Denver recently conducted random tests of more than two dozen local dispensaries to learn more about potential yeast and mold issues with marijuana, and the results weren’t good.

On August 19, the City of Denver sent a notice to every licensed marijuana dispensary in the city, warning that investigators would be conducting random assessments at about 25 stores in the coming weeks “to evaluate contaminants in products on store shelves.”

“Each sample will be tested for pesticides and total yeast and mold by a state- and ISO-certified marijuana testing facility. Results of their respective testing will be shared with each facility and will also be shared broadly within a write-up of results,” the announcement read.

Although that write-up is still months away from being released, Westword learned of the tests and analyzed 25 Denver Department of Public Health and Environment dispensary inspection reports filed over a two-day span in September. Of the reports filed between September 9 and September 11, twenty listed at least one or more hold and quarantine orders for cannabis flower, shake or pre-rolled joints, an 80 percent failure rate. Each of those disciplinary actions was tied to plant matter testing above the maximum allowed for total yeast and mold.

The failed plant matter wasn’t typically covered in white and gray mold like an old piece of bread, but can still carry potentially toxic fungi that isn’t detectable by the naked eye.

DDPHE officials would not confirm whether all 25 of the tests conducted within that two-day period were part of the planned assessment of potential mold and yeast issues, though they acknowledge that some were.