A chemical leak at Kwai Chung container terminal sparked an evacuation yesterday and put eight people in hospital. More than 500 workers had to be moved out to protect them from a huge plume of white vapour which formed over Terminal Four shortly before noon. As police sealed off access roads, fire-fighters wearing chemical protection suits and breathing apparatus fought to contain the leakage with sand. Fire Services Department investigators said more than 80 per cent of 320 individual drums, housed in a larger steel container, began leaking at the same time. Of the eight workers who were taken to Princess Margaret Hospital suffering from the effects of inhaling the vapour, six were released and two were in satisfactory condition late last night.