The infrastructure ministry said Friday that emergency inspections on sewage pipes, which were conducted in the wake of last month's road cave-in in Yashio, Saitama Prefecture, have found abnormalities such as corrosion at three locations in the same prefecture, separate from the incident site.
The prefecture has begun taking countermeasures.
The sewage inspections were carried out as a deteriorated sewage pipe is believed to have caused the road cave-in in Yashio.
The three locations where abnormalities were found were pipes leading to a sewage treatment plant in Wako in the prefecture. There was corrosion at two locations inside manholes in Kawagoe and a misaligned pipe joint in a manhole in Fujimi. No cavities under roads caused by sewage pipe problems were confirmed.
On Feb. 21, the ministry will hold the first meeting of an expert panel on measures to prevent a recurrence of the cave-in incident. The panel is expected to discuss which pipelines should be subject to regular inspections and how often they should be inspected.
"We will firmly implement the necessary measures to ensure the safety and security of the people," infrastructure minister Hiromasa Nakano said during a news conference Friday.
January's incident occurred at a large pipeline that collects sewage water from 12 municipalities in Saitama and leads to a sewage treatment plant. The emergency checks covered a total of approximately 420 kilometers of similar large sewage pipelines in seven prefectures, with inspections carried out inside about 1,700 manholes on those pipelines.
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