PROVIDENCE, R.I. (WPRI) — Nine medical marijuana businesses have had batches of cannabis test positive for banned pesticides since testing was mandated earlier this year, according to state regulators.

The Department of Business Regulation says none of the products ended up being sold to patients, and all the batches that failed pesticide testing have either been destroyed or quarantined pending a re-test.

Rhode Island only started enforcing pesticide testing on June 30 of this year, despite medical marijuana being sold in the state since 2013.

Medical marijuana patients for years expressed frustration about the delay in implementing mandatory testing in Rhode Island, which finally began last year with testing for potency. Other mandatory tests check for heavy metals, molds and other contaminants.

There are 17 pesticides banned by the Department of Health, and products are considered positive if they are found to have more than 10 parts per billion in a lab test.

“It’s particularly acute as a problem here in the cannabis context because in large measure these are products being lit on fire and inhaled,” said Matt Santacroce, the chief cannabis regulator at DBR.

All three of the state’s original medical marijuana dispensaries are among those whose products have tested positive since June 30, according to the DBR: Thomas C. Slater Compassion Center in Providence, Rise Dispensary in Warwick (formerly known as Summit Compassion Center), and Greenleaf Compassion Center in Portsmouth.

All three dispensaries purchase cannabis from other dispensaries in addition to growing their own.

“The failures that have occurred at the compassion centers have occurred on the production side of the house,” Santacroce said. “They have not made it to the retail side of the house.”

At the Slater Center, 13 batches of concentrate tested positive for banned pesticides in October, according to the DBR. State regulators went to the facility to watch the products be destroyed on Oct. 11.

In a corrective action plan, Slater says they don’t use the banned pesticides, and note that 11 out of the 13 batches contained cannabis they bought from outside cultivators.

“Because [Slater] does not use prohibited pesticides, it cannot with certainty identify the source for the positive laboratory tests,” Raymond White, the chief operating officer at Slater, wrote in the corrective action plan. “The imposition of mandatory pesticide testing has revealed that some licensed cultivators have not followed the prohibition on pesticide use.”

The plan says Slater will take a number of actions including pre-testing products before they get to the mandatory testing stage.

“In the hundreds of batch tests conducted on our oil, a small number showed the presence of prohibited pesticides,” spokesperson Chris Reilly said. “The batches were held in quarantine and never made into any products sold to patients. The batches were destroyed in compliance with state regulation.”

“No products were ever available for sale from any of these batches, and no patient was ever sold anything from the positive lab tests,” Reilly continued.

Dr. Seth Bock from Greenleaf Compassion Center similarly blamed outside cultivators for bringing the pesticides into the medical dispensary.

“None of Greenleaf’s in-house product line tested positive for pesticides as Greenleaf does not use anything but organic pest remediation methods per the state regulations,” said Dr. Seth Bock, CEO of Greenleaf. “What you are referring to are third-party products produced by state licensed cultivators and purchased by Greenleaf that did not pass the testing standards. Greenleaf identified this issue and none of these products we ever sold at Greenleaf.”

Rise dispensary in Warwick did not return a phone call seeking comment. That business did destroy its products that tested positive, according to the DBR.

Santacroce said the DBR has no evidence of any business directly spraying banned pesticides on their plants. The products could have become contaminated with pesticides through someone’s clothing, or even through the HVAC from pesticides that were sprayed outside.

For example, two of the six cultivators that tested positive told Target 12 they sprayed for bugs outside their facilities, and their indoor products later tested positive for those pesticides.

“We had a really bad ant problem,” said Mike Cirillo of RI Tree Service in West Warwick. “We never sprayed anything on the plants.”

Despite spraying for ants outside, the products from the indoor cannabis grow tested positive for the banned pesticide in September. Cirillo said the company got rid of all the ant sprays, and is now looking for an organic way to get rid of ants outside.

“It’s nice to know that they’ve implemented all this high-quality testing for patients,” Cirillo said.

The other cultivators that tested positive for banned pesticides were Nova Farms in Central Falls, Cann Cure in Warwick, Jardins Garden in Warwick, STJ in Warwick and RI Cultivation in Cranston.

Blair Fish, the chief operating officer at Nova Farms, says the company purchased an existing marijuana cultivation this year that was in use before the pesticide testing went into effect, and also has other cultivation facilities in the building.

“At no time has Nova Farms RI ever used the pesticide that was discovered in the testing,” Fish said.

He said the business voluntarily tested a batch from before the June 30 mandatory testing date, which tested positive. The batch was destroyed, and the business was sanitized and is fixing a leak in the roof that could have been a source of cross-contamination.

“We will not commence cultivation operations again until we are positive there is no longer any potential cross contamination,” Fish said.

Chris Jardin from Jardins Garden, who said his indoor products tested positive after he used a small amount of insect spray outside to contain a beetle infestation, questioned whether the state’s pesticide threshold is too low.

“The 10 parts per billion is way too low,” Jardin said, adding that one of his tests came back detecting 10.1 parts per billion. “It’s nonsensical.” He noted that other states have higher thresholds for certain pesticides.

Jardin said his staff spent weeks sanitizing the facility, and he is sending baby plants out for further testing.

Rhode Island has “some of the strictest tolerance limits for pesticide residues in cannabis across the country,” according to Dr. Jason Iannuccilli of PureVita Labs, which tests Rhode Island cannabis for pesticides.

Iannuccilli said there’s not enough data to determine the most appropriate threshold for the pesticides deemed harmful by federal regulators, which may have resulted in states setting their thresholds “excessively low.”

“There’s simply no ‘rule book’ to follow for cannabis right now,” Iannuccilli said. “Allowable federal limits for pesticide residues in our food supply, for example, do not translate directly to cannabis products that are smoked, since the level of absorption into the bloodstream are different through the gut than through the lungs.”

A spokesperson for the R.I. Department of Health confirmed they have received a request from cannabis business owners to raise the threshold for banned pesticides.

“They asked that the current regulations be reviewed and come into alignment with other states,” said Annemarie Beardsworth, a spokesperson for the DOH. “This feedback is being taken under advisement. Any changes or revisions to Rhode Island’s regulations would happen through the required public process.”

In the meantime, Rhode Island is gearing up for recreational marijuana sales starting on Dec. 1, which initially will take place at the existing medical dispensaries, using the existing marijuana cultivators.

Santacroce said the same testing standards will be used for non-medicinal cannabis, and said the recent positive tests for pesticides show that the procedures work.

“We’re happy with the way the system is working,” Santacroce said. “We’re happy that zero products that have failed the enforced pesticide test have made it to a retail location or to a patient.”

Steph Machado ( is a Target 12 investigative reporter covering Providence, politics and more for 12 News. Connect with her on Twitter and on Facebook.