CO-OPERATIVE Retail Trading Group has acted quickly to withdraw all one-litre batches of Co-op Low Calorie Bitter Lemon after a survey by the Food Standards Agency said the product contained significant traces of the chemical, benzene. According to the FSA, the survey of 150 soft drinks on sale in the UK showed that four products contained benzene levels above the World Health Organisation guidelines for drinking water and called on retaliers to withdraw the drinks from stores.