America's battle to keep children from dying in the backseats of hot cars is underway again after the nation's first death of 2024 in South Carolina.

Armani Shoemaker, 3, died May 3 after slipping out of his family home and into an unlocked car around noon in Columbia, according to a Richland County Sheriff's Department's report.

"You think of what happened in South Carolina and your heart just breaks," said Janette Fennell, the founder of Kids and Car Safety, an advocacy group that has tracked hot car deaths since 1990. "Now we're at over 1,000 kids and it doesn't have to be that way."

Over 90% of American households have a car, according to U.S. census surveys. An average of 35 toddlers die in hot cars every year, according to an analysis of Kids and Car Safety data.

"Kids are going to be kids and we're not going to re-engineer them," Fennell said. "It’s our responsibility as adults to make the environment safe, that’s exactly what we need to do here."

Reminders and radars: The tech available

Car makers, legislators and child safety advocates have been trying to reach a consensus on what technology measures can be adopted to save children's lives from sweltering car temperatures.

"The technology is out there, systems are out there that could prevent a great number of these deaths," said Peter Kurdock, general counsel for Advocates for Highway and Auto Safety. "That is one of the most frustrating issues about this."

But which technology to use is a big point of contention.

Car manufacturers tend to support "rear-seat reminder systems" which alert drivers to check the backseat after shutting off the engine; advocates say a radar system that scans for occupants is more accurate and proactive.

The Alliance for Automotive Innovation, the leading car manufacturer trade group, has a published commitment from 2019 to install reminder systems systems by the 2025 model year. Twenty-one automakers, from Ford and General Motors to Toyota and Volkswagen, signed on.

Advocates say the reminder systems fail in situations where kids, like Armani, entered cars on their own.

About 25% kids of who die hot car deaths entered on their own, according to Kids and Car Safety data. The group has also documented six hot car deaths in cars with reminder systems since 2019.

Feds miss regulation deadlines

The National Highway Traffic Safety Administration was supposed to have mandated reminder systems in new cars in November 2023, in accordance with the 2021 Infrastructure Investment and Jobs Act.

But the deadline came and went.

A spokesperson for the federal agency said research necessary to issue the regulation was still underway. The 2021 law calls for a reminder system but the spokesperson confirmed the agency was also researching occupant detecting technology.

"The agency is also conducting studies on the potential retrofitting of existing passenger motor vehicles with rear-seat alert systems," the statement said. "Furthermore, NHTSA is continuing to identify and test rear seat occupant detection systems as they become available."

Mary "Missy" Cummings, a former senior safety advisor to the federal agency, said the regulation likely hasn't come out because of other agency priorities. "The tech is there," she said in an email, noting it's available in some cars. "This is clearly a political/bureaucracy problem."

Advocates said they expect a preliminary rule in August. The agency did not immediately confirm.

The radar technology is already being added to cars in Europe, Kurdock said, and is available in some cars sold in the U.S. Among those is Hyundai, which announced it would begin installing "Ultrasonic Rear Occupant Alert" systems beginning with its 2022 models.

Russell Datz, a Volvo spokesperson said the company's EX90 model would have radar technology to detect occupants and will be able to detect children who enter on their own, as long as the main battery has enough charge.

Advocacy group warns: 'It’s not if, but how many and when'

Until radar technology becomes widespread, Fennell said she expects to have to document more cases like Armani's over the summer.

"It’s not if, but how many and when," she said.

Over 1,050 children have died in hot cars nationwide since 1990, according to Kids and Car Safety, and over 7,300 survived with injuries. Almost 90% of children who die are 3 or younger. Most were unknowingly left by a parent or caregiver.

"We know right now there are parents who love their babies and by the end of the summer they won’t be with them anymore," Fennell said.

Deaths can happen in any month of the year, she said. A 1-year-old left in a car outside Atlanta in October was the last person to die in a hot car in 2023; the first was a 2-year-old left in a car in Louisiana in February, according to Kids and Car Safety data.

Since 1990, Texas had the most deaths with 156. Only Alaska has not recorded a death, according to the group's data.

From 88 to 140 degrees in 60 minutes

The temperature inside a car on a 73-degree day will shoot up to 100 in 25 minutes, according to the National Weather Service.

The high in Columbia, South Carolina on May 3 was an unseasonably warm 88 degrees, according to weather data. At 88 degrees, a car will heat up to nearly 140 in an hour.

The local National Weather Service office issued a warning at 8 a.m. about the dangers of hot cars for children. “NEVER leave people or pets alone in a closed car,” it read.

Armani was last seen at 11:30 a.m. “wearing pampers diapers with beaded braids,” according to the Sheriff's report. "She wasn't in the car for very long," said Deputy Jamie Burton, before deputies found her at 1:48 p.m.

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Tips to avoiding a tragic heat accident with your child

Here's what experts say you should do to prevent a tragic accident:

• Place a visual reminder that your child is with you, such as a diaper bag, in the front seat.
• Put an important item you need to start your day in the back seat, such as your cell phone, and make it a habit to always open the back door when you get out of the car.
• Ask your childcare providers to call you if your child isn't dropped off as scheduled, because parents sometimes think they have dropped their child off and go to work, accidentally leaving them in their car seats all day.
• Fennell also said a tip she likes to give is to keep a stuffed animal in your child's car seat at all times. When your child is put in the seat, the stuffed animal goes on the front passenger seat as a visual reminder.

Contributing Jeanine Santucci, USA TODAY