Children play on a Nigerian oil-flow station in 2007. Nigeria, a major oil source for the United States, is riddled with ancient pipes and constant spills. That, plus the geopolitical challenges involved, is why much of Nigeria's crude is the kind of "tough oil" that author Michael Klare describes. George Osodi/AP hide caption

itoggle caption George Osodi/AP

Plaquemines Parish coastal zone director P.J. Hahn lifts an oil-covered pelican, which was stuck in oil at Queen Bess Island in Barataria Bay, just off the Gulf of Mexico, in early June. Gerald Herbert/AP Photo hide caption

itoggle caption Gerald Herbert/AP Photo

In this photo illustration, bottles of Avandia diabetes medication are seen at Jack's Pharmacy on May 21, 2007, in San Anselmo, Calif. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images

Fallon's brain (on the right) has dark patches in the orbital cortex, the area just behind the eyes. This is the area that Fallon and other scientists say is involved with ethical behavior, moral decision-making and impulse control. The normal scan on the left is his son's. Courtesy of Jim Fallon hide caption

itoggle caption Courtesy of Jim Fallon

The looming storm could postpone BP's plans to double the amount of oil they capture from the spill. Here, a boat uses a boom and absorbent material to soak up oil on the surface of the water near Grand Isle, La., on Monday. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

Mary VanDam pours coffee for patron Jim Brumm at Mr. B's Pancake House in Laketon Township, Mich. Cory Morse/Muskegon Chronicle via AP hide caption

itoggle caption Cory Morse/Muskegon Chronicle via AP

Oil-soaked booms sit on top of a marsh in Barataria Bay. Brian Naylor/NPR hide caption

itoggle caption Brian Naylor/NPR

A shrimp-trawler gets a high-powered spray wash after spending a day skimming oil in the Gulf of Mexico. The Coast Guard has set up dozens of offshore decontamination stations like this one south of Mobile Bay. Debbie Elliot/NPR hide caption

itoggle caption Debbie Elliot/NPR