A quarter-century after 10.8 million gallons of crude oil gushed from the Exxon Valdez and scarred Alaska's Prince William Sound, oil spill responders fear that another disaster looms in more remote Alaskan waters where ship traffic is on the rise, due in part to the North American energy boom.
The largest concern centers on the Arctic, where oil exploration and development is progressing in fits and starts, and Unimak Pass in the Aleutian Islands, a choke point on a major shipping route between North America and Asia. Both regions are expected to see increased traffic as summer sea ice disappears and producers of North American crude oil and coal look to export fossil fuels to Asia.
"You can't separate the two areas out, you have to look at both of them," said Leslie Peters, a project manager for the Aleutian Islands Risk Assessment. The assessment is a $3 million study of the potential oil spill threat to the region, funded by a settlement reached with the owners of a cargo ship that grounded near the Aleutian community of Unalaska in 2004 and spilled 350,000 gallons of fuel oil.
Other worrisome spots include Washington state's Puget Sound, the coast of Maine, and anywhere in the continental U.S. intersected by the web of pipelines and railways that transport crude oil from shale plays in the U.S. and tar sands in Canada, according to Gary Shigenaka, a marine biologist with the National Oceanic and Atmospheric Administration's emergency response division in Seattle.
"It is not as though we aren't worried about tanker and barge spills anymore. It's just that now we have these other direct and indirect concerns related to pipeline spills and railcar accidents," he told NBC News. In addition, the North American oil boom may lead to "increased traffic through places like Unimak Pass that don't have a history or infrastructure to support a spill response in a very good way."
Safer sailing since Valdez
The incidence of major oil spills has been reduced by a factor of 10 since the Exxon Valdez oil tanker ran aground on March 24, 1989, according to Simon Bennett, a spokesman for theInternational Chamber of Shipping, an industry trade group based in London. He says that's due to spill prevention measures that the international shipping industry put in place after the environmental catastrophe.
"The reasons for the improvements are a combination of better technical [ship] design but also stronger enforcement of the international regulations applying to ships," he told NBC News.
(Read more: )
Among the measures put in place is a congressionally mandated requirement that by 2015 all tankers in U.S. waters should have what's known as a double hull. On these ships, the oil is carried in a watertight inner hull. If a breach occurs on the outer hull, the inner hull will prevent the oil from leaking. The international shipping community adopted the standard, Bennett said.
Proof that double hulls work came in March 2009 when the Norwegian tanker SKS Satilla struck submerged hurricane debris in the Gulf of Mexico. The collision put a gash in the vessel's outer hull, but all 41 million gallons of crude remained on board until it was safely transferred, according to NOAA's spill response team.