Last year, a group of federal scientists was debating whether as many as 2,100 Air Force veterans should qualify for cash benefits for ailments they claimed stemmed from flying aircraft contaminated by Agent Orange.

An outside panel of experts had already determined that the scientific evidence showed the vets were likely exposed to the toxic herbicide.

The scientists within the U.S. Department of Veterans Affairs agreed the airmen had a strong case. But they had a more calculated concern: If the VA doled out cash to these veterans, others might want it too, according to an internal document obtained by ProPublica and The Virginian-Pilot.

The group put their worries in writing. In a draft memo, they warned the secretary of Veterans Affairs that giving benefits to the airmen might prompt “additional pressure” from other veteran groups.

Such political and financial concerns aren’t supposed to play into decisions about Agent Orange benefits, veterans advocates and some legal experts say. Federal law requires that, in most cases, these decisions be guided strictly by science.

But an examination of two recent cases illustrates how dueling considerations of liability, responsibility and evolving scientific evidence weigh into VA deliberations.

“This shows what we’ve already suspected: At the VA, they’re more interested in politics, and protecting their turf and their bonuses than fulfilling their mission to assist veterans,” said John Wells, a Louisiana lawyer who has spent more than a decade advocating for 90,000 Navy vets fighting for Agent Orange benefits.

VA officials say they are committed to making sure qualified vets get benefits, and they believe the law allows them to consider the ramifications of their decisions when weighing the eligibility of new groups.

“Considering second order effects of a decision does not in any way violate the Agent Orange Act,” the VA’s general counsel’s office wrote in response to questions.

For the past year, ProPublica and The Pilot have been examining the effects Agent Orange has had on a growing group of veterans and their families. Decades after the end of the Vietnam War, many are suffering an array of health consequences and are struggling to prove they were exposed. In interviews, they blame the VA for obstructing their claims through denials or ever-escalating requests for information, a process some call “delay, deny, wait till I die.”

Some 2.6 million Vietnam veterans are thought to have been exposed to — and possibly harmed by — Agent Orange, which the U.S. military used to defoliate dense forests, making it easier to spot enemy troops. But only vets who set foot in Vietnam or the Korean demilitarized zone — earning a status called “boots on the ground” — or served on ships that entered Vietnam’s rivers are automatically eligible for compensation for illnesses linked by the VA to the herbicide. Coverage for other groups may be added at the VA’s discretion, at a cost the VA has estimated could be billions of dollars.

As the VA studies whether to expand its list of Agent Orange-related conditions, the possibility that outside factors may be influencing its decisions worries veterans’ advocates and lawyers.

“Their charge is not to decide who they give stuff to,” said Rick Weidman, legislative director for Vietnam Veterans of America. “It’s a question of what (veterans) deserve because of scientific and medical evidence that’s related to the exposure.”

Typically the VA’s internal deliberations are conducted in secret, with only the final decisions made public. ProPublica and The Virginian-Pilot were able to learn details of two recent Agent Orange decisions by obtaining internal memos and interviewing a participant.

One decision involved the Air Force personnel and reservists who, in the years after the war, served on C–123 aircraft that had sprayed Agent Orange in Vietnam. In January 2015, an expert panel of the Institute of Medicine, now part of the National Academies of Sciences, Engineering and Medicine, found evidence suggesting these vets “would have experienced some exposure to chemicals from herbicide residue when working inside” the aircraft.

In response, the VA formed an internal working group to help senior officials brief VA Secretary Robert McDonald on options for compensating these veterans.

The working group drafted a memo acknowledging that the scientific evidence was “fairly straightforward.” In weighing how to respond, however, it listed pros and cons of various options for granting benefits to the reservists that had nothing to do with the science. One con noted that such a decision “may result in additional pressure by other veteran groups to further expand the presumption of exposure.” In parentheses, the report named specific groups of Vietnam-era veterans that might be encouraged by the change, including those who served on a base in Thailand where Agent Orange was sprayed, those who believed they were exposed on ships off the coast of Vietnam, and those who served at U.S. bases where the chemicals were tested.

On the pro side, a decision favorable to the vets “would demonstrate commitment by the VA to this group of veterans” and was “supported by science,” the memo said.

The working group recommended that the VA review claims from C–123 aircrew on a case-by-case basis rather than automatically approve them for the group. This, VA staffers calculated, could lead to “possibly reduced pressure by other veteran groups” who desired benefits while also satisfying members of Congress worried about the growing tab for Agent Orange-related benefits, according to the memo.

McDonald ultimately granted disability benefits to all Air Force and Air Force Reserve personnel who regularly served aboard the aircraft, a group estimated at between 1,500 and 2,100, saying in a statement that it was “the right thing to do.”

The VA, in an email, said the process was intended to ensure McDonald had all the information necessary to make a decision. “When making important policy decisions, the Secretary is presented with a broad array of potential courses of action, each of which have their own implications and 2nd/3rd order effects which need to be considered and discussed,” it said.

Bart Stichman, co-executive director of the National Veterans Legal Services Program, which has tangled with the VA in court on numerous Agent Orange-related issues, said it’s reasonable to expect the VA to consider a host of issues, including costs, when making decisions.

“There should be a full flow of advice,” he said. “I wouldn’t want to chill people from giving advice to the secretary and say you can’t talk to the secretary about political things.”

But Michael Wishnie, a Yale Law School professor who worked with the C–123 veterans seeking benefits, said it was against the law for the the VA staff to point out how the decision to give aircrews benefits could embolden or dampen the enthusiasm of other veterans groups.

The VA estimated the decision to compensate that relatively small group of Air Force vets would cost the government $47.5 million over 10 years.

Several years earlier, in 2009, in another internal deliberation reviewed by ProPublica and The Pilot, the VA was considering a far more expensive proposition: To grant Agent Orange benefits to veterans with Parkinson’s disease, ischemic heart disease and hypertension, more commonly known as high blood pressure.

The Institute of Medicine had found evidence suggesting a connection between Agent Orange exposure and those three conditions, and the VA’s internal working group of scientific experts wanted to recommend the department grant benefits to veterans with those conditions, according to Dr. Victoria Cassano, a member of the group who at the time was acting chief consultant for the VA’s Environmental Health Strategic Healthcare Group. But the group’s superiors at the VA told the panel to change its position and instead recommend against providing benefits for heart disease and hypertension, Cassano said. It recommended in favor of Parkinson’s disease.

In an interview, Cassano said the evidence to link those conditions with Agent Orange was at least as strong as for other diseases officially tied to the herbicide. The group was given no reason for the directive to change the recommendation, she said.

“I remember having trouble rewriting the recommendations and recommending against what I originally recommended,” Cassano said. “I understood that there were other things going on beyond the science and that my perspective at that time was that these people had more experience with the system and how this stuff falls out than I certainly did.”

In late 2009, under pressure from veterans groups, former VA Secretary Eric Shinseki said he would add ischemic heart disease and Parkinson’s disease to the VA’s list, but not hypertension, a condition that affects a third of adults in the U.S., including potentially hundreds of thousands of Vietnam veterans. According to Shinseki’s testimony to Congress in 2010, “the evidence regarding hypertension was less compelling” than for the other conditions.

But Cassano said that’s not what she, and other panel members, had found.

In an email relayed by a VA spokesman, Dr. Ralph Erickson, the VA’s chief consultant of post-deployment health services, said he and Dr. Peter Rumm, director of pre–9/11 era environmental health, were not at the VA in 2009, when Cassano was there.

“Honestly, even if we had been VA employees then, it would be inappropriate for us to discuss these internal deliberations,” Erickson wrote.

Since that time, Erickson noted, the VA has twice reconsidered whether to add hypertension to its list but declined to do so. “Each time the Secretary (who is the ultimate decision-maker) decided that the totality of the scientific evidence did not support creation of a new presumption,” he wrote.

Dr. Kenneth Ramos, who chaired a different Institute of Medicine panel that issued a report on Agent Orange earlier this year, said the evidence linking high blood pressure to Agent Orange is at least as strong as the evidence for other conditions already on the VA list. But given the prevalence of the condition in the U.S. – “a disease of aging and of lifestyle” – he said he understands the VA’s reticence.

“There’s evidence that says as (veterans exposed to Agent Orange) aged, hypertension rates have been higher,” Ramos said. “So now are you able to say the condition is service connected? It’s a really hard question to answer.”

Advocates for veterans still fighting for benefits say they are worried about the way in which the VA deliberates such issues. This is especially true among those pushing for benefits for 90,000 so-called Blue Water Navy vets, who served off the coast of Vietnam.

Although the herbicide wasn’t sprayed over the ocean, Navy veterans believe the chemicals contaminated the coastal waters sucked into their ships for drinking water. A study for the Australian Department of Veterans’ Affairs lends support to that theory. (ProPublica and The Pilot have previously written about their push for benefits.)

Rep. Chris Gibson, R-N.Y., who is co-sponsoring legislation that would force the VA to compensate the Blue Water vets, said the VA should not be basing decisions on whether they’ll spur others to demand compensation.

“The fact that they were looking at the impacts on other groups such as Blue Water Navy … this is outrageous,” Gibson said. “The focus of the veterans administration is to help our veterans, to ensure they get the health care that they have earned, the other benefits.”

Rory Riley-Topping, a former staff director for the House VA Subcommittee on Disability Assistance and Memorial Affairs, said her sense is that the VA is “very adamantly opposed” to providing benefits to the Blue Water veterans, in part because of the cost.

When she worked for the House, Riley-Topping said, VA officials were nervous that 2012 legislation that now provides health care for vets exposed to contaminated water at Camp Lejeune in North Carolina would leave an opening for the Blue Water vets. “That was one of the concerns the VA had raised at that time,” she said, echoing some of the arguments later raised about the airmen.

The VA has estimated that providing benefits to Blue Water vets would cost taxpayers $4.4 billion over 10 years, and the first year would cost the most – $1.3 billion — because of pent-up demand. A recent Congressional Budget Office estimate is substantially lower, pegging the cost at about $1.1 billion over a decade.

“On the one hand, yes, I get that’s a concern of theirs,” Riley-Topping said of the VA. “But on the other hand, those are not the types of things they should be looking at when they’re making that determination. Whether groups are empowered one way or the other has nothing to do with scientific evidence. It just doesn’t.”

Join ProPublica and The Pilot for a forum on Agent Orange in Washington, D.C., on June 30. Entitled A Toxic Legacy: Has Agent Orange Hurt the Children of Vietnam Vets?, it will explore questions about the multigenerational effects of the herbicide. Read more information about the event.