Miami, FL – A passerby with a prosthetic leg hopped over a fence and rushed into the smoldering ruins of a Westchester home Tuesday morning to save a man scorched and mangled when his house exploded.

The victim told firefighters he had been relighting a gas stove when the explosion occurred.

The man was hurled onto a backyard deck, a few feet from the pool, where he lay helpless, his clothes literally melted.

Fortunately for him, William Harris, 32, was driving past on his way to work at a security company. Harris heard a thunderous ”thud” and turned around the car to see what had happened.

The roof of the home 10130 SW 34th St. had caved in from the explosion and smoke was rising. Harris parked his car and despite his prosthetic left leg — the result of a wood chipper accident when he was 18 — jumped the fence and rushed into the back yard. There, he found the victim “burned head to toe.”

A woman was screaming, “Oh my God! Oh my God!”

Said Harris: “I should have been scared. But I had to help. I guess that’s just human nature.”

Another good Samaritan — still unidentified — was already assisting the victim, dousing him with pool water.

Harris hunted for cloth to use as tourniquets.

He couldn’t find any so he used what he had: the small patches of fabric that had not yet melted unto the man’s skin.

Then he cleared a path through the glass and debris-strewn living room so paramedics could get through to the back.

Jose Aragua, a Miami-Dade police officer, was the first official responder on the scene.

”They were doing what they could,” he said later. “But at the same time, they were all in shock.”

Aragua told the two rescuers and the woman to leave for their own safety. The fire was spreading and there were propane tanks in backyard.

About 60 Miami-Dade firefighters worked to extinguish the blaze.

Among those drawn to the scene: Josefina Calderin. She was having breakfast and reading the paper when she heard the explosion two doors to the east.

”I thought it was something like what happened yesterday in Virginia happening at FIU,” she said. The university’s main campus is about two miles away.

She ran into the backyard and saw “big, dark smoke coming from the house. And the smoke got darker.”

Calderin ran to check on an elderly neighbor whose windows had been blown out by the shock of the explosion.

She and other neighbors watched as man in the house, described as in his 20s, was carried out and airlifted to the burn unit at Jackson Memorial Hospital. His name and condition were not immediately available.

Lt. Elkin Sierra with Miami-Dade fire rescue said a second victim was found blocks away with minor burns, but he had no other information about that victim.