Each year, the American Conference of Governmental Industrial Hygienists (ACGIH) reviews and proposes updates to its Threshold Limit Values (TLVs) through the Notice of Intended Changes (NIC). While the 2026 NIC represents the most recent public release, many proposed changes continue the long-term trend toward more protective occupational exposure limits.
As exposure limits decrease, monitoring programs must be capable of detecting increasingly lower concentrations of workplace contaminants. In many cases, proposed reductions suggest that workers may require greater protection from certain chemical exposures.
Selected 2026 NIC Proposed Exposure Limits
| 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 and Exposure Monitoring
When TLVs decrease, exposure levels previously considered acceptable may warrant additional evaluation and control measures. Lower occupational exposure limits can increase the need for proactive industrial hygiene programs designed to identify and manage potential risks before they become compliance or health concerns.
If lower limits are ultimately adopted, organizations may need to reassess engineering controls, exposure monitoring strategies, and respiratory protection programs to ensure adequate worker protection.
Reduced exposure limits also place greater demands on monitoring programs, often requiring:
- More frequent exposure assessments
- Lower analytical detection limits
- More sensitive sampling and laboratory methodologies
- Defensible, high-quality data capable of demonstrating compliance with increasingly protective limits
Taking a proactive approach now can help organizations prepare for future regulatory and industry changes while avoiding surprises if new TLVs are finalized.
How SGS Supports Evolving TLVs
As occupational exposure limits continue to trend downward, reliable and defensible sampling data become increasingly important. SGS provides comprehensive industrial hygiene and environmental services designed to help organizations prepare for more protective TLVs and enhanced monitoring requirements.
Our capabilities include:
- Low-level analytical testing with sensitive detection limits
- Complimentary sampling media
- Free air sampling pump program
- Occupational exposure monitoring
- Indoor environmental quality assessments
Why SGS
At SGS, we help organizations adapt to evolving occupational exposure guidelines and strengthen worker protection programs.
Our industrial hygiene specialists can assist with developing effective sampling strategies, selecting appropriate analytical methods, determining optimal sampling durations, and establishing suitable sample volumes to support accurate exposure assessments.
Whether you’re evaluating current workplace conditions or preparing for potential future TLV changes, SGS can provide the expertise and analytical support needed to make informed decisions.
Contact us today to learn how SGS can support your industrial hygiene and exposure monitoring programs