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Considerable progress has been made in each study component of the Taconite Workers Health Study


  1. Occupational Exposure Assessment

    Data from the Mine Safety and Health Administration (MSHA) and primary exposure monitoring measurements made in the taconite industry for the time period 1955 to present have been obtained. Review of the MSHA data has been completed.

    Data on historical exposure monitoring measurements from companies has been obtained and the assessment of current exposures at the currently operational mines is continuing.  Based on these measurements the workforce is being divided into similarly exposed groups (SEGs).  Two workers from each SEG are being sampled for fibers and respirable dust and silica.  At the same time, area samples are being obtained for more detailed analysis.  Area samples include real-time monitoring for particle number, surface area and mass concentrations.  On-site testing is expected to be completed by February 2011.

    A detailed study of the efficacy of existing exposure control measures including engineering controls, work practices and administrative controls, and personal protective equipment is also being conducted.

  2. Mortality (cause of death) Study and Cancer Incidence Study

    Historical work history records from the cohort of taconite workers are being reviewed to map the detailed work histories into similarly exposed groups (SEGs) to be able to use the information obtained from the Occupation Exposure Assessment.

    The cohort of taconite workers has been matched with mortality records and the Minnesota Cancer Surveillance System (MCSS) to identify deaths and cases of cancer among the group.  Acquisition of death certificates and cause of death information will be completed by January 2011.

    From over 48,000 individuals it has been determined that 31,385 are alive, 13,786 are deceased, 506 are presumed deceased, and 525 are of an unknown status, as of the end of 2008.

  3. Respiratory Health Survey of Taconite Workers and Spouses

    Testing at the Virginia Regional Medical Center in Virginia, MN was completed in August and testing at the Bay Area Medical Center in Silver Bay, MN was completed in October.  Over 1800 individuals participated (approximately 1300 workers and 500 spouses) in the screening which included a limited physical exam, a chest X-ray, a blood draw, breathing tests and completing a questionnaire.  Analysis of the data is underway and will incorporate the exposure information obtained in the Occupational Exposure Assessment to further understand the lung tests results.

    The process of having the X-ray read by NIOSH certified B-readers according to the International Labor Organization (ILO) standards is well under way and expected to completed in February 2011.

  4. Environmental Study of Airborne Particulates
    Community air sampling at seven sites in northeastern Minnesota (Silver Bay, Virginia, Hibbing, Keewatin, Babbitt, Duluth and Eli) has been completed by Natural Resources Research Institute (NRRI).  In-plant air sampling has been completed by NRRI at four taconite plants.  At each plant four locations were sampled, (crusher, magnetic separator, agglomerator/ball drums and kiln pellet discharge area).  Lake sediment core samples at two sites have been collected and they are currently being processed.