Category 4 Testing for Cannabis: A Conversation with Alec Dixon

Alec Dixon: I’m one of the Co-Founders of SC Labs, and my role is centered around client relations, technical services, and business development. SC Labs has been testing cannabis since 2010, and we’re committed to ensuring the safety and quality of this plant by providing comprehensive data on both its phytochemical content and any potential contaminants. Our goal is to empower those we work with to make data-driven decisions to ensure safe and high-quality products for consumers.

AD: Category 4 testing, often called “Cat 4,” is an emerging standard in the cannabis industry. It goes beyond the state’s compliance testing by including additional pesticide screenings that aren’t on the state-required lists, such as the notorious “LA Times Nine.” This expanded testing is a response to the broken system of oversight in certain regions, where highly contaminated products are making their way to shelves alongside cleaner-than-food-quality products.

The LA Times article earlier this year highlighted how some products on dispensary shelves were contaminated with pesticides and other harmful substances, while others were exceptionally clean. It exposed a significant dichotomy that ultimately compromises consumer trust. Cat 4 testing is the industry’s way of addressing this and ensuring that products are truly safe and free from harmful contaminants.

AD: The turning point came after the LA Times expose, which revealed alarming levels of pesticides in cannabis products that weren’t being caught by California’s current compliance tests. Dispensaries, particularly progressive ones like Catalyst (who sparked this movement,) as well as Embarc, Mercy Wellness, and CBCB are part of a growing coalition of retailers who are taking it upon themselves to clean up their shelves and ensure that their consumers are only getting the highest-quality products. These retailers are leading the movement by requiring brands to go beyond just the state-mandated testing. Category 4 testing checks for these additional pesticides, such as pymetrozine, a chemical that’s been found in concerning quantities and is known to be harmful.

AD: Brands benefit from being transparent about the quality of their products. In an industry where clean, pesticide-free ingredients are scarce, brands that adopt Cat 4 testing are able to differentiate themselves. This new standard helps them demonstrate to consumers that they are serious about safety and quality.

Also, there’s a growing demand from retailers who are refusing to stock anything less than Cat 4-clean products. Being able to provide that assurance opens doors to better shelf space and consumer trust. For brands, it’s not just about passing the tests—it’s about taking ownership of their supply chain and ensuring their products are safe from seed to sale.

AD: Certainly. One of the most striking examples is pymetrozine, a chemical often used to treat aphids in nurseries. It’s not on the official California compliance list, so many cultivators didn’t realize it was harmful. However, pymetrozine is found in extremely high concentrations in some cannabis products, especially in extracts and distillates. Brands that don’t screen for these additional chemicals are inadvertently passing contaminated products onto consumers.

Retailers like Catalyst are stepping up by incentivizing clean products, which is driving brands to adopt Cat 4 testing voluntarily. We’re seeing an industry-wide shift, where retailers are creating supply chains that prioritize Cat 4-clean materials, pushing everyone from cultivators to extractors to ensure their products meet higher standards.