Extreme heat and the worker

With global temperatures rising, heat waves are becoming the new normal, leaving many workers increasingly vulnerable to sunstroke and other heat-related illnesses, and at risk of injury from related loss of concentration and fatigue. While working in hotter temperatures impacts outdoor workers, including first responders and those in construction, agriculture and transportation, workers in indoor environments such as warehouses and factories are also at risk. As a U.S. report noted, “workers may also have less control over their exposures to climate change related risks than the general public …” – especially those in the informal economy and precarious employment.

The Institute for Work & Health (IWH) 2013 study led by Melanie Fortune was the first to look at extreme heat impacts on Ontario workers across all sectors. Using hospital emergency room records and lost-time claims data from Ontario’s Workplace Safety and Insurance Board (WSIB), researchers looked at how often work-related heat stress happens, who faces the most risk and when cases happen most frequently. Among the study’s findings: young, manual labourers new to the job are the most vulnerable. Broken down by occupational sector, data showed the public sector (government workers in outdoor work such as park & recreation services, garbage collection, forest firefighting etc.) to be at highest risk of heat stress injury, followed by agricultural, then construction and business sectors. A 2017 Quebec study documented a positive association between an increase of daily outdoor summer temperatures and the estimated daily risk of not only heat-related health problems, but also work-related accidents.

Among the increasing research on heat exposure in light of projected climate changes, a Feb. 2018 Australian study has examined the impact of sustained high temperatures on work injury. Using workers’ compensation claims data, the researchers found significant injury risk for workers exposed to two and three consecutive days of hot weather at relatively mild temperatures (27.6⁰C).

Who is protecting workers?

Legislation on temperature conditions at work varies across Canada. In some cases, legislation governs acceptable ranges in specific circumstances. In others, the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs) for Heat Stress and Heat Strain, based on preventing workers’ core body temperatures from rising above 38°C, are adopted as guidelines or occupational exposure limits.

In Ontario, legal requirements under the Occupational Health and Safety Act (s.25(2)(h)) require employers to take every precaution reasonable for worker safety including development of policies and procedures to protect those working in hot weather. For compliance, the Ministry of Labour recommends usage of the TLVs.

However a workplace safety expert is calling for new guidelines on working in the heat. Recent research, undertaken at the University of Ottawa, suggests the current guidelines on heat stress were developed for young workers and insufficiently protect all workers, especially those above 40 or with chronic health conditions.

While adequate workplace safety management can help minimize risks from extreme heat, policy action from all levels of government on climate change is needed to meaningfully address its negative health effects.

Who is protecting workers?

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