Health officials find themselves warning the public again about the dangers of leaving children in hot vehicles.

It comes after a toddler was found alone in a sweltering car on Saturday at White Oaks Mall.

Jane Harrington, an injury prevention specialist, at the London Health Sciences Centre, says children's body temperature heats up three to five times faster than an adult’s.

“Dehydration, heat exhaustion, where you're losing too much water and salt from your body is the first thing that’s going to happen. And you can really notice that if your children aren't drinking enough; they're not urinating enough. Heat stroke would be the last thing that would set in.”

Randy Laprise was the hero in the toddler’s case.

He spotted the 14-month-old boy in distress.

“I put my two children in the van and noticed in the car next to me, there was a baby inside the car, sweating and crying. All the windows were closed. No adults in sight,” he says.

Laprise called 911 and police arrived within three minutes. An officer broke a window with a baton, unlocked the door and retrieved the boy.

Some time later a family arrived. The man was arrested and has been charged with child abandonment.

Sgt. Glenn Hadley with the London police was on duty when the call came in.

“You don’t know what you're going into. It's not uncommon for us to arrive and find that there's nothing wrong with the child. But then the worst case scenario is also inevitably true and the last thing any of us want to see or any of us want to end our shifts with, is a child who's been seriously harmed or killed.”

The child was treated in hospital.

Police haven’t determined how long he was in the car.

Health officials say if the temperatures hit 25 degrees, you can expect the inside of a parked car to be 40 to 50 degrees.

“Your car heats up in ten minutes. Even if you roll down the window, it's not going to help,” says Harrington.

Laprise, a parent of five, says he's just glad he found the child when he did.

“It really bothers me. It gets me shaking a little bit. I can’t see how people can leave their kids in the car.”

The suspect will appear in court on July 8.