Last verified: March 2026

Every cannabis product sold at a licensed Michigan dispensary must pass laboratory testing before it reaches the shelf. This testing is mandated by the CRA under administrative rules R 420.1 through R 420.1004 and is performed by licensed Safety Compliance Facilities. But Michigan's testing system faced a devastating credibility crisis in 2024–2025 that exposed systemic fraud, triggered the largest cannabis recall in state history, and prompted legislative action to overhaul how testing is supervised.

The Viridis Laboratories Scandal

The Viridis Laboratories scandal is the most consequential testing failure in any U.S. cannabis market to date. Understanding what happened is essential context for any Michigan cannabis consumer.

Background

Viridis Laboratories was founded by three former Michigan State Police forensic employees who leveraged their law enforcement credentials to build a cannabis testing company. At its peak, Viridis controlled approximately 60% of all cannabis testing in Michigan, making it the dominant lab in the state by a wide margin.

The Accusations

Investigations by the CRA revealed a pattern of serious misconduct at Viridis, including:

• Inflating THC potency results: Viridis was accused of systematically reporting higher THC percentages than products actually contained, making products appear more potent than they were. This practice attracted business from growers and processors who wanted high THC numbers for marketing purposes.
• Using unapproved testing methods: The lab allegedly used analytical methods that had not been validated or approved by the CRA, undermining the scientific reliability of their results.
• Misidentifying visible mold: Perhaps most alarmingly, Viridis was accused of failing to identify — or actively concealing — visible mold contamination on cannabis products. Mold can pose serious health risks, particularly for immunocompromised medical patients.

The Recall

The Viridis investigation triggered the largest cannabis recall in Michigan history, with approximately $229 million worth of products recalled from more than 400 dispensaries statewide. Products that had passed through Viridis testing were pulled from shelves and quarantined as the CRA worked to determine which results could be trusted and which could not.

Enforcement Actions

In August 2025, the CRA took its most severe enforcement action against Viridis: all three founders were permanently banned from Michigan's cannabis industry. This lifetime ban prohibits them from holding any cannabis license, working for any licensee, or having any ownership interest in a cannabis business in Michigan.

Prism Triangle

The testing integrity crisis extended beyond Viridis. Prism Triangle, another Michigan testing laboratory, was accused of manipulating pesticide calibrations — the reference standards used to determine whether pesticide levels in cannabis products exceed safe limits. Manipulating calibrations could cause contaminated products to appear clean, allowing pesticide-laden cannabis to reach consumers.

Together, the Viridis and Prism Triangle cases demonstrated that Michigan's system of relying entirely on private, for-profit testing laboratories had systemic vulnerabilities. When labs compete for business from cultivators and processors, there is an inherent financial incentive to produce favorable results — a conflict of interest that the existing regulatory structure did not adequately address.

HB 4501: The State Reference Lab Proposal

In direct response to the Viridis scandal and broader testing integrity concerns, Michigan legislators introduced HB 4501, which would authorize the creation of a state-run marijuana reference testing laboratory. This reference lab would serve as an independent auditor of private testing facilities.

Key elements of the HB 4501 proposal include:

• Audit authority: The state reference lab would have the power to re-test samples that have already been analyzed by private labs, checking for accuracy and consistency
• Method validation: The lab would establish and validate standardized testing methods that private labs must follow
• Proficiency testing: Regular proficiency tests would be sent to private labs to verify their results are accurate
• Independent oversight: Because the reference lab would be state-operated, it would have no financial relationship with cultivators, processors, or private labs

HB 4501 represents a significant shift in Michigan's approach to cannabis testing oversight. Rather than relying solely on private labs to self-regulate, the state would maintain an independent capability to verify and audit testing results.

Required Testing Categories

Despite the integrity issues with specific labs, Michigan's underlying testing requirements remain comprehensive. All cannabis products must be tested across these categories before they can be approved for sale:

Potency Analysis

Labs measure the concentration of major cannabinoids, including THC, THCA, CBD, and CBDA. For flower, potency is reported as a percentage by weight. For edibles and tinctures, potency is reported in milligrams per serving and per package. Accurate potency testing is essential for consumer dosing — especially for edibles, where overconsumption is the most common adverse event for new users.

Pesticide Screening

Cannabis must be tested for a panel of prohibited pesticides. Because cannabis is inhaled or ingested, pesticide residues can pose direct health risks. Labs screen for dozens of specific pesticide compounds and any product that exceeds acceptable limits fails testing and cannot be sold.

Heavy Metals Testing

Cannabis plants can absorb heavy metals from soil and water. Labs screen for four primary heavy metals:

• Lead — A neurotoxin with no safe level of exposure
• Arsenic — Associated with long-term health risks including cancer
• Cadmium — Particularly dangerous when inhaled
• Mercury — A potent neurotoxin

Products that exceed established limits for any of these metals are rejected.

Microbial Testing

Products are screened for harmful microorganisms including mold, yeast, E. coli, and Salmonella. Microbial contamination is a particular concern for immunocompromised patients, including many medical cannabis users. The Viridis scandal's mold misidentification allegations made this category especially significant in Michigan.

Residual Solvents

Concentrates and extracts made using chemical solvents (butane, propane, ethanol, CO2) must be tested to ensure that solvent residues have been properly removed during manufacturing. Inhaling residual solvents can cause respiratory irritation and other health effects.

Mycotoxin Screening

Mycotoxins are toxic compounds produced by certain types of mold. Even when mold is not visually present, mycotoxin contamination can occur during cultivation or storage. Labs test for specific mycotoxins including aflatoxins and ochratoxin A.

Moisture Content and Water Activity

Flower products are tested for moisture content and water activity to ensure they are within acceptable ranges. Excessive moisture promotes mold growth, while insufficient moisture degrades product quality.

The Testing Process

Cannabis testing in Michigan follows a structured workflow tracked through the Metrc seed-to-sale system:

1. Sample collection: A representative sample is taken from each production batch
2. Metrc tracking: Samples are tagged and tracked through Michigan's Metrc seed-to-sale system from collection to results
3. Laboratory analysis: A licensed Safety Compliance Facility performs all required tests using validated analytical methods
4. Certificate of Analysis (COA): The lab issues a COA documenting all test results for the batch
5. Pass/fail determination: Products that meet all CRA standards are approved for sale; products that fail any test category are quarantined
6. Retail release: Only products with passing COAs can be transferred to dispensaries and sold to consumers

Understanding Certificates of Analysis

A Certificate of Analysis (COA) is the official lab report for a specific batch of cannabis. When reviewing a COA, look for:

• Cannabinoid profile: THC, THCA, CBD, CBDA, and total cannabinoid percentages or milligrams
• Terpene profile: Individual terpene concentrations (when tested)
• Contaminant results: Pass/fail status for pesticides, heavy metals, microbials, mycotoxins, and solvents
• Lab identity and license: Confirm the testing was performed by a CRA-licensed Safety Compliance Facility
• Date of testing: When the analysis was performed
• Batch/lot number: Should match the number on your product's label and the Metrc tag

Looking Forward

Michigan's cannabis testing infrastructure is at a turning point. The Viridis and Prism Triangle scandals exposed serious flaws in a system that relied on self-regulating private labs. The industry and regulators are now working to rebuild consumer trust through multiple mechanisms:

• HB 4501 and the proposed state reference lab would add an independent layer of oversight
• Permanent bans on bad actors signal the CRA's willingness to impose severe consequences
• Metrc tracking provides the infrastructure for rapid recalls when problems are identified
• Consumer awareness — understanding the testing system's history helps you make more informed choices about which brands and products to trust

All marijuana products must be tested by a Safety Compliance Facility licensed by the CRA for potency, pesticides, heavy metals, microbial contaminants, residual solvents, mycotoxins, and moisture content before they can be approved for retail sale.

Michigan Cannabis Regulatory Agency