EU had already raised health doubts

In 1988, the EU banned beef from North American cattle treated with growth-promoting hormones, claiming it could harm consumers.

In 1998, the World Trade Organisation (WTO) ruled that the EU had to provide more scientific evidence, or lift their ban in 10 days. This allowed Canada and the US to punish the EU by imposing $100 million per year in tariffs on EU imports.

In October 2003, the EU delivered scientific evidence that one of the beef hormones, oestradiol, may cause cancer. The EU said those who eat beef treated with all six hormones are at risk of developing cancer, genetic problems and brain disease. Experts also warned these risks are compounded by inadequate controls in the US, where 90% of cattle producers use growth hormones, available over the counter for use without supervision.