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Proposed Rule

Diesel Particulate Matter Exposure of Underground Miners

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Mine Safety and Health Administration (MSHA), Labor.


Proposed rule; availability of documents; request for comments.


We (MSHA) are reopening the rulemaking records of our proposed rules on diesel particulate matter exposure of underground coal miners and underground metal and nonmetal miners. The reopenings are limited in scope. Their purpose is to permit public comment on a few recent documents that we have added to these records, including some agency investigations to verify assertions made by commenters.


We must receive your comments by July 31, 2000.


Send your comments by regular mail or hand deliver them to MSHA, Office of Standards, Regulations, and Variances, 4015 Wilson Boulevard, Room 631, Arlington, VA 22203-1984. You also may send them by telefax (fax) to MSHA, Office of Standards, Regulations, and Variances, 703-235-5551; or by electronic mail (e-mail) to If you send your Start Printed Page 40558comments by fax or e-mail, you must clearly identify them as such. We encourage you to supplement paper comments with computer files on disk; contact us with any questions about format.

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Carol J. Jones, Director; MSHA Office of Standards, Regulations, and Variances; 703-235-1910.

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We have developed extensive records concerning whether to issue regulations limiting the concentration of diesel particulate matter (dpm) in underground coal mines and underground metal and nonmetal mines, and what type of rule would be appropriate for each sector. We have been working on this initiative for a number of years. We issued a proposed rule for underground coal mines on April 9, 1998, and a proposed rule for underground metal and nonmetal mines on October 29, 1998. Following a period for pre-hearing comments on each proposal, we held four public hearings around the country on each proposal. After an extension of the comment period for each proposal, both records closed on July 26, 1999.

We have now determined that it is appropriate to add some documents to each of these records. You are welcome to comment on the additions to both records.

A. Items Being Added to the Metal and Nonmetal Record.

A key feature of the proposed rule for this sector was the establishment of a concentration limit for dpm. Accordingly, in reviewing the record, the agency paid particular attention to assertions by the mining community that the sampling and analytical method which MSHA proposed to use for measuring compliance with that limit would not provide accurate results in many cases. Specifically, we proposed:

Section 57.5061 Compliance determinations.

(a) * * *

(b) The Secretary will collect and analyze samples of diesel particulate matter using the method described in NIOSH Analytical Method 5040 and determining the amount of total carbon * * *

In the preamble to the proposed rule (63 FR 58104 et seq.), in particular a discussion entitled “(3) Methods Available to Measure DPM” (63 FR 58127-58130); in Question and Answer #12 (63 FR 58116-58117); and in the discussion of proposed § 57.5061 (63 FR 58184), we reviewed the various approaches used to determine the concentration of dpm, and explained our rationale for the approach proposed. Moreover, we asserted that the method we proposed to use could accurately determine whether dpm emissions in any underground metal or nonmetal mine exceeded the proposed concentration limit (with an appropriate allowance for a margin of error).

There was extensive comment on this assertion during the four rulemaking hearings and in written pre-hearing and post-hearing comments. While some commenters reaffirmed the validity of various aspects of the method, a number of commenters asserted that we could not rely on this approach for compliance purposes in certain types of mines and under various circumstances.

Specifically, these commenters asserted that some of the material being measured as dpm might well be something other than dpm, an “interferrent.” Some asserted that certain types of mineral dust, in particular graphite and carbonaceous minerals, were interferrents. Other commenters asserted that oil mists from drilling operations and cigarette smoking by miners, which can be present in many underground metal and nonmetal mines, were interferrents. Some commenters supported their claims with study results.

During the hearings, MSHA representatives expressed concerns about the manner in which these studies had been performed and the methodology used. When we examined the information provided for the record about these studies, our concerns were heightened, thus leaving us without enough evidence to verify the existence and scope of the alleged interferences.

We decided that we would attempt to verify the existence and scope of the alleged interferrents while we were reviewing other aspects of the rulemaking record. Other agencies have followed this approach. The situation discussed in Community Nutrition Institute v. Block, 749 F.2d 50 (D.C. Cir. 1984), Circuit Judges Wilkey, Bork, and Scalia, is an example. The case involved studies that Department of Agriculture staff conducted in response to comments alleging deficiencies in a methodology, and completed after the close of the comment period.

Accordingly, MSHA's Pittsburgh Safety and Health Technology Center conducted five investigations to verify these assertions of methodological problems. We have decided to reopen the record to provide the mining community an opportunity to review and comment on this information. Members of the mining community also requested that we reopen the record for this purpose.

B. Items Being Added to the Coal Record

The rule proposed for this sector would have required certain types of underground coal mining equipment to be filtered. We also requested comment on an alternative which would have required certain types of underground equipment to observe an emissions standard. An emissions standard could be achieved using a lower emission engine or filters or both. In either case, the efficiency of available filters is one important consideration in determining the economic and technological feasibility of the rule for coal mines. Thus, during the hearings and in the written comments, there was a great deal of discussion on this topic, and we compiled an extensive record.

Some commenters asserted that paper filters could not achieve a 95% reduction in emissions from current permissible equipment, as we had asserted. Such filters can be directly installed on permissible equipment, without the need for additional equipment to cool the exhaust (so it will not ignite the filter element). While the record does contain considerable evidence on the efficiency of two versions of a system known as the DST® that first cools the exhaust from an engine and then routes it through a paper filter (and in one case a catalytic convertor), it contained no definitive information supporting the assertion of commenters that a paper filter alone could not achieve such efficiencies. Accordingly, in order to verify the assertions of commenters, we contracted with Southwest Research Institute to conduct an investigation toward this end. We are placing the Institute's report of test results in the record and welcome your comments on it.

The record does contain considerable information on the efficiency of hot gas filters (e.g., ceramic monolithic cell, metal sintered, fiber wound, etc.), which will play an important role in reducing emissions from non-permissible equipment under either regulatory scenario described above. This information includes filter efficiency tests conducted by VERT (Verminderung der Emissionen von Realmaschinen in Tunnelbau), a consortium of several European agencies conducting such research in connection with major planned tunneling projects in Austria, Switzerland, and Germany. Since the close of the record, these VERT tests have continued. We believe it is appropriate to consider the full range of their results and are adding their more Start Printed Page 40559recent test data to the record. We welcome your comments on it.

C. Items Being Added to Both Records

Since the record closed, several documents have been published concerning the risk of dpm. This risk information is applicable to both coal's and metal and nonmetal's rulemakings.

The first item is a report by another Federal authority updating information discussed in the record. During the hearings and post-hearing comments, there was considerable discussion of an October 1998 report of the Clean Air Scientific Advisory Committee (CASAC) reviewing an EPA Diesel Health Assessment Document. This committee has issued a new report (“Review of EPA's Health Assessment Document for Diesel Emissions” February 2000) on a revised EPA Diesel Health Assessment Document (EPA, Health Assessment Document for Diesel Emissions, Office of Research and Development, SAB Review Draft, EPA-600/8-90/057D, November 1999). Members of the mining community participated actively in the discussions leading to CASAC's newer report. Accordingly, we believe it would be appropriate to update our record to reflect any new information covered by the revised EPA assessment and the CASAC's review of it. Members of the mining community have requested that we reopen the record for this purpose.

The second item is a study by Saverin, R. et al., “Diesel Exhaust and Lung Cancer Mortality in Potash Mining,” American Journal of Industrial Medicine, 36:415-422 (1999). The unpublished version of the study was discussed at one of the hearings, and we already have the unpublished version of this study in the record. The published version which differs slightly from the earlier translation is now available and it is normal practice to refer to the published version of a study when that version is available. Accordingly, we are adding the published version to the record and welcome your comments on it.

The third item is an epidemiological study investigating the association of lung cancer with occupational exposures to diesel emissions in Germany. Bruske-Hohlfeld, I. et al., “Lung Cancer Risk in Male Workers Occupationally Exposed to Diesel Motor Emissions in Germany,” American Journal of Industrial Medicine, 36:405-414 (1999). The record of this rulemaking includes a lengthy and comprehensive list of relevant epidemiological studies. These were discussed in great detail by the mining community during the hearings and comment period. As a result, we believe it would be inappropriate to leave this recent epidemiological study out of the record. Accordingly, we are adding this study to the record and welcome your comments on it.

The fourth item is a study concerning human response to acute dpm exposures. Salvi, Sundeep, et al., “Acute Inflammatory Responses in the Airways and Peripheral Blood After Short-Term Exposure to Diesel Exhaust in Health Human Volunteers,” Am. J. Respir. Care Med. 159:702-709 (1999). Again, the record of this rulemaking includes a comprehensive list of relevant studies in this regard, and they were discussed by the mining community during the hearings and comment period. Since the Agency is opening the record, the addition of this recent study is appropriate. Accordingly, this study is being added to the record at this time.

Finally, in its review of the record, the agency noted certain comments suggesting that these commenters might not have been aware of certain studies that were part of the general scientific literature covered by reviews which are included and discussed in the record. Accordingly, the agency is placing copies of two such studies directly into the record under their own docket numbers, and will accept any comments on these studies. [Hou, S.M. et al., “Relationship between hprt mutant frequency, aromatic DNA adducts and genotypes for GSTM1 and NAT2 in bus maintenance workers,” Carcinogenesis, 16:1913-1917 (1995); and Ichinose, et al., “Lung Carcinogenesis and Formation of 8-hydroxy-deoxyguanosine in Mice by Diesel Exhaust Particles,” Carcinogenesis, 18:185-192 (1997).]

The agency wants to reassure the mining community that since the agency's risk assessment covers information relevant to both underground coal mines and underground metal and nonmetal mines, any comments on the risk assessment filed in one record have also been placed in the other. In some cases, commenters placed the comments in both records just to be sure MSHA would consider them, but not all did so. The agency will follow this same policy with respect to any comments on the risk studies which are the subject of this notice.

D. Time for Response

The Agency is opening the rulemaking record for additional comment on only the specific items described above. The agency has determined that in light of the limited scope of this reopening, and the extensive familiarity of the mining community with the existing record on the topics involved, the record will remain open for comments on these items for 30 days. The agency does not foresee any extensions will be needed. Accordingly, to facilitate comment by the mining community, the agency will be pleased to telefax or express mail copies of any of the items involved upon request.

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Dated: June 27, 2000.

Robert A. Elam,

Deputy Assistant Secretary for Mine Safety and Health.

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[FR Doc. 00-16561 Filed 6-28-00; 8:45 am]