Almost every coal-fired power plant in the US is contaminating groundwater with unsafe levels of toxic pollution, according to the first comprehensive analysis of the consequences of coal ash waste disposal. Of the 265 US power plants that monitor groundwater, 242 have reported unsafe levels of at least one pollutant derived from coal ash, which is the remnants of coal after it is burned for energy. More than half such facilities report unsafe levels of arsenic, a carcinogen linked to multiple types of cancer, with 60% finding elevated lithium, which is associated with neurological damage.