Dax Cowart and his father, Ray, were ready to drive home on July 25, 1973, after inspecting some land that Ray had hoped to buy in East Texas, but their car would not start.

Dax tried the ignition again, and again, hoping to coax the engine to life. His father got out and opened the hood. All the while, they were unaware that a propane pipeline ran beneath the dry riverbed where they had parked, and that it was leaking.

When the engine finally sparked, the propane exploded, engulfing both men and the surrounding area in flames. Ray Cowart collapsed, and Dax pulled himself out of the car and ran for help, sprinting almost a half-mile through walls of fire before encountering a farmer and the farmer’s nephew, who ran to call ambulances.

Dax, in agony from the burns covering most of his body, had a request for the farmer.

“I asked him to bring me a gun, and he wanted to know why,” Mr. Cowart later told an interviewer. “I told him, ‘Can’t you see I’m a dead man? I’m going to die anyway, I’ve got to put myself out of this misery.’ He said, in a very caring way, ‘I can’t do that.’ ”