Quarries supplying gravel, sand and stones for the new N6 Dublin to Galway dual-carriageway have been closed down after it was discovered they were illegal.
At least two of the quarries shut down last week were involved in providing material for the massive road building, and there may be more closures in the coming days.
Westmeath County Council has confirmed that the two sites did not have proper planning permission, and it advised contractors Ascon accordingly. The council also reminded Ascon of its contractual obligation to rely on material from authorised sites only.
The embarrassing development came after the National Parks and Wildlife Service visited the quarries and ordered the closures.
The quarries were operating on private land and one of them is located in an area of special conservation - an Ice Age esker ridge.
"We understand that the contractor has ceased acquiring material from these sites," Westmeath County Council said.
Furthermore, the council is to examine the possibility that one of the quarries could be a threat to a local water source. Ascon has declined to comment.
It is thought the quarries were discovered after locals complained recently about the sharp rise in the number of large vehicles travelling on otherwise quiet roads.
This section of the dual-carriageway will take motorists from Athlone to Kinnegad before connecting with the M4 at Kinnegad.
The Kilcock to Kinnegad M4 motorway will be opened on December 12th.