Takata Corp.'s record U.S. recall of potentially deadly air bag inflators could take years to complete, industry experts and safety advocates said, as automakers scrambled to line up replacement parts, some not from Takata.

After doubling its recall of defective air bags to nearly 34 million vehicles, the Japanese company and competitors scrambled to ramp up production of replacement parts.

The complexity of the recall could play out over at least two years, said Kevin Pollack, vice president for Stericycle ExpertSolutions, which is helping some of the affected automakers. "There weren't 30 million extra air bag inflators sitting around."