BP spill clouds future of U.S. drilling

In this Wednesday, May 26, 2010 photo provided by the U.S. Coast Guard, the mobile offshore drilling unit Q4000 holds position directly over the damaged Deepwater Horizon blowout preventer as crews work to plug the wellhead using a technique known as "top kill." The procedure is intended to stem the flow of oil and gas and ultimately kill the well by injecting heavy drilling fluids through the blow out preventer on the seabed, down into the well. (Petty Officer 3rd Class Ann Marie Gorden / U.S. Coast Guard via AP )