December Tueller, from left, Caroline White and Brandon Schilling protested genetically modified foods on the steps of the Jackson County Court House in Medford, Ore., in January 2013. (Jamie Lusch/The Mail Tribune/AP, File)

An Election Day measure asking Oregon voters whether genetically modified foods should be labeled as such may be headed to a recount.

Initial results suggested the measure had failed, as had a similar measure in Colorado. The food ndustry funneled money into both states, making the Oregon battle the most expensive ballot fight in state history.

But newly counted ballots narrowed the margin of defeat to 0.1 percent, within the state’s 0.2 percent automatic recount threshold, according to the Associated Press. As of Thursday, fewer than 1,500 votes separate both sides. A recount isn’t assured, however, as counties have until 5 p.m. Monday to submit final results, and thousands of ballots have yet to be reported. If a recount happens, the state expects it to begin in early December.

The narrowing of the margin was thanks in part to challenges by proponents of labeling to identify “challenge ballots,” as the Oregonian’s Jeff Mapes explains:

Those are ballots in which the signature of the voter doesn’t match the signature on file or in which the voter neglected to sign the ballot.

There were just over 13,000 challenge ballots around the state, and Measure 92 supporters launched a major effort to get voters to go to their county elections office to sign their ballot or to send in a new voter registration card showing how their signature looks now.

If Oregon were to pass the measure, it would become only the second state to have a GMO labeling law on the books with a set start date. Vermont’s legislature passed the first this spring. Connecticut and Maine passed similar laws, but both go into effect only if four other states — which, for Maine, must be contiguous — pass labeling requirements. GMO bills have been taken up in more than half the states, though success has been hard to come by.

The food and grocery industry has been highly active in taking on labeling measures. The Vermont law was sued shortly after its passage — as everyone anticipated — by the Grocery Manufacturers Association, Snack Food Association, International Dairy Foods Association and the National Association of Manufacturers.

DuPont Pioneer, Monsanto, PepsiCo, Inc., Coca-Cola and Kraft were the top five contributors to the campaign against Oregon’s measure. In Colorado, all but one were also among the top contributors, with DuPont being swapped out for General Mills.

A similar ballot fight last year in Washington was also the most expensive in that state’s history, with Monsanto, DuPont Pioneer, Pepsi Co., Bayer CropScience and Nestle USA leading the successful fight against it.