I recently participated in a PHA for a large flammable liquids process and during the “facility siting” portion of the PHA we took a detailed tour of the process. During which, several significant “impact” hazards were identified. Of course, the long-time engineering manager (40 plus years of fine service at the facility) quickly went to the “it has been that way for 50+ years and no one has hit the pipe/pipe support or dropped a load on the pipe/pipe support“. So the question is… How much “safety credit” should we give based on a 50 year run of no damage/incidents when we can plainly see that the scenario has a high potential?