Clusters of bad reactions to the vaccine seem to have occurred on particular bases. Many of the ailments reported by airmen at these bases were similar to those seen after the Gulf War -- severe headaches or joint pain, chronic fatigue, thyroid problems. The anthrax shots were administered to about 180,000 Gulf War-era vets, and some of them have blamed the shots for Gulf War Syndrome.

Some opponents of the mandatory program are claiming that the military secretly put squalene, a fatty substance that has been widely studied as an immune system booster, into some of the anthrax vaccines. Squalene was detected in vaccine tests earlier this year, but in quantities that are probably too minute to be medically significant, and certainly too small to have been intentional. But because the Pentagon initially denied that the shots contained any squalene, opponents of the program seized upon the discrepancy as support for their claims -- even though there's no proof that the substance can cause this type of adverse reaction.

Trust in the Pentagon program has been undermined by repeated shutdowns and fines at the Lansing, Mich., factory, owned partly by senior retired military officers, that produces all the anthrax vaccine. The FDA, which ordered the sanctions, has cited manufacturing problems that included bacterial contamination of a few vaccine lots. None of the known contaminated batches were given to soldiers, however, and the contamination would not be expected to cause the type of autoimmune reactions that have been reported.

Whether or not these mysterious ailments can be legitimately linked to the vaccine, reports of reactions have had a dramatic impact. Pilot walkouts occurred at the Air National Guard units at Fort Wayne, Ind., and Battle Creek, Mich., according to pilots from those units who have testified in Congress, after people at those bases got sick during the vaccination series.

At Dover Air Base, where C-5s lumber out over the salt marshes and the Delaware Bay en route to the world's hot spots, 50 of the 120 pilots in the base's two reserve units quit rather than be vaccinated against anthrax last year, according to Lt. Col. Jay Lacklen, chief pilot of the base's 326th Airlift Squadron.

In January 1999, after the first round of shots at Dover, one pilot developed vertigo; another got severe arthritis; and a loadmaster -- the person in charge of loading the plane -- was diagnosed with lupus, an autoimmune disease, says Lacklen, 41. He attributes a nagging medical problem of his own -- osteoarthritis of the hands -- to the vaccinations he received.

"The airline guys [commercial pilots also flying in the reserves] took one look at these people and said, 'I'm out of here,'" says Lacklen, who stresses that he's not speaking in an official capacity.

Maj. Sonnie Bates, an active-duty pilot, felt he had entered some kind of twilight zone when he transferred to Dover from a base in Texas last August.

"Here was this group of pilots, who are usually a healthy bunch, and they were all sick with this stuff no one had heard of," he says. One evening before leaving work, Bates grabbed a squadron sick list known as the DNIF (as in "duties not to include flying"), took it home and started calling everyone on it.

"All 15 had had similar reactions after the third or fourth shot," says Bates' wife, Roxane, who has become an activist in the anti-vaccine campaign. "After he noticed all these weird illnesses, we definitely knew something was wrong."

Bates took it upon himself to raise the issue with the base commander. When Bates refused to get the vaccine series himself, the Air Force announced court martial proceedings. Eventually, the charges were dropped, but Bates lost his pension and was ordered to pay $9,000 in fines, he says. Now he trains pilots at a flight school in Wilmington, Del.

He mourns his former life. "There will never be a job that can replace what I was doing," Bates says.

Maj. Frank Smolinsky, spokesman for the Air Force on the Dover base, said that 115 of the 1,838 airmen who got the shots have reported bad reactions. However, few of those reactions were debilitating, and none of the serious conditions that did occur has been clearly linked to the vaccine, he said. But senior airman Cathy Milhoan, spokeswoman for the reserve unit on the base, acknowledges that anthrax concerns hurt staffing. Congress authorizes 116 pilots for the unit, but 55 left in fiscal 2000, she says -- and 22 of those positions have still not been filled. "There is no question there were members of the wing who left the reserve in response to the anthrax vaccine," she says. "Morale was affected by the controversy." She adds, however, that those who remain have put the controversy behind them.

At the time, though, the Dover uprising made waves. When Savoie and Hechtl, who is a Southwest Airlines pilot, heard from their friends about the situation at Dover, they made up their minds to refuse the shots. Their commander was not sympathetic.

"We got blank stares from our commander and a brochure saying the shots were safe," Hechtl said, speaking on the phone from his home. Local commanders, he and other pilots said, have been forced to pass along the Pentagon's damn-the-torpedoes insistence that the program continue.

"What we were saying was, 'Guys, can we stop flying this plane into the side of the mountain?'" says Savoie. "That's what you do in the cockpit. If something's going wrong you stop, take a timeout and work out the situation. But they were unwilling to do that."

Savoie eventually became pregnant and in September gave birth to twins that the flying couple named after two favorite planes -- Hunter, a boy, and Piper, a girl. Although Hechtl ended up having to leave the service just months before completing his 20th year, the new family members were all the vindication they needed.

"I ended up having twins," Ramona Savoie says, "and they're perfect."