Cannabis and Safety: It's Complicated - National Safety Council
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Cannabis and Safety: It's Complicated

Cannabis can have a major impact on the safety of employees and cannabis legalization is creating new challenges for employers. According to a recent NSC survey, one third of employees say they have observed cannabis use during work hours. The survey also found that:

  • More than half of employers that eliminated THC testing reported seeing an increase in incidents or other workplace performance concerns
  • Most employers believe employees would feel comfortable telling their supervisor if they were too impaired to work, while less than half of employees reported they would feel comfortable telling supervisors they were impaired
  • Less than half of organizations have a written policy addressing cannabis

Check out this infographic for more survey findings.

NSC advocates for cannabis safety with a number of policy positions, from workforce drug testing to substance-free workplace policies and programs. See the full list of NSC policy positions related to cannabis.

NSC Recommendations for Employers

As more states legalize cannabis for recreational and medicinal use, employers must take clear, strong stances to ensure worker safety. To help employers address the risks of cannabis in the workplace, NSC encourages business leaders to take key actions that include:

1. Establishing a clear, fair cannabis policy that prevents impairment in the workplace and provides support for employees

2. Building a safety-focused, trusting culture for employees to report cannabis use in the workplace

3. Advocating for increased access to employee assistance programs (EAPs) and health care benefits for those with substance use disorders

4. Training supervisors to recognize and respond to impairment in the workplace; learn more about NSC training at nsc.org/ImpairmentTraining

See additional NSC recommendations for employers to address cannabis in the workplace.

The Effects of Cannabis

Cannabis, like alcohol and prescription opioids, can impact judgment, reflexes and cognitive dexterity, increasing the risk of injury both behind the wheel and in the workplace. The effects of cannabis can vary greatly and may happen quickly or slowly, depending on how it was consumed and an individual’s body composition. It is also difficult to determine how long impairment will last because THC, the psychoactive ingredient in cannabis, is stored in body fat, unlike alcohol, which is stored in the blood.

States with legal recreational or medicinal cannabis are reporting an increase in fatal motor vehicle crashes involving THC. This underscores the importance of educating drivers about cannabis impairment and advocating for more research.

Regardless of legality, employers can set and enforce policies regarding cannabis impairment, usage and possession at work. While carrying small amounts of recreational cannabis in public may be legal in some states, employers are not obligated to allow it in the workplace, even if the employee does not intend to use the substance during work hours.

NSC Resources to Address Cannabis

The following resources can help you learn how cannabis can affect your employees’ ability to work, drive and function, discover policies you should have in your workplace, and get the information and resources you need to address cannabis use and cannabis-related products.

NSC Cannabis Surveys

NSC has conducted surveys to understand public, employer and employee perceptions of cannabis:

  • NSC conducted a survey focused on the impact of cannabis in the workplace. A total of 500 employers and 1,000 employees completed the survey between April and May 2021. Get the survey results.
  • NSC conducted a survey focused on public perceptions of the importance and impact of unintentional or preventable deaths compared to those of other causes of death and injury, including questions focused on cannabis. More than 2,000 surveys were completed between April 30 and May 9, 2019. Get the survey results.

Cannabis Laws by State

Access to cannabis varies widely between states, with some states legalizing cannabis for medicinal or recreational purposes, or both. See an overview of the current cannabis laws by state.

Workplace Costs

Cannabis can have a major impact on safety in the workplace. See the associated workplace costs from cannabis and other substances, then learn more about addressing cannabis use on the job.

Drug-impaired Driving

Driving while using cannabis is dangerous. According to the National Institutes of Health, cannabis significantly impairs judgement, motor coordination and reaction time, and studies have found a direct relationship between blood THC concentration and impaired driving ability.

According to preliminary estimates from the National Highway Traffic Safety Administration (NHTSA), total traffic deaths increased 7% in 2020, and impaired driving was one of the main behaviors driving this increase. Drug- and polysubstance-impaired driving remains a widespread problem in America, with a recent study of five trauma centers revealing that nearly 25% of seriously or fatally injured drivers tested positive for more than one substance. While multiple substances can increase roadway risks, cannabis alone can also create dangerous driving conditions. Since recreational cannabis was legalized in Colorado in 2013, traffic deaths where drivers tested positive for cannabis increased 138% while all Colorado traffic deaths increased 29%.

The science of alcohol impairment is well studied and understood, leading to evidence-based countermeasures to decrease the incidence of alcohol-impaired driving, such as BAC limits and ignition interlock requirements. Cannabis impairment is more difficult than alcohol impairment to quantify and therefore there are few evidence-based limits for cannabis and driving. Additional research and funding is needed on cannabis impairment and cannabis-impaired driving, and much more work is needed to educate the public of the associated risks, particularly as more states legalize recreational cannabis. 

This report describes the review of and updates to the NSC Alcohol, Drugs and Impairment Division recommendations for the toxicological investigation of suspected alcohol- and drug-impaired driving cases and motor vehicle fatalities.