Customs officers and gardaí have this afternoon raided an illegal oil-laundering plant in Inniskeen, Co Monaghan.
Officers believe the plant was being used to wash the dye from marked diesel, otherwise used for farm machinery, to sell it on as regular diesel at a higher price.
No arrests were made at the scene and it is not yet clear whether the washed diesel was sold on privately or through petrol stations.
Seven tanks and two trailers with the capacity for producing 60,000 litres of unmarked diesel per week were seized at the location near Carrickmacross.
It is believed that the loss to revenue from such an operation is about €1 million per year.
