You should not leave a child unattended in a motor vehicle for any length of time. If children are trapped inside cars—especially in hot weather—they can suffer from heat exhaustion or heat stroke in a matter of minutes, leading to permanent disability or death. Heat stroke, also known as hyperthermia, can cause shock, seizures, irregular heartbeat, and heart attack, as well as brain, liver, and kidney damage. Leaving a child unattended in a car is also a form of neglectful supervision that is investigated by Child Protective Services.

In Washington State, leaving a child unattended in a motor vehicle is addressed under RCW 46.61.685, which makes it a traffic infraction for any person to leave a child under sixteen years of age unattended in a motor vehicle with the engine running or the vehicle moving. Additionally, if leaving the child in the car creates an unreasonable risk of harm or injury, the act could be considered a form of child neglect. Child Protective Services (CPS) may investigate such incidents as potential child neglect or abuse. In cases where a child suffers significant harm or is placed in substantial risk due to being left in a vehicle, especially under dangerous conditions such as extreme heat, the responsible adult could face more severe criminal charges, including reckless endangerment or even manslaughter in the event of a child's death. It is important to note that the specific circumstances of each case, such as the age of the child, the length of time the child was left unattended, and the conditions inside the vehicle (e.g., temperature), will influence the legal consequences.