A Drew University dorm was evacuated at about 2 a.m. Wednesday after a carbon monoxide alarm went off in the building.
Five students who reported feeling ill during the evacuation were taken to Morristown Medical Center as a precaution, a school official said. They were treated and released.
PSE&G traced the source of the problem to a first-floor hot water heater in the dorm, Foster Hall, Drew spokesman David Muha said in an email.
The water heater was turned off, the building was vented and students returned to their rooms at about 3:45 a.m. after readings taken by PSE&G and the Madison Fire Department showed the air was safe, Muha said.