Most of Mason buildings are open from 8am to 10pm. Building lights are kept on for emergency egress as well as for safety reasons. However, if you believe they are unintentionally left on, please note specifics of the occurrence such as date, time, building, room number (if possible), part of the building, and floor number. You can report this information to Facilities customer service at 703.993.2525 or csc@gmu.edu 24/7.