Britain's leading poison experts united last week to denounce pressure groups for mounting a 'hysterical, scaremongering' campaign about dangerous chemicals in the environment.
They accused the groups - in particular WWF, formerly the World Wildlife Fund - of acting irresponsibly by publishing reports claiming most people have blood swimming with toxic compounds.
As these chemicals - found in plastics and pesticides - have been linked to cancers, genital ailments and other defects, Britain faces a severe health risk, it is claimed.
Next month, WWF plans to take individuals found with these chemicals to Brussels as it campaigns to introduce new chemical controls across the European Union.
But the claims of dangers were rejected by the toxicologists. 'These compounds can cause diseases but not at the levels found in these tests,' said Professor Alan Boobis, of Imperial College, London.
'Most chemicals were found at a fraction of a part per billion. There is no evidence such concentrations pose any threat to people's health. This is irresponsible, hysterical scaremongering.'
In recent years, several reports have been published by WWF, based on work at Groningen University, in the Netherlands. Using advanced blood analysis techniques, they pinpointed brominated flame retardants, found in furniture and linked to neurological conditions; phthalates, from transparent plastic wrapping, associated with genital defects; tricosan, from soap, linked with liver damage; and bisphenol A, found in plastics and associated with cancer. Some were identified in mothers of newborn babies.
These findings have then been publicised by the pressure groups, though press releases have avoided mentioning the chemicals were usually found in less than one part per per billion.
'Frankly, I would have been very surprised if they hadn't found chemicals at that level,' said Professor John Henry, also of Imperial College. 'You find flame retardant traces because we have them in our homes. That's why fire deaths have plunged. These chemicals are monuments to mankind's progress.'
But this view was disputed by Greenpeace. 'Given we have huge uncertainties about these chemicals' biological activities at low concentrations, should we be exposing the unborn child to them?' asked its spokesman, Dr Paul Johnston.
Giles Gordon, of WWF, pointed to research on animals by the University of Missouri-Columbia that linked chemicals to neurological problems, and to work at Rochester University, New York, linking phthalate traces in women to genital problems in their newborn sons.
'The Rochester study is interesting,' admitted Professor Ken Donaldson of Edinburgh University. 'But it just one study. We need many more to establish the truth.'
The Groningen studies have appeared in most newspapers, including The Observer, and have been used to back arguments that tiny traces of many different compounds could combine to produce a single effect in people. This 'chemical cocktail' hypothesis is also dismissed. 'There is simply no evidence it exists,' added Boobis.
The public is being unfairly pressured, said Professor David Coggon, of Southampton University. 'People are being pressed to make decisions on misleading information.' Donaldson agreed. 'Groups are deliberately confusing risks with hazards. A loaded gun is hazard but not a risk if locked away safely. Bisphenol A is a hazard but not in minute traces. We do not say these chemicals are completely safe but that there is no evidence - so far - to show tiny traces are unsafe.'
Scientists say they are being asked to give categorical assurances that chemical traces are absolutely safe when they can only say there is no evidence to suggest danger. This looks weak against the robust assertions of campaigners, said Fiona Fox, director of the Science Media Centre, which promotes the scientists' cause.
'These groups are more media savvy than scientists and have given themselves headlines galore by giving "terrifying" results of blood tests to a media they know has an insatiable appetite for scare stories. But it's important the public know most scientists take issue with their alarmist interpretation.'
· Additional research by Zoe Corbyn