Teacher Poisons Students
This picture taken on Jan. 17, 2018 shows a female student in a classroom at Beihang University in Beijing. Wang Zhao/AFP/Getty Images

A kindergarten teacher in China has been arrested under suspicion of poisoning 23 students.

The students were reported to have their porridge poisoned with sodium nitrite, which is typically used to prevent the growth of bacteria but can be toxic in high amounts for animals and humans.

After eating their breakfast last Wednesday, the students began vomiting and fainting, state media reported. At least one child had to have their stomach pumped and several others are still being treated at the hospital. The incident was not reported by police until this week.

The students received medical attention at a local hospital, while the school was temporarily shut down. One child is reportedly seriously ill.

It is unclear why the teacher deliberately poisoned the children.

This is the second tragedy to kindergarteners in recent months. In October, a woman attacked at least 14 kindergarteners with a kitchen knife.