the coal ash will never be fully removed from the river. this is due to samples passing human health screening, the potential for historical contamination to become re-suspended, and removal being more detrimental to certain endangered species than the coal ash itself. in addition, the coal ash is already mixed in with existing sediment, complicating its removal further. epa estimated that about 72 percent of all the toxic water in the country comes directly from coal-fired power plants.