Auditors: 74% of Colorado Cannabis Product Batches Went Untested for Pesticides

On Monday, Oct. 19, at a Legislative Audit Committee hearing in Denver, state Sen. Rod Pelton listened to an auditor explain how marijuana gets tested in the first state to sell it to adults, and then asked a plain question. Pelton, a Republican from Cheyenne Wells, sits on the committee. Colorado lets the businesses being tested choose the samples that go to the lab. Was anybody going to fix that? (S1, S3, S4)

"If I'm a shady character, I know which products I'm going to sample and which ones I'm not," Pelton told the Legislative Audit Committee, according to Colorado Newsline's account of the hearing. "That's a pretty gray area to me." (S3, S4)

The answer came from Kyle Lambert, deputy director of the Marijuana Enforcement Division, the agency inside the Department of Revenue that licenses and polices the state's cannabis businesses. The division had studied ending self-selected sampling, he said, and had decided against proposing it this year. Reaching rural businesses would be a logistical and cost problem, and having a third party collect samples would not guarantee that a sample represented a whole batch. (S3, S7)

That exchange is a small piece of a long document. The Office of the State Auditor's performance audit, titled Marijuana Consumer Safety and dated Sept. 23, makes 14 recommendations to the enforcement division and the Colorado Department of Public Health and Environment. Both agencies agreed with all 14. The auditors said they found no evidence of widespread health and safety problems with regulated marijuana. They also found a testing regime riddled with exemptions, inspections that often run years apart, video evidence that is legally erased after 30 days, and a public-warning system so slow that potentially contaminated products stayed on sale for an average of 223 days before the state told consumers. (S1, S2)

For an industry whose central promise to customers is that a licensed product has been tested, the audit lands at an awkward moment. Last month a Pueblo County manufacturer doing business as Craft recalled vape cartridges after a private Denver lab found methylene chloride, a paint-stripping solvent. As of Oct. 9, the health department had logged 38 reports of adverse effects tied to the recalled products, a department spokeswoman, Gabi Johnston, told Westword. That case falls outside the audit, which reviewed 2023 through 2025, but it tests the same machinery the auditors examined. (S6)

The audit's sharpest numbers come from Metrc, the seed-to-sale tracking system every Colorado licensee uses. Auditors pulled the records for about 183,000 harvest batches and 310,000 production batches created from Jan. 1, 2023, through Dec. 31, 2025. Cultivators did not test about 68% of their harvest batches for pesticides. Manufacturers, who turn plant material into concentrates, edibles, pre-rolls and vapes, did not test about 74% of production batches for pesticides, 81% for residual solvents and 94% for mycotoxins. (S1)

None of that is necessarily illegal. State law directed the division to cut redundant testing, and its rules allow several exemptions, including for some concentrates and skin and body products. The largest is the Reduced Testing Allowance, a program that dates to 2014. Under rules adopted in 2024, a business can pay a fee, attest that it passed an initial run of tests, and then submit one batch for the relevant contaminant test every 30 days as long as those samples keep passing. The auditors found the division does not verify that a business meets the requirements before it begins using the reduced schedule, and does not track how many businesses rely on the general exemptions. The national regulators' group CANNRA told auditors that reduced-testing programs are generally not advisable without other controls, and the few states that run one pair it with tighter limits, ISO accreditation, third-party sampling or shelf testing. (S1)

Then there is the sampling itself. Colorado businesses select their own samples, on camera, and send them to private labs they pay. According to research by the division cited in the audit, 24 other states rely on lab staff or an independent third party to collect samples, while 15 others work roughly the way Colorado does. One division investigator told the auditors that because sampling runs on the honor system, licensees who want to subvert testing have the opportunity. (S1)

The safeguard meant to catch that is video. Businesses must record sample collection, but the rules require them to keep the footage for only 30 days. The division's own goal is to inspect each business every two years, and in practice it often misses that. Among businesses active for the entire three-year review, 93 cultivators, or 38%, and 97 manufacturers, or 52%, were inspected once or not at all. Auditors found other businesses that went as long as five years without an inspection. By the time an investigator arrives, the tape showing how the sample was chosen is usually long gone. (S1)

The second half of the audit is about speed. When the division finds a problem, its main public tool is a Health and Safety Advisory, posted online and emailed to subscribers. From 2023 through 2025, the auditors found, potentially harmful products were available to consumers for anywhere from a week to a little more than three years before an advisory went out. The average was 223 days, just under seven and a half months. In 2025, after the division rewrote its advisory guidelines, the average fell to 5.7 months. (S1)

For the 13 advisories from 2025 that they examined in detail, auditors traced each milestone. On average the division issued an advisory about three and a half months after opening an investigation, and about a month after the investigator decided one was needed, against an internal goal of 18 days. Seven of the 13 took longer than 90 days from investigation to advisory. In nine cases the division asked the business to issue a voluntary recall, which requires the least evidence, and some of those recalls did not stop the product from being sold. In one, the company had tracked its inventory so badly in Metrc that neither the recall nor a later embargo found all of it. In another, stores that had bought the product never answered the company or the investigator. (S1)

“As a result, there is an increased risk that marijuana products sold in Colorado may have contaminants or that the potency listed on the labels is inaccurate.”

— Office of the State Auditor, Marijuana Consumer Safety performance audit, 2553P

Part of the delay is structural. The state reference lab run by the health department cannot test for pesticides, so when investigators need a pesticide result they ask the business under investigation to collect a sample, watch it being sealed, and send it to a private lab. The division has been advised that, as a law enforcement agency, it can hand marijuana only to another government entity, so investigators cannot take possession of a product and send it to a private lab themselves. Health department officials told auditors that a lab able to do the work would cost just over $13 million, including about $7.2 million for new facilities. The audit asks lawmakers to consider strengthening the lab's role. (S1, S3)

Catherine Friday, the audit supervisor, summed it up for the committee. "It's really a combination of factors that impacts MED's ability to identify public safety risks and to ensure that businesses comply with safety requirements," she said, according to Colorado Newsline. (S3)

The division's leadership leaned hard on the line about no widespread problems. "We recognize there are clear opportunities to improve through the audit's recommendations, and we also appreciate the state auditor's acknowledgment that it found no evidence to support claims of widespread health and safety issues with regulated marijuana products," Dominique Mendiola, the division's senior director, said in a statement reported by Newsline. The division said it would assess the testing exemptions now allowed under state law and rules. (S3, S4, S7)

The division's own investigators are less sure. Auditors surveyed them, and of the 17 who answered, six said they believe product safety problems in the regulated market are widespread, four said they may be, and seven said they are not. Self-selected sampling and the reduced-testing program came up again and again in their comments. Most of those rules, the audit notes, predate the division's current leadership, and in the past the division has proposed tighter rules only to see the legislature walk them back. (S1)

There is a real cost argument on the other side. Lab tests in Colorado run from $235 to $525 per sample, according to the audit, and the exemptions exist because lawmakers told regulators to stop charging businesses for duplicate tests. Earlier this year the division floated requiring lab personnel to collect samples, then dropped the idea after manufacturers said it would raise their costs, ProPublica and The Denver Gazette reported. Lambert's point about rural logistics is a real one, and as he told the committee, an outsider taking a sample does not by itself make the sample representative. (S1, S3, S4)

1. 2027 legislative session: the Legislative Audit Committee can vote on whether to introduce a bill on the state reference lab's role, the audit's one legislative recommendation.
2. Ongoing: the Craft recall and the health department's count of adverse-effect reports, which stood at 38 on Oct. 9.
3. December 2027: the division's stated implementation date for Recommendation 1, which covers sampling, reduced testing, penalties and video retention.

Pelton did not get a commitment on Oct. 19. Lambert told him the division might still revisit the issue. Under the rules as they stand, a Colorado manufacturer can still pick the jar that goes to the lab, keep the video for a month, and, as auditors found for more than a third of cultivators, see an inspector once in three years or not at all. The audit's fix for that runs through Pelton's committee, and through the legislature that wrote most of those exemptions in the first place. (S1, S3, S4)

Keep Reading

Supply Chain

Comment window

DOCKET 7951 · RULEMAKING

Nebraska's First Legal Cannabis Crop Is Weeks From Harvest. No Lab Is Licensed to Test It.

All four licensed growers asked the Medical Cannabis Commission to defer $36,500 a year in proposed fees until a supply chain exists. The interim chair says they were warned to plan on storage. The commission takes up its rules on Nov. 16.

By Cannabis Inc, Editorial Staff·7 min read

Supply Chain

A Paint Stripper Turned Up in 49 Colorado Vapes. The Testing Rule That Would Have Caught It Was Due in July.

StayCon, doing business as Craft, pulled Maui Wowie and Grape Gorilla cartridges after a private Denver lab found methylene chloride. The Marijuana Enforcement Division has still not warned consumers, and says it does not comment on investigations.

By Cannabis Inc, Editorial Staff·7 min read