U.S. Department of Labor

Mine Safety and Health Administration 4015 Wilson Boulevard Arlington, Virginia 22203-1984

FROM:           EARNEST C. TEASTER, JR.
                       Administrator
                            Metal and Nonmetal Mine Safety and Health

SUBJECT:      Sampling for Contaminants

Scope
This procedure instruction letter applies to Metal and Nonmetal Mine Safety and Health (MNMSH) enforcement personnel.

Purpose
This letter revises and clarifies MNMSH's industrial hygiene sampling strategy for airborne contaminants.

Procedure Instruction
Maximum effectiveness of health sampling is achieved by sampling occupations, mines, contaminants, and processes where there is the greatest likelihood that overexposures exist. Therefore, MNMSH enforcement personnel will focus their sampling where any of the following criteria apply:

High risk occupations - Attached to this procedure instruction letter is a list of occupations defined as "high risk" for respirable dust at sand, gravel, and stone operations. At least annually, enforcement personnel will sample a representative number of miners from each of the high risk occupations at each operation, unless previous sampling has demonstrated that adequate engineering and administrative controls are in place to ensure compliance and there is no history or little likelihood of overexposure for that occupation at that property. If sampling is not performed, enforcement personnel will document the controls being used and the reason they believe miners are not at risk; and they will write "no samples required" on the Inspection/ Investigation Data Summary, MSHA Form 4000-40. Field office supervisors will review the available information to confirm that sampling is not necessary.

In addition to the occupations listed, enforcement personnel should also sample any other occupations at these operations that they believe are at risk.

For commodities other than sand, gravel, and stone, enforcement personnel will review the mine's history of sampling for contaminants and discuss the operation with the field office supervisor to determine which occupations should be considered high risk and which should be sampled.

Drillers, drill helpers, and abrasive blasters - Although drillers and drill helpers are high risk occupations, they are not included in the occupations to be sampled at least annually because they are primarily regulated through work practice standards. Title 30 CFR 58.620 requires holes to be collared and drilled wet, or other effective engineering dust control measures to be used, when drilling non-water-soluble material. Mine operators must have these engineering controls in place. Also, 30 CFR 58.610 requires that when an abrasive blasting operation is performed, any exposed miner must use, as required by 30 CFR 56/57.5005, respirators approved for abrasive blasting by NIOSH under 42 CFR 84, or the operation must be performed in a totally enclosed device with the miner outside the device. If all of these criteria are not met, a violation exists. Sampling need only be conducted if properly maintained engineering controls appear to be inadequately designed to control the hazard. If an overexposure is found, the evaluation of the situation will be coordinated with District, Headquarters, and Technical Support personnel to determine the underlying cause before issuing any citations.

Mines with a history of overexposure - Mines that have any history of personal sampling overexposure(s) to airborne contaminants will be sampled at least annually for the hazard(s) and occupation(s) of concern. This ensures that problems contributing to the overexposure have been effectively corrected. When overexposures are identified and corrective measures are taken, inspectors will sample to verify compliance. The mine and occupations should also be sampled on the next inspection to ensure that corrective measures taken by the operator are still adequate. Additionally, enforcement personnel will review the effectiveness of the mine's engineering and administrative controls, and respiratory protection program where required, during each regular inspection.

The District will provide each field office supervisor with a list of mines exhibiting a history of overexposure. The field office supervisor will ensure that these mines are appropriately sampled.

Mines processing, producing, or associated with potential exposure to contaminants requiring adherence to proper work practices and maintenance of controls - Once the high risk occupations at these properties have been identified, enforcement personnel will sample a representative number of these occupations at least annually, and review the effectiveness of the mine's engineering and administrative controls and respiratory protection program where required during each regular inspection.

The District provides each field office supervisor with a list of mines known to process these minerals. The field office supervisor then ensures appropriate sampling is conducted.

Mines where the ore or mineral processing procedures use chemicals that may present a hazard if improperly used or released - The work practices and processing procedures should be reviewed during each inspection to ensure that adequate precautions are taken, including the proper use of personal protective equipment when appropriate. Enforcement personnel should also conduct sampling when and where there is a potential for an overexposure.

New mines, mines which have had significant changes in operations or processing, and mines with no sampling history - These mines should be sampled adequately to assess miners' exposures. Once the exposures have been determined, enforcement personnel should revert to sampling in accordance with conditions described previously.

Attachment