A study conducted by National Jewish Health found that police can be exposed to dangerous levels of mold during illegal, indoor marijuana-growing busts.
The researchers worked in tandem with and was funded in part by the Colorado Drug Investigator's Association (CDIA), County Sheriffs of Colorado and the Colorado Association of Chiefs of Police after law enforcement groups began expressing their concerns about the respiratory hazards of busting indoor marijuana gardens.
The CDIA expressed their concerns in part on their website:
In order to prevent detection, MGO's (marijuana grow operations) are frequently established in a house or a portion of a house that can be easily confined. Since a residential structure is not designed to function as a greenhouse, contamination by pesticides and fertilizers is more difficult to control, moisture can cause damage to building materials and result in excessive mold growth, and the risk of fire is significantly increased.
The study's lead researcher, Dr. John W. Martyny, said that he and his team had conducted a similar report in early 2000 on meth labs.
In this study, titled "Health Effects Associated with Indoor Marijuana Grow Operations," 30 marijuana growing operations were sampled in and around Denver that had been identified by law enforcement and compared mold spores and carbon dioxide levels with the outside air.
According to the study, marijuana grow operations have incentives to keep carbon dioxide levels higher than levels that can be found outside because it is "very important in determining the THC content of plants." Though the study acknowledged that these elevated carbon dioxide levels are not a public health concern, it warned that the levels are high enough to potentially cause some health problems.
The study also pointed out that elevated mold spore levels appeared most often when the number of plants exceeded 50, with instances of Penicillium mold species, which can cause infections.
Westword's William Breathes, the publication's anonymous medical marijuana reviewer, however, largely dismissed the study, writing:
The pictures they showed of carpeted grow rooms, where some plants lacked drain pans and electrical cables ran through murky, half-filled ones, and vent caps were removed from hot water heaters to increase Co2 in the basement, were startling. Stuff like this is horrifying to anyone who knows what a clean, nicely run grow operation can look like.
And that is the one thing the study completely neglects to acknowledge: Clean home grows or legitimate medical marijuana grow facilities can be just as well-maintained as any other legal, commercial growing facility or home-hobby grow. Indeed, the data hints at that being the case. Note one grow with eleven plants, at which both the average and the range of mold spores inside were considerably less than outside.
Dr. Martyny ultimately recommended that cops wear respirators and other protective gear as a precaution when entering illegal marijuana grow ops.