The students were among a group of 77 from Sakai Municipal Mikunigaoka Junior High School on a field trip to tour a factory. Just after noon, someone from Yakult Honsha Co. Kyoto factory in Uji called for an ambulance, the Mainichi Daily News reported.

Doctors at a local hospital said the students were hyperventilating. They reportedly had been exchanging ghost stories on the bus to the factory, working themselves up into a state of acute fear.