Three firms are facing joint prosecution after a landslide at Derrybrien in Co Galway last year.
An ESB subsidiary, ESBI engineering, Gort Windfarms from Co Kerry, and Ascon Limited of Kill, Co Kildare, are all facing legal action from Galway County Council and the Shannon Regional Fisheries Board on charges of causing pollution.
A consultant's report earlier this year found construction work on a wind farm was the main cause of the landslide at Derrybrien.
Work on the project has since been suspended.
The three companies are expected to contest the court case, which is likely to take place later this month.