The ballot measure was leading in a statewide poll conducted in early September. But the latest Elway Poll of 413 registered voters showed momentum was shifting because of a blitz of opposition ads, The Seattle Times reported. The Elway survey of interviews conducted Oct. 15-17 showed the measure winning 46 to 42 percent, with 12 percent of voters still undecided. The margin of error was plus or minus 5 percentage points. On Friday, DuPont Pioneer also gave $460,000 to the anti-labeling group, bringing the company's total to about $3.9 million. Aside from the Grocery Manufacturers Association, top contributors include Monsanto Co., DuPont Pioneer, Bayer Cropscience and Dow Agrosciences. Dr. Bronner's Magic Soaps is the top contributor to the pro-labeling group, giving $1.7 million.