Thousands of U.S. sailors were used as unwitting guinea pigs in secret germ-warfare experiments, according to a Cold War file. It is one file the military would like to leave gathering dust in some remote corner of the Pentagon.

News Correspondent Vince Gonzales reports in part two of his exclusive investigation that even after decades, some vital questions still demand answers.

As a once-secret Pentagon film shows, during germ warfare tests in the 1960s U.S. sailors were repeatedly sprayed with materials the military considered safe.

Robert Bates is just one of the former sailors with questions about the tests.

According to the Pentagon film, "Since BG is harmless, protective clothing and equipment were not required." BG, a common bacterium, was sprayed on the sailors because it is similar to the deadly anthrax germ. In some tests a fluorescent compound called Zinc Cadmium Sulfide also was sprayed. The Pentagon declined to do an on-camera interview, but tells CBS News, "We have no medical evidence that people suffered adverse health effects as a result of these tests." But how can the government know for sure? The sailors say they received no medical follow-up. And to this day, no one from the military has contacted them about the tests. Secret Experiments Read Part I of the investigation by Vince Gonzales.

Jim Druckemiller was a medical corpsman on the USS Power when it was sprayed nine times.

"We did have an upsurge of upper respiratory tract infections, colds, sore throats, that sort of thing," says Druckemiller. He's been hospitalized with pneumonia several times and has chronic respiratory illnesses. He says, "The seed of doubt is there." He and others have a range of health conditions -- chronic pneumonia, sterility, skin rashes, allergies, kidney problems -- and wonder if they are tied to the tests. "Ever since then I've always...I've had sore throats that are absolutely horrible and I've always wondered if that stuff didn't contribute to it," says George Arnold who served on the USS Navarro. In large doses, and in rare cases, BG and related bacteria can cause pneumonia, allergic reactions, nausea and vomiting. Twenty-four hours after the USS Carpenter was sprayed, ship logs show two crewmen taken ashore with "stomach cramps and vomiting." "From te perspective of the 1990s and 2000 -- it's a horrible experiment. It puts a population of people at risk in a way that I think is unconscionable," says Mark Wheelis, a germ warfare expert and microbiologist at University of California at Davis. Though the risk is low, Wheelis says BG is not harmless. "I wouldn't inhale a BG aerosol myself," he says. In 1988, an Army biologist recommended BG spraying "be discontinued" because the claim it "is not dangerous" is "patently erroneous." As for Zinc Cadmium Sulfide -- sprayed in some tests -- cadmium compounds are now known to be "carcinogenic to humans." The dose the sailors got is classified. All of the test ships are now retired from active duty, so are the sailors. "The old school of thought was yours wasn't to question why, but to do or die," says Druckemiller. Now some of those old sailors are asking questions. George Brocklebank formerly of the USS Power asks, "Why didn't you level with us?" Robert Bates, formerly of the USS Navarro says, "They know who we all are, they know where we all live. But 35 years later the Pentagon isn't talking and still refuses to declassify much of the information about the tests.