I have had seen dozens of facilities covering (albeit very poorly) a process that is NOT a PSM/RMP covered process because some consultant told them it was. The consultant(s) would point to an old statement by EPA that the Threshold Quantity (TQ) determination was based on the process’s ability to hold an amount exceeding the EHS TQ(s). This was grossly incorrect and just this year EPA has finally corrected the record.
NOTE: an example of this would be a small process that has two (2)- 1,500 gallons NH3 storage tanks; one (1) tank is kept empty just in case there is an issue with the in-service tank or its relief valves. In the beginning, both tanks were utilized, but due to a change in business, their need for that much NH3 was no longer. I attempted to help them put controls in so they could withdraw their RMP and manage the process as a non-PSM/RMP covered process. An environmental consultant told the facility I was wrong and that the process was covered based on the potential volume. Heck, she did not even let them claim 85% of these vessels – she required them to assume each vessel was 100% full!!!