While cannabis use is now legal in many US states, there is as yet no reliable test to determine whether, or how far, a user may be “under the influence”. And this is major issue for many employers, as well as for the legal system.

Major companies such as Amazon are moving away from screening potential staff for cannabis use before employing them though they must still do so for certain positions, such as those regulated by the Department of Transportation.

Amazon also still tests employees after accidents or due to “reasonable suspicion” at work “to ensure full compliance with industry standards, regulations, and accreditation,” according to the company’s senior vice president of human resources, Beth Galetti.

However, decisions based on cannabis impairment testing remain controversial as there is still no dependable, scientifically rigorous test. Existing tests show only whether metabolites are present in someone’s system, not how they may be affected.

As Michael Milburn, professor of psychology at the University of Massachusetts Boston, notes: “The current drug and sobriety tests do not reflect the best science or public policy.”


‘Presence does not mean impairment’


This is because, unlike alcohol, cannabis indicators can remain in the system for significantly longer periods of time as cannabis is fat-soluble.

Jane Terry, vice president of government affairs at the National Safety Council, said: “There is no scientific test for impairment from cannabis.

“Policymakers and others think that because we can test for alcohol, it can be done for cannabis. But cannabis goes to your fat cells. Presence does not mean impairment it can stick around for days or weeks. But because you can’t test impairment, it is challenging for employers to figure out how to react if someone is using on the job.”

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    The Supreme Court of New Jersey is currently reviewing Drug Recognition Evaluation (DRE), with potential nationwide ramifications.

    According to attorney Evan Levow, who filed an amicus brief on the issue for the DUI Defense Lawyers Association, the DRE is “a cobbled-together process of medical assessments by non-medical personnel, use of field sobriety tests that are not validated for drug testing, and toxicology, usually urine testing, that doesn’t include quantitative amounts of the presence of the substance the individual is alleged to be under the influence of. Statistics show that DRE results are less than 50% reliable.”


    ‘A glass of wine two weeks ago’


    These same DRE protocols heavily influence impairment testing protocols used in the workplace.

    “Cannabis compounds can linger in the body for weeks, if not months. That makes failing a marijuana drug test akin to failing a sobriety test because you had a glass of wine two weeks ago,” said Melissa Moore, director of civil systems reform at the Drug Policy Alliance.

    In the absence of clear guidance from federal or state legislatures, courts around the country are currently looking at this issue in terms of how such determinations can be made, and at the scientific validity of how police detect drug impairment.

    While the National District Attorneys Association sends out materials that include “helpful” questions for use during voir dire hearings, at which a judge may determine whether evidence is admissible, the science is not there to back them up.

    James DeLise CBD-Intel contributing writer

    Photo: Carlo Raso

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    CannIntelligence contributor.