A method for assessing the carcinogenicity of work processes

While the regulatory classification of carcinogenic chemical substances and products is based on criteria defined by the European Regulation on Classification, Labelling and Packaging (the CLP Regulation), this is not the case for processes and circumstances of exposure that can cause cancer in workers.

In the expert appraisal it recently carried out, ANSES considered that any task, organisation or working condition exposing workers to chemical, biological or physical agents should fall within the definition of a potentially carcinogenic work process. Some examples include work such as welding or sanding operations that emit harmful gases, particles, or dust. Exposure to the sun's UV rays and night-time activities also fit in this definition.

Providing a scientific basis for defining carcinogenic processes

To make up for the lack of criteria in both Europe and France, the French Directorate General for Labour asked ANSES to propose a methodology for identifying carcinogenic processes on a scientific basis. The aim of this identification is to support the inclusion of these processes in the Order establishing the list of carcinogenic substances, mixtures and processes as defined in the French Labour Code.  

The inclusion of processes in this Order will improve the protection of exposed workers. Indeed, when a process is recognised as carcinogenic, assessment and prevention measures must be put in place, along with reinforced individual medical monitoring. Employers must also replace carcinogenic processes whenever possible.

A methodology based primarily on the results of international studies

In order to establish a methodology for identifying carcinogenic processes, ANSES’s working group began by researching the various organisations that classify the carcinogenicity of processes or exposure circumstances. Apart from the International Agency for Research on Cancer (IARC), whose work is internationally recognised, only two institutions were identified that have a scientific methodology and experience in classifying the carcinogenicity of processes: one is in the Netherlands and the other in the United States.

To determine whether a process is carcinogenic, the expert group recommends first looking at whether it has been classified by the IARC. If it has, a literature search should be carried out to identify the studies published following this classification, in order to take account of the latest data. The aims include determining which organs are affected and ascertaining the level of evidence, i.e. the degree of certainty surrounding the causal link between exposure to the process and the onset of cancer.

Otherwise, a specific case-by-case assessment

If no assessment is available, an in-depth expert appraisal of the process will have to be entrusted to a working group specifically set up for this purpose. This will involve comparing the available carcinogenicity data in humans and animals, to ensure that they meet the classification criteria used in the CLP Regulation for carcinogenic substances, including an assessment of causality, as implemented in particular by the IARC. 

The methodology proposed by ANSES has already been used to recommend adding work involving exposure to welding fumes  and work involving exposure to various active ingredients of cancer drugs to the list of processes recognised as carcinogenic. The Agency is currently working to identify the processes that should be assessed as a priority to determine whether they are carcinogenic. This work should be published in 2024.