LEWISTON — Lewiston officials say a car left running in a garage was the source of a carbon monoxide leak that sent nearly a dozen people to the hospital.

A building that houses Bernard’s School of Hair Fashion was evacuated on Thursday after a number of students showed symptoms of exposure to high levels of carbon monoxide.

The city’s fire department said three people were taken by ambulance to Central Maine Medical Center and eight others were able to drive themselves to the hospital. All are expected to recover.

The leak was traced to a vehicle that had been left running in a garage attached to the building.

The school is expected to reopen on Friday.