Heat stress can occur wherever work operations involve heavy physical labour in hot, humid environments. The locations may be indoors or outdoors. Protective clothing can also contribute to the problem.

Heat stress causes the body's core temperature to rise. A series of disorders can develop, ranging from discomfort and pain (heat rash and heat cramps) to life-threatening conditions (heat exhaustion and heat stroke).

Members of the Occupational Health and Safety Council of Ontario (OHSCO) have developed a Heat Stress Kit, which includes a Heat Stress Awareness Guide, Heat Stress Awareness Tool and Heat Stress Poster to provide information and advice on managing and controlling heat stress in the workplace. OHSCO has also developed a Heat Stress Survey to help evaluate the usefulness of the kit. User feedback would be greatly appreciated.

1.  Where does heat stress occur in construction?

2.  What happens when the body's core temperature rises?

3.  How can we recognize heat stress disorders?

4.  What factors are used to assess heat stress risk?

5.  Are there measures for evaluating heat stress risk?

6.  How can heat stress be controlled?

7.  What are the responsibilities of workplace parties regarding heat stress?

OHSCO's Heat Stress Awareness Guide helps employers and workers learn how to prevent heat stress. The guide summarizes the causes, symptoms, and treatment of heat-related illness, demonstrates how to use the Humidex to assess heat stress hazards, and outlines specific actions for managing and controlling heat stress.

Includes a self-audit checklist, a sample heat stress policy, a reference chart and humidex guideline, an outline of the essential elements of a heat stress program, and useful contact information.   Disponible en français

Our Heat Stress Prevention Guide helps you put together a heat stress prevention plan that would allow workers to regulate their own pace of work, rest breaks, and fluid intake in hot conditions.

Includes a chart outlining first aid response for heat illness.

• Low-res Version – PDF file (11" x 17")
• High-res Version – TIF file (11" x 17")

• Heat Stress (from Construction Health and Safety Manual – M029)
• Heat Stress Safety Talk (from Safety Talks – V005)
• Sun Protection Safety Talk (from Safety Talks – V005)

• Environment Canada fact sheet (Summer Severe Weather Warnings)
• Occupational Safety and Health Administration (USA) (Hazards and Possible Solutions)
• Health Canada
• Environment Canada
• OHCOW Humidex-based heat stress calculator
• Environment Canada humidex calculator
• Environment Canada weather office
• Air Quality Ontario smog advisories