Is an auto-safety system reliant on manufacturers' recalls no more trustworthy, say, than an aging Takata air bag in a hot, humid climate?

That's how it looks to advocates like Clarence Ditlow, director of the Center for Auto Safety. Ironically, thanks to the failures of the system he criticizes, you may not realize just how perilous Takata air bags can be - even if you have one in your car.

As many as 30 million U.S. vehicles may be equipped with air bags whose deteriorating inflators could blow apart and send shards flying like shrapnel. But since Tokyo-based Takata says the risk is linked to hot, humid climates, fewer than 1 in 3 have been recalled.

To Ditlow, this is a flashing red light signaling an old problem: a safety system still broken 14 years after Congress supposedly fixed it with 2000's TREAD Act - passed after a furor over injuries and deaths blamed on Firestone tires with separating tread, many on Ford Explorer SUVs.

As with those tires and the rollover crashes they triggered, it took years for regulators to wake up to more recent hazards, such as faulty ignition switches that can turn GM cars into death traps if a key ring weighs too much.

Each delay likely leads to more injury and death. Yet the National Highway Traffic Safety Administration, charged with shepherding defect probes, at best seems underfinanced and overmatched by the auto industry. Ditlow sees a deeper issue, too. With a revolving door linking NHTSA to the industry, he says, it's become a classic "captive regulator," loyal more to the firms it oversees than to the customers it is supposed to protect.

"Obviously, Congress didn't get it right," Ditlow told me while outlining the failures of TREAD - the Transportation Recall Enhancement, Accountability and Documentation Act.

For instance, the law requires automakers to report each death and injury that might be tied to a defective part. But instead of requiring documentation that could speed investigations, NHTSA accepts vague summaries.

"They have a category of 'air bag,' and now 60 percent of death and injury reports say 'air bag,' " Ditlow says. That can include air bags that fired when they shouldn't or didn't seem to deploy properly. The case of the Takata air bags is completely different: The hazard apparently arises when an inflator's casing rots so much that it flies apart when an air bag, as designed, fires with explosive force.

So far, Takata has confirmed two deaths, and two more are suspected. Three of those four are outside the recall zone. In one, Ditlow says, "investigators thought it was a homicide. They'd never seen such sharp-edged wounds."

One question, which arises in every big defect case, is how many deaths or serious injuries are buried by the civil-justice system. Victims and their families are pushed to sign nondisclosure orders in return for settlements. The money may cover the costs of treatment or ease the pain of a severe injury or family's loss. But the gag order likely means more future victims, because fewer people will hear of the hazard.

How do you know if you're at risk from the Takata defect? It's not easy - one reason about 30 percent of all recall repairs never get done. Last month, NHTSA published a list of 7.8 million vehicles affected - mostly older Hondas, but also from nine other automakers. You can find it at SaferCar.gov or call 888-327-4236.

If you search NHTSA's site by your vehicle's VIN number, the regionally limited recalls mean you may not learn you have a suspect air bag. And if you call a Philadelphia-area dealer, you'll get a response that varies by manufacturer, says one local service manager. Nissan has plenty of parts. Toyota won't have them until New Year's. Honda has some, but it's prioritizing places with persistent heat and humidity.

And if your Accord, say, spent most of its first 10 years at Mom and Dad's Florida retirement condo? Make noise, and ask for an exception. Or follow Toyota's advice: Avoid the front passenger seat until the repair is done.

Could the defect be tied to age rather than just climate, as Ditlow speculates? Could NHTSA do more, and quicker - such as use its power to speed replacement parts from third-party suppliers?

Yes, and yes. But nothing is likely to happen unless the agency gets a stronger directive, and more support, from Congress.

The Obama administration has ordered a review of the "safety culture" at NHTSA. That's a start. But the problem isn't just culture. The problem is a system that allows evidence of a defect to be buried along with its victims.

jgelles@phillynews.com

215-854-2776 @jeffgelles