Retired Air Force Maj. Wesley Carterat his home in McMinnville, Ore. (Leah Nash/FOR THE WASHINGTON POST)

Nearly three dozen rugged C-123 transport planes formed the backbone of the U.S. military’s campaign to spray Agent Orange over jungles hiding enemy soldiers during the Vietnam War. And many of the troops who served in the conflict have been compensated for diseases associated with their exposure to the toxic defoliant.

But after the war, some of the planes were used on cargo missions in the United States. Now a bitter fight has sprung up over whether those in the military who worked, ate and slept in the planes after the war should also be compensated. Two U.S. senators are now questioning the Department of Veterans Affairs’ assertions that any postwar contamination on the planes was not high enough to be linked to disease.

Complicating the debate is that few of the planes remain to be tested. In 2010, the Air Force destroyed 18 of the Vietnam-era aircraft in part because of concerns about potential liability for Agent Orange, according to Air Force memos documenting the destruction.

Citing tests done on some of the aircraft in the 1990s, North Carolina Sen. Richard Burr, the ranking Republican on the Senate Veterans’ Affairs Committee, and Sen. Jeff Merkley (D-Ore.), have asked the VA’s Office of Inspector General to review whether the department is “inappropriately” denying disability compensation to veterans who claim they were sickened by postwar contamination.

“It appears that [the VA] does, in fact, plan to deny any C-123 claims regardless of the evidence submitted in a particular case,” the senators wrote. The letter notes that a group of outside experts have called the VA’s scientific conclusions “seriously flawed.”

The Air Force says the planes’ destruction was handled properly.

“Because of the potential stigma associated with these aircraft, the Air Force ensured that the recycling of the aircraft was accomplished completely and that the metal was not stored improperly or abandoned prior to being smelted,” an Air Force statement said.

The C-123s were used to spray Agent Orange from 1962 to 1971 as part of Operation Ranch Hand. After the war, about 1,500 Air National Guard and Reserve crew members flew the planes on cargo missions in the United States until the last aircraft were retired in 1982.

The Air Force aborted plans to sell some of the planes in 1996, after evidence surfaced that 18 of them might still be contaminated with TCDD dioxin, a carcinogen associated with Agent Orange, according to Air Force documents and papers filed with the General Services Administration’s Board of Contract Appeals. The planes were quarantined instead in Arizona at a storage facility at Davis-Monthan Air Force Base, nicknamed “the Boneyard.”

The Air Force did not notify the post-Vietnam crews or Boneyard employees of the potential risk, according to Air Force documents.

When tests on four of the quarantined planes in 2009 showed little or no remaining dioxin, the Air Force decided it was safe to destroy the aircraft.

Officials at Hill Air Force Base in Utah, which oversaw the planes, approved a consultant’s recommendation in 2009 to “dispose of/recycle the 18 UC-123K ‘Agent Orange’ aircraft as soon as possible to avoid further risk from media publicity, litigation, and liability for presumptive compensation,” according to a base memo in August 2009.

“The longer this issue remains unresolved, the greater the likelihood of outside press reporting on yet another ‘Agent Orange Controversy,’ ” consultant Alvin Young wrote in a report.

Base officials recommended that the aircraft be “shredded into cell phone-size pieces” and melted. “Smelting is necessary for these 18 aircraft so the Air Force will no longer be liable for ‘presumptive compensation’ claims to anyone who ever works around this ‘Agent Orange’ metal,” an Air Force memo said in September 2009.

In 2010, the aircraft were torn apart by heavy machinery, melted and poured into blocks.

“The toxic aircraft had to be eliminated,” said Wes Carter, a retired Air Force major who served aboard C-123s as a medical service officer in the United States for a decade. “The right thing to do would have included telling the veterans of the exposures so that health and well-being as well as rights to seek veterans benefits would all be protected.”

An Air Force review last year concluded that “given the absence of a clear finding of potential harm,” it was not necessary to notify the crews.

Carter, 66, had potentially lethal prostate cancer diagnosed in 2011. His doctor, Mark Garzotto, director of urologic oncology at the Portland Veterans Affairs Medical Center, wrote in February that the cancer is “likely related to your exposure [to] Agent Orange.”

But the VA has rejected compensation claims filed by Carter and other veterans who served on the aircraft after the war, saying their exposure to Agent Orange was too limited to connect to the diseases.

The VA is committed to reviewing claims on “a case-by-case basis,” the department said in a statement. “VA does not have a ‘blanket policy’ for denying claims” filed by postwar C-123 veterans, VA Secretary Eric K. Shinseki wrote Burr, the senator, in June.

‘VA is very concerned’

Under federal law since 1991, the VA has granted the presumption of exposure to Agent Orange to any member of the military who served in Vietnam during the war. Some 260,000 cases have been filed since 2010, helping to fuel the backlog of disability claims facing the VA.

By 2009, the VA had agreed to compensate veterans who could show they were exposed to the defoliant during wartime testing in the United States.

The C-123 aircraft cases might open up claims for postwar service, as well, according to Young, the Agent Orange consultant who advised the Air Force.

“What this means is that a whole new class of veterans may claim that their exposure was due to the fact they were members of aircrews or mechanics associated with the contaminated aircraft that returned from Vietnam,” Young wrote in a June 2009 memo to Hill AFB.

A retired Air Force colonel and former professor of environmental toxicology at Oklahoma State, Young frequently serves as a consultant on Agent Orange for the Defense Department. The 2009 memos list him as a consultant on Agent Orange to the Office of Secretary of Defense; Young said he was advising Hill AFB in an “unofficial capacity.” Both Young and the Pentagon say the consultant was not under contract with the Defense Department at the time.

Young said in an interview that the decision to destroy the planes “had nothing to do with claims. There was never any destruction of evidence.”

Carter, an Oregon resident, and his comrades in the C-123 Veterans Association say postwar crews should be eligible for the same compensation for Agent Orange provided to those who served in Vietnam. He has filed complaints with the Air Force and VA, and collected many documents via Freedom of Information requests, which he provided to The Washington Post and posted online.

A 2011 Air Force epidemiological study of the crews that sprayed Agent Orange — “the most heavily exposed veterans of the Vietnam War,” according to the report — found no link between Agent Orange exposure and their diseases.

Last year, the VA hired Young to investigate the postwar C-123 claims, and his report in November concluded that “ample evidence” disproves the veterans’ claims.

“The VA is very concerned, because it amounts to a lot of money to be paid for the rest of their lives when there isn’t the science to back it up,” Young said.

But a number of outside medical experts have concluded the veterans were likely exposed to dangerous levels of dioxins. In November, 14 prominent toxicologists sent the VA a letter saying the department’s scientific conclusions are based on “erroneous assumptions.”

“It’s not right,” said retired Air Force Lt. Col. Paul Bailey, a New Hampshire resident who served with Carter aboard C-123s and is gravely ill with cancer. “We were exposed, we can prove we were exposed, but they’re saying it doesn’t matter.”

Although the VA says there is no policy against postwar C-123 claims, Bailey was told that “VA regulations do not allow us to concede exposure to herbicides for Veterans who claim they were exposed to herbicides after the Vietnam war while flying in aircraft used to spray these chemicals,” the VA regional office in New Hampshire wrote in February, denying his claim.

The Board of Veterans’ Appeals, an administrative tribunal, has overturned VA denials several times, ruling in one case that the veteran who scrubbed planes saturated with Agent Orange after the war was exposed to the herbicide and entitled to compensation for his diabetes. But such appeals typically take years, time Bailey said he no longer has.

Disposing of aircraft

Bailey and Carter flew on one of the most famous of the C-123s for more than a decade, often eating and sleeping on the plane. Known as “Patches” for the holes left by enemy fire, it was sent to a museum in 1980.

Based on testing by Air Force toxicologists in 1994 that found Patches “heavily contaminated,” the plane’s postwar crews were exposed to dioxin “at a level greatly exceeding” the Defense Department screening levels, according to Thomas Sinks, deputy director of the federal Agency for Toxic Substances and Disease Registry.

Many of the retired C-123s ended up in the Boneyard, and in 1996 the government arranged to sell them.

But when employees at Davis-Monthan prepared the planes for buyers, they smelled chemical vapors and experienced burning sensations on their hands and arms, according to papers in a case later heard by the General Services Administration’s Board of Contract Appeals.

Subsequent testing of 17 aircraft in August 1996 detected “strong potential of low level concentrations of dioxin,” according to Air Force documents.

In December 1996, the Air Force requested the government terminate the sales, warning that “the potential for harm to individuals from dioxin contamination is great.”

Employees at Davis-Monthan were not informed of the potential contamination until two years later, according to Air Force documents.

In 1998, the aircraft were fenced off in a restricted area and were largely untouched for another decade, before Air Force officials tried again to resolve the dilemma.

They had concerns that the Environmental Protection Agency or Arizona Department of Environmental Quality could request access and levy fines, which a base official calculated could reach $3.2 billion.

“We are still at significant risk publicity wise and with AZ environmental law for these aircraft,” an Air Force officer at Hill wrote in May 2009.

The tests by an Air Force environmental office on four planes that month indicated they could be destroyed without risk to workers. Years in the Arizona sun had “likely volatilized any remaining Agent Orange,” reported Young.

“I join with Dr. Young in saying let’s get on with it,” Wayne Downs, hazardous-waste-program manager at Hill AFB, wrote Oct. 29, 2009. “Ben and Jerry’s ice cream has more dioxin than these aircraft.”

Some Air Force officials were uneasy about the failure to test all the planes. “This lack of information is causing us, and has the potential to cause us, a lot more trouble than it would have been to just sample the aircraft,” Karl Nieman, an Air Force contractor at Hill, wrote in December 2009.

Normally, aircraft at Davis-Monthan slated for disposal are turned over to a defense agency, which would have the planes cut apart by a local metal recycler. But the agency balked, maintaining that the planes should be handled by a licensed hazardous-waste-disposal firm, a process that would require “worldwide” public notification, according to an Air Force memo.

Air Force officials instead contracted with a Navy aircraft disposal office in California, which used the same local metal recycler without the notification.

“If the Air Force wants quick and quiet disposal, the Navy option is preferable,” stated an Air Force memo in September 2009.

The destruction was approved by Hill AFB in 2010. No notification of the EPA or Arizona environmental officials was required, according to the Air Force, which noted in its statement that the collaboration with the Navy included obtaining the required demilitarization and destruction certification.

On June 8, 2010, as two Air Force officials watched, the last truckload carrying 35,000 pounds of shredded aluminum metal from the Boneyard arrived at a furnace in Belleville, Mich.

The furnace was heated to nearly 1,400 degrees, hot enough to destroy any traces of dioxins. Workers dumped in the metal. By 11 a.m. the last of the C-123 remains were being poured into 2,000-pound blocks.

The blocks, the Air Force officials were told, would be sold to the automotive industry.