By By Karen Graham Nov 1, 2015 in Environment In the past 100 years, commerce and warfare have left the coastal waters of the United States littered with thousands of sunken vessels. Even though shipwrecks are fascinating, there are now environmental concerns that need to be addressed. The NOAA Resources and UnderSea Threats (RUST) database has over 30,000 targets, including 20,000 vessels. NOAA Ships that went down in shallower waters have already been salvaged, or because they were thought to be dangerous to navigation, destroyed. And then there are the ships that sank off the continental shelf and have never been found. But of all the ships sitting on the bottom of our coastal waters, one thing is sure, they are all suffering from corrosion. The Dive teams are searching for the source of an apparent oil leak in a barge that sank in Lake Erie in the 1930s. The barge is just one of 87 shipwrecks on a federal registry developed two years ago that identifies shipwrecks with the most serious pollution threats in U.S. waters, based on a report by SS Edmund Fitzgerald underway in 1971. Greenmars Most of the wrecks on the list are located on the Atlantic Coast, torpedoed by German U-Boats during WWII. A few more can be found along the Pacific Coast and in the Gulf of Mexico just off the Florida and Louisiana shorelines. All these shipwrecks are thought to be holding oil. There are five sunken ships in the Great Lakes, including the Edmund Fitzgerald that sank in 1975 and memorialized in a song by Gordon Lightfoot. Three-fourths of the 87 shipwrecks are over 70 years old. It is difficult to estimate the damage from corrosion because the rates of corrosion are affected by varying depths, storms, currents and marine bacteria. Historical evidence has shown the oil leaks out in drips and drabs, not enough to create a full-scale environmental problem, but the threat is always there and becomes more worrying as time goes on. Scene from a video showing an old shipwreck leaking oil into the North Sea environment. Carl Dan Dijk "Our coastlines are not littered with 'ticking time bombs' of oil," said the risk assessment report released by the The U.S. Coast Guard does monitor some of the ships, but others remain a mystery. However, the biggest obstacle in monitoring and salvaging these ships is money. The cost of removing oil and other fuels from shipwrecks in the last two decades has ranged from a few million dollars to tens of millions of dollars. The money comes from the Oil Spill Liability Trust Fund, which is overseen by the Coast Guard. This fund allows for $50 million to be spent annually on emergency spills and damage assessments. Any money left over is carried over to the next year. Last year, the fund paid out $62.4 million. Jacqueline Michel, a geochemist who has done extensive research on sunken oils and assisted with spill responses, says there isn't nearly enough money available to remove all of the oil from the 87 wrecks targeted by NOAA. "It would be gone in a minute," she says. And the United States is not the only country with this problem. Shipwrecks pose an environmental problem in European waters, including the Mediterranean, Baltic, and North seas. Of the over 20,000 shipwrecks off the coastal waters of the U.S., many of the older ones were sailing or coal-fired ships and never used oil as fuel or even as cargo. More contemporary ships met their end violently, breaking up due to storms, collisions or warfare.Ships that went down in shallower waters have already been salvaged, or because they were thought to be dangerous to navigation, destroyed. And then there are the ships that sank off the continental shelf and have never been found. But of all the ships sitting on the bottom of our coastal waters, one thing is sure, they are all suffering from corrosion.The Associated Press says there are dozens of wrecked ships thought to be holding oil off our coastal waters. And as these wrecks deteriorate, corrosion will eventually lead to oil leaking from their tanks.Dive teams are searching for the source of an apparent oil leak in a barge that sank in Lake Erie in the 1930s. The barge is just one of 87 shipwrecks on a federal registry developed two years ago that identifies shipwrecks with the most serious pollution threats in U.S. waters, based on a report by Michigan Radio on Saturday.Most of the wrecks on the list are located on the Atlantic Coast, torpedoed by German U-Boats during WWII. A few more can be found along the Pacific Coast and in the Gulf of Mexico just off the Florida and Louisiana shorelines. All these shipwrecks are thought to be holding oil. There are five sunken ships in the Great Lakes, including the Edmund Fitzgerald that sank in 1975 and memorialized in a song by Gordon Lightfoot.Three-fourths of the 87 shipwrecks are over 70 years old. It is difficult to estimate the damage from corrosion because the rates of corrosion are affected by varying depths, storms, currents and marine bacteria. Historical evidence has shown the oil leaks out in drips and drabs, not enough to create a full-scale environmental problem, but the threat is always there and becomes more worrying as time goes on."Our coastlines are not littered with 'ticking time bombs' of oil," said the risk assessment report released by the National Oceanic and Atmospheric Administration in 2013. "Although there are definitely vessels of concern in our waters that should be assessed and monitored."The U.S. Coast Guard does monitor some of the ships, but others remain a mystery. However, the biggest obstacle in monitoring and salvaging these ships is money. The cost of removing oil and other fuels from shipwrecks in the last two decades has ranged from a few million dollars to tens of millions of dollars.The money comes from the Oil Spill Liability Trust Fund, which is overseen by the Coast Guard. This fund allows for $50 million to be spent annually on emergency spills and damage assessments. Any money left over is carried over to the next year. Last year, the fund paid out $62.4 million.Jacqueline Michel, a geochemist who has done extensive research on sunken oils and assisted with spill responses, says there isn't nearly enough money available to remove all of the oil from the 87 wrecks targeted by NOAA. "It would be gone in a minute," she says.And the United States is not the only country with this problem. Shipwrecks pose an environmental problem in European waters, including the Mediterranean, Baltic, and North seas. 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