By Maki Shiraki, Paul Lienert and Ben Klayman
TOKYO/DETROIT (Reuters) - Takata Corp (7312.T) has modified the composition of an air bag propellant that contains a volatile chemical at the center of a recall of millions of cars worldwide, the company told Reuters.
A Takata official, who did not want to be named but spoke on behalf of the company, did not specify how the recipe has changed, but said ammonium nitrate remained a part of the mix. He told Reuters the shift was part of its process of 'kaizen', or continual improvement, and the company believed the new composition was safer than the one used before.
In response to a question, the official said:
"There is no admission of a defect with the original version. There has not been any finding that ammonium nitrate or the earlier composition was somehow flawed. We changed the composition in an effort to improve quality."
The official said the company used the modified mix in replacement bags fitted in cars brought in during the recalls, but declined to say exactly when the change was made or in which models, and how many vehicles' air bags with the new propellant have been installed.
The official also declined to comment on whether the new mix was cheaper than the previous one. "There have been no problems with the new versions so far," he said.
Takata has said the original version of the compound, when exposed to moisture or improperly processed, can cause the inflators to explode with excessive force, spraying metal shards inside the car. Its air bags, used by many leading car makers, have been linked to at least four deaths in the United States and are the focus of a U.S. regulatory probe and multiple global recalls in the past six years.
Since 2000, Takata has made more than 100 million inflators according to industry estimates and company data. Starting in 2008, more than 17 million cars equipped with its air bags have been recalled, including more than 11 million in the United States.
While Takata has been using ammonium nitrate, an inexpensive chemical commonly found in fertilizer and explosives, rivals Autoliv (ALV.N) and TRW Automotive (TRW.N) use less volatile guanidine nitrate as the main ingredient, people close to the companies have said.
Takata made the disclosure about its reformulated propellant after Reuters had sought its comment about a Reuters analysis of internal Takata documents. The analysis found the company supplied millions more cars than previously known with air bags that used ammonium nitrate-based propellant and were made at its plant in Monclova, Mexico.
Carmakers are not required to disclose their suppliers, but the Reuters analysis and senior employee profiles showed Takata provided air bags for some of Detroit's best-selling models that have not been subject to recalls. There is no evidence of any air bag-related incidents with any of those vehicles.
The Takata official declined to comment on the analysis.
Asked if it had reports of such incidents among vehicles not included in existing recalls, the U.S. National Highway Traffic Safety Administration said: "There is no evidence that all Takata air bags produced over the past 15 years pose a current danger to the driving public, and it would be inaccurate to make such a claim."
"There is evidence, however, that certain Takata air bags inadvertently exposed to excessive moisture during manufacturing or regions with consistently high temperatures and humidity pose a safety risk," the safety regulator added.
A 2012 Takata employee roster from Monclova shows a number of workers made air bag inflators for several Ford (F.N) vehicles. And online profiles of three senior employees mentioned their involvement in the development of several popular Ford, GM (GM.N) and Chrysler (FCHA.MI) models.
Available data puts the total production of those models at up to 6.6 million cars, though it's not clear whether all were equipped with Takata air bags.
None of the big three carmakers would confirm that Takata air bags were installed in models that have not been subject to recalls or indicate any problems.
"We have no field data indicating a problem with Takata air bags in our vehicles," said GM spokesman Alan Adler. "We are continuing to monitor the situation and will put our customers' safety ahead of all else. But we will not engage in what-if scenarios."
Ford spokeswoman Kelli Felker said Takata was focused on testing those Ford vehicles that are part of a regional recall requested in June by regulators, and would not discuss other models.
A Chrysler spokesman said the automaker has used inflators from multiple sources and with varying designs, and none have caused any problems. "All benefit from robust manufacturing processes and are subject to rigorous daily testing. None has exhibited the failure modes that have prompted current investigations."
(Additional reporting by Joanna Zuckerman Bernstein in Mexico City; Editing by Tomasz Janowski and Ian Geoghegan)