Manganese Exposures For Navy Workers.

[allan]

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

Edited December 23, 2007 by allan