Summer Heat Wave Safety 101: What to Know Before Working in Scorching Conditions

As we approach the start of summer, the Northeast is experiencing its first heat wave. High temperatures are expected to soar beyond 90s and get up to the 100s. As people around the world adjust to this summer’s stifling heat wave and take steps to protect their health, or avoid the heat entirely, folks whose jobs keep them outside (or inside in an overheated room) may be at a higher risk of heat illness, including heatstroke.

In the US, heat is the biggest killer when it comes to environmental effects on health. Someone’s health, mobility or age can influence how they respond to heat, but people who work in construction, agricultural or other jobs outside have always had a higher risk of heat illness — the Bureau of Labor Statistics reports that 436 people have died from heat exposure at work since 2011. 

But the demand for food, construction and more doesn’t stop when extreme heat kicks in. If your job places you at higher risk of heat illness, outdoors or indoors, here’s what to know and tips for staying healthy.

How hot is too hot to work? 

There is no exact number or federal standard for how hot it has to be to be “too hot” to work, though more specific federal guidelines for working in the heat have been in the works for a couple of years. 

Following summer 2023’s announcement by the Biden administration, the Occupational Safety and Health Administration may “intensity its enforcement” of heat safety in industries like construction and agriculture. In the past, OSHA has cited employers “under the general duty clause for heat stress violations,” according to the Venable law firm. 

But states and cities can also make their own rules for worker safety: Check the map for OSHA-approved worker health plans. As the Wall Street Journal reports, states including California, Oregon, Washington, Colorado and Minnesota have rules requiring businesses to provide things like regular breaks and free water access. Texas, according to the WSJ, has a rule taking effect in September that will ban cities like Austin and Dallas from mandating their own regulations for heat within businesses.

In general, whether heat is harmful to the human body, or when heat becomes a hazard at work, depends on a combination of factors in addition to the actual number of degrees Fahrenheit the temperature hits, according to the Occupational Safety and Health Administration. It’s these combinations of factors that contribute to heat, and risk of heat illness or stress, that OSHA requires workplaces to consider when managing worker safety.

These factors can be boiled down to sources of heat-related illness in the workplace: environmental heat (such as the temperature, humidity or whether there’s airflow or wind) and metabolic heat (getting hot because of your workload or the physical labor you’re doing). 

This means the length of time it’s safe for you to be at work on extremely hot days — or whether it’s safe at all — will depend on things like how much you’re doing physically, the clothes or gear you have to wear to do your job and whether you have access to frequent shade and water breaks. Importantly, it also depends on whether you’ve been “acclimatized” to the heat, which the US Centers for Disease Control and Prevention describes as gradually building up a tolerance to working in the heat over a period of a couple weeks. According to OSHA, most outdoor deaths occur during the first few days of someone working in hot weather because their body needs time to build up a tolerance. 

As part of its explanation for how hot “too hot” is, OSHA recommends workplaces take heat stress level into account based on wet bulb globe temperature markers, which takes into account things like temperature, humidity, wind speed and sunlight. Heat index, which is what we typically see when looking at heat advisories, is actually a reading based in the shade, according to the National Weather Service. 

The signs of heat illness and when to get out of the heat 

Heat exhaustion and heatstroke are what we think of when it comes to heat illness. Heat exhaustion typically comes before heatstoke, but not always. Some symptoms of heat exhaustion, per the CDC, include: heavy sweating, nausea, cold and clammy skin, muscle cramps, tiredness or weakness and a fast pulse. If you’re experiencing these signs of heat exhaustion at work, it’s important you working and cool down as soon as possible. Get to the shade or indoors, drink water and loosen your clothes, per the CDC.

Heatstroke is a medical emergency and can lead to death if someone doesn’t get help. While some symptoms of heatstroke overlap with heat exhaustion, like headache and nausea, heatstroke will overheat a person’s body (103 degree temperature or higher) and can cause them to lose consciousness or start acting confused. If you or someone you’re working with may be experiencing heat stroke, call 9-1-1. 

While you wait for medical services to arrive, get the overheated person to shade and cool them down by any means: Put cold towels on their skin, pour cold water on them and loosen or take off parts of their clothing. The CDC doesn’t recommended you give someone with heatstroke anything to drink, since they may be unconscious or unable to swallow, which makes it a choking hazard. If they’re conscious and responsive, however, the Mayo Clinic recommends giving them small sips of water while waiting for emergency services to get there. 

Tips for staying safe when working in hot weather

Even if your workplace doesn’t require breaks or automatically provide framework to reduce the risk of heat illness, there are things you can do to reduce your risk.

Wear the right clothes: Try to wear less clothing or clothing that’s breathable, loose fitting and light-colored (lighter colors absorb less sunlight). Read all about clothes that can help keep you cool.

Stay hydrated: You should be drinking water frequently throughout the day, preferably before you become thirsty, according to a heat illness info sheet for employers from OSHA and the National Institute for Public Safety and Health. Some reusable water bottles can help keep water cool for longer, if your work doesn’t have a nearby water station with cold water. 

A good way to check you’re drinking enough is to monitor the color of your urine: It should be light-colored or nearly clear when you’re adequately hydrated, according to the fact sheet. If you want to get some added hydration through food during your lunch break or snacks (eating may help you stave off things like lightheadedness, too), consider eating these hydrating foods. 

Check your medications and know your individual health risks: Older adults and people with underlying health conditions, including common ones like heart disease and diabetes, can be more susceptible to heat illness. Medications people take to manage health conditions also may make it harder for someone’s body to regulate temperature, so check in with your doctor or pharmacist if you take daily medication but also work in high heat.

Consider your individual workload risk: The more physical activity you’re doing at work, the hotter your body will be, and the higher your risk for heat illness is. The same goes for clothing (more clothing equals higher body heat and higher risk) air flow (less air flow means higher risk), and the list goes on.