Ten-digit CAS registry numbers will begin appearing in mid-January. The move comes in response to high volumes of substance registries. The 10th digit will appear on the far left of the CAS registry numbers, as shown below:
The addition will not affect CAS's SciFinder and STN, or Allured's Flavor and Fragrance Materials database. For more information, contact CAS; tel: 1-614-447-3700.