Prolonged heat exposure may increase the movement of certain chemicals from plastic packaging into the water. Because of this, it is generally better not to drink bottled water that has been sitting in a very hot vehicle for hours.
Other everyday items can also become dangerous in a hot car. Aerosol cans, disposable lighters, canned drinks, and loose batteries may leak, burst, or become damaged when exposed to extreme temperatures.
Medications should also not be stored in a hot vehicle because heat can reduce their effectiveness. During summer, it is safer to remove heat-sensitive items from the car rather than using the vehicle as long-term storage.
