[questioning_grl]

So my question is this. My roommates are chronic pot smokers. They smoke everyday and they smoke quite a bit everyday. I don't somke it but would inhaling second hand smoke make me come out positive on a hair drug test? Please advise.. . I have a test coming in about 2 weeks.

[mike2347]

No unless you're like sitting over top of their blunt. But realistically it takes less than 2 weeks for a novice to be clean

[DrBill100]

It isn't necessary to first inhale the smoke in order for smoked drugs and their metabolites to infuse into hair. SAMHSA warns of this in a recent publication.(1)

Many smoked substances enter your system and are incorporated into hair through sweat and sebaceous glands in abundance in the scalp. This is particularly true for cannabis smoke. (2)

This is a real and ongoing problem in hair drug testing (3) that has received adequate attention in research but is widely ignored by those performing or subjected to HDT.

The external contamination factor is exacerbated by the combination of sensitive instruments and low cutoffs paired with lack of uniformity and regulation of the washing techniques used from one lab to another.

Finally, there is the problem of THC resin that deposits on surfaces, furniture etc, and is transferred to hair by your hands.

From the standpoint of HDT continued and prolonged exposure to environmental side-stream smoke does pose a danger.


1) Substance Abuse and Mental Health Services Administration. (2012). Clinical drug testing in primary care. Technical Assistance Publication (TAP) 32. HHS Publication No. SMA 12-4668. Rockville, MD: Substance Abuse and Mental Health Services Administration, Chapter 3, p. 21

2) Volker Auwärter, Ariane Wohlfarth, et al (2010) Hair analysis for Δ9-tetrahydrocannabinolic acid A—New insights into the mechanism of drug incorporation of cannabinoids into hair. Forensic Science International, Vol. 196, No. 1-3. (20 March 2010), pp. 10-13

3) Marilyn A. Huestis (2007) Human Cannabinoid Pharmacokinetics. Chem Biodivers. 2007 August; 4(8): 1770–1804. Sec 3.5