Occupational diseases (ODs) encompass all illnesses that physicians—and occupational physicians in particular—deem to be related to work and that are not covered by the Social Security system. They are not included in the Social Security’s annual statistics. As part of its mission to conduct epidemiological surveillance of occupational risks, Santé publique France (SpF) has established, in partnership with the Medical Labor Inspection (IMT) of the Ministry of Labor, a system for the epidemiological surveillance of ODDs. In Brittany, the program has been jointly conducted since 2012 by SpF, the IMT of the Regional Directorate for Enterprises, Competition, Consumer Affairs, Labor, and Employment (Direccte) of Brittany, and the Regional Health Observatory (ORS) of Brittany. The MCP surveillance program relies on the voluntary participation of occupational physicians and collaborating physicians in the region, who, with the support of nurses, report all cases of MCP encountered during their consultations with employees twice a year for two consecutive weeks (known as “MCP Fortnights”). This program respects the anonymity of the employees seen. In 2024, 1,133 employees were seen during consultations over the two fortnights in Brittany.