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 significant portion of CCPs are disposed by landfilling, storing them in mine shafts or ash ponds at power plants. Pollution from unlined ash ponds has been a recurring environmental concern in the U.S., with some ponds experiencing structural failures and causing massive spills into rivers like the 2014 Dan River coal ash spill.