Marijuana is currently legal for medicinal use in 33 states and for recreational use in 10 states, plus the District of Columbia, Guam and Puerto Rico. The changes in laws have brought with them a change in public attitude, as well, with a Pew Research Center survey showing that 62 percent of Americans are in favor of the drug’s legalization. In addition, a 2016 Gallop poll has demonstrated a rise in its use, with 13 percent of U.S. adults using marijuana. Even so, it remains illegal under federal law, causing confusion for employers and safety professionals. Impairment is a big concern in safety-sensitive positions, which can last from hours to weeks, according to certain studies, but even if blood levels do show THC in the system, impairment cannot be an automatic assumption. Although employers are required to make accommodations for employees’ medical use, it is important to communicate clear drug policies.