New limits on mercury and lead are causing the nation's oldest, dirtiest plants to shut down.

Dolphin for dinner? It may be more common than you think.

Guidelines for gardeners acknowledge that plants can now survive farther north.

As U.S. seeks a permanent repository, it might look to Europe for lessons.

High-flying satellite makes a crystal-clear image.

Show this to your skeptical friends.

A utility's worst nightmare takes shape in Colorado.

“I will not stand by when our competitors don’t play by the rules,” president says.

In State of the Union speech, Obama declares "an all-out, all-of-the-above strategy."

Will farmed salmon, set free, pollute their wild cousins?