As Temperatures Get Hotter, Pesticides Are More Dangerous to Farmworkers

For the nation’s 2.4 million farmworkers, climate change is poised to exacerbate the harms of pesticides, a growing body of research shows.

Heat stresses the body, making it more vulnerable to pesticides and other toxicants, and protective clothing worn in the heat only adds to this stress. Hotter temperatures can also lead to higher evaporation rates, increasing farmworkers’ exposure as more pesticides are applied to crops. And heat can boost rates of chemical transformation of pesticides into more toxic compounds.

“When it’s in the air, you are inhaling it through your nose. You are exposed to it through your other organs like skin. Your skin can absorb some of the pesticides [that are] in the air, and also when you’re sweating as part of doing your work you are increasing the pore size of your skin,” said Omanjana Goswami, a scientist in the food and environmental program at the Union for Concerned Scientists, an advocacy group. “It is awful. There is no other word for it.”

In addition to threatening workers, rising temperatures likely will expand pesticide use, as pests and pathogens enlarge their ranges and more weeds spring up in crops, according to a report by the Union for Concerned Scientists.

Thousands of U.S. farmworkers suffer annually from acute pesticide poisoning, although data is limited, according to the Union for Concerned Scientists report, citing the Environmental Protection Agency. Many cases go unreported, and states also have different reporting practices. 

The problem affects a population that is particularly vulnerable. A majority of U.S. farmworkers were born in other nations and are people of color. Jeannie Economos, pesticide safety and environmental health project coordinator at the Farmworker Association of Florida, characterized farmworkers as “landless farmers.” 

“This is definitely a case of environmental injustice,” she said. “If they had access to capital, to land, to nondiscriminatory regulations and practices, to financial assistance, they might be able to be farmers themselves. But they’re not.

“And if they had legal status and they weren’t being demeaned because of their immigration status, if they weren’t experiencing horrible conditions in their home countries, they might be farmers themselves. But they are relegated to being farmworkers because they are at the behest of government and the system.”

Farmworkers are at risk whether or not they work directly with pesticides, and field workers who do not directly handle the chemicals account for the majority of reported poisonings, the Union for Concerned Scientists said in its report. Many employers do not post adequate warnings about fields that recently were sprayed and fail to provide protective gear or trainings on how to use it, the report said. Other research shows that protective PVC gloves actually can break down as temperatures increase and become less impervious to the chemicals. Family members or other close contacts can be exposed when they encounter residue on farmworkers’ skin and clothing. 

Chronic pesticide exposure is associated with cancer, depression, diabetes, neurodegenerative diseases and reproductive issues, according to the Union for Concerned Scientists report.

“We tell people, don’t pick up your children when you get home until you take your clothes off and take a shower, because you’re going to contaminate your kids,” Economos said.

Heat is the leading weather-related killer in the United States. Every year, thousands of U.S. workers suffer heat-related illnesses and injuries. A total of 1,042 worker deaths related to heat were documented between 1992 and 2022, an average of 34 annually, according to the Occupational Safety and Health Administration (OSHA), citing the Bureau of Labor Statistics.

Excess heat affects the body’s ability to regulate its internal temperature, which can lead to heat cramps, heat exhaustion and heatstroke. Hotter temperatures can also exacerbate nervous system, respiratory, cardiovascular and diabetes-related conditions and even affect children’s ability to learn. For outdoor laborers, symptoms such as fatigue and dizziness especially can be hazardous when the work involves dangerous conditions or equipment. 

There are few federal or state regulatory protections for farmworkers from heat. The Occupational Safety and Health Administration in 2024 proposed a new standard that would more clearly define employer obligations and require employers to evaluate and control heat hazards in their workplaces. Two years later, the proposal is moving forward, but slowly.

In the absence of a specific federal regulation, OSHA has relied on the general duty clause of the Occupational Safety and Health Act of 1970. The clause requires employers to provide a workplace free of “recognized hazards” that can cause “death or serious physical harm.”

California, Colorado, Maryland, Minnesota, Nevada, Oregon and Washington have implemented state-level heat protections. But some states, including Florida and Texas, have prohibited the protections at the local level. In 2024, Florida lawmakers banned local governments from establishing any such protections for outdoor workers. The legislation came after commissioners in Miami-Dade County considered a proposal that would have required construction and agricultural companies to provide water and rest breaks when the heat index hit at least 95 degrees. The proposal also would have required training in heat illness and first aid. 

“Farmwork is dignified, important work,” Economos said. “I’m not trying to get people out of farmwork. We’re trying to elevate farmwork because it is a skilled profession. Unlike what (people say), that it is unskilled work—try it.”