"We conclude that there is an association between substance use and occupational injury. This association is stronger for males and in certain industries, such as manufacturing and construction, and may also be stronger for younger workers, though future research is needed on this last point. The proportion of injuries caused by substance use, however, is relatively small. Instead, there is mounting evidence that harmful substance use is one of a constellation of behaviors exhibited by certain individuals who may avoid work-related safety precautions and take greater work-related risks. Thus, we suspect that it is more likely that risk-taking dispositions, often termed deviance proneness, and other omitted factors can explain most empirical associations between substance use and injuries at work."
Ramchand, Rajeev; Pomeroy, Amanda; Arkes, Jeremy, "The Effects of Substance Use on Workplace Injuries" Center for Health and Safety in the Workplace (Santa Monica, CA: RAND Corporation, 2009), p. 31.