VIDEO: When firefighters run into a burning building it isn't the flames that are most dangerous it's the smoke. The International Fire Association has deemed every house fire a hazardous material incident because of the increasing levels of hydrogen cyanide and carbon monoxide. “Right now cancer is the number one killer of firefighters in America,” said Curtis Dunn with the Firefighter Cancer Support Network. Dunn says firefighters are two times more likely to develop certain cancers. A statistic all too real for Green Bay Metro Fire Captain Todd Gurtz, “It was stage 4; it was in my pelvis and my lungs."