Gas leak during swimming pool maintenance at Kaisaris Educational Institutions in Koropi

On the morning of November 11, 2026, an incident involving a chemical gas release occurred at the Kaisaris Educational Institutions in Koropi, Greece. The event was triggered during swimming pool maintenance when chlorine-based substances were mixed in a container, releasing fumes into the school area. Ilias Kaisaris, representative of the school, stated that the reaction occurred within a container and that no chlorine entered the pool water itself.

Emergency services, including the Fire Department and the National Centre for Emergency Care (EKAB), were immediately mobilized. The primary school and kindergarten buildings were evacuated as a precautionary measure. According to reports from the Cyprus Times, 13 students were transported to the Aglaia Kyriakou Children's Hospital, while 13 staff members were taken to Sotiria Hospital. Two maintenance workers were treated at the Koropi Health Centre. Another student was released directly to their parent. While reports on the number of hospitalized adults differ slightly between sources, all affected individuals are reported to be in stable condition.

The Fire Department is currently investigating the circumstances of the incident to determine the exact cause of the chemical reaction. School operations were adjusted following the evacuation, with students moved to the high school and gymnasium buildings as a safety precaution.