Reports of unusual health events in the workplace received by Santé publique France are becoming increasingly frequent, and addressing them is often complex. These include suspected clusters of cancer or other diseases, unexplained collective syndromes, or unexpected workplace exposure to hazardous agents.

To ensure a coordinated, unified, and rapid response, the French Institute for Public Health Surveillance has established and is developing a regionalized system known as GAST—Occupational Health Alert Groups. In each region, the GAST is tasked with managing these health events deemed unusual, suspected, or observed in the workplace and reported to the Regional Health Agency. The work involves validating and evaluating reports, deciding whether to conduct an investigation if necessary, and formulating recommendations regarding actions to be taken.