Deaths from mesothelioma, the cancer of the lungs linked exclusively to asbestos fibre exposure, are set to reach 3,000 a year in this country by the year 2020.

Nearly all of these deaths are likely to be the result of the victims' exposure to asbestos fibres when asbestos was widely used in the construction and other industries from the 1960s until its effective ban in the 1970s.

But Kenneth Donaldson, reader in biological sciences at Napier University, warns that the risk posed by loose fibres released by a range of materials remains high. Asbestos dust is still a potential hazard to workmen in many older buildings, while new industrial materials, such as those made from glass and ceramic fibres, release dust whose potential harm has never been evaluated.

"It's an occupational problem - it's not a hazard to people in their home. If you just unroll the stuff to insulate your loft, it may irritate your skin and eyes, but that's all," Dr Donaldson stresses.

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"But it may be significant if you're working with this type of material every day for 30 or 40 years. What we don't really know is whether these new fibres are worse, the same or less toxic than asbestos."

Dr Donaldson has won three-year funding of Pounds 130,000 from the Health and Safety Executive to develop new tests specifically for fibres, using the latest advances in molecular biology.

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Dr Donaldson's team will grow lung cells under conditions that mimic the human body, and then expose these to different fibre types to look for early signs of cancer.

Before the availability of immortalised human cells, research could make only broad determinations of whether fibres could kill cells, Dr Donaldson says.

"Now we're looking for more subtle changes. It's known that asbestos is highly carcinogenic, but we want to find out why, and whether other fibres have the same properties."