On June 28, 2010, in response to the Gulf oil spill, PHMSA issued an Advisory Bulletin to all liquid pipeline operators, requiring operators to review and, if necessary, revise and update their spill response plans. Such plans are required under 49 C.F.R. Part 194 (DOT’s implementation of OPA-90 spill response requirements). PHMSA notes that in addition to submitting updated plans to the Agency, copies of plans must be maintained at field facilities, and it is expected that PHMSA will ask for them during audits. See 75 Fed. Reg. 36773