Preventing Heat-Related Illness in Outdoor Workers

When you work outside, fresh air and sunshine give you a sense of freedom you don’t get while toiling in a crowded building. Unfortunately, outdoor environments aren’t always pleasant.

If the heat index rises while you’re hard at work, it puts you at risk of developing heat-related illnesses. Heat exposure becomes an unavoidable fact of life when you work in outdoor environments. You can still prevent heat-related injuries. When you recognize the risks and take the proper precautions, excessive heat doesn’t have to jeopardize your life.

If you or a loved one has been hurt on the job and would like to speak to one of our experienced workers’ compensation attorneys for help.

How Do Heat-Related Illnesses Occur?

Elevated temperatures usually cause discomfort, even if you’re simply sitting outside, performing home maintenance, or walking along a city street. An outdoor environment becomes a life-threatening hazard when you work in extreme heat.

Circumstances that may risk heat-related illnesses include:

  • Executing tasks that are physically demanding
  • Working in high temperatures and humidity
  • Working in direct sunlight
  • Wearing clothing or protective gear that prevents your body from eliminating heat
  • Having personal risk factors that lessen your ability to handle high heat
  • Not adequately adjusting to working in high temperatures (acclimatization)

Occupational heat exposure occurs on the job when your body can’t balance its heat gain with its heat elimination. Typically, heat elimination occurs through evaporative cooling. That’s when perspiration evaporates from your skin through a process that transforms it into a gaseous state. This process doesn’t properly function when you wear restrictive clothing, stay in high-temperature environments too long, and don’t take regular breaks for cooling down.

How Often Does Occupational Heat Exposure Occur?

The Occupational Safety and Health Administration estimates that thousands of workers become sick each year due to heat-related illnesses. While many people don’t require medical treatment or hospitalization, others sustain life-threatening or fatal conditions.

The Bureau of Labor Statistics publishes national data about heat-related workplace fatalities, reporting:

  • Forty-three workers died from heat-related illnesses during a recent year.
  • During the most recently documented ten-year period, 344 workers died from heat-related injuries.
  • Fifty-seven of these deaths involved workers aged 55 to 64.
  • Of the fatally injured workers, 144 worked in construction, repair, or cleaning occupations.
  • Fifty-four workers died while performing materials handling jobs.

Who Is Most at Risk for a Heat-Related Illness?

Every worker risks getting heat-related illnesses when their job requires they work in a hot environment. OSHA research determined that nearly half of all heat-related fatalities occur on an employee’s first day on the job. Seventy percent of heat-related fatalities occur during an employee’s first week.

Occupational heat exposure frequently occurs in certain outdoor occupations.

  • Farmers and agricultural workers
  • Landscapers
  • Construction workers, particularly road and roofing
  • Mail carriers and delivery service workers
  • Firefighters
  • Oil and gas industry workers

Certain health and lifestyle factors increase a worker’s heat risk. These include age, lifestyle, physical shape, obesity, certain prescription medications, and pre-existing health conditions.

Common Heat-Related Illnesses

As the name indicates, heat exposes workers to a range of conditions. The most common include heat stroke, exhaustion, Rhabdomyolysis, heat syncope, heat cramps, and heat rash.

The Centers for Disease Control and Prevention and the National Institute for Occupational and Health discuss these conditions on their Heat Stress—Heat-Related Illness page.

Heat Stroke

Heat stroke is one of the most severe heat-related illnesses, as it triggers a series of dangerous physical changes. A worker develops this condition when their body can’t control its temperature and can’t cool down. The bodily system that automatically generates sweat stops functioning properly. Their temperature rises rapidly to 106 degrees or more. If the affected worker doesn’t receive timely emergency treatment, heat stroke sometimes causes permanent disability or death.

Heat stroke symptoms often include:

  • Confusion,
  • Mental changes
  • Slurred speech
  • Coma or loss of consciousness
  • Hot, dry skin
  • Excessive sweating
  • Seizures
  • High body temperature

Heat Exhaustion

Workers sometimes develop heat exhaustion when their body sweats excessively and they lose too much water and salt. Heat exhaustion mainly affects workers with high blood pressure, elderly workers, and workers in high-temperature environments.

Symptoms often include:

  • Nausea
  • Headaches
  • Weakness
  • Dizziness
  • Excessive Thirst
  • Excessive sweating
  • High body temperature
  • Low urine production


When a worker sustains protracted physical exertion in an excessively hot environment, they sometimes develop Rhabdomyolysis. This condition also known as Rhabdo causes muscle decomposition, rupture, and tissue death. When dead tissues excrete electrolytes and proteins into the bloodstream, they sometimes cause an irregular heartbeat, seizures, and kidney damage.

Symptoms include:

  • Muscle cramps
  • Muscle pain
  • Dark brown urine
  • Physical weakness
  • Exercise intolerance
  • No symptoms

Heat Syncope

Syncope is fainting, lightheadedness, or dizziness. It often occurs after standing too long or arising after sitting or lying down. Dehydration and inadequate acclimatization often cause this condition.

Heat Cramps

Employees who sweat profusely while working often develop muscle cramps or pain. Heat cramps usually affect workers with physically demanding jobs. Their bodies respond by sweating and releasing salt and moisture. Muscle cramps also occur when a worker develops heat exhaustion.

Heat Rash

Heat rash isn’t as serious as other heat-related conditions, but it’s still irritating and uncomfortable. Some workers develop heat rash due to heavy sweating in hot, humid weather. They develop groups of red pimples or blisters on their neck and chest, in their groin, under their breasts, and in other body creases and folds.

Preventing Heat-Related Illnesses

Common Heat-Related Illnesses

When a company runs outdoor operations, it can’t change the oppressive heat, but it must promote safety. Providing a safe working environment is more than a recommendation. Under the Occupational Safety and Health Act of 1970, Section 5[a][1], it’s an employer’s legal duty.

The Act requires that employers provide a workplace “free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.”

To remain compliant, employers must learn about heat-related illnesses and take the appropriate steps to prevent, identify, and treat them. When a worker reports a hazard or a preventable work-related injury occurs, OSHA sometimes assesses financial penalties against non-compliant employers.

The CDC and NIOSH regularly provide information such as the document, Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments, and the health hazard report, Evaluation of Heat Stress, Heat Strain, and Rhabdomyolysis In Park Employees. These and other agency resources offer multiple recommendations to help employers meet their safety obligations.

Establish a Heat Stress Policy

Employers have a legal responsibility to keep their employees safe from heat exposure. They also have the greatest capacity for implementing heat stress elimination strategies. OSHA, NIOSH, and the CDC provide information and resources so you understand what’s important.

Employers should consider these requirements for establishing an effective heat stress policy.

  • Check weather and temperatures daily and understand the terms: excessive heat watch, heat advisory, excessive heat warning, and heat index.
  • Use NIOSH wet bulb globe temperatures to determine outdoor work, workloads, and operation timing.
  • Avoid moderate to heavy outdoor work during months when extreme heat is common.
  • Consider a night work schedule during hours with lower temperatures.
  • Provide cool water throughout the day.
  • Reduce employees’ work hours during extremely hot weather.
  • Require employee self-monitoring.
  • Establish a workgroup: Include employees, a medical advisor, and a safety manager to consider heat policy standards and procedures.

Offer Worker Information and Training

Training is crucial for helping employees minimize heat hazard risks. It’s particularly essential for employees who have never worked in an environment with the potential for heat-related injuries. New employees need focused training to help them understand the risks.

Recommended training topics include.

  • Heat Stress hazard identification
  • Factors that predispose a worker to a heat-related illness
  • Potential health effects
  • Symptoms of heat-related illnesses
  • First aid for heat-related illnesses
  • Precautions and practices for avoidance
  • Effective hydration
  • How caffeine, alcohol, prescription drugs, and non-prescription drugs reduce heat tolerance

Heat Acclimatization

When a company places workers in a hot work environment, they initially show signs of heat exhaustion. After repeated daily exposures, they adapt to the conditions and develop a tolerance for heat. After seven to fourteen days of heat acclimatization, workers display few heat stroke symptoms. Previously acclimatized workers should repeat the process if they experience time away from working in hot environments.

An acclimatization is a form of physiologic adaptation that induces physical changes. When subjected to daily heat exposure for minimum periods, a worker gradually adjusts to working in a heated environment.

Some benefits of heat acclimatization include:

  • Workers sweat more, which increases evaporative cooling.
  • Their sweat contains less salt, which minimizes electrolyte imbalances.
  • The process helps workers maintain a lower body temperature and heart rate.
  • It increases blood flow, allowing greater heat loss through a worker’s skin.

Medical Monitoring

Employers need a monitoring program for employees who regularly encounter heat exposures above CDC/NIOSH’s Recommended Alert Limit (RAL) and Recommended Exposure Limit (REL), as detailed in the above criteria document. RAL measurements apply to non-acclimatized employees. REL limits apply to acclimatized employees. Monitoring programs should include pre-placement, periodic, and emergency medical assessments.

Of note:

  • A doctor or licensed healthcare provider should perform employee evaluations and monitoring procedures.
  • Employees should not pay for monitoring,

Protective Clothing and Equipment

Employers must implement controls and safe work practices that keep employees’ heat exposures at or below recommended levels. The safety agencies recommend protective clothing, air or water-cooled garments, ice-packet vests, etc.

Employee Actions That Prevent Heat Illnesses

Employers have the primary responsibility of keeping their workers safe. Employees must also take responsibility for their safety. CDC/NIOSH provides these recommendations for employees who work in excessively hot environments.

These actions help outdoor workers avoid heat illnesses.

  • Stay Hydrated: Drink water throughout your workday before you feel thirsty. Avoid alcohol and caffeinated beverages that increase urine output.
  • Dress to minimize heat/sun exposure: Wear lightweight, light-colored clothing and a brimmed hat. Wear sunscreen and reapply throughout the day.
  • Avoid prolonged heat exposure: Talk to your employer about scheduling work tasks to avoid extreme temperatures. Take breaks in air-conditioned or shaded areas during and after work.
  • Avoid working alone: Carry a radio to maintain communication in remote areas. Work using a buddy system.
  • Alter adverse eating habits: Eating and digesting a heavy meal increases your body heat. Excessive sugar intake worsens dehydration and sometimes contributes to Rhabdomyolysis.
  • Pace yourself: Don’t overexert yourself while working in a hot environment.
  • Replace salt and minerals: You lose salt and minerals due to heavy sweating. To replace them, consume sports drinks or a physician-recommended alternative.
  • Self-Monitor: If you feel heat-related illness symptoms (racing heart, rapid pulse, dizziness, etc.), take a break in a cool area and notify your supervisor. Seek first aid if necessary. Notify management if a fellow employee displays heat-stress symptoms.
  • Volunteer with a workgroup: Share what you know with fellow employees. Encourage them to hydrate, take breaks, and practice other safety strategies.

Even if you don’t want to volunteer with a workgroup, you can still learn first aid for heat-related illnesses. Through first aid training, you learn how to identify and assist heat-injured workers and help them obtain life-saving medical care.

Contact a Worker’s Compensation AttorneyTop 100 National Trial Lawyers

An employer must take steps to keep their employees safe, but they can’t always prevent heat-related illnesses. If you or a loved one became ill due to heat exposure or any other work-related injury, a worker’s compensation attorney can assess your right to recover compensation. When appropriate, attorneys present your injury claim and deal with insurance company guidelines, procedures, and appeal processes to pursue compensation for your injuries.

When you sustain a work-related injury, you need to understand your rights. Contact a worker’s compensation attorney for a case evaluation, so you know where you stand.