One person was killed and another received life-threatening injuries during a blaze that broke out Wednesday morning at the Siltech Corp. chemical plant in Toronto, ON, local news organizations reported.

First responders were sent to the site around 9:50 a.m. for an initial report of an explosion, coverage by CBC said. Crews determined after arriving at the scene that a chemical fire was happening at the plant.

Workers evacuated the facility during the incident. Several roadways were temporarily closed during the response.

The Ontario Ministry of Labour, Training, and Skills Development (MLTSD) has assigned an inspector to conduct an investigation into the fire, according to CTV News. The cause of the fire is currently unknown.

Siltech produces a range of organo-functional silicone compounds and other silicone specialties at the Toronto plant.