An explosion at the University of Northern Iowa early Sunday caused some damage to a commons area between two dormitories. An official says it was an electrical transformer that apparently overloaded and blew up, causing a fire between Dancer Hall and Bender Hall. Dave Zarifis (ZAR-ah-fiss) is associate director of Public Safety at U-N-I. He says it’s unclear what caused the blast. Zarifis says crews are working this morning to repair the damage and hope to have it all fixed before students return from winter break next month. Students are due to return to U-N-I on January 9th. Dancer & Bender are home to several hundred students.