Revelations Moa Point wastewater plant's collapse could have been avoided if Wellington Council had gone ahead with a second stage of construction.
An independent Crown review of the February disaster, which let billions of litres of raw sewage flow into coastal waters, found three decades of governance and risk assessment failures.
Report author Raveen Jaduram says it's likely councillors didn't know they needed to build the next stage.
"Because of the time delay, people leave and the new people coming in didn't know and didn't make it their business to find out."
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