“But I Only Used One Time, Thirty Days Ago”
When employers feel pressured to loosen-up their drug and alcohol policies to provide more room for the use of marijuana, one popular argument is that presence-in-system testing simply is not fair. We’ve all heard the outcry, “An employee can be fired for smoking weed one time, thirty days ago, and that’s just not right … they aren’t even impaired!”
This leads to demands for an impairment test – or – for an employer to “prove” impairment before taking action based on a drug test result.
These arguments and questions seem reasonable until the truth gets involved.
We essentially have two separate issues to unravel in this conversation. We’ll start with the first, which is the “thirty days ago” scenario for a marijuana drug test. The second – a moment of opportunity is covered below.
One of the most widely misunderstood and often repeated myths is that one-time marijuana use can show up on a drug test thirty days later. This is tantamount to the ultimate trick-question. Far more people fail to see the problems with the statement than those who might fail the drug test.
The key tricky phrase is “one-time use”. The one-time user of cannabis is NEVER going to fail a drug test thirty days later. Not in urinalysis, not in hair, not in oral fluid, nor any other means of drug testing. When using the standard cut-off levels, nearly all urine drug tests will be negative 3-5 days following use.
The confusion comes from chronic marijuana use. Those who partake of marijuana products with regularity (daily to weekly) are considered chronic or heavy users. The chronic user experiences saturation of Carboxy-THC which saturate the fat cells, to include the brain.
When the heavy user ceases cannabis usage it could take weeks for the THC to leave the system and for that individual to produce a clean drug test result.
In no uncertain terms, when one hears the excuse, “I used once thirty days ago” … this is a falsehood. They may have ceased use thirty days ago, but they would have been a heavy marijuana user in order to obtain a positive drug test.
What this means for an employer: this is not a valid excuse for a failed drug test, there is more here than meets the eye. We will explore this further below. In the meantime, make sure your drug and alcohol policy is up-to-date and maintain your drug testing practices with confidence. A drug free workplace policy is an important component of you business, learn more.
Marijuana Positive – A Moment of Opportunity
“But I Only Used One Time, Thirty Days Ago”
When an employer hears the excuse, “I only used marijuana once thirty days ago” as a reason for failing a THC drug screen, it is a moment of opportunity to learn who your employee really is.
It seems the justification for failing a drug test is widely used for two types of situations. The first (and most common) being an individual who is attempting to lay a foundation to claim drug testing is unfair, get their results invalidated and the company’s drug testing policy changed. They may even be threatening a lawsuit.
Many employers feel intimidated and panic, backing down and giving in. This is unfortunate because the science – and precedent setting court decisions are largely on the side of the employer. This type of individual is likely a regular marijuana user who is putting company safety at risk. No matter how long they have been using marijuana, they do experience impairment. The wise choice is to enforce the company drug and alcohol testing policy consistently in spite of an employee’s effort to manipulate.
The second example of an employee who uses the “thirty days ago” defense would be the individual who has ceased using marijuana and is truly striving to respect the company policy. How does an employer differentiate between the two and make good decisions about consequences?
One solution lies in subsequent lab-based testing. The employee who is choosing to be compliant with the rules will likely be agreeable to a series of random tests over a period of several weeks or months that will eventually be THC free. In most cases, the manipulative employee who has no intention of ceasing their drug use will continue to bully and protest.
In an era of change pertaining to marijuana laws it is imperative that employers know their rights and understand how THC is measured in a drug test as well as what solutions may be available in order to retain valuable employees. An informed TPA will be able to offer supportive solutions for maintaining an effective safe and drug free workplace policy, that helps employers to feel confident in knowing their lab-based drug test results are accurate and reliable.
 Workplace Drug Testing in the Era of Legal Marijuana, Institute for Behavior and Health (2014) Washington D.C.
By Jo McGuire
Jo McGuire is a Denver native who served on the Colorado Governor’s Task Force to implement the regulatory framework for Amendment 64, representing employer’s rights to safe and drug free workplaces. As a national expert, she has authored dozens of articles for a variety of trade magazines and is a sought-after conference speaker and webinar presenter on the impact of marijuana in the workplace. Jo is the current executive director of the National Drug and Alcohol Screening Association (NDASA) which is now also DATIA.
“Speak the truth, even if your voice shakes” – Maggie Kuhn
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