More than 30 students and teachers at Banteay Chhmar High School in Banteay Meanchey province are recovering after a rash of fainting and vomiting on Saturday.

School director Khlot Samay said on Sunday that the students and teachers began fainting and vomiting after witnessing student Sary Charany, 18, vomit on the school campus.

In total, 35 people either fainted or vomited and were sent to the Thma Puok District Referral Hospital.

“In our school, I haven’t allowed any snacks besides noodle soup, chicken rice and porridge. And the first female student who vomited did not eat food from our school. Thus, medical experts and authorities haven’t ascertained the cause yet,” Samay said.

Thma Puok District Referral Hospital head Nhem Phearum said according to the symptoms of those admitted and interviews with them, the cause was likely food allergies suffered by Charany, whose illness then sparked spontaneous, similar symptoms in others who had not shared her food brought from home.

Another cause under investigation is chemicals sprayed on nearby crop fields.

“Our officials collected the victim’s vomit and sent it to a lab at the Banteay Meanchey Provincial Hospital for tests. We are currently waiting for the results,” Phearum said.

Charany said she became dizzy and vomited after eating food she brought from home that was prepared by her mother for Lunar New Year.

“After eating rice and drinking water, I felt too full and wanted to vomit. My legs and arms turned cold and it was difficult to breathe. I also had a headache and felt dizzy,” she said.

Men Phearen, a teacher at the school who fainted, said he had not eaten before the incident and lost consciousness when he went to the aid of other students impacted by Charany’s illness.

“It was caused by the vomiting, not food poisoning as I hadn’t eaten anything yet that morning,” he said.

Mao Sy, the father of a student who fainted, said he believes a chemical substance could be to blame because his daughter became weak and lost consciousness.

“I don’t know what happened for sure, but my daughter did not have any disease. She felt like vomiting, but nothing came out. So I think it was caused by a chemical substance,” he said.

Thma Puok district governor Diep Chhuon said the weather was stuffy and some villagers near the school used chemical substances to spray their crops to deter insects.

This could have led to students becoming ill, he noted.