The investigators who descended upon TMI in the wake of the accident reported that there were fourteen different meanings for red, and eleven for green. The consistency we now expect in countless rounded buttons and red warning lights was totally absent at Three Mile Island. Sometimes the lights were above the control they corresponded to, sometimes off to the side. They weren’t even grouped in a way that made sense: On the very same panel that would warn of water leaking from the reactor were alarm lights indicating elevator trouble.
