Foam sofa stuffing banned in Britain and the United States was the catalyst for the Mei Foo blaze which killed nine people last April, a government chemist said yesterday. Cheung Kwok-keung told the inquest that the toxic smoke produced by burning polyurethane foam also contributed to the deaths of the victims. 'Once polyurethane foam is involved with fire, it produces toxic, smelly smoke,' Mr Cheung said. 'It can burn extremely fiercely and has been found to be responsible for a number of extraordinarily rapidly developing fires.' Mr Cheung said the fire in Mei Foo Sun Chuen on April 8 started when a cigarette ignited a foam sofa on the sixth floor. The blaze spread up to the 12th floor. Although polyurethane stuffing has not been banned, the Consumer Council has urged importers to run tests or modify the material. 'What began as a smouldering fire led to heat building up in the material, until it burst into flames,' Mr Cheung said. 'Fire laws in England and the US have banned this plastic, although there has been no legislation in Hong Kong. 'If the sofa had been made of some other material that could not be so easily ignited by a cigarette, this tragedy would not have happened so easily.' The flammability of the foam gave residents little time to escape, he said. Mr Cheung added that it was ultimately the toxic smoke which killed most of the victims. Malfunctioning spring hinges on fire doors worsened the situation, leading to the fire spreading much more quickly, he told the court. 'Those who tried to escape their homes, and stayed in the smoky environment, became incapacitated by the smoke and collapsed. Those who did remain in their flats did not suffer much,' he said. Mr Cheung said the public needed to be educated about the potential dangers of materials used by furniture makers. The inquest before Coroner Ian Thomas continues today.