At least 57 students were poisoned by an unidentified substance in a rural secondary school in the southern Mexican state of Chiapas, according to local authorities. The mass poisoning on Friday was the third at Chiapas schools reported in local media over the past two weeks, spooking students and prompting outrage from parents. 

The Mexican Social Security Institute said Friday that 57 teenage students in the rural community of Bochil had arrived at a local hospital with symptoms of poisoning. One student in a “delicate” condition was transferred to a hospital in the state’s capital while the rest were stable, the institute said. Local news outlets said some parents believe the students were exposed to contaminated water or food.