"Seventy to 80 percent of the ruptures" involve air bags that were used in vehicles from Florida, he added.
But while the problem of defective airbags initially appeared to center around problems at Takata, NHTSA recently received word of faulty deployments involving older vehicles using inflators produced by the supplier ARC Automotive Inc. A formal investigation covering 500,000 Chrysler Town & Country minivans and Kia Optima sedans, which used air bag systems with ARC inflators, was announced earlier this month.
At the time, Knoxville, Tennessee-based ARC issued a statement saying it has a 60-year record of "serving our customers with products that meet the most stringent global safety standards." It also said it is cooperating with the NHTSA probe.
ARC did not respond to requests from The Detroit Bureau for comment about the possibility of a broader issue with the inflators.
So far, just two "incidents" have been identified involving ARC inflators, but the concern is that there may have been others that have not been identified, said Clarence Ditlow, director of the Washington-based nonprofit Center for Auto Safety.
"Could we have missed more? That could be the case," said Ditlow, noting that several Takata air bag deaths were initially misidentified. In one case, he noted, Florida police initially thought the shrapnel wounds to a victim's head and chest were the result of a vicious knife assault and began looking at the crash as a murder scene.
So far, Takata appears to be an outlier. Investigators are attempting to determine if the serious problems with its products were the result of design of its air bag inflators, with the material used to make those explosive devices or the manufacturing process itself.
But the emerging concern, which could have much-broader safety implications, is whether even good inflators could go bad over time.
Read MoreDrivers hit the road again in 2015
Air bag systems typically are exposed to big variations in temperature - in some cases from minus-40 to over 200 degrees Fahrenheit - and humidity. And they are shaken and rattled by railroad tracks, gravel roads and potholes.
Complicating the situation, the age of the average vehicle on the road today is 11 years, the oldest ever. That means some vehicles with the very earliest air bag systems are still in operation.
"It may be a reasonable assumption that as these things age they deteriorate," said automotive analyst George Peterson.
Even a small amount of pyrotechnic material flaking off, or changing in molecular structure could significantly alter the way they inflate when triggered, experts suggest. Meanwhile, over time, "Seals (could) start breaking down," said NHTSA's Rosekind, which could allow explosive gases to do unintended things.
While Takata remains the primary focus of the NHTSA air bag investigation, Dave Zuchowski, the CEO of Hyundai Motor America, told TheDetroitBureau.com that his company was advised by an agency official of "the potential residual (problem) of older vehicles with original air bags."
"It appears there is more to the air bag story than just Takata," Zuchowski added, noting that the Korean carmaker is now checking its records to see if it has used any of the ARC inflators (because Hyundai and Kia often share technology and suppliers) or experienced other air bag issues that might have been missed previously.
In the more than a quarter century since the first supplemental restraint mandate went into effect, air bag systems have become increasingly sophisticated. Some vehicles today feature more than 10 of the devices to protect passengers not only in frontal crashes but in side impacts and rollovers. Even critics of how the technology has been implemented acknowledge that air bags have saved thousands of lives.
"No one is saying you should disable your air bags," safety advocate Ditlow stressed. "You're far more likely to be helped than hurt by one if they go off."