With summer in full swing, employers must be wary of protecting workers from heat-related illnesses; this includes building service contractors and facility managers whose daily tasks often subject them to the outdoors.

“Working in very hot conditions is not just a matter of being sweaty and uncomfortable,” says Jan Chappel, senior technical specialist for the Canadian Centre for Occupational Health and Safety (CCOHS). “Heat stroke is a serious condition and it can be fatal without medical attention. People who are struggling in the heat are not able to see the symptoms in themselves and must rely on their co-worker’s ability to identify that there is trouble.”

Currently, there is no single maximum temperature for working or for which work should stop. At the same time, the CCOHS says employers have a general duty under Section 25(2)(h) of the Occupational Health and Safety Act to provide a safe workplace, and should take every precaution reasonable in the circumstances for the protection of a worker.

Working in extreme heat

Some provinces and territories have regulations or guidelines for working in the heat, but Chappel says that often the guidelines only cover specific situations such as an indoor space where no regulations exist. Still, not following requirements set out in regulations runs the risk of liability. As an initial step, implementing a work and rest schedule during extreme heat is advised.

“Some jurisdictions use the the American Conference of Governmental Industrial Hygienists (ACGIH) recommendations for Threshold Limit Values (TLVs) for working in hot environments,” notes Chappel. “These limits are given in units of wet bulb globe temperature (WBGT) degrees Celsius (°C). The WBGT unit takes into account environmental factors namely, air temperature, humidity and air movement, which contribute to perception of hotness by people.”

Under certain workplace conditions, the humidex may serve as an indicator of discomfort resulting from occupational exposures to heat. The Occupational Health Clinics for Ontario Workers Inc. (OHCOW) created a humidex-based response plan that translated WBGTs into humidex values and developed recommended responses for each humidex range. For instance if the humidex rises between 30- and 33-degrees Celsius, an employer should post a Heat Stress Alert notice, encourage workers to drink extra water and start recording hourly temperature and relative humidy.

All materials in the OHCOW chart should be used and followed. This chart can be found in table three under the Humidex Rating and Work section of the CCOHS website.

Signs of heat-related illness and precautions

Symptoms can vary from person to person; however, the warning signs of heat stroke can include complaints of sudden and severe fatigue, nausea, dizziness, light headedness, and may or may not include sweating.

“If a co-worker appears to be disorientated or confused (including euphoria), or has unaccountable irritability, malaise or flu-like symptoms, the worker should be moved to a cool location and get medical advice,” Chappel stresses.

The longer an employee works in a hot environment, the more he or she gets acclimatized to the heat. The Ontario Ministry of Labour says if a person is ill or away from work for a week or so, he or she can lose their acclimatization.

Those experienced on the job should limit shift time in hot working conditions to 50 per cent on the first day, 60 per cent on the second day, and 80 per cent on the third day. They should be able to work a full shift on the fourth day. For people not experienced on the job (for example, if you are a new employee), they should spend 20 per cent of shift time in hot working conditions on the first day and increase their time by 20 per cent on each subsequent day until five days go by.

Besides watching out for other workers, OHCOW suggests people wear hats and light-coloured clothing, take breaks in the shade and drink plenty of water every 15 minutes, even if they aren’t thirsty.

Extreme heat program and awareness

An extreme heat program should cover what work and rest schedule is required for various temperatures. It should also incorporate education and training for workers about the risks and health effects.

“Be sure they are aware of how heat affects a person so they can help each other,” adds Chappel. “Also, facilities should be aware that it’s more than just a hot, humid day that can be a risk for heat stress. There may be situations where a person is working in an area that is heated by hot metal, furnaces or steam pipes. When combined with poor air flow, and a high physical effort to make the repair (for example), cleaning and maintenance staff may be at higher risk.”

The CCOHS says not everyone reacts or adapts to heat the same way. These differences range from extra body weight (the body has difficulty maintaining a good heat balance) to age (particularly 45 years and older). Poor general health, a low fitness level and medical conditions also increase how susceptible the body is to extreme heat.

“People with heart disease, high blood pressure, respiratory disease and uncontrolled diabetes may need to take special precautions,” Chappel says. “In addition, people with skin diseases and rashes may be more susceptible to heat. Other factors include circulatory system capacity, sweat production and the ability to regulate electrolyte balance.”

Both management and employees should be aware of the effects of extreme heat.

“When using controls such as a work and rest schedule, management should promote that it is appropriate to pace the work—these changes may affect how many tasks are accomplished in a period of time—and workers need to understand the risks and the importance of following the schedule.”