Oil swirls in a flooded gravel pit in Lockwood, Mont. after a pipeline break early Saturday, July 2, 2011. The ExxonMobil pipeline that runs under the Yellowstone River near Billings in south-central Montana ruptured and dumped an unknown amount of oil into the waterway, prompting temporary evacuations along the river. (AP Photo/The Billings Gazette, Larry Mayer)
