Alexander Brangman finds comfort in remembering how long his daughter lived — 26 years, 11 months, 9 hours and 15 minutes — rather than the horrible and needless way she died.

Jewel Brangman, an academic all-American in high school, about to pursue a PhD at Stanford, had no need to know much about the rental car she drove north toward Los Angeles on a sunny September Sunday almost four years ago.

Then came a relatively minor crash — she rear-ended a minivan — and her air bag exploded with a spray of razor-sharp metal shards that severed her carotid artery.

Ten years after the biggest safety recall in U.S. history began, Honda says there are more than 60,000 vehicles on the nation’s roads equipped with what experts have called a “ticking time bomb” — defective air bags like the one that killed Brangman. The air bags, which sit about a foot from a driver’s chest, have a 50-50 chance of exploding in a fender bender.

They are the most deadly air bags remaining in the recall involving more than 37 million vehicles built by 19 automakers. At least 22 people worldwide have been killed and hundreds more permanently disfigured when the air bags that deployed to protect them instead exploded and sprayed shrapnel.

The worst among the bad bags are known as Alphas, driver-side air bags installed in Hondas that have up to a 50 percent chance they will explode on impact. The 62,307 people still driving with them, many in older-model cars that may have changed hands several times, either have ignored the recall warnings or never received them, Honda said.

With the number of deaths and disfigurements continuing to climb — the last fatality was in January — automakers and federal regulators have rewritten the rule book in their outreach efforts, including deploying teams to knock on doors of Honda owners who have not responded to recall notices.

“We’re good at repairing vehicles,” said Rick Schostek, executive vice president of Honda North America, “but finding and convincing customers of older model vehicles to complete recalls, now that has proved a difficult challenge.”

The 2001 Honda Civic that Brangman was driving came from Sunset Car Rentals, a small agency that had bought the vehicle at auction almost three years earlier, after it had been involved in a crash and was issued a salvage title. Though it had been under recall since 2009, Honda said it had mailed four recall notices without getting any response.

Brangman’s crash was the epitome of a fender bender: She struck a minivan from behind, damaging its bumper and that of the car she was driving, and buckling the hood of her car.

“There was minimal damage,” her father said. “It was highly questionable if the air bag should have deployed at all. It was something Jewel should have walked away from.”

Instead, “I walked in the USC trauma unit and what I saw was horrific: Here’s the beautiful, angelic human being that was my daughter hooked up to this monstrous life support system,” Brangman said.

The doctors told him she was brain dead.

Brangman later learned that for three weeks his daughter had been driving a rental car with a factory-equipped air bag that during the recall would come to be known as the Alpha model. A quirk in the manufacturing process caused the Alpha inflaters to be the most deadly of the lot.

The massive recall of air bag inflaters made by Takata — which allegedly suppressed tests revealing the flaw and where three key executives are under federal indictment — is well known to Congress and millions of Americans who have been touched by it. But tens of thousands of drivers most at risk remain oblivious to the efforts of automakers and the National Highway Traffic Safety Administration.

“Our last hearing on the ongoing Takata fiasco is just further evidence that NHTSA is just rudderless,” said Sen. Bill Nelson (Fla.), ranking Democrat on the Committee on Commerce, Science and Transportation. “The latest data the committee has received from the automakers shows that individual automaker recall completion rates are all over the place — and millions are still waiting for replacement air bags.”

NHTSA has been without an administrator in the 15 months since Donald Trump entered the White House. The president recently proposed elevating acting director Heidi King to lead the agency. King, whose nomination will require Senate confirmation, told the Commerce Committee last month that car companies have “made progress” on the Takata recall.

“But the progress is uneven,” she said. “Overall completion rates are not where we want them to be.”

Takata air-bag inflaters degrade over time as they are exposed to humidity and repeated wide fluctuation in the daily temperature. That a car may change hands three or four times during a 10-year period has made the recall more difficult, with notices from the car dealer or automaker discarded by people who sold the vehicle years earlier.

While most Takata inflaters go bad over time when exposed to temperature changes and humidity, the Alpha inflaters experienced high humidity at a Takata factory in Monclova, Mexico, before they were installed.

In a 2015 response to Congress marked “confidential,” Takata acknowledged that the propellant that triggers the air bags had “been left in work stations during a prolonged shutdown of the assembly line, exposing them to humidity inside the plant.”

The Alpha bags were installed in more than 1 million Honda and Acura cars between 2001 and 2003. They caused 11 of the 15 U.S. fatalities when their Takata inflaters ruptured.

Although there had been inklings that Takata air bags could be deadly — with fatal explosions in 2003 and 2004 — the first U.S. recall was initiated by Honda in 2008.

The 10 years that followed have been replete with allegations that Takata cut corners in a rush to fill orders and that the company sought to cover up tests that revealed the severity of the problem.

The genesis of the massive recall came when Takata, then a seat-belt supplier but a minor player in the air-bag industry, came up with a cost-cutting way to make air bags. Just a few years after the 1995 Oklahoma City bombing, they used the same material that caused that explosion — ammonium nitrate — to trigger the air-bag inflaters when vehicles collide.

Ammonium nitrate — unlike the relatively stable chemical tetrazole used by other manufacturers — can become unstable, particularly when it is exposed to moisture.

Takata found a ready market for its cheaper air bags, expanding rapidly to meet the demand of newly enticed automakers, including General Motors.

GM’s air-bag supplier had been the Swedish company Autoliv, but Autoliv dropped out of the competition presented by Takata because it declined to use the volatile ammonium nitrate.

Autoliv’s decision to abandon the GM contract was first reported by the New York Times, as was the scenario that ultimately led to the charges filled against three Takata executives.

After a 2002 Honda Accord air bag exploded in Alabama in 2004, Takata assured Honda that the incident was an anomaly. But at the same time Takata began testing 50 air-bag inflaters it had collected from junkyards. Even though two of them malfunctioned, Takata shut down the testing and told technicians to wipe the data from their computers, the New York Times reported. The company denied to Congress that it had ever done the testing.

Years later, NHTSA said Takata was not “being forthcoming with information” or cooperating with the “investigation of a potentially serious safety defect.”

The Justice Department fined Takata $1 billion for that failure.

“Takata has admitted to a scheme to defraud its customers by manipulating test data regarding the performance of its air-bag inflaters,” Barbara McQuade, U.S. attorney for the Eastern District of Michigan, said in announcing the fine last year. “They falsified and manipulated data because they wanted to make profits.”

McQuade also unsealed indictments against three Takata executives who were charged with manipulating test data to deceive the automakers they supplied about the safety of their air bags. The indictment said the three had known as early as 2000 that their air bags could explode.

All three of the men indicted — Shinichi Tanaka, 59; Hideo Nakajima, 65; and Tsuneo Chikaraishi, 61 — are Japanese citizens and have not been extradited to the United States. Faced with spiraling debts estimated at more than $9 billion as a result of the air-bag scandal, Takata declared bankruptcy last year.

Under a consent order signed by Takata and NHTSA, John D. Buretta, a former Justice Department prosecutor, was named to prod the recall process. Buretta’s report last November described the Alpha bag as a grenade that could devastate a car — and its occupants — as if a bomb had exploded inside it.

“There has been, I’m glad to say, marked improvement,” he told the Senate Commerce Committee last month. “There is still much room for improvement . . . and much work to be done.”

Alexander Brangman flew to Washington last month for the committee hearing.

“Jewel was the eighth victim at the time; now worldwide there’s 22,” Brangman said afterward. “Not prohibiting ammonium nitrate being used in these bags is sinful. Unethical behavior is the underlying theme. For a life to be taken when something is preventable is unconscionable to me. They should find a way to stop using these vehicles, period.”