Firefighters were called to a sandwich shop in Accrington after some laundry caught fire.
The fire is believed to have started after a cigarette was accidentally dropped into a plastic laundry basket.
Three flats adjacent to The Butty Box on Abbey Street had to be evacuated because of smoke.
The incident happened at around 8pm on Thursday, November 3 and the shop was shut at the time.
The fire cause heavy smoke damage to the shop and light smoke damage to the flats.
Butty Box co-owner Cheryl Denwood said: "I have no idea what happened. I just got a call at 8pm saying there was a fire.
"Earlier in the day I took some towels to the laundrette to get washed and dried and I asked somebody to pick them up as I was busy. They brought it back and we stuck it on top of the fridge. None of us smoke.
"I was here on Friday at 7am to begin the clean up but I have good customers and friends who helped me and we were open by 11am."