Working in Heat: Ontario Employer Obligations for Hot Weather Safety

Every summer, Ontario workers in construction, landscaping, agriculture, and other outdoor industries face serious risk from heat stress and heat stroke. Under the Occupational Health and Safety Act, employers have a general duty to take every reasonable precaution to protect worker health — and that includes extreme heat. While Ontario does not yet have a standalone heat regulation with specific temperature thresholds, employers who fail to protect workers from heat-related illness can face Ministry of Labour orders, fines, and liability. A proactive heat stress program is not just good practice — it's a legal obligation.