Politics
Cannabis Industry Should Develop More ‘Consistent’ Drying Methods, Federal Science Agency Says
A new report from a federal science agency examines moisture and drying standards in hemp, part of an ongoing project to help laboratories ensure accuracy and precision when testing cannabis products.
The National Institute of Standards and Technology (NIST) published the report late last month, finding considerable variation in moisture levels from facilities that used different approaches to drying. The agency said the results indicate “the need for consistent hemp drying method(s) for accurate and precise measurements.”
The 29-page paper is the latest in NIST’s so-called Cannabis Laboratory Quality Assurance Program (CannaQAP), launched in 2020. The program’s most recent prior report, published last year, focused on determining cannabinoid content in plant material samples, following earlier reports on moisture content and certain toxins and heavy metals.
The program, created after the 2018 Farm Bill’s federal legalization of hemp, is split into three exercises. The first centered on measuring the concentration of up to 17 different cannabinoids in hemp oil. NIST published a report on that segment in mid-2021.
Exercise 2, completed last year, looked at testing of dried cannabis plant samples rather than hemp oil. In addition to cannabinoid testing, it expanded the scope of the exercise to include testing for moisture content as well as 13 toxic elements.
The new paper is the first portion of Exercise 3 of CannaQAP. In addition to the latest report on moisture in cannabis, Exercise 3 will also include additional forthcoming reports on testing for cannabinoids and toxic elements.
A NIST representative told Marijuana Moment that the two final reports could be published by the end of the year, “but more likely sometime in 2026.”
Findings in the new report come from an exercise in which 89 participant laboratories were provided with a plant sample and asked to assess its moisture level.
Overall, just 20 percent of the participants reported moisture levels within NIST’s target range, the study says. On average, the mean moisture level was approximately 2 percent above the agency target.
The labs used a variety of analysis methods, the paper notes, but “the majority of laboratories with mean moisture values within the target range either used either [thermogravimetric analysis] or selected ‘other’ as their method option.”
“Other” was in fact the most common method listed by laboratories, with 29 saying they used an unlisted form of analysis. Thermogravimetric analysis was second most common, with 28 labs using the method.
“In general, systematic and/or random errors were the cause of the majority of inaccurate or less precise results,” authors wrote. “These errors are most likely the result of inappropriate sample storage and/or weighing inconsistencies.”
“A sample and crucible can take on moisture after leaving the oven, desiccator, or freeze dryer,” they noted. “It is essential to store the crucibles containing the samples in a desiccator after they are removed from the drying apparatus. It is equally important to start with a crucible that has been adequately dried and stored in a desiccator prior to use. The crucible and sample should be weighed when the sample and crucible are at ambient temperature. Otherwise, buoyancy errors will result in an incorrect final sample mass.”
Walter Brent Wilson, a research chemist at NIST who co-authored the new moisture report as well as past CannaQAP reports, explained the purpose of testing for cannabinoids, contaminants and moisture in comments to Marijuana Moment last year.
“Since cannabinoids are increasingly used in over-the-counter supplements, they were included again in this CannaQAP exercise for participants to continue to evaluate their in-house analytical methods in dried hemp plant materials,” he said. Accurate measurement of heavy metals and other toxic elements was crucial, he added, “since they are known environmental pollutants that can accumulate in cannabis and significant potential exists for human exposure to toxic elements following hemp consumption.”
As for moisture, that’s important largely because federal law measures cannabinoid content on a dry-weight basis, and, similarly, “many toxic element safety thresholds are on a dry mass basis,” Wilson said.
A separate NIST report last year found that many products being sold as hemp met the federal definition of marijuana, with the vast majority of smokable hemp product samples–about 93 percent—containing more than 0.3 percent THC.
Earlier this year, meanwhile, NIST had been planning an April event to convene government officials, forensics experts, academics, industry representatives, law enforcement and standards organizations for what it described as “an open and candid discussion” about “the path forward to realize meaningful cannabis breathalyzer technology and implementation.”
A month ahead of the event, however, a NIST official told Marijuana Moment that the workshop had been postponed. The cannabis breathalyzer event has now been rescheduled for September.
Topics to be discussed will include challenges facing marijuana breathalyzer design and development, obstacles to prosecutors handling drugged-driving cases and how NIST and other entities might partner to advance the technology.
As for other federal study into cannabis, recent weeks have seen mixed developments under the Trump administration.
Late last month, for example, a university that has for decades held a monopoly as the only institution federally authorized to grow marijuana for study purposes announced the launch of a new, collaborative cannabis research center it will host with the help of a federal grant.
The University of Mississippi was been selected to house the National Institutes of Health’s (NIH) Resource Center for Cannabis and Cannabinoid Research (R3CR), which the federal agency first announced in late 2023. The college will be partnering with Washington State University (WSU) and the United States Pharmacopoeia (USP), with support from a grant awarded by the National Center for Complementary and Integrative Health (NCCIH) under NIH.
Ole Miss will lead the effort’s regulatory guidance core, while WSU will handle research support and USP will focus on research standards.
Earlier this week, however, the controversial Department of Government Efficiency (DOGE) touted the cancellation of another marijuana-related federal grant—this time targeting a program that’s long tracked cannabis potency levels in seized illicit products.
The contract had historically been awarded to the University of Mississippi. But it’s also received funding through the National Institute on Drug Abuse (NIDA) to monitor cannabinoid content such as THC and CBD in confiscated cannabis.
That contract has now been ended as part of DOGE’s mission to make significant government spending cuts.
“In the last two days, agencies terminated 148 wasteful contracts with a ceiling value of $420M and savings of $198M, including a $143K HHS contract for the ‘potency monitoring of confiscated marijuana samples,’” DOGE said in an X post on Monday.
The contract cancellation comes about two months after DOGE separately promoted the end of a grant meant to fund a study examining cannabis use risks among LGBTQ+ individuals, non-binary people and heterosexual women.
Many advocates had hoped that, rather than inhibiting cannabis research, Elon Musk and his team at DOGE would seek to cut costs by targeting agencies such as DEA that have perpetuated marijuana criminalization.
Instead, DEA has ramped up recruitment—recently urging people to join them on the frontlines of the “war on drugs,” even if they currently work as a “coffee barista” or otherwise have a non-law enforcement background.
It was also recently revealed that “marijuana” is one of nearly two dozen “controversial or high-profile topics” that staff and researchers at the National Cancer Institute (NCI) are required to clear with higher-ups before writing about, according to a leaked memo from within the federal agency.
DOGE’s Musk, meanwhile, said in February that he thinks it’s a “great idea” to mandate drug testing of federal employees as he pushes to make massive cuts to government agencies and spending.
In response, a Democratic congresswoman filed a bill that would require Musk and other DOGE workers to submit to drug testing to maintain their “special government employee” status.
While DOGE has made cannabis research-related grant cuts, the U.S. Department of Veterans Affairs (VA) recently announced that it’s looking for contractors to analyze and explain scientific evidence on medical marijuana to clinicians and the general public as part of its Systematically Testing the Evidence of Marijuana (STEM) project.
Photo courtesy of National Institute of Standards and Technology.
