A faulty sensor was the cause of a hazmat scare at the University of Central Florida’s main campus after officials were alerted to a possible leak at one of the buildings.

School officials sent out an emergency message Sunday afternoon warning students of a “potentially hazardous situation at CREOL [The College of Optics and Photonics] building.”

Orange County fire officials evacuated the building as they tried to determine the source of the leak. After a few hours of searching, officials determined this was just a faulty alarm that had been activated, according to Local 6.

All operations on the campus are now normal and the building has reopened.