The number of vehicles in the U.S. equipped with rupture-prone Takata Corp. air bags being recalled doubled to 34 million, according to a person familiar with the matter, deepening a safety crisis at the Japanese manufacturer that has been tied to six deaths world-wide.

In all, the air bag recalls are expected to register among the largest for a consumer product in U.S. history, eclipsing 31 million bottles of Tylenol capsules recalled after the medicine was linked to cyanide poisonings in the early 1980s. With Takata air bags, at least 10 auto makers have been conducting their own recalls of millions of vehicles apiece to deal with faulty inflaters.

Takata, under pressure from U.S. auto-safety regulators, will declare its air-bag inflaters defective, the person said. Takata has agreed to a nationwide recall of certain types of driver- and passenger-side air bag inflaters, the person said. Regulators have also issued a consent order to Takata that requires the company to cooperate in future government actions related to ongoing probes and oversight of the air-bag supplier, the person said.

The actions, expected to be disclosed by regulators later on Tuesday, expand recalls of 16 million Takata passenger-side air-bag inflaters that are currently limited to regions with high humidity to the entire U.S., the person said. A current nationwide recall of driver-side inflaters is being expanded to 17 million vehicles, the person said.

The age of the inflaters and their geographic location are expected to be considered when prioritizing fixing the vehicles, the person said. Takata has said areas of high humidity are more prone to suffering problems with the air bags.

The Takata inflaters are made with a propellant that can degrade over time, causing air bags to explode and send shrapnel flying in vehicles. Takata and a group of 10 auto makers are separately conducting investigations to determine the root cause of the air-bag ruptures. High humidity and moisture have been linked to the problem.

The air-bag ruptures have sparked widespread lawsuits, a regulatory probe and a Justice Department investigation.

Write to Mike Spector at mike.spector@wsj.com

Access Investor Kit for Takata Corp.

Visit http://www.companyspotlight.com/partner?cp_code=P479&isin=JP3457000002

Subscribe to WSJ: http://online.wsj.com?mod=djnwires