This sociological research examines how public health frameworks shape urban commons through Bagnoli's waterfront study (Naples, Italy). Once Balneolae, a thermal destination renowned since antiquity, then an industrial site, now a Site of National Interest (SIN) due to contamination, it typifies how public health drives urban commons transformations. The site's cruciality stems from its designation as National Priority Contaminated Site after Italsider’s shutdown. While institutional fragmentation blocks environmental regeneration, the area faces new public healt risks due to rising nightclubs’ nuclei. This study systematizes literature on night-time economy (Hobbs et al,2000) and new-commons (Hess,2008) in a postindustrial scenario, exploring tensions between commodification and de-commodification of public space via public health. The methodology combines secondary source analysis, field observation, and semi-structured interviews using MyMaps for digital mapping, Epicollect5 for field data collection, and MAXQDA for interview analysis. The results revealed critical issues related to noise pollution, mobility and public space accessibility. Observations documented systematic violations of the noise limit prescribed by medical literature, WHO and the European Environmental Agency; Emergency assets also experienced delayed response times in loisir districts. This study identifies emerging forms of resistance through two urban commons recognized by Naples Municipality Villa Medusa and Lido Pola, representing alternatives to commercial waterfront use, directly opposing privatization via practices of solidarity. Villa Medusa spawned the Popular Observatory on Remediation of Bagnoli-Coroglio SIN, which professionalizes community struggle while providing a tool for democracy through environmental health knowledge's commoning. This initiative is accompanied by informal “Metal Beach” practices where citizens consciously reclaim the polluted Coroglio shore, using the evocative name as symbolic resistance demonstrating how communities negotiate health risks while asserting their right to the city. This case contributes to debate on postindustrial waterfront regeneration, posing insights for policy makers and activists. It emphasizes how public health challenges require more inclusive and participatory approaches in urban planning that consider both legacy contamination and emerging health threats, pursue a dynamic balance between economic opportunities and spatial justice. Keywords: Waterfront, Night-time economy, New-commons, Right to the City, Public Health
