Fuel launderers in a border area of Northern Ireland dumped toxic waste in the same place 10 times, it has been revealed.
Former republican paramilitaries operating with impunity in the South Armagh region were blamed but there have been virtually no prosecutions, the Stormont Assembly heard.
The sludge was produced in the treatment of duty free diesel intended for agricultural use to remove markers which could snare illegal motorists.
Regional Development Minister Danny Kennedy claimed: "They are dumping the diesel where once they were dumping the bodies."
Mr Kennedy, who represents parts of South Armagh for the Ulster Unionist Party, said "It is inescapable to me that monies generated as a result of this black economy ultimately will find their way back to republican paramilitaries," he alleged.
In January it was revealed nobody has gone to jail for fuel smuggling in Northern Ireland in the last decade. But two heavy goods hauliers face losing their licence for using non-duty paid diesel and 17 more are under investigation, Stormont Environment Minister Alex Attwood said.
Mr Attwood said a byproduct sludge produced during the laundering process had been dumped in the same part of South Armagh 10 times. The minister said Holyhead in Wales was being used as a gateway to Great Britain by haulage firms using black market fuel because controls were not as tough as those in Scotland.
"The situation is acute and there is going to be a need to escalate all the enforcement action," Mr Attwood added.