International conventions
Because oil spills ignore international borders, the member States of the International Maritime Organization complemented the International Convention for the Prevention of Pollution from Ships (Marpol Convention) with the International Convention on Oil Pollution Preparedness, Response and Cooperation (OPRC), which entered into force on 13 May 1995.
The signatory countries agreed to set up national and regional response preparedness systems and to respond to accidental oil pollution. They developed international relations in this field and required all vessels flying their flag, offshore rigs in their jurisdiction and maritime ports on their territory to have contingency plans to combat any pollution incident for which they are responsible.