By Colleen Kave, J.D.
The National Highway Traffic Safety Administration recently published several documents pertaining to its ongoing investigation into the causes of Takata (TK Holdings Inc.) airbag inflator ruptures. The primary document, Takata’s own report on its internal investigation into the root cause of PSAN (phase-stabilized ammonium nitrate) airbag inflator ruptures, was compiled pursuant to the Consent Order entered into by Takata and NHTSA in November 2015. The other three documents present research summaries pertaining to the root cause of the inflator ruptures, one provided by Takata, and the other two by independent entities.
Takata’s Report of Internal Investigation. Included in the internal investigation report is a chronology of Takata’s actions, beginning with the development and manufacture of its airbag inflators and spanning its investigations of reported ruptures, the various recalls of affected vehicles, and its efforts to mitigate the impact of its product failures. According to the report, the company began to develop PSAN inflators in the late 1990s and early 2000s because it believed the use of PSAN was less toxic, safer to manufacture, and more gas efficient than other propellants, thus allowing for smaller, lighter inflators that were more easily integrated into smaller, more fuel-efficient vehicles and vehicle interior designs while providing increased manufacturing and occupant safety. However, Takata immediately encountered difficulties with the inflators, including failures to meet certain process validation specifications prescribed by vehicle manufacturers and ruptures of inflators. The company admits that the final versions of process validation test reports omitted these test failures or included substituted or altered results. The report also reveals that Takata knew of an incident involving a driver inflator rupture in Switzerland as early as 2003, and that it learned of a second rupture in 2005, but the two incidents were dismissed as anomalies based on the limited information available for their review.
When incidents involving inflator ruptures began to increase in 2007, Takata began an intensive investigation, and the report details the progression of those studies, the involvement of NHTSA, vehicle manufacturers, and independent experts, and the ongoing, extensive safety recalls affecting millions of vehicles. The report also discloses the contents of the original Consent Order, under which Takata agreed to pay a $70 million civil penalty, the amendments thereto, and the terms of NHTSA’s Coordinated Remedy Program, pursuant to which vehicles will receive replacement inflators according to a prioritized schedule. Finally, the remedial steps already implemented by Takata are delineated, including NHTSA’s appointment of an Independent Monitor to oversee Takata’s safety and compliance programs and other obligations under the Consent Orders; the establishment of a safety hotline and a website for Takata employees to communicate with the Independent Monitor; the appointment of a Chief Safety Assurance and Accountability Officer and the creation of a Safety Accountability and Assurance Office; the evaluation by an independent auditing firm of Takata’s data vault; the establishment of a Product Safety Group and an Early Warning System to notify manufacturing plants about potential risks in order to enable them to take appropriate action; and the development of an independent Quality Assurance Panel to review and assess Takata’s current policies, practices, procedures, structure, and personnel.
Other research summaries. NHTSA also released three research summaries related to the Takata airbag inflator investigation. The Takata (Fraunhofer ITC) Research Summary, entitled Technical Report on the Current Status of the Takata Root Cause Evaluation Effort (July 22, 2016), lays out Takata’s current understanding of the cause of the inflator field ruptures involving PSAN propellant as of the spring of 2016, and it attributes the root cause of propellant degradation to moisture exposure with long-term thermal cycling as a necessary element. The report states that the degradation takes nearly a decade to reveal itself, and it occurs primarily in climates characterized by a persistent high absolute humidity.
The second document, the Exponent Research Summary, similarly concludes that ruptures of the Takata airbag inflators occurred due to physical degradation of the propellant in the form of "larger internal pores/channels/voids (‘pores’)." The report explains that the degradation arises from diurnal and seasonal temperature cycling, and is exacerbated by higher peak cycle temperatures and increased total moisture in the inflator. The temperature fluctuations of the inflator result in moisture exchange between the propellant and the surrounding headspace, ultimately resulting in "the development of porosity."
Finally, the Orbital ATK Research Summary determines that three factors adversely affect certain inflators made by Takata: the presence of PSAN propellant without moisture-absorbing desiccant; long-term exposure to repeated high-temperature cycling in the presence of moisture; and an inflator assembly that does not adequately prevent moisture intrusion under conditions of high humidity.
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