Frustrated by a piecemeal approach of recalling batches of affected vehicles here and there, lawmakers and safety advocates recently pushed for a recall of all cars equipped with shrapnel-shooting Takata airbags. But federal safety regulators say that this sort of all-at-once recall may actually do more harm than good.

A recall of all vehicles with Takata airbags would simply strain the replacement part production process too much and would only create more uncertainty for consumers about whether or not their cars are safe to drive.

That was the message that National Highway Traffic Safety Administration chief Mark Rosekind tried to get across in a letter to senators who had urged the complete recall of Takata airbag-equipped vehicles, The New York Times reports.

“A blanket recall of all inflators would be easier to explain, but it would not serve safety and could run the risk of exceeding NHTSA’s statutory authority,” Rosekind wrote.

Rosekind says the agency’s current approach, which has thus far led to the recall of 24 million vehicles from 14 automakers, is adequate and ensures that the highest risk vehicles — generally those that are older — are fixed first.

“Both field and test ruptures have been limited to older vehicles,” Rosekind wrote, noting that the current recall list “ensures that the oldest, and therefore highest-risk, inflators are addressed soonest.”

The problem, safety advocates and lawmakers say, is that the piecemeal recalls have left millions of potentially unsafe vehicles on the roads.

Rosekind countered that assertion, saying in his letter that even if all the vehicles were recalled there simply aren’t enough replacement parts available to fix the issue.

About 74% of the replacement inflators for recalled cars are made by suppliers other than Takata, but for the remainder there are no readily available non-Takata replacements, he said in the letter.

“For some vehicles the only remedy currently available is a newer version of the same part, which may also degrade over time and need to be replaced again,” Rosekind wrote, mentioning the recent discovery of the root causes for the airbags’ explosions.

Last week, a group of scientists announced that three factors — the use of propellant ammonium nitrate, manufacturing issues, and prolonged exposure to humidity work together to cause the airbag ruptures, that have been linked to nine deaths in the U.S., 10 worldwide, and hundreds of injuries.

Florida Senator Bill Nelson, who urged NHTSA to initiate a complete recall of vehicles with the Japanese parts maker’s airbags, tells the Times he’s not convinced the agency is doing all it can.

“I remain troubled by the fact that NHTSA still seems to be deferring to Takata on a number of important issues,” he said in a statement. “If there’s one thing we have learned from our investigation, it’s that Takata can’t be trusted.”

Auto Safety Agency Resists Broader Recall of Takata Airbags [The New York Times]

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