ORLANDO, Fla. -

The University of Central Florida Student Union was evacuated for almost two hours Monday afternoon after reports of a "pepper-spray irritant" deploying in the building, according to UCF officials.

11 patients were treated on scene with no one taken to the hospital, according to Orange County Fire Rescue. It's not clear what caused the irritant to be deployed.

Hazardous materials teams were on scene investigating as students were told to move out of the building. Local 6 news helicopter Sky 6 flew over the campus as numerous vehicles were set up around the Student Union and students gathered outside waiting to be let back in.

"The UCF Student Union has been evacuated due to reports of a pepper-spray-like irritant in the lobby area," according to a UCF alert. "UCF Police and Orange County Fire Rescue have responded to the scene, and officials evacuated the building at about 3:30 p.m. in an abundance of caution. All other campus operations are normal. "

The student union was reopened just before 5 p.m. Monday.