The Prince George's County Fire department is investigating a "small adverse chemical reaction" in the University of Maryland Chemistry Building on Thursday.
One person in the lab suffered injuries to the "facial area" and will be transported to the hospital for treatment, fire department spokesman Mark Brady said, after a chemical reaction broke a glass bottle.
Any byproduct from the reaction has disappeared, Brady said.
Michelle Obijekwu, a senior kinesiology major, said she saw two people escort another individual out of the building at about 2:10 p.m. as she was walking by.
"He kind of looked like he was in pain," she said. "He wasn't saying anything, but you could tell he was in pain."
Two emergency responders took the individual to the Regents Drive Parking Garage, where he was put on a stretcher and then into an ambulance, she said.
University Police spokeswoman Sgt. Rosanne Hoaas said in a message at about 3:13 p.m. that the building and roadway were back open.
This post will be updated as more information becomes available.
Senior staff writer Carly Kempler contributed to this article.