Firefighters were called to Oakville High School Tuesday afternoon to remove a hazardous substance out of an abundance of caution, the school district said.

Materials for science laboratories are stored in a special room at the high school at 5557 Milburn Road in Oakville, and teachers check on those materials every day, Mehlville School District Communications Director Jessica Pupillo said.

During the daily check of the room after students were already dismissed Tuesday, the teacher noticed that the room was warm and that a package of ethanol was expanding.

“Out of an abundance of caution,” Pupillo said, the school called the Mehlville Fire Protection District for assistance removing and venting the ethanol.

“All students and staff are safe. There has not been a leak of any hazardous materials. We appreciate Mehlville Fire Department’s assistance this afternoon,” Pupillo wrote in an email.

A call that went out on the scanner asked for assistance at Oakville High School with a hazardous substance or explosive materials, which may have made the incident seem worse than it was, Pupillo said.