In August 2009, after ruptured air bag inflators in Honda vehicles were linked to least four injuries and a death, the automaker quietly requested a design change and did not notify U.S. regulators, Honda confirmed in response to inquiries from Reuters.

Honda Motor Co. asked supplier Takata Corp. to produce a "fail-safe" air bag inflator, according to Takata presentations and internal memos.

The previously undisclosed redesign could make Honda and Takata more vulnerable in more than 100 pending federal lawsuits and dozens more state suits, according to several legal experts and an attorney suing the companies.