Emergency crews were on the scene of a one-alarm fire at a residential and commercial building after a cigarette was “carelessly discarded” in the city’s east end.

Toronto Fire responded to a call for the blaze in the area of Queen and Morse streets at around 3 p.m. on Tuesday.

Firefighters initially said “some form of explosion” occurred at the rear of the building, but it was not immediately clear what the explosion was.

Around 7 p.m., Toronto Fire confirmed the cause was smoking materials being thrown onto a deck, which subsequently caught fire.

Black smoke was visible in the immediate area.

No injuries were reported as a result of the fire.