ST. PAUL, Minn. — Three buildings at the University of Minnesota have reopened after a chemical leak sent seven people to the hospital.

Campus police say 5 gallons of potassium hydroxide leaked from a large tank late Monday at a veterinary diagnostic lab on the St. Paul campus. The cause of the leak is under investigation.

The lab and two other veterinary buildings were closed due to the spill. St. Paul Fire Marshal Steve Zaccard (ZAK'-kurd) says only the room where the leak occurred remained closed Tuesday.

The seven people injured were treated for eye irritation.