What WDSA Does Part 1: How cannabis testing helps ensure proper pesticide use

Amber Betts
WSDA Communications

Michael Romias breaks down
cannabis samples into a fine powder
after cryogenically freezing them.

The Washington State Department of Agriculture (WSDA) is widely known for supporting farmers, inspecting commodities, ensuring food safety, and managing the types of pesticides used across the state.

But as someone new to the agency, I am learning that WSDA does so much more.

One example right in downtown Yakima can be found at the Chemical and Hop Laboratory, part of WSDA’s Plant Protection Division. Like any lab, WSDA’s is filled with beakers, canisters of various gases, and an array of scientific equipment that can be daunting to the non-scientist.

One of the activities at this lab is testing various crops to identify the types of pesticides used during production, ensuring proper pesticide use. Recently, those crops have included cannabis.

On a recent visit, I was able to watch a chemist test samples of cannabis to ensure that growers are using the proper pesticides on their crop.

Samples are frozen with
liquid nitrogen in a
process called
"cryogenic grinding."

Since 2016, WSDA has tested cannabis under an agreement with the Washington State Liquor and Cannabis Board (WSLCB), which provides funds for the tests and the samples being tested.

Frozen and broken down
samples head to testing,
where the pesticide used
is extracted from
the sample. 

Cannabis is not a federally recognized crop, so the EPA has never identified any pesticide products specifically for use in cannabis production. However, WSDA, which regulates pesticides used and distributed in Washington, developed a list of pesticides allowable for use in cannabis production.

To test cannabis, chemists freeze samples with liquid nitrogen. Cool, right? This allows them to chisel the samples into a fine powder from which they can extract the pesticide used on the product and use the mass spectrometer (yes, like in the cop shows) to determine if the pesticides meet WSDA criteria for use in cannabis production. There are 331 pesticide products allowed for use on marijuana, as long as all applicable label directions are followed. When testing, WSDA tests for the presence of 230 active ingredients, and the majority of them are not on the allowed list.

A sample is shown right after
being frozen and broken down
into powdery form, perfect for extracting
the pesticide used to grow the crop. 

WSDA then provides those results to the WSLCB, which regulates Washington’s cannabis industry and will determine next steps after reviewing test results.

The testing conducted at the Chemical and Hop Laboratory is one way that WSDA fulfills its mission to protect public health, Washington's food supply, the agriculture industry, and the environment. As a new media relations coordinator for the agency, I plan to share more stories about the work of WSDA and its staff, so look out for the next edition of “What WSDA Does.”