This was one of the biggest fires in San Francisco history, and it happened January 4, 1979 in Mid Market at Kaplans, 1055 Market
Kaplans was once a 6 story building, like many of the buildings on that stretch of Market street between 6th and 7th
6 alarms, and it was arson, and the whole building burned to the ground. The owners rebuilt one story and the same owners are still in business today as Kaplans Surplus and still get great reviews on yelp. There’s also some reference to the fire and Mid market of the era in this article in Poor magazine by Martha Bridegam
Kaplan’s today
Kaplans in 1975
San Francisco assessors evaluation 1975