Customs officers have uncovered a major oil-laundering plant -- the biggest so far this year and the third largest ever found in the Republic of Ireland.
Backed up by heavily armed gardai from the regional support unit, customs swooped on the diesel laundry in a commercial yard in Co Monaghan yesterday morning.
The plant, at Longfield, Castleblayney, Co Monaghan, had the capacity to launder about 15 million litres of diesel a year.
It was the sixth laundry find this year and its capacity represents more than half of the combined total of the other five.
Last night a senior officer described it as a highly significant find and a major blow to the cross-border gang behind the fuel fraud.
Last year -- when nine plants capable of processing 80 million litres of fuel annually were seized -- was the most successful for customs against the gangs so far, according to the Customs manager in the Border region, Sean Kelleher.
"It could take you up to 10 years to seize nine plants and we achieved it in one year," he added.
The latest laundry was located in a curtain-sided lorry in the yard. Officers seized the lorry, two 40-foot containers, two tankers, a van and 40,000 litres of laundering product.
A substantial quantity of toxic waste was also uncovered at the site.
Gardai detained three men for questioning, one in his early- 60s and two in their mid-30s.
They were being questioned last night at Carrickmacross and Castleblayney stations while inquiries into the seizure were being stepped up.
Revenue Commissioner Liam Irwin said fuel laundering and trading in illicit fuel represented a significant threat to the Exchequer and hurt legitimate businesses.
"We are determined to take every action necessary to stamp out this form of criminality," he added.
The Revenue are now working with their counterparts in the UK to find a new fuel marker to combat the evasion of duties.
The laundering is carried out to remove the chemical markers from low-duty diesel and then it is sold on as road fuel.
Revenue officials have again advised motorists to purchase diesel from known branded outlets only to prevent damage to their engines and to report any suspicions about a particular outlet to the Revenue or the Irish Petrol Retailers Association.
Last month the Irish Independent revealed that the millionaire bosses of the laundering gangs were now extending their networks overseas to maximise their profits.