In State v. Leech, 114 Wn.2d 700, 790 P.2d 160 (1990), the defendant was convicted of the felony murder of a fire fighter who died of carbon monoxide poisoning while fighting a fire that was caused by the defendant. The defendant argued that the evidence was insufficient to prove that his act of committing arson was the proximate cause of the fire fighter's death because the fire fighter negligently allowed his breathing apparatus to run out of oxygen. In holding that the arson fire was the proximate cause of the fire fighter's death, the Court held: "that the fire fighter's alleged negligence in using his breathing apparatus was not the sole cause of his death. Since his failure to use the apparatus would not have killed him had the defendant not set the arson fire, the defendant's conduct in setting the fire was a proximate cause of the fire fighter's death." Leech, 114 Wn.2d at 705.