Originally Posted by dedwards0323

At the heart of the problem is the airbag’s inflator, a metal cartridge loaded with propellant wafers, which in some cases has ignited with explosive force. If the inflator housing ruptures in a crash, metal shards from the airbag can be sprayed throughout the passenger cabin—a potentially disastrous outcome from a supposedly life-saving device.

Nailing down the root cause and determining which of Takata’s several inflator designs is implicated has been tough for Takata, the automakers, and independent investigators to establish. It now appears there are multiple causes, as well as several contributing factors, including poor quality control in manufacture, several years of exposure in high heat and humidity regions, and even the design of the car itself. If the propellant wafers break down, due to high humidity or another cause, the result is that the propellant burns too rapidly, creating excessive pressure in the inflator body.