"We felt like we had met a very high standard of compliance," she said. "We felt like we would be done at that facility for a while."
Geoff Oldfather, a spokesman for Arizona Electric Power Cooperative, would say only that the EPA's proposal "would be expensive." The company runs the Apache Generating Station near Cochise.
The state Department of Environmental Quality and Gov. Jan Brewer have urged the EPA to withdraw its proposal and called it "not only unreasonable but unnecessary," given the EPA's previous inaction on the state's plan.
The EPA said it had proposed rejecting Arizona's plan for nitrogen oxide emissions because it did not fully address the issues raised by the agency and federal land managers when it came to cost analyses, the best available technology for controlling emissions and visibility benefits.Pollution from power plants, wildfires or controlled burns and other sources worsen the air at the Grand Canyon 90 percent of the time, the agency has said. "Yet for many visitors, the spectacular views are veiled in haze, dulling the natural beauty," the EPA said.