The federal agency for science has changed the date of a workshop that was intended to facilitate “an open, candid and honest discussion” on how technology can be developed and implemented to detect marijuana inhalation.
This event was initially scheduled for Boulder, Colorado. It is hosted by NIST, which is part of U.S. Department of Commerce. NIST officials told MEDCAN24 a full month in advance of the event originally planned that the workshop would be “rescheduled for the summer. Date TBD.”
The agency has announced that the workshop will be held on September 25-26. It will be held at the same location—NIST’s Boulder office.
NIST’s new announcement stated that it would bring together representatives from the government, forensic labs, industry, academics, law enforcement agencies and standards organizations for an open, candid and honest discussion to help achieve meaningful cannabis breathalyzer technologies and their implementation.
NIST sent a draft agenda to MEDCAN24 earlier this year. Topics to be covered include the challenges of designing and developing marijuana breathalyzers, the obstacles that prosecutors face when handling cases involving drugged driving, and ways NIST can partner with others to further advance technology.
The findings of the workshop “Building A Path Forward For Meaningful Cannabis Breathalyzer Reality” will be included in a NIST report, which the agency says it plans to make public.
There is no universally accepted test for determining if someone has been under the influence.
In 2023, a federally funded report by researchers at NIST and the University of Colorado Boulder concluded that evidence does “not support the idea that detecting THC in breath as a single measurement could reliably indicate recent cannabis use.”
Kavita Jeerage said that more research was needed before a cannabis breathalyzer could produce meaningful results. She is a materials researcher at NIST and coauthor of the study. A breathalyzer is a powerful tool that can make a big difference in a person’s daily life. People should be confident about the accuracy of results.
More recently, a U.S. Department of Justice researcher cast doubt on whether a person’s THC levels are even a reliable indicator of impairment.
Frances Scott of the National Institute of Justice Office of Investigative and Forensic Sciences (NIJ), under DOJ said that “states may need to get away from this idea” on a recent podcast.
Scott has questioned whether the “per se”, THC-based limits that have been set by some states for drivers are effective. This allows a driver to be accused of driving under the influence if they exceed the THC limit. It may be impossible to determine impairment caused by THC, as there is with alcohol.
Scott noted that there is a complication: “If you compare chronic and infrequent marijuana users, their THC levels are very different.” Scott also said the effects of these users were different. Scott said that “the same level of effects, if you like, is correlated to a different THC blood concentration in a chronic user as compared to an infrequent use.”
That issue was also examined in a federally funded study last year that identified two different methods of more accurately testing for recent THC use that accounts for the fact that metabolites of the cannabinoid can stay present in a person’s system for weeks or months after consumption.
THC impairment has been an important topic for legislators and researchers, especially when it comes to driving laws.
Last October, a study preprint posted on The Lancet by an eight-author team representing Canada’s Centre for Addiction and Mental Health, Health Canada and Thomas Jefferson University in Philadelphia identified and assessed a dozen peer-reviewed studies measuring “the strength of the linear relationship between driving outcomes and blood THC” published through September 2023.
The paper concludes, “Consensus is that blood THC does not correlate linearly with driving.” The paper concluded that this is “surprising given the fact that blood THC was used to detect marijuana-impaired driving”.
The majority of states with legal cannabis measure THC intoxication based on whether someone’s THC blood levels fall below a specific cutoff. According to the study, relying solely on blood THC levels may not be an accurate way of determining whether someone is driving impaired.
Ten of the twelve papers reviewed in this review found that there was no relationship between the blood THC level and driving performance, or other measures. [standard deviation of lateral position (SDLP)]The two papers that did find a significant association were from the same study and found significant relationship with blood THC, SDLP, speed and following distance. Two papers found a significant link between SDLP (serum THC) and blood, as well speed and distance.
Earlier last year, researchers behind a federally funded study said they’d developed new procedures to enhance the selectivity of a popular forensic testing method, allowing better detection of delta-9 THC and its metabolites in blood.
In a 2023 report on a Transportation, Housing and Urban Development, and Related Agencies bill, the House Appropriations Committee stated that it “continues support development of an object standard to measure cannabis impairment and related field sobriety tests to ensure highway security.”
A year earlier Sen. John Hickenlooper (D) of Colorado sent a letter to the Department of Transportation (DOT) seeking an update on that status of a federal report into research barriers that are inhibiting the development of a standardized test for marijuana impairment on the roads. The department was required to complete the report under a large-scale infrastructure bill that President Joe Biden signed, but it missed its reporting deadline.
A study published in 2019 concluded that those who drive at the legal THC limit—which is typically between two to five nanograms of THC per milliliter of blood—were not statistically more likely to be involved in an accident compared to people who haven’t used marijuana.
Separately, the Congressional Research Service in 2019 determined that while “marijuana consumption can affect a person’s response times and motor performance … studies of the impact of marijuana consumption on a driver’s risk of being involved in a crash have produced conflicting results, with some studies finding little or no increased risk of a crash from marijuana usage.”
Another study from 2022 found that smoking CBD-rich marijuana had “no significant impact” on driving ability, despite the fact that all study participants exceeded the per se limit for THC in their blood.
Evan as far back as 2015, a U.S. National Highway Traffic Safety Administration (NHTSA) concluded that it’s “difficult to establish a relationship between a person’s THC blood or plasma concentration and performance impairing effects,” adding that “it is inadvisable to try and predict effects based on blood THC concentrations alone.”
In a separate report last year, NHTSA said there’s “relatively little research” backing the idea that THC concentration in the blood can be used to determine impairment, again calling into question laws in several states that set “per se” limits for cannabinoid metabolites.
The report noted that although several states had established legal definitions per se of marijuana impairment, there was relatively little scientific evidence supporting their link to accident risk. The report said that contrary to the consensus of research which establishes an obvious correlation between [blood alcohol content] “Drug concentrations in the blood do not directly correlate with driving impairment.”
Testing for marijuana impairment also affects the federally-regulated trucking sector. Last month, for example, a policy paper from two companies said the sector was short about 80,000 drivers last year—an issue it asserted was made worse by workers testing positive for marijuana under the federal Department of Transportation’s (DOT) strict, zero-tolerance drug policy.
A significant number of other qualified drivers failed pre-employment and random drug testing due to marijuana usage, the report noted. These drivers may not be aware of the DOT’s zero-tolerance drug policy, or they might mistakenly think that marijuana is legal in their state and therefore acceptable by federal law.
Drug testing is required by DOT for commercial truck drivers, whether they are hired, randomly selected, or suspected to be impaired.
DOT finalized new testing policies in 2023 to allow oral saliva drug testing as an alternative to urine-based tests. This past December, critics lamented that more than a year and a half after finalizing the rule, federal officials had yet to set up the infrastructure necessary to allow the new testing procedure to be used.
At congressional hearings, earlier this year, members of Congress heard also from trucking representatives who called for a wider adoption of hair-follicle test in the industry. The National Transportation Safety Board’s (NTSB) chair recommended improved education for drivers.
“At time when conversations lean towards the potential reclassification of marijuana from a Schedule I to Schedule III narcotic, demonstrating that this problem is likely to only grow,” said a representative for Truckload Carriers Association, “our industry in its entirety is unable to properly employ the proper test to identify habitual users and enter them into a substance abuse program and begin the return-of-duty procedures.”
The representative explained that some motor carriers use hair follicle tests as part of their policies. However, positive results cannot be entered into a federal DOT data base, so “these drivers can work for another carrier immediately when using only urine testing.”
The transportation industry also advised Congress in January that if marijuana is federally rescheduled, businesses want assurances that they won’t have to forgo zero-tolerance drug policies for drivers—while stressing that a key problem for the sector is a lack of technology to detect impaired driving.
A representative from the Governors Highway Safety Association also raised the issue of driving while impaired by marijuana at a recent hearing of Congress. He stressed the importance of drug tests on the roadside as a way to combat fatal car accidents.
Last month, meanwhile, the U.S. Supreme Court ruled in favor of a trucker who sued a cannabis company after he was fired over a positive THC test that he said was caused by consuming a hemp-derived CBD product.
Separately, a Substance Abuse and Mental Health Services Administration (SAMHSA) official recently downplayed criticism from the CEO of a drug-testing company that more widespread use of saliva-based drug testing “means truckers who use cannabis will be able to do so with near impunity, as long as they avoid a drug test for a couple of days.”
Unidentified SAMHSA officials responded: “When donors receive a collection request, they will not be able to tell if it is a collection of oral fluids or urine until they reach the facility where the federal agency collects the samples.” In other words, not knowing if a urine or saliva test is expected would stop drivers from stopping their marijuana use just a few weeks before the test.
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