It is no secret that the U.S. military has used the ocean as trashcan for munitions in the past. Peter discussed at the Old DSN how federal lawmakers were pressing the US Army to reveal everything it knows about a massive international program to dump chemical weapons off homeland and foreign shores. "The Army now admits that it secretly dumped 64 million pounds of nerve and mustard agents into the sea, along with 400,000 chemical-filled bombs, land mines and rockets and more than 500 tons of radioactive waste - either tossed overboard or packed into the holds of scuttled vessels." Brian pointed me to the Daily Press's in depth coverage of this whole issue. Registration is free and only takes a minute or two and is extremely worthwhile. Included at the site are maps of disposal sites (downloadable as pdfs), stories, descriptions of items dumped including nerve and musturd gas, and rather depressing pictures some are below the fold (all from Daily Press). 

Hundreds of dolphins washed ashore in Virginia and New Jersey shorelines in 1987 with burns similar to mustard gas exposure. One marine-mammal specialist suspects Army-dumped chemical weapons killed them. (Photo courtesy of the Marine Mammal Stranding Center in New Jersey)

The SS William Ralston filled with 301,000 mustard gas bombs and 1,500 1-ton canisters of Lewsite -- sinks in the Pacific off San Fransico in 1958 (Photo courtesy of the U.S. Army)

http://scienceblogs.com/deepseanews/2007/06/munitions_dumping_at_sea.php