The Wall Street Journal is reporting that the Japanese government is continuing to show its long-standing concern over reports of first-generation iPod nano’s overheating, and eventually catching fire.

The ministry is requesting Apple Japan to explain the cause of overheating, whether similar incidents have been reported domestically and abroad and what prevention and cautionary measures have been taken to counter such incidents, according to Seiji Shimagami, a ministry official who works in consumer product safety.

The order came following an incident in Tokyo that took place on July 13, when sparks flew from a user’s device while it was recharging, according to Masahiro Yamazaki, the head of the consumer product safety unit at METI.

According to the report, the Japanese government responsible for overseeing this issue has documented 27 instances of first-generation iPod nano’s overheating while charging, identifying those instances as “fire-related.” Six of those 27 instances have been documented since a warning in 2008 about the overheating was issued.

“iPods are incredibly well designed and safety is the highest priority for Apple. We are taking METI’s letter in regard to the first generation iPod nano very seriously and are working closely with them to answer their concerns,” Apple said in a statement.

If you own a first-generation iPod nano, you are encouraged to bring it into your local Apple Store and have it checked for any damage.