The GHS contains harmonized classification criteria and hazard communication elements. In addition, guidance is provided to assist countries in the development of tools for implementation of the GHS.

The GHS is designed to allow for self-classification by the pesticide industry. Furthermore, the GHS is intended to facilitate the work of regulatory bodies and to reduce the administrative burden, both for government authorities and for the industry.

The following elements are included in the GHS:

The GHS refers to "substances" and "mixtures". In pesticide registration, a "substance" generally corresponds to the active ingredient or active substance of a pesticide; a "mixture" corresponds to the formulated pesticide product.

However, data on the formulated pesticide product (the mixture), submitted as part of a registration dossier, is usually limited to acute health effects. Therefore, possible long-term effects for all constituents of the pesticide product, not only for the active substance, need to be assessed for classification purposes.

The procedures for classification and labelling of a pesticide product can be seen as a two-step process, where the first step consists of the hazard classification and the second of the preparation of the label.

Step 1: Hazard classification

Hazard classification considers only the intrinsic properties of substances or mixtures. It incorporates the following main activities:

• identification of relevant data regarding the hazards of a pesticide active ingredient or formulated product;
• subsequent review of those data to ascertain the hazards associated with the pesticide active ingredient or product; and
• a decision on whether the pesticide active ingredient or product fulfills the hazard classification criteria.

Once a pesticide product is classified, the likelihood of adverse effects (risk) may be considered as part of different types of regulatory action, e.g. the elaboration of use instructions or the requirements for risk reduction measures.

The classification criteria for substances and mixtures are presented in Parts 2, 3 and 4 of the GHS, each of which is for a specific hazard class or a group of closely related hazard classes. For most hazard classes, the recommended process of classification of mixtures (the formulated pesticide product) is based on the following sequence:

1. Where test data are available for the complete mixture, the classification of the mixture will always be based on those data;
2. Where test data are not available for the mixture itself, then bridging principles, included and explained in each specific chapter, should be considered to see whether they permit classification of the mixture. Bridging may also be applied when test data conclusively show that no classification is warranted;

In addition, for health and environmental hazards,

3. If (i) test data are not available for the mixture itself, and (ii) the available information is not sufficient to allow application of the above mentioned bridging principles, then the agreed method(s) described in each chapter for estimating the hazards based on the known information will be applied to classify the mixture.

In most cases, it is not anticipated that reliable data for formulated pesticide products will be available for hazard classes germ cell mutagenicity, carcinogenicity and reproductive toxicity. Therefore, for these hazard classes, pesticide products will generally be classified based on the available information for the individual ingredients of the product. The classification may be modified on a case-by-case basis based on available test data for the formulated pesticide product, if such data are conclusive as described in each chapter.

Step 2: Preparing the label

This step includes the allocation of the following:

• Label elements
• Hazard pictograms
• Signal words;
• Hazard statements
• Precautionary statements and pictograms
• Product and supplier identification
• Multiple hazards and precedence of information
• Arrangements for presenting the GHS label elements
• Special labelling arrangements.

As many countries have placed the responsibility on the applicant to submit a proposal for classification and a draft label for the pesticide product as part of the dossier, the registration authority will have to check the accuracy during dossier evaluation.

In addition to ensuring harmonization between the hazard information, the label and the safety data sheet, the consultation of other data sources may also be considered.

The FAO/WHO Guidance on good labelling practices for pesticides provides recommendations on the labelling of pesticides. The guidance stresses the importance to adopt the GHS and to use it for pesticide labelling, but it also provides additional guidance for regulatory authorities to consider when reviewing a pesticide label, e.g. on the application of colour bands.