2014 has been a record-breaking year for auto recalls related to alleged vehicle defects. Among the most recent vehicles being recalled en masse are those containing air bags manufactured by Japanese auto parts manufacturer Takata. These are the air bags with components that can allegedly explode, sending shrapnel into the vehicle and potentially injuring or killing vehicle occupants.
So far, the rupturing air bags have been linked to at least five deaths and injuries in the dozens. And like other recall stories this year, this one keeps getting worse as new details emerge. According to news sources, the use of ammonium nitrate in air bag propellant may have played a central role in the dangerous ruptures. And documents reveal that Takata was concerned about the explosion dangers of this compound as early as 1995. Nonetheless, the company began using ammonium nitrate in its propellant starting in 2001.
In the 1990s, manufacturers of air bags began looking for a compound to replace a widely used one called sodium azide. It was being phased out because it could create toxic fumes. Finding the right propellant was difficult because it had to be able to inflate an airbag in microseconds, it had to be non-toxic and it had to remain stable for the life of the automobile.
Ammonium nitrate apparently meets the first two criteria, but Takata and others have long known that the compound is vulnerable to changes in temperature and high levels of moisture. Considering that Takata air bags find their way into cars sold all over the U.S. and the world, considerations like temperature and moisture stability are difficult ones to overlook. Other major manufacturers of air bags say that they do not use ammonium nitrate in their propellants.
It is unclear exactly how Takata plans to solve a problem affecting tens of millions of vehicles, particularly because it continues to assert that ammonium nitrate-based propellant is safe and stable. What is clear, however, is that this defect is a hazard of epic proportions and will continue to endanger the safety of countless car owners.
Source: The New York Times, “Airbag Compound Has Vexed Takata for Years,” Hiroko Tabuchi, Dec. 9, 2014