Hartford — Family members of two men seriously injured in an explosion are raising money to help handle the expense of their medical treatment in Boston.

Mark Kidder and Chris Macedo received second- and third-degree burns on Tuesday while using a blowtorch to remove the gas tank of a 1970s Chevrolet Camaro, and have received skin grafts at Massachusetts General Hospital, according to Kidder’s daughter, Ashlyn Moore.

The men are responding well, Moore said, but to defray mounting expenses from treatment and lodging for family members, she opened a campaign on the online fundraising website GoFundMe.

“He’s going to be down there for God knows how long,” Moore said of her father. “(My relatives) have enough to worry about with my dad; I don’t want them to worry about, ‘How are we going to stay down here, how are we going to pay for this?’ ”

Kidder, who turns 52 on Tuesday, is an employee at the West Lebanon post office, his daughter said, and once worked at Kidder Automotive. Macedo, who is in his 20s, had just started work on the day of the explosion.

So far, Moore, who works at Dartmouth-Hitchcock Medical Center, has raised $610 toward a $5,000 goal. She said a second fundraiser also was in progress, this one launched by Macedo’s girlfriend.

Emergency workers on Tuesday responded around 4:30 p.m. to reports of an explosion at a garage on Old River Road in White River Junction.

Charles Gordon, who owns the building, was there when the explosion occurred. A close friend of Kidder’s, Gordon was watching him and Macedo work on a car that a Canadian collector had sent them for refurbishment.

The tool that the men normally would use to remove the gas tank was broken, Moore said, so, assuming there would be no fuel in the decades-old, unused vehicle, they used a torch to cut the tank’s strap.

The result was a fireball.

“To be honest, it was such a shock,” Gordon said. “It was like, boom, and my friend’s on fire. I was trying to grab something, and they were running.”

Kidder jumped in a pool of water. Gordon jumped on Macedo, smothered the flames with his body — “I couldn’t find nothing else,” he said — and then started spraying the men with a hose.

Another man arrived on the scene soon after to take over the hose while Gordon went to call emergency services. After some hangups with dispatchers — Gordon said he was routed to officials in New Hampshire and Burlington who were unable to understand him in his panic — someone else drove to the nearby fire department for help.

Paramedics took Gordon, Kidder and Macedo to Dartmouth-Hitchcock. From there, Kidder and Macedo went on to Boston, and Gordon, who had minor injuries, was sent home.

Gordon had been shielded from the blast by Macedo, Moore said, and suffered smoke inhalation and abrasions. Kidder, by contrast, received burns on his arms, hands and across the front of his body.

On Friday, Gordon said his health was as “good as could be expected.”

“All the excitement of everything that was going on took its toll,” he said, “but nothing compared to what happened to my guys.”

In the wake of this incident, Scott Cooney, Hartford’s interim fire chief, advised residents to take every possible precaution while working on cars to avoid igniting flammable materials.

“I think our take-home message from events such as this would be to exercise extreme caution when using flammable torches or cutting equipment, whether it be grinding or cutting, anywhere near gasoline,” he said.

To ensure a gas tank is empty, Cooney said, he might go so far as to disassemble it with manual tools instead of using a cutter — or even fill the tank with water first.

Moore and her mother have been making visits to Kidder in Boston, and they say his treatment is progressing well, although doctors can’t yet predict how long it will take.

“He’s doing OK,” she said. “They have his bandages off of his arms so the skin grafts can get some air and acclimate.”

As the men recover, Gordon and Moore asked friends and residents to send their support.

“We need lots of good thoughts,” Moore said.

The GoFundMe page for Mark Kidder can be accessed at https://www.gofundme.com/2d2sz2s.

Rob Wolfe can be reached at rwolfe@vnews.com or at 603-727-3242.