WAC 296-806-42546. Follow these requirements for flour-handling machines

You must make sure the following safeguards are used when flour-handling systems are run in electrical unity with one another: (1) When the beginning of the system is located far from its final delivery end, make sure: (a) All electric motors operating the system have one control at each end; and (b) Either control will stop all motors. (2) Arrange control circuits for magnetic controllers so opening any limit switch on an individual unit will deenergize all motors on that unit.