Japan’s evacuation map now resembles not a circle but a paw print, with a growing number of finger-like projections. On Thursday, Chief Cabinet Secretary Yukio Edano recommended the evacuation of several emerging hot spots beyond the government-ordered 12.5-mile evacuation zone around the Fukushima Daiichi plant. These hot spots — some as far as 35 miles from the facility — could receive more than 20,000 microsieverts of radiation in a year, surpassing the internationally recognized limit for adult exposure, Edano said.
Instead of basing its evacuation recommendations on simple geography, the government is now opting for a hyper-detailed evaluation that underscores the randomness of radioactive patterns. On Saturday, the government said new hot spot areas would be analyzed on a house-by-house basis, a tacit acknowledgment that the formula for projecting long-term exposure relies too much on estimation and should not be the sole factor in determining whether residents stay or leave.
As Ohara residents like Ichiro Tani, 62, and Toyoaki Matsushita, 54 — longtime friends — now know, estimating one’s radiation risk is a fraught undertaking. In their mountainside town, a cluster of 120 households about 19 miles from the plant, levels fluctuate drastically within a few blocks.
One resident, Toshihiko Nakano, ordered a Ukraine-made dosimeter and walks every Saturday from house to house, recording the measurements.
In one front yard: 3.65 microsieverts per hour.
In another: 11.3 microsieverts per hour.
The local government began paying serious attention to this area only on May 1. That’s when Minamisoma, the closest city to Ohara, began daily radiation monitoring, with two workers making eight-hour driving tours, stopping at 36 predetermined places.
Every afternoon about 1:30, the local government crew arrives at an abandoned gravel lot just a stone’s throw from Tani’s house. On Thursday, as Tani and Matshushita smoked cigarettes nearby, the workers held a dosimeter one centimeter above the ground, then recorded the digits. They repeated the process, holding the dosimeter one meter above the ground.
“What have we got today?” Tani asked.
“It’s even higher today than normal,” one of the workers said.
The number, taken from waist-level: 3.76 microsieverts per hour.
“Oh, pretty big,” Tani said.
For Tani and his neighbors, these numbers no longer seem like industry-speak abstractions. But they have struggled to put the figures into context — a common problem during these last months as the government has issued reams of data but little practical information.