Hazard classification is the engine at the heart of product compliance. Labeling, safety data sheets, transport classification, storage rules, and notification obligations all stem from this. If the classification is wrong, everything dependent on it is wrong.
The business side of GHS
GHS (Global Health Safety Board) is a system developed by the United Nations that ensures the classification and communication of chemical hazards worldwide using the same criteria and language. It is reviewed every two years; the most current version is the 11th revised edition, published on September 12, 2025. This revision clarified the classification criteria for aerosols and chemicals under pressure, added guidance for animal-free methods in skin sensitization, introduced a new classification for hazards through contribution to global warming, and simplified precautionary statements.
An important distinction: GHS is a framework , not directly implemented legislation. Each country transposes GHS into its own legislation, and this transposition occurs in each country from different versions, at different times, and with different options. The result is that the same product can be classified differently in different markets. It is therefore essential that the harmonization system maintains separate classification results for each country.
Physical injuries
Explosives, flammable gases and liquids, aerosols, gases under pressure, oxidizers, self-reacting agents, organic peroxides, corrosives for metals, and others.
Health risks
Acute toxicity, skin and eye effects, sensitization, mutagenicity, carcinogenicity, reproductive toxicity, target organ toxicity, and aspiration harm.
Environmental damage
Harmful effects include damage to the aquatic environment (acute and chronic), damage to the ozone layer, and, according to the latest revision, contribution to global warming.
Classification of mixtures: a computational approach
There are three ways to classify mixtures: using the mixture's own test data, derivation from data of similar mixtures using bridging principles, and calculation from data of the components . In practice, the vast majority of mixtures are classified computationally because it is neither possible in terms of time nor cost to produce a complete test set for every formulation variant.
The value of classification from prescription on the compliance side.
The ability to calculate a product's hazard profile solely from its formula, before the product is physically produced, provides three distinct advantages for compliance management:
Preliminary testing: During the formulation design phase, it is determined whether the product will cause problems in the target market. This avoids the surprise of "we cannot sell this product in that market" after product development.
Aggregate reassessment: When an item is reclassified or a rule changes, the entire portfolio is recalculated, and documentation is updated only for products whose results have changed.
Justification record: This document details the classification method, data, and threshold used. During audits, the question "why this classification?" is answered with a step-by-step explanation of the calculation process.
The limitations of the calculation should also be clearly indicated: most physical hazards require self-measurement of the mixture. The system should report separately which class has been calculated, which is awaiting measurement, and which data is missing.