On Petitions for Review of an Order of the Environmental Protection Agency
Before: Sentelle, Henderson and Garland, Circuit
This action challenges the Emission Guidelines for Existing Small Municipal Waste Combustion Units, 65 Fed. Reg. 76,378 (Dec. 6, 2000), and the New Source Performance Standards for New Small Municipal Waste Combustion Units, 65 Fed. Reg. 76,350 (Dec. 6, 2000), promulgated by the United States Environmental Protection Agency (EPA, Agency) pursuant to § 129 of the Clean Air Act (CAA), 42 U.S.C. § 7429.*fn1 The petitioners include three members of the municipal waste combustor industry (Industry Petitioners): Northeast Maryland Waste Disposal Authority (Northeast Maryland), which operates four municipal waste combustor (MWC) units in Harford County, Maryland;*fn2 Dutchess County Resource Recovery Agency, which operates two MWC units at a facility in Poughkeepsie, New York and Islip Resource Recovery Agency, which operates two MWC units at a facility in Islip, New York. The petitioners also include two environmental organizations: the New York Public Interest Research Group (NYPIRG) and the Sierra Club (collectively identified as Sierra Club). For the reasons set out below, we grant the petitions in part and deny the petitions in part.
The challenged rulemaking is now in its third decade. In 1987 EPA issued an advance notice of a rulemaking to regulate pollutants produced by MWC emissions pursuant to § 111 of the CAA, 42 U.S.C. § 7411, which requires EPA to develop emission standards generally for each category of pollutant EPA determines "causes, or contributes significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare," 42 U.S.C. § 7411(b)(1)(A). See Assessment of Municipal Waste Combustor Emissions Under the Clean Air Act, 52 Fed. Reg. 25,399, 25,399 (July 7, 1987). In 1989 EPA issued proposed emission regulations imposing limits on the MWC emission levels for specific pollutants, based on the level of emissions achievable with the best pollution control technology, but did not prescribe specific control technologies to be used to achieve the limits. See Standards of Performance for New Stationary Sources; Municipal Waste Combustors, 54 Fed. Reg. 52,251 (Dec. 20, 1989).
In 1990 the Congress enacted CAA § 129, 42 U.S.C. § 7429, which expressly requires EPA to establish specific standards for each "solid waste incineration unit."*fn3 The standards must "reflect the maximum degree of reduction in emissions of air pollutants listed under section (a)(4) that [EPA], taking into consideration the cost of achieving such emission reduction, and any non-air quality health and environmental impacts and energy requirements, determines is achievable for new or existing units in each category." Id. § 7429(a)(2).*fn4 These standards are known as "maximum achievable control technology" or "MACT" standards. The statute limits EPA's discretion to determine the stringency of MACT standards. MACT standards must be at least as stringent as the MACT floor set for each pollutant. The MACT floor for new units is defined as "the emissions control ... achieved in practice by the best controlled similar unit." Id. The MACT floor for existing units is defined as "the average emissions limitation achieved by the best performing 12 percent of units in the category." Id. The statute mandates two "categories" within both existing and new units (defined in terms of combustion capacity), with different deadlines for promulgating standards, id. § 7429(a)(1)(B)-(C), and further provides that EPA "may distinguish among classes, types, ... and sizes of units within a category in establishing [MACT] standards," id. § 7429(a)(2).
In 1994 EPA proposed new standards governing MWC units pursuant to § 129. See Standards of Performance for New Stationary Sources: Municipal Waste Combustors, 59 Fed. Reg. 48,198 (Sept. 20, 1994). The Agency proposed distinct sets of standards for new and for existing sources, as the statute contemplates, and broke down both source types into two categories based on the aggregate plant capacity for municipal solid waste (MSW), that is, based on the sum of the maximum amount of waste each MWC unit located at a particular site is designed to combust daily. Thus, within both existing and new source types, EPA created a large unit category -- consisting of units located at plants with an aggregate MSW capacity greater than 250 tons per day (tpd) -- and a small unit category -- consisting of units located at plants with an aggregate MSW capacity of 250 tpd or less (but greater than 35 tpd).
In 1995 EPA issued its final standards, which generally tracked the proposed ones. See Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Municipal Waste Combustors, 60 Fed. Reg. 65,387 (Dec. 19, 1995) (1995 Rule). Two MWC facility operators petitioned this court to review the 1995 Rule, asserting that EPA violated § 129's unambiguous language when it defined large and small units based on the aggregate MSW combustion capacity of the plant at which a MWC unit is located rather than on the combustion capacity of the individual MWC unit itself. We agreed with the petitioners and vacated the standards, holding that "the EPA's use of aggregate plant MSW capacity rather than unit MSW capacity in the 1995 standards to create categories of MWC units for MACT purposes violates the plain meaning of section 129 and exceeds the EPA's statutory authority." Davis County Solid Waste Mgmt. v. EPA, 101 F.3d 1395, 1411 (D.C. Cir. 1996). Subsequently, on EPA's motion for rehearing, the court modified the remedy to vacate only the small unit standards because it concluded "the Davis opinion will not meaningfully alter the [new source performance standards] or the emission guidelines applicable to [existing] large units and that vacating the large unit standards will have a significant deleterious effect." Davis County Solid Waste Mgmt. v. EPA, 108 F.3d 1454, 1460 (D.C. Cir. 1997) (rehearing).
In August 1999 EPA proposed new standards for the category of small MWC units, which it defined as units "with a combustion design capacity of 35 to 250 tons per day." Emission Guidelines for Existing Stationary Sources: Small Municipal Waste Combustion Units, 64 Fed. Reg. 47,234, 47,236 (Aug. 30, 1999).*fn5 Existing small units were further divided into three subcategories according to type and aggregate plant capacity: Class A, consisting of "nonrefractorytype small MWC units located at plants with an aggregate plant capacity greater than 250 tons per day of MSW"; Class B, consisting of "refractory-type small MWC units located at plants with an aggregate plant capacity greater than 250 tons per day of MSW";*fn6 and Class C, consisting of all "small MWC units located at plants with an aggregate plant capacity less than or equal to 250 tons per day of MSW." Id. New small units were divided into only two subcategories, strictly by aggregate plant capacity: Class I, consisting of small units located at plants with aggregate plant capacities greater than 250 tons of MSW per day, and Class II, consisting of small units located at plants with aggregate plant capacities less than or equal to 250 tons of MSW per day. New Source Performance Standards for New Small Municipal Waste Combustion Units, 64 Fed. Reg. 47,276, 47,279 (Aug. 30, 1999).
Following comment and hearing, in December 2000 EPA issued its final standards, which established subcategories by aggregate plant capacity alone both for existing units, 65 Fed. Reg. 76,378, and for new units, 65 Fed. Reg. 76,350, (collectively, the 2000 Rule). For both existing and new units, Class I consists of small MWC units located at plants with aggregate plant capacities greater than 250 tons of MSW per day, while Class II comprises small MWC units located at plants with aggregate plant capacities equal to or less than 250 tons of MSW per day. 65 Fed. Reg. at 76,379 (existing small units); 65 Fed. Reg. at 76,351 (new small units). Within each subcategory EPA calculated a MACT floor for each pollutant and set a standard at or beyond the floor.
On February 2, 2001 Waste Energy Partners, together with other parties to the administrative proceeding, petitioned EPA for reconsideration, and all Industry Petitioners filed petitions for review of the final standards with the court. On February 5, 2001 NYPIRG filed a petition for administrative reconsideration, and on February 6, 2001 Sierra Club filed a petition for judicial review of the standards. EPA denied WEP's petition for reconsideration on August 7, 2002, J.A. 2317, and denied NYPIRG's petition on August 14, 2002, J.A. 2319.
Under § 307(d)(9) of the CAA, the court reviews EPA action as follows:
In the case of review of any action of the Administrator to which this subsection applies, the court may reverse any such action found to be --
(A) arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law;
(B) contrary to constitutional right, power, privilege, or immunity;
(C) in excess of statutory jurisdiction, authority, or limitations, or short of statutory right; or
(D) without observance of procedure required by law, if (i) such failure to observe such procedure is arbitrary or capricious, (ii) the requirement of paragraph (7)(B) has been met, and (iii) the condition of the last sentence of paragraph (8) is met.*fn7
We begin with the challenges raised by Industry Petitioners. Each of these petitioners owns and operates small MWC units -- i.e., units with capacities equal to or less than 250 tpd. Because each of these small MWC units is located at a plant with multiple units, the aggregate capacity of which exceeds 250 tpd, each is classified as a Class I facility under the 2000 Rule. Industry Petitioners challenge the emission limits set by the 2000 Rule for existing units on both substantive and procedural grounds. We consider those challenges below.
1. Substantive Challenges
Industry Petitioners raise two substantive challenges to the 2000 Rule. First, they contend that § 129(a)(2) of the Clean Air Act requires EPA to establish one MACT floor for all existing units within the small unit category, and that the Agency therefore exceeded its statutory authority by establishing different MACT floors for subcategories of units (i.e., Class I and Class II units). Second, Industry Petitioners argue that, even if EPA may subcategorize when setting MACT floors, the Act does not permit it to do so on the basis of aggregate plant capacity. The consequence of this unlawful subcategorization, they protest, is that their Class I units are subjected to more stringent standards than they would be if MACT floors were instead calculated on a category-wide basis.*fn8
Both Industry Petitioners and EPA contend that our opinion in Davis County Solid Waste Management v. EPA, 101 F.3d 1395 (D.C. Cir. 1996), governs the question of subcategorization authority -- although each side draws a different lesson from that case. Accordingly, we begin with a brief recap of Davis.
As noted above, EPA promulgated an earlier round of standards to regulate municipal waste combustion in 1995. See 60 Fed. Reg. 65,387. Unlike the 2000 Rule, which applies only to the category of small (250 tpd or less) MWC units and which subcategorizes that category based on aggregate plant capacity, the 1995 Rule categorized units based on aggregate plant capacity. As a consequence, the 1995 Rule grouped a number of small MWC units with individual capacities of less than 250 tpd into the same category as large units with individual capacities greater than 250 tpd, because those small units were located at facilities with aggregate capacities greater than 250 tpd. Id. In Davis, we found the 1995 Rule unlawful, concluding that the Clean Air Act created two separate "categories of MWC units based on unit capacity, units with unit MSW capacities above 250 tons/day and units with unit MSW capacities of 250 tons/day or less." 101 F.3d at 1410. In support, we relied on the fact that § 129(a)(1) imposed "different dates by which the standards for large and small MWC units must be promulgated," and that it therefore "separately define[d] these two types of MWC units." Id. at 1403.*fn9
Although the only question in Davis was the lawfulness of including both large and small units within the same category, the opinion contains dicta upon which each side has seized regarding the question of subcategorization. EPA focuses on the Davis court's suggestion -- repeated four times in the opinion -- that the Agency may "exercise[ ] its discretion to distinguish among units within a category and create[ ] subcategories of small units, for which it can then calculate MACT floors and standards separately." Id. at 1408; see also id. at 1404-05, 1405 n.11, 1409 n.12, 1411. EPA reads this statement as advising that, while the Agency is obligated to categorize MWCs based on unit capacity, it remains free to subcategorize the small unit category based on other factors. See Respondent's Br. at 27; see also 64 Fed. Reg. at 47,237 (quoting passage from Davis and concluding that the court's decision allows EPA to exercise its discretion to set MACT floors based on subcategories of small units). In opposition, Industry Petitioners maintain -- "[w]ith all due respect" to the Davis court -- that the above-quoted material "is directly at odds with" other sentences in the same opinion. Reply Br. at 5. In particular, petitioners rely on Davis ' statement that, "in order to promulgate emissions standards, the EPA must first calculate the MACT floors, and the EPA cannot calculate the MACT floors until it has studied the emissions levels of all units in the relevant category," as barring EPA from calculating MACT floors based on anything other than a category-wide basis. Davis, 101 F.3d at 1404.
Given that Davis -- which did not involve subcategorization within a category at all, but rather an attempt by the Agency to collapse two statutory categories into one -- contains no holding on the subcategorization question at issue here, we see little to be gained by striving to reconcile its dicta. Instead, we look directly to the relevant statutory language in order to determine whether EPA's action was authorized. That language is contained in § ...