title: Non-smoker exposure to secondhand cannabis smoke. I. Urine screening and confirmation results.
abstract: Increased cannabis potency has renewed concerns that secondhand exposure to cannabis smoke can produce positive drug tests. A systematic study was conducted of smoke exposure on drug-free participants. Six experienced cannabis users smoked cannabis cigarettes (5.3% THC in Session 1 and 11.3% THC in Sessions 2 and 3) in a sealed chamber. Six non-smokers were seated with smokers in an alternating manner. Sessions 1 and 2 were conducted with no ventilation and ventilation was employed in Session 3. Non-smoking participant specimens (collected 0-34 h) were analyzed with four immunoassays at different cutoff concentrations (20, 50, 75 and 100 ng/mL) and by GC-MS (LOQ = 0.75 ng/mL). No presumptive positives occurred for non-smokers at 100 and 75 ng/mL; a single positive occurred at 50 ng/mL; and multiple positives occurred at 20 ng/mL. Maximum THCCOOH concentrations by GC-MS for non-smokers ranged from 1.3 to 57.5 ng/mL. THCCOOH concentrations generally increased with THC potency, but room ventilation substantially reduced exposure levels. These results demonstrate that extreme cannabis smoke exposure can produce positive urine tests at commonly utilized cutoff concentrations. However, positive tests are likely to be rare, limited to the hours immediately post-exposure, and occur only under environmental circumstances where exposure is obvious.
authors.affiliation: Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, Baltimore, MD, USA edwardjcone@gmail.com.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Cone
authors.affiliation: Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: George E
authors.initials: GE
authors.lastname: Bigelow
authors.affiliation: Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Evan S
authors.initials: ES
authors.lastname: Herrmann
authors.affiliation: RTI International, Research Triangle Park, NC, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Mitchell
authors.affiliation: Division of Workplace Programs (DWP), Substance Abuse and Mental Health Services Administration (SAMHSA), Rockville, MD, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: LoDico
authors.affiliation: Division of Workplace Programs (DWP), Substance Abuse and Mental Health Services Administration (SAMHSA), Rockville, MD, USA.
authors.forename: Ronald
authors.initials: R
authors.lastname: Flegel
authors.affiliation: Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Vandrey
mesh_terms: D000328:Adult; D002188:Cannabis / Q000737:chemistry*; D013759:Dronabinol / Q000652:urine; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D012680:Sensitivity and Specificity; D012907:Smoking / Q000009:adverse effects*; D013048:Specimen Handling; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D016482:Urinalysis; D055815:Young Adult
chemical_list: D014028:Tobacco Smoke Pollution; D013759:Dronabinol