Data from a 1950s survey showing some 13,000 people claimed they were exposed to radioactive rain after the bombings of Hiroshima and Nagasaki has surfaced, and the government is being asked to use the data to study the effects of such rain on people’s health.

The Radiation Effects Research Foundation (RERF) revealed the data after prodding by a Nagasaki doctors’ association. On Nov. 8, the Nagasaki doctors’ association sent a request to the health ministry, which manages the RERF.

According to the RERF, in the 1950s its former incarnation, the Atomic Bomb Casualty Commission, conducted a “life span study” on around 120,000 people. In response to a question about exposure to fallout rain, about 13,000 people responded that they had been exposed. Almost all of those people had been at the Hiroshima bombing, but around 800 were at the Nagasaki bombing.

Analysis has not been carried out on the health effects of so-called “black rain,” the fallout after a nuclear explosion that is darkened by dust and soot and can carry radioactive material, and the national government’s current stance is that black rain does not affect the human body.

However, there are people in the cities of Hiroshima and Nagasaki who, after being exposed to black rain outside of the officially recognized bombing victim areas, have complained of health effects and called for expansion of the recognized areas and distribution of bombing victim booklets, which can allow for health-care assistance.

Takaya Honda, a member of the association, said, “Interest in the effects of low-dose radiation exposure has grown, especially regarding Fukushima. I would very much like for analysis on the effects to be carried out.”

Mainichi Shimbun