Lack of federal regulations makes managing pesticides challenging in the US

States that have legalized cannabis have to come up with their own rules for managing pesticides

In the United States, pesticides are regulated by both the federal and state agencies, but because cannabis remains illegal at the federal level, states are left to manage how to regulate pesticide use on cannabis.

With a federal framework that criminalizes cannabis and an informal policy that de-prioritizes enforcement against those following state law, the U.S. finds itself in a difficult position. This means that states are implicitly allowed to legalize cannabis production, while at the same time remaining blocked from the assistance of federal agencies such as the EPA and FDA.

This concern is addressed by a new report published in the International Journal of Drug Policy by Dr. Todd Subritzky, Simone Pettigrew and Simon Lenton.

The authors analyzed the situation in Colorado, which in 2014 was the first jurisdiction in the world to legalize the production and commercialization of recreational cannabis. A task force report that predated the legislation raised concerns about pesticide contamination, pointing to the problems plaguing the existing black market.

The incentive for using pesticides is understandable, as cannabis is vulnerable to parasites (see a lift report were we analyzed the recent case of roundworm infestations in China). In addition, even under legal circumstances, insurance companies usually refuse to cover damages incurred by pests.

But pesticides can pose a significant threat to public health. A 2013 study showed that smoking through a water pipe can filter pesticide residues from smoke, whereas unfiltered glass pipes allow the transfer of 60 to 70% of these to smoke. More concerning is the case of concentrated extracts used for oils, waxes, and edibles. A 2015 report from the Cannabis Safety Institute showed that cannabinoid extraction processes intensify the levels of pesticides in the final product, up to 10 times the original concentration.

Two common pesticides found to be 10x more abundant in concentrates than in cannabis flowers (source)

The use of other products—such as plant growth regulators—that are not traditionally seen as pesticides is also of concern. These are used to produce shorter and more uniform plants with a higher density of flowers per plant, and are common in commercial and personal cannabis crops. Often, growers are unaware of their use, as they might not be listed on the labels of commercial cannabis fertilizers. According to a few studies referenced by the authors, plant growth regulators have been linked to problems of infertility, liver damage and cancer. Currently no growth regulator is accepted for human consumption.

One of the major issues that still goes unresolved by the Colorado legislation is the listing of pesticides and other chemicals that are allowed or forbidden for cannabis cultivation. It is usual for states to take assistance from federal agencies in this matter, but as stated earlier, this is not permitted for cannabis. As Whitney Cranshaw, a pesticide expert from the Colorado State University explained to The Cannabist: “There is no federal agency that will recognize this as a legitimate crop. . . . Pest-management information regarding this crop devolves to Internet chats and hearsay.”

A difficult balance must be struck between protecting crops from pest attacks and ensuring the public health of consumers and plant cultivation workers. One of the main advantages of legalization is that issues such as this one come out in the open, where they can be tackled with society's best resources.

Featured image by Jeff Vier.

In this article


Join the Conversation