Narrator: This is Science Today. What do you do when there's an oil spill at sea? Toxicologist Ron Tjeerdema of the University of California, Santa Cruz says that if the spill is miles offshore, the best response is to do nothing -- the toxic stuff will soon evaporate.

Tjeerdema: When we really have the problem is when it's moving toward shore. And then we have to decide what to do, and then you get into determining what are the coastal resources that are going to be impacted when this comes onshore.

Narrator: One of the hardest decisions is whether or not to clean off oiled animals and birds. Tjeerdema says other rescuers have learned that that's a pretty inefficient process.

Tjeerdema: Most of those that come in for cleaning tend to be too far gone to help, and so many of them die anyway. A significant number die from the stress of the cleaning process, and when you look at it from a cost basis, it's extremely expensive to clean the few that do survive. So I think there's a growing sentiment that it may not be worth it in most cases to spend the time and the effort to clean the few, or the many, seabirds and marine mammals when only a few are going to ultimately survive.

Narrator: For Science Today, I'm Steve Tokar.