fb tracking

Mapping 5 Months of Deadly Heat

Workers faced extreme heat in counties from coast to coast

By Juley Fulcher

It’s official. We just experienced the hottest September on record, clocking in with an average temperature hotter than the average July[i] from 2001-2010. This was a continuation of the months’ long streak of extreme heat in the summer of 2023.[ii] And the heat isn’t over. So far in October, 16 states[iii] have registered temperatures of 95ºF or higher!

Summer is no longer limited to the traditional 3 months of June, July and August. As heat waves have become longer and hotter, they’ve also expanded to May and September, a trend that will only grow worse as our climate continues to heat up.

Extreme Heat Alerts

In the summer of 2023, millions of workers woke up day after day to warnings from their televisions and smart phones that an excessive heat alert had been issued in their county.

“If you don’t take precautions, you may become seriously ill or even die.”

That’s the advice the National Weather Service (NWS) gives to individuals facing a heat alert in their local area. It’s the advice given to ninety-five percent of the U.S. population this summer, the percent of the population that faced heat alerts raising the alarm of exceedingly dangerous temperatures in their area.

The National Weather Service (NWS) Forecast Office works in concert with local partners daily to issue local area heat alerts[iv] warning residents of the intense heat and cautioning them to take action to protect themselves. The alerts are generally issued when the heat index is expected to reach 100ºF, with some variability based on local temperature norms.  A hundred million people in the United States faced more than a month of dire heat alerts issued from May 1, 2023 through October 2, 2023.[v] Day after day, tens of millions of Americans from coast to coast were confronted with heat alert warnings. There were counties under extreme heat alerts for at least a week in every state in the continental U.S. — counties with a combined 275 million residents. Below is an interactive map of the country showing the number of alerts issued in each county and the average for each state.

Extreme Heat Alerts Issued May 1, 2023 – October 2, 2023

Heat alert data was compiled by the Union of Concerned Scientists.

For each extreme heat alert the public was told that the temperatures in their area would be so hot that they could suffer heat illness or death with even a short period of exposure if they didn’t take protective measures. For many, these warnings came so often that the list of protective measures became ingrained like the rote instructions of a flight attendant — “your seat cushion may be used as a flotation device” — or a roller coaster attendant at an amusement park — “Keep your hands and feet inside the car at all times.”

The heat alert warnings played on repeat in our minds — Stay out of the sun. Use air-conditioning to cool down. When you have to be outside, drink plenty of water, wear sunscreen, slow down and reschedule strenuous activities for a cooler time of day. Take frequent breaks and let your body cool down. These are key elements to prevent heat-related illnesses that can range from syncope and heat exhaustion to acute kidney injury, rhabdomyolysis, heat stroke and cardiac arrest.

Millions of people in the U.S. headed off to work with those words ringing in their ears knowing that they had no control over the simple things included in the guidance. Workers don’t have the power to choose critical actions to protect themselves. They must rely on employers to give them access to these basic life-saving measures.

Employers decide when a worker can reduce or eliminate strenuous activities, including when, or if, workers can take breaks. Employers control whether workers have access to cool drinking water and the time to drink it. Employers decide whether to give workers access to shade with simple solutions like erecting open-air tents, tarps or basic structures for respites from the sun. Employers decide whether to alter work schedules to avoid the hottest portions of the day. Employers decide whether to air-condition indoor workspaces or give employees access to air-conditioned break rooms. Employers can even decide whether to equip the workplace with critical supplies, communications systems and personnel trained to respond to a worker facing dangerous overheating.

As confounding as it may seem, the Occupational Safety and Health Administration (OSHA) doesn’t even have a workplace standard to protect workers from excessive heat. While OSHA is currently developing such a heat standard, the process takes an average of seven to eight years.[vi]

Workers need protection now. The extraordinary, unending heat waves that covered broad swaths of the country during the summer of 2023 are expected to return in 2024.[vii] A workplace heat standard must be in place before next summer.

Congress can empower OSHA to issue an interim standard that would protect workers until a final rule can be completed, and it is essential that Congress takes this step. Helmed by Senators Sherrod Brown (OH), Alex Padilla (CA) and Catherine Cortez Masto (NV) and Representatives Judy Chu (CA-28), Raúl Grijalva (AZ-7), Alma Adams (NC-12), and Bobby Scott (VA-3), the Asuncíon Valdivia Heat Illness and Fatality Prevention Act (S.2501/H.R.4897) would require OSHA to put an interim heat rule in place until the final heat rule is issued.

Congress must pass the bill immediately to ensure workers are protected next summer.

Take Action: Click here to send an email to your senators and representative in Congress asking them to support the Asuncíon Valdivia Heat Illness, Injury and Fatality Prevention Act.


[i] Topping the charts: September 2023 was Earth’s warmest September in 174-year record: 2023 shaping up to be warmest year in NOAA’s global climate record, National Oceanic and Atmospheric Administration (NOAA) (Oct. 13, 2023), https://bit.ly/45D0C3w.

[ii] NASA Announces Summer 2023 Hottest on Record, National Air and Space Administration (NASA) (Sep. 13, 2023), https://go.nasa.gov/401pRLC.

[iii] Data Tools: Daily Weather Records, National Centers for Environmental Information, NOAA, accessed Oct. 17, 2023,https://bit.ly/48YtYw0.

[iv] Heat Watch vs. Warning, National Weather Service, NOAA, https://bit.ly/3QwFtDX, accessed Oct. 18, 2023.

[v] Heat alert data was compiled by the Union of Concerned Scientists. Population data was tabulated using 2022 county population estimates from the United States Census Bureau. https://bit.ly/3tJwZ3m.

[vi] Workplace Safety and Health: Multiple Challenges Lengthen OSHA’s Standard Setting, Government Accountability Office, (Apr. 2012), https://bit.ly/3N8oHG3.

[vii] Michael Sainato, Oliver Milman and Nina Lakhani, Has the U.S. learned to cope with extreme heat? Next summer could be even hotter, The Guardian (Sep. 4, 2023), https://bit.ly/3rTDS1p.