Go to content

Prewash of seagoing tankers

Seagoing tankers that discharge substances with a high risk of environmental pollution may only depart for sea after a prewash. In the Netherlands, a Human Environment and Transport Inspectorate (ILT) inspector must be present during the prewash. The ILT will intervene if the prewash is not carried out, or not carried out in accordance with the applicable requirements.

Bekijk deze pagina in het Nederlands

Mandatory prewash

A prewash is mandatory for seagoing tankers discharging in the Netherlands any liquid substance falling under MARPOL Annex II in the following categories:

  • Category X.
  • Category Y (paraffin wax).
  • Category Y (other than paraffin wax), if excessive cargo residue remains in the tanks.
  • Category Z, if excessive cargo residue remains in the tanks.

Mandatory prior notification

The ship master must notify the prewash in advance, as follows:

  • For a Category X liquid substance or a paraffin wax under Category Y: at least 24 hours in advance.
  • For other substances subject to the prewash requirement: at least 3 hours in advance.
  • If discharging in the port area of Rotterdam: notify the Port of Rotterdam Authority.
  • If discharging in another port: notify ILT (Port State Control) on +31 88 489 00 00.

Prewash preparations

Before the ILT inspector comes on board, the ship master must ensure that the vessel is fully prepared for the prewash. This includes:

  • The tanks must be emptied and stripped in accordance with the vessel’s Procedures and Arrangements Manual (P&A Manual) approved by the flag state.
  • The vessel or tank truck receiving the wash water must be in place and ready.
  • If the ILT inspector can only access the vessel by launch, the ship's agent must arrange for this launch and ensure safe boarding via the gangway. If the inspection takes place after dark, the launch must have a 2-person crew for safety reasons. The cost of the launch and crew is for the account of the seagoing vessel.
  • For paraffin wax under Category Y, additional preparations are required. The ILT will provide specific instructions upon notification of the prewash. In such cases, the ILT may agree that the prewash may begin before the ILT inspector is on board.

If the preparations are not complete, the ILT inspector may leave the vessel upon arrival.

Execution of the prewash

The ILT inspector will determine when the prewash may begin. During execution, the following applies:

  • The prewash must be carried out in accordance with the procedures described in the P&A Manual of the seagoing tanker.
  • The washing fluid containing the product residue must be delivered to a reception facility in the discharge port.