Volunteer firefighters from the town of Superior spent three hours putting out a fire at a workshop along Old Highway 105 Saturday afternoon. No injuries were reported.

A caller who reported the 1:15 p.m. fire said they heard explosions at the workshop, according to town of Superior Fire Chief Brian Laverdiere. By the time firefighters arrived on the scene, he said, the structure was engulfed and sending up black smoke. No injuries were reported.

The cause of the fire remains undetermined. There was no electricity to the workshop, but an acetylene torch was being used earlier in the day to cut springs on a semi tractor, Laverdiere said. He said the explosions were caused when the fire reached the acetylene tank as well as the oil tanks, fuel tanks and tires on two semi tractors - one inside the building and one outside the building. Estimated damages were at least $100,000, the fire chief said. Both semi tractors were destroyed.

The blaze also started some logs on fire beside the building and touched off a wildland fire.

Mutual aid was provided by the Superior Fire Department, Department of Natural Resources and volunteer firefighters from Summit, Oakland and Parkland. The recent wet weather, Laverdiere said, helped keep the wildland fire in check.