In the summer of 2004, a clam-dredging operation off New Jersey pulled up an old artillery shell.

The long-submerged World War I-era explosive was filled with a black tarlike substance.

Bomb disposal technicians from Dover Air Force Base, Del., were brought in to dismantle it. Three of them were injured - one hospitalized with large pus-filled blisters on an arm and hand.

The shell was filled with mustard gas in solid form.

What was long feared by the few military officials in the know had come to pass: Chemical weapons that the Army dumped at sea decades ago finally ended up on shore in the United States.

It's long been known that some chemical weapons went into the ocean, but records obtained by the Daily Press show that the previously classified weapons-dumping program was far more extensive than ever suspected.

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.

A Daily Press investigation also found:

These weapons of mass destruction virtually ring the country, concealed off at least 11 states - six on the East Coast, two on the Gulf Coast, California, Hawaii and Alaska. Few, if any, state officials have been informed of their existence.

The chemical agents could pose a hazard for generations. The Army has examined only a few of its 26 dump zones and none in the past 30 years.

The Army can't say exactly where all the weapons were dumped from World War II to 1970. Army records are sketchy, missing or were destroyed.

More dumpsites likely exist. The Army hasn't reviewed World War I-era records, when ocean dumping of chemical weapons was common.

"We do not claim to know where they all are," said William Brankowitz, a deputy project manager in the Army Chemical Materials Agency and a leading authority on the Army's chemical weapons dumping.

"We don't want to be cavalier at all and say this stuff was exposed to water and is OK. It can last for a very, very long time."

A drop of nerve agent can kill within a minute. When released in the ocean, it lasts up to six weeks, killing every organism it touches before breaking down into its nonlethal chemical components.

Mustard gas can be fatal. When exposed to seawater, it forms a concentrated, encrusted gel that lasts for at least five years, rolling around on the ocean floor, killing or contaminating sea life.

Sea-dumped chemical weapons might be slowly leaking from decades of saltwater corrosion, resulting in a time-delayed release of deadly chemicals over the next 100 years and an unforeseeable environmental effect. Steel corrodes at different rates, depending on the water depth, ocean temperature and thickness of the shells.

That was the conclusion of Norwegian scientists who in 2002 examined chemical weapons dumped off Norway after World War II by the U.S. and British militaries.

Overseas, more than 200 fishermen over the years have been burned by mustard gas pulled on deck. A fisherman in Hawaii was burned in 1976, when he brought up an Army-dumped mortar round full of mustard gas.