Mold, pesticides and heavy metals can contaminate pot products, threatening to sicken users
Marijuana contaminated with arsenic, lead or mold is causing serious, even life-threatening illnesses around the country as use of cannabis products explodes.
People who have used marijuana have higher levels of heavy metals in their blood and are more likely to develop fungal infections, according to studies. Researchers have linked contaminants found in marijuana to cases of sudden-onset numbness, fatal lung bleeding and artery disease that resulted in amputations.
Last year federal health authorities received thousands of reports of poisonings and other harmful side effects that involved marijuana use, while an Arizona dispensary issued a voluntary recall of cannabis products sold as “Grim Reefer” for possible contamination with a sometimes lethal fungus called Aspergillus.
Contamination is a particular concern for marijuana products because the plant is a bioaccumulator. That means it absorbs heavy metals in the soil and compounds such as pesticides sprayed on the plant, as well as fungal spores, including mold, that might be spread by air and water, especially during harvesting.
The cannabis plant is so successful at cleaning tainted soil that hemp was planted around the site of the Chernobyl nuclear disaster site.
Anne Hassel quit consuming marijuana because of the contaminant risk.
Anne Hassel said her feet went numb, her muscles twitched and she developed nausea and cramps several years ago, after using marijuana and working in a dispensary. Doctors eventually found she had high levels of lead, cadmium and nickel, she said.
“People consider that if it’s legal, it’s safe. It’s a complete fallacy,” said Hassel, 56, a physical therapist in Chicopee, Mass. She quit consuming marijuana because of the contaminant risk.
Marijuana use has jumped in the U.S.—and stores selling pot and edibles have proliferated—since 24 states legalized recreational marijuana and 38 approved the drug’s medicinal use.
‘Buyer Beware’
Yet regulation of the quality and safety of the products hasn’t been able to keep up. Federal regulators set product standards for cigarettes and minimum standards for growing and harvesting fruits and vegetables on farms. But there aren’t any national standards for testing marijuana for possible contaminants such as pesticides, solvents, fungi and bacteria. Nor is there a federal agency providing oversight.
State and local regulation, meantime, is a patchwork. Some states like California require producers to test for dozens of contaminants, while other jurisdictions don’t require any testing at all.
“It’s buyer beware,” said Kevin Sabet, a former White House Office of National Drug Control Policy adviser during the Clinton, Obama and George W. Bush administrations. “You don’t know what you’re getting.”
Growers say they are committed to selling safe products, and many would welcome federal standardized testing. Some express concern that increasing regulation could raise their costs and drive consumers to the black market, where no testing requirements exist.
“They say pregnant women shouldn’t be smoking. They don’t ban cigarettes,” said Myron Chadowitz, a marijuana farmer in Veneta, Ore.
He opposed his state’s zero-tolerance requirement for certain types of Aspergillus mold, saying the mandate was too stringent and illnesses were rare. Yet he supports warning labels for people who are immunocompromised about the dangers of smoking marijuana.
Some doctors, scientists and health authorities have begun ringing alarm bells about the health risks from tainted marijuana. Studies have found cannabis users were 3½ times more likely to develop a fungal infection than individuals who didn’t use the drug and had higher levels of lead and cadmium in their blood and urine.