Gardaí, Louth Council officials and customs officers are investigating the latest large scale dumping of highly toxic diesel sludge.
A stolen curtain-sided trailer was found abandoned on the hard shoulder of the M1 motorway just south of the border earlier today.
It contained an estimated 48,000 litres of the toxic by-product left after the colour is "washed" from agricultural diesel.
The waste is in over 45 large containers known as IBCs. There was a leak from at least one of them, which has been treated.
The trailer was abandoned on the northbound carriageway.
Normally this waste is abandoned on remote countryside roads.
It is the first time a large quantity has been dumped on such a busy road.
