TOKYO (AP) — A prominent volcanologist disputed Japanese regulators’ conclusion that two nuclear reactors were safe from a volcanic eruption in the next few decades, saying Friday that such a prediction was impossible.

A cauldron eruption at one of several volcanos surrounding the Sendai nuclear power plant in southern Japan could not only hit the reactors but could cause a nationwide disaster, said Toshitsugu Fujii, University of Tokyo professor emeritus who heads a government-commissioned panel on volcanic eruption prediction.