A police officer in Forsyth County, Ga., demonstrates the danger of leaving children in a hot car in this video posted by the Forsyth County Sheriff's Office. (Forsyth County Sheriff's Office)

Jan Null began tracking heatstroke deaths of children left in cars 15 years ago. Since then, 682 children have died in hot cars.

Half of them were under 2 years old, meaning they would never have the chance to read a book, attend school, have first-date jitters or explore their passions.

“Every one of these [deaths] can be prevented,” Null — a certified meteorologist and professor at San Jose State University — told The Washington Post in an interview Sunday evening.

The two latest deaths occurred over the weekend.

On Friday, 4-year-old Samaria Motyka died after being left in a sealed car in Pennsylvania for several hours.

An unnamed woman, who was reported to be in a relationship with Samantha’s father but was otherwise unrelated to the child, was supposed to take the girl to a day-care center. Instead, she drove to her workplace in downtown Williamsport, forgetting Samaria in the backseat for several hours, the Associated Press reported.

Temperatures soared to 97 degrees in Williamsport that day, according to The National Weather Service.

The assistant chief of the Williamsport Police Department, Timothy Miller, said the death appears to be a tragic accident, though officials are still awaiting the results of toxicology reports to determine if negligence was involved.

Two days later, a 3-year-old was left in a 2006 Honda Pilot outside a church in Dallas, while the boy’s father attended a religious service. Temperatures reached 98 degrees Sunday.

Reng Om, a member of the Matu Christian Church, was at the Bible study when the unnamed father realized he’d forgotten his son and rushed out to the parking lot. Minutes later, Om told WFAA, the father walked back in cradling the unresponsive child’s small body in his arms.

The child was pronounced dead at Baylor Medical Center White Rock. Police are investigating.

Thus far, 21 children have died this year from being left in hot cars and many of the situations were particularly horrifying. A 2-year-old left in a car in Annandale, Va., for seven hours in April suffered second-degree burns and had a body temperature of 107 degrees when finally brought to a hospital. In June, a father in Melissa, Tex., was charged with manslaughter for placing his 6-month-old daughter in the refrigerator after leaving her in the car for about four hours.

Null, who posts the data he collects on noheatstroke.org, said the number of children dying from vehicular heatstroke each year has remained fairly steady since he began tracking the data in 1998.

“You drop the numbers into Excel, you hit the trend line, and you basically get a straight line,” Null said.

He attributes this, at least in part, to a lack of awareness perpetrated both by lawmakers and, until recently, the media.


Courtesy Jan Null, CCM, Department of Meteorology and Climate Science, San Jose State University

“There’s only 20 states that have laws against leaving a child unattended in a car,” he said, adding that Florida’s law allows children to be left in a car for 15 minutes (which he said “could be a death sentence,” noting that death can occur in 20).

Likewise, he said the media didn’t pay much attention to vehicular heatstroke until the 2014 story of Justin Harris leaving his 22-month son in a rear-facing car seat went viral and took over the 24-hour news cycle.

Since then, Null has noticed increased media attention on hot car deaths, which he and many other advocates hoped might lower the number of instances.

That case really raised the media interest,” he said. “A positive unexpected consequence.”

The media attention seemed to be working for the last two years. Since 1998, an average of 37 children have died annually from being left in hot cars. In 2013, 44 children died in this manner.

That number dropped to 31 in 2014 — the year of the Justin Harris story — and 24 in 2015.

Unfortunately, Null called last year an “anomaly.” With 21 recorded deaths so far in 2016, Null sadly noted, “We’re right about where the average would be in the last week of July.”

Before the late 90s, the number was actually much lower — an average of 12 deaths per year. But Null said with the inclusion of air bags in front seat, which aren’t safe for children, and the advent of rear-facing child-seats, the numbers “took a huge stair-step up in the late 90s and have stuck there” because parents can more easily forget their children in the car.

The deaths of most of these children can be blamed on sheer forgetfulness.

In addition to simply tracing how many children die each year, he also records the circumstances surrounding each incident.

Fifty-four percent of the 682 recorded deaths in the last 15 years occurred when a parent or caretaker unintentionally forgot a child in the car. Twenty-eight percent occur when a child accidentally locks himself inside of a car (which often included child lock features in the back seat), and 17 percent occur when someone intentionally locks a child in the car. The circumstances in the remaining one percent of cases are unknown.

“A whole range of people can get distracted and leave their child in the car,” Null said. “It can happen to anybody.”

He then directed The Post to an infographic on his site, which listed a short sampling of the aforementioned caretaker’s occupations. Dentist, judge, lawyer, waiter, coach and firefighter are among them.

One of the things these caretakers may not fully understand is how quickly a car heats up — and how hot it can get. Null began studying this exact phenomenon in 1998, after receiving a call from a local journalist. The reporter was working on a story about a boy who died from heatstroke after being left in a car in San Jose, Calif., for two hours on an 86-degree day.

“How hot did it get in that car?” Null was asked, only to realize he didn’t know. He decided to find out, and what he discovered surprised him.

“I was surprised by how rapidly the temperatures rose and ultimately how hot they go,” Null told The Post. “[The car] is basically a greenhouse, and it’s a very effective greenhouse.”

Heat stroke occurs when the body reaches 104 degrees, according to the Mayo Clinic, and Null said at 107 degrees, cells inside the body’s internal organs shut down. It can happen one organ at a time, but he said, “there’s generally a cascade of organs shutting down.”

In addition, a child’s body heats up three to five times faster than an adult’s, according to the Seattle Children’s Hospital.

During summer, this means a car’s internal temperature doesn’t often have to rise all that much — the air was already 97 and 98 degrees in the two deaths from the weekend. But it also can reach deadly temperatures easily in the fall or the spring.

“We all know that on hot days, cars get really hot,” Null said. “What I think people don’t really grasp is how hot they get on moderate days.”

On a sweltering day, opaque objects in cars, like dark dashboards and seats, can heat up to temperatures over 200 degrees, and then warm up the air around them. Here's a look at how fast those conditions affect the temperature of the air trapped in a car. (Courtesy GM and Jan Null, San Jose State University)

What most don’t understand is the sunlight isn’t directly heating the air inside a car. Instead, the sun’s shortwave radiation slips in through the windows and heats the objects in the car, including the dashboard, steering wheel, arm rests, child-seat, etc. These warm quickly, then heat the air in the car by means of conduction and convection.

“On a moderate day, a dashboard or a black steering wheel is generally 200 degrees,” Null said.

In a paper he published in Pediatrics with Dr. Catherine McLaren and Dr. James Quinn, Null found that on days when the external air temperature exceeds 86 degrees, the air in a car can reach 154 degrees. The air temperature inside a car rises, on average, 40 degrees with 80 percent of that occurring in the first thirty minutes. Other experts agree. Christopher Haines, director of pediatric emergency medicine at St. Christopher’s Hospital for Children in Philadelphia, told WedMD that up to 70 percent of the increase occurs in the first half-hour.

Most notable, perhaps, is that the air temperature outside the car does not affect how quickly the temperature inside the car rises.

As Safe Kids Worldwide chief executive Kate Carr told CNN, “A car can heat up about 19 degrees in as little as 10 minutes, and we’ve seen heat stroke deaths recorded when the temperature is in the 60s.”

And the old trick of cracking the windows to keep the car cooler? It doesn’t appear to help enough to be significant. The study found that the temperature inside a car with cracked windows rises, on average, 3.1 degrees per five-minute interval, rather than 3.4 degrees.

That’s why heatstroke deaths have been recorded in every month, including December, January and February.

As summer temperatures rise, here are a few simple tips from the National Safety Council to keep kids safe. (Tom LeGro/The Washington Post)

The National Safety Council advises never leaving a child in a car, regardless of the weather, and to place something you need — such as a purse or wallet — in the back seat, which will force you to check for it before exiting the car. Finally, leave the doors locked when outside of the car, so a curious child can’t climb back in.

Finally, pedestrians should always call 911 if they see a child locked inside of a car.