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Widespread Illegal Pesticide Use Uncovered in Washington State

By Alexander Beadle

Published: Nov 08, 2018   
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Over 40 percent of cannabis samples tested by the Washington State Department of Agriculture (WSDA) in the 16-month period between March 2017 and July 2018 contained unacceptable levels of legal or banned pesticides, The Stranger reports.

Data released by the medical marijuana advocacy group, Patients United, details a total of 387 pesticide tests carried out on cannabis samples by the Washington State Department of Agriculture (WSDA) laboratories on behalf of the state’s Liquor and Cannabis Board (LCB). The data reveals that 43 percent of the samples tested contained either banned pesticides or illegal levels of state-approved pesticides. Banned pesticide use accounted for 37 percent of the 387 tests, with the rest accounted for by high levels of approved pesticides. In one case, Patients United says, a sample contained over 90 times the allowable limit of a certain pesticide.

Pesticide Testing in Washington State

Washington state has traditionally being a groundbreaker in terms of cannabis legislation - with the state’s first medicinal cannabis legislation being passed by ballot measure as early as 1998. In 2012, Washington also became the first in the country, alongside Colorado, to legalize recreational cannabis use.

Despite this, the state’s current cannabis pesticide testing laws lag behind those used in other states with active cannabis markets. In California, which has arguably the strictest cannabis testing programme in the United States, cannabis pesticide testing is mandatory for both recreational and medicinal cannabis. As well as pesticide testing, medicinal and recreational cannabis samples in California are also tested for residual solvents, processing chemicals, and microbial infection risk. At the end of 2018 California also plans to introduce mandatory tests for mycotoxins and heavy metals, as well as full terpenoid characterization and water activity testing for edibles.

Contrastingly, in Washington state, pesticide testing is only mandatory for medicinal cannabis, and even then the testing only screens for a set list of unapproved pesticides. For recreational cannabis, Washington state mainly relies on randomized testing, with additional tests carried out in the event of a complaint or report being given to state officials by consumers or cannabis business employees.

Reaction to the WSDA Test Results

In an e-mail to The Stranger about the WDSA test results, Brian Smith, a spokesperson for the LCB, referenced this testing procedure when responding to the findings of the Patients United group. While he did not protest the findings of the report, Smith did say that due to the current complaint-motivated testing system that is used by the LCB this “could result in positives for pesticides results in greater frequency than the average population [of cannabis samples]”. Hector Castro, speaking on behalf of the WSDA, reiterated that while the WDSA does conduct pesticide testing for the LCB, their labs are not tasked with providing any analysis of the testing results.

Following the report, Patients United are urging the LCB to reconsider their pesticide testing system by adopting pesticide testing as a mandatory requirement for cannabis producers in the state. John Kingsbury, a prominent cannabis advocate and organizer with Patients United, labeled the pesticide contamination situation a “public health emergency” in a letter sent to the LCB, which was uncovered by The Stranger

“Likely tens of thousands of Washington consumers are consuming regulated recreational cannabis during any one day. With pesticide testing failure rates of 30-43%, it is statistically guaranteed that those consumers will consume a product with illegal amounts of pesticides in it every third use,” Kingsbury postulated later on in the letter. 

The 30% figure mentioned by Kingsbury is thought to come from a separate pesticide report conducted by the cannabis lab Confidence Analytics, which found illegal pesticide contamination on 30% of the products randomly tested in their study. Figures from this Confidence Analytics study were reportedly included in the Patients United letter to the state. 

While Analytical Cannabis has been unable to secure a copy of this report to confirm the data, an additional report from Trace Analytics, commissioned by the Clean Cannabis Association, did find that of their randomly selected samples, roughly 3 in 10 cannabis flower samples contained some levels of illegal pesticides, with this figure rising in cannabis concentrate products.

The Future of Pesticide Testing in Washington

A spokesperson for the Department of Health (DOH), Kristen Maki, told The Stranger that the DOH has been made aware of the Patients United report and that as a consequence the DOH is currently “having ongoing discussions” with the LCB surrounding cannabis product testing. 

The LCB recently filed an inquiry into the possibility of making major changes to its cannabis legislation, which could see the introduction of mandatory pesticide testing for all cannabis products, as well as reform of other matters such as packaging and labeling, and an adjustment to the pass/fail criteria for cannabis quality control. The inquiry ended at the end of October and an announcement of any resultant proposed rule changes is expected imminently.

Alexander Beadle

Science Writer

Alexander Beadle has been working as a freelance science writer since 2017 and has covered the cannabis industry for Analytical Cannabis since 2018. He has also written for our sister publication, Technology Networks, and the cannabis industry consultant firm Prohibition Partners, among others. Alexander holds a Master's in Materials Chemistry from the University of St. Andrews, where he won a Chemistry Purdie scholarship, and conducted research into zeolite crystal growth mechanisms and the action of single-molecule transistors.


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