Around midday on Wednesday, as the heat index reached more than 102 degrees in Baton Rouge, La., Tremaine Devine was searing burgers on the grill inside his food truck when he began to turn pale and felt lightheaded and short of breath.
“I can’t do this, we have to stop,” Mr. Devine told his fiancée, Kristen Smith, as they were in the midst of serving dozens of people at a corporate event. Ms. Smith cried as customers called for an ambulance. And at the hospital, a doctor told him that he was dehydrated — even after drinking at least eight bottles of water — and had symptoms of heat exhaustion.
“I usually deal with the heat, but today was overwhelming,” he said.
It was the 10th straight day that the temperature had been above 97 degrees, and Louisiana was just one of many states enduring sometimes weeks in or near triple-digit heat.
The effects of climate change have become even more apparent this summer, with temperatures rising to the highest levels in recorded history. Restaurant kitchens, already a sweltering place to work as cooks crank out meals using ovens and stoves, are getting even hotter as temperatures outside climb.
Workers are struggling to cope, and owners are facing new costs as they add air-conditioning units and ventilators in their kitchens. Some say their electricity bills have doubled as the units run all day and night to keep their establishments cool. Restaurant staff are also keeping a careful eye out for symptoms of heat-related illnesses and incorporating more breaks to drink water and cool off.
In Baton Rouge, Mr. Devine and Ms. Smith run Tre’s Street Kitchen, but with the persistent high temperatures the past few weeks, they’ve noticed that customers don’t want to venture outside to eat at their food truck. After Mr. Devine’s health scare on Wednesday, the couple decided that they needed to adapt.
“It’s time for us to get a brick-and-mortar faster than we thought,” Ms. Smith said, adding that they lost more than $2,000 in revenue because they had to end the catered event early. “To survive, we have to shift our business model.”
At Smokey Joe’s BBQ in Dallas, Kris Manning, the owner, said that even with window air-conditioning units running, temperatures inside the pit room have reached 130 degrees as the heat index averaged 106 degrees there this week.
Two of his smokers open toward each other, creating what he calls a “heat alley,” in the middle of the room. To mitigate the impact on his staff, he has them rotating in shifts of 10 to 15 minutes in the pit room. Before they enter, he said, he strongly encourages them to hydrate. He’s also freezing hand towels and hats for people to wear as they check on the brisket and racks of ribs.
“I grew up around heat my whole life,” he said, explaining that he got lightheaded at an outdoor event recently. “But I realized this is not something to play with.”
In Phoenix, the kitchen staff at El Chullo Peruvian Restaurant and Bar have moved up their prep shifts to 6 a.m. instead of their normal 9 a.m. start times so that they can work in a cooler kitchen environment, Esperanza Luzcando, an owner, said in Spanish. The afternoon cooks are taking 10- to 15-minute breaks from the stove every two hours.
About two weeks ago, they had to close the restaurant for two days as temperatures in the kitchen reached 124 degrees. On top of the central air-conditioning system they already had, they have installed two portable units. Now, they’re paying about $1,200 a month for electricity, about 50 percent more than before the heat wave.
“At first, I thought the air-conditioner wasn’t working, but it was the heat outside and the kitchen that caused this,” Ms. Luzcando said in Spanish. “I’ve lived here 12 years, and this is the first time I’ve felt temperatures this hot.”
In the long term, restaurants can redesign their dining rooms and kitchens into cooler working spaces by adding more shade, ventilation and air-conditioning systems, said David Pogue, the author of “How to Prepare for Climate Change: A Practical Guide to Surviving the Chaos” and a former New York Times tech columnist.
In the short term, restaurants can use more fans to make people feel cooler, he said, but that doesn’t necessarily prevent heat illness since actual temperatures are not decreasing around you. And in urban centers like New York City, earlier start times and later night shifts may not improve kitchen temperatures much because pavement absorbs and traps heat during the day and will keep the area hot at night, unlike in the suburbs, where there is more greenery.
“We really need to start treating heat waves like other climate disasters,” said Mr. Pogue, who is also a correspondent for “CBS News Sunday Morning.”
There are no federal or state standards that protect workers from heat stress. But last week, President Biden announced that the Labor Department would issue a heat-hazard alert, which reminded employers to give workers access to water, rest and shade.
The Restaurant Opportunities Centers United, a group that represents workers, has been pushing for such regulations with the Occupational Safety and Health Administration since the organization’s inception in 2002. Those efforts have ramped up in the past three years as temperatures have risen.
“This trend will only continue,” Anthony Advincula, a spokesman for the organization, said of the rising temperatures. “So many restaurant employers are inadequately prepared to mitigate the impact and have shown a disregard for keeping their workers safe and healthy. This is the right time to push O.S.H.A. to enact this heat standard.”
On Tuesday, Cullen Page, a line cook at a pizzeria in Austin, Texas, began treating his back for a heat rash. This summer, he said the temperatures in the kitchen have reached between 90 and 110 degrees. His back faces the restaurant’s four large pizza ovens, which he said are set to 500 degrees.
“Kitchen work is as hard as it is,” he said, “and on top of that, working in this extreme heat just makes it so much worse.”
