The science ministry provided data on the radioactive fallout to U.S. forces a few days after the crisis erupted at the Fukushima No. 1 nuclear plant — far earlier than the public was informed, a ministry official said.
The revelation came amid criticism that the government’s delay in releasing data from the System for Prediction of Environmental Emergency Dose Information (SPEEDI) may have resulted in the unnecessary exposure of residents near the plant to radiation. Those residents were later evacuated.
The data were provided to the U.S. forces via the Foreign Ministry on March 14, three days after the 9-magnitude temblor and monster tsunami triggered the triple-meltdown crisis, according to Itaru Watanabe, an official with the ministry’s Science and Technology Policy Bureau.
But it was not until March 23 that the public was officially told.
Watanabe, speaking Monday at a meeting of the nuclear accident investigation panel set up by the Diet, said the science ministry passed on the data to the U.S. forces “to seek support from them” in dealing with the nuclear crisis.
After the crisis at the Fukushima plant began, the government could not use SPEEDI as originally anticipated because data on the amount of radioactive substances released from the plant proved inaccurate.
However, the science ministry and the government’s nuclear safety agency generated data by assuming the amount of radioactive substances — which could have helped local governments and people to choose more appropriate evacuation routes.
The new Diet-appointed panel also vowed the same day to use its subpoena powers to probe deeper into the accident than the government’s investigation.
The panel, appointed by the Diet last month, has gained attention because of its membership, which includes outspoken critics of the nation’s nuclear policy who long ago questioned the seismic risks to the country’s 54 nuclear reactors.
It is expected to examine the extent to which the earthquake contributed to the crisis at the Fukushima No. 1 power plant, as well as the tsunami and radiation alert system. Interim reports by the government and Tokyo Electric Power Co. focused on the tsunami and deny the quake itself caused damage that led to fires, reactor meltdowns and radiation leaks from the plant.
The panel includes legal, nuclear and medical experts. Seismologist Katsuhiko Ishibashi has long warned of tsunami risks to the nation’s reactors — all of which are on coastlines.