The original mining company should be sued if any of it still exists, the EPA was trying to clean the mess they left, mess which would have already spilled long ago without the EPA by the way.
I don't know whether that will be right. The mining company was already paying for the cleanup, which was being undertaken by the EPA. And also, the breach happened, after the EPA guys mistakenly drilled a concrete wall, which was holding back large amount of toxic waste. In my opinion, the EPA is solely to blame for this catastrophe.