A suspected cluster of cancers among staff at a research laboratory was investigated by Santé publique France and its regional intervention unit in the Rhône-Alpes region (Cire), in collaboration with the relevant occupational health services. For the nine reported cases, the investigation focused on i) identifying the cases, ii) reconstructing the individuals’ career paths and occupational exposures within the laboratory, iii) conducting a literature review of the epidemiological characteristics of the selected cancers, iv) identifying known or suspected risk factors for these cancers, and v) assessing the carcinogenic potential of the products and equipment used. The analysis compared the occupational exposures of the cases with established and suspected risk factors for the identified cancers. The seven cases selected for the analysis present seven different types of cancer diagnosed between 2001 and 2014, five of whom have died. Compared with data from the French population, the cases were diagnosed with cancer well before the observed median age (except for one case). The most frequently identified exposures include polymers, nanomaterials, powders, particles, and dust, solvents, and the use of equipment employing X-ray (X-ray) beams. A comparison of the cases’ potential exposures with risk factors does not show a consistent pattern across all cancers. However, four cancer cases have potential exposure to X-rays, which is a proven risk factor for their types of cancer. This exposure is not established, however, based on the results of control measurements conducted during the period the device was used by the cases. Ultimately, the investigation did not identify a link between the seven cancer cases that occurred and a common occupational exposure within this laboratory. Furthermore, the young age of the cases and their limited time working in the laboratory prior to diagnosis do not support a link to occupational exposure. Santé publique France has recommended the implementation of rigorous monitoring of job positions and exposures for all workers in this laboratory, regardless of their status.