Yellowknife (Nov 03/06) - Authorities have launched an investigation into a blaze that gutted an air tanker base near the Yellowknife airport Wednesday evening.

The damage to the building, owned by the territorial Department of Environment and Natural Resources (ENR), could be upwards of $300,000, according to police.

Smoke billowed from a blazing fire at an air tanker base near the Yellowknife airport Wednesday evening. It took fire crews three-and-a-half hours to get the fire under control. - Jennifer Geens/NNSL photo

The investigation is being conducted by the RCMP and NWT fire marshal Bernie Van Tighem. Government officials and the fire department are not sure what sparked the flames.

Firefighters fought the blaze over the course of three-and-a-half hours. Their efforts were hampered by explosions caused by flammable materials like gasoline, said deputy fire Chief Darcy Hernblad.

Twenty firefighters from the Yellowknife Fire Department responded to a call for additional assistance from airport fire crews at 5:43 p.m.

Plumes of grey and black smoke poured from the roof of the building. They were interspersed with bursts of flames from several explosions inside the structure.

Police and airport officials cordoned off the area and blocked-off Bristol Road, evacuating all non-essential personnel from the area.

Two airplanes near the fire had to be moved to a safe distance. Kevin Morneault, an Air Tindi employee, heard the fire call on his radio after one of Tindi's flights. He, along with a second Air Tindi worker, helped fire crews move the planes.

"There was a lot of smoke," said Morneault. "The back of the (building) had a huge burn mark on it."

Lance Schmidt, North Slave manager of forest fires for ENR, said no one was in the building at the time of the blaze.

"It was a seasonable base used from May to August," said Schmidt.

Schmidt described the building as a two-car garage.

The metal building held air compressors, water bomber airplane oils, and a vehicle, he said.

"In the short term, we have to try to figure out how to replace those items," said Schmidt. A preliminary report pegged the damage at $300,000, according to a RCMP media release.

ENR owns three other buildings at the air tanker base.

The blaze did not disrupt departures from the airport, but planes near the fire had to ask for authorization before takeoff, said Department of Transportation spokesperson Bob Kelly.

Some planes from smaller air companies scheduled to land around the time of the fire were delayed coming into the airport, he said.