The toxicity of the liquid flea-killer which poisoned a policewoman, her two daughters and their pet dog was 100 times more than it should have been, government tests showed yesterday. The solvent used by the family to bath their pet dog was Diazinon, used to kill ticks in animals including dogs, not Amitraz as police originally believed. But the solvent was old and the strength had increased dramatically by being mixed with water after an earlier use. The mother and two daughters regained consciousness yesterday. The family bathed their mongrel Suki with the solvent in their Sai Kung home on Monday. Suki collapsed and the three took turns to give mouth-to-mouth resuscitation. They later felt unwell and were sent to hospital. Suki died. Senior chemist Dr Mok King-kuen said the original compound of Diazinon was classified as moderately toxic, slightly higher than flea wash Amitraz, which requires dilution of up to 600 times before application. But the potency of its hydrolysed product was 100 times higher than the parent compound. 'The decomposed compound is formed when water is mixed and has been left to stand for a long time,' Dr Mok said. 'It is easily absorbed through the skin and users should wear protective gloves and follow instructions closely when applying the chemical.' The substance can damage the nervous system, cause breathing problems and upset normal functions of the heart. The United States in 1988 banned its use on golf courses and parks. The mother, Chong Tak-ying, 38, was said to have obtained the drug from a friend. She and her daughters, aged 16 and 15, regained consciousness yesterday and talked briefly to their relatives and friends after being unconscious for more than 24 hours in Prince of Wales Hospital's Intensive Care Unit. Doctors warned they were not yet out of danger as the body took time to discharge poisons. When the youngest girl, Sau-chung, awoke she said: 'Dad, it's painful. The tubes hurt my throat.' The father, now remarried, said he dared not tell his daughter Suki was dead. Environmentalists renewed their call for the Government to strengthen pesticide control. 'I wish the Government could learn from this lesson. It could be hazardous not only to human beings but our birds, pets and plants,' Friends of the Earth director Mei Ng Fong Siu-mei said. She called on the Government to improve the labelling system and data base for the list of approved pesticides. Clear indications of what pesticide were being used and possible side-effects should be shown in public places.