Abstract

Background: With climate change fueling an increase in the occurrence of hot weather, occupational heat stress continues to threaten the health and safety of workers in the mining and metallurgical industry. When combined with essential personal protective equipment, the risk of occupational heat stress increases. Thus, heat stress management needs to be prioritized to protect worker health, safety, and productivity. However, there is currently no industry-standard heat stress management guideline, partly due to differences in health and safety legislation and mine-specific regulations across Canada. Therefore, to better understand current heat management practices used in the mining and metallurgical industry, we conducted an exploratory web-based survey of representatives responsible for health and safety at sites across Canada, including eight provinces and one territory, between November 2021 to September 2022.

Methods: The health and safety representatives (n=55) were comprised of individuals from underground mining (n=39), open-pit mining (n=4), milling (n=4), smelting (n=3) and other metallurgical operations (n=4). Respondents completed 50 questions assessing heat management practices within six categories: workplace demographics and context, perceived heat stress risk, administration of heat stress management, heat stress emergency procedures, environmental monitoring for heat stress, and knowledge of mining-specific legislation and regulations related to heat stress. 

Results: Overall, 47% reported that heat-related illnesses lead to restricted duty or lost time claims at their site each year (3.5 ± 5.5 reportable episodes), but many (67%) also feel that heat illnesses are under-reported by their workforce and crew supervisors. Most (78%) sites have established heat stress management programs to prevent heat illness, typically based on the American Conference of Governmental Industrial Hygienists threshold limit values (69%). Just over half reported performing real-time monitoring of heat stress in the workplace (58%) or offering personnel heat strain assessments (51%). Most health and safety representatives indicated that they conducted pre-task evaluations for heat stress (59%), which were commonly based on work effort (55%), ambient temperature (47%), and/or ambient humidity (37%). However, 29% indicated that they do not complete post-job evaluations, and only 33% of site representatives reported a review evaluation is required for heat-related tasks or personnel pre-screening for heat stress vulnerability (66%). Within broader heat stress management programming, structured heat-related illness prevention techniques were common with most organizations (67%) and included various heat mitigation strategies, including the use of central or local air-conditioning (55%), acclimatization (45%), hydration regimes (45%), use of personal cooling devices/systems (16%), and insulation of hot surfaces (10%). Half of the sites (51%) also provide employees with electrolyte replacement. Lastly, when asked about health and safety or mining-specific legislation and/or regulation(s) governing workplace heat stress, half of the respondents indicated that none existed or were unsure (51%). 

Conclusion: While many companies acknowledge that heat stress is a workplace hazard and employ heat management programming, heat-related illnesses are still occurring. To maximize worker health, safety, and productivity during work in hot environments, industry-standard guidelines must be developed and applied within all mining and metallurgical industry sectors.