Understanding Coal Ash: Risks, Impacts, and Management
Coal ash is a toxic byproduct of energy generation, threatening human health, ecosystems, and water safety nationwide.
What Is Coal Ash?
Coal ash—also known as coal combustion residuals (CCR)—is the mineral residue left after burning coal for electricity production. Every year, coal-fired power plants in the United States generate tens of millions of tons of this waste, making it one of the nation’s largest industrial waste streams.
Coal ash can take several forms, primarily:
- Fly ash: Fine particles captured from flue gases by emission-control equipment.
- Bottom ash: Heavier particles that settle to the bottom of the boiler.
- Boiler slag: Molten bottom ash that forms pellets or granules.
- Flue gas desulfurization (FGD) materials: Byproducts from removing sulfur dioxide from power plant emissions, often a wet synthetic gypsum.
Combined, these forms of coal ash present serious challenges due to their toxic composition and immense volume.
Coal Ash Composition: What’s Inside?
Coal ash is laden with a complex mixture of potentially hazardous substances. Common toxic ingredients found in coal ash include:
- Arsenic
- Lead
- Mercury
- Selenium
- Cadmium
- Chromium
- Boron, manganese, lithium, molybdenum, cobalt, and thallium
Many of these metals are dangerous even in very small quantities. Their form and concentration in ash are determined by the original coal burned and the specific combustion process. As coal is combusted, these toxic elements become more concentrated, and without proper safeguards, can readily escape the containment measures put in place.
How Is Coal Ash Stored and Managed?
Coal ash is usually stored in two main ways:
- Surface impoundments (“ash ponds”): Large, manmade ponds or lagoons, frequently created by damming valleys or by constructing embankments, where wet coal ash slurry is deposited.
- Landfills: Dry storage of coal ash in piles or contained cells, often in proximity to the power plant.
Unfortunately, many of these storage sites lack modern engineering safeguards. Unlined impoundments allow water contaminated with toxic elements from the ash to seep into the underlying soil, groundwater, and eventually nearby rivers and lakes. Ash stored as a dry powder can also become airborne and spread to surrounding communities, affecting air quality and public health.
Key Risks of Coal Ash
| Risk | Description |
|---|---|
| Drinking water contamination | Toxic substances like arsenic, lead, or mercury can leach into groundwater or surface water, reaching drinking water supplies. |
| Air pollution | Fine, powdery coal ash dust can be lifted by wind into nearby neighborhoods, causing respiratory and cardiovascular issues. |
| Catastrophic releases | Failure or collapse of ash pond dams can release millions of gallons of sludge, devastating towns and ecosystems. |
| Soil and ecosystem contamination | Persistent toxins accumulate in soils and sediments, entering food chains, harming wildlife, and degrading habitats. |
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Health Effects on People and Communities
People living near coal ash disposal sites are at risk of exposure to harmful substances through drinking water, air, soil, or food. Direct health effects of coal ash exposure include:
- Cancer: Substances like arsenic and hexavalent chromium are carcinogenic.
- Neurological and developmental effects: Mercury and lead can impact childhood brain development and adult neurological function.
- Cardiovascular issues: Multiple toxins in coal ash are linked to heart disease.
- Kidney and liver damage: Chronic exposure to heavy metals can severely impair organ function.
- Respiratory problems: Inhaling fine ash dust can worsen asthma, bronchitis, and other lung diseases.
Children, pregnant women, the elderly, and those with pre-existing health conditions are especially vulnerable to coal ash’s health effects.
Environmental Impacts of Coal Ash Disposal
Coal ash pollution is not contained to site boundaries. Its toxic constituents migrate, impacting ecosystems and wildlife over wide areas. Environmental consequences include:
- Aquatic toxicity: Toxic runoff can devastate fish and aquatic invertebrates, harm amphibians, and cause declines of species in rivers and lakes.
- Bioaccumulation in food chains: Birds and mammals eat contaminated plants or fish, leading to reproductive problems, deformities, and population declines.
- Soil degradation: Heavy metals accumulate in soils, reducing fertility and killing beneficial microbes and plants.
Examples of Coal Ash Disasters
- Kingston, Tennessee (2008): An impoundment at the Tennessee Valley Authority’s Kingston Fossil Plant failed, releasing more than a billion gallons of coal ash slurry. The torrent covered over 300 acres, destroyed dozens of homes, ruined two rivers, and required massive, expensive cleanup.
- Eden, North Carolina (2014): A Duke Energy facility’s broken pipe released 39,000 tons of coal ash and 27 million gallons of contaminated water into the Dan River, polluting more than 70 miles of riverbed.
Because many impoundments are aging and under-regulated, the risk of such disasters remains a serious concern.
Current Regulation and Policy
After decades of advocacy, the U.S. Environmental Protection Agency (EPA) issued the Disposal of Coal Combustion Residuals from Electric Utilities final rule in December 2014. This rule established new federal requirements for coal ash disposal, such as:
- Location restrictions for new impoundments
- Groundwater monitoring and public disclosure
- Structural integrity criteria for dams
- Liner installation requirements for new units
- Mandatory closure or upgrading of unlined, leaking, or dangerous surface impoundments
However, the EPA did not classify coal ash as “hazardous waste” under the Resource Conservation and Recovery Act (RCRA). This decision means waste is regulated as “solid waste,” and primary enforcement is left to the states and facility owners. As a result, oversight and protections vary widely across the country, and environmental groups argue these standards still leave communities at risk.
Recycling and Reuse of Coal Ash
Efforts to reduce the burden of coal ash disposal include beneficial reuse. Fly ash and other coal ash types are used as raw materials in:
- Portland cement and concrete
- Wallboard and building materials
- Road base and embankment fill
Reuse can reduce the amount of ash requiring landfill or impoundment storage, but care must be taken to prevent exposure to leachable toxins in reused materials. Regulatory standards for such uses are less strict than for disposal.
Ongoing Challenges and Community Impact
Despite federal and state rules, coal ash problems persist:
- Weak and inconsistent enforcement: Many states lack stringent oversight; citizen lawsuits are often needed to force cleanup or upgrades of facilities.
- Environmental justice concerns: Disposal sites are disproportionately located near low-income or minority communities already burdened by industrial pollution.
- Legacy contamination: Older, unlined impoundments have leached toxins over decades, contaminating aquifers and rivers even where plants have closed.
To protect against ongoing harm, environmental advocates argue for:
- Federal enforcement of strong, uniform standards
- Comprehensive cleanup of legacy and leaking sites
- Involvement of affected communities in decision-making
Frequently Asked Questions (FAQs)
Q: What is coal ash and where does it come from?
A: Coal ash, or coal combustion residuals (CCR), is the waste produced from burning coal for electricity, mainly at coal-fired power plants.
Q: Why is coal ash considered dangerous?
A: It contains toxic heavy metals and chemicals such as arsenic, lead, mercury, and chromium, which pose serious human health and environmental risks.
Q: How does coal ash impact human health?
A: Exposure to coal ash contaminants is linked with cancer, neurological harm, respiratory illnesses, and cardiovascular problems.
Q: How is coal ash regulated in the United States?
A: Coal ash is regulated as solid waste under the EPA’s 2014 rule, which sets standards for storage, monitoring, and closure, but leaves much enforcement to states and facility owners.
Q: Can coal ash be recycled or reused safely?
A: Some coal ash can be reused in construction materials like concrete, but strict standards must be maintained to prevent toxic leaching or airborne exposure.
Q: What remains to be done to address coal ash risks?
A: Experts call for stricter regulation, consistent enforcement, remediation of old and leaky sites, and more community engagement in decisions about storage and cleanups.
Final Thoughts
Coal ash pollution represents an ongoing environmental and public health crisis. While recent reforms have improved management in some areas, the legacy of contamination and gaps in oversight continue to affect communities, water systems, and ecosystems. Addressing these challenges requires dedicated enforcement, resources for cleanup, and comprehensive involvement of affected people to ensure a safer future for all.
References
- http://www.southeastcoalash.org/about-coal-ash/
- https://en.wikipedia.org/wiki/Health_effects_of_coal_ash
- https://www.epa.gov/enforcement/national-enforcement-and-compliance-initiative-protecting-communities-coal-ash
- https://stateimpactcenter.org/issues/toxics/coal-ash
- https://www.epa.gov/coal-combustion-residuals/coal-combustion-residuals-ccr-basics
- https://www.catawbariverkeeper.org/coal-ash
- https://www.iaenvironment.org/newsroom/council-news/new-iec-report-highlights-health-and-environmental-impacts-of-coal-ash-pollution-in-iowa
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