Around 10,000 litres of highly toxic diesel sludge has been found dumped in several locations around north Co Louth.
Ten containers were located on roadsides at four different locations in the county, apparently having been pushed off a truck.
One of the biggest finds was near the racetrack on the edge of the town where four containers were discovered.
All of them had been damaged. At least one had leaked the black tar-like sludge left by diesel launderers when they ''wash'' the green dye from cheaper marked diesel.
The leaked sludge could pose a major pollution threat.
Louth County Council has begun work to remove the containers and the leaked material at an expected cost of around €10,000.
Over the last number of years cleaning up diesel sludge has cost the taxpayer several million euro.
''Washed'' diesel, which damages regular diesel engines, is sold on as road fuel at huge profit.
