Ten miles out in the Gulf of Mexico, off the tip of Louisiana, the fumes become overwhelming. "See how it's all rainbow sheen there? So that's oil," says Ian MacDonald, who's guiding us in a tiny fishing boat that's being tossed around by 6-foot waves.
MacDonald is a scientist at Florida State University where he studies oil spills. This one is not a black, sticky slick, but it stretches on for miles. And here, where the murky Mississippi River dumps into the Gulf, it's been leaking for more than 14 years.