The 35‑year‑old mother, traveling with her husband and their one‑year‑old daughter, reported throat irritation but no serious injuries. Other passengers in the same carriage also noticed a strange odor, though authorities could not confirm whether any substance had been released.
Firefighters inspected the train after it stopped at Kawasaki Station in Kanagawa Prefecture but detected no harmful gases.
The train had departed Odawara in Kanagawa Prefecture and was bound for Takasaki in Gunma Prefecture. The incident was reported around 4:30 p.m. while the train was between Yokohama and Kawasaki stations, according to railway operator JR East.
Earlier, it was reported that a nuclear power plant in Japan’s central Fukui Prefecture temporarily shut down one of its reactors on Friday morning after a steam leak had been detected near a high-pressure turbine.