Heating, Air-Conditioning, & Refrigeration Distributors International v. EPA ( 2023 )


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  •  United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued November 18, 2022              Decided June 20, 2023
    No. 21-1251
    HEATING, AIR CONDITIONING & REFRIGERATION
    DISTRIBUTORS INTERNATIONAL, ET AL.,
    PETITIONERS
    v.
    ENVIRONMENTAL PROTECTION AGENCY AND MICHAEL S.
    REGAN, IN HIS OFFICIAL CAPACITY AS ADMINISTRATOR OF THE
    U.S. ENVIRONMENTAL PROTECTION AGENCY,
    RESPONDENTS
    Consolidated with 21-1252, 21-1253
    On Petitions for Review of a Final Action
    of the Environmental Protection Agency
    Stephen K. Wirth and Wayne J. D’Angelo argued the
    causes for Association Petitioners and Petitioner Worthington
    Industries, Inc. With them on the briefs were Ethan G.
    Shenkman and Jonathan S. Martel. Zachary J. Lee entered an
    appearance.
    2
    David M. Williamson argued the cause and filed the briefs
    for petitioner Choice Refrigerants.
    Andrew S. Coghlan, Attorney, U.S. Department of Justice,
    argued the cause for respondents. On the brief were Todd Kim,
    Assistant Attorney General, and Eric G. Hostetler, Attorney.
    Melissa J. Lynch and David Doniger were on the brief for
    amicus curiae Natural Resources Defense Council in support
    of respondents.
    Before: HENDERSON, PILLARD and WALKER, Circuit
    Judges.
    Opinion for the Court filed by Circuit Judge WALKER.
    Opinion concurring in part and dissenting in part filed by
    Circuit Judge PILLARD.
    WALKER, Circuit Judge: Fridges, freezers, and air-
    conditioning are technological marvels, making our lives much
    more comfortable. But those amenities rely on harmful
    greenhouse gases called hydrofluorocarbons — HFCs for
    short.
    According to the Environmental Protection Agency, those
    gases threaten the environment because they “can be hundreds
    to thousands of times more potent than carbon dioxide.” 
    86 Fed. Reg. 55,123
     (Oct. 5, 2021). To reduce their use, Congress
    enacted the American Innovation and Manufacturing Act. 
    42 U.S.C. § 7675
    . The Act directs the EPA to pass a rule phasing
    them out. 
    Id.
     § 7675(e).
    After the EPA passed that rule, two regulated companies
    and three trade associations sought judicial review. They say
    3
    that the agency exceeded its statutory authority in two different
    ways, and that the Act violates the nondelegation doctrine.
    One of the statutory arguments fails, as does the
    nondelegation challenge. But the remaining argument has
    merit: The EPA lacked statutory authority to pass two measures
    regulating the distribution of HFCs. So we vacate those parts
    of the EPA’s rule and remand to the agency.
    I. Background
    A. Congress Tasked the EPA with Reducing HFC Use
    The United States has long struggled with the
    environmental impact of refrigeration technology. Before
    fridges, freezers, and air conditioners used hydrofluorocarbons
    as coolants, they used chlorofluorocarbons.                 But
    chlorofluorocarbons deplete the ozone layer. So in 1990
    Congress started to phase them out. 42 U.S.C. §§ 7671a,
    7671c.
    That prompted a shift to HFCs. But Congress’s change
    swapped one environmental hazard for another. HFCs, the
    EPA says, are harmful greenhouse gases — “hundreds to
    thousands of times more potent than carbon dioxide.” 86 Fed.
    Reg. at 55,123.
    In 2020, Congress intervened again, this time passing the
    American Innovation and Manufacturing Act to phase out
    HFCs. 
    42 U.S.C. § 7675
    . The Act directs the EPA to “issue a
    final rule . . . phasing down” HFCs “through an allowance
    allocation and trading program.” 
    Id.
     § 7675(e)(3). The Act
    provides the outline for how that program will work, leaving
    the agency to fill in the details.
    4
    Here’s how it works. The EPA first calculates the baseline
    levels of HFC production and consumption in the United
    States. Id. § 7675(e)(1)(C). The agency then caps maximum
    annual HFC production and consumption at a percentage of
    those baselines — for instance, ninety percent in 2023. Id.
    § 7675(e)(2)(B), (C). Over time, the caps come down,
    eventually reaching fifteen percent in 2036. Id.
    To ensure that production and consumption stay under the
    respective caps, the Act puts in place a system of “allowances.”
    Id. § 7675(e)(2)(D). An allowance is like a license; without
    one, “no person shall . . . produce” or “consume” HFCs. Id.
    § 7675(e)(2)(A).
    Allowances are initially distributed to HFC users by the
    EPA. Once allocated, HFC users can buy and sell allowances
    from one another to adjust their production or consumption
    capacity. Id. § 7675(g). The total number of allowances in
    circulation corresponds to the current HFC production or
    consumption cap.
    Late last year, the EPA issued its final Phasedown Rule,
    implementing the cap-and-trade program. 40 C.F.R. pt. 84.
    Among other things, the Phasedown Rule calculates the annual
    production and consumption caps, explains how the agency
    will distribute allowances, and establishes reporting and
    auditing requirements for HFC consumers. Id.
    B. The Petitioners Make Three Challenges to the Rule
    The petitioners challenge three different aspects of the
    Phasedown Rule.
    5
    First, Choice Refrigerants, a manufacturer of heating and
    cooling chemicals, challenges the EPA’s authority to regulate
    HFCs within blends.
    An HFC blend is a mix of HFCs and other chemicals.
    Blends are better than plain-vanilla HFCs for some heating and
    cooling applications. Choice’s flagship product is an HFC
    blend that it manufactures abroad and imports into the United
    States.
    The EPA says mixing an HFC with another chemical does
    not exempt the HFC from the cap-and-trade program. So
    importing blends “requires expenditure of allowances,” with
    the number of “allowances necessary” determined according to
    the “components of the blend that are regulated HFCs.” JA
    1112; see also 86 Fed. Reg. at 55,133, 55,142. If that’s correct,
    Choice must buy allowances to import its blend, and its
    production costs will go up.
    Second, Choice claims that Congress impermissibly
    delegated legislative power to the EPA by giving it unguided
    discretion to distribute HFC allowances.
    The Act lists six types of HFC users — including
    “mission-critical military” users — who get preferential access
    to     the    pool     of     allowances.         
    42 U.S.C. § 7675
    (e)(4)(B)(iv)(I)(ee). The Act also lets the agency
    designate other “essential” users who should get allowances.
    
    Id.
     § 7675(e)(4)(B)(i)-(ii). But beyond that, Choice argues, the
    Act lets the EPA decide who should get the remaining
    allowances. And because the statute gives no additional
    guidance, Choice says it violates the nondelegation doctrine.
    Third, three trade associations challenge two HFC-
    distribution regulations in the EPA’s rule. The first regulation
    6
    mandates refillable cylinders to transport HFCs, thus banning
    the disposable cylinders used by the industry today. 
    40 C.F.R. § 84.5
    (h). The second regulation establishes a certification and
    tracking system for HFC distribution. 
    Id.
     § 84.23(a). Under
    that system, “any person who imports, sells, or distributes”
    HFCs “must permanently affix a QR code to the [HFC’s]
    container that documents a valid certification identification.”
    Id. § 84.23(c)(2).
    The trade associations argue that the Act does not give the
    EPA authority to pass those regulations — nowhere does the
    Act say anything about QR codes or refillable cylinders. That
    challenge is joined by Worthington Industries, the only
    domestic manufacturer of refillable and disposable cylinders.
    II. Analysis
    Under the Clean Air Act, this Court may set aside the
    EPA’s Phasedown Rule if it is “arbitrary, capricious, an abuse
    of discretion, or otherwise not in accordance with law.” 
    42 U.S.C. § 7607
    (d)(9)(A);    see    
    id.
        §§ 7607(d)(1)(I),
    7675(k)(1)(C). We “apply the same standard of review under
    the Clean Air Act as we do under the Administrative Procedure
    Act.” Maryland v. EPA, 
    958 F.3d 1185
    , 1196 (D.C. Cir. 2020)
    (cleaned up).
    Applying that standard, we vacate in part the EPA’s
    Phasedown Rule. Choice’s challenges fail: The AIM Act gives
    the EPA authority to regulate HFCs within blends, and we may
    not consider Choice’s nondelegation argument because Choice
    failed to exhaust it before the agency. But the trade
    associations’ petition fares better: The EPA does not identify a
    statutory provision authorizing its QR-code and refillable-
    cylinder rules. So we vacate those parts of the Phasedown Rule
    and remand to the agency.
    7
    A. The EPA May Regulate HFCs Within Blends
    The EPA has statutory authority to regulate HFCs within
    blends. That’s because an HFC within a blend remains a
    regulated HFC under the Act.
    Start with the EPA’s statutory authority. The AIM Act
    directs the EPA to “phas[e] down the production [and
    consumption] of regulated substances . . . through an
    allowance allocation and trading program.” 
    42 U.S.C. § 7675
    (e)(3)(A)-(B). So the EPA has authority to require
    allowances for any regulated substance. 
    Id.
     § 7675(e)(2)(A).
    The Act defines a “regulated substance” to include HFCs
    “listed” in a statutory table. Id. § 7675(b)(11), (c)(1) (table of
    regulated substances). The HFCs listed in the table are
    identified by their molecular formulas. Id.
    Under that definition, an HFC within a blend is still a
    “regulated substance” because it is chemically identical to an
    HFC outside of a blend. Both have the same molecular
    structure. As the EPA put it during notice and comment, “[t]he
    components [of a blend] are not chemically altered in [the
    blending] process.” JA 1112.
    In other words, an HFC in a blend of other chemicals is
    like a blue M&M in a bag of red M&Ms. The blue one does
    not stop being blue just because it is tossed in with a bunch of
    red ones. In the same way, an HFC mixed with other chemicals
    does not stop being a regulated substance under the Act. Cf. 
    42 U.S.C. § 7675
    (e)(4)(A)(i) (when a chemical process
    “consume[s]” an HFC to create some other chemically-distinct
    product, that product is not covered by the allowance-trading
    program).
    8
    In response, Choice argues that blended HFCs are different
    enough from unblended HFCs that they are not regulated
    substances. It says “blended products . . . have distinct
    physical and chemical properties” and “cannot be readily
    separated into their component[s] . . . without complex
    fractionation equipment.” Choice Br. 4.
    That may be true. But it does not go to whether an HFC
    within a blend has a different molecular composition than an
    unblended HFC. And when pressed at argument, Choice
    repeatedly conceded that HFCs within blends are chemically
    identical to HFCs outside of a blend.
    Finally, Choice notes that under the Act, the EPA may not
    “designate as a regulated substance a blend of substances that
    includes a[n] [HFC] for purposes of phasing down production
    or consumption of regulated substances.”                 
    42 U.S.C. § 7675
    (c)(3)(B)(i).      But that provision conditions the
    Administrator’s authority to list new HFCs as “regulated
    substances” subject to the allowance-trading program. 
    Id.
    § 7675(c)(3)(A). Here, the EPA has not exercised that
    authority, let alone used it to list a blend as a regulated HFC. It
    has instead regulated already-listed HFCs within a blend. And
    the Act confirms that the prohibition on listing blends “does
    not affect the authority of the Administrator to regulate under
    this Act a regulated substance within a blend of substances.”
    Id. § 7675(c)(3)(B)(ii) (emphasis added).
    B. Choice Failed to Exhaust Its Nondelegation Challenge
    Next, Choice says Congress impermissibly delegated its
    legislative authority to the EPA. See 86 Fed. Reg. at 55,142
    (noting EPA’s “considerable discretion” in allocating
    allowances under the AIM Act), 55,203 (final rule allocating
    9
    allowances).  But because Choice failed to make its
    nondelegation argument to the EPA during notice and
    comment, Choice may not raise that argument now.
    Choice sues under § 307 of the Clean Air Act, which
    “appl[ies] to” the AIM Act. 
    42 U.S.C. § 7675
    (k)(1)(C). That
    cause of action has an exhaustion requirement: a litigant may
    raise in court only “an objection to a rule or procedure which
    was raised with reasonable specificity during the period for
    public comment.” 
    Id.
     § 7607(d)(7)(B).
    Choice concedes that it did not raise its nondelegation
    argument during notice and comment. Instead, it says it did not
    need to exhaust its nondelegation argument because it is an
    objection to the statute and not an “objection to a rule or
    procedure” subject to exhaustion. Id. § 7607(d)(7)(B).
    That argument collapses under scrutiny. The Clean Air
    Act’s cause of action authorizes only a limited category of
    suits: “petition[s] for review of action of the Administrator [of
    the EPA].” Id. § 7607(b)(1) (emphasis added). So litigants
    using the Clean Air Act’s cause of action must bring challenges
    to agency action, not free-floating challenges to statutes.
    Statutes are passed by Congress, not the “Administrator [of the
    EPA].” Id.
    Thus, to the extent that Choice’s suit is an objection to the
    AIM Act alone, Choice fails to state a claim under the Clean
    Air Act. And to the extent Choice is challenging the
    Phasedown Rule, the Clean Air Act’s exhaustion requirement
    applies. 
    42 U.S.C. § 7607
    (d)(7)(B). Either way, Choice’s
    nondelegation claim is not properly before us.
    That said, Choice’s petition is best read as a challenge to
    the EPA’s rule. In substance, its argument is that the EPA’s
    10
    rule is unlawful because the statute authorizing it is an
    unconstitutional delegation of legislative power. Indeed,
    Choice characterizes its argument that way in its brief. It lists
    the “ruling[ ] under review” as the “Cap-and-Trade Rule” and
    it asserts that “[t]his Court has jurisdiction . . . to review EPA’s
    final rule.” Choice Br. ii, 1. Because Choice’s challenge is to
    the Phasedown Rule, any objections to that rule had to be made
    first to the EPA. 
    42 U.S.C. § 7607
    (d)(7)(B). Choice did not
    do that here. So we may not consider its nondelegation claim
    now.
    Requiring litigants to first bring nondelegation challenges
    to the EPA may seem futile. After all, the agency cannot
    change Congress’s grant of broad discretion. 1 But the Clean
    Air Act’s exhaustion rule has no exception for futile
    challenges. Texas Municipal Power Agency v. EPA, 
    89 F.3d 858
    , 876 (D.C. Cir. 1996) (per curiam) (no futility exception);
    see also Lead Industry Association Inc. v. EPA, 
    647 F.2d 1130
    ,
    1172-74 (D.C. Cir. 1980) (no exception for constitutional
    challenges to the rulemaking process). 2
    1
    The agency could, in the rulemaking process, decide for itself that
    a statute unconstitutionally delegates too much power, rendering a
    rule unlawful. Cf. U.S. Const., art. II (the executive branch, acting
    under the President, has a duty to “take Care that the Laws be
    faithfully executed”).
    2
    True, some constitutional challenges to agency action may be
    brought directly in district court — even if a statute requires other
    run-of-the-mill challenges to be first litigated before the agency. See
    Axon Enterprise, Inc. v. Federal Trade Commission, 
    143 S. Ct. 890 (2023)
    . But that doesn’t excuse Choice from the Clean Air Act’s
    exhaustion requirement here. When litigants choose to use a
    statutory review mechanism like the Clean Air Act’s, they must still
    meet its strictures. So even if Choice could have bypassed the Act’s
    exhaustion requirement by bringing its nondelegation claim directly
    11
    C. The Refillable-Cylinder and QR-Code Rules Lack
    Statutory Basis
    Finally, the trade associations and Worthington argue that
    the EPA’s refillable-cylinder and QR-code rules lack a
    statutory basis. We agree. The EPA has not identified a
    provision of the AIM Act giving it the authority to require
    refillable cylinders or a QR-code tracking system. 
    40 C.F.R. §§ 84.5
    (h), 84.23(a).
    To support those regulations, the EPA attempts to rely on
    two provisions of the AIM Act. It initially points to Section
    7675(k)(1)(A), which gives the agency authority to
    “promulgate . . . such regulations as are necessary to carry out
    the functions of the [EPA] under [the AIM Act].” The EPA
    recognizes that (k)(1)(A) is a source of procedural not
    substantive authority — it lets the agency pass rules to carry
    out powers granted by other provisions of the statute.
    For substantive authority, the EPA relies on Section
    7675(e)(2)(B):
    (B) Compliance
    For each year [of the phasedown period],
    the Administrator shall ensure that the
    annual quantity of all regulated substances
    produced or consumed in the United States
    does not exceed the product obtained by
    multiplying —
    in district court (we take no position on whether it could), it did not
    do that here.
    12
    (i) the      production     baseline      or
    consumption baseline, as applicable;
    and
    (ii) the applicable percentage listed on the
    table contained in subparagraph (C).
    Relying on Congress’s instruction to “ensure” that HFC
    production and consumption “do[ ] not exceed” the phasedown
    cap, the EPA’s final rule claimed the “authority to establish
    complementary measures . . . [to] meet the statutory reduction
    [target],” 86 Fed. Reg. at 55,172 (citing 
    42 U.S.C. § 7675
    (e)(2)(B)).
    But the EPA’s reading has two major problems: It ignores
    the role that subsection (e)(2)(B) plays in the statutory scheme
    and it reads too much into the word “ensure.”
    To start, subsection (e)(2)(B) is a math equation, not a
    grant of regulatory power. It tells the agency how to calculate
    the production and consumption cap for each year of the
    phasedown.       To calculate the cap, the agency must
    “multiply[ ]” the “production baseline or consumption
    baseline” by the “applicable percentage listed on the table” in
    (e)(2)(C). 
    42 U.S.C. § 7675
    (e)(2)(B).
    Confirming that reading, statutory cross-references treat
    (e)(2)(B) as a formula setting the cap for each year of the
    phasedown. For example, subsection (e)(2)(D)(i) instructs the
    EPA to “determine the quantity of allowances . . . that may be
    used for the following calendar year” by referring to the cap
    “calculated under” (e)(2)(B).          
    Id.
     § 7675(e)(2)(D)(i).
    Similarly, under (e)(5), the EPA may allow an HFC producer
    to make more HFCs than authorized by his “production
    allowances” if doing so “would not violate” the cap in
    (e)(2)(B). Id. § 7675(e)(5), (B)(iii).
    13
    Given the role that (e)(2)(B) plays in the statutory scheme,
    that subsection would be an odd place for Congress to locate a
    grant of sweeping regulatory power letting the agency pass
    additional measures to phasedown HFCs. True, the placement
    of statutory language is only one part of the puzzle. Courts
    must vindicate the plain meaning of the text wherever it is
    placed in the statute. But here the statutory text does not
    support the EPA’s assertion of power.
    Reading subsection (e)(2)(B) to grant the EPA authority to
    pass complementary measures leans heavily on the word
    “ensure.” The EPA asserts that (e)(2)(B)’s use of “shall
    ensure” reflects Congress’s “intentional effort to confer the
    flexibility necessary [for] the agency to accomplish the
    statute’s aims” and so gives the EPA “more general authority
    to establish complementary measures to ensure that the
    statutory phasedown is achieved.” EPA Br. 52 (cleaned up).
    We disagree. To “ensure” is “to make sure, certain, or
    safe.” Ensure (def. 1), Merriam-Webster (2023). So when
    Congress told the EPA to “ensure” that the annual HFC
    consumption cap is not “exceed[ed],” all it said was that the
    agency should guarantee that result. 42 U.S.C. § (e)(2)(B).
    Subsection (e)(2)(B) does not tell the agency anything about
    how to “ensure” the cap is met.
    The rest of the statute does that job. Congress gave the
    EPA the power to ensure the cap is met by using the allowance-
    trading program, id. § 7675(e), detailed statutory auditing and
    reporting requirements, id. § 7675(d), and the EPA’s power to
    pass rules regulating “practice[s], process[es], or activit[ies]”
    for “servicing, repair[ing], dispos[ing of], or install[ing] [HFC]
    equipment,” id. § 7675(h)(1).
    14
    Those detailed instructions undercut the agency’s claim
    that (e)(2)(B) gives it power to pass other measures. When
    “draftsmen[ ] mention . . . one thing, like a grant of authority”
    it “necessarily, or at least reasonably, impl[ies] the preclusion
    of alternatives.” Shook v. D.C. Financial Responsibility and
    Management Assistance Authority, 
    132 F.3d 775
    , 782 (D.C.
    Cir. 1998). Congress’s exhaustive instructions to the agency
    throughout the AIM Act make it less plausible that Congress
    meant the words “shall ensure” in (e)(2)(B) to give the EPA
    broad power to pass new rules.
    That intuition becomes even stronger when we consider
    the breadth of the EPA’s claimed power. The refillable-
    cylinder rule alone is likely to impose between $ 441 million
    and $2 billion in costs on the regulated industry. 86 Fed. Reg.
    at 55,174 ($ 441 million estimate); JA 119 ($ 2 billion
    estimate). It is unlikely that Congress would have granted the
    agency authority to pass a rule of that magnitude in a provision
    of the statute that says nothing about complementary measures,
    refillable cylinders, or QR Codes.
    To be clear, we do not decide this case under the major-
    questions doctrine. That doctrine holds that courts “expect
    Congress to speak clearly if it wishes to assign to an agency
    decisions of vast economic and political significance.” West
    Virginia v. EPA, 
    142 S. Ct. 2587
    , 2605 (2022) (cleaned up).
    And the EPA’s QR-code and refillable-cylinder rules are less
    important and expensive than other regulations to which the
    Supreme Court has applied that doctrine. See 
    id. at 2609
    ; NFIB
    v. OSHA, 
    142 S. Ct. 661
    , 666 (2022).
    Instead, we rely on another long-standing rule of
    interpretation: “Congress . . . does not alter the fundamental
    details of a regulatory scheme in vague terms or ancillary
    provisions.” Whitman v. American Trucking Associations, 531
    
    15 U.S. 457
    , 468 (2001). Whereas the major-questions doctrine
    has a constitutional basis — safeguarding the “separation of
    powers” by ensuring that agencies do not use statutory
    ambiguities to make decisions vested in our elected
    representatives — the American Trucking rule rests on a more
    modest intuition about how we use language. West Virginia,
    142 S. Ct. at 2609. The touchstone of statutory interpretation
    is always to “interpret the words consistent with their ordinary
    meaning at the time Congress enacted the statute.” Wisconsin
    Central Ltd. v. United States, 
    138 S. Ct. 2067
    , 2070 (2018)
    (cleaned up). Ordinary readers of English do not expect
    provisions setting out math equations to empower an agency to
    prescribe other “fundamental details of a regulatory scheme.”
    Whitman, 531 U.S. at 468.
    Because the EPA’s interpretation of (e)(2)(B) seeks to do
    just that, it strains against the ordinary use of language. That
    is an important clue that the EPA advances an implausible
    reading of the statute.
    *    *   *
    The EPA has not identified a statute authorizing its QR-
    code and refillable-cylinder regulations. We therefore vacate
    those parts of the Phasedown Rule and remand to the agency.
    We deny Choice’s challenges to other aspects of the rule.
    So ordered.
    PILLARD, Circuit Judge, concurring in part and dissenting
    in part:
    I agree with my colleagues that EPA        has the statutory
    authority to regulate hydrofluorocarbons       (HFCs) that are
    contained within blends. I also agree that     we may not hear
    Choice’s nondelegation argument because        Choice failed to
    exhaust it before the agency.
    I write separately to explain why EPA has the authority to
    require refillable cylinders for regulated HFCs and to
    implement a QR-code tracking system to trace the import, sale,
    and distribution of HFCs through the supply chain. In the
    American Innovation and Manufacturing Act, Congress
    imposed on EPA a duty to “ensure” compliance with the
    schedule Congress mandated for phasing down HFC
    production and consumption. 
    42 U.S.C. § 7675
    (e)(2)(B). The
    Act makes clear that Congress intended its phasedown
    schedule to be met. To that end, it empowered EPA to
    “promulgate such regulations as are necessary” to effect
    compliance. 
    Id.
     § 7675(k)(1)(A).
    The rule under review falls squarely within EPA’s
    congressionally delegated authority: The agency determined
    that, to accomplish the HFC phasedown, it was necessary to
    require refillable cylinders with unique, trackable QR codes, so
    it promulgated a final rule to that effect. After all, requiring
    refillable and trackable cylinders is a straightforward way to
    “ensure” that the regulated substances they contain correspond
    to allowances the statute requires. Without such tools, it is hard
    to see how EPA can ensure the phasedown.
    My colleagues’ conclusion that EPA’s duty to ensure
    compliance is nothing more than a “math equation,” Maj. Op.
    12, understates and undercuts the responsibility Congress gave
    the agency. Their reading runs counter to the statute’s text and
    structure. It will hamstring EPA’s efforts to combat illicit trade
    2
    in HFCs, making it less likely that the United States
    accomplishes the HFC reductions Congress mandated. And
    the majority’s interpretation will have unfortunate side effects
    for domestic industry and law enforcement: Even as it places
    law-abiding U.S. importers and producers at a competitive
    disadvantage by making the United States market an easy
    target for illegal HFCs, it will help the illegal product to
    circulate unseen by U.S. law enforcement.
    I.
    HFCs are highly potent greenhouse gases with global
    warming potentials “that can be hundreds to thousands of times
    more potent than carbon dioxide.” 
    86 Fed. Reg. 55,116
    ,
    55,123/3 (Oct. 5, 2021). “[T]heir use is growing worldwide,”
    in part due to “the increasing use of refrigeration and air
    conditioning equipment globally.” 
    Id.
     The amount of HFCs in
    the global atmosphere is thus increasing at “accelerating rates.”
    
    Id.
     “[E]levated concentrations of [greenhouse gases] including
    HFCs have been warming the planet, leading to changes in the
    Earth’s climate,” such as “in the frequency and intensity of heat
    waves, precipitation, and extreme weather events.” 
    Id. at 55
    ,124/2.
    Recognizing that releases of these potent greenhouse gases
    are projected to continue accelerating rapidly, the United States
    joined with more than 140 countries to ratify the so-called
    Kigali Amendment to the Montreal Protocol on Substances that
    Deplete the Ozone Layer. The signatories to the 2016 Kigali
    Amendment committed to a “global phasedown of the
    production and consumption of HFCs.” 
    Id. at 55
    ,123/3-24/1;
    see 
    id. at 55
    ,139/1-2. If fully implemented, the Kigali
    3
    Amendment “is expected to avoid up to 0.5 °C of warming by
    2100.” 
    Id. at 55
    ,124/1.
    In keeping with that international commitment to phase
    down HFCs, Congress enacted the bipartisan American
    Innovation and Manufacturing (AIM) Act. Pub. L. No. 116-
    260, div. S, § 103, 
    134 Stat. 2255
    , 2255-71 (2020) (codified at
    
    42 U.S.C. § 7675
    ). Under the Act, HFC production and
    consumption in the United States must be phased down to 15
    percent of baseline levels by 2036. 
    42 U.S.C. § 7675
    (e)(2).
    The Act imposes those steep restrictions on HFC supply while
    other parties to the Kigali Amendment are also limiting the
    supply of HFCs in “ways that are similar.” 86 Fed. Reg. at
    55,139/1.
    Ensuring compliance with that HFC phasedown will be no
    small feat. As countries around the world tighten restrictions
    on HFCs, incentives to trade illegally are surging. In EPA’s
    experience—including during the United States’ participation
    in the global phasedown of ozone-depleting substances and in
    the early stages of the HFC phasedown elsewhere—declining
    allowances for lawful import and production of a substance
    tend to increase its illegal trade. See id. at 55,166/2-68/1,
    55,166/2 n.63. Indeed, observed rates of noncompliance with
    HFC quota systems have been dramatic. One study found that
    even those imports that were reported to European customs
    officials “exceeded the quota amount by 16 percent in 2019 and
    33 percent in 2020.” Id. at 55,167/1. In another study, 72
    percent of surveyed companies in Europe, where disposable
    cylinders are illegal, “had seen or been offered refrigerants in
    disposable cylinders.” Id. at 55,166/3. The United States faces
    similar pressures. Id. at 55,167/2. Without appropriate
    compliance measures to enable vigorous enforcement, illegal
    trade will likely swamp the congressionally mandated
    phasedown. Left unchecked, illicit trade in HFCs threatens to
    4
    “significantly harm the environment, the United States
    economy, and consumer and worker safety.” Id. at 55,168/1.
    In promulgating the phasedown rule mandated by the Act,
    EPA thus took a “multifaceted approach . . . to deter, identify,
    and penalize illegal activity.” Id. EPA adopted sensible
    compliance measures to ensure the HFC phasedown and “to
    create a level playing field for the regulated community.” Id.
    Two such compliance measures are at issue here: first, a
    prohibition on single-use cylinders for regulated HFCs and,
    second, a container-tracking system requiring QR codes to
    provide visibility into the import, sale, and distribution of
    HFCs.
    II.
    Two provisions of the AIM Act work in tandem to
    authorize EPA’s refillable-cylinder and QR-code regulations.
    First is subsection 7675(k)(1)(A), which empowers EPA to
    “promulgate such regulations as are necessary to carry out the
    functions of the Administrator” under the Act. 
    42 U.S.C. § 7675
    (k)(1)(A). The majority explains that “(k)(1)(A) is a
    source of procedural not substantive authority – it lets the
    agency pass rules to carry out powers granted by other
    provisions of the statute.” Maj. Op. 11. So far, so good. On
    this much the majority and I agree: Whenever the Act assigns
    to EPA a substantive responsibility or function, EPA may also
    promulgate rules “as necessary” to carry out that function.
    The second provision—and source of EPA’s substantive
    responsibility—is subsection 7675(e)(2)(B).     Recall that
    subsection (e)(2)(B), entitled “Compliance,” says that EPA
    “shall ensure” that annual HFC production or consumption
    “does not exceed” the congressionally mandated cap for any
    given year. 
    42 U.S.C. § 7675
    (e)(2)(B). On the meaning of that
    provision, the majority and I part ways. To be sure, the
    5
    majority starts off on the right foot: Subsection (e)(2)(B) does
    set out the production and consumption caps and provide the
    formula for calculating them. But, while it includes a formula,
    subsection (e)(2)(B) is not just a “math equation.” Maj. Op.
    12.
    In subsection (e)(2)(B), Congress called on EPA to make
    certain that the HFC phasedown is achieved. That duty flows
    from the plain text of the provision. The operative words are
    “shall ensure.” “The first sign that the statute impose[s] an
    obligation is its mandatory language: ‘shall.’” Me. Cmty.
    Health Options v. United States, 
    140 S. Ct. 1308
    , 1320 (2020).
    “[T]he word ‘shall’ usually connotes a requirement.” 
    Id.
    (quoting Kingdomware Techs., Inc. v. United States, 
    579 U.S. 162
    , 171 (2016)). The duty subsection (e)(2)(B) places on EPA
    is to “ensure”—that is, to guarantee—that annual HFC
    production or consumption “does not exceed” the
    congressionally mandated cap for any given year. 
    42 U.S.C. § 7675
    (e)(2)(B). In other words, as EPA put it, the agency has
    “the responsibility to ensure that the statutorily required
    phasedown occurs.” 86 Fed. Reg. at 55,172/3.
    Congress supplied another cue as to the intended meaning
    of subsection (e)(2)(B): its heading. See Merit Mgmt. Grp., LP
    v. FTI Consulting, Inc., 
    138 S. Ct. 883
    , 893 (2018). In
    subsection (e)(2)(B), Congress described EPA’s authority as
    one of “Compliance”—not just “Calculation.” That choice of
    heading underscores that Congress intended to impose on EPA
    a duty to guard against non-compliance with the
    congressionally mandated phasedown.
    As the majority recognizes, however, subsection (e)(2)(B)
    does not spell out in detail how the agency is to ensure the cap
    is met. Maj. Op. 13. For that, we return to EPA’s procedural
    authority found in subsection (k)(1)(A). Because one of the
    6
    Administrator’s functions under the Act is to “ensure”
    compliance with the phasedown, 
    42 U.S.C. § 7675
    (e)(2)(B),
    EPA may issue appropriate rules as necessary to do so, 
    id.
    § 7675(k)(1)(A). That is, Congress delegated to EPA the
    authority to promulgate reasonable compliance measures, so
    long as they are necessary to guaranteeing that the phasedown
    is met (and do not conflict with any other provision of the Act).
    The final rule under review is a run-of-the-mill exercise of
    EPA’s compliance responsibilities under the Act. EPA
    concluded that both the refillable-cylinder and QR-code
    requirements were “necessary” to “ensure” annual HFC
    production and consumption do not exceed the phasedown
    limits. See id. § 7675(e)(2)(B), (k)(1)(A). As EPA explained,
    “[a] program to control the production and import of HFCs is
    only achievable to the extent it can be enforced.” 86 Fed. Reg.
    at 55,175/1. Therefore, “[r]estrictions designed to deter and
    identify illegal imports . . . are a necessary component to such
    a program.” Id. (emphasis added).
    A refillable-cylinder requirement is necessary because the
    “visual differences” between disposable and refillable
    cylinders “allow Customs officials and law enforcement
    personnel to easily distinguish” between legally permitted
    refillable cylinders and disposable ones that “are favored for
    illicit trade.” Id. at 55,173/1. Indeed, refillable-cylinder
    requirements have a “proven track record of facilitating
    detection and interdiction of illegal HFCs.” Id. Several other
    jurisdictions, including the European Union, Canada,
    Australia, and India, have already adopted such requirements.
    Similarly, “a comprehensive container tracking system is
    needed” so as “[t]o help ensure the quantity of regulated
    substances produced or consumed in the United States does not
    exceed the Congressionally mandated cap.” Id. at 55,186/1.
    7
    The QR-code tracking system makes it easy to spot HFCs that
    do not enter the market legally. Id. at 55,183/3. Such a system
    is also “especially important for identifying illegal production
    [within the United States]—as that material will not have a
    check at the port like imports.” Id. at 55,185/3.
    Not only were both measures permissibly promulgated
    under the AIM Act, but they were also well within EPA’s
    expertise. For example, EPA has long regulated the containers
    and labeling for other substances it regulates, such as
    pesticides, see, e.g., 
    40 C.F.R. § 156.3
     et seq. (labeling
    requirements); 
    id.
     § 165.1 et seq. (container requirements), and
    underground storage tanks for biofuels, see id. § 280.10 et seq.
    And, in running other trading programs, EPA is familiar with
    the need for systems to track substances subject to statutory
    quantity controls. See, e.g., id. § 80.1425 et seq. (requiring
    renewable identification numbers, or RINs, to account for
    batches of qualifying renewable fuels). Furthermore, EPA has
    long partnered with other federal agencies, including U.S.
    Customs and Border Protection (CBP) and the Department of
    Justice, to help curb illicit trade in substances that it regulates.
    Since the 1990s, for instance, EPA has coordinated with CBP
    and other agencies to ensure the phaseout of ozone-depleting
    substances—an experience which informed EPA’s
    promulgation of the rule at issue here. See 86 Fed. Reg. at
    55,167/3.
    As the final rule well illustrates, EPA’s compliance
    function is vital to the statutory scheme. Ensuring compliance
    with a stringent new HFC phasedown is a daunting task, for
    which agency specialization and adaptability are paramount.
    Rather than confine EPA to any one tool, Congress left it to
    agency discretion to determine how best to root out non-
    compliant trade in HFCs. Given sophisticated efforts to evade
    HFC phasedowns elsewhere—as well as EPA’s own
    8
    experience combatting illicit trade in ozone-depleting
    substances—it made sense for Congress not to specify precise
    methods, but to charge EPA to adopt compliance measures as
    necessitated by the circumstances, and to adapt and improve
    them based on the lessons of experience. See id. at 55,166/2-
    68/1.
    The AIM Act is clear and robust on paper. But without the
    subsection (e)(2)(B) compliance function, it may prove flimsy
    in practice. As EPA explained, the steep domestic phasedown
    of HFCs will meet forceful and sophisticated efforts from
    around the globe to evade the HFC allowance system. See id.
    The court’s decision today to read out of the Act the limited but
    flexible authority to prevent such noncompliance leaves EPA
    with few and inadequate tools to ensure the HFC phasedown is
    achieved.
    III.
    The majority resists the plain meaning of subsection
    (e)(2)(B) by characterizing it as only “a formula setting the cap
    for each year of the phasedown.” Maj. Op. 12. That is a
    cramped reading of the language Congress used in subsection
    (e)(2)(B).
    For one, Congress’ use of the word “ensure”—which, as
    the majority agrees, means to make sure or to “guarantee,” Maj.
    Op. 13—is a perplexing one for a provision that my colleagues
    say describes only a calculation. If Congress wanted
    subsection (e)(2)(B) to provide EPA only the limited authority
    to calculate the production and consumption caps, it could
    easily have done so. Subsection (e) is littered with instructions
    for EPA to establish or calculate certain numerical values:
    Congress instructed that EPA “shall establish” production and
    consumption baselines for the phase-down of regulated
    substances, 
    42 U.S.C. § 7675
    (e)(1)(A); that each of those
    9
    baselines “is the quantity equal to the sum of” certain
    statutorily enumerated calculations, 
    id.
     § 7675(e)(1)(B), (C);
    and that, in calculating those baselines, “the Administrator
    shall use” certain exchange values provided in the statute, id.
    § 7675(e)(1)(D). Put otherwise, Congress knew how to
    prescribe a mere calculation. It did more than that in subsection
    (e)(2)(B).
    Nor should we read much into the fact that the Act at times
    gives EPA “detailed instructions” regarding other agency
    responsibilities. Maj. Op. 14. The expressio unius canon on
    which the majority relies is “an especially feeble helper in the
    administrative setting, where Congress is presumed to have left
    to reasonable agency discretion questions that it has not
    directly resolved.” Cheney R.R. Co. v. ICC, 
    902 F.2d 66
    , 69
    (D.C. Cir. 1990). In the administrative context, “we have
    consistently recognized that a congressional mandate in one
    section and silence in another often ‘suggests not a prohibition
    but simply a decision not to mandate any solution in the second
    context, i.e., to leave the question to agency discretion.’”
    Catawba Cnty., N.C. v. EPA, 
    571 F.3d 20
    , 36 (D.C. Cir. 2009)
    (quoting Cheney R.R. Co., 902 F.2d at 69).
    The majority’s reliance on the expressio unius canon is
    doubly irksome, however, because we normally “do not read
    the enumeration of one case to exclude another unless it is fair
    to suppose that Congress considered the unnamed possibility
    and meant to say no to it.” Barnhart v. Peabody Coal Co., 
    537 U.S. 149
    , 168 (2003). To read the statute as the majority does,
    we would have to “be confident that a normal draftsman when
    he expressed ‘the one thing’”—for example, the creation of an
    allowance-allocation-and-trading program—“would have
    likely considered the alternatives that are arguably
    precluded”—that is, refillable-cylinder and QR-code
    requirements—and by not mentioning them meant to put them
    10
    off limits. Shook v. D.C. Fin. Resp. & Mgmt. Assistance Auth.,
    
    132 F.3d 775
    , 782 (D.C. Cir. 1998). But neither the majority
    nor the trade associations have provided any reason to think
    that Congress considered and rejected either a refillable-
    cylinder requirement or container-tracking system.
    Rather, recognizing that it could not foresee every way in
    which regulated entities might evade the HFC phasedown,
    Congress in subsection (e)(2)(B) stated EPA’s compliance
    duties in general terms so as “‘to confer the flexibility
    necessary’ for [EPA] to address yet unknown threats” to the
    HFC phasedown. Corbett v. TSA, 
    19 F.4th 478
    , 488 (D.C. Cir.
    2021) (quoting Massachusetts v. EPA, 
    549 U.S. 497
    , 532
    (2007)). To the extent EPA’s compliance authority might be
    viewed as “broad,” Maj. Op. 14, that reflects Congress’
    deliberate choice to leave specific compliance measures to
    EPA’s discretion. “Congress knows to speak in plain terms
    when it wishes to circumscribe, and in capacious terms when it
    wishes to enlarge, agency discretion.” City of Arlington v.
    FCC, 
    569 U.S. 290
    , 296 (2013).
    Finally, it bears emphasis that the compliance authority
    granted and exercised here is not, relatively speaking,
    particularly broad. My colleagues’ conclusion that the
    authority EPA claims under subsection (e)(2)(B) is somehow
    disproportionate to the terms in which Congress conferred it,
    Maj. Op. 13-15, is badly misplaced. The modest regulatory
    measures EPA promulgated are a far cry from the kinds of
    sweeping or implausible measures that have triggered extra
    skepticism from the Supreme Court—whether that scrutiny
    takes the form the trade associations demand, see Association
    Reply Br. 11-13 (citing West Virginia v. United States, 
    142 S. Ct. 2587 (2022)
    ), or the majority undertakes, see Maj. Op. 14-
    15 (citing Whitman v. Am. Trucking Ass’ns, 
    531 U.S. 457
    (2001)). For one thing, EPA acted here within the limited
    11
    ambit of a recent, pollutant-specific statute to deploy familiar
    tools to help effectuate a defined phasedown. For another, the
    ostensible “magnitude” of the compliance costs on industry is
    overstated. The prohibition on single-use cylinders is projected
    to cost a mere $22 million annually on average, and the QR-
    code tracking system would cost even less. 86 Fed. Reg. at
    55,174/1; U.S. Env’t Prot. Agency, EPA-HQ-OAR-2021-
    0044-0227-02, Regulatory Impact Analysis for Phasing Down
    Production and Consumption of Hydrofluorocarbons (HFCs)
    69 (2021) (J.A. 720). Those costs would seem to be a mere
    drop in the bucket for a multi-billion-dollar regulated industry.
    And they are no reason for enhanced judicial scrutiny in the
    face of the far greater health and welfare costs likely to flow
    from circumventing the phasedown. See 86 Fed. Reg. at
    55,119/1-2 & tbl.1, 55,197 tbl.8 (estimating the rule’s
    annualized net benefits at more than $14 billion).
    In any case, the American Trucking decision relied on by
    the majority “stands for the rather unremarkable proposition
    that sometimes statutory silence, when viewed in context, is
    best interpreted as limiting agency discretion.” Entergy
    Corp. v. Riverkeeper, Inc., 
    556 U.S. 208
    , 223 (2009). But, as
    we have already seen, the statutory text and context here point
    in the other direction: Congress assigned to EPA the function
    of “ensur[ing]” nationwide “[c]ompliance” with the HFC
    phasedown schedule and empowered the agency to promulgate
    rules “as are necessary to carry out” that function. 
    42 U.S.C. § 7675
    (e)(2)(B), (k)(1)(A). In so doing, Congress left the
    development of specific compliance measures up to EPA’s
    informed discretion. EPA’s entirely unsurprising choice to set
    up a standardized system for transporting HFCs in refillable
    cylinders labeled with trackable QR-codes falls comfortably
    within that discretion.
    12
    ***
    In short, EPA validly exercised its authority under the
    AIM Act to ban non-refillable cylinders and adopt a container-
    tracking system. Because today’s decision understates and
    undercuts EPA’s statutorily imposed authority and duty to
    ensure compliance with the HFC phasedown, I respectfully
    dissent from Section II.C of the majority opinion.