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EPA Extends Public Comment Period for Visibility rule at three Ariz. Power Plants

Release Date: 07/26/2012
Contact Information: Margot Perez-Sullivan, (415) 947-4149,

Proposed rule would improve visibility at 18 National Parks and Wilderness Areas

SAN FRANCISCO – Today, the U.S. Environmental Protection Agency extended the public comment period for a rule proposed earlier this month that would require additional pollution controls for nitrogen oxide at three power plants in eastern Ariz. The rule would improve visibility and human health at 18 national parks and wilderness areas, including the Grand Canyon, Saguaro National Park and the Petrified Forest.

EPA is soliciting public comments on the proposal through September 18, and will host two additional public hearings in Ariz. The hearings will be held on August 14, 2012 at 6 PM at Northland Pioneer College (Tiponi Community Center Conference Room) in Holbrook, Arizona, and on August 15, 2012 at 6 PM at Cochise College (Rooms 113 and 115) in Benson, Arizona. The deadline for final EPA action remains November 15, 2012.

On July 2, EPA proposed to approve Arizona’s plan that controls emissions of sulfur dioxide and coarse particles from older boilers at the Apache Generating Station, Coronado Generating Station and the Cholla Power Plant. In addition, EPA proposed a federal plan to limit nitrogen oxide (NOx) emissions at these plants. Specifically, the proposal is designed to cut NOx emissions by 7,800 tons per year at the Cholla Power Plant, 4,700 tons/year at the Apache Generating Station, and 4,500 tons/year at the Coronado Generating Station.

Under the Clean Air Act, Congress set a long-term goal of restoring natural visibility conditions in numerous national parks and wilderness areas throughout the United States, known as Class 1 Areas. One of the strategies for achieving this goal is the use of Best Available Retrofit Technology at older power plants that cause or contribute to visibility impairment at Class I areas. The three power plants impact 18 of these areas.

For additional information on the proposed rulemaking and opportunities to provide input, please go to: