Cannabis testing regulations: A state-by-state guide

Published on February 24, 2020 · Last updated January 23, 2024
cannabis potency testing, marijuana testing
(AP Photo/Jeff Chiu)

This guide was updated on Feb. 24, 2020.

In most legal states, cannabis products that you purchase from a licensed facility are required to undergo a series of tests by a state-accredited lab. These tests help ensure that products are safe to consume and accurately labeled. Lab tests primarily screen for potency and levels of THC and CBD, residual pesticides, unwanted contaminants, and the presence of mycotoxins like mold and mildew. But as with everything in the cannabis world, requirements can vary widely state to state.

The importance of required lab testing was borne out during the 2019 VAPI lung injury outbreak. Vitamin E oil, the culprit in the outbreak, wasn’t specifically tested for by most cannabis labs—at least not initially. But because most states required lab-verified data on the potency of vape cartridge oil, the number of carts cut with vitamin E oil that were sold in licensed, regulated stores and dispensaries remained near zero.

If you value your health, insist on lab-verified product safety and potency. If your state doesn’t require it, contact your state legislator and demand it.


Cannabis is not legal in Alabama. So: No testing.

For now, the only legal option involves “Carly’s Law,” which allows select patients to legally possess and use CBD oil via permission from officials at the Department of Neurology at the University of Alabama-Birmingham. There is no provision for testing in Carly’s Law.


Like many states, Alaska’s marijuana testing system has been plagued by inconsistent test results from one lab to the next, resulting in ongoing doubt about the accuracy of what’s on the label of a given product.

The lack of lab accountability led to lab-shopping by cannabis growers, who would go lab-to-lab looking for the highest THC or lowest contaminant content. That left consumers with little confidence in the percentages on a given label.

Alaska Marijuana Control Board officials updated testing regulations in 2019, in part to tighten those loopholes. The new rules call for random and supplemental sampling for testing at the Board’s discretion, and expands the list of contaminants each batch must be tested for, including some pesticides and heavy metals. (Those updated rules can be found here; scroll down to Article 6.)

As of early 2020, certified labs in Alaska are testing for cannabinoid potency (including THC, THCA, CBD, CBDA and CBN), microbial contamination, residual solvents, and heavy metals.

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Arizona’s robust medical marijuana industry has been operating for years without any required testing. That’s scheduled to change on Nov. 1, 2020, when all dispensaries will be required to test their products.

Starting on that date, products will be tested for microbial contamination, heavy metals, pesticides, herbicides, fungicides, growth regulators, and residual solvents. Cannabis products will also be tested to determine cannabinoid potency. The Arizona Department of Health Services will license third-party labs to carry out the tests.

In 2019 Arizona lawmakers moved to make medical cannabis more widely available and, along the way, made the long-overdue move to certify testing of those products. That means that as of September 2019, Arizona’s handful of established testing labs were brought under state control. Before then, those labs operated without regulation, meaning that while they were allowed to operate, the quality of what they produced didn’t adhere to any enforceable standard for potency or safety. That move, under SB 1494, closes a loophole in a state law that was passed in 2010.


Arkansas adopted cannabis testing standards in May 2017, a year after lawmakers legalized the sale and possession of medical marijuana. But it was only in March 2019 that the first testing lab, operated by Steep Hill, opened for business, and it wasn’t till May 2019 that medical marijuana was actually cleared for sale.

By state law, labs are largely self-policing but follow established ISO standards for testing, including for pesticides, solvents, moisture content, microbial contaminants and heavy metals, among other elements from every “lot.” Any medical cannabis product that doesn’t pass testing or meet state standards must be sterilized or destroyed.

Of special note in the specifics of the state law is a proviso that medical marijuana labeling in Arkansas not “be attractive to minors,” though, unfortunately, that isn’t further defined.


Testing in the Golden State is stabilizing after a rocky start, which included a number of recalls of products falsely and deliberately cleared by testing labs but later found to be contaminated. The state now requires all cannabis to be tested for cannabinoids, terpene content, mycotoxins and heavy metals in addition to moisture content, residual solvents, pesticides and microbial impurities. In late 2019, many labs took it upon themselves to test for Vitamin E acetate, the primary culprit in the VAPI lung outbreak, and the state skated up to the brink of issuing a heavy-handed ban on vape products before opting for an educational approach to vaping contaminants.

California’s testing regulations: All in one chart. (Courtesy of California Bureau of Cannabis Control)


As in California, Colorado began requiring cannabis cultivators in 2018 to submit their flower and trim batches—recreational as well as medical—for testing for mycotoxins, heavy metals and other pesticides, following some recalls. That’s on top of the many other contaminants and conditions that are already tested for under state law. And as in California, growers are complaining about the $100-per-strain cost. They’re saying that as a result, they may have to offer fewer strains for testing and thus for sale.

The state appears to be doubling down on testing: On Aug. 15, 2019, the Marijuana Enforcement Division added concentrates to the list of cannabis products in Colorado that must undergo testing for mycotoxins. And in response to concerns about vaping-related sicknesses, the state Marijuana Enforcement Division has banned, effective Jan. 1, 2020, vitamin E Acetate, polyethylene glycol (PEG) and medium chain triglycerides (MCT oil) for use in the manufacture of regulated marijuana concentrate or regulated marijuana products intended for inhalation. Read more about that here.

Here’s the full list of what Colorado tests for, and a comprehensive look at how the state regulates the testing process.


Connecticut’s medical cannabis testing regulations are similar to those of other states—they call for self-policed testing for virtually all the same contaminants, including mycotoxins, heavy metals and pesticide residue.

State law also requires each medical marijuana brand label to display lab test potency results, including a terpene and cannabinoid profile including THC, THCA, CBD, CBDA, and any other active ingredient that constitutes at least 1% of the marijuana batch used in the product.


Delaware’s medical marijuana system is notoriously one of the nation’s least considered, and that includes its testing regulations.

State law forbids all use of pesticides in product grown and sold at “compassion centers,” as the state government refers to medical dispensaries. Compassion centers are also required by law to operate as non-profit organizations.

Interestingly, “pesticides” is the only category of contaminant specified in the law, which goes on to single out organochlorides, organophosphates, cargamates, and insectidal, fungicidal, or growth regulatory compounds. There’s no requirement to test for the presence of heavy metals.

Regulations also require the compassion center to include the name of the cannabis strain, cannabinoid profile, and quantity of the medical marijuana dispensed.

District of Columbia

Washington, DC, legalized medical marijuana in 1998 and the adult use of cannabis in 2014. Due to Congressional meddling, however, the first medical dispensaries didn’t open until 2013. There are no licensed and operating adult-use cannabis stores—again, due to members of Congress objecting to the idea.

The District’s medical cannabis must go through a rigorous set of tests that look for: moisture content, water activity, terpene and cannabinoid levels (THC, THCA, CBD, CBDA, CBN), foreign matter contamination, microbial and/or mycotoxin contamination, heavy metals (arsenic, cadmium, lead, mercury), pesticide and/or fertilizer residue, residual solvents, and homogeneity (for edibles).


Florida has operational third-party cannabis testing labs, and many producers and dispensaries use those labs—but at this point testing for toxins and contaminants in medical marijuana products remains entirely voluntary. There are no state regulations requiring specific tests.

In late 2018, it was reported that “aside from some regulations on potency, there are no specific guidelines.” Senate Bill 8A, which governs medical marijuana testing in Florida, said nothing about specific contaminants; it said only that tested marijuana “should be safe for human consumption and free from human contaminants.” It further required the state Department of Agriculture and Consumer Services to set maximum allowable levels for contaminants. That has yet to happen.

Senate Bill 182, which allowed the sale and use of smokeable cannabis flower, took effect on March 18, 2019—but it contained no further guidelines about what exactly the state’s cannabis testing labs should test for.

Later law enforcement guidelines issued by the state in April 2019 made no mention of specific contaminants or their allowable maximum levels; they seem more concerned with security, chain of custody and keeping products away from children. The only requirement is that products display their lab-verified THC and CBD levels.

In 2019 the Gainesville Sun reported that some cannabis producers were lab shopping, going door-to-door with contaminated product to different testing operations until they obtained “clean” results. “It’s the wild west out there right now,” said one lab operator.

The top-level takeaway for medical marijuana patients is this: Buyer beware. Ask a lot of questions at your dispensary. Demand to see test results from the batch you may be purchasing. And tell your state lawmaker it’s unacceptable for medical patients to ingest untested and potentially contaminated medicine.


It’s been legal to possess CBD oil in Georgia since 2015, and it’s the only form of cannabis that won’t land you in jail. In March 2019 the Republican-controlled state legislature passed a bill allowing the sale of “low THC” CBD oil. Low THC is defined in Georgia as a product containing no more than 5% THC. Products will be available only in liquid form, and the use of non-organic pesticides will not be allowed in the production of raw cannabis.

The new Georgia Access to Medical Cannabis Commission will establish testing regulations, but the Commission just had its first meeting in Dec. 2019, so it may be a while before any rules are enforced.


Medical cannabis has been legal here since 2016, but the industry got off to slow start because testing labs didn’t open until the summer of 2018, roughly in tandem with the state’s first authorized growing operation.

By state law, testing is done for pesticides (even though Hawaii’s agricultural practitioners largely shun them), as well as for heavy metals, solvents, moisture content, microbial contaminants, intestinal bacteria and pathogens, “dangerous molds that can cause infection and disease,” and “toxins produced by molds.”

The state’s labs set a tough standard early. Steep Hill, which runs two of the Aloha State’s four labs, rejected 20% to 30% of the batches it tested in late 2018, largely because of the presence of bacteria, mold, yeast and other biological contaminants.


All forms of cannabis are illegal in Idaho, but advocates are working to put a medical legalization initiative on the statewide ballot in Nov. 2020.


Medical cannabis dispensaries have been operating statewide since 2015, and the state’s first adult-use cannabis shops opened on Jan. 1, 2020.

The list of contaminants that must be tested for under state law includes “pesticide chemical residue” and “residue solvent” alongside microbiological contaminants, mycotoxins, with no mention of heavy metals.


All forms of cannabis except hemp are illegal in Kentucky.


For years, Maine was one of many states that outlawed pesticides and contaminants in its medical cannabis but did not mandate testing of those products.

That changed in Sept. 2019, when Maine lawmakers drafted and passed emergency legislation setting specific but self-policed standards and testing protocols for medical marijuana, which include limits on heavy metals. That was done partially in response to a rash of complaints about sicknesses suffered by medical marijuana patients. Testing of products used by those folks found harmful solvents like naphtha, used in paint thinner, and rubbing alcohol, as well as an array of pesticides, molds and harmful bacteria.


In the aftermath of the nationwide VAPI outbreak in 2019, Maryland lawmakers expanded the state’s testing requirements to include the presence of toxic levels of heavy metals in medical cannabis. That means testing must now be done at both the growing (flower) and processing (oil) stages. Lawmakers call the move—which is required for vaping products only—a correction to an oversight in the original medical marijuana law.

Lead is the culprit du jour, but chromium, manganese and nickel have also been identified as problem contaminants. State law covering all medical marijuana products—not just vape carts—also calls for product batches to be tested for hair, insects, molds and microbiological impurities.


As with most parts of its cannabis regulatory scheme, Massachusetts’ Cannabis Control Commission sets a high national standard in the way the state operates. Laws regarding marijuana can be found here; specific thresholds for contaminants can be found here.

First: No pesticides of any kind are allowed—even including organic pesticides. None. Nada.

Second: Massachusetts ties specific tests to specific product types, a specificity rarely seen in any legal state. Here’s an illustration of products and tests:

Massachusetts: Testing protocols for various products

“MIPs” stands for Marijuana Infused Products. (Table: Massachusetts Cannabis Control Commission)


Michigan sets clear standards for cannabis testing. After years of confusion and delay, the state’s new comprehensive cannabis bureau, the Marijuana Regulatory Agency, seems to be acting clearly and decisively when it comes to keeping products clean and consumers safe.

In Nov. 2019, as other states reacted to the VAPI crisis with knee-jerk vape bans, Michigan’s MRA adopted one of the nation’s smartest rules. The agency banned the use of vitamin E oil, and limited all future vape additives to substances that have received FDA approval as an inhalant. (Vitamin E oil had famously been FDA-approved as a skin care topical, but not as an inhalant.) The MRA also announced twice-monthly inspections of processing facilities to ensure compliance with those standards.

As of early 2020, Michigan regulations required testing for cannabinoid and terpene potency, foreign matter, microbial and mycotoxin contamination, pesticide and chemical residue, fungicides, and the presence of residual solvents.


Minnesota established vague testing standards for medical cannabis but has left the implementation of those standards to the labs it certifies. The “analytes” that the labs must test for in each batch include pesticide residues and plant growth regulators, heavy metals, mycotoxins, micobiological contaminants and residual solvents.

In response to concerns about the safety of vape products available to medical-cannabis patients, Minnesota’s sanctioned MMJ manufacturers say their products are safe, that they don’t use Vitamin E acetate and other highlighted contaminants in their production. But, they added, they would conduct additional testing to “further validate our formulas.” So far, they’re self-policing; the state is not mandating new testing standards. But that hasn’t stopped Minnesota Gov. Tim Walz from seeking a statewide ban on vape-cart sales.


All forms of marijuana are illegal in Mississippi.


Medical cannabis was approved here in 2018, and dispensaries are expected to open in mid-2020. As of early 2020, explicit standards for testing medical marijuana products are still in development.


The state is in the process of overhauling its standards to give the state Board of Health more direct oversight over medical-cannabis testing, which is currently handled by sanctioned labs under highly detailed state regulations. Medical marijuana in the Big Sky State has been in near-constant flux since it was approved in 2004. For the time being, third-party lab testing targets the usual contaminant suspects and then some under fairly standard quality controls, including “mammalian excreta.”


All forms of marijuana are illegal in Nebraska.


Labs here test for some two dozen contaminants, but some say the list isn’t long enough, and want the state to address the need to limit the presence of chromium, nickel and other metals associated with stainless steel, which is associated with vape carts. Right now, under state law, third-party labs test only for arsenic, lead, cadmium and mercury under the “heavy metals” label (here’s the complete list).

Meanwhile, in shades of Casino, Nevada regulators in 2019 started investigating labs for possible manipulation of test results by “criminal influences,” in the words of Gov. Steve Sisolak. The move is in response to complaints about excessive levels of yeast and mold in MMJ flower and pre-rolled products. That investigation began in September 2019; no results have been reported yet.

New Hampshire

Testing regulations for the state’s “Therapeutic Cannabis Program” and its “Alternative Treatment Centers” (i.e., dispensaries) have remained largely unchanged since medical marijuana was made legal in 2014.

Interestingly, “metals” are not specified on the list of contaminants that each batch must be tested for. New Hampshire is one of the few states that omits it. That could have interesting effects on vape-cart sales there, as the state saw a rush of out-of-state customers when neighboring Massachusetts imposed a four-month ban on such sales in September 2019, and even after the moratorium was modified in November to exclude medical marijuana.

New Jersey

The state’s testing regulations for medical cannabis have been more of a constant than the law itself, which limited the availability of such products to the point of strangulation until July 2019, when Gov. Phil Murphy put his pen to a law that finally expanded and overhauled the Garden State’s medical marijuana program. With the bigger program comes a bureaucracy to manage it—the Cannabis Regulatory Commission—and presumably, more up-to-date testing regs than those established by the state Department of Public Health Services in 2011.

New Mexico

The state has had a stable and comparatively comprehensive set of testing regulations, including testing for heavy metals in vape carts, since medical cannabis was approved there in 2015. There have been some modest updates as recently as October 2019.

What New Mexico tests for and why

New York

The state has an expansive list of contaminants that its approved third-party labs must test for—including some that no other state tests for, like salmonella and E. coli. (See page 69 of this document for the full list.)

New York officials point to the comprehensiveness of their medical marijuana program’s testing criteria in talking about the recent VAPI outbreak, pointing out that none of the reported illnesses were linked to state-authorized providers.

North Carolina

Marijuana is not legal in North Carolina.

North Dakota

The state’s first “compassion centers,” as they’re called there, opened in March 2019, more than two years after voters approved medical cannabis in 2016, and six are set to be opened by the end of 2019. Difficulties in establishing a regulatory structure accounted for the delay, and the first of two testing labs in North Dakota didn’t open until April 2019.

Labs test for the usual list of substances—pesticide residue, microbial contaminants, solvents, heavy metals, etc. The full list can be found here at page 28. Labs are subject to demands for random testing from the North Dakota Department of Health at any time—at their expense.


Ohio’s medical marijuana program was approved by legislators in 2016 but didn’t launch until early 2019, has struggled amid complaints about limited eligibility, high prices and low accessibility (almost all the dispensaries are in the eastern half of the state). Some of those complaints have centered on testing regulations that are said to be more restrictive than those of many other states.

The program has further suffered from a November 2019 recall of three different medical marijuana products that made it to shelves but were found to have flunked lab testing for microbial contaminants. And they’ve labored to let patients know that the vape products they’ve approved for sale are safe in the face of the street-cart health scare.

Here’s what Ohio labs test for; here are the rules under which they’re allowed to operate.


Since medical legalization became official in June 2018, more than 200,000 patients, or nearly 5 percent of the state’s population, have signed up for the program. That’s more than twice what state officials expected when they set up the Oklahoma Medical Marijuana Authority (OMMA).

Result: The initial lack of state-mandated testing regulations left the quality control over medical marijuana products in the hands of private testing labs, each of which operates by its own standards. But an August 2019 change in the law mandated that OMMA must approve all new testing labs, but so far there are no such labs—just the ones that have been doing business all along. That’s not likely to change soon, as the state application process for labs opened Nov. 1, 2019.

And that’s led to fears that mold, metals, pesticides or other contaminants could sneak into medical marijuana products for sale throughout Oklahoma that may not have been subjected to testing as rigorous as other labs might provide. Here are the rules for testing medical marijuana in Oklahoma.


Oregon’s medical marijuana program is, to many who have worked within it, “confusing, messy, underfunded and poorly regulated.” That’s a common byproduct of states with separate bureaucracies for medical and recreational-use cannabis that were never meant to coexist. As recreational-use cannabis has become more popular and less expensive than its medical equivalent, the supporting infrastructure around medical marijuana has become starved of customers and cash, and diminished.

That may have played a role in the summer 2019 death of a man from a tainted vaping product reportedly sold by an Oregon dispensary. That came at a time when the Oregon Cannabis Commission, an advisory board, did recommend that OMMP needed better cannabis testing to ensure tainted medical marijuana products from hitting the market. Which may have led in turn to Gov. Kate Brown’s attempt to ban all nicotine and THC-based vaping products for sale in October 2019, further starving the medical market, though courts have since blocked that move.

Here’s how Oregon’s marijuana lab testing works (for both medical and recreational products) and what it tests for—a list that excludes heavy metals and microbiological contaminants, among others.

Oregon cannabis testing: An overview


Medical cannabis, legal in Pennsylvania since April 2016, is, per one media report, “a victim of its own success.” The state has some 60 dispensaries and 200,000 registered patients. Demand has outpaced supply to such a degree that many patients haven’t been able to get what they need. That’s because the number of growers hasn’t risen proportionately, due to licensing hangups and other growing pains.

What does this say about the state of lab testing in Pennsylvania? Wild swings in humidity around the state make the presence of mold a constant challenge, some growers say, but, by law, there are no statistics available on how much prospective product has been screened out—or what might have slipped through.

Click here to read how Pennsylvania conducts its testing, and what it tests for.

Pennsylvania medical marijuana: Testing at a glance

Rhode Island

Rhode Island remains one of the few states that requires no testing of medical marijuana.

The state’s medical-cannabis program, established in 2006, is thriving, thanks to a number of factors: lack of legal recreational cannabis; a broad spectrum of qualifying conditions that make it easy to become an MMJ patient; a steady parade of out-of-state buyers from more restrictive states; and, reportedly, the willingness of many doctors to prescribe with few questions asked. The demand is so robust that it outpaces supply, leading to long waits at the state’s few licensed dispensaries and plenty of pressure to open more.

Unfortunately, quality assurance is something patients have to take entirely on faith.

That’s led to complaints and even protests from patients who fear the products on which they depend could make them sicker. Said one such patient, who ditched his Rhode Island medical card for a Massachusetts one, at a June 2019 protest rally: “The cannabis is not tested, not fully tested for heavy metals, pesticides, mold and such, and me being a cancer patient, I could die.” State officials say they’re working on it.

South Carolina

Cannabis remains illegal in South Carolina, and state authorities have gone so far as to raid stores selling CBD.

South Dakota

All forms of cannabis are illegal in South Dakota. Voter initiatives to establish a medical-cannabis program in South Dakota have failed repeatedly since 2006, but backers will take another run at it in 2020.


All forms of marijuana are illegal in Tennessee.


Texas allows patients to access only CBD oil with low levels of THC, and has no regulations regarding testing of those products.

The Lone Star State is a latecomer to medical cannabis, with the usual fits and starts seen in other states that don’t really want to deal with it. After initially approving an MMJ program in 2015 for those with intractable epilepsy, the Compassionate Use Program was expanded in June 2019 to encompass those suffering from a moderately broader range of seizure disorders. But the state shut down the application process for dispensaries in October 2019, shortly after opening it, without any explanation. Other bewildering developments have stymied the lab-testing industry in Texas for the time being as well; even law enforcement labs don’t know how to test the various forms of cannabis.


A medical-cannabis program, including mandatory product testing, was approved by voters in 2018. The state has announced it will issue 14 dispensary licenses to 10 companies, and start issuing patient registration cards not later than March 1, 2020. Once it gets up and running, Utah’s lab testing system may be one of the toughest and clearest in the nation. Those rules are spelled out in this July 2019 state bulletin.

Excerpt from Utah’s pesticide regulation rule


Vermont has no mandatory testing requirements for legal medical marijuana products sold within the state. Some dispensaries use their own in-house labs to test for potency and purity, but there’s no third-party assurance at this time. In 2016 the state legislature commissioned this report that spelled out in great detail how testing should be done, but it’s unclear why the information wasn’t acted upon.


Medical cannabis is coming to Virginia after the passage of bills in the state legislature in 2018 and 2019. There’s no specific date on when MMJ product will be sold, but the process of setting up a regulated supply chain, including establishing testing-lab regulations and certifications, is underway.


More than five years after the first adult-use cannabis stores opened in Washington, the state’s lab testing system remains broken. As Leafly’s Ben Adlin reported in 2019, the head of the state Liquor and Cannabis Board admitted, “We don’t have the expertise” to oversee a reasonable testing system—despite the fact that other legal states, apparently, do have that capacity.

Quoting from Adlin’s report:

Pesticides are perhaps the most obvious example. While state regulations prohibit the use of certain pesticides on cannabis, the LCB has never actually required that adult-use products be tested for those pesticides. Aside from the occasional surprise inspection, it’s entirely an honor system.

If that’s not a head-scratcher, consider heavy metals. The state spells out specific limits on individual metals, including arsenic, cadmium, lead, and mercury. Regulations say that products that exceed those limits “fail quality assurance testing.” But as with pesticides, the LCB doesn’t require that testing be done, except in the case of medical-only products.

“The testing program in Washington is weak,” said Aaron Riley, president of CannaSafe, a major California-based cannabis testing laboratory. “There’s really not safety requirements.”

Currently the state requires adult-use cannabis be tested for:

  • Potency, including THC and CBD levels
  • Microbial contamination, such as from mold, fungus, or bacteria
  • Mycotoxins, or toxic chemicals produced by microorganisms
  • Moisture, which can increase the risk of microorganism contamination

Why no provision for pesticides or heavy metals, even after five years of legal sales? Largely because of pushback by growers, who said the cost of product testing would be too big a burden, hurting small farms and driving up costs for consumers.

West Virginia

While the state’s medical cannabis program officially took legal effect in July 2019, state officials say that actual dispensary sales and product testing are two to three years away.


Marijuana remains illegal in all forms in Wisconsin. Backers of a medical-cannabis program here haven’t been able to overcome fears in the Republican-dominated legislature that legalizing medical use will necessarily lead to legalized recreational cannabis, but they’ll try again in 2020.


Marijuana remains illegal in all forms in Wyoming.

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Leafly Staff
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Leafly is the world’s largest cannabis information resource, empowering people in legal cannabis markets to learn about the right products for their lifestyle and wellness needs. Our team of cannabis professionals collectively share years of experience in all corners of the market, from growing and retail, to science and medicine, to data and technology.
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