In Machine Guarding: The Second Alternative, equipment expert witness Albert Rauck, P.E., CSP, writes on machinery safety devices:
The first thought should be given to the design of the process. Remember the danger results from the combination of hazard and exposure. Eliminate either one and the dangerous condition no longer exists. Is it possible to eliminate the human from the process through automation? Can the operator be relocated to a safer position? Can the process be changed to eliminate the hazard? Obviously the ideal time to make these decisions is during the design of the process but other opportune times are during a renovation, machine rebuild etc. Often it is not possible to completely design out the dangerous condition but it is possible to greatly reduce the risk to a more acceptable level. The reason that this is the highest priority is that it eliminates the dangerous condition whereas the other alternatives do not.