that there is a slightly higher risk when you look at the firefighter studies that have compared nighermen exposed to 9/11 and not expos exposed -- those that were not. we're just scratching the surface for cancers to develop. cause and effect down the line. it will take time. they'll have to be sick people toe be sick people to screen these cancers and identify them early. higher incident cancers. dr. flores, thank you for joining us. and people who lived and worked nearby and never consented to place themselves in harm's way. we talk to a first responder who may be paying the price long term for the work he did in those days. >>> welcome back. the danger in the dust is our focus on this 9/11 anniversary. we found in the years after the september 11th attacks just how dangerous the by-products of the attack could be, the fires, smoke, debris, and the risks involved in long term exposure. david howly is a retired new york city police officer who responded to the attacks and the building collapse and he's been plagued by several different cancers in the years since. how long afterward did y