The disaster was man-made due to TEPCO's negligence in planning for predictable contingencies and due to their post-disaster behavior. This is from the Wikipedi

The disaster was man-made due to TEPCO's negligence in planning for predictable contingencies and due to their post-disaster behavior. This is from the Wikipedia article on the Japananese investigation into the disaster: https://en.wikipedia.org/wiki/National_Diet_of_Japan_Fukushima_Nuclear_Accident_Independent_Investigation_Commission#Commission_findings https://en.wikipedia.org/wiki/National_Diet_of_Japan_Fukushi... Here's the main part: The nuclear incident "cannot be regarded as a natural disaster," the NAIIC panel's chairman, Tokyo University professor emeritus Kiyoshi Kurokawa, wrote in the inquiry report. "It was a profoundly man-made disaster -- that could and should have been foreseen and prevented. And its effects could have been mitigated by a more effective human response."[3] "Governments, regulatory authorities and Tokyo Electric Power [TEPCO] lacked a sense of responsibility to protect people's lives and society," the Diet's Fukushima Nuclear Accident Independent Investigation Commission said. "They effectively betrayed the nation's right to be safe from nuclear accidents. Therefore, we conclude that the accident was clearly 'man-made'," it said.[4] The nuclear incident was the result of poor earthquake-safety planning and faulty post-tsunami communication.[10] As a result of collusion between the facility's operator Tokyo Electric Power Co. (TEPCO), regulators and the Japanese government the nuclear crisis at the Fukushima Daiichi power plant unfolded as a "man-made disaster".[6] The report attributed the cause of the failings to Japan's culture of "reflexive obedience", noted that there was no separation between atomic regulation and promotion and described a Japan in which nuclear power became "an unstoppable force, immune to scrutiny by civil society."[6] TEPCO, regulators and the government "failed to correctly develop the most basic safety requirements -- such as assessing the probability of damage, preparing for containing collateral damage from such a disaster, and developing evacuation plans," the NAIIC said. According to the report the lack of training and knowledge of the TEPCO workers at the facility reduced the effectiveness of the response to the situation at a critical time following the quake and tsunami. As the crisis escalated, TEPCO, the regulators, government agencies and the prime minister's office were ineffective in "preventing or limiting the consequential damage" at Fukushima Daiichi.