Investigators have identified toxic additives in snack foods as the source of lead contamination affecting dozens of children and staff at a kindergarten in northwest China’s Gansu Province, with preliminary laboratory tests confirming excessive pollutants in steamed date cakes and corn sausage rolls served to both children and teachers.

The findings emerged during a July 3 government briefing where officials disclosed that two preserved food samples from Heshi Peixin Kindergarten in Maiji District, Tianshui City, showed abnormal additive levels, according to audio recordings and parent accounts, ThePaper reported on Sunday.

So far, it's unknown what the toxic additives are.

The crisis expanded as teachers revealed they consumed identical meals and experienced symptoms, including dizziness and nausea, weeks before the scandal broke.

All students and staff members have undergone blood tests, though results remain unknown. Some have conducted follow-up examinations in hospitals in Xi'an in neighboring Shaanxi Province.

Alarming discrepancies in blood test results have fueled public outrage. Multiple children initially cleared by local health authorities — with readings under 20μg/L, China’s safety threshold for minors — showed severe lead poisoning when retested in Xi’an, 500km away.

Medical evidence reveals catastrophic exposure levels among students. Physicians at Xi’an Central Hospital confirmed to Shangyou News on July 3 that multiple children from Heshi Peixin Kindergarten — all presenting with severe lead poisoning — required emergency treatment, with blood lead concentrations ranging from 300 to over 400μg/L.

These readings, 15-20 times China’s safety threshold for minors, indicate potential organ damage requiring intensive chelation therapy. Hospital records show that all affected children originated from the same Maiji District kindergarten.

Opened in 2022, the kindergarten enrolls about 200 children and charges 6,000 yuan (US$837) monthly for tuition.

Kindergarten owner Li Huifang faces criminal investigation.