Apparently the problem is with the front passenger sport seat that, over time, develops cracks in its covering. An air bag sensor beneath the area can then be damaged so that the car no longer senses the weight of a passenger. That means, of course, the passenger airbag might not be deployed in an accident.
BMW is doing the right thing by quickly addressing the issue even though no accidents or incidents have been reported in relation to the problem. Also, according to NHTSA, the company will extend the warranties of several of BMW models to cover the issue for 10 years with no mileage restriction. A summary of the recall No. 08V384000 is available here from NHTSA.
[Source: Associated Press via CNN]