No one was injured when a leak of a poisonous refrigeration chemical caused the evacuation Wednesday of the Barber Foods plant on St. John Street.

The Portland Fire Department was working to shut off the leak of freon that sent workers scrambling out of the building, said Fire Capt. David Nichols.

The fire department shut down St. John Street to address the issue.

It was unknown what caused the leak.

Freon is a type of fluorinated hydrocarbon used in refrigeration and as an aerosol propellant. It can cause lung and other organ damage if breathed.