Artikel 6

1. For the sole purpose of this Agreement the North Sea area is divided into the zones described in the Annex to this Agreement.
2. The Contracting Party within whose zone a situation of the kind described in Article 1 of this Agreement occurs, shall make the necessary assessments of the nature and extent of any casualty or, as the case may be, of the type and approximate quantity of oil or other harmful substances and the direction and speed of movement thereof.
3. The Contracting Party concerned shall immediately inform all the other Contracting Parties through their competent authorities of its assessments and of any action which it has taken to deal with the oil or other harmful substances and shall keep these substances under observation as long as they are present in its zone.
4. The obligations of the Contracting Parties under the provisions of this Article with respect to the zones of joint responsibility shall be the subject of special technical arrangements to be concluded between the Parties concerned. These arrangements shall be communicated to the other Contracting Parties.