The incident took place at approximately 10:30 AM in the school playground, located in the Pla de l'Estany region. A bottle used for a chemical reaction exploded, causing a blast that affected three fourth-grade primary students.

The two children allowed to return home are a boy and a girl, both 9 years old. They were originally taken by SEM emergency services to Josep Trueta and Vall d'Hebron hospitals. A third student remains hospitalized in serious condition at the burn unit in Barcelona after being airlifted by medical helicopter.