The measure would have required that any genetically modified foods be labeled "Produced With Genetic Engineering" starting on July 1, 2016. It also would have exempted some products from that label, including animal feed, meat from animals that ate genetically modified foods, alcoholic beverages and medically prescribed foods.
The primary sponsor of the proposition, "Right To Know Colorado GMO," was largely supported by individual donations. The Sierra Club Issue Committee was also a registered issue committee supporting the proposition.
Proposition 105 backers were vastly outspent by opponents, including biotechnology giant Monsanto Co., which gave more than $4.7 million to the "NO" campaign, along with major food producers like Pepsico, Coca-Cola Monsanto, Cargill Incorporated, Kraft Foods and General Mills.
The "YES" campaign tried to make up for its lack of funding by showcasing big-name backers like Chipotle and Ben & Jerry’s ice cream company, which support GMO labeling.
Opponents called Proposition 105 a poorly written food-labeling proposal that would misinform Colorado consumers and raise food costs. They said the Colorado-only labeling program would hurt state farmers and food producers by placing them at a competitive disadvantage in the national marketplace.
Proposition supporters countered that the food labels would be simple, straightforward and similar to other labels on food products. They stressed that 64 countries around the world already require labeling of genetically engineered foods, and many U.S. food producers -- including some in Colorado -- already use labels on exports to those countries.