He is the man appointed by Tony Blair to protect the public from poisonous chemicals. Yet the rural affairs minister, Alun Michael, has admitted that his body contains a cocktail of toxic substances, many of which have been banned on safety grounds for decades.

The minister agreed to have the results of his blood test published to make people aware of the issue of pollutants and chemicals contained in everyday items such as sofas, cosmetics, mattresses and televisions.

Tests on the enthusiastic hill-walker and keen supporter of organic food detected 33 hazardous man-made compounds in his blood, including pesticides, flame retardants and industrial plastics.

What is worrying campaigners is that more than 90 per cent of these have been banned, some as long ago as the 1970s, after being linked to cancer, immune-system disorders and neurological problems.

The findings have been described as proof that no one is safe from the build-up of harmful chemicals in the environment, even if the actual contamination occurred decades ago.

The precise health implications remain unknown because many of the chemicals have never been tested on humans. In addition, a method for calculating the cocktail effects of chemicals once they are in the bloodstream has yet to be devised.

Michael admitted that his results served as evidence that everybody in Britain was being exposed to chemical contamination, but said the levels were extremely low and should not be a cause for immediate alarm. 'It does demonstrate the range of chemicals to which we are exposed,' he added.

Sir Tom Blundell, the biochemist appointed by Tony Blair to chair the Royal Commission on Environmental Pollution, warned that Michael's results would fuel a growing consensus that the prevalence of untested chemicals in the environment could become a major public health issue. Blundell said he had repeatedly warned ministers that the issue could become the 'next tobacco'.

'We are conducting a huge experiment on ourselves and I am not surprised that a large number of chemi cals have accumulated in the tissues of Mr Michael,' he said.

One of the substances found in the minister's body belongs to a family of chemicals including perfluorooctane sulphonate, used in chrome plating and fire-fighting foam, which the minister banned only last Tuesday.

Announcing his decision to start phasing out the chemical, which has linked to bladder cancer, Michael described it as a substance that 'presents a real and significant risk to the health of the population and the environment in the UK. I am concerned that a substance with these intrinsic properties is still used.'

Sixty milligrams of blood were taken from Michael and analysed for 103 industrial substances linked to health concerns. He agreed to undertake the tests in order to raise the issue at a time when Britain is pushing for tighter regulation.

Blundell believes the government must act quickly if it is to sidestep litigation. 'The health of millions could be affected by these chemicals and there could be some very serious outcomes. At the moment it remains very difficult to prove the relationship between cause and affect, but that could change,' he warned.

Dr Vyvyan Howard, a toxicologist at Liverpool University and a member of the government's advisory committee on pesticides, said: 'Asbestos was known to be bad in about the 1900s, but it still took 60 or 70 years to stop its use. People are going to die in the next 20 years because of decisions already taken.' Although the levels of contaminants in the minister's blood were small, Howard said they could 'hijack the development' of a foetus.

Elizabeth Salter-Green, chemical campaigner for environmental pressure group WWF, which organised the tests on the minister, said: 'If Alun Michael was a pregnant mother, it is not unreasonable to assume there could be effects on the foetus. The fact their health effects are completely unknown is ridiculous in the 21st century.'

Other chemicals in the blood of the former marathon runner included polychlorinated biphenyls, which have been banned over concerns that they could cause infertility.

'We know that in animals some of these substances increase the incidence of cancer,' Howard said.

'Temporally and biologically, it is plausible these chemicals may play a role.'

Chemical firms reject claims they are poisoning people and Department of Health officials who examined Michael's results told him there was 'no evidence that such trace amounts have adverse effects on health'. Such guidance has angered experts who claim that government officials had no evidence to substantiate these claims.

Legislation on the chemicals industry is under consideration by the European Commission, a move that would place the onus on the industry to prove that the everyday use of 30,000 substances is safe. Britain has taken a lead on pushing through the proposals, according to Michael, and has pulled together both environmental groups and industry to agree on a new testing procedure for toxic substances.

However, the plans will have to survive lobbying from US interests. A confidential memo seen by The Observer reveals how the US has campaigned aggressively against any crackdown on the industry, arguing it would affect the £20 billion of chemicals that America exports to Europe each year.