Officials at Raritan Valley Community College say a fire in a mechanical room caused the evacuation of main campus buildings and sent four people to the hospital with respiratory complaints.
Security guards discovered the fire at 8:15 a.m. Tuesday in Hunterdon Hall and quickly extinguished it.
Officials believe an overheated motor caused the fire.
Three security officers and a faculty member were taken to the hospital complaining of respiratory difficulty. There was no immediate word on their conditions.
The campus reopened at noon after power was fully restored.