Matanuska-Susitna Borough officials said no one was injured the Fairbanks Natural Gas-operated facility at Point MacKenzie. The cause of the explosions was not immediately known.
Only one person was at the plant when the explosions occurred, said Dennis Brodigan, the borough's emergency services director. The worker was in another plant building and called 911, he said.
When emergency personnel arrived, they found a 60- by 30-foot building "on fire and totally down on the ground," Brodigan said.
More than 20 emergency responders and two fire engines, three water tankers, a rescue truck and a hazardous materials team responded.
Fairbanks Natural Gas employees shut off the gas to the plant.
Officials decided to let the fire burn itself out.
"We will just let it burn through the day," Brodigan said.
When crews arrived, they doused nearby tanker cars with water to cool them and kept close watch on several nearby buildings. Firefighters sprayed water on a production building.
Initially it was believed there was only one explosion. However, borough officials later said there were three, the first at 7:16 a.m. and the second shortly before 8 a.m. The third, described as small, occurred after 9 a.m. when a tanker truck inside the burning building exploded, Brodigan said.
By 10 a.m., most of the firefighters were returning to their stations to prevent their fire trucks from freezing up in the 7-degree cold, said borough spokeswoman Patty Sullivan. A crew remained Thursday morning about a quarter-mile away to monitor the fire.
"It will smolder for quite some time," Brodigan said.
Fairbanks Natural Gas LLC provides natural gas to more than 1,000 customers in Fairbanks, Alaska's second-largest city. The gas is purchased in the Cook Inlet area and condensed into a liquid. It is then trucked to Fairbanks where it is converted back to natural gas for delivery to customers.
Last year, a section of the Parks Highway - the main route between Alaska's two largest cities - was closed after a tanker rolled over carrying 9,000 gallons of highly explosive liquid methane. The methane was owned by the Fairbanks utility.