Researchers Express Concerns Over Contaminated Marijuana Products

A recent journal article highlights concerns about contaminants in “medical” marijuana and other cannabis products.

Nationwide, many states have legalized marijuana to varying degrees, and the Trump Administration has moved to ease federal restrictions on the drug. But while policymakers push for more marijuana, scientific evidence shows there are serious health concerns surrounding marijuana.

Researchers writing in the journal Clinical Infectious Diseases say there are no standards for testing “medical” marijuana and other cannabis product for microbes and other contaminants.

The article says “microbial contamination” may happen “during cultivation, harvesting, processing, storage, and distribution, allowing potentially pathogenic organisms to persist in final consumer products.”

In other words, contaminants in marijuana may be harmful to the people who use it.

This is not the first time experts have warned about marijuana products being contaminated.

In 2024, lab testing from California found many marijuana products contained “concerning” levels of pesticides. Other research found marijuana often was contaminated with arsenic, lead, or mold, and that marijuana users may have higher levels of heavy metals in their blood.

Last year, the Oregon Liquor and Cannabis Commission tested 51 samples of industrial hemp flowers as part of the commission’s “Operation Clean Leaf” initiative. All 51 samples contained more THC than federal law allows, and authorities said some were tainted with dangerous pesticides.

Marijuana products are easily contaminated by pesticides and mold spores, because the marijuana plant itself easily absorbs toxins in the soil as well as chemicals or other substances sprayed on the plant.

These contaminants are passed along in marijuana products — posing serious health risks for marijuana users.

There are other concerns about marijuana besides the dangers from mold, pesticides, and other contaminants.

THC — the main psychoactive substance in marijuana — has been tied to everything from heart disease and cancer to stroke, mental illness, and even birth defects.

In fact, researchers now say marijuana use doubles a person’s risk of death from heart disease. That ought to give everyone pause.

All of this underscores what we have said for years: Marijuana may be many things, but “harmless” simply is not one of them.

Articles appearing on this website are written with the aid of Family Council’s researchers and writers.