It’s all over the safety news right now — heat stress is finally getting the recognition it deserves for the millions of employees who have to work out in the heat every day. As we approach the summer months, we’ve got to do a better job of taking care of our personnel and watching out for any signs or symptoms of heat distress. 

Heat stress can be a concern for personnel as we teach classes outdoors and as we provide confined space rescue standby services at plants and facilities across the nation. While we are always concerned for our personnel — especially when working around or near confined spaces — we also want to keep an eye on our clients’ personnel as well. Heat distress can occur before you know it — and confined spaces can bring it to the next level.

As most of us know, heat stress is a serious occupational hazard with severe health consequences if not properly managed. It occurs when the body's ability to regulate its internal temperature is overwhelmed by external heat sources, leading to heat-related illnesses. Understanding the stages of exposure, proactive strategies, reactive procedures, and some unique operational considerations can help mitigate the risks associated with heat stress and make your workplace safer as a result.

What are the stages of heat exposure?

First comes heat cramps. Heat cramps are the mildest form of heat-related illness and are characterized by painful muscle cramps and spasms. They typically occur due to electrolyte imbalances subsequent to excessive sweating. If not addressed promptly, heat cramps can progress to more severe conditions. Next in the downward spiral is heat exhaustion. 

Heat exhaustion is a more serious condition resulting from prolonged exposure to high temperatures and inadequate fluid intake. Symptoms include heavy sweating, weakness, dizziness, nausea, headache, and an elevated heart rate. If left untreated, heat exhaustion can progress to heat stroke. 

Heat stroke is the final and the most severe phase of this scorching descent. Heat stroke occurs when the body's internal temperature exceeds 103 degrees Fahrenheit. Symptoms include confusion, loss of consciousness, seizures, hot and dry skin, and a high body temperature. A worker that has lost consciousness and stopped sweating due to heat exposure is in dire need of immediate first aid and professional emergency care.

What are some preventive strategies I can deploy?

To prevent heat-related illnesses in the workplace, proactive strategies should be employed. Consider moving work to a cooler area. If a worker performs a task in direct sunlight, try taking it to a shaded and ventilated area. Alternatively, a cooler environment could be created around the work area using reflectors, tents, etc. It’s also prudent to enforce strict work-rest ratios, specifically during the hottest parts of the day. The hotter the work environment, the more frequent the breaks should become.

For some especially strenuous or lengthy routine tasks, try scheduling work at a cooler time of the year. During work and especially during breaks, supply cold water and electrolyte-replenishing beverages. If your crew is going to be in the heat, then proper hydration and restoration of vital electrolytes like sodium and potassium is a great game plan to fight the good fight. And, don’t just provide the beverages, be sure to encourage and closely monitor workers' intake. 

It’s also very important to educate workers on the signs and symptoms of the three stages of heat illnesses and what to do if they notice things going wrong. Mandating first aid training for employees, managers and supervisors is an excellent method to mitigate the progression of heat exposure. 

Finally, examine the feasibility of “cool-down” areas. These are spaces specifically designed for workers to rest and decrease their body temperature either on a break or when they start to feel symptoms. Equip these areas with shade, ventilation, ice, and first aid supplies for heat-related illnesses. Keep a close eye on workers visiting these areas, especially those who appear distressed.

Next, we’ll take a look at an example utilizing the hierarchy of controls. We suggest that employers take the lead in protecting their workforce from the dangers of overheating. 

Applying the hierarchy of controls

Let's consider a construction site where workers are exposed to high temperatures while performing manual labor tasks. To combat heat complications using the hierarchy of controls, several measures can be implemented:

Elimination: Evaluate if the task can be eliminated or substituted with a less physically demanding activity during periods of extreme heat. While this is not always possible, it’s still important to consider even if it’s a remote possibility.

Engineering Controls: Installing temporary shade structures or using reflective barriers to reduce direct exposure to the sun can be a simple and cost-effective measure to reduce heat stress. Alternatively, consider introducing air conditioning or high-volume ventilation to reduce heat in the work area. Using mechanical aids or equipment to minimize strenuous physical exertion can also decrease the impact on workers in high heat situations. 

Administrative Controls: Adjust work schedules to avoid peak heat hours. Initiate a system of “work-rest” ratios, ensuring that workers have adequate breaks in cool down areas and access to hydration.

Personal Protective Equipment: Provide workers with lightweight and breathable clothing that offers protection without compromising heat dissipation. Encourage the use of sunscreen and wide-brimmed hats. Commercially available cooling vests are also a viable option. 

On-scene medical assistance

In the event of heat-related illnesses, prompt first aid and medical attention are crucial. 

Move workers suffering from heat cramps to a cool area, provide fluids for rehydration preferably a sports drink with electrolytes, and gently stretch and massage the cramped muscles. Note: These workers do not need the aggressive cooling measures that are necessary for more severe phases.

To battle heat exhaustion, in addition to the strategies for heat cramps, use cool compresses, loosen the patient's clothing and use mist fans to help bring the patient’s body temperature down. 

For heat stroke, activate the emergency response system immediately. Administer first aid and alert EMS. Heat stroke necessitates the highest level of cooling aggression. Be quick to move the patient to a cool place and remove excess clothing. Use mist fans, cold compresses, and tepid water on the skin to rapidly cool the worker. Consider using cold water immersion to lower internal body temperature rapidly. Warning: Seek additional training and education before integrating cold water immersion into an on-site first aid program. Do not attempt to give the patient fluids by mouth unless they are awake and alert. 

Warning about confined spaces

Working in confined spaces poses additional risks when it comes to heat stress. The concentration of hazards in such environments can exacerbate heat-related illnesses. Confined spaces are notorious for poor ventilation which may lead to internal temperatures that are far higher than ambient temperatures outside of the space. Introducing ventilation can minimize heat buildup and improve air circulation within confined spaces. The placement of ducted air conditioning can be another solution to this problem. Alternatively, consider relocating the work to an area outside the confined space. Again, this may not always be possible.

In conclusion, heat stress in the workplace is a significant occupational hazard that requires proactive measures and careful management. By implementing preventive measures, such as scheduling work during cooler hours, encouraging and monitoring frequent hydration, and educating workers, employers can significantly reduce the risk of heat-related illnesses. In the event of heat-related symptoms, a swift response is critical, and for severe cases like heat stroke, activate an emergency response and alert EMS immediately. 

References 

• Belval, L. N., Casa, D. J., Adams, W. M., Chiampas, G. T., Holschen, J. C., Hosokawa, Y., Jardine, J., Kane, S. F., Labotz, M., Lemieux, R. S., McClaine, K. B., Nye, N. S., O’Connor, F. G., Prine, B., Raukar, N. P., Smith, M. S., & Stearns, R. L. (2018). Consensus Statement- Prehospital Care of Exertional Heat Stroke. In Prehospital Emergency Care (Vol. 22, Issue 3, pp. 392–397).
• Casa, D. J., Kenny, G. P., & Taylor, N. A. S. (2010). Immersion Treatment for Exertional Hyperthermia. In Medicine & Science in Sports & Exercise (Vol. 42, Issue 7, pp. 1246–1252). Ovid Technologies.
• Casa, D. J., McDermott, B. P., Lee, E. C., Yeargin, S. W., Armstrong, L. E., & Maresh, C. M. (2007). Cold Water Immersion. In Exercise and Sport Sciences Reviews (Vol. 35, Issue 3, pp. 141–149). Ovid Technologies.
• Centers for Disease Control and Prevention. (2020). Heat stress. Centers for Disease Control and Prevention. https://www.cdc.gov/niosh/topics/heatstress/Occupational Safety and Health Administration. (n.d.). Heat. United States Department of Labor. https://www.osha.gov/heat-exposure/hazards