Anyone working in chemical new materials, laboratory R&D, import/export trade, or EHS management will encounter three key terms on a daily basis: MSDS, SDS, and CAS NO. They appear in material receiving, factory safety inspections, product shipping, customer audits, customs declaration, and laboratory registration. Yet even after years on the job, many professionals remain unclear about how they differ.
Quick Core Takeaway
To build a clear picture from the start, remember these basic definitions:
1. CAS NO (CAS Registry Number) = the chemical’s unique “identity card”
It is permanently assigned to each pure chemical substance, globally recognised and unchanged over time. It elegantly resolves the industry‑wide confusion caused by different names for the same substance and the same name for different substances.
2. SDS = the current GHS‑compliant “Safety Data Sheet”
This is the internationally harmonised and domestically mandated chemical safety document under current regulations. It follows a standardised 16‑section format and serves as the primary document for chemical safety management, trade circulation, and safety evaluation filings.
3. MSDS = the older, superseded safety data sheet (predecessor to SDS)
It lacked a unified format and varied widely in content quality. It is now considered an outdated standard and is generally not accepted in formal compliance contexts.
An Easy Analogy for a Clear Understanding
CAS number = the chemical’s unique ID number (its permanent identifier)
SDS/MSDS = the chemical’s safety dossier (health report and instruction manual)
Post time: Jun-29-2026
