Workers at Los Alamos National Laboratory used organic cat litter to clean up nuclear waste. The litter triggered chemical reactions that later caused a drum to burst.
Department of Energy/Flickr
A 2008 view of the leading edge of the Larsen B ice shelf, extending into the northwest part of the Weddell Sea. Huge, floating ice shelves that line the Antarctic coast help hold back sheets of ice that cover land.
Mariano Caravaca /Reuters/Landov
Interior Secretary Sally Jewell speaks in Anchorage, Alaska. The Obama administration is requiring companies that drill for oil and natural gas on federal lands to disclose chemicals used in hydraulic fracturing operations.
A platform owned by Mexico's state-run oil company Pemex is seen off the Bay of Campeche in the Gulf of Mexico. The country has recently opened up its energy sector to foreign investors.