WATERVILLE (AP) – Operations at a MaineGeneral Medical Center building were suspended Monday following a boiler explosion that forced the evacuation of dozens of patients.

The boiler exploded shortly before 7 p.m. Sunday in the hospital’s Seton unit, blowing out windows in the boiler room and knocking out heat to the 44-bed building, said hospital spokesman John Begin.

The hospital transferred 27 patients to the hospital’s larger Thayer unit in Waterville and five patients to its campus in Augusta. Twelve patients were discharged.

The blast occurred just a minute or two after the boiler operator had checked on the furnace and left the building, Begin said.

Officers from the state fire marshal’s office and the Department of Environmental Protection were at the hospital Monday to determine the cause of the explosion and inspect for the presence of asbestos and fuel contamination.