Uncertainties remain regarding the risk posed by environmental exposure to dioxins for the general population. Our team therefore conducted a research program focused on the municipal solid waste incineration plant (MSWIP) in Besançon, which had emitted high concentrations of dioxins. In an initial study conducted from 1998 to 1999, a highly significant and identical spatial cluster (containing the MSWIF) was identified for non-Hodgkin lymphomas (NHL) and soft tissue sarcomas (STS) diagnosed between 1980 and 1995. The standardized incidence ratios were 1.27 (p < 10⁻⁴) and 1.44 (p < 0.01), respectively. The second phase involved two case-control studies (conducted from 2000 to 2002), comparing incident cases of NHL and STM with controls randomly selected from the population census. Dioxin exposure was derived from a first-generation Gaussian atmospheric dispersion model. The risk of developing NHL was found to be 2.3 times higher for individuals residing in the area most exposed to dioxin fallout (95% confidence interval 1.4–3.8), while no significant risk was observed for STM. The third phase (2002–2004) focused on validating exposure by measuring dioxins in the soil. An increasing relationship between the four exposure classes modeled based on atmospheric dispersion and dioxin concentrations was found, but only in a simple topography (northeast of the MSW incinerator). Although MSW incineration plants are not considered a major source of dioxin exposure, the consistency of the various results supports the hypothesis of an association between environmental dioxin exposure and the occurrence of NHL in populations residing near an MSW incineration plant. (R.A.)