NIOSH to Reevaluate Recommended Exposure Limit for Inorganic Lead

Published August 22, 2018

A new request for information issued on Aug. 21 by NIOSH announces the agency’s intention to establish an updated recommended exposure limit for inorganic lead. The current REL for inorganic lead is 50 μg/m3 as a time-weighted average concentration for an 8-hour work shift during a 40-hour workweek. NIOSH also intends to develop updated recommendations on the potential health risks, medical surveillance, and recommended measures for the safe handling of inorganic lead. The RFI is part of NIOSH’s effort to identify RELs that may not be adequate to protect workers from adverse health effects due to exposure.

Occupational exposures to inorganic lead, a naturally occurring soft gray metal, are found in many industries, including construction, electronic waste recycling, and smelting and refining. Workers can be exposed through inhalation, ingestion, and through the skin.

NIOSH seeks both published and unpublished materials, including reports and research findings, to help the agency evaluate the possible health risks of occupational exposure to inorganic lead. This includes information such as work tasks and scenarios with a potential for exposure to inorganic lead, trends in the production and use of inorganic lead, and control measures for minimizing worker exposure to inorganic lead. NIOSH also requests data pertaining to the feasibility of establishing a more protective REL for inorganic lead. A full description of the information NIOSH hopes to gather can be found in the Federal Register notice.

The RFI is open for approximately two months. Comments are due by Oct. 22, 2018. Electronic comments can be submitted via the docket on, the federal e-rulemaking portal.

OSHA’s permissible exposure limit for inorganic lead is 50 μg/m3 for an 8-hour period with an action level of 30 μg/m3. ACGIH’s threshold limit value for lead and inorganic compounds is 50 μg/m3 as a time-weighted average. The TLV carries an A3 carcinogenicity classification, ACGIH’s classification for agents that are confirmed animal carcinogens with unknown relevance to humans.