About Coal Ash

Coal ash is the generic term referring to several very distinct materials produced when we combust coal to produce electricity. Coal ash offers our society extraordinary environmental and economic benefits without harm to public health and safety when properly managed.

Our industry refers to these materials as “coal combustion products” or “CCPs” to emphasize that they have significant commercial value. A multibillion-dollar industry has arisen over the past 50-plus years around the use of these materials, which include fly ash, bottom ash, boiler slag, and various forms of flue gas emission control/ desulfurization materials. Each of these varies by coal source and composition, combustion technologies, emissions controls technologies, and other factors.

In 2007, the United States produced 131 million tons of coal combustion products. While 43 percent were used beneficially, nearly 75 million tons were disposed of. By using coal ash instead of disposing of it in landfills we are avoiding the environmental degradation and energy costs associated with mining virgin materials. We are building stronger, longer-lasting structures that save taxpayer dollars and minimize environmental impacts. For every ton of fly ash used in place of portland cement about a ton of carbon dioxide is prevented from entering the Earth’s atmosphere. Also, it takes the equivalent of 55 gallons of oil to produce a single ton of cement.

Another significant benefit of using fly ash is that it requires less water than portland cement, conserving a limited resource, while also reducing a project’s water and equipment costs. Boiler slag, which replaces sand in blasting grit, has the benefit of being free of silica, which eliminates the potential health risk of silicosis. Flue gas desulfurization materials are used in 30 percent of U.S. wallboard products, avoiding the need to mine gypsum. Environmentally and economically it makes more sense to use existing materials than to mine new ones.

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