Investigators probing the pollution which has hit thousands of seabirds off the Westcountry coast have identified seven ships which may have been responsible, it emerged yesterday.
More than 3,000 birds have washed up along the Dorset, Devon and Cornwall coast coated in the glue-like lubricant, polyisobutene (PIB).
The substance, typically added to engine oils, first affected hundreds of birds in February. A second wave of casualties came ashore last month.
Officials at the Maritime and Coastguard Agency (MCA) are hunting the source of the chemical, which can currently be released legally under certain conditions.
Katie Ware, UK representative to the International Maritime Organisation, said: "The MCA counter-pollution team has identified an area and a time-slot when we think that this discharge was made. We have identified a possible 62 ships that transited the area at that time and we've managed to narrow the number down to a possible seven ships which could have caused the discharge."
Dead and ailing birds started appearing earlier this year prompting demands for a ban on discharges of PIB. Wildlife agencies say the death toll from both spills has reached 2,400, with 500 more receiving urgent medical care.
The MCA says it will prosecute the boat responsible if the release turns out to have been unlawful.