2026 ACGIH Notice of Intended Change (NIC) Chemicals
Every year, the American Conference of Governmental Industrial Hygienists (ACGIH) reviews its Threshold Limit Values (TLV) and publish proposed NICs for chemicals. These are the maximum concentrations of hazardous materials to which workers can be exposed without experiencing significant health effects.
While NICs are not final limits, they give industrial hygienists an early look at potential changes before they are formally adopted in a future TLV publication. In many cases, these proposals reflect emerging evidence that suggests workers may need greater protection from certain exposures.
The 2026 NIC list includes both revised limits for existing chemicals and new proposed TLVs for substances that previously had none.
Listed below are the new proposed values that may be adopted next year, and may include some new chemicals as well as existing chemicals:
| Chemical | Current TLV | 2026 NIC |
| Aniline | 2ppm | 0.1ppm |
| Carbon Monoxide | 25ppm | 20ppm |
| 1,4 dichloro 2 butene | 0.02ppm | 0.01ppm |
| Ethyl Butyl Ketone | 50ppm | 10ppm |
| o-Toluidine | 0.5ppm | 0.1ppm |
| Nitric Acid | 2ppm | 2ppm |
| Dicamba | 10mg/m3 | 10mg/m3 |
| DEET | none | 10mg/m3 |
| Propargyl Alcohol | 2ppm | 1ppm |
| Dimethyl Carbamoyl Chloride | none | 0.005ppm |
Impacts on Worker Safety
A lower TLV implies that exposure levels once considered safe may now be a hazard, stressing the need for proactive safety measures.
Since a lot of these NICs are lower, the need for proactive safety measures to protect workers is required. If new low levels of exposure are adopted, workers may require respiratory protection and/or air quality monitoring.
To maintain safety, prevent injuries, and promote healthier environments for all workers, it is important to remain informed and make sure that your exposure control strategies and workplace assessments are current with the latest TLV levels. Taking a proactive approach now can help organizations prepare for potential future changes and avoid surprises if new TLVs are finalized.
Why SGS
When exposure limits change, or are likely to change, having reliable sampling data becomes even more important. At SGS, we’re committed to helping you meet the new lower exposure limits and ensuring that your workplace complies with the latest TLVs.
For accurate and efficient chemical exposure monitoring, we provide complimentary sampling media, a free air sampling pump program, and an experienced team that will assist you in creating a sampling plan that includes choosing the right analytical methods, determining how long to collect air samples, and the required volume.
Contact us today to learn more about how we can support your industrial hygiene needs.