Abstract
The Ontario Ministry of Labour, Immigration, Training and Skills Development recently proposed a new regulation within the Occupational Health and Safety Act (OHSA) to specifically address workplace heat stress. Similarly, an amendment was filed within the Mine and Mining Plants Regulation of the Ontario OHSA requiring that all sites develop and maintain written procedures for managing heat stress. While heat-specific legislation is a step in the right direction, there are critical limitations in the proposed changes and current guidance. For example, current guidance advocates employing the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values to prevent core temperature from reaching potentially unsafe levels (e.g., >38°C) through use of heat-mitigation controls (e.g., work/rest). However, these guidelines do not stipulate how long work can be conducted before controls should be employed. This is a significant concern since employing heat-mitigation controls too early will reduce productivity and performance, but controls applied to late will be ineffective for protecting worker health and safety. To address these knowledge gaps, our laboratory, in collaboration with the Ontario Workers Safety Insurance Board, and industry and union partners, is leading a vital series of projects that will help advance the knowledge necessary to equitably protect the health of all workers labouring in the heat.
Part 1: Laboratory-Based Work Simulations in the Heat
The first set of studies employs a laboratory-based work simulation developed based on field evaluations of workers performing duties in hot environments (e.g., miners). The simulations will allow us to generate estimates of safe, initial stay times before heat-mitigation controls should be applied in healthy male and female, young and older, workers performing moderate- and high-intensity work in the heat. Further, we will determine whether using heat-mitigation controls (e.g., work/rest) following these initial stay times prevent rises in core temperature beyond recommended limits (i.e., 38°C) during a moderate intensity, day-long work shift and on the next consecutive workday.
Part 2: Knowledge Mobilization and Guidance Development
Information gleaned from Part 1 will be used to generate a reference table delineating safe initial stay times for work in hot environments and the associated heat-mitigation controls that the industry can implement (e.g., work/rest, hydration). However, we are conducting a second series of work simulations to ensure that the guidance developed is industry-appropriate and relevant and supports knowledge users (i.e., OHS managers, JHSC) to make site- and worker-specific informed decisions. First, we are seeking to understand what current heat management guidance is available to workplaces across Canada via a content analysis of educational resources and materials published online by OHS agencies and industry associations. Next, we are conducting interviews with OHS representatives to identify the challenges experienced with heat management and to determine any positive enablers or modifying factors (e.g., safety culture). Lastly, we are developing a questionnaire to evaluate OHS representatives' current heat stress knowledge and help support our understanding of the current training needs of industry partners in applying heat management guidance.