Can I be fired for taking drugs at work?

If you’re caught taking drugs at work (or you show up impaired), can your employer dismiss you? The honest answer is: it depends. Ontario’s Human Rights Code protects workers with addiction disabilities, but employers also have legal duties to keep the workplace safe and can enforce reasonable policies about impairment. The right outcome turns on the facts—your role, the substance, impairment, safety risks, and whether addiction is involved.

Below we unpack how the Human Rights Code, safety laws, and real cases fit together—and when discipline or dismissal may be justified.

1) Human rights 101: addiction is protected - recreational use is not

Under Ontario human rights law, drug and alcohol addictions are “disabilities.” Employers cannot discriminate because of a disability or a perceived disability, and must accommodate to the point of undue hardship. By contrast, purely recreational use (with no addiction) isn’t a protected ground—though treating a casual user as if they have an addiction can amount to discrimination based on perceived disability.

Accommodation must be individualized and meaningful. The Code limits “undue hardship” to three factors: cost, outside sources of funding, and health & safety. Speculation or inconvenience isn’t enough.

2) Safety still matters: employers have legal duties

Employers must take every precaution reasonable in the circumstances to protect workers’ health and safety. In safety-sensitive work (e.g., driving, operating machinery), impairment can create unacceptable risk and justify stricter rules and quicker action.

3) “Zero tolerance” vs. human rights: policies must be carefully designed

Human rights guidance in Ontario is clear:

• The purpose of any drug/alcohol rule should be workplace safety and impairment control, not moral policing.

• Policies should avoid automatic penalties after a positive test and build in accommodation (e.g., assessment, treatment options) where addiction is involved.

• Testing should be limited (for-cause, post-incident, or post-reinstatement) and part of a larger assessment by qualified professionals.

• Policies that conflate casual use with addiction risk discrimination (including on the basis of perceived disability).

4) Can employers test for drugs or alcohol?

The Ontario approach in a nutshell

• Alcohol testing (e.g., breathalyzer) can measure current impairment; drug tests often show past use, not present impairment—so automatic discipline based solely on a positive drug result is problematic.

• Random testing is exceptional. The Supreme Court of Canada held that random alcohol testing in dangerous workplaces generally requires evidence of a real substance problem in that workplace; otherwise it’s unreasonable.

• Ontario’s leading case (Entrop v. Imperial Oil) says random alcohol testing in some safety-sensitive contexts may be justifiable if sanctions are individualized, but random drug testing (that doesn’t show impairment) is far harder to justify.

Cannabis and prescription drugs

Employers can prohibit impairment at work (including from medically authorized cannabis) and may need medical information confirming fitness for duty, especially in safety-sensitive jobs. The duty to accommodate applies to medical cannabis use and to cannabis addiction, but not to recreational cannabis.

5) What real cases tell us

• Stewart v. Elk Valley Coal (SCC, 2017): The Court upheld the termination of a safety-sensitive worker who breached a clear “disclose-before-incident” policy and tested positive after an accident. Addiction was a protected disability, but the dismissal was for policy breach, not for the disability itself. This case underscores that well-crafted, safety-focused policies can be enforceable.

• Irving Pulp & Paper (SCC, 2013): A random alcohol testing program at a dangerous mill was struck down because the employer hadn’t shown a general alcohol problem at the workplace. Random testing isn’t a free pass; it needs strong justification.

• Entrop v. Imperial Oil (ONCA, 2000): Confirmed addiction is a disability. Found parts of a strict policy discriminatory; indicated random alcohol testing might be justifiable in safety-sensitive roles with individualized consequences, while drug testing that doesn’t show impairment is much harder to defend.

6) So… can you be dismissed for taking drugs at work?

Yes—sometimes. Here’s how it typically plays out:

• Safety-sensitive roles (e.g., drivers, operators): Showing up impaired or using at work may justify immediate suspension and, in serious cases, just-cause dismissal—but the employer must still inquire about possible addiction and consider accommodation before deciding on termination. Persistent impairment or refusal to participate in accommodation can end the duty to accommodate.

• Non-safety-sensitive roles: Discipline is still possible for breach of policy or performance issues, but automatic dismissal—especially where addiction is in play—can be discriminatory if the employer hasn’t explored accommodation (EAP referral, medical leave, modified duties, a last-chance agreement, etc.).

• Addiction vs. recreational use: If misconduct flows from an addiction disability, the employer must accommodate to undue hardship. If it’s purely recreational (no disability), human rights protections don’t apply—standard discipline may stand.

• Medical cannabis or prescribed medication: The employer must accommodate legal, medically-authorized use (e.g., scheduling doses, modified work) so long as you can perform essential duties safely; impairment on the job can still be restricted.

7) Practical tips

For employees

• If you struggle with substance use, consider seeking help before an incident. Ask about EAP or accommodation. Employers have a duty to inquire when disability may be affecting performance.

• Disclose restrictions, not diagnoses. Provide functional information (limitations, safety concerns) your employer needs to accommodate you.

• Follow treatment/return-to-work plans. Non-compliance can end the accommodation duty and support dismissal.

For employers

• Put safety first—but build in accommodation. Avoid automatic termination clauses; require individualized assessment after any positive test.

• Use testing sparingly (for-cause, post-incident, post-reinstatement). If considering random testing, gather evidence of a workplace problem and focus on impairment, not mere presence.

• Document the process: your duty to inquire, steps taken to accommodate, and why further accommodation would cause undue hardship (cost, funding, health & safety).

Key takeaways

• Addiction = disability → triggers a duty to accommodate up to undue hardship. Recreational use isn’t protected.

• Employers can ban impairment at work and must protect health & safety—especially in safety-sensitive jobs.

• Automatic firing for a positive test (without assessment/accommodation) risks discrimination.

• Random testing is the exception, not the rule; it needs strong workplace-specific justification.

• Well-crafted, safety-driven policies with real accommodation can be enforced—even upheld by the Supreme Court.

Need advice tailored to your situation?

Every case turns on specific facts—your job, policies, medical context, and what happened after the incident. Vanguard Law advises both employees and employers across Ontario on impairment, addiction, discipline, and dismissal.

Get in touch for confidential, practical guidance.

This post provides general information, not legal advice.