The food truck economy has exploded in the past decade. According to U.S. Census Bureau estimates, food trucks were a $1.2 billion industry nationwide in 2017 — the figure is likely even higher today — and 1 in 8 of all food trucks in the U.S. operate in California.

In Los Angeles, the trend has been a boon for consumers, offering not only convenience but also exposure to authentic ethnic cuisine and inventive new flavors. And it has generated vital income for owners and workers — many of whom are immigrants. (Published studies have estimated that 30% of food truck owners and 51% of food truck workers are immigrants.)

But a report by UCLA researchers found that even on a relatively cool day in Los Angeles, the conditions on food trucks could be downright dangerous for workers.

The analysis found that even though it was just 61 degrees Fahrenheit outdoors, temperatures near the trucks’ grills could reach 100 degrees Fahrenheit — up to 35 degrees hotter than the rest of the truck — and stay that way for hours. What’s more, those triple-digit temperatures persisted until 11:30 p.m., well after outdoor temperatures had cooled down.

Food truck workers interviewed for the report said they had experienced nose bleeds, headaches, dizziness, irritability, dehydration, nausea and vomiting while working on the trucks.

The study was conducted by researchers from the UCLA Heat Lab, who took temperature readings from five food trucks serving the Westwood neighborhood of Los Angeles. They placed sensors in three key spots of the trucks: next to grills and ovens, in the food prep areas and by the serving windows. Temperature data was recorded on board five trucks during one April 2022 evening; workers and truck owners were interviewed between February and May 2022.

UCLA Heat Lab

On one food truck analyzed in the report, temperatures at the cooking station exceeded 100 degrees, even on a relatively cool night.

Some of the trucks analyzed in the study had air conditioning units, but AC isn’t always effective, in part because of the trucks’ design and food safety regulations.

“The regulations around food trucks are still a work in progress, and they haven’t balanced food safety with worker safety,” said Bharat Venkat, the director of the lab and an associate professor at the UCLA Institute for Society and Genetics.

For example, public health rules dictate that air conditioning units must be installed so that they don’t harm the food — either from contamination or as a result of temperature changes. As a result, AC units are generally placed away from cooking and prep areas.

“Everybody’s like, ‘Oh, well, you have AC,’” said one food truck operator who spoke with the researchers. “It doesn’t work. [The designer] put the vent windows right next to the AC, so all the air goes straight up.”

Other food safety regulations require that trucks’ back doors be kept closed, to keep insects out. To increase air flow, some truck owners install screens at the back entrance, but owners worry that using screens might break local health codes. “Installing a screen isn’t technically the same as keeping the door closed, and this lack of clarity is a problem,” Venkat said.

And devices like swamp coolers could help alleviate the dangerously dry conditions that can occur, but installing them would require health department approval.

Venkat said the food truck scene in Los Angeles is a powerful example of the “thermal inequality” that persists more broadly in society today. And it may be inadvertently normalizing “racialized assumptions that certain groups can tolerate heat better than others,” he said.

“At a biological level, race does not determine how vulnerable or resilient you are to the harmful effects of extreme heat,” said Venkat, who also holds UCLA appointments in history and anthropology. “But the idea that it does leads to low-income people of color being hired into high-heat jobs where their health and their very lives are put at risk.”

In the report, the researchers recommend that Los Angeles County revise health codes for food trucks, with the goal of ensuring better air flow on the vehicles without compromising food safety.

Venkat said the heat-related dangers identified in the study are similar to those in a range of other professions — construction workers, agricultural hands and mail carriers among them — in which the risks for heat stroke and other health conditions are worsening due to the rising temperatures caused by climate change.

“There are a lot of people in this country who do work in very difficult, extreme-heat conditions so that the rest of us can stay cool, and that’s thermal inequality,” he said. “No one’s thinking, ‘I want other people to suffer so I can buy fresh produce or so I can have packages delivered to my doorstep,’ but it tends toward a zero-sum game.”