Are You Smoking Pesticides With Your Pot?

New study finds pesticides on marijuana plants can transfer to inhaled smoke.

Photo Credit: Shutterstock.com/ Igor Kolos

When you smoke pot, you might also be smoking a glut of nasty chemicals. A new study published in the Journal of Toxicology found that up to 70 percent of the pesticides on a given marijuana bud can transfer to the inhaled smoke.

Researcher Jeffrey Raber, a chemist who runs a medical cannabis testing company in Pasadena, Calif. called the Werc Shop, conducted the study inspired by prior research conducted on cigarettes, which showed that smokers could inhale compounds present on tobacco. 

Raber presented his findings at a talk titled, “Medical Cannabis Quality Control in California: Keeping a Weed Free Garden,”at Humboldt State University in November as part of a lecture series put on by Humboldt Institute for Interdisciplinary Marijuana Research. The talk focused in part on the contaminants found in cannabis smoke, as well as a number of other topics, which an article in Eureka’s Times-Standard categorized as “everything from erroneous branding at dispensaries and testing procedures to the various components of marijuana and the ways to determine the best strains to treat specific ailments.”


Raber’s lecture ultimately left a message of caution for the marijuana buyer.  

"Because this is currently quasi legal if not illegal in some places, and people are motivated to be making a commercial amount of money in a small amount of space, with no regulations and no quality control, anything that can be brought out to the market will go out to the market,” Raber said.

Raber noted that within California any use of pesticides on cannabis plants is illegal. However, as cannabis cultivation also remains illegal on the federal level, as well as in California state aside from specified medical grows, there is no oversight in place to regulate what is sprayed on cannabis plants. Further, cannabis growers can’t legally apply to be certified organic when they aren’t using pesticides or other chemicals. Without independent laboratory testing like Raber’s, there is no way to tell whether or not a bud is covered in toxic chemicals.

According to Raber, about 10 percent of the marijuana tested in his lab registers positive for pesticides on average. All of those samples come from medical marijuana dispensaries as well as patients who have sought out testing.The Times-Standard reported that in one random study in Raber’s lab, more than 35 percent of marijuana failed pesticide tests.

Raber said in the talk that his studies point to a need for “serious regulations” within California to determine what can and can’t be sprayed on marijuana plants, “especially in the medical patient context.”

Research has already confirmed the devastating effects of pesticides on human health. Pesticide use is linked to sterility in humans as well as animals, cancer, and numerous additional chronic illnesses according to Radcliffe's Integrated Pest Management (IPM) World Textbook at the University of Minnesota. An IPM report titled "Public Health Risks Associated with Pesticides and Natural Toxins in Foods" states that human poisonings and their related illnesses "are clearly the highest price paid for pesticide use," and notes that about 67,000 pesticide poisonings are reported each year in the U.S.

Raber noted in his talk that when you inhale something “it’s much like injecting it straight into your bloodstream,” as the body has filters in place for things that are ingested, which don’t apply to things that are inhaled.

Raber’s lab tests for about 30 to 40 different types of chemicals, based on the U.S. Environmental Protection Agency’s intake limits. He noted that the list used is “certainly not perfect."

The Time-Standard spoke with Humboldt County Sheriff Mike Downey, who said his deputies have found “massive amounts" of "high-powered pesticides" at marijuana gardens in the county, including those with posted medical marijuana recommendations.

Downey told the Times-Standard he'd like to see some studies specifically looking at the cumulative impacts of inhaling these substances over the course of years, or even decades.

AlterNet ran a related article in October titled “The New Reefer Madness: Drug War Crusaders Blame Pot Growers for Dead Animals, But the Drug War's to Blame,” which notes that Downey is among a series of unlikely advocates of national marijuana legalization, as a means of amping up regulation.

The article discussed the decimation of rodent populations due to the use of rodenticides in the many illegal or “trespass” cannabis grow sites, which are hidden deep inside Humboldt County forests. Rodenticides are deadly to wildlife as well as the hawks and owls that naturally prey on rodents. While the media and some authorities point to the trend as a reason to bolster the war on drugs, the article notes legalization would better fix the problem because those grows would no longer be forced to operate undercover.

“Amplified by a willing national media, the environmental harms caused by pot have become the new 'reefer madness,’ … [b]ut some Northern California officials who are on the frontlines of combating trespass grows say they're only a symptom of a much larger problem: the drug war itself."

Butte County Supervisor Bill Connelly, a conservative who describes himself as "definitely not an environmentalist," said in the article that “ramping up the war on pot because of trespass grows will ultimately fail to either eradicate the farms or protect Mother Nature. As a result, he's joined advocates like Downey in calling for the legalization of marijuana nationwide."

The same idea holds true in the case of pesticide use. If marijuana were legalized, pesticide use could be regulated and overseen, and organic growers could delineate their crops as such. As cultivation remains unregulated, it remains a potential health threat. 

Jeffrey Raber says while his study is the first of its kind and turned out some alarming results, more detailed studies are needed.

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April M. Short is a freelance writer who focuses on health, wellness and social justice. She previously worked as AlterNet's drugs and health editor.