Railway police officers have called for more attention to self-heating food due to recent safety concerns over its use on trains during the 40-day Spring Festival travel rush, also known as chunyun.

On a slow train from Xiamen, Fujian province to Beijing on Feb 13, a passenger using self-heating food packaging for the first time put self-heating rice into a plastic bag and fastened the bag after she saw vapor leaving the packaging during the process. The plastic bag inflated and almost exploded, according to the Xiamen railway police.

On Jan 28, a passenger surnamed Yin triggered the smoke alarm on the high-speed train G1684 from Xiamen, Fujian province to Kunming, Yunnan province. The train attendant found that as Yin heated rice, she poured quicklime into a plastic box and added water, which produced a large amount of smoke and triggered the alarm.

Self-heating food packaging usually uses a heat releasing reaction between quicklime and water, which could produce 100 C vapor in a very short time and easily burn passengers or their neighbors. If passengers lack experience in self-heating food, they should try to avoid it on the train, the police said.