By Kim Smiley
Air bags are designed to save lives and there is no doubt that they do, but they can also be deadly if they malfunction. At least 5 deaths and many more injuries since 2004 have been tied to metal fragments that burst out of faulty air bags.
A Cause Map, or visual root cause analysis, can be used to analyze the problem with some air bags manufactured by Takata, one of the largest air bag companies in the world. A Cause Map visually lays out the causes that contributed to a problem to show the cause-and-effect relationship between them. A Cause Map is built by asking “why” questions. So why are people being injured and even killed by air bags?
The air bags in question have a metal canister inside them that contains a solid wafer of chemical propellant. Once the propellant is ignited, a chemical reaction occurs that very quickly creates gas that is used to inflate an air bag. The problems happen when the wafer of propellant burns too quickly and the pressure from the gas over-pressurizes the metal canister. If the canisters burst, metal fragments are shot into the vehicle where they can hit passengers.
One of the more interesting (and alarming) things about this issue is that nobody seems to know exactly why the chemical propellant is burning too quickly. The problem appears to be related to humidity and vehicles in highly humid regions seem to be at higher risk, but not all experts agree with this assessment. Takata has admitted to production issues at a plant in Washington state and says that the some of the chemicals used in the air bags were left out and exposed to humidity causing them to react too quickly, but there hasn’t been evidence released that directly ties these manufacturing issues to the defective air bags. There is concern that the design itself may be the problem and that it’s a much larger issue than a manufacturing defect impacting a relatively small number of air bags.
The handling of the issue has also been problematic. There is evidence that both Honda and Takata knew about a death possibly tied to air bags as early as 2004, but decided it was an anomaly. Some believe that the companies were slow to react as more deaths and injuries associated with malfunctioning air bags occurred. 7.8 million vehicles with Takata air bags have been recalled, most of them in humid regions. Takata has been resistant to expanding the recall of the air bags beyond high humidity regions and has been threatened with fines by federal regulators.
The bottom line is that it’s difficult to know how to handle a problem when you don’t know exactly what the problem is. As Representative John Sarbanes said “If you don’t know the root cause, how do you know that the replacement part that you’re supplying solves the problem?” Some automakers, such as Honda, have made deals with alternative air-bag suppliers for substitute parts to use during the recall because of the unresolved issues with the Takata air bags. The recall process will likely take some time because the spike in demand for new air bags is going to severely tax manufacturers available to supply them.
To see a high level Cause Map of this issue, click on “Download PDF” above. You can also click here to see what vehicles have been recalled so far.