Ways to Protect Your Workers from Occupational Heat Stress

Categories: Safety TipsPublished On: August 7, 2023
An Occupational Worker Suffering From Heat Stress In Ontario Canada

This summer we can’t get away from all the references to heat; forest fires, climate change, and scorched days. With temperatures rising, heat stress needs to be the forefront of every employer and employee’s mind. Workplace hazards are defined as any potential source of harm to employees and the summer season brings a wide array of potential workplace hazards relating to the increased temperatures.

Summertime in Canada is fleeting but the long-lasting medical effects that heat stress can cause are not. It is imperative that employers are vigilant in identifying heat-related occupational hazards before they result in lifelong problems. Remember that as we age, and with certain health conditions, workers can be more susceptible to heat-related illnesses.

Are your employees at risk from heat stress?

Heat stress is a type of physical hazard that can cause significant harm to individuals without direct contact. Human beings have a normal body temperature of approximately 37 degrees Celsius. A sharp increase in body temperature caused by working in warm temperatures can decrease body functions.

Heat stress and dehydration go hand in hand as environmental and physical factors impact hydration levels while on the job. The Ministry of Labour, Immigration, Training and Skills Development’s Heat Stress Guideline identifies direct sunlight, humidity, and proximity to the heat source as potential causes of heat stress.

Individuals in vulnerable sectors are more likely to be working in heightened temperatures or exposed to direct sunlight and humidity for long periods of time and as a result, their systems become overloaded. Workplaces at risk of heat stress illness include:

  • outdoor settings like construction, wildland firefighting, agriculture, and landscaping, where employees are directly exposed to high temperatures and sun;
  • industrial environments with heat-producing machinery or furnaces; commercial kitchens and restaurants with hot cooking equipment;
  • warehouses lacking proper ventilation;
  • mining and drilling operations in extreme conditions;
  • firefighting and emergency response personnel;
  • agricultural work during harvest seasons; transportation jobs without adequate cooling;
  • and indoor workplaces with high temperatures due to insufficient cooling systems.
A Worker Affected By Heat Stress

The effects of heat stress

In many workplaces, occupational exposure to heat stress occurs frequently. Short-term heat stress can cause the following severe reactions:

Dehydration: Dehydration occurs when you are not consuming enough fluids to replenish fluids lost when perspiring. Symptoms include strong thirst, dry mouth, fatigue, dizziness, and dark urine.

Heat rash: This occurs when perspiration is limited due to blocked sweat glands. Symptoms include swelling and skin irritation.

Heat cramps: This occurs during the process of perspiration. The body loses salt when sweating and when that salt cannot be replaced heat cramps occur. Symptoms include muscle cramps.

Heat exhaustion: This occurs when the body is no longer able to send blood to organs, such as the skin, to cool down. Symptoms include feeling weak, nausea or vomiting, fairness or fainting, dizzy spells, headaches, breathlessness, and difficulty working.

Heat stroke: This occurs when the body’s core body temperature rises to 40 degrees Celcius. Symptoms include confusion, altered behaviour, loss of consciousness, convulsions, and lack of sweating. If left untreated, heat stress can lead to organ failure and other serious complications.

Sunburn: Working outdoors can also lead to sunburns. Sunburns occur when individuals are exposed to direct sunlight without proper UV protection. Symptoms include blistered, red, and peeling skin. Repetitive sunburns can lead to skin cancer.

How to protect your workers from the effects of heat stress:

The most efficient way to control heat stress is at the source. Engineering controls can include:

  • Reducing heat gain through proper ventilation, lowering of the air temperature, and increasing air speed by using fans
  • Ceasing heat exposure through insulation and reflective shields
  • Increasing sweat evaporation using air conditioning

If engineering controls are not possible to implement, various administrative controls can be implemented. These controls can include:

  • Acclimatizing employees to the environment they are going to be working in
  • Implementing a work-rest schedule to lessen the amount of time exposed to the heat source
  • Providing employees with insulated water bottles and promoting the consumption of 600ml to 1 litre of water each hour during the summer months.
  • Training so that workers are able to identify signs of heat stress and adequate hydration
  • Implementing a buddy system, to help co-workers recognize initial signs of heat illness
  • Water! Water! Water! The Centre for Disease Control and Prevention offers excellent information on how to stay well hydrated.
  • Proper personal protective equipment in the form of loose-fitting clothing, wide brimmed hats, sunglasses, and SPF 30

Important tip to recognize when you are getting dehydrated

Health & Safety Professionals Inc. (HSPI) is led by nurses, and we would be remiss if we didn’t share very important health information to help workers. We all learn this in nursing school!

The color of your urine can be an indicator of your hydration status. Generally, if you are well-hydrated, your urine should be pale yellow. The shade of yellow can vary from light straw-like yellow to a slightly darker, but still pale, yellow. This indicates that your body is getting enough fluids, and you are likely adequately hydrated.

On the other hand, if your urine is dark yellow, amber, or even brownish in color, it may indicate that you are dehydrated, and your body needs more fluids. In such cases, it’s essential to increase your water intake.

It’s worth noting that certain foods, medications, and vitamins can also affect the color of urine, so it’s essential to consider other factors as well, such as how often you urinate, the volume of urine, and any other symptoms you may be experiencing.

Remember that staying well-hydrated is crucial for overall health, and it’s generally recommended to drink water regularly throughout the day, especially in hot weather or during physical activity. However, individual hydration needs can vary, so it’s best to listen to your body and drink when you feel thirsty to maintain proper hydration.

How Health & Safety Professionals Inc. (HSPI) can help

HSPI can assist you in setting up a Heat Stress Prevention program, specific to the risks you face at work. We are also available for training on your program, or any of the topics in this blog. Remember, we are led by nurses, and are well suited to support your workplace.

HSPI offers a Heat Stress and Cold Stress Part Two module for certified members of joint health and safety committees. This module can be adapted to suit any workplace.


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