A small fire at the High Liner Foods plant in Lunenburg prompted a brief evacuation on Monday morning.
Fire crews from Lunenburg, Mahone Bay, Dayspring and Bridgewater raced to the Shore Road plant just before 11 a.m. to investigate reports of smoke coming from the building.
"It looks like it's associated with some roofing work that was being done on the plant," said Lee Obritsch, the vice-president of plant operations.
"We were having tar put on and it appears that some hot tar may have caused some spontaneous combustion on some insulation in a pipe and it is now under control."
Obritsch said employees were allowed back in the plant after a couple of hours and he expects everything will be cleaned up and running by Monday evening.
"There were some panels removed to get at the insulation and make sure that they had it fully under control and there was some smell and smoke," he said.
"That's why we're going to take the day to make sure we air the plant out properly before we get back up and running again."
No one was injured.