Japan Police Probe Radioactive Ore
TOKYO (AP) _ Japanese police searched two stockpiles of radioactive ore Tuesday, looking for the source of small amounts of the material mailed anonymously to several government offices.
Envelopes containing particles of monazite, a source of the nuclear fuel thorium, were sent to the official residence of Japan’s prime minister and nine other agencies last week.
At least one of the envelopes included a message warning that radioactive materials were being sent from Japan to North Korea.
Investigators found more than 10 tons of monazite in a vacant house in Kamiina in Nagano prefecture (state), 112 miles northwest of Tokyo, a Metropolitan Police official said on condition of anonymity.
They discovered another ton in a warehouse just outside the capital, the official said. He refused to give further details, except to say that police were still investigating whether the stockpiles were illegal.
It was too early to verify whether the monazite found in storage was being sent to North Korea, he said. Police said the stockpiled monazite emitted radioactivity levels too small to be harmful to humans or the environment.
Government officials said the brown, sand-like substance was sent in amounts too small to harm humans.
The letter sent to the prime minister’s residence contained about 3 grams of powder, or about 1 micro-sievert of radioactivity _ a ``very small amount,″ according to the Science and Technology agency.
The average person is exposed to about 1,000 micro-sieverts of radioactivity a year.