Firefighters responded to John F. Kennedy Middle School in Southington on Friday morning after a glycol leak from the heating ventilation and air conditioning system.
Officials said a line of glycol in a second-floor science room came apart, sending glycol into a few rooms and down the drains to the first floor.
In all, about 100 gallons of glycol spilled. Officials said it is not toxic or hazardous, but the main issue was the odor.
Two classrooms on the second floor were impacted, as well the entrance to cafeteria on first floor and part of hallway.
"Unfortunately we have experienced this problem previously, but as a result we do know exactly how to deal with the situation and we know that it presents no danger to students or staff," Supt. Timothy F. Connellan said in an email to parents.
He said clean up has been underway since earlier this morning and classes will be proceeding normally.
Students are being kept away from the area impacted and were allowed into the school.
Firefighters set up fans to air out the school.
Because one of the clean up areas is near the cafeteria, the breakfast program was disrupted and students were sent to the auditorium instead of the cafeteria, according to the superintendent, but they do not believe that the lunch schedule will need to be modified.