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TLV®/BEI® Resources

Under Study List

Each Committee solicits information, especially data, which may assist in its deliberations regarding the substances, agents, and issues listed. Comments and suggestions, accompanied by substantiating evidence in the form of peer-reviewed literature, should be forwarded in electronic format, to The ACGIH® Science Group at In addition, ACGIH® solicits recommendations for additional substances, agents, and issues of concern to the industrial hygiene and occupational health communities. Please refer to the "ACGIH® TLV®/BEI® Development Process" for a detailed discussion covering this procedure and methods for input to ACGIH®.

The Under Study List is published each year by February 1 on the ACGIH® website (, in the Annual Reports of the Committees on TLVs® and BEIs®, and later in the annual TLVs® and BEIs® book. In addition, the Under Study list is updated by July 31 into a two-tier list.

  • Tier 1 entries indicate which chemical substances and physical agents may move forward as an NIC or NIE in the upcoming year, based on their status in the development process.

  • Tier 2 consists of those chemical substances and physical agents that will not move forward, but will either remain on or be removed from the Under Study list for the next year.
This updated list will remain in two-tiers for the balance of the year. ACGIH® will continue this practice of updating the Under Study list by February 1 and establishing the two-tier list by July 31 each year.

Chemical Substances and Other Issues Under Study (TLV®-CS)

Chemical Substances and Other Issues Under Study (BEI®)

Physical Agents Under Study (TLV®-PA)

Biologically Derived Agents Under Study

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