The New York Times offers some reason to think that, at the very least, the Gulf oil spill might not turn into the worst environmental disaster in U.S. history:

But on Monday, the wind was pushing the slick in the opposite direction, away from the current. The worst effects of the spill have yet to be felt. And if efforts to contain the oil are even partly successful and the weather cooperates, the worst could be avoided.

“Right now what people are fearing has not materialized,” said Edward B. Overton, professor emeritus of environmental science at Louisiana State University and an expert on oil spills. “People have the idea of an Exxon Valdez, with a gunky, smelly black tide looming over the horizon waiting to wash ashore. I do not anticipate this will happen down here unless things get a lot worse.”

Granted, a lot would have to go right here. And even if the spill doesn't take over the marshes of Louisiana or the coral reefs by the Florida Keys, it can still do a lot of damage in the ocean to sea turtles, bluefin tuna, crabs and oysters. And then there's this:

But much of this damage could be avoided if the various tactics employed by BP and government technicians pay off in the coming days. The winds are dying down and the seas are calming, allowing for renewed skimming operations and possible new controlled burns of oil on the surface. BP technicians are trying to inject dispersants deep below the surface, which could reduce the impact on aquatic life. Winds and currents could move the globs of emulsified oil away from coastal shellfish breeding grounds.

So what are those "dispersants"? That's a good question. Propublica reports that the makeup of these chemicals are being kept secret, but they may contain toxins of their own which can kill fish and wander large distances. An earlier study of the chemicals by the National Academy of Sciences found signs that the dispersed oil can collect on the seabed, get absorbed by microscopic organisms, and make its way up the food chain. Of course, that wouldn't be nearly as sensational—or photogenic—as a big oil spill, but that doesn't mean it would be an optimal outcome.