WASHINGTON — Opponents of I-522, a measure on Washington state ballots to require labeling for food and beverage products with bioengineered ingredients, are declaring victory based on early results from the Nov. 5 election, but supporters of the initiative still await the final tally.

As of late Nov. 5, the vote was 54.8% against labeling and 45.2% in favor.

The Grocery Manufacturers Association (G.M.A.), a contributor to the state-record $22 million “No on 522” campaign, said the proposal would have misled consumers and raised food costs for Washington families.

“Genetically modified food ingredients are safe, good for the environment, reduce the cost of food and help feed a growing global population of seven billion,” said Pamela Bailey, president and chief executive officer of G.M.A. “Because a 50-state patchwork of G.M.O. labeling laws would be confusing and costly to consumers, G.M.A. will advocate for a federal solution that will protect consumers by ensuring that the F.D.A., America's leading food safety authority, sets national standards for the safety and labeling of products made with G.M.O. ingredients. Our country’s labeling laws have been and should continue to be based on health, safety and nutritional content.”

Had I-522 passed, Washington would have become the first state to implement labeling of bioengineered foods.

Earlier this year, G.M.A. launched www.FactsAboutGMOs.org, a web site defending the use of bioengineered ingredients by addressing questions regarding their safety, prevalence and benefits.

“We will continue to oppose individual state efforts to impose mandatory labeling of products made with G.M.O. technology, as well as advocate for the safe and effective use of this important technology to increase the food supply while lowering cost,” Ms. Bailey said. “And we will continue to engage in an informative dialogue with our consumers on the safety, prevalence and benefits of that technology.”

Supporters of the measure, however, insist results from the mail-in election are still too close to call.

A Nov. 6 message on the Facebook page of campaign group “Yes on 522” said: “Washington votes by mail, so it takes a couple of days to get all of the results. As of last night there were hundreds of thousands of votes that still needed to be counted.”