An Air Force C-123 flies along a South Vietnamese road spraying defoliants on dense jungle to eliminate potential ambush sites

DEPARTMENT OF DEFENSE 1966

WASHINGTON - 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 has called the VA's scientific conclusions "seriously flawed." But the VA is committed to reviewing claims on "a case-by-case basis," the department said in a statement.

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. After the war, about 1,500 Air National Guard and Reserve crew members flew the planes 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 at a storage facility at Davis-Monthan Air Force Base in Tucson, nicknamed "the Boneyard."

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

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.

Base officials recommended that the aircraft be "shredded into cellphone-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.