The majority of CCPs are landfilled, placed in mine shafts or stored in ash ponds at coal-fired power plants. Groundwater pollution from unlined ash ponds has been a continuing environmental problem in the United States. Additionally some of these ponds have had structural failures, causing massive ash spills into rivers, such as the 2014 Dan River coal ash spill.
A considerable amount of CCPs are buried, placed in mine shafts or stored in ash ponds at power plants. Pollution from unlined ash ponds has been a recurring environmental issue in the U.S., with some ponds experiencing structural failures and causing large-scale spills into rivers, such as the 2014 Dan River coal ash spill.