A United Airlines flight was delayed for four hours after a passenger smoked pot in the first class lavatory, prompting the pilot to refuse to operate the flight for fear of failing a drug test due to the second-hand smoke.

Pot Smoker Grounds United Flight—Pilot Refuses To Risk Drug Test

View From The Wing flags an incident that occurred on a United flight at San Francisco International Airport.

First our flight was delayed due to technical issues, then waiting for the paperwork to get completed someone smoked weed in the front bathrooms. They got removed from the flight then sat on the plane for 40ish minutes waiting for crew to figure out what to do. Crew was concerned they got exposed so we deplaned and are awaiting new crew.

Quote from the captain, “I have 30 years left of my career at United, I’m not willing to risk getting drug tested when I get to Houston.”

Currently sitting in the terminal at SFO, no sign of a new crew yet. Original departure 8:50 am, current estimated departure 12:30 pm. Given a $15 meal voucher and they have rolled out a snack cart at the gate.

The passenger added that this was onboard UA1679, which was a flight from San Francisco (SFO) to Cancun (CUN). You can see the pilot mentions Houston above (which first made me think this occurred on UA1687 from San Francisco to Houston), but I figure the crew probably had a SFO-CUN-IAH routing, meaning they’d end the day and have to re-enter the USA at Bush Intercontinental Airport in Houston.

UA1679 was indeed delayed on Tuesday, August 5, 2025:

I don’t think it’s likely or even conceivable that a random drug test would have found THC in his system: the aircraft is well-ventilated. Even so, I cannot blame him…and I may have done the same thing. That’s because both the airline and the Federal Aviation Administration take a “zero tolerance” policy to drugs. Even trace amounts can torpedo a career. So when the captain said, “I have 30 years left of my career at United, I’m not willing to risk getting drug tested when I get to Houston,” he was not joking.

I hope the passenger who had the bright idea to smoke weed in the lavatory is hit with a bill for the delay (including the $15 meal vouchers each passenger received that get you almost nothing in SFO).

CONCLUSION

A captain erred on the side of caution by refusing to operate an international flight after he was exposed to secondhand smoke by a dullard smoking weed in the lavatory. While the captain may have been too cautious, one can hardly blame him in an environment in which there is no tolerance for even trace amounts of controlled substances.