A decorated Army veteran who battled the VA over treatment for cancer he claimed to have gotten from working over burn pits in Iraq has died, his family said Monday.

Former Army Sgt. John Marshall, who went to his grave believing his cancer was caused by standing over burn pits where the military disposed of everything from disabled IEDs to lithium batteries, died at his home in Surprise, Ariz., March 29. He was 31, and left behind a wife and two young children.

"John was the type of guy who touched people even if he didn't know them that long," said Marshall's wife and fellow veteran, Ashley. "The amount of people that have come from all over to offer condolences has been amazing and overwhelming. I knew John was a great person, but it shouldn't have amazed me as it did that so many other people thought so, too."

"John was the type of guy who touched people even he didn't know them that long."

- Ashley Marshall

In February, FoxNews.com wrote about Marshall's struggle after being diagnosed with soft tissue sarcoma two years ago. He claimed the VA ruled his illness was not related to his service, and Marshall said he was unable to appeal the ruling with evidence because he was laid up in a hospital bed in January 2015 with pneumonia.

“It’s all just a big slap in the face,” Marshall told FoxNews.com. “I tried to be the perfect soldier. I did everything I was told, and now they just forced my claim through and denied coverage and my benefits.”

VA officials told FoxNews.com at the time that they would re-examine his case, but by then, Marshall's cancer had reached the terminal phase, according to his wife.

The family raised money for his private medical treatment through a GoFundMe.com page, where friends and strangers continued to offer support on Monday.

"As retired Army, we are saddened that the VA did not come through for you," wrote Bob and Edna Woods in a post that accompanied a donation. "You and your family are in our prayers. God bless!"

"The support for my husband is so heartwarming and beyond what I ever thought would happen when this journey started," Ashley Marshall wrote on the site.

Marshall told FoxNews.com he had no doubt that the soft tissue sarcoma he was diagnosed with 14 months ago is a result of his work on Improvised Explosive Device Disposal (IEDD) units.

“During my second tour, we were providing security for the EOD [Explosive Ordnance Disposal] guys,” he said. “We didn’t know what we were blowing up, so it’s possible that there we were exposed to something toxic. We stood over open burn pits.”

An October 2013 report from the United States Government Accountability Office identified open burn pits as the likely cause of long-term health issues for many veterans returning from service in the Middle East.

“The U.S. military returning from Iraq and Afghanistan may be suffering chronic, long-term health issues as a result of exposure to toxic fumes from open burn pits,” reads the report. “Defense contractors have used burn pits at the majority of U.S. military bases in the Middle East as a method of military waste disposal. All kinds of toxic waste have been incinerated in these open burn pits, including human waste, plastics, hazardous medical waste, lithium batteries, tires, hydraulic fluids and vehicles -- often using jet fuel as an accelerant.”

Perry Chiaramonte is a reporter for FoxNews.com. Follow him on Twitter at @perrych