Negotiations between the U.S. and the European Union over genetically modified foods broke down yesterday in Geneva, furthering heightening trans-Atlantic tension and prompting the Bush administration to call on the World Trade Organization to begin hearing the dispute. At issue is a European ban on GM crops — a ban that the U.S. agricultural industry says is costing it hundreds of billions of dollars per year. The White House contends that genetically altered crops are safe and that therefore the E.U. ban is illegal and “denies choices to European consumers,” according to Richard Mills, a spokesperson for U.S. Trade Representative Robert Zoellick. The E.U. maintains that the long-term safety of GM crops remains unknown, a position that got tacit support last week with the approval of the Cartagena Protocol on Biosafety, a global treaty intended to restrict transgenic foods.