I had to track down the original story for this, but here's the link to it:
It's in Chinese, so I can't read it without help of the Google Translator. This is a google-translated excerpt (with my own grammatical fixes) of the news article:
Xiaogang felt pain after the accident, and immediately called to tell his
father about his injury. Emergency personnel said they rushed to the
scene. When they arrived, Xiaogang could still speak, and he was immediately rushed to hospital
for treatment, where he eventually died of excessive bleeding.
It is reported that in just one month the Jiaozhou Central Hospital
admitted three other patients suffering from similar pneumatic rotary chair explosions.
Although their injuries were also to the buttocks, no objects became
lodged in the body, and they only suffered minor injuries.
There is another news report of a woman whose chair also exploded, along with descriptions to four other incidences involving exploding chairs, one of them about the young lad who died in the above story:
- On 20th April, 2007, in Dinghai district, Zhoushan town of Zhejiang province, the chair on which Ms. Lou was sitting exploded; plastic
pieces, timber splinters, and metal washers pieced her body to a depth
of 100mm deep.
- On 26th November 2007, a 68 years old man was badly injured in similar circumstances.
- On 26th March 2008, the chair in front of Mr Lin's computer suddenly exploded while Lin was beside it. Mr. Lin's back and arms
were injured and an 150mm long steel rod was ejected and hit the
- On 14th January 2009, in Jiaozuo, Shandong province, a 14 year old boy was killed by his exploding
chair. Doctors told the media that similar explosions had happened on
3 occasions in that month.
So yes, these chairs' pneumatic mechanism can explode, and yes it's possible to die from it. No, there are no significant statistics available, particularly for outside of China. However, from what I have tracked down, there have been at least 8 incidents.