High-viscosity PIB carried by ship to be subject
to stringent discharge requirements


October 22, 2013

IMO’s Working Group on the Evaluation of Safety and Pollution Hazards of Chemicals (ESPH 19), meeting at IMO Headquarters from 21 to 25 October, has agreed to classify high-viscosity PIB (Polyisobutylene) as category X for carriage by ship, thereby prohibiting the discharge of cargo residues into the sea.

The categorization and carriage requirements for high-viscosity PIB will be included in the annual MEPC.2/Circular on the Provisional categorization of liquid substances, usually issued by IMO on 17 December each year and will be put forward for inclusion in the next edition of the International Code for the Construction and Equipment of Ships carrying Dangerous Chemicals in Bulk (IBC Code) which lists chemicals and their hazards and gives both the ship type required to carry that product as well as the environmental hazard rating. Amendments to the IBC Code are put forward on an annual basis so the next amendments would be considered during 2014, for inclusion in the IBC Code with an effective implementation date of 1 July 2016.

Category X under the International Convention for Prevention of Pollution from Ships Annex II Regulations for the control of pollution by noxious liquid substances in bulk includes noxious liquid substances which, if discharged into the sea from tank cleaning or deballasting operations, are deemed to present a major hazard to either marine resources or human health and, therefore, justify the prohibition of the discharge into the marine environment.

For substances under category X, a tank from which a substance in Category X has been unloaded, must be prewashed before the ship leaves the port of unloading. The resulting residues must be discharged to a reception facility until the concentration of the substance in the effluent is at or below 0.1% by weight.

MARPOL Annex II lists four categories for noxious liquid substances carried in bulk:

• Category X: present a major hazard to either marine resources or human health and, therefore, justify the prohibition of the discharge into the marine environment;

• Category Y: present a hazard to either marine resources or human health or cause harm to amenities or other legitimate uses of the sea and therefore justify a limitation on the quality and quantity of the discharge into the marine environment;

• Category Z: present a minor hazard to either marine resources or human health and therefore justify less stringent restrictions on the quality and quantity of the discharge into the marine environment; and

• Other Substances: considered to present no harm to marine resources, human health, amenities or other legitimate uses of the sea when discharged into the sea from tank cleaning of deballasting operations.

Previously, PIB was classified as category Y material but there was no differentiation between high or low viscosity grades. Low-viscosity PIB will remain as a category Y product.

IMO – the International Maritime Organization – is the United Nations specialized agency with responsibility for the safety and security of shipping and the prevention of marine pollution by ships.

Source: IMO