The Chemistry Department at Villanova University in Pennsylvania is reviewing all protocols and procedures after a lab experiment prompted evacuation of the science building and sent nearly 30 people to the hospital on Tuesday — some with nose bleeds and many others who were having trouble breathing.

"One student fell ill, she was taken to the ladies room, they thought it was an asthma attack, then she started having nose bleeds," said Police Superintendent Bill Colarulo of Radnor Township, just northeast of Philadelphia, NBC Philadelphia reported.

The teacher who was overseeing the lab experiment then started to feel faint and other students began having adverse reactions. The most common complaints were of dizziness, nausea, breathing problems and feeling light-headed.

"There was no indication of a chemical spill or reaction," David Tedjeske, director of public safety at the university, said in a statement on Wednesday. "The experiment being conducted was a commonly performed organic synthesis using propionic acid and alcohol to create a compound. The chemistry department is conducting a comprehensive review of their protocols and procedures as the safety of our students is always our highest priority."

According to New Jersey’s Right to Know Hazardous Substance List, propionic acid is a corrosive chemical used as a preservative, fungicide, and antimicrobial agent.

Direct contact with the acid can severely irritate and burn the skin and eyes and inhaling it can irritate a person’s nose, throat and lungs, causing shortness of breath and other complications, according to the website.

"There are fume hoods in the lab and the students all wear protective gear when performing the experiment, including eye protection," said John Gust, director of media relations at Villanova. "This was a commonly performed experiment that has been run the same way numerous times before without incident."

Hazmat crews evacuated the whole science center building, and set up hazmat tents for treating affected students.

"We got evacuated, nobody was really sure what was going on," student Justin Wickersham told NBC Philadelphia. "We just thought it was a regular fire drill."

All students in the lab were contacted and asked to return to the area for evaluation, said police and university officials.

In total, 45 individuals were evaluated by Villanova and Radnor emergency responders and 29 of those were transported to local hospitals, evaluated and released.

The science building was deemed safe and reopened on Wednesday.