A group of 18 attorneys general is criticizing the National Highway Traffic Safety Administration for failing to mandate tests for children’s car seats that mimic the forces in side-impact crashes, despite a law more than two decades ago requiring the agency to protect kids in such collisions.

“The failure to promulgate side-impact testing standards unnecessarily endangers children on the road and does a huge disservice to families,” the attorneys general representing 17 states and the District of Columbia wrote in a letter on Tuesday to Transportation Secretary Pete Buttigieg, whose office oversees NHTSA.

The letter adds to the pressure Congress has applied to NHTSA since a ProPublica investigation last year exposed how Evenflo, one of the largest child seat manufacturers, marketed its bestselling Big Kid booster as “Side Impact Tested” even though the company’s own tests demonstrated that children in those seats could be paralyzed or killed in such crashes.

In an interview, Connecticut Attorney General William Tong, the co-leader of the group, described ProPublica’s story as “thorough, extensive and horrifying” and signaled that the letter may not be the last step for the group. The 18 attorneys general who signed the letter, Tong said, are taking a “very hard look” at local consumer protection laws. Such laws prohibit unfair and deceptive acts and practices.

A NHTSA spokesperson, in an emailed response to questions, said the agency planned to issue its final side-impact performance requirements for children’s car seats by January 2022. But the agency made it clear it planned to exclude booster seats like the Big Kid from those tests when it proposed the new rules in November. A NHTSA spokesperson did not respond when asked if that was still the plan.

Absent a federal testing standard, children’s car seat makers are allowed to continue to design their own tests and decide what constitutes a passing grade. Evenflo’s side-impact tests on its booster seats were so lax, ProPublica found, that the only way to fail was if the child-sized test dummy wound up on the floor or the seat broke into pieces.

In response to ProPublica’s findings, a U.S. House subcommittee last year launched its own investigation, which found widespread evidence that the nation’s largest manufacturers of car seats endangered the lives of millions of children and misled consumers about the safety of booster seats. Indeed, the congressional investigators described the side-impact tests that manufacturers currently perform as “meaningless.”

As a result, the House Committee on Oversight and Reform’s Subcommittee on Economic and Consumer Policy last December asked the National Association of Attorneys General to encourage its members to open investigations into “dangerous practices and unfair and deceptive marketing regarding children’s car seats and booster seats,” pointing to evidence in the congressional investigators’ report.

That prompted the consumer protection chiefs of the 18 attorneys general’s offices to take a closer look. Tong said he was “horrified” to read in ProPublica’s story how Evenflo decided whether its seat passed the side-impact test the company itself had created. After each of the tests, an Evenflo technician would check a “yes” or “no” box on a form that asked whether that test showed “dummy retention.”

In its story, ProPublica included excerpts from a sworn deposition of the Evenflo test technician who filled out those forms as well as photos of the actual tests he reviewed. The deposition was part of a case brought by the family of a Texas girl who was paralyzed in a side-impact crash while seated in a Big Kid booster. The family of that child, who requires a ventilator to breathe, later settled the case with Evenflo.

The test photos showed the body of the child-sized dummy careening grotesquely outside the protection of the seat belt. Had the dummy been a real child, the head could have hit a door or something else in the car. Yet the technician always checked the “yes” in the “dummy retention” box and forwarded the forms to an engineer who decided if the seats got a passing grade. They all passed.

“It’s deeply and personally affecting for those of us who are parents,” said Tong, who is a father of three. “The willful denial of facts and science in pursuit of profits and the idea that they would approve these tests and that they never rejected a test despite this clear evidence that the dummy was not retained in any meaningful way is really scary and puts people at risk.”

Tong added that “the suggestion that they exceed federal standards for side impact — I understand that’s sleight of hand with language. But that kind of thing is unconscionable frankly.”

Tong’s coalition of attorneys general on Tuesday urged Buttigieg and NHTSA’s acting administrator to “save children from avoidable injury,” noting that motor vehicle crashes are the leading cause of death in kids ages 1 to 13.

A federal law passed in 2000 directed NHTSA to enact standards that would protect children in side-impact crashes, but two decades later, those rules still don’t exist. Children’s car seats and boosters only have to pass tests that mimic the forces a child’s body would experience in head-on crashes. Yet side-impact crashes are more likely to result in serious injuries because there’s only a door between the child and an intruding vehicle.

On Twitter this week Tong wrote that “families cannot wait another 20 years for NHTSA to finally act.”

His coalition also urged NHTSA to require labels on children’s car seats that warn parents that their children should remain in their current car seat until they reach the height or weight limits. Children move from rear-facing seats to forward-facing seats with harnesses and then on to booster seats, which rely on the vehicle’s seat belts rather than built-in harnesses. Parents often think of children graduating from one stage to the next, like a milestone to be celebrated. But in fact, each transition reduces the amount of protection a child receives in a crash.

“Encouraged by marketing from child car seat manufacturers, parents and children are understandably excited about moving up to the next seat in the progression,” Tong’s coalition wrote in its letter. “But experts all agree that to best protect child passengers from injury, they should wait and not rush the transition.”

Given this well-established fact, the coalition wrote, “we are concerned by NHTSA’s failure to require this important principle on car seat labels and boxes.”

Evenflo and other manufacturers had long marketed their booster seats for children weighing as little as 30 pounds even though experts agree that children of that weight are best protected in traditional car seats with built-in harnesses. ProPublica’s investigation last year revealed that one of Evenflo’s top car seat engineers in 2012 recommended the company stop marketing its boosters to children less than 40 pounds, arguing they’d be safer in harnessed seats. But a marketing executive vetoed him, an internal Evenflo record shows.

ProPublica also detailed examples of children weighing less than 40 pounds who were gravely injured in side-impact crashes while seated in Big Kid boosters. Jillian Brown, a 10-year-old New York girl, suffered an injury medical journals sometimes call “internal decapitation.” Like the girl in Texas, Jillian is paralyzed from the neck down and must rely on a ventilator to breathe. She steers her motorized wheelchair with her tongue. Jillian, who has always had an independent spirit, cannot clear secretions from her lungs on her own and requires round-the-clock care in the family’s home, which has been transformed to meet her needs. Her family settled the suit it had brought against Evenflo.

Tong said he was struck by the Brown family’s ongoing struggles. “Somewhere in the story, you talk about the older sister who survived the crash and how her younger sister’s care consumes the family, how the parents worry about the older sister and her needs and attention — how profoundly hard that is for their family and for her,” he said. “That was a huge driver for what’s happening now.”

An Evenflo attorney did not answer questions sent by email this week, but last year a different Evenflo attorney told ProPublica that the company kept the weight limit at 30 pounds at that time to accommodate tall, thin children who had outgrown their harnessed seats. The company also told ProPublica that its seats are safe and effective and that it has been a pioneer in side-impact testing. It blamed driver error for the children’s injuries.

Evenflo and its largest competitor, Graco, subsequently raised the minimum weight for their boosters to 40 pounds last year after ProPublica’s story was published and after the congressional subcommittee launched its investigation.

NHTSA last November proposed banning the sale of boosters for children under 40 pounds. In its written statement this week, a NHTSA spokesperson said the agency is working on another rule that “would reduce early transitions to forward-facing car seats and boosters,” but she did not provide any details. That rule, too, would not be done until early 2022, she said.

“We appreciate the interest of the attorneys general in this critical issue and look forward to finalizing these critical child passenger safety regulations,” the NHTSA spokesperson wrote.