Who gains from saving nature
Ledger 1 : 33 — For each dollar financing nature-based solutions in 2023, about $33 financed activities harmful to nature. (UNEP)
Cases / Chemical pollution · United States · 2015–2026

US coal ash ponds, groundwater contamination and EPA delay

Nature's voice · report
No measurement of the harm done to me here is on record.
Did nature suffer? Not measured. Disputed
What the record lacks: 2 none on record · 1 not measured · 2 disputed See the gaps
Accounts of the harm differ
Is most US coal ash put to beneficial use?
  • Company or project American Coal Ash Association: Its survey reported a beneficial use rate of 72% in 2024. Concrete Products
  • Government and regulators US Environmental Protection Agency: Its page states that a 12,400-ton threshold applies only to non-encapsulated fill that is not on a road, and that the definition was being reconsidered. US Environmental Protection Agency
  • Communities and civil society Earthjustice and Environmental Integrity Project: 265 of 292 plants with coal ash ponds were contaminating groundwater. Earthjustice

A 2022 report found that 91% of US power plants with coal ash ponds were contaminating groundwater. In February 2026 the deadline for groundwater monitoring at such sites was reported extended to 2031.

91% (265 of 292)US power plants with coal ash ponds contaminating groundwater, 2022
Only 4% (11 plants) chose a cleanup plan that includes treatment (Earthjustice and Environmental Integrity Project report, November 2022).

Status As of February 2026: groundwater monitoring period extended to 2031; Duke Energy insurer case settled in 2021; no ruling on Puerto Rico ash found.

What?
Coal ash ponds at US power plants were found to contaminate groundwater, and the EPA extended the groundwater monitoring period to 2031. Earthjustice
Where?
United States; North Carolina; Guayama, Puerto Rico. Earthjustice
When?
2015 to 2026; report November 2022; monitoring extension February 2026. Earthjustice
Who?
Gained
  • Duke Energy — Earns a return on the cleanup cost passed to customers Utility Dive
Lost
  • Duke Energy customers — Bore most of the $8–9 billion cleanup cost Utility Dive
Harmed
  • Groundwater at 265 of 292 plants; groundwater near Guayama, Puerto Rico — Contamination; arsenic more than twice the standard near Guayama Canary Media
Why?
Not stated in the sources reviewed beyond the account that ash was stored in ponds and sold or used as fill.
How?
Ash stored in ponds leaked into groundwater; ash was also placed as fill, in Puerto Rico without records. Earthjustice
6 of 6 questions answered from the record

What happened

The record, in order.

A November 2022 report by the Environmental Integrity Project and Earthjustice found that 265 of 292 US power plants with coal ash ponds, 91%, were contaminating groundwater. Only 11 plants, 4%, had chosen a cleanup plan that included treatment.

In February 2026 Earthjustice reported that the Environmental Protection Agency had extended the groundwater monitoring period by 33 months, to 2031, ahead of a larger rollback of the coal ash rules.

The coal ash industry association reported that 72% of the 63.6 million short tons of coal ash produced in 2024 was put to beneficial use. An EPA page says its 12,400-ton threshold applies only to non-encapsulated fill that is not on a road, and that the definition was being reconsidered.

In Puerto Rico, Canary Media reported that ash from the AES plant was sold as fill around Guayama after the Dominican Republic refused it, that no record was kept of where it went, and that ash distributed in this way was exempt from the rule. The company's own groundwater measurements showed arsenic at more than twice the standard.

In North Carolina, Duke Energy's coal ash cleanup was put at $8–9 billion. Utility Dive reported that most of the cost fell to customers and that Duke continued to earn a return on it. A January 2021 settlement with the state attorney general included an additional $100 million penalty. Separately, Duke sued about 30 insurers in 2017 over its coal ash liability and received about $418 million in settlements by August 2021.

  1. 201729 March: Duke Energy sues about 30 insurers in North Carolina Business Court over coal ash liability
  2. 2021January: settlement between the North Carolina attorney general and Duke Energy; August: last of 14 insurer settlements
  3. 2022November: report finds 91% of plants with ash ponds contaminate groundwater
  4. 202463.6 million short tons of coal ash produced; industry survey reports 72% beneficially used (published 2025)
  5. 2026February: groundwater monitoring period extended by 33 months, to 2031

What was said

Claims, in the words of those who made them.

Where accounts differ

Each party's account, side by side, with its source. The record does not settle these points; it shows them.

Is most US coal ash put to beneficial use?
Company or project
American Coal Ash Association

Its survey reported a beneficial use rate of 72% in 2024.

Concrete Products
Government and regulators
US Environmental Protection Agency

Its page states that a 12,400-ton threshold applies only to non-encapsulated fill that is not on a road, and that the definition was being reconsidered.

US Environmental Protection Agency
Communities and civil society
Earthjustice and Environmental Integrity Project

265 of 292 plants with coal ash ponds were contaminating groundwater.

Earthjustice
Did Duke Energy's insurers owe cover for coal ash liability?
Company or project
Duke Energy

Sued about 30 insurers in March 2017 under 57 general liability policies from the early 1970s to the mid-1980s, with a liability estimate of $5.1 billion.

North Carolina Department of Justice
Company or project
Insurers

Said the damage "was caused intentionally, by or at Duke's direction", that "Duke continued to dispose of (coal ash) in unlined ash ponds long after it knew it had environmental problems", that there was no distinct pollution event ("occurrence"), and that Duke had made claims for the same ponds in the 1990s.

North Carolina Department of Justice
Courts
Chief Judge Bledsoe, North Carolina Business Court

Found at summary judgment that the insurers had not proved intentional damage at the Mayo plant, and ruled that "all sums" allocation applies to TIG and Ranger.

North Carolina Department of Justice

How it looked

What was shown, beside what was recorded.

Shown

  • 72% of coal ash in the United States put to "beneficial use" in 2024
    American Coal Ash Association survey, as reported by Concrete Products · Concrete Products

Recorded

  • 265 of 292 power plants with coal ash ponds contaminating groundwater (91%); 11 plants (4%) chose a cleanup plan with treatment (2022)
    Earthjustice
  • Groundwater monitoring period extended by 33 months, to 2031 (February 2026)
    Earthjustice
  • Ash sold as fill in Puerto Rico; no record kept; company measurements showed arsenic in groundwater at more than twice the standard
    Canary Media
  • Duke Energy cleanup plan of $8–9 billion; most of the cost passed to customers; Duke earns a return
    Utility Dive

Who gained

Money that reached nature, beside money that stayed elsewhere.

Reached nature or the ground

Not published
No figure published.

Gained elsewhere

Not totalled
Currency: USD · Window: . All figures cover the same period. * Estimate built from cited figures.

Responses on record

  • american-coal-ash-association (2025): Reported through its survey that 72% of coal ash produced in 2024 was beneficially used. · Concrete Products

In court and with insurers

Every proceeding and every insurer decision on record.

Lawsuits and rulings

  1. 2017-03-29–2021-08Settled$418m USD million received in settlements
    Duke Energy v. about 30 insurers (coal ash liability cover)
    North Carolina Business Court · Civil · Duke Energy → About 30 insurers

    Duke sued over 57 general liability policies from the early 1970s to the mid-1980s. Liability was estimated at $5.1 billion, with more than $725 million spent by November 2016. There were 14 settlements with 23 insurers, the last in August 2021. Two foreign insurers defaulted. North Carolina Department of Justice

  2. 2021-01Settled$100m USD million additional penalty
    North Carolina Attorney General settlement with Duke Energy on coal ash cleanup
    State of North Carolina · Regulatory · North Carolina Attorney General → Duke Energy

    Utility Dive reported a cleanup plan of $8–9 billion, with write-offs of $485 million and $270 million and a further $100 million penalty. The consumer group NCLCV reported a saving of $1.1 billion for customers. Utility Dive

Insurers

  1. 2021Partly paid$418m USD million received in settlements
    About 30 insurers → Duke Energy
    Stated reason: Insurers argued the damage was intentional, that there was no distinct occurrence, and that Duke had made claims on the same ponds in the 1990s.

    14 settlements with 23 insurers, the last in August 2021. Two foreign insurers defaulted. North Carolina Department of Justice

What nature saw

Outcomes measured on the ground, and nature's note.

Nature's report opens this page. Below: further outcomes measured on the ground.

Plants contaminating groundwater
91% (265 of 292)
US plants with coal ash ponds, 2022
Plants with a treatment-based cleanup plan
4% (11)
2022
Groundwater arsenic near Guayama, Puerto Rico
More than twice the standard
The company's own measurement (Canary Media)

What we don't know

Undisclosed, unproven, untried: recorded as data.
Court ruling exists

Nature

  • Not measured Harm to nature: The record holds no measurement of harm to nature.
  • Disputed Is most US coal ash put to beneficial use?

Accounts

  • Disputed Did Duke Energy's insurers owe cover for coal ash liability?

Record

  • None on record Where the ash sold as fill around Guayama, Puerto Rico, went: no record was kept (Canary Media).
  • None on record The EPA's definition of beneficial use was being reconsidered, according to the agency's own page.

Did the harm stop?

The sources reviewed do not say that groundwater contamination at the plants has stopped. In February 2026 the monitoring period was reported extended to 2031.

Who paid?

Utility Dive reported that most of Duke Energy's $8–9 billion cleanup cost fell to customers. A consumer group said the settlement saved customers $1.1 billion.

Sources

Voices on record: — Company or project✓ Government and regulators— Courts✓ Press and investigations✓ Communities and civil society— Researchers

Government and regulators

  1. Frequent Questions about the Beneficial Use of Coal Ash
    US Environmental Protection Agency · 2015/2025

Press and investigations

Communities and civil society

Connected cases

Related matters, and cases linked to this one through the same organisations, with the role each played in both.
Terms used on this page

Science and environment

Groundwater
Water held underground in soil and rock, drawn through wells.
PFOA (C8) and PFAS
PFAS are a large family of human-made chemicals that persist in the environment and the body; PFOA, also called C8, is one of them and was used to make Teflon.

Institutions

EPA
The US Environmental Protection Agency.
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