Transcription: In 1979, the worst nuclear accident in U.S. history occurred at the... Well, we've already had all of the ingredients of a disaster. We've had drug use implants. We've had control room operators asleep at the switch. We've had people tying open vital valves with rope. If you look at the federal government studies from the Nuclear Regulatory Commission, there's basically an unlimited possibility for ways in which a major accident can occur.