Bench Memos

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Inventing Ambiguities in the Clean Air Act


The EPA made waves last week by releasing its ambitious new rule regulating existing sources of greenhouse gases. Amidst the reams of paper associated with the new regulation, the careful reader may have discerned this little gem of statutory interpretation on page 23 of the memorandum that lays out the agency’s legal analysis

The text of section 111(d) as presented in the U.S. Code, however, does not accurately reproduce the Section 112 Exclusion as enacted in the 1990 CAA Amendments. The correct statement of the Section 112 Exclusion – the one that was enacted by Congress and signed by the President, and which therefore is controlling – is found in the U.S. Statutes at Large. This text incorporates two versions of the Section 112 Exclusion, one passed by the U.S. House of Representatives and one passed by the U.S. Senate. The two versions were never reconciled, and both were enacted as part of the 1990 CAA Amendments. The two versions conflict with each other and thus render the Section 112 Exclusion ambiguous. Under these circumstances, the EPA may reasonably construe the Section 112 Exclusion to authorize the regulation of GHGs under section 111(d).

The purported conflict arises from the fact that the House and Senate passed similar (but textually different) amendments that operate on the same text of the U.S. Code. In essence, EPA is interpreting the House and Senate amendments (both of which are reflected in the text of the Statutes at Large at 109 Stat. 2399, 2467, 2574) in a way that causes them to conflict instead of interpreting them so they stand side-by-side. As Professor James Coleman has observed, EPA is echoing the arguments of Kate Konschnik, who is policy director for Harvard’s Environmental Law Program. This is the basis for EPA’s claim that the statute is ambiguous, and therefore that the agency’s interpretation should get Chevron deference.

Ambiguity is crucial to these greenhouse-gas regulations because, as EPA admits, the statute could be read to say “that the provision would not cover [greenhouse gases like carbon dioxide] because [greenhouse gases] are emitted from [electricity generating units] and [electricity generating units] are a source category regulated under section 112.”  If the provision doesn’t cover electricity-generating units, then EPA has no authority whatsoever to regulate greenhouse gases from power plants.

For reasons laid out by William Haun in a March 2013 paper, however, the asserted conflict is artificial because the content of the two amendments is readily reconcilable. One amendment prohibits EPA from regulating one category of source; the other amendment prohibits EPA from regulating a source listed under a different section. Even after both amendments, the word “or” remains in the statute. Thus, the two categories are nonexclusive and incapable of creating a conflict.

It is of course true that statutes should be interpreted so every word in the statute has a distinct meaning, but here, this principle suggests that there would only be ambiguity about whether a particular source fits into one category or the other. That’s entirely different from claiming, as EPA does, that because there are two amendments in the statute, it has the option to obey one and ignore the other.

Thankfully, it looks like EPA’s interpretation won’t go unchallenged. West Virginia’s attorney general, Patrick Morrisey, sent the EPA a letter making precisely this point. It’s too soon to know whether the EPA is receptive to the criticism, but I have a suspicion that this will end up in court sooner or later.


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