A routine school day turned into a dangerous emergency yesterday when a self-heating hotpot malfunctioned at St. Paul’s Co-educational College, sending a dozen students to the hospital with burns and blast-related injuries. The incident, which occurred around 3 PM on May 13, has reignited concerns over the safety of these increasingly popular “lazy hotpot” meals, particularly among young consumers who may overlook critical handling steps.
According to police reports, a male student was preparing the meal when the heating pack likely failed to vent properly, causing a violent pressure buildup. The container burst, spraying scalding liquid across the classroom. The student suffered severe burns on his chest, arms, and thighs. A female classmate nearby also sustained eye irritation from the splashing contents. Both were rushed to Queen Mary Hospital for treatment.
The explosion’s deafening sound caused tinnitus—a ringing in the ears—in eight other students, five boys and three girls, who were all sent to Ruttonjee Hospital for medical checks. The incident underscores a growing safety blind spot around a product marketed for its convenience.
What Makes a Self-Heating Hotpot So Dangerous?
The core of the risk lies in the small heating pack inside each meal. These packs contain a mix of highly reactive chemicals, including quicklime, aluminum powder, iron powder, coke powder, activated carbon, salt, diatomaceous earth, and sodium carbonate. When water is added, an exothermic reaction begins within seconds, generating temperatures above 90°C and releasing large volumes of steam. If that steam cannot escape—because the vent is blocked or the pack is damaged—pressure builds rapidly until the container ruptures. The result is not unlike a small bomb.
Chinese fire departments have conducted controlled experiments to illustrate the hazards. In one test, investigators sealed the steam vent on a hotpot lid with tape. Within minutes, the internal pressure blew the top off with explosive force. In another test, they placed loose powder from a damaged heating pack into a sealed plastic bottle filled with water. The bottle swelled and then detonated, spraying boiling water across the room—a vivid demonstration of how even minor leaks can turn deadly.
Safety Tips for Self-Heating Meals
Proper handling is the only safeguard against these risks. Food safety experts and fire authorities urge users to follow these seven essential guidelines:
- Inspect the heating pack: Before use, check for any tears, leaks, or loose powder. A damaged pack should never be used.
- Keep the vent clear: The lid’s steam hole must be unobstructed to allow pressure to release safely. Never cover it with tape or other materials.
- Avoid glass surfaces: Place the hotpot on a sturdy, heat-resistant mat. Glass tabletops can shatter from uneven heat distribution.
- Use only cold water: Adding hot water can trigger an immediate, violent boil, increasing the risk of scalding.
- Do not microwave or oven-heat: These appliances are not designed for self-heating packs and can cause severe damage or fire.
- Open with caution: After heating, the container and steam remain extremely hot. Keep your face and hands away when lifting the lid.
- Never fly with them: Because they contain flammable chemicals, self-heating packs are classified as dangerous goods and banned from both carry-on and checked luggage.
A Wake-Up Call for Young Consumers
Self-heating hotpots have surged in popularity among students and young professionals in Hong Kong, prized for their quick, no-cook convenience. But this incident reveals a dangerous gap in public awareness. The chemistry inside those small pouches is real and unforgiving. A moment of carelessness—a blocked vent, a damaged pack, or hot water added by mistake—can turn a meal into a missile.
Authorities have not yet confirmed whether disciplinary action will follow at the school, but the broader message is clear: convenience must never come at the cost of safety. For anyone who enjoys these products, learning the proper procedure is not a suggestion—it’s a necessity. And for parents and educators, this incident serves as a powerful reminder to talk to young people about the hidden risks in everyday items.