The Health and Welfare Ministry has decided to research the effects on humans of dioxin and other toxic chemicals ingested over long periods from air and food, sources close to the ministry said June 4.

The ministry wants to set up an expert committee before the end of the month and launch a full-fledged program next year, they said. It would be the government's first attempt at a comprehensive study of the effect of dioxin on human health, the sources said.

The ministry has been obliged to launch the study because the Saitama Prefectural Government, which has a number of small-scale industrial waste disposal facilities in its area, has decided to launch its own health checkup program on dioxin in response to concerns voiced by residents over its carcinogenic effects, they said.

So far, the ministry has only conducted fact-finding surveys about dioxin emissions from domestic waste disposal facilities. There have been no studies of its effect on humans, meaning that no information is yet available, for instance, on how much a human body can accumulate before being adversely affected, they said.

Specifically, dioxin concentrations will be measured in samples of human milk and blood, where the chemical is excreted through fats, they said. Fish and shellfish, meat, vegetables and other food products will be checked to see how much dioxin they contain, because most of the dioxin in humans is believed to be taken in through foods, they said.