Introduction: This report supplements the report titled "The Relevance of a Biomonitoring Study Following the Fire in Rouen on September 26, 2019" (Fréry et al. 2021). It aims to shed light on whether or not the environment remains contaminated as a result of the fire at the Lubrizol and NL Logistique facilities. In this regard, the issue of environmental contamination following the fire by persistent organic pollutants—specifically polycyclic aromatic hydrocarbons (PAHs) or dioxins—as well as by lead is raised. The purpose of this document is to provide an overview of all available reports and to supplement the summarized findings with a complementary analysis. Method: Santé publique France requested that INERIS compile a database containing all available environmental measurement data and create a dynamic mapping application. The information available in the various reports and assessments published after the fire—most of which were commissioned by the prefecture—was examined with regard to the presence of persistent organic pollutants in the food chain. This work was supplemented for two representative substances from the families of interest (fluoranthene and OCDD—octachlorodibenzodioxin) with a descriptive analysis of the available data for two matrices (soil and foodstuffs). The descriptive analysis aimed to determine, if applicable, for these two substances in relation to the fire: a spatial gradient of concentrations in soil; a temporal and/or spatial gradient of concentrations in the food chain; a temporal variation between 2019 and 2020 in food concentrations; and correlations between the matrices (soil/plants). Results: Following the analysis of the available data and the supplementary descriptive analysis (for OCDD and fluoranthene in soil and foodstuffs), there is no evidence to conclude that contamination linked to the fire has been observed, distinguishable from historical pollution. Regarding comparisons between the food matrix and soil, it was not possible to test for potential correlations between the soil matrix and the food matrix due to insufficient data. Regarding trends and changes between 2019 and 2020, it was not possible to identify trends or observe changes between 2019 and 2020 due to a lack of available data. Recommendations: Following this supplementary report, recommendations were presented for situations where public health issues might arise in the aftermath of an accident.