A United Nations rights investigator said today that Japan hasn't done enough to protect the health of residents and workers affected by the Fukushima nuclear accident.

Anand Grover, UN special rapporteur on the right to health, said the government has adopted overly optimistic views of radiation risks and has conducted only limited health checks after the partial meltdowns at several reactors at the Fukushima Dai-ichi nuclear power plant caused by an earthquake and tsunami in 2011.

'The government has to err on the side of caution and be inclusive.'—Anand Grover, UN special rapporteur on the right to health

Several investigations, including one conducted by a parliament-appointed panel, have criticized the government for alleged coverups and delays in disclosing key radiation information, causing evacuees to be unnecessarily exposed to radiation. That has also caused deep-rooted public distrust of the government and nuclear industry.

Although he welcomed ongoing health checks of affected residents, Grover said they were too narrow in scope because they are only intended to cover Fukushima's two million people, and that only children are being given thyroid tests, even though the impact of radiation went far beyond Fukushima's borders.

He said the health survey should cover "all radiation-affected zones" stretching across much of the northeastern half of the main Japanese island of Honshu. So far, only ¼ of Fukushima's population has been covered.

Many nuclear plant workers on short-term contracts have no access to permanent health checks, and many residents complained that they have not been allowed access to their own health-check results, Grover said.

Chornobyl not good example

"The scope of the survey is unfortunately narrow as they draw on the limited lessons from the Chornobyl accident and ignore epidemiological studies that point to cancer as well as other diseases in low-dosage radiation," Grover said.

He said the government's use of a radiation threshold of 20 millisieverts per year — an annual cap set for nuclear industry workers that is more than 10 times the three-year limit for ordinary citizens — in determining off-limits areas around the plant conveys a misleading message that doses up to that level are safe. The government has emphasized that message by saying in official publications, school booklets and in conferences that there is no clear evidence of a direct risk of cancer if a person is exposed to radiation doses of up to five times that level.

He said in Chornobyl, the obligatory resettlement threshold limit was just a quarter of Japan's.

There are some studies that say radiation exposures of up to 100 millisieverts per year show no clear evidence of higher cancer risks, he said.

"But that is controversial. And there are a lot of studies which indicate otherwise. The government need not say which is right. The government has to err on the side of caution and be inclusive," he said.

Doctors at Fukushima Medical University say the estimated radiation exposure from the Fukushima accident was much smaller than from the 1986 Chornobyl nuclear disaster, and that an increased risk of thyroid cancer among children is unlikely.

In September, they found thyroid cancer in a teenage girl — the first case in checkups following the Fukushima crisis. But Shinichi Suzuki, a thyroid expert at the university, said he believes it was too early for radiation from Fukushima to have been responsible because it took about four years before the first cases of thyroid cancer began appearing among children after Chornobyl.

Grover also said the government should work harder to include residents in decision-making, monitoring and implementation of measures that affect their health.

"I personally think experts only know part of the real situation. Communities must be involved," he said.

Grover wrapped up an 11-day survey in Fukushima and other areas Monday after submitting a draft interim report of his findings to the government. A final report is to be released next June.