• Dale Allen

GHS Safety Data Sheets Explained: Section 3

Updated: May 4

Section 3: Composition and Information on Ingredients

In Section 3, the supplier will provide information on whether the product is a substance or a mixture. They will also identify the ingredients and impurities which contribute to the hazards of the product.

Is the Product a Substance or a Mixture?

While this guide will list two subsection under Section 3, only one subsection will appear on a safety data sheet. If the product is a chemical element (e.g. phosphorus) or a compound of a chemical element (e.g. phosphorus trifluoride), then it is known as a substance. However, most substances have some impurities and will not be a 100% pure substance.

Those impurities contribute to the hazards inherent in the product considerably, even if they are very small.

Product of industrial processes may also be considered substances (e.g. 4-60 petroleum ether is a concoction of different hydrocarbons, but is considered a single substance). Other substances will contain additives which are required to stabilise them, and they are still considered a substance.

If the product is a formulated mixture of substances, then it is known as a mixture (e.g. paints).

3.1. Substance

In subsection 3.1 the supplier identify the ingredient of the product alongside the additives or impurities which contribute to the classification of the substance and are hazardous.

Each ingredient of the product will be identified by:

Chemical Name

Systematic names are complicated and as such are often abbreviated or substituted by a common name. Where the substance is listed in Part 4 of CLP, then the proper chemical name which appears in the regulations will be used.

Identification Number

As previously mentioned earlier in this guide, the identification number is a very important identifier. This is especially true if the chemical is structurally complex. For substances, at least one identification number should be present in this substance. This is a legal requirement.

If you find that the chemical name is unclear or has been abbreviated, then the identification number will allow you to quickly and easily confirm the identity of the chemicals.

3.2. Mixture

In subsection 3.2 the supplier will provide a list of the hazardous substances which make up the mixture. It is unlikely you will find a full list of the compositional details of the mixture, but some suppliers may provide a full description.

If the mixture - and none of its ingredients - are classified as hazardous substances, then the supplier in not required to provide the ingredients.

The ingredients and impurities which makes up the mixture and are classified as hazardous to human health or the health of the environmental will be listed in this subsection. However, this is only required if those ingredients or impurities are recorded as being above certain concentration levels.

Those concentration levels are dependent on the hazard presented by the mixture or its ingredients. The threshold get lower as the level of risk rises.

As previously mentioned in this, there are some substances which must be included in this subsection. Persistent Bioaccumulative and Toxic or very Persistent, very Bioaccumulative (vPvB) substances and substances which were assigned community exposure limits (IOLEVs or ILVs) must both be included if they are present in concentrations above 0.1%.

Each ingredient of the mixture will be identified by:

Chemical Name and Identification Number

The information required for mixtures is the same as that of substances. This subsection should list the actual names of the individual substances in the mixture and not their trade names.

REACH Registration Number

Any ingredient registered under REACH will have been assigned a REACH registration number. This number should be included in this subsection. Distributors may omit the last four digits of the REACH registration number to avoid sharing the identity of their supplier.

Substance Classification

For each substance named in this section, the classification according to CLP should also be provided. This classification enables you to classify your own product to CLP if you're using the mixture in your own formulations.

This subsection should contain:

  • The category codes.

  • The hazard classes.

  • The hazard statements.

For mixtures with many ingredients, and to save space on the safety data sheet, suppliers may only include the numerical codes for each hazard statement in this subsection.

If you find there are only numerical codes here you will find the full hazard statements in Section 16 of the safety data sheet. If, for some reason, Section 16 does not include the full list of hazard statements, then see this list <--ADD LINK, where you will find a list of every hazard statement that has been added to CLP.

Please note: For obvious reasons, the regulators will regularly add new hazard statements as new hazards are identified and described.

Concentration or Concentration Range

The concentration (range) of the hazardous ingredients listed in this section should be given here as a weight for weight percentage. If you are using the mixture for formulating your own products, this information is critically important because you can use it to establish whether the new product has a hazard classification itself.

If the supplier provides concentration ranges here, they should use the upper limits of the range of each hazardous substance so nobody is able to underestimate the hazards.


In the case of environmentally hazardous substances, you may also notice 'M-Factors' written in this subsection. An M-Factor is useful if you wish to use the mixture in your own formulations. It's not a legal requirement for suppliers to provide the M-Factor, but it is STRONGLY recommended.

Confused by the many pieces of information provided in those safety data sheets? Join the International Association for Chemical Safety's completely free health and safety academy now and take the Safety Data Sheet Awareness Certification™.

This article was originally published by the team over at Sevron Ltd and has been shared here with full permissions.

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