ence. In 1998, the World Health Organisation decided to slash the safe level for human exposure. Even at the new level of between one and four picograms per kilogram of body weight (a picogram is a millionth of a millionth of a gram) - they were still anxious that "subtle effects may already occur in the general population in developed countries".
Cancer is not the only worry, and other health damage from dioxins has been slightly easier to substantiate. The EPA report will link low-grade dioxin exposure to a variety of problems, including hormonal changes and developmental defects in babies. It states: "It is likely that part of the general population is at, or near, exposure levels where adverse effects can be anticipated."
Risk to babies
Rick Hind, the legislative director for Greenpeace's toxics campaign, which yesterday wrote to the EPA demanding a Dioxin emergency action plan, said: "This means that dioxin levels in the bodies of newborn babies are already at levels that put them at risk of serious illness."
There have been concerns for some time about the high levels of dioxins in human breast milk, although environmental and health groups continue to urge women that the risks do not outweigh the benefits of breastfeeding.
Experts from the Imperial Cancer Research Fund (ICRF) and the Cancer Research Campaign (CRC) in London yesterday agreed that dioxins were a cause of anxiety.
"We know that dioxins are in general highly toxic and can cause cancer," said Tim Key of the ICRF cancer epidemiology unit in Oxford. But more is unknown than known.
"The whole area is full of uncertainty and particularly in relation to cancer," said Lesley Walker of the CRC.