 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued March 12, 2019                  Decided June 11, 2019

                        No. 18-1116

      UNITED STEEL, PAPER AND FORESTRY, RUBBER,
                  MANUFACTURING,
   ENERGY, ALLIED INDUSTRIAL AND SERVICE WORKERS
                INTERNATIONAL UNION,
  AFL-CIO-CLC AND UNITED MINE WORKERS OF AMERICA
                INTERNATIONAL UNION,
                     PETITIONERS

                              v.

      MINE SAFETY AND HEALTH ADMINISTRATION AND
      R. ALEXANDER ACOSTA, SECRETARY OF LABOR,
         UNITED STATES DEPARTMENT OF LABOR,
                     RESPONDENTS


          On Petition for Review of a Final Rule of
          the Mine Safety & Health Administration


     Laura Karr argued the cause for the petitioner United
Mine Workers. Susan J. Eckert argued the cause for the
petitioner United Steelworkers. Joseph M. Santarella, Jr. and
Andrew D. Roth were with them on brief.

    Emily Toler Scott, Attorney, Mine Safety & Health
Administration, argued the cause for the respondents. Ali A.
Beydoun, Counsel, Appellate Litigation, was with her on brief.
                               2

    Before: HENDERSON, ROGERS and KATSAS, Circuit
Judges.

    Opinion for the Court filed by Circuit Judge HENDERSON.

    Opinion concurring in part and dissenting in part filed by
Circuit Judge KATSAS.

      KAREN LECRAFT HENDERSON, Circuit Judge: The Mine
Safety and Health Administration (MSHA), housed in the
United States Department of Labor (Labor), sets health and
safety standards for mine operations. Its regulatory authority
is subject to a unique limitation: “[n]o mandatory health or
safety standard . . . shall reduce the protection afforded miners
by an existing mandatory health or safety standard.” 30
U.S.C. § 811(a)(9). The no-less-protection standard occupies
center stage in the case before us. In 2017, MSHA
promulgated a safety standard that requires mine operators to
examine all areas before miners begin work and to record all
“conditions that may adversely affect safety or health”
discovered during the examination. Examinations of Working
Places in Metal and Nonmetal Mines, 82 Fed. Reg. 7680, 7682
(Jan. 23, 2017) (2017 Standard). Fourteen months later,
however, MSHA amended the requirements, allowing
examinations to occur before or as miners begin work and
allowing mine operators to exclude from their records adverse
conditions that are promptly corrected. Examinations of
Working Places in Metal and Nonmetal Mines, 83 Fed. Reg.
15,055 (Apr. 9, 2018) (codified at 30 C.F.R. §§ 56.18002(a)–
(c), 57.18002(a)–(c)) (2018 Amendment). We are called upon
to decide whether MSHA explained adequately how the
amendments to the 2017 Standard comply with the no-less-
protection standard.
                               3
                      I. BACKGROUND

     The Federal Mine Safety and Health Act of 1977, Pub. L.
No. 91-173, 83 Stat. 742 (codified as amended at 30 U.S.C.
§§ 801 et seq.) (Mine Act), directs the Labor Secretary to
“develop, promulgate, and revise as may be appropriate,
improved mandatory health or safety standards for the
protection of life and prevention of injuries in coal or other
mines.” 30 U.S.C. § 811(a). The Secretary discharges his
Mine Act responsibilities through MSHA. The Mine Act
includes a no-less-protection standard, which provides that
“[n]o mandatory health or safety standard . . . shall reduce the
protection afforded miners by an existing mandatory health or
safety standard.” Id. § 811(a)(9). This unusual limitation
“expressly mandates that no reductions in the level of safety
below existing levels be permitted, regardless of the benefits
accruing to improved efficiency.” United Mine Workers of
Am., Int’l Union v. Dole, 870 F.2d 662, 666 (D.C. Cir. 1989).

    MSHA has for decades required examinations of mine
workplaces and imposed recordkeeping requirements on mine
operators.   From 1979 to 2017, MSHA required “[a]
competent person designated by the operator” to “examine
each working place at least once each shift for conditions which
may adversely affect safety or health.” 30 C.F.R. § 56.18-2(a)
(1980); see also id. § 57.18-2(a) (same requirements for
underground mines). The examination could occur anytime
during the shift. Id. The standard also mandated that
operators keep “[a] record that [] examinations were
conducted.” Id. § 56.18-2(b); see also id. § 57.18-2(b)
(underground mines).

    In 2017, MSHA decided to impose more stringent
requirements. Examinations of Working Places in Metal and
Nonmetal Mines, 82 Fed. Reg. at 7680–81. It adopted a new
                               4
standard for workplace examinations: “[a] competent person
designated by the operator shall examine each working place
at least once each shift before miners begin work in that place,
for conditions that may adversely affect safety or health.” 30
C.F.R. § 56.18002(a) (2017) (emphasis added) (2017
Standard); see also id. § 57.18002(a) (underground mines). It
also added more detailed recordkeeping requirements,
demanding for the first time that a record of an examination
include (as relevant here): a “description of each condition
found that may adversely affect the safety or health of miners.”
Id. § 56.18002(b); see also id. § 57.18002(b) (underground
mines). The 2017 Standard was originally slated to take effect
on May 23, 2017. MSHA twice delayed the effective date.
See Examinations of Working Places in Metal and Nonmetal
Mines, 82 Fed. Reg. 15,173 (March 27, 2017); Examinations
of Working Places in Metal and Nonmetal Mines, 82 Fed. Reg.
23,139 (May 22, 2017).          After a three-day period of
effectiveness in October 2017, MSHA temporarily withdrew
the 2017 Standard and delayed its effective date for a third
time. See Examinations of Working Places in Metal and
Nonmetal Mines, 82 Fed. Reg. 46,411 (Oct. 5, 2017).

     In April 2018, MSHA promulgated a final rule amending
the requirements of the 2017 Standard. Examinations of
Working Places in Metal and Nonmetal Mines, 83 Fed. Reg. at
15,055 (2018 Amendment). Under the 2018 Amendment, a
competent person must “examine each working place at least
once each shift before work begins or as miners begin work in
that place[] for conditions that may adversely affect safety or
health.” 30 C.F.R. § 56.18002(a) (emphasis added); see also
id. § 57.18002(a) (underground mines). Unlike the 2017
Standard, then, the 2018 Amendment gives mine operators the
option to conduct examinations as miners begin work in an
area.    Id.    The 2018 Amendment also modifies the
recordkeeping requirement to mandate that a “record shall
                              5
contain the . . . description of each condition found that may
adversely affect the safety or health of miners and is not
corrected promptly.” Id. § 56.18002(b) (emphasis added); see
also id. § 57.18002(b) (underground mines). The new
language allows a mine operator to omit from its records
promptly corrected adverse conditions. Id. The 2018
Amendment went into effect on June 2, 2018.

     Petitioners the United Steel, Paper and Forestry, Rubber,
Manufacturing, Energy, Allied Industrial and Service Workers
International Union, AFL-CIO/CLC, and the United Mine
Workers of America International Union filed a timely petition
for review of the 2018 Amendment. They claim that the 2018
Amendment violates both the Mine Act’s no-less-protection
standard, 30 U.S.C. § 811(a)(9), and the Administrative
Procedure Act, 5 U.S.C. §§ 701 et seq.

                        II. ANALYSIS

     The Mine Act requires MSHA to “state the basis for its
conclusion” that a new health or safety standard satisfies the
no-less-protection standard. Nat’l Min. Ass’n v. MSHA, 116
F.3d 520, 536 (D.C. Cir. 1997) (per curiam) (no-less-protection
standard “requires the agency to state the basis for its
conclusion that the [standard] has been satisfied”). The
statement is subject to review under the Administrative
Procedure Act and must manifest that MSHA engaged in
reasoned decisionmaking. See id.; see also Rosebud Mining
Co. & Parkwood Res., Inc. v. MSHA, 827 F.3d 1090, 1101
(D.C. Cir. 2016) (MSHA action reviewed under
Administrative Procedure Act). Our review “is, as always,
‘highly deferential and presumes the validity of agency
action.’” Nat’l Min. Ass’n, 116 F.3d at 536 (quoting Dole, 870
F.2d at 666).
                                 6
               A. EXAMINATION REQUIREMENT

     The petitioners first claim that MSHA failed to explain
adequately how the 2018 Amendment’s examination
requirement complies with the no-less-protection standard.
As noted, the 2017 Standard required examinations to occur
before miners begin work in an area. 30 C.F.R. § 56.18002(a)
(2017); see also id. § 57.18002(a). By contrast, the 2018
Amendment “allows miners to enter a working place at the
same time a competent person examines for adverse
conditions.” Examinations of Working Places in Metal and
Nonmetal Mines, 83 Fed. Reg. at 15,058. On its face, this
change appears to increase miners’ exposure to health and
safety risks. As the Labor Secretary has observed, a careful
person does not check the sturdiness of his ladder after
climbing half the rungs nor does a careful mine operator check
the safety of an area while allowing miners to work there. See
Secretary of Labor’s Response Brief at 18–19, Nat’l Mining
Ass’n et al. v. MSHA, No. 17-11207 (11th Cir. July 19, 2017)
(invoking ladder analogy for mine safety argument). Even so,
MSHA claims the no-less-protection standard is satisfied
because under the 2018 Amendment, as under the 2017
Standard, adverse conditions will be “identified and miner
notification provided before miners are potentially exposed to
the conditions.” 1 Examinations of Working Places in Metal
and Nonmetal Mines, 83 Fed. Reg. at 15,058.


    1
        MSHA contends on brief to us that the new examination
requirement creates additional safety benefits by reducing “the risk
that, between the time of the examination and the time miners begin
work, conditions will have changed and created new or different
hazards.” The contention does not appear in the administrative
record and so we do not consider it. See PG&E Gas Transmission,
Nw. Corp. v. FERC, 315 F.3d 383, 388 (D.C. Cir. 2003) (“[T]his
Court cannot consider . . . post hoc justifications” and “may only
                                 7
     The problem with this explanation is that the 2018
Amendment does not allow for notification before exposure.
Its notification provisions state: “[t]he operator shall promptly
notify miners in any affected areas of any conditions found that
may adversely affect safety or health” and “[c]onditions noted
by the person conducting the examination that may present an
imminent danger shall be brought to the immediate attention of
the operator.” 30 C.F.R. § 56.18002(a)(1)–(2). These
provisions require notification as soon as an adverse condition
is discovered. Id. Nowhere do they require notification
before miners are exposed. See id. Because the 2018
Amendment allows miners to work in an area before the
examination is completed, there is the likelihood that miners
may be exposed to an adverse condition before it is discovered.
Id. § 56.18002(a) (“A competent person . . . shall examine
each working place at least once each shift before work begins
or as miners begin work in that place.”). MSHA’s attempt to
explain how the examination requirement complies with the
no-less-protection standard relies on a non-existent
notification-before-exposure duty and is therefore arbitrary and
capricious. 2 Motor Vehicle Mfrs. Ass’n of U.S., Inc. v. State


consider the grounds on which the [agency] actually relied in making
its decision.”).
    2
       It is no answer to say, as MSHA does, that the preamble to the
2018 Amendment expresses MSHA’s intention that miners receive
notification before being exposed to adverse conditions.
Examinations of Working Places in Metal and Nonmetal Mines, 83
Fed. Reg. at 15,058 (“MSHA intends for adverse conditions to be
identified and miner notification provided before miners are
potentially exposed to the conditions.”). Mine operators must
comply with the notification requirements of the 2018 Amendment,
not MSHA’s statements “from the preamble, which itself lacks the
force and effect of law.” See Saint Francis Med. Ctr. v. Azar, 894
F.3d 290, 297 (D.C. Cir. 2018).
                                8
Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43 (1983) (action is
arbitrary and capricious “if the agency has . . . offered an
explanation . . . so implausible that it could not be ascribed to
a difference in view or the product of agency expertise”).

     The explanation is arbitrary and capricious for a second
reason: it cannot be reconciled with factual findings that
MSHA made in support of the 2017 Standard. An agency is
generally free to change positions so long as it can “show that
there are good reasons for the new policy,” not “that the reasons
for the new policy are better than the reasons for the old one.”
FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515 (2009).
This flexibility has limits. If the “new policy rests upon
factual findings that contradict those which underlay its prior
policy,” the agency must offer “a reasoned explanation . . . for
disregarding facts and circumstances that underlay . . . the prior
policy.” Id. at 515–16. In promulgating the 2017 Standard,
MSHA found that “[i]f the examination is performed after
miners begin work, miners may be exposed to conditions that
may adversely affect their safety and health.” Examinations
of Working Places in Metal and Nonmetal Mines, 82 Fed. Reg.
at 7689. For that reason, MSHA explained, the 2017 Standard
“requires that a competent person conduct an examination
before work begins so that conditions that may adversely affect
miners’ safety and health are identified before they begin work
and are potentially exposed.” Id. at 7683 (emphasis added).
MSHA took a new contrary-to-fact position in the 2018
Amendment: miners can begin work before the required
examination is completed without being exposed to adverse
conditions. Examinations of Working Places in Metal and
Nonmetal Mines, 83 Fed. Reg. at 15,058. It gave no
explanation for the change.

    There is another unexplained departure. From 1979 to
2017, MSHA’s safety standard allowed operators to conduct an
                               9
examination anytime during a shift. See 30 C.F.R. § 56.18-
2(a) (1980); see also id. § 57.18-2(a) (underground mines).
This flexibility, in MSHA’s “experience,” created “a
significant degree of variability in how safety programs are
operationalized.” Examinations of Working Places in Metal
and Nonmetal Mines, 82 Fed. Reg. at 7689. MSHA
introduced the 2017 Standard, in part, to “reduce the variability
in how operators conduct examinations of working places and
thereby improve miners’ safety and health.” Id. The 2018
Amendment reintroduced that very same variability by
allowing examinations to occur before or while miners begin
work.      E.g., 30 C.F.R. § 56.18002(a).       Despite citing
increased flexibility as a boon for mine operators, MSHA
completely ignored its previous finding that increased
flexibility (read: variability) does not improve miner safety.
Examinations of Working Places in Metal and Nonmetal
Mines, 83 Fed. Reg. at 15,058. For these reasons, we agree
with the petitioners that MSHA has failed to explain adequately
how the 2018 Amendment’s examination requirement
complies with the statutory no-less-protection standard.

            B. RECORDKEEPING REQUIREMENT

     The petitioners next argue that MSHA failed to provide a
reasoned explanation why the recordkeeping requirement of
the 2018 Amendment satisfies the no-less-protection standard.
In the preamble to the 2017 Standard, MSHA determined that
“recording all adverse conditions, even those that are
corrected immediately, will be useful as a means of identifying
trends,” which “should help inform mine management
regarding areas or subjects that may benefit from increased
safety emphasis.” See Examinations of Working Places in
Metal and Nonmetal Mines, 82 Fed. Reg. at 7686 (emphasis
added). MSHA acknowledged this determination in the
preamble to the 2018 Amendment. Examinations of Working
                              10
Places in Metal and Nonmetal Mines, 83 Fed. Reg. at 15,059.
It nonetheless concluded that “a recording exception for
adverse conditions that are corrected promptly,” like the one
created by the 2018 Amendment, “will yield as much or more
in safety benefits, because it encourages prompt correction of
adverse conditions.” Id.

     MSHA’s unsupported explanation does not withstand
scrutiny.     An agency must “articulate a satisfactory
explanation for its action including a ‘rational connection
between the facts found and the choice made.’” State Farm
Mut. Auto. Ins. Co., 463 U.S. at 43 (quoting Burlington Truck
Lines v. United States, 371 U.S. 156, 168 (1962)). MSHA
recognized that the recordkeeping requirements of both the
2017 Standard and the 2018 Amendment provide safety
benefits. Examinations of Working Places in Metal and
Nonmetal Mines, 83 Fed. Reg. at 15,059. Under the no-less-
protection standard, then, MSHA’s burden was to explain why
the benefits of the 2018 Amendment equal or exceed those of
the 2017 Standard. See 30 U.S.C. § 811(a)(9). MSHA
instead declared, without further elaboration, that the 2018
Amendment “will yield as much or more in safety benefits,
because it encourages prompt correction of adverse
conditions.” Examinations of Working Places in Metal and
Nonmetal Mines, 83 Fed. Reg. at 15,059. This reasoning—the
2018 Amendment will yield better safety protection by
incentivizing mine operators to promptly correct adverse
conditions—is, at best, specious. The 2017 Standard already
requires mine operators to “promptly initiate appropriate action
to    correct    [adverse]    conditions.”         30    C.F.R.
§§ 56.18002(a)(1), 57.18002(a)(1). MSHA cannot, without
explanation, justify the 2018 Amendment on the basis that it
will encourage mine operators to follow safety measures
already required by law in the very same regulation.
Moreover, MSHA has offered no basis for its conclusion that
                                 11
those supposed benefits will equal or exceed those yielded by
the 2017 Standard. Because the record lacks a reasonable
justification for the recordkeeping requirement’s supposed
safety benefits and any comparative analysis whatsoever,
MSHA’s explanation is arbitrary and capricious. See Amerijet
Int’l, Inc. v. Pistole, 753 F.3d 1343, 1350 (D.C. Cir. 2014)
(“conclusory statements will not do” under arbitrary and
capriciousness standard). 3




    3
       MSHA’s brief makes two additional arguments in support of
the recordkeeping requirement. It “reduces the risk of inundating
miners with information” and is “narrow” enough to lack safety
implications.     But these arguments do not appear in the
administrative record and thus we do not consider them. SEC v.
Chenery Corp., 318 U.S. 80, 87 (1943) (“The grounds upon which
an administrative order must be judged are those upon which the
record discloses that its action was based.”).

      Our dissenting colleague believes MSHA’s preamble statement
about “overwhelm[ing] the record with minor housekeeping issues”
counts as expressing concern about “inundating miners with
information.” Dissent at 7–8. We see no basis for concluding that
MSHA meant something other than what it said, especially
considering (1) the statement about “overwhelm[ing] the record”
appears in a paragraph regarding mine operator burdens,
Examinations of Working Places in Metal and Nonmetal Mines, 83
Fed. Reg. at 15,059, and (2) mine operators, not miners, maintain the
examination records, 30 C.F.R. § 56.18002(d) (“The operator shall
maintain the examination records for at least one year . . . .”).
Insofar as commenters raised a concern regarding the safety
implications of “cluttering the examination record,” Dissent at 8
(citing J.A. 769, 911), MSHA never adopted that concern as its own,
despite going out of its way to expressly adopt others. See
Examinations of Working Places in Metal and Nonmetal Mines, 83
Fed. Reg. at 15,059.
                              12
     The dissent would uphold MSHA’s conclusory
explanation and repeatedly takes us to task for not affording
MSHA enough deference. Dissent at 3–8. The dissent
locates its deference principle in National Mining Association
v. MSHA, 116 F.3d 520 (D.C. Cir. 1997) (per curiam), a case
in which we rejected no-less-protection standard challenges to
an MSHA safety standard, id. at 535–49. Importantly,
however, the petitioners there challenged MSHA’s factual
determinations that the new standard provided miners with as
much protection as the old standard. E.g., id. at 542 (“The
Union’s remaining challenges under the no-less protection rule
require only brief comment because they too involve
challenges to the Secretary’ net effects determinations that the
new regulation will not diminish the level of safety for miners
that existed under the prior regulations.” (emphases added)).
Applying “well-established principles of deference to agency
action,” id. at 536, we rejected the challenges because “we are
required to defer to the agency on factual determinations
underlying its decision,” including a net safety effects
determination, id. at 537. A deference standard for “factual
determinations” has little to do with the arbitrary and
capriciousness challenge before us.

     In addition, the dissent claims that, because MSHA’s thin
explanation for its compliance with the no-less-protection
standard in National Mining Association survived judicial
review, MSHA’s even thinner explanation here must do so as
well. Dissent at 4–5. Our colleague overlooks two crucial
points. First, the National Mining Association petitioners did
not challenge the adequacy of MSHA’s explanation for its
compliance with the no-less-protection standard and therefore
we did not decide whether that explanation would survive
arbitrary and capriciousness review. See Nat’l Mining Ass’n,
116 F.3d at 535–49. Any inferences the dissent divines from
National Mining Association regarding this issue are therefore
                                13
dicta. Second, National Mining Association upheld many
aspects of the challenged regulation, including those recited by
the dissent, see Dissent at 4–5, based on the petitioners’ failure
to provide evidence contradicting MSHA’s findings or
persuasive reasons for doubting its determinations. See, e.g.,
Nat’l Mining Ass’n, 116 F.3d at 539 (“The Union does not offer
any evidence to dispute the Secretary’s position.”); id. at 542
(“The Union has pointed to no reason to conclude that the
Secretary’s determination . . . is outweighed . . . .”); id. at 543
(finding “unpersuasive the Union’s contention that the new
regulation removes [] incentive[s] . . . .”). Here, by contrast,
MSHA had to contend with its own previous findings in
promulgating the 2017 Standard that requiring mine operators
to record all adverse conditions, including those that are
immediately corrected, helps “expedite[] the correction of
these conditions” and “identify[] trends” and “areas or subjects
that may benefit from increased safety emphasis.”
Examinations of Working Places in Metal and Nonmetal
Mines, 82 Fed. Reg. at 7686. Thus, an explanation that might
have sufficed in National Mining Association with MSHA
writing on a blank slate is inapplicable here with MSHA’s 2017
findings already on the books.

     In sum, MSHA failed to offer a reasoned explanation why
the examination and recordkeeping requirements of the 2018
Amendment satisfy the no-less-protection standard. The 2018
Amendment is therefore ultra vires and unenforceable. See 5
U.S.C. § 706(2)(A). The ordinary practice is to vacate
unlawful agency action. See id. § 706(2) (“The reviewing
court shall . . . set aside agency action . . . found to be”
unlawful). In rare cases, however, we do not vacate the action
but instead remand for the agency to correct its errors. MSHA
asks us to do so here. The appropriateness of the remand-
without-vacatur remedy turns on two factors: “(1) the
seriousness of the deficiencies of the action, that is, how likely
                              14
it is the agency will be able to justify its decision on remand;
and (2) the disruptive consequences of vacatur.” Heartland
Reg’l Med. Ctr. v. Sebelius, 566 F.3d 193, 197 (D.C. Cir. 2009)
(internal quotation marks, brackets, and ellipses omitted)
(quoting Fox Television Stations, Inc. v. FCC, 280 F.3d 1027,
1048–49 (D.C. Cir. 2002)). MSHA explains neither how the
2018 Amendment can be saved nor how vacatur will cause
disruption. We therefore take the normal course and vacate
the 2018 Amendment. 4

    The complicated procedural history of this case raises a
question about what standard governs after vacatur. See supra
at 4. We agree with the parties that vacatur of the 2018
Amendment automatically resurrects the 2017 Standard. The
2018 Amendment modifies the terms of the 2017 Standard and
so vacatur of the 2018 Amendment simply undoes those
modifications. Examinations of Working Places in Metal and
Nonmetal Mines, 83 Fed. Reg. at 15,056 (2018 Amendment
“makes changes to” Code of Federal Regulations provisions
“as amended by the Agency’s final rule on examinations of
working places that was published on January 23, 2017”). To
avoid any confusion, we order MSHA to reinstate the 2017
Standard upon issuance of the mandate attendant on this
opinion.

    For the foregoing reasons, we vacate the 2018 Amendment
and order the 2017 Standard reinstated.

                                                    So ordered.



    4
       Because we vacate the 2018 Amendment based on MSHA’s
failure to explain adequately its compliance with the no-less-
protection standard, we need not—and hence do not—consider the
petitioners’ remaining APA and Mine Act arguments.
     KATSAS, Circuit Judge, concurring in part and dissenting
in part:     The Mine Safety and Health Administration
promulgated a regulation requiring mine operators to
(1) “examine each working place at least once each shift before
miners begin work in that place” and (2) prepare a “record”
describing “each condition found that may adversely affect the
safety or health of miners.” Examinations of Working Places
in Metal and Nonmetal Mines, 82 Fed. Reg. 7680, 7695 (Jan.
23, 2017) (Mine Examinations I). After further review, MSHA
amended the regulation in two respects. Examinations of
Working Places in Metal and Nonmetal Mines, 83 Fed. Reg.
15,055, 15,057–58 (Apr. 9, 2018) (Mine Examinations II).
Operators now may conduct the examination “before work
begins or as miners begin work,” 30 C.F.R. § 56.18002(a)(1),
and the recording requirement now applies only to adverse
conditions that are “not corrected promptly,” id. § 56.18002(b).
I believe that MSHA adequately explained the second change
but not the first.

     The Federal Mine Safety and Health Act of 1977 contains
what has been described as a no-less-protection rule: “No
mandatory health or safety standard promulgated under this
subchapter shall reduce the protection afforded miners by an
existing mandatory health or safety standard.” 30 U.S.C.
§ 811(a)(9). When amending safety regulations, MSHA must
“state the basis for its conclusion that the rule has been
satisfied.” Nat’l Mining Ass’n v. MSHA, 116 F.3d 520, 536
(D.C. Cir. 1997) (per curiam).          Our review of this
determination is “highly deferential and presumes the validity
of agency action.” Id. (quotation marks omitted). So, we do
not lightly reject MSHA’s evaluation of the “net safety effects
of a change in a regulation,” id. at 542, or the “factual
determinations underlying its decision,” id. at 537.

    I agree with my colleagues that, even under this deferential
standard of review, MSHA failed to justify the amendment to
                               2
the examination requirement. MSHA asserted that miners
“will be notified” of adverse conditions “before they are
potentially exposed,” regardless of whether the examination is
conducted before or as they begin work. Mine Examinations
II, 83 Fed. Reg. at 15,058. But the regulation itself requires
only that operators “promptly notify” miners of adverse
“conditions found.” 30 C.F.R. § 56.18002(a)(1). It does not
guarantee that such conditions will be found before exposure—
which hardly seems inevitable if the examination is conducted
as miners begin work rather than before. Because MSHA did
not explain how miners would be notified of hazards before
exposure, its decision was arbitrary and capricious.

      In this Court, MSHA advanced more developed and more
plausible justifications for the amendment. Perhaps it would
be safe to conduct the examination as work begins, if the
inspector is always “just ahead” of the miners and warns them
of hazards “in real time.” Respondents’ Br. at 14. Perhaps this
would even improve safety, by minimizing “the risk that
conditions will be so changed” between the examination and
the beginning of work. Id. at 12. But MSHA did not assert
these justifications during the 2018 rulemaking. True, it noted
that mines have “dynamic work environments where
conditions are always changing.” Mine Examinations II, 83
Fed. Reg. at 15,057. But it did so only to urge a “best practice”
of conducting examinations “throughout the shift,” not to
suggest that examinations conducted as work begins are as safe
or safer than ones conducted before. See id. Of course, we
cannot uphold the amendment based on rationales that MSHA
first articulated in litigation, see Motor Vehicle Mfrs. Ass’n v.
State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 50 (1983), but the
agency remains free to consider them on remand.

     Unlike my colleagues, I would uphold the amendment
limiting the recording requirement to hazards that are not
                               3
promptly corrected. MSHA’s analysis of this amendment
balanced three competing safety considerations. First, MSHA
recognized that “recording all adverse conditions, even those
that are corrected promptly, would be useful in identifying
trends and areas that could benefit from an increased safety
emphasis.” Mine Examinations II, 83 Fed. Reg. at 15,059. But
MSHA then identified two countervailing considerations. It
reasoned that “a recording exception for adverse conditions
that are corrected promptly … encourages prompt correction of
adverse conditions.” Id. And it concluded that “requiring all
adverse conditions [to] be recorded in the examination record
would overwhelm the record with minor housekeeping issues.”
Id. The latter considerations are reasonable. Encouraging
prompt correction of hazards would seem to have obvious
safety benefits. Moreover, this Court has noted the risk of
“information overload,” Bldg. & Constr. Trades Dep’t, AFL-
CIO v. Brock, 838 F.2d 1258, 1277 (D.C. Cir. 1988) (quotation
marks omitted), and other federal agencies have acted to
prevent it, see, e.g., Truth in Lending, 74 Fed. Reg. 5244, 5281
(Jan. 29, 2009); Federal Motor Vehicle Safety Standards;
Occupant Crash Protection, 58 Fed. Reg. 46,551, 46,554
(Sept. 2, 1993).

     My colleagues object that the record lacks “any
comparative analysis.” Ante at 11. But MSHA did compare
the competing safety considerations. It concluded that the
amended recording rule would produce “as much or more in
safety benefits” by heightening incentives to correct hazards
promptly, and that decluttering examination records would
provide further safety benefits. Mine Examinations II, 83 Fed.
Reg. at 15,059. My colleagues respond that MSHA’s safety
assessment was too “conclusory.” Ante at 12. National Mining
indicates otherwise. There, we upheld various amendments to
mine-safety regulations challenged as inconsistent with the no-
                               4
less-protection rule. In four instances, MSHA’s explanation
was not materially different from the one at issue here.

     First, we upheld an amendment permitting the use of
electricity for vehicles to evacuate miners if a ventilation fan
shuts down. Commenters objected that electricity would be
dangerous in that circumstance, but MSHA asserted without
elaboration that the amendment would facilitate evacuations.
See Safety Standards for Underground Coal Mine Ventilation,
61 Fed. Reg. 9764, 9772 (Mar. 11, 1996) (Ventilation
Standards). We accepted the assertion and thought ourselves
“required to defer to the agency.” 116 F.3d at 537. We
explained: “In this case, the agency has determined that the
safety benefit gained by rapid evacuation of miners outweighs
the risk of ignition. We are poorly positioned to second-guess
the agency on the balancing of these two concerns.” Id.

     Second, we upheld an amendment limiting pre-shift
inspections to violations of rules presenting an immediate
hazard to miners. MSHA asserted that narrowing the
inspections would improve safety, because “look[ing] for
violations that might become a hazard could distract examiners
from their primary duties.” Ventilation Standards, 61 Fed.
Reg. at 9793. We accepted the explanation without plumbing
the record for more. 116 F.3d at 540.

    Third, we upheld an amendment permitting less frequent
inspection of fans that use an automated monitoring system.
MSHA asserted that the improved technology would “provide
greater safety” on balance. Safety Standards for Underground
Coal Mine Ventilation, 57 Fed. Reg. 20,868, 20,874 (May 15,
1992). Our response: “Where an evaluation is to be made of
the net safety effects of a change in a regulation, the court
properly defers to [MSHA’s] evaluation.” 116 F.3d at 542.
                               5
     Fourth, we upheld an amendment that narrowed another
inspection recording rule to exclude defects “corrected by the
end of th[e] shift.” 30 C.F.R. § 75.312(g)(1). Commenters
objected that the amendment would reduce safety by
eliminating information about “recurring problems that may
lead to bigger problems.” Ventilation Standards, 61 Fed. Reg.
at 9772. MSHA disagreed and asserted that “no safety purpose
is served by requiring examiners to record problems” that had
been promptly corrected. Id. We upheld the amendment, once
again based on “our deference to [MSHA’s] determination of
net effects.” 116 F.3d at 543.

     Given these holdings, we should accept MSHA’s
explanation in this case. The agency correctly understood the
governing legal question—whether the amendment reduced
health or safety protections for miners.           It identified
considerations reasonably bearing on that question. And it
compared the competing considerations to make an explicit
assessment of the “net safety effects of a change in a
regulation.” 116 F.3d at 542. As National Mining recognized,
we are “poorly positioned to second-guess the agency on the
balancing” of the relevant safety risks and benefits. Id. at 537.

     My colleagues object that the petitioners in National
Mining did not challenge “the adequacy of MSHA’s
explanation,” but only the “factual determinations that the new
standard provided miners with as much protection as the old
standard.” Ante at 12. Our opinion did not suggest that
distinction. Rather, it was framed as a review of MSHA’s
explanations: we held that MSHA must “state the basis for its
conclusion that the [no-less-protection] rule has been
satisfied;” then, we found “[i]n each case … no grounds to
conclude that the Secretary failed to engage in reasoned
decisionmaking.” 116 F.3d at 536. Moreover, there was no
reason to distinguish between MSHA’s explanation and its
                                6
factfinding. For each challenged regulation, the agency
identified safety benefits to the amended rule, acknowledged
countervailing costs, and concluded that the benefits
outweighed the costs. Those “factual determinations,” as my
colleagues describe them, were the agency’s explanation of
why each proposed amendment was consistent with the no-
less-protection rule. And as shown above, they were neither
different in kind from, nor more fully developed than, the
determination made here by MSHA.

     My colleagues further contend that MSHA failed to
address “its own previous findings” regarding the 2017
recording rule. Ante at 13. But MSHA did address its key prior
finding. In 2017, MSHA concluded that “recording all adverse
conditions, even those that are corrected immediately, will be
useful as a means of identifying trends.” Mine Examinations I,
82 Fed. Reg. at 7686. In assessing the 2018 amendment,
MSHA recognized that benefit of the 2017 rule, but concluded
that two competing safety considerations outweighed it. Mine
Examinations II, 83 Fed. Reg. at 15,059. In that respect, the
two analyses are consistent. In 2017, MSHA further stated: “a
record that notes the adverse conditions prior to miners
working in an area expedites the correction of these conditions
notwithstanding the regularity in which the adverse conditions
occur.” Mine Examinations I, 82 Fed. Reg. at 7686. That
statement addressed a suggestion to exclude from the recording
requirement uncorrected hazards that were “regularly
recurring.” See id. In 2018, no further comment on this point
was necessary, as there was no proposal to revisit the issue. In
2017, one commenter argued that excluding “immediately
corrected” hazards from the recording requirement “would
provide an incentive to immediately correct” them. Id. But
MSHA did not respond to this point, let alone compare the
safety benefits of that proposal to those of the rule adopted. See
id. Nor did MSHA need to make such a comparison—between
                               7
the 2017 rule and its eventual 2018 successor—in order to
conclude that the 2017 rule was safer than its 1979 predecessor.

     As for the two safety benefits noted by MSHA in 2018, my
colleagues question whether the 2018 rule will incentivize
mine operators to correct adverse conditions promptly, because
other regulations already require them to do so. Ante at 10. But
there is nothing unreasonable about providing increased
incentives for compliance, by reducing the recording
obligations of operators who do comply.

     Finally, my colleagues conclude that “the risk of
inundating miners with information” does not “appear in the
administrative record.” Ante at 11 n.3 (quotation marks
omitted). I read the record differently. As MSHA recounted,
some commenters warned that “requiring all adverse
conditions [to] be recorded in the examination record would
overwhelm the record with minor housekeeping issues.” Mine
Examinations II, 83 Fed. Reg. at 15,059. MSHA “agree[d]
with these commenters and conclude[d] that requiring mine
operators to record only those adverse conditions that are not
corrected promptly is as protective as the January 2017 rule.”
Id. Moreover, the commenters’ concern was a safety one.
They explained that a cluttered record risked “‘alarm fatigue,’
whereby too many warnings become background noise and no
one really hears them.” J.A. 911; see also J.A. 769. MSHA
reasonably credited that concern here—just as, in National
Mining, it reasonably credited the concern that an examination
record filled with corrected hazards might “distract [mine
operators] from the primary focus” of identifying ongoing
safety risks. 116 F.3d at 539.

    My colleagues note that MSHA adopted the relevant
comments “in a paragraph regarding mine operator burdens.”
Ante at 11 n.3. But the surrounding discussion does not change
                               8
the fact that MSHA agreed with commenters who expressed
concern that cluttering the examination record would harm
miner safety. Moreover, MSHA adopted these comments to
make a clear safety determination: “requiring mine operators
to record only those adverse conditions that are not corrected
promptly is as protective as the January 2017 rule.” Mine
Examinations II, 83 Fed. Reg. at 15,059. Under these
circumstances, “the agency’s path may reasonably be
discerned,” so we must “uphold the decision even if it is of less
than ideal clarity.” Press Commc’ns LLC v. FCC, 875 F.3d
1117, 1122 (D.C. Cir. 2017) (quotation marks omitted).

     In sum, I believe that MSHA adequately explained why
the 2018 amendment to the recording regulation is consistent
with the no-less-protection rule. Because my colleagues
conclude otherwise, I respectfully dissent from Part II.B of the
Court’s opinion.
