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Legalized marijuana and workplace testing

June 3, 2014
by Jo McGuire
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With increasingly relaxed attitudes toward marijuana legalization in the United States, some employers are evaluating their drug screening protocols and wondering if it is time for a change. One Floridas contractor recently made this observation to a drug test provider: "What people do on the weekend is no business of mine. If they are using pot, who am I to judge? So long as they don't come to work high."  

Should statements such as this give one pause about drug and alcohol testing of employees? How should we address worries about crossing the line into invasion of privacy?

Employers should consider that in 1991 a study was conducted with nine airline pilots, some of whom smoked a marijuana cigarette containing 20 mg of delta-9-tetrahydrocannabinol (THC) while others were given a placebo. The pilots flew in an aircraft simulator prior to smoking, 15 minutes after using marijuana, and again 4, 8 and 24 hours post-smoking. Seven of the nine pilots showed some degree of impairment 24 hours after smoking what was considered to be a moderate, “social” dose of marijuana. However, only one pilot reported awareness of impairment after 24 hours; the others were unaware that impairment was still affecting their skills.

Why does this study matter? Officer Glenn Thomas of the Colorado Springs, Colo., Police Department responds, “The high, as we call it, is not the same as impairment; this is widely misunderstood.” Thomas is a drug recognition expert for law enforcement, training police to recognize drugged drivers. He asserts that most people believe they can safely drive, operate machinery or perform similar tasks as long as they are not experiencing the immediate “high” one gets while using cannabis products.

“People assume once that four-to-six hour window has passed, everyone is good to go. This thinking is what gets people hurt,” Thomas says.

Processing the new law

Indeed, workplace impairment stands at the forefront of recent discussions in Colorado, where recreational marijuana use has been legalized for individuals 21 and older. While most employers in the state agree they do not want to create work environments full of perceived “stoners,” many are questioning whether to allow some reasonable amounts of THC to be present in an employee’s system.

For instance, the Pueblo City Council intends to allow recreational marijuana sales within the city limits, and council members are trying to determine what the allowable amount of “presence in system” testing should be for city employees who do not work in safety-sensitive positions.

For further consideration of this important topic, the amount of THC content in marijuana must be discussed. The aforementioned study of pilots occurred at a time when THC levels typically were at 2 to 3% in a standard marijuana cigarette. Today’s products are in excess of 15% THC, with some edibles and oils reaching well in excess of 50%. Laboratory results for employees in Colorado who used to test positive at 100 ng/mL of THC in urine drug screens are now frequently showing positives at upwards of 1,000 ng/mL.

Another new factor Colorado is grappling to understand involves how THC in edibles affects the consumer in terms of impairment. Delayed impairment after consumption and length of impairment time vary greatly, not to mention that edibles can easily be consumed on the job without notice by the closest of observers.

Reports of what some would consider extreme side effects also are surfacing as the marijuana industry races to create increased potency in edibles. Some news coverage in Colorado has reported on experiences of hallucinatory episodes and erratic behavior not associated with our typical assumptions about marijuana-influenced behaviors.

While we hope most responsible individuals would recognize it is not wise to consume marijuana edibles at work, the edibles creator Sweet Grass Kitchen advertises on its website that its THC-infused oatmeal raisin cookie is “perfect for those who like to medicate in the morning.” The great marijuana experiment of Colorado is proving to find many individuals willing to push the boundaries that regulation promises.

Policy implications

If we combine the notions of legalized marijuana and allowing THC to be present in an employee’s system (with the knowledge of increased impairment time to include a minimum 24-hour window), we must ask whether employees will respect a boundary of “no marijuana products 24 hours prior to work time.” And if not, is it acceptable to allow some level of employee impairment at work?

Understand that according to the Substance Abuse and Mental Health Services Administration (SAMHSA), drug use costs U.S. businesses upwards of $100 billion annually. In addition, the U.S. Department of Health and Human Services (HHS) states that employees who test positive for marijuana sustain 55% more industrial accidents and 85% more injuries.

The costs of allowing THC in employees' systems must be measured against the benefits. But it really comes down to this question: What is safe? The answer is that no one really knows. There exists no standard by which to measure.

In Colorado, the “Driving Under the Influence of Drugs” standard has been set at 5 ng/mL for blood draw results. But cannabis users build up tolerance in their system and, as with alcohol, some can be very high-functioning even with amounts of THC in their system that would highly impair an infrequent or new user.




This is a very contentious area, so comments on it are in order. This article is disappointing as if appears to suffer from the plague of questionable research funded by federal monies directed at an agenda that supports a failed "war on drugs." No reference is provided for the research on pilots, so its hard to evaluate the writer's assertions about impairment. The same is true for the brain impairment research. Without robust discussion of the research one is left with the question of whether the data has been "cherry picked" to support a point of view.