An apparently false story about there being multiple cases of people "passing out" at 2018's 420 celebration on Hippie Hill due to fentanyl-laced pot was disseminated by both the SFPD and Supervisor Vallie Brown, but why?

SF Weekly tried to track down the truth to the story — which echoes multiple other similar stories around the country that Vice debunked in 2017 — and they came up with zero evidence that there were any fentanyl overdose or other fentanyl-related medical cases connected to 420 last year.

Park Station commanding officer Captain Una Bailey nonetheless put this misinformation in the station's April 18 newsletter:

One note of caution if you are attending the event please ensure you are buying your marijuana from a legal vendor. There will be no legal sale of marijuana in the event. Buying marijuana on the street and not from a legal vendor exposes you to marijuana that may be laced with other drugs. Last year we had numerous attendees pass out form using marijuana laced with fentanyl.

At a news conference on Friday, District 5 Supervisor Vallie Brown reiterated this, getting even more specific. Brown said that "a lot" of the black-market weed being sold at last year's 420 was laced with fentanyl, and cited "10 to 12 people" who were rushed out of the event by medical personnel because of overdoses.

CBS SF initially reported on Brown's warning about black-market cannabis laced with fentanyl, but then corrected its own story after speaking with San Francisco Health Officer Tomás J. Aragón. "I know that’s how it’s been reported, but I don’t think we know how people consumed, or got exposed to the opioids that they did," Aragón said.

The Department of Public Health told SF Weekly, in fact, that "there were no confirmed fentanyl overdoses at Hippie Hill on 420 in 2018." Nor were there any this year.

The Weekly also spoke with Eliza Wheeler of the Harm Reduction Coalition, who explained that it's actually not possible to overdose on fentanyl by smoking it mixed with weed — its low combustion point means that it's destroyed the minute it comes into contact with a flame.

The entire rumor appears clearly designed to frighten the public into avoiding black-market pot dealers, which may be wise anyway given whatever else weed can be laced with, and given our robust legal recreational pot retail offerings in SF.

But when Snopes has already called bullshit on a story, perhaps a police captain and a city supervisor should be doing better research.

Related: 4/20 Blankets Golden Gate Park With The Smoke Of 19,000 Stoners, Park Shockingly Clean On Sunday