What it identifies

CAS assigns a unique identifier to a specific substance. It helps resolve confusion between common, systematic or differently translated names. Different forms of a substance may have different identifiers. A product’s trade name does not necessarily correspond to a single substance: it may describe a mixture of several components.

Use in a product inventory

Linking components in a safety data sheet to CAS numbers helps review duplicates and find toxicological information. Name, stated concentration, supplier and sheet version are also retained. Recording only the code loses information needed to understand the product actually used.

What the code cannot establish

The number does not directly describe toxicity, flammability, purity or protective measures. Nor does it establish that a use is authorised or that a product meets every requirement. These decisions require relevant sources and working conditions. Two products sharing a CAS component may have different mixtures and risks.

Handling discrepancies

If name and code do not appear to match, they are checked against a reliable source and with the supplier before the inventory is consolidated. Copying a search result without checking chemical form or composition can propagate an error. For legal obligations, identification must be interpreted under the applicable text rather than resolved solely by numerical matching.

Inventory clean-up example

In a hypothetical example, two departments register the same solvent under different names. CAS helps identify the match and group information about that component. Commercial products nevertheless remain separate if concentration, additives or use conditions differ; unifying names does not make them interchangeable without assessment.

A useful reference with context

CAS should link documents rather than serve as the only decision field. Searches for exposure limits, incompatibilities or substitutes must retain source traceability. Where an identifier is missing or a mixture has complex composition, the limitation is documented and sufficient information requested rather than inventing a code to complete the table.