Explaining the rise of 400 per cent cases of leukaemia, Raymond Liang Hin-Suen of the University of Hong Kong has recently postulated the incidence of the malady with exposure to organic solvents. "There is no hard evidence," he warned, "but there is suspicion." He had studied 67 patients.

The Hong Kong researcher noted that there was a rise in bone marrow cancer among local residents annually numbering from 10 in 1980 to 40 till today. His team diagnosed a 'myelodysplastic syndrome'- better known as an effect of exposure to high-dose radiation. "We are these seeing a pre-leukaemia, symptoms," says Lang, 'When you look at the bone marrow, their red cells and white cells are all affected. This is commonly seen in radiation, in victims of atomic bombs."

Treatment of this fatal disease is very difficult. Initially, patients visit the hospital only to receive transfusions. If their condition deteriorates, they are hospitalised. Younger patients can get bone marrow transplants, although this operation gives them less than 30 per cent chance of survival.

Two Hong Kong hospitals are investigating these patients' previous working conditions and exposure to chemicals. As most of them were found to be unexposed to radiation, the medicos bad to look for other explanations.

Liang noted that his patients were exposed to petroleum-derived organic chemicals and solvents. These included kerosene used for cooking, organic solvents in paints and lacquers and benzene. Claiming the research to be of a very general character, Liang said efforts are on to chart each patient's history of over-exposure to different chemicals.