In re: National Nurses United, Et Al., Petitioners

United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued April 4, 2022 Decided August 26, 2022
No. 22-1002
IN RE: NATIONAL NURSES UNITED, ET AL.,
P ETITIONERS
On Petition For A Writ of Mandamus
Nicole J. Daro argued the cause for petitioners. With her
on the petition for a writ of mandamus and the reply were
Micah L. Berul, Carol A. Igoe, Jonathan Walters, David J.
Strom, Judy Rivlin, Harold Craig Becker, and Randy S.
Rabinowitz.
Joseph Gilliland, Attorney, U.S. Department of Labor,
argued the cause for respondents. On the opposition to the
petition for writ of mandamus were Edmund C. Baird,
Associate Solicitor for Occupational Safety and Health,
Heather R. Phillips, Counsel for Appellate Litigation, and
Anne E. Bonfiglio, Attorney. Johnda D. Bentley, Attorney,
entered an appearance.
Before: S RINIVASAN, Chief Judge, R AO , Circuit Judge,
and S ENTELLE, Senior Circuit Judge.
Opinion for the Court filed by Circuit Judge R AO .

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R AO , Circuit Judge: In June 2021, the Occupational Safety
and Health Administration (“OSHA”) promulgated an
emergency temporary standard to mitigate the risk of COVID-
19 transmission in healthcare settings (“Healthcare ETS”). In
December 2021, OSHA announced its intent to withdraw the
Healthcare ETS while continuing to work on the permanent
standard. National Nurses United and its co-petitioners (“the
Unions”) seek a writ of mandamus compelling OSHA (1) to
issue a permanent standard superseding the Healthcare ETS
within 30 days of the writ’s issuance; (2) to retain the
Healthcare ETS until a permanent standard supersedes it; and
(3) to enforce the Healthcare ETS.
We lack jurisdiction to compel OSHA to retain the
Healthcare ETS because doing so would not aid our current or
prospective jurisdiction as required for relief under the All
Writs Act. Moreover, mandamus is reserved only for
transparent violations of a clear duty to act. We cannot order
OSHA to promulgate a permanent standard because at the
conclusion of the rulemaking process, OSHA is permitted to
determine that no standard should issue. And enforcement of
the Healthcare ETS is squarely within OSHA’s prosecutorial
discretion and therefore inappropriate for judicial control
through mandamus. Therefore, we deny the petition in part and
dismiss it in part for lack of jurisdiction.
I.
A.
The Occupational Safety and Health Act (“Act”) was
enacted “to assure so far as possible every working man and
woman in the Nation safe and healthful working conditions and
to preserve our human resources.” Pub. L. No. 91-596, § 2(b),
84 Stat. 1590, 1590 (1970) (codified at 29 U.S.C. § 651(b)). To
that end, the Secretary of Labor may promulgate occupational

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safety and health standards that employers and employees must
comply with. 29 U.S.C. §§ 654(a)(2), (b), 655. The Secretary
exercises this authority through OSHA.
Section 6(b) of the Act establishes a set of notice and
comment procedures OSHA must follow to issue or amend
standards. See id. § 655(b). The Act allows the public to
comment on or object to a proposed standard and provides for
a public hearing on any objections. Id. § 655(b)(2)–(3). At the
end of the rulemaking proceeding, OSHA “shall issue a rule
promulgating, modifying, or revoking an occupational safety
or health standard or make a determination that a rule should
not be issued.” Id. § 655(b)(4).
Section 6(c) allows OSHA to bypass the Act’s procedural
requirements and promulgate a temporary standard in
emergency situations.1 29 U.S.C. § 655(c). If OSHA
“determines (A) that employees are exposed to grave danger
from exposure to substances … and (B) that [an] emergency
standard is necessary to protect employees from such danger,”
then OSHA “shall provide … for an emergency temporary
standard [“ETS”] to take immediate effect upon publication in
the Federal Register.” Id. § 655(c)(1). The ETS “shall be
effective until superseded by a standard promulgated in
accordance with the procedures prescribed” in section 6(c)(3).
Id. § 655(c)(2). Section 6(c)(3), in turn, says OSHA shall
commence the Act’s notice and comment procedures “[u]pon
publication of” the ETS, shall use the ETS as the proposed rule
for that proceeding, and “shall promulgate a standard … no
1 Emergency temporary standards have been extremely rare. From
the time the Act was enacted in 1970 until the COVID-19 pandemic,
OSHA had issued only nine of them. Nat’l Fed’n of Indep. Bus. v.
Dep’t of Lab., 142 S. Ct. 661, 663 (2022) (per curiam).

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later than six months after publication of the emergency
standard.” Id. § 655(c)(3).
Standards may be challenged by a person who is
“adversely affected” by petitioning a federal circuit court
within sixty days of when the standard is promulgated. Id.
§ 655(f). Once sixty days have elapsed, no court has
jurisdiction to review a pre-enforcement challenge to a
standard. Instead, the validity of a standard may be challenged
as a defense in an enforcement action. See id. § 660(a).
B.
Soon after taking office, President Biden directed OSHA
to “consider whether any emergency temporary standards on
COVID-19 … are necessary,” and if so, to issue them. Exec.
Order No. 13,999, § 2(b), 86 Fed. Reg. 7,211, 7,211 (Jan. 21,
2021). In response, OSHA determined that exposure to
COVID-19 “presents a grave danger” to healthcare workers,
and that an ETS is “necessary” to protect them. Based on these
findings, the Secretary promulgated the Healthcare ETS, which
set forth required precautionary measures in healthcare
occupational settings.2 Occupational Exposure to COVID-19;
Emergency Temporary Standard, 86 Fed. Reg. 32,376, 32,377
2 The Healthcare ETS requires, among other things, healthcare
employers to “develop and implement a COVID-19 plan,” as well as
policies to implement the Centers for Disease Control and
Prevention’s “Guidelines for Isolation Precautions,” 29 C.F.R.
§ 1910.502(c)(1), (e); to screen patients for COVID-19 symptoms
upon entry, id. § 1910.502(d); to provide for personal protective
equipment and physical distancing, id. § 1910.502(f), (h); to “limit
the number of employees present during” procedures that generate
aerosols, id. § 1910.502(g)(1); to implement cleaning and ventilation
protocols, id. § 1910.502(j)–(k); and to train employees on COVID-
19, id. § 1910.502(n).

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(June 21, 2021) (codified at 29 C.F.R. § 1910.502 et seq.)
(“Healthcare ETS”).
Shortly after issuing the Healthcare ETS, OSHA’s strategy
for combatting COVID-19 shifted. Rather than focusing
specifically on healthcare settings, OSHA developed and
promulgated an ETS requiring employees of all large
employers to either get vaccinated against COVID-19 or test
weekly. COVID-19 Vaccination and Testing; Emergency
Temporary Standard, 86 Fed. Reg. 61,402 (Nov. 5, 2021)
(“Vaccine ETS”). The Supreme Court held the Vaccine ETS
likely exceeded OSHA’s statutory authority. See Nat’l Fed’n
of Indep. Bus. v. Dep’t of Lab., 142 S. Ct. 661, 664–66 (2022)
(per curiam).
Because OSHA had allocated significant resources to
developing the Vaccine ETS, it had fallen behind on
promulgating a permanent COVID-19 standard for healthcare
settings. In December 2021, OSHA announced its intention to
withdraw the Healthcare ETS because it was unable to
complete the necessary notice and comment procedures within
the six-month timeframe.3 Statement on the Status of the OSHA
COVID-19 Healthcare ETS, OCCUPATIONAL S AFETY AND
HEALTH ADMIN. (Dec. 27, 2021), https://www.osha.gov/
coronavirus/ets. OSHA emphasized that COVID-19 still posed
a danger to healthcare workers and that the ETS was still
necessary to protect them. OSHA also explained it would
“continue to work expeditiously to issue a final standard” and,
until that time, “vigorously enforce … its general standards
… to help protect healthcare employees from the hazard of
3 The provisions of the Healthcare ETS relating to recordkeeping
were promulgated under different statutory authority and thus were
not subject to the six-month timeframe, so OSHA announced it was
not withdrawing them.

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COVID-19.” Id. Because it recognized it was unable to issue a
permanent standard “in a timeframe approaching the one
contemplated by the … Act,” OSHA announced that it would
withdraw the Healthcare ETS in a notice published in the
Federal Register. Id.
Before OSHA withdrew the ETS, the Unions filed this
petition for mandamus. OSHA decided not to publish the
withdrawal while the petition was pending, so the Healthcare
ETS remains on the books. But OSHA conceded at oral
argument that it was no longer enforcing the ETS.
II.
The Unions petition for a writ of mandamus compelling
OSHA (1) to issue a permanent standard superseding the
Healthcare ETS within 30 days; (2) to refrain from
withdrawing the Healthcare ETS until it promulgates a
permanent standard; and (3) to continue enforcing the
Healthcare ETS. They seek relief pursuant to the All Writs Act,
which empowers this court to “issue all writs necessary or
appropriate in aid of [its] … jurisdiction[] and agreeable to the
usages and principles of law.” 28 U.S.C. § 1651(a). When a
party requests a writ of mandamus against an agency under the
All Writs Act, we undertake a three-step inquiry.
First, we must ensure that we have jurisdiction by
considering whether issuing the writ would protect our current
or prospective jurisdiction.4 The All Writs Act does not grant
4 This jurisdictional inquiry should not be confused with the inquiry
for a writ of mandamus sought under the Mandamus Act. Pub L. No.
87-748, 76 Stat. 744 (1962) (codified at 28 U.S.C. § 1361). That Act
grants district courts “original jurisdiction of any action in the nature
of mandamus,” 28 U.S.C. § 1361, which they have “only if: (1) the

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jurisdiction to issue a writ of mandamus. In re Tennant, 359
F.3d 523, 527 (D.C. Cir. 2004). Instead, it authorizes the
issuance of a writ of mandamus in aid of jurisdiction this court
already has or will have as a result of issuing the writ. See id.
at 527–28. When an agency unlawfully withholds or
unreasonably delays an action this court would have
jurisdiction to review, the All Writs Act empowers us to issue
a writ compelling the agency to complete the action so we can
exercise our jurisdiction to review it. Telecomms. Rsch. &
Action Ctr. v. FCC (“TRAC”), 750 F.2d 70, 75–76 (D.C. Cir.
1984). If, on the other hand, the court does not and would not
have jurisdiction to review the agency action sought by
petitioners, it cannot bootstrap jurisdiction via the All Writs
Act. See id. at 77 (explaining that when a court “has no present
or future jurisdiction over agency actions … it can contemplate
no exercise of jurisdiction that mandamus might aid”); In re
Stone, 569 F.2d 156, 157 (D.C. Cir. 1978) (per curiam) (“We
have no appellate jurisdiction over the instant case, past,
present, or future, which mandamus could ‘aid.’ Therefore we
lack jurisdiction to issue the writ.”).
Second, if the court has jurisdiction, it must consider
whether the agency has a crystal-clear legal duty to act. The
writ remains “reserved only for the most transparent violations
of a clear duty to act.” In re Core Commc’ns, Inc., 531 F.3d
849, 855 (D.C. Cir. 2008) (cleaned up). The duty must be
incontrovertible and not a matter within the agency’s
discretion. See Thomas v. Holder, 750 F.3d 899, 904 (D.C. Cir.
plaintiff has a clear right to relief; (2) the defendant has a clear duty
to act; and (3) there is no other adequate remedy available to
plaintiff,” Muthana v. Pompeo, 985 F.3d 893, 910 (D.C. Cir. 2021)
(cleaned up), cert. denied, 142 S. Ct. 757 (2022). In All Writs Act
cases, these three requirements inform whether mandamus is
appropriate on the merits, but not whether we have jurisdiction.

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2014) (explaining that “if the act [petitioners] seek to compel
is discretionary,” then the writ cannot issue, “as government
officials have no clear duty to perform such acts”). Under the
All Writs Act, we may issue only those writs “necessary or
appropriate” and “agreeable to the usages and principles of
law.” 28 U.S.C. § 1651(a). When courts assess whether an
agency has a clear duty to act, we look to the statutory
requirements imposed by Congress and whether an Executive
Branch agency retains discretion over a particular action.
Third, even when a clear duty exists, we consider whether
judicial intervention would be appropriate because the writ of
mandamus is a drastic remedy reserved for extraordinary
circumstances. See Cheney v. U.S. Dist. Ct., 542 U.S. 367, 380
(2004); In re Pub. Emps. for Env’t Resp., 957 F.3d 267, 273
(D.C. Cir. 2020). In cases of alleged agency delay, we will not
issue the writ unless the agency’s delay in fulfilling its duty “is
so egregious as to warrant mandamus.” TRAC, 750 F.2d at 79.
A.
We turn first to the Unions’ request for the writ of
mandamus to compel OSHA to issue a permanent standard
within thirty days. Recognizing that in some situations
OSHA’s duty to complete its rulemaking procedures is clear,
we have in the past ordered OSHA to expedite its rulemaking
process. See, e.g., Pub. Citizen Health Rsch. Grp. v. Auchter,
702 F.2d 1150, 1157–58 (D.C. Cir. 1983) (per curiam). But the
Unions are not asking this court to compel OSHA to complete
the rulemaking process triggered by the Healthcare ETS.
Rather, they petition this court to compel OSHA to reach a
particular result from that process—the promulgation of a
permanent standard. Their petition makes this clear throughout,
particularly in the request for relief, which asks for a writ of
mandamus ordering OSHA to “[i]ssue … a Permanent

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Standard for Healthcare Occupational Exposure to COVID-
19.” In that regard, while the Unions acknowledge OSHA has
“discretion as to the content of any standard,” they maintain
OSHA has a “a statutory duty to impose some type of
mandatory, legally-enforceable obligations on employers
sufficient to protect healthcare employees from” COVID-19.
Because OSHA has not withdrawn the findings that a standard
is necessary to combat a grave danger, the Unions argue that
the Act mandates the eventual adoption of a permanent
standard addressing these dangers. The Unions further contend
the Act requires OSHA to promulgate the permanent standard
within six months and that its failure to do so constitutes a delay
egregious enough to warrant mandamus.
At the outset, we have jurisdiction to grant this relief.
When a statute grants courts of appeals jurisdiction to review
agency action, the All Writs Act empowers those courts to
issue a writ of mandamus compelling the agency to complete
the action. TRAC, 750 F.2d at 75–76. The Occupational Safety
and Health Act commits review of OSHA standards to the
courts of appeals. 29 U.S.C. § 655(f). Although this court does
not have jurisdiction over proposed, i.e., not final, standards,
the court may compel the agency to finalize a standard so that
it may review it. See Int’l Union, United Auto., Aerospace &
Agric. Implement Workers of Am., UAW v. Donovan (“UAW”),
756 F.2d 162, 163 (D.C. Cir. 1985) (recognizing the court of
appeals had jurisdiction to order OSHA to issue a standard).
We therefore have jurisdiction to consider whether mandamus
should issue to compel OSHA to promulgate a permanent
standard.
Turning to the merits, we find that OSHA does not have a
clear duty to issue a permanent standard. Writs of mandamus
are “reserved only for the most transparent violations of a clear
duty to act.” In re Bluewater Network, 234 F.3d 1305, 1315

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(D.C. Cir. 2000). While OSHA has a clear duty to follow an
ETS with a rulemaking proceeding, OSHA does not have a
clear duty to promulgate a permanent standard at the end of that
proceeding.
The Act states that “[u]pon publication of” an ETS, “the
Secretary shall commence a proceeding in accordance with
subsection (b)” and “shall promulgate a standard under this
paragraph no later than six months after publication of the
emergency standard.” 29 U.S.C. § 655(c)(3). “[T]he word
‘shall’ usually connotes a requirement.” Kingdomware Techs.,
Inc. v. United States, 579 U.S. 162, 171 (2016). Courts look to
context to confirm whether “shall” imposes a mandatory
obligation or whether instead “the context of a particular usage
… require[s] the construction of … ‘shall’ as permissive.” LO
Shippers Action Comm. v. ICC, 857 F.2d 802, 806 (D.C. Cir.
1988); see also Me. Cmty. Health Options v. United States, 140
S. Ct. 1308, 1321 (2020) (explaining that a section’s “adjacent
provisions … underscore[d] its mandatory nature”). When
context confirms that “shall” is used in its ordinary, mandatory
sense, it imposes a clear duty to act.
Read in context, the Act creates a mandatory duty to
follow an ETS with a rulemaking proceeding. The Act provides
that after the issuance of an ETS, “the Secretary shall
commence a proceeding in accordance with subsection (b),”
which outlines the notice and comment procedures to
promulgate permanent standards. 29 U.S.C. § 655(c)(3); see
also id. § 655(b). OSHA may adopt an emergency temporary
standard without following the ordinary procedural safeguards.
Congress, however, circumscribed that emergency exception
by requiring OSHA to use the ETS as a proposed rule,
undertake notice and comment, and determine whether to
promulgate a permanent standard. See id. § 655(c)(3). In this
context, “shall” imposes a mandatory requirement on the

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agency to follow the ETS with a permanent rulemaking
process. If that process were optional, OSHA could simply
impose standards through the emergency exception and avoid
the Act’s rulemaking procedures. But these procedures ensure
that permanent standards imposing obligations on private
parties are promulgated only after public participation and
agency deliberation. We decline to read the Act in a manner
that creates a loophole for the agency to avoid the rulemaking
requirements prescribed by Congress.
While the rulemaking process is mandatory, promulgating
a permanent standard is not. The Act states that the agency
“shall promulgate a standard … no later than six months after
publication of the emergency standard” but also that any
standard following an ETS be promulgated “in accordance with
subsection (b).” 29 U.S.C. § 655(c)(3). Contrary to the Unions’
assertions, the Act imposes no requirement to promulgate a
permanent standard. Any permanent standard must be
promulgated in accordance with the ordinary rulemaking
process in the Act, which plainly provides that OSHA may
conclude the process either by promulgating a permanent
standard or by “mak[ing] a determination that a [standard]
should not be issued.” Id. § 655(b)(4). OSHA is permitted to
choose either path, which means it does not have a clear duty
to promulgate a permanent standard. Reading the provisions
together and in context, OSHA has no clear duty to issue a
permanent standard because it has a clear duty to undertake a
notice and comment process, and that process may result in a
determination that no permanent standard is necessary.
The Unions maintain that OSHA must issue a permanent
standard because the agency has not withdrawn its findings that
COVID-19 poses a grave danger and that a healthcare standard
is necessary. The fact of these findings, which supported the
Healthcare ETS, does not necessitate the issuance of a

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permanent standard. If it did, there would be little to be gained
by undertaking the rulemaking process mandated by the Act.
The purpose of that process is to allow public input as the
agency considers a health and safety problem and fashions the
appropriate regulatory solutions. The Unions concede that after
reviewing public comments, OSHA will have “discretion as to
the content of any standard regulating workplace exposures to
COVID-19.” As the Act explicitly recognizes, part of OSHA’s
discretion with respect to the content of these standards
includes the discretion to decide that no permanent standard
should issue at all. See 29 U.S.C. § 655(b)(4). At the end of the
rulemaking process, OSHA may determine that COVID-19 is
not a grave danger within the meaning of the Act or that no
standard is necessary. Or OSHA may maintain the findings in
the Healthcare ETS and decide to promulgate a standard. We
cannot issue a writ of mandamus ordering OSHA to follow one
path or another.
In sum, while OSHA has a clear duty to follow the notice
and comment process to determine what standard, if any,
should supersede the Healthcare ETS, it has discretion to
determine that no standard should issue. The Unions petition
for more than just the expeditious completion of OSHA’s
process, they ask this court to compel OSHA to promulgate a
permanent standard. OSHA has no clear duty to issue a
permanent standard, so we cannot compel the agency to do so.
B.
The Unions also petition for the writ of mandamus to
compel OSHA to retain the Healthcare ETS until it
promulgates a permanent standard.5 Although the government
5 The Unions were correct to request a writ of mandamus, as opposed
to a stay, even though their request to “retain” the Healthcare ETS is

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does not contest our jurisdiction to decide whether the Unions
are entitled to this relief, we “have an independent obligation
to determine whether subject-matter jurisdiction exists.”
Arbaugh v. Y & H Corp., 546 U.S. 500, 514 (2006). Because
retaining the Healthcare ETS does not serve our current or
prospective jurisdiction, we cannot grant this relief.
As explained above, the All Writs Act “does not expand
the jurisdiction of a court.” TRAC, 750 F.2d at 76. Instead, it
allows a court to issue writs, including a writ of mandamus, to
protect jurisdiction it already has or will have once an “appeal
has been perfected.” Id. (cleaned up). We only have jurisdiction
to compel an agency to take an action we would ultimately have
jurisdiction to review.
Ordering OSHA to “retain” the Healthcare ETS, i.e., to
refrain from withdrawing it, does not protect our current or
prospective jurisdiction because we do not now, nor would we
in the future, have jurisdiction to review pre-enforcement
challenges to the Healthcare ETS. The Act grants courts of
appeals jurisdiction to review “a petition challenging the
validity” of a standard brought by “[a]ny person who may be
adversely affected by [the] standard.” 29 U.S.C. § 655(f). But
petitions must be brought “prior to the sixtieth day after such
standard is promulgated.” Id. After sixty days, no court has
jurisdiction under the Act to review a standard unless and until
a request “to preserve the status quo.” Cf. In re NTE Conn., LLC, 26
F.4th 980, 988 n.2 (D.C. Cir. 2022). Because the mechanism by
which the Unions seek to maintain the status quo is an order telling
OSHA “what … not to do,” the petition properly asks for a writ of
mandamus. See Nken v. Holder, 556 U.S. 418, 428 (2009)
(explaining that an injunction, which is similar to a writ of
mandamus, “is a means by which a court tells someone what to do
or not to do,” whereas “a stay operates upon the judicial proceeding
itself … by temporarily divesting an order of enforceability”).

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OSHA enforces it. See Simplex Time Recorder Co. v. Sec’y of
Lab., 766 F.2d 575, 582 n.2 (D.C. Cir. 1985) (“[N]o pre-
enforcement challenges to a standard can be entertained in the
courts of appeals unless the requirements of section 6(f) are
met.”) (emphasis omitted); see also Kiewit Power Constructors
Co. v. Sec’y of Lab., 959 F.3d 381, 390 (D.C. Cir. 2020)
(“Although section 6(f) would be the exclusive method for
obtaining pre-enforcement judicial review of a standard, the
provision does not foreclose an employer from challenging the
validity of a standard during an enforcement proceeding.”)
(cleaned up).
Because the sixty-day time limit expired long before the
Unions’ petition, we do not have current or prospective
jurisdiction over pre-enforcement challenges to the Healthcare
ETS. Compelling OSHA to retain the Healthcare ETS would
therefore not protect our jurisdiction to review it.
The Unions make two arguments in favor of our
jurisdiction. First, they suggest that because the Act says “[t]he
Secretary shall provide … for an emergency temporary
standard … if he determines” that one is necessary to protect
workers from a grave danger, 29 U.S.C. § 655(c)(1), the Act
creates a “substantive statutory mandate” to have an ETS when
those conditions are met, which we can compel OSHA to
“carry out,” Pub. Citizen Health Rsch. Grp. v. Comm’r, FDA,
740 F.2d 21, 32 (D.C. Cir. 1984).
Even assuming the Secretary has a non-discretionary duty
to issue an ETS in certain situations, the Unions’ argument
conflates ordering OSHA to issue an ETS with ordering OSHA
to retain an ETS it has already issued. Because we have
jurisdiction to review an ETS if a challenge is brought within
sixty days of its promulgation, we have jurisdiction under the
All Writs Act to compel OSHA to issue an ETS. See UAW, 756

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F.2d at 163. Once an ETS has issued, however, the judicial
review clock begins to run, defeating our jurisdiction as
explained above.
Second, the Unions contend we have jurisdiction to
compel OSHA to retain the ETS because it serves as the
proposed rule for a permanent standard. In International
Union, United Mine Workers of America v. U.S. Department of
Labor, we explained that although we did not have jurisdiction
to review the withdrawal of a proposed standard under the
Mine Act, the All Writs Act empowered us to compel the
agency to promulgate the withdrawn standard since we would
have jurisdiction to review it after promulgation. 358 F.3d 40,
42–43 (D.C. Cir. 2004). Because the Healthcare ETS serves as
the proposed rule for a permanent standard, the Unions
maintain we would have jurisdiction to review the permanent
standard if a petition was filed within sixty days.
But our jurisdiction over the permanent standard is
unaffected by whether OSHA retains the Healthcare ETS. As
explained above, OSHA’s duty to commence and eventually
complete section 6(b)’s notice and comment process is
mandatory. The Healthcare ETS will serve as the proposed rule
for the proceeding whether it is withdrawn or retained. See 29
U.S.C. § 655(c)(3) (“Upon publication of [an ETS] … the
Secretary shall commence a proceeding in accordance with
subsection (b) … and the standard as published shall also serve
as a proposed rule for the proceeding.”). If OSHA decides to
promulgate a permanent standard at the conclusion of the
rulemaking process, we will have jurisdiction to review it. But
because the ETS serves as the proposed rule regardless of
whether it is retained, compelling OSHA to retain the ETS
would not aid our prospective jurisdiction.

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C.
Finally, we turn to the Unions’ petition to compel OSHA
to enforce the Healthcare ETS. We have jurisdiction to issue
this writ because if OSHA enforced the Healthcare ETS, we
would have jurisdiction to review challenges to it as a defense
to an enforcement action. 29 U.S.C. § 660(a); Kiewit Power
Constructors Co., 959 F.3d at 390–91.
We cannot grant this relief, however, because OSHA’s
decision not to enforce the Healthcare ETS does not violate a
clear duty to act. OSHA’s determination of whether, when, and
how vigorously to enforce a particular standard is committed
to the agency’s discretion and not subject to judicial review.
See Arpaio v. Obama, 797 F.3d 11, 16 (D.C. Cir. 2015) (“[A]ll
agencies have discretion to prioritize in light of the Secretary’s
and, ultimately, the President’s assessments ‘whether agency
resources are best spent on this violation or another, whether
the agency is likely to succeed if it acts, whether the particular
enforcement action requested best fits the agency’s overall
policies, and, indeed, whether the agency has enough resources
to undertake the action at all.’”) (quoting Heckler v. Chaney,
470 U.S. 821, 831 (1985)); see also Nat’l Roofing Contractors
Ass’n v. U.S. Dep’t of Lab., 639 F.3d 339, 343 (7th Cir. 2011)
(recognizing agency enforcement discretion in the OSHA
context).
Writs of mandamus are reserved for “the ordering of a
precise, definite act about which an official ha[s] no discretion
whatever.” Norton v. S. Utah Wilderness All., 542 U.S. 55, 63
(2004) (cleaned up). We cannot compel OSHA to enforce the
Healthcare ETS because its discretion over which standards to
enforce and when is the antithesis of a clear duty to act.

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* * *
For the foregoing reasons, we deny in part and dismiss in
part the Unions’ petition for a writ of mandamus.
So ordered.

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