Severino José da Silva, a 43-year-old valet responsible for maintaining the swimming pools at a gym in eastern São Paulo, informed the police that he had been receiving instructions via WhatsApp from one of the gym's partners for the preparation of chemical products. This statement came during an investigation initiated after the tragic death of swimming instructor Juliana Faustino Bassetto, who fell ill and died after a swimming lesson on Saturday, October 7. Surveillance footage revealed Severino handling a mixture intended for cleaning the pool water, while the partner allegedly directed all operations and merely responded with 'patience' upon learning about the victims.

The chemical preparation was not added to the pool directly; however, a bucket containing the mixture was left adjacent to the water, possibly leading to toxic exposure in the enclosed environment. Following the incident, Juliana was transported to a hospital but unfortunately did not survive. Her husband remains hospitalized alongside a 14-year-old teenager who was also affected by the incident. This situation raises significant concerns regarding the safety protocols in place at fitness facilities, especially those involving the handling of hazardous materials.