One person is dead and others are hurt after an explosion was heard at a Toronto chemical plant on Wednesday morning.

Emergency crews were called to a plant in the area of Beth Nealson Drive and Wicksteed Avenue, north of Thorncliffe Park, at 9:50 a.m. for reports of a large explosion.

Toronto police said they arrived on scene at 225 Wicksteed Avenue, the address of Siltech Corporation, and found at least one injured person.

Paramedics said the first patient they encountered was pronounced dead after attempts at CPR were unsuccessful at the scene and one other patient, an adult male, was found suffering from serious burns and transported to hospital.

Callers told dispatchers that they heard a loud bang and then witnessed dark smoke coming from the building.

Firefighters said they suppressed the fire by using foam and there was residual smoke wafting from the building.

“These types of fires are a lot more difficult than what the public is used to because you have to pick a specific extinguishing agent in relation to the chemicals that are on fire,” Acting Fire Chief Jim Jessop told reporters at the scene.

He said suppressing the flames took a considerable amount of time.

A fire investigator was dispatched to the scene to conduct an investigation into what caused the blast.

Police also said the Ontario Ministry of Labour would probe what caused the explosion.

The plant is believed to produce silicone products.