The CSST has been called in to investigate after an employee suffered a heart attack on a construction site in Cote des Neiges. The 27 year old man later died in hospital.
Urgences Sante says another man was checked out and given the all-clear after he too started complaining of chest pains.
The workers were removing asbestos from a school on Dupuis street.
The presence of the mineral on the scene meant several emergency workers had to go to hospital as a precaution for decontamination after being exposed to the product.