Japan’s Fukushima nuclear crisis was a preventable disaster resulting from “collusion” among the government, regulators and the plant operator, an expert panel said, wrapping up an inquiry into the worst nuclear accident in 25 years.

JAPANESE nuclear regulators trusted that the reactors at Fukushima Dai-ichi were safe from the worst waves an earthquake could muster based on a single-page memo from the plant operator nearly a decade ago.