it would be weeks before flesher found out the reason for the secrecy. the plane that crashed was an f-117 a the air force's first true stealth aircraft. all of this only came out after a local newspaper reporter began investigating. so this says in the aftermath of the crash the air force issued a warning that the smoke from the burning plane might have been toxic. do you remember that? >> i remember it coming out days later. >> days later. this also says that there was a paper delivered at a nasa conference in 1994, an air force paper, that says some materials may have burned pose serious health risks. radar absorbed material, and a carbon graphite used for reinforcement. knocked said anything about that to you. >> no, no. >> you got a letter? >> i got a letter from a gentleman who was retired but worked on the project the stealth project. >> in this letter he talked about his own experience working on the development of the plane. >> correct. and having to be under full protective hazmat suit, full respirator any time anybody worked around the project