Chlorine Chemistry Council v. Envt'l Protection Agency

• Decision Date: 31 March 2000
• Docket Number: Nos. 98-1627,99-1053,99-1056,s. 98-1627
• Citation: 206 F.3d 1286
• Parties: (D.C. Cir. 2000) Chlorine Chemistry Council and Chemical Manufacturers Association, Petitioners v. Environmental Protection Agency, Respondent Natural Resources Defense Council, et al., Intervenors
• Court: U.S. Court of Appeals — District of Columbia Circuit

Page 1286

206 F.3d 1286 (D.C. Cir. 2000)

Chlorine Chemistry Council and Chemical Manufacturers Association, Petitioners v. Environmental Protection Agency, Respondent

Natural Resources Defense Council, et al., Intervenors

Nos. 98-1627, 99-1053, 99-1056

United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued February 11, 2000

Decided March 31, 2000

On Petitions for Review of an Order of the Environmental Protection Agency

Thomas Richichi argued the cause for petitioners Chlorine Chemistry Council, et al. and supporting intervenor Society of the Plastics Industry, Inc. With him on the briefs were Kathryn Y. Aspegren, David F. Zoll, Katherine L. Rhyne, Paul D. Clement, Richard S. Wasserstrom, Jerome H. Heckman, Peter L. de la Cruz and Komal J. Hershberg.

John F. Cooney and Brock Landry were on the brief for amicus curiae Public Health Scientists.

Karen L. Egbert, Attorney, U.S. Department of Justice, argued the cause for respondent. With her on the brief were Lois J. Schiffer, Assistant Attorney General, and Karen H. Clark, Attorney, U.S. Environmental Protection Agency. Christopher S. Vaden, Attorney, U.S. Department of Justice, entered an appearance.

Alan Charles Raul and David M. Levy were on the brief for amici curiae Congressman Tom Bliley.

Erik D. Olson was on the brief for intervenors Natural Resources Defense Council and Physicians for Social Responsibility.

Before: Silberman, Williams and Ginsburg, Circuit Judges.

Opinion for the Court filed by Circuit Judge Williams.

Williams, Circuit Judge:

The Safe Drinking Water Act ("SDWA" or the "Act") directs the Environmental Protection Agency to set standards for the regulation of covered drinking water contaminants. For each EPA sets a "maximum contaminant level goal" ("MCLG"), defined as "the level at which no known or anticipated adverse effects on the health of persons occur and which allows an adequate margin of safety." 42 U.S.C. S 300g-1(b)(4)(A). The MCLG is somewhat as pirational. After having set it, EPA is to promulgate an enforceable standard, known as a maximum contaminant level ("MCL"), which takes practical considerations into account while remaining "as close to the [MCLG] as is feasible."Id. S 300g-1(b)(4)(B).

In March 1998 EPA concluded that chloroform, a drinking water contaminant, exhibits a "nonlinear mode of carcinogenic action." Notice of Data Availability: National Primary Drinking Water Regulations: Disinfectants and Disinfection Byproducts, 63 Fed. Reg. 15,674, 15,686/1 (1998). In other words, exposures to chloroform below some threshold level pose no risk of cancer. But in promulgating the MCLG it retained the existing standard of zero, which was based on the previously held assumption that there was no safe threshold. Final Rule: National Primary Drinking Water Regulations: Disinfectants and Disinfection Byproducts, 63 Fed. Reg. 69,390, 69,398/3 (1998) ("Final Rule"). EPA justified its action on a variety of grounds, including an alleged need to consult the report of its Science Advisory Board ("SAB"), which would not be available until after the statutory deadline for rulemaking had expired. Petitioners, including the Chlorine Chemistry Council, a trade association comprised of chlorine and chlorine product manufacturers, petitioned this court for review, arguing that EPA violated its statutory mandate to use the "best available" evidence when implementing the provisions of the Safe Drinking Water Act. 42 U.S.C. § 300g-1(b)(3)(A). We agree.

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Chloroform, a "nonflammable, colorless liquid," Proposed Rule: National Primary Drinking Water Regulations: Disinfectants and Disinfection Byproducts, 59 Fed. Reg. 38,668, 38,694/2 (1994), is one of four compounds that together are classed as "Total Trihalomethanes" ("TTHMs"). These are byproducts of chlorination, the most widely used technique for ensuring the safety of drinking water. Chlorination plays a significant role in the control of microbial pathogens and in turn in the protection of public health; but on the basis of rodent tumor data the Agency has concluded that chloroform, a byproduct of this process, acts as a probable human carcinogen. Id. at 38,697/2.

On July 29, 1994 EPA issued a proposed rule on disinfectants and disinfection byproducts in water. This included a zero MCLG for chloroform, based on EPA's finding of an absence of data to suggest a threshold level below which there would be no potential carcinogenic effects. Id. The Agency's default method of inferring risk at exposure levels for which it has no adequate data is linear extrapolation from cancer incidence inferred at exposures for which it does have data.See EPA's Proposed Guidelines for Carcinogen Risk Assessment, 61 Fed. Reg. 17,960, 17,968/3 (1996). Thus, either if the evidence supports linearity, or if there is "insufficient" evidence of nonlinearity, EPA assumes that if a substance causes cancer at any exposure it will do so at every non-zero exposure (though with cancer incidence declining with exposure). But EPA acknowledges its authority "to establish nonzero MCLGs for carcinogens if the scientific evidence" indicates that a "safe threshold" exists. See Final Rule, 63 Fed. Reg. at 69,401/2. And petitioners here assume the validity of the linear default assumption.

In 1996 Congress amended the SDWA, enshrining in the statute a timetable previously set by EPA for rules relating to disinfectants and disinfection byproducts associated with water treatment. 42 U.S.C. § 300g-1(b)(2)(C); Proposed Rule: National Primary Drinking Water Regulations: Monitoring Requirements for Public Drinking Water Supplies, 59 Fed. Reg. 6332, 6361 (1994). The relevant deadline here was November 1998. In preparation for the necessary rulemaking EPA formed an advisory group in 1997 whose purpose was "to collect, share, and analyze new information and data, as well as to build consensus on the regulatory implications of this new information." Notice of Data Availability: National Primary Drinking Water Regulations: Interim Enhanced Surface Water Treatment Rule, 62 Fed. Reg. 59,486, 59,491/1 (1997).

On the basis of the committee's findings and recommendations, EPA in November 1997 published a Notice of Data Availability ("NODA"), 62 Fed. Reg. 59,388 (1997), and in 1998 it published a second NODA specific to chloroform, 63 Fed. Reg. 15,674 (1998). Among the findings it discussed were those arrived at by a panel of experts organized by the International Life Sciences Institute. The panel, whose work was subject to independent peer review and was convened under the auspices of the EPA, concluded on the basis of chloroform's mode of action that although it was "a likely carcinogen to humans above a certain dose range, [it was] unlikely to be carcinogenic below a certain dose range." Id. at 15,685/1. The panel recommended "the nonlinear [ ] or margin of exposure approach [as] the preferred approach to quantifying the cancer risk associated with chloroform exposure." Id. at 15,686/1.

EPA agreed. It said that "[a]lthough the precise mechanism of chloroform carcinogenicity is not established," nevertheless "the chloroform dose-response should be considered nonlinear." Id. at 15,685/3. Rather than operating through effects on DNA, which is consistent with linearity, chloroform evidently works through "cytotoxicity" (i.e., damage to the cells) followed by regenerative cell proliferation. Id. Employing the threshold approach that it found was entailed by chloroform's mode of action, EPA then calculated an MCLG of 600 parts per billion ("ppb"), based solely on carcinogenicity. Id. at 15,686/2. This level built in a 1000-fold margin of error in relation to the maximum safe dosage implied from the animal studies used by EPA. Id. But because even lower chlorine doses cause liver toxicity (a non-cancer effect), EPA proposed an MCLG of 300 ppb. Id.

When EPA came to promulgate its final rule in December 1998, however, its MCLG was again zero. Final Rule, 63 Fed. Reg. at 69,398/3. It stuck with 1994's zero level despite its explicit statement that it now "believe[d] that the underlying science for using a nonlinear extrapolation approach to evaluate the carcinogenic risk from chloroform is well founded." Id. at 69,401/1. It justified the action on the basis that "additional deliberations with the Agency's SAB on the analytical approach used" and on the underlying scientific evidence were needed "prior to departing from a long-held EPA policy." Id. at 69,399-69,401. It could not complete such additional deliberations by the November 1998 statutory deadline, and, moreover, the rulemaking would not affect the enforceable MCL for TTHMs.

After briefing on the petition for review at issue here, but before oral argument, EPA moved for a voluntary remand to consider the SAB report on chloroform that would soon be available. But EPA made no offer to vacate the rule; thus EPA's proposal would have left petitioners subject to a rule they claimed was invalid. We denied the motion.

On February 11, 2000, the day of oral argument, EPA released a draft report by the SAB on chloroform. See Draft, Chloroform Risk Assessment Review, February 10, 2000 (visited March 27, 2000) . The report concluded that chloroform exhibits a "cytotoxic" mode of action. Such a mode of action (unlike a "genotoxic" mechanism, which acts directly on a cell's DNA) involves no carcinogenic effects at low doses; thus a nonlinear approach is "scientifically reasonable." Id. at 17. After consideration of the draft SAB report, EPA stated that it "no longer believes that it should continue to defend its original decision," and moved that this court vacate the MCLG. Motion for Vacatur, at 2 (February 24, 2000).

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EPA in its motion to vacate concedes that "the discussion on standing at oral argument indicates that petitioners may indeed meet minimum requirements for standing," a necessary precursor to our providing any relief beyond the vacatur...