C-123s are big cargo planes. During the Vietnam conflict they were used to spray Agent Orange, a toxic defoliant.

But the planes have a lesser-known history: They were used here in the U.S. by the Air Force reserves from 1972 until the early 80s. Crews in Ohio, Pennsylvania and Massachusetts spent hours on the planes, many on medical flights. Major Wes Carter was a medical technician in the reserves in Massachusetts at the time.

"We knew of their history. However, it was a period of innocence. Everybody thought that with the spray tanks removed that there was no lingering problem," Carter said.

'Patches' and other legacies
Decades later, Carter and other former C-123 crewmen started getting sick.

"In 2011, I had a heart attack and was informed the same week that I had prostate cancer," Carter adds.

Carter did some research, and discovered the planes were still contaminated with Agent Orange, which contains highly toxic dioxin. He found out one of the C-123s, nicknamed “Patches," was actually removed from display at the Air Force Museum in Dayton in the mid-90s for decontamination. Documents show the Air Force was worried about workers and even tourists being exposed.

“Patches” was put back on display at the museum and can still be seen today. The museum says it has never had any complaints from workers about possible exposure to Agent Orange.

VA has not embraced the claims
But until this month, the VA has denied almost all claims for C-123 vets.

Dr. Jeanne Stellman, an Agent Orange expert at Columbia University in New York, worked on an article published last year that blasts the VA for ignoring the science.

"It seemed to us to be a total no-brainer that there was exposure possible," Stellman said. 

Now a study commissioned by the VA from the Institute of Medicine  says reservists quite likely did experience exposure that could be damaging. Dr. Ralph Erickson is a VA health expert based in D.C.

"I think we’re a learning organization, we’re able to make the adjustments that are necessary, and we’re basically moving forward at this point," Erickson said.

He says a task force will make recommendations to the VA secretary on next steps within months. Two weeks ago the VA updated its website to acknowledge the findings and encourage vets to file claims.

The number of Air Force reservists who could have been exposed to Agent Orange is unknown, but could be up to 2,100.