Wang Yun, a Chinese nursery school teacher in China has been sentenced to death for poisoning dozens of children, one of them apparently fatally, in an act of revenge against a colleague.

A court in the central province of Henan said Wang Yun put sodium nitrite into porridge being prepared for her colleague’s students after a falling out with the colleague.

The attack in March last year made 25 children ill. Reports at the time said they began vomiting and fainting after eating their breakfast. One boy was severely ill for months and died in January, according to news reports.

The court said on Monday that Wang knew sodium nitrite was harmful and acted “with no regard for the consequences”.

Her “criminal methods and circumstances were exceedingly bad, with especially severe circumstances, and she should be severely punished in accordance with the law,” the court’s sentencing statement said.

The court said Wang and the manager of the nursery must compensate the children’s families.

It was not the first time Wang had used sodium nitrite to poison someone, authorities said. In 2017 she put some in her husband’s mug, causing minor injuries.

Sodium nitrite is used for curing meats but can be toxic when ingested in high amounts.