In the wake of the deaths of over 4,000 seabirds in two polyisobutylene (PIB) spill incidents in the UK, the International Maritime Organization (IMO) has placed all high viscosity PIBs in MARPOL Annex II Category X, which completely prohibits their discharge into the marine environment. Some lower viscosity (lower molecular weight) PIBs will remain Category Y, where their discharge is limited in both quantity and quality but not prohibited.
The decision, made during the October 2013 meeting of the IMO’s Evaluation of Safety and Pollution Hazards of Chemicals (ESPH) in London, requires that all tanks carrying high viscosity PIBs have a full tank prewash and that all residues be disposed of in port, in addition to prohibiting any discharge at sea. The two PIB incidents in early 2013, considered the largest marine pollution incident since the Torrey Canyon oil spill in 1967 where over 15,000 birds were killed, resulted in the deaths of at least 4,000 birds of 18 different species. The UK’s RSPCA West Hatch Wildlife Centre was able to rehabilitate most of the few hundred birds brought into care alive. A similar spill in 2010 affected hundreds of birds along the Dutch coast and first brought attention to the effects of PIBs discharged into the ocean on wildlife.
Environment, wildlife and conservation groups in the UK began campaigning to have the substances banned but public response, more than 25,000 people signed petitions, is also credited with helping push the decision through. The Maritime and Coastguard Agency made the recommendation to the IMO on behalf of the UK government.
The IMO is an agency of the UN responsible for improving the safety and security of shipping and preventing marine pollution from ships. MARPOL, the International Convention for the Prevention of Pollution From Ships, regulates transport of Hazardous and Noxious Substances (HNS) such as PIBs under Annex II—Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk.