Augean

Au·ge·an

Of or pertaining to Augeus, king of Elis, whose stable contained 3000 oxen, and had not been cleaned for 30 years. Hercules cleansed it in a single day. (Class. Myth.)
Hence: Exceedingly filthy or corrupt.

Augean stable: an accumulation of corruption or filth almost beyond the power of man to remedy.