CHESTERFIELD, (WRIC) — An investigation by the Chesterfield Fire Marshal’s office has revealed that a hazmat incident earlier this week that sent 11 people to the hospital was caused by a pump malfunction in the neighborhood pool.

Fire officials told 8News that parents became concerned after children became nauseous and began having respiratory issues.

Now, fire officials say “preliminary information” indicates that pool staff were not responsible for the incident – instead pointing to a malfunctioning chemical pump that flooded the pool system with too much pool chemical.

One mother – who asked to remain anonymous – was at the pool with her five children, who ranged in age from eight years to four months. She said they inhaled a “powdery substance” and began choking, after which she drove them to Chippenham Hospital for treatment.

Hours later, she could still be heard coughing on the phone.

Four children and one adult were taken to local hospitals by ambulance, but officials say none suffered life-threatening injuries.

Additionally, 25 people were hosed down by emergency responders at the scene, and evaluated by medics who took their blood pressure and checked their breathing to ensure they didn’t need immediate medical attention.