Abstract
Formaldehyde concentration in treated water in some water treatment plants along the Tone River exceeded the Drinking Water Quality Standard in Japan in May 2012. Water supply was halted in five cities and approximately 870 thousand people were affected by this accident in Tokyo metropolitan area. It was finally proved that, over 10 tons of hexamine, a formaldehyde precursor, was transported into a waste treatment factory without an appropriate notice from the emitting chemical company and discharged from the waste treatment factory. It then contaminated the river water, introduced into water treatment facilities, and transformed into formaldehyde by chlorination in water treatment. We hereby describe governmental risk management framework in this situation and show future direction.
