The opinion of the court was delivered by: Rogers, Circuit Judge
On Petitions for Review of an Order of the Federal Mine Safety & Health Administration.
Before: ROGERS and TATEL, Circuit Judges, and WILLIAMS, Senior Circuit Judge.
The National Mining Association ("NMA") and the Methane Awareness Resources Group ("MARG") (hereinafter, together "industry") petition for review of the Mine Safety and Health Administration's ("MSHA's") decision to enforcea final exposure limit standard addressing health risks presented by exposure of miners in metal and non-metal underground mines to diesel particulate matter ("DPM") in diesel exhaust. The decision, announced May 20, 2008, represented a change in MSHA's earlier expressed intent to issue a proposed rule to convert the final DPM exposure standard from a total carbon ("TC") to an elemental carbon ("EC") measurement. See Diesel Particulate Matter Exposure, Notice of Enforcement of DPM Final Limit and Withdrawal of Intent to Issue Proposed Rule, 73 Fed. Reg. 29,058 (May 20, 2008) ("2008 Notice"). On the same date, MSHA issued Program Policy Letter P08-IV-01 ("2008 Policy Letter") describing how it intended to enforce the DPM standard. Industry contends MSHA's decision was arbitrary and capricious because inadequately explained and unsupported by scientific data, contrary to a 2002 settlement and to MSHA's statements to this court, and without public notice or opportunity to comment. MARG individually challenges the failure of the National Institute of Occupational Safety and Health ("NIOSH") to release a study on DPM. For the reasons that follow, we deny the industry petitions and dismiss MARG's individual challenges for lack of jurisdiction.
The Mine Act provides that MSHA shall "develop, promulgate, and revise as may be appropriate, improved mandatory health or safety standards for the protection of life and prevention of injuries in coal or other mines." 30 U.S.C. § 811(a). For "toxic materials or harmful physical agents," MSHA "shall set standards which most adequately assure on the basis of the best available evidence that no miner will suffer material impairment of health or functional capacity" and, "[i]n addition to the attainment of the highest degree of health and safety protection for the miner, other considerations shall be the latest available scientific data in the field, the feasibility of the standards, and experience gained under this and other health and safety laws." Id. § 811(a)(6)(A). A new mandatory health or safety standard may not provide less protection to miners than an existing mandatory standard. Id. § 811(a)(9). A person adversely affected by a mandatory health or safety standard promulgated under section 811 may petition for judicial review of the standard within 60 days after the standard is promulgated. Id. § 811(d).
Based on an assessment of the risk to miners of adverse health effects from DPM, MSHA promulgated a rule in January 2001 limiting the airborne concentration of DPM in underground metal and non-metal mines. See Diesel Particulate Matter Exposure, 66 Fed. Reg. 5706 (Jan. 19, 2001) ("2001 Rule"). The 2001 Rule set both interim and final DPM concentration standards, using TC measurements as a surrogate for measuring DPM; the interim DPM standard was to take effect in July 2002. Id. at 5706--07, 5726--27. The concentration limits were expressed as the number of micrograms of TC per cubic meter of air. After several petitions for review of the 2001 Rule were filed (including petitions by NMA and MARG), MSHA entered into a settlement agreement in July 2002 postponing the effective date of the interim DPM standard of 400 TC from July 2002 to July 2003, and requiring MSHA to propose an expedited rulemaking to change the DPM surrogate from TC to EC; the pending petitions for review were to be dismissed upon completion of the expedited rulemaking. See Diesel Particulate Matter Exposure, 67 Fed. Reg. 47,296, 47,297--99 (July 18, 2002) ("2002 Settlement").
Thereafter MSHA revised the 2001 Rule twice. In 2005, based on scientific data showing a TC:EC ratio of 1.3:1 for converting EC measurements to TC measurements at certain TC concentrations, MSHA converted the interim DPM standard from 400 TC to 308 EC. See Diesel Particulate Matter Exposure, 70 Fed. Reg. 32,868, 32,870 (June 6, 2005) ("2005 Rule"). MSHA explained that although the scientific data indicated this single, constant conversion factor was appropriate at 400 TC, the data were not adequate to convert the final DPM standard of 160 TC to an EC measurement. Id.; see also Diesel Particulate Matter Exposure, Proposed Rule, 70 Fed. Reg. 53,280, 53,287 (Sept. 7, 2005) ("2005 Proposed Rule"). In 2006, MSHA postponed the effective date of the final DPM standard of 160 TC from January 2006 to May 20, 2008, and set an interim standard of 350 TC to become effective in January 2007. See Diesel Particulate Matter Exposure, 71 Fed. Reg. 28,924, 28,978 (May 18, 2006) ("2006 Rule"). MSHA reiterated that the scientific data were not adequate for converting the final DPM standard of 160 TC to EC and stated that it intended to consider the TC-to-EC conversion in a separate rulemaking. Id. at 28,976, 28,983.
In February 2007, this court upheld the 2001, 2005, and 2006 Rules setting DPM standards. In Kennecott Greens Creek Mining Co. v. MSHA, 476 F.3d 946 (D.C. Cir. 2007), the court rejected challenges to the sufficiency of evidence of health risk for miners from DPM and to compliance feasibility for mine operators, and concluded MSHA reasonably chose TC as a surrogate for measuring DPM in view of evidence of their tight correlation and the fact that MSHA has a reliable method for determining the amount of TC in a sample. Id. at 955. The court also rejected claims that MSHA was arbitrary and capricious in not converting to EC the interim DPM standard of 350 TC and the final DPM standard of 160 TC, as MSHA had done in 2005 for the interim DPM standard of 400 TC. The court observed that "MSHA has clearly stated in its rules that TC can still serve as a consistent and reliable surrogate for DPM as long as samples are taken in areas away from tobacco smoke and oil mist." Id. at 956. The court noted MSHA had stated it would initiate a new rulemaking regarding conversion of the final standard from TC to EC. The court concluded:
In sum, MSHA has concluded that EC is a better proxy for DPM than TC, but this does not automatically render the use of TC to be arbitrary and capricious.
Even though TC sampling is more difficult than EC sampling, MSHA has reasonably determined that TC can still be a reliable proxy for DPM as long as samples are taken in the proper manner. In any event, MSHA's rulemaking suggests that it has no intention of using TC as a stand alone proxy.
On May 20, 2008, MSHA gave public notice of its decision to enforce the final DPM standard of 160 TC and to withdraw its intent to propose a rule converting 160 TC to EC. 2008 Notice, 73 Fed. Reg. at 29,058--59. In the 2008 Notice, MSHA explained that the latest available scientific evidence did not identify a single, constant conversion factor for EC below 230 TC. Id. at 29,059. It referenced an article about a study of four underground mines (two stone mines and two metal mines), which stated that the correlation between TC and EC varies below 230 TC and that the TC:EC ratio is highly variable below 160 TC. J.D. Noll et al., Relationship between Elemental Carbon, Total Carbon, and Diesel Particulate Matter in Several Underground Metal/Non-metal Mines, 41 Envtl. Sci. & Tech. 710, 715 (2007) ("Noll-Bugarski Study"); see 2008 Notice, 73 Fed. Reg. at 29,059. It also referenced a consultant's report advising that because the Noll-Bugarski Study showed that the variability of the TC:EC ratio increases as DPM levels decrease, EC measurements would not be an appropriate surrogate for DPM at 160 TC; the report discussed four sampling strategies for enforcing the 160 TC standard. J. Kogut, Alternative Strategies for Enforcing a DPM Exposure Limit 1 (Sept. 2007) ("Kogut Report"); see 2008 Notice, 73 Fed. Reg. at 29,059--60. The 2008 Notice stated that MSHA would provide a "protocol for calculating a location specific adjustment" to a miner's personal sample based on TC and EC measurements. 73 Fed. Reg. at 29,059. On the same date, May 20, 2008, MSHA also ...