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Pacific Southwest, Region 9

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

Air Actions, Nevada

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

Grand Canyon Visibility: Proposed Revision to Nevada Visibility FIP

EPA is proposing to revise the federal implementation plan for visibility protection in the State of Nevada (Nevada Visibility FIP) to include emissions reduction requirements for the Mohave Generating Station. The proposed requirements are based on a consent decree entered into by the owners of MGS (Southern California Edison, Nevada Power, Salt River Project, and Los Angeles Department of Water and Power) and the Grand Canyon Trust, the Sierra Club, and the National Parks and Conservation Association.

On February 19, 1998, the Grand Canyon Trust (GCT) filed a citizen suit against the owners of MGS alleging violations of SO2 and opacity limits. The Sierra Club and the National Parks and Conservation Association subsequently joined GCT as plaintiffs in the suit. Following EPA's publication of the June 17, 1999, ANPR regarding MGS's impact on visibility at the Grand Canyon, the environmental groups and MGS owners settled the lawsuit and entered into a consent decree requiring emissions reductions of SO2, nitrogen oxides (NOx) and particulate matter. The National Park Service (NPS) then indicated to EPA that MGS's compliance with the emission limits contained in the Mohave consent decree would address the concerns expressed in the Department of the Interior's 1997 letter to EPA regarding the impact of SO2 emissions from MGS on visibility impairment at GCNP. NPS also indicated that adoption of the consent decree provisions into the Nevada Visibility FIP is an appropriate means of resolving these concerns. EPA agrees and is therefore proposing to revise the Nevada Visibility FIP accordingly.

Under the terms of the consent decree and EPA's proposed rule, MGS owners will install lime spray dryer technology to reduce visibility impairing SO2 emissions from each of the two boilers at the plant by 85%. MGS owners will also install baghouses to reduce particulate matter emissions and meet an opacity limit of 20%. In addition, new burners will be installed in the boilers to reduce emissions of NOx. MGS must comply with the pollution control requirements by 2006.

A 30-day public comment period will begin when EPA publishes the Proposed Rule in the Federal Register. An unofficial copy of EPA's proposed rule is available below in WordPerfect format; a link to the official online version will be provided upon Federal Register publication. After reviewing the comments received in response to this proposal, EPA will determine how to proceed with a final rule. For further information:

For More Information

Please contact Bruce Polkowsky of the National Park Service at (303) 987-6944.

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