Is Marijuana Testing Going Up in Smoke?

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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 in regard to how companies regard drug testing. HireRight’s 2018 Vertical Industries Spotlight Report, based upon data received from nearly 6,000 HR professionals, found that the vast majority of employers in the Finance (80%), Manufacturing (78%), and Retail (80%) sectors test their candidates for drug use.  Our survey also revealed that 41% of employers in both Manufacturing and Retail tested executives for drugs and alcohol. Following that trend, 37% of Finance and 38% of Manufacturing organizations tested their extended workforce (contract, contingent and/or temporary workers).  One hundred percent of all federally regulated Transportation clients are mandated to operate a drug-free testing program for their safety-sensitive workforce to comply with the Omnibus Transportation Act of 1991.

What do Finance, Manufacturing, Retail and Transportation employers all have in common?  All four are acutely aware that 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).  There is U.S. Chamber of Commerce data that 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 the above reasons to drug test, here is a list of other advantages that companies with a drug free workplace appreciate:

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

Although there are many pros to having a drug-free workplace that includes drug tests, there are some industry verticals that have shied away from it. In juxtaposition to the above verticals, Education is less likely to conduct drug testing. Our benchmark report showed 42% of the Education vertical responders had a pre-employment drug testing program in place with the vast majority of them not testing their top personnel (only 17% of Educational organizations tested their top personnel).

Does Education know something other fields don’t? Is this an indication of a new trend? Is this a response to changing public attitudes?

Probably not…

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

Even though the attitude for drug testing at the employer level is not markedly changed, several employers now struggle if 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
    • Several of those states mandate consideration of accommodation of medical marijuana users despite a positive drug test
  • 10 states now have completely decriminalized marijuana for recreational use
  • The majority of Americans are in favor of medical marijuana
  • The emerging trend of American acceptance of marijuana as a legal substance

Along with the above facts, there are several myths that are being propagated as to why employers should not test for marijuana. Here they are:

Finding Qualified Candidates is More Difficult

The Federal Reserve Bank’s Beige Book1, which provides a summary of economic activity, stated in October of last year that employers are finding it ever harder to recruit qualified candidates.

“Employers throughout the country continued to report tight labor markets and difficulties finding qualified workers,” the report said. Job openings outnumber job seekers. Workers in short supply include highly-skilled engineers, finance and sales professionals, construction and manufacturing workers, IT professionals, and truck drivers.

There has been a lot of press written about anecdotal reports of employers not being able to find candidates in areas of decriminalized, recreational use such as Denver, CO.  Based upon Quest Diagnostics Drug testing index, well over 90% 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 in passing a drug test.

medical marijuana map

Imperfect methods

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, nor 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 ½” or greater
    • However, THC and its 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 the above 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 examinations who state they quit 30 days ago and donors who claim he/she only smoked once that are positive in hair are in all likelihood not being completely truthful.

Marijuana is safe

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:

  • The 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
  • The 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

Just looking at any of the short term effects of marijuana, anyone 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 Medicine2 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.

What should your organization do?

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.”

As HireRight’s Chief Medical Officer, I have written that “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.”.

Some jobs, such as those in Healthcare and Transportation, will always require drug tests; federal law prohibits anyone with a commercial driver’s license from having a medical marijuana card or license that allows the use of the substance. Government contractors will also need to respect federal laws pertaining to drug use, even in states where cannabis is legal. Companies are also reserving the right to test after an accident or if an employee comes to work visibly impaired.

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.”

Nolo3, 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 engage legal counsel who are thoroughly conversant with the latest changes in legislation regarding hiring and marijuana.

Best practice recommendations:

  • 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 which apply to your company
    • Companies may be prohibited to offer accommodation decriminalized 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 oral fluid testing.
    • The detection window for oral fluid drug tests are 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
      • Currently 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


  3. HireRight is not affilated with and does not warrant any statements in these materials.

Find more information about medical marijuana on our Resource Library


Dr. Todd Simo

Dr. Simo is the Chief Medical Officer and the Managing Director of Transportation at HireRight. He served as HireRight’s Medical Director starting in 2009 and was promoted to Chief Medical Officer in 2015. Dr. Simo was also appointed to the role of Managing Director of Transportation in 2018. Dr. Simo came to HireRight with a decade of experience in the medical consulting arena. Before that he was Medical Director at an occupational health clinic in Virginia and owned a consulting firm providing medical director services to employers across the United States.

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