Update for WA cannabis licensees and stakeholders regarding  recent detection of dichlorodiphenyldichloroethylene (DDE) contamination found in certain products

This message is to update cannabis licensees and stakeholder regarding the recent detection of dichlorodiphenyldichloroethylene (DDE) contamination found in certain products. DDE is a remnant product of DDT — a pesticide that was banned in the United States in the 1970s.


In brief, the Liquor and Cannabis Board (LCB) has been randomly testing cannabis for pesticides since 2018. The LCB contracts with the state Dept. of Agriculture (WSDA) laboratory in Yakima to perform pesticide tests. The WSDA lab can currently detect 243 pesticides. Its testing includes DDT and its breakdown products such as DDE.

Recently, we recognized a pattern of failures from the WSDA test results that were tied to a specific region in north-central Washington. The WSDA lab reports are sent to LCB chemists for centralized and subject-matter-expert review. One of our chemists recently identified a pattern, isolated to a small geographic area, and suspected that the soil might be contaminated from past use (decades ago) of DDT. Outside of this region of concern, DDE contamination above action levels has not been detected in hundreds of previous cannabis product tests conducted by WSDA from any other part of the state.

There are 18 licenses (16 producers and 2 processors) within the area that is suspected of contamination. Upon detection of cannabis products containing DDE, the LCB placed an administrative hold on five licensees whose products came back with action levels exceeding allowable limits of pesticides – in this case, DDE. The LCB this week collected products from the 13 other licensees and the Department of Ecology collected soil samples. The licensees in the affected area that have failed random testing have been asked to initiate a recall of these products.

LCB officers have also purchased retail products to test for contamination. The LCB this morning received the first results of these product tests. All six product tests showed positive for DDE above current action levels. The stores have voluntarily pulled these products from their shelves.

Next Steps

Earlier today, LCB leaders and subject matter experts from the Departments of Ecology, Health, and WSDA held three constructive meetings individually with: affected licensees, industry trade groups and concerned legislators. During the discussions, the LCB discussed its authority to ensure that cannabis products in Washington State are safe and do not contain unapproved pesticides. Experts from the other agencies fielded questions that fell within their purview. Going forward:

  • Rules in Place. The LCB has existing rules in place that govern the use of pesticides. These rules clearly state which pesticides are allowed and the steps the agency will take to remove cannabis products from the marketplace containing unapproved pesticides that exceed action levels. The LCB will continue to exercise this authority to protect the integrity of the regulated system. WACs 314.55.084, 314.55.102, and 314.55.225.
  • Emergency Rules Not Currently Necessary. Last week’s message to licensees indicated that the agency intended to bring forward emergency rules to address testing for DDT, DDD, and DDE. Prior to this week’s Board meeting, LCB staff concluded that existing rules suffice to address products containing unapproved pesticides. Emergency rules are not necessary at this time. The agency will continue to evaluate and monitor the situation.


As test results return from the WSDA lab over the coming weeks, the LCB will take the appropriate actions to ensure the contaminated products are recalled from the marketplace. Licensees will be asked to institute a recall of contaminated products. The LCB posts notices of recall on its website. Other relevant public documents will soon be made available on the LCB website as well as via public record at publicrecords@lcb.wa.govThe LCB recognizes the hardship and concern faced by affected licensees as well as the potential health and safety concerns of consumers. It is our hope to resolve this concern quickly, remain transparent with our licensees and stakeholders, and to take the appropriate actions to minimize impact overall.

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