ACGIH Board Ratifies 2021 TLVs and BEIs


Cincinnati, Ohio — January 7, 2021 — ACGIH announced that its Board of Directors ratified the 2021 Threshold Limit Values (TLVs) for Chemical Substances and Physical Agents and Biological Exposure Indices (BEIs). The Board also approved recommendations for additions to the Notice of Intended Changes (NIC).

Click here for the listing of the substances that were acted upon. The Annual Reports of the ratifications of the ACGIH Board can be found online at ACGIH members can download the electronic version of the Annual Reports at no cost. Nonmembers may also acquire the Reports through the ACGIH website for $24.95.

Draft Documentation for the substances on the Notice of Intended Changes (NIC) are currently available for purchase at Documentation for the adopted substances and agents are also available for purchase. All Documentation are in PDF format and priced at $60 each. ACGIH members are entitled to (10) Complimentary Documentation downloads per year.

The 2021 TLVs® and BEIs® book is now available in digital format. The print version will be available soon. Both print and digital versions of the 2021 Guide to Occupational Exposure Values will be available soon. Those interested in ordering the 2021 TLVs and BEIs book and the 2021 Guide to Occupational Exposure Values can do so online at, by phone at 513-742-2020, or by fax at 513-742-3355. Please visit the ACGIH website at for updates on availability.

TLVs and BEIs are guidelines to be used by professionals trained in the practice of industrial hygiene. The TLVs and BEIs are not designed to be used as standards. The TLVs and BEIs are health-based values established by committees that review existing published and peer-reviewed literature in various scientific disciplines. Based on the available information, ACGIH formulates a conclusion on what level of exposure the typical worker can experience without adverse health effects. There is no consideration given to economic or technical feasibility.

The Notice of Intended Changes (NIC) is comprised of those substances and physical agents for which a TLV/BEI is proposed for the first time, for which a change in the Adopted value/index is proposed, for which retention as an NIC is proposed, or for which withdrawal of the Documentation and adopted TLV/BEI is proposed. In each case, the proposals should be considered trial values during the period they are on the NIC. These proposals were ratified by the ACGIH Board of Directors and will remain on the NIC for approximately one year following this ratification. If during the year, the Committee neither finds nor receives any substantive data that change its scientific opinion regarding an NIC TLV/BEI, the Committee may then approve its recommendation to the ACGIH Board of Directors for adoption.  If the Committee finds or receives substantive data that change its scientific opinion regarding an NIC TLV/BEI, the Committee may change its recommendation to the ACGIH Board of Directors for the matter to be either retained on or withdrawn from the NIC.

Documentation is available for each of the substances on the NIC and their proposed values.

This notice provides not only an opportunity for comment on these proposals, but it also solicits suggestions for substances to be considered for TLVs and/or BEIs, such as those found on the current Under Study List. Comments or suggestions should be accompanied by substantiating evidence in the form of peer-reviewed literature and forwarded in electronic format to the  ACGIH Science Group ( Please refer to the ACGIH TLV/BEI Development Process on the ACGIH website ( for a detailed discussion covering this procedure and methods for input to ACGIH.

ACGIH recommends that all TLV and BEI users read the Statement of Position Regarding the TLVs and BEIs, which outlines the proper usage of TLVs and BEIs. The Statement of Position can be found in the TLV/BEI Guidelines section of the ACGIH website ( In addition to the Statement of Position, visitors to this site will find other useful information on TLVs and BEIs, including the following:


ACGIH is a 501(c)(3) charitable scientific organization that advances occupational and environmental health. ACGIH is one of the industry’s leading publications resources, with approximately 400 titles relative to occupational and environmental health and safety, including the renowned TLVs and BEIs. For more information, visit the ACGIH website at or call our Customer Service Representatives at 513-742-2020.