Taylor Swift’s show at an open-air stadium in Rio de Janeiro this past Friday was supposed to be a raucous kickoff to the pop star’s first concert tour in Brazil. Instead, fans across the world were left reeling after a concertgoer died from extreme heat minutes into Swift’s Eras Tour performance.

Ana Clara Benevides Machado, 23, traveled 880 miles and waited in line outside for more than eight hours, along with tens of thousands of other fans, to see her favorite artist. That day, the heat index, or “feels-like” temperature accounting for humidity, soared to an all-time high of 138 degrees Fahrenheit in Rio. Brazil was sweltering through its eighth heat wave of the year — and it’s only spring. More than 1,000 people fainted from heat exhaustion inside the venue; others were vomiting. 

Benevides lost consciousness just minutes into the set, during the song “Cruel Summer,” and later died of cardiac arrest at a nearby hospital. 

Researchers have documented how hot weather vastly increases the risk of heart failure and other cardiovascular issues. Concertgoers say Time for Fun, the Brazil-based entertainment company running the event, refused to let people bring in water despite the heat and blocked air vents in the venue to prevent people outside from listening in. Swift postponed her second show in Rio, originally scheduled for Saturday, to Monday night, citing safety concerns due to the ongoing high temperatures. She also put out a statement on Instagram saying she was “devastated” by Benevides’ death. “This is the last thing I ever thought would happen when we decided to bring this tour to Brazil,” Swift wrote. (Time for Fun did not immediately respond to a request for comment.) 

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The Swift concert disaster comes on the heels of a summer where fans experienced heat illness at a Beyoncé concert in Maryland and at an Ed Sheeran concert in Pittsburgh. These incidents serve as a stark reminder of the dangers of extreme heat, which will only grow worse as heat waves intensify as a result of climate change. But they also demonstrate that event mismanagement and a lack of heat preparedness can be deadly. Most heat-related deaths and illnesses, including at concerts and other large events, are preventable, climate health and heat safety experts told Grist. To avoid future injuries, concert organizers should take steps to proactively plan for heat, communicate health advisories and safety measures in advance, provide water and onsite medical care, and ensure proper airflow and ventilation.

Fans wait in line outside the Nilton Santos Olympic stadium for Taylor Swift’s Eras Tour concert during a heat wave in Rio de Janeiro on Saturday. The show’s postponement was announced hours before the star was scheduled to appear. Silvia Izquierdo / AP Photo

“People go to these events to have fun. You never go to one of these thinking something horrible is going to happen,” Kevin Kloesel, a professor of atmospheric sciences at the University of Oklahoma, told Grist. “So it’s incumbent upon the event organizers to make sure that it is the safest environment possible.”

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Kloesel, who oversees weather forecasting and safety for around 400 annual outdoor events at the University of Oklahoma, said that when it comes to extreme heat, event organizers need to provide three key things: shade, hydration, and air movement. For example, setting up canopies to shade the endless lines concertgoers stood in for hours in Rio would have been one easy way to cool people down. Having enough water on hand, and providing it to attendees for free, is also crucial. Organizers should also find ways to ventilate the event space, including, potentially, by reducing seat capacity. 

Morgan Zabow, a community heat and health information coordinator at the National Oceanic and Atmospheric Administration’s Climate Program Office, specified that indoor venues should provide air conditioning and not rely solely on electric fans, which can make stifling conditions worse by blowing hot air at a faster rate.  

Event organizers should also send out health advisories via text message or email well in advance, Zabow said. Those messages could include heat forecasts and tips to stay cool, like regularly drinking water and avoiding sugary beverages, caffeine, and alcohol, which can inhibit the body’s ability to cool off. Wearing loose, light-colored clothing is another preventative measure advisories could recommend. 

But even with these precautions, heat can still take a toll, especially for people who are older or have pre-existing medical conditions, or those from cooler climates who aren’t used to hot weather. That’s why having easily accessible medical staff onsite is so important, Kloesel said. At football games, Kloesel and University of Oklahoma staff arrange cooling tents with medical personnel around the field in case attendees fall ill.

There are also ways to avoid the heat altogether. In Arizona, it’s become increasingly common to delay sports practices and other events until later in the evening when it cools off, said Ladd Keith, a heat policy expert and professor of urban planning at the University of Arizona. Kloesel noted that if concerts created more reserved seating, people wouldn’t have to line up outside for hours to secure a spot. Canceling or postponing events, as Swift did for her second concert in Rio, is another option. Organizers can also consider shifting summer events to a cooler season like fall or winter. All these steps, experts stress, require careful and intentional planning far in advance. 

Individuals can take steps to stay safe, too. Keith noted that heat can affect anyone, including young people and those in good health — as the Taylor Swift concert demonstrated. Zabow suggested using a buddy system in which friends monitor one another for symptoms of heat exhaustion, including heavy sweating, dizziness, and nausea, and leave early to get help if needed. “I know it’s hard to leave a stadium early and miss things, but your life is so much more important,” she said.

At Swift’s concert on Friday, however, attendees said Time for Fun had blocked exits, making it difficult to leave. The company announced new measures to provide water and emergency responders Saturday morning. Meanwhile, Brazil’s consumer protection agency has announced that the federal government plans to investigate Time for Fun

“It is heartbreaking that preventable things happened,” Kloesel said. “You have to know your venue, you have to know your fans, and you have to have a way of taking care of them and mitigating that risk as much as you possibly can, rather than just leaving it to chance.”