By Carey Gillam
On December 2, the U.S. Environmental Protection Agency (EPA) announced yet another milestone in the convoluted life span of the insecticide chlorpyrifos. Under the deceptive headline “EPA Proposes Rule to Revoke Most Food Uses of the Insecticide Chlorpyrifos,” EPA stated that it is improving environmental protection by revoking all usages of chlorpyrifos except for 11 food and feed crops. The proposal was deemed “unconscionable” by Beyond Pesticides executive director Jay Feldman in an article in The New Lede.
EPA claims this plan would reduce annual chlorpyrifos application by 70% compared to “historical usage.” Chlorpyrifos is a known neurological and reproductive toxicant. EPA has been cutting back on approved uses for years but is far behind other environmental authorities—the European Food Safety Authority and Thailand have banned it altogether, and California has banned its agricultural use.
The trouble with EPA’s latest attempt is that it does nothing to clarify and rationalize EPA’s process, and it will not protect the public, because those 11 remaining products are among the most extensively grown and used in the world: soybeans, sugar beets, cotton, wheat, apples, citrus fruits, strawberries, alfalfa, cherries, peaches, and asparagus.
Chlorpyrifos is an organophosphate chemical. These compounds inhibit acetylcholinesterase (AChE), which regulates nerve signals in all invertebrates and vertebrates. Thus, there is no justification for the assumption that what harms insects will not harm humans. The lethal dose in newborn rats is 100 times lower than in adult animals. EPA has known for decades that chlorpyrifos (introduced in 1965) is a neurotoxicant, especially at crucial developmental stages, such as prenatal and infancy phases when the human brain is growing at its fastest rate. In 2016 EPA said children between one and two years old were being exposed via food to 14,000% of the risk concern level.
While AChE inhibition produces well-documented problems including attention and IQ deficits, lower birth weight, working memory loss, and motor development delays, there has also been evidence at least since the 1990s that chlorpyrifos also affects other neural pathways. For example, it can produce changes not just in the brain but in the digestive system.
The EPA’s new policy stems from decades of waffling and delay, in which industry influences sowed doubt about epidemiological evidence of health harms and emphasized uncertainties about data, particularly regarding drinking water exposure. Activists and agricultural workers, mostly in California, grew tired of waiting for health protections and filed suit against the EPA in 2007. It took until 2021 for the case to be decided by the Ninth Circuit Court of Appeals.
That court, frustrated by EPA’s indecisiveness and contradictions, ordered the agency to decide, within 60 days of its ruling, how toxic chlorpyrifos is and either revoke its food residue tolerances or declare that they are actually safe. In response, and to the surprise of the registrants and growers, EPA issued a final rule in August 2021, revoking all tolerances for chlorpyrifos. This upset the pesticide industry, which then backed a suit by growers’ associations in the Eighth Circuit Court of Appeals.
The Eighth Circuit reversed the Ninth Circuit’s decision in November 2023 and remanded the case back to the EPA for “further proceedings.” See our November 2023 Daily News analysis. In the Eighth Circuit case, plaintiffs emphasized how unreasonable the Ninth Circuit’s 60-day deadline appeared, despite the fact that the Ninth Circuit litigation had been dragging on for 14 years.
EPA’s most recent move is clearly the result of industry pressure. Interestingly, in light of recent political shifts, CropLife International’s (chemical industry’s trade group) 2022 amicus brief in the Eighth Circuit litigation argued that the EPA had failed to use its statutory authority properly—that is, a supposedly independent executive branch agency had the legal standing to make firm decisions based on its own expertise—an approach that does not comport with this year’s U.S. Supreme Court decision in Chevron v. Natural Resources Defense Council weakening this very authority.
There is a great deal of murkiness in EPA’s documents, which becomes nearly impenetrable in some of the agency documents issued after the Ninth Circuit case concluded. However, both cases focused heavily on two relatively clear EPA documents from 2016: the Chlorpyrifos Revised Human Health Risk Assessment for Registration Review and the Chlorpyrifos Refined Drinking Water Assessment for Registration Review. These two documents indicate firmly that EPA had serious worries about dietary exposures, which include both food and drinking water, for many years.
The Eighth Circuit plaintiffs tried to keep consideration of residues in food separate from drinking water exposures, even though the Ninth Circuit panel had noted that the Federal Food, Drug and Cosmetic Act requires considering food and water exposures together. EPA has previously explained its approach with a “risk cup” metaphor, saying “each use of the pesticide contributes a specific amount of…risk to the cup….[A]s long as the cup is not full, meaning that the combined total of all estimated sources of exposure to the pesticide has not reached 100% of the [tolerable daily exposure over a lifetime], EPA can consider registering additional uses and setting new tolerances. If it is shown that the risk cup is full, no new uses could be approved until the risk level is lowered.” In the Revised Human Health Risk Assessment, EPA stated that “this assessment indicates that dietary risks from food alone are of concern” and “after accounting for food exposures” there is no room for water in the risk cup. Moreover, based on model simulations, the Refined Drinking Water Assessment found that concentrations in drinking water might exceed 100 μg/L, an unsafe level. The World Health Organization’s 2022 guideline for a maximum level of chlorpyrifos in drinking water is 30 μg/L. Yet the Eighth Circuit plaintiffs repeatedly suggested that data about drinking water exposures was unreliable, convincing EPA to rely on water modeling data provided by registrants.
Trying to separate food from water exposure is bizarre because combined exposures affect everyone, and the people most exposed to chlorpyrifos—workers and other people living in agricultural areas—certainly must consume both food and water (like everyone else), and their regions certainly qualify as “vulnerable watersheds.”
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