Dan Day, a school spokesman, says employees were told to leave the central New Jersey campus just before 10:30 a.m. Tuesday.
No classes are in session, although some summer programs are. In a message posted to Twitter, school officials wrote regular classes were over, graduation was last week and that the majority of students had already left for the summer.
(The Associated Press contributed to this report.)
ABC7Chicago.com will update this developing story as more information becomes available.