Tens of thousands of veterans and service members stationed at military bases in Iraq and Afghanistan say exposure to trash fires or “burn pits” has left them with breathing problems and other chronic illnesses, including cancer. They are fighting for health benefits, but say the U.S. Department of Veterans Affairs is turning its back on them.

Veterans say everything went into the burn pits — plastic water bottles, spent munitions, tires, human and medical waste. They say the heaping piles of trash were often then doused with jet fuel and lit on fire. The pits burned 24 hours a day in or next to their military bases.

June Heston, of Richmond, Vermont, lost her husband Mike Heston last year.

"How can that even happen? I was mad. So mad," she said.

A Vermont widow blames the death of her husband on exposure to toxic smoke from military burn pits overseas.

Brig. Gen. Mike Heston was in the Vermont National Guard and volunteered for three tours of duty in Afghanistan during Operation Enduring Freedom.

"He was a soldier’s soldier," June Heston said. "It meant everything."

But in 2016, nearly four years after his last tour, Mike Heston started having back pain. He went to a slew of doctors who performed countless tests. He lost 75 pounds. For almost a year, no one could figure out what was going on.

"I said, 'I feel like he's dying and I'm the only one who sees it,'" Heston recalled, choking back tears.

Mike Heston was dying. He had stage 4 pancreatic cancer. But it would take new doctors in Boston and an article the veteran stumbled upon to connect the possible dots. It was about a young mother in the Minnesota National Guard, Amie Muller, whose family blamed her pancreatic cancer, and eventual death, on the burn pits at her military base in Iraq. The same kind of burn pits in Mike Heston complained to his wife about at his base.

"The military failed him. The doctors failed him," June Heston said. "I was angry."

The military started using burn pits in Iraq and Afghanistan in the early 2000s. Veterans tell NBC10 Boston Investigators they were the fastest and cheapest way to get rid of trash. Veterans say the garbage was often doused with jet fuel and set on fire. They burned day and night.

June Heston, of Richmond, Vermont, lost her husband Brig. Gen. Mike Heston last year to stage four pancreatic cancer. The Hestons believe Mike's exposure to burn pits during his time in Afghanistan is to blame.

Dr. Tom Abrams, an oncologist at Dana-Farber Cancer Institute in Boston, said he’d never heard of burn pits before meeting the Hestons.

"It was shocking to learn about them," Abrams said. "I asked, 'why is this happening? How could this be happening? This is clearly a threat to health.'"

It was Abrams' team that found Heston's cancer and while he can't prove it definitively, he told the VA the exposure "....more likely than not..." made Heston sick.

"Mike and the other patients are the canaries in the coal mine," he said. "And I think we're going to see more and more of these patients with cancers of all stripes."

Abrams' letter helped Heston gain disability medical benefits through the VA. Veterans are only eligible for health insurance for five years after service unless their illness is determined to be service related.

The VA has approved just 20 percent of the nearly 12,000 medical claims related to burn pits over the last decade. The agency admits there are toxins in the smoke, but insists most health effects are temporary.

Dr. Tom Abrams, an oncologist at Dana-Farber Cancer Institute in Boston, says he had never heard of burn pits until he treated Brigadier General Mike Heston.

"In some people it may be making them sick," said Dr. Drew Helmer, who directs the VA's War Related Illness and Injury Study Center in New Jersey. "Who it is making sick, how many people it is making sick and what is the sickness—those are still questions we don’t have answers for."

The VA says it is continuing to study the issue and in 2014, Congress mandated they create a burn pit registry to collect data on exposed veterans to better evaluate the issue and potential risk. Nearly 170,000 veterans and servicemen have signed up. Forty-two hundred of them are from New England.

June Heston said her husband did sign up for the registry once he had learned of it.

"He said, 'You don't start a registry unless you know there's a problem,'" she recalled.

Veterans and families call the registry a start, but want more education for doctors, especially civilian practitioners, and guaranteed medical care for veterans exposed. Those health benefits could cost the VA billions.

Images: From Service to Sick

Heston lost her warrior in late 2018. The husband and father of two was 58 years old.

Heston says her husband told her to keep fighting for other veterans.

Families often compare burn pit exposure to Agent Orange, the defoliant used in Vietnam, which was eventually linked to cause cancer and other diseases in exposed veterans. By the time the VA recognized the illnesses as service related, many veterans had already died without VA health benefits.

"Most of these men and women will die before any responsibility is taken and the help that they need is given," June Heston said. "That's the reality."

The Department of Defense turned down the NBC10 Boston Investigators request for an interview. They said they are now largely using incinerators, a more expensive method of getting rid of trash, but the military admits burn pits are still being used near about a dozen bases in the Middle East.

Legislators have introduced a bill called the Burn Pits Accountability Act that would require the military to track service members and veterans exposed to burn pits, require health evaluations and share data about burn pits with the public. It was referred to the House Subcommittee on Health.

If you or a loved one were exposed to burn pits in Iraq, Afghanistan, or Djibouti and you'd like to share your story with Ally Donnelly, she may be reached at Ally.Donnelly@nbcuni.com.