Research Paper
Medical marijuana laws and workplace fatalities in the United States

https://doi.org/10.1016/j.drugpo.2018.07.008Get rights and content

Abstract

Aims

The aim of this research was to determine the association between legalizing medical marijuana and workplace fatalities.

Design

Repeated cross-sectional data on workplace fatalities at the state-year level were analyzed using a multivariate Poisson regression.

Setting

To date, 29 states and the District of Columbia have legalized the use of marijuana for medicinal purposes. Although there is increasing concern that legalizing medical marijuana will make workplaces more dangerous, little is known about the relationship between medical marijuana laws (MMLs) and workplace fatalities.

Participants

All 50 states and the District of Columbia for the period 1992–2015.

Measurements

Workplace fatalities by state and year were obtained from the Bureau of Labor Statistics. Regression models were adjusted for state demographics, the unemployment rate, state fixed effects, and year fixed effects.

Findings

Legalizing medical marijuana was associated with a 19.5% reduction in the expected number of workplace fatalities among workers aged 25–44 (incident rate ratio [IRR], 0.805; 95% CI, .662–.979). The association between legalizing medical marijuana and workplace fatalities among workers aged 16–24, although negative, was not statistically significant at conventional levels. 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 (IRR, 0.663; 95% CI, .482–.912). 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.

Conclusions

The results provide evidence that legalizing medical marijuana improved workplace safety for workers aged 25–44. Further investigation is required to determine whether this result is attributable to reductions in the consumption of alcohol and other substances that impair cognitive function, memory, and motor skills.

Introduction

Although marijuana remains illegal under federal law, 29 states and the District of Columbia have passed laws legalizing its use for medicinal purposes (State Medical Marijuana Laws, 2017). Medical marijuana laws (hereafter MMLs) remove state-level penalties for using and possessing marijuana for medical purposes. Patients are required to obtain approval or certification from a physician, and physicians who recommend marijuana to their patients are immune from criminal prosecution.

Increasingly, concerns are being raised over the potential impact of MMLs on workplace safety (Goldsmith et al., 2015; Parnes, Bravo, Conner, & Pearson, 2018; Phillips et al., 2015; Schwartz, 2017). As a backdrop to these concerns, there are important legal issues surrounding workplace safety and the use of medical marijuana that remain unresolved. For instance, in many states it is unclear whether employers can impose sanctions on registered medical marijuana patients who test positive for tetrahydrocannabinol (the psychoactive component in marijuana), or whether insurance companies can claim marijuana as the cause of injury or death in the workplace (Deitchler, 2015; Hickox, 2012; Olafson, 2016).

There is strong evidence that legalizing medical marijuana leads to a decrease in the price of marijuana and an increase in its consumption, presumably due to diversion from the medical to the recreational market (Anderson, Hansen, & Rees, 2013; Chu, 2014, 2015). However, the association between legalization and workplace safety could, in theory, be negative or positive. On the one hand, extensive research has demonstrated that there are important short-term effects of marijuana use on psychomotor performance and cognition that could lead to more on-the-job accidents, including impairments in memory function, information processing, hand-eye coordination, and reaction times (Hall, 2009; Hartman & Huestis, 2013; Marijuana, 2017; Ramaekers, Berghaus, van Laar, & Drummer, 2004). On the other hand, previous studies have found that the legalization of medical marijuana leads to substantial reductions in the consumption of alcohol, opioids and other substances, (Anderson et al., 2013; Bachhuber, Saloner, Cunningham, & Barry, 2014; Bradford & Bradford, 2016; Reiman, 2009; Sabia, Swigert, & Young, 2017), which could lead to safer workplaces and fewer accidents.

Drawing on data at the state-year level collected by the Bureau of Labor Statistics for the period 1992–2015, the relationship between legalizing medical marijuana and workplace fatalities was examined. Multivariate Poisson regression analysis was used to adjust for demographics, income, the unemployment rate, legalization of recreational marijuana, decriminalization of marijuana, state fixed effects, and year fixed effects. No previously published study has examined the relationship between MMLs and workplace fatalities.

Section snippets

Methods

Panel data on workplace fatalities at the state-year level came from Census of Fatal Occupational Injuries (CFOI). These data are produced by the Occupational Safety and Health Statistics (OSHS) program, which is administered by the Bureau of Labor Statistics (BLS). The CFOI provides counts of all fatal work injuries occurring in the U.S. during each calendar year. The OSHS program uses diverse state, federal, and independent data sources to identify, verify, and describe fatal work injuries,

Results

The association between legalizing medical marijuana and total workplace fatalities, although negative, was not statistically significant at conventional levels (Table 3). By contrast, legalizing medical marijuana was associated with a 19.5% reduction in the expected number of workplace fatalities among workers aged 25–44 (IRR, 0.805; 95% CI, .662–.979) after adjusting for the covariates listed in Table 2, state fixed effects, and year fixed effects. This negative association was robust to

Discussion

MMLs protect patients from criminal prosecution for smoking marijuana and for consuming it in oils, pills, and edibles. However, the use of medical marijuana in the workplace is generally not protected. Several states (e.g., Colorado, Michigan, Oregon, Washington) have ruled that employers may discipline employees or terminate their employment following a positive drug test because MMLs are not intended to address employment issues (Deitchler, 2015; Hickox, 2012). Although some MMLs explicitly

Conclusion

Although 29 states and the District of Columbia have passed laws legalizing marijuana for medicinal use, there is a dearth of evidence on the relationship between medical marijuana and workplace safety. The current study is the first to explore the effects of medical marijuana laws on workplace fatalities. Our results suggest that legalizing medical marijuana leads to a reduction in workplace fatalities among workers aged 25–44. This reduction may be the result of workers substituting marijuana

Conflict of interest disclosures

None reported.

Funding/Support

Partial support for this research came from a Eunice Kennedy Shriver National Institute of Child Health and Human Development research infrastructure grant, R24 HD042828 to the Center for Studies in Demography and Ecology at the University of Washington.

Role of the Funder/Sponsor

The funder had no role in the design and conduct of the study; collection, management, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Author contributions

Drs. Anderson and Rees had full access to the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Anderson, Rees, Tekin.

Acquisition, analysis, or interpretation of data: Anderson, Rees.

Drafting of the manuscript: Anderson, Rees, Tekin.

Critical revision of the manuscript for important intellectual content: Anderson, Rees, Tekin.

Statistical analysis: Anderson.

Obtained funding: Anderson.

Administrative, technical,

References (52)

  • D.M. Anderson et al.

    Medical marijuana laws and teen marijuana use

    American Law and Economics Review

    (2015)
  • D.M. Anderson et al.

    Medical marijuana laws and suicides by gender and age

    American Journal of Public Health

    (2014)
  • M. Asbridge et al.

    Acute cannabis consumption and motor vehicle collision risk: Systematic review of observational studies and meta-analysis

    BMJ

    (2012)
  • M.A. Bachhuber et al.

    Medical cannabis laws and opioid analgesic overdose mortality in the United States, 1999–2010

    JAMA Internal Medicine

    (2014)
  • M. Bertrand et al.

    How much should we trust differences-in-differences estimates?

    The Quarterly Journal of Economics

    (2004)
  • A.C. Bradford et al.

    Medical marijuana laws reduce prescription medication use in Medicare Part D

    Health Affairs

    (2016)
  • A.C. Cameron et al.

    Regression analysis of count data

    (2018)
  • Census of Fatal Occupational Injuries Summary

    Bureau of labor statistics, United States Department of Labor

    (2015)
  • Y. Chu

    Do medical marijuana laws increase hard-drug use?

    The Journal of Law & Economics

    (2015)
  • D.L. Deitchler

    The workplace and medical marijuana: Employer guidelines for navigating the legal haze

    (2015)
  • R.S. Goldsmith et al.

    Medical marijuana in the workplace challenges and management options for occupational physicians

    Journal of Occupational and Environmental Medicine

    (2015)
  • R.L. Hartman et al.

    Cannabis effects on driving skills

    Clinical Chemistry

    (2013)
  • S.A. Hickox

    Drug testing of medical marijuana users in the workplace: An inaccurate test of impairment

    Hofstra Lab & Emp LJ

    (2012)
  • Local area unemployment statistics

    Bureau of labor statistics, United States Department of Labor

    (2018)
  • S.D. Lynne-Landsman et al.

    Effects of state medical marijuana laws on adolescent marijuana use

    American Journal of Public Health

    (2013)
  • Marijuana

    National Institute on drug abuse

    (2017)
  • Cited by (24)

    • Sex, marijuana and baby booms

      2020, Journal of Health Economics
      Citation Excerpt :

      Table 1 shows dates of when the laws first became effective, as well important heterogeneity in the laws including whether the state allows home cultivation, the date when the first dispensary or compassionate treatment center opened, and whether medical marijuana can be prescribed for non-specific pain symptoms. Frequently there is a lag between when a law becomes effective in a state and when legally supplied marijuana becomes available (e.g., Choi et al., 2016; Anderson et al., 2018; Powell et al., 2018).9 Table 1 defines “First Legal Supply” as the earliest date marijuana becomes available through legal means, such as through an operational dispensary or legalized home cultivation.

    • The Public Health Effects of Legalizing Marijuana

      2023, Journal of Economic Literature
    View all citing articles on Scopus
    View full text