MADAWASKA, Maine — A fire that started at one of the papermaking machines at Twin Rivers Paper Co. on Sunday afternoon spread into the ductwork, making it difficult to extinguish, according to the local fire chief.

High temperatures inside the mill also challenged firefighters, one of whom had to be hospitalized for heat exhaustion.

“We knocked [the fire] down” at machine No. 7, Madawaska Fire Chief Jim Soucy said Monday morning, “but it got in the ductwork above the machine. That made it tough to get at.”

One Madawaska firefighter was taken to Northern Maine Medical Center in Fort Kent for treatment of heat exhaustion, according to Soucy. The chief said that although there were no particular difficulties working the fire around the papermaking equipment, the high temperatures inside the mill made it difficult for firefighters dressed in full gear.

Firefighter Roland Michaud was treated in the emergency department Sunday and admitted to the intensive care unit where he remained in stable condition on Monday, according to a hospital spokesperson.

After more than four hours Sunday, firefighters extinguished the last of the smoldering spots and were able to clear the scene about 8:30 p.m., the chief said.

Twin Rivers officials confirmed Monday that there was a “small fire at the mill” that was quickly contained, with “no significant damage.”

The fire started at a part of the machine where paper dust collects, Soucy said. The machine was in operation at the time of the fire, according to the chief.

“Sooner or later, these things happen,” he said.

Dave Deger, vice president of strategy and marketing for the mill, said in a news release issued Monday, “The root cause is still under investigation at this point.”

Acadian Festival activities in Madawaska did not impede firefighters’ access to the mill, according to Soucy.

In all, 36 firefighters from the three responding fire departments, including from Frenchville and Edmundston, New Brunswick, assisted at the scene, Soucy said.