We ran a research study where we exposed people to second-hand cannabis smoke under different conditions. One was a ventilated room environment, and one was an unventilated environment, and then within the unventilated environment we varied the potency of the cannabis that people were smoking. We found a substantial impact of room ventilation on the amount of exposure.
In terms of drug testing, whether someone would test positive or not after exposure depended on how we were testing and what cut-offs were used, but we did find that in an unventilated environment positive tests would be possible for both urine and blood, as well as saliva or oral fluid. The duration when you could be positive depended on how you were tested and what cut-off was used.
Becoming positive under those circumstances was really limited to the unventilated environment, where the room air was dense with smoke. When the air conditioning or the HVAC system was turned on, people were not impaired and generally tested negative.
Second-hand smoke exposure is a real concern. It's a real thing, but it's hard to be impacted by that unknowingly. Indoor second-hand smoke regulations are appropriate, the same way they are for tobacco use. We have not done the parallel study with vaporization, so we don't really know the level of second-hand exposure with vaped cannabis versus smoked. Then there are obvious limitations beyond that. For the study we did, we exposed people for one hour, one time. That doesn't tell us anything about what happens if they are exposed for a longer period of time, or a shorter period of time but repeatedly. Again, this is an area where more science is needed, but our study demonstrated that you can get a slight intoxication and test positive in an extreme exposure environment.