According to the Detroit Free Press, the incident occurred on April 7 when an unnamed owner of a 2012 Hyundai Elantra was in a crash. Apparently the side curtain airbag on the driver's side rapidly inflated (like it's supposed to) but took with it a metal bracket (which it's not). The result was a severe laceration to the driver's ear in an automotive reenactment of Holyfield-Tyson II.
The National Highway Traffic Safety Administration is apparently looking into the event, but has yet to issue a recall. Hyundai for its part insists the incident was isolated, and that it has not received reports of anything similar happening to any other drivers.