How to identify and classify hazards?
A hazard is an intrinsic property of a chemical substance or mixture that makes it capable of causing harm to human health or the environment.
It is important to distinguish between a hazard and a risk:
Hazard
The inherent property of a substance (e.g., flammable, toxic, corrosive).
Risk
The likelihood that harm will occur under specific conditions of use or exposure.
Why does hazard identification matter?
Identifying hazards is the first step in ensuring the safe management of chemicals.
It is essential in order to:
Users of chemicals must be informed about the hazardous properties of chemicals in order to ensure safe handling and prevent damage to workers, consumers and the environment. This requires all supply chain actors to understand and forward this information to their customers.
To avoid misunderstandings in international trade, a globally harmonised system (GHS) for classification and labelling is used. In the EU, this system is implemented with some variations such as additional hazard statements, through the European Regulation on the Classification, Labelling and Packaging of Substances Mixtures and specific articles – CLP Regulation (EC) No 1272/2008.
What are the hazardous properties of chemicals?
The classification is based on data about the effects of a substance on organisms or the physical-chemical conditions (e.g. explsion), which may be obtained from testing or other sources. CLP Regulation‘s pictograms and hazard classes:
Explosives
Explosives
Self-reactive substances and mixtures
Organic peroxides
Flammable
Flammable gases
Aerosols
Organic peroxide
Pyrophoric liquids
Self-heating substances and mixtures
Substances and mixtures which in contact with water emit flammable gases
Oxidising
Oxidising gases
Oxidising liquids
Oxidising solids
Gases under pressure
Acute toxicity
Corrosion
Skin corrosion / irritation
Serious eye damage/eye irritation
Substances and mixtures corrosive to metals
Health Hazard
Respiratory or skin sensitisation
Germ cell mutagenicity
Carcinogenicity
Aspiration hazard
Reproductive toxicity
Specific target organ toxicity (single/ repeated exposure)
Hazardous Effects
Acute toxicity
Skin corrosion / irritation
Serious eye damage/eye irritation
Respiratory or skin sensitisation
Specific target organ toxicity (single/ repeated exposure)
Hazardous to the ozone layer
Hazardous to the aquatic environment
How do we classify substances and mixtures?
Substance and substances in mixture identification
Correct identification is essential. This includes:
- IUPAC name (sometimes the standard name, trade name, abbreviation, etc.)
- CAS number
- EC number
- Composition and concentration (for mixtures)
Information can be verified using:
- ECHA CHEM database
- Safety Data Sheets (SDS),
- supplier documentation.
Incorrect identification may lead to incorrect classification.
Assessment of Available Information
All relevant data must be collected and evaluated, including:
- test data,
- published scientific literature,
- harmonised classifications (if available),
- read-across from similar substances,
- for mixtures — classification of individual components.
The information must:
- be reliable and scientifically valid;
- relate to the physical form in which the substance or mixture is placed on the market or reasonably expected to be used;
- comply with Articles 5 and 9 of the CLP Regulation.
In the event that there is insufficient expertise to evaluate the data, a qualified expert should be consulted.Further guidance is available in the ECHA Guidance on the Application of the CLP Criteria.
Determination of Classification
Based on the evaluated data:
- Substances are classified according to CLP hazard criteria.
- Mixtures are classified using:
- performed test data on the mixture itself, or
- calculation methods based on the classification and concentration of their components.
Importers must ensure that classifications comply with EU requirements and should not automatically rely on non-EU classifications without verification.
What obligations are there related to labelling?
Labelling according to CLP regulation is the outcome of classification for chemicals.
Hazardous chemicals must be clearly labelled before being placed on the EU market.
This means the relevant pictograms must be on the label, the Hazard (H) statements that provide information on the particular adverse effect the chemical may cause as well as the Precautionary (P) statements that inform about the protection measures to take when handling the chemicals. In particular the H statements are crucial for chemicals risk magement, as they:
In regard to substance labelling, information is available in the ECHA CHEM database.
In regard to mixtures, labelling depends on mixture classification according to the CLP regulation Annex I and II.
More resources
The Classification and Labelling Table provides a clear, structured, and easy to use overview of chemical hazard classification and labelling requirements. It allows users to quickly identify hazard classes and categories, corresponding pictograms, signal words, hazard statements (H codes), and additional EU hazard statements in one comprehensive format.
Guidance documents to facilitate the implementation of CLP by describing good practice on how to fulfil the obligations.
This document describes specific provisions for the labelling and packaging of chemical substances and mixtures under Titles III and IV of the Regulation (EC) No 1272/20081 (the CLP Regulation or “CLP”). The aim of this document is to assist manufacturers, importers, downstream users and distributors of substances and mixtures in the effective application of the CLP Regulation.
The ECHA mixture classification process is the systematic assessment of a chemical mixture’s hazards based on its components or test data to determine its classification and ensure proper labelling and communication of risks under the EU CLP Regulation.