LINCOLN, Maine — A sprinkler system helped save a Main Street wood mill from extensive damage in a nagging fire that took about three hours to contain on Tuesday.

No injuries were reported, firefighters said.

Passers-by reported the fire at about 4:20 p.m. at LMJ Enterprises, 431 Main St., police said. The mill’s screening equipment and some other machinery at the east end of the main building were destroyed, Lincoln fire Capt. Bob Bean said.

The mill, which makes wood shavings for animal bedding, would have taken heavy damage had the flames been carried by the mill’s conveyer belts from the screening equipment into the mill’s attic area, Bean said.

“The fire did not get into the mill,” Bean said Tuesday. “The sprinkler system kicked in, and that bought us enough time to get a handle on it.”

Investigators from the state fire marshal’s office will probably investigate the blaze on Wednesday. The extent of the damage and the likely value of the equipment lost made calling the investigators necessary, Bean said.

The screening equipment separates shavings from sawdust, a millworker said.

Lowell and Mattawamkeag firefighters helped contain the fire as Burlington firefighters covered Lincoln during the emergency, Bean said.