Regulation 26 of Annex I of MARPOL 73/78 (Prevention of Pollution by Oil) requires every oil tanker of 150 GT and above and every ship, other than an oil tanker, of 400 GT and above to have on board an approved Shipboard Oil Pollution Emergency Plan (SOPEP). Such a plan is required to be drawn up in accordance with the "Guidelines for the Development of Shipboard Oil Pollution Emergency Plans" adopted by Resolution MEPC.54(32) (amended by Resolution MEPC.86(44)). This requirement has been in force since 4 Apr 1993.