A chemical spill in Percival Stern Hall forced students and faculty to evacuate the building for roughly six hours beginning Monday morning until the school issued an all-clear by 3:05 p.m. 

Tulane University sent an alert warning all people in the building to evacuate and avoid entering the building, and some students said they were told to leave all their belongings in the building.

One gallon of chlorine dioxide spilled in one laboratory Monday morning, Tulane spokesperson Mike Strecker said. Chlorine dioxide is often used as bleach. Exposure to the chemical can cause nose, throat and lung irritation and large exposures can cause shortness of breath and respiratory problems, according to the CDC. 

“The building was safely evacuated, although one individual in the laboratory experienced shortness of breath and was transported to an area hospital,” Strecker said in a statement. 

It is unclear if the individual was a student.

This is the second time Stern has been evacuated this school year. In September, a small amount of oil caught fire in a lab and forced students and faculty to evacuate the building. 

Tulane’s Office of Environmental Health and Safety, Tulane University Police Department, New Orleans EMS and the New Orleans Fire Department responded to Stern Monday morning. Around noon, Strecker said the spill was being cleaned and that the school would conduct a “full review” of the incident.

“There is no danger to the campus area or surrounding community,” Strecker said.