Students at Southwestern College in Chula Vista were evacuated Thursday morning after the student contacted her instructor to report why she had been absent. She told her professor she wasn’t feeling well and her sister was hospitalized after a trip to the Midwest.

As a precaution, school officials shut down one building and sent a safety alert via text to all students and staff, according to Public Information Officer Lillian Leopold.

The student was isolated, and about 50 other students and two faculty members were kept inside the building as the San Diego County Department of Health and Human Services was notified.