There is evidence that refined soy oil derived from genetically modified soybeans contains glyphosate residues. In fact, the refined oils have a higher concentration of glyphosate than the crude oil.
On Saturday, September 21, 2013, the Seattle Times published a statement by R. James Cook. In his argument against Washington state Initiative-522 to label genetically modified foods (GMOs), Dr. Cook stated,
“Common genetically engineered food crops grown in the U.S. today include corn, canola, soy and sugar beets. Purified food ingredients such as sugars or oils derived from these crops are indistinguishable from ingredients derived from conventional or organic varieties. Importantly, there are no genetically engineered content or traits in these purified ingredients. Yet I-522 would require food products that include these purified ingredients to be labeled even if the food itself is not genetically engineered and has no genetically engineered content.”
It is true that Monsanto makes the claim that there are no detectable residues of glyphosate (active ingredient in Roundup) in refined sugars and oils derived from GMOs. In this 2003 document from Monsanto Brussels, the glyphosate levels in sugar and oil are stated at below the level of detection, which they claim is 0.05 parts per million (ppm).
On a side note, Dr. Rosemary Mason reported results on glyphosate in drinking water in Wales in parts per trillion (ppt) obtained from a German laboratory. Are we to believe that Monsanto doesn't have or have access to state-of-the-art equipment?