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Understanding and Managing Heat Stress in the Workplace

Jul 3, 2024 | HR Tips

Summer’s arrival brings not just sunshine and vacations, but also a significant threat to worker safety: heat stress. This serious occupational illness can have both immediate and long-term health consequences, impacting not only your employees’ well-being but also your business’s productivity and potential liability. As an employer, understanding heat stress and taking proactive measures to prevent it is crucial.

While only certain jurisdictions have specific temperature limits for heat stress, it is a known hazard and falls under an employer’s general duty clause to take every precaution reasonable in the circumstances for the protection of a worker. This would include being aware of the dangers of heat stress and taking action to prevent it. 

What is Heat Stress?

Heat stress occurs when the body is unable to cool itself down effectively. This can happen due to high temperatures, humidity, physical exertion, and even certain clothing choices. Some symptoms of heat stress include:

  • A high body temperature (above 40°C)
  • A fast pulse
  • Headache or dizziness
  • Passing out/unconsciousness
  • Weakness, confusion, or acting strangely
  • Hot, dry, red skin (classic heat stroke) or profusely sweating (exertional heat stroke)

When the body overheats, it can lead also to a range of health problems, including:

  • Heat exhaustion: characterized by heavy sweating, weakness, dizziness, nausea, and headache.
  • Heat stroke: a medical emergency with symptoms like high body temperature, confusion, seizures, and coma.
  • Heat rash: red bumpy rash with severe itching.
  • Heat cramps: muscle pain in overworked areas such as arms, legs or stomach caused by a salt imbalance from heavy sweating. This can happen at work or later at home. 
  • Fainting: decreased blood flow to the brain due to inadequate fluid intake. Before losing consciousness, some employees may not experience any warning symptoms but the common signs may include cool, moist skin and a weak pulse.

Causes of Heat Stress

Heat stress can be exacerbated by several factors:

  • Direct Sunlight: Working outdoors in direct sunlight during summer months.
  • High Humidity: Workplaces with humidity levels exceeding 50%.
  • Specific Work Environments: Industries such as foundries, smelters, chemical plants, bakeries, and commercial kitchens.
  • Deep Mines: Especially those with geothermal gradients and equipment radiating heat. 

The Impact on Workers

Heat stress doesn’t just make workers uncomfortable; it can significantly impact their safety and performance. Here’s how:

  • Reduced alertness and concentration: Workers suffering from heat stress are more prone to errors in judgment and accidents.
  • Increased fatigue: Excessive sweating leads to dehydration and fatigue, hindering productivity.
  • Higher risk of injuries: Heat exhaustion can impair coordination and balance, increasing the risk of falls and other injuries.
  • Leads to more severe illnesses: Heat stress can lead to heat stroke, requiring hospitalisation and lost time while they recuperate. 

Your Role in Prevention

The responsibility for preventing heat stress falls squarely on your shoulders as the employer. Here are some examples of what you can do to keep your workplace cool and your employees safe:

  • Develop a Heat Stress Prevention Program: Create a clear plan outlining procedures for hot weather events.
  • Monitor temperatures and humidity: Regularly monitor the workplace environment and adjust work practices as needed.
  • Hydration breaks: Encourage frequent water breaks and provide easily accessible cool water throughout the workday.
  • Acclimatization: Implement a gradual acclimatization program for new or returning workers exposed to hot environments.
  • Work scheduling: Adjust work schedules to avoid peak heat hours whenever possible.
  • Proper clothing: Encourage workers to wear loose-fitting, lightweight, and breathable clothing.
  • Work tasks: Schedule strenuous tasks to cooler times of the day.
  • Provide shade and air conditioning: When possible, utilize air-conditioned spaces or provide shaded areas for workers to rest and cool down.
  • Training and communication: Regularly train employees on heat stress recognition, prevention strategies, and emergency procedures.
  • Buddy System: Implement a buddy system for mutual monitoring.
  • Workplace Policies: Assess job demands and implement protocols for hot days. 

Creating a Heat Stress Prevention Program/Plan

Employers should develop a comprehensive heat stress control plan tailored to their workplace environment which should include the following:

  • Consultation: Involve your health and safety committees or representatives in plan development.
  • Guidelines: Follow industry standards and local regulations for heat stress management.
  • Emergency Preparedness: Establish procedures for responding to heat-related illnesses promptly.
  • For seasonal heat, create a simplified plan for use between May 1 and September 30. Implement it when the humidex reaches 35 or the temperature exceeds 30°C with a humidex of 40. Also consider using the plan during heat waves or smog alerts.

As we described in our monthly newsletter for June, the Occupational Health Clinics for Ontario Workers (OHCOW) has unveiled a comprehensive Heat Stress Toolkit aimed at helping workers mitigate the risks associated with heat stress.

Key components of the toolkit include:
  • A new Heat Stress Calculator for both indoor and outdoor settings
  • An updated Heat Stress Awareness Guide
  • Two new booklets: Heat Stress Prevention Tools and Strategies and a Heat Stress Physiological Monitoring Guide
  • Posters, videos, and easy-to-understand infographics

Try the Heat Stress Toolkit

Remember, heat stress prevention isn’t a one-time effort. By proactively implementing these measures and fostering a culture of heat safety awareness, you can protect your employees’ health, well-being, and productivity throughout the summer season.

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