Medical marijuana and workplace safety

On Tuesday, June 20, at Safety 2017, the annual professional development conference and exposition of the American Society of Safety Engineers (ASSE), Fred Kohanna, M.D., MBA, spoke to a crowded room of safety professionals about the workplace safety implications of medical marijuana in a session titled “Medical Marijuana: Miracle Drug or Safety Nightmare?”

According to Kohanna, the Vice President of Occupational Health and Chief Medical Officer at AllOne Health, medical marijuana is not a black-and-white issue; thus, it is neither a miracle drug nor a safety nightmare. Rather, its use poses both potential benefits and workplace safety risks, both of which employers must consider when developing their policies and procedures around employee drug use and drug testing.

Background and uses

Although marijuana remains illegal at the federal level, 28 states and the District of Columbia have legalized it for medicinal purposes, while 8 states and the District of Columbia have legalized recreational use of the drug. In addition, two synthetic preparations have been FDA-approved for specific uses, and two more are being investigated.

Marijuana, or cannabis, has two primary active ingredients: tetrahydrocannabinol (THC) and cannabidiol (CBD). THC and CBD have very different effects in the human body and act on different receptors. While THC receptors are primarily in the brain and affect memory, cognition, and perception of pain, CBD receptors are primarily in the gut and immune cells. CBD can have antiinflammatory, antiseizure, and antinausea effects.

Kohanna emphasized that marijuana is not a first-line drug of choice for any medical condition; rather, it is typically recommended when other therapies have been ineffective or when side effects of other treatments are intolerable. Some of the conditions it has been successfully used to treat include pain, nausea, and lack of appetite associated with cancer, HIV, and AIDS; autoimmune disorders such as rheumatoid arthritis and lupus; chronic neuropathic pain; neuropsychiatric conditions such as epilepsy, Parkinson’s disease, and Tourette’s syndrome; and intractable glaucoma.

There are also important contraindications for use. Pregnant and nursing women should not use marijuana, nor should people with certain other medical and psychiatric conditions or people with a history of substance abuse. There is no definitive evidence that marijuana acts as a “gateway drug” in the way it is often discussed, said Kohanna, but it does have a potential for addiction. About 9 percent of recreational users become addicted.

Workplace safety effects

Notably, Kohanna stated, there have been no reported cases of fatal overdose from marijuana alone, in contrast to opioids and other drugs. However, like any drug, cannabis is associated with a range of side effects. These include panic attacks, seizures, hallucinations, psychosis, sedation, dry mouth, heart palpitations and arrhythmias, and—potentially most worrisome for workplace safety—cognitive impairment and slower reaction times.

Research into the cognitive impairment caused by cannabis use and its effects on safety has shown a variety of results. A 2013 study concluded that marijuana use has a negative effect on learning memory, attention, reasoning, and concentration. In a flight simulator study, pilots showed impaired abilities at 1, 4, and even 24 hours after marijuana consumption. And a 2016 meta-analysis of 21 studies in 13 countries, which incorporated results from over 200,000 participants, found that marijuana use (either self-reported or found in blood, urine, or saliva tests) was associated with at 20 to 30 percent greater risk of a motor vehicle crash.

However, the research is not unanimous in its conclusions. A 1994 survey of 9,000 employees found no association between recent or remote use of marijuana and the risk of work-related accidents. The bottom line is that many questions remain about the effects of cannabis on cognition, behavior, and safety, and employers will need to take all of these potential risks and benefits into consideration.

Policy implications

As more states legalize marijuana, whether for medical or recreational use, employers are challenged with adapting their policies and programs.

An informal poll of the audience revealed that while most in attendance worked for companies with a drug and/or alcohol testing program, only a few had recently made changes to their programs to adjust to the increased prevalence of both medical and recreational marijuana use.

Employers in certain federally regulated industries, such as transportation companies governed by the Federal Motor Carrier Safety Administration (FMCSA), cannot allow employee drug use and are required to conduct drug testing in a variety of circumstances. However, Kohanna suggested that with the trend toward marijuana legalization, a zero-tolerance drug policy might not be right for every organization. Instead, a more flexible policy that balances safety issues against the medical benefits for certain employees might be more successful.

Some of the key considerations Kohanna recommended that employers consider when reviewing drug testing protocols include the following:

  • Differentiate between safety-sensitive and non-safety-sensitive jobs. An employee who occasionally uses marijuana in his or her time off may not pose a problem doing office work, but a more stringent standard should probably be applied to a forklift operator or an employee doing a hazardous confined space entry operation.
  • Consider the reasons for employee use of medical marijuana. Should you allow its use for any employee with a prescription or restrict it to particular types of conditions or diagnoses?
  • Consider the frequency of use, route of administration, and duration of use. The effects of inhaled marijuana peak in 15 to 30 minutes and taper off after 2 to 3 hours, while the effects of ingested marijuana peak in 2 to 3 hours and taper off in 4 to 12 hours.
  • Are there work restrictions or accommodations that should be implemented for employees with a medical marijuana prescription?
  • Consider a policy that requires employees who use medical marijuana to notify the employer of any changes to dosage, frequency of use, or route of administration.
  • Conduct fitness for duty evaluations, including consultation with an occupational health physician and neuro-cognitive testing if necessary.
  • In most cases, don’t allow employees to use medical marijuana on the job or worksite; its use should be restricted to off-duty hours.