Document ID: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-caDC-01-01335/USCOURTS-caDC-01-01335-0/pdf.json

Parties Involved:
Excel Mining, LLC
Respondent
Federal Mine Safety and Health Review Commission
Respondent
Secretary of Labor
Petitioner

Document Text:

Notice: This opinion is subject to formal revision before publication in the

Federal Reporter or U.S.App.D.C. Reports. Users are requested to notify

the Clerk of any formal errors in order that corrections may be made

before the bound volumes go to press.

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 support 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.

USCA Case #01-1335 Document #758650 Filed: 07/08/2003 Page 1 of 22
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 respirable coal dust by using a methodology that averages multiple

dust samples taken over a single shift. In 1999, the Secretary 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 Secretary’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, metals, and non-metals under the same regulatory scheme and

transferred enforcement powers and other duties from the

USCA Case #01-1335 Document #758650 Filed: 07/08/2003 Page 2 of 22
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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 Secretary 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 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 [‘‘black lung’’ disease] or any other occupation-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 milligrams of respirable dust per cubic meter of air.

30 U.S.C. § 842(b)(2) (emphasis added). The current mandatory 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 determination which accurately represents the atmospheric conditions 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 DecemUSCA Case #01-1335 Document #758650 Filed: 07/08/2003 Page 3 of 22
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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 Secretary of Health and Human Services [originally, the Secretary 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 Accurately 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 atmosphere of each underground mine ‘‘in its entirety’’ at least

four times annually. 30 U.S.C. § 813(a). If ‘‘upon inspection

1 The 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).

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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 determinations under the respirable dust standard on the average

of multiple measurements taken over a single shift. See Coal

Mine Respirable Dust Standard Noncompliance Determinations, 63 Fed. Reg. 5687, 5687 (Feb. 3, 1998); Joint Stipulations 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 exceeded 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 limited 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

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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 measurements 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 commissioner agreed with the Secretary that the Joint Finding was

ambiguous on the question, but concluded that the Secretary’s interpretation was unreasonable on policy grounds. Id.

at 614 (Beatty, Comm’r, concurring).3

 Exercising her statu2 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 methodologies discussed here — single full-shift sampling, multiple singleshift 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).

USCA Case #01-1335 Document #758650 Filed: 07/08/2003 Page 6 of 22
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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 lawmaking 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

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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 interpretation ‘‘ ‘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. Indeed, 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 transferred 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)).

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deference to the Secretary of Labor’s interpretation unwarranted.

It is true that we do not generally accord deference to one

agency’s interpretation of a regulation issued and administered 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 interpretation of its regulation solely because its employees

are the drafters and presumably have superior knowledge 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 entitled to deference because of the agency’s delegated authority to administer the statute, and the same consideration 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.

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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 appropriate 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 Department 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 interpretation 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 inter6 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 Secretary 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 Inspection Program); Joint Stip. at 3 (J.A. at 8) (stipulating that each

citation in Keystone was based on a single sample).

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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 company, 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 reasonable. 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 enforcement 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 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 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 unambiguously resolve this dispute, as all three methodologies at

issue here involve the use of ‘‘averages’’: Excel’s multipleshift method averages results over several shifts; the Secretary’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,

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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 ‘‘average concentration’’ as:

a determination which accurately represents the atmospheric 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 applying 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 construction 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’’

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might not ‘‘accurately represent TTT atmospheric conditions

during [a] shift,’’ the legislature was not necessarily concerned 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 interpreted 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 ‘‘measurement,’’ 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 construction 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 singular ‘‘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 Secretar[ies] TTT findTTTT’’ 30 U.S.C. § 842(f). The first ambiguity 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 shiftmeasurement,’’ not ‘‘single-shift measurement.’’

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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 singleshift 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 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 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 consequence, 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 Secretaries found such measurement to be statistically inaccurate. But

nothing in the legislative history explains what Congress meant by

‘‘single shift measurement.’’

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But, the Secretary continues, she also cannot accomplish

the statutory purpose of ensuring that the average concentration 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 Secretary explains, a multiple-shift average may mask a high

concentration on a particular shift: for example, an abovethreshold 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 hypothetical 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 incompatible 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 abovethreshold 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 inspection. 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 concentration 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 adjustments in dust control parameters or production rates to reduce dust

levels during the subsequent monitoring.’’ Id.

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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 discretion to use multiple samples over multiple shifts. She intends, 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 flexibility, multiple single-shift sampling is ‘‘especially unreliable’’

as an indicator of the respirable dust levels to which individual 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

10 The Secretary’s longstanding multiple single-shift sampling

methodology employed the following corrective for intra-shift variance:

The mine operator was cited if the average of all measurements

obtained during the same shift exceeded the applicable standardTTTT If one or more measurements exceeded the applicable 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 standard, 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.

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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 conceptualized, 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 ambiguous 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 multiple 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 authorization 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 Commission shall be considered by the court, unless the failure or

neglect to urge such objection shall be excused because of extraordinary circumstances.’’).

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as the Secretary urges — as a determination that single fullshift 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 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 exposedTTTT After careful consideration

of all comments, suggestions, and objections, it is the

conclusion of the Secretary of the Interior and the Secretary 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

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19

the atmospheric conditions to which the miner under consideration is continuously exposed.’’ Id. at 3834. Although

Excel reasonably argues that an average can itself be considered 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 language 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 Respirable Dust Will Not Accurately Represent Atmospheric Conditions 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’’

12 Excel 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).

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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 interpretation 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 reasonable, 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.

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SENTELLE, Circuit Judge, dissenting: The majority accurately sets forth the background in this case and the appropriate 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 December 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 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

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 ambiguity 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

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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 majority, 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 sufficiently 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.’’ Michigan 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.

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