What cannabis is teaching us about pesticides and modern agriculture.
By Micah Anderson. An earlier version of this article appeared in Cannabis Confidential.
On October 1st, California is changing the way cannabis is tested for pesticides. The Department of Cannabis Control (DCC) is getting rid of the old system that divided pesticides into Category I and Category II and replacing it with specific action levels for individual pesticides. Beginning in April 2028, the DCC will take the next step, recalibrating many of those limits based on the latest science, adding more pesticides to the testing panel and establishing separate standards for inhalable and non-inhalable cannabis products to better protect consumers.
I generally favor less regulation, particularly in California cannabis, where regulation and taxes have made it extraordinarily difficult to operate legally. But I feel differently when it comes to regulations and standards around contaminants. I think we should have high standards for pesticides, heavy metals and other things that can end up in products people consume, and I don’t think those standards should be weakened as cannabis becomes a bigger industry. If anything, I think the rest of agriculture should be looking at what cannabis has learned and asking whether some of the same standards should apply more broadly.
I feel strongly about this because I have spent more than 30 years growing cannabis and years buying, testing and processing material from farms across California. At LEEF, we have learned that contamination is much more complicated than most people assume. It doesn’t always come from something a cannabis farmer intentionally applied. It can come from neighboring agriculture, soil, water or the history of the land itself.
Cannabis gives us an unusual window into these problems because we test it so aggressively. And after years of seeing what increasingly sensitive testing can find, I keep coming back to a broader question: What might cannabis be telling us about agriculture more broadly?
How I came to care about this
My interest in this subject started long before LEEF and long before California legalized adult-use cannabis. In my early 20s, I became interested in the organic food movement, protested the growing use of genetically engineered crops and became increasingly skeptical of the reliance on pesticides in American agriculture.
Cannabis was part of that thinking too. I believed it had been badly mischaracterized by decades of prohibition and that over time it would become a more normal part of people’s lives. If that was going to happen, I thought we needed to take seriously how cannabis was grown and what people were actually putting into their bodies.
Around the same time, about 20 years ago, I was growing cannabis in Mendocino County under Proposition 215. Like many growers at the time, I bought products from hydroponic stores that I was told would help protect the plants, without much discussion about what was actually in those products or how they should be handled.
One of those products was Avid, which contains the active ingredient abamectin and is now illegal to use on cannabis crops. I was growing indoors at the time, roughly a 20-light operation, and I remember spraying Avid during the winter and getting extremely sick. I spent the better part of two days vomiting.
An older farmer who lived nearby came over to check on me while I was sick, saw what I had been using and basically told me I needed to stop buying products from the hydroponic shops. He told me I should have been wearing proper protective equipment and, more importantly, that I needed to rethink how I was approaching pest management.
He showed me other ways to do it, including neem oil and a much more preventive approach to plant health. We didn’t call it “integrated pest management” at the time, but that is essentially what it was: prevent the problem before it develops rather than waiting for an infestation and reaching for the strongest chemical available. I followed his advice, and the plants were healthier and the results improved.
That experience stayed with me. So did what I was seeing in my own family. My grandfather suffered from Parkinson’s disease and dementia and eventually died from it. My mother has since been diagnosed with Parkinson’s, and one of my closest friends has the disease as well.
I can’t say what caused any of those illnesses, and I don’t pretend that the science gives us simple answers. But between my own experience handling pesticides and seeing Parkinson’s affect people close to me, I became very interested in what we know and don’t know about long-term environmental exposure, including whether pesticide exposure could be contributing to the rise we have seen in some degenerative diseases over the past few decades.
Pesticides exist for a reason. Farmers have to deal with weeds, insects, disease and all kinds of other threats to their crops, and there are times when pesticides are a useful tool. I’m not arguing that all pesticides are bad or that they all carry the same risks. But I do think we should be asking harder questions about what we use, how we use it and what ultimately ends up in the food we eat and the products we consume.
Cannabis growers have had to confront those questions because the testing standards forced us to. Growers have changed their practices, rethought how they manage pests and found ways to produce cannabis that can meet unusually rigorous contaminant standards. Rather than lowering those standards as cannabis becomes a larger industry, I think we should be asking whether agriculture more broadly should be moving closer to them.
Testing before anyone required it
That thinking shaped how we built LEEF. I wanted cleanliness to be core to how we operated, not something we worried about only because a regulator required it.
That meant testing aggressively, including at a time when the regulatory system did not require what it requires today. We wanted our products free of pesticide contamination, problematic microbials, heavy metals and other contaminants we could control.
At one point we were paying roughly $18,000 per liter for verified-clean cannabis oil, a significant premium over conventional oil at the time. We independently tested products and published those results because we believed consumers and retailers would reward that level of transparency.
Instead, it often left us with a more expensive product in a market that did not yet place much value on what we were doing.
The market and the testing environment have changed considerably since then.
I think the standards our industry has learned to meet can become a competitive advantage as cannabis grows. Producing clean cannabis consistently at scale is difficult. The companies that have spent years learning how to do it have built knowledge and capabilities that won’t necessarily be easy for larger agricultural companies to replicate.
And as cannabis becomes more normalized and pesticide contamination gets more attention, I think consumers are going to care more about what else is in the product, where it came from and how it was grown.
Concentrates change how you look at contamination
As we got deeper into manufacturing concentrates, our commitment to clean inputs gave us an unusual perspective on the cannabis supply chain. We have spent years buying cannabis material from farms throughout California and processing that material into concentrated cannabis oil.
In the extraction process, pesticides and other unwanted compounds present in the starting material can become concentrated along with the cannabinoids. The 2024 Los Angeles Times investigation into California’s pesticide problem brought wider attention to this issue. The investigation reported that while extraction can destroy some pesticides, others become more concentrated as cannabis biomass is processed into oil, and that some contaminants can become concentrated many times over in vape oil. The fallout prompted parts of the industry, including LEEF, to raise standards on their own by adopting voluntary CAT 4 testing to screen for a much broader range of pesticides.
We had already been dealing with this problem for years. We would buy cannabis material that looked good and came from experienced cultivators, only to have it fail California’s pesticide testing standards. As our sourcing expanded from Mendocino County into California’s larger agricultural regions, we began seeing the problem more frequently.
Based on our internal experience, a significant percentage of the open-market biomass we have screened has at times failed to meet the pesticide standards required under California’s regulated cannabis system.
Some pesticide failures are exactly what people assume they are: somebody knowingly or improperly applied something to cannabis that should not have been used. That happens.
But that didn’t explain everything we were seeing. In many cases, we were dealing with experienced growers who were trying to do things correctly, and the contamination appeared to be coming from the environment around the farm rather than from something intentionally applied to the cannabis itself.
One thing that really stuck with me was a school project my daughter did a few years ago. She took ten organic produce products from a major grocery chain known for organic and natural foods and had them tested using the same pesticide standards applied to cannabis. Every single one failed. Ten out of ten had pesticide residues at levels that would have caused them to fail under California’s cannabis standards.
It was obviously not a scientific study, and I don’t present it as one. But ten out of ten was hard for me to ignore. After years of seeing what rigorous testing was finding in cannabis, it made me wonder what we would find if other agricultural products were subjected to the same level of scrutiny. It also raised an obvious question for me: why would we consider a certain level of pesticide residue unacceptable in a cannabis gummy but not ask the same question about that level of residue on something like a raspberry?
A cannabis farm does not exist in isolation
Pesticide drift is one of the problems cannabis farmers have to account for. The Environmental Protection Agency defines spray drift as pesticide dust or droplets moving through the air during or shortly after application to somewhere other than the intended target. A cultivator can control what is applied to their own plants. It is much harder to control what is happening on a neighboring property.
Cannabis is subject to contaminant standards that can be far more demanding than those applied to neighboring crops. So a pesticide can be used lawfully on one property and still cause the cannabis next door to fail.
Drift isn’t the only way contamination can reach a cannabis crop. Agricultural land has a history. Chemicals and heavy metals present in soil or water don’t necessarily disappear simply because a new farmer buys the property and decides to grow a different crop.
Cannabis makes this especially relevant because the plant is known to take up certain contaminants from soil and has been studied for its potential use in phytoremediation, the use of plants to extract or stabilize contaminants in the environment. That characteristic may be useful when the objective is environmental remediation. It is obviously less desirable when the plant is going to be processed into something people inhale or ingest.
At LEEF, we started doing our own analysis when material failed. We looked at where it came from, surrounding agricultural activity and what pesticides were being used nearby. That changed the way we thought about sourcing. You can be a responsible farmer and still have a contamination problem if you don’t control what is happening around you.
Why we went looking for land
Eventually, we realized that testing and careful sourcing could only take us so far. If clean biomass was going to remain non-negotiable for us, we needed more control over where and how that cannabis was grown. That search led us to Salisbury Canyon Ranch, a roughly 1,900-acre property in the Cuyama Valley of Santa Barbara County.
The ranch is extremely remote. Cell service disappears well before you arrive and there is very little around you. For what we were trying to accomplish, that isolation was one of the property’s biggest advantages. The ranch is surrounded largely by mountains and natural terrain, away from the dense conventional agricultural activity found in many farming regions of California.
Before committing to the property, we went beyond simply taking soil samples. We collected native plants growing on the property, processed them through small-scale extractions in essentially the same way we would process cannabis and then tested the resulting material for pesticides.
We wanted to understand the land as thoroughly as we could and make sure it gave us the foundation to grow clean cannabis at scale. That was a major reason we chose Salisbury Canyon Ranch. Owning the cultivation gave us much more control over the environment and the process from the beginning.
What cannabis can tell us about agriculture
Our experience at LEEF has made me think a lot more about agriculture generally. Genetically engineered crops now account for more than 90 percent of the acreage devoted to several major U.S. crops, including corn and soybeans, with herbicide tolerance among the dominant traits.
These technologies give farmers effective tools for controlling weeds and producing crops at scale. But I think we should keep asking questions about the long-term consequences of agricultural systems built around widespread chemical use.
Parkinson’s disease is particularly personal to me. The federally supported Agricultural Health Study and research using California pesticide-use records have reported associations between exposure to certain pesticides and Parkinson’s disease.
None of that tells me what caused Parkinson’s in my mother, grandfather or friend. At the same time, I don’t think uncertainty should stop us from asking questions about long-term environmental exposure, particularly when the consequences can take decades to understand.
Our industry has spent years testing at a level that most agricultural products are not subjected to. As a result, we have learned a lot about what can end up in a plant and how contaminants move through the supply chain.
Cannabis has shown us what becomes visible when you actually look this closely. After years of working under these standards, I think we have learned things about testing and contamination that could be useful well beyond cannabis.
Where we go from here
I support the direction of California’s new contaminant standards. If we know a contaminant presents a legitimate risk and laboratories can reliably test for it, the industry should figure out how to meet that standard. Consumers should be able to expect that products sold in the regulated market have been tested for contaminants that could affect their health.
The system around those standards also needs to work. Operators need enough notice to adapt, laboratories need to produce consistent results, and when a product fails, we should try to understand why. Was something improperly applied? Did it come from a neighboring farm, the soil or water? Understanding what happened can help prevent it from happening again. I also think better testing standards will eventually be needed at the federal level so everyone is being measured with the same measuring stick.
As cannabis gets bigger, there will be pressure to make production cheaper and easier. I don’t want that to come at the expense of the standards the industry has spent years learning how to meet.
There are plenty of areas where I think cannabis needs less regulation. This isn’t one of them. We can improve how the rules are written and implemented without lowering the expectation that cannabis should be clean. I think the rest of agriculture should be moving closer to those standards, not the other way around.
Twenty years ago, getting sick after spraying Avid changed the way I grew cannabis. Since then, I’ve spent years seeing what increasingly sophisticated testing can find and how difficult it can be to keep contaminants out of the agricultural supply chain.
To me, that is ultimately the case for clean cannabis. We now have better tools than ever to understand what ends up in the plants we grow and the products we consume. Cannabis has shown us what we can learn when we actually use those tools. We should keep those standards high in cannabis and start expecting more from the rest of agriculture.
Micah Anderson is CEO of LEEF Brands, a California cannabis extraction and manufacturing company.
Disclosure: LEEF Brands is a sponsor of Cannabis Confidential. Todd Harrison, who publishes the newsletter, told High Times that as of publication, CB1 Capital holds no position in LEEF and does not advise the company.
Editor’s note: The views expressed are those of the author and do not necessarily reflect the views of High Times. This article has been edited for clarity and length.
