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Colorado cannabis cultivators will have to pass mandatory pesticide testing starting Aug. 1 in order to bring their flower to market, which may be a new process to many growers.

“It has not been a mandatory test,” Ryan Randolph, lab director for AgriScience Labs’ Western Slope location, told Cannabis Business Times. “Some of the labs have been offering pesticide testing as a voluntary test that producers could do. The volume on the tests on a voluntary basis has been pretty low because if you do fail that test, you will have to deal with potentially destroying that batch of product.”

The state has identified 13 specific pesticides that labs will be required to test for:

• Abamectin
• Azoxystrobin
• Bifenazate
• Etoxazole
• Imazalil
• Imidacloprid
• Malathion
• Myclobutanil
• Permethrin
• Spinosad
• Spiromesifen
• Spirotetramat
• Tebuconazole

Colorado’s governor originally signed an executive order that issued a zero-tolerance policy for any pesticides on cannabis, Randolph said. This can be difficult to implement, he added, because labs can only detect down to a certain level of pesticides—if there is a miniscule amount in a batch, they may not be able to see it.

“We can detect pretty low, but there’s room for a lesser amount than what we can detect,” Randolph said. “Then you get into, OK, so we’re going to have eight or nine different labs that are all running pesticide testing, and each one has a different method with a different instrument and different levels of sensitivity. So, if I go and invest in a really nice instrument [with] really low detection limits, then I’m going to be failing a lot more customers than another lab [that’s] invested in a less sensitive instrument and has higher detection limits.”

To level the playing field, the Colorado Department of Health and Environment held working group meetings to allow stakeholders from the industry to discuss testing issues, and they determined that there should be a set detection limit for each of these 13 pesticides, and that labs need to be able to achieve this detection limit to be certified for pesticide testing. 

If a sample has pesticides below the legal limit, it passes; if not, it fails.

Colorado cultivators are responsible for collecting the samples and submitting them to the labs, although AgriScience Labs and several other labs in the state offer transport to pick up the samples and bring them to the lab, Randolph said. The Colorado Department of Health has developed standard operating procedures for how the samples must be collected and the amount of product that needs tested, he added.

Pesticide testing must be performed on every harvest batch a cultivator produces, unless they do process validation, in which the grower has every single batch tested for a certain period of time. Once all the various tests are passed over that period of time, testing on every batch is not required—the cultivator can submit one batch every month and maintain the process validation for 12 months, as long as the company continues to pass each round of testing.

“If you have used pesticides in the past in your grow facility, those pesticides will be in your HVAC system. They’re on the walls, they’re on the floor—your whole environment might be contaminated.”

-Ryan Randolph, Lab Director, AgriScience Labs

Typical turnaround time for lab testing is two days, Randolph said. If a cultivator fails pesticide testing—or any form of testing—in Colorado, he or she can do two additional retests. If one of those retests fails, the batch must be destroyed, but if both retests pass, the product can be sold. This process guards against the possibility of a false positive, Randolph said, which can result from tiny concentrations of contamination in the lab, which generally register in the low parts per billion range, Randolph said.

AgriScience Labs uses a two-stage testing process to prevent it from reporting a false positive, he added. In the first stage, upon receipt of the sample, the lab performs an initial screen, which alerts them if there are contaminants present that could cause a fail.

“This is really a qualitative analysis where we just run the sample to see if there is a signal or not a signal,” Randolph said. “The answer is a binary yes or no.”

“For the most part, we would expect our customers are going to be passing these tests because the implications of failing are pretty harsh,” he added. “Normally we don’t see a signal in that initial screen and we can be confident that there’s nothing there to cause a fail. But if there is a signal there, then we’re required to quantify, to determine how much of that pesticide is there.”

That brings the lab to the second stage of the testing process, which quantifies how much of a particular pesticide is present in the sample. “Quantitation requires more investment of labor and additional controls that we have to run with the tests,” Randolph said. “As long as we can pass them on the initial screen, we can be done with the sample, but if we do see that signal, then we go back to the original data pull and we repeat the analysis—this time in triplicate—and we’re going to also include a whole bunch of extra controls in the analysis.”

AgriScience keeps certified pesticide-free cannabis in its labs as a negative control, and it adheres to calibration standards. Cannabis extract that is fortified with a pesticide in five different levels of concentration is used to calibrate the instrument’s response, Randolph said. “We also include … positive controls that are spiked with pesticides with three different levels,” he said. “We know what those concentrations are and then we quantitate them back to make sure that we have accuracy in our calibrations. It’s an independent verification of that calibration.”

These processes allow AgriScience to be confident that if it does report a fail on pesticide testing, it has done everything it can to confirm that the fail did not result from a false positive, Randolph said.

“I don’t know what percentage of cultivators are going to start failing tests when pesticide testing goes online, but it serves to say that some percentage of them will,” he added. “If you have used pesticides in the past in your grow facility, those pesticides will be in your HVAC system. They’re on the walls, they’re on the floor—your whole environment might be contaminated, and it might be really hard to clean it out and start growing anew and pass all these tests. So, it might put some of the cultivators out of business if they can’t pass the tests.”

Cultivators should consider taking swabs of their HVAC systems and asking labs if they can test the swabs to see if any contaminants exist in the facility, Randolph said. “It’s a concern that you might fail,” he added. “If you run your bud samples for pesticide testing and it fails, then that does have to be reported to the Marijuana Enforcement Division. So, just know that there is a risk in running the samples, but come Aug. 1, you’re going to have to run them anyway, so you might as well go ahead and find out where you’re at.”

Now is also the time for cultivators to invest in integrated pest management systems, Randolph said, if they haven’t already. “I know there are a lot of other cultivators that have invested significantly in making sure that they don’t need to use pesticides in order to grow quality product,” he said. “Some of them use integrated pest management systems where you might have biological controls.”

And those who are playing by the rules have nothing to fear, Randolph added.

“I think that those cultivators who have made that investment and have really had a dedication to providing clean, quality product to consumers—you’ll see them benefit in the implementation of pesticide testing,” he said. “I think that they will be able to pass and bring their product to market and there may be slightly less competition in the market if others are not able to pass the testing.”

Photos courtesy of AgriScience Labs