Health effects of exposure to second and third hand marijuana smoke: a systematic review CMAJ Open Secondhand exposure from vaping marijuana: Concentrations, emissions, and exposures determined using both research grade and low cost monitors ScienceDirect Secondhand marijuana smoke can cause range of detectable effects, study finds Hub Even if an employee only uses marijuana on the weekends, it could still show up on their workplace sponsored drug screen the following week or later. According to some estimates, traces of THC Secondhand Vape Exposure: Effects, Who's at Risk, and More