All About Coal Ash: What is it and why is it dangerous

By Franz Raetzer

Coal-fire plants, such as the Kingston, TN plant create coal ash as a byproduct of burning coal. The chemical elements in coal in sufficient quantity can exceed maximum health standard limits by up to 2000 times.

What is coal ash?

Coal ash is created when we burn coal and consists of the concentrated pollutants. Some pollutants are airborne in the smoke and collected with filters or scrubbers and so prevented from going out of the smokestacks into the environment. But these pollutants need to be cleaned out of the ash pit (ash, clinker, slag), the boiler (soot), the chimney and scrubbers (fly ash). All these parts of coal combustion waste (CCW) are commonly called Coal Ash and are extremely toxic. They contain about 20 chemical elements (mercury, arsenic, chrome, selenium, etc.) in sufficient quantity to exceed the maximum limits set in the health standards for these elements by up to 2000 times. Unfortunately, the Environmental Protection Agency (EPA) has not classified CCWs as toxic because they assume that any (beneficial) use of CCWs will involve dilution (mixing with concrete, sand, water, etc.). The dilution with river water is very problematic, because anaerobic bacteria in the sediments produce conditions that reduce arsenic from the common pentavalent form to the more-toxic trivalent form. Selenium leaches out of these anoxic (oxygen-less) sediments and migrates to the surface water, where it can be sucked-in into the water treatment plant of utilities, which do not have the means to remove the arsenic as well as other atomic elements like chrome.

Storage of CCWs

Coal ash used to be stored in heaps or mounds (like gravel) on the ground without berms and liners to prevent run-off or leachate into the ground water. The old Gallatin coal ash mountain has no liner or berms and it is close to a river. Today, CCW should be in a landfill build for CCW storage. It should built on solid ground, preferably solid bedrock without cracks or cavities. The ground should be smooth and flat. There should not be any sharp peaks or edges that could damage the liner. A water-proof liner and leachate collecting system should be installed. An earthquake-proof dam should surround the landfill with the liner going to the crest of the dam. To consider is that coal-ash will liquefy during an earthquake or a dam break (as in Kingston in 2008). When the landfill is full, it should be capped with a waterproof cap and layer of agricultural soil and grass grown.

An example of the devastation wrought by the 2008 Kingston coal ash spill (Photo by Ann League)

What effect has coal ash on the environment?

Because of the vast variety of elemental components and the large amounts, usually measured in parts per billion (ppb), coal ash is very toxic when it gets into the environment or comes into contact with humans or wildlife. It can enter any life form via breathing, skin contact, or ingestion.

What negative health effects is coal ash causing?

Coal ash can cause a multitude of illnesses: asthma, blood-, skin-, nerve system-, various organ- and brain-illnesses and promote cancers. Because of these many health effects it is very important that coal ash is stored properly for eternity. Many of the elemental components can leach out of coal ash for centuries. Some will even be harmful when oxidized (building a molecule with oxygen).

Learn More

Coal ash is a dangerous and ever-present threat to communities surrounding coal-fire plants. If you would like to learn more about coal ash and how communities have dealt with it, come to SOCM and Working Film’s joint screening of Coal Ash Stories in Gallatin, TN. 

Leave a Reply

Your email address will not be published. Required fields are marked *