In this April 21 photo released by the US Coast Guard, a fire aboard the mobile offshore drilling unit Deepwater Horizon burns 52-miles southeast of Venice, La. Helicopters, ships and an airplane searched waters off Louisiana's coast Wednesday for missing workers after an explosion and fire that left an offshore drilling platform tilting in the Gulf of Mexico. Petty Officer 2nd Class Scott Lloyd/US Coast Guard/AP
One of the columns of the badly listing P-36 oil rig, one of the world's largest, owned by Brazilian oil giant Petrobras is seen completely submerged on March 18, 2001. Petrobras/Reuters
The sun sets between oil rigs located off Huntington Beach, Calif. as seen from Sunset Beach. Robert Harbison/The Christian Science Monitor/File
Angus Kikoak is an Inuvialuit, the Inuit people of the Canadian Northwest, who is breaking into the drilling business working as a floor hand on the Akita Equtak Drilling Rig 60. The Inuvialuit-owned corporation has made employing native workers a prerequisite to gaining access to land for exploration. High oil and natural gas prices have spurred renewed activity in the Arctic as energy companies race to find new supplies. Andy Nelson/The Christian Science Monitor/File
This handout photo provided by the World Wildlife Fund and taken on Sept. 28, 2009 shows a man looking at a waxy substance found in water affected by the Montara oil rig leak in the Timor Sea. Monitoring the clean-up of a huge oil spill in pristine Australian waters could take as long as seven years, an official said on Nov. 4, as environmentalists urged a wide-ranging inquiry into the disaster. Kara Burns/HO/WWF/AFP/Newscom/File
Chevron's Discoverer Deep Seas drillship seen off the coast of Louisiana drilling for oil in the Gulf of Mexico on March 28, 2006. Nearly three football fields long, the ship appears to idle, while a 200-person crew works around the clock, preparing an adjoining oil rig. This is the kind of deepwater oil discovery once thought to be out of reach, but with improved technology and climbing global oil prices, companies are spending billions developing oil fields that will substantially boost Gulf production. Alex Brandon/AP/File
An emergency boat works to put out a fire at the Kab 121 oil platform belonging to the Mexican state-owned oil company PEMEX, in the Gulf of Mexico, on Dec. 3, 2007. After a drilling rig slammed into this production platform, leaving 21 workers dead, a total of 11,700 barrels of oil, about 420 a day, seeped into the gulf. America Rocio/AP/File
2008 Republican presidential candidate, Sen. John McCain (2nd-l.) tours the Chevron Genesis Oil Rig Platform with Joe St. Ann (l.) Offshore Installation Manager, in the Gulf of Mexico near New Orleans, La., on Aug. 19, 2008. Mary Altaffer/AP/File
The Thunder Horse oil rig, the world's largest floating oil and gas production platform, is stationed in Ingleside Texas on Feb. 26, 2005. Former Secretary of the Interior Gale Norton was among those donning hard hats and steel-toed boots for a tour of Thunder Horse, a $5 billion mass of steel rigging set to head out to mile-deep waters in the Gulf of Mexico. Owners BP PLC and ExxonMobil say Thunder Horse will drill enough petroleum each day to fuel 90 SUVs driving a million miles. Jim Sanchez/Caller-Times/AP/File
This handout picture released by Denjaka, an elite navy special forces unit, shows Indonesian Denjaka naval commandos during a simulated pre-dawn assault at a China National Offshore Oil Corp oil rig during an anti-terror exercise in the waters off Jakarta on March 3. Denjaka/Rama/HO/AFP/Newscom
An oil rig under construction floats at berth in an Astrakhan, Russia construction site. When completed the rig will be towed out into the Caspian Sea and placed. Robert Harbison/The Christian Science Monitor/File
Sitting on the side of an oil platform in the Russian Arctic with enough supplies for several days the activists protest Gazprom's plans to drill in a fragile area, the group says.
ByGabriela Baczynska, Reuters
Six activists from Greenpeace scaled Gazprom's oil platform in the Arctic early on Friday and aimed to stay there to protest against the Russian energy giant's plans to drill in a fragile area, the environmental group said.