As the end of the most expensive campaign in Colorado history, voters have said no to mandatory labeling of genetically modified organisms (GMO).

Proposition 105 was defeated by a roughly 2-1 margin on Tuesday, according to a National Public Radio (NPR) report.

"While more than half of U.S. states have contemplated similar GMO legislation, the only one that has come close to requiring a label is Vermont. The state's law, approved this year, still faces legal challenges, and it's not slated to take effect until 2016," stated NPR.

A Denver Post report stated that "voters dished up rejection for Proposition 105, labeling of genetically modified foods, with 35 percent of votes counted."

"The measure would have required labels for GMOs — foods produced with genetic engineering or containing genetically modified ingredients. More than 68 percent of voters said no to labeling," stated the report. "Most processed foods sold in America include GMO ingredients such as corn syrup, corn oil, soybean crops and sugar."

The newspaper further reported that "supporters of GMO labeling, such as Right to Know Colorado, Whole Foods and Natural Grocers, said it would give consumers a choice about what they serve their families."

For more information, visit www.npr.org.