Emergency Stop Button

An emergency stop button, often called an e-stop, is a mushroom-shaped push button, typically colored red on a yellow background, mounted on a machine or along a production line so that any worker who sees a dangerous situation developing can stop the equipment immediately without hunting for the normal control panel. Pressing the button cuts power to the machine's hazardous motion directly, rather than merely sending a stop command through the ordinary control logic that might itself be malfunctioning, and the button latches down once pressed so the machine cannot restart until an operator deliberately twists or pulls it back out and then issues a fresh start command. Long production lines and large machines carry several emergency stop buttons spaced along their length or around their perimeter, on the reasoning that the button has to be within a worker's immediate reach at the moment something goes wrong, not merely present somewhere on the equipment. The device is now a near-universal, standards-mandated fixture of industrial machinery design, precisely because it is meant to be the single most reliable way to stop a machine that safety codes can specify.