GHS — the Globally Harmonized System of Classification and Labelling of Chemicals — is no longer a reference. Law on Chemicals No. 69/2025/QH15 cites it directly in Article 23.
Organisations and individuals producing or importing chemicals must classify and label them before the chemicals are put into use or circulated on the market, and are legally responsible for the classification result and the information on the label (clause 1 of Article 23).
If a hazardous property not reflected in the classification information is discovered, organisations and individuals in chemical activities must promptly notify the producer or importer so that the chemical is classified and labelled again (clause 5 of Article 23).
The GHS classification determines which hazard class and division a chemical belongs to — and therefore where in the warehouse it may be placed and what it may be placed next to. It is, with the safety data sheet, the first thing a warehouse operator needs.