Revised TLV for Manganese

Revised TLV for Manganese

The American Conference of Governmental Industrial Hygienists (ACGIH) advised in February 2013 that it had adopted the proposed change to the Threshold Limit Value (TLV) for manganese. The change was published in the 2013 Edition of its TLVs and Biological Exposure Indices (BEIs) publication. The new TLV of 0.02 mg/m3 for respirable particulate matter represents a ten-fold reduction from the previous 0.2 mg/m3 TLV. The new TLV for manganese includes a 0.1 mg/m3 limit for inhalable manganese particulate.

The ACGIH’s change in the manganese particulate TLVs appears to be based on reports of pre-clinical neurobehavioral and neuropsychological changes in workers exposed to chronic low levels of manganese. 

The ACGIH acknowledges that its TLVs are not consensus standards and do not take into account economic or technical feasibility issues. The ACGIH recognizes that some governmental entities may utilize its TLVs in adopting standards.

Where exposures are assessed to be over the TLV, many approaches can be considered in the workplace for reducing manganese exposure levels to below the new TLV.

ACGIH Manganese TLV Change Statement

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