The Ontario Ministry of Labour is investigating two separate incidents in south Ottawa where workers were injured on the job.

The first happened a little after noon when a reported dust explosion injured a 46-year-old man.

Ottawa fire officials reported a fire in a factory warehouse at 5663 Doncaster Rd. and said it was evacuated after a possible explosion.

About 25 firefighters extinguished the blaze and about a dozen emergency workers with the Hazmat team were called in as a precaution.

The man was treated by paramedics for second-degree burns to his torso and third-degree burns to back and legs. He was then transported to hospital in critical condition and has since been upgraded to serious condition.

The factory is run by Masterloy Products Company, which makes iron alloys.

The explosion is believed to be the cause of the fire, but an investigation is ongoing, according to Ottawa fire spokesman Marc Messier. Damages are estimated at $110,000.

Firefighters completed the building search and confirmed an all-clear for people inside. The Hazmat team also investigated and cleared the scene.

About an hour later, a 37-year-old man had part of his index finger and the tip of his middle finger amputated while working on a backhoe engine just south of Barrhaven.

Paramedics treated the man before transporting him to hospital in stable condition.