"Canadian Prime Minister Stephen Harper’s frustration with U.S. President Barack Obama’s failure to approve the Keystone XL pipeline may make this installment of the North America summit, known as the “Three Amigos,” the frostiest since the annual meetings began almost a decade ago."

"The head of nuclear safety for the cleanup of the former nuclear weapons site at Hanford, Wash., was fired Tuesday after allegations she made over several years that the construction project was ignoring serious safety problems."

"Gov. Earl Ray Tomblin is urging federal health officials immediately to conduct more lab studies on the chemicals that spilled into a public water supply last month. The governor also asked the Centers for Disease Control and Prevention and its partners for guidance on long-term health monitoring for the nine counties exposed to the chemicals."

"UPPER MARLBORO, Md. — President Obama on Tuesday ordered the development of tough new fuel standards for the nation’s fleet of heavy-duty trucks as part of what aides say will be an increasingly muscular and unilateral campaign to tackle climate change through the use of the president’s executive power."