Northern Ireland's largest diesel laundering plant, capable of evading up to £5.5m of revenue a year, has been dismantled in Co Armagh.
The plant, which had the capacity to launder eight and a half million litres of fuel a year, was uncovered when Revenue and Customs investigators raided farm buildings in the Derrynoose area.
Around 20,000 litres of laundered green diesel were seized with three tonnes of cat litter - a product used to remove the dyes and markers from diesel tanks and pumping equipment.
Customs assistant director Mike Connelly said:
"This plant was substantially larger than any previous laundering operation we have detected in Northern Ireland.
"People need to be aware of the environmental and safety issues surrounding the laundering of fuel, which is often done in rural locations."
Indiscriminate dumping of the by-products from the laundering process can cause severe damage to arable land and water systems, and taxpayers and local ratepayers have to pay for the clean-up and disposal costs, he added.
Customs officers removed several items for forensic testing and investigations continued.
© Press Association