33,000 litres of mineral oil have been seized in Monaghan as part of a cross-border operation targeting fuel laundering.
Three people were also arrested at a premises in Crossmaglen as part of the same investigation over the weekend.
On Friday and Saturday, Revenue officers carried out a search of a house and outbuildings in Agnaglogh, Castleshane.
The intelligence-led operation targeting mineral oil laundering also involved Gardai and Monaghan County Council’s Fire Service.
A distillation plant to launder marked mineral oil was discovered at the property, with 33,000 litres of mineral oil, 10,000 litres of by-product sludge, a lorry and an 18,000 litre oil tank as well as a generator, pumps hoses and a filtering system was seized.
A man was interviewed, with investigations on-going with a view to prosecute.
Simultaneously, a search was carried out by Her Majesty’s Revenue and Customs at a premises on Annaghgad Road, Crossmaglen.
Three people were arrested there with €35,000 and £6,000 in cash as well as a car seized.
A spokesperson for Revenue said the collaboration of all agencies north and south was significant in bringing a successful outcome to this operation and other operations targeting fuel smuggling and shadow economy activity