Over one hundred new reports released on Illinois’ coal ash: What have we learned?

We are finally seeing the results of many years of rulemaking on the problem of coal ash.

Following the 2008 TVA Kingston disaster that spilled a billion gallons of coal ash, destroying property and the environment, the US EPA began drafting rules governing the disposal of coal ash. Coal ash is a waste product produced by coal-fired powerplants. It contains many heavy metals like mercury, arsenic, selenium, chromium and cadmium. These contaminants are persistent in the environment and dangerous to people and wildlife. Currently, coal ash is stored in impoundments, which are elevated ponds surrounded by large man-made dams of earth. Many of these impoundments store millions of cubic yards of coal ash (we like to measure them in terms of equivalent volumes of Empire State Buildings).

The result of the US EPA’s rulemaking is commonly known as the Federal Coal Combustion Residual Rule (CCR Rule) and it went into effect in 2015. Across the nation, the CCR Rule requires coal ash impoundment operators to periodically release reports for each coal ash impoundment they operate. The latest round of reports came out on November 16th, 2016, and the material covered includes:

  • How Illinois’ coal ash impoundments be closed.
  • What the hazard potential is at these coal ash impoundments.
  • The likelihood that an impoundment will fail.
  • How many coal ash impoundments are lined.

Illinois has 25 major coal-fired power plants, which have a total of over 80 coal ash impoundments on their collective sites. The November 2016 round of reporting released at least 168 documents to the public, with even more documentation missing.

The burden of reviewing these documents has landed in the laps of groups like Prairie Rivers Network. The federal CCR Rule is ‘self implementing’, which means that the coal ash operators release the documents and the public is responsible for reviewing them and, if necessary, leveraging lawsuits to protect themselves and the environment. There is no government oversight. Prairie Rivers Network has gone through the trouble of collecting and reviewing many of these documents, but this daunting task is a work in progress.

Here, we summarize what we have learned so far. While reading, it may be useful to have our coal ash map open in another window.

But first; what’s missing?

Before we dive into what we’ve learned, it’s important to first discuss what is missing. This may be the real story. The 168 documents that we have collected do not represent the entirety of what was supposed to be released. For example, in some locations, entire impoundments are completely undocumented.

The following table highlights the documents that are missing for each impoundment (that we know of). All of the documents in the table should have been made available on November 16th 2016.(1)

Table 1. Missing documentation from the November 16th reporting deadline of the CCR Rule.

Missing documents from the November 16th reporting deadline of the CCR Rule.

Documents are missing at coal ash sites throughout the state. The impoundments that are missing ALL documentation, such as the Secondary and Tertiary Pond at Dynegy’s Baldwin which were mentioned in a report from February 2016 but not in the November 2016 documents. These impoundments may be exempt for one reason or another, but no exemption was discussed in the documents released. Other missing documents, such as the single missing hazard potential report for the Bottom Ash Basin at Dynegy’s Duck Creek, could simply be mistakenly not uploaded to Dynegy’s webpages. Perhaps the most strange are the impoundments which have some but not all of the documentation, such as the South Ash Ponds 2S and 3S at Will County Station. Why only produce half of the required documents? Prairie State Generation requires a log-in to view their publicly-available documents, but their log-in system is down and their technical support is ignoring our requests. They are legally obligated to make this information available (Edit: Prairie State Generation provided me with a log-in, and these documents are not missing).

The critical point here is these documents are missing because no one has forced the coal ash operators to produce them.  The CCR Rule relies on the public to bring lawsuits for enforcement. This leaves a tremendous burden on the public to ensure that a coal ash operators, usually for-profit entities, are protecting local communities and the water resources those communities depend on. It seems unlikely that any individual person or group has the capacity to sue the coal ash operators over missing documents, yet the information contained within those documents could be crucially important. This is a fundamental flaw in the CCR Rule! Publicly releasing the documents is important, but in the absence of a governing body with legal power overseeing the process, reporting deadlines are potentially meaningless. As if to demonstrate the point, at Southern Illinois Power Cooperative’s Marion Power Station there are 12 coal ash impoundments but only one of those impoundments is documented!

quoteInformation at Closed Facilities: The other major source of missing documentation was cooked right into the CCR Rule. The federal CCR Rule only applies at powerplants that were operating when the rule was implemented. There were 7 coal fired powerplants in Illinois with coal ash impoundments that were closed at that time, with at least 17 coal ash impoundments between them. Coal ash impoundments at those sites are exempt from the CCR Rule, which means we will not get groundwater reporting, structural stability assessment, hazard potential, liner status, or construction histories at these sites. These impoundments at closed facilities pose the same risks as the impoundments at operating plants and their exclusion is a critical gap.

Now, onto what we have learned from the documents that were released.

How will Illinois’ coal ash impoundments be closed?

Why it matters: Closure will determine the fate of coal ash in Illinois. In general, there are two methods of closure: closure in place and removal of coal ash. Coal ash impoundments that are closed in place are usually capped and then left where they currently lie, often in floodplains of rivers or lakes. The alternative is removal of coal ash to a high, dry and lined location where it can be stored in a manner that does not damage groundwater or rivers. In some cases, removal can also be followed with reuse of the coal ash in another industrial process.

What we learned: The vast majority of coal ash impoundments in Illinois will be closed in place.

Dynegy, the owner of the largest number of ash impoundments, intends to close coal ash in place at every power plant they operate. A total of 19 impoundments are going to be closed in place according to the documents. For three other impoundments, Dynegy intends to remove and dispose of the ash, but they provide no details as to how they intend to dispose of it. Since they are closing ash impoundments at each of these sites, it’s possible they will just dump the ash into the other impoundments at the same site that they intend to close in place.

In what may be good news, another major coal ash operator called NRG Energy has chosen to close seven of their nine coal ash impoundments by removal. The ash at their sites will be removed and moved via trucks to either the Lincoln Stone Quarry at Joliet 9, a beneficial use site, or another permitted disposal facility. We will be looking to see that the transportation is done carefully, and the permitted disposal sites are genuinely safe places to store the ash. Most importantly, this demonstrates that closure by removal isn’t an unreasonable task, given that one company is willing to close the majority of their impoundments in this way. The two ash impoundments that will be closed in place are the Lincoln Stone Quarry at the Joliet 9 Station, and the Former Ash Basin at Powerton.

Springfield’s Dallman Station has two coal ash impoundments nestled between Lake Springfield and Sugar Creek. Despite known groundwater pollution impacts to Sugar Creek, they intend to close that ash in place.

What are the hazard potential risks at these coal ash impoundments?

Why it matters: Coal ash impoundments are almost always next to rivers or lakes, threatening wildlife habitat and environmental quality, but sometimes they are also perched above property and habitable areas. The CCR Rule requires coal ash operators to investigate the hazard potential for each impoundment they operate. The hazard potential is the risk that a failure would damage property, the environment, or cause loss of life.

The CCR Rule sets out three possible hazard potential ratings: low, significant and high. A high hazard potential impound is likely to cause loss of life in the event of a failure. A significant hazard potential impoundment is defined as a impoundment where failure will probably not result in loss of life, but will cause economic and environmental damage. A low hazard potential impoundment is defined as having a low probability to cause loss of life, and cause minimal economic loss.


What we learned: The majority of the impoundments that were rated in this round of reporting are rated as having significant hazard potential – posing minimal risk of loss of life, but likely to cause economic and environmental damage. There are four documented high hazard impoundments in Illinois: the GMF/Gypsum Stack Pond at Dynegy’s Coffeen Power Station, the Ash Pond at Dynegy’s E.D. Edwards Plant, the East Ash Pond System at Dynegy’s Havana, and the East Ash Pond at Dynegy’s Joppa.

Only two low hazard impoundments were identified, the Dallman and Lakeside Coal Ash Ponds at Springfield’s Dallman Power Station.

What is the likelihood that an impoundment will fail?

Why it matters: While the hazard potential evaluates the damage that would be caused by failure, the safety factors evaluate the risk of a failure occurring. Each coal ash impoundment must meet achieve or beat a minimum factor of safety for a number of potential loading conditions: long term loading, short term loading, and seismic loading. If an impoundment does not meet the factor of safety, then the level of risk is unacceptable, and this can trigger closure.

What we learned: All of the coal ash impoundments in Illinois achieved the minimum level of safety (but note that many of the impoundments were exempt from this reporting requirement for now). Table 2 highlights just the impoundments that met requirements by a margin of 10% or less for at least one loading.

Table 2. Impoundments in Illinois with safety factor ratings within 10% of the minimum rating, and the hazard potential for those impoundments.


Two ash ponds have the unfortunate condition of having both a high hazard rating and a narrow margin of passing the safety requirement, and those are the East Ash Pond at Joppa, and the Ash Pond at Edwards, both Dynegy facilities. Joppa’s East Ash Pond squeaks by with a seismic safety factor of 1.01, barely over the required 1.00.

Ash Pond No. 1 at Coffeen just barely met the safety requirement for the long term loading condition with a computed safety factor of 1.50, exactly meeting the minimum of 1.50. Exactly meeting the safety factor to the decimal point is suspicious enough to raise eyebrows. At many facilities, the computed long term and short term loading conditions have the same value(2). However, for this impoundment, the computed short term safety requirement is 1.49, and if the long term safety factor shared this value, it would fail to meet the minimum of 1.50, triggering shutdown. This is absolutely not hard evidence of any misconduct, but without documentation of the calculations, it does raise some suspicious.

Ash Pond No. 1 at Coffeen also has a historical record of sloughing. The image below is from a slough that occurred in 2015, and has been repaired. The Ash Pond at Edwards also has a record of surficial sliding, occurring twice in the same location in 2009. The East Ash Pond at Joppa had 8 separate surficial sliding events in 2011.

How many coal ash impoundments are lined?

Why it matters: An unlined coal ash impoundment is directly connected with the groundwater. Contaminants seep from the coal ash into the groundwater. The Illinois EPA has investigated groundwater at 22 coal ash sites across the state, and found contamination at all of them. A modern coal ash impoundment would require a liner which would prevent contaminated water in the impoundment from seeping into and polluting the groundwater. However, many of these impoundments were built well before liners were required, and therefore do not have a liner.

What we learned:
Many of the coal ash impoundments did not have to report on whether they had a liner or not, due to exemptions in the rule. However, we can see a general trend for the impoundments that did report on liners. The majority of Dynegy’s ponds are not lined, or unreported. All of NRG Energy’s impoundments are lined, or unreported. Springfield’s Dallman coal ash impoundments are not lined.

Closing Thoughts

One of the lessons learned from this round of reporting is that government oversight of the rule is important to get coal ash operators to properly document their waste storage. This revelation comes at an interesting time, as the recently passed Water Infrastructure Improvements for the Nation Act allows state environmental protection agencies, like our Illinois EPA, to take control of regulation of the ash. If the the Illinois EPA decides to pass their own coal ash regulations that are as protective as the federal rule, they would have a chance to take responsibility for enforcing the documentation of these impoundments. However, it is equally important that the documents are still released publicly. We want the public to be able to review this material, we just don’t feel like the public should be the only entity responsible for reviewing and enforcing these regulations.

As coal ash operators across Illinois begin to look toward impoundment closure, we may need these documents to help us convince coal ash operators to remove their waste from the banks of our rivers and lakes. We are going to need all the help we can get, especially if coal ash operators like Dynegy, a Texas based company, are planning on leaving all their coal ash messes exactly where they are, for Illinois’ future generations to deal with.


  1. Documents that were initially exempt from reporting requirements due to being active are not included in this list. Those impoundments now require reporting in the next 18 months. (^)
  2. The calculated safety factors for short term and long term conditions are the same at the following seven Dynegy impoundments: Bottom Ash Pond at Baldwin, Gypsum stack pond at Coffeen, Ash Pond at Edwards, East Ash Pond at Havana, East Ash Pond at Hennepin, Ash Pond at Kincaid, Primary Ash Pond at Newton.(^)

Staff Contact
Andrew Rehn, Water Resources Engineer, arehn @ prairierivers.org