Can passive inhalation of marijuana cause a false positive drug test?
Sometimes employees who test positive for marijuana will claim it was the result of passive inhalation – “I was at a party last night and other people were smoking dope, not me. But I think I inhaled some of the smoke.” The likelihood that an individual would inhale enough marijuana smoke to produce a positive drug test result at the cutoff levels currently observed by most drug testing labs (50 ng/mL) is virtually nonexistent.
Sometimes people who test positive for marijuana will claim it was the result of passive inhalation. Available research show that an individual must have been in an confined space, such as an automobile, for a period of time in order for detectable levels of THC-delta 9 to be found in oral fluid. Any potential effect is also of short (45min-one hour) duration. Thus, claims of passive inhalation “over the weekend” or even “last night”, would not cause a non-negative on-site test result.
