PUTIAN, CHINA — A 21-year-old woman in the city of Putian in China's Fujian province died while having hotpot at a Haidilao restaurant, Chinese news outlets reported.

Jiupai News reported last Thursday (Sept 8) that the incident occurred on the evening of Sept 6 at Wanda Plaza in Putian's Chengxiang district. The woman was suspected to have choked on a piece of beef tripe, or cow's stomach lining.

She could not breathe and her entire body was paralysed, the reports said.

The news broke on social media last Thursday, causing the hashtags #女孩海底捞吃火锅意外身亡# (girl suddenly dies while having Haidilao hotpot) and #海底捞回应女顾客就餐时身亡# (Haidilao responds to female customer who died while dining) to trend on Chinese micro-blogging site Weibo.

The posts with the two hashtags on Weibo have more than 300 million views and 420 million views respectively.

In a video that went viral on Weibo, Haidilao's staff members can be seen trying to perform a Heimlich manoeuvre on the young woman. This is a first-aid technique used on choking victims in order to try and force an object out of the windpipe.

A statement from Haidilao said that in addition to providing first aid, the service crew on the scene had also dialled the emergency number 120 for medical assistance.

Unfortunately, they were unable to save her.

The restaurant chain then temporarily closed its Wanda Plaza branch and has begun compensation negotiations with the family of the deceased. It is set to reopen after the two parties reach an agreement.

As the case drew keen attention on Weibo, one online user came forward claiming to be a colleague of the deceased, saying that the woman had been dining with her boyfriend at the time.

This colleague added that the accident occurred because the woman had just eaten beef tripe and was taking a drink of water — when she began to choke.

Tripe can be very tough to eat, and even when cooked thoroughly can still be quite chewy.

Though the cause of death has not been officially determined, this revelation sparked speculations among social media users who said that the tripe might have been too old or under-cooked, making it too difficult to chew.

Other patrons of hotpot restaurants said that they have had similar difficulty with chewing tripe and duck intestine when they are too tough.

Some people also speculated on other possible causes of death, even though they had no evidence beyond the material posted online.

Weibo user "Wertiuii3" felt that another possibility could be angina bullosa haemorrhagica (ABH), or oral blood blisters.

This refers to "the sudden formation of blood-filled blisters in the oral cavity" in the absence of any known systemic disorder.

In this case, Wertiuii3 said, a blood blister could have formed on the roof of the woman's mouth.

A 1987 clinical study on ABH notes that although it is a benign condition, it can "in rare cases result in acute airway obstruction".

Another Weibo user said food that is "too spicy (red oil hotpot), too hot (hotpot base) or too hard" can irritate the throat, resulting in blood blisters that can swell and block the airway in a very short period of time.

The cause of death is still under investigation.

Haidilao said in its statement that it is "deeply saddened" by the incident, and is "actively providing necessary assistance to the family members (of the deceased), fully cooperating with them and the police to investigate the cause (of death), and will assume full legal responsibility".

Haidilao was founded in China's Sichuan province in 1994 and has since expanded its business across many countries around the world, including Indonesia, Japan, Malaysia, Singapore and the United States.