Citing “an urgent matter of public safety,” two U.S. senators are pressing the National Highway Traffic Safety Administration to immediately finalize side-impact crash test standards for children’s car seats.

Responding to a ProPublica investigation, Sens. Maria Cantwell, D-Wash., and Tammy Duckworth, D-Ill., members of the Senate Commerce, Science and Transportation Committee, admonished regulators for failing to meet the requirements of two laws.

Nearly 20 years ago, Congress passed a law requiring NHTSA to develop rules to protect children from head injuries in side-impact crashes. The second law was passed in 2012. (The government has a child car seat standard for front-impact crashes.) The agency only proposed a side-impact test for car seats in January 2014 after additional congressional pressure, but NHTSA still hasn’t enacted the testing mandate. Efforts to develop and implement this test have been hampered by industry pushback, limited data on accidents involving children and antiquated testing technology.

The Department of Transportation has projected that it will publish the final side-impact test rule in March. Even if that date sticks, it’s unclear how soon manufacturers will have to start testing their seats. The current proposal would give car seat makers three years from publication of the rule to comply.

“There are real world consequences to this inaction,” the senators wrote in a Feb. 14 letter to NHTSA Acting Administrator James C. Owens. “For example, ProPublica reported the details of potential negligence of a booster seat manufacturer, Evenflo, in developing and marketing its ‘Big Kid’ booster car seat product that may fail to protect children in side impact crashes, which accounted for an estimated 25 percent of vehicle collision fatalities for children under the age of 15 in 2018.”

A ProPublica investigation this month revealed that in the absence of federal side-impact testing rules, booster seat manufacturers are making up their own rules and deciding what passes. Evenflo marketed its top-selling Big Kid booster as “Side Impact Tested” even though the company’s test videos showed child-sized dummies careening out of their shoulder belts in ways Evenflo’s top car seat engineer admitted under oath would put real children at risk of catastrophic injuries or death. Under the rules Evenflo made up, the only way to fail the test was if the dummy wound up on the floor or the seat broke into pieces.

As ProPublica reported, one Evenflo engineer said in a deposition that the company “side-impact test[s] our seats, but I don’t think we say that we offer any type of side-impact protection.”

The senators wrote: “Evenflo also asserts that their products meet the company’s own side impact standards. However, alleged videos of side impact testing calls into question the level of protection these standards provide.”

NHTSA’s proposed side-impact test wouldn’t apply to most booster seat models currently being sold. The testing requirement only applies to seats for children under 40 pounds. NHTSA suggested manufacturers can avoid side-impact testing their booster seats by relabeling those seats as safe only for children 40 pounds and up. If companies take NHTSA’s recommendation and merely relabel their booster seats, that will allow them to continue to make up their own side-impact tests for booster seats and pass themselves.

The senators, who gave Owens a March 4 deadline to reply, asked whether Evenflo had consulted with NHTSA when the company came up with its side impact standards and whether the Big Kid had ever failed any of NHTSA’s tests.

“On what date and in what manner did NHTSA first learn about concerns related to the safety performance of Evenflo booster seats in side impact collisions?” the senators asked.

The senators told Owens that NHTSA “has a responsibility to ensure that every child restraint system product on the market is accurately marketed, and more importantly, adequately protects children in side impact collisions.”

“What actions has, or will, NHTSA take in coordination with the Federal Trade Commission and the Consumer Product Safety Commission to crack down on false and deceptive advertising by makers of child safety seats and booster seats?” they asked.

NHTSA did not respond to ProPublica’s questions about the Senate inquiry.

Since ProPublica published its investigation, five class-action lawsuits have been filed against Evenflo alleging the car seat maker deceived its customers and violated various state consumer protection laws. All of the complaints in these suits cite ProPublica’s reporting.

“As a consequence of its cynical profiteering, Evenflo has now subjected millions of children to the risk of grave injury and death,” stated one of the complaints, filed in federal court in Massachusetts. “Had Evenflo disclosed the results of its side-impact testing to the public,” the complaint said, “no parent or guardian would have purchased a Big Kid booster seat.”

Evenflo General Counsel Amy Blankenship said in a written statement to ProPublica that her company was aware of the senators’ letter to NHTSA. She declined to address the letter or the class-action suits specifically but said generally that Evenflo’s 800 employees “care deeply about child safety” and trust the company’s products “enough to use them with our own children.”

“Evenflo is dedicated to providing safe and effective products for children and families, any claims to the contrary are false,” Blankenship wrote. “We are in the business of safety and for the last 100 years have provided parents with some of the most effective, cutting-edge and rigorously tested safety technology.”

Evenflo also faces an investigation by the U.S. House Committee on Oversight and Reform’s Subcommittee on Economic and Consumer Policy. On Feb. 12, Rep. Raja Krishnamoorthi, D-Ill., and Rep. Katie Porter, D-Calif., gave Evenflo’s CEO until Feb. 24 to provide the company’s testing, labeling and other records related to its marketing of the Big Kid and other boosters.