As temperatures soared to 100 degrees Fahrenheit on a recent July morning, school children in Fukushima prefecture were taking off their masks and running around playgrounds in T-shirts, exposing them to a similar amount of annual radiation as a worker in a nuclear power plant.
Toshinori Shishido, a Japanese literature teacher of 25 years, had warned his students two months ago to wear surgical masks and keep their skin covered with long-sleeved shirts. His advice went unheeded, not because of the weather but because his school told him not to alarm students. Shishido quit this week.
"I want to get away from this situation where I'm not even allowed to alert children about radiation exposure," said Shishido, a 48-year-old teacher who taught at Fukushima Nishi High School. "Now I'm free to talk about the risks."
After the March 11 earthquake and tsunami devastated the Tohoku region in Japan's northeast, the central government evacuated as many as 470,000 residents, including 160,000 because of radiation risks from the crippled Dai-Ichi nuclear plant. More than 2 million residents including 271,000 children remain in Fukushima, Japan's third-biggest prefecture by size.
The government is closely monitoring radiation levels, said Yoshiaki Ishida, an official at the Ministry of Education.
"We don't think we are at a stage to tell Fukushima people to evacuate at this moment," Ishida said.
Kiyoharu Furukawa, 57, assistant principal at Fukushima Nishi High, said the school told Shishido not to spend too much time talking about radiation during his classes as some students and parents complained. He confirmed Shishido resigned.
Radiation can damage human cells and DNA, with prolonged exposure causing leukemia and other forms of cancer, according to the World Nuclear Association. Children are more susceptible as their cells grow at a faster rate.
"It's all invisible. The trees are still trees, people are shopping, the birds are singing and dogs are walking in the street," said Chris Busby, a visiting professor at the University of Ulster's school of biomedical sciences, who visited Fukushima prefecture last week to provide information on health risks. "When you bring out the (Geiger) machines, you can see everything is sparkling and everyone is being bitten by invisible snakes that will eventually kill them."
Shishido will leave Fukushima for Sapporo, on the northern island of Hokkaido, on Aug. 8 to join his wife and two children aged 13 and 10, he said. The teacher aims to create a network there to help the 3,000 evacuees from Fukushima find jobs.
Hokkaido is offering 2,140 apartments in public housing, some rent-free, to evacuees from Fukushima, Miyagi, Iwate and other prefectures affected by the quake and tsunami, said Toshifumi Imai, a Hokkaido housing official. The government also offers loans of as much as 500,000 yen ($6,400) without interest, he said.
"People in Hokkaido were supposed to take the public housing," said Imai. "Most of them are still available."
Shishido said he was instructed by school officials not to tell his students that they should wear masks or about how radiation would affect their health. He deleted some comments from his blog after receiving those orders in May.
"I saw little boys playing baseball in a cloud of dust, and I wondered who can protect their future," said Kanako Nishikata, a 33-year-old housewife with a son, aged 11, and daughter, aged 8. "It's shocking to learn a teacher is quitting because he can't protect the students."
A group of parents and children from Fukushima plan to visit Education Minister Yoshiaki Takaki in Tokyo on Aug. 17 to ask him to evacuate children from the prefecture, she said.
Fukushima Nishi High, which has 873 students, had readings of 0.07 microsieverts per hour in the school building and 1.5 microsieverts per hour in the playground on July 14, still within the safety limits set by the prefecture and government, Furukawa, the assistant principal said. The school continues to hold gym classes and sports club activities outside, he said.
"I don't think the children are safe either, and I know the radiation level is still high," Furukawa said. "These days, they are wearing short sleeves and no masks."
An official at the Fukushima Prefectural Board of Education, who didn't want to be identified, said he was surprised that Fukushima Nishi High clamped down on Shishido's views. The board has sent counselors to the 301 schools it oversees to ensure that children are not suffering from mental problems, the official said. The board also asks students and teachers to wash their hands and gargle after playing outside, the official said.
About a fifth of the 1,600 schools in Fukushima are exposed to at least 20 millisieverts of radiation a year, the Network to Protect Fukushima Children from Radiation said, citing the most recent government readings in April. That's the limit for an atomic plant worker set by the International Commission on Radiological Protection.
More than three-quarters of the schools receive radiation readings of 0.6 microsievert per hour, said the network, a group comprising 700 parents. That's 10 times more than the readings in Shinjuku, central Tokyo, on average.
Miyuki Sato, a 36-year-old housewife who evacuated to Kyoto this week with her two children, attended a town hall with government officials in Fukushima on July 19. She said that even after leaving her home, she still has a 120,000 yen monthly mortgage to pay off.
"You may say we should keep children at home if we think it's dangerous, but kids need to play outside if they want to pick flowers or collect beetles," said the mother of a 9-year- old son and a year-old daughter. "Please get all the children out of Fukushima. Please offer financial aid for us."