Heat exposure in the Canadian workplace

Area of Science:

• Occupational Health and Safety
• Environmental Science
• Climate Change Adaptation

Background:

• Excessive heat exposure is a significant physical hazard for Canadian workers.
• Climate change is increasing the frequency of heat waves, posing new challenges to workforce health.
• Current Canadian labor codes rely on Threshold Limit Values (TLVs) based on Wet Bulb Globe Temperature (WBGT) to manage heat stress.

Purpose of the Study:

• To evaluate the strengths and limitations of current heat stress assessment tools used in Canadian workplaces.
• To highlight the need for improved predictive capacity in heat stress indices.
• To inform the development of more individualized heat stress risk assessment tools.

Main Methods:

• Analysis of existing Canadian labor codes and guidelines for heat stress management.
• Review of the scientific basis and application of Threshold Limit Values (TLVs) and Wet Bulb Globe Temperature (WBGT).
• Examination of the limitations of current WBGT systems in accounting for individual worker factors.

Main Results:

• Current TLVs based on WBGT have severe limitations as they generalize personal factors like clothing and metabolic heat production.
• The WBGT system primarily evaluates environmental parameters, with simple correction factors for generalized groups.
• Existing systems may lead to preventable measurement errors and suboptimal utilization in workplaces.

Conclusions:

• Improved awareness of the strengths and limitations of TLVs and WBGT is crucial for minimizing measurement errors.
• Further development is needed to enhance the predictive capacity of heat stress indices.
• Ongoing work, particularly in the European Union, aims to create improved, individualized heat stress risk assessment tools.