A major environmental clean-up is under way in south Armagh where the contents of an illegal landfill site are being sent back across the border.
Tonnes of illegal waste was dumped
A fleet of lorries has carried hundreds of tonnes of household waste including old nappies and decaying food back to the Republic.
The tonnes of illegal waste netted the rubbish racketeers thousands of pounds.
BBC NI environment correspondent Martin Cassidy said it is the first time illegal waste has been repatriated.
"It may just be household waste but it's dangerous stuff - as it decays toxic chemicals are released into streams and the water table below, which once polluted can never be cleaned up," he said.
"In the first operation of its kind, they are digging the waste up and sending it back where it came from - south of the border."
Environmental officials from the Republic, who themselves are cracking down on the illegal waste, helped oversee the repatriation operation.
The aim is to make life more difficult for the racketeers who make their money by avoiding landfill taxes.
Toxic chemicals are released into streams
The authorities say that each lorry load of illegal waste can be worth up to £2,000 to the operators of illegal land fill sites.
A number of other illegal dumps along the border are now under investigation and the authorities say they plan to make the perpetrator pay the costs involved in repatriating the waste and having it properly disposed of in engineered sites.