Federal safety regulators are investigating a problem with side air bags that may fail to inflate in a crash.
The problem already has caused recalls of more than 2,700 Toyota, Honda, Subaru and Nissan vehicles, but that number could grow if the National Highway Traffic Safety Administration determines that more automakers used similar defective parts.
The recalled vehicles could have an ineffective mixture of the gas that inflates the side curtain air bags in a crash. That mix could mean air bags on one or both sides of the cars won't inflate, increasing the risk of injury, the agency said in documents posted on its website. So far no one has been hurt.
All four companies with recalled vehicles told NHTSA that the Americas unit of Swedish safety parts maker Autoliv Inc. made the inflators for the air bags. The investigation was opened Feb. 14. Documents detailing the probe were posted on NHTSA's website last weekend.
Autoliv told NHTSA in a letter that it shipped a total of about 10,500 of the problem inflators to automakers and two other air bag manufacturers. In addition to the four companies that have announced recalls, the parts went to Chrysler Group LLC, Ford Motor Co., General Motors Co., Kia Motors America, and Suzuki Motor Corp. The letter did not say which models have the faulty inflators.
Spokesmen for Chrysler, GM and Ford said their air bag inflators are designed differently than other manufacturers and have not failed in extensive testing, so they do not expect any recalls. A message was left for spokesmen at Kia. Suzuki said it could not comment because NHTSA hasn't notified the company about the problem yet.
Autoliv said Tuesday that the problem occurred one time in production parts tests at minus-22 degrees Fahrenheit. But further tests indicated a risk of malfunctions at low temperatures, spokesman Mats Odman wrote in an email.
"We are in a dialogue with our customers and the authorities to ensure that they are fully informed and that the driving public could rely on our products," Odman wrote.
Toyota Motor Corp. and Honda Motor Co. first discovered the problem and reported it to NHTSA on Jan. 31, the documents said.
The recalled vehicles include 427 Toyota RAV-4s from the 2011 model year that were made from Nov. 24, 2011 through Dec. 19, 2011. Also included are 974 Honda Accords, Civics, Crosstours and Acura MDXs from the 2012 model year made between Nov. 30, 2011, to Jan. 26, 2012; 381 2012 Subaru Legacy and Outback cars made from Dec. 1, 2011, through Dec. 23, 2011; and 976 Nissan Altimas and Versa cars from the 2012 model year that were made from Nov. 21, 2011, to Dec. 21, 2011.
AP Auto Writer Bree Fowler in New York contributed to this report.