"DENVER -- Authorities are investigating after construction crews discovered a problem with a liquid gas pipeline that allowed a carcinogen to seep into the ground near a large creek that feeds into the Colorado River."

"WASHINGTON -- The Environmental Protection Agency's latest proposed tightening of limits on sulfur in gasoline, and its previous rules, will most likely have the perverse consequence of retarding the development of cars running on batteries, advanced biofuels or hydrogen -- all promising but expensive technologies that have not become mass-market products."

"GRANTS PASS, Ore. -- The last partner has dropped out of a proposal to ship coal from Montana and Wyoming to Asia through Oregon's Port of Coos Bay, port officials announced Monday."

"SPRINGFIELD, Ill. -- Dominion Energy has agreed to pay a $3.4 million civil penalty and spend $9.75 million on environmental mitigation projects to resolve Clean Air Act violations at coal-fired power plants in three states."

"Tesla sold more of its electric cars than expected in the first three months of the year, and it adjusts its first-quarter guidance to 'full profitability.'"

"These are good times for Libbey, a 125-year-old American glassmaker that nearly went bankrupt four years ago. The company’s shares have risen to almost $20 from below $1, sales of its tableware are at a record high, and its energy-intensive factories saved more than $5 million in 2012 as natural gas prices fell."

"MAYFLOWER, Ark. -- An ExxonMobil pipeline carrying tar sands oil from Canada broke open in Arkansas on Friday, spilling thousands of gallons of black diluted bitumen into residential streets outside Little Rock and forcing the evacuation of 22 homes."

"Despite some lingering anger over wood-burning rules, Bay Area air quality officials say a five-year burn ban has paid off for the region's 7 million residents."

"WRIGHT, Wyo. -- In Wyoming, folks call it the 'No Elk' plant, an $800 million project that -- once finished -- was meant to supply coal-fired power to 100,000 homes and support dozens of full-time jobs on the rolling prairie of northeast Wyoming."

"Exxon Mobil was working to clean up thousands of barrels of oil in Mayflower, Arkansas, after a pipeline carrying heavy Canadian crude ruptured, a major spill likely to stoke debate over transporting Canada's oil to the United States."