The plant managers had been warned of erratic readings of the core pressure prior to the emergency, but disregarded them, knowing that they would be changing the fuel rods the next day.

In contrast, Bolen considers sabotage a better explanation for both the initial emergency and the failure of the backup systems.

Bolen's suspicions are raised when he learns that the wife of Howard Ives, one of the men trapped in the containment, has just been found dead, an apparent suicide.

When a sound resembling human breathing is overheard on speakers linked to the containment area, Bolen suspects that someone is still alive inside the reactor.

Stone, remembering that the fuel rods were due to be changed, realizes that the crane, under computer control, is following its orders to open the reactor.

The Thermal Vacuum Test known as Chamber A in Building 32 at NASA's Johnson Space Center was used as the interior of the film's Nuclear Station 34.