At the center of the crisis is a faulty airbag inflator manufactured by Japan's Takata Corporation. The inflator, which used ammonium nitrate as a propellant, was found to degrade over time when exposed to heat and humidity. In some cases, the inflators exploded during deployment, sending metal fragments into the vehicle cabin. The defect has been linked to at least 31 deaths and hundreds of injuries worldwide. More than 100 million vehicles from 19 major automakers—including Honda, Toyota, BMW, Ford, and Nissan—have been recalled since the issue first came to light.