Arizona’s metal mining and manufacturing industries produced about 84.5 million pounds of toxic chemicals in 2011, a nearly 34 million pound increase from just two years earlier, the Environmental Protection Agency reported.

The Navajo Nation has reached an agreement in extending a lease for a coal-power plant that would give the tribe a substantial boost in annual payments.

Critics vow to battle costly federal plan for coal-powered plants

The edict by the U.S. Environmental Protection Agency would affect the Apache, Cholla and Coronado plants and could collectively cost Arizona utility companies as much as $1 billion.

For the most part, Arizona lawmakers appear to have stepped back from the trenches of the states’ rights issue after years of incessant fighting with the federal government.

The U.S. Environmental Protection Agency says it has exceeded its goals in assessing structures on the Navajo Nation for uranium contamination.

For seven weeks this fall, workers and scientists labored from 7:30 a.m. to 5 p.m., six days a week, digging up and hauling off thousands of cubic yards of uranium-tainted soil in Cove, Ariz., and sealing what remained.

Gov. Jan Brewer is asking the Environmental Protection Agency to reverse course on its demand that three coal-fired power plants complete a retrofit that will cost utility companies $1 billion and could mothball the plants entirely.

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.

WASHINGTON – Power plants on Navajo Nation land need more time to meet new emissions standards or they could be forced to close, throwing thousands of Navajo out of work and costing the tribe millions, an official said Wednesday.

Auto emission rules have barely taken effect and already the state wants to scrap it because it costs too much.