More than 400 Messiah College students are back in their dorms after they were evacuated for high carbon monoxide levels.
Three dorms in the Mountain View complex were evacuated shortly before 11:30 p.m. Thursday.
Campus officials believe there was a clog in an air vent.
Emergency crews were able to fix the problem. Once the levels dropped, students were allowed back in within an hour.
"Initially we thought it was a drill and then they said 'no guys, this is actually serious," said Jordan Twitchell, student body vice president. "And then everyone kind of respected that I think, so I was really proud of the population here at Messiah for the way that they responded."