Company 3 responded to a vehicle fire on Chalet Drive. Upon arrival, found two vehicles fully involved in flames in a residential driveway. Fire in both vehicles was extinguished. No extension was made inside the residence, only heat damages to a window and the vinyl siding. Bystanders noticed smoke coming from the back of the van and spread rapidly, extending to a nearby vehicle. After the fire was extinguished, assorted pool tools, chemicals and lithium battery cells were located in the area or origin. One person treated and transported for smoke inhalation.