DENVER -

A proposal requiring genetically modified food to be labeled is headed to Colorado's ballot.

Secretary of State Scott Gessler said Wednesday that backers of the proposal have collected enough valid signatures to place Proposition 105 on November's ballot. The petition had over 171,000 signatures, nearly twice as much as required, though some were rejected.
    
Earlier this year, Colorado lawmakers rejected a proposal asking food producers to voluntarily label food made with genetically modified crops, known as GMOs.
    
Voters in Oregon will also get to decide this fall whether to require GMO labels.
    
Vermont, Connecticut and Maine already require them.