A natural gas plant at Point MacKenzie restarted at 11 p.m. Thursday after shutting down earlier in the day amid a series of explosions that destroyed the facility's maintenance building.

Dan Britton, president of Fairbanks Natural Gas, said the gas flow to the plant and its power supply were shut down Thursday morning as firefighters responded to the blaze. No one was hurt in the accident.

The plant restarted at 50 percent capacity late Thursday and he expected it would reach full capacity sometime Friday, Britton said.

The 3,000-square-foot maintenance building was located away from the production plant, where the company super-chills natural gas into a liquid that then is trucked to customers in Fairbanks.

Britton flew to the Mat-Su plant from his Fairbanks office Thursday afternoon.

In all, three explosions occurred over about two hours in the maintenance building, which stored more than 30 55-gallon drums of oil, said James Steele, Central Mat-Su fire chief. The company said the drums most likely contained waste oil being stored for transport to a recycling facility.

The state fire marshal is investigating. The cause of the explosions was not immediately known. Britton said the company believes the waste oil drums generated the explosions.

The first one was reported at 7:16 a.m. by a maintenance worker at the plant, Mat-Su emergency officials said.

The worker said that after a power failure, he went into an adjacent building to recalibrate instruments when he heard a buzzing noise. "And then he heard a boom," Steele said.

Before calling 911, the worker alerted a dozing tanker-truck driver, the only other person present, to move his truck, Steele said.

Central Mat-Su Deputy Fire Chief Mike Keenan reported a second explosion as he was en route to the scene before 8 a.m., the borough said. Steele estimated flames shot 150 feet into the air from that explosion. When firefighters arrived, the building had burned to the ground, and fire surrounded a tanker, which was venting gas that was then catching on fire, they said. Crews fought the fire initially with water and foam. They got the flames somewhat knocked down, but then the fire intensified behind the burning tanker and they pulled back about a quarter-mile. The chief said the fire was burning away from the rest of the plant, so it didn't threaten the gas production area.

"At that point, it was a safety issue," Steele said. "We just pulled everyone out."

The tanker had been emptied before entering the maintenance shop, but it's possible residual gas remained, Britton said.

At the peak of the fire, two engines, three tankers, a hazardous materials team and a rescue team were on scene.

The plant is at least a quarter-mile from any homes, borough officials said. One neighbor reportedly evacuated as a precaution, the borough said.

Fairbanks Natural Gas employs eight people at the plant, one on the night shift, Britton said. It serves about 1,100 customers in Fairbanks North Star Borough, he said. Between 30 and 40 deliveries of liquefied natural gas are made each week, he said.

The company doesn't expect its natural gas supply to be disrupted; it keeps a minimum of five days' supply of liquefied natural gas stored in Fairbanks, Britton said, and shipments from Mat-Su should resume today.

The natural gas facility is about a mile away from the Point MacKenzie Correctional Farm, but Dennis Brodigan, borough emergency services director, said inmates there were not in danger.