U.S. forces have been operating in that area to try to choke off Taliban and al Qaeda members fleeing to Pakistan.

CNN: Soldier's body to arrive in the U.S. Tuesday

And because the bacteria use oxygen in the water as they digest oil, scientists are concerned that process could cause an oxygen-depleted area underwater a "dead zone" that could choke off a variety of undersea life.

WSJ: Gauging Harm to Ecosystem Could Take Years