Organised crime gangs may "launder" low-price dyed fuel, removing the dye and selling it illegally to unsuspecting motorists at the higher price of undyed fuel. Paramilitary groups connected to political unrest in Northern Ireland have established laundering plants on both sides of the Irish border. In 2004, Northern Irish police discovered an illegal facility capable of removing the dye from . In 2009, customs officials shut down a plant capable of removing the dye from 6.5 million litres of fuel per year. In 2011, a plant capable of processing 30 million litres was discovered.