GHS Update: New Clarifications Proposed for Mutagenicity Hazard Class

On 19 November 2024, the Sub-Committee of Experts on the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) published proposed clarifications to the classification criteria for germ cell mutagenicity submitted by the Informal Working Group (IWG). 

These clarifications on mutagenicity classification were presented at the forty-seventh session of the Sub-Committee (UN/SCEGHS/47/INF.19) from 4 to 6 December 2024. 

Background 

Under the current GHS framework, the classification criteria for the mutagenicity hazard class focus only on reproductive cells which are also known as germ cells. The criteria have excluded somatic cells, which are present throughout the body. However, a mutation in somatic cells also poses a risk to human health. 

As of now, the GHS lacks classification information for somatic cell mutagenicity, highlighting the need for clarification on this issue. As a result, somatic mutagens may be classified as Category 2 despite their capacity to cause mutations similar to those in Category 1.  

Clarifications submitted by the IWG  

The IWG proposed two clarifications regarding mutagenicity classification: 

1. Establish two separate hazard classes - one for germ cell mutagenicity and another for somatic cell mutagenicity. 

2. Maintain a single hazard class for both germ cell mutagenicity and mutagenicity, but include separate hazard statements for each. 

Next Steps 

After the final review of all information related to the revision of the classification criteria for Category 1A/1B or Category 2 of the Germ Cell Mutagenicity Class and the corresponding testing methods, the Sub-Committee will consider this in its work programme for 2025-2026.