FARMINGTON, Maine — A powerful propane explosion leveled a recently opened nonprofit center after crews arrived to investigate the smell of gas Monday morning, killing one firefighter and injuring six other people, including fellow firefighters, officials said.

The building had been evacuated after the gas was detected, said Farmington Town Selectman Scott Landry. One firefighter was killed.

The blast injured four other firefighters, including the town’s fire chief; one employee of the nonprofit center; and one ambulance worker, officials said. Landry had previously said all six of the injured were firefighters.

The blast around 8:30 a.m. was heard for miles and had enough force to blow a vehicle across an intersection. Paper, insulation and building debris rained on the area.

All that was left of the two-story building housing LEAP Inc., which serves people with cognitive and intellectual disabilities, was a hole, Landry said.

“It’s a war zone. It’s just a mess,” said Landry, who is also a state representative. “The building is gone.”

Kim Hilton, who works in the admissions department at the nearby University of Maine at Farmington, said there were scary moments when the blast occurred.

The ambulance worker was treated and released, state public safety spokesman Steve McCausland said.

The other five were taken to regional trauma centers, including the state’s largest hospital, Maine Medical Center in Portland, and remained hospitalized Monday afternoon, officials said. Their conditions weren’t released.

Gov. Janet Mills, who is from Farmington and whose office said she knew the firefighter who died, said on Twitter that the state fire marshal’s office will investigate.

“We’re going to get to the bottom of as much as we possibly can to protect this community, to protect all other communities and make sure this doesn’t happen again,” she said.

The 40-by-60-foot (12-by-18-meter), two-story building, which served as the administrative offices for LEAP, opened eight to 10 weeks ago and wasn’t yet fully staffed, Landry said.

The smell of gas was detected and the building evacuated before most workers had arrived for the day, he said.

Farmington is about 70 miles north of Portland.

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