Heat stress is a constant threat on many worksites, including interior jobsites where the sun may not be a concern. Commercial ovens, furnaces, industrial machinery, and even large windows are thermal energy sources which can expose workers to elevated heat stress.

If your worksite contains heat hazards like these, your safety personnel and your employees should be able to recognize heat stress while on the job. Heat illness can be successfully treated if it’s identified early, and that means understanding what heat stress looks like and how it affects workers.

What are the Signs of Heat Stress?

Hundreds of thousands of workers experience some form of heat illness every year. This includes milder issues like heat cramps or heat rash, and serious, potentially life-threatening heat illnesses like heat exhaustion or heat stroke. It’s especially important for workers and safety personnel to respond quickly if someone onsite develops heat exhaustion, which presents with the following symptoms:

• Skin that’s cool and clammy – goosebumps are common even in the sun
• Fatigue
• Faintness and dizziness
• Nausea or feeling sick
• Muscle cramps
• Headache
• Blood pressure dysregulation

These symptoms may develop quickly, or they may emerge slowly. In either case, if the above symptoms of heat illness are present, the affected worker must be removed from any thermal stresses and treated – potentially at a medical facility.

If heat exhaustion isn’t addressed promptly, it may progress to heat stroke, which presents with many of the same symptoms as heat stress, like headache, cramps and nausea. However, since heat stroke is a late-stage version of heat illness, its symptoms are more severe and may include:

• Altered mental state, such as confusion, irritability or delirium
• Loss of consciousness or loss of muscle control
• Rapid, shallow breathing
• Rapid, weak pulse
• Extremely high body temperature (in excess of 104 degrees Fahrenheit)

Heat stroke is a medical emergency that can quickly progress to permanent or fatal complications if not addressed. Specifically, medical experts urge treatment within 30 minutes of developing heat stroke, as this will greatly reduce the risk of developing permanent disabilities.

How to Respond to Heat Stress on the Jobsite

The first step in protecting workers is ensuring everyone knows what heat stress looks like, including safety personnel, supervisors and workers. The second step is having an emergency action plan (EAP) in place to mitigate heat illness when it does appear. Every EAP should be tailored to the jobsite to ensure maximum effectiveness and typically includes the following:

• A review of all identified hazards on the worksite – Every EAP includes a list or diagram of all potential hazards on the jobsite. Some EAPs specify every hazard, such as falls or vehicle traffic, while others are hazard specific. Some employers develop a heat-specific EAP if there are several heat sources or heat traps present. This can improve awareness of those heat hazards and facilitate preventative measures.
• An inventory of all onsite heat safety resources – To treat or prevent heat illness, safety personnel should have some basic resources on hand, like cool wraps or cooling gaiters, electrolyte tablets and access to cool, clean water. Your EAP should detail what resources are available onsite and where those resources are located for rapid response purposes.
• A list of heat safety procedures to mitigate potential heat hazards – Employers mitigate the risk of heat stress by implementing different work rotations, increasing the number or frequency of breaks or through other dynamic safety measures. These should be detailed in the EAP and integrated into your training approach.
• A list of emergency medical procedures to enact in response to heat illness – If a heat-related emergency does occur, your EAP should clearly lay out the appropriate response. This includes emergency treatment protocols such as where to take the affected worker, who to contact, what to do to reduce the worker’s body temperature, and so on. Your supervisors will reference the EAP in an emergency scenario, so be as detailed here as possible.
• Contact information for all relevant parties – In the event of an emergency, there are several parties to contact for treatment and reporting purposes. This includes a nearby medical facility where the affected worker will be taken to for treatment. It also includes contact information for any supervisors or safety personnel responsible for enforcing heat safety measures.

Three Steps Employers Can Take to Reduce Heat Stress on the Jobsite

In addition to developing an EAP, employers can take a few basic steps to ensure their worksite is guarded against heat stress, including:

• Equipping workers with heat monitoring tools – Field workers are typically at the highest risk of heat stress, so many employers focus on them first. And a basic, inexpensive way to do so is by equipping onsite personnel with temperature-taking tools. A popular option is to hand out TWIC cards with a liquid crystal thermometer (LCT) integrated into the card itself.LCT-modified TWIC cards serve dual purposes for employers. For one, it can include the company’s branding or heat safety measures for easy reference. And two, these cards can be used to take a quick and accurate temperature reading – so workers know exactly when it’s time to elevate heat safety protocols.
• Ensuring access to cool water and cooling stations – Regular, adequate hydration is key to staving off heat stress and should be the number one priority for your safety managers. No matter the conditions on the ground, workers need access to cool, potable water. They are also entitled to regular breaks to ensure they have time to hydrate and acclimate to stressful conditions.
• Modifying work patterns when thermal stresses are elevated – There are days where little can be done to blunt the effects of extreme heat. If heat stresses will be elevated throughout the workday, consider modifying work rotations to either prioritize less strenuous, less hazardous work – or rotate workers quickly through stations to ensure no one person is exposed to excessive heat stress. In extreme circumstances, it may be necessary to schedule work at night and prevent thermal stresses due to sun exposure.

In short, supervisors and safety personnel must be adaptable when dealing with heat hazards. Heat is invisible, odorless and seemingly harmless, right up to the point where worker health is potentially affected. It’s important to be proactive when heat is a threat and ensure there are procedures in place when workers are stressed from the heat.

Give Your Workers a Chance Against Heat Stress with the Right Training and Tools

Heat stress is one of the most common hazards for workers on the jobsite. It’s also easy to forget about, as heat is a silent, invisible threat. However, there are proven measures that every employer can take to ensure their worksite is protected from heat stress. This includes equipping your workers and safety personnel with the right tools and resources and ensuring there’s an EAP in place that your employees are trained on. This will maximize emergency preparedness for everyone onsite – which can literally be the difference between life and death.