Automakers confirmed they are continuing to sell some vehicles with ammonium-nitrate inflators without a chemical drying agent, and cited engineering and supply challenges to explain why they are still relying on the faulty airbags.

The vehicles are legal to sell but must be recalled by 2018. Legal experts said that based on previous cases, it was unclear if there could be additional legal liability for selling vehicles subject to future recalls, though if anything goes wrong with those vehicles, they could be subject to product-liability lawsuits.

The automakers and Takata have been hit with class-action lawsuits from owners, and Takata is the subject of a Justice Department criminal investigation.

The report by the top Democrat on the committee that oversees the U.S. National Highway Traffic Safety Administration (NHTSA) is the latest to raise concerns about the massive recall of close to 70 million U.S. air bag inflators and nearly 100 million worldwide.

“This may be the first time in history where multiple automakers are selling brand new cars with a known, and potentially deadly, defect,” said Karl Brauer, senior analyst at Kelley Blue Book.

Takata inflators can explode with excessive force and spray metal shrapnel. They are suspected in 13 deaths worldwide and more than 100 injuries. There are no deaths or injuries reported in Takata inflators with a drying agent, NHTSA said.

It was not clear precisely how many new cars are being sold with defective inflators. The affected vehicles include the 2016-2017 Mitsubishi i-MiEV, 2016 Volkswagen CC, 2016 Audi TT and 2017 Audi R8.

NHTSA said there have been no ruptures in any vehicles built since 2008, suggesting the vehicles won’t be prone to danger for six years or more.

“There just aren’t enough non-defective replacement airbags to go around,” said Rich Newsome, an Orlando lawyer representing people who have sued Takata. “It’s kind of like the ticking time bomb, and everyone’s betting the bomb won’t go off for six years.”

According to NHTSA, the vehicles don’t become vulnerable to exploding airbags without long-term exposure to high humidity. In the short-term, the agency says, they are safe to drive – and much safer than the older models.

NHTSA said it needs to prioritize replacing the oldest inflators in high-humidity areas. NHTSA has taken control of the massive recall from individual automakers, using its legal authority to do so for the first time.

“What’s troubling here is that consumers are buying new cars not realizing they’re going to be recalled,” U.S. Senator Bill Nelson, a Florida Democrat and the report’s author, said in a statement. “These cars shouldn’t be sold until they’re fixed.”

NHTSA did not directly respond to Nelson, but said it agrees more should be done to speed up recall completions. There is no required public disclosure by automakers or car dealers that vehicles include parts that will need to be recalled.

Takata inflators do not pose unreasonable risk when installed in a new vehicle or for several years afterward, NHTSA Administrator Mark Rosekind said last month. That gives automakers the legal footing to continue to sell the vehicles.

Takata spokesman Jared Levy said in a statement the company is “working aggressively” and has produced more than 15 million replacement kits.

MORE RECALLS EXPECTED

Ford Motor Co announced Wednesday it is expanding its Takata air bag recalls by nearly 1.9 million vehicles – and more recalls are expected Thursday.

Last month, Takata agreed to declare as defective another 35 million to 40 million U.S. inflators that lack drying agents in frontal airbags. Eight automakers announced recalls of more than 12 million vehicles as a result.

Previously, automakers recalled inflators in 24 million vehicles.

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Wednesday’s report also said more than 2.1 million ammonium-nitrate replacement inflators without drying agents have been installed in U.S. vehicles as of March – and will eventually need to be replaced.

Fiat Chrysler told the committee at least one of its current models contains a frontal passenger-side airbag that uses the ammonium-nitrate inflators without a desiccant or drying agent. It said Wednesday that no vehicle being sold is under recall and it is moving on an accelerated timetable.

Honda Motor Co, which has recalled 10.2 million vehicles in the United States for Takata inflators including some more than once, told the committee that 17,000 new vehicles are equipped with inflators without drying agents, but no additional new vehicles will be equipped with such inflators.

Toyota, one of two automakers that did not provide specific models to Senate investigators, expects to produce approximately 175,000 vehicles with the defective Takata inflators by July 2017, the report said.