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What You Need to Know About the Chlorpyrifos Ban in California

What is chlorpyrifos?

Chlorpyrifos is an active ingredient in insecticides used primarily to treat agricultural food and feed crops. Chlorpyrifos is a “broad-spectrum, chlorinated organophosphate insecticide, acaricide and nematicide.”[1]  It was first registered for use in the United States in 1965. Chlorpyrifos was designated as a restricted material by the DPR in 2015 and has now been banned from use in California.[2]

Why has California banned chlorpyrifos?

Studies have shown connections between chlorpyrifos and developmental harm to infants which future studies show persisted into childhood. Other studies have shown contradictory results; however, the methodologies and conclusions were called into question. Three studies published in 2017 & 2018 have since shown that chlorpyrifos does in fact cause “decreased learning, hyperactivity and anxiety in rat pups.”[3] Upon careful consideration of the new studies, the California Department of Pesticide Regulation decided that the risks could not be mitigated, and moved to ban the product entirely.

Are there alternatives to chlorpyrifos?

CA DPR has established a workgroup to “develop short and long term action plans to identify and develop safer, more sustainable alternatives to chlorpyrifos. The work group will leverage the work of experts from across the globe to identify and develop pest management tools.”[4] Work is underway, and results can be expected in the spring of 2020.

When does the ban go into effect?

Registrations for products with chlorpyrifos as the active ingredient were made inactive on January 1, 2020. Distribution by California dealers ceased on February 6, 2020. However, possession and use does not have to cease until December 31, 2020.[5]

What are the conditions for use of chlorpyrifos through December 31, 2020?

Application limitations of chlorpyrifos include “a ban on aerial spraying, quarter-mile buffer zones and limiting use to crop-pest combinations that lack alternatives.”[6] The full description of interim permit conditions can be found here:

What products are affected by this rule change?

The full list of affected products can be found in this CA DPR notice:

If I still have affected products by December 31, 2020, what should I do with them?

“Do not throw unused pesticides in the trash. Check with your local solid waste management authority, environmental health department or county agricultural commissioner to find out whether your community has a household hazardous waste collection program.”[7]

Sources and Further Reading:


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