The incident occurred when students, engaged in a painting activity, attempted to clean up spilled material. Adding bleach to a bucket containing residue of another liquid product generated a chemical reaction that produced a small toxic cloud. The Councillor for Education, Emili Gilabert, described it as an "incident resulting from an accidental mixture".

Emergency services received the alert at 12:08 PM. Two of the affected individuals were taken to the Arnau de Vilanova hospital in Lleida, while five others were treated at the CAP in the capital of Urgell with mild symptoms. Five units from the Generalitat Firefighters, SEM ambulances, and Local Police patrols responded to the scene.

As a precaution, the entire building, which also houses the adult education center, was evacuated. Firefighters ventilated the facilities, completing the task around 1:00 PM. Subsequently, those unharmed were able to resume classes.

This incident is reminiscent of another that occurred a month ago, on April 24th, at the municipal indoor swimming pool in Tàrrega, where nine people were injured by a similar chemical reaction during water treatment, leading to the evacuation of approximately 60 people.