"Bottled water in your car is very dangerous!" On the Ellen Show, Sheryl Crow said that this is what caused her breast cancer. Not only is it a fire hazard to leave bottled water in your car, but the direct heat and UV rays can cause harmful chemicals to be released into the water. High levels of dioxin in breast cancer tissue results from drinking water left behind in cars. This chemical is released when the heat reacts with the plastic of the bottle, thus making the water harmful once consumed.
Dioxin is a toxin increasingly found in breast cancer tissue. So please be careful and do not drink bottled water that has been left in the car.