A major disposal operator has been shut down after the discovery of hundreds of thousands of tons of waste buried illegally on land near Londonderry.
Northern Ireland environment minister Alex Attwood signed off an order following an investigation by his department's environmental crime unit which unearthed a sophisticated racket to conceal vast amounts of waste in the Mobouy area.
He said: "Material was mangled and shredded to hide its original sourcing, with illegal landfills being topfilled with soil and clay to deceive and hide illegal waste.
"The scale of this is clearly well organised - the scale of this means it involves organised crime."
The owner of the waste management facility closed down - which has not been identified - has now been given two months to transfer the material to a legal landfill site for disposal.
Owners of the land where waste was hidden have also been ordered to take action to prevent environmental damage by getting rid of polluting liquid.
The minister revealed he is setting up a special waste crime task force as part of new measures to crack down on criminals involved.
Chris Mills, a former chief executive of the Welsh Environment Agency, is undertaking an immediate review of the workings of the Department of the Environment's waste unit. Up to 25 sites where risk may exist are to be checked out and district councils have been told to tighten up on waste collection arrangements in a bid to thwart illegal dumping linked to fuel laundering.
Two people have been questioned as part of Operation Sycamore, and according to the department more arrests are expected. But Upper Bann MP David Simpson said criminals running the multimillion-pound fraud were still avoiding prosecution - even though illegal plants had been dismantled.
He said the Government had talked about a new fuel marker for long enough, but it was now time for action. One plant discovered last month, he claimed, laundered 40,000 litres which would have cost the Exchequer £4.8 million in lost revenue.