For many, the heat of summer is a welcome change from a long, cold winter. For workers and others, however extreme temperatures and humidity can lead to heat stress and related health problems.
Here in Ontario, heat stress is often a concern in the summer months for both inside and outside workers. Though heat exposure can occur year round in workplaces where sources of heat are common including foundries, bakeries, commercial kitchens and chemical facilities.
Whether working in the direct sunlight or in enclosed work spaces lacking adequate cooling systems or ventilation, heat can place undue stress on the body's natural cooling system. Excess sweating, physical work, overall fatigue or an existing medical condition can place even more stress on the body. In extreme cases, exposure can be fatal.
Under Ontario's Occupational Health & Safety Act (the Act) employers have a general duty to take every reasonable precaution to protect workers' health and safety (section 25(2)(h)). Reasonable precautions may include making water readily available, adding rest breaks or when conditions warrant stopping work. Precautions should also include developing a heat stress prevention, monitoring and control policy along with procedures to implement this policy. This should be developed in consultation with the joint health and safety committee or worker representative and have a worker training component.
Ontario Ministry of Labour inspectors rely on threshold limit values (TLVs) for heat stress published by the American Conference of Governmental Industrial Hygienists (ACGIH) for enforcing the Act’s general duty clause.
The Occupational Health Clinics for Ontario Workers (OHCOW) offers resources to help focus workplace efforts on prevention. They include a sample Humidex/Heat Stress Response Plan based on the ACGIH TLVs. They also offer a Humidex-Based Heat Stress Calculator on their web site.
The Workers Health & Safety Centre (WHSC) offers heat (and cold) stress training focused on general awareness along with workplace specific prevention strategies to eliminate exposure or mitigate the potential risk to health. The WHSC has also published a Heat Stress hazard bulletin.
Want to review the MOLs heat stress resources, including their heat stress guideline?
Want to access workplace heat stress assessment tools developed by the Occupational Health Clinics for Ontario Workers (OHCOW)?
Want to download the WHSC's hazard bulletin Heat Stress: Cool solutions?
Want to learn more about WHSC heat stress training — contact a training service representative at a WHSC office near you?