On May 5, 2017, over 50 farmworkers were exposed to a previously banned pesticide, chlorpyrifos, while working in a cabbage field just south of Bakersfield, California. According to Efron Zavalza, supervisor and food safety specialist for Dan Andrews Farms, a chemical odor traveled from a nearby mandarin farm, which had been sprayed with the organophosphate, also known as Vulcan.
Chlorpyrifos causes symptoms such as tearing, runny noses, nausea and dizziness. Under the Obama administration, organophosphates were scheduled to be to be taken off the market by the EPA. In March of 2017 the current EPA chief, Scott Pruitt, announced that he would not follow the recommendation of the agency’s own scientists and instead allowed chlorpyrifos continued use, one of his first formal actions.
Outside Bakersfield, multiple agencies responded to the scene of the chlorpyrifos exposure last spring. Workers were rinsed-down and “decontaminated.” But half of the agricultural workers had already left the area before emergency crews arrived, according to local news reports. Of those workers who were examined, 12 people reported symptoms of nausea and vomiting, one fainted, and at least one worker was transported to the hospital. The Kern County Department of Public Health said at the time they believe chlorpyrifos caused the symptoms.
Chlorpyrifos had been used to control insects in homes and fields for decades but has been banned for residential use for more than 15 years. When inhaled, the chemical is known to cause the symptoms described above, but in higher doses, those exposed suffer from a more severe poisoning syndrome, with symptoms including tremors, weakness and muscle twitching, vomiting, diarrhea and vision problems. Researchers at Columbia University have previously associated exposure to chlorpyrifos with small but measurable differences in brain function in studies of children born to pregnant mothers in low-income neighborhoods with household exposure to the pesticide. Scientists further discovered that those with comparatively higher levels of exposure weighed less at birth and at ages 2 and 3, and were more likely to experience persistent developmental delays including hyperactivity and cognitive, motor and attention problems. By age 7, the average IQs of children who had been exposed to high levels of chlorpyrifos were lower than children who hadn't been exposed. Three independent investigations published in the journal Environmental Health Perspectives (EHP) have reached similar conclusions, associating prenatal exposure to organophosphate pesticides with IQ deficits in school-age children.
These studies only add to the growing body of research completed over the past several decades on the interactive effects of pesticides on human health and the environment. These studies strongly suggesting that exposure, even low levels, may threaten the health of the general population.
Agricultural workers have a 10-fold higher risk of pesticide-related illness and injury compared to workers in other industries. From 2007 to 2011, a total of 2,606 cases of acute occupational pesticide-related illness and injury were reported in 12 states (Table 1). Rates of illness and injury among agricultural industry workers — 18.6 per 100,000 workers — were found to be 37 times greater than the rates for nonagricultural workers. Insecticides and herbicides are the most common culprits.
According to CDC’s National Institute for Occupational Safety and Health likely underestimates the magnitude of pesticide-related illness and injury, since many workers never pursue medical care nor call the authorities.
The Food Quality Protection Act set a new safety standard for pesticides and fungicides when it was passed in 1996, requiring the E.P.A. to determine that a chemical can be used with “a reasonable certainty of no harm.” The act also required the agency to take the unique vulnerabilities of young children into account and to use a wide margin of safety when setting tolerance levels.
The phenomenon known as pesticide drift means that the threat posed by pesticides such as chlorpyrifos isn’t limited to the fields where they’re used. With Chlorpyrifos no longer headed for the list of banned chemicals, even crops that do not use it can be affected, as in the case of Dan Andrews Farms cabbage field.
As the Bakersfield incident reminds us, the health of farmworkers and community members are at risk in areas where these chemicals are used. It is critical that the scientific and medical community speak out loudly against the EPA’s negligence in shelving the proposed ban on these dangerous compounds. Vulnerable workers and children will continue to suffer the consequences if we don’t.
Daniel Turner-Lloveras is a physician at Harbor-UCLA Medical Center.
[Photo by benketaro via Flickr.]