First responders say parents and caregivers can't be reminded enough to never leave children unattended in a vehicle.
Unfortunately, there's a new trend that involves kids getting themselves trapped in vehicles.
San Antonio Fire Department Chief Charles Hood said children are getting into unlocked vehicles to look for a toy, find a place to hide or play.
The Fire Department, in cooperation with other emergency medical services crews, held a mock drill Wednesday afternoon in which they responded to a heatstroke call.
Crews will do whatever it takes to gain access to a child left unattended in a car, whether or not the engine is left running.
"If this tragedy happens, it's going to destroy your family," Hood said. "A lot of times, we're able to resuscitate the child and get their heart started, but their brain has suffered some type of irreversible damage that is going to impede them for the rest of their lives."
Hood said San Antonio hasn't seen any hyperthermia or heatstroke deaths involving children in nearly a decade. But families in other communities have been affected by what many call an avoidable tragedy.
"Texas leads the country in the total number of deaths," said Lillian Liao, University Hospital pediatric trauma and burn director. Liao recommended trying to open the car yourself and then calling 911 if you see a child left unattended.
Often times, it's suggested that parents and caregivers leave something of importance next to a child -- such as a wallet, purse, cell phone or keys -- to ensure they'll check the back seat.
Temperatures inside vehicles quickly rise above outside temperatures. Children are particularly at risk for heatstroke because their bodies heat up three to five times faster than an adult's body, according to Safe Kids Worldwide.
"One child lost anywhere in the country is devastating enough for us," Hood said.
Since 1998, more than 660 children across the U.S. have died from being trapped in a hot car. On average, 37 die each year and hundreds are rescued.