Consolidation Coal Company petitions the court for review of a decision of the Mine Safety and Health Review Commission upholding a citation by the Mine Safety and Health Administration (MSHA) for failure to ensure that any of its miners could at all times see a warning signal mounted on a methane monitor in one of its mines, in contravention of 30 C.F.R. § 75.342(b)(2). Consolidation concedes that its miners could not see the warning signal at all times, but contends that because its mine automatically shut down whenever the methane levels reached the point where the warning signal was to be triggered, it was in compliance with the regulation. Mindful of the substantial deference we owe the Secretary in the interpretation of her own regulations, we deny the petition for review.
Í.
In the Federal Mine Safety and Health Act of 1977 (the “Mine Act”), 30 U.S.C. §§ 801 et seq- (1988), Congress directed the Secretary of Labor to “develop, promulgate, and revise as may be appropriate, improved mandatory health or safety standards for the protection of life and prevention of injuries in coal ... mines.” 30 U.S.C. § 811(a) (1988). Concerned about the accumulation of methane gas and ignition sources that could spark explosions, Congress directed the Secretary to require that mine operators install monitors “for detecting concentrations of methane” on “any electric face cutting equipment,” including “longwall face equipment.” 30 U.S.C. § 863©. Pursuant to this congressional delegation, the Secretary of Labor has promulgated regulations requiring the installation of methane monitors on, inter alia, “all ... longwall face equipment.” 30 C.F.R. § 75.342(a)(1) (1997). The Secretary requires each of the methane monitors to include a warning signal. In 1994, the regulations provided:
(1) When the methane concentration at any methane monitor reaches 1.0 percent the monitor shall give a warning signal.
(2) The warning signal device of the methane monitor shall be visible to a person who can deenergize the equipment on which the monitor is mounted.
30 C.F.R. § 75.342(b) (1994). 1 The Secretary at that time also required all longwall machinery to shut down when the methane concentration in the mine reached 2.0%. 30 C.F.R. § 75.342(c) (1994). 2
Consolidation uses the longwall mining system to extract coal from its Robinson Run No. 95 mine in West Virginia. A longwall is created by digging two parallel, vertical tunnels and a third horizontal connector tunnel.
See International Union, United Mine Workers v. FMSHA,
Longwall face 2-D in Consolidation’s West Virginia mine contains two methane sensors, placed at the middle and one end (the “tailgate”) of the longwall. These sensors are *821 connected to a methane monitor located at the other end of the longwall (the “head-gate”). The monitor contains a panel with a yellow warning light that flashes when methane reaches a level of 1.0% of the atmosphere as well as a red “trip light” that will activate at the same time. It also contains two digital displays that provide readouts of the methane levels along the longwall face. Whenever the warning lights are triggered, the lighting on petitioner’s longwall face goes out and all the equipment electrically connected to the longwall automatically deenergizes, with the exception of the methane monitors and face telephone system. 3 In this way, Consolidation’s mine automatically shuts down before federal regulations require it to do so, at 1.0% methane, rather than at 2.0% methane. See 30 C.F.R. § 75.342(c)(1) (1997).
After promulgating section 75.342(b), MSHA inspectors notified Consolidation seven times that its mine did not comply with the regulation. In 1993, MSHA sent two letters to Consolidation discussing the regulation’s visibility requirements. The company took no action in response to the letters and warnings. On April 19, 1994, a MSHA inspector visited Consolidation’s West Virginia mine. The inspector could not see the warning lights on the system’s methane monitor from the position of the “headgate operator,” who was the miner closest to the monitor. The monitor was located approximately thirty feet from the place where the head-gate operator would shovel spilled coal onto the conveyor belt that took the coal to the surface. Accordingly, the MSHA inspector issued a citation for failure to comply with section 75.342(b)(2).
Consolidation contested the citation, and an Administrative Law Judge vacated it. Although there was no doubt that the headgate operator could not see the warning lights of the methane monitor at all times, the judge concluded that the deenergization of the longwall mining equipment and nearby lighting when the methane level reached 1.0% constituted a “visible signal to the headgate operator and other miners authorized to deenergize the longwall ... that methane may have reached 1.0%,” as required by section 75.342(b)(2).
Consolidation Coal Co. v. Secretary of Labor,
the headgate operator [then] must return to the master control box to restart the power. When the operator arrives at the control box after a methane shutdown, he will be confronted by computer [sic] display’ that will advise him in plain english [sic] that there has been a “methane monitor fault.”
Id. at 1243-44 (citations omitted).
The Secretary appealed to the Commission, arguing that the “evidence was undisputed that the warning signal device on the methane monitor was not visible to a person who could deenergize the longwall,” and that that fact was determinative of noncompliance with section 75.342(b)(2).
Consolidation Coal Co. v. Secretary of Labor,
II.
Whether Consolidation’s methane monitoring system complies with section 75.342(b)(2) turns on the Secretary’s analysis of the regulation that was accepted by the Commission. “We accord great deference to interpretations ... advanced by the Secretary and accepted by the Commission.”
Energy West Mining Co. v. FMSHRC,
Contrary to Consolidation’s contention, we conclude, first, that the Secretary’s interpretation of section 75.342(b) does not conflict with its plain meaning. Under the Secretary’s interpretation, the monitor warning signal at all times must be visible to a miner who could respond if the light is triggered by a concentration of 1.0% methane on the long-wall face. The interpretation requires not just a warning signal, but a signal that is a “device of’ the methane monitor and a signal that is visible at all times to a miner who can react to increasing methane levels and, if necessary, deenergize the mining equipment. Through this interpretation, the Secretary has appropriately construed section 75.342(b) to give effect to all of its provisions.
Cf. Otis Elevator Co. v. Secretary of Labor,
Consolidation contends that its methane monitoring device could also comport with section 75.342(b)(2). But this alternate reading is not compelled by the regulation.
See Thomas Jefferson Univ.,
Nor did the Secretary intend to cover methane monitoring devices like the one located in Consolidation’s mine when she promulgated section 75.342(b)(2).
See Gardebring,
paragraph (b)(2) requires the warning signal device of the methane monitor to be visible to a person capable of deenergizing the equipment on which the monitor is mounted. This allows the operator of the face equipment, or other person, to deen-ergize the equipment at 1.0 percent, if necessary.
57 Fed.Reg. 20,868, 20,891 (May 15, 1992). The Secretary’s explanation does not suggest any expansive intent to cover visible warning
*823
signals not covered by the plain language of the regulation. Consolidation offers no evidence that the Secretary has ever adopted a different interpretation of the regulation, or that she has contradicted her position on appeal.
See National Wildlife Fed’n v. Browner,
Consolidation, and the dissenting commissioner,
see Consolidation Coal Co.,
Early deenergization of the longwall upon the detection of 1.0% methane may well have its own,safety advantages. As the Tenth Circuit has explained, “[ajutomatic deenergization prevents the electrical equipment from sparking, which could ignite the gas and result in an explosion.”
Ayala v. United States,
Accordingly, we deny the petition for review.
Notes
. The regulations do not differ in any relevant way today. See 30 C.F.R. § 75.342(b) (1997).
. In 1994, 30 C.F.R. § 75.342(c) provided:
The methane monitor shall automatically deen-ergize-, the machine on which it is mounted when—
(1) The methane concentration at any methane monitor reaches 2.0 percent; or
(2) The monitor is not operating properly.
. According to the parties' briefs, to a person standing where the headgate operator was, automatic deenergization appears virtually identical to a power outage.
. The word "of” is "used as a function word to indicate the material, parts, or elements composing something or the contents held by something.” Webster's Third New International Dictionary Unabridged 1565 (1981). The longwall machinery is not an element of the methane monitor.
. The term “device” means “a piece of equipment or a mechanism designed to serve a special purpose or perform a special function.” Webster's Third New International Dictionary Unabridged. 618 (1981). The longwall machinery in this sense is not a device meant to warn the headgate operator that methane levels have reached 1.0%. Its special purpose or function is not to issue methane level warnings. The machinery instead mines coal, and was installed along the longwall for that purpose.
. The Mine Act provides:
Upon petition by the operator ... the Secretary may modify the application of any mandatory safety standard to a coal or other mine if the Secretary determines that an alternative method of achieving the result of such standard exists which will at all times guarantee no less than the same measure of protection afforded the miners of such mine by such standard ....
30U.S.C. § 811(c).
