A California initiative to require labeling of foods containing genetically modified ingredients appeared headed for the ballot in November after organizers said on Wed nesday they had gathered nearly 1 million signatures in favor of the measure.

The hotly contested proposal is similar to measures being pushed in other U.S. states and at the federal level as GMO opponents demand more transparency in food products.

The California measure would require labeling of foods made with biotech corn, soybeans, canola, or other biotech crops to specify that they were "produced with genetic engineering."

More than 971,000 people signed the "Right to Know" petition, far more than the 555,236 needed to qualify for the November 6 ballot, said Stacy Malkan, spokeswoman for the ballot initiative.

"The right to know is a fundamental right and a bedrock American value," Malkan said in a statement issued on Wednesday. "The voters of California will surely vindicate our right to know what's in the food we eat and feed our children."

Most processed foods sold in the United States are made at least in part with genetically modified crops. Monsanto is the world leader in development of such crops, which are grown in many countries around the world.

These transgenic crops, which contain genes from other species, have become popular with farmers because biotech companies have altered the plants to make them more resistant to insects and more able to withstand weed-killing chemicals.

But many health, environment and consumer advocates say such crops can damage the environment and hurt animal and human health. Labeling would allow consumers to know what they were purchasing and eating, they say.

Monsanto and other players in the biotech crop industry, as well as food companies and retailers, oppose labeling measures, saying they would be costly and confusing to consumers. They claim labeling is not needed because biotech crops are well regulated and safe and accuse labeling proponents of using scare tactics and inaccurate information.

"Biotech foods don't need to have a specific label," said Karen Batra, spokeswoman for the Biotechnology Industry Organization (BIO).

"This isn't even about labeling. It is under the guise of labeling," Batra said. "It is about disparaging mainstream agriculture, scaring consumers into paying a premium price for organic products."