ROCKLAND, Mass. (AP) — Firefighters in Massachusetts were called to a high school science classroom to remove an old jar that held potentially explosive sodium.

The Boston Globe reports firefighters responded to the North River Collaborative School in Rockland Tuesday morning after a science teacher found two pounds of sodium inside a jar while cleaning out a filing cabinet. Officials say the teacher wasn't sure how to dispose of the chemical.

Sodium can explode when it comes in contact with water or air.

A hazmat team and the Massachusetts State Police bomb squad helped transport the chemical to a recycling center where it was blown up. Officials believe the jar had been in the classroom for over 20 years.

School officials say the sodium posed a low threat but that officials were being cautious.

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Information from: The Boston Globe, http://www.bostonglobe.com