Last month, I sent my soon-to-be first-grader off to his first summer camp. The local day camp incorporates pretty much everything a busy, working parent could want: They pick up at our door, ferry the kids off to a regional park 10 miles away, run them hard outside all day long, then drop them off at home happy, dirty and exhausted. But when the first day of camp arrived, the door-to-door transportation that sounded so appealing suddenly left me riddled with doubt.

A college student driving a brand new, 12-passenger van pulled up to my driveway. My son and three other children, all between 5 and 7 years old, climbed inside, fastened their seat belts, and threw us huge grins. As the other parents bantered and waved goodbye, I felt my stomach clench. Despite earlier guarantees from camp administrators that the van seats were certified safe for children 5 and older, my son and the other small campers were swallowed by their seat belts — shoulder belts hitting at their necks, lap belts laying across the soft part of their bellies. I waved goodbye and then picked up the phone and called Judy Slattery, a child passenger safety technician (CPST) and trainer in Southern California.

When I described the situation, Slattery was appalled but not surprised. “They’re doing this at day camps across the state,” she said, “and all of us in the industry are concerned about these kids.” She said that she and other child-safety specialists across California get phone calls about this problem every summer. And, she told me, the camp administrators were wrong: In California, state law requires children younger than 8 to be restrained safely in any passenger vehicle, which means they must be in a car seat or booster. The California Highway Patrol, which regulates and enforces passenger safety in the state, told me the same.

The problem isn’t limited to California. It’s happening across the country. “You could call someone in every state and they’d tell you that it’s a problem," said Bob Wall, a Fairfax, Va.-based global safety advocate for Nuna Baby, a car seat and baby gear company.

Lani Harrison, of Los Angeles, experienced a situation similar to mine with her 6-year-old. The difference is that she knew the law backward and forward. Until last month, Harrison was vice president of Car Seats for the Littles, a group of CPSTs and other experts from the United States and beyond, and she’s spent years educating caregivers about car seat safety. Each summer, she says, she’d receive 50 to 75 queries from across the country about transport vans lacking boosters or other safety restraints. And that’s just the people who sense something’s wrong. “So many people don’t even know to ask,” she said.

(Not sure whether your child needs a booster seat? Here’s a five-step test to help you figure it out.)

Many summer camps and other programs — from after-school taekwondo studios to church youth groups — are using large passenger vans to provide unparalleled convenience and opportunity for busy kids of busy parents. But seat belts in these vans are made for an average adult’s height and mature skeleton. In an accident, shoulder straps cutting across a child’s neck can cause abrasions and temporarily cut off their airway. And a poorly positioned lap belt can slice right into a child’s stomach.

Five-point harnesses and booster seats position a lap belt over the top of the hip bones, low and flat against the thighs, so the child’s bones absorb the impact. When the lap belt sits high up on a child’s belly, it can push into their internal organs. “It’s called seat-belt syndrome,” Wall said. “In an accident, it cuts into the belly and impacts intestines or stomach or liver, and all kinds of things can happen. It can be fatal.”

Slattery didn’t mince words. “That’s how you end up with a 7-year-old with a colostomy bag,” she said.

To make matters worse, because the transport vans have such a high center of gravity, they’re at higher risk of rollover than any other vehicle on the road. The National Highway Traffic Safety Administration prevents car dealers and any other company that sells new passenger vans from selling them to public schools as student transport. But they can’t prevent sales of used vans, and those sales are rampant.

The trade-off between safety and convenience is one that so many groups are willing to make, simply because the vans carry so many people. But increased passenger capacity doesn’t mean they should be used like school buses. “People think of them like a bus when they really aren’t,” says Denise Donaldson, editor of Safe Ride News. “They don’t have the extra protection that you get on a school bus” — padded seats and a safety tactic known as compartmentalization, which protects its charges the way an egg carton protects its eggs. “It’s important not to put the vans in any type of the same category as a school bus.”

Yet that’s just what so many programs are doing. Some provide booster seats, but then stop doing so after children hit their state’s legal age limit, even though most kids need them for at least three more years. Others request that parents provide boosters if their children need them. Still others — including my son’s summer camp — get cranky or downright offended when the topic of booster seats is broached.

When I called the camp with my concerns, the director initially rebuffed me. The vans have complete safety inspections, performed by the California Highway Patrol, she told me. (CHP checks tire size, brakes and other safety requirements, but not seat belt fit.) Drivers go through hours of safety training. Vehicles are outfitted with GPS trackers that send alerts if the driver goes too fast or anything else that might compromise safety.

All of these things are great, but they don’t prevent injury in an accident. The only thing that does is properly fitted safety restraints. After lengthy debate, they reluctantly let me supply a booster for my son, but made sure I knew it was an inconvenience, since different groups of campers use different vans throughout the day.

When I spoke with other parents about the oversight, most didn’t seem too worried. That’s not uncommon, Slattery told me. While people understand the importance of a rear-facing car seat for infants and five-point harnesses for toddlers, boosters often feel like an afterthought. “Parents look at their fragile, itty bitty newborns and want the best protection ever,” Slattery said. “By the time their children are 6, 7 or 8 years old, they just want to be done with car seats, and all of their common sense goes out the window.”

Tara Mello, an automotive journalist based in Huntsville, Ala., saw that fatigue in parents at her daughter’s school who were buckling in kindergartners without a booster. “They’d say, ‘It’s okay, I only live around the block,’ or “It’s okay, I’ve never been in a car accident.” But Mello knows the numbers. Parents are so concerned about their children choking or falling off balconies, she said, but the top cause of death for children younger than 14 is motor vehicle accidents. “If you’re worried about your kids dying, statistically the likelihood is that your kid is going to die in an auto accident.”

Eight years ago, Mello’s daughter was 4 years old when a transit van arrived to take her to an after-school martial arts program in Simi Valley, Calif. When Mello looked inside the van, there were no boosters. The driver assured her it was safe. Mello assured the driver otherwise, then drove her daughter herself and went to speak with the program’s director. He promised that booster seats were forthcoming. For months nothing happened, Mello said, and she finally gave up.

“This was eight years ago,” Mello said. “And while the laws have changed and become more stringent, it doesn’t seem like the programs that are caring for children have kept the pace.”

Change may finally be brewing. Four weeks after my initial conversation with my son’s day camp, I followed up. The director told me that, after looking more deeply into the issue, they had just purchased 150 booster seats for their vans, as had friends of theirs who ran a camp about 100 miles north. And, she said, this will likely be a hotly discussed issue at various camp association meetings this fall. Hopefully, law enforcement and CPSTs like Slattery will be invited to take part in the discussions.

Lauren Gravitz is a journalist in San Diego who covers science, health, and medicine. She tweets @lyrebard.

Want more of On Parenting? Sign up right here for our newsletter:

More reading: