The forecasts were relayed to the Nuclear and Industrial Safety Agency, but they did not reach decision-makers.
In Japan, the legal responsibility for setting evacuation zones falls on the central government and the prime minister. Local officials then are tasked with implementing the orders.
Instead of following the patterns of radioactive dispersion suggested by SPEEDI, the central government simply set up a 10km evacuation zone around the plant. That did not include a broad swath of land that SPEEDI predicted would be affected.
The mayors of two towns that have since been almost completely evacuated said that the government did not inform them of even that decision — let alone provide SPEEDI data — so they had to act on their own. They said they were unable to assess the risks adequately because they were not privy to the SPEEDI reports.
“We got nothing until more than a week later,” Minami-Soma Mayor Katsunobu Sakurai said. “People were unnecessarily exposed to possible dangers. We believe the central government must come clean on this.”
“The first I heard of the 10km zone was when I saw the news on TV,” Namie Mayor Tamotsu Baba said.
Namie’s municipal government has since been evacuated to Nihonmatsu, a city 50km from the plant.
Because Karino Elementary sits just outside the 10km evacuation zone, it was used as a gathering area for evacuees.
Later in the day, at the mayor’s order, some evacuees were taken by bus to another part of Namie called Tsushima, which SPEEDI data suggested was also dangerous. Others, including the principal and his family, went in the same direction by car.
Masako Mori, a senior opposition member of parliament from Fukushima, said two alternative routes would have led away from the areas identified as high-risk by SPEEDI. The third — to Tsushima — led along the plume’s expected path.
“We didn’t have any information, but it turns out we were taking the most dangerous route,” Arakawa said. “None of us knew.”
Mori said SPEEDI data should have been used to get people out of the area much faster.
The evacuees at shelters in the Tsushima District — including about 8,000 residents of Namie — were not told to move farther away until March 16, five days into the crisis.
Mori, who also is a trial lawyer, raised the possibility of lawsuits against the government.
“The government unnecessarily exposed people to radiation, failing to observe its legal obligation to protect the citizens,” she said. “It could be held responsible for compensation for the possible damage caused by its errors.”
Exposure to radiation can lead to a variety of cancers — as it did in Chernobyl. Babies, children and pregnant women are at the highest risk.
Mori, along with Namie’s mayor and the school principal, are seeking full-body radiation tests for all children who were at the school. The tests measure internal exposure such as inhaled radioactive particles and could be key to understanding the health impact.
However, Fukushima health officials say they have no particular plan to test the Karino evacuees, because they don’t have the resources and are instead focusing on groups, such as pregnant women, from the general area.
Thousands across the region have requested full-body tests, and only 340 have gotten them so far. None had dangerously high levels of contamination, though that does not rule out future health problems.