Experiment using liquid nitrogen at 4 elementary schools in Kochi; 33 children suffered from mild frostbite. The experiment involved spreading liquid nitrogen on the floor of a gymnasium and observing how it evaporates.
Kochi City's Environment Director Koji Takaoka commented, ``We sincerely apologize to the children and their guardians.We will take even greater measures to ensure safety to prevent incidents like this from happening in the future.'' The patient complained of pain and skin pain. Three of these people visited medical institutions, and their symptoms were said to be mild.