Investigators were unable to recover sufficient body tissue to determine whether the crew had been physically incapacitated at the time of the crash. Toxicology reports conclusively ruled out toxic gases, alcohol, and drugs as possible cause for the crash. Milton Helpern, Chief Medical Examiner, decided that having relatives attempt visual identification of the crash victims was inhumane and ordered dental and fingerprint comparisons. In early July, the CAB announced their investigators believed that a cotter pin and a bolt missing from the rudder mechanism might have caused Flight 1's crash. Though considered to be a "mechanic's oversight", the CAB nevertheless wired all 707 operators to inform them of the potential danger of the assembly.