US aims to reinstate chlorpyrifos insecticide ban

The US Environmental Protection Agency (EPA) has proposed to ban most food uses of the organophosphate insecticide chlorpyrifos. In August 2021, the agency had finalised a ban on chlorpyrifos in all food crops, but a federal appeals court reversed that decision in November 2023, calling it ‘arbitrary and capricious’ and arguing that the EPA could have instead implemented a partial ban.

Chlorpyrifos remains in use mainly for agricultural purposes, after  household uses were banned decades ago. The EPA’s latest action exempts 11 crops from the ban – alfalfa, apples, asparagus, tart cherries, citrus, cotton, peaches, soybeans, strawberries, sugar beet and wheat – with limits on allowable residues in those crops.

At high levels, organophosphate pesticide exposures can result in neurological effects like tremors, fatigue and nausea. Chlorpyrifos has also been linked with neurodevelopmental effects indicating it could impact the development of the nervous system during pregnancy and childhood.

The EPA, latest assessment determined that the current aggregate exposures from use of chlorpyrifos do not meet the legally required safety standard of reasonable certainty that no harm will result from such exposures.

‘EPA continues to prioritise the health of children,’ Michal Freedhoff, assistant administrator for the agency’s Office of Chemical Safety and Pollution Prevention, stated on 2 December. ‘This proposed rule is a critical step forward as we work to reduce chlorpyrifos in or on food and to better protect people, including infants and children, from exposure to chemicals that are harmful to human health.’

In the most recent pesticide residue monitoring report by the US Food and Drug Administration, chlorpyrifos was ranked as the 11th most frequently found pesticide in human food samples.

Chlorpyrifos sales have been banned in the EU since January 2020, over concerns about possible genotoxic effects as well as neurological effects during development and arguing that there is no safe exposure level. Thailand also banned chlorpyrifos in 2020, as did Canada from December 2023. In the UK, the pesticide has been banned since 2016, with the exception of limited use for drenching seedlings.

Several US states – including California, Hawaii, New York, Maine, Maryland, and Oregon – have already independently restricted the use of chlorpyrifos on food, some more tightly than the EPA’s proposal.