A 6-step Guide to Managing the Risk of Cannabis Impairment


Sept 11, 2019

By Kristin Onorato and Larry Masotti

The legalization of recreational cannabis has given new life to an ongoing workplace concern: how to reduce the risk of impairment.

Many workplaces are still struggling to navigate the balance between managing the effect of the cannabis legislation while also protecting employer rights. Safety should always come first. All employees must show up to work fit for work and remain so throughout their shift. This requirement applies to those who use recreational drugs, prescription drugs or alcohol.

Hazards involved

Acute effects of impairment include diminished mental alertness, physical coordination, reaction time, sustained vigilance, manual dexterity and judgment — all essential requirements for working safely and productively.

Cannabis contains over one hundred of chemical substances, including Delta-9-tetrahydrocannabinol (THC) and Cannabidiol (CBD). Although medical cannabis may have lower amounts of THC (responsible for the psychoactive response), it may have an impact on how the brain and body function.

The effects of cannabis impairment are usually more subtle and longer lasting than alcohol impairment and may be harder to recognize. But in both cases complex human/machine performance such as driving vehicles or operating machinery will be impacted by impairment.

Impairment from THC may last as long as 24 hours after taking a moderate dose of cannabis products and effects can linger for frequent users.

Cannabis available as edibles (e.g. candy, baked goods) increases the risk of accidental consumption, impairment and overdose.

Studies have linked the consumption of products high in THC to an increased risk of mental illness.

What you can do

Most workplaces already have a drug and alcohol policy prohibiting substance use. That’s a great starting point. You can use that foundation to manage impairment from many sources, including cannabis, over the counter and prescription drug use, stress and fatigue.

Here are six steps to help manage impairment in the workplace:

1. Update or conduct fresh hazard assessments to include impairment. This requires having a clear understanding of which positions are considered safety sensitive.

2. Develop an impairment policy that

• defines impairment

• defines fitness for work and requires employees to be fit for work

• outlines the consequences, up to and including termination, for anyone not fit for work

• includes supports for any employee struggling with addiction

3. Train all employees on the signs of impairment, the risks and the company’s policy. Make sure that people understand what impairment in the workplace is, what fit for duty is, and what safety sensitive positions are. This helps everyone understand what’s expected of them.

4. Develop and communicate procedures for identifying, reporting and removing impaired employees from the workplace. Create an environment in which employees feel safe and comfortable bringing personal concerns forward. Perhaps they’re taking medication that might make them impaired, or they believe a co-worker may be impaired and is a hazard to themselves and others.

5. Determine how you will accommodate employees who disclose substance use, in line with human rights legislation. Employees need to know they are required to inform the employer. Then the employer can devise an appropriate response, such as implementing modified or return-to-work programs, and connecting the employee with internal and external supports, such as employee assistance programs (EAPs), community agencies and local health units.

6. Train supervisors on how to identify and respond to work-related impairment. Correctly identifying impairment is the first step in taking preventive action.

For more on cannabis and impairment, download an information sheet here.

Kristin Onorato is a health and safety consultant with WSPS. Larry Masotti, also with WSPS, is Director, Strategic Relationships. WSPS, a not-for-profit organization serving Ontario’s manufacturing, agricultural and service sectors, works with companies to create or revise policies and procedures and provide guidance on how to address the potential risk for impairment as part of a hazard/risk assessment. Check out WSPS’ online Small Business Centre, which offers many resources at no cost to help small businesses create or improve their health and safety program.

Photo by Esteban Lopez on Unsplash

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