Firefighters say discarded cigarettes left on a cardboard box started an apartment fire Thursday morning. Yakima fire crews responded to an alarm around 8:50 a.m. at the Beech Street Apartments and found a fire contained to a third floor deck of one of the units. Firefighters are crediting the sprinkler system from keeping the fire from spreading to the attic which could have caused major damage. They say a person living in the apartment had been smoking out on the deck and thought they had put the cigarette out, but later heard a loud pop and smoke coming from the sliding door at the deck. Firefighters want to remind people not to put out their cigarettes in planters as plant soil can ignite.