OLD TOWN, Maine — A fire in a lime kiln at Old Town Fuel and Fiber sent six firefighters to the hospital for precautionary reasons.

At about 6:40 a.m., a small fire got away from workers at the mill and the fire spread to the exterior walls of the building, said Old Town Fire Chief Steve O’Malley.

“The reason we were there so long is the fire got into the walls,” he said. “When it gets inside the walls, it just stays there inside the insulation. We had to tear down the walls to put the fire out.”

Crews from Old Town, Orono, Milford and Bangor arrived and cleared the scene at approximately 10:30 a.m. O’Malley said 25 firefighters were there.

Firefighters attacked the fire from both inside and out. Because of the high pH level of the lime and its reactiveness to water, some firefighters received rashes on exposed skin, O’Malley said. The six firefighters were transported to St. Joseph Hospital in Bangor as a precaution.

O’Malley said the firefighters were fine and didn’t lose any work time.

Even with the firefighters battling the blaze, production at the mill never stopped, he said.

The cause of the fire hasn’t been determined, but O’Malley said he believes some of the lime dust caught on fire.

“Anytime you have hot machinery around dust, you have the chance of heating it up to its combustion point. That would be my guess from prior fires down there,” he said. “We’ve not had a chance to fully investigate the fire [however].”

Lime is used in the paper pulp process, he said.

O’Malley said there was not a lot of damage done to the mill.

“It was in the walls. It didn’t affect the machinery,” he said. “The fire was in a second floor wall and a little bit of the roof.”