Overview

• A United Airlines pilot on flight UA1679 from San Francisco to Cancun refused to operate the plane after a passenger smoked marijuana in an onboard lavatory.
• The crew deplaned all passengers, secured a replacement team and the flight resumed after a four-hour delay with travelers receiving $15 meal vouchers.
• Under FAA zero-tolerance rules any detectable marijuana metabolite in a crew member’s system triggers a failed drug test regardless of how exposure occurred.
• Aviation experts note that modern cabin ventilation and HEPA filtration make positive drug tests from secondhand smoke extremely rare.
• The incident has prompted widespread debate about the gap between strict drug-testing policies and the minimal actual risks of passive cannabis exposure.