While the number of workers testing positive for use of opiates, heroin and cocaine has declined, positive tests for marijuana use are on the upswing—even for those in “safety-sensitive” occupations such as truck drivers and construction workers.

Indeed, due to the rise in marijuana use, the rate of workforce drug positivity hit a 14-year high in 2018, logging in at 4.4 percent, according to the latest Quest Diagnostics Drug Testing Index.