Myron Chadowitz and his cousin run a small family-owned cannabis farm in Eugene, Cannassentials. Unlike indoor cannabis grows, which use small individual pots for each plant, they said part of their secret sauce is growing cannabis in living garden beds that connect down to the native soil, utilizing natural elements of the ecosystem like flowers, wood chips, cover crop, worms, rolly pollies, and garter snakes.

But new rules from the Oregon Health Authority took effect in March 2023, mandating cannabis be tested for a microscopic mold called aspergillus. Chadowitz said this rule is forcing many farmers to use fungicides and radiation on their cannabis.

Seri Robinson, an associate professor of wood anatomy at Oregon State University, said there is a vast misunderstanding about this invisible mold. “Aspergillus is in the air all the time. So, at a standard airborne spur load, most people don’t even know it’s there,” Robinson said.

The Center for Disease Control said aspergillus is very common both indoors and outdoors, so most people breathe in fungal spores every day. For people with healthy immune systems, breathing in aspergillus is not harmful. But for people with weakened immune systems, breathing in aspergillus spores can cause an infection in the lungs or sinuses, which can spread to other parts of the body.