Sparse attendance at a 1993 reunion prompted Alderson, a retired Navy Reserve lieutenant commander, to speak out. He learned that more than half of the 500 or so crew members who took part in the tests were either dead or suffering from cancer, respiratory problems or other ailments. Alderson wondered whether his own skin cancers, allergies and chronic fatigue were linked to those tests or were simply the result of aging.
"I was told by my bosses and the docs and so forth that if you follow these routines ... you're going to be OK," Alderson, 74, said in an interview. "We did exactly as told. And we're finding out now that we're sick."
Alderson and other witnesses were to testify Thursday before a House Veterans Affairs panel considering legislation that would require more Pentagon disclosure about the Cold War-era germ and chemical weapons testing and extend benefits to veterans who participated in them. A similar bill is scheduled for a vote in the Senate Veterans Affairs Committee later this month.
Lawmakers say the legislation is needed because the Pentagon has not acknowledged a link between the tests and health problems, which has made it difficult for veterans to get health coverage. Pentagon officials don't rule out a health link but say it's tough to prove.
"We cannot say that this exposure 40 years ago had absolutely no health effect," said Dr. Michael Kilpatrick, the Pentagon's deputy director for force health protection and readiness. "I don't think any physician would risk saying that. Because how do you prove that that's the case?"
A similar debate took place around Agent Orange, the chemical defoliant used by U.S. forces in Vietnam that was linked to cancer and other ailments in those exposed to it. At Congress' insistence in the late 1980s, the government extended benefits to veterans and their children suffering from Agent Orange-related diseases.
The bill under consideration Thursday, by Reps. Mike Thompson, D-Calif., and Denny Rehberg, R-Mont., is patterned after the Agent Orange legislation.
In testimony prepared for the hearing, obtained in advance by The Associated Press, Bradley Mayes, the Veterans Affairs Department's director of compensation and pensions, calls the legislation unnecessary, "due to the lack of credible scientific and medical evidence that adequately demonstrates any statistically significant correlation" between the tests and participants' diseases.
Last year, the Institute of Medicine, which advises the government on medical and health matters, found no specific health effects as a result of Project SHAD - Shipboard Hazard and Defense. Alderson, Thompson and others argue that the report was shoddily done and left out key information.
"It started out being a secret project and turned into being a CYA type of thing, you know, cover your rear end. And an embarrassment," Thompson said of the tests and their aftermath.
Action from Congress would be a relief to Alderson, who lives modestly in Ferndale, Calif., among the redwoods north of San Francisco. His home is decorated with stacks of documents about his days in charge of a fleet of five light tugboats that were sprayed with biological agents and cleaned afterward with solvents, some of which now are considered carcinogenic.
During the tests, conducted amid Cold War concerns about the Soviet Union's weapons capabilities, the military tested germs such as bacteria that could cause tularemia and Q fever, serious diseases more commonly found in animals. Also used were nonlethal simulated agents, including E. coli, now known to pose health dangers.
Test participants were given experimental vaccines but weren't told of any risks, only that the shots were a protective measure, Alderson said. Project SHAD also involved spraying service members aboard large Navy ships.
Kilpatrick acknowledges that some participants weren't fully informed about the project they were part of but says safety precautions taken then were appropriate for the time.
Alderson said he has pressed the Pentagon for answers about the secret tests because he feels he owes that to the crews he commanded.
In 1995, Alderson got a copy of a letter that the Navy's medicine and surgery bureau sent to his then-congressman, Rep. Frank Riggs, stating they had no records of Project SHAD. Six years later, after continued questioning from Riggs and Thompson, the Pentagon began to publicly release details on the existence of Project SHAD and its umbrella program, Project 112, which involved distribution of nonlethal bacteria and occasionally real chemical or biological weapons.
The Defense Department now says 6,440 service members took part in 50 tests under Project 112 between 1962 and 1973, including open-air tests above a half-dozen U.S. states.