But now, after seven years of inquiries from veterans, Congress and the Department of Veterans Affairs, the Pentagon has confirmed that thousands of sailors were present during a decadelong series of classified tests to determine the vulnerability of U.S. warships to attack by chemical and biological warfare.

In a series of "fact sheets" given to veterans' hospitals and organizations last month without wider public notice, the Pentagon acknowledged that some of the tests involved spraying live biological weapons over U.S. ships, including Alderson's tugs. Pentagon officials say that nerve agents such as sarin and VX gas also were used, but they refuse to disclose where, when and how.

Other tests involved exposure to "simulants," relatively harmless microbes and chemical markers used as stand-ins for a potentially deadly biological agent that resonates so powerfully today: anthrax. In all, more than a dozen ships were used, in both the Pacific and Atlantic, from 1960 to 1970. Involvement was brief for some ships and crews. For others, it was a full-time assignment lasting years.

In the tests, Marine attack bombers sprayed either simulants or live biological agents. Then the ships sailed through the resulting cloud and collected air samples. In some tests, caged monkeys were placed on deck and later tested to determine whether they had inhaled the material.

In the "hot tests," involving live biological warfare agents, the sailors took shelter in compartments rigged with positive-pressure ventilation designed to prevent the test material from infiltrating the ships. Other precautions included inoculations for rabbit fever and Q fever, two of the illnesses caused by the biological weapons employed, Pasteurella tularensis and Coxiella burnetti.

"The crews who participated ... were not test subjects, but test conductors," according to the fact sheets.

The Pentagon says no health problems have been linked to the tests, but the veterans say no one has ever looked. A dozen test veterans reached by The Courant in recent weeks, including a former medical services officer, say they never were examined for exposure to the test material in the 1960s or monitored in later years.

"I've had some concerns, respiratory problems like the others," said Norman LaChapelle, the former medical officer. "You go to the VA, a good physician will ask you, `What were you exposed to? What was your work?' Most of us until now couldn't say."

One former tug skipper has cancer of the esophagus. Another officer died after developing fibrous growths in his lungs. Dozens of others have varying degrees of respiratory problems, Alderson and others said. One old skipper, who did not want to be quoted by name, said that he collapsed and was critically ill for 18 days shortly after his Pacific service.

Ironically, the veterans say they are more concerned about the risks posed by the powerful cleansing agents used to decontaminate their ships than they are about the biological warfare agents. Some of the cleansing agents are now suspected of causing cancer.

The recently released fact sheets detail only three series of tests, conducted in 1963 and 1965 under the code names "Autumn Gold," "Shady Grove" and "Copper Head." They are only a fraction of the tests conducted as part of Shad, an acronym for "shipboard hazard and defense."

The three fact sheets are three pages each. They represent nearly a year's work searching archives and synthesizing records by a team led by Dee Dodson Morris, a chemical weapons expert who holds a position meant to underscore the Pentagon's new openness about chemical and biological warfare. Her title is "director of lessons learned."

The post was created after Persian Gulf War veterans spent a frustrating decade seeking information about chemical and biological weapons released by the destruction of Iraqi munitions. The experience has left many doubting the Pentagon's ability or willingness to fully investigate Project Shad.

Morris' fact sheets describe how the tests were supposed to be carried out. Since her team interviewed no veterans, even though Alderson and others offered to share their recollections, they do not claim to be a historical record of what actually happened.

"The fact that the military is investigating, it doesn't breed confidence. The military tends to downplay its involvement with radiation, with biological warfare and chemical warfare," said U.S. Rep. Christopher Shays, R-4th District. "The military does not have a very good record when it comes to examining itself. Its past record of candid review, it's just not there."

Secrets And Seasickness

LaChapelle helped oversee Project Shad from the "mother ship," USS Granville S. Hall. It was a converted Liberty ship with a mysterious past: In the 1950s, rigged with remote-control steering, it was sent into the atomic fallout from nuclear tests.

Years later, the Hall's crew members joked about setting off the radiation alarms every time they sailed into Pearl Harbor.

"Every time we pulled into Pearl, it was as if we were a spook. We were looked on as if we were orphans in the view of the `real Navy' or combat Navy," LaChapelle said.

To test simulants, the Hall and the accompanying fleet of tugs sailed only 60 miles off the island of Oahu. For the hot tests, they traveled 800 miles to Johnston Island, a remote atoll controlled by the Army's chemical warfare program. It was a rough trip for the tugs. Designed for sheltered waters, they pitched and rolled, as much as a stomach-churning 60 degrees.

"You had to be there to see it. Those tugs were just corks. There was no way to get a good night's sleep on those things," LaChapelle said.

Even the rhesus monkeys got seasick.

"And a seasick monkey is a pissed-off monkey," Alderson said. The 8-pound creatures frequently escaped, climbing the radio mast. They practiced their own form of biological warfare, defecating and urinating on the sailors assigned to recapture them.

The tests almost always were done at night, when the air was calm. An A-4B Skyhawk would take off from Johnston, afterburner roaring. Sometimes, the sailors could see the cloud falling from the sky, settling over the decks of the tugs.

When instruments showed that the cloud had dissipated, a crewman in a protective suit would decontaminate, washing down the ship with seawater and cleansers. The monkeys were sent to the Hall to be killed and autopsied - and the results of those tests are still secret.

Secrecy was paramount, especially when the crews returned to Pearl. J.B. Stone, a radioman assigned to the Hall in 1967 and 1968, said, "Guys who got drunk and blathered in a bar in Honolulu would disappear," reassigned to less-sensitive work.

The only tests known to take place in the Atlantic, "Copper Head," involved only simulated biological agents, according to the fact sheets. The Navy provided a destroyer, the USS Power. Its crew was told nothing - only that it was to steam from Florida to Newfoundland in January, one of its more unpopular deployments.

"They wanted cold-weather testing. They got it. The winds were horrible," said Larry Ginter of Fort Scott, Kan., then a petty officer. He remembers a special crew that came aboard. "They told me they were testing air currents and the air tightness of the ship."

Homer Tack Jr., a torpedo man from Butler, Pa., recalls conducting perhaps four tests in January and February of 1965.

"We'd go to sea. The jets would fly overhead and spray. We'd get wet. We all asked what went on. They said nothing," Tack said. He added, "I told my family for 30 years that someday this was going to hit the news."

A Belated Disclosure

Alderson started asking the Pentagon in 1994 to open its files and provide Veterans Affairs with enough data to evaluate what he and others believe is a rash of chronic respiratory illness among veterans of Project Shad. He was no crank. At the time, he was the chief executive officer of the marine district that manages the port of Humboldt Bay, Calif. Even with the help of a congressman, he got nowhere.

A book published in 1999, "The Biology of Doom," described some of Project Shad. Then CBS News aired two stories about the secret tests in early 2000. Officials say that was the impetus for the disclosures about "Shady Grove," "Autumn Gold" and "Copper Head."

Pat Eddington of the Vietnam Veterans of America said that his organization was "appalled" the experiments were ever conducted and that it took 40 years for the Pentagon to acknowledge them.

But Alderson and some of the other veterans, while frustrated at the military's slow response to their requests for information, said they are proud of their service and defend the necessity of the testing.

"It was a highly motivated crew," said LaChapelle, now the administrator of public health for Memphis and Shelby County, Tenn. "We still feel like that. We were doing an important job for the Navy and the Department of Defense."

He said he does not need to be reminded that biowar research was a real-world concern during the Cold War - or now. Today, as a public health administrator, he is in charge of investigating reports of anthrax terrorism.