Fire investigators say the improper disposal of a cigarette is likely what sparked a duplex fire this morning at 41 Marlborough Crescent.

They were called to the duplex just before 1 a.m. CST, and found the attic and half the building engulfed in flames.

Three people escaped without injuries. The damage is estimated at $100,000.

Battalion chief David Nahachewsky says this is the second time in a week that fire crews have been called to a fire, after smouldering ashes from a cigarette were mixed in with yard debris.