Neither the Science Department teacher involved nor any students or staff were injured or exposed in the incident just before 2 p.m., responders said.
Dumont Fire Chief Mark Abdulla called the incident a ventilation issue and not a spill.
Also responding were members of the Dumont Volunteer Ambulance Corps, a Bergen County Hazardous Materials Unit and a New Milford Hazardous Materials team.
Click here to follow Daily Voice Teaneck and receive free news updates.