Manganese Exposures

Discussion in 'United States Navy' started by Jerrel, Feb 9, 2008.

  1. Jerrel

    Jerrel New Member

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    Manganese Exposures for Navy Workers.

    This information was taken from a study conducted by the Navy Environmental
    Health Center. It suggests that Navy personnel may be at risk for exposure
    to manganese. Conclusions presented in this study should be considered by
    DA Health authorities to determine if similar exposure potentials exist for
    Army personnel.

    In June 1996, the Deputy Under Secretary of Defense (Environmental
    Security) requested an evaluation of manganese exposures to Navy workers,
    and an assessment of the impact of a reduced manganese standard.

    Background note - The American Conference of Governmental Industrial
    Hygienists (ACGIH) Chemical Substances TLVr Committee has determined that
    manganese is a chronic toxin and that a time weighted average (TWA)
    exposure limit over the work day is appropriate. In 1992, the TLV Committee
    proposed a Notice of Intended Change for manganese as a TLV-TWA of 200
    ug/m3 as manganese for elemental and inorganic compounds. The previous TLVs
    were similar to the OSHA PELs, which were vacated by the Eleventh Circuit
    Court of Appeals in July 1992. These values were 5,000 ug/m3 as a ceiling
    limit for dust, 3,000 ug/m3 as a short-term exposure limit (STEL), with a
    1,000 ug/m3 limit as an 8hour TWA for fumes. In setting the PELs OSHA had
    concluded that both a TWA and a STEL limit were required to protect workers
    from manganese fume poisoning, lung damage and pneumonia. Because the PELs
    were vacated, the current OSHA PEL reinstates the old value of 5,000 ug/m3
    as a ceiling limit for both dust and fume. Manganese may be absorbed both
    from the lungs and GI tract. Inhalation exposure to high levels of
    manganese can lead to a disabling neurological syndrome "manganism".

    The Chief of Naval Operations (N45 staff) convened a Navy working group
    comprised of technical professionals representing the Bureau of Medicine
    and Surgery, Marine Corps, Naval Sea Systems Command, Naval Air Systems
    Command, Navy Environmental Health Center, and Naval Surface Warfare Center
    Carderock Division. This group analyzed the tasking and developed an action
    plan to prepare this report. The primary author and coordinator for the
    report was Mr. John Bishop, Navy Environmental Health Center. The study
    concluded the following:

    *666 exposures were reviewed
    *95 % of the TWA exposures (with 95 %
    confidence) of the population performing the
    operation were below the anticipated OSHA
    PEL of 200 ug/m3
    *7% of the exposures were at or above the
    anticipated action level of 100 ug/m3, and
    *3.5% of the exposures were at or above the
    anticipated PEL of 200 ug/m3.
    *Work operations with assessments greater
    than 100 ug/m3 are mechanical metal cleaning
    (e.g., abrasive blasting), welding, thermal
    cutting, and utilities (e.g., boiler
    maintenance).
    *There were two mechanical cleaning
    assessments that resulted in concentrations
    >1000 ug/m3.

    The report also summarized types of engineering control that is being used
    to reduce manganese exposures to workers.

    SOURCE: http://list. uvm.edu/cgi- bin/wa?A2= ind9704D. ..FETY&P=4758

    Jerrel svr
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