CHICAGO (CBS) — A building at the University of Illinois in Urbana was evacuated for a couple of hours this afternoon – after some kind of chemical reaction in a lab.

No reports of people being taken to hospitals at this point – but University of Illinois Spokesperson Robin Kaler says five people in the chemistry annex had to be decontaminated.

“Apparently someone accidentally mixed two chemicals in a waste container and they had a reaction.”

Asked if there was an explosion, Kaler says she can’t confirm that but she says some people reported hearing something.

Kaler says the chemicals may have been hydrochloric acid and nitric acid.

She says the call came in to the fire department about 4 p.m.

The all-clear was given about 6 p.m.

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