Military Ordnance Found on U.S. Shores

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IKEA’s shelters have an average lifespan of three years.The explosive ordnance disposal team from the U.S. Army’s Aberdeen Proving Ground detonates the World War II bomb off the shore of Assateague Island, Maryland (U.S.).
Photo courtesy of Maryland Coast Dispatch.

A World War II (WWII) bomb was detonated 25 June 2013 after it washed ashore on Assateague Island National Seashore, Maryland, U.S.1 The U.S. Army Corps of Engineers surveyed the beach for two days, turning up more than 100 inert pieces of ordnance.2

On the same day a resident of Bay Head, New Jersey, U.S., located a partially buried WWII, German contact mine that was about 3 m (10 ft) from the shore.3 As a safety precaution, 15 nearby homes were evacuated, and the U.S. Coast Guard prevented boats from entering the area. Assateague Island and Bay Head were closed while the areas were combed with radar equipment, re-opening after explosive ordnance disposal teams destroyed the munitions and the areas were deemed safe.1,4

This is not the first time ordnance has washed up on U.S. shores—park rangers say it is “surprisingly common.”5 Ordnance has washed ashore in at least 11 coastline states. During the world wars, the U.S. military tested explosives at Aberdeen Proving Ground, Maryland; Sandy Hook Proving Ground, New Jersey; and proving grounds in Arizona, California, Illinois, Indiana, Massachusetts and Ohio.6

The military discarded munitions in the Gulf of Mexico and Atlantic and Pacific Oceans, mostly from the years 1943–1947. Dumping sites for unused bombs were only 97 to 161 km (60 to 100 mi) offshore. At the time, many countries practiced offshore dumping of munitions.

Army records of U.S. dump sites are vague, missing or were destroyed.7 The Defense Environmental Programs 2009 Annual Report to Congress listed military munition sea disposal locations in the U.S. from 1917–1970: 26 dump sites in the northeast, 17 in the southeast, 9 in the west, and 20 near Alaska and Hawaii.8 The U.S. Department of Defense prohibited the dumping of unexploded ordnance in U.S. coastal waters in 1970. Congress passed the Marine Protection, Research and Sanctuaries Act in 1972, banning the marine disposal of any material that would unreasonably harm humans or the environment.9

According to combined research by Texas A&M University oceanographers William Bryant and Niall Slowey, and researcher Mike Kemp, more than 31 million pounds (14,061 tonnes) of bombs are dispersed in the Gulf of Mexico and along the coasts of at least 16 U.S. states.9,10 While “potentially dangerous,” not all ordnance are highly explosive; National Park Service (NPS) files at Assateague Island assert that the test rockets buried off the coast “only carried sufficient explosives to detonate a smoke bomb”4

Munitions are shifting closer to the shoreline as Maryland and New Jersey experience soil erosion, which constantly changes the landscape along the coast. Therefore more ordnance will likely be discovered in the future.2,11 c



  1. “Assateague Island evacuated after WWII ordnance found.” ABC 2 News, 25 June 2013. Accessed 22 July 2013.
  2. “Assateague beaches reopen after sweep for ordnance.” Virginian-Pilot, 29 June 2013. Accessed 22 July 2013.
  3. Sahn, Michelle. “Possible WWII-era mine found on Bay Head beach blown up by Navy divers.” Daily Record, 27 June 2013. Accessed 22 July 2013.
  4. Soper, Shawn. “Assateague’s History Rich with War Activity; Military Cache Discovery Not Unusual for Island.” Maryland Coast Dispatch, 5 July 2013. Accessed 22 July 2013.
  5. “Assateague Beach Closed After WWII Ordnance Found." CBS News, 25 June 2013.
  6. “156.11 Records of Ordnance Proving Grounds.” National Archives. Accessed 22 July 2013.
  7. Bull, John. “House Takes on Army’s Offshore Dumping.” The Daily Press, 11 May 2006. Accessed 24 July 2013.
  8. “Sea Disposal of Military Munitions.” Defense Environmental Programs Annual Report to Congress, 2009. Accessed 7 August 2013.
  9. Barrie, Allison. “Millions of unexploded bombs lie off US coast, researchers say.” Fox News, 8 October 2012. Accessed 22 July 2013.
  10. “Bombs in Gulf of Mexico Pose Big Problems.” Geosciences News. Accessed 22 July 2013.
  11. “Soil Erosion and Sediment Control Act.” State of New Jersey Department of Agriculture. Accessed 22 July 2013.