Coal Ash

Coal ash can contain particulates (a mixture of solid particles and liquid droplets found in the air), volatile and semi-volatile organic compounds, and heavy metals.

These chemical compounds can cause skin irritation (dermatitis). Inhalation (breathing in) of these compounds can cause respiratory irritation and irritation of the eyes, nose, and throat. Ingestion (eating or swallowing) of these compounds can cause nausea, vomiting, and diarrhea. Some of the compounds found in coal ash can cause cancer after continued long-term ingestion and inhalation.

When a natural disaster occurs, contamination from coal ash can affect drinking water systems. Public water systems monitor and control for these types of contaminants. Private well owners should contact their local public health authority to find out if they should test their wells for these contaminants.

Coal ash is produced mainly from burning coal in coal-fired power plants. Two main by-products of coal ash combustion (the process of burning it) result from coal-fired operations:

  • Fly ash is a very fine, powdery residue from coal-fired plants (like factories). Fly ash is captured in the stack. Onsite coal ash ponds should mainly consist of fly ash, which is made up of heavy metals (for example, mercury, arsenic, copper, and chromium). Fly ash may pose an inhalation hazard when dry. Dry fly ash can cause respiratory irritation similar to flu-like symptoms.
  • Bottom ash is a heavier, coarse material captured at the bottom of the coal furnace. Bottom ash can contain cresol and semivolatile organic compounds such as polycyclic aromatic hydrocarbons. Bottom ash is unlikely to be in coal ash ponds because it is typically disposed of immediately after combustion and sent to a landfill.

The U.S. Environmental Protection Agency regulates coal ash under the Resource Conservation and Recovery Actexternal icon (RCRA) and the Clean Water Act. RCRA regulates management of hazardous and nonhazardous solid waste in the United States.

To learn more about coal ash and how EPA regulates it, visit here: icon

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Page last reviewed: October 15, 2018