A group of workers who claim they developed cancer through their jobs at IBM are to begin legal action in California, revealed a report today.

Three former IBM employees and the family of a fourth, who has since died, say they were exposed to dangerous chemicals through their work in "clean rooms", dust free areas where microchips and other electronic parts are made.

According to the report, the case could be the first of hundreds of actions by former employees of IBM and other electronics countries both in the US and the UK, with enormous financial implications.

The case follows years of argument over the safety of working in clean rooms. Lawyers for the group argue that the former employees developed cancer after being exposed to a range of poisonous chemicals day after day, said the report.

The workers say IBM's own records show that over a period of years, workers in the company's clean rooms developed more of certain types of cancer and died younger than the rest of the population.

IBM denies this totally.

The hearing, in California's Silicone Valley, is expected to last several months, according to the report.