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Pacific Southwest, Region 9

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

Air Actions, Nevada

NOTE: This content is no longer being updated. The most up to date information can be found in Federal Register Notices and Approved Air Quality Implementation Plans in Region 9.

The Mohave Generating Station & Grand Canyon Visibility

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Update on Mohave Generating Station

On December 31, 2005, the operator of the Mohave Generating Station, a coal-fired power plant located near Laughlin, Nevada, permanently closed the facility.


In August 1997, the Department of the Interior (DOI) sent a letter to EPA reaffirming the Department's 1985 certification of visibility impairment at the Grand Canyon National Park. This letter also stated the Department's belief that the Mohave Generating Station is contributing to the impairment.

The DOI requested that if EPA agreed with the Department's assessment, and found that visibility impairment at the Grand Canyon is "reasonably attributable" to the Mohave Generating Station, that EPA require the power plant to install "Best Available Retrofit Technology," in keeping with EPA visibility regulations.

Since EPA received the August 1997 letter, the Agency has been working closely with DOI, including the National Park Service, to address the concerns raised by the Department. In addition, EPA and DOI have been working together with other parties that have an interest in the future of the power plant. These include the owners of the facility, the Hopi Tribe and Navajo Nation, who provide the coal that is burned at the facility, the local communities, and several environmental groups.

Summary of Past EPA Actions

February 2002: Final Rule

On February 8, 2002, after consideration of the comments, EPA issued the final rule to revise the federal implementation plan for visibility protection in the State of Nevada to include emission reduction requirements for the Mohave Generating Station.

EPA adopted these requirements to resolve the concerns raised by DOI regarding the impact of sulfur dioxide (SO2) emissions from the Mohave Generating Station on visibility impairment at Grand Canyon National Park. The requirements are based on a consent decree entered into by the owners of the Mohave Generating Station and the Grand Canyon Trust, the Sierra Club, and the National Parks Conservation Association. The consent decree resolves a lawsuit brought by the environmental groups against Mohave Generating Station owners for alleged violations of SO2 and opacity limits.

July 2000: Proposed Rule

On July 20, 2000, EPA published a proposed rule which provided a 30-day public comment period.

Advance Notice of Proposed Rulemaking

On June 17, 1999, EPA issued an Advance Notice of Proposed Rulemaking that provides background information regarding the Mohave Generating Station and Grand Canyon visibility and sought public input on these issues.

Project MOHAVE Report

On March 19, 1999, EPA released the final Project MOHAVE report, which presents the results of a seven-year study to assess the impact that the Mohave Generating Station emissions have on visibility at the Grand Canyon.

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