House panel sets hearing on Takata recalls

“If you don't find out the root cause, who knows? We may have this same discussion again in four, five, six, seven, 10 years,” said David Kelly, a former acting NHTSA administrator now charged with leading a consortium of 10 auto makers investigating the Takata inflators.

Mr. Kelly did not say how soon his group would finish its work. “It is apparent to us that we have a lot of work in front of us,” he said.

New airbags are ‘safe'

“We are confident that our new airbags are safe,” Takata said in a statement May 26, adding that it is conducting “a comprehensive review to ensure Takata's current manufacturing procedures meet best practices.”

The Japanese supplier has been investigating airbag problems for more than seven years, but said it has narrowed the search only to “preliminary conclusions” linked to multiple factors.

Takata has said inflators exposed over several years to high humidity combined with cycling between extreme high and low temperatures are at risk. Too much moisture can cause the ammonium nitrate in the airbag propellant to break down, increasing the risks of a violent explosion, chemical experts and analysts have said.

The company cited other factors, including the design of the inflator or the airbag, which may be prone to leaky tape seals in some cases; the shape of the explosive propellant used to deploy the airbag, and vehicle design. In past recalls, Takata has blamed manufacturing mistakes and problems with proper storage of propellant.

“It's a confluence of a whole series of issues that have been going on for a long time,” said Sean Kane, president of Safety Research & Strategies Inc., a consultant with plaintiffs' attorneys, government organizations and companies.

Propellant under microscope

Takata said it has reviewed more than 45,000 inflators over the past year in ballistic tests, live dissections, propellant analysis for moisture, chemical analysis, air and helium leak tests and CT scans.

Meanwhile, auto makers that used Takata airbag hardware have stepped up efforts to determine the cause of the explosions. Honda Motor Co., which built the vehicles involved in all six of the fatalities attributed to Takata airbags, last autumn bought used and scrapped cars in Japan to conduct its own tests. Two senior Honda insiders said then that the testing indicated shortcomings in Takata's manufacturing quality.

Federal safety regulators recently hired Columbus, Ohio-based research group Battelle Memorial Institute to probe for the cause — a task made more complex because auto makers used four different types of inflators across a wide range of models.

“We have a lot of work to do, especially with regard to why this happened in the first place,” U.S. Transportation Secretary Anthony Foxx said last week.

NHTSA head Mark Rosekind said last week replacement inflators “are safer. The concern is, are they safe over the long term? That has yet to be determined.”

The explosive propellant Takata still uses to power its inflators — ammonium nitrate — is not in the clear, said officials familiar with the various probes. The material is less expensive and cleaner burning than other options, but it can be highly volatile, according to industry officials and chemists.

To make the propellant mix safer, Takata more recently has added desiccant, a material that gathers up and holds moisture chemically and should extend the lifetime of the inflator by two to three times, said a person familiar with the change.

_____________________________________________

Reporter Ryan Beene and Reuters contributed to this report, which appeared on the website of Automotive News, a Detroit-based sister publication of Tire Business.