Various components of a Takata air bag from a Honda automobile are seen before the start of a Senate hearing on Nov. 20. (Gary Cameron/Reuters)

Honda said Wednesday that it will expand its recall of cars with potentially deadly air bags to all 50 states, a decision that could result in the recall of several million vehicles.

Honda made the move one day after Takata, the Japanese auto supply company that makes the air bags, refused to comply with a federal demand that it expand the recall beyond several Southern states.

If Takata had agreed to the recall order by the National Highway Traffic Safety Administration, all of the automakers who install the company’s air bags would have been bound to carry it out.

Honda Executive Vice President Rick Schostek announced the recall expansion at a hearing before a House subcommittee that heard testimony from two other automakers — Toyota and BMW — a Takata vice president and NHTSA Deputy Director David J. Friedman.

In the face of sharp criticism from committee members, Takata’s Hiroshi Shimizu was unrelenting in insisting that the recall be limited to regions of the country with persistent high heat and humidity.

Although conceding that the company has not found what causes the air bags to malfunction, spraying drivers and passengers with metal shards, Shimizu argued that the deaths and injuries it has investigated occurred in humid regions, primarily Florida and Puerto Rico.

“The data indicates that we should remain focused on areas of high temperature and humidity,” Shimizu said.

The response of Rep. Billy Long (R-Mo.) typified the skepticism Shimizu faced from the committee.

“How many people would need to die before you would do a nationwide recall?” Long said. “It’s tantamount to driving down the road with a shotgun aimed at your chest.”

When a vehicle is involved in a collision, sensors ignite a solid wafer of chemical propellant inside the metal canister of the air-bag inflator. A chemical reaction creates a gas that inflates the air bag within milliseconds, popping it from the steering wheel or dashboard.

But if the propellant burns faster than intended, it produces more gas than the vents into the air bag can handle. The metal canister can break into fragments that spray the driver or passengers.

At least five people have died and scores have been injured by Takata air bag malfunctions.

“If our products are defective, supported by the scientific data, we are responsible,” Shimizu said.

At least 7.8 million older-model cars equipped with Takata air bags have been subject to recalls that have been underway for several years. The recalls involve 10 automakers— Toyota, Honda, Mazda, Mitsubishi, General Motors, Subaru, Ford, Chrysler, BMW and Nissan.

Takata produces 1 in 5 air bags worldwide.

Given that neither Takata nor auto manufacturers have been able to pinpoint the cause of the malfunctions, Rep. John Sarbanes (D-Md.) questioned the quality of air bags being installed in the recalled vehicles.

“If you don’t know the root cause, how do you know that the replacement part that you’re supplying solves the problem?” Sarbanes said.

Shimizu, who contends the problem is a manufacturing flaw rather than an engineering defect, said he was confident that replacement air bags supplied by the company are safe.

At one point, Rep. Henry A. Waxman (D-Calif.) said Shimizu’s responses were “nonsensical” and “confusing to drivers.”

Several committee members also challenged the three automaker representatives at the hearing with a similar question: Would you allow a family member to drive a car with a Takata air bag?

All three said that if a vehicle had been recalled, they would suggest that it immediately be taken in for a replacement air bag.

“If they don’t feel safe, we will tow the vehicle,” Toyota Vice President Abbas Saadat said.

That gave rise to questions about whether replacement air bags could be produced fast enough to meet the needs of the recall. Shimizu said the company is producing 300,000 air bags a year and would expand production to 450,000 units when new facilities come on line in January. He also said the company is working with two other suppliers to address the demand.

“What does a driver do [with] a vehicle that’s in a recall that’s not going to be repaired for a year, year and a half?” Rep. Joe Barton (R-Tex.) asked.

Friedman told the committee that NHTSA would continue to take steps to force Takata to announce a nationwide recall, while working with automakers to ensure that they independently recall cars with Takata air bags.

After the hearing, Friedman was asked if the replacement Takata air bags and those that automakers are installing in new vehicles are safer than the recalled models. He said the problem appears to develop several years into a vehicle’s life, so new air bags are likely to be safer.

But will they have problems in five to 10 years?

“You’re asking the exact same question we are,” Friedman said.

To see a video, go to washingtonpost.com/posttv/business .