure. Pb can aclverseh aliect the

nervous system. kidney function. immune system. reproductive and developmental systems and the cardiovascular system. The available information indicates the general public is being exposed to Pb concentrations in excess of the NAAQS and no information has been presented that demonstrates the S02 SIP will ensure sufficient, permanent reductions in Ph concentrations. We therefore determined that it is appropriate to initiate the process for evaluating emissions and developing control strategies by redesignating the area to nonattainment for the 2008 Pb NAAQS. We look forward to working with you on the development of this plan. If you have any questions, please call me. Sincerely, Deborah JordaW Director, Air l3ivision Cc: Eric Massey, Air Director, Arizona Department of Environmental Quality (via email) Michael Sundblom, Director, Pinal County Air Quality Control District (via email)