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United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued October 7, 2002 Decided July 8, 2003
No. 01-1335
SECRETARY OF LABOR,
MINE SAFETY AND HEALTH ADMINISTRATION,
PETITIONER
v.
EXCEL MINING, LLC, AND
FEDERAL MINE SAFETY AND HEALTH REVIEW COMMISSION,
RESPONDENTS
On Petition for Review of an Order of the
Federal Mine Safety and Health Review Commission
Robin A. Rosenbluth, Attorney, U.S. Department of Labor,
argued the cause for petitioner. With her on the briefs was
W. Christian Schumann, Counsel.
Grant Crandall and Judith Ellen Rivlin were on the brief
for amicus curiae United Mine Workers of America in sup-
port of petitioner.
Bills of costs must be filed within 14 days after entry of judgment.
The court looks with disfavor upon motions to file bills of costs out
of time.
2
Timothy M. Biddle argued the cause for respondent Excel
Mining, LLC. With him on the brief were Thomas C. Means
and Edward M. Green.
Before: SENTELLE, ROGERS, and GARLAND, Circuit Judges.
Opinion for the Court filed by Circuit Judge GARLAND.
Opinion dissenting filed by Circuit Judge SENTELLE.
GARLAND, Circuit Judge: For some 25 years, the Secretary
of Labor has determined whether coal mine operators are
complying with standards limiting miners’ exposure to respir-
able coal dust by using a methodology that averages multiple
dust samples taken over a single shift. In 1999, the Secre-
tary issued three citations to Excel Mining, LLC for violating
those standards. Excel appealed to the Federal Mine Safety
and Health Review Commission, contending that the Secre-
tary’s longstanding compliance methodology was unlawful
under the Federal Mine Safety and Health Act of 1977 (the
‘‘Mine Act’’), 30 U.S.C. § 801 et seq., and that the only lawful
method was to average multiple samples taken over multiple
shifts. The Commission agreed with Excel and vacated the
citations. The Secretary now petitions for review of the
adverse judgment of the Commission. We grant the petition
and reverse.
I
Congress enacted the Federal Coal Mine Health and Safety
Act of 1969 (the ‘‘Coal Act’’) ‘‘to develop and promulgate
improved mandatory health or safety standards to protect the
health and safety of the Nation’s coal miners.’’ Pub. L. No.
91–173, § 2(g), 83 Stat. 742, 743 (1969). In 1977, Congress
incorporated the Coal Act into the more comprehensive Mine
Act, Pub. L. No. 95–164, 91 Stat. 1290 (1977) (codified as
amended at 30 U.S.C. § 801 et seq.). See Secretary of Labor
v. Cannelton Indus., Inc., 867 F.2d 1432, 1433 (D.C. Cir.
1989). The new legislation brought the mining of coal, met-
als, and non-metals under the same regulatory scheme and
transferred enforcement powers and other duties from the
3
Secretary of the Interior to the Secretary of Labor. See 30
U.S.C. § 961(a).
Sections 101 and 103 of the Mine Act authorize the Secre-
tary to promulgate mandatory safety and health standards
for the nation’s mines and to conduct regular inspections of
those mines. See 30 U.S.C §§ 811, 813. Section 202(b)(2) of
the Mine Act, originally enacted as part of the Coal Act, set
the initial exposure standard for respirable coal dust at 2.0
milligrams per cubic meter of air. 30 U.S.C. § 842(b)(2).
The section was intended ‘‘to provide, to the greatest extent
possible, that the working conditions in each underground
coal mine are sufficiently free of respirable dust concentra-
tions in the mine atmosphere to permit each miner the
opportunity to work underground during the period of his
entire adult working life without incurring any disability from
pneumoconiosis [‘‘black lung’’ disease] or any other occupa-
tion-related disease during or at the end of such period.’’ 30
U.S.C. § 841(b).
Section 202(b)(2) provides as follows:
[E]ach operator shall continuously maintain the average
concentration of respirable dust in the mine atmosphere
during each shift to which each miner in the active
workings of such mine is exposed at or below 2.0 milli-
grams of respirable dust per cubic meter of air.
30 U.S.C. § 842(b)(2) (emphasis added). The current manda-
tory health standard for respirable coal dust in underground
mines, adopted by the Secretary of Labor in 1980 and codified
at 30 C.F.R. § 70.100(a), tracks this statutory language. See
Respirable Dust, 45 Fed. Reg. 23,990, 23,994–95, 24,001 (Apr.
8, 1980). The statutory term ‘‘average concentration’’ — of
key import in this case — is defined in § 202(f) of the Mine
Act as follows:
[T]he term ‘‘average concentration’’ means a determina-
tion which accurately represents the atmospheric condi-
tions with regard to respirable dust to which each miner
in the active workings of a mine is exposed (1) as
measured, during the 18 month period following Decem-
4
ber 30, 1969, over a number of continuous production
shifts to be determined by the Secretary [of Labor;
originally, the Secretary of the Interior] and the Secre-
tary of Health and Human Services [originally, the Sec-
retary of Health, Education, and Welfare (HEW)], and
(2) as measured thereafter, over a single shift only,
unless the Secretary [of Labor] and the Secretary of
Health and Human Services find, in accordance with the
provisions of section 811 of this title, that such single
shift measurement will not, after applying valid statistical
techniques to such measurement, accurately represent
such atmospheric conditions during such shift.
30 U.S.C. § 842(f).
Section 202(f) of the Mine Act is taken essentially verbatim
from § 202(f) of the Coal Act. In 1972, acting pursuant to
the Coal Act, the Secretaries of the Interior and HEW made
the joint finding referred to in § 202(f), concluding that
‘‘single shift measurement of respirable dust will not, after
applying valid statistical techniques to such measurement,
accurately represent the atmospheric conditions to which the
miner is continuously exposed.’’ Notice of Finding That a
Single Shift Measurement of Respirable Dust Will Not Accu-
rately Represent Atmospheric Conditions During Such Shift,
37 Fed. Reg. 3833 (Feb. 23, 1972) [hereinafter Joint Finding].
Pursuant to Mine Act § 301(b)(1) and (c)(2), all standards,
decisions, determinations, and regulations issued under the
Coal Act remain in effect under the Mine Act until modified
or set aside. 30 U.S.C. § 961(b)(1), (c)(2). The Joint Finding
has not been modified or set aside, and continues in effect.1
To ensure compliance with mandatory health standards,
Mine Act § 103(a) directs the Labor Department’s Mine
Safety and Health Administration (MSHA) to test the atmo-
sphere of each underground mine ‘‘in its entirety’’ at least
four times annually. 30 U.S.C. § 813(a). If ‘‘upon inspection
1The Secretary of Labor and the Secretary of Health and Human
Services have recently proposed rescinding the 1972 Joint Finding.
See Determination of Concentration of Respirable Coal Mine Dust,
68 Fed. Reg. 10,940 (Mar. 6, 2003).
5
or investigation’’ a MSHA inspector discovers a violation of
the Mine Act or of a mandatory standard, he must issue a
citation to the operator. Id. § 814(a). Section 110(a) of the
Mine Act provides for the assessment of civil penalties for
such violations. Id. § 820(a). An operator can appeal to the
Federal Mine Safety and Health Review Commission
(FMSHRC or the ‘‘Commission’’), id. § 815(d), and the losing
party can then seek review before the appropriate United
States Court of Appeals, id. § 816.
Since 1975, the Secretary of the Interior and his successor,
the Secretary of Labor, have based regular compliance deter-
minations under the respirable dust standard on the average
of multiple measurements taken over a single shift. See Coal
Mine Respirable Dust Standard Noncompliance Determina-
tions, 63 Fed. Reg. 5687, 5687 (Feb. 3, 1998); Joint Stipula-
tions and Statements of Uncontested Fact at 3 (J.A. at 8)
[hereinafter Joint Stip.]. Using this methodology, MSHA
inspectors collect respirable dust samples during one full shift
from miners assigned to different occupations in the same
mechanized mining unit. 63 Fed. Reg. at 5687; Joint Stip. at
3 (J.A. at 8). The samples are then averaged, and MSHA
issues a citation under 30 C.F.R. § 70.100(a) if the average
concentration of respirable dust from all of the occupations
exceeds the applicable standard. 63 Fed. Reg. at 5687; Joint
Stip. at 3 (J.A. at 8).
In March 1999, MSHA inspectors issued three citations to
Excel Mining, charging violations of § 70.100(a)’s respirable
dust standard. Each citation was based on an average of
multiple samples taken over a single shift, and in each case
the average respirable dust concentration substantially ex-
ceeded the applicable standard. See Joint Stip. at 2 (J.A. at
7). Excel contested the citations before the Commission,
maintaining that under both Mine Act § 202(f) and the 1972
Joint Finding, MSHA was barred from using any kind of
single-shift sampling for enforcement purposes and was limit-
ed to multiple-shift sampling exclusively. The Secretary took
the position that, although the statute and Joint Finding
barred her from making a compliance determination on the
basis of a single full-shift sample, she was free to make such a
6
determination based on an average of multiple samples taken
over a single shift (‘‘multiple single-shift samples’’).2
The Commission ruled in favor of Excel and vacated the
three citations. Excel Mining, LLC v. Sec’y of Labor, 23
FMSHRC 600 (2001). Two commissioners concluded that
both § 202(f) and the Joint Finding ‘‘envision[ed] but two
methods of respirable dust sampling — single-shift measure-
ments and measurements derived from samples taken over a
number of continuous production shifts,’’ and that together
they unambiguously barred ‘‘all single shift sampling.’’ Id. at
605, 606 (Riley and Verheggen, Comm’rs). A third commis-
sioner agreed with the Secretary that the Joint Finding was
ambiguous on the question, but concluded that the Secre-
tary’s interpretation was unreasonable on policy grounds. Id.
at 614 (Beatty, Comm’r, concurring).3 Exercising her statu-
2 The Secretary describes single full-shift sampling as follows:
A single, full-shift measurement of respirable coal mine dust is
obtained with an approved sampler unit, which is either worn
or carried by the miner TTT during the entire shiftTTTT A
portable, battery-powered pump draws dust-laden mine air TTT
through the pre-weighed filter leaving the particles deposited
on the filter surfaceTTTT The concentration of respirable dust,
expressed as milligrams per cubic meter (mg/m3) of air, is
determined by dividing the observed weight gain [of the filter]
by the volume of mine air passing through the filter and then
multiplying this quantity by a conversion factorTTTT
Determination of Concentration of Respirable Coal Mine Dust, 65
Fed. Reg. 42,068, 42,091 (July 7, 2000). All three of the methodolo-
gies discussed here — single full-shift sampling, multiple single-
shift sampling, and multiple-shift sampling — involve collecting dust
over entire shifts, and hence are properly described as full-shift
sampling. See Excel Br. at 5 n.4.
3 The fourth commissioner dissented, concluding that the 1972
Joint Finding was invalid, and that § 202(f) should therefore be
interpreted as if no finding had been made. 23 FMSHRC at 615–20
(Jordan, Chairman, dissenting). Since neither of the parties makes
that argument here, we do not consider it. See Narragansett
Indian Tribe v. Nat’l Indian Gaming Comm’n, 158 F.3d 1335, 1338
(D.C. Cir. 1998).
7
tory right under 30 U.S.C. § 816, the Secretary petitions for
review of the Commission’s decision.
II
The standard of review applicable to this petition is set out
in our opinion in Cannelton Industries, 867 F.2d at 1435.
Under the Mine Act, the Secretary’s interpretation of the law
must ‘‘ ‘be given weight by both the Commission and the
courts.’ ’’ Id. (quoting S. REP. NO. 95–181, at 49 (1977)).
When, as here, ‘‘the Secretary and the Commission divide, it
[is] TTT the Secretary rather than the Commission [who] is
entitled to the deference described in Chevron U.S.A. Inc. v.
Natural Resources Defense Council, Inc., 467 U.S. 837
(1984).’’ Id.; see RAG Cumberland Res. LP v. FMSHRC,
272 F.3d 590, 596 (D.C. Cir. 2001); Secretary of Labor v.
FMSHRC, 111 F.3d 913, 920 (D.C. Cir. 1997); cf. Martin v.
Occupational Safety & Health Review Comm’n, 499 U.S. 144,
152–53 (1991).
Under the first step of Chevron, ‘‘this court TTT ‘must give
effect to the unambiguously expressed intent of Congress.’ ’’
Cannelton Indus., 867 F.2d at 1435 (quoting Chevron, 467
U.S. at 843). But ‘‘when ‘the statute is silent or ambiguous
with respect to the specific issue,’ the question for this court
TTT is whether the Secretary’s interpretation is ‘a permissible
construction of the statute.’ ’’ Id. (quoting Chevron, 467 U.S.
at 843); see Secretary of Labor v. FMSHRC, 111 F.3d at 916.
Under this second step, the court must defer to ‘‘a reasonable
interpretation made by the administrator of [the] agency.’’
Chevron, 467 U.S. at 844. Moreover, in the statutory scheme
of the Mine Act, ‘‘ ‘the Secretary’s litigating position before
[the Commission] is as much an exercise of delegated law-
making powers as is the Secretary’s promulgation of a TTT
health and safety standard,’ ’’ and is therefore deserving of
deference. RAG Cumberland, 272 F.3d at 596 n.9 (quoting
Martin, 499 U.S. at 157).4
4 Compare Martin, 499 U.S. at 157 (holding that, ‘‘when embodied
in [an OSH Act] citation, the Secretary’s interpretation assumes a
form expressly provided for by Congress’’ (citations omitted)), with
8
The ‘‘Secretary is emphatically due this [same] respect
when she interprets her own regulations.’’ Cannelton Indus.,
867 F.2d at 1435 (citing Ford Motor Credit Co. v. Milhollin,
444 U.S. 555, 566 (1980)). We must defer to her interpreta-
tion ‘‘ ‘unless it is plainly erroneous or inconsistent with the
regulation.’ ’’ Akzo Nobel Salt, Inc. v. FMSHRC, 212 F.3d
1301, 1303 (D.C. Cir. 2000) (quoting Thomas Jefferson Univ.
v. Shalala, 512 U.S. 504, 512 (1994)). And, as with conflicts
over statutory interpretation, it is the Secretary rather than
the Commission who deserves our deference when the two
differ over a regulation’s meaning. Id.; see Energy West
Mining Co. v. FMSHRC, 40 F.3d 457, 463–64 (D.C. Cir.
1994).
Excel argues that this ordinary rule of deference to an
agency’s regulatory interpretation should not apply to the
Secretary of Labor’s construction of the 1972 Joint Finding, a
finding that was made not by her but by the Secretary of the
Interior and the Secretary of HEW. Excel does not rest this
argument simply on the fact that the Secretary of Labor was
not involved in the promulgation of the Joint Finding. In-
deed, the company concedes that, as early as 1975, the
Secretary of the Interior interpreted the Joint Finding in the
same way the Secretary of Labor does now, and that the
latter has succeeded to the former’s role under the statute.
Excel Br. at 38; see Energy West, 40 F.3d at 460 n.1 (holding
that appellate review of mine regulations promulgated by the
Secretary of the Interior proceeds as if the regulations were
originally promulgated by the Secretary of Labor); see also
Amerada Hess Pipeline Corp. v. Fed. Energy Regulatory
Comm’n, 117 F.3d 596, 600–01 (D.C. Cir. 1997) (deferring to
FERC’s interpretation of a regulation promulgated by the
ICC before the ICC’s authority over oil pipelines was trans-
ferred to FERC). Rather, it is the Secretary of HEW’s
involvement in the Joint Finding, Excel says, that renders
Sturm, Ruger & Co., Inc. v. Chao, 300 F.3d 867, 872 (D.C. Cir. 2002)
(noting that the ‘‘administrative and judicial review procedures in
the OSH Act are nearly identical to those in the Mine Act’’ (internal
quotation marks omitted)).
9
deference to the Secretary of Labor’s interpretation unwar-
ranted.
It is true that we do not generally accord deference to one
agency’s interpretation of a regulation issued and adminis-
tered by another agency. See Amerada Hess, 117 F.3d at
600. But that does not help Excel here. The Mine Act
grants the Secretary of Labor the authority to ‘‘develop,
promulgate, and revise as may be appropriate, improved
mandatory health or safety standards,’’ 30 U.S.C. § 811(a),
and to enforce those standards by citing mine operators for
violations, id. § 814(a).5 It further provides that standards,
decisions, regulations, and determinations issued under the
Coal Act remain in effect until the Secretary of Labor revises
them. Id. § 961(b)(1), (c)(2). As we explained in Paralyzed
Veterans of America v. D.C. Arena LP, where we granted
deference to the Justice Department’s interpretation of a
regulation that was initially drafted by another agency but
subsequently adopted and administered by Justice:
We do not defer TTT to an administrative agency’s inter-
pretation of its regulation solely because its employees
are the drafters and presumably have superior knowl-
edge as to what they intendedTTTT [T]he doctrine of
deference is based primarily on the agency’s statutory
role as the sponsor of the regulation, not necessarily on
its drafting expertiseTTTT Under Chevron, an agency’s
interpretation of ambiguous statutory language is enti-
tled to deference because of the agency’s delegated au-
thority to administer the statute, and the same consider-
ation underlies deference to an agency’s interpretation of
its own regulation.
117 F.3d 579, 585 (D.C. Cir. 1997); see Amerada Hess, 117
F.3d at 601 (rejecting an argument that the court should deny
deference to FERC because that agency did not promulgate
the regulation at issue, noting that ‘‘[c]ourts defer to agency
5 The mandatory health standard that MSHA determined was
violated in this case — the standard for respirable coal dust codified
at 30 C.F.R. § 70.100(a) — was formally adopted by the Secretary
of Labor in 1980. See 45 Fed. Reg. at 23,995.
10
interpretations in large part because Congress has chosen to
delegate to the agency decisionmaking in the field’’). This
analysis applies here as well, and we therefore accord appro-
priate deference to the Secretary of Labor’s interpretation of
both the Mine Act and the 1972 Joint Finding.
Finally, in evaluating the reasonableness of the Secretary’s
interpretation of the statute and the Joint Finding, we take
into account the fact that her reading tracks both the Depart-
ment of the Interior’s and the Department of Labor’s original
interpretation, adopted at a time when the origins of both the
statute and the finding were fresh in the minds of their
administrators. Likewise, we give weight to the fact that the
agency that administers the statute and the Joint Finding has
interpreted them the same way for more than 25 years. See
Barnhart v. Walton, 535 U.S. 212, 220 (2002) (‘‘[T]his Court
will normally accord particular deference to an agency inter-
pretation of longstanding duration.’’ (internal quotation marks
omitted)).6
We now proceed to examine the validity of the Secretary’s
interpretation. We consider the question of statutory inter-
6 The history of this departmental interpretation is set forth at 63
Fed. Reg. at 5687–89, and is not contested by Excel, see Excel Br.
at 13; Joint Stip. at 3 (J.A. at 8). See also Excel Mining, 23
FMSHRC at 602; 65 Fed. Reg. at 42,072–73. Although the Secre-
tary has always read the statute and Joint Finding to permit
multiple single-shift sampling, from 1991–94 MSHA also conducted
a Spot Inspection Program at selected mines, under which a citation
was issued when a single full-shift measurement exceeded the
respirable dust standard by a specified amount. MSHA contended
that the Joint Finding did not bar the program because the finding
pertained to operator sampling, while the program involved MSHA
sampling only. The Commission, however, rejected that argument,
Secretary of Labor v. Keystone Coal Mines Corp., 16 FMSHRC 6
(1994), and MSHA terminated the program. See 63 Fed. Reg. at
5688; Mine Shift Atmospheric Conditions; Respirable Dust Sample,
62 Fed. Reg. 68,372, 68,375 (Dec. 31, 1997) (describing Spot Inspec-
tion Program); Joint Stip. at 3 (J.A. at 8) (stipulating that each
citation in Keystone was based on a single sample).
11
pretation in Part III and that of regulatory interpretation in
Part IV.
III
Excel contends that this case is resolved by a simple
application of Chevron’s first step. According to the compa-
ny, Mine Act § 202(f) unambiguously requires the Secretary
to use multiple-shift samples to measure respirable dust, and
bars her from using any kind of single-shift methodology. By
contrast, the Secretary argues that the case is resolved by
Chevron’s second step, because the language of the Act is
ambiguous on this question and her construction is reason-
able. According to the Secretary, the Mine Act permits her
to use either multiple-shift samples or multiple single-shift
samples to calculate average dust concentration for enforce-
ment purposes. The only kind of measurement that is
barred, in her view, is the use of a single full-shift sample —
which measures a single miner’s exposure over a single shift.
The starting place for our analysis is Mine Act § 202(b)(2),
originally part of the Coal Act, which sets the initial exposure
standard for respirable dust. That section requires that each
mine operator ‘‘continuously maintain the average concentra-
tion of respirable dust in the mine atmosphere during each
shift to which each miner in the active workings of such mine
is exposed at or below 2.0 milligrams of respirable dust per
cubic meter of air.’’ 30 U.S.C. § 842(b)(2) (emphasis added).
Needless to say, the language of this section does not unam-
biguously resolve this dispute, as all three methodologies at
issue here involve the use of ‘‘averages’’: Excel’s multiple-
shift method averages results over several shifts; the Secre-
tary’s multiple single-shift method averages results over a
single shift; and the single full-shift method calculates the
average exposure of a single miner over an entire shift. See
supra note 2.
We next turn to Mine Act § 202(f), which defines ‘‘average
concentration’’ for purposes of § 202(b) and which is the
statutory provision at the heart of this litigation. The first
part of § 202(f) contains a definition that, both parties agree,
12
effectively required the Secretary to use the multiple-shift
method for the first 18 months after passage of the Coal Act,
a period that began on December 30, 1969, and ended in 1971.
See 30 U.S.C. § 842(f)(1). Thereafter, § 202(f) defines ‘‘aver-
age concentration’’ as:
a determination which accurately represents the atmo-
spheric conditions with regard to respirable dust to
which each miner in the active workings of a mine is
exposed TTT (2) as measured TTT, over a single shift only,
unless the Secretary [of Labor; originally, the Secretary
of the Interior] and the Secretary of Health and Human
Services [originally, the Secretary of HEW] find, in
accordance with the provisions of section 811 of this title,
that such single shift measurement will not, after apply-
ing valid statistical techniques to such measurement,
accurately represent such atmospheric conditions during
such shift.
30 U.S.C. § 842(f) (emphasis added). Although they disagree
as to its meaning, see infra Part IV, both parties agree that
the 1972 Joint Finding is the finding contemplated in § 202(f),
and neither party questions its validity. Our statutory con-
struction therefore proceeds on that assumption. See supra
note 3.
Excel contends that there is only one way to read § 202(f):
because the section requires measurement ‘‘over a single shift
only’’ unless the Secretaries make a joint finding, and because
the Secretaries made such a finding, measurements over a
single shift — however they are made — are barred. This is
certainly a plausible reading. But the Secretary’s arguments
persuade us that such an interpretation is not unambiguously
required, and that her reading is at least a reasonable one.
To begin, we note that although § 202(f) uses the phrase
‘‘over a single shift only,’’ the subsection thereafter refers to
that methodology as ‘‘such single shift measurement.’’ See 30
U.S.C. § 842(f). The Secretary points out that this reference
phrase introduces at least two ambiguities. First, if one
emphasizes the word ‘‘single,’’ the result suggests that while
Congress was concerned that a ‘‘single shift measurement’’
13
might not ‘‘accurately represent TTT atmospheric conditions
during [a] shift,’’ the legislature was not necessarily con-
cerned about the use of multiple measurements — whether
taken over a single shift or over several.7 This reading is not
unreasonable.
A second ambiguity in the same reference phrase arises
from its use of the singular ‘‘measurement,’’ rather than the
plural ‘‘measurements.’’ See 30 U.S.C. § 842(f). The use of
the singular, the Secretary argues, can reasonably be inter-
preted as referring to the taking of a single as opposed to
multiple samples, even over a single shift. This ambiguity is
reinforced by a second use of the singular noun ‘‘measure-
ment,’’ as well by the preceding term ‘‘each miner’’ instead of
‘‘miners.’’ See id. Two members of the Commission rejected
this argument on the basis of a canon of statutory construc-
tion providing that ‘‘terms written in the singular generally
include the plural.’’ Excel Mining, 23 FMSHRC at 606
(Riley and Verheggen, Comm’rs). But to say that the singu-
lar ‘‘generally’’ includes the plural acknowledges that there
are exceptions, and hence that the singular can be ambiguous.
Indeed, Excel’s own brief implicitly recognizes the ambiguity
of the singular, arguing that ‘‘the term ‘measurement’ can be
both singular and plural in meaning.’’ Excel Br. at 28
(emphasis added).
There are also two ambiguities embedded in the phrase ‘‘as
measured TTT, over a single shift only, unless the Secre-
tar[ies] TTT findTTTT’’ 30 U.S.C. § 842(f). The first ambigui-
ty stems from the statute’s use of the word ‘‘only.’’ The
Secretary observes that although this means that she must
measure dust over a single shift if there is no finding, the
implication is that if there is a finding (as there is here) she is
not restricted to single-shift measurement only but instead
has her choice of single- or multiple-shift measurement. The
second ambiguity has its source in the word ‘‘unless.’’ The
Secretary notes that while the word clearly restricts her to
single-shift measurement in the absence of a finding, the
7 This ambiguity can also be highlighted by the use of a hyphen:
to the Secretary’s eyes, the reference phrase reads ‘‘single shift-
measurement,’’ not ‘‘single-shift measurement.’’
14
section is silent as to what she must do if a finding is made.
In light of that silence, we must accord deference to any
reasonable construction proffered by the Secretary. See
Chevron, 467 U.S. at 843. And it is not unreasonable for her
to conclude that without an express restriction she is free to
use whichever of the two methodologies — multiple single-
shift sampling or multiple-shift sampling — she thinks most
appropriate for a particular mine.
The Secretary also persuades us that her interpretation is
reasonable in light of the role that § 202(f) plays in the Mine
Act, which is to provide a definition for the term ‘‘average
concentration’’ as used in § 202(b).8 The Secretary notes
that the purpose of the latter section is to ensure that ‘‘each
operator shall continuously maintain the average concentra-
tion of respirable dust in the mine atmosphere during each
shift to which each miner in the active workings of such mine
is exposed at or below 2.0 milligrams of respirable dust per
cubic meter of air.’’ 30 U.S.C. § 842(b)(2) (emphasis added).
A single full-shift sample may not accomplish this purpose,
she argues, because it measures the exposure of only one
miner — whose exposure may be different from that of other
miners performing different jobs on the same shift — while
the statute requires protection for ‘‘each’’ miner. As a conse-
quence, she postulates, it is logical to conclude that it was the
statistical accuracy of single full-shift sampling that was the
object of Congress’ concern in § 202(f)(2).
8 Although both sides further urge us to rely upon the legislative
history of § 202(f), we find little there that is useful. The original
House bill was apparently intended to require the use of multiple
shift sampling for compliance determinations, although it did not
use those words. See H. REP. NO. 91–563, at 15 (1969). By
contrast, the Senate bill was apparently intended to bar multiple
shift sampling, although it also did not employ those words. See S.
REP. NO. 91–411, at 20 (1969). Section 202(f) appears to have been a
compromise, mandating multiple shift sampling for the first 18
months and single shift measurement thereafter unless the Secre-
taries found such measurement to be statistically inaccurate. But
nothing in the legislative history explains what Congress meant by
‘‘single shift measurement.’’
15
But, the Secretary continues, she also cannot accomplish
the statutory purpose of ensuring that the average concentra-
tion of respirable dust ‘‘during each shift’’ is at or below 2.0
mg/m3 if she is restricted — as Excel insists she is — to
averaging samples taken over multiple shifts. As the Secre-
tary explains, a multiple-shift average may mask a high
concentration on a particular shift: for example, an above-
threshold sample collected on the first shift, averaged with
sub-threshold samples collected on subsequent shifts, may
yield a sub-threshold average — even though each miner on
the first shift is exposed to more than 2.0 mg/m3. See 63 Fed.
Reg. at 5688. Data collected by MSHA during the course of
its Spot Inspection Program reveals that this is not a hypo-
thetical problem.9 And it is not unreasonable to infer, as the
Secretary does, that Congress did not intend to require her to
use a methodology (multiple-shift sampling) that is incompati-
ble with the legislature’s purpose of ensuring that the average
concentration of respirable dust ‘‘during each shift’’ remains
below the designated threshold.
Excel responds that the Secretary’s method has masking
problems of its own. Basing compliance on the average of
multiple samples taken over a single shift may hide the high
dust exposure of a particular miner on that shift. And if the
shift is not well chosen, this method may also mask an above-
threshold exposure on another shift. The Secretary does not
9 MSHA describes the data as follows:
[T]he initial full-shift samples collected by an inspector are
likely to show higher dust concentrations than succeeding
samples collected on subsequent shifts during the same inspec-
tion. MSHA’s data showed that the average concentration of
all samples taken on the same occupation on the first day of an
inspection was almost twice as high as the average concentra-
tion of those taken on the second day.
63 Fed. Reg. at 5688. MSHA explains that such subsequent,
unrepresentative measurements ‘‘would arise if mine operators
anticipated the continuation of inspector sampling and made adjust-
ments in dust control parameters or production rates to reduce dust
levels during the subsequent monitoring.’’ Id.
16
dispute these possibilities. But she also does not read the
Mine Act as limiting her to the use of multiple samples over a
single shift. Rather, she believes that she also retains discre-
tion to use multiple samples over multiple shifts. She in-
tends, she says, to choose the method that best protects
miners under the conditions in a particular mine. Where the
problem is variance in the quantity of atmospheric dust within
a shift, she may well choose Excel’s preferred method —
multiple-shift sampling — concentrating on miners who are
working in an occupation with the highest dust exposure.10
But where there is significant variance between shifts, she
may instead choose to take multiple samples over a single
shift, focusing on the shift with the highest concentration of
dust.
Excel asserts that, notwithstanding this administrative flex-
ibility, multiple single-shift sampling is ‘‘especially unreliable’’
as an indicator of the respirable dust levels to which individu-
al miners are exposed, and is thus inadequate to protect
miners’ health. Excel Br. at 24. The Commission similarly
describes the methodology as ‘‘ill-advised.’’ Excel Mining, 23
FMSHRC at 608 (Riley and Verheggen, Comm’rs). Needless
to say, the Secretary disagrees — as does the United Mine
Workers union, which filed an amicus brief in support of the
Secretary. This court lacks the experience and expertise to
10The Secretary’s longstanding multiple single-shift sampling
methodology employed the following corrective for intra-shift vari-
ance:
The mine operator was cited if the average of all measurements
obtained during the same shift exceeded the applicable stan-
dardTTTT If one or more measurements exceeded the applica-
ble standard but the average did not, the Agency’s practice was
to continue sampling for up to four additional production shifts
or days. If the inspector continued sampling after the first day
because a previous measurement exceeded the applicable stan-
dard, noncompliance determinations were based on either the
average of all measurements taken or on the average of
measurements taken on any one occupation.
63 Fed. Reg. at 5687.
17
resolve that methodological dispute. But more to the point,
we lack the authority to do so. When ‘‘a challenge to an
agency construction of a statutory provision, fairly conceptu-
alized, really centers on the wisdom of the agency’s policy,
rather than whether it is a reasonable choice within a gap left
open by Congress, the challenge must fail.’’ Chevron, 467
U.S. at 866; see also Cannelton Indus., 867 F.2d at 1435.
In sum, we conclude that the statutory language is ambigu-
ous and that the Secretary’s interpretation is reasonable.
And we decline to second-guess the Secretary’s longstanding
view that taking multiple samples over both single and multi-
ple shifts is a reasonable and effective means of effectuating
the purpose of the Mine Act.11
IV
We turn next to the 1972 Joint Finding. In light of our
affirmation of the Secretary’s interpretation of Mine Act
§ 202(f), and because the parties dispute neither the validity
of that finding nor the fact that its promulgation triggers the
consequences contemplated by § 202(f)(2), the finding itself
does not have great independent significance for our analysis.
Nonetheless, our review confirms that it is reasonably read —
11 In its brief in this court, Excel argues that, even if Mine Act
§ 202(f)(2) does not preclude the Secretary from using multiple
samples over a single shift, the citations issued against the company
are still invalid because the Act contains no affirmative authoriza-
tion for the Secretary to use such samples to determine compliance
with mandatory health standards. The Secretary responds that the
necessary authority is provided by Mine Act §§ 103(a) and 202(g).
See 30 U.S.C. §§ 813(a), 842(g). Although it appears that the
Secretary has the better of the argument, see generally Chao v.
Rothermel, 327 F.3d 223, 225–27 (3d Cir. 2003) (describing the
‘‘ample authority’’ provided by §§ 103(a) and 202(g)), we do not
consider its merits because Excel failed to raise it before the
Commission and offers no excuse for not doing so. See 30 U.S.C.
§ 816(a) (‘‘No objection that has not been urged before the Com-
mission shall be considered by the court, unless the failure or
neglect to urge such objection shall be excused because of extraor-
dinary circumstances.’’).
18
as the Secretary urges — as a determination that single full-
shift sampling is an inaccurate methodology for measuring
exposure to respirable dust, while expressing no opinion
regarding the accuracy of taking multiple samples over a
single shift.
As we said in Part II, we must uphold the Secretary of
Labor’s interpretation ‘‘ ‘unless it is plainly erroneous or
inconsistent with the regulation.’ ’’ Akzo Nobel, 212 F.3d at
1303 (quoting Thomas Jefferson Univ., 512 U.S. at 512). We
also take notice of the facts that: (1) as early as 1975, the
Secretary of the Interior, who joined in making the finding in
1972, interpreted it just the way the Secretary of Labor does
now; and (2) the agency that administers the section has
consistently interpreted it that same way for more than 25
years. See Barnhart, 535 U.S. at 219–20.
The Joint Finding states in pertinent part:
Pursuant to section 202(f) of the Federal Coal Mine
Health and Safety Act of 1969 TTT, there was published
in the FEDERAL REGISTER TTT a proposed notice of finding
by the Secretary of the Interior and the Secretary of
Health, Education, and Welfare that single shift mea-
surement of respirable dust will not, after applying valid
statistical techniques to such measurement, accurately
represent the atmospheric conditions to which the miner
is continuously exposedTTTT After careful consideration
of all comments, suggestions, and objections, it is the
conclusion of the Secretary of the Interior and the Secre-
tary of Health, Education, and Welfare thatTTTT [t]he
proposed finding TTT that a measurement of respirable
dust over a single shift only, will not, after applying valid
statistical techniques to such measurement, accurately
represent the atmospheric conditions to which the miner
under consideration is continuously exposed, is hereby
adopted without change.
37 Fed. Reg. at 3833–34 (emphasis added). The Secretary
points out that, like the statute, the Joint Finding is written
in the singular. It states that ‘‘a measurement of respirable
dust over a single shift only will not TTT accurately represent
19
the atmospheric conditions to which the miner under consid-
eration is continuously exposed.’’ Id. at 3834. Although
Excel reasonably argues that an average can itself be consid-
ered a ‘‘measurement,’’ and that the term ‘‘the miner’’ can be
read as referring to miners in general, we cannot declare
unreasonable the Secretary’s view that all the Joint Finding
determined was that ‘‘a’’ single ‘‘measurement’’ of a particular
‘‘miner’’ was an insufficiently accurate methodology. This
construction therefore leaves it open to the Secretary to
measure compliance based on an average of multiple samples
taken over a single shift — a methodology that involves more
than one measurement taken from more than one miner. 63
Fed. Reg. at 5687.
The Secretary’s interpretation is also supported by lan-
guage in the proposed notice of finding that preceded (and
was adopted in) the Joint Finding. That notice described the
statistical work undertaken in support of the proposed finding
as follows:
In April 1971, a statistical analysis was conducted by the
Bureau of Mines, using as a basis the current basic
samples for the 2,179 working sections in compliance
with the dust standard on the date of the analysisTTTT
The results TTT show[ed] that a single shift measurement
would not, after applying valid statistical techniques,
accurately represent the atmospheric conditions to which
the miner is continuously exposed.
Notice of Finding That Single Shift Measurements of Respir-
able Dust Will Not Accurately Represent Atmospheric Condi-
tions During Such Shift, 36 Fed. Reg. 13,286, 13,286 (July 17,
1971) (emphasis added).12 As interpreted by the Secretary,
this passage explains that the basis for the Joint Finding was
a statistical analysis showing that ‘‘a’’ single ‘‘measurement’’
12Excel correctly notes that the title of the 1971 proposed notice
employed the plural, ‘‘Single Shift Measurements.’’ See 36 Fed.
Reg. at 13,286 (emphasis added). This does not erase or resolve
the ambiguity, however, since the title of the 1972 Joint Finding
used the singular, ‘‘a Single Shift Measurement.’’ 37 Fed. Reg. at
3833 (emphasis added).
20
was not an accurate way to represent atmospheric conditions.
See also Excel Mining, 23 FMSHRC at 607 (Riley and
Verheggen, Comm’rs) (‘‘The focus of the [1972] Finding is on
the reliability of discrete single shift measurements. By
comparing the results of many such single shift samples, the
Secretaries determined the statistical reliability of any given
sample, and found that, statistically speaking, any given
single shift sample was not reliable.’’). It is therefore fair to
infer that the Joint Finding was intended to preclude only
that kind of measurement.
In sum, the Joint Finding is at least as ambiguous as
§ 202(f), and because its wording is similar to that of the
statute, our conclusion is the same: the Secretary’s interpre-
tation is reasonable.
V
The questions of interpretation posed by this petition are
difficult — largely because of the complicated syntax of the
statutory and regulatory language. On balance, however, we
think that the Secretary’s longstanding interpretation is rea-
sonable, and because that is all that is necessary for her view
to prevail, we grant the petition for review and reverse the
decision of the Commission.
So ordered.
1
SENTELLE, Circuit Judge, dissenting: The majority accu-
rately sets forth the background in this case and the appro-
priate standard of review. I do not believe it properly applies
that standard to those facts. As the majority reminds us,
courts ‘‘must give effect to the unambiguously expressed
intent of Congress.’’ Chevron U.S.A. Inc. v. Natural Res.
Def. Council, Inc., 467 U.S. 837, 843 (1984). The two-step
Chevron analysis comes into play only when ‘‘the statute is
silent or ambiguous with respect to the specific issue’’ under
review. Id. As I understand the specific issue before us, it
is whether the Secretary may make the determination of
average concentration more than eighteen months after De-
cember 30, 1969, by measurement over a single shift after a
finding that ‘‘single shift measurement of respirable dust will
not, after applying valid statistical techniques to such mea-
surement, accurately represent the atmospheric conditions to
which the miner is continuously exposed.’’ Notice of Finding
that a Single Shift Measurement of Respirable Dust Will Not
Accurately Represent Atmospheric Conditions During Such
Shift, 37 Fed. Reg. 3833 (Feb. 23, 1972).
The statute passed by Congress says that after that trigger
date, the average concentration is ‘‘as measured TTT over a
single shift only, unless the Secretar[ies] find TTT that such
single shift measurement will not TTT accurately represent
such atmospheric conditions during such shift.’’ 30 U.S.C.
§ 842(f). I am aware, as we have observed in the past, that
‘‘some will find ambiguity even in a ‘No Smoking’ signTTTT’’
Int’l Union, United Auto. Aerospace & Agric. Implement
Workers of America v. General Dynamics Land Sys. Div.,
815 F.2d 1570, 1575 (D.C. Cir. 1987). I see no more ambigui-
ty on the specific issue in this case than in a ‘‘No Smoking’’
sign. Single shift measurement is to be used unless the
finding is made. Here the finding has been made. I do not
see how the statute can be read as authorizing the use of
single shift measurement.
Obviously since I find no ambiguity, I would not reach the
second step of Chevron to pursue the reasonableness of the
interpretation. However, as the majority does reach that
step, I will comment briefly upon it. The question at that
2
second step is: whether the administrative interpretation is a
‘‘permissible construction of the statute,’’ Chevron, 467 U.S.
at 843. A permissible construction to which we must defer is
‘‘a reasonable interpretation made by the administrator of
[the] agency.’’ Id. at 844. I not only do not find the
Secretary’s construction of the statute to be a reasonable one,
I am not at all certain what the construction is. After
reviewing the record before us and the opinion of the majori-
ty, I am still at a loss to understand how the Secretary
construes the words of 30 U.S.C. § 842(f) to allow the use of
single shift measurement after the adverse finding has been
made.
I agree with the majority that the syntax of the statute and
the regulation are complicated. This has perhaps created a
problem of interpretation. But the resolution of that problem
is for Congress, not the Secretary or the court. I understand
the Secretary is pursuing the laudable goals set forth by
Congress ‘‘to provide, to the greatest extent possible, that the
working conditions in each underground coal mine are suffi-
ciently free of respirable dust concentrations in the mine
atmosphere to permit each miner the opportunity to work
underground during the period of his entire adult working life
without incurring any disability from pneumoconiosis or any
other occupation related disease during or at the end of such
period.’’ 30 U.S.C. § 841(b). But as we have observed
before, the congressional motivation in a statute, no matter
how exemplary, does not issue to the administrative agency
‘‘a roving commission to achieve [any] laudable goal.’’ Michi-
gan v. EPA, 268 F.3d 1075, 1084 (D.C. Cir. 2001). Any
federal agency’s authority must be derived from the statute
under which it operates, and unless it is within that portfolio,
the agency’s acts, no matter how reasonable or beneficent,
are not consistent with law. In my view, the Secretary here
has overstepped that statutory empowerment. I therefore
respectfully dissent.