The American Conference of Governmental Industrial Hygienists (ACGIH) has announced its Notice of Intended Changes (NIC) for Threshold Limit Values (TLV) and Short-Term Exposure Limits (STEL) for 2023. Each year, proposed actions of the TLV and Biological Exposure Indices (BEI) Committees are issued in the form of a Notice of Intended Changes (NIC).
If 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the Committee may change its recommendation to the ACGIH Board of Directors for the matter to be either retained on or withdrawn from the NIC.
Although the United States uses OSHA’s Permissible Exposure Limits (PEL), the rest of the world, including Canada, uses TLVs. NICs do not mean TLVs will definitely change. ACGIH can either adopt them, remove them or keep them listed as NIC for the following year.
A few of 2023 important NICs include:
| CHEMICAL | CURRENT EXPOSURE LIMIT | NOTICE OF INTENDED CHANGE |
| BENZENE | Current TLV – 0.5PPM | NIC TLV – 0.02PPM |
| Current STEL – 2.5PPM | NIC STEL – 0.1PPM | |
| ETHYLENE GLYCOL DIMETHYL ETHER | Current TLV – none | NIC TLV – 0.5PPM |
| FORMIC ACID | Current STEL – 10PPM | NIC STEL – none |
| MEK | Current TLV – 200PPM | NIC TLV – 75 PPM |
| Current STEL – 300PPM | NIC STEL – 150 PPM | |
| NITRIC ACID | Current STEL – 4 PPM | NIC STEL – 0.025 PPM as inhalable fraction and vapor (IFV) |