Agreement concerning Cooperation in taking Measures against Pollution of the Sea by Oil (Sept. 16, 1971) Countries/Territories Entry into force Simple signature Denmark Oct 16, 1971 Sep 16, 1971 Finland Oct 16, 1971 Sep 16, 1971 Norway Oct 16, 1971 Sep 16, 1971 Sweden Oct 16, 1971 Sep 16, 1971