--- title: "Can you fail a hair drug test from secondhand smoke" description: "Can you fail a hair drug test from secondhand smoke? Learn the facts on passive exposure and hair testing accuracy. Contact AMH Nationwide. Call (877) 731-6362." author: "AMH Nationwide" date: "2026-08-28" tags: ["can you fail a hair drug test from secondhand smoke"] canonical: "https://amhnationwide.com/can-you-fail-a-hair-drug-test-from-secondhand-smoke/" last_updated: "2026-08-28" --- # Can you fail a hair drug test from secondhand smoke **By AMH Nationwide** | August 28, 2026 Can you fail a hair drug test from secondhand smoke? Learn the facts on passive exposure and hair testing accuracy. Contact AMH Nationwide. Call (877) 731-6362. --- Can you fail a hair drug test from secondhand smoke? Hair drug tests are designed to detect active drug use, not casual or environmental exposure such as secondhand smoke. Passive exposure alone rarely causes a positive hair test result. For questions or testing, call (877) 731-6362. BASICS ## What is a hair drug test and how does it work? A hair drug test analyzes a small sample of hair to detect drug metabolites deposited in the hair shaft from bloodstream exposure. It typically covers drug use over the past 90 days, depending on hair length. Hair testing is often used by employers, courts, and [probation](https://amhnationwide.com/hair-follicle-drug-test-probation/) agencies due to its longer [detection window](https://amhnationwide.com/hair-follicle-drug-test-detection-window/) compared to [urine](https://amhnationwide.com/urine-drug-testing/) or saliva tests. The test is performed by one of five national lab networks: [Quest Diagnostics](https://www.questdiagnostics.com/), [LabCorp](https://www.labcorp.com/), Omega Labs, United States Drug Testing Labs, or ExperTox. AMH Nationwide facilitates lab orders and directs individuals to nearby collection sites for sample collection. EXPOSURE ## Can secondhand smoke cause a positive hair drug test? Secondhand smoke exposure is generally insufficient to cause a positive hair drug test. Hair testing detects drug metabolites incorporated internally from the bloodstream, not just external contamination. Passive environmental exposure typically does not result in enough metabolite concentration within hair to trigger a positive result. Hair drug tests detect internal metabolites, not surface contamination. Secondhand smoke rarely delivers enough drug to bloodstream to affect hair. Certified labs use washing procedures to remove external contaminants before analysis. LAB PROCEDURE ## How do labs prevent false positives from environmental contamination? Labs follow strict protocols to minimize false positives from external contamination. Hair samples undergo washing steps to remove surface contaminants such as smoke residue or dust. Only metabolites incorporated inside the hair shaft from the bloodstream are measured. Additionally, all non-negative hair drug test results are reviewed by a certified Medical Review Officer (MRO). The MRO evaluates potential alternative explanations, including environmental exposure, before confirming a positive result. DETECTION WINDOW ## What is the detection window for hair drug tests compared to other tests? Hair drug tests typically detect drug use within the past 90 days, depending on hair length. This is longer than urine tests (1-4 days for most drugs) and saliva tests (up to 48 hours). Hair testing is less affected by short-term exposure and is designed to confirm repeated or chronic drug use. | Test Type | Typical Detection Window | | --- | --- | | Hair Drug Test | Up to 90 days | | Urine Drug Test | 1-4 days | | Saliva Drug Test | Up to 48 hours | ## Need Accurate Hair Drug Testing? Contact AMH Nationwide to arrange hair drug testing with certified labs and expert Medical Review Officer analysis. Call (877) 731-6362. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) DOT REGULATIONS ## Is hair testing allowed for DOT-regulated safety-sensitive positions? No. The Department of Transportation (DOT) requires federally certified urine drug testing under [49 CFR Part 40](https://www.transportation.gov/odapc/part40) for safety-sensitive positions. Hair testing is not accepted for DOT-regulated roles but may be used for non-DOT employment or other purposes. ORDERING ## How do I get a hair drug test through AMH Nationwide? AMH Nationwide provides lab orders for hair drug testing and directs individuals to one of over 20,000 collection sites nationwide. There is no online ordering available. To schedule or inquire about hair drug testing, call (877) 731-6362. Pricing varies by test panel and detection window. AMH Reviewed & Maintained By AMH Nationwide Customer Service AMH Nationwide is BBB A+ accredited and routes every order through Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox, all of which use multiple lab certification agencies and standards such as [SAMHSA](https://www.samhsa.gov/workplace/drug-testing)-aligned laboratory protocols, the ANSI National Accreditation Board for forensic testing and calibration, the College of American Pathologists (CAP), and Clinical Laboratory Improvement Amendments (CLIA). Every non-negative screen is reviewed by a certified Medical Review Officer as part of standard processing before a result is released, and chain-of-custody documentation is maintained on every collection. This page does not constitute medical or legal advice. **Last updated:** July 2026 You May Also Need [Nail Drug TestingNo head or body hair available? A 5-panel fingernail test covers a similar look-back window.Learn more →](https://amhnationwide.com/5-panel-fingernail-drug-test/)[ChildGuard: Environmental ExposureConcerned about a child or loved one? ChildGuard screens for exposure to drugs in their environment.Learn more →](https://amhnationwide.com/5-panel-hair-drug-test-environmental-exposure-childguard/)[Shorten the Detection WindowShortened options like 30 and 60 day hair panels are also available, useful when a urine test’s 1-3 day window is too short.Learn more →](https://amhnationwide.com/30-day-hair-drug-test/)[Hair ETG Alcohol TestAlso need alcohol testing? The hair ETG test screens for alcohol use, and can be added to the same collection.Learn more →](https://amhnationwide.com/etg-and-peth/) Frequently Asked Questions ## Common Questions It is highly unlikely. Hair tests detect metabolites from drug use incorporated internally. Passive marijuana smoke exposure rarely delivers enough drug to bloodstream to cause a positive hair drug test. Yes. Laboratories wash hair samples to remove external contaminants like smoke or dirt. This reduces the chance of false positives from environmental exposure. Hair drug tests typically detect drug use up to 90 days prior, depending on hair length. This makes it suitable for detecting repeated or chronic use. Hair testing is more reliable for detecting repeated drug use. One-time or very infrequent use may be below detection thresholds, especially if hair length is short. No. Hair testing is accepted for many employers and courts but is not accepted for DOT-regulated safety-sensitive roles, which require federally certified urine testing. Call AMH Nationwide at (877) 731-6362 to receive a lab order and find a nearby collection site. AMH does not offer online ordering. Sources • [SAMHSA – Mandatory Guidelines for Federal Workplace Drug Testing Programs](https://www.samhsa.gov/workplace/drug-testing) • [U.S. DOT – 49 CFR Part 40 – Procedures for Transportation Workplace Drug and Alcohol Testing Programs](https://www.transportation.gov/odapc/part40) • [CDC – National Center for Health Statistics – Drug Use FastStats](https://www.cdc.gov/nchs/fastats/drug-use.htm) • [Quest Diagnostics – Employer Solutions, Hair Testing Methodology](https://www.questdiagnostics.com/) • [LabCorp – Occupational Testing Services](https://www.labcorp.com/) ## Ready to get started? AMH Nationwide provides the lab order and arranges collection nationwide. Every non-negative result reviewed by a certified Medical Review Officer. Call (877) 731-6362 or contact us. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) --- **Need a drug, alcohol, HIV or STD test?** AMH Nationwide is a national lab testing agency operating since 2004, with more than 20,000 collection sites across the United States. Hair, urine, fingernail and blood testing, panels from 5 through 19, for individuals and employers. - Call: (877) 731-6377 - Find a collection site: https://amhnationwide.com/locations/ - Full page: https://amhnationwide.com/can-you-fail-a-hair-drug-test-from-secondhand-smoke/