"Pennsylvania is considering new air pollution limits for diesel- and natural gas-powered engines used in Marcellus Shale development that are stricter than those that exist now but, according to eight environmental groups, not nearly as tough as they could and should be."

"The operator of three coal-fired power plants in Maryland has agreed to pay a total of $2.2 million in penalties and fix long-standing pollution problems at the landfills in Southern Maryland and Montgomery County where it disposes of the ash from those plants, according to court documents."

"GENEVA — Delegates from more than 130 nations began a final round of negotiations on Sunday that are expected to lead to the creation of the first legally binding international treaty to reduce mercury emissions."

KETTLEMAN CITY -- Maria Saucedo cried as she spoke of the two babies she has lost in Kettleman City -- one to birth defects and the other in a miscarriage. There's no proof, but she blames the toxic landscape surrounding her town. She and others who have suffered in Kettleman City say they live in a nasty soup of pollution. They make a compelling case."

"BP and its partners in the Macondo well that released an estimated 4.9 million gallons of oil over three months beginning in April 2010 should be required to inform state officials -- and the public -- of the toxic materials included in the spill, and the potential health effects of those materials, a three-judge appellate panel ruled in New Orleans on Wednesday."

"GENEVA -- Mercury pollution in the top layer of the world's oceans has doubled in the past century, part of a man-made problem that will require international cooperation to fix, the U.N.'s environment agency said Thursday."

"New national drinking water rules are expected to lead to fewer dangerous pathogens coming out of the tap. The new regulation, which was announced last month and takes effect within three years, switches focus to a type of bacteria that more accurately reflects the presence of pathogens that can make people sick."

"Utahns have choice words for the ugly, unhealthy clouds that periodically shroud its valleys in winter -- like the one we can expect to endure through Thursday."

"RALEIGH -- Conservation groups filed a lawsuit on Tuesday against the state Environmental Management Commission, Duke Energy and Progress Energy seeking the cleanup or shut-down of 14 ash pits that collect tons of waste from coal-burning power plants across the state."

"Oil-sands development is polluting nearby remote Alberta lakes with rising levels of a toxic carcinogen, refuting long-standing claims that waterway pollution in the region is largely naturally occurring, a study has found."