 American rice exports to Europe were interrupted in 2006 when the LibertyLink modification was found in commercial rice crops, although it had not been approved for release.An investigation by the USDA's Animal and Plant Health Inspection Service (APHIS) failed to determine the cause of the contamination.In May 2013, unapproved glyphosate-resistant GM wheat (but that had been approved for human consumption) was discovered in a farm in Oregon in a field that had been planted with winter wheat.