Climate Change Exacerbates Health Risks to Farmworkers

Posted on Wednesday, January 8th, 2020 by Becca Lucas
climate equity

The Union of Concerned Scientists recently released a report entitled “Farmworkers at Risk: the Growing Dangers of Pesticides and Heat” detailing how climate change elevates certain health risks for farmworkers. It focuses on the country’s three states that produce the most labor-intensive crops—California, Washington and Florida—and describes how climate change is causing intensified risks to the workers on whom we depend to produce our fruits, nuts and vegetables.

“While pesticide exposure and heat stress conditions each already represent a threat to farmworkers’ health, climate change promises to compound these threats.”

It is widely understood that climate change is causing more frequent high-temperature days, leading to greater risk of heat stress and heat-related injuries in workers. It is also documented that climate change leads to increased pesticide use due to insect pest, weed and pathogen ranges shifting and expanding, and increased pesticide volatilization (the process of pesticides turning into air vapor) which increases pesticide exposure not only for workers but also agricultural communities. Further, increased heat can increase the toxicity of some classes of pesticides.

“A growing body of research shows that heat stress increases the human body’s susceptibility to pesticides and other toxicants, magnifying the potential for both acute and long-term health effects”

Another connection between heat exposure and pesticides is summed up in the report as follows: “Farmworkers’ high risk of heat stress is related to the nature of their labor: they do hard work under the sun and often through the hottest parts of the year. Direct sunlight can increase the heat index (which combines temperature and humidity to give a “feels like” temperature) by up to 15 ºF. Further, to protect against chemicals (including pesticides), insects, and sun, farmworkers typically wear long sleeves and often wear multiple layers. Such clothing can add up to 12ºF to the “feels like” temperature. Nonbreathable coveralls—used to protect pesticide handlers against the most toxic pesticides—can increase the “feels like” temperature even more, by up to 27º F.”

Where California stands

The average rate of pesticide use on California’s harvested croplands is more than 4.5 times the national average, 8.1 kg per acre compared to 1.7 kg per acre. Nine of the ten pesticides used on the more labor-intensive crops have severe impacts on farmworker health, demonstrated by the average 88 cases per year of acute pesticide poisoning from 2010 to 2015. Rising temperatures compound risks related to pesticide use and application; from 1971 to 2000, there were an average of 102 days annually over 80ºF, the heat risk threshold. In the top 10 agricultural counties, heat risks increase with an average of 115 days annually. These counties, comprising 60% of the state’s harvested acres and 67% of all crop sales, also have higher pesticide use rates than the overall state average.

Figure 2 from page 9 of the report

The report notes that California leads the country in both heat illness prevention and protection for workers and in pesticide regulation—important in a state with as many as 800,000 farmworkers. California is the only state with a comprehensive Heat Illness Prevention Program, mandating water and shade for farmworkers and a work-rest schedule when temperatures exceed 95 degrees. The program also requires that supervisors and employees are trained on prevention, recognition, and treatment of heat illness. That said, more can be done to address the barriers that limit accurate reporting of pesticide and heat-related illnesses.

“Farmworkers at Risk” calls for comprehensive federal policy not only to fight climate change to address severe heat concerns, but also to invest in sustainable agricultural research for on-farm mitigation and adaptation and promote widespread reduction of pesticide use.

Read the full report here.


Quotes from the report: Ferguson, Rafter, Kristina Dahl, and Marcia DeLonge. 2019. Farmworkers at Risk: The Growing Dangers of Pesticides and Heat. Cambridge, MA: Union of Concerned Scientists.

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