Some 50,000 litres of light fuel oil leaked into the Kokemäki river from a Pori Energia heating plant in western Finland on Thursday.
Dozens of emergency service personnel and a private oil clean-up team are hard at work in the city of Harjavalta to remove the spilled oil.
Due to overnight frost, ice has formed in the river – which is both a blessing and a curse for the crew's efforts, as ice slows the spread of the oil but also hinders the workers trying to clean the water.
Emergency services say they have no precise data on the exact extent of the spill, which nonetheless represents an area several kilometres in diameter.
"All the senses are needed to detect this fuel oil," says fire chief Timo Lehtonen from the Satakunta Emergency Department. "We might see it and smell it, but we also often need to touch it or even taste it to be sure it's what we're looking for."
Human error, chances good
The accident occurred due to a discharge pipe being incorrectly attached to a truck carrying fuel oil. The oil seeped out of the tank and into the river through a drainage sewer.
Emergency services cordoned off the spread of the substance with barrier booms, which will be moved later on Friday.
"They're now set up crosswise in the middle of the river," Lehtonen says, "But we're going to move them in order to direct the oil onto the shore to be collected via vacuum truck."
The Lamor environmental solutions company is using specialised boats to control part of the spill even while the booms are being realigned to help the efforts along. A pick-up trawler will collect the oil after it is gathered in one place by the boats.
CEO Juha Muhonen says the chances of the river being cleansed are good.