Thousands of tonnes of buried illegal waste from the Republic of Ireland are being left to rot in fields across the Dungannon District.
Lack of landfill capacity in the South is holding up the repatriation of waste from three illegal dumps in the Dungannon area and one in Cookstown.
The cost of digging it up and moving it back across the Irish border is furthering delays.
Whereas the majority of illegal dumping sites across Northern Ireland have been cleared, those in East and South Tyrone have been left to fester and potentially pollute the local environment.
The Northern Ireland Environment Agency (NIEA) believes more than 30,000 tonnes of waste have been dumped across three sites at Galbally, Ballygawley and Sandholes.
Derek Williamson from agency’s environmental crime unit said the waste originated in the Republic.
He said there are fears east and south Tyrone is being used by “unscrupulous criminals to illegally dispose of waste”.
“We have not assessed any immediate public health implications. However, we would advise anyone who finds waste illegally dumped not to touch it, but to report it appropriately.”
Agriculture Minister Michelle McIlveen said it was unacceptable that the situation was continuing, even though waste repatriation began in 2010.
“The issues that I understand are in relation to cost, but also with regard to a lack of capacity for land waste in the Irish Republic”, she said.
To date twelve sites have been cleared with 93,000 tonnes of waste sent back under a cross-border agreement.