A U.S. regulation passed in 2011 has increased the established tolerance for residues of the herbicide glyphosate on corn. The new regulation was a result of lobbying by the Monsanto Company.
The tolerance is even higher than the one allowed by international standards. The Codex Alimentarius Commission has established an maximum residue level for glyphosate on corn at 5 parts per million, but the U.S. regulation sets it at 13 parts per million.
According to the Federal Register:
“The U.S. tolerance of 13 ppm for corn ... is necessarily higher than the Codex [maximum residue level] to account for residues of both glyphosate and its metabolite N-acetyl glyphosate. N-acetyl glyphosate is found in genetically modified (GMO) glyphosate-resistant commodities, including corn, grown in the U.S.”