Abstract
Background: As mines extend deeper, workers are exposed to hotter underground environments, increasing their risk of heat-related injuries. Rising global temperatures also exacerbate the risk of heat-related illnesses on surface sites (e.g., open-pit mines). Together, workers within the mining and metallurgical industry are routinely exposed to hot working conditions. Workplace heat-related illnesses have serious ramifications across all levels of the industry. 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. Thus, this study aimed to understand how Canadian mining and metallurgical workers perceive and manage heat stress.
Methods: We conducted an exploratory web-based survey among mining and metallurgical workers (male n=83; female n=14; unknown n=2) across Canada between November 2021 to September 2022. Participants (39 (SD 11) years) represented 21 ISCO-08 classified occupations working in six sectors of the industry, including underground mining (n=48), exploration (n=24), smelting (n=11), open-pit mining (n=10), and milling (n=3). The workforce representatives completed 74 questions within four categories: workplace demographics and occupational descriptors, self-directed heat-mitigation practices and current workplace management practices, worker vulnerability to heat, and heat strain risk. Heat strain risk was determined using an adapted version of the workplace ‘Heat Strain Score Index,’ composed of 18 questions evaluating heat stress and categorizing respondents’ risk of heat strain (low, moderate, high).
Results: Heat stress was identified as a significant problem by 88% of workers surveyed. Overall, 48% of workers indicated that they are exposed to heat stress each shift, and 46% indicated that exposure durations exceed at least five hours per day. Nearly half (42%) of respondents indicated that they have been in scenarios where they were unable to modify their work effort or remove themselves from the source of the heat stress, citing a lack of a cooler area to work or rest in (18%) or time pressure to complete the task (17%) as the most common reasons. Workers reported relying on various self-management practices for heat stress mitigation, including drinking water (81%), taking regular breaks (65%), and resting in an air-conditioned space (40%). In addition to self-management, the workers reported various supervisor and safety manager enforced practices to mitigate heat stress, such as implementing regular breaks (73%) and providing training on heat illness prevention and awareness (62%). Despite these mitigation efforts, 79% of respondents reported having experienced signs or symptoms of heat stress, and 56% self-reported having experienced a heat-related illness while at work. Based on the Heat Strain Score Index, 24% of respondents were classified as high risk for heat illness, whereas 41% were at moderate risk and 35% were at low risk.
Conclusion: The findings of this survey indicate that many workers experience environmental heat stress and symptoms of heat-related illnesses, despite employing heat-mitigating behaviours. Thus, current management strategies may not adequately protect workers. With rising global temperatures, standardized, evidence-based heat management programs are needed to safeguard worker health and safety in all sectors of the mining and metallurgical industry.