Rinnai America Corporation v. South Coast Air Quality Management District

FOR PUBLICATION UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT No. 25-5129 RINNAI AMERICA CORPORATION; NORITZ D.C. No. AMERICA CORPORATION; 2:24-cv-10482- NATIONAL ASSOCIATION OF PA-PD HOME BUILDERS; CALIFORNIA STATE PIPE TRADES COUNCIL; CALIFORNIA MANUFACTURERS OPINION & TECHNOLOGY ASSOCIATION; CALIFORNIA RESTAURANT ASSOCIATION; RESTAURANT LAW CENTER; CALIFORNIANS FOR HOMEOWNERSHIP, INC.; CALIFORNIA HOTEL & LODGING ASSOCIATION; CALIFORNIA APARTMENT ASSOCIATION; PLUMBING- HEATING-COOLING CONTRACTORS OF CALIFORNIA, Plaintiffs - Appellants, v. SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT, Defendant - Appellee, 2 RINNAI AMERICA CORP. V. SCAQMD PEOPLE'S COLLECTIVE FOR ENVIRONMENTAL JUSTICE; SIERRA CLUB; INDUSTRIOUS LABS, Intervenor-Defendants - Appellees. Appeal from the United States District Court for the Central District of California Percy Anderson, District Judge, Presiding Argued and Submitted February 5, 2026 Pasadena, California Filed July 2, 2026 Before: Kenneth K. Lee, Lucy H. Koh, and Ana de Alba, Circuit Judges. Opinion by Judge Koh; Dissent by Judge Lee  RINNAI AMERICA CORP. V. SCAQMD 3 SUMMARY * Environmental Law Affirming the district court’s grant of summary judgment to South Coast Air Quality Management District (“District”), the agency responsible for air pollution control in the South Coast Air Basin (“Basin”), the panel held that the Energy Policy and Conservation Act (“EPCA”) does not preempt the District’s amended Rule 1146.2, which seeks to achieve compliance with federal ozone standards under the Clean Air Act (“CAA”). The Basin has the worst smog (or ground-level ozone) in the country and is in “extreme” nonattainment with all federal ozone standards and thus risks losing its federal highway funding and being assessed substantial penalties. Since its creation in the 1970s, the District has implemented rules regulating nitrous oxide emissions from appliances and other stationary sources in an effort to bring itself into compliance with the federal air quality standards. Numerous other jurisdictions, including Texas and Utah, have adopted similar nitrous oxide emissions standards for appliances, and the EPA has routinely approved these standards. In 2022, the District determined that widespread adoption of a zero emissions standard across all stationary sources, including appliances, was the only viable way to bring the Basin into compliance with federal ozone standards. As a result, the District passed Rule 1146.2, which over the next decade phases in zero nitrous oxide emission * This summary constitutes no part of the opinion of the court. It has been prepared by court staff for the convenience of the reader. 4 RINNAI AMERICA CORP. V. SCAQMD standards on certain appliances. The Bay Area enacted similar appliance standards in March 2023, and to date, no challenge to those standards has been filed. The panel held that the District’s effort to comply with the federal air quality standards under the CAA was not preempted by EPCA, which was designed instead to counteract the patchwork of energy efficiency standards for appliances that existed in the 1980s. The panel held that nothing in the text, structure, or history of EPCA suggested that Congress intended to interfere with states’ ability to use these well-established methods to achieve compliance with federal air quality standards under the CAA. The plaintiffs failed to identify any language in EPCA indicating Congress’s intent to preempt CAA emissions regulations. The panel held that California Restaurant Ass’n v. City of Berkeley (“CRA”), 89 F.4th 1094 (9th Cir. 2024), explicitly declined to address whether EPCA preempts state regulations enacted pursuant to another federal statute and repeatedly acknowledged that it was a “very narrow” decision. Moreover, the named plaintiff California Restaurant Association, which is also a plaintiff in the instant case, explicitly conceded in CRA that “regulations of nitrogen oxide emissions” do not “concern energy use” and are not “barred by [CRA’s] interpretation of the EPCA.” The panel further held that the plaintiffs’ facial challenge failed because the District’s Rule 1146.2 regulates emissions from process heaters, which are not among the list of covered products under EPCA and for which the Department of Energy has not issued any federal standards. Thus, the plaintiffs failed to show that the Rule is unconstitutional in every application.  RINNAI AMERICA CORP. V. SCAQMD 5 Dissenting, Judge Lee wrote that California Restaurant Ass’n v. City of Berkeley controls this case. Just like in California Restaurant Ass’n v. City of Berkeley, EPCA preempts the District’s rule on nitrous oxide emissions because it similarly regulates “energy use” of a “covered product.” COUNSEL Brian C. Baran (argued), Reichman Jorgensen Lehman & Feldberg LLP, Washington, D.C.; Courtland L. Reichman, Reichman Jorgensen Lehman & Feldberg LLP, Redwood Shores, California; Sarah O. Jorgensen, Reichman Jorgensen Lehman & Feldberg LLP, Atlanta, Georgia; Sean M. Kneafsey, Kneafsey Firm, Los Angeles, California; Luke Dowling and John J. Davis Jr., McCracken Stemerman & Holsberry LLP, Oakland, California; Angelo I. Amador, Restaurant Law Center, Washington, D.C.; Matthew P. Gelfand, Californians for Homeownership Inc., Sacramento, California; for Plaintiffs-Appellants. Matthew D. Zinn (argued), Ryan K. Gallagher, and Lauren M. Tarpey, Shute Mihaly & Weinberger LLP, San Francisco, California; Barbara Baird, Chief Deputy District Counsel; Bayron T. Gilchrist, General Counsel; South Coast Air Quality Management District, Diamond Bar, California; for Defendant-Appellee. Candice L. Youngblood and Adriano L. Martinez, Earthjustice, Los Angeles, California; James A. Dennison, Sierra Club, Boulder, Colorado; Sean H. Donahue, Donahue Goldberg & Herzog, Washington, D.C.; for Intervenor- Defendants-Appellees. 6 RINNAI AMERICA CORP. V. SCAQMD Edward P. Sangster, Ankur K. Tohan and David Wang, K&L Gates LLP, San Francisco, California, for Amicus Curiae Navien, Inc.. J. Mark Little, Baker Botts LLP, Houston, Texas; Daniel Rankin, Baker Botts LLP, Austin, Texas; Michael Murray, American Gas Association, Washington, D.C.; for Amicus Curiae American Gas Association. Cara A. Horowitz, Brennon K. Mendez, and Tiffany Deguzman, Frank G. Wells Environmental Law Clinic, UCLA School of Law, Los Angeles, California, for Amicus Curiae Northeast States for Coordinated Air Use Management. Daniel N. Carpenter-Gold, Esther Agbaje, and Mia M. Hammersley, Public Health Law Center, St. Paul, Minnesota, for Amicus Curiae Public Health Law Center. Jonathan A. Wiener and Benjamin P. Lempert, Deputy Attorneys General; Myung J. Park, Supervising Deputy Attorney General; Annadel A. Almendras, Senior Assistant Attorney General; Rob Bonta, California Attorney General; Office of the California Attorney General, San Francisco, California; for Amicus Curiae California Air Resources Board.  RINNAI AMERICA CORP. V. SCAQMD 7 OPINION KOH, Circuit Judge: Defendant-Appellee South Coast Air Quality Management District (the “District”) is the agency responsible for air pollution control in the South Coast Air Basin (the “Basin”), a region that includes large portions of Los Angeles, Orange, Riverside, and San Bernardino counties. The Basin has the worst smog, or ground-level ozone, in the country and is in “extreme” nonattainment with all federal ozone standards under the Clean Air Act (“CAA”), 42 U.S.C. § 7401 et seq. On June 7, 2024, after determining that widespread adoption of zero emissions technology across all stationary sources was the only viable way to bring the Basin into compliance with federal ozone standards, the District adopted amendments to Rule 1146.2 (“Rule 1146.2” or the “Rule”). As amended, Rule 1146.2 phases in prohibitions on the manufacture, sale, or installation of gas-fired water heaters, boilers, and process heaters that emit more than zero nitrous oxides (“NOx”). Plaintiffs-Appellants, who include manufacturers of gas appliances and various industry groups, filed suit challenging Rule 1146.2 on the grounds that it is preempted by the Energy Policy and Conservation Act (“EPCA”), 42 U.S.C. § 6201 et seq. The district court granted summary judgment in favor of the District. We affirm. 8 RINNAI AMERICA CORP. V. SCAQMD I. BACKGROUND AND PROCEDURAL HISTORY A. Regulatory Background 1. Clean Air Act The regulation of air pollution has historically been a matter of state authority. See Exxon Mobil Corp. v. E.P.A., 217 F.3d 1246, 1255 (9th Cir. 2000) (“Air pollution prevention falls under the broad police powers of the states, which include the power to protect the health of citizens in the state.”). Beginning in the 1950s, however, Congress began enacting a series of laws gradually increasing federal involvement in the prevention of air pollution. These early federal efforts were focused primarily on funding research and providing technical and financial assistance to the states. See Train v. Nat. Res. Def. Council, Inc., 421 U.S. 60, 63-64 (1975) (discussing history of federal involvement). In 1963, Congress passed the first iteration of the CAA, the Clean Air Act of 1963, Pub. L. No. 88-206, 77 Stat. 392, which, in addition to expanding federal research efforts and funding to the states, authorized federal authorities “to intervene directly to abate interstate pollution in limited circumstances.” Train, 421 U.S. at 64. The Air Quality Act of 1967, Pub. L. No. 90-148, 81 Stat. 485, marked the beginning of a shift towards greater federal involvement in regulating air pollution. The 1967 Act required the Secretary of the Department of Health, Education and Welfare to promulgate air quality criteria for various regions across the United States. See Air Quality Act of 1967 § 107(b). However, the 1967 Act “reiterated the premise . . . ‘that the prevention and control of air pollution at its source is the primary responsibility of States and local governments.’” Train, 421 U.S. at 64 (quoting Air Quality Act of 1967 § 101(a)(3)). Thus, the states “generally retained  RINNAI AMERICA CORP. V. SCAQMD 9 wide latitude to determine both the air quality standards which they would meet and the period of time in which they would do so.” Id. The Air Quality Act of 1967 ultimately proved ineffective at addressing the growing problem of air pollution, in part due to the lack of sufficient federal enforcement mechanisms. See id. In response, Congress passed the Clean Air Amendments of 1970, Pub. L. No. 91- 604, 84 Stat. 1676, which created the modern federal air pollution control program. See Train, 421 U.S. at 64. The 1970 amendments to the CAA “sharply increased federal authority and responsibility in the continuing effort to combat air pollution,” while at the same time preserving the principle that “the primary responsibility for assuring air quality” belonged with the states. Id. (quoting Clean Air Amendments of 1970 § 107(a)). The CAA aims to “promote reasonable Federal, State, and local governmental actions . . . for pollution prevention.” 42 U.S.C. § 7401(c). 1 To achieve this goal, the CAA outlines a framework of “federal-state collaboration.” Ohio v. E.P.A., 603 U.S. 279, 283 (2024) (quoting EME Homer City Generation, L.P. v. E.P.A., 795 F.3d 118, 124 (D.C. Cir. 2015)). The best known example of this federal-state framework is the CAA’s provisions regarding National Ambient Air Quality Standards (“NAAQS”). Under the CAA, the U.S. Environmental Protection Agency (“EPA”) is required to set standards for certain air pollutants as necessary to protect the public health. § 7409(a)(1), (b)(1). The EPA must also identify areas that have not attained these federal standards (so-called “nonattainment” areas). 1 Hereinafter, all references to “§” refer to Title 42 of the United States Code, unless otherwise indicated. 10 RINNAI AMERICA CORP. V. SCAQMD § 7407(d). States are then required to submit a State Implementation Plan (“SIP”) for the “implementation, maintenance, and enforcement” of the NAAQS in their jurisdictions within a specified time period. § 7410(a)(1). In crafting SIPs, states bear the “initial and primary responsibility for deciding what emissions reductions will be required from which sources.” Whitman v. Am. Trucking Ass’ns, 531 U.S. 457, 470 (2001); see also § 7401(a)(3) (stating that “air pollution prevention (that is, the reduction or elimination, through any measures, of the amount of pollutants produced or created at the source) and air pollution control at its source is the primary responsibility of States and local governments”). Although the CAA gives states latitude in deciding how best to curb emissions, it requires that nonattainment areas implement “all reasonably available control measures as expeditiously as practicable” or face certain penalties. §§ 7502(c)(1), 7413. When prior versions of the CAA proved ineffective at adequately controlling pollutants, 2 Congress amended the CAA in 1990, Pub. L. No. 101-549, 104 Stat. 2399, to provide more comprehensive regulation of specific pollutants, including ozone and particulate matter, and to increase the consequences for nonattainment. See S. Coast Air Quality Mgmt. Dist. v. E.P.A., 472 F.3d 882, 887- 88 (D.C. Cir. 2006) (discussing 1990 amendments). The 1990 amendments created a new classification scheme for nonattainment areas—ranked from “marginal” to “extreme,” § 7511(a)(1)—and strengthened enforcement measures 2 For example, in response to “widespread failure by the states to attain NAAQS,” Congress amended the Clean Air Act in 1977 to allow the states more time to attain NAAQS. Coal. for Clean Air v. S. Cal. Edison Co., 971 F.2d 219, 222 (9th Cir. 1992).  RINNAI AMERICA CORP. V. SCAQMD 11 against the worst nonattainment areas, § 7511d. The potential penalties faced by “extreme” nonattainment areas include the imposition of large annual fees for every ton of pollutant emitted over the baseline and the loss of federal highway funding. §§ 7509(b), 7413, 7511d. 2. Energy Policy and Conservation Act In 1975, five years after the passage of the Clean Air Amendments of 1970, Congress passed EPCA. Enacted in the aftermath of the oil embargo imposed against the United States by certain countries in 1973 and 1974, “EPCA was designed, in part, to reduce the United States’ ‘domestic energy consumption through the operation of specific voluntary and mandatory energy conservation programs.’” Air Conditioning & Refrigeration Inst. v. Energy Res. Conservation & Dev. Comm’n, 410 F.3d 492, 498-99 (9th Cir. 2005) (quoting S. Rep. No. 94-516, at 117 (1975)). When first enacted, EPCA was concerned primarily with labeling on consumer appliances. Because “Congress believed that better informed consumers and voluntary efforts by manufacturers would make energy efficiency standards unnecessary,” EPCA required that manufacturers label appliances with measures of energy efficiency and energy use and “provided that the Secretary of the Federal Energy Administration should utilize energy efficiency standards if the labeling program proved ineffective.” Id. at 499. In keeping with this focus on labeling, EPCA contained a provision expressly preempting state regulations insofar as “they were ‘other than’ the applicable federal rules for testing and labeling.” Id. (quoting EPCA, Pub. L. No. 94- 163, § 327(a)(1), 89 Stat. 871, 927 (1975)). In 1978, Congress amended EPCA to improve the procedures for establishing national standards and to “ensure 12 RINNAI AMERICA CORP. V. SCAQMD that efficiency improvements will be made expeditiously.” Nat. Res. Def. Council, Inc. v. Herrington, 768 F.2d 1355, 1362 (D.C. Cir. 1985) (quoting H.R. Rep. No. 496, pt. 4 (1977)). The amended version of EPCA created “a nationwide conservation program for appliances and required the [Department of Energy (“DOE”)] to prescribe minimum energy efficiency standards for thirteen covered products.” Air Conditioning, 410 F.3d at 499. The DOE, however, declined to promulgate any federal standards and instead adopted a general policy of granting preemption waivers to states. Id. This resulted in a patchwork of different minimum energy efficiency standards for the same appliances across the states, which complicated appliance manufacturers’ “design, production and marketing plans.” Id. at 500 (quoting S. Rep. No. 100-6, at 4 (1987)). In response, manufacturer trade associations negotiated with the Natural Resources Defense Council to establish uniform national standards, which Congress later enacted into law through the passage of the National Appliance Energy Conservation Act of 1987. Id. at 499-500. This 1987 law amended EPCA and broadened its preemption provision “to counteract the systems of separate state appliance standards that had emerged.” Id. at 500. EPCA’s current preemption provision 3—the one at issue in this case—states that, subject to various exceptions, “effective on the effective date of an energy conservation standard established in or prescribed under section 6295 of this title for any covered product, no State regulation concerning the energy efficiency, energy use, or water use of such covered product shall be effective with respect to 3 The current version of this provision reflects minor amendments made since 1987, none of which are relevant to this appeal.  RINNAI AMERICA CORP. V. SCAQMD 13 such product.” § 6297(c). EPCA defines “energy use” as “the quantity of energy directly consumed by a consumer product at point of use, determined in accordance with test procedures under section 6293 of this title,” § 6291(4), and defines “energy efficiency” as “the ratio of the useful output of services from a consumer product to the energy use of such product, determined in accordance with test procedures under section 6293 of this title,” § 6291(5). “Energy,” in turn, is defined as “electricity, or fossil fuels.” § 6291(3). “Covered products” include consumer products such as refrigerators, air conditioners, water heaters, furnaces, and kitchen ovens. §§ 6291(1), 6292. B. Factual Background The South Coast Air Quality Management District is the agency responsible for air pollution control for the South Coast Air Basin (the “Basin”), an area that includes Orange County and the urban portions of Los Angeles, Riverside, and San Bernardino counties. More than 17 million people live in the Basin. The Basin has the worst smog, or ground- level ozone, in the country and is in “extreme” nonattainment for all federal ozone pollution standards. See 40 C.F.R. § 81.305. Ground-level ozone forms when volatile organic compounds interact with NOx in the atmosphere in the presence of sunlight. Exposure to high levels of ozone carries significant health risks, including asthma, chronic bronchitis, emphysema, increased susceptibility to respiratory infection, and premature death. In 2020, nine of the country’s top ten locations most frequently exceeding the 2015 federal 8 hour ozone standard 4—as well as the location 4 In 2015, the EPA set the NAAQS for ozone at a daily maximum 8 hour average of 70 parts per billion (“2015 federal 8 hour ozone standard”). See 40 C.F.R. § 50.19. 14 RINNAI AMERICA CORP. V. SCAQMD with the highest number of days over the 8 hour ozone standard and the location with the single highest recorded maximum 8 hour average ozone concentration—were all located within the Basin. Recognizing that the Basin faced “the most critical air pollution problem in the nation,” the California legislature established the District in 1976 to address the issue. 1976 Cal. Stat. 891, 893. Under California law, the District is required to adopt and amend air quality management plans to achieve and maintain federal and state ambient air quality standards. See Cal. Health & Safety Code § 40460(a). These plans are submitted to the EPA and serve as the federally required SIP under the CAA. See id. § 40460(d). Since its creation in the 1970s, the District has implemented rules regulating NOx emissions from appliances and other stationary sources. The District adopted the first iteration of the challenged rule, Rule 1146.2, in 1998. Initially, Rule 1146.2 limited NOx emissions to 30 parts per million (“ppm”) on most covered appliances. The Rule was subsequently amended in 2005, 2006, and 2018 to cover a greater number of appliances and to further limit emissions to 20 ppm for most covered appliances. Despite these and other efforts to reduce emissions, the Basin has been unable to attain compliance with federal ozone standards. The District is required to bring the Basin into attainment of the 2015 federal 8 hour ozone standard by the year 2038. To do so, the District must achieve a reduction in NOx emissions of 124 tons per day, which equates to a 67 percent reduction beyond the reductions projected by the previously adopted rules and an 83 percent reduction below current levels.  RINNAI AMERICA CORP. V. SCAQMD 15 In December 2022, the District adopted the most recent amendment to the District’s air quality management plan (the “2022 Plan”). The 2022 Plan found that “there is no viable pathway to achieve the needed reductions without widespread adoption of zero emissions (ZE) technology across all . . . stationary sources, large and small.” To address this determination, the 2022 Plan called for the District to require zero NOx emissions from commercial water heaters. According to the District’s estimates, emissions from appliances account for nearly 20 percent of the emissions from the residential and commercial combustion stationary sources the District regulates. The District began rulemaking proceedings to implement the 2022 Plan in April 2023. On June 7, 2024, following fourteen months of deliberation, the District adopted amendments to Rule 1146.2. The stated purpose of the Rule is “to reduce Oxides of Nitrogen (NOx) emissions from Water Heaters, Boilers, and Process Heaters fired with, or designed to be fired with, natural gas.” The Rule prohibits the manufacture, sale, or installation of large water heaters, small boilers, and process heaters that emit more than zero NOx. The Rule’s implementation is subject to staggered deadlines based on the type of unit and whether it is installed in a new or existing building. The first compliance deadline, which applies to a limited subset of units installed in new buildings, took effect January 1, 2026. Once fully implemented, the Rule will eliminate nearly 10 percent of emissions within the Basin. C. Procedural Background On December 5, 2024, Plaintiffs filed a lawsuit challenging the Rule in the Central District of California. In the operative first amended complaint, Plaintiffs asserted a 16 RINNAI AMERICA CORP. V. SCAQMD single cause of action alleging that the Rule is preempted by EPCA. Plaintiffs brought this claim as a facial challenge and asserted that “[t]here is no set of circumstances under which the rule can be valid under federal law.” Plaintiffs requested that the court issue a “declaratory judgment . . . that the District’s Rule 1146.2 is preempted by federal law . . . and is therefore void and unenforceable,” as well as “a permanent injunction enjoining the District from enforcing or attempting to enforce Rule 1146.2’s zero-NOx emissions limits.” On April 14, 2025, Plaintiffs moved for summary judgment. The District filed a cross-motion on May 12, 2025. On July 18, 2025, the district court denied Plaintiffs’ motion, granted the District’s motion, and entered judgment in favor of the District. On July 22, 2025, the district court made modest modifications to its summary judgment order. As set forth in its amended order, the district court held that the Rule was not preempted because it “does not concern the energy use of appliances under the EPCA.” The district court explained that “the Rule regulates appliances’ NOx emissions in order to address air pollution issues and the health risks associated with the combustion of natural gas,” and “does not implicate any of the issues the EPCA was intended to address.” On August 27, 2025, Plaintiffs moved before the district court for an injunction pending appeal. The district court denied the motion on September 29, 2025. On October 6, 2025, Plaintiffs filed a motion for an injunction pending appeal before this Court, which we denied on December 22, 2025.  RINNAI AMERICA CORP. V. SCAQMD 17 II. STANDARD OF REVIEW We “review de novo the district court’s order granting summary judgment on preemption grounds.” Am. Apparel & Footwear Ass’n, Inc. v. Baden, 107 F.4th 934, 938 (9th Cir. 2024). Where, as here, a statute contains an express preemption clause, we look to the “text, framework, and historical context” of the statute to discern Congress’s intent. R.J. Reynolds Tobacco Co. v. County of Los Angeles, 29 F.4th 542, 552 (9th Cir. 2022); see also Dan’s City Used Cars, Inc. v. Pelkey, 569 U.S. 251, 260 (2013) (“We focus first on the statutory language, which necessarily contains the best evidence of Congress’ pre-emptive intent.” (citation modified)). Although we begin with the wording of the preemption clause, we “must also consider the statute as a whole to determine whether the local [regulation] actually conflicts with the overall federal regulatory scheme.” R.J. Reynolds, 29 F.4th at 553 (internal quotation marks and citation omitted). III. DISCUSSION The question presented in this appeal is whether EPCA preempts the District’s efforts to comply with its obligations under the CAA by enacting a zero NOx emissions standard for appliances. We hold that it does not. Under the CAA, states are required to take “all reasonably available control measures” to reduce emissions from existing sources. § 7502(c)(1). Pursuant to the CAA, the District and numerous other states and local regulators have long regulated appliance emissions, and the EPA has routinely approved such regulations. Nothing in the text, structure, or history of EPCA suggests that Congress intended to interfere with states’ ability to use these well-established methods to 18 RINNAI AMERICA CORP. V. SCAQMD achieve compliance with federal air quality standards under the CAA. Plaintiffs’ arguments to the contrary rely exclusively on our decision in California Restaurant Association v. City of Berkeley, 89 F.4th 1094 (9th Cir. 2024) [hereinafter CRA]. But as explained below, Plaintiffs read CRA far too broadly. Contrary to Plaintiffs’ assertions, our “very narrow” decision in that case did not consider the issue now before us: whether EPCA preempts state regulations enacted pursuant to another federal statute, like the CAA. Id. at 1106. Finally, even if we were to accept Plaintiffs’ interpretation of the scope of EPCA’s preemption provision, their facial challenge nonetheless fails. Plaintiffs cannot show that the Rule is unconstitutional in every application because the Rule regulates emissions from process heaters, which are not among the list of covered products under EPCA and for which the DOE has not issued any federal standards. For each of these reasons, addressed in turn below, we affirm the district court’s grant of summary judgment in favor of the District. A. EPCA’s Preemptive Scope Does Not Cover State Appliance Emissions Standards Enacted Pursuant to the CAA EPCA’s preemption provision states, in relevant part, that “effective on the effective date of an energy conservation standard established in or prescribed under section 6295 of this title for any covered product, no State regulation concerning the energy efficiency, energy use, or water use of such covered product shall be effective with respect to such product.” § 6297(c). “Energy use,” in  RINNAI AMERICA CORP. V. SCAQMD 19 turn, is defined as “the quantity of energy directly consumed by a consumer product at point of use, determined in accordance with test procedures under section 6293 of this title.” § 6291(4). As Plaintiffs concede, the text of EPCA contains no mention of emissions regulations. Plaintiffs nonetheless contend that EPCA’s preemption provision must be construed as prohibiting state and local regulators like the District from adopting zero NOx emissions standards consistent with the CAA. We find no support for that view in the text, framework, or history of EPCA. Enacted 5 years after the passage of the Clean Air Amendments of 1970, EPCA was initially designed to establish energy usage labeling requirements on appliances in response to the oil crisis of the 1970s. EPCA was then expanded in 1978 to create “a nationwide conservation program for appliances” and to require the DOE to establish “minimum energy efficiency standards for . . . covered products.” Air Conditioning, 410 F.3d at 499. The DOE, however, failed to do so and instead adopted a general policy of granting preemption waivers to states, which led to a patchwork of different state efficiency standards for the same appliances. Id. at 500. Congress responded by amending EPCA again in 1987 and broadening its preemption provision “to counteract the systems of separate state appliance standards that had emerged.” Id. The history of EPCA thus makes clear that Congress was concerned with the establishment of uniform conservation standards to remedy the patchwork of different state standards that existed under the previous regime. This focus is reflected in the text of EPCA’s preemption provision. That provision provides that once the DOE establishes a national 20 RINNAI AMERICA CORP. V. SCAQMD energy conservation standard for a covered product, state regulations concerning the energy use or energy efficiency of that product are preempted. § 6297(c). The exemptions to EPCA preemption further underscore this focus. The enumerated list of exemptions includes certain building codes, state procurement standards that are more stringent than federal energy conservation standards, and waivers “to meet unusual and compelling State or local energy or water interests.” § 6297(d)-(f). Each exemption relates to the energy efficiency and energy use of covered products. Notably absent from the text and legislative history of EPCA is any mention of appliance emissions standards. Indeed, although EPCA grants the DOE the authority to set energy conservation standards for appliances, § 6295, nothing in that grant of authority suggests that the DOE also possesses the authority to dictate state emissions standards. 5 That authority instead falls squarely within the framework of “federal-state collaboration” established by the CAA under the purview of the EPA. Ohio, 603 U.S. at 283; see § 7409(b)(1). As the U.S. Supreme Court has stated in an analogous context, the EPA’s statutory duty to protect the public’s health and welfare is “wholly independent” of another agency’s “mandate to promote energy efficiency.” Massachusetts v. E.P.A., 549 U.S. 497, 531-32 (2007) (rejecting the EPA’s argument that it lacked the authority to regulate greenhouse gas emissions from motor vehicles “because doing so would require it to tighten mileage 5 In relevant part, EPCA defines an “energy conservation standard” as “a performance standard which prescribes a minimum level of energy efficiency or a maximum quantity of energy use . . . for a covered product.” 42 U.S.C. § 6291(6).  RINNAI AMERICA CORP. V. SCAQMD 21 standards, a job (according to EPA) that Congress has assigned to [the Department of Transportation]”). Under the CAA, the EPA is required to set standards for air pollutants as necessary to protect the public health, see § 7409(a)(1), and states are required to take “all reasonably available control measures as expeditiously as practicable” to achieve compliance with those standards, including by reducing “emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of reasonably available control technology,” § 7502(c)(1). States that do not comply with these obligations face substantial penalties. Areas like the Basin, for example, that remain in “extreme” nonattainment with federal standards may be fined large annual fees for every ton of pollutant emitted over the baseline and may lose their federal highway funding. §§ 7509(b), 7413, 7511d. For decades, state and local regulators have utilized appliance emissions regulations as an important tool to help achieve compliance with the NAAQS. The District is one example. Since its inception in the 1970s, the District has regulated emissions from appliances like furnaces and water heaters. The District enacted the first iteration of Rule 1146.2 in 1998 and has subsequently amended the Rule several times to further restrict appliance emissions. These regulations are a critical part of the District’s pollution control efforts, as emissions from appliances account for almost 20 percent of all emissions from the stationary sources the District regulates. Indeed, the District’s 2022 Plan found that widespread adoption of a zero emissions standard across all stationary sources, including appliances, was the only viable way to bring the Basin into compliance with federal ozone standards. In other words, the District has 22 RINNAI AMERICA CORP. V. SCAQMD determined that it cannot comply with the CAA unless it enacts zero emissions standards like Rule 1146.2. 6 The District is not the only local regulatory agency that has relied on appliance emissions regulations. Amici identify 35 other jurisdictions ranging from Texas to Utah to Washington that have adopted similar low, ultra-low, and zero NOx emissions standards for appliances. Moreover, the Bay Area enacted zero NOx emissions standards for commercial water heaters and furnaces in March 2023, and yet to date, over three years later, no challenge to those standards has been filed. Over 60 other cities and counties in California, as well as states such as Colorado and Maryland, are likewise considering policies for zero emissions appliances. Critically, the federal government has not sought to prevent states from enacting these appliance emissions regulations but instead has supported the states’ efforts. The EPA has approved appliance emissions standards submitted by local regulators, including the District, in State Implementation Plans since at least 1986. See, e.g., 51 Fed. Reg. 600, 602 (Jan. 7, 1986) (approving the Bay Area Air Quality Management District’s NOx emissions standards for 6 Plaintiffs agree. Their reply brief states, “Plaintiffs do not doubt that Congress has put the District between a rock and a hard place by requiring it to meet ambitious air quality targets while denying it control over major emission sources.” Nonetheless, the dissent engages in speculation without any basis in the record that “California and the District could reduce NOx in countless ways beyond the rule at issue here.” Dissent at 41 n.4. Even Plaintiffs do not engage in such speculation. We note that the District lacks the authority to enact the types of regulations proposed by the dissent. For example, under California law, the District lacks the authority to regulate emissions from motor vehicles. See Cal. Health & Safety Code § 39002.  RINNAI AMERICA CORP. V. SCAQMD 23 residential central furnaces); 67 Fed. Reg. 16,640 (Apr. 8, 2002) (approving the District’s NOx emissions standards for boilers, steam generators, process heaters, and water heaters); 73 Fed. Reg. 73,562, 73,570-71 (Dec. 3, 2008) (approving Texas’s NOx emissions standards for water heaters, small boilers, and process heaters); 89 Fed. Reg. 54,358, 54,360 (July 1, 2024) (approving Utah’s NOx emissions standards for gas fired water heaters). In fact, in the case of San Joaquin Valley (which, similar to the District, is in “serious” nonattainment with federal standards), the EPA in 2022 expressed concern that San Joaquin Valley’s proposed SIP was insufficient because, in part, it lacked a zero emissions standard. See 87 Fed. Reg. 60,494, 60,512 (Oct. 5, 2022). The EPA’s approval of these state appliance emissions standards imbues them with “the force and effect of federal law,” which, among other things, makes them enforceable in federal court. Safe Air for Everyone v. E.P.A., 488 F.3d 1088, 1097 (9th Cir. 2007) (quoting Trs. for Alaska v. Fink, 17 F.3d 1209, 1210 n.3 (9th Cir. 1994)); see also § 7604(a), (f)(4). Given the extensive history of federal involvement in the regulation of air pollution, Plaintiffs bear a “heavy burden of showing” that Congress intended for EPCA to intrude upon the intricate regulatory scheme established by the CAA. Epic Sys. Corp. v. Lewis, 584 U.S. 497, 510 (2018). Indeed, when faced with a claimed conflict between two federal statutes, “we come armed with the ‘strong presumption’ that repeals by implication are ‘disfavored’ and that ‘Congress will specifically address’ preexisting law when it wishes to suspend its normal operations in a later statute.” Id. (quoting United States v. Fausto, 484 U.S. 439, 452, 453 (1988) (citation modified)). 24 RINNAI AMERICA CORP. V. SCAQMD Plaintiffs have not offered anything to rebut this presumption. As Plaintiffs concede, the text of EPCA makes no mention of emissions regulations. Nor have Plaintiffs pointed to a single piece of EPCA’s legislative history mentioning emissions regulations of any kind, let alone indicating that EPCA was intended to preempt states’ ability to regulate appliance emissions. At the time of EPCA’s initial passage in 1975, Congress was no doubt aware of the obligations it had imposed on the states through the CAA amendments passed just five years prior. See Pit River Tribe v. Bureau of Land Mgmt., 939 F.3d 962, 971 (9th Cir. 2019) (“[W]e assume Congress is knowledgeable about existing law when it enacts new legislation.”). When EPCA’s preemption provision was later amended in 1987, the District and multiple other state regulators had already promulgated, and the EPA had approved, NOx emissions standards for EPCA-covered appliances. See Hall v. U.S. Dep’t of Agric., 984 F.3d 825, 840 (9th Cir. 2020) (“Congress is presumed to be aware of an agency’s interpretation of a statute.”). Yet at no point in crafting or amending EPCA did Congress choose to include language calling into question the states’ ability to comply with their obligations under the CAA by enacting appliance emissions regulations. Moreover, when Congress amended the CAA in 1990 to strengthen its enforcement efforts against nonattainment areas, Congress once again did not address, let alone express concern about, EPCA preemption. Neither Plaintiffs nor the dissent contend otherwise. Instead, Plaintiffs and the dissent rely on a catchall provision in the CAA stating that a state’s SIP must include assur