Mandatory pre-wash MARPOL Annex II

Chemical tankers which have discharged cargoes that present a major hazard to the marine environment in the Netherlands (category X substances) are required to carry out a mandatory prewash before leaving the port. An inspector from the Human Environment and Transport Inspectorate (ILT) must be present during the prewash. This is required by law in the Netherlands. The ILT intervenes if the pre-wash is not carried out or not according to the requirements.

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Requesting an ILT mandatory pre-wash

A pre-wash is mandatory for ships that unload a MARPOL Annex II category X product in the Netherlands. A pre-wash is also mandatory if too much cargo residue remains in the tanks after discharging a category Y or Z product.

A pre-wash after discharging a category X substance and a paraffin wax must be reported to the ILT (Port State Control) 24 hours in advance. This may be done through the ship's agent. An exception applies to the Rotterdam port area. If you unload here, you must report directly to the Rotterdam Port Authority.

You or the ship's agent must notify the ILT by telephone 3 hours in advance by dialling +31 (0)88 489 0000.

Requirements for the mandatory pre-wash

There are a number of requirements to be met by the parties involved. This is to ensure that the process runs as smoothly as possible.

  • Before pre-wash, the ship’s tanks must be emptied and stripped. This must be done according to the chemical tanker’s approved Procedures and Arrangement Manual.
  • The vessel or tanker in which the pre-wash water goes must be present at the pre-wash.
  • The ILT inspector indicates when the pre-wash may start. Everything must be ready before the ILT inspector comes on board. If this is not the case then the ILT inspector may disembark.
  • If the ILT inspector requires a boat to get to the ship, this will be arranged by the ship’s agent and provided at the ship's expense. The ship's agent must also ensure that the ILT inspector can get on board via the gangway. For safety purposes, if the ILT inspector must board and/or disembark before sunrise or after sunset, a crew of 2 must accompany the small boat.

The following also applies:

  • The pre-wash is to be carried out according to the instructions in Chapter VI, Annex II of the International Convention for the Prevention of Marine Pollution from Ships (MARPOL) Annex II.
  • The residual product and water mixture created during the pre-wash must be disposed of at a reception facility at the port of discharge. This must involve emptying the entire tank.
  • Water that is stored in the tank after pre-washing may be discharged into the sea. This is stated in the discharge standards in regulation 13.2, MARPOL Annex II.

Additional requirements after discharging paraffin wax

If a ship has carried paraffin wax (MARPOL Annex II category Y), too much product may remain in the tank. The Netherlands therefore has additional requirements for washing tanks that contained wax products. A pre-wash is always mandatory for ships after discharging paraffin wax. 

Before a pre-wash can be carried out, a ship must meet the following additional requirements:

  • The chemical tanker must follow an additional procedure beforehand. The ship's agent is given information about this when registering the pre-wash. The ship's agent communicates this information to the ship before unloading.
  • For a cargo of category Y paraffin wax, the pre-wash may start before the ILT inspector is on board. However, this must be agreed in advance.