"California water quality regulators have asked state Attorney General Kamala Harris to consider enforcement action against the owner of an oil pipeline that ruptured near Santa Barbara in May, spilling petroleum onto beaches and the Pacific Ocean."

"A device commonly used to measure the methane that leaks from industrial sources may greatly underestimate those emissions, said an inventor of the technology that the device relies on."

"The U.S. Coast Guard was investigating a large, patchy oil sheen that appeared off the Southern California coast west of Santa Barbara on Wednesday, not far from the site of a petroleum pipeline spill in May, officials said."

"RIO DE JANEIRO — Athletes in next year's Summer Olympics here will be swimming and boating in waters so contaminated with human feces that they risk becoming violently ill and unable to compete in the games, an Associated Press investigation has found."

"Barack Obama will use all of his powers – including his veto – to defend his plan to fight climate change, the White House said, on the eve of new rules cutting carbon pollution from power plants."

"Though the amount of microcystin present in raw Lake Erie water near Toledo’s water-system intake Wednesday was double the amount detected two days earlier, city officials announced they planned to scale back testing for the toxin."

"It's late summer, and Americans are flocking to the country's national parks for some recreation and fresh air."

"WASHINGTON -- A new government rule that promises to do more to protect streams near coal mining operations entered a critical stage this week, with coal industry lobbyists and environmentalists already lining up for battle."

"A conservation group found 36 U.S. national parks had moderate or worse levels of ozone pollution in a report card released on Tuesday, with four parks in California receiving the worst grades for health effects."

"A U.S. appeals court on Tuesday mostly upheld a major federal environmental regulation requiring some states to limit pollution that contributes to unhealthy air in neighboring states."