What is Chlorpyrifos?

Chlorpyrifos has been in use since 1965 and is currently one of the most widely used pesticides in the United States. Chlorpyrifos is often applied to foods crops like corn, soybeans, apples, broccoli, and asparagus.

Why is the EPA Banning Chlorpyrifos?

Several epidemiological studies have linked prenatal and early life chlorpyrifos exposure to adverse health outcomes in children such as low birth weight, reduced IQ, autism, and learning disabilities. In 2015, the Obama administration began taking steps to revoke the use of this pesticide, but in 2020, the Trump administration halted this process and kept chlorpyrifos on the market. Numerous environmental organizations, health advocates, and groups representing farmworkers have since petitioned the EPA to reverse this Trump-era decision. In August 2021, in a sweeping order by the Ninth Circuit Court of Appeals directing the EPA to stop the use of this pesticide unless its safety could be demonstrated, the Biden administration will prohibit the application of chlorpyrifos on food crops by February 2022.

The ban on chlorpyrifos was not instituted via the standard process, in which the EPA publishes a draft rule, takes public comment, and then publishes a final rule. Because the epidemiological literature has been available for over a decade, the court order states that the rule will be published right away in final form, without the opportunity for public comment. This rule will also rescind any existing tolerances for chlorpyrifos, which indicate an amount of a pesticide that is allowed on food (United States Environmental Protection Agency, 2021).

Epidemiological studies, which are observational studies on select groups of people over time, suggest associations between exposures and outcomes but are not sufficient to say that there is causation since it is not possible to control for bias (Bloomberg Environment & Energy Report, 2021). In the coming months, challenges may ensue as several chemical companies have already or will soon face toxic tort cases. 

Christopher Novak, the President and CEO of CropLife America, an agricultural services company, describes this pesticide as “relied upon by farmers to control a variety of insect pests and by public health officials who work to control deadly and debilitating pests like mosquitoes” (The New York Times, 2021). However, the EPA Assistant Administrator for Chemical Safety and Pollution Prevention, Michal Freedhoff, states that the sudden and unusual move “speaks to the impatience and frustration that the courts and environmental groups and farmworkers have with the agency” (The New York Times, 2021).

Chlorpyrifos will still be permitted for uses not related to food, such as on golf courses and turf, on utility poles and fence posts, and on cockroach and ant treatments. Per the usual EPA guidelines on pesticides, users should always read and closely follow label directions. For chlorpyrifos, this includes wearing personal protective equipment such as chemical-resistant gloves, coveralls, and respirators (United States Environmental Protection Agency, 2021).

How Can Paustenbach and Associates Help?

If you or your client works with chlorpyrifos and needs assistance, we are a team of highly trained toxicologists and epidemiologists who have extensive experience conducting risk assessments and reviewing epidemiological literature. If you want to learn more about how we can help you or your client, please contact our chlorpyrifos team leader, Ms. Emma Wu, MS, at ewu@paustenbachandassociates.com.

EPA Takes Action to Address Risk from Chlorpyrifos and Protect Children’s Health – https://www.epa.gov/newsreleases/epa-takes-action-address-risk-chlorpyrifos-and-protect-childrens-health