NHTSA demands info about Takata's airbag propellant

WASHINGTON -- The National Highway Traffic Safety Administration has demanded that Takata produce documents and answer questions under oath about its use of ammonium nitrate as a propellant in its airbag inflators, according to documents posted on NHTSA’s website Wednesday.

The added scrutiny on Takata’s use of the compound suggests that regulators may be looking at ammonium nitrate as a possible root cause of ruptured Takata inflators, which have been linked to five deaths worldwide and have prompted millions of recalls.

The demands were detailed in a Nov. 18 special order from the agency, which is equivalent to a subpoena. It carries a maximum $35 million fine if TK Holdings, the U.S.-affiliate of Japanese airbag maker Takata Corp., fails to comply by the Friday deadline.

For more than a decade, Takata has used ammonium nitrate as the gas-producing propellant to inflate airbags in a fraction of a second following a crash. It’s an inexpensive chemical used in explosives and fertilizers that can become unstable when exposed to humidity and moisture.

According to the special order, NHTSA wants all documents that express or hint at concerns that ammonium nitrate is too unstable to use in airbag inflators, or that there are other problems with the compound.

The agency wants Takata to produce a timeline detailing every instance since January 2000 that the chemical composition of its inflator propellant was changed, what changes were made and the reasons for those changes, as well as details about all Takata personnel involved in those changes.

NHTSA also wants Takata to turn over any studies or testing data about its airbag inflator propellant formulas.

The special order is part of NHTSA’s investigation into Takata airbag inflators that have prompted the recall of more than 10 million vehicles in the United States. Despite months of work looking into the problem, Takata, NHTSA and automakers have yet to identify the underlying cause of the airbag ruptures.

During a House subcommittee hearing earlier Wednesday, Hiroshi Shimizu, senior vice president of global quality assurance at Takata, said the company still has not identified the root cause behind the ruptures but said the age of the inflators and prolonged exposure to highly humid climates are contributing factors.

Takata has acknowledged that the replacement inflators it is producing now for recalled vehicles use ammonium nitrate. But Shimizu has said the inflators are safe because of changes in the compression of the propellant tablets and certain manufacturing changes.

NHTSA wants internal Takata documents cited in a Reuters report that the newswire said indicated that Takata supplied millions more vehicles with the ammonium nitrate compound than had been previously known.