Firefighters extinguished a small fire in a second floor bathroom of a duplex at 40 Lake St. yesterday afternoon.

A plumber working on some copper fittings inadvertently let some fire get into a chase and notified the Fire Department at 1:45 p.m. Firefighters were on scene for about a half hour, opening up walls and the ceiling leading to the third floor to make sure no flames had extended. None had.