The Volokh Conspiracy

Mostly law professors | Sometimes contrarian | Often libertarian | Always independent


Federal Court Rules Against CDC Transportation Mask Mandate

The decision holds that the CDC exceeded its legal authority. But it may be vulnerable to reversal on appeal.



On Monday, US federal district Judge Kathryn Kimball Mizelle issued a ruling holding that the Centers for Disease Control (CDC) mask mandate for airplanes, airports, and other transportation settings is illegal. At least for the moment, the federal government has announced that the mask mandate is no longer in effect, and most airlines have lifted it.

I am deeply opposed to the mask mandate, for reasons I summarized here. Nonetheless, I have doubts about the legal reasoning of today's opinion. If the Biden Administration decides to appeal, it's entirely possible the decision will be reversed.

The CDC claims that the mask mandate policy is authorized by 42 USC Section 264(a), the very same law that agency used to try to justify its nationwide eviction moratorium, which was invalidated by the Supreme Court in August. While I argued against the legality of the eviction moratorium from the very beginning, it seems to me that the transportation mask mandate rests on firmer grounds.

Section 264(a) gives the CDC the following powers:

The Surgeon General, with the approval of the [Secretary of Health and Human Services], is authorized to make and enforce such regulations as in his judgment are necessary to prevent the introduction, transmission, or spread of communicable diseases from foreign countries into the States or possessions, or from one State or possession into any other State or possession. For purposes of carrying out and enforcing such regulations, the Surgeon General may provide for such inspection, fumigation, disinfection, sanitation, pest extermination, destruction of animals or articles found to be so infected or contaminated as to be sources of dangerous infection to human beings, and other measures, as in his judgment may be necessary. [a later statute gives this authority to the CDC rather than the Surgeon General]

As described in my previous post on the mask mandate issue, the key difference between the eviction moratorium case and the present one is that the mask mandate doesn't have to rely on an ultra-broad interpretation of the catch-all "other measures" provision of the law. It can instead be defended as a "sanitation" measure. It seems to me that mandatory masking to prevent the spread of a respiratory virus at least plausibly fits within the meaning of "sanitation."

Judge Mizelle recognizes that this is the key issue in the case, and she relies on a narrower definition of sanitation. It's worth noting that the implication of her approach is that the CDC never had the power to impose a mask mandate. It's not a matter of the effectiveness of masking or the extent of the threat posed by the disease:

[S]anitation as used in the [Public Health Services Act] could have referred to active measures to cleanse something or to preserve the cleanliness of something. While the latter definition would appear to cover the Mask Mandate, the former definition would preclude it. Accordingly, the Court must determine which of the two senses is the best reading of the statute….

The context of § 264(a) indicates that "sanitation" and "other measures" refer to measures that clean something, not ones that keep something clean. Wearing a mask cleans nothing. At most it traps virus droplets. But it neither "sanitizes" the person wearing the mask nor "sanitizes" the conveyance….

Start with the immediate context. Sanitation travels in company with "inspection,
fumigation, disinfection, . . . pest extermination, [and] destruction." § 264(a). These terms.involve measures aimed at "identifying, isolating, and destroying the disease itself." Ala. Ass'n of Realtors, 141 S. Ct. at 2488. And though "sanitation" is "susceptible of multiple and wide-ranging meanings," it is "given more precise content by the neighboring words with which it is associated." United States v. Williams, 553 U.S. 285, 294 (2008). What these words have in common is that they involve identifying and eliminating known sources of disease. See Tiger Lily, LLC v. U.S. Dep't of Hous. & Urb. Dev. (Tiger Lily I), 992 F.3d 518, 523 (6th Cir. 2021) (summarizing subsection (a) as "government intrusions on property to sanitize and dispose of infected matter"). They do not maintain the status of being "disinfected" or "fumigated." Instead, they all change an object's status….

Customary usage at the time agrees. One method to assess the ordinary meaning of
a term is to search a database of naturally occurring language. A search returns the desired word as well as its context and, with a sufficient sample size, search results permit inferences on how a word was used. This method is known as corpus linguistics… The Court here searched the Corpus of Historical American English (COHAY) to find uses of "sanitation" between 1930 and 1944 [when Section 264 was enacted]. Of the 507 results, the most frequent usage of sanitation fit the primary sense described above: a positive act to make a thing or place clean. Common examples referred to sanitation in the context of garbage disposal, sewage and plumbing, or direct cleaning of a dirty or contaminated object. In contrast, by far the least common usage—hovering around 5% of the data set—was of sanitation as a measure to maintain a status of cleanliness, or as a barrier to keep something clean.

The above analysis is very thorough. But I remain skeptical. The broader definition of "sanitation" strikes me as more intuitive and more in accordance with ordinary usage than the narrow one. Among other things, the narrow definition would lead to some counterintuitive results. For example, if the CDC enacted a regulation barring defecation on the floor of a plane or train, that would not qualify as "sanitation" under Judge Mizelle's approach because it does not clean anything, but merely "keep[s] something clean" (in this case, the floor). Yet, I think, most ordinary people—both today and in 1944—would agree that a ban on defecating on the floor qualifies as a "sanitation" policy. And, as Judge Mizelle notes, courts are generally required to follow the ordinary meaning of words in a federal statute, unless there is some strong evidence to the contrary.

I think Judge Mizelle's best argument against the broad definition of "sanitation" is this one:

Recall that Congress listed "fumigation" and "disinfection" and "destruction" alongside "sanitation." § 264(a). If the government is correct that sanitation allows for the CDC's Mask Mandate because it promotes hygiene and prevents the spread of disease, then the remaining words in § 264(a), such as disinfection and fumigation are unnecessary. Every act necessary to prevent disease spread would be possible under sanitation. It would thus be impossible to give effect "to every clause and word of [the] statute," Moskal v. United States, 498 U.S. 103, 109-10 (1990), because these separate words would all be subsumed under the umbrella of "conventional 'sanitation' measure[s]"…. Such a reading renders most of the second sentence mere surplusage, an untenable result when other interpretations are available. See United States v. Butler, 297 U.S. 1, 65 (1936) ("These words cannot be meaningless, else they would not have been used."). Instead, sanitation more likely refers—consistent with its most common usage at the time—to acts that remove refuse or debris from an area or object, a reading that preserves independent meaning for the other terms in § 264(a).

The canon against redundancy is a longstanding rule of interpretation, and it does seem like the broad definition of "sanitation" might make "disinfection," destruction," and "fumigation" redundant. But I'm not sure that a plausible definition of  sanitation broad enough to include the mask order must necessarily be so broad as to render the other terms superfluous. "Sanitation" could be interpreted to refer to ordinary cleaning measures—both those that "remove refuse and debris" and those that help prevent it from arising in the first place (as with the rule against defecation!). By contrast, terms like "fumigation" and "disinfection" might refer to the use of chemical agents and other more sophisticated techniques to forestall (in the case of "fumigation") or eliminate (in the case of "disinfection") infection. "Destruction" also has a distinct meaning, of course, as even a broad definition of the other terms doesn't necessarily allow complete destruction of possibly dangerous articles.

There are lots of other issues in the opinion. For example, Judge Mizelle argues that the CDC violated the Administrative Procedure Act (APA) by failing to go through the "notice and comment" rule-making procedure. That argument strikes me as plausible; at the very least, it seems strange that such a consequential and sweeping rule can be in place for many months without going through normal rule-making procedures. But I will leave it to APA experts to address. Less persuasively, she claims the mask mandate amounts to a "conditional release" of would-be travelers, rather than a "sanitation" measure, and that 264(a) does not give the CDC any power to restrict the "liberty" of individuals.

At times, Judge Mizelle's opinion reads as if she is taking a kitchen sink approach to defending her ruling—throwing out every argument she can, good, bad, or indifferent. This strategy makes sense in high school debate, and perhaps for some legal briefs. But it isn't a good idea for judges ruling on a case, especially an important one.

That said, the judge does make some good points, most notably with respect to the canon against redundancy. I think she's probably wrong about the bottom line. But the ruling is far more defensible than critics on lawprof Twitter, and elsewhere, are willing to admit.

I would add that the ruling might have been influenced by the decline in the CDC's credibility caused by the agency's overreaching in cases like the eviction moratorium and Title 42 "public health" expulsions, and the increasingly incoherent nature of its position on masks, with the transportation mandate at odds with its recommendations in other settings.

Such factors, ideally, should not influence courts. But, at the margin, judges may be reluctant to defer to the supposed expertise of an agency with such a dubious track record.

Skepticism of the CDC is particularly evident in a section of the decision where Judge Mizelle concludes that the mask mandate violates the APA  by being "arbitrary and capricious" because it "provides little or no explanation for the CDC's choices," including the many exceptions to the mandate. The Judge pointedly rejects the argument that courts must simply defer to the agency's scientific judgement, emphasizing that the agency "needed to explain why it acted as it did."

At this point, it's unclear whether the Biden Administration will appeal the ruling. If they do, it's very possible the court of appeals will stay the trial court ruling, and ultimately reverse it. If so, we may not be free of the transportation mask mandate for long. But I, at least, plan to enjoy it while it lasts!

UPDATE: It's worth noting that this is not the only case challenging the transportation mask mandate. It's actually one of the less prominent ones (filed by a small nonprofit organization and two individual travelers. There are other lawsuits on this issue, as well, including one filed by 21 state governments, which raises some of the same issues, but also some that are different (such as claims that the mandate violates constitutional restrictions on federal "commandeering" of state governments).

UPDATE #2: I have made a few minor additions to this post.