Following a public health alert issued by general practitioners, an initial analysis of glioblastoma cases in the municipalities of Salindres and Rousson was conducted for the period 2006–2010 using data from the National Histological Registry of Primary Tumors of the Central Nervous System (RnhTPSNC). Since additional cases were identified by the RnhTPSNC after 2010, an analysis of the local and departmental incidence of glioblastomas over an additional 5-year period (2011 to 2015) was conducted to monitor changes in the epidemiological situation in this area. It highlights a significantly higher number of cases in the two municipalities over the 2006–2015 period compared to the expected number of cases, using the Gard department as a reference. Investigations were conducted with the ARS and the DREAL to identify environmental factors in this area that are known from the scientific literature to potentially pose a risk for the development of glioblastoma. This progress report presents the results of the analysis of glioblastoma surveillance data in the municipalities of Salindres and Rousson from 2006 to 2015, as well as the initial environmental investigations. It also offers avenues for further investigation.