"An environmental group threatened to sue two of the nation's biggest rail owners Tuesday under a novel legal theory that would classify diesel exhaust as hazardous waste."

"In a win for the coal industry, a House committee approved a bill Tuesday that would prevent federal regulation of coal ash as hazardous waste."

"Researchers found 'significantly higher' rates of birth defects in areas with mountaintop removal mines than in non-mining regions in central Appalachia, according to a study released Tuesday."

"Exposure to chemicals early in life may alter how breast tissue develops and raise the risks of breast cancer and lactation problems later in life, scientists concluded in a report published Wednesday. The scientists are urging federal officials to add new tests for industrial chemicals and pesticides to identify ones that might disrupt breast development."

"Crews have made significant progress attacking three major wildfires in Arizona, but fire danger across the Southwest will remain for weeks to come until seasonal rains arrive."

"Steps to boost atomic safety after Japan's Fukushima accident must be 'cost-effective,' an industry body said on Tuesday, a day after the UN nuclear chief suggested power firms could help pay for expanded safety checks."

"The Environmental Protection Agency said on Tuesday it has extended the comment timeline by 30 days on a draft rule on reducing mercury emissions and other toxic pollution from power plants but left the target for finalization of the rule unchanged."