The United States has aggressively rebuffed a draft report from the North American Commission for Environmental Cooperation, which recommends more care to ensure genetically modified maize does not contaminate natural strains.

Washington was angered when the report was leaked before its officials could review its contents, along with other North American Free Trade Area countries, Mexico and Canada.

The report, for instance, recommends US corn exports to Mexico be milled at the border. This, said the US government, "would increase the cost of US corn significantly, negatively affecting Mexico's livestock producers and consumers. Milling corn before transport also raises quality concerns and increases shipping costs, exacerbating the problem."