Japanese trade and economy ministry announced that they are currently investigating iPod's hardware quality after one of the popular digital music players "shot out sparks" while recharging.
A Japanese official revealed that they suspect the problem to be related to the lithium-ion battery in the iPod Nano, model number MA099J/A.
The problem surfaced in January in Kanagawa Prefecture southwest of Tokyo, and Apple reported the problem to the ministry in March.
Around 425,000 units of this model has been shipped to Japan since it was released in September 2005 through September 2006 when it was discontinued. The number of units sold to Japanese customers is still unknown as well as the number of units shipped outside Japan.