French Farm Minister Jean Glavany last week ordered the withdrawal of atrazine and related weedkillers, saying the chemicals were building up in water supplies and threatening human health. Switzerland's Syngenta AG, and privately held Makteshim of Israel and Sipcam-Oxon of Italy are the world's biggest producers of the chemicals, according to French plant protection industry group UIPP. The group denied there were possible health problems associated with triazines in water supplies and said the withdrawal of the chemicals would deal a heavy blow to both the plant protection industry and to farmers.