A Japanese parliamentary panel has concluded that the incident at Fukushima nuclear plant was "a profoundly man-made disaster".
In its report, the panel stated that the disaster "could and should have been foreseen and prevented" and its effects "mitigated by a more effective human response", it said.
Both Tepco and the Japanese government were found to be culpable of serious deficiencies in their response, reports the BBC.
The panel referring to the disaster as "Made in Japan", because the mindset that allowed the accident to happen can be found across the country.
It flagged up the bureaucracy's role in both promoting and regulating the nuclear industry, and also cultural factors such as a traditional reluctance to question authority.
In the panel's final report, its chairman said a multitude of errors and wilful negligence had left the plant unprepared for the earthquake and tsunami.
It said that the situation at the plant worsened in the aftermath of the earthquake because government agencies "did not function correctly", with key roles left ambiguous.
The report said regulators should "go through an essential transformation process" to ensure nuclear safety in Japan.
"Japan's regulators need to shed the insular attitude of ignoring international safety standards and transform themselves into a globally trusted entity," it said.
The report was made from the findings of the Fukushima Nuclear Accident Independent Investigation Commission, which was set up to examine the handling of the crisis and make recommendations.
The investigation included 900 hours of hearings and interviews with more than 1,000 people.
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