Two graduate students and a professor were accidentally exposed to fluorine gas after a leak at about 11 a.m. Friday at Faraday West, Room 311. The leak resulted in the building and Normal Road being shut down for about two hours.

One student suffered a minor burn on the arm when fluorine gas leaked from a tank and mixed with oxygen, resulting in a “flash fire,” or sudden burst of flame, DeKalb Fire Chief Lanny Russell said.

“You don’t want to breathe [fluorine]. It’s toxic,” said Lee Sunderlin, associate professor of chemistry.

The students first were treated at University Health Service before being taken to Kishwaukee Community Hospital, Russell said.

Officials shut down the building and Normal Road from Lucinda Avenue to Lincoln Highway following the incident.

As a safety precaution, automatic ducts opened up at the response of the fire alarm, venting the fluorine gas out of the building.

Firefighters deemed the building safe to re-open about 1 p.m. Friday.