This article was originally posted on October 1, 2020 and featured in the 2021 Best Lawyers in the Midwest publication. 

As the landscape for the legalization of marijuana continues to change, businesses—particularly those with multiple locations in different states—are forced to rethink zero-tolerance attitudes and revisit drug testing policies.

Under federal law, all cannabis or marijuana is illegal to sell, possess, or use. However, the federal government has been reluctant to enforce these laws on the basis that many states, including the District of Columbia, permit medical marijuana and, in some instances, recreational marijuana. Several states have now passed laws legalizing marijuana in varying degrees, including some laws that now limit an employer’s ability to terminate an employee for failing a drug test. 

In Illinois, the Cannabis Regulation Tax Act (CRTA) permits the personal and recreational use of cannabis for all individuals 21 years of age or older. Under the CRTA, employers are allowed to terminate workers who bring cannabis to the office, show up to work impaired, or fail random drug tests. When an employer takes any action against an employee for being under the influence of marijuana, the CRTA requires that an employee be provided a reasonable opportunity to challenge the basis of an employer’s determination. 

The Michigan Regulation and Taxation of Marijuana Act (MRTMA) decriminalizes the recreational use of possession of marijuana for anyone over the age of 21. However, the employer has the right to create a policy banning the use of marijuana, test for marijuana usage, and discipline or terminate for breaking the marijuana policy. The MRTMA does not require the employer to permit or accommodate conduct otherwise allowed by the MRTMA in any workplace or on the employer’s property.

Ohio offers identification cards to patients or caregivers who have a certified physician submit an application on their behalf and who have been diagnosed with a qualifying medical condition. In Ohio, employers are not required to permit or accommodate an employee’s use, possession, or distribution of medical marijuana at work.

In Indiana, there are limited protections for Cannabidiol (CBD) only. Indiana is among a limited number of states that have passed limited protections related to the medical use of cannabidiol oil (a plant extract of marijuana). In Indiana, the sale and possession of industrial hemp extract that contains no more than 0.3 percent tetrahydrocannabinol (THC) and no other controlled substances (Ind. Code Ann. 24-4-21-1 to 24-4-21-5) is permitted. Only Purdue University is allowed to cultivate hemp for research purposes. The Indiana law provides no protection to workers testing positive for THC in an employer drug test.

It’s important to note, that regardless of state law, federal rules require substance testing, including for marijuana, of certain employees such as truck drivers. Employers subject to federal regulation can randomly screen employees and include drug testing as part of the hiring process. Companies with federal contracts and grants, as well as federal agencies, must have a drug use policy that is enforced.

Employers have the right to maintain drug-free and alcohol-free workplaces, which includes testing applicants and employees and should clearly state the same in their workplace policies. Regardless of the level of legalization, the key issue for employers involving marijuana is not the legalization itself but workplace safety.

Unlike alcohol, a positive test result for marijuana is very difficult to detect and test for when determining if the drug usage is during work or on non-work hours. THC can remain in the bloodstream for weeks after use, so a positive test may not mean that the employee is impaired at the moment. This also assumes that the marijuana does not prevent the employee from doing his or her job and does not affect the safety of the employee, other employees, the public, or anyone else in the workplace.

In a 2015 article published in the Journal of Occupational and Environmental Medicine, studies showed that individuals who test positive for marijuana have 55 percent more industrial accidents. According to the Journal of the American Medical Association, such individuals have 85 percent more injuries and 75 percent more absenteeism.

Currently, there is no real consensus over how much THC in an individual’s system results in impairment. Alcohol impairment is more clearly defined. For example, federal rules set .04 percent blood alcohol readings as a violation for workers in jobs such as driving trucks or forklifts. Most private companies generally use a range somewhere between .02 and .04 percent. Companies and the medical community, need to figure out what level of THC in an individual’s system indicates that someone is at work in an impaired state. 

If a drug test is positive for THC, a medical review officer should verify the results as positive unless the individual has a prescription for medications that can cause a positive test. Some experts have found that it is possible that over time, small amounts of THC in CBD products could build up in an individual’s body to reach detectable levels because THC is not immediately metabolized by the body, and over time, THC will be slowly released. As a result, it is possible to test positive for THC even after you have stopped taking the product. Again, however, none of this is an excuse for a failed test under most state laws.

Marijuana remains on the federal books as a Schedule 1 drug. But, as the laws on marijuana continue to evolve, employers should remain diligent in reviewing drug testing policies to ensure compliance. Given the ambiguity, here are some best practices for employers:

  1. Do not tolerate marijuana use on the job, just as you would not tolerate alcohol use.
  2. Train your managers and supervisors to identify signs of impairment.
  3. Determine which type of testing your company uses, and stay on top of developments in technology of testing, particularly in determining acceptable THC levels.
  4. Understand that testing policies may need to vary by location to remain compliant with state law.



An employment attorney at Barrett McNagny, Taliesin “Tess” P. Anglin works with employers on employment contracts, claims involving the Americans with Disabilities Act (ADA), the Family and Medical Leave Act (FMLA), the Fair Labors Standards Act (FLSA), and the Indiana Worker’s Compensation Act. Prior to joining the firm, Tess served as a Senior Law Clerk for the Worker’s Compensation Board of Indiana. She can be reached at