# United States Court **of Appeals**  **f or the Fifth Circuit** 

**____________**
No. 23

- 60234

**____________ Sierra Club,** 

Petitioner **,**

versus

**Louisiana Depa**  **rtment of Environmental Quality; Roger W. Gingles,**  in his official capa city as Secretary, Louisiana Depa rtment of Environmental Quality **,** Respondents

**.**

**______________________________** Petition for Review of an Order of the Civil Aeronautics Board Agency N os. 0560

- 00997

- V0, **PSD**

- LA

- 841

**______________________________** Before **Stewart ,**  **Duncan ,**  and **Engelhardt,** Circuit Judges

**. Kurt D. Engelhardt,**  Circuit Judge **:** This case involves a challenge to the pre

- construction permits issued by the Louisiana Depa rtment of Environmental Quality (“ **LDEQ** ”) to Commonwealth **LNG** , LLC (“Commonwealth”) for its planned liquefied natural gas (“ **LNG** ”) export facility in Cameron Parish, L ouisiana. Petitioner Sierra Club asks this Court to vacate **LDEQ** ’s permitting decision as arbitrary and contrary to law, arguing that the facility’s emissions will exceed National Ambient Air Quality Standards (“ **NAAQS** ”) and that **LDEQ** failed to require Commo nwealth to use the best available control United States Court of Appeals Fifth Circuit 

### FILED April 29, 2024 Lyle W. Cayce Clerk Case: 23-60234 Document: 142-1 Page: 1 Date Filed: 04/29/2024technology (“ **BACT** ”) to limit those emissions. For the following reasons,

we **DENY** Sierra Club’s petition for review and affirm **LDEQ** ’s permitting decision.

I. Factual and Regulatory Background
Commonwealth, an **LNG** 1 dev elopment company, plans to build an
**LNG** liquefaction and export facility in Cameron Parish, Louisiana, on the west bank of the Calcasieu Ship Channel at the Gulf of Mexico. Before beginning construction on its project, Commonwealth must obtain various fede ral, 2 state, and local authorizations. At issue here are authorizations issued by **LDEQ** following an analysis of the facility’s projected air
emissions. Commonwealth’s facility is projected to produce air emissions regulated by the Clean Air Act (“ **CAA** ”) , w hich “establishes a comprehensive program for controlling and improving the nation’s air quality through state and federal regulation.” BCCA Appeal Grp. v. U.S.
E.P.A. , 355 F.3d 817, 821

– 22 (5th Cir. 2003), as amended on denial of reh’g and reh’g en banc ( Jan. 8, 2004); 42 U.S.C. § 7401 et seq. Under the **CAA** , the States work in concert with the Environmental Protection Agency (“ **EPA** ”) to regulate air pollution emissions from stationary sources

— the **CAA** thus
operates as “ [ a ] n experiment in cooperative federalism.” Luminant Generation Co. v. U.S. E.P.A. , 675 F.3d 917, 921 (5th Cir. 2012) (citation

**_____________________**

1 Liquified natural gas is natural gas that has been cooled to a liquid state for shipping and storage purposes

.

2 On August 20, 2019, Commonwealth filed its application for approval of the proposed facility with the Federal Energy Regulatory Commission (“ **FERC** ”) pursuant to Section 3(a) of the Natural Gas Act. On September 9, 2022, **FERC** issued its extensive review of the proposed **LNG** project, and on November 17, 2022, **FERC** issued a final order approving the project. Sierra Club does not challenge **FERC** ’s order in this appeal. Case: 23-60234 Document: 142-1 Page: 2 Date Filed: 04/29/2024omitted). This regulatory scheme is relatively simple: the **EPA** establishes **NAAQS** for specific air pollutants, and the States are re sponsible for implementing those standards. Id. ; see 42 U.S.C. § 7407(a) (“Each State shall have the primary responsibility for assuring air quality within the entire geographic area comprising such State.”).

The **NAAQS** program requires the **EPA** to identify air pollutants that “may reasonably be anticipated to endanger public health or welfare.” 42 U.S.C. § 740 8 (a)(1)(A). Then, the “ **EPA** identif[ies] the maximum airborne concentration of a pollutant that the public health can tolerate, decrease[s] the concentr ation to provide an ‘adequate’ margin of safety, and set[s] the standard at that level.” Whitman v. Am. Trucking Ass ’ ns , 531 U.S. 457, 465 (2001). There are currently **NAAQS** for six pollutants: carbon monoxide (“CO”), lead, nitrogen dioxide (“NO 2 ”), ozone, particulate matter (“PM 10 /PM 2.5 ”), and sulfur dioxide (“SO 2 ”). See generally 40 C.F.R. §§ 50.4

– 19. To ensure air quality within its borders satisfies the **NAAQS** , a State must “submit[] an implementation plan . . . which will specify the manner in which nati onal primary and secondary ambient air quality standard s will be achieved and maintained.” 42 U.S.C. § 7407(a). The **EPA** is then “required to approve each State’s plan” if it is satisfied the State Implementation Plan (“ **SIP** ”) meets the **CAA** ’s general conditi ons. Train v. Nat. Res. Def. Council, Inc. , 421 U.S. 60, 66 (1975); 42 U.S.C. § 7410(k)(3). The **EPA** has approved Louisiana’s **SIP**

. See 40 C.F.R. § 52.970(c). To certify that potential new sources of pollution do not erode air quality, each State’s **SIP** “must include permitting programs for the construction or modification of stationary sources.” Luminant Generation
Co. , 675 F.3d at 922. Such permit programs are termed “ New Source Review ” programs. Id. For “attainment areas,” or areas where the air quality Case: 23-60234 Document: 142-1 Page: 3 Date Filed: 04/29/2024is currently compliant with **NAAQS** , the permitting process is called the Prevention of Significant Deterioration (“ **PSD** ”) program. See generally LAC 33:III:509. “The **PSD** requirements, enacted as part of 1977 amendments to the [ **CAA** ], are designed to ensure that the air quality in attainment areas or areas that are already clean will not degrade.” Alaska Dep’t of Env’t Conservation v. E.P.A. , 540 U.S. 461, 470 (2004) (inter nal citations and quotations omitted).

The **PSD** program requires new sources to obtain a specific preconstruction permit. 42 U.S.C. § 7475. To receive the permit, the owner or operator of the proposed facility must demonstrate “that emissions from

construct ion or operation of such facility will not cause, or contribute to, air pollution in excess of” the **NAAQS**

. Id. at § 7475(a)(3). The owner or operator must also show that “the proposed facility is subject to the best available control technology for each po llutant subject to regulation.” Id. at § 7475(a)(4). In Louisiana, **LDEQ** conducts the **PSD** permitting process pursuant to Louisiana’s **SIP**

. 3 See generally LAC 33:III:509. Before issuing a preconstruction permit, **LDEQ** must also provide public notice and an

op portunity to comment on the permit. See 40 C.F.R. § 51.161(a).

In addition to the **PSD** permitting requirements, Congress also requires that each State adopt a Title V operating permit program, whose minimum requirements are set by the **EPA**

. See generally LAC 33

. III

. 507. B. “Title V’s purpose is to provide each source a single permit that contains and consolidates all the information it needs to comply with the [ **CAA** ].” Env’t Integrity Project v. U

. S

. Env’t Prot. Agency , 969 F.3d 529, 536 (5th Cir.

**_____________________**

3 **LDEQ** serves as the legislatively

- created agency “vested with jurisdiction over matters affecting the regulation of the environment” in Louisiana, “including, but not limited to, the regulation of air quality.” St. James v. La

. Dep’t of Env’t Quality , 2023

- 0578, 2024 WL 2078 59, at *2 (La. App. 1 Cir. 1/19/24), reh’g denied (Feb. 15, 2024). Case: 23-60234 Document: 142-1 Page: 4 Date Filed: 04/29/20242020). The **EP A**  has approved Louisiana’s Title V permitting program. See 60 Fed. Reg. 47296

- 01. On April 23, 2021, Commonwealth applied for the required **PSD** and Title V permits for its proposed **LNG** facility. **LDEQ** then began its two

year review of the permit application. In February 2022, **LDEQ** issued a notice inviting public comment on the proposed project. Thereafter, on March 28, 2023, **LDEQ** issued the two permits to Commonwealth, along with its Basis for Decision and its Public Comments Response Summary. On April 27, 20 23, Sierra Club timely filed this petition for review challenging the permitting decision.

II. Standard of Review There is an apparent circuit split as to the appropriate standard of
review for state agency actions . One view is that “[f]ederal courts reviewing state agency action afford the agencies the deference they would receive under state law.” Twp. of Bordentown v. **FERC** , 903 F.3d 234, 270 (3d Cir. 2018). Both **LDEQ** and Commonwealth advocate for this standard of review. The other view is th at the federal Administrative Procedure Act’s (“ **APA** ”) arbitrary and capricious review applies. See Appalachian Voices v. State Water Control Bd. , 912 F.3d 746, 753 (4th Cir. 2019) (reviewing Virginia’s certification under the **APA** ’s standards).

We agree wit h the Third Circuit and others that have adopted the first
view , primarily because “the federal **APA** by its terms does not apply to
states.” Town of Weymouth v. Mass

. Dep’t of Env’t Prot. , 961 F.3d 34, 41 (1st Cir.), on reh’g , 973 F.3d 143 (1st Cir. 2020); see 5 U.S.C.A. § 551(1). Further, a recent decision by this Court applied Texas state law, rather than the **APA** standard, to review a Texas environmental agency’s permitting decision. See Port Arthur Cmty. Action Network v. Tex

. Comm’n on Env’t Quality , 86 F.4th 653 (5th Cir. 2023), opinion withdrawn and superseded on denial of reh’g , No. Case: 23-60234 Document: 142-1 Page: 5 Date Filed: 04/29/202422

- 60556, 2024 WL 655983 (5th Cir. Feb. 16, 2024) (noting the parties’ agreement that the Court “should apply the standard of review that would apply to [the agency] in Tex as state courts”). Thus, we apply Louisiana law to review **LDEQ** ’s permitting decision here. 4 Under Louisiana law, a court “may reverse or modify” a state agency’s “decision if substantial rights of the appellant have been prejudiced because the administrative findings, inferences, conclusions, or decisions are . . . [a]rbitrary or capricious or characterized by abuse of discretion or clearly unwarranted exercise of discretion.” La. R.S. § 49:978.1(G)(5). “The test for determining whether an actio n was arbitrary or capricious is whether the action taken was ‘without reason.’” Save Our Hills v. L a. Dep’t of Env’t Quality , 266 So.3d 916, 927 (La. App. 1 Cir. 11/5/18), writ denied , 267 So.3d 87 (La. 3/18/19) (quoting Dow Chemical Co. La

. Operations Complex Cellulose and Light Hydrocarbons Plants, Part 70 Air Permit Major Modifications and Emission v. Reduction Credits , 885 So.2d 5, 10 (La. App. 1 Cir. 9/17/04)). “Reviewing courts s hould not reverse a substantive decision on its merits, unless it be shown that the actual balance of costs and benefits that was struck was arbitrary or clearly gave insufficient weight to environmental protection.” Save Ourselves, Inc. v. La

. Env’t Contr ol Comm’n , 452 So.2d 1152, 1159 (La. 1984). “However, if the decision was reached procedurally, without individualized consideration and balancing of environmental factors conducted fairly and in good faith, it is the courts’ responsibility to reverse.” Id

. “[T]he agency is required to make basic findings supported by evidence and ultimate findings which flow rationally from the basic findings; and it must articulate a rational connection between the facts found and the order

**_____________________**

4 Regardless, because Louisiana’s law concerning agency review is substantially similar to the **APA** ’s standard of review, both likely lead to the same result here

. Case: 23-60234 Document: 142-1 Page: 6 Date Filed: 04/29/2024issued.” Id. “Although we may u phold a decision of less than ideal clarity if the agency’s path may reasonably be discerned, . . . we will not supply a finding from the evidence or a reasoned basis for the commission’s action that the commission has not found or given.” Id. at 1160.

III. Analysis Sierra Club, both during the public comment period and now on appeal, argues that **LDEQ** acted arbitrarily in its analysis of the potential **NAAQS** violations from the Commonwealth facility. Specifically, Sierra Club believes that **LDEQ** ’s use of significa nt impact levels (“ **SIL** s ”) throughout the emissions analysis was improper. Sierra Club further asserts that **LDEQ** compounded its error by relying on AP

- 42 emission factors, “despite **EPA** ’s caution against doing so.” Sepa rately, Sierra Club argues that **LDEQ** fa iled to require **BACT** from Commonwealth with respect to NOx emissions from Commonwealth’s planned combustion turbines and oxidation system. Finally, Sierra Club asserts that **LDEQ** violated its public trustee duty under Louisiana law, which requires **LDEQ** “to evaluate and avoid adverse environmental impacts to the maximum extent possible.” In response, in addition to contesting each of these arguments, **LDEQ** challenges this Court’s jurisdiction to hear Sierra Club’s claim.

a. Whether this Court has subject matter j urisdiction

. **LDEQ** challenges this Court’s jurisdiction over the petition for review, arguing that Sierra Club’s claim arises under state law, not federal law, and lacks a sufficient hook to bring the claim into federal court. Both Sierra Club and Commonwealth, as intervenor, disagree, asserting instead that the unique interplay between the Natural Gas Act (“ **NGA** ”), the **CAA** , and the Louisiana **SIP** provides this Court with exclusive jurisdiction over the petition. Case: 23-60234 Document: 142-1 Page: 7 Date Filed: 04/29/2024First, the **NGA** . The **NGA** is “a comprehensive scheme of federal

re gulation” intended to address the sale and transmission of natural gas. N. Nat. Gas Co. v. State Corp. Comm’n of Kan. , 372 U.S. 84, 91 (1963). As such, “[t]he **NGA** confers upon **FERC** [exclusive jurisdiction] over the transportation and sale of natural gas in interstate commerce for resale.” Schneidewind v. ANR Pipeline Co. , 485 U.S. 293, 300

– 01 (1988). When Congress later passed the Energy Policy Act, it extended the reach of the
**NGA** to the construction, expansion, and operation of **LNG** terminals, such as the one at issue here. See 15 U.S.C. § 717b (e)(1) . The **NGA** thus strips States of the authority to act in this natural gas realm, except under three specifically enumerated statutes, one of which is the **CAA** . 15 U.S.C. § 717b(d).
As noted above, the **CAA** “establi shes a comprehensive program for controlling and improving the nation’s air quality through state and federal regulation.” BCCA Appeal Grp. , 355 F.3d at 821

– 22. Under the **CAA** , the
**EPA** formulates the **NAAQS** , while “States have primary responsibility for impl ementing the **NAAQS** by developing ‘State implementation plans.’” Util. Air Regul. Grp. v. E.P.A. , 573 U.S. 302, 308 (2014) (quoting 42 U.S.C. § 7410). Once the **EPA** approves a particular State’s **SIP** , it can then “delegate to such State any authority . . . to implement and enforce [its] standards.” 42 U.S.C. § 7411(c)(1). Therefore, when States like Louisiana conduct a required review under the **CAA** for the issuance of permits, they are implementing federal law under a system of cooperative federalism. See,

e.g

. , Ammex, Inc. v. Wenk , 936 F.3d 355, 361 (6th Cir. 2019) (concluding that Michigan’s fuel law, made in compliance with **EPA** ’s standards, is federal law, based on “the way courts have consistently treated **SIP** s”).

The fact that **SIP** s have the force and effect of federal law has been recognized by every federal circuit court to address the issue, including this
Circuit. See Env’t Tex

. Citizen Lobby, Inc. v. ExxonMobil Corp. , 968 F.3d 357, Case: 23-60234 Document: 142-1 Page: 8 Date Filed: 04/29/2024373 (5th Cir. 2020), as revised , (Aug. 3, 2020), and following remand , 47 F.4th 408 (5th Cir. 2022), and reh’g en banc granted, vacated , 61 F.4th 1012 (5th Cir. 2023) (noting that “when the **EPA** approves a **SIP** , it becomes federal law”); see also, e.g. , Grp. Against Smog & Pollution, Inc. v. Shenango Inc. , 810 F.3d 116, 120 (3d Cir. 2016) (“Once the **EPA** approves the **SIP** , it becomes binding federal law.”); Indiana v. E.P.A. , 796 F.3d 803, 806 (7th Cir. 2015) (“Once it is approved by **EPA** , a state rule embodied in a **SIP** becomes enforceable federal law.”). We decline to depa rt from our sister circuits on this issue. Thus, c ontrary to **LDEQ** ’s arguments, when **LDEQ** issued the permit, it was acting pursuant to federal law, not merely state law. Importantly, the **NGA** vests jurisdiction for judicial review of permitting decisions in “[t]he United States Court of Appeals for the circuit in which a facility . . . is proposed to be constructed, expanded, or operated.” 15 U.S.C. § 717r(d)(1). Further, the **NGA** provides that such circuit court “shall have original and exclusive jurisdiction over any civil action for the review of an order or action of a Federal agency . . . or State administrative agency acting pursuant to Federal law .” Id. (emphasis added). Based on the clear language of the **NGA** , and the understanding that **LDEQ** acted under federal law in issuing the permits to Commonwealth, we have jurisdiction to review Sierra Club’s petition. See Town of Weymout h , 961 F.3d at 40

– 41 (reviewing State agency’s order acting pursuant to the **CAA** ); Friends of Buckingham v. State Air Pollution Con trol Bd. , 947 F.3d 68, 80 (4th Cir. 2020) (finding jurisdiction pursuant to the **NGA** to review the grant of a permit by the State board). This Court recently decided the merits of a **CAA** challenge to a Texas Commission on Environmental Quality (“ **TCEQ** ”) permitting decision in Port Arthur Cmty. Action Network, supra . There, a not

- for

- profit environmental organization petitioned for review of **TCEQ** ’s decision, pursuant to the federal **CAA** and the Texas Clean Air Act, to grant a **PSD** Case: 23-60234 Document: 142-1 Page: 9 Date Filed: 04/29/2024permit to an **LNG** plant developer. Port Arthur Cmty. Action Network , 86 F.4th at 655

– 56. 5 This Court, after finding that petitioner had standing to bring its claim, analyzed **TCEQ** ’s permitting decision under Texas’s

a rbitrary and capricious standard, apparently finding no issue with the Court’s subject matter jurisdiction to hear the case. Id. at 659

– 60. Consistent with our previous decisions, we hold that this Court has subject matter jurisdiction over Sierra Club’s petition, and thus proceed to the merits. 6

b. Whether **LDEQ** acted arbitrarily in using **SIL** s to consider the Commonwealth permit application.
Sierra Club first argues, based on the **CAA** ’s clear language , that neither the **EPA** nor State agencies may use **SIL** s in permitting decisions. However, even if the Court finds that **SIL** s are valid under the **CAA** , Sierra Club argues that **LDEQ** used them im properly with respect to NO 2 emissions for the Commonwealth **LNG** project. As noted above, the owner or operator of a proposed facility must demonstrate “that emissions from construction or operation of such facility will not cause, or contribute to, air pollution in excess of” the **NAAQS** . 42 U.S.C. § 7475(a)(3). Sierra Club

**_____________________**

5 On February 16, 2024, th e panel in the Port Arthur case denied rehearing, withdrew its previous opinion, and issued a new opinion that certified a question to the Supreme Court of Texas concerning Texas’s definition of “best available control technology.” Port Arthur Cmty. Action Network v. Tex

. Comm ’ n on Env ’ t Quality , No. 22

- 60556, 2024 WL 655983 , at *2 (5th Cir. Feb. 16, 2024) . Because the certified question deals solely with the interpretation of Texas law, rather than the Court’s ability to review the permitting decision, the panel’s new opinion does not affect our jurisdiction analysis here.

6 **LDEQ** directs our attention to Shrimpers & Fishermen of RGV v. Tex

. Comm ’ n on Env ’ t Quality , 968 F.3d 419, 427 (5th Cir. 2020) (Oldham, J., concurring), in which a concurring judge suggests that federal courts may lack

— or perhaps should lack

— jurisdiction over petitions for review of **LNG** permits brought under the **APA** and **NGA**

. This Court did not decide the jurisdiction issue in Shr impers & Fishermen because it concluded that the petitioners did not have standing; therefore, the discussion of jurisdiction is not controlling here , nor does it persuade us to depa rt from the reasoning laid out above. Case: 23-60234 Document: 142-1 Page: 10 Date Filed: 04/29/2024argues that Commonwea lth’s **LNG** facility will in fact cause or contribute to violations of the **NAAQS** , yet **LDEQ** issued the preconstruction permits anyway based on a fundamentally flawed analysis.

i. Whether the use of **SIL** s complies with the **CAA**

. Sierra Club argues that **LDEQ** arbitra rily concluded that Commonwealth’s facility will not cause or contribute to a **NAAQS** violation by conducting a shortened Air Quality Analysis based on **SIL** s. **SIL** s are numerical values “below which the **EPA** considers a source to have an insignificant effect on ambient air quality.” Sierra Club v. E.P.A. , 705 F.3d 458, 461 (D.C. Cir. 2013). **EPA** guidance suggests that when a source demonstrates that its impact will not exceed the **SIL** , the source does not need to conduct the more extensive air quality analysis that is typically required. See id. ; AR75:5. The use of **SIL** s arose out of the **EPA** ’s decades

long belief that requiring extensive air modeling for every source is costly and overl y burdensome, especially where the source is projected to emit insignificant amounts of pollution. AR75:5. “In 2010, **EPA** attempted to codify these uses of **SIL** s,” but, after recognizing various flaws in the proposed **SIL** s rule, the **EPA** asked the D.C. Circuit to vacate the rule. Sierra Club v. Env’t Prot. Agency , 955 F.3d 56, 59 (D.C. Cir. 2020) 7 ; see 40 C.F.R. § 51.165(b)(2) (allowing for use of **SIL** s to determine if a source would “exceed the following significance levels”). On remand in that case, the **EPA**

c hose to issue non

- binding guidance, rather than a modified rule, explaining

**_____________________**

7 Notably, Sierra Club asked the D.C . Circuit to hold that the **EPA** could not use **SIL** s at all in its air quality modeling. Sierra Club v. E.P.A. , 705 F.3d 458 , 464 (D.C. Cir. 2013) . However, th at court declined to do so, instead holding that “[o]n remand the **EPA** may promulgate regulations that do not include **SIL** s or do include **SIL** s that do not allow the construction or modification of a source to evade the requirements of the [ **CAA** ].” Id. C ontrary to Sierra Club’s suggestion, the D.C. Circuit has never held that **SIL** s are per se invalid under the **CAA**

. Case: 23-60234 Document: 142-1 Page: 11 Date Filed: 04/29/2024how state permitting authorities

— like **LDEQ**

— can rely on **SIL** s in the
**PSD** permitting process.

Based on this **EPA** guidance, **LDEQ** uses **SIL** s to determine whether a permit applicant has sa tisfied “the requirement to demonstrate that they do not cause or contribute to a violation by showing that the ambient air quality impacts resulting from the proposed source’s emissions would be below these concentration levels.” AR75:5; LAC 33:III.509. F or any given permit application, **LDEQ** conducts a “preliminary screening” whereby it identifies the projected emissions and compares them to the **EPA** ’s **SIL** s for each **NAAQS** . Only for those pollutants that exceed the **SIL** value does **LDEQ** conduct “refined modeli ng” to further analyze the projected effect on air quality. AR70:35. In sum, **LDEQ** uses the **SIL** s as a “compliance demonstration tool” to simplify the air analysis and “help[] to reduce the burden on permitting authorities and permit applicants to conduct of ten time

- consuming and resource

- intensive air dispersion modeling” where such modeling is unnecessary to show compliance with the **CAA** . AR75:5. For the Commonwealth facility, **LDEQ** found that only four of the pollutants measured above the **SIL** s and thus requi red refined modeling. AR70:35.

Sierra Club asserts that the **EPA** guidance and **LDEQ** ’s use of **SIL** s violate the **CAA** because the **CAA** “does not allow de minimis exceptions to an applicant’s responsibility to demonstrate that it will not cause or contribute to a **NAAQS** violation.” Sierra Club finds support for this argument in the “broad, sweeping language” of the **CAA** , which restricts

any source that will “cause, or contribute to” a **NAAQS** violation. Sierra Club cites to Bluewater Network v. E.P.A. , 370 F.3d 1, 13 (D.C. Cir. 2004), for the proposition that the word “contribute” as used in the **CAA** “has no inherent connotation as to the magni tude or importance of the relevant ‘share’ in the effect; certainly it does not incorporate any ‘significance’ requirement.” Sierra Club further points out that, elsewhere in the **CAA** , Case: 23-60234 Document: 142-1 Page: 12 Date Filed: 04/29/2024Congress modified the word “contribution” with the word “significant” bu t chose not to include that modifier in section 7475(a). See, e.g. , 42 U.S.C. § 7407(d)(4) (v) (excluding from nonattainment areas portions where a state demonstrates the sources “do not contribute significantly to a violation” of **NAAQS** ); § 7426 (limiting a pplicability of interstate pollution notification requirements to new sources that “significantly contribute to levels of air pollution in excess of” **NAAQS** ). Based on this statutory language, Sierra Club argues that neither the **EPA** nor **LDEQ** can alter the **C AA**  ’s requirements by limiting air quality analyses to only those sources that “significantly” contribute to **NAAQS** violations.
In response, **LDEQ** asserts that neither the **CAA** nor Louisiana’s
**SIP** mandate any specific modeling analysis; rather, Congress gave t he **EPA** broad authority to determine how to demonstrate compliance with **NAAQS**

. AR75:4. And under this broad authority, the **EPA** has recommended that the
**SIL** screening process can suffice to make the necessary demonstration. See Sierra Club v. U .S. Env’t Prot . Agency , 939 F.3d 649, 686 (5th Cir. 2019) (“The **EPA** ’s selection of modeling methods . . . is exactly the type of decision for which ‘significant deference’ is appropriate.”). **LDEQ** explained in its Public Comments Response Summary that “[t]he air quality concentration levels that the **EPA** has identified as **SIL** s do not function to exempt a source from making the demonstration required.” AR71:33. Instead, the **SIL** s “provide a streamlined means” of showing compliance with the **CAA**

— in other words, the **SIL** analysi s itself is the required demonstration. AR71:33; AR91:14. Further, in response to Sierra Club’s textual arguments, **LDEQ** points out that the D.C. Circuit, upon which Sierra Club relies heavily, has often observed that the term “contribute” is ambiguous. See Catawba Cnty.
v. E.P.A. , 571 F.3d 20, 35 (D.C. Cir. 2009) (listing “contribute” as one of many words in a statute “suggest[ing] a congressional intent to leave Case: 23-60234 Document: 142-1 Page: 13 Date Filed: 04/29/2024unanswered questions to an agency’s discretion and expertise”); Env’t Def. Fund, Inc. v. E.P.A. , 82 F.3d 451, 459 (D.C. Cir.), amended sub nom. Env’t Def. Fund v. E.P.A. , 92 F.3d 1209 (D.C. Cir. 1996). Thus, **LDEQ** asserts that the
**EPA** ’s determination that only “significant” contributions require extensive air analyses should be afforded deference as a reasonable reading of the word “contribute.” **LDEQ** also points to the label Congress chose for the **PSD**

program

— “Prevention of Significant Deterioration”

— as a helpful clue in determining C ongressional intent. See 42 U.S.C. § 7470 et seq. (emphasis added). According to **LDEQ** , Congress gave the **EPA** “discretion to set the conditions for determining whether a **PSD** applicant has complied with” the
**CAA** , and thus, the **EPA** was well within its authority in allowing state agencies like **LDEQ** to use **SIL** s. AR91:8.

We agree with **LDEQ** and Commonwealth that the **CAA** does not specify how a permit applicant or permitting authority must make the required air quality demonstration. AR75:4. The plain language of the **CAA** “authorizes the **EPA** to determine how the analysis is to be conducted, including the use of air quality models.” AR75:4; see 42 U.S.C. § 7475(e)(1) (“The review provided for in subsection (a) shall be preceded by an analysis in accordance with regulations of the Administrator, promulgated under this subsection . . .”). The plain language of the **CAA** does not, however, define “contribute,” a word that courts have consistently found to be ambiguous. See, e.g. , Catawba Cnty

. , 571 F.3d at 35. The **EPA** ’s interpretation of “contribute” to allow for **SIL** s and a shortened air quality analysis for insignificant pollutants should therefore be given deference, where it reasonably accounts for both the goals of the **CAA** and the public’s interest in economic growth. See 42 U.S.C. § 7470 (explaining Congressional declaration of purpose for the **CAA** ); see also Groce v. Dep’t of Env’t Prot. , 921 A.2d 567, 578 (Pa. Commw. Ct. 2007) (analyzing identical arguments regarding **SIL** s and finding that “Congress did not intend to prohibit any and Case: 23-60234 Document: 142-1 Page: 14 Date Filed: 04/29/2024all economic growth based on i nfinitesimally small values calculated using highly developed and developing software”). **LDEQ** did not abuse its discretion in relying on reasonable **EPA** guidance to use **SIL** s to calculate which pollutants will have an insignificant effect on the **NAAQS**

. Furth er, it is worth noting that, for the four pollutants found to be in excess of the **SIL** s, **LDEQ** and Commonwealth went on to conduct a “full impact analysis” to assess compliance with **NAAQS** . AR70:35; AR71:33; AR90. This additional analysis modeled the facility ’s projected pollutants together with background sources located off

- site, stretching as far as twenty kilometers away. AR90:4

- 228

- 229; AR10:20

- 21. After this analysis, only one pollutant exceeded the **NAAQS** : one

- hour emissions of NO 2 . AR90:4

- 228

- 229; AR10: 41

- 44. Commonwealth and **LDEQ** th e n conducted a sepa rate “source contribution analysis” for NO 2 , which is discussed further below.
AR90:4

- 390; AR10:41. Looking at the air analyses as a whole, we cannot say that **LDEQ** and Commonwealth cut corners or arbitraril y ignored exceedances of **NAAQS** . Based on the extensive testing done, and the deference owed to the **EPA** in determining how that testing is to be done, we affirm **LDEQ** ’s use of **SIL** s in its permitting decision.

ii. Whether **LDEQ** reasonably applied the **SIL** for NO 2 . Sierra Club next argues that, even if **SIL** s are valid under the **CAA** , **LDEQ** did not apply them properly with respect to NO 2 . As mentioned, **LDEQ** and Commonwealth conducted “refined modeling” for NO 2 because the emission impacts were projected to be a bove the **SIL** s. AR69:5. As shown in the refined modeling table in **LDEQ** ’s report, for the one

- hour averaging emissions period, the total NO 2 concentration for the area was projected to be over the **NAAQS** . AR69:6. Sierra Club seizes on the results of this mode ling to contend that “ **LDEQ** could not issue Commonwealth’s
**PSD** permit without requiring mitigation to offset Commonwealth’s NO 2 Case: 23-60234 Document: 142-1 Page: 15 Date Filed: 04/29/2024impacts.” Sierra Club made these exact arguments during the public comment period, and **LDEQ** responded by explaining in detail its reasoning for approving the Commonwealth permits despite the initial modeling.
AR71:34

– 42. First, **LDEQ** noted that “modeled exceedances of a **NAAQS** do not necessarily equate to actual exceedances of a **NAAQS** .” AR71:40. In fact, the modeling replicates a wors t

- case scenario, assuming the worst

- case emissions from many industrial facilities in the area, combined with worst

case meteorological conditions. AR71:40. According to **LDEQ** , the modeling created a circumstance that was “improbable at best and, given the number of sources modeled, likely never to occur.” AR71:40. However, even in this worst

- case scenario wherein all modeled sources emit their maximum pollution, that alone is still unlikely to cause an exceedance of **NAAQS** . This is because the exceedances ar e only expected when “background” concentration is added in, and according to **LDEQ** , this is a “highly conservative exercise” because “the actual measured ambient concentrations used to represent background are in fact representative and inclusive of contri butions from the existing emission sources included in the model.” AR71:40

– 41. In other words, **LDEQ** ’s predictions “double count” the effect of existing sources in the area. AR71:41.

The **EPA** has issued guidance for what a state permitting agency should do w hen “a cumulative impact analysis predicts a **NAAQS** violation.” AR71:40. In this scenario, **LDEQ** may “compar[e] the proposed source’s modeled contribution to that violation to the corresponding **SIL** value.” AR71:40. “If the modeled impact is below the recommended **SIL** value at the violating receptor during the violation, the **EPA** believes this will be sufficient in most cases for a permitting authority to conclude that the source does not cause or cont ribute to (is not culpable for) the predicted violation.” AR71:40 (emphasis removed). **LDEQ** and Commonwealth Case: 23-60234 Document: 142-1 Page: 16 Date Filed: 04/29/2024followed this guidance and found that the facility’s contribution to the exceedance of the one

- hour NO 2 **NAAQS** would be 0.07 μg/m 3 , far below the **SIL** of 7.5 μg/m 3 . AR71:42. Thus, **LDEQ** concluded that the facility’s potential contribution to any exceedance of **NAAQS** , as shown in the worst

case scenario modelling, would be negligible. AR71:42. As a result, **LDEQ** found additional mitigation measures unnecess ary. AR71:42. Although Sierra Club asserts that **LDEQ** compounded the **SIL** s error by relying on the **SIL** for NO 2 twice

— once in the preliminary screening, and once in the post

- refined

- modeling comparison

— **LDEQ** followed relevant
**EPA** guidance precisely, all while explaining its entire process. This does not appear to be a case where a State agency issued its decision “without
reason.” Reduction Credits , 885 So.2d at 10. Considering the detailed modeling that **LDEQ** conducted and the vast amount of **EPA** guidance

suppor ting its analysis, we affirm **LDEQ** ’s use of **SIL** s to approve the permits despite the initial modeled NO 2 emissions.

iii. Whether **LDEQ** ’s reliance on AP

- 42 factors was arbitrary

. Finally, Sierra Club argues that, validity of **SIL** s aside, **LDEQ** ’s use of AP

- 42 emissions factors “factually undermined” the **SIL** s analysis, making the permitting decision arbitrary and contrary to law. The AP

- 42 emissions factors are “representative value[s] that attempt[] to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant.” **EPA** , Basic Information of Air Emissions Factors and Quantification , https://www. **EPA** .gov/air

- emissions

- factors

and

- quantification/basic

- information

- air

- emissions

- factors

- and

quantification#About%20Emissions%20Factors (Nov. 30, 2023). The **EPA** developed the AP

- 42 emissions factors for various combustion sources, so that new sources that have yet to be built

— such as the Commonwealth facility

— can look to the factors to determine projected operational Case: 23-60234 Document: 142-1 Page: 17 Date Filed: 04/29/2024emissions. AR71:118. Here, **LDEQ** and Commonwealth used AP

- 42 factors as “default emission factors” to predict the likely pollutant outputs for the facility. AR71:118.

In contest ing **LDEQ** ’s analysis, Sierra Club emphasizes the **EPA** ’s

warn ing in a 2020 guidance letter that “AP

- 42 emission factors should only be used as a last resort” because they “are not likely to be accurate predict or s of emissions from any one specific source.” AR37:195 (emphasis removed); AR71:114. However, **LDEQ** and Com monwealth point out that the **EPA** only cautioned against AP

- 42 factors when used “in place of more representative source

- specific emissions value[s].” AR71:114. **LDEQ** argues that AP

- 42 emissions factors are almost always required for projects like Commonweal th’s because there are not yet direct emissions to monitor; the facility has not been built, so it does not emit any measurable pollutants yet. Commonwealth makes the same argument, emphasizing that “this is a preconstruction permit and direct, site

- specif ic emissions information is not available.” Considering the specific fact ual scenario here , and where the
**EPA** has suggested that AP

- 42 emissions factors are suitable for this exact

s ituation , it was not an abuse of discretion for **LDEQ** and Commonwealth to

u se AP

- 42 factors in their air quality analysis

. E ven if relying on the AP

- 42 factors themselves was not arbitrary, Sierra Club argues that **LDEQ** should have relied on the “maximum” factors, rather than the “average” factors, for its analysis. According to Sierra Club, record evidence demonstrates that relying on the “maximum” factors “would roughly triple Commonwealth’s potential to emit annual
NO x pollution.” However, **LDEQ** considered this argument in its Basis for Decision and found that the extreme ends of the factor ranges are not likely to be representative of actual emissions for the Commonwealth project. AR71:107. For example, when responding to a comment that **LDEQ** should use the maximum factor for fugitive **VOC** emissions, **LDEQ** explained that Case: 23-60234 Document: 142-1 Page: 18 Date Filed: 04/29/2024the use of the average factor was reasonable because it was not reasonable to “expect every component at any facility to be leaking at an extraordinarily high rate.” AR71:108. **LDEQ** did not act arbitrarily or contrary to law in using the average AP

- 42 emission factors, set by the **EPA** , to determine potential emissions from an **LNG** facility that has not yet been built.

c. Whether **LDEQ** acted arbitrarily in authoriz ing the project’s **BACT**

. Sierra Club next argues that **LDEQ** failed to require **BACT** for NOx emitted from two sources of pollution in the facility: (1) Commonwealth’s combustion turbines; and (2) Commonwealth’s oxidation system. While acknowledging that “the applicant is not required to select the most effective control option or the lowest emission limit that option is capa ble of,” Sierra Club asserts that “the applicant must justify selecting anything other than the most protective available option.” Here, Si erra Club believes **LDEQ** failed to require that justification from Commonwealth and instead excused incomplete emission analyses for **BACT** on the proposed **LNG** facility. First, some background on the **BACT** requirement. A key aspect of the **PSD** permitting proces s requires the owner or operator of a new stationary source to apply the **BACT** for the source’s expected air pollutants

— in simple terms, the facility must use the technology that best limits emissions. The **CAA** specifically requires **LDEQ** to determine that th e proposed facility will be outfitted with the **BACT** for “each pollutant subject to regulation.” 42 U.S.C. § 7475(a)(4). The **EPA** has established a five

- step, top

- down approach for determining the **BACT** : (1) identify all available control technologies; (2) eliminate the technically infeasible options; (3) rank the remaining control technologies by effectiveness; (4) evaluate the total impacts of the most effective control technologies and document results; and (5) select the **BACT** . LAC 33:III:509; AR70:5

– 6. “Th e most effective control option not eliminated in step 4 is selected as Case: 23-60234 Document: 142-1 Page: 19 Date Filed: 04/29/2024**BACT** .” AR70:6. While not a binding rule, **LDEQ** consistently uses this
**EPA** guidance for its **PSD** permitting program.

“ **BACT** determinations are intrinsically case

- by

- case determinations.” P ort Arthur Cmty. Action Network , 86 F.4th at 663. The analysis “tak[es] into account energy, environmental, and economic impacts and other costs.” 40 C.F.R. § 52.21(b)(12). It follows that this analysis requires “expertise, experience, and procedural mecha nisms” from **LDEQ** ’s end to conduct as thorough of a review as possible. Zen

- Noh Grain Corp. v. Consol. Env’t Mgmt., Inc. , No. CIV.A. 12

- 1011, 2012 WL 6201871, at *10 (E.D. La. Dec. 12, 2012), amended on denial of reconsideration , No. CIV.A.

12

- 1011, 2013 WL 3947186 (E.D. La. July 31, 2013). In the present case, Sierra Club takes issue with two of **LDEQ** ’s
**BACT** determinations. The first deals with NOx emissions from Commonwealth’s nine gas

- fired combustion turbines. Sierra Club asserts that the most effe ctive technology to control emissions from these turbines is a selective catalytic reduction (“ **SCR** ”) system paired with dry low NOx burners. The main disagreement here centers around the approved numerical emission limit of 2.5 ppmvd, compared to Sierra Cl ub’s proposed 2.0 ppmvd limit based on its theory for increasing the system’s effectiveness. However, as **LDEQ** explained in its response to Sierra Club’s public comment on this issue, the effectiveness of the **SCR** system is “dependent on many variables” and in reality, operates at a wide range of efficiency. AR71:80. In other words, reducing the emissions by 0.5 ppmvd is not as simple as Sierra Club makes it sound. **LDEQ** also addressed Sierra Club’s assertion that many other facilities have achieved 2.0 ppmvd emission numbers, noting that these other facilities are not comparable to the Commonwealth project because they include “only combined cycle turbines located at electrical generation facilities.” AR71:83. Commonwealth’s facility will be built differently, in a different environment than other Case: 23-60234 Document: 142-1 Page: 20 Date Filed: 04/29/2024facilities. See AR71:83. Ultimately, **LDEQ** concluded that the **BACT** determination of 2.5 ppmvd for the turbines was “appropriate and reasonable” based on its thorough analysis. AR71:83.

The second determination concerns NOx emissions from Commonwealth’s oxidation system, which will use thermal oxidizers to remove impurities from the natural gas before it is liquefied. Sierra Club asserts that Commonwealth failed to consider a catalytic oxidizer, which could result in low er overall NOx emissions. In its response to public comments, however, **LDEQ** explained that, for a number of reasons, “the use of catalytic oxidizers rather than thermal oxidizers . . . is not technically feasible.” AR71:100. **LDEQ** highlighted the additional pollution that the catalytic oxidizer would emit and explained that Commonwealth would need to include additional machinery

— that also could emit additional pollutants

— to combat the side effects of the oxidizer. AR71:100. In sum, “[t]he addition of a scrub ber to remove the trace constituents, a system to manage the scrubber waste stream, and a natural gas

- fired heater to raise the temperature of the acid gas streams would needlessly add complexity to the system, would increase capital and operating costs, a nd would be an additional source of air emissions.” AR71:100. **LDEQ** argues that this analysis suffices to establish the **BACT** and that, contrary to Sierra Club’s assertions, cost estimates are not required as additional support for its conclusion.

As is evid ent from the administrative record, **LDEQ** carefully responded to and rejected each of Sierra Club’s proposed **BACT** s during the public comment period. While Sierra Club’s proposed control technologies may be effective at reducing emissions, Sierra Club has fa iled to show anything more than possible (and potentially infeasible) alternatives to **LDEQ** ’s already reasonable decisions. See St. James , 2024 WL 207859, at *43

– 44 (holding that where the agency’s basis for decision reflected its Case: 23-60234 Document: 142-1 Page: 21 Date Filed: 04/29/2024consideration of emissions , their impact on the environment, and **BACT** on those emissions, its determination was not arbitrary or capricious). Sierra Club’s desire for Commonwealth to use different technology at its facility does not mandate a conclusion that **LDEQ** acted arbitrarily in approving the
**BACT** that Commonwealth plans to use.

Because **LDEQ** considered all relevant factors and articulated reasons for its decisions regarding these specific technologies, this Court will not disturb technical determinations made within **LDEQ** ’s expe rtise. See Alaska Dep’t of Env’t Conservation , 540 U.S. at 490 (explaining that, for the purposes of **BACT** , the **EPA** disapproves a permit only in relatively rare circumstances where “a state agency’s **BACT** determination is not based on a reasoned analysis”) (quotation marks omitted); see also Maryland v. E.P.A. , 958 F.3d 1185, 1196 (D.C. Cir. 2020) (emphasizing that courts “give an extreme degree of deference to [an agency’s] evaluation of scientific data within its technical expertise”) (citation and internal quotation omitted) )

. We decline to wade into these hyper

- technical waters and supplant **LDEQ** ’s careful determinations, made with the benefit of time

- consuming testing and extensive analysis.

d. Whether **LDEQ** violated Louisiana’s public trustee duty when consid ering the permit application. Article IX § 1 of the Louisiana Constitution establishes “[a] public trust for the protection, conservation and replenishment of all natural resources of the state.” Save Ourselves , 452 So.2d at 1154. In conjunction with

t he constitutional standard, the Louisiana legislature codified a public trust ee duty to require an analysis of “[t]he potential and real adverse environmental effects” of any proposed project that may affect air quality. La. R.S. § 30:2018(B)(1). Pursuant to the public trust doctrine, then, **LDEQ** must “determine that adverse environmental impacts have been minimized or avoided as much as possible consistently with the public welfare.” Save Case: 23-60234 Document: 142-1 Page: 22 Date Filed: 04/29/2024Ourselves , 452 So.2d at 1157. Sierra Club argues that, by granting the preconstruction permits to Commonwealth here , **LDEQ** violated th e public trust doctrine. Essentially, Sierra Club makes similar arguments concerning
**SIL** s and **BACT** detailed above, but asserts that **LDEQ** was required to go above and beyond its **CAA**

- based review of these issues to comply with its public trustee duty.
**LDEQ** provides three main responses: (1) this Court does not have subject matter jurisdiction to review **LDEQ** ’s compliance with state law that is not included in the State’s **SIP** ; (2) the Natural Gas Act preempts the public trust d octrine 8 ; and (3) regardless, **LDEQ** did not violate its public

trust ee d uty . Commonwealth focuses primarily on argument (3), asserting that **LDEQ** ’s decision complied with its public trustee duty.

As to **LDEQ** ’s first argument, Sier ra Club is correct that Louisiana’s public trust doctrine has been incorporated into the **SIP** and is properly before the Court now. I n approving Louisiana’s **SIP** , the **EPA** specifically incorporated LAC 33:III.101 and 111, which in turn authorize **LDEQ** to issue permits in accordance with La. R.S. § 30:2001 et seq. See LAC 33:III.101(A)

– (B). Because of the explicit reference to the Louisiana statute that contains the codified public trust doctrine, the doctrine acts as part of Louisiana’s
**SIP**

. See LAC 33:III.501.A; LAC 33:III.537.A.II. Further, Louisiana courts have held that “all issues arising in the context of **LDEQ** permit applications are public trustee issues; to find that **LDEQ** acts as a public trustee only with respect to certain portions of its determinations . . . would be absurd.” City of Baton Rouge v. La

. Dep’t of Env’t

**_____________________**

8 **LDEQ** ’s arguments concerning preemption seem to rely on a scenario where its permitting decision was consistent with the **CAA** and Louisiana’s **SIP** but i nconsistent with the public trust doctrine. Because we ultimately find that **LDEQ** ’s permitting decision was consistent with both, we do not address the alleged conflict between the two. Case: 23-60234 Document: 142-1 Page: 23 Date Filed: 04/29/2024Quality , 172 So.3d 13, 23 (La. App. 1 Cir. 4/28/15). In other words, **LDEQ** ’s compliance with its public t rustee duty is inextricably intertwined with its permitting analysis, and to sepa rate the two would create confusion and possible conflicting conclusions between state and federal courts reviewing different aspects of the same permitting decisions. And, as a practical consideration, any argument by **LDEQ** that it was not required to abide by a public trustee duty is belied by **LDEQ** ’s own permitting decision, which contains detailed analyses of its compliance with that duty. See AR71. For these reasons, Sierra Club’s arguments concerning the Louisiana public trust doctrine are properly before us on appeal

. As for the merits, **LDEQ** satisfied its public trustee duty here. In Save Ourselves, Inc. v. La

. Env’t Control Comm’n , the Louisiana Supreme Court outlined the issues to be considered by the permit applicant and **LDEQ** under the public trust doctrine. 452 So.2d at 1157. These issues are now known as the “IT Questions,” and **LDEQ** analyzes them as three sepa rate inquiries: (1) whether “the potential and real adverse e nvironmental effects of the proposed facility [have] been avoided to the maximum extent possible”; (2) whether “a cost benefit analysis of the environmental impact costs balanced against the social and economic benefits of the proposed facility demonstrate that the latter outweighs the former”; and (3) whether “there [are] alternative projects which would offer more protection to the environment than the proposed facility without unduly curtailing non

environmental benefits.” Matter of Rubicon, Inc. , 670 So .2d 475, 482 (La. App. 1 Cir. 2/14/96) (explaining the “IT Decision” from Save Ourselves ); see also Blackett v. La

. Dep’t of Env’t Quality , 506 So.2d 749, 753

– 54 (La. Ct. App. 1987), holding modified by Matter of Rubicon, Inc. , 95

- 0108 (La. App. 1 Cir. 2/1 4/96), 670 So.2d 475 (listing the IT Questions as five sepa rate questions); AR71:1. These IT Questions have since been incorporated into the Louisiana Revised Statutes. See La. R.S. § 30:2018(B). Case: 23-60234 Document: 142-1 Page: 24 Date Filed: 04/29/2024**LDEQ** explicitly performed the IT Question analysis for the
C ommonwealth permits and set forth twenty

- nine pages of reasoning in
support. See, e.g. , AR71:5

- 14 (analyzing the “concepts of alternative sites, alternative projects, and mitigation measures” in detail); AR71:15

- 20 (analyzing “the potential and real advers e environmental impacts . . . to ensure they are minimized to the maximum extent possible”); and AR71:20

- 28 (performing a “cost/benefit analysis” that addresses the “social and economic benefits of the proposed facility”). Much like its response to Sierra Club’s original **SIL** and **BACT** arguments, **LDEQ** answered each concern Sierra Club has raised with detailed, technical reasoning that demonstrates exactly why **LDEQ** chose to issue the preconstruction permits to Commonwealth. This certainly abides by the “rule o f reasonableness” inherent in the public trust doctrine. See Save Ourselves , 452 So.2d at 1157. While Sierra Club seems to argue that **LDEQ** must have gone beyond satisfaction of the **CAA** ’s requirements to also satisfy the public trust doctrine, no court has ever suggested as much. And even if Sierra Club were
correct, **LDEQ** did go beyond the **CAA** ’s requirements by carefully considering each of the IT Questions included in the Louisiana stat utes. See AR71. Contrary to Sierra Club’s assertion, **LDEQ** did not rely solely on minimum permitting requirements, but instead conducted a thorough air emissions analysis and found that the benefits of the Commonwealth facility were “major, significant, and tangible” so as to outweigh the de minimis projected emissions. AR71:28. U nless “the actual balance of costs and benefits that was struck was arbitrary or clearly gave insufficient weight to environmental protection,” this Court should not substitute its own judgment for that of **LDEQ**

. Save Ourselves , 452 So.2d at 1159. Sierra Club has not demonstrated that **LDEQ** ’s balancing was unreasonable or arbitrary, and therefore, we hold that **LDEQ** satisfied its public trustee duty when issuing the Commonwealth permits

. Case: 23-60234 Document: 142-1 Page: 25 Date Filed: 04/29/2024IV. Conclusion For the foregoing reason s , we **DENY** Sierra Club’s petition for review and affirm **LDEQ** ’s permitting decision. Case: 23-60234 Document: 142-1 Page: 26 Date Filed: 04/29/2024