The Burlington Fire Marshal says a fire in an apartment building in the Vermont city was caused by smoking materials that were improperly disposed of. The fire in a six-unit apartment building at the corner of Murray and North streets was reported just after 11:30 p.m. Sunday. The fire in a six-unit apartment building at the corner of Murray and North streets was reported just after 11:30 p.m. Sunday. Firefighters saw flames in a second floor window and found heavy black smoke on the second floor.