ENFIELD, CT — Students at Enfield High School were dismissed a few minutes earlier than usual Monday, following a brief evacuation due to activation of a CO detector.

The CO detector was triggered in the boiler room around 1:10 p.m., and the building was evacuated. About a half hour later, the fire chief allowed students to go back into the building to retrieve their belongings once he determined that it was safe to re-enter the building, according to a message sent to parents by Principal Erin Clark.

"Although it was safe to resume school, it was decided to end school early as a strong sewage odor was present due to the fact that the ventilation system shuts down once a CO detector is triggered. Smyth bus company was contacted and buses arrived early to school," Clark wrote.