As summer hits its peak with rising temperatures in the northern hemisphere, it is critical to keep workers safe by taking precautions to limit heat stress.
As with all hazards, employers have a duty of care to protect their employees from the dangers of heat exposure. To do that successfully, ensure you are familiar with these terms …
What Can Happen?
The National Institute for Occupational Safety and Health (NIOSH) identifies six types of heat-related illnesses, fully defined here with symptoms and treatments. Here are the basics:
- Heat Stroke: The body’s sweat mechanism fails and the body becomes unable to regulate its temperature. Body temperature can rise above 106 degrees Fahrenheit in just 10-15 minutes, leading to permanent disability or death if not immediately treated.
- Heat Exhaustion: The body overheats, losing large amounts of water and salt through excessive sweating.
- Rhabdomyolysis: Through prolonged physical exertion in the heat, muscles break down and release proteins and electrolytes into the blood, damaging the heart and kidneys.
- Heat Syncope: Signs include fainting or dizziness as a result of exposure to heat, often caused by dehydration or improper acclimatization.
- Heat Cramps: The body’s loss of water and salt through sweat leads to muscle cramps, pain, or spasms.
- Heat Rash: Skin becomes irritated from excessive sweating in hot temperatures.
How Hot is It?
Because of the potential damaging effects of these illnesses, it is important to be aware of just how hot a worksite is. The air temperature is not the only factor to keep in mind when determining the potential for heat stress. You also want to consider:
- Heat Index: Sometimes referred to as the “feels like temperature,” this accounts for air temperature combined with relative humidity. The heat index may be significantly higher than the air temperature if the humidity is great.
- Wet Bulb Globe Temperature: The WBGT goes even further, accounting not only for temperature and humidity, but also wind speed, sun angle, and cloud cover. This requires a WBGT monitor on the jobsite but produces the most accurate measurement of actual heat. OSHA’s WBGT calculator can provide an estimate.
Preventing Heat Stress
Being aware of the heat is the first step. Then you must work to limit its effects. In addition to providing ample water (one cup every 20 minutes), rest, and shade, there are procedural steps you can take to mitigate heat stress:
- Acclimatization: Gradually allowing workers to adjust to the heat, this method raises their workload incrementally, starting at 20 percent of normal duration and increasing by 20 percent or less each day.
- Modification: You can limit exposure to heat by moving more physically demanding work to cooler times of the day and rotating shifts.
- Monitoring: Be watchful for heat stress signs and symptoms such as headache, nausea, dizziness, weakness, or confusion.
OSHA and NIOSH offer a Heat Safety Tool app to help you plan your outdoor work activities, based on real-time heat index and hourly forecasts. The app also offers location-specific risk levels, recommendations for proper precautions, and a full listing of the signs and symptoms of heat-related illnesses.
For more recommendations, resources, and training guides for workers and employers, visit OSHA’s Heat Illness Prevention page.
BCSP collaborates with OSHA to keep workplaces safe as part of the BCSP-OSHA Alliance and also partners with NIOSH to improve occupational safety and health.