"Two environmental groups say an unlined coal ash pond just outside of Harrodsburg, Ky., is leaking toxic contaminants into the surrounding surface and groundwater, causing a potential threat to nearby residents."

"The Obama administration is considering cutting greenhouse-gas emissions from power plants by reaching beyond the plants themselves -- an unusual approach that could run afoul of anti-pollution laws."

"Oil refineries would be required to cut emissions and begin monitoring levels of toxic air pollutants at their fence lines with neighboring communities under standards proposed Thursday by the U.S. Environmental Protection Agency."

"The Los Angeles Fire Department says a ruptured oil pipe near the suburb of Glendale has spilled about 50,000 gallons of crude oil onto streets."

"A foreign oil company convicted of polluting a Texas community's air with dangerous chemicals has gotten off easy in a criminal case that could undercut the prosecution of environmental crimes in the United States. The case revolves around Venezuelan-owned Citgo Petroleum’s decade-long violation of the federal Clean Air Act at its refinery in Corpus Christi."

"Seeking to close what a lawyer called 'serious gaps' in regulation, 64 environmental and community groups on Tuesday petitioned the Environmental Protection Agency to clamp down on toxic air emissions from oil and gas operations."

"Smog could worsen across the United States in the coming decades as climate change boosts summer temperatures and makes ozone levels more difficult to control, a new study says."

"Chemicals in water from deep underground in hydraulic fracturing wells have caused problems as they get to water treatment plants in other states. It’s a potential problem to consider as North Carolina moves closer to allowing fracking."

"A draft letter from a U.S. EPA science advisory committee recommends a tight standard for how much ozone pollution can be in the air, recommending that the lower bound of the standard should be 60 parts per billion, much lower than the current standard. But the letter notes that committee members haven't made a decision on the upper bound of the ozone standard."