DUMMIES which can kill are still on sale in Hong Kong despite a new law supposedly banning them, the Consumer Council warned yesterday. ''Parents should check what their children are using, and if in doubt, throw it out,'' said the council's publicity and community relations chairman Anthony Yuen Yak-tim. The council bought 22 brands of dummy in shops all over the territory, and found that 13 failed vital safety tests set out in the new Toys and Children's Products Safety Ordinance. In half these cases, the ventilation holes on the dummy were too small so that if a baby swallowed one it could suffocate. Others had a safety ring so small it would be difficult to pull out of a baby's mouth if it was swallowed. Altogether the council fully endorsed only four brands: Avent, Mothercare, Nuk and Sassy. Mr Yuen said although dangerous dummies were on sale today, with the new law in place and continuous monitoring by the Customs and Excise department and the Consumer Council then eventually these products would disappear from the shelves. The council also issued a warning about many kinds of stacking chairs found in Hong Kong's restaurants. Mr Yuen said the chairs' legs were not bolted to the seat but only welded on. These welds could weaken and fracture, causing the chair to collapse. In America, there were at least 26 cases of people falling and suffering serious back injuries and broken bones, he said, though so far there were no documented cases in Hong Kong.