From the 1950s through the mid-1970s, more than 7,000 volunteers, all soldiers in the U.S. Army and Air Force, were subjected to a variety of chemical gases and other substances in a secret, Cold war program.

One of those volunteers was Eric Muth of Milford, who over the years amassed a trove of documents and images about the program, which supported U.S. chemical and biological warfare efforts. Now he’s donated his collection to the Army’s Chemical Corps Museum.

Its director has thanked him profusely, saying the donation contains material that the Army no longer had.

Muth, 78, said he curiously signed up for two 30-day tours with the chemical warfare unit. The first was in May-June 1958 and the second was six months later.

“I guess I wanted to prove that I was a hero,” he said recently, with a laugh. “Over half of us aren’t with us anymore.”

Some of the photos and documents Muth saved while he was with the chemical exposure program; some he acquired during a 2009-17 lawsuit brought by the human subjects.

Although the Army at one time had access to most of the donated material, Muth says much of it was purged over the years — for a time, the Army didn’t want anyone to know about the program and had destroyed files and other materials connected with it, he said.

Muth also had in his files photographs of the volunteers who were at the secret Edgewood Arsenal in Maryland while he was there.

The chemical exposure research took place at Edgewood, according to evidence that became known during the civil suit. It’s believed that about 7,000 volunteers signed up for the experiments, and about half were exposed to a wide assortment of toxic agents.

“When I was 17, I saw this ad on a bulletin board that said ‘Volunteer for the Chemical Corps to Test Riot Gas,’ ” Muth said. “But of course, there were toxic gases that we had to be subjected to, too.”

He said that some contained arsenic, “and made me puke,” he said. Others were nerve and mustard gases developed by the Germans during World Wars I and II. It was revealed during the court case that former Nazi scientists were consulted about some of the toxins that the volunteers were being subjected to.

These Nazi scientists, some of them with notorious reputations, were brought over to the U.S. to assist in the Cold War effort in what was called Operation Paperclip. At least eight were involved in the Edgewood experiments — which Muth said looked like something out of the H.G. Wells classic, “The Island of Dr. Moreau.”

“I remember going into a room and there were all sorts of animal experiments going on,” he said. “Cats with exposed brains. Animals with limbs grafted on from other animals.”

Volunteers, he said, drank liquids containing the hallucinogen LSD (or lysergic acid diethylamide) as part of experiments that had to do with interrogation techniques. The Army was also interested in incapacitating large numbers of people at once as a way of waging a “more humane” form of warfare.

“And I was subjected to psycho-chemicals,” he said. “A very concentrated dose of THC, the drug in marijuana. The callousness they displayed to our own people — it’s so over-the-top, it’s almost humorous.”

To be exposed to toxic gases, soldiers were herded into a room called “The Wind Tunnel.”

“It had a big fan at one end,” Muth said. “That was to evacuate the gases from the room, so they could get the room ready for the next group. So, if you were buying a home back in the 1950s and ’60s, you wouldn’t want one near Edgewood.”

Not that you would ever know. Edgewood was a top-secret operation back then, and almost no one outside of the Defense Department knew about what was going on there.

“In the Cold War, you could get away with just about anything as long as you were ‘fighting Communism,’ ” Muth said.

The program was abruptly halted in 1975 after Congress began looking into the operation and the ethical lapses going on.

For example, members of Congress were shocked to discover that there was no follow-up care offered to the volunteers, and that the subjects were never told what substances they were exposed to.

In 2009 the surviving volunteers sued the government and eventually won their case. The Army agreed to provide for their health costs over and above whatever care they were getting from VA hospitals. It also agreed to let the surviving volunteers know more about the substances that they were subjected to.

After completing his stints with the chemical warfare unit, Muth returned to Fort Leonard Wood (in Missouri) to serve the remainder of his Army tour. Later, he signed on with the National Guard, where he served at the Nike surface-to-air missile radar site in Milford.

“Near the end of the program, volunteers had to agree to a 60-day period,” Muth said. “I guess they were having trouble hanging onto people.”

In spite of all of the horrific activities that occurred in Edgewood, the director of the Army Chemical Corps Museum, Kip A. Lindberg, was happy to get the materials from Muth.

“Our archival files are sadly lacking in documentation of this program, and your donation has done much to fill that void,” Lindberg said to Muth in his letter.

The Chemical Corps Museum is at Fort Leonard Wood.

Indeed — one of the documents that Muth had was a memo about a commander getting rid of an entire filing cabinet full of important records.

Today, Muth suffers from a several ailments, some of which he attributes to the chemical exposure experiments. Still, he harbors no resentment toward the Army, and he likes to wear his Army T-shirt when he putters around the house. A dress uniform hangs the doorknob to his home office.

“The Army didn’t do this to me — it was the CIA, the pencil-pushers,” he said.