TOKYO — The nuclear accident at Fukushima was a preventable disaster rooted in government-industry collusion and the worst conformist conventions of Japanese culture, a parliamentary inquiry concluded Thursday.

The report, released by the Fukushima Nuclear Accident Independent Investigation Commission, challenged some of the main story lines that the government and the operator of the Fukushima Daiichi Nuclear Power Plant have put forward. Most notably, the report said the plant’s crucial cooling systems might have been damaged in the earthquake on March 11, 2011, not only in the ensuing tsunami. That possibility raises doubts about the safety of all the quake-prone country’s nuclear plants just as they begin to restart after a pause ordered in the wake of the Fukushima crisis.

“It was a profoundly man-made disaster — that could and should have been foreseen and prevented,” said Kiyoshi Kurokawa, the commission’s chairman, in the report’s introduction. “And its effects could have been mitigated by a more effective human response.”

While assigning widespread blame, the report avoids calling for the censure of specific executives or officials. Some citizens’ groups have demanded that executives of the plant’s operator, the Tokyo Electric Power Company, or Tepco, be investigated on charges of criminal negligence, a move that Dr. Kurokawa said Thursday was out of his panel’s purview. But criminal prosecution “is a matter for others to pursue,” he said at a news conference after the report’s release.