Finnish fuel firm Neste announced on Wednesday that lab tests confirmed the white substance that washed up along the shore in Hanko last week very likely came from the wash water of a vessel used in the company's marine transport operations.
It said the substance consisted of used frying oil, animal fat and vegetable oils. An investigation of the material by authorities continued on Wednesday.
A joint press conference about the matter is planned on Wednesday afternoon, with representatives from the town, Western Uusimaa rescue services, environmental group WWF Finland and Neste taking part.
The white clumps began appearing along Hanko's extensive shoreline a little more than a week ago.
People started noticing the material piling up on Sunday 27 January, soon after which local rescue services and the Finnish Environment Institute (Syke) started investigating the matter.
Then, last Tuesday, piles of dead fish began appearing on the southern coastal town's shores. There were initial concerns that the two events were related, but the local fire chief said a veterinarian's inspection of fish samples suggested they were most likely killed in a fishing trawler's net.
At the moment, the white substance and the fish deaths do not appear to be related.
WWF Finland organised a volunteer cleanup effort, which brought around 140 people to Hanko's shores over the weekend. The cleaning effort continued this week.
Neste has vowed to pay for any damage caused by the company's operations.
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