Claims made by students in Jilin province, who said they were poisoned after being exposed to toxic substances at their school, were called into question on Tuesday when the local government released what it said was proof the school was free of toxins.

The government in Da'an city released a statement on Monday saying an indoor environmental test conducted by a professional company on Sunday proved the student dormitory at Xin'anli Township Junior High School was safe.

The move followed a claim by 15 students that they had been poisoned after living and studying at the facility since October.