The quest to protect farmworkers from extreme heat

On July 21, 2024, temperatures soared in many parts of the world, breaking the record for the hottest day ever recorded on the planet.

The following day—July 22—the record was broken again.

But even as the heat index rises each summer, the people working outdoors to pick fruits, vegetables, and flowers for American tables keep laboring in the sun.

The consequences can be severe, leading to illnesses such as heat exhaustion or heatstroke. Body temperature can rise so high that farmworkers are “essentially … working with fevers,” says Roxana Chicas, an assistant professor at Emory University’s School of Nursing. In one study by Chicas’s research team, most farmworkers tested were chronically dehydrated, even when they drank fluids throughout the day. And many showed signs of developing acute kidney injury after just one workday.

Chicas is part of an Emory research program that has been investigating farmworker health since 2009. Emphasizing collaboration between researchers and community members, the team has spent years working with farmworkers to collect data on kidney function, the risk of heat illness, and the effectiveness of cooling interventions.

The team is now developing an innovative sensor that tracks multiple vital signs with a goal of anticipating that a worker will develop heat illness and issuing an alert.

If widely adopted and consistently used, it could represent a way to make workers safer on farms even without significant heat protections. Right now, with limited rules on such protections, workers are often responsible for their own safety. “The United States is primarily focused on educating workers on drinking water [and] the symptoms of heat-related illness,” says Chicas, who leads a field team that tested the sensor in Florida last summer.

The sensor project, a collaboration between Emory and engineers at the Georgia Institute of Technology, got its start in 2022, when the team was awarded a $2.46 million, four-year grant from the National Institute of Environmental Health Sciences. The sensor is now able to continuously measure skin temperature, heart rate, and physical activity. A soft device meant to be worn on the user’s chest, it was designed with farmworkers’ input; it’s not uncomfortable to wear for several hours in the heat, it won’t fall off because of sweat, and it doesn’t interfere with the physical movement necessary to do agricultural work.

To translate the sensor data into useful warnings, the team is now working on building a model to predict the risk of heat-related injury.

Chicas understands what drives migrant workers to the United States to labor on farms in the hot sun. When she was a child, her own family immigrated to the US to seek work, settling in Georgia. She remembers listening to stories from farmworker family members and friends about how hot it was in the fields—about how they would leave their shifts with headaches.

But because farmworkers are largely from Latin America (63% were born in Mexico) and nearly half are undocumented, “it’s difficult for [them] to speak up about [their] working conditions,” says Chicas. Workers are usually careful not to draw attention that “may jeopardize their livelihoods.”

They’re more likely to do so if they’re backed up by an organization like the Farmworker Association of Florida, which organizes agricultural workers in the state. FWAF has collaborated with the Emory program for more than a decade, recruiting farmworkers to participate in the studies and help guide them. 

There’s “a lot of trust” between those involved in the program, says Ernesto Ruiz, research coordinator at FWAF. Ruiz, who participated in data collection in Florida this past year, says there was a waiting list to take part in the project because there was so much interest—even though participants had to arrive at the break of dawn before a long day of work.

“We need to be able to document empirically, with uncontroversial evidence, the brutal working conditions that farmworking communities face and the toll it takes on their bodies.”

Ernesto Ruiz, research coordinator, Farmworker Association of Florida

Participants had their vital signs screened in support of the sensor research. They also learned about their blood glucose levels, cholesterol, triglycerides, HDL, and LDL. These readings, Ruiz says, “[don’t] serve any purpose from the standpoint of a predictive variable for heat-related injury.” But community members requested the additional health screenings because farmworkers have little to no access to health care. If health issues are found during the study, FWAF will work to connect workers to health-care providers or free or low-cost clinics.

“Community-based participatory research can’t just be extractive, eliciting data and narratives,” Ruiz says. “It has to give something in return.”

Work on technology to measure heat stress in farmworkers could feed back into policy development. “We need to be able to document empirically, with uncontroversial evidence, the brutal working conditions that farmworking communities face and the toll it takes on their bodies,” Ruiz says.

Though the Biden administration has proposed regulations, there are currently no federal standards in place to protect workers from extreme heat. (Only five states have their own heat standards.) Areas interested in adding protections can face headwinds. In Florida, for example, after Miami-Dade County proposed heat protection standards for outdoor workers, the state passed legislation preventing localities from issuing their own heat rules, pointing to the impact such standards could have on employers.

Meanwhile, temperatures continue to rise. With workers “constantly, chronically” exposed to heat in an environment without protective standards, says Chicas, the sensor could offer its own form of protection. 

Kalena Thomhave is a freelance journalist based in Pittsburgh.