Research Summaries and Guidance

OEMAC Position Statement on the Implications of Cannabis Use for Safety‑Sensitive and Decision‑Critical Work

This OEMAC position statement addresses the implications of cannabis use for individuals in safety-sensitive and decision-critical occupations. It aims to guide workplace safety policy and occupational health decisions amid growing cannabis use and legalization in Canada.

Download the Research Summary

CoRE Insights

  1. Cannabis Causes Prolonged Impairment: Cannabis impairs cognitive, motor, and psychological functions through intoxication, residual effects, withdrawal, and chronic use. These effects can persist long after consumption, especially with frequent or high-dose use, posing safety risks even when intoxication is not obvious.
  2. Research Seldom Reflects Real-World Use: Most studies use low THC doses and controlled conditions that don’t mirror the high-potency, frequent-use patterns that may be more common in real-world settings. This limits their applicability for workplace safety decisions.
  3. A Precautionary Approach Is Warranted: Due to ongoing uncertainty about impairment duration and variability across individuals, OEMAC recommends a cautious, risk-based approach. Abstaining from safety-sensitive or decision-critical work for at least 24 hours post-use and updating workplace policies are key interim safeguards. 

Research Overview

The statement is based on a comprehensive review of national and international literature, policy statements, and clinical guidelines from bodies such as OEMAC, and the Canadian Society of Addiction Medicine. It synthesizes evidence from peer-reviewed studies on cannabis pharmacology, patterns of impairment, workplace risk, and occupational medicine. The review considered diverse aspects of cannabis use, including THC concentration, consumption methods, frequency of use, individual variability, and co-use with other substances.

Key Findings

Cannabis can impair cognitive and motor function through intoxication, residual effects, withdrawal, and chronic use, often beyond the immediate period of consumption. The variability in individual responses and cannabis products complicates detection and risk assessment. Most studies don’t reflect real-world use, limiting their relevance. Given these uncertainties, a precautionary, risk-mitigation approach is justified for safety-sensitive and decision-critical work. 

  • Impairment can result from intoxication, residual effects, withdrawal, or chronic use—even in the absence of obvious signs. 
  • Individual variability and product differences (e.g., THC content) make impairment unpredictable and hard to assess. 
  • Most studies use low doses and controlled conditions, failing to reflect real-world workplace use patterns. 
  • Given these limitations, a precautionary approach is warranted, prioritizing safety in high-risk occupational settings. 

How to Take Action

  • Adopt a minimum 24-hour waiting period after cannabis use before returning to safety-sensitive or decision-critical tasks. 
  • Update workplace drug and alcohol policies to reflect cannabis-specific risks and timelines. 
  • Apply the precautionary principle in occupational settings, especially where empirical evidence is lacking but risk is present. 
  • Provide employer and employee education on the risks of impairment and resources for substance use support. 
  • Encourage research that simulates real-world cannabis use (high doses, repeated use) and includes diverse cannabinoid profiles. 
  • Develop validated tools for impairment detection beyond standard toxicological testing. 
  • Promote interdisciplinary dialogue to guide evolving HR and safety policies in light of cannabis legalization. 

Links to Research Materials

OEMAC Position Statement on the Implications of Cannabis Use for Safety‑Sensitive and Decision‑Critical Work 

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