But after three crews wearing breathing apparatus searched the premises in Albany Court, Chorley in the early hours of today, no-one was found.
The alarm was raised at around 1.30am.
A fire brigade spokesman said: “Three fire engines and crews (two from Chorley and one from Bolton) responded to a report that someone may be trapped in a fire in a flat.
“Firefighters equipped with breathing apparatus searched the prmeises, but no-one was trapped and there were no casualties.”