On September 12, 2009, Usui's family reported him missing from his hometown of Kasukabe when Usui did not return from hiking in nearby Gunma Prefecture.

2009年9月11日，臼井仪人前往群马县附近爬山，从此失去联系。9月12日，其家人向警方报案。

youdao

The company's factory in Kasukabe, Saitama prefecture, on the outskirts of Tokyo is about 120 miles from the Fukushima Daiichi plant.

WSJ: Radioactive Traces Found in Japan Baby Formula