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7 Oct 2022

Comparing Cannabis Lab Testing Regulations in Top U.S. Markets

Until recently—with the notable exception of Arizona—any cannabis product sold in a state-licensed retailer required testing by a third-party, state-accredited lab. Now that Arizona has enacted its cannabis testing regulations, the unanimity extends across all established and emerging markets. State agencies are trying to both ensure cannabis product safety and assure consumers that regulated products are a safer choice than purchasing through legacy pathways. While there are common elements to cannabis testing across states, comparing the details of each state’s ruleset reveals some perplexing disparities and shines a light on the need for a harmonized approach to testing.

Standard Cannabis Product Safety Testing

Mandates for product safety have evolved along with the rise of licensed markets for cannabis and hemp. The first thing consumers, manufacturers and regulators agree on: It’s important to know product potency, whether it’s flower, edibles, concentrates, vapes, tinctures or topicals. For example, in Michigan, licensed cannabis testing labs conduct mandatory potency testing for the following cannabinoids:

  • delta-9-tetrahydrocannabinol (∆9-THC) level

  • delta-9-tetrahydrocannabinol acid (THCA) level

  • delta-8-tetrahydrocannabinol (∆8-THC) level

  • Cannabidiol (CBD) and cannabidiol acid (CBDA) levels

  • Cannabinol (CBN) level

In addition to a potency analysis, cannabis labs typically conduct safety tests for the presence of foreign contaminants. For example, if cannabis is grown or processed in an environment that is not climate-controlled and kept clean, potentially harmful mycotoxins could be present. Testing can also detect levels of fungus, mold and mildew, and is critical to protecting consumer safety, particularly for those who are immunocompromised.

Testing for heavy metals is also a standard for most states because exposures to metals such as arsenic, mercury and lead can cause short- and long-term harm. This is of particular concern in cannabis because the cannabis plant is a phytoremediator, which means it absorbs through its roots and retains heavy metals and chemicals in plant tissues at a relatively high rate.

Certain pesticides are also potentially harmful to humans and animals. Products containing cannabis extract oils such as edibles, tinctures or vapes can be prone to elevated levels of pesticides and heavy metals depending on soil amendments, nutrients and pesticides added during the growing process that are then concentrated during processing.

Residual solvent analysis is another vital component of product safety testing for cannabis and hemp products. Biomass, aka plant matter, is extracted into a concentrated oil for use in edibles, concentrates, topicals and other products. This is commonly done by using solvents such as butane, propane, acetone and isopropanol, among others, to separate cannabinoids from the plant matter. This process can result in the presence of residual solvents (residual from the extraction process) making it important that manufacturers test their processing techniquest and ensure solvents are fully removed post-extraction.

Water activity, or the amount of available water in dried flower and infused products, is an important indicator of  susceptibility to spoilage and a product's appropriate shelf life. Microbial contamination that can occur in humid and unhygienic conditions could cause respiratory complications, allergic reactions or foodborne illnesses.

Differences in State Cannabis Lab Testing Regulations

While all licensed markets now have some type of formal testing program, those requirements can vary widely from state to state. This lack of uniformity across markets means that in some states there might be very basic standards, while others require extensive testing of a wide variety of compounds.

It’s important to note that cannabis testing labs themselves aren’t standardized at the federal or even state level. Some labs offer “opt-in” services that are not required by a certain state but are required in another. It’s possible that one lab conducts certain tests differently than another lab in the same state. Without federal legalization and oversight, numerous discrepancies in state testing requirements exist.

Other differences between state programs include the inability or willingness to conduct on-site inspections, mandatory microbial testing, various pesticide considerations and differences in action limits, which are threshold levels of any substance deemed a safety concern.

Outside of action limits, mediation rules also differ significantly. Some states do not allow remediation of products that failed testing, others allow it under specific guidelines and with requirements for transparency, and some allow remediation and do not have any parameters for how it must be done or what information is disclosed to consumers. That is the case in Michigan, which means it is possible for cannabis products that have been irradiated or treated with ozone to make their way to dispensary shelves without being labeled as such.

States also have differing requirements regarding production batch sizes and test samples. For example: How many individual servings of an infused edible constitute a sample? In Michigan, regulators prescribe standards for sampling, which PSI Labs utilizes to develop a Standard Operating Procedure (SOP) that is followed for all appointments.

Arizona is markedly different: Beyond a lack of sampling requirements, there is no state reference lab with compliance oversight of independent labs (this would be a state run laboratory that is capable of auditing laboratory data, testing samples that are part of an investigation and holding laboratories accountable to best practices ever evolving industry). In Colorado, although state regulators do not routinely collect cannabis samples to verify test results, it does occur relatively often when looking into complaints. The samples are then sent to the Colorado Department of Public Health and Environment's Cannabis Reference Lab for additional testing. In California, the Department of Cannabis Control inspects labs and runs its own laboratory that can process samples from any point in the supply chain. Arizona has no similar oversight infrastructure.

Here’s a closer look at testing regulations in California and Michigan, where PSI Labs operates state-licensed cannabis testing facilities, along with other top U.S. markets for comparison:

Cannabis Lab Testing Regulations in California

According to California’s Department of Cannabis Control (DCC), labs must test regulated cannabis products to make sure they are free of contaminants and labeled with accurate amounts of cannabinoids and terpenes. The testing scope includes:

  • Cannabinoid profile (potency)

  • Terpene content

  • Foreign matter

  • Moisture content and water activity

  • Microbial and mycotoxin contamination

  • Chemical residue analysis (pesticides, insecticides, fungicides)

  • Heavy metals

  • Residual solvents

In California, growers and manufacturers can remediate a product batch that fails testing, and the DCC must approve the remediation plan in advance. After remediation, the batch must be retested to ensure that the contaminant was removed. If the products pass the retest, they can be sold.

Cannabis Lab Testing Regulations in Michigan

Accredited labs in Michigan are required to test cannabis products for the following:

  • Potency Analysis

  • Delta-9-tetrahydrocannabinol (∆9-THC) level

  • Delta-9-tetrahydrocannabinol acid (THCA) level

  • Delta-8-tetrahydrocannabinol (∆8-THC) level

  • Cannabidiol (CBD) and cannabidiol acid (CBDA) levels

  • Cannabinol (CBN)

  • Terpene Analysis

  • Safety Concerns

  • Foreign matter inspection

  • Microbial panel (total yeast and mold, Shiga toxin-producing E. coli, salmonella, total coliforms)

  • Pesticides

  • Chemical residue

  • Fungicides

  • Insecticides

  • Metals screening

  • Residual solvents levels

  • Vitamin E acetate screening

For most of these categories, compliance testing can be split into two directives:

  1. Determining concentrations of the compounds that are considered positive and / or desired in the final product.

  2. Ensuring that any unwanted compounds do not exceed state-established safety limits.

If the cannabis sample in question does not meet state standards in any of the potential contaminants listed above, the producer that submitted the sample must either remediate and retest, or dispose of the entire batch and document disposal in Michigan’s cannabis tracking system.

Cannabis Lab Testing Regulations in Arizona

For years, Arizona was the only state that did not require any product testing for its medical cannabis program that launched in 2012. That was partially rectified in 2019 with the passage of SB 1494 which required that the Arizona Department of Health Services (ADHS) establish mandated cannabis testing through state-licensed testing laboratories.

But while growers and manufacturers must submit cannabis products to state-licensed labs for testing before products may be sold, the state currently lacks the infrastructure necessary to regulate the labs and ensure they are following the law.

Under Arizona’s lab testing regulations, Δ9-THC, THC-A, CBD-A and CBD are the cannabinoids that must be addressed. The following microbial contaminants and mycotoxins must be tested for as well:

  • Salmonella

  • Escherichia coli

  • Aspergillus flavus

  • Aspergillus fumigatus

  • Aspergillus niger

  • Aspergillus terreus

  • Aflatoxin B1, B2, G1, G2

  • Ochratoxin A

The heavy metals listed for Arizona are arsenic, cadmium, lead and mercury. There are 18 residual solvents and over 50 pesticides, fungicides and growth regulators that are also required for testing, along with a lone herbicide: pendimethalin.

Cannabis Lab Testing Regulations in Florida

Medical cannabis is legal in Florida and the state’s law requires a product Certificate of Analysis (COA) that shows a certified lab has tested for a lengthy list of compounds beyond a basic cannabinoid potency profile, including:

  • Microbiology

  • Residual solvents

  • Metals

  • Pesticides

  • Water activity

  • Moisture

  • Filth and foreign material

Florida describes contaminants unsafe for human consumption in cannabis as: “any microbial, fungus, yeast, mildew, herbicide, pesticide, fungicide, residual solvent, or metal found in an amount that exceeds any of the department’s accepted limitations or other limitation pursuant to Florida law, whichever is lowest.” Filth and foreign materials include “hair, insects, feces, packaging contaminants, manufacturing waste, and other similar marijuana cultivation and processing by-products.”

Cannabis Lab Testing Regulations in Illinois

Potency testing regulations in Illinois are not terribly specific. Packaging must show the following:

  • Delta-9-tetrahydrocannabinol (THC)

  • Tetrahydrocannabinolic acid (THCA)

  • Cannabidiol (CBD)

  • Cannabidiolic acid (CBDA)

The regulations mandate that all other ingredients, including additives for color, artificial flavors and preservatives, must be listed in descending order by predominance of weight shown with common or usual names.

Heavy metals that must be noted include lead, inorganic arsenic, mercury, cadmium and chromium. Other Illinois cannabis testing requirements include:

  • Microbiological contaminants

  • Mycotoxins

  • Pesticide active ingredients

  • Residual solvents

  • An active ingredient analysis

Per state regulations, if the sample failed the pesticide chemical residue test, the entire production batch must be disposed of properly. Notably, “if the sample failed any other test, the batch may be used to make a CO2- or solvent-based extract. After processing, the CO2 or solvent-based extract must still pass all required tests.”

Cannabis Lab Testing Regulations in Massachusetts

Massachusetts sets itself apart from other states by breaking down regulations based on product type. Finished plant products, cannabis resin, cannabis concentrates and infused products have differing action limits to pass. In most cases, a standard cannabinoid potency test is accompanied by heavy metal testing for arsenic, cadmium, lead and mercury. Labs must also test for nine pesticides.

Concentration limits for residual solvents are necessary for over 25 compounds as well as for levels of propane, n-Butane or isoButane.

Cannabis Lab Testing Regulations in New York

New York has an incredibly expansive list of contaminants that its approved third-party labs must test for, including salmonella and E. coli. Per regulations, testing cannabis products or medical cannabis “shall include, but not be limited to, microorganisms, foreign material, metals, moisture content and water activity, mycotoxins, pesticides, residual solvents, terpenoids, and any other analyte or group of analytes” determined by the State.

In terms of cannabinoids, the Empire State requires testing for:

  • Tetrahydrocannabinol (THC) as Total THC of: ∆9-THC; ∆8-THC; ∆10-THC;

  • Tetrahydrocannabinolic acid (THCA)

  • Tetrahydrocannabivarin (THCV)

  • Cannabidiol (CBD)

  • Cannabinadiolic acid (CBDA)

  • Cannabidivarin (CBDV)

  • Cannabinol (CBN)

  • Cannabigerol (CBG)

  • Cannabichromene (CBC)

Additionally, certain substances used in cultivation—including growth regulators—must be declared for targeted testing. Targeted testing will be supplemented by the testing of pesticide contaminants and their limits. Labs must test for over 60 different pesticides, such as myclobutanil and others.

Moisture content, filth and foreign material also make the list in New York. Hair, insects, manufacturing waste, animal feces and packaging contaminants are just some of the examples.

Last but not least, New York requires substantial testing for residual solvents. All solvents used during the production of adult use and medical cannabis products must be declared for targeted testing.

Cannabis Lab Testing Regulations in Washington State

Washington, which was one of the first states to legalize adult-use cannabis (2012), has robust testing standards with the exception of heavy metals. Licensed labs may gain certification for heavy metals testing, but it is not mandatory. However, labs must be certified to conduct the following tests:

  • Potency analysis

  • Foreign matter inspection

  • Microbiological screening

  • Mycotoxin screening

  • Pesticide screening

  • Residual solvent screening

  • Water activity

Since 2015, PSI Labs has operated with a relentless commitment to cannabis consumer safety and industry transparency. Contact us today to learn more about cannabis lab testing regulations and what they mean for your company.


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