Court Opinion

ID: 9950731
Source: CourtListenerOpinion
Date Created: 2024-03-14 17:06:20.890628+00
Date Added: 2024-06-11T14:36:16.236253
License: Public Domain

2024 IL App (4th) 210304
                                                                           FILED
                    NOS. 4-21-0304, 4-21-0309, 4-21-0310 cons.           March 13, 2024
                                                                          Carla Bender
                          IN THE APPELLATE COURT                     4 th District Appellate
                                                                            Court, IL
                                  OF ILLINOIS

                               FOURTH DISTRICT

MIDWEST GENERATION, LLC,                         )
            Petitioner-Appellant,                )
            v.                                   )
THE ILLINOIS POLLUTION CONTROL BOARD,            )
                                                 )
            Respondent-Appellee.                 )
___________________________________________      )
                                                 )
DYNEGY MIDWEST GENERATION, LLC;                  )
ILLINOIS POWER GENERATING COMPANY;               )
ILLINOIS POWER RESOURCES GENERATING,             )
                                                 )   Petition for Direct Administrative
LLC; ELECTRIC ENERGY, INC.; and KINCAID
                                                 )   Review of the Order of the Illinois
GENERATION, LLC,                                 )   Pollution Control Board.
            Petitioners-Appellants,              )
            v.                                   )   PCB No. R20-19
THE ILLINOIS POLLUTION CONTROL BOARD,            )
            Respondent-Appellee.                 )
___________________________________________      )
                                                 )
                                                 )
AMERENENERGY MEDINA VALLEY COGEN,                )
LLC; and UNION ELECTRIC COMPANY, d/b/a           )
Ameren Missouri,                                 )
                                                 )
           Petitioners-Appellants,               )
           v.                                    )
                                                 )
THE ILLINOIS POLLUTION CONTROL BOARD,
                                                 )
           Respondent-Appellee.

           JUSTICE STEIGMANN delivered the judgment of the court, with opinion.
           Justices Harris and DeArmond concurred in the judgment and opinion.
                                              OPINION

¶1              In 2019, the Illinois General Assembly directed the Illinois Pollution Control Board

(Board) to adopt rules establishing requirements for the construction, design, operation, and

closure of coal ash surface impoundments. See Pub. Act 101-171 (eff. July 30, 2019) (adding 415

ILCS 5/22.59).

¶2              In April 2021, the Board issued its final order adopting part 845 of the Illinois

Administrative Code (35 Ill. Adm. Code 845), which, among other things, (1) defined coal

combustion residue (CCR) “surface impoundment” to include impoundments that no longer

contain water (also called “dry impoundments”) (see 35 Ill. Adm. Code 845.120 (2021)),

(2) required the owner or operator of a CCR surface impoundment to conduct monthly

groundwater elevation monitoring (id. § 845.650(b)), (3) required an owner or operator of a CCR

surface impoundment who elected to close an impoundment by removing all of the CCR to also

remove the impoundment liner (id. § 845.740(a)), and (4) required the owner or operator of a CCR

surface impoundment who elected to close an impoundment by leaving the CCR in place to install

a final cover system that is at least six feet thick (id. § 845.750(c)).

¶3              In May 2021, three separate petitions for administrative review were filed,

challenging portions of part 845 on the basis that the Board either exceeded its authority or acted

arbitrarily and capriciously. The petitions were filed by (1) Midwest Generation, LLC (Midwest);

(2) Dynegy Midwest Generation, LLC, Illinois Power Generating Company, Illinois Power

Resources Generating, LLC, Electric Energy, Inc., and Kincaid Generation, LLC (collectively,

Dynegy); and (3) AmerenEnergy Medina Valley Cogen, LLC, and Union Electric Company, d/b/a

Ameren Missouri (collectively, Ameren). On the Board’s motion, we have consolidated the three

petitions for review.

                                                  -2-
¶4             We disagree with petitioners that the Board acted arbitrarily and capriciously or

exceeded its authority and affirm the final order of the Board adopting part 845 as Illinois’s first

set of statewide standards regulating the storage and disposal of coal ash in surface impoundments.

¶5                                     I. BACKGROUND

¶6                             A. CCR and Surface Impoundments

¶7             When a power plant burns coal, it produces CCR, which contains contaminants like

mercury, cadmium, and arsenic. Depending on the type of coal used, CCR can also contain such

chemical constituents as barium, chromium, fluoride, lead, lithium, radium 226 and 228, and

thallium. Because these chemical constituents of CCR are soluble and mobile, they pose a risk

absent proper management of contamination to soil, surface water, and groundwater near power

plants.

¶8             CCR is a major form of industrial waste. In 2014, coal-burning facilities in the

United States generated about 130 million tons of CCR. CCR can take the form of either wet sludge

or dry powder. Dry CCR can be disposed of at a landfill. Wet CCR is generally sluiced by a pipe

to an on-site surface impoundment.

¶9             A CCR surface impoundment typically consists of (1) a primary cell, in which the

majority of the solid particles settle out of the wastewater and (2) one or two secondary cells, in

which the very fine suspended solids settle out of the wastewater (also called a “polishing pond”).

Some CCR surface impoundments have a constructed liner, which allows the operator to utilize

heavy equipment to remove ash from the surface impoundment and dispose of it off-site.

¶ 10                         B. Federal and State Regulation of CCR

¶ 11           In 2008, a dike ruptured at a power plant in Tennessee, releasing 1.1 billion gallons

of CCR into a nearby river. The incident prompted the United States Environmental Protection

                                               -3-
Agency (USEPA) to develop rules, under the Resource Conservation and Recovery Act (42 U.S.C.

§ 6901 et seq. (2006)), regulating the storage and disposal of CCR. Simultaneously, the Illinois

Environmental Protection Agency (IEPA) developed a coal ash impoundment strategy that

required groundwater monitoring at all power plants in Illinois that use coal as a fuel source.

Additionally, in 2011, the Board issued site-specific rules for the closure of Ameren’s CCR

impoundments at its Hutsonville power plant. See 35 Ill. Adm. Code § 840. After Ameren sought

a site-specific rule for the closure of another 16 of its ash ponds at 8 other facilities, the IEPA

proposed a rule of general applicability for all coal ash ponds at all power plants in Illinois.

¶ 12           In 2015, before Illinois’s rules were completed, the USEPA issued its final rules

regulating the storage and disposal of coal ash. These federal rules—codified in title 40, part 257,

of the Code of Federal Regulations (40 C.F.R. § 257.51 (2015))—became effective on October 19,

2015. (We note that we will use terms “federal rule” and “part 257” interchangeably.) The federal

rule defined “ ‘CCR surface impoundment ***’ [as] a natural topographic depression, man-made

excavation, or diked area, which is designed to hold an accumulation of CCR and liquids, and the

unit treats, stores, or disposes of CCR.” Id. § 257.53.

¶ 13           In 2016, Congress enacted the federal Water Infrastructure Improvements for the

Nation Act (WIIN Act), codified in relevant part at section 6945. 42 U.S.C. § 6945(d). The WIIN

Act provided for state regulation of CCR “units” in lieu of federal regulation if the state rules are

“at least as protective” as the rules in federal part 257. Id. § 6945(d)(1)(B). (In this opinion, we,

too, will use the term “unit” to mean a CCR surface impoundment.)

¶ 14           In 2019, the Illinois General Assembly passed Public Act 101-171, commonly

called the Coal Ash Pollution Prevention Act, which consisted entirely of amendments to the

Environmental Protection Act (Act). See Pub. Act 101-171 (amending 415 ILCS 5/1 et seq.).

                                                 -4-
Through this legislation, the General Assembly added section 22.59 of the Act, which directed the

IEPA to promulgate, and the Board to adopt, comprehensive rules governing the construction,

operation, and closure of CCR surface impoundments. See 415 ILCS 5/22.59 (West 2020). The

legislature directed that “[t]he rules must, at a minimum *** be at least as protective and

comprehensive as the federal regulations *** promulgated by the [USEPA] in [federal part 257]

governing CCR surface impoundments.” Id. § 22.59(g)(1).

¶ 15                         C. Rulemaking Under the Amendments

¶ 16                1. The IEPA’s Proposed Rules and the First-Notice Order

¶ 17           In March 2020, the IEPA filed with the Board its proposed new, statewide

regulations for CCR surface impoundments, which, if adopted, would be codified at title 35, part

845, of the Illinois Administrative Code. (We will refer to the Illinois regulations as “the State

regulations” or “part 845” interchangeably.) The proposed regulations were presented as a 135-

page attachment to the IEPA’s “Statement of Reasons,” a 45-page document, which (1) explained

the federal and state regulatory background of CCR and the purpose and effect of the proposed

regulations and (2) contained a section-by-section summary of the proposed regulations.

¶ 18           In April 2020, the Board entered an “Opinion and Order” (the “first-notice order”)

(1) accepting the IEPA’s proposal for rulemaking, (2) directing the clerk of the Board to publish

first notice of the proposed rules in the Illinois Register, in accordance with the requirements of

the Illinois Administrative Procedure Act (see 5 ILCS 100/5-40(b) (West 2020)), and (3) directing

“the assigned hearing officer to proceed to hearing under the rulemaking provisions of the Act.”

The Board attached the IEPA’s proposed rules as an addendum to the April 2020 order.

¶ 19           Relevant to this appeal, the IEPA proposal contained provisions (1) defining

“inactive CCR surface impoundment” to mean “a CCR surface impoundment in which CCR was

                                               -5-
placed before but not after October 19, 2015, and still contains CCR on or after October 19, 2015.

Inactive CCR surface impoundments may be located at an active facility or inactive facility,”

(2) requiring monthly groundwater elevation monitoring, (3) providing that closure of a CCR

surface impoundment by removal of the CCR was complete “when the CCR in the surface

impoundment and any areas affected by releases from the CCR surface impoundment have been

removed,” and (4) providing that closure of a CCR surface impoundment by leaving the CCR in

place required installment of a “final cover system” at least six feet thick.

¶ 20             The Board did not comment on the IEPA’s proposed rules at this time.

¶ 21                   2. The Board’s Request for an Economic Impact Study

¶ 22             Also in April 2020, the Board submitted a written request to the acting Director of

Commerce and Economic Opportunity, for the Department of Commerce and Economic

Opportunity (DCEO), that the DCEO conduct an economic impact study of the proposed rule

before June 2020. (We note that the DCEO did not perform the requested study.) That same month,

the executive director of the Joint Committee on Administrative Rules (JCAR) submitted a written

request to the chair of the Board that the Board provide to JCAR “an analysis of the economic and

budgetary effects of the [proposed Part 845]” for use as part of JCAR’s “review of this issue.”

¶ 23             The publication of proposed rules marked the beginning of the first-notice period,

during which interested parties—including industry groups, environmental groups, municipalities,

and individuals—submitted questions, responses to questions, and public comments and during

which public hearings were held. Midwest, Dynegy, and Ameren each participated in the first-

notice period.

¶ 24             Specifically, the Board held two sets of hearings lasting four days and two days,

respectively. Participants at the hearings included (1) the IEPA; (2) Environmental Law and Policy

                                                -6-
Center, Prairie Rivers Network, Sierra Club, and Little Village Environmental Justice

Organization (collectively, Environmental Groups); (3) Midwest, Dynegy, Ameren, and the City

of Springfield, the Office of Public Utilities; (4) Illinois Environmental Regulatory Group; and

(4) the office of the Illinois Attorney General.

¶ 25           The first set of hearings focused on the testimony of eight expert witnesses for the

IEPA. The second set of hearings focused on testimony from (1) six expert witnesses for the

Environmental Groups, (2) seven expert witnesses for Dynegy, (3) three expert witnesses for

Midwest, and (4) two expert witnesses for Ameren. At the hearings, 58 exhibits were introduced

and admitted. All of the witnesses testified under oath and were subject to cross-examination.

¶ 26           In addition to the hearings, the Board received both oral and written public

comments. The Board held four separate hearing sessions for oral public comments, at which 120

members of the public provided comments. The Board also received 138 written public comments.

We note that the record on appeal consists of over 29,000 pages of documents, transcripts, and

exhibits.

¶ 27                  3. The Second-Notice Order and Second-Notice Period

¶ 28           On February 4, 2021, the Board entered an order and opinion (the second-notice

order) submitting a revised version of the proposed rules for review by JCAR. In the 105-page

second-notice order, the Board (1) discussed contested issues and (2) made findings regarding

those issues, including those provisions petitioners challenge in this appeal.

¶ 29           The entry of the second-notice order initiated the second-notice period under the

Illinois Administrative Procedure Act, during which Midwest, Dynegy, Ameren, the

Environmental Groups, the IEPA, and others addressed comments and arguments about the

proposed regulations to JCAR.

                                                   -7-
¶ 30                                4. The Board’s Final Order

¶ 31           On April 13, 2021, JCAR certified its lack of objection to the proposed rules, and,

on April 15, 2021, the Board issued its final order adopting the regulations as part 845 of the

Administrative Code (part 845) (35 Ill. Adm. Code 845). The Board stated that it would not repeat

the discussion of its rationales included in the second-notice order, thus effectively adopting the

statements in the second-notice order as the Board’s final statements on those points. The final

order was thus relatively brief.

¶ 32           Midwest, Dynegy, and Ameren each filed separate appeals challenging portions of

part 845. On the Board’s motion, we consolidated the three appeals.

¶ 33                                      II. ANALYSIS

¶ 34           Dynegy and Midwest share three arguments. They contend that the Board exceeded

its authority or acted arbitrarily and capriciously when it (1) defined “inactive CCR surface

impoundment” to include impoundments that no longer contain liquid (see 35 Ill. Adm. Code

845.120 (2021)), (2) required monthly groundwater elevation monitoring (id. § 845.650(b)(2)),

and (3) failed to properly address the technical feasibility and economic reasonableness of each of

the provisions Dynegy and Midwest challenge.

¶ 35           Midwest alone argues that the Board acted arbitrarily and capriciously by requiring

an operator who elects to close an impoundment by removing the CCR to also remove the

impoundment liner and ancillary structures. See id. § 845.740(a).

¶ 36           Dynegy alone argues that that the Board acted arbitrarily and capriciously by

requiring an operator who elects to close an impoundment by leaving the CCR in place to install a

final cover system that is thicker than those required by federal part 847. See id. § 845.750(c).

                                                -8-
¶ 37            Ameren argues separately that certain provisions of part 845 exceed the Board’s

authority because they have a retroactive effect, which the legislature did not explicitly authorize.

¶ 38            We disagree with petitioners that the Board acted arbitrarily and capriciously or

exceeded its authority and affirm the final order of the Board adopting part 845 as Illinois’s first

set of statewide standards regulating the storage and disposal of coal ash in surface impoundments.

¶ 39                                 A. The Standard of Review

¶ 40            The Illinois Constitution provides that it is the public policy of the State “to provide

and maintain a healthful environment for the benefit of this and future generations.” Ill. Const.

1970, art. XI, § 1. To enforce that policy, the General Assembly passed the Act (415 ILCS 5/1

et seq. (West 2020)), which established the Board as an independent body comprised of five

members with “verifiable technical, academic, or actual experience in the field of pollution control

or environmental law and regulation” (id. § 5(a)). “The Board is charged with determining and

defining environmental protection standards through rules and regulations.” County of Will v.

Pollution Control Board, 2019 IL 122798, ¶ 41, 135 N.E.3d 49 (citing 415 ILCS 5/5(b), 27(a)

(West 2016)).

¶ 41            When the Board promulgates regulations, it acts in a quasi-legislative capacity. Id.

¶ 42. “The Board’s regulations have the force and effect of laws, and they are presumptively valid.”

Id. The Board is “composed of technically qualified individuals [whose] expertise is essential in

crafting regulations.” Id. ¶ 43. Accordingly, judicial review of the Board’s decision to adopt certain

regulations is limited to determining whether the decision was arbitrary and capricious. Id. The

party challenging the Board’s decision to adopt a regulation bears the “heavy burden” of

demonstrating that the Board’s action was arbitrary and capricious. Id.; see Granite City Division

of National Steel Co. v. Illinois Pollution Control Board, 155 Ill. 2d 149, 162, 613 N.E.2d 719,

                                                 -9-
724-25 (1993) (“Regulations adopted by the Board pursuant to its statutory authority will not be

set aside unless they are arbitrary and capricious.”).

¶ 42           In Greer v. Illinois Housing Development Authority, 122 Ill. 2d 462, 505-06, 524

N.E.2d 561, 581 (1988), the supreme court provided the following guidance for determining

whether an agency’s action was arbitrary and capricious:

                       “While it is probably not possible to enumerate all the kinds of acts or

               omissions which will constitute arbitrary and capricious conduct, the following

               guidelines apply. Agency action is arbitrary and capricious if the agency: (1) relies

               on factors which the legislature did not intend for the agency to consider;

               (2) entirely fails to consider an important aspect of the problem; or (3) offers an

               explanation for its decision which runs counter to the evidence before the agency,

               or which is so implausible that it could not be ascribed to a difference in view or

               the product of agency expertise.”

¶ 43           In County of Will, 2019 IL 122798, ¶¶ 44-45, the supreme court observed that,

although the appellate court had applied Greer when reviewing decisions by the Board, the

supreme court had not yet done so. Nonetheless, because the parties had framed their arguments

using exclusively Greer’s three-factor rubric, the court also utilized the Greer framework for its

analysis because “the parties’ arguments would be otherwise difficult to cabin analytically.” Id.

Similarly, because the petitioners in the present case have framed their arguments utilizing the

Greer factors, our discussion of their arguments will likewise utilize primarily the Greer

framework. However, we reiterate that the Greer factors are not the exclusive ways in which an

agency’s decision may be found to be arbitrary and capricious.

                                                - 10 -
¶ 44           For example, the Greer court also wrote that “[t]he standard is one of rationality,”

observing that “sudden and unexplained changes have often been considered to be arbitrary.”

(Emphasis added.) Greer, 122 Ill. 2d at 506.

¶ 45           Additionally relevant to this appeal, a Board’s decision adopting a rule may be

arbitrary and capricious if the Board failed to comply with the requirements of section 27 of the

Act. See Waste Management of Illinois, Inc. v. Pollution Control Board, 231 Ill. App. 3d 278, 285-

89, 595 N.E.2d 1171, 1175-78 (1992). Section 27(a) of the Act requires that the Board, when

promulgating a regulation under the Act, “shall take into account *** the technical feasibility and

economic reasonableness of measuring or reducing the particular type of pollution.” 415 ILCS

5/27(a) (West 2020). Section 27(b) of the Act requires that the Board, when adopting any new

rule, “shall, in its written opinion, make a determination, based upon the evidence in the public

hearing record *** as to whether the proposed rule has any adverse economic impact on the people

of the State of Illinois.” Id. § 27(b). A regulation that fails to comply with section 27 may be

declared invalid by a reviewing court. Waste Management, 231 Ill. App. 3d at 289.

¶ 46           Petitioners also challenge portions of the rule on the basis that the Board exceeded

the authority granted to it by the legislature in section 22.59(g) of the Act. It is well established

that (1) “[an] agency is limited to those powers granted to it by the legislature in its enabling

statute” and (2) “[a]n act that is unauthorized is beyond the scope of the agency’s jurisdiction.”

Julie Q. v. Department of Children & Family Services, 2013 IL 113783, ¶ 24, 995 N.E.2d 977.

“When the agency renders a decision that [the agency] is without statutory authority to make, it is

without jurisdiction and the decision is void.” Id. Accordingly, “[t]he scope of powers conferred

on an administrative agency by its enabling legislation is a question of statutory interpretation

which we review de novo.” Id. ¶ 20.

                                               - 11 -
¶ 47               B. The Definition of “Inactive CCR Surface Impoundments”

¶ 48           Both Midwest and Dynegy argue that the definition of an “inactive CCR surface

impoundment” exceeds the Board’s authority under the amendments because its applications make

part 845 rules apply to sites that are not “CCR surface impoundments” under the Act.

Alternatively, they argue that the definition is arbitrary and capricious under the Greer factors.

¶ 49                                 1. Additional Background

¶ 50           When the legislature amended the Act to add section 22.59, which directed the

Board to promulgate CCR rules, the legislature also added section 3.143 to the Act, which defined

“CCR surface impoundment” to mean “a natural topographic depression, man-made excavation,

or diked area, which is designed to hold an accumulation of CCR and liquids, and the unit treats,

stores, or disposes of CCR.” 415 ILCS 5/3.143 (West 2020). The legislature copied this definition

from the federal part 257 definition of “CCR surface impoundment.” See 40 C.F.R. § 257.53

(2015). The Board, in turn, adopted the same definition. See 35 Ill. Adm. Code 845.120 (2021).

That is to say, the federal regulation, the Act, and the state regulation all share the same definition

of “CCR surface impoundment.”

¶ 51           The state and federal regulations diverge, however, when it comes to the definition

of “inactive CCR surface impoundment.” And the Act does not define that term at all. The federal

regulation defined “inactive CCR surface impoundment” to include only those impoundments

containing liquids. See 40 C.F.R. § 257.53 (2015) (“Inactive CCR surface impoundment ***.”).

¶ 52           As noted above, the federal regulation defining “CCR surface impoundment” and

“inactive CCR surface impoundment” went into effect on October 19, 2015. Id. § 257.51. Industry

and environmental groups challenged portions of the federal regulation in federal court. In Utility

Solid Waste Activities Group v. Environmental Protection Agency, 901 F.3d 414, 432-44 (D.C.

                                                - 12 -
Cir. 2018) (USWAG), the circuit court for the District of Columbia determined that the USEPA

acted arbitrarily and capriciously when it failed to regulate “inactive impoundments at inactive

facilities” (commonly known as “legacy ponds”—liquid-containing CCR surface impoundments

at closed power plants). The court explained that legacy ponds “are a particular subset of inactive

impoundments” distinguished from active surface impoundments only by their location at closed

plants. Id. at 432. The court reasoned that legacy ponds posed the same risks as active surface

impoundments and the USEPA’s approach, which was to wait until an imminent leakage was

detected or attempt clean-up after a spill occurred, amounted to “shrug[ging] off preventative

regulation” and “ma[de] no sense.” Id. at 433. Accordingly, the USEPA

       “acknowledge[d] that (i) it ha[d] the authority to regulate inactive units, (ii) it [was]

       regulating inactive units at active facilities, (iii) the risks posed by legacy ponds [were] at

       least as severe as the other inactive-impoundment dangers that [part 257 sought] to address,

       and [(iv)] there [was] no logical basis for distinguishing between units that present[ed] the

       same risks.” (Internal quotation marks omitted.) Id. at 434.

Thus, the court concluded that the legacy pond exemption was arbitrary and capricious and

remanded that provision to the USEPA.

¶ 53           At the time of the Board’s final order adopting part 845, the USEPA had not

produced an updated rule. In August 2020, the USEPA stated that it would address the court’s

vacatur of the legacy unit provision in later rulemaking (see Hazardous and Solid Waste

Management System: Disposal of Coal Combustion Residuals from Electric Utilities; A Holistic

Approach to Closure Part A: Deadline to Initiate Closure, 85 Fed. Reg. 53,516-18 (Aug. 28, 2020)

(to be codified at 40 C.F.R. pt. 257)), which occurred in May 2023, when the USEPA proposed to

amend part 257 to specify that legacy impoundments are subject to the same part 257 regulations

                                               - 13 -
applicable to CCR surface impoundments at active facilities. See Hazardous and Solid Waste

Management System: Disposal of Coal Combustion Residuals from Electric Utilities; Legacy

CCR Surface Impoundments, 88 Fed. Reg. 31,982-89 (proposed May 18, 2023) (to be codified at

40 C.F.R. pt. 257).

¶ 54                       2. Whether the Board Exceeded Its Authority

¶ 55           Midwest and Dynegy contend that section 22.59(g) of the Act, which requires the

Board to regulate “CCR surface impoundments,” leaves the Board without authority to adopt a

definition of “inactive CCR surface impoundment” that includes liquid-free impoundments.

Specifically, Midwest and Dynegy assert that by defining “CCR surface impoundment” to mean a

unit that “is designed to hold an accumulation of CCR and liquids” (emphasis in original) the

legislature evidenced an intent that the Board regulate only those units currently holding CCR and

liquids—not former units holding only dry CCR.

¶ 56           Midwest and Dynegy additionally argue that by adopting the federal definition of

“CCR surface impoundment,” the legislature expressed its intent that the Board regulate the “same

universe” of CCR surface impoundments as the federal rule. According to petitioners, when the

Board defined inactive units to include dry units, it expanded the universe of regulated units

beyond those regulated under the federal rule and, accordingly, exceeded the authority granted by

the legislature. We disagree.

¶ 57           “[B]ecause administrative regulations have the force and effect of law, the familiar

rules that govern construction of statutes also apply to the construction of administrative

regulations.” Haage v. Zavala, 2021 IL 125918, ¶ 43, 183 N.E.3d 830. “The surest and most

reliable indicator of intent is the language of the regulation itself.” People ex rel. Madigan v.

                                              - 14 -
Illinois Commerce Comm’n, 231 Ill. 2d 370, 380, 899 N.E.2d 227, 232 (2008). So, when the

language of a regulation is unambiguous, one must construe it as written. Id.

¶ 58           Section 3.143 of the Act defines “CCR surface impoundment” as “a natural

topographic depression, man-made excavation, or diked area, which is designed to hold an

accumulation of CCR and liquids, and the unit treats, stores, or disposes of CCR.” 415 ILCS

5/3.143 (West 2020). The Board defined an inactive CCR surface impoundment to be one “in

which CCR was placed before but not after October 19, 2015 [(the effective date of the federal

regulation)] and still contains CCR on or after October 19, 2015.” 35 Ill. Adm. Code 845.120

(2021).

¶ 59           Under the Board’s definition, an “inactive CCR surface impoundment” is merely a

type of “CCR surface impoundment.” As the Board explained in its second-notice order, “for an

impoundment to be an inactive surface impoundment, first it must be a CCR surface impoundment,

which is defined in Section 845.120 [(35 Ill. Adm. Code 845.120 (2021))] as being designed to

‘hold CCR and liquid.’ ”

¶ 60           Put another way, a CCR surface impoundment need only be designed to hold CCR

and liquid, not currently holding CCR and liquid. Accordingly, a dry surface impoundment that

was designed to hold liquid but no longer holds liquid first qualifies as a “CCR surface

impoundment” by virtue of its design and next qualifies as an “inactive CCR surface

impoundment” by virtue of its current state being liquid-free.

¶ 61           Further, if the plain meaning of “is designed to hold an accumulation of CCR and

liquids” (40 C.F.R. § 257.53 (2015)) necessarily implies any “CCR surface impoundment” must

currently hold liquid, the USEPA’s definition of an inactive impoundment would contain

surplusage. The federal definition states, an “inactive CCR surface impoundment” “means a CCR

                                              - 15 -
surface impoundment that no longer receives CCR on or after October 14, 2015 and still contains

both CCR and liquids on or after October 14, 2015.” (Emphasis added.) Id. Specifying the unit

“still contains *** liquids” would be redundant if containing liquid were inherent in the definition

of a CCR surface impoundment.

¶ 62           Additionally, the plain language of the Act establishes that the legislature did not

restrict the Board to regulating the “same universe” of surface impoundments as the federal

regulations. Midwest and Dynegy ask this court to infer the legislature’s intent from its adoption

of the federal definition of “CCR surface impoundment.” But we need not infer anything. The

legislature clearly expressed its intent through the plain language it utilized in the Act. In section

22.59, the legislature expressly stated that (1) it is the long-standing policy of the State to protect

the air, land, and waters of Illinois, (2) CCR has caused groundwater contamination “at active and

inactive plants throughout this state,” and (3) “environmental laws should be supplemented to

ensure consistent, responsible regulation of all existing CCR surface impoundments.” (Emphasis

added.) 415 ILCS 5/22.59(a) (West 2020).

¶ 63           Importantly, the legislature also directed that (1) “[t]he provisions of [section

22.59] shall be liberally construed to carry out the purposes of this Section” (emphasis added) (id.)

and (2) the Board shall adopt rules regulating, among other things, closure and post-closure care

of CCR surface impoundments that “must, at a minimum *** be at least as protective and

comprehensive as the federal regulations *** in [part 257] governing CCR surface impoundments”

(emphasis added) (id. § 22.59(g)).

¶ 64           The plain language of the Act demonstrates that the legislature directed the Board

to promulgate rules that would protect Illinois groundwater from CCR contamination at existing

CCR surface impoundments at active or inactive plants. The legislature’s command that the Board

                                                - 16 -
promulgate rules that are at least as protective as the federal rules demonstrates that the legislature

granted the Board authority to promulgate rules that were more protective than the federal ones.

¶ 65           We additionally note that the legislature chose not to adopt the federal definition of

“inactive CCR surface impoundments,” leaving to the Board the task of defining that term. If the

legislature had intended for the state definition of “inactive CCR surface impoundment” to be the

same as the federal definition, it would have adopted the federal definition, as it did for “CCR

surface impoundment.”

¶ 66           Accordingly, we conclude that the Board did not exceed its authority by defining

“inactive CCR surface impoundment” to include CCR surface impoundments that are designed to

hold liquid but do not currently hold liquid.

¶ 67                   3. Whether the Definition Is Arbitrary and Capricious

¶ 68           Midwest and Dynegy both contend that the Board’s definition of “inactive CCR

surface impoundment” is arbitrary and capricious. They frame their argument under the rubric of

the Greer factors, asserting that the Board (1) considered a factor the legislature did not intend

when the Board considered “whether a unit was once a CCR surface impoundment rather than

whether it is a CCR surface impoundment on the date the [Act] was enacted (emphases in

original),” (2) failed to consider an important aspect of the problem because it did not evaluate the

potential for groundwater contamination from dry units, and (3) offered an explanation for its

decision that runs counter to the evidence. We disagree.

¶ 69           We have already concluded that the Board did not exceed its authority by including

dry impoundments within the definition of inactive impoundments and, accordingly, have

addressed Midwest and Dynegy’s first argument. We now address Midwest and Dynegy’s second

and third arguments.

                                                - 17 -
¶ 70                          a. The Board’s Findings and Rationale

¶ 71           Because an agency’s action must be upheld, if at all, on the basis articulated by the

agency itself (Department of Central Management Services v. Illinois Labor Relations Board,

State Panel, 2018 IL App (4th) 160827, ¶ 37, 116 N.E.3d 388), an understanding of the Board’s

explanation for including dry units in the part 845 definition of “inactive CCR surface

impoundments” is necessary.

¶ 72           The Board’s rationale for adopting the definition is contained within the second

notice order. In that order, the Board noted that Dynegy objected to the IEPA’s proposed definition,

which included dry units, because it “ ‘expanded the scope of Part 845 beyond the [part 275] Rule,

and more importantly, beyond the statutory mandate, by regulating units not fitting the legislature’s

definition of “CCR surface impoundment.’ ” Moreover, Dynegy argued that the “ ‘IEPA definition

created confusion as to whether units that did not contain liquids as of the date of the [part 257]

Rule became effective may be regulated under Part 845.’ ”

¶ 73           The Board also noted that the IEPA opposed retaining the federal part 257

definition of inactive surface impoundment because, in the IEPA’s experience, “some unlined

surface impoundments have leaked to the point that the CCR became dry.” Moreover,

“ ‘experience has shown a cover system is needed to control potential effects to health and to the

environment to the maximum extent possible.’ ” The IEPA further opined that “an impoundment

should not avoid regulation under part 845 simply because the liquids in the impoundment have

already leaked into the environment or have been removed in preparation for closure.”

¶ 74           The Board accepted the IEPA’s proposed definition, stating as follows:

                       “At issue is whether the inactive surface impoundment was ‘designed to

               hold CCR and liquids, but still contains CCR,’ or ‘designed to hold CCR but

                                               - 18 -
              contains both CCR and liquids’ on or after the proposed cutoff date of October 19,

              2015. The Board agrees with the former intent, which is reflected in the IEPA’s

              proposed definition.

                      ***

                      The Board notes that for an impoundment to be an inactive surface

              impoundment, first it must be a CCR surface impoundment, which is defined in

              Section 845.120 as being designed to ‘hold CCR and liquid.’ The next condition is

              that CCR should have been placed in the impoundment before but not after October

              19, 2015[,] and still contains CCR on or after October 19, 2015. [Citation.] Thus,

              the Board finds that the proposed definition of Inactive [sic] CCR surface

              impoundment does not expand of the regulations as argued by Dynegy. Further, the

              Board finds that the definition is consistent with the federal regulations and

              provides clarity on the unintended consequences of excluding CCR surface

              impoundments containing CCR that may have leaked or were drained before the

              cutoff date.”

¶ 75           b. The Potential for Groundwater Contamination From Dry Units

¶ 76          Having set forth the Board’s rationale for adopting the IEPA’s proposed definition,

which included dry impoundments, instead of incorporating the federal part 257 definition, which

included only liquid impoundments, we turn now to Dynegy’s and Midwest’s argument that the

Board, when adopting the more expansive definition, failed to consider an important part of the

problem—namely, the absence of potential groundwater contamination from inactive dry

impoundments. Put another way, Dynegy and Midwest contend that no evidence was presented

during rulemaking that dry impoundments pose a risk to groundwater.

                                             - 19 -
¶ 77             Although Midwest and Dynegy have attempted to frame their argument as fitting

neatly within the second Greer factor, we need not engage in such complicated contortions; their

argument is simply that the Board’s inclusion of dry impoundments in part 845 regulation was not

supported by evidence that dry impoundments pose a risk to groundwater.

¶ 78             We disagree. The Board explained the reasoning for its decision in the second

notice order. Specifically, the Board noted that the IEPA opposed conforming the definition of

inactive CCR surface impoundments with the federal definition because some unlined CCR

surface impoundments have leaked to the point they have become dry. The IEPA opined that “an

impoundment should not avoid regulation under part 845 simply because the liquids in the

impoundment have already leaked into the environment or have been removed in preparation for

closure.”

¶ 79             The Board points in its brief to evidence presented during rulemaking that when

dry coal ash becomes wet due to rainfall or flooding, it can leach into groundwater if the

impoundment is not properly lined or covered. One example of such evidence is the written joint

testimony of expert witnesses Scott Payne and Ian Magruder, who stated that high water tables can

cause CCR surface impoundments to become inundated with groundwater. They explained, “The

regular inundation of CCR in unlined or poorly lined impoundments creates a perpetual source of

contamination to groundwater because the high groundwater will rewet the CCR even after the

CCR impoundment is capped and closed.” Similarly, expert witness Mark Hutson, when

explaining in his written testimony why CCR must be permanently segregated from water, wrote

the following:

                 “During high water events, groundwater flows from the river into surrounding

                 sediments and groundwater beneath and within the impoundment will rise in

                                              - 20 -
               response, resulting in groundwater re-wetting any disposed ash remaining in the

               impoundment. The result of this re-wetting of ash will be enhanced production of

               leachate. Even minor but more frequent flood events stimulate formation and

               release of CCR constituents to groundwater from any CCR that is occasionally

               saturated by high groundwater.” (Emphases added.)

¶ 80           Because (1) the Board explained its reason for regulating dry impoundments and

(2) the record contains evidence that dry CCR can pose a risk to groundwater, Midwest and

Dynegy have not shown that the Board failed to consider an important aspect of the problem or

that the Board’s decision was unsupported by evidence when the Board adopted the IEPA’s

proposed definition of inactive CCR surface impoundment that included dry impoundments.

¶ 81           Dynegy contends that “extensive evidence was introduced *** that units no longer

containing water do not present risks to groundwater warranting regulation under Part 845.”

Dynegy first points to a USEPA risk assessment finding that liquid-containing units were those

most in need of regulation because of the hydraulic head imposed by impounded water. Because

of this, the USEPA limited its regulation to liquid-containing units. However, as we have

explained, the legislature gave the Board its blessing to promulgate rules that were more protective

than the federal ones. Accordingly, the USEPA’s decision to regulate only the greatest risk does

not mean that the Board acted improperly when it decided to regulate lesser risks. The Board was

specifically empowered to do so by the legislature.

¶ 82           Dynegy also points to evidence that treating its “Joppa West Ash Pond,” a dry

impoundment which has not received new CCR since the 1970s, as an inactive impoundment

would cause disruption to the environment because the closure process would require it to disturb

100 acres of thick vegetation, including large trees.

                                               - 21 -
¶ 83           However, as the Board has noted, it may apply adjusted standards when conditions

at a site warrant them. Under the Act, “[a]fter adopting a regulation of general applicability, the

Board may grant, in a subsequent adjudicatory determination, an adjusted standard for persons

who can justify such an adjustment consistent with subsection (a) of Section 27 of this Act.” 415

ILCS 5/28.1(a) (West 2020). When, as here, “a regulation of general applicability does not specify

a level of justification required of a petitioner to qualify for an adjusted standard” (id. § 28.1(c)),

the Board may grant individually adjusted standards, if among other things, “factors relating to

that petitioner are substantially and significantly different from the factors relied upon by the Board

in adopting the general regulation applicable to that petitioner” (id. § 28.1(c)(1)). Surely the Board

is aware of its ability under its own regulations to adjust individual standards when appropriate.

¶ 84           For these reasons, Midwest and Dynegy have failed to show that the Board failed

to consider an important aspect of the problem.

¶ 85           c. Whether the Board’s Justifications Run Counter to the Evidence

¶ 86           Midwest and Dynegy assert the Board’s explanation for the definition is “contrary

to the evidence” (the first part of the third Greer factor) because the Board offered incorrect legal

rationales for the definition. They contend that the Board provided three justifications for its

inclusion of dry units: (1) the definition does not impermissibly expand the scope of part 845,

(2) the definition is consistent with federal part 257, and (3) the definition provides clarity on the

unintended consequences (of the federal rule’s exclusion of dry units) of excluding CCR surface

impoundments that may have leaked or were drained before the cutoff date.

¶ 87           As to the first point, we have already determined that the definition did not

impermissibly expand the scope of part 845 and need not repeat that discussion here.

                                                - 22 -
¶ 88            As to the second point, Midwest and Dynegy argue that a simple comparison of the

definitions “make[s] clear that [the part 845 definition and the federal definition] do not cover the

same units.” However, in the second-notice order, the Board made clear it was adopting the

expanded definition to avoid excluding “CCR surface impoundments that may have leaked or were

drained before the cutoff date.” Because the Board recognized its definition was broader than the

federal definition, we will presume that when the Board stated that its definition was “consistent

with” the federal one, it meant its definition did not conflict with the federal definition, not that it

was exactly the same as part 257.

¶ 89            Regarding the third point, Midwest and Dynegy contend that no evidence was

presented suggesting that the USEPA unintentionally excluded dry impoundments or of any

unintended consequences flowing therefrom. However, we see nothing in the second-notice order

suggesting the Board deemed that the USEPA had unintentionally excluded liquid-free units from

its definition. Instead, the Board spoke of the “unintended consequence of excluding CCR surface

impoundments containing CCR that may have leaked or were drained before the cutoff date.”

(Emphasis added.)

¶ 90            Moreover, the Board explained that it deemed the exclusion of dry impoundments

in federal part 257 to have detrimental effects. Although the Board did not specify those effects,

we can easily infer that the use of the federal definition resulted in disparate treatment of liquid

containing impoundments that were drained as part of an approved closure process versus those

that were drained under a less controlled process. In other words, the Board saw the use of the

federal definition as creating a loophole for units that were dry either because they leaked or

because their owners drained them in advance of the effective date of the federal definition. Given

this disparity, the Board’s use of the phrase “unintended consequences” is logical; the difference

                                                 - 23 -
in treatment created an incentive for CCR unit operators to drain units or allow them to go dry in

advance of the federal rule’s effective date.

¶ 91           On this point, Dynegy contends that this “unintended consequence” could never

occur. Specifically, Dynegy notes that part 845 defines an “existing CCR surface impoundment”

as one in which “CCR is placed both before and after October 19, 2015, or for which construction

started before October 19, 2015 and in which CCR is placed on or after October 19, 2015.” 35 Ill.

Adm. Code. 845.120 (2021). Accordingly, Dynegy contends, existing impoundments are subject

to the full set of part 845 regulations, and the dewatering of an impoundment after October 19,

2015, would not change this.

¶ 92           We agree with Dynegy that the Board’s broadening its definition could not reach

back into the past to remove the incentive to dewater an impoundment before October 19, 2015.

But the second notice opinion suggests that the Board’s concern was with the unintended

consequence of the IEPA’s definition, which used the October 19, 2015, cutoff date, despite the

IEPA’s rulemaking occurring before that date. In other words, the Board wanted its rule to reach

units dewatered in advance of part 257’s promulgation. Moreover, the Board also stated it intended

its definition to reach units dewatered through leakage. Such units would not necessarily be ones

that had received CCR after October 19, 2015.

¶ 93           For the above reasons, we conclude that Midwest and Dynegy have not

demonstrated that the Board’s inclusion of dry impoundments in the definition of inactive CCR

surface impoundments was arbitrary and capricious under any of the Greer factors.

¶ 94           C. The Requirement for Monthly Sampling of Groundwater Elevations

                                                - 24 -
¶ 95           Midwest and Dynegy both contend the Board’s decision to require operators to take

monthly measurements of groundwater elevations at sampling wells (id. § 845.650(b)(2)) was

arbitrary and capricious.

¶ 96                                      1. Background

¶ 97                                a. Technical Background

¶ 98           The dispute here relates to the collection of hydrological data for the creation of a

potentiometric map. Section 845.620 of part 845 (id. § 845.620) requires the operator of an

impoundment to design and implement a hydrogeologic site characterization, which must include

a “[m]ap of the potentiometric surface.” Id. § 845.620(b)(16)(E). Important here, the data for

potentiometric maps comes from measuring groundwater elevation—in other words, the level of

the water in appropriate wells. The general purpose of groundwater elevation monitoring is to

understand the direction and rate of groundwater flows. In section 845.650, the Board required

groundwater elevation monitoring in order to predict when coal ash may merge with groundwater

that flows to other bodies of water and drinking water sources. During rulemaking, the parties

disagreed on how often groundwater elevation monitoring needed to be conducted.

¶ 99                        b. The Groundwater Monitoring Proposals

¶ 100          In the second-notice order, the Board set forth the proposals it had received from

rulemaking participants regarding the monitoring of groundwater elevations. The IEPA originally

proposed requiring operators to measure groundwater elevations monthly. Midwest and Dynegy

both proposed quarterly monitoring, with Dynegy proposing the additional requirement of daily

monitoring in one upgradient well and one downgradient well. Dynegy asserted that the IEPA’s

only basis for proposing monthly monitoring was that some commenters had asked for daily

monitoring, which the IEPA believed was too burdensome. Dynegy explained that its proposed

                                               - 25 -
daily monitoring at only two wells was based upon the recommendation of the Environmental

Groups’ witnesses, Magruder and Payne.

¶ 101           The Board further noted that the IEPA opposed Dynegy’s proposal because “ ‘it is

impossible to produce an accurate potentiometric map from just two daily groundwater elevation

levels—every other groundwater elevation on the map would have to be extrapolated from those

two elevations.’ ” The IEPA believed, however, that a potentiometric map based upon monthly or

quarterly groundwater elevation data would “help[ ] produce a visual demonstration of the

direction and gradient of groundwater flow at a site for each sampling event during various times

of the year.”

¶ 102                                c. The Board’s Findings

¶ 103           The Board agreed with the IEPA “that accurate potentiometric surface maps cannot

be produced using only two daily groundwater elevation measurements.” The Board also noted

that it was standard practice for operators to measure groundwater elevation at all wells when

conducting sampling required by other regulations, which occurred either quarterly or

semiannually.

¶ 104           The Board concluded as follows:

                       “As noted by Midwest Generation, IEPA proposed the monthly frequency

                under Section 845.650(b)(2) in response to comments it received prior to filing its

                proposal with the Board. Exh. 2 At 129-130. Since the daily monitoring proposal

                is burdensome and does not result in an accurate potentiometric surface map, the

                Board finds that the monthly monitoring frequency is an appropriate compromise.

                Therefore, the Board at second notice adopts the monthly groundwater elevation

                                               - 26 -
              monitoring requirement at Section 845.650(b)(2) without revision.” (Emphases

              added.)

¶ 105         In its findings above, the Board cited pages 129-30 of exhibit No. 2, which

constituted the IEPA’s prefiled answers to questions it received following its prefiled testimony

from its eight witnesses. At pages 129-30, the IEPA answered the following questions:

                      “a. Explain why monthly monitoring of groundwater elevation is required

              by Section 845.650(b)(2)?

                     Response: Public comments received           by [IEPA] suggested daily

              groundwater elevation monitoring. [IEPA] believes that frequency would result in

              unmanageably large data sets for reporting, while monthly monitoring significantly

              reduces the data burden, but provides additional groundwater flow direction points

              between the quarterly analytical chemistry monitoring events.

                        b. How did [IEPA] determine this frequency was not overly burdensome

               or economically reasonable?

                      Response: Groundwater monitoring at Bureau of Water permitted sites such

              as mine refuse disposal areas and other waste water treatment impoundments utilize

              a quarterly frequency, as well as Bureau of Land cleanup programs, such as the Site

              Remediation program, use quarterly groundwater monitoring frequencies.

                        c. Is there a less burdensome method for accomplishing [the IEPA’s] intent

               behind this provision?

                        Response: When drafting Part 845 [IEPA] determined that a quarterly

                monitoring frequency would meet the requirements of Section 22.59 of the Act,

                while being similar to many other groundwater monitoring programs within

                                              - 27 -
                  [IEPA]. If the Board were to propose an alternative to quarterly chemical or

                  monthly elevation monitoring schedules [IEPA] would consider the alternatives.”

¶ 106                                      2. This Case

¶ 107           Midwest and Dynegy argue that the Board’s monthly monitoring requirement was

arbitrary and capricious because the requirement failed each prong of the Greer test. Although

Midwest and Dynegy shoehorn their arguments into the Greer rubric, their arguments boil down

to an assertion that the requirement for monthly, as opposed to quarterly, groundwater elevation

monitoring was simply a compromise between competing recommendations (1) from the

Environmental Groups for daily monitoring and (2) the industry groups for quarterly monitoring.

Put another way, Midwest and Dynegy contend that the monthly requirement was adopted

(1) without technical justification and (2) in contravention of expert evidence supporting quarterly

monitoring.

¶ 108           The Board responds that the requirement for monthly monitoring was not arbitrary

and capricious because the record showed that quarterly monitoring offered a less complete data

set for groundwater monitoring. We agree with the Board.

¶ 109           The Board, in its second-notice order, noted that (1) Dynegy itself proposed

quarterly monitoring, with additional daily monitoring at two wells and (2) Dynegy’s

recommendation for the additional daily monitoring was based on testimony from the

Environmental Groups’ experts, Magruder and Payne. Dynegy’s own proposal, then, implies that

quarterly testing alone is insufficient.

¶ 110           Turning to the remaining options—(1) daily monitoring, as proposed by the

Environmental Groups and (2) monthly monitoring, as proposed by the IEPA—the Board adopted

monthly monitoring and referenced the IEPA’s explanation for monthly monitoring, found at

                                               - 28 -
pages 129-30 of exhibit No. 2. The IEPA, in response to questions received regarding the IEPA’s

witness testimony, explained that daily monitoring would result in unmanageable data sets and

monthly monitoring would (1) reduce the data burden (2) while providing additional data for

mapping groundwater flow.

¶ 111          The Board’s decision to adopt monthly monitoring in lieu of daily or quarterly

monitoring was supported by the evidence adduced during rulemaking and explained in the

second-notice order. Accordingly, the Board did not act arbitrarily or capriciously by adopting the

requirement for monthly groundwater monitoring.

¶ 112          D. The Requirement for Removal of Liners and Ancillary Equipment During

                                       Closure by Removal

¶ 113          Part 845 allows owners and operators to elect to close a surface impoundment by

either (1) removing or (2) covering the CCR. Section 845.740(a) applies to operators who “elect

to close a CCR surface impoundment by removing all CCR and decontaminating all areas affected

by releases of CCR from the CCR surface impoundment.” 35 Ill. Adm. Code 845.740(a) (2021).

In order for closure under this section to be complete, the operator must remove, in addition to all

CCR and CCR residue, all “containment system components such as the impoundment liner and

contaminated subsoils, and CCR impoundment structures and ancillary equipment.” Id.

¶ 114          Midwest argues that the Board acted arbitrarily and capriciously by requiring

removal of the impoundment liner because the Board (1) disregarded expert testimony that

geomembrane liners are nonabsorptive and can be decontaminated, negating the requirement for

removal, (2) lacked technical justification to require removal of the liner and associated equipment,

(3) relied on factors the legislature did not intend it to consider—namely, the preamble to a

proposed amendment to the federal regulation, and (4) made sudden and unexplained revisions to

                                               - 29 -
the rule. For these reasons, Midwest contends, section 845.750(a)’s requirement that operators

electing closure by removal also remove the impoundment liner fails all three prongs of the Greer

test.

¶ 115          The Board responds that the requirement for functionless liners to be removed was

not arbitrary and capricious because it furthered the purposes of the amendment by (1) ensuring

compliance with the federal closure process and (2) requiring removal of functionless liners.

¶ 116                                     1. Background

¶ 117          Because the Board ultimately adopted an amended version of section 845.750(a),

additional background about the IEPA’s original proposed regulation and the Board’s adoption of

the amended proposed regulation is helpful to our analysis.

¶ 118           a. The Federal Rule and the IEPA’s Original Proposed State Rule

¶ 119          In the first-notice order, the IEPA originally proposed a version of section

845.750(a) that was similar to the federal rule governing closure by removal, which read as

follows:

               “Closure by removal of CCR. An owner or operator may elect to close a CCR unit

               by removing and decontaminating all areas affected by releases from the CCR unit.

               CCR removal and decontamination of the CCR unit are complete when constituent

               concentrations throughout the CCR unit and any areas affected by releases from the

               CCR unit have been removed and groundwater monitoring concentrations do not

               exceed the groundwater protection standard established pursuant to § 257.95(h) for

               constituents listed in appendix IV to this part.” 40 C.F.R. § 257.102(c) (2015).

¶ 120          The IEPA’s original proposed version of section 845.740(a), which was contained

in the addendum to the first-notice order, closely tracked the federal rule and read as follows:

                                               - 30 -
              “Closure of removal by CCR. An owner or operator may elect to close a CCR

              surface impoundment by removing and decontaminating all areas affected by

              releases from the CCR surface impoundment. CCR removal and decontamination

              of the CCR surface impoundment are complete when the CCR in the surface

              impoundment and any areas affected by releases from the CCR surface

              impoundment have been removed.”

¶ 121             b. The USEPA’s Proposed Amendments to the Federal Rule

¶ 122         In March 2020, however, the USEPA issued notice of proposed changes to the

federal rule. See Hazardous and Solid Waste Management System: Disposal of CCR; A Holistic

Approach to Closure Part B: Alternate Demonstration for Unlined Surface Impoundments;

Implementation of Closure, 85 Fed. Reg. 12,456 (proposed Mar. 3, 2020) (to be codified at 40

C.F.R. pt. 257). In what Midwest calls the “preamble” to the proposed amendments (that is to say,

the USEPA’s explanation of its proposed amendments preceding the proposed amendments

themselves), the USEPA wrote as follows:

                      “C. Closure of CCR Units by Removal of CCR.

                      Closure by removal of CCR is one of two options provided in the CCR

              regulations to close a CCR surface impoundment or landfill. The closure by

              removal approach consists of two performance standards. First, the owner or

              operator must remove all CCR from the unit and decontaminate all areas affected

              by releases from the CCR unit. Second, the regulations specify that closure is

              complete when all CCR in the unit and any areas affected by releases from the CCR

              unit have been removed and groundwater monitoring demonstrates that there are

              no exceedances of any groundwater protection standard. See § 257.102(c).

                                             - 31 -
               Importantly, the second performance standard requires groundwater corrective

               action of a unit to be completed before the owner or operator can assert that closure

               of the unit has been completed.” Id. at 12,468.

¶ 123          The USEPA then explained that state representatives had expressed concern that

the requirement to complete groundwater corrective action can take longer to complete than the

closure timeframes provided in the regulations. Id. at 12,469. As a result, the USEPA proposed an

“additional closure [by removal] option” for owners or operators who could not complete the

groundwater corrective action by the time all other closure by removal activities had been

completed. Id. Under the new option, an owner or operator could select a “post-closure care”

period that extended the time allotted for the corrective groundwater measures to be completed.

Id.

¶ 124          The USEPA emphasized that it “[was] not proposing any substantive revisions to

the current closure standard when closing by removal of CCR under § 257.102(c) and [was] not

reopening those requirements to comment.” (Emphasis added.) Id. Instead, the USEPA was

“proposing to present the current closure standard in a slightly revised format to accommodate the

proposed action.” (Emphasis added.) Id.

¶ 125          After explaining the revision, the USEPA then wrote as follows:

                      “Removal and decontamination activities. These activities include

               removing or decontaminating all CCR and CCR residues, containment system

               components, contaminated subsoils, contaminated groundwater, and CCR unit

               structures and ancillary equipment. To qualify for the new closure by CCR removal

               option, [US]EPA is proposing that owners and operators would need to complete

               all removal and decontamination activities, except for groundwater corrective

                                               - 32 -
              action, which would be completed under the post-closure care provisions at

              § 257.104. To demonstrate that all CCR has been removed from the unit, the owner

              or operator would need to remove the entire contents of the CCR unit, including all

              CCR and any CCR residues. This would include, for example, the removal of any

              fugitive dust (CCR) discovered outside the waste unit boundary. In addition, any

              containment system components such as a bottom liner, contaminated subsoils, and

              unit structures and equipment (e.g., concrete outlet structures and ancillary piping)

              would have to be removed prior to closure of the unit. Finally, any areas affected

              by releases from the CCR unit must have been removed (e.g., impacted soils

              beneath the bottom liner system). The intent of this requirement is for the owner or

              operator to complete all CCR removal activities during closure prior to transitioning

              to the post-closure care period which will largely be a groundwater cleanup

              activity.” Id. at 12,469-70.

¶ 126         The USEPA then provided the proposed revised section 257.102(c), which read as

follows:

                      “(c) Closure by removal of CCR. An owner or operator closing a CCR unit

              by removal of CCR must follow the procedures specified in either paragraph (c)(1)

              or (c)(2) of this section. Closure by removal activities include removing or

              decontaminating all CCR and CCR residues, containment system components such

              as the unit liner, contaminated subsoils, contaminated groundwater, and CCR unit

              structures and ancillary equipment.” Id. at 12,477.

Subsection (c)(1) described the procedure for completing all removal and decontamination

activities during the active life of the CCR unit. Subsection (c)(2) described the procedure for

                                              - 33 -
completing all removal and decontamination activities during the active life and post-closure care

period of the CCR unit.

¶ 127                     c. The IEPA’s Proposed Amended State Rule

¶ 128          As a result, several months later, in October 2020, the IEPA proposed an amended

version of section 845.740(a). The IEPA explained as follows:

               “The current version of [the federal regulation] treats closure by removal and all

               associated corrective action as a single process, with closure not being complete

               until all corrective action has been completed. [Citation.] The USEPA proposal

               divides closure by removal into a two-step process. The first step is the physical

               removal of all CCR, containment systems and related structures, while the second

               step is the completion of any necessary groundwater corrective action.”

¶ 129          The IEPA then opined that the proposed amendments to the federal rule were “more

protective and comprehensive than [the federal rule] as it currently exists.” The IEPA then pointed

out ways in which proposed section 845.740 already incorporated some of these more protective

features of the federal proposal but noted that section 845.740(a) as drafted contained only

“generalized language that removal and decontamination of areas affected by releases must be

completed for closure by removal.” As a result, the IEPA proposed revising section 845.740(a)

“using the specific language from [the federal proposed changes] describing how to complete

closure by removal and an additional statement that closure by removal must be completed before

groundwater corrective action.” Specifically, the IEPA proposed to amend section 845.740(a) as

follows:

               “Closure by removal of CCR. An owner or operator may elect to close a CCR

               surface impoundment by removing all CCR and removing and decontaminating all

                                              - 34 -
              areas affected by releases of CCR from the CCR surface impoundment. CCR

              removal and decontamination of the CCR surface impoundment are complete when

              all CCR and CCR residues, containment system components such as the

              impoundment liner and contaminated subsoils, and CCR impoundment structures

              and ancillary equipment have been removed. Closure by removal shall be

              completed before the completion of a groundwater correction action pursuant to

              Subpart F. the CR in the surface impoundment and any areas affected by releases

              from the CCR surface impoundment have been removed.”

¶ 130         d. The Board’s Adoption of the IEPA’s Proposed Amended State Rule

¶ 131         In February 2021, in the second-notice order, the Board adopted the IEPA’s

proposed amended version of section 845.740(a). The Board wrote the following when explaining

its adoption of the amended regulation:

              “IEPA proposes several changes to Section 845.740 to clarify the proposed intent.

              First, IEPA amends subsection (a) using language from Part 257 addressing closure

              by removal to describe how to complete closure by removal and an additional

              statement that closure by removal must be completed before any groundwater

              corrective action. *** This amendment, IEPA explains, is intended to ensure

              consistency of the proposed rules with Part 257, which treats closure by removal

              as a two-step process, i.e., the physical removal of all CCR, containment systems

              and related structures followed by the completion of any necessary groundwater

              corrective action.

                   ***

                                            - 35 -
                    Board Findings. The Board finds that the IEPA’s changes ensure that the

               proposed rules are consistent with Part 257 and adopts them at second notice.

               (Emphases added.)”

¶ 132          To date, the USEPA has not adopted the amendments it proposed to part 257,

described above.

¶ 133                                      2. This Case

¶ 134          We conclude that Midwest has failed to show that the Board’s adoption of the

amended section 845.740(a) was arbitrary and capricious.

¶ 135          The Board explained that its adoption of the IEPA’s proposed changes to section

845.740(a) ensured consistency with the federal closure regulations. As we have noted above, the

initial draft of section 845.740(a) closely tracked the language of the federal rule. When proposing

amendments to the federal rule, the USEPA explained that the federal rule contemplated “two

performance standards,” being (1) removal and decontamination followed by (2) groundwater

corrective action. Upon examining proposed amendments to the federal rule, the IEPA determined

that the language of section 845.740(a) as proposed contained only “generalized language” that

removal and decontamination must be completed before corrective action could begin but did not

specify what was required for removal and decontamination to be completed. That is to say, the

IEPA believed the state rule, as proposed, lacked specificity about when the first performance

standard was met and when the second standard could begin. For that reason, the IEPA proposed

adding language to the rule that would provide additional direction and ensure consistency with

the federal rule and its dual performance standards.

                                               - 36 -
¶ 136           The Board agreed and adopted the proposed language. We find no fault with the

Board’s explanation that it adopted the rule to ensure consistency with the federal rules, which was

explicitly what the legislature called upon the Board to do.

¶ 137           Midwest contends that section 845.740(a) is not consistent with the federal rule

because the liner removal requirement appears only in the preamble to the federal amendments

and not in the federal rule itself. We reiterate that the legislature mandated the Board to promulgate

rules that were at least as protective as the federal rules, not exactly the same as the federal rules.

That is to say, the legislature gave the Board authority to promulgate more protective rules, but

not less protective rules.

¶ 138           The IEPA believed, and the Board agreed, based upon the USEPA’s interpretation

of its own regulation, that greater clarity regarding what constituted completion of the removal

process would ensure consistency with the federal rules. That is to say, whether the USEPA

ultimately adopted the proposed amendments or not, clarifying the state regulation to provide

explicit standards regarding completion of the removal portion of the closure process would ensure

that the state regulation would never be less protective than the federal standard. In the context of

the legislature’s explicit mandate to the Board, section 845.740(a)’s liner removal requirement

does indeed ensure consistency with the federal rule.

¶ 139           Furthermore, the Board acted well within its authority to impose the liner

requirement. Importantly, the legislature explicitly directed the Board to “adopt rules establishing

*** closure and post-closure care requirements” that “must, at a minimum *** define when

complete removal of CCR is achieved and specify the standards for responsible removal of CCR

from CCR surface impoundments.” (Emphasis added.) 415 ILCS 5/22.59(g)(10) (West 2020).

                                                - 37 -
¶ 140           Midwest also contends that the liner removal requirement (1) ignored expert

evidence that a geomembrane liner could be decontaminated and left in place instead of removed

and (2) lacked technical justification. We disagree.

¶ 141           First, Midwest points in its brief to the testimony of a single expert—its own—who

testified that geomembrane liners can be decontaminated and opined that “allowing an effective

liner to remain in place was a better and more environmental alternative than requiring removal

and disposal of a perfectly good liner in a landfill.” Midwest concedes that this testimony was

given “regarding reuse of the liner to retrofit the liner compared to closure-by-removal,” but it

asserts that this is “a distinction without a difference.”

¶ 142           We again disagree. Retrofitting a liner for further use is an entirely different context

than leaving a useless liner in place after closing an impoundment. The Board was not obligated

to credit testimony that a liner can be decontaminated and left in place for further use when

promulgating standards for the closure by removal process, which contemplates no further use for

the synthetic liner.

¶ 143           Second, the Board points to evidence presented during rulemaking that supports the

liner removal requirement. Specifically, the Environmental Groups filed a final posthearing

response addressing contaminated soil beneath impoundment liners with citations to authority. The

filing establishes that soil underneath a liner can become contaminated with CCR, for example,

through leaching or damage. During rulemaking, on cross-examination by Midwest, the IEPA

explained that leaving the liner in place can prevent contaminated subsoil from being detected or

removed. As such, the liner removal requirement is necessary to ensure the complete removal of

CCR during the closure process.

                                                 - 38 -
¶ 144          Last, Midwest contends that the liner removal requirement was arbitrary and

capricious because it constituted a sudden and unexplained revision to the final rule. We disagree.

¶ 145          In August 2020, the IEPA filed its prefiled answers to questions resulting from its

prefiled testimony. In response to the question, “What does [IEPA] mean by ‘decontaminated’?”,

the IEPA answered, “In the instance of closure by removal, decontaminated means removal of all

ash, soil covers, liners, leachate within the impoundment, collection systems, and contaminated

soil.” Accordingly, we agree with the Board that Midwest was on notice as early as August 2020

that the IEPA believed liner removal was a necessary requirement for closure by removal.

¶ 146          For these reasons, we conclude that the Board’s adoption of the liner removal

requirement was not arbitrary and capricious.

¶ 147                     E. The Requirement for Final Cover Systems

¶ 148          When an operator chooses to close an impoundment by leaving the CCR in place,

both part 845 and part 257 require the operator to cover the dewatered impoundment with a final

cover system. See 35 Ill. Adm. Code 845.750 (2021); 40 C.F.R. § 257.102(d) (2015). Part 845,

however, requires thicker covers than its federal counterpart because the Board adopted the cover

standard applicable to landfills contained in part 811 of the Illinois Administrative Code (35 Ill.

Adm. Code 811)—a standard it previously adopted in part 840 of the Illinois Administrative Code

(35 Ill. Adm. Code 840)—when it promulgated standards for a specific impoundment, Ash Pond

D at the Hutsonville Power Station.

¶ 149          Dynegy argues that the Board acted arbitrarily and capriciously by requiring thicker

cover systems because it (1) failed to justify the state standard with evidence showing a thicker

cover requirement was superior to the federal standard and (2) ignored evidence that a less

stringent standard would work as well.

                                                - 39 -
¶ 150           We disagree with Dynegy and conclude that the Board stated an adequate reason

for its cover system standard.

¶ 151                                       1. Background

¶ 152                      a. The Federal and State Standards Compared

¶ 153           Under both federal and Illinois rules, an operator may elect to close a surface

impoundment by leaving the CCR in place and covering it with a final cover system consisting of

two layers. See 40 C.F.R. § 257.102(d) (2015); 35 Ill. Adm. Code 845.750 (2021). The Illinois

rule requires (1) a “low permeability layer” (35 Ill. Adm. Code 845.750(c)(1) (2021)) and (2) a

“final protective layer” (id. § 845.750(c)(2)). The low permeability layer must consist of either

(1) a compacted earth layer that is at least three feet thick or (2) a geomembrane layer. Id.

§ 845.750(c)(1). The final protective layer must also be at least three feet thick. Id. § 845.750(c)(2).

Consequently, in Illinois, a final cover system comprised of a compacted earth layer and final

protective layer must be at least six feet thick. See id. § 845.750(c)(1), (2).

¶ 154           In contrast, the federal rules require (1) an “erosion layer” (similar to the “low

permeability layer”) that must contain at least 6 inches of earthen cover and (2) an “infiltration

layer” (similar to the “final protective layer”) that must be at least 18 inches. 40 C.F.R.

§ 257.102(d)(3)(i) (2015). Consequently, under the federal rule, a final cover system constructed

entirely of compacted earth must be at least two feet thick. See id. Put another way, the state

standards require three times the thickness of the federal rule.

¶ 155           However, the state standards do not apply if the owner or operator can demonstrate

an alternative system would “provide[ ] equivalent or superior performance” and the IEPA

approves the alternative. 35 Ill. Adm. Code. § 845.750(c)(1), (2) (2021).

¶ 156                             b. Dynegy’s Proposed Standards

                                                 - 40 -
¶ 157          During rulemaking, Dynegy argued against the proposed standard, arguing instead

for standards requiring thinner layers. In support, Dynegy offered the testimony of Rudolph

Bonaparte, who opined that, in most instances, Dynegy’s proposed thinner standards would satisfy

the performance standards of section 845.750(a), but under certain circumstances it might “be

necessary to supplement [the standard] components with one or more additional engineering

measures to achieve the performance standards.

¶ 158          Dynegy also offered the testimony of David Hagen, who opined that Dynegy’s

proposed standards would “not have an effect on the amount of percolation/infiltration when

compared to the part 845 prescribed cap and cover system.” Under at least one of the

hydrogeological modeling approaches Hagen used, Dynegy’s proposed rule could be more

protective against percolation than the part 845 standard.

¶ 159          c. The Board’s Explanation for Adopting the Standard and Findings

¶ 160          In the second-notice order, the Board (1) explained its basis for adopting the section

845.750(c) standards and (2) made formal findings.

¶ 161                   i. The Board’s Discussion of Dynegy’s Objection

¶ 162          The Board noted that Dynegy had presented expert testimony to support reducing

the requirement for the low permeability and final protective layers from 36 inches to 18 inches.

It cited the testimony of Bonaparte and Hagen, noting that (1) Bonaparte testified covers on

impoundments settle much less than those in landfills and (2) Hagen had used groundwater

modeling to conclude that thinner cover layers would not increase the amount of water entering

the impoundments.

¶ 163                  ii. The Board’s Discussion of the IEPA’s Response

                                               - 41 -
¶ 164          According to the Board, the “IEPA maintain[ed] that the proposed final cover

standards are not overly protective because[,] unlike landfills[,] ‘existing CCR surface

impoundments closed with CCR in place have no low permeability liners and no leachate

collection and removal systems.’ ” The Board further explained that the IEPA’s objection was

based on Bonaparte’s testimony that Dynegy’s proposed standards may not meet the performance

standards of section 845.750(a)(1), which required “minimiz[ation] *** [of] post-closure

infiltration of liquids into the waste and releases of CCR, leachate, or contaminated run-off to the

ground or surface waters.” Id. § 845.750(a)(1). According to the Board, the IEPA asserted that it

was “not protective of groundwater to utilize a final cover which may or may not meet the

performance standards and simply rely on one or more engineering measures.”

¶ 165                                 iii. The Board’s Findings

¶ 166          The Board concluded the lack of low permeability liners in most Illinois

impoundments justified standards more stringent than those of the federal rule. The Board noted

that it derived its cover standards from the part 811 landfill standards, “which have been

implemented for over 25 years” and which, in 2011, the Board had “found *** appropriate for the

closure of *** Ashpond D.”

¶ 167          The Board rejected Dynegy’s proposal for thinner layers. Noting Bonaparte’s

testimony, the Board found that Dynegy’s proposal would not satisfy its goal of creating a rule of

general applicability capable of satisfying the protection standards at every site. It described the

landfill rule as a “well-proven design standard” that would meet standards at all locations. The

Board also noted that its rule permitted operators to petition for appropriate less stringent standards

for “site-specific reasons.”

¶ 168                                       2. This Case

                                                - 42 -
¶ 169          Dynegy argues that (1) no evidence was presented during rulemaking justifying the

Board’s decision to impose final cover system requirements derived from landfill standards that

exceeded the requirements of the federal rule and (2) the Board ignored expert testimony

supporting Dynegy’s proposal for thinner layers. We disagree.

¶ 170          In the second-notice order, the Board provided a proper basis for its adoption of

standards more stringent than the federal ones. The Board explained that “most existing CCR

surface impoundments that will be closed in place have no low permeability liners.” As a result,

the Board believed that the proposed three-foot thickness for each layer, which was based upon

landfill standards in place for over 25 years and which were implemented at the Hutsonville power

plant, was necessary.

¶ 171          The Board’s explanation demonstrates that it (1) considered Illinois’s unique

circumstances, which it was obligated to do through its section 22.59 legislative mandate to

promulgate rules protective of Illinois’s environment (see 415 ILCS 5/22.59 (West 2020)), and

(2) relied on its experience with closure standards previously implemented at a specific

impoundment.

¶ 172          We disagree with Midwest that the Board’s decision (1) was unsupported by

evidence and (2) ignored Dynegy’s evidence to the contrary. The Board’s written findings

demonstrate that the Board gave ample consideration to the testimony of Bonaparte and Hagen. In

fact, Bonaparte’s testimony provided justification for the Board’s decision to impose the stricter

standards.

¶ 173          The Board also considered (1) evidence that existing impoundments lack low

permeability layers, increasing the risk to groundwater and (2) the Board’s own experience with

the prior imposition of the stricter landfill standards at the Hutsonville impoundment. The Board

                                              - 43 -
was free to assess the weight to be given to the various pieces of evidence and to ultimately decide

that establishing more protective rules, particularly when setting default standards in rules of

general applicability, was the better course.

¶ 174          We further note, as the Board points out in its brief, that section 845.750(c) sets

only the default standards for final cover system thickness and allows the owner or operator to

petition for lower standards upon proof that thinner layers would provide equal or superior

performance. See 35 Ill. Adm. Code 845.750(c) (2021). Accordingly, by providing for site-specific

adjustments, it cannot be said that the Board did not take into account Hagen’s testimony. To the

contrary, section 845.750(c) in its entirety appears to account for (1) evidence that most

impoundments in Illinois lack low-permeability layers and (2) Bonaparte’s and Hagen’s testimony

that thinner layers may not provide adequate protection in some circumstances but may provide

adequate protection in others. Accordingly, the Board acted reasonably by both (1) setting more

protective default standards and (2) allowing for site-specific adjustment.

¶ 175                 F. Technical Feasibility and Economic Reasonableness

¶ 176          As we have noted, the Board’s decision adopting a rule may be arbitrary and

capricious if the Board failed to comply with section 27(a) of the Act (see Waste Management,

231 Ill. App. 3d at 285-89), which requires an agency, when promulgating a regulation under the

Act, to “take into account *** the technical feasibility and economic reasonableness of measuring

or reducing the particular type of pollution.” 415 ILCS 5/27(a) (West 2020).

¶ 177          Midwest and Dynegy argue that the Board failed to consider the technical

feasibility and economic reasonableness of (1) the definition of CCR surface impoundment, (2) the

requirement for monthly groundwater monitoring, (3) the liner removal requirement, and (4) the

final cover system specifications.

                                                - 44 -
¶ 178           We disagree and conclude that the Board satisfied its obligation to take into account

the technical feasibility and economic reasonableness of part 845, including the challenged

provisions.

¶ 179            1. The Applicable Law: Granite City v. Pollution Control Board

¶ 180           In Granite City, 155 Ill. 2d at 155, the petitioners, a collection of steel companies,

challenged the Board’s amendments to its water quality standards adopted in a rulemaking

proceeding. Specifically, the petitioners asserted that the Board’s rulemaking was invalid because

the Board failed to consider the technical feasibility and economic reasonableness of compliance

with the proposed regulations, in violation of section 27(a) of the Act. Id. at 156.

¶ 181           The supreme court first noted, as we have also observed, that “the Board’s

promulgation of *** regulations is a quasi-legislative function [that] will not be disturbed unless

the Board’s action is clearly arbitrary, unreasonable or capricious.” Id. at 180. The court continued,

“When acting in its quasi-legislative capacity, the Board has no burden to support its conclusions

with a given quantum of evidence” and “the burden is on [the] petitioners to establish the invalidity

of the regulations.” Id.

¶ 182           The supreme court also observed in that case that the overarching purpose of the

Act was “ ‘to establish a unified, statewide program supplemented by private remedies, to restore,

protect and enhance the quality of the environment, and to assure that adverse effects upon the

environment are fully considered and borne by those who cause them.’ ” (Emphasis in original.)

Id. at 182 (quoting Ill. Rev. Stat. 1989, ch. 111½, ¶ 1002(b)). Moreover, the Act required its terms

to be liberally construed to achieve this overarching purpose. Id. (citing Ill. Rev. Stat. 1989, ch.

111½, ¶ 1002(c)).

¶ 183          Accordingly, the supreme court concluded as follows:

                                                - 45 -
       “Pursuant to section 5(b) of the Act [citation], the Board has authority to

establish environment control standards and, in doing so, the Board must ‘take into

account’ the factors enumerated in section 27(a) ***. Clearly, the authority granted

to the Board is a general grant of very broad authority and encompasses that which

is necessary to achieve the broad purposes of the Act. The factors set forth in section

27(a) which the Board must consider in promulgating regulations, including the

technical feasibility and economic reasonableness of compliance, do not control the

Board’s authority to adopt a regulation. Rather than imposing a specific evidentiary

burden on the Board, *** section 27(a) provides general standards to guide the

Board in the exercise of its broad authority to ensure that the regulations adopted

by the Board are reasonable.

       Certainly, the Board’s broad rulemaking authority is not limited by the

extent of hardship that a regulation may cause to dischargers. The Board need not

conclude that compliance with a proposed regulation is ‘technically feasible and

economically reasonable’ before it can adopt such regulation. [Citation.] In fact,

under certain circumstances, the Board can promulgate standards which it has

found to be technically infeasible. [Citation.] If the Board, in its discretion and

based on its technical expertise, determines that a proposed regulation is necessary

to carry out the purpose of the Act, it may adopt technology-forcing standards

which are beyond the reach of existing technology. [Citation.] ***

       Indeed, the Act specifically provides for variance and adjusted standard

procedures by which the Board may relieve a discharger from compliance with its

                                - 46 -
               environmental control standards upon a showing of unreasonable economic or

               individual hardship.” Id. at 182-83.

¶ 184          The supreme court summarized its holding as follows:

               “[W]e conclude that section 27(a) does not impose specific evidentiary

               requirements on the Board, thereby limiting its authority to promulgate only

               regulations that it has determined to be technically feasible and economically

               reasonable. Rather, section 27(a) requires only that the Board consider or take into

               account the factors set forth therein. The Board must then use its technical expertise

               and judgment in balancing any hardship that the regulations may cause to

               dischargers against its statutorily mandated purpose and function of protecting our

               environment and public health.” Id. at 183.

¶ 185          The supreme court further concluded that the Board did consider the technical

feasibility and economic reasonableness of the regulations, pointing to the Board’s statement in its

final order that it had done so. Notably, in its brief findings on this subject, the Board observed

that “ ‘it [was] reasonable to conclude that implementation of [the regulations] will have costs

ranging upwards of several million dollars per year now and into the foreseeable future.’ ” Id. at

184. Nonetheless, according to the Board, this cost was reasonable when weighed against the

expected benefit of an improved aquatic environment and the benefit to human health through the

reduced presence of toxic substances. Id.

¶ 186          The supreme court closed with an observation that “the Board’s determination that

compliance is economically reasonable is a matter within its technical expertise and its discretion.

We will not act as a superagency and interfere with the Board’s judgment in this area.” Id. The

court upheld the regulations. Id. at 185.

                                               - 47 -
¶ 187                                           2. This Case

¶ 188          In the present case, the Board addressed economic reasonableness and technical

feasibility in its final order. First, the Board noted that it had requested an economic impact study

from the DCEO but received no response. Next, the Board observed that 74 power-generating

facilities in the State had existing, active, or inactive CCR surface impoundments and could be

affected by the part 845 regulations.

¶ 189          The Board then addressed the technical feasibility of part 845, noting in particular

that operators were already required under federal regulations “to install groundwater monitoring

systems, conduct periodic groundwater monitoring, create closure and post-closure care plans, and,

if necessary, conduct corrective action.” The Board then noted that the final cover system

requirements of part 845 were based upon part 811 landfill standards that were found to be

appropriate in part 840 for the closure of the Hutsonville Ashpond D. The Board stated that both

parts 811 and 840 had been found to be technically feasible. Last, the Board noted that “certain

technical aspects of these rules that differ from the federal rules are based on existing regulations

for landfills and site-specific rulemaking for CCR surface impoundments. Therefore, the Board

finds that part 845 is technically feasible.”

¶ 190          The Board also specifically addressed the economic reasonableness of part 845.

The Board noted that the Act mandated the collection of fees and included provisions for financial

assurance for all CCR surface impoundments that would be regulated by part 845. Higher fees

would be imposed for units that had not yet initiated closure and lower fees would be imposed for

units that had already completed closure. The Board also noted, similar to the technical feasibility

considerations, that “many of the technical elements of Part 845 [were] already required under

federal law, [and] others are consistent with the Board’s existing waste disposal regulations under

                                                   - 48 -
Parts 811 and 840 that have been found to be economically reasonable.” Accordingly, the Board

concluded that its adopted rules were also economically reasonable.

¶ 191           As Granite City illustrates, petitioners bear the burden of showing that the Board

failed to consider at all the technical feasibility and economic reasonableness of the part 845

regulations. We conclude that petitioners have failed to meet this burden because the Board’s

written findings show that the Board did consider, or take into account, the technical feasibility

and economic reasonableness of the part 845 regulations.

¶ 192                          G. Retroactive Application of Part 845

¶ 193           Ameren argues that the definitions of “Inactive CCR surface impoundment” and

“Inactive Closed CCR surface impoundment” have an improper retroactive effect that the

legislature did not explicitly authorize in section 22.59(g). See 415 ILCS 5/22.59(g) (West 2020).

Accordingly, Ameren asserts, any portions of part 845 that retroactively regulate the closure and

post-closure care of sites that were closed prior to the effective date of section 22.59(g) are invalid.

¶ 194          The Board responds that (1) part 845 imposes only prospective standards and

(2) even if part 845 had retroactive application, the legislature authorized such application.

¶ 195                                 1. Additional Background

¶ 196          Section 22.59(g) of the Act authorized the Board to promulgate comprehensive

rules governing CCR surface impoundments that are at least as protective as the federal

regulations. Id. The effective date of section 22.59(g) was July 30, 2019. Id.

¶ 197          The federal regulations governing the disposal of CCR are found in federal part

257, subpart D. See 40 C.F.R. §§ 257.50 to 257.107 (2015). Subpart D regulations do not apply to

“electric utilities or independent power producers that have ceased producing electricity prior to

October 19, 2015.” Id. § 257.50(e). Subpart D also states that it applies to “inactive CCR surface

                                                 - 49 -
impoundments at active electric utilities or independent power producers.” (Emphasis added.) Id.

§ 257.50(c). This provision effectively exempts from regulation inactive surface impoundments at

inactive facilities, commonly referred to as “legacy ponds.”

¶ 198          As we have already discussed above (supra ¶ 52), environmental groups challenged

the legacy pond exemption in USWAG. The USWAG court recognized that the exemption of

“legacy ponds” from federal regulation meant that inactive impoundments at inactive facilities

were subject to notably less stringent regulation than inactive impoundments at active facilities.

USWAG, 901 F.3d at 432. Because “[t]he risks posed by legacy ponds are at least as substantial as

inactive impoundments at active facilities,” the USWAG court (1) held that the USEPA acted

arbitrarily and capriciously by exempting legacy ponds, (2) vacated the exemption, and

(3) remanded the vacated portions of part D. Id. at 433-34, 449.

¶ 199          To date, the USEPA has not replaced or amended the vacated provision.

¶ 200          When promulgating the state regulations, the Board adopted the following

definitions, which Ameren challenges in this appeal:

                       “ ‘Inactive CCR surface impoundment’ means a CCR surface impoundment

               in which CCR was placed before but not after October 19, 2015 and still contains

               CCR on or after October 19, 2015. Inactive CCR surface impoundments may be

               located at an active facility or inactive facility.

                       ‘Inactive Closed CCR surface impoundment’ means an inactive CCR

               surface impoundment that completed closure before October 19, 2015 with an

               Agency-approved closure plan.” 35 Ill. Adm. Code 845.120 (2021).

¶ 201          Ameren contends that the Board’s inclusion of October 19, 2015 (the effective date

of the federal regulations) as the cutoff date to consider CCR surface impoundments closed under

                                                 - 50 -
the state regulations imposes improper retroactive obligations on CCR surface impoundments that

Ameren closed (pursuant to state-approved closure plans) after October 19, 2015, but prior to July

30, 2019 (the effective date of the section 22.59(g) enabling legislation).

¶ 202          Specifically, Ameren points in its brief to certain former ash ponds that it closed

with the approval and authority of the State prior to the enactment of section 22.59(g). For

example, following the closure of the Hutsonville Ash Pond D in 2013, Ameren used the Ash Pond

D closure plan as a road map for closing five other former ash ponds at the Hutsonville Plant.

Ameren completed closure of Hutsonville Ash Ponds A through C and the Bottom Ash Pond in

June 2015. Ameren’s closure efforts with respect to two former ash ponds at the Meredosia plant

were deemed “substantially complete” in December 2018. Ameren explains that its closure

activities at Hutsonville and Meredosia (1) cost approximately $21.6 million, (2) were taken “in

reliance on the IEPA’s approval of the closure plans,” and (3) were competed prior to the effective

date of section 22.59(g), which was July 30, 2019.

¶ 203          Ameren contends that the Board’s inclusion of “October 15, 2019,” as the cutoff

date for considering CCR impoundments to be closed imposes retroactive closure obligations on

the aforementioned impoundments that Ameren closed after October 15, 2019. Ameren argues that

because the legislature did not (1) enable the Board to promulgate rules until July 30, 2019 or

(2) expressly state the temporal reach of section 22.59(g), the Board’s regulations cannot reach

back in time to impose new regulations on impoundments that have already been deemed closed

(or substantially closed pursuant to a State-approved closure plan).

¶ 204                                 2. The Applicable Law

¶ 205          Illinois courts apply the test provided in Landgraf v. USI Film Products, 511 U.S.

244 (1994), to determine whether a statute may be applied retroactively. See Commonwealth

                                               - 51 -
Edison Co. v. Will County Collector, 196 Ill. 2d 27, 39, 749 N.E.2d 964, 972 (2001). The Illinois

Supreme Court has explained that, by adopting the Landgraf approach, the court “ ‘switched the

focus of the *** retroactivity analysis from “vested rights” to legislative intent.’ ” Perry v.

Department of Financial & Professional Regulation, 2018 IL 122349, ¶ 39, 106 N.E.3d 1016

(quoting Doe A. v. Diocese of Dallas, 234 Ill. 2d 393, 411, 917 N.E.2d 475, 486 (2009)).

¶ 206          “Under step one of Landgraf, a court first determines whether the legislature has

expressly prescribed the temporal reach of the new law.” (Internal quotation marks omitted.) Id.

¶ 40 (citing Commonwealth Edison, 196 Ill. 2d at 39-40). “If the legislature has clearly indicated

the temporal reach, then such temporal reach must be given effect unless to do so would be

constitutionally prohibited.” Id.

¶ 207          However, “Illinois courts need not go beyond step one of the Landgraf approach”

because “if the temporal reach has not been clearly indicated within the text of the new law, then

the legislature’s intent as to temporal reach is provided by default in section 4 [of the Statute on

Statutes (5 ILCS 70/4 (West 2016))].” Id. ¶ 41.

¶ 208          “Section 4 is a general savings clause, which [the supreme court] has interpreted as

meaning that procedural changes to statutes will be applied retroactively, while substantive

changes are prospective only.” (Internal quotation marks omitted.) Id. ¶ 43. That is to say, under

Illinois law, “where the legislature has not expressly indicated its intent as to temporal reach, a

presumption arises that the amended statute is not to be applied retroactively.” (Internal quotation

marks omitted.) Id. ¶ 42.

¶ 209                                      3. This Case

¶ 210          Ameren argues that the Board cannot promulgate regulations with retroactive effect

unless the authorizing statute has explicitly granted the Board that power. Ameren further contends

                                               - 52 -
that because section 22.59(g)(1) does not contain an explicit statement of the temporal scope for

the regulations it authorizes, section 4 of the Statute on Statutes (5 ILCS 70/4 (West 2020)) applies

to bar the Board from promulgating regulations with retroactive effect. Accordingly, Ameren

concludes that the Board lacked authority to utilize October 19, 2015, as the triggering date to

determine a unit’s closure status. We disagree.

¶ 211          We construe section 22.59(g) as authorizing regulations imposing new duties on

existing impoundments when necessary to effectuate the purpose of the Act to restore and protect

the environment. Moreover, Ameren has failed to show retroactive effect.

¶ 212          a. Section 22.59, Liberally Construed, Authorizes New Duties on Existing

                                           Impoundments

¶ 213          “The scope of authority conferred on [an agency] by its enabling legislation is a

question of statutory interpretation that [the court] review[s] de novo.” Genius v. County of Cook,

2011 IL 110239, ¶ 25, 953 N.E.2d 407. Nevertheless, regulations adopted by an administrative

agency are presumptively valid. Medponics Illinois, LLC v. Department of Agriculture, 2021 IL

125443, ¶ 31, 183 N.E.3d 79. Furthermore, when the legislature directs that a provision “be

‘liberally construed’ to carry out the purpose and policy expressly set forth therein,” a court should

heed that directive. See In re Shelby R., 2013 IL 114994, ¶ 32, 995 N.E.2d 990 (requiring a court

to heed such a provision in the Juvenile Court Act of 1987 (705 ILCS 405/1-1 et seq. (West

2010))).

¶ 214          Section 22.59(a) (415 ILCS 5/22.59(a) (West 2020)) sets forth the purposes of

section 22.59—namely, to “promote a healthful environment, including clean water, air, and land,

*** so as to protect public health”—and then states that, “[t]he provisions of this Section shall be

liberally construed to carry out the purposes of this Section.” Thus, section 22.59(g)’s grant of

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regulatory authority should receive liberal construction. Accordingly, a liberal construction of

section 22.59(g)(1)’s mandate that the Board promulgate rules that are “at least as protective and

comprehensive” as the federal regulations (emphasis added) (id. § 22.59(g)(1)) means permitting

retroactive amendments when they (1) promote a healthful environment and (2) are necessary to

ensure consistency with the federal rules.

¶ 215          Moreover, we agree with the Board that the legislature intended for the Board to

promulgate regulations that imposed new duties to remediate or prevent pollution of the

environment caused by past activities at existing impoundments. Specifically, the legislature found

that (1) it was the long-standing policy of the State “to restore, protect, and enhance the

environment,” (2) “CCR generated by the electric generating industry has caused groundwater

contamination and other forms of pollution at active and inactive plants throughout this State,”

and (3) “environmental laws should be supplemented to ensure consistent, responsible regulation

of all existing CCR surface impoundments.” (Emphases added.) Id. § 22.59(a). The legislature

chose not to exempt inactive or dry impoundments from regulation, emphasizing that the

provisions of section 22.59(a) “shall apply, without limitation, to all existing CCR surface

impoundments and any CCR surface impoundments constructed after the [July 30, 2019,] effective

date of [the enabling legislation].” (Emphasis added.) Id. § 22.59(m).

¶ 216          Although the legislature did not use the word “retroactive” in section 22.59(g), the

plain language the legislature did employ—particularly when liberally construed in favor of

protecting the environment—clearly shows that the legislature intended that where the Board

deemed appropriate, new duties could be imposed on existing impoundments.

¶ 217                    b. Ameren Has Not Shown Retroactive Effect

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¶ 218          Nonetheless, Ameren has not shown that the use of October 19, 2015, as the cutoff

date for deeming an impoundment closed has a retroactive effect. A unit’s closure status on a

particular date is simply an antecedent fact, or preceding circumstance, which we discuss further

below. Ameren has not offered any authority or argument suggesting the use of antecedent facts

to determine when a rule applies is a retroactive application of a law under a section 4 analysis.

¶ 219          To the contrary, the supreme court’s analysis in Hayashi v. Illinois Department of

Financial & Professional Regulation, 2014 IL 116023, ¶ 25, 25 N.E.3d 570, suggests that Illinois

law does not deem use of an antecedent fact as a trigger for a penalty to be a form of retroactivity.

In Hayashi, the plaintiffs argued that an amendment to a professional licensing statute was

“retroactive as applied to them because their health care licenses were revoked as a consequence

of their [pre-amendment] convictions.” Id. The new statute’s “reliance on convictions predating

its enactment [did] not render it retroactive as that term has been defined in case law.” Id.

                       “Although the [amended law] relies upon antecedent facts—plaintiffs’

               convictions—for its operation, it does not apply retroactively to them. [Part of the

               new law] defines new per se eligibility requirements with which licensees must

               comply in order to practice their health care professions in Illinois. The [amended

               law] does not ‘reach back in time’ to change the criminal penalties imposed on

               plaintiffs’ convictions, nor does it render unlawful conduct that was lawful at the

               time it was committed. [Citation.]” Id. ¶ 26.

¶ 220          Similarly, in International Union of Operating Engineers Local 965 v. Illinois

Labor Relations Board, State Panel, 2015 IL App (4th) 140352, ¶ 30, 30 N.E.3d 1191, this court

reiterated that “[a] statute does not operate retrospectively merely because it is applied [to] conduct

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antedating the statute’s enactment, [citation], or upsets expectations based in prior law.” (Internal

quotation marks omitted.)

¶ 221          Ameren cannot satisfy its burden to show the definition of an inactive closed

impoundment applies retroactively if it cannot show that Illinois law has treated the sort of

provision at issue as retroactive in some circumstance. Because Ameren cannot show that the use

of a unit’s closure status on October 15, 2015, to determine that the applicable regimen is

“retroactive” in the sense used in section 4 of the Statute on Statutes, the entire argument fails.

¶ 222          For the reasons stated, we hold that Ameren has failed to meet its burden to show

that the Board exceeded its statutory authority under the amendments when it used the units’

closure status as of part 257’s October 19, 2015, effective date to determine the regulations to

which particular units were subject.

¶ 223                                   III. CONCLUSION

¶ 224          For the reasons stated, we affirm the final order of the Board.

¶ 225          Affirmed.

                                                - 56 -
 Midwest Generation, LLC v. Illinois Pollution Control Board, 2024 IL App (4th) 210304

Decision Under Review:      Petition for review of order of the Illinois Pollution Control
                            Board, No. R20-19.

Attorneys                   Kristen L. Gale, Susan M. Franzetti, and Vince Angermeier, of
                            Nijman Franzetti LLP, of Chicago, for appellant Midwest Gen-
for                         eration, LLC.
Appellant:                  Michael L. Raiff, of Gibson, Dunn & Crutcher LLP, of Dallas,
                            Texas, and Joshua R. More, Robert A.H. Middleton, and Sarah
                            L. Lode, of ArentFox Schiff LLP, of Chicago, for appellants
                            Dynegy Midwest Generation, LLC, Illinois Power Generating
                            Company, Illinois Power Resources Generating, LLC, Electric
                            Energy, Inc., and Kincaid Generation, LLC.

                            Claire A. Manning, Anthony D. Schuering, and Garrett L. Kin-
                            kelaar, of Brown, Hay & Stephens, LLP, of Springfield, for
                            other appellants.

Attorneys                   Kwame Raoul, Attorney General, of Chicago (Jane Elinor Notz,
                            Solicitor General, and Jonathan J. Sheffield, Assistant Attorney
for                         General, of counsel), for appellee.
Appellee:

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