As marijuana legalization spreads across states like Colorado, ensuring the safety of cannabis products presents a significant challenge due to a lack of long-term data on risks associated with pesticides and contaminants. Jeff Raber, CEO of The Werc Shop and cannabis educator at the University of Denver, emphasizes that safety varies from person to person, influenced by factors such as individual tolerance and consumption habits.
When Colorado legalized marijuana more than ten years ago, regulators had to rely on limited existing information regarding the potential risks posed by various substances found in cannabis products. Colorado mandates that growers test their crops for various contaminants, including yeast, mold, E. coli, pesticides, and heavy metals like lead. Additionally, manufacturers must check for residual solvents from the production process.
Raber notes that the science surrounding pesticide safety in marijuana is still developing. Existing tobacco regulations do not apply directly, as cannabis growers often use different pesticides. While Colorado has updated its pesticide standards to align with Canadian regulations, many questions remain about what levels of these chemicals are safe for consumption.
A 2013 study co-authored by Raber found that significant amounts of pesticides could pass through smoking devices, although the study did not account for newer regulations that may have lowered current risks. Current research primarily focuses on how cannabis affects users, rather than determining the safety of specific chemicals in smokeable products.
Research limitations are compounded by federal restrictions on cannabis cultivation for study purposes, although Colorado scientists are investigating pesticide residues and heavy metal contamination.
Mark Lefsrud, a medical cannabis researcher at McGill University, points out that not all contaminants in cannabis pose an inhalation risk. For instance, heavy metals found in edibles present more concern than when smoked, as inhalation does not easily convert these metals into harmful particles. Similarly, E. coli bacteria typically do not survive the high temperatures of smoking, and Colorado has not reported any recalls due to bacterial contamination since 2020.
However, mold poses a more considerable threat. Individuals with compromised immune systems or lung conditions are especially vulnerable to inhaling mold spores. Colorado allows growers to sanitize products to eliminate excess mold, but this process does not remove toxins that mold may have produced before treatment. Raber warns that unseen contaminants often present the greatest danger.
The Colorado Marijuana Enforcement Division requires testing of batches that fail mold tests if growers wish to remediate them for other uses, such as concentrates. Yet, the division has not issued recalls or taken action against businesses for toxin-related failures.
Regulations vary between states regarding permissible contaminant levels. Generally, states have adopted cautious approaches in setting these standards, often making decisions based on incomplete data.
Raber notes that while states can quickly respond to short-term health issues arising from contaminated batches, tracking the long-term effects of cannabis use remains challenging. Consumers often use various products, complicating the attribution of health outcomes to specific contaminants.
As an industry professional, Raber does not discourage adult use but emphasizes the importance of consumer awareness regarding safety uncertainties. He suggests varying product choices to minimize exposure to specific contaminants and moderating consumption as practical strategies for consumers.
Ultimately, ongoing research and improved data collection will be essential for addressing the safety of marijuana products and ensuring consumer protection as the industry continues to evolve.
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