Scientists investigating mass pollution which injured and killed hundreds of sea birds along the south coast say the source of the contamination may never be known.
Around 300 birds, mostly guillemots, were treated at the RSPCA West Hatch centre near Taunton following the spill. The Maritime and Coastguard Agency said that it had been unable to trace the source of the spill and confirmed it has closed the investigation.
After tests were carried out on a sample of the product, it was identified as polyisobutene, or polyisobutyliene. This is a fairly common chemical carried aboard ships and it is produced in a large number of countries.Despite further tests, we have been unable to identify specific components of the product that may have helped us find the source. Unless we receive any new information, our investigation is now closed.