View Categories

How to identify and classify hazards?

Table of Contents

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:

  • Assess potential risks to people and the environment.

  • Determine applicable regulatory requirements;

  • Ensure safe handling and usage in workplaces and industrial processes;

  • Enable informed decision-making when selecting chemicals for products or production processes;

  • Ensure correct labelling and communication throughout the supply chain.

All actors involved in the supply chain – manufacturers, importers, distributors and downstream users – must be informed about the hazardous properties of chemicals in order to ensure proper communication about safe usage when placing such chemicals on the market.

To avoid misunderstandings in international trade, a globally harmonised system (GHS) for classification and labelling is used. In the EU, this system is implemented 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 the proven, presumed and suspected hazardous properties of a substance or mixture, and not on the likelihood of exposure and risk considerations. CLP Regulation 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.

Helpful resources may include:

Further guidance: https://echa.europa.eu/support/mixture-classification/

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.

The label ensures that:

  • Workers and consumers are properly informed about hazards,

  • Instruction regarding safe usage is appropriately managed

  • Information is communicated consistently across the EU,

  • Supply chain actors comply with legal requirements.

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. 

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.