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Manganese Exposures for Navy Workers |
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US NAVY BT's, Boilermakers, Boilerman, Boiler
tech's
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. |
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