Investigators are looking into the cause of a small explosion at a Newmarket auto parts factory that sent six 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.

All six were discharged from hospital by late Wednesday afternoon, according to the company.

The factory was evacuated after the explosion, but employees were allowed to return when investigators cleared the scene in the afternoon.

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

In a written statement, Magna said the "arc flash explosion" was isolated to one manufacturing line.

Magna said its health and safety team is evaluating the manufacturing line to ensure that it is safe for employees.

“We do not anticipate any impact or disruption to our customers, nor was there any equipment and/or structural damage as a result of today’s incident,” Magna said.

York Regional Police and Ministry of Labour officials were called in to investigate the cause of the explosion.

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

@ChrisKitching is on Twitter. For instant breaking news, follow @CP24 on Twitter.