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Heat Stress - Know The Symptoms

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Heat Stress - Know The Symptoms

McGuinty Government Urges Workers To Protect Themselves From Heat Stress

Ministry of Labour

Hot and humid summer days bring an added danger - heat stress.  Ontario has tips and information to help employers and workers learn how to protect themselves from this seasonal hazard.

When heat is combined with other stresses like hard physical work, fluid loss, fatigue or some medical conditions, it can lead to heat-related illness, disability and even death. 

Heat stress can affect anyone, including the young and fit, and can be a concern in many workplaces.  Symptoms of heat stress can include: excessive sweating, headache, rashes, cramping, dizziness and fainting.

Quick Facts

  • Workers most at risk for heat stress include those in hot environments, such as smelters, furnaces, bakeries and out of doors during the summer.
  • Prolonged exposure to heat stress can lead to heat stroke, a life-threatening condition.
  • The victims of heat stroke are often unable to notice the symptoms, and their survival may depend on co-workers' ability to identify symptoms and to seek immediate medical assistance.

Background Information

Additional Resources


“As we enter the summer season, the natural heat and humidity puts both indoor and outdoor workers at risk. All workers, be they summer students or regular employees, ought to be aware of the dangers of heat stress, and need to work with their employers to protect themselves.”

Peter Fonseca

Minister of Labour

“During Ontario summers, heat stress can be a serious hazard for construction workers, especially if they're doing heavy work. Employers should have a clear policy to protect workers from the heat. Workers should stay hydrated and watch for the signs and symptoms of heat stress.”

Doug McVittie

Assistant General Manager of the Construction Safety Association of Ontario

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