Carriage of chemicals by ship

Regulations governing the carriage of chemicals by ship are contained in the International Convention for the Safety of Life at Sea (SOLAS) and the International Convention for the Prevention of Marine Pollution from Ships, as modified by the Protocol of 1978 relating thereto (MARPOL).

Chemicals carried in bulk

Carriage of chemicals in bulk is covered by regulations in SOLAS Chapter VII - Carriage of dangerous goods and MARPOL Annex II - Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk.

Both Conventions require chemical tankers built after 1 July 1986 to comply with the International Bulk Chemical Code (IBC Code), which sets out the international standards for the safe carriage, in bulk by sea, of dangerous chemicals and noxious liquid substances.  The Code prescribes the design and a construction standard of ships involved in the transport of bulk liquid chemicals and identifies the equipment to be carried to minimize the risks to the ship, its crew and to the environment, with regard to the nature of the products carried.

The IBC Code sets out a list chemicals and their hazards, and identifies both the ship type required to carry that product and the environmental hazard rating.

Chemical tankers constructed before 1 July 1986 should comply with the requirements of the Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (BCH Code) – the predecessor of the IBC Code.

MARPOL Annex II - Carriage of noxious liquid substances in bulk

MARPOL Annex II Regulations for the control of pollution by noxious liquid substances in bulk sets out a pollution categorization system for noxious and liquid substances. The four categories are:

  • Category X: 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; 
  • Category Y: Noxious Liquid Substances which, if discharged into the sea from tank cleaning or deballasting operations, are deemed to 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: Noxious Liquid Substances which, if discharged into the sea from tank cleaning or deballasting operations, are deemed to 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: substances which have been evaluated and found to fall outside Category X, Y or Z because they are 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. The discharge of bilge or ballast water or other residues or mixtures containing these substances are not subject to any requirements of MARPOL Annex II.

The annex also includes a number of other requirements reflecting modern stripping techniques, which specify discharge levels for products which have been incorporated into Annex II. For ships constructed on or after 1 January 2007 the maximum permitted residue in the tank and its associated piping left after discharge is set at a maximum of 75 litres for products in categories X, Y and Z (compared with previous limits which set a maximum of 100 or 300 litres, depending on the product category). 

MARPOL Annex III - Chemicals carried in packaged form

Chemicals which are carried in packaged form, in solid form or in bulk are regulated by Part A of SOLAS Chapter VII - Carriage of dangerous goods, which includes provisions for the classification, packing, marking, labelling and placarding, documentation and stowage of dangerous goods. 

MARPOL Annex III also sets out regulations for the prevention of pollution by harmful substances in packaged form and includes general requirements for the issuing of detailed standards on packing, marking, labelling, documentation, stowage, quantity limitations, exceptions and notifications for preventing pollution by harmful substances. For the purpose of Annex III, “harmful substances” are those identified as “marine pollutants” in the IMDG Code. 

Both SOLAS and MARPOL refer to the International Maritime Dangerous Goods (IMDG) Code, which was developed by IMO as a uniform international code for the transport of dangerous goods by sea.

Preparedness, Response and Liability and Compensation for Chemical Pollution Incidents

Issues related to the preparedness for and response to incidents of chemical pollution is covered by the OPRC-HNS Protocol 2000.  Liability and compensation for incidents involving chemical pollution incidents are covered by the HNS Convention 2010, which has yet to enter into force.