"States are taking the lead with studying levels of radon in drinking water and air even as federal regulators lag, as a coincidence of geology and population density leaves some more at risk than others of suffering from the naturally occurring radioactive [contaminant]."

"A nascent technology, tidal power is destined to remain a niche player in the United States' energy portfolio. But the low-carbon energy source has one advantage over wind and solar: It's as dependable as the moon's phases. Investors and public utilities are taking notice."

"A black sealant sprayed on parking lots, driveways and playgrounds turns out to be the largest contributor to the rise of a toxic pollutant in urban lakes and reservoirs across America, according to a new U.S. Geological Survey study."

"The Obama administration on Wednesday reversed its plans to expand offshore drilling along the Atlantic coast and in the eastern Gulf of Mexico in a retreat prompted by last summer's oil spill."

"The water in almost 15,000 D.C. homes that received repairs during a massive effort to remove lead pipes may still be contaminated by dangerous levels of the metal, according to a report released Wednesday by the Centers for Disease Control and Prevention."

"It took a little muscle flexing, tough talk and a few threats, but the Environmental Protection Agency got what it wanted Monday: Most states in the Chesapeake Bay region submitted detailed plans to reduce the bay's pollution diet as part of a more aggressive effort to nurse its sickly waters back to good health."

"Secretary of the Interior Ken Salazar announced a broad-based initiative on Tuesday aimed at accelerating the development of offshore wind power projects on the Outer Continental Shelf along the nation’s Atlantic coast."