The heat waves that have gripped much of the world in June and July have also been manifest in Canada, where as many as 70 people died in Quebec (mostly in Montreal), as temperatures stayed at over 40 degrees Celsius with the humidex. Many more are likely to have died, but Health Canada does not keep statistics on heat related deaths. In their July 7 press release on the topic, the Canadian Association of Physicians for the Environment quote figures from the Climate Atlas of Canada which state: “Before 2005, Montreal had, on average, 8 days per year with temperatures over 30 degrees C. With climate change, it is predicted that Montreal will experience more than 50 days per year with extreme temperatures by 2050.” For Toronto, the prediction is for 55 days per year with temperatures over 30 degrees after 2050.
In general, public attention and interventions are normally directed to the most vulnerable in the population: the aged, chronically ill, homeless and those living alone, as in “Doctors urge population to stay cool after dozens die during heat wave in Central Canada” in the National Observer (July 10). But what about workers, who may not have the option to “cool off”?
On July 17, the U.S. advocacy group Public Citizen published Extreme Heat and Unprotected Workers , describing the state of regulation in the U.S., current and historical statistics on heat-related illness and death, particularly for construction and farm workers, the likely exacerbation of the situation due to climate change, and making the case for a federal heat stress standard. One example: The report states that from 1992 to 2016, heat killed 783 workers in the U.S. and seriously injured nearly 70,000. Based on this hard-hitting analysis, Public Citizen, along with United Farm Workers Foundation and Farmworker Justice, joined more than 130 public health and environmental groups in submitting a petition to the U.S. Occupational Safety and Health Administration, calling for the agency to require employers to protect their workers from heat by imposing mandatory rest breaks, hydration and access to shade or cooled spaces, among other measures. The report is summarized by Inside Climate News in “Heat Wave Safety: 130 Groups Call for Protections for Farm, Construction Workers ” .
In a July article in Morbidity and Mortality Weekly Report, published by the U.S. Centres for Disease Control (CDC) , researchers recommend using a heat index of 85 degrees F as a threshold for potentially hazardous worker heat stress, rather than the current U.S. standard of 91 degrees F (32.8C). They base this recommendation on a review of 25 incidents of outdoor occupational heat-related illnesses, including 14 deaths, that were investigated by the U.S. Occupational Safety and Health Administration (OSHA) between 2011 and 2016. They found a risk of illness at a heat index of just 29.4 C (85 F) – and 6 deaths happened below 90 degrees F. The authors also noted: “Employers often obtain heat index information from publicly broadcasted weather reports or forecasts that do not necessarily reflect conditions at their work sites.” Other recommendations from the article: “ a comprehensive heat-related illness prevention program should include an acclimatization schedule for newly hired workers and unacclimatized long-term workers (e.g., during early-season heat waves), training for workers and supervisors about symptom recognition and first aid (e.g., aggressive cooling of presumed heat stroke victims before medical professionals arrive), engineering and administrative controls to reduce heat stress, medical surveillance, and provision of fluids and shady areas for rest breaks.”
In Canada, Professor Glenn Kenny of the University of Ottawa is an expert on the effects of heat stress on older people, and on workers. Some of the studies on which he has collaborated: “Heat Exposure in the Canadian Workplace” (2010) in the American Journal of Industrial Medicine , in which he points out the strengths and weaknesses of the Threshold Limit Values (TLVs) based upon Wet Bulb Globe Temperature (WBGT), the standard used in most Canadian jurisdictions; “Do the Threshold Limit Values for work in hot conditions adequately protect workers?” (2016) ; and “An evaluation of the physiological strain experienced by electrical utility workers in North America” (2015) in the Journal of Occupational and Environmental Hygiene .
What are the existing heat standards for workers? A fact sheet from The Canadian Centre for Occupational Health and Safety (CCOHS), Temperature conditions: Legislation , provides a summary chart of Canadian legislation, ranging from Alberta, (which has guidelines only), to Ontario, which has the most specific standards, set out in clause 25(2)(h) of the Occupational Health and Safety Act . Also useful: CCOHS Fact Sheet: Humidex and work and Thermal Comfort for Office work. From the Occupational Health Clinics for Ontario Workers (OHCOW) – Humidex Based Heat Response Plan (2014).
In the U.S., Occupational Safety and Health Administration (OSHA) maintains a web portal for working in indoor and outdoor heat and the National Institute for Occupational Safety and Health portal on heat stress is here. NIOSH also publishes information on Hazards to Outdoor Workers which includes heat, sun exposure, vector- borne diseases by ticks, mosquitos, and a separate fact sheet for Lyme disease(none of which have been updated since 2010) . In February 2016, the NIOSH published Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments, which updated the previous version from 1986.