Safety regulators in the U.S. are investigating air bags in certain Hyundai and Kia vehicles that failed to deploy in frontal collisions linked to four deaths and six injuries.
As many as 425,000 automobiles made by the South Korean manufacturers may be affected, according to an investigative report posted on the U.S. National Highway Traffic Safety Administration's website. NHTSA is investigating whether vehicles made by other carmakers may also be at risk.
The crashes involve Hyundai Sonatas and Sonata hybrids made in 2011, and Kia Forte and Kia Forte Koups made in 2012 and 2013. Hyundai on Feb. 27 recalled almost 155,000 Sonatas after determining that an electrical overstress failed to inflate the air bags during collisions. Hyundai is looking into the product supplier, ZF-TRW, for a possible cause for the electrical problem.