Someone threw a glass filled with formaldehyde in a south stairwell at Lincoln High School, causing part of the school to be evacuated late Thursday morning.

Officer Katie Flood said it happened shortly before 11 a.m. Three or four staff members went to a health facility to be checked out after they came in contact with the chemical, which is often associated with biology class dissections.

Contact with formaldehyde can be severely irritating to the eyes and can cause coughing, nausea and shortness of breath, according to the National Institute for Occupational Safety and Health.

Flood said the south end of the school was evacuated. Police planned to interview more students to determine what happened.