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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Sulfur Dioxide in Morenci, AZ

Sulfur Dioxide in Morenci, AZ

March 30, 2004: Approval of Arizona's Plan to Meet the Sulfur Dioxide Air Quality Standards in the Morenci Area

EPA has approved Arizona's maintenance plan to maintain attainment of the short-term (24-hour) and long-term (annual) primary National Ambient Air Quality Standards (NAAQS) for sulfur dioxide (SO2) in the Morenci area, as well as Arizona’s request to redesignate this area from nonattainment to attainment for SO2.

The Morenci area has not had a violation of either the annual or the 24-hour health-based standard since 1984. The primary source of sulfur dioxide pollution in the Morenci area was the Phelps Dodge Morenci Incorporated smelter, which ceased operation in late 1984 and was dismantled in 1995 and 1996. There are currently no other SO2 sources of this magnitude in Morenci.

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Contact Information

Wienke Tax
Office of Air Planning, EPA Region 9
Email: tax.wienke@epa.gov
Phone: (520) 622-1622.


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