In 1998, Takata began using a new airbag propellant (based on a compound called tetrazole) that was supposed to represent a big leap forward in reliable airbag inflation for automotive parts company. However, in 2001, Takata switched to ammonium nitrate and began distributing the airbags to car manufacturers. The new compound is very sensitive to moisture and has a tendency to explode in warm climates after it breaks down over time. According to Paul Worsey, an expert in explosives engineering at the Missouri University of Science and Technology, the compound shouldn’t be used in airbags and is more suitable for large demolitions in mining and construction. “But it’s cheap, unbelievably cheap” he said.
Now, this compound is the center of a huge safety crisis: 14 million vehicles with Takata-made airbags have been recalled worldwide. At least five deaths have also been linked to the faulty airbags. Alby Berman, a spokesperson for Takata, stated that cost was not the main motivation of the compound change, instead it was the claim that ammonium nitrate produced gas more efficiently and with less emissions. Engineers at Takata stated that, initially, there were concerns about the safety issues that may come with the switch. Ammonium nitrate is unstable because it can change from one phase to another due to varying temperatures during the day and at night. So, using the compound was said to be prone to damage. Katsumi Kato, an assistant professor in safety engineering at Japan’s Fukuoka University, said,
Speaking generally, ammonium nitrate can be unstable. Its crystal structure can change according to temperature… It changes the burn rate. It leads to various malfunctions.”
Other automakers have stayed away from this compound. Instead, Key Safety Systems for example (another airbag manufacturer), uses guanidine nitrate and tetrazole. Takata’s aim was to keep ammonium nitrate stabilized, however, there are limits on how long the compound can be stabilized. Takata stated that the company continues to use ammonium nitrate in their airbags which should be safe to use in areas with relatively low levels of humidity.
Takata is currently facing a Senate hearing and numerous legal challenges. The company is now preparing for a criminal investigation.
Read more here – “Takata’s Switch to Cheaper Airbag Propellant Is at Center of Crisis,” (Hiroko Tabuchi, New York Times).
Anna is a current student at The George Washington University in Washington, DC with a concentration in Marketing and Communication. She specializes in social media outreach and has experience working in government contracting.