Huge sunken ships that were torpedoed during World War II may rest quietly on the seafloor today, but some of those wrecks still threaten to pollute American waters with oil creeping out of their tanks, according to a new report.
Thirty-six sunken vessels were flagged as potentially hazardous to U.S. coastal marine resources in a report that the National Oceanic and Atmospheric Administration (NOAA) presented to the U.S. Coast Guard this week.
Not all of the shipwrecks on the list were casualties of war. Other threats include a tanker that exploded in 1984; a barge that sank in rough seas in 1936; and two ships that went down after separate collisions in 1947 and 1952.
NOAA maintains a database of some 20,000 shipwrecks, but only a fraction of those are thought to contain oil. In 2010 Congress approved funds for the agency to develop a list of wrecks with the potential to create pollution problems that might have harmful effects on local environments and economies. [Shipwrecks Gallery: Secrets of the Deep]
To get started, the agency considered only shipwrecks of vessels built after 1891 (when the United States began using fuel oil), steel vessels, ships over 1,000 tons (900 metric tons), and all tankers. They then took into account risk factors like the amount of oil each ship was carrying as either cargo or fuel and whether or not the ship went down violently.
NOAA officials ultimately identified 36 wrecks — most of them WWII-era ships along the Atlantic and Gulf coasts — that could pose a serious pollution threat in the worst-case scenario. The report also marked 17 vessels that should be considered for further assessment and the possibility of oil removal.
But all told, the shipwreck risk isn't as bad as feared, the report indicated.
"From a national perspective, our coastlines are not littered with 'ticking time bombs' of oil, although there are definitely vessels of concern in our waters that should be assessed and monitored," the report states. "With this assessment we can put reliable bounds on the potential oil pollution threats and start to plan accordingly."
The report also said the U.S. Coast Guard should consider engaging citizen scientists and divers to help with monitoring efforts by asking them to report any possible oil sheening observed by these wreck sites.
"This report is the most comprehensive assessment to date of the potential oil pollution threats from shipwrecks in U.S. waters," Lisa Symons, resource protection coordinator for NOAA's Office of National Marine Sanctuaries, said in a statement. "Now that we have analyzed this data, the Coast Guard will be able to evaluate NOAA's recommendations and determine the most appropriate response to potential threats."