A gas leak is suspected in a Friday morning explosion that leveled a home in St. Paul, leaving the 80-year-old property owner hospitalized and causing serious structural damage to surrounding buildings.

The first call came in just after 8:30 a.m. in the vicinity of the 600 block of Payne Avenue after the explosion took out the entire home and damaged surrounding structures, sending debris and flames into the air.

Deputy St. Paul Fire Chief Dave Berger said one male victim was conscious when he was taken to Regions Hospital.

John Lundahl was listed in critical condition at Regions Hospital in St. Paul on Friday night, a hospital spokeswoman said.

“He was speaking when he left the scene, he had some burns to his hands, with the only concerns that something like that could involve internal injuries,” Berger said. “He was pretty dazed.”

Although the blast remains under investigation, Berger said a gas leak could be the culprit.

“That’s the initial assumption,” he said. “With something of this magnitude, the first thing we think of looking at is a gas explosion. There are few other things that it could be.”

Assistant Fire Chief Matt Simpson said eight adults in all were displaced by the explosion, though it was not immediately clear if all of them lived in the house that exploded. Two dogs and a cat from neighboring homes also survived the blast.

Gas and electricity has been turned off to the entire block. City officials couldn’t immediately say how many people were without power or for how long. Just about every building nearby was damaged by the explosion, said Angie Wiese, fire safety manager for the city of St. Paul.

Two neighboring houses and three storefronts have been condemned by the city and more buildings are being evaluated, Wiese said.

It wasn’t clear exactly how many people were living in the two neighboring houses, one of which was divided into a duplex, Wiese said.

“The two houses will be condemned for quite some time,” she said. “One has some significant structural damage and the second isn’t safe enough for us to make a full assessment.”

The three storefronts received lighter damage, and it is possible they could reopen for business within a week, she said.

A number of people who live nearby saw or heard the explosion. Jerry Schaefer, who had just opened his nearby floral shop Jerry’s Roses, said he was looking out his front window when it happened. He said it sounded like a sonic boom, knocking merchandise off his shelves and rattling his windows. He said he saw flames shoot as high as 50 feet into the air.

“It was like a scene out of a movie,” Schaefer said. “It was crazy to see.”

Natasha Mancia, who lives in another house close to the blast, was awake but still in bed when she heard what she thought was a car crashing into her house. “It was nothing I ever heard before,” Mancia said. She said windows were blown out on her house.

Mancia, who also works at a convenience store in the same area, said an older man lived in the house that exploded. She said he was a regular at the store but that she didn’t know his name.

By later Friday morning, many neighborhood residents were milling near the explosion site, some taking pictures or video of the destruction. Pieces of the wooden house littered nearby yards and streets, with some debris in trees as high as 20 to 30 feet off the ground.

Xcel Energy, which provides gas and electric service to the block where the explosion occurred, said outages were limited to the immediate vicinity.

“Our thoughts are with the residents affected by this incident. We are working with fire officials and emergency responders on the scene, and our emergency responders have completed safety checks of the area to confirm it is safe,” the company said in a statement. “We will coordinate with fire officials on the investigation into the cause of the incident. Protecting the safety of the public and of our employees is a core value and we take it very seriously.”

Star Tribune staff writers Liz Sawyer and Paul Walsh contributed to this story. tim.harlow@startribune.com • 612-673-7768 greg.stanley@startribune.com • 612-673-4882