Frequent Questions about the Beneficial Use of Coal Ash

EPA developed frequent questions about the beneficial use of coal combustion residuals relating to the final rule on disposal of CCR from electric utilities, implementing this final rule, and the evaluation of beneficial use of two types of CCR.

Beneficial Use under the Final CCR Disposal Rule

What is beneficial use?

Beneficial use is the recycling or reuse of coal ash in lieu of disposal. For example, coal ash is an important ingredient in the manufacture of concrete and wallboard (also known as drywall), and EPA supports the responsible use of coal ash in this manner. This final rule supports the responsible recycling of coal ash by distinguishing beneficial use from disposal.

Why do companies recycle and reuse coal ash?

Beneficial use of coal ash can produce positive environmental, economic and performance benefits such as reduced use of virgin resources, lower greenhouse gas emissions, reduced cost of coal ash disposal, and improved strength and durability of materials.

How is coal ash currently being beneficially used?

As of 2012, according to the American Coal Ash Association (ACAA) data, approximately 50 percent of the CCRs beneficially used on an annual basis falls into two categories:

fly ash used as a direct substitute for Portland cement during the production of concrete (referred to as "fly ash concrete"); and
FGD gypsum used as a replacement for mined gypsum in wallboard (referred to as "FGD gypsum wallboard") during use by the consumer.

Specifically, a 2012 ACAA survey indicates the largest encapsulated beneficial uses of CCRs, by more than a factor of two, are fly ash used in "concrete/concrete products/grout" (12.6 million tons) and FGD gypsum used in "gypsum panel products" (7.6 million tons).

How are beneficial uses of coal ash currently regulated?

Currently, state environmental agencies are primarily responsible for regulating beneficial use. Coal ash being beneficially used is currently excluded from federal regulation under EPA's May 2000 regulatory determination that the Bevill amendment applies to such uses. Under the Resource Conservation and Recovery Act (RCRA), federal action could be taken if there were a finding of imminent or substantial endangerment in a specific circumstance.

Does the final rule regulate beneficial use?

The final rule provides a definition of beneficial use to distinguish between beneficial use and disposal. This rule does not affect beneficial use applications completed before the effective date of the rule; only applications to be started after the effective date of the rule need to determine if they comply with the criteria contained in the final rule distinguishing between beneficial use and disposal.

Does the final rule define beneficial use of coal combustion residual?

The final beneficial use criteria are as follows: (1) The CCR must provide a functional benefit; (2) The CCR must substitute for the use of a virgin material, conserving natural resources that would otherwise need to be obtained through practices such as extraction; (3) The use of CCRs must meet relevant product specifications, regulatory standards, or design standards when available, and when such standards are not available, CCRs are not used in excess quantities; and (4) When unencapsulated use of CCRs involves placement on the land of 12,400 tons or more in non-roadway applications, the user must demonstrate and keep records, and provide such documentation upon request, that environmental releases to ground water, surface water, soil and air are comparable to or lower than those from analogous products made without CCRs, or that environmental releases to ground water, surface water, soil and air will be at or below relevant regulatory and health-based benchmarks for human and ecological receptors during use.

What is structural fill?

Structural fill is typically an earthen material used to create a strong, stable base. Structural fills are constructed by compacting earthen material to develop a structural fill that can be used to support roadways or other structures when completed. Traditionally, fill materials have been composed of soil and natural aggregates. However, coal combustion residuals can be used as a substitute for natural materials in the construction of a structural fill.

Does the final rule regulate structural fill?

The final rule provides a distinction between disposal and beneficial use. In the final rule, a definition of the term "beneficial use of coal combustion residual" is provided. The definition contains four criterion that unencapsulated uses of CCRs (like structural fills) must comply with. The fourth criterion applies to any unencapsulated use of CCRs that involves placement on the land of 12,400 tons or more in non-roadway applications. If a non-roadway structural fill application, larger than 12,400 tons, complies with all four criterion, then the structural fill application is considered beneficial use. Any non-roadway structural fill application larger than 12,400 tons, that fails to comply with all of the relevant criteria in the definition of "beneficial use of CCR" will be considered disposal of CCRs subject to all of the requirements in the disposal regulation.

Beneficial Use and Implementing the Final CCR Disposal Rule

EPA has received many questions on implementing the final CCR disposal rule. The Agency is developing responses to these questions and will be posting new ones periodically.

These questions will cover topics including piles of CCR awaiting beneficial use, applications of CCR (such as flowable fill and agricultural uses), and the demonstration and documentation aspects of the beneficial use definition in the rule.

General Questions

How does the CCR rule impact CCR that are beneficially used?

The CCR final rule retains the Bevill Determination without revising it and does not regulate CCR that are beneficially used. The rule provides criteria that support and encourage the appropriate beneficial use of CCR. The rule clarifies that a use of a CCR that does not meet the definition and criteria of a beneficial use is disposal.

How will EPA work with state beneficial use programs and/or end users or generators of byproducts regarding interpreting the beneficial use criteria? Secondly, will EPA review evaluations of the criteria or offer opinions?

EPA can provide assistance to state beneficial use programs and end users about how to interpret the beneficial use criteria. The Agency is working to provide tools to assist states and beneficial users with their beneficial use evaluations. EPA does not review or approve evaluations of the criteria conducted by others.

Where can the "Engineering and Environmental Guidance on the Beneficial Use of Coal Combustion Products in Engineered Structural Fill Projects" be obtained?

The Utility Solid Waste Activities Group (USWAG) document, “Engineering and Environmental Guidance on the Beneficial Use of Coal Combustion Products in Engineered Structural Fill Projects," referenced in the preamble can be found in the docket to the rule.

The preamble to the rule mentions that EPA is developing a framework for assessing the risks associated with the beneficial use of unencapsulated CCR. When does the Agency anticipate completion of this framework?

During the development of the framework to address the risks associated with the beneficial use of unencapsulated materials including CCR, the Agency determined that the principles outlined in the 2013 Methodology for Evaluating Encapsulated Beneficial Uses of Coal Combustion Residuals are also applicable and relevant to unencapsulated uses. Therefore, EPA combined the discussion of encapsulated and unencapsulated uses into a single document and renamed it the Methodology for Evaluating the Beneficial Use of Industrial Non-Hazardous Secondary Materials (BU Methodology) to reflect the broader scope.

CCR Piles

Would a facility that stores piles of flue gas desulfurization (FGD) gypsum on the ground for ultimate beneficial use as wallboard greater than the 12,400-ton CCR rule threshold have to meet the unencapsulated use requirements?

As EPA noted on pages 21347-21348 of the final rule, in order to be subject to RCRA, the material must be a solid waste. The statute defines a solid waste as "any garbage, refuse….and other discarded material…" title 42 of the U.S. Code section 6903 (27). As EPA noted in the proposed and final rule:

"For some beneficial uses, CCR is a raw material used as an ingredient in a manufacturing process that have never been ''discarded,'' and thus, would not be considered solid wastes under the existing RCRA regulations. For example, synthetic gypsum is a product of the FGD process at coal-fired power plants. In this case, the utility designs and operates its air pollution control devices to produce an optimal product, including the oxidation of the FGD to produce synthetic gypsum. In this example, after its production, the utility treats FGD as a valuable input into a production process, i.e., as a product, rather than as something that is intended to be discarded. Wallboard plants are sited in close proximity to power plants for access to raw material, with a considerable investment involved. Thus, FGD gypsum used for wallboard manufacture is a product rather than a waste or discarded material. This use and similar uses of CCR that meet product specifications would not be regulated under the final rule."

Note that whether the FGD gypsum is being managed as a "waste" or a "product" is a fact-specific determination. Indications that the FGD gypsum is being managed as a waste or a product by the utility include the rate at which the material is being used versus being added, and whether it is being managed as a valuable product (i.e., stored or protected in the same way virgin products are managed). For example, if more FGD gypsum is being added to a pile than can actually be used, and if the material is not being managed as a valuable product, then that would be an indication that it is it not being treated as a product; and would therefore be a "waste."

For those materials that are "wastes," a power-generating facility that stores piles of FGD on the ground on-site at the facility for ultimate beneficial use as wallboard greater than the 12,400-ton threshold would not have to meet the unencapsulated use requirements; however, the FGD piles must be "containerized" in order to not be considered a CCR Pile (and by definition, a CCR landfill). The use of the phrase "containerized" is not intended to require that all activities occur within tanks or containment structures, but merely that specific measures have been adopted to control exposures to human health and the environment. This could include placement of the CCR on an impervious base such as asphalt, concrete, or a geomembrane; leachate and run-off collection; and walls or wind barriers (refer to page 21356 of the final rule).

What if the facility storing the FGD on the ground is not an electric utility?

In this case, if the facility treats the FGD gypsum as a valuable input into a production process, i.e., as a product, rather than as something that is intended to be discarded, the use would not be regulated under the final rule (refer to the response above).

For those materials that are "wastes," FGD gypsum that is currently being used in compliance with the definition of beneficial use, including FGD gypsum stored in a temporary pile prior to being beneficially used, would not be subject to the CCR disposal regulations. As noted at volume 80 of the Federal Register (FR) 21356 in the final rule preamble,

"CCR that is currently being used beneficially—for example, fly ash that has been transferred to a cement manufacturer and that is stored off-site in a ''temporary pile,'' and that complies with all of the criteria in the definition to be considered a beneficial use including the fourth criterion relating to the placement of large quantities of unconsolidated CCR on the land— would not be subject to the regulations applicable to CCR disposal."

Although ultimately intended for encapsulated use in wallboard, a pile of FGD gypsum that is a "waste" is still considered an unencapsulated CCR until it is actually incorporated into the wallboard; therefore, if the amount of FGD gypsum in a pile awaiting beneficial use exceeds 12,400 tons, the facility also must comply with the fourth criterion pertaining to unencapsulated non-roadway uses. One way to ensure the fourth criterion is met is to containerize the pile; that is, adopt specific measures to control exposures to human health and the environment, such as placement of FGD gypsum on an impervious base, such as asphalt, concrete, or a geomembrane; leachate and run-off collection; and/or use of walls or wind barriers.

EPA's Efforts in Evaluating Beneficial Uses of CCR

What is "encapsulated beneficial use" of CCR?

EPA defined "beneficial use" as the reuse of CCR in a product that:

provides a functional benefit.
replaces a product made from virgin materials on the market, which conserves natural resources that would otherwise need to be obtained through practices, such as extraction.
meets relevant product specifications and regulatory standards.

An encapsulated beneficial use is one that binds the CCR into a solid matrix that minimizes their mobilization into the surrounding environment. Examples of encapsulated uses include, but are not limited to:

Filler or lightweight aggregate in concrete.
A replacement for, or raw material used in production of, cementitious components in concrete or bricks.
Filler in plastics, rubber, and similar products.
Raw material in wallboard production.

What is "unencapsulated beneficial use" of CCR?

Like the encapsulated beneficial use of CCR, the unencapsulated beneficial use of CCR:

provides a functional benefit.
replaces a product made from virgin raw materials on the market, which conserves natural resources that would otherwise need to be obtained through practices, such as extraction.
meets relevant product specifications and regulatory standards.

Unencapsulated uses of coal ash are those where coal ash is used in a loose particulate, sludge, or other unbound form. Examples of unencapsulated uses include, but are not limited to:

Structural fill.
Agricultural use of flue gas desulfurization (FGD) gypsum.
Soil modification.
Loose aggregate.

When an unencapsulated use of CCR involves placement on the land of 12,400 tons or more in non-roadway applications, the user must demonstrate and keep records, and provide such documentation upon request, that environmental releases to groundwater, surface water, soil, and air are comparable to or lower than those from analogous products made without CCR, or that environmental releases to groundwater, surface water, soil and air will be at or below relevant regulatory and health-based benchmarks for human and ecological receptors during use.

Does EPA have a methodology for evaluating encapsulated or unencapsulated beneficial uses of CCR?

Initially, EPA developed its 2013 Methodology for Evaluating Encapsulated Beneficial Uses of Coal Combustion Residuals (2013 Methodology) and applied it to evaluate the use of fly ash in concrete and FGD gypsum in wallboard. EPA then proceeded to also develop a framework for evaluating the potential risks associated with unencapsulated uses of industrial non-hazardous secondary materials (secondary materials). In developing the framework to evaluate unencapsulated uses of secondary materials, EPA determined that the principles outlined in the 2013 Methodology are also applicable and relevant to unencapsulated uses. So, EPA combined the discussion of encapsulated and unencapsulated uses into a single document and renamed it the Methodology for Evaluating the Beneficial Use of Industrial Non-Hazardous Secondary Materials (BU Methodology) to reflect the broader scope.

EPA's newer BU Methodology may be used to evaluate the potential for impacts to human health and the environment for both encapsulated and unencapsulated uses of secondary materials, including unencapsulated CCR uses. EPA made the BU Methodology available to assist others with the design and review of beneficial use evaluations.

How does EPA’s newer Methodology for Evaluating the Beneficial Use of Industrial Non-Hazardous Secondary Materials work?

The BU Methodology presents an approach for evaluating a wide range of industrial non-hazardous secondary materials and their associated beneficial uses. As such, it may be used to evaluate the potential for impacts to human health and the environment for both encapsulated and unencapsulated uses of CCR. It is divided into three phases:

Planning and scoping.
Impact analysis.
Final characterization.

Each beneficial use evaluation conducted using the BU Methodology will progress through these three phases, but there is flexibility in how each is applied. The three phases incorporate the five analytical steps initially formulated in the 2013 Methodology.

Does EPA require the use of certain test methods or other data sources when evaluating beneficial uses?

EPA does not require any specific data sources, only that the data used for the evaluation are of sufficient quality to support the final conclusions of the evaluation. EPA prepared the Beneficial Use Compendium: A Collection of Resources and Tools to Support Beneficial Use Evaluations (BU Compendium) as a resource that provides further discussion of the considerations that may arise when planning a beneficial use evaluation, as well as an overview of existing resources and tools, such as test methods or screening benchmarks. Recommendations in the BU Compendium are intended to be broad and flexible to allow integration within any existing evaluation programs. However, those that use the BU Compendium are free to consider and incorporate other technically sound data sources and analytical approaches.

What conclusions about the use of CCR can EPA's BU Methodology be used to support?

EPA developed this methodology to evaluate the potential impacts to human health and the environment that may result from beneficial uses of industrial non-hazardous secondary materials, including CCR. This methodology may be used to show whether releases of constituents of potential concern, such as heavy metals, from proposed beneficial uses are comparable to or lower than those from an analogous product made with virgin materials, or are at or below relevant regulatory and health-based benchmarks for human and ecological receptors.

Has EPA evaluated any beneficial uses of CCR?

EPA applied the steps of the 2013 Methodology to two encapsulated beneficial uses:

the use of fly ash as replacement for portland cement in concrete.
the use of FGD gypsum as replacement for mined gypsum in wallboard.

The Agency applied the newer BU Methodology to evaluate the use of FGD gypsum in agriculture, demonstrating how the BU Methodology can be used on an unencapsulated beneficial use.

EPA’s national-scale evaluations illustrate how the BU Methodology can be applied to evaluate the potential for environmental impacts from both encapsulated and unencapsulated beneficial uses. EPA does not intend these evaluations to substitute for determinations made by the relevant state, Tribal, or local agencies on whether a particular use is appropriate and allowed within their jurisdiction. So, individuals interested in this beneficial use should consult with the relevant agencies in their jurisdiction to determine whether their specific use is appropriate under local environmental conditions and compliant with statewide requirements.

Will EPA evaluate other beneficial uses of CCR? If not, who is responsible for conducting evaluations of other CCR beneficial uses? What is EPA's role in evaluating these beneficial uses?

EPA does not plan on evaluating other beneficial uses of CCR. However, the BU Methodology is available so that federal or state authorities, beneficial users, and other interested parties can use it to evaluate other beneficial uses of CCR. Use of this methodology is voluntary, not regulatory, and is not a replacement for existing regulatory requirements. Many states have beneficial use programs, and they should be consulted to determine whether a specific CCR beneficial use is allowed. Others that use the BU Methodology should consult with the appropriate state agencies to determine whether the application of the methodology is consistent with all applicable state requirements. EPA does not have a role in reviewing or approving evaluations conducted by others, but can assist with any questions about how to properly apply the methodology.

Evaluation of Two Encapsulated Beneficial Uses of CCR

What are the conclusions of EPA’s evaluation of the use of fly ash as replacement for portland cement in concrete and FGD gypsum as replacement for mined gypsum in wallboard?

EPA evaluated the use of fly ash as replacement for portland cement in concrete and FGD gypsum as replacement for mined gypsum in wallboard. The evaluation considered products that meet relevant physical and performance standards, that conform to standard design specifications, and that incorporate fly ash and FGD gypsum from pollution control devices currently used in the United States. Based on the findings of the evaluation, the Agency concluded that fly ash concrete and FGD gypsum wallboard are both appropriate beneficial uses. So, the Agency continues to support the beneficial use of fly ash in concrete and FGD gypsum in wallboard.

What types of literature sources did the Agency rely upon in its evaluation of the use of fly ash as replacement for portland cement in concrete and FGD gypsum as replacement for mined gypsum in wallboard?

This evaluation relied on a range of studies and data to characterize the composition and behavior of FGD gypsum generated within North America. In most cases, the information was drawn from peer reviewed journals and previous Agency data collection efforts in support of regulatory efforts. Much of these data sources were made available for comment to both the public and a panel of independent peer reviewers through the 2010 Human and Ecological Risk Assessment of Coal Combustion Wastes. An assessment determined whether data sources were relevant, sufficiently explained the data and assumptions relied upon, accounted for sources of uncertainty and variability, and had undergone an independent review in some form. Some data were submitted directly to EPA by generators, regulatory entities, and other interested parties. These characterization data were included as part of the full evaluation.

Evaluation of an Unencapsulated Beneficial Use of CCR

Can the use of FGD gypsum as a replacement for mined gypsum in agriculture provide benefits?

Yes, when FGD gypsum is applied at appropriate rates, it can provide a range of benefits to fields, such as providing key nutrients to crops and limiting phosphorus runoff to nearby water bodies. Using FGD gypsum, as opposed to using mined gypsum, may also provide benefits outside of agricultural fields, such as helping to reduce greenhouse gas emissions from mining, diverting this waste from CCR landfills, and providing cost savings to farmers.

What are the conclusions of EPA’s evaluation of the use of FGD gypsum as replacement for mined gypsum in agriculture?

EPA evaluated the use of FGD gypsum in agriculture to demonstrate how the BU Methodology can be applied to unencapsulated beneficial uses. The evaluation identified no concerns for most modeled application scenarios. EPA identified some limited potential for risk from the release of selenium to surface water when FGD gypsum is applied across every available field in a watershed at the highest rates and frequencies. Yet even in this extreme and unlikely scenario, modeled risks can be mitigated through minor limits on application practices. Based on the results of this evaluation, the use of FGD gypsum can provide benefits to agricultural fields while remaining protective of human health and the environment.

EPA’s evaluation focused on potential environmental impacts unique to FGD gypsum. However, risks can also result from the mismanagement of other types of gypsum. For example, studies found that the high concentrations of sulfate found in all types of gypsum may pose risk to cattle that are allowed to graze in fields too soon after application. The United States Department of Agriculture (USDA) developed guidelines to address the risks that are shared among all types of gypsum in Conservation Practice Standard: Amending Soil Properties with Gypsum Products. These guidelines identify relevant application rates intended to ensure the management of agricultural amendments remains protective of human health and the environment.

What types of data sources did the Agency rely upon in this evaluation of the use of FGD gypsum as replacement for mined gypsum in agriculture?

This evaluation relied on a range of studies and data to characterize the composition and behavior of FGD gypsum generated within North America. In most cases, the information was drawn from peer reviewed journals and previous Agency data collection efforts in support of regulatory efforts. Much of these data sources were made available for comment to both the public and a panel of independent peer reviewers through the 2010 Human and Ecological Risk Assessment of Coal Combustion Wastes. An assessment determined whether data sources were relevant, sufficiently explained the data and assumptions relied upon, accounted for sources of uncertainty and variability, and had undergone an independent review in some form. These characterization data are available in a separate database alongside the full evaluation.

Additionally, EPA reviewed available data generated by USDA and consulted with USDA staff to help define the types of applications for which gypsum has been shown to provide a functional benefit, the range of agronomically relevant application rates and frequencies to provide this benefit, where in the country gypsum might be applied, and potential magnitude of uptake into crops. The information relied on is all summarized within the evaluation.