What do you expect next?
Very poorly mismanaged incident, pointing fingers....and who suffers? Indigenous people with delivery of oil slick water tanks. Sigh.
True, numerous abandoned mines are toxic hazards everywhere...seepage from those holes/shafts eventually do enter the water table. I think the EPA frame of mind was earnest,(I still don't trust them from personal experience) but faltered not having a stop gap measure in case something went wrong.
Prepare for the worst, hope for the best.