Opinion ID: 4020089
Heading Depth: 4
Heading Rank: 1

Heading: Identifying and Categorizing HAP Sources

Text: The EPA’s first task is to create HAP-source categories and subcategories. See 42 U.S.C. § 7412(c). The Act distinguishes “major” from “area” sources, defining the former as “any stationary source or group of stationary sources” that neighbor each other, share common control, and emit (or have the potential to emit) either ten tons per year or more of any single HAP or twenty-five tons per year or more 5 The EPA must keep the HAPs list current. See 42 U.S.C. § 7412(b)(2), (3). 6 of any HAP combination.6 Id. § 7412(a)(1). The latter are sources that do not emit enough HAPs to qualify as “major.” Id. § 7412(a)(2). Although the EPA must set stringent restrictions on major sources, it has discretion to set more lenient emissions caps on area sources. See id. § 7412(d)(5). Apart from the statutory distinction between major and area sources, the EPA has discretion to differentiate “among classes, types, and sizes of sources within a category or subcategory.” Id. § 7412(d)(1). Once the EPA finalizes HAPs-source categories and subcategories, the CAA mandates that it draw one final dividing line—between “new” sources and “existing” sources. See id. § 7412(d)(3). “New” sources are those “on which construction begins after EPA publishes emission standards,” Cement Kiln Recycling Coal. v. EPA, 255 F.3d 855, 858 (D.C. Cir. 2001); most of the others are “existing” sources, see 42 U.S.C. § 7412(a)(10). But if an existing source experiences either a physical change or a change in operation method and the change increases HAP emissions by more than a de minimis amount, the Act mandates that the source meet the standards set for new sources. See id. § 7412(a)(5), (g). b. Setting Emission Standards for Major Sources—the “MACT” Standard After the EPA identifies HAP-source categories and subcategories, it then sets emissions limits for each. See id. § 7412(d)(2). “[W]henever . . . feasible,” the caps must use numeric HAPs limits. Id. § 7412(h)(4). The size of the 6 The CAA defines “stationary source” as “any building, structure, facility, or installation which emits or may emit any air pollutant.” 42 U.S.C. § 7411(a)(3). 7 source—either “major” or “area”—dictates whether the EPA must set the numeric limit at the most stringent level that current technology allows or at the level set by “generally available control technologies.” Id. § 7412(d)(5). For major sources, the CAA directs the EPA to establish emissions caps that result in the “the maximum degree of reduction in emissions” that the EPA determines is “achievable.” Id. § 7412(d)(2). We refer to an emissions cap that reflects the current “maximum achievable control technology” as a “MACT” standard. See NRDC II, 529 F.3d at 1079. Setting a MACT standard is a two-step process. First, the EPA establishes a “MACT floor” for each category or subcategory. Sierra Club I, 353 F.3d at 980. The MACT floor ensures that all HAPs sources “at least clean up their emissions to the level that their best performing peers have shown can be achieved.” Id. For new sources—those built after promulgation of a HAPs limit, see 42 U.S.C. § 7412(a)(4)—the MACT floor cannot be less stringent than the emissions levels achieved by the best performing similar source. Id. § 7412(d)(3). For existing sources in categories or subcategories that have thirty or more sources, the MACT floor cannot be less stringent than the average emissions limits achieved by the best performing 12 per cent of existing sources in that category or subcategory. Id. § 7412(d)(3)(A). And for existing sources in categories or subcategories with fewer than thirty sources, the MACT floor cannot be less stringent than the average emissions achieved by the best performing five sources. Id. § 7412(d)(3)(B). When setting the MACT floor, the EPA considers only the performance of the cleanest sources in a category or subcategory; it does not take into account other factors, including the cost of putting a source in line with its better-performing counterparts. See Cement Kiln, 255 F.3d at 857-58 (citing Nat’l Lime Ass’n v. 8 EPA, 233 F.3d 625, 629 (D.C. Cir. 2000), as amended on denial of reh’g, No. 99-1325 (D.C. Cir. Feb. 14, 2001)). Second, the EPA must determine whether current technology makes it possible for a source to perform even better than the best performing similar source or sources. In other words, the CAA directs the EPA to consider whether it should set a “beyond-the-floor” MACT standard. Nat’l Lime Ass’n, 233 F.3d at 629. In determining whether a beyond-thefloor standard is “achievable,” the Agency must consider additional factors like “the cost of achieving such emission reduction,” “any non-air quality health and environmental impacts” and “energy requirements.” 42 U.S.C. § 7412(d)(2). It has broad discretion in its determination. See id.; cf. Nat’l Ass’n of Clean Water Agencies v. EPA (NACWA), 734 F.3d 1115, 1157 (D.C. Cir. 2013) (noting, in section 7429 case, that “Congress gave EPA broad discretion in considering whether to go beyond-the-floor”). c. Setting Emission Standards for Area Sources—the “GACT” Standard Although the EPA must cap HAP emissions from major sources at the “maximum degree of reduction,” see 42 U.S.C. § 7412(d)(2), it has discretion to set less stringent caps on emissions from area sources. Indeed, the EPA need not list categories of area sources at all unless: (A) it finds that the sources in that category or subcategory “present[] a threat of adverse effects” to the environment or human health, see id. § 7412(c)(1), (3); or (B) control of a particular area source category or subcategory is necessary to ensure that sources accounting for at least 90 per cent of the aggregate emissions of the thirty HAPs the EPA believes “present the greatest threat to public health in the largest number of urban areas” 9 are subject to CAA control, id. § 7412(c)(3), (k)(3)(B). If it finds that controlling emissions from a particular area source subcategory is necessary to achieve a 90 per cent reduction in the aggregate emissions of any of seven CAA-enumerated HAPs, section 7412(c)(6) requires the Agency to impose MACT caps on that subcategory. See id. § 7412(c)(6). With the exception of section 7412(c)(6)’s MACT- standard requirement, the EPA need not cap emissions from area sources at the MACT level. Instead, it may set more lenient emissions limits based on “generally available control technologies.” Id. § 7412(d)(5). We refer to these caps as GACT standards. The Act provides no guidance for setting GACT standards but the legislative history of the 1990 CAA Amendments describes GACT “as methods, practices and techniques [that] are commercially available and appropriate for application by the sources in the category considering economic impacts and the technical capabilities of the firms to operate and maintain the emissions control systems.” S. REP. NO. 101-228, at 171 (1989). According to the EPA, it can and will consider the following in setting a GACT standard:  “costs and economic impacts . . . , which [are] particularly important when developing regulations for source categories that may have many small businesses . . . ”;  “the control technologies and management practices that are generally available to the area sources in the source category”;  “the standards applicable to major sources in the analogous source category to determine if 10 the control technologies and management practices are transferable and generally available to area sources”; and  “technologies and practices at area and major sources in similar categories to determine whether such technologies and practices could be considered generally available for the area source categories at issue.” 2011 Area Boilers Rule, 76 Fed. Reg. at 15,556. And, unlike the EPA’s duty to consider a beyond-the-floor MACT standard, it need not consider a more stringent GACT standard. d. Work-Practice and Management-Practice Standards Although the CAA requires numeric emission standards where possible, the EPA can “promulgate a design, equipment, work practice, or operational standard, or combination thereof” if it determines that a numeric limit is “not feasible.” 42 U.S.C. § 7412(h)(1). In other words, the EPA can require that all sources in a given category or subcategory take a certain action (e.g., conduct a periodic tune-up) or install certain emissions-control technology (e.g., install a fabric filter). Although the EPA has discretion to impose a work-practice standard, the Act limits it by defining the operative phrase “not feasible” narrowly to mean: (A) a hazardous air pollutant or pollutants cannot be emitted through a conveyance designed and constructed to emit or capture such pollutant, or that any requirement for, or use of, such a conveyance would be inconsistent with any Federal, State or local law, or 11 (B) the application of measurement methodology to a particular class of sources is not practicable due to technological and economic limitations. Id. § 7412(h)(2). Similarly, for area sources, the EPA can impose a “management-practice standard” in lieu of a numeric GACT standard. See id. § 7412(d)(5). A management-practice GACT standard is like a work-practice MACT standard in all ways but one—the EPA need not consider feasibility when setting management-practice standards. Compare id. § 7412(d)(2), with id. § 7412(d)(5).