Overview
- An independent committee led by Fujino Yōzō submitted its final report on February 19, 2026, concluding the sinkhole originated with sewer-pipe corrosion caused by hydrogen sulfide.
- The panel found the collapse likely began when corrosion opened gaps in the pipe, creating a void above it, with the hole forming directly over the sewer and no other draw-in factors identified.
- A 2022 floating-camera inspection covered about 600 meters, but spray and low light prevented clear imaging of the ultimately damaged section, and roughly 52–71 meters showed signs consistent with corrosion or damage.
- The report says a more cautious evaluation of the 2022 findings could have inferred heightened risk, yet it stops short of saying the sinkhole could have been predicted or reasonably prevented.
- Recommendations include reviewing inspection methods, re-inspecting segments where images were not obtained, recording sections as unevaluable when necessary, and developing tools for clearer imaging, while noting no practical technique exists to detect voids around buried pipes.