Colorado issues safety warning over strains of potentially moldy medical and recreational marijuana

Beware moldy weed: Colorado issues safety warning over six strains of marijuana that may be contaminated with spores, yeast or bacteria

  • An advisory was issued last week that 6 strains of potentially contaminated medical and recreational marijuana may have been distributed 
  • A technical error by a third-party tracking company incorrectly marked some batches as safe
  • Dispensary shelves carried the products between October 21 and November 14
  • No one has reported any illnesses from using the affected cannabis 

Colorado officials have issued a warning that several strains of potentially moldy and contaminated marijuana may have been distributed to six dispensaries.

The possible contamination affects both medical and retail marijuana, according to an advisory jointly released last week by the Colorado Department of Revenue and the Colorado Department of Public Health and Environment.

Six strains accidentally made it onto dispensary shelves between October 21 and November 14 due to a ‘technical error’.

The warning was made ‘due to the identification of potentially unsafe levels of microbial contamination’ although no specific microbials were mentioned.

No one has reported falling ill yet from smoking or consuming the potentially contaminated marijuana.

A advisory in Colorado was issued last week that six strains of potentially contaminated and moldy marijuana was marked as safe and placed on dispensary shelves between October 21 and November 14

Cannabis can be contaminated with heavy metals, pesticides, and other chemicals while the plant is being grown and harvested.

If the plant is stored in humid conditions, fungal mold and bacteria such as E. coli and salmonella can fester and grow.

If someone smokes, eats, or vapes contaminated marijuana, the spores or bacteria can travel to the lungs, resulting in life-threatening illnesses. 

Medical and recreational marijuana in Colorado are tested by Metrc, a third-party tracking system, which is meant to analyze whether each batch as acceptable or unacceptable levels of microbials. 

The company says a technical error occurred between October 21 and November 13 because of a software update.

As a result, some batches were given an incorrect testing status and were sent out despite being potentially contaminated.

Metrc told CNN that no other states were affected by the technical error and it was corrected on November 14.

‘We strongly encourage licensees to continue the best practice of checking test results in addition to the status presented in the system,’ David Urbanowicz, Metrc’s director of external affairs & business development, told the news channel in a statement.  

The affected medical marijuana strains include 9LB Hammer, Blue Dream and Super Lemon, which were sold at the dispensaries Cross Genetics, Elevations and Tweedleaf, the release said.

Retail strains believed to be contaminated include Ghost Cake Killah, Grape Ape, and Snowball, which were sold at Doctors Garden and Green Dragon, Mighty Tree and Natural Alternatives for Health.

Customers who purchased the products are urged to either discard the product or return them to where they were purchased.

The Colorado Department of Revenue Marijuana Enforcement Division did not immediately respond to’s request for comment.