The document discusses fire and explosions in occupational health and safety. It outlines several key points: 1. The occupational health and safety act has provisions dealing with fire and explosion risks in the workplace. Employers must institute inspection and testing systems if volatile substances may be present. Any hazards must be removed or controlled. 2. There are five classes of fires (A-D) that present risks in different contexts. Different fire extinguishers are used depending on the class. 3. Explosions can occur through natural, chemical, nuclear, electrical, astronomical, or mechanical means. Each type presents unique dangers and precautions must be taken to prevent fires and explosions in occupational settings.