Is Marijuana Testing Going Up In Smoke?


by Todd Simo, M.D.

Drug testing has been part of the fabric of employment screening since the mid-1980s. Since then, there has been a natural ebb and flow regarding how companies approach drug testing. With the ever evolving trend of marijuana decriminalization for medical and recreational purposes, many employers are confused about what they can do from a testing perspective. The questions that employers are considering are as follows:

  • Keep testing for drugs using panels that contain marijuana testing
  • Remove marijuana from your testing panels
  • Discontinue drug testing altogether

To state the obvious, as a motor carrier, you have a DOT requirement to test for drugs pursuant to the Omnibus Transportation Act of 1991. That panel includes testing for marijuana. Along with mandating marijuana testing, DOT makes it easy from a result perspective since it does not allow any form of decriminalized to be a medical explanation that your medical review officer (MRO) can accept. However, along with your regulated employees, most motor carriers also employ a virtual army of non-DOT regulated employees. What do you do in these circumstances?

Before answering that question, let’s look at why companies started drug testing in the first place. The answer is profoundly easy: substance abuse has a negative impact on their workforce. For safety-sensitive organizations, including transportation and manufacturing, substance abuse markedly increases their workplace injury rate. For white collar employers (finance and retail), one of the major drivers to maintain a drug testing program is reduction in “shrinkage” (a term used to describe theft of company assets). U.S. Chamber of Commerce data shows that illegal drugs are bought by money diverted from legitimate businesses. The dollar value of that theft could amount to as much as $100 billion a year.

Along with these reasons to drug test, here is a list of other advantages that companies with a drug-free workplace appreciate:

  • Reduces employee turnover and recruitment costs
  • Improves staff morale
  • Reduces potential workplace conflict/violence
  • Helps educate workers about the dangers of drugs
  • Deters workers from using/abusing drugs
  • Creates a healthier workplace (reduces health insurance costs)
  • Boosts the reputation of your organization

Drug testing, like any other form of pre-employment/post offer candidate vetting, is based on a return on investment. For every organization that screens candidates, the primary goal is a mixture of brand protection, risk mitigation and company safety culture. There are multiple screening tools/products that companies may use based upon their requirements.

Even though the attitude about drug testing at the employer level has not markedly changed, several employers now struggle with the question of whether marijuana testing should be part of their testing regimen. The reasoning here is based on a confluence of several factors:

  • The majority of states have a medical marijuana statute in place (14 of those states mandate consideration of accommodation of medical marijuana users despite a positive drug test).
  • Fifteen states now (or will shortly) have completely decriminalized marijuana for recreational use.
  • The majority of Americans are in favor of medical marijuana.
  • There is an emerging trend of American acceptance of marijuana as a legal substance.

Along with these facts, there are several myths that are being propagated as to why employers should not test for marijuana.


The labor market is always tight. Even when unemployment is low, there is always competition for talented candidates.

There has been a lot of press about anecdotal reports of employers not being able to find candidates in areas of decriminalized, recreational use, such as Denver, CO. Based on the Quest Diagnostics Drug testing index, well over 90 percent of all drug tests collected in Denver were negative for THC at the lab level; therefore, the vast majority of people in the Denver area have no problem passing a drug test.


There is a plethora of misinformation out there about marijuana testing. Some people even opine that the marijuana tests are imperfect. Many believe that traces of cannabis remain in a person’s body for a number of weeks (even months) after a single use. With this belief, there is no way anyone can state how long ago someone last used pot, or the frequency of use. The reality of the situation is that the detection window for marijuana use is small for two of the three predominant drug testing specimens.

  • A urine drug test utilizing the standard employment cut-off levels has a detection window of only seven days for the vast majority of chronic smokers. The information showing that users will stay positive for 30 days or more is based on testing techniques that are not the same as a standard drug test.
  • Oral fluid’s detection window is less than 24 hours after last use. That detection window is actually less than the known impairment window for marijuana; therefore, a positive oral fluid test is a strong indicator of impairment.
  • Hair tests can have a detection window of approximately 90 days if the donor’s specimen length is 1 1/2” or greater. However, THC and itsits metabolites do not deposit in hair all that readily. For a hair test to be positive for THC,the donor had to have a significant degree of exposure to THC, far beyond episodic use.

With consideration of these detection windows, if a company is concerned about workplace impairment, but not sporadic use, oral fluid is the right tool for their program. Also based on these detection windows, donors who test positive in urine tests who state they quit 30 days ago and donors who claim they only smoked once that are positive in hair are in all likelihood not being completely truthful.


Much of the push for marijuana legalization is based upon contentions that marijuana is safe and causes no safety concerns if used during off duty hours. Unfortunately, these statements are as false as the hyperbolic films like Reefer Madness (that depict marijuana users automatically becoming criminals). The documented negative health effects are as follows:

  • Short-term effects:

– Distorted perception (sights, sounds, time, touch)

– Problems with memory and learning

– Loss of coordination

– Trouble with thinking and problem-solving

– Increased heart rate

– Marijuana use can also produce anxiety, fear, distrust, or panic

  • Long-term use effects:

– Effects on the brain (hallucinations, delusions, impaired memory, disorientation)

– Effects on the heart (increased risk of heart attack)

– Effects on the bones (People who smoke large amounts of marijuana on a regular basis have reduced bone density and are more prone to getting fractures.)

– Effects on the lungs (chronic bronchitis)

Looking at any of the short-term effects, one would surmise that marijuana is impairing when the person is acutely intoxicated (generally a period of approximately four hours from use); however, the impairment window of marijuana has been shown to be considerably longer than that four hour window. An article in the Journal of Occupational and Environmental Medicine1 concluded after review of multiple studies that, “there is now a large body of evidence to support the persistence of neurocognitive impairment lasting from hours to weeks” after marijuana use.


According to the Society for Human Resource Management (SHRM), “Experts agree that whether or not employers decide to test for marijuana pre-employment, having a clear, well-thought-out drug testing policy addressing marijuana is a good idea.”

SHRM also stated that, “…if employers decide against a zero-tolerance policy on marijuana, HR should assess a candidate’s ability to perform the required job functions and review whether a reasonable accommodation is applicable or required by federal and state disability rights laws, experts said.”

Nolo, a publisher of legal guides of individuals and small businesses, offers a state-by-state summary of laws pertaining to off-duty medical marijuana use.

Most importantly, organizations should consider consulting legal counsel thoroughly conversant with the latest changes in legislation regarding hiring and marijuana.


  • Know the laws covering marijuana use in states in which you employ people. Some states require that you consider accommodation for decriminalized marijuana users (a positive drug screen for marijuana is not automatically disqualifying in these states).
  • Know your risk tolerance/employee profiles. Ability to accommodate may be vastly
    different based upon the safety-sensitive duties of those employees (all employees who work under one job description should be treated
    the same).
  • Know the regulatory rules that apply to your company. Companies may be prohibited from offering accommodation to decriminalize marijuana users based upon federal rules and contractual constraints.
  • If you are in states that require consideration of accommodation or desire a test that provides you the ability to make a determination of impairment based on a marijuana-positive drug test, consider performing an oral fluid test.

– The detection window for oral fluid drug tests is less than the impairment window. If the donor is positive on oral fluid, it is scientifically supported that the donor was impaired at time of collection.

– Every state that requires consideration of accommodation for decriminalized marijuana use allows employers to not hire/terminate candidates/employees who are impaired on the job site.

As marijuana laws change across the country, it is vital for employers to have a comprehensive, legally acceptable drug policy that clearly addresses decriminalized marijuana use.




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