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Recall: Recent Developments Regarding Pesticide Use on Cannabis in Colorado

By: David Feeder, Esq.

Use of pesticides (and/or herbicides and fungicides) in the legal cultivation of cannabis in Colorado has received significant attention from state and local regulators over the past year. The uncertainty and continuously-changing landscape with regard to this issue have caused wide-spread concern within the marijuana industry, and marijuana businesses should be aware of the issues and risks associated with use of pesticides on Cannabis.


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Pesticides are regulated at the federal level by the U.S. Environmental Protection Agency (EPA). The EPA determines whether pesticide products can be applied to different plants or crops, and it approves labeling for each pesticide, indicating which plants or crops that particular pesticide can legally be applied to, along with the allowed amount. However, because Cannabis is a federally illegal Schedule I narcotic, the EPA has not approved the use of any pesticide on Cannabis. Use of a pesticide inconsistent with the approved product labeling is considered an “off-label” use that is prohibited both federally and in Colorado by the Colorado Pesticide Applicators’ Act (CPAA).

This dynamic placed the Colorado marijuana industry in a difficult situation, with limited options for pest control, and no guidance at either the federal or State level. The situation escalated in March 2015, when the Denver Department of Environmental Health (DDEH) quarantined tens of thousands of Cannabis plants based on pesticide concerns. In July 2015, the Colorado legislature amended the CPAA to prohibit local governments from utilizing their police power to “directly or indirectly regulate or prohibit the application of pesticides…including in connection with the cultivation of marijuana.” (C.R.S. § 35-10-112.5(3)(b))

In November 2015, Colorado Governor John Hickenlooper issued an Executive Order that declared marijuana contaminated by an off-label pesticide as a threat to public health and safety – effectively a “zero tolerance” policy with regard to pesticides and Cannabis. Based on this authority, both local (DDEH) and state (Colorado Department of Revenue, Marijuana Enforcement Division) regulators have taken numerous actions against companies that produce marijuana or utilize it in their products. These actions include the following:

  • Administrative hold orders on products.
  • Orders to test product.
  • Orders to recall product.

Such orders can and have had crippling economic impacts on affected companies, with even more serious potential actions such as destruction of product and adverse impacts on marijuana licenses. There are several practical, scientific and legal issues that are implicated by regulatory action of this nature, including the following:

  • The scope of local regulators’ authority to indirectly regulate or prohibit pesticide use under the guise of their police powers.
  • Deficiencies in the collection of samples of marijuana product for testing that could cause contamination or inaccurate results.
  • Difficulties in testing marijuana products for pesticides.
    • There are currently no laboratories certified by the State to perform pesticide testing of marijuana other than the Colorado Department of Agriculture’s (CDA) lab.
    • Recently regulators have utilized a “composite testing” approach, where samples from plants in multiple grow rooms are combined together and tested as a single batch.
    • Testing marijuana products is a difficult scientific process, and additional difficulties in the process exist for testing of products such as marijuana concentrates.
  • The lack of realistic or consistent standards for pesticide use on Cannabis.
    • The “zero tolerance” policy established by the Governor’s Executive Order creates an extremely difficult situation, as some pesticides deemed a health and safety risk for Cannabis are allowed on other products, and are therefore present in the environment. This creates the possibility of “contamination” even when a grower does not utilize the pesticide.
    • The DDEH has utilized differing standards, and, instead of employing the Governor’s “zero tolerance” approach, it currently considers Cannabis to be contaminated if the amount of pesticide residue exceeds the lowest level allowed on any food product.
  • The lower “burden of proof” utilized by regulators in making determinations of pesticide “contamination.”
    • Due to the expressed concerns over public health and safety, state and local regulators have deemed marijuana products “contaminated” with pesticides if they determine that it is simply “likely” that the product contains unapproved pesticides, even if the product is only “potentially” contaminated.

Recent developments provide Colorado marijuana businesses some guidance, but they also create more cause for concern:

  • On March 25, 2016, the DDEH issued an Industry Bulletin, informing that it is “transitioning to an enforcement approach for the marijuana industry that is consistent with the other industries it regulates” beginning on April 15, 2016. Under the DDEH’s newly-announced approach, “marijuana products that are found to be potentially contaminated with unapproved pesticide residues may be condemned by [DDEH] and ordered destroyed.” In a significant shift from DDEH’s prior approach, it will no longer utilize laboratory testing to monitor and evaluate batches of potentially contaminated marijuana plant material for potential release.
  • Effective March 30, 2016, the CDA published Rules and Regulations regarding “The Use of Pesticides in the Production of Cannabis.”
  • Also effective March 30, 2016, and consistent with the CDA’s Rules and Regulations of the same day, the CDA published a list of pesticides allowed for use in Colorado in Cannabis production.
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