The Facility Response Plan regulations require subject facilities to prepare and maintain a site plan diagram that includes, among other things, the contents of bulk oil storage tanks, drum oil storage areas, and surface impoundments (40 CFR Part 112 Appendix F).  When the contents of these storage units frequently vary, can the facility use a log or supplemental sheet to indicate their contents rather than indicating this information directly on the diagram?

Yes. Similar to the SPCC plan, the facility owner or operator may note the general contents of each container directly on the diagram and then provide more detailed content information separately in a supplement sheet, log, or electronic system.  If information is provided separately, the diagram should note that contents vary.