By Veronica Morgan

Colorado has legalized recreational pot use, but is it safe? An investigation carried out by the Denver Post, had more than 1000 marijuana samples from two shops tested. Despite a statewide ban on pesticides instituted more than 6 months ago, the samples revealed some growers are still using them.

Peter Perrone, center, is the lab director at Gobi Analytical, the only lab in Denver that tests marijuana for pesticides.  (Photo By Mahala Gaylord/The Denver Post)

Samples were taken to Gobi Analytical labs, the only state sanctioned laboratory for testing marijuana. Peter Perrone is the lab director who revealed the results of his study. Perrone explains, “Pesticides do not dissipate on indoor grows, like they do on plants grown outdoors.” He also explained that pesticides should not be applied in either case once the plant begins to bud. Even if this advice is followed, indoor plants will still have minute traces.

All of the samples tested showed trace amounts of pesticides. Most of these traces were well below the acceptable levels allowed by the Colorado Agricultural Department, and were pesticides that were approved for use.

The part per billion was so low that it was hard to label. Perrone did say these levels were safe for casual users, but those who smoke more, increase their risks.

Some of the samples showed dangerous levels of the chemicals, myclobutanil, imidacloprid and avermectin- all of which have been banned by the state. The levels of toxic pesticides were six times the maximum of those allowed for any food item.

Lozenges and edibles had the highest concentration of pesticides.

Earlier this year, authorities quarantined 100,000 plants, grown using dangerous pesticides. The result was that several chemicals were banned, statewide. The Denver Post investigation exposed two tests that showed concentrated marijuana products that contained unacceptable levels of the banned pesticides.

All the tainted products came from Mahatma Concentrates in Denver, which made its extracts from raw marijuana grown by Treatments Unlimited, which operates the Altitude shops in Denver. The co-owner of Treatments Unlimited, Chase Bradshaw, admitted they had used products that contained the banned pesticides.

“We used to use Eagle 20 (myclobutanil); I will not deny that…However, we were never a business that would use it in an illegal manner or preventative manner. It was always as needed, maybe once every three months or once every six months, once a year, but never as a part of a regimen,” Bradshaw said. He also claims they have stopped using the product. None of the Mahatma’s labels listed the chemicals, although required by law.

Mahatma co-founder, Brett Mouser, asserted, “Mahatma doesn’t use any banned pesticides. We buy trim on the secondary market, and that trim is what we make our wholesale concentrates out of.” When asked about the labeling issue, Mouser blamed a former employee of “an unfortunate labeling mistake.” He says he has no idea how many of his products were labeled improperly.

Danica Lee, food-safety section manager in the public health inspections division of Denver’s Department of Environmental Health says, “These products contain high levels of residues from multiple pesticides, which poses a potential health risk to consumers. The Department of Environmental Health will begin an investigation immediately.”

All marijuana businesses are supposed to test their products, but since Gobi is the only lab certified to test marijuana the system has broken down. The law was implemented in 2013, but has not been enforced.

Plants grown indoors retain more of the pesticides than those grown outdoors.

Ian Barringer, founder of Rm3 Labs in Boulder, explains that since marijuana is still illegal under federal law, there have been no restrictions made regarding the use of pesticides.

“The most pressing potential health risk in this industry is likely to be pesticides. There has not been any clear health impact to date, but certainly, there are concerns about the cumulative impact of smoking potentially pesticide-laden marijuana.”Barringer went on to say, “And since there is effectively so little regulation of what pesticides are being applied and in what quantities, there is ultimately the potential for long-term risk.”