With little scientific analysis to show it was safe, the U.S. Environmental Protection Agency (EPA) recommended the use of coal ash and other waste to build roads and structures over the past 10 years.

According to a new report from EPA’s inspector general, the agency promoted the use of leftovers from coal-fired power plants, such as fly ash bottom ash and boiler slag , in materials for wallboard, road surfaces, golf course fill, concrete and other applications. EPA went this route in order to reduce waste, even though the coal waste contained low concentrations of arsenic, lead and mercury, all of which can seep into groundwater supplies and pose a potential danger to human health.

According to the Inspector General report, “EPA did not follow accepted and standard practices in determining the safety of the 15 categories of CCR [coal combustion residuals] beneficial uses it promoted through the C2P2 program. EPA’s application of risk assessment, risk screening, and leachate testing and modeling was significantly limited in scope and applicability. Without proper protections, CCR contaminants can leach into ground water and migrate to drinking water sources, posing significant public health concerns.”

The use of coal residues as filler nearly tripled between 2001 and 2008, from 4 million tons to 12 million tons a year, according to the report.

-Noel Brinkerhoff