A clear-up operation to remove polluted parts of two beaches in Fife has been completed and they are set to re-open.
The beaches in the villages of Limekilns and Charlestown have been closed since last month following an oil spill.
Around 600 tonnes of contaminated seaweed and sand has since been removed at a cost of £600,000 to Fife Council.
But an investigation has been unable to find the source of the leak.
Scottish Environmental Protection Agency (SEPA) chief officer Ian Buchanan said: "An extensive investigation carried out by regulatory, chemistry and marine science staff at SEPA has ruled out all identified land-based sources for the pollution found on Limekilns and Charleston beaches.
"SEPA analysed samples of the contamination and compared the results to samples taken from potential sources.
"No matches were found, and as result SEPA's investigation is closed, unless further information comes to our attention in the future."
Mr Buchanan said early suggestions that the oil had come from a land drain could not be substantiated.
Investigations by the Marine Coastguard Agency and Forth Ports, which owns the nearby port of Rosyth, could also not identify the source of the leak.
The beaches will reopen to the public on 23 March.
Derek Crowe, of Fife Council's roads and transportation service, said: "This has been a massive partnership operation with many organisations working together to get this area cleared up and back in public use.
"It's great news that we can re-open the beaches as I know people have been missing the opportunity to use this much loved resource. I'd like to thank everyone for their patience while the work was under way.
"Although residents may still occasionally see a sheen on the water, this will disperse naturally."