Toyota Motor Corp., Fiat Chrysler Automobiles NV, Volkswagen AG and Mitsubishi Motors Corp. are still selling new vehicles with defective air bags that will eventually need to be recalled, according to a report by a U.S. lawmaker overseeing the agency handling the largest-ever auto safety recall.

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 air bags.

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.