SEPA

Office of Resource Conservation and Recovery

EPA 530-F-23-004
June 2023

Fact Sheet: Coal Ash

What is Coal Ash?

Coal ash, also referred to as coal combustion
residuals or CCR, is produced primarily from the
burning of coal in coal-fired power plants. Coal
ash includes a number of by-products produced
from burning coal, including:

•	Fly ash, a very fine, powdery material
composed mostly of silica made from the
burning of finely ground coal in a boiler.

•	Bottom ash, a coarse angular ash particle
that is too large to be carried up into the
smokestacks, so it forms in the bottom of
the coal furnace.

•	Boiler slag, molten bottom ash from slag
tap and cyclone type furnaces that turns
into pellets with a smooth glassy
appearance after it is cooled with water.

•	Flue gas desulfurization material, a material
left over from the process of reducing sulfur
dioxide emissions from a coal-fired boiler
that can be a wet sludge consisting of
calcium sulfite or calcium sulfate or a dry
powdered material that is a mixture of
sulfites and sulfates.

Other types of by-products are:

•	fluidized bed combustion ash,

•	cenospheres, and

•	scrubber residues.

What do Power Plants do with Coal
Ash?

Coal ash is disposed of or used in different ways
depending on:

•	The type of by-product.

•	The processes at the piant.

•	The regulations the power plant must
follow.

Some power plants may dispose of coal ash in
surface impoundments or in landfills. Others
may discharge it into a nearby waterway under
the plant's water discharge permit. Coal ash
may also be recycled into products like concrete
or wallboard.

I

Surface impoundment at a coal-fired power
plant.

Why does EPA Regulate Coal Ash?

Coal ash contains contaminants like mercury,
cadmium, and arsenic. Without proper
management, these contaminants can pollute
waterways, ground water, drinking water, and
the air.

The need for federal action was highlighted by
large coal ash spills near Kingston, Tennessee
and Eden, North Carolina, which caused

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widespread environmental and economic
damage to nearby waterways and properties.

To address the risks from improper disposal and
discharge of coal ash, EPA established national
rules for coal ash disposal and strengthened
existing controls on water discharges.

EPA Coal Ash Regulations

EPA published a final rule on April 17, 2015. This
ruie finalized national regulations to provide a
comprehensive set of requirements for the safe
disposal of coal ash from coal-fired power
plants.

The final rule is the culmination of extensive
study of the effects of coal ash on the
environment and public health. The ruie
establishes technical requirements for coal ash
landfills and surface impoundments under
subtitle D of the Resource Conservation and
Recovery Act, the nation's primary law for
regulating solid waste.

Landfill at a coal-fired power plant.

Where Can I Find More
Information?

1.	Learn about coal ash:

www.epa.gov/coalash.

2.	Read about our rulemakings:

https://www.epa.gov/coalash/coal-ash-
rule.

3.	For press inquiries, contact:

press@epa.gov.

These regulations address the risks from coal
ash disposal -- leaking of contaminants into
ground water, blowing of contaminants into the
air as dust, and the failure of coal ash surface
impoundments. Additionally, the rule sets out
recordkeeping and reporting requirements as
well as the requirement for each facility to
establish and post specific information to a
publicly accessible website. This final rule also
supports the responsible recycling of coal ash
by distinguishing safe, beneficial use from
disposal.

Since 2015, EPA proposed and finalized changes
to the federal coal ash regulations to address
matters raised in litigation, legislation, petitions
for reconsideration, and implementation.

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