DIXFIELD – A fire Wednesday morning at the Irving Forest Products sawmill in Dixfield forced the evacuation of a shift of 40 workers, none of whom was injured, mill and fire officials said.

It also shut down two sections of the complex, the sawmill production and maintenance section, that will be closed until the beginning of next week.

Additionally, the fire blew out a transformer in the planer mill, affecting 50 more employees from roughly 2 shifts, J.D. Irving spokeswoman Mary Keith said by phone late Wednesday afternoon from St. John, New Brunswick.

The planer mill is where rough lumber is sanded smooth and finished.

The planer mill employees will be out of work until Thursday evening, but 28 of the 40 from the sawmill will be out of work until Monday, May 12, when that portion of the mill is expected to resume operations, Keith said.

“Twelve of the 40 will be working to get the mill ready to run by Monday, but the others, unfortunately, will be out of work until then,” she said.

The mill employs 220 workers.

Mill officials were still assessing damage late Wednesday afternoon and trying to determine a cause for the 9 a.m. fire at 24 Hall Hill Road.

Dixfield fire Chief Scott Dennett said Wednesday morning that the fire started near a motor to a conveyor in the sawmill, which is toward the rear of the sprawling complex that consists mostly of large metal industrial buildings.

Keith said the equipment where the blaze began is called a board edger, which shaves edges of boards enabling the mill to produce square-edged lumber. It’s located near the boiler room.

The planer mill is in an adjacent building.

The fire then spread to the sawmill building’s second level, where flames activated a sprinkler system on the third floor, Dennett said.

Sprinklers kept the fire at bay, allowing interior attacks by several of the 60 firefighters who responded from Canton, Dixfield, East Dixfield, Mexico, Peru and Rumford. By 9:30 a.m., the blaze was contained.

“Sprinklers had the majority of it knocked down,” Dennett said. “There was a lot of smoke showing initially outside of the building and a lot of fire inside the building.”

Mill employees began assessing the damage by 11 a.m. after all hot spots were extinguished.

Neither Keith nor Dennett knew any damage estimates, but Dennett said the most damage was caused by water to machinery, much of which is computerized.

Protecting the mill was the reason behind the unusually large response by firefighters. Dennett said he was worried that had the fire grown larger, it could have spread to other parts of the mill complex. Strong winds were blowing through the area at the time.

“It’s a high value property … It’s an important business to the town, and we definitely want to preserve it as much as possible,” Dennett said.

“There were six fire departments there and we certainly appreciated their help,” Keith added.