A man has been arrested following the discovery of a large fuel laundering Plant near Carrickmacross, Co Monaghan.
Customs 0fficers said the plant had the capacity to launder an estimated three million litres of fuel a year, costing the Exchequer about €1.8 million.
Customs impounded 12,000 litres of laundered fuel and a truck. Ancillary equipment was also dismantled and seized.
Investigations are continuing with a view to prosecution, Customs said.