Marijuana Legalization and Impact on the Workplace


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Off-the-job cannabis use is not positively associated with elevated rates of occupational accidents or injuries

  • “We performed a cross-sectional analysis of the Canadian Community Health Survey (2013-16) of working individuals. We used multiple logistic regression modelling to calculate the odds of experiencing a work-related injury (defined as non-repetitive strain injury) among workers who reported using cannabis more than once during the prior 12 months as compared to non-users. … We found no association between past-year cannabis use and work-related injury. The association was unchanged in the subgroup analysis limited to high injury risk occupational groups.”
  • “Although it is common for organizations to screen employees and applicants for substances including cannabis and for politicians and societal leaders to make sweeping claims about cannabis, there is virtually no empirical research exploring cannabis use in relation to the modern workplace. … To address this gap in organizational and societal knowledge, we proposed a temporal-based cannabis framework that predicts relationships between three different forms of cannabis use (before, during, and after work) and five forms of workplace performance. … [C]ontrary to commonly held assumptions, not all forms of cannabis use harmed performance. In fact, after-work cannabis use did not relate to any of the workplace performance dimensions. This finding casts doubt on some stereotypes of cannabis users and suggests a need for further methodological and theoretical development in the field of substance use.”
  • “This systematic review investigates the potential link between cannabis use and occupational injury. Consequently, it appraises all available current literature from five databases. … The current body of evidence does not provide sufficient evidence to support the position that cannabis users are at increased risk of occupational injury.”
  • “We study the effect of state medical marijuana laws (MMLs) on workers’ compensation (WC) claiming among adults. … We use data on claiming drawn from the Annual Social and Economic supplement to the Current Population Survey over the period 1989 to 2012, coupled with a differences‐in‐differences design to provide the first evidence on this relationship. Our estimates show that, post MML, WC claiming declines, both the propensity to claim and the level of income from WC. These findings suggest that medical marijuana can allow workers to better manage symptoms associated with workplace injuries and illnesses and, in turn, reduce need for WC.”
  • “Legalizing medical marijuana was associated with a 19.5% reduction in the expected number of workplace fatalities among workers aged 25-44. … The association between legalizing medical marijuana and workplace fatalities among workers aged 25-44 grew stronger over time. Five years after coming into effect, MMLs were associated with a 33.7% reduction in the expected number of workplace fatalities. MMLs that listed pain as a qualifying condition or allowed collective cultivation were associated with larger reductions in fatalities among workers aged 25-44 than those that did not. … The results provide evidence that legalizing medical marijuana improved workplace safety for workers aged 25-44.”
  • “There is no or insufficient evidence to support … a statistical association between cannabis use and … occupational accidents or injuries.”
  • “Many factors contribute to occupational injuries. However, these factors have been compartmentalized and isolated in most studies. [This study] examined the relationship between work-related injuries and multiple occupational and non-occupational factors among construction workers in the USA.… [Among non-occupational factors associated with workplace accidents, being] obese/overweight, smoking, and cocaine use were risk factors for work-related injuries; however, drinking and marijuana use were not significant [factors].
  • Employees who test positive for marijuana in workplace drug tests are no more likely to be involved in occupational accidents as compared to those who test negative. “This study fell short of finding an association between marijuana use and involvement of workplace accidents. … This study cannot be taken as definitive evidence of absence of an association between marijuana and work related accidents but the findings are compelling.”
  • “[I]t is not clear that heavy cannabis users represent a meaningful job safety risk unless using before work or on the job; urine tests have poor validity and low sensitivity to detect employees who represent a safety risk; … [and] urinalysis has not been shown to have a meaningful impact on job injury/accident rates.”

Liberalized marijuana laws are associated greater labor participation, lower rates of absenteeism, and higher wages