Drug Testing Guidance for Oklahoma Employers Under Medical Marijuana Law

April 2, 2026

Some practical tips regarding drug testing in Oklahoma

Courtney Bru McAfee & Taft + Follow Contact LinkedIn Facebook X Send Embed

In 2018, Oklahoma voters approved the legalization of medical marijuana. This resulted in multiple phases of implementing legislation. Here are a few practical tips for administering your drug and alcohol testing policy.

Tip #1 – Designate safety-sensitive positions for purposes of drug and alcohol testing.

The Oklahoma Medical Marijuana Act provides that, “unless failure to do so would cause an employer the potential to lose a monetary or licensing-related benefit under federal law or regulations, an employer may not discriminate against a person in hiring, termination or imposing any term or condition of employment or otherwise penalize a person based upon the status of the person as a licensed medical marijuana patient.” Okla. Stat. tit. 63, § 425. However, subsequent legislation (the Oklahoma Medical Marijuana and Patient Protection Act, sometimes referred to as the “Unity Bill”) creates an “exception.”

The Unity Bill provides that an employer may refuse to hire, discipline, discharge or otherwise penalize an applicant or employee solely on the basis of a positive test for marijuana components or metabolites if the individual is applying for or employed in a position “involving safety-sensitive job duties.” Okla. Stat. tit. 63, § 427.8(H)(2)(c). The statute defines “safety-sensitive” as “any job that includes tasks or duties that the employer reasonably believes could affect the safety and health of the employee performing the task or others including, but not limited to, any of the following:”

• handling, packaging, processing, storage, disposal or transport of hazardous materials,
• operation of a motor vehicle, other vehicle, equipment, machinery or power tools,
• repairing, maintaining or monitoring the performance or operation of any equipment, machinery or manufacturing process, the malfunction or disruption of which could result in injury or property damage,
• operation, maintenance or oversight of critical services and infrastructure including, but not limited to, electric, gas, and water utilities, power generation or distribution,
• extraction, compression, processing, manufacturing, handling, packaging, storage, disposal, treatment or transport of potentially volatile, flammable, combustible materials, elements, chemicals or any other highly regulated component,
• dispensing pharmaceuticals,
• carrying a firearm, or
• direct patient care or direct child care. Note that this list is non-exhaustive. Other positions can certainly qualify as “safety-sensitive” positions depending on the tasks performed.

Have you expressly designated your safety-sensitive positions as “safety-sensitive?” Consider the following scenario, which was litigated before an Oklahoma court. An individual applied for a job that required him to drive a company-owned vehicle around the state. After interviews, he was given a conditional offer of employment, contingent upon successful completion of a drug and alcohol test. The individual tested positive for marijuana. While the testing and/or results were pending, the individual quit his current job relying on assurances provided by an individual having no role in pre-hiring processes and no authority to deviate from hiring procedures. He was then advised his conditional offer was revoked due to his drug test results. At that point, the applicant provided a medical marijuana card. The employer did not reinstate the offer because the position required the performance of safety-sensitive duties, including driving a motor vehicle. The individual filed a lawsuit. His allegations included reliance upon the promises and assurances of a company employee.

Employers often note that an open position requires successful completion of a drug test as a condition of receiving an offer. But specifically identifying a particular position as “safety-sensitive” – in a job posting, application materials, interview process and job description – can go a long way towards eliminating these types of reliance-based claims. It can also trim your applicant pool and eliminate costs associated with testing applicants who cannot satisfy the conditions of the position.

Tip #2 – Know the lingo: “impairment,” “under the influence,” “impact on performance.”

Marijuana, like other unlawful and/or prescription drugs, impacts persons differently. It is metabolized differently. Marijuana metabolites may remain in a user’s system for an extended period of time – even months – without having any psychoactive impact on the user.

When an individual tests positive for a substance in excess of applicable concentration cutoffs this does not mean the individual was “impaired” or “under the influence” at the time of testing. There exists no universally accepted scientific threshold for equating THC blood levels with “impairment” or being “under the influence.”

As merely one example, in Whitmore v. Wal-Mart Stores, Inc., No. CV-17-08108 (D. Ariz. 2019), a Walmart employee tested positive for marijuana and was terminated. Walmart argued that “upon reasonable belief, Plaintiff’s May 24, 2016 positive test result for marijuana indicated that she was impaired by marijuana during her shift that same day.” A human resource professional submitted an affidavit attesting to this belief. The former employee argued the HR professional lacked the necessary “knowledge, skill, expertise, training or expertise” to form this belief. She also argued that she was not tested for “marijuana” but “marijuana metabolites,” which are “primarily the non-impairing components of THC … that metabolize in urine” and as a result, there was no “correlation between THC and impairment.” While the court addressed the matter on alternate evidentiary grounds, courts around the country have taken a similar view to marijuana test results. You must be aware that a “positive” finding will more than likely not be allowed as evidence of “impairment” or being “under the influence.”

So what good is a positive marijuana test result? In a state like Oklahoma that allows an employer to terminate an employee in a “safety-sensitive” position merely for testing positive, it is a solid basis for termination. And alongside other evidence, such as behavior consistent with marijuana use observed at the time of testing, it can help establish a policy violation. But know the lingo. An employee is not “impaired” simply because that employee tested positive. That evidence may help you prove that you had a reasonable basis to believe that the employer reported to work in a condition that impacted their ability to safely or properly perform their job duties.

This brings us to a third principle…

Tip #3 – Use the senses: not all disciplinary opportunities require testing.

Under Oklahoma’s drug testing laws, an employer can prohibit the use, possession, concealment, manufacture, distribution, dispensation, promotion, transportation, purchase or sale of alcohol or drugs – including medical marijuana – while on the employer’s property, jobsites or vehicles, and/or during working hours. An employer can also require employees to report to work ready and able to perform their job duties safely, without being impacted by the effects of drugs or alcohol.

These types of provisions should be expressly included in your drug and alcohol testing policy. They are very powerful tools for employers. They allow an employer – acting reasonably on the basis of reasonable evidence or observation – to discipline, even terminate, an employer for violation of its policy – without testing the employee.

If an employee reports to work stumbling, slurring words and smelling of alcohol, do you need to test that person to determine they have showed up to work after having used alcohol?  No. And you don’t have to.  If you have reasonable evidence to support your belief, you can rely on that evidence to discipline, even terminate the employee, without sending the employee for testing.

What type of evidence do you need?  I recommend that you borrow from the Oklahoma statute. OKLA. STAT. tit. 40, § 554(2) authorizes “for cause testing” when an employer “reasonably believes that the employee may be under the influence of drugs or alcohol, including but not limited to the following circumstances:

1. drugs or alcohol on or about the employee’s person or in the employee’s vicinity,
2. conduct on the employee’s part that suggests impairment or influence of drugs or alcohol,
3. a report of drug or alcohol use while at work or on duty,
4. information that an employee has tampered with drug or alcohol testing at any time,
5. negative performance patterns, or
6. excessive or unexplained absenteeism or tardiness.” We can borrow from the feds, too.  U.S. Department of Transportation regulations allow for reasonable suspicion drug testing when two or more supervisors concur regarding the evidence forming the basis of a reasonable belief regarding use or impact. While this is not required under Oklahoma law, it is certainly a great practice to have corroboration of the observed behaviors or information received from two or more credible employees (whether supervisors or not). Document this evidence and maintain it in your records.

Drug testing is a helpful tool for employers, but it’s only one tool in the belt. Be sure to consider whether there are other, more appropriate ways to proceed. Avoid pitfalls now and use the right lingo. You’ll be glad you did.

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DISCLAIMER: Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.
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