Experts test the self-heating hot pot.
The Shanghai Consumer Council warned on Tuesday that people using the popular new product, self-heating hot pot, could be burned or injured in the explosion.
The hot pot contains hot buns, which are activated when water is added-and then the ingredients are steamed.
City council officials say these products are popular because of their convenience.
According to the committee, during the annual Double Eleven shopping spree in November last year, sales of self-heating hot pots reached 4.53 million, more than double the 1.7 million in 2017.
However, there is no industry standard and there are security issues.
The committee tested 20 self-heating hot pot products purchased online and offline, with prices ranging from 16.9 yuan (2.5 U.S. dollars) to 49.9 yuan. The test covers the temperature, the exhaust gas after activation and the contents of the thermal bag.
Shang Zhaocong, deputy director of the National Chemical Product Safety and Quality Supervision and Inspection Center, said: "The test found that the heat pack emits a combustible gas such as hydrogen, and the amount of hydrogen is very large."
According to Shang said, a pack of hot pot can produce about 40 liters of hydrogen.
"Eating hot pot in a closed space, such as a car or a room with closed windows, can be dangerous," Shang said.
"If people start a car or smoke after eating two packs of food, there is a risk of explosion, because the 4% hydrogen concentration in the space will cause combustion."
Shang said that the test also found that one of the hot pots reached a maximum temperature of 121.9 degrees Celsius, which poses a risk of burns.
In addition, the packaging of the six samples was deformed during use.
The committee recommended that the relevant authorities draft a standard covering safety requirements and product warnings.
The committee warned consumers that they should avoid using hot pot in enclosed areas and classify it as hazardous waste.
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