Barge piled high with mustard gas

A barge is loaded with mustard gas canisters that later were thrown somewhere into the Atlantic in 1964. (Photo courtesy of the U.S. Army)

Those countries include New Zealand, China, the former Soviet Union and unidentified "Latin American countries."

The United States used parts of Panama as chemical weapons bombing ranges for years. Other National Archives records detail two shipments of unidentified chemical weapons, totaling 20,000 pounds, in 1953 and 1954 from the United States to Fort Amador, Panama.

The Army said it informed the governments of those five unidentified countries in recent years of the dangers lurking off their coasts. But, it said, it was asked by those governments not to release the information to the public.

Two summers ago, researchers for the New Zealand government searched U.S. government records at the National Archives, seeking information on chemical weapons ocean dumpsites, archivist Tim Nenninger said.

Harigel said residents of those unidentified countries should be told by someone - either their governments or the Army - of the potential dangers.

"Whether or not anything can be done at this point, the people there deserve to know," he said. "The danger increases with time. The shells are more and more corroding. The fishermen can easily get this stuff into their nets and get seriously hurt."

Scientists have determined that mustard agent damages DNA, causes cancer and survives for at least five years on the ocean floor in a concentrated gel. Nerve gas lasts at least six weeks in seawater, killing every organism it touches before breaking down into its nonlethal component chemicals.

Chemical-filled munitions now on seabeds are slowly leaking, and more surely will as years pass - depending on the depth of the water, the thickness of the containers and water temperature, according to a 2004 study by Jiri Matousek, a Czech scientist.

The hazard of leaking shells likely will last for "another tens to hundreds of years," he concluded. "It is also without doubt that long-term monitoring at areas of concern is needed as a categorical imperative."

The problem is so bad in the Baltic Sea, Denmark has covered parts of some shallow-water dumpsites with concrete to contain leakage.

OTHER COUNTRIES WEREN'T TOLD

The Army has known for decades of its overseas chemical weapons dumps, yet it left other governments to find and deal with the problem on their own.

Japan's problems from U.S. chemical weapons dumping did not come to light until a government inquiry in 1973, after more than 85 fishermen were injured by chemical warfare agents dumped by either U.S. occupation forces or the Japanese military at the close of World War II.

It wasn't until 2003 that Australia found on its own that the Army dumped more than 60 million pounds of chemical weapons off Brisbane. Australia pinpointed precise quantities and nautical coordinates.

The Australian government has posted the area off-limits to mariners and released a well-publicized report on its findings.

The Canadian Department of National Defence has worked for three years to identify offshore chemical weapons dumpsites created by either the U.S. or Canadian military. Three have been found, and the Canadians think the United States might have created one of them.

The well-publicized Warfare Agent Disposal project began after a Halifax, Nova Scotia-area antiques dealer named Myles Kehoe learned that the Canadian military moved some of its post-World War II chemical munitions through Nova Scotia for disposal. When his fisherman father remembered hearing that the ordnance was loaded onto ships and dumped at sea somewhere, alarm bells went off in Kehoe's head.

"He laughed about it," Kehoe said. "They did it all the time, he said."

At Kehoe's insistent prodding, the Canadians are researching about 1,200 other underwater locations their records show might be ordnance dumps.

The Canadian government thinks the United States might have jettisoned chemical weapons about 100 miles off Vancouver Island in British Columbia, north of Washington state. The Army said it had no record that was done but wouldn't rule it out.