The U.S. Environmental Protection Agency is proposing to approve Arizona's plan to control sulfur dioxide and soot at three power plants in the state.
EPA officials also are proposing additional pollution controls for nitrogen oxide at those plants in an effort to improve visibility at 18 national parks and wilderness areas in Arizona.
More than 11 million people visit national parks in Arizona every year.
Arizona wants to control emissions of sulfur dioxide and coarse particles from the older boilers at three power plants located in eastern Arizona.
The EPA is proposing a federal plan to limit nitrogen oxides emissions at these same three plants - the Cholla Power Plant, the Apache Generating Station and the Coronado Generating Station.
The deadline for final EPA action is Nov. 15.
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