Spills and transportation

"The public doesn’t have a clear idea of how much oil is moved every day," said Potter. "The amount spilled is miniscule, compared to the amount that is transported," he said.

The industry now has a great track record, said API’s Penniman. "Back in the 1880s, we would have had a pretty good chance of ruining the world," she said, but technology and safety regulations are now significantly improved.

Today, according to the Mineral Management Service, of the billions of oil transported in U.S. water, 0.001 percent is spilled. Far more oil seeps naturally into the sea, reports the National Research Council (NRC). According to the NRC's most recent analysis, almost half of oceanic oil worldwide arises from natural processes. Oil spills contribute about 12 percent.

Even so, says Clusen, there are 300 to 500 spills every year, a number which will grow with increased production.

"And once you have a spill, you are pretty much screwed," NOAA's Short said. That's because oil spreads on water at a rate of one-half a football field per second. Recovery can take decades.

After 20 years of natural weathering, Prince William Sound — the area affected by the Exxon-Valdez spill — appears completely recovered to the casual observer, said Short, but animals high up on the food chain are just now starting to re-colonize.