The most destructive year in San Francisco’s drug epidemic has ended with 806 people dead from accidental overdoses. About 8 in 10 of those deaths involved fentanyl, the cheap and potent synthetic opioid. The previous record of 726, set in 2020, followed the COVID-19 outbreak. Overdose deaths in the city had been rising, with an alarming uptick in 2018 as fentanyl became increasingly available.