While details are limited on the incident, Donald Johnson, a professional engineer who deals with stray voltage and electrocution investigations, said that many factors could be at play in this particular incident.
"There are a lot of things that could have caused this. Many seem unlikely, but you never know -- electricity can do strange things," Johnson told ABC News. He suggested that it could be something that was specifically faulty with the charger being used.
When asked if others should be worried about this, he said, "I wouldn't be concerned about it at all. The investigation will be important, but usually low-voltage items, like a phone charger, aren't a concern."
There have also been recent reports of safety issues with the iPhone's closest competitor -- the Samsung Galaxy S. Last week a Swiss teenager said she had suffered third-degree burns after a Samsung Galaxy S3 exploded in her pocket. Samsung has also promised to investigate.
Apple has recently begun a major push into the Chinese market. In April Tim Cook apologized to Chinese consumers for what he said were misunderstandings about Apple's repair and warranty policy in the country. In 2011, China became Apple's second-largest market, behind the U.S.