Investigators are looking into the cause of a small explosion at a Newmarket auto parts factory that sent at least five workers to hospital Wednesday morning.

The victims suffered non-life-threatening injuries in the explosion at a Dortec Industries plant on Newpark Boulevard, near Bayview Avenue and Mulock Drive, an EMS spokesperson told CP24.

The incident occurred shortly before 9:40 a.m. and was not followed by a fire, said Central York Fire Services Chief Ian Laing.

In total, nine workers were injured and six were taken to hospital, according to fire and EMS officials.

The factory was evacuated after the explosion.

Dortec Industries, a division of Magna International, manufactures door latches for vehicles at its Newpark Boulevard plant.

In a written statement, Magna said the incident occurred on a manufacturing line, and five employees were taken to hospital.

Magna said investigators are not allowing anyone back into the building, as of Wednesday afternoon.

York Regional Police and Ministry of Labour officials are investigating the cause of the explosion.

There is no evidence the explosion is criminal in nature, police told CP24.