Assisi Mayor Orders Red Zone After Chlorine Gas Leak in Private Pool

On the afternoon of 1 August 2026, a chemical incident occurred in the technical room of a private swimming‑pool in Porziano, a locality in the mountainous area of Assisi, Umbria. An improper mixing of materials triggered an exothermic reaction that released large amounts of highly toxic chlorine gas.

Mayor Valter Stoppini issued an urgent contingency ordinance to protect public health. A red zone was established within a 100‑metre radius where outdoor presence of people, pets and livestock is prohibited and access is limited to emergency responders. Vehicle traffic is allowed only with windows fully closed and air‑conditioning or ventilation systems turned off. Within a 500‑metre “attention area,” residents must keep windows and doors shut, suspend outdoor activities and refrain from using air‑conditioning that could draw in external air. Firefighters, ARPA Umbria technicians and health‑care personnel responded promptly to contain, monitor and secure the area.