House Doctor

ASBESTOS, lead, pesticides - who will protect us from these hazards? This week's decision by the Health and Safety Executive to tighten the restrictions on white asbestos should act as a reminder that many building materials, previously thought to be safe, later turn out to be serious health hazards.

The more dangerous blue and brown types of asbestos have been banned since 1985, but the white version, present in many buildings in the form of asbestos cement sheets, corrugated roofing and textured paints, was not thought to be dangerous.

Now research has found that it, too, can cause lung diseases and cancer, the effects perhaps only emerging 40 years after initial contact.

Other materials which were once thought to be safe include lead in paint and water pipes, and white spirit. MDF (Medium Density Fibreboard) is also suspected of being more dangerous than previously thought.

Unfortunately, exposure to these materials can be more dangerous within the home than at work - because the home is a closed environment, and also the place where children spend most of their time.

The sad thing about these dangerous materials is that it takes such a long time to get them recognised as hazardous, and for action to be taken to protect the public. Doubts were first expressed about lead paint while Queen Victoria was on the throne, but it took until 1992 for it to be banned in Britain.

And now the HSE in London has been told that common pesticides probably represent the most serious environmental problem in the industrialised world. Professor Nicholas Ashford, a UN health advisor, said that permethrin - sprayed in around 5,000 British homes a week as a woodworm treatment - may be responsible for initiating the illness known as multiple chemical sensitivity, which causes sufferers to become affected by exposure to tiny amounts of other common substances, such as perfume, traffic fumes and tobacco smoke.

Professor Ashford introduced a new theory of the illness, which he calls Toxicant Induced Loss of Tolerance. It explains why some sensitised patients react to levels of chemicals so low that they are undetectable by the usual laboratory testing methods. This means that their symptoms baffle doctors who, unable to diagnose a classic cause-and-effect illness, conclude that the illness must be a mental problem. Indeed, studies have shown that women who complain about headaches, skin rashes and breathing problems after exposure to timber treatment chemicals are often prescribed tranquillisers, or sent for counselling.

(Men, who most doctors seem to think must be more emotionally stable, are more likely to be diagnosed as suffering from a viral infection when they report the same set of symptoms.)

In the light of Professor Ashford's startling theory, we can only hope that the HSE acts fast to commission some research into the health effects of pesticides in the home, and that they also act on his call to cut pesticide use until the answers are known.

Above all, let's hope that, unlike the lead and asbestos problems, this time it won't be several decades before the right decisions are taken.