Hazardous Pesticides in Legal Cannabis

An illustration of a person in a white hazmat suit with a backpack-style sprayer on their back. They are standing and spraying on an aqua background.

The EPA has refused to provide pesticide regulations for the cannabis industry (and with Andrew Wheeler at the helm, that may be a good thing). So states have to create their own regulations by banning and “recommending” the pesticides they deem appropriate. In order to start addressing the issue, public health researchers at Oregon State University surveyed pesticide use in Oregon between 2016-2017, focusing on worker safety.

Steel yourself, it’s bad news.

Fifty pesticides were identified, with nine of these considered highly or extremely hazardous by the World Health Organization. Two of the highly hazardous chemical are allowed in California’s cannabis: oxamyl and cyfluthrin. But it gets worse. Medical products that failed had four times more pesticides than recreational products, on average. About 2700 recreational samples failed, as opposed to 900 from the medical market (this may reflect different market sizes). Concentrates had the lowest pesticide levels.

Previous research showed that over 1/3rd of workers in cannabis industry suffer from handling pesticides. The current study only examined batches that failed pesticide testing “due the fact that laboratories do not report the pesticide name nor concentration for samples that do not fail.” This is a separate problem that ought to be addressed legislatively. But remember that if the regulations and a legal market didn’t exist, these contaminated products would have been sold, unbeknownst to consumers. About 6.7% of recreational products fail pesticide testing in Oregon, and almost half of all extracts tested had an unacceptably high pesticide concentration.

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Adrian Devitt-Lee, Project CBD's chief science writer, is pursuing his PhD in Mathematics at the University College of London.