Prince George's County Fire & EMS spokesman Mark Brady says that people reported smelling gas Wednesday morning.
When crews arrived, they found a 4-inch high-pressure gas line break at Route 202 and Campus Way South.
All roads and nearby buildings on the campus are closed as a precaution.
Crews are now working to repair the break.
An automated phone message said all day and evening classes are canceled on the Largo Campus.
(Copyright 2010 by WTOP. All Rights Reserved.)