For employees who spend all day working in the heat and surrounded by asphalt, the summer weather can pose a serious threat to their health and safety. Year after year, road crews and construction workers battle the heat, but many fail to recognize it as a common occupational safety hazard.

In 2014 alone, heat stroke and other heat-related illnesses (HRIs) killed 18 workers and caused thousands of others to suffer the effects of heat stress. The dismal reality is that heat-related illness and death is preventable when appropriate prevention methods are used.

Hot summer days can reach temperatures of up to 120°F in Texas. Combine searing temperatures with asphalt mix nearing 300°F and there’s no question that you've got a safety issue that demands attention. Construction site safety should include prevention of HRIs during these hot weather months.

The “Heat Island” Effect

Many workers can attest that urban areas are more susceptible to heat changes than rural ones. Impermeable surfaces like buildings, roads, and other infrastructure can trap heat, causing it to be warmer than the permeable areas of open land and vegetation. The Environmental Protection Agency (EPA) defines "heat islands" as the formation of "islands" of higher temperatures on surfaces and atmospheres in urban areas than what is typically found in rural areas.

On a hot summer day, surface temperatures of roofs and pavement can increase to as much as 50 – 90°F hotter than regular air temperatures. In contrast, atmospheric urban heat islands are usually weaker during the late morning and daytime hours, but increase after sunset as urban infrastructure slowly releases heat. On average, studies have found that an urban environment with one million people can be 1.8 – 5.4°F warmer than its surroundings.

This certainly isn’t music to the ears of urban construction workers, who often spend their days surrounded by scorching concrete and pavement.

Who Is Most at Risk While Working in the Heat?

It makes sense that while the sun and heat can pose a threat to any outdoor worker, particular attention needs to be focused on those working with asphalt.

Why? I'm glad you asked:

  • Pavement covers more than 45 percent of urban areas, so there’s a good chance that any construction worker in a medium to large city will experience hotter than average temperatures
  • These surfaces get as hot as 140°F on summer days—that’s hot enough to cook an egg!
  • The dark color of asphalt readily absorbs heat from the sun, releasing it back into the air and increasing the temperature of surrounding areas

So, while landscapers may be vulnerable to sunburns, dehydration, and heat stroke, they are generally working in and around permeable surfaces like grass and garden beds. These surfaces absorb heat from the sun and release it slowly during the evening, helping to moderate the surrounding temperature.

Asphalt workers, on the other hand, spend their days around non-permeable surfaces that readily absorb heat and increase the surface temperature drastically, causing an already sweltering day to feel even hotter. These workers are even more susceptible to heat-related illnesses due to the surfaces commonly present in their work environment.

Recognize the Signs of Heat-Related Illness

Being able to recognize the signs of heat stress before an illness takes hold is crucial to protecting construction workers. There are a variety of heat-related illnesses that can arise, including heat stroke, heat exhaustion, heat syncope (fainting), heat cramps, and heat rash.

Look for these tell-tale signs:

  • Hot, dry skin or profuse sweating
  • Elevated body temperature
  • Headache
  • Nausea
  • Dizziness or light-headedness

First aid recommendations depend on the individual and their symptoms, but every worksite should have appropriate safety equipment that is easily accessible. Heat-related emergencies are often overlooked and can be deadly, so be sure to obtain medical help when necessary.

Top Tips to Protect Workers from Extreme Heat

We’ve established that the risks are there. Thankfully, there are a variety of ways to help protect employees from heat-related illness.

  • Wear long sleeves. It might seem counterintuitive, but wearing long sleeves allows you to take advantage of your body’s natural cooling system—sweat. Lightweight fabrics in light colors are best since they absorb less heat than darker materials
  • Don’t forget a hat. Not only do they protect your head from getting sunburned, they can also help create a bit of personal shade. Consider providing outdoor employees with large-brimmed hats
  • Hydrate well and often. Drink about 5 to 7 ounces of water every 15 minutes, even if you aren’t thirsty. Electrolytes can also help replenish the minerals that you sweat out. Great sources of hydration include coconut water, lemon water, fruits and vegetables, nut butters, and salty foods
  • Make healthy food choices. A healthy, balanced meal will provide the energy needed to get through a tough day. Need a snack? Grab a potassium-rich banana, which your body can use to help replenish itself and prevent dehydration
  • Take frequent breaks. Provide a cool, shady spot for workers to take breaks. If possible, have portable fans available to circulate cooler air
  • Adjust scheduling. Start work early to take advantage of the cooler times of the day. The hottest time of day typically exists during the early afternoon (1 to 3 pm), so try to plan the bulk of the work in the early morning hours or late evening

OSHA’s heat safety tool is a great app to help ensure worker safety on hot summer days. It takes the heat index (a combination of the temperature and humidity) into account to determine a risk rating. From there, the app provides users with precautions that they can take to mitigate their risk of heat stroke, heat exhaustion, and other HRIs. It also offers signs and symptoms to watch out for and provides guidance for both supervisors and workers.

It’s Not Just Good Practice—It’s the Law

While some workplace safety hazards can be eliminated, the hot summer weather is not one of them. Extreme heat is to be expected during the summer months and employees will always be vulnerable to heat-related illnesses.

Under OSHA regulation, employers are responsible for providing workplaces that are free of known safety hazards—this includes protecting workers from the dangers of extreme heat. Having a complete heat illness prevention program in place is one of the best ways to mitigate the risks.

If you’re an employer or safety manager with employees working on asphalt, make sure you and your workers know the symptoms of heat stress, how to prevent heat-related illnesses, and what to do in case of an emergency. By providing the right safety equipment, education, and training, you can rest easy knowing that your workers are safe in those dog days of summer.