They have good reason to worry. Even though BP claims otherwise, we just don't know for sure and you shouldn't just dump it anywhere (although I suspect they will, anyway):

About 35,000 bags — or 250 tons — of oily trash have been carted away from this beach, said Lt. Patrick Hanley of the Coast Guard, who is stationed at Port Fourchon. And as of Monday, more than 175,000 gallons of liquid waste — a combination of oil and water — had been sent to landfills, as had 11,276 cubic yards of solid waste, said Petty Officer Gail Dale, also of the Coast Guard, who works with at the command center in Houma.

Michael Condon, BP’s environmental unit leader, said that tests have shown that the material is not hazardous, and can safely be stored in landfills around the region that accept oil industry debris. The checklist and procedures involved, Mr. Condon said, are part of a process “we do very well and have done for a long time.”

But some local officials, environmental lawyers and residents who live near landfill sites are not convinced.

“There’s no way that isn’t toxic,” said Gladstone Jones III, a New Orleans lawyer who has spent much of his career trying to get compensation for plaintiffs he says have been harmed by exposure to toxic waste.

In fact, waste from oil exploration and production falls into a regulatory no man’s land, neither exactly benign nor toxic on its face. The compounds in oil most dangerous to human health — like benzene, a carcinogen — are volatile and tend to dissipate when crude oil reaches the ocean surface, or soon thereafter. But some toxicologists say it is impossible to know whether the toxic chemicals are entirely gone.