DERR-2025-004868

Memorandum
TO: PacifiCorp
FROM: Troutman Pepper Locke
DATE: May 27, 2025
RE: Characterization and Management of Coal and Coal Combustion Residuals
(CCR) at Former Carbon Plant

In 2018, PacifiCorp entered into a Voluntary Cleanup Program (VCP) agreement with the Utah
Department of Environmental Quality, Division of Environmental Response and Remediation
(DERR) to remediate portions of the former Carbon Plant in Castle Gate, Utah. The Carbon
Plant was a coal-fired electric generating facility that operated between the 1950’s and 2015.
During the operating life of the facility, coal combustion residuals (CCR) were placed in on-site
landfills for disposal. Some unburned coal and CCR was also beneficially used in berms,
roadbeds, pipeline trenches as bedding material, and embankments. Recently, DERR
questioned whether coal and CCR that may be encountered within the VCP area should be
tested, managed and disposed of as hazardous waste, or otherwise influence cleanup decisions
under the VCP agreement. As explained below, the answer is no.
Under applicable federal law, unburned coal that is discarded or beneficially reused would not
be considered a listed hazardous waste under the Resource Conservation and Recovery Act
(RCRA); nor would it be expected to exhibit a hazardous waste characteristic. See generally,
40 CFR Part 261.
In addition, EPA has adopted rules to regulate CCR as a non-hazardous solid waste that is
subject to nationally applicable minimum criteria for safe disposal in landfills and surface
impoundments pursuant to subtitle D of RCRA. 80 Fed. Reg. 21302, 21303 (April 17, 2015). As
part of the rulemaking, EPA specifically declined to regulate CCR as special or hazardous waste
under subtitle C of RCRA. Id. The federal CCR rule applies directly in all states except where a
state has requested and received approval to implement a state CCR permit program in lieu of
the federal rule pursuant to the 2016 Water Infrastructure Improvements for the Nation (WIIN)
Act (codified at 42 U.S.C. § 6945(d)). To date, only Oklahoma, Texas and Georgia have
received final EPA approval for their state CCR permit programs. As a result, the federal CCR
rule continues to apply directly in Utah (as well as in most other states).
While the disposal of CCR in landfills and surface impoundments is regulated, the beneficial use
of CCR is not. In the 1980 Bevill Amendments to RCRA, Congress found that “solid waste
contains valuable … material resources which can be recovered and used, thereby conserving
increasingly scarce and expensive … virgin materials,” 42 U.S.C. § 6941a(2), and it required
EPA to conduct “a detailed and comprehensive study … of the disposal and utilization of
[CCR].” 42 U.S.C. § 6982(n). EPA subsequently issued Bevill Regulatory Determinations in
1993 and 2000 in which the agency concluded that the beneficial use of CCR does not warrant
federal regulation at all—as either a hazardous or a non-hazardous waste. See 50 Fed. Reg.
42466 (Aug. 9, 1993) and 65 Fed. Reg. 32214 (May 22, 2000). As part of the first national CCR
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rulemaking in 2015, EPA retained the exclusion for CCR that is beneficially used, and codified
this exclusion in 40 CFR § 257.50(g).
Since the former Carbon Plant on-site landfills ceased receiving CCR prior to October 19, 2015,
they are also excluded from regulation under the federal CCR rule. See 40 CFR § 257.50(d). In
addition, although EPA initially identified two former on-site wastewater treatment ponds (SPD-1
and SPD-2) as potential legacy CCR surface impoundments in proposed amendments to the
federal CCR rule in 2023, EPA corrected this error in response to PacifiCorp comments. See
Volume I: Response to Comments, Legacy CCR Surface Impoundments, at p. 257 (Docket ID
EPA-HQ-OLEM-2020-0107). As a result of this correction, neither the beneficial use areas nor
the closed landfills at the former Carbon Plant are subject to the federal CCR rule. This is
because the rule, as amended in 2024, only applies to active facilities (i.e., those generating
electricity on or after October 19, 2015), or inactive facilities with at least one legacy CCR
surface impoundment. See 89 Fed. Reg. 38,950, 39099 (May 8, 2024) (codified at 40 CFR §
257.50(c), (d) and (e)).
In summary, coal and CCR that was beneficially used on-site at the former Carbon Plant is not
subject to any RCRA regulatory requirement that would necessitate testing, management or
disposal as anything other than non-hazardous solid waste. Nor is it subject to special handling
under any of the “applicable statutes and rules” identified in the VCP agreement. To the
contrary, coal and CCR should be considered “inert waste” suitable for use as fill under Utah
Code R315-301-4 (provided that PacifiCorp does so in a manner that prevents hazards or
nuisance conditions).
This means that if coal or CCR is encountered and needs to be removed as part of the VCP
project, PacifiCorp should have the option to beneficially use the coal and CCR (e.g., as
structural fill, backfill and bedding material in a pipeline trench, or for roadbeds or
embankments) either on-site or off-site.1 PacifiCorp would also have the option to transport it to
a regulated CCR unit at another PacifiCorp facility or to an approved offsite landfill for disposal
as non-hazardous solid waste.

1 We note that between 2022 and 2024, EPA took questionable positions over whether and how the
beneficial use exclusion would apply on-site as opposed to off-site. However, those positions would not
change our analysis at the former Carbon Plant, since it is not subject to the federal CCR rule.