Washington was billed as the national testing ground on the issue of genetically modified foods, which draws spirited supporters and detractors into the debate over their effects on human health and the environment.

If the state's vote tally is to be believed, it appears the Evergreen State won't get special labeling for GMO foods, as expected before the Tuesday vote.

Those in favor of the initiative, however, say don't count your genetically engineered chickens before they hatch, according to a news release that reads rather victoriously, considering the Washington secretary of state's office says the measure failed 55% to 45%.

"The campaign remains confident that a majority of Washington voters support labeling of genetically engineered foods, and optimistic about supporters getting out to vote in this off-year election," said the Yes on Initiative 522 release.

"For now, the votes are too close to call," reads the Yes on I-522 landing page. "Over the next few days more ballots will be counted and we will keep you posted as we learn more."

The secretary of state's website says 100% of the vote has been counted.

The vote, if confirmed, would mark a defeat for those who say GMO foods may pose health risks and lead to a spike in herbicide and pesticide usage. The Elway Poll in October reported that Washington voters were in favor of the initiative by four percentage points.

The vote would have made Washington the third state to require GMO labeling and the first to pass an initiative that will go into effect regardless of whether other states enact similar laws.

Placed on the ballot after Washington voters submitted more than 350,000 signatures, I-522 "would require most raw agricultural commodities, processed foods, and seeds and seed stocks, if produced using genetic engineering as defined, to be labeled as genetically engineered when offered for retail sale."

Yes on I-522 says it is "motivated by a very simple principle: People have the right to know what's in the food they eat and feed their families."

Sixty-four countries have passed laws allowing consumers to know when there are GMO ingredients in their food, according to the Center for Food Safety. The watchdog group says the "limited data" on GMO foods indicates that the foods lead to higher risks of "toxicity, allergenicity, antibiotic resistance and immune suppression."

Since genetically engineered foods entered the U.S. market, herbicide use on corn, soybeans and cotton has increased by 527 million pounds, the center said, citing a study by Environmental Science Europe.

Monsanto, a Missouri-based agricultural giant that was staunchly opposed to the measure, says on its website, GMOanswers.com, that the crops have led to lower pesticide usage. The company says it's also invested more than $100 million to ensure the products are safe.

"Humans, over our history, have altered all of our crops, often for taste or yield or disease resistance," the website says.

"Before they reach the market, crops from GM seeds are studied extensively to make sure they are safe for people, animals and the environment," the Monsanto site adds. "Today's GM products are the most researched and tested agricultural products in history."

Opponents spent more than $22 million to fight the legislation -- more than triple what those in favor of labeling spent -- with only $600 of that money coming from within the state. Monsanto contributed more than $5 million, the Washington Public Disclosure Commission said.

Twenty-three states have pending legislation regarding GMO labeling, according to the group Right to Know GMO. Maine and Connecticut in June passed laws requiring labeling, but they won't go into effect until other states pass GMO-labeling laws.

California last year shot down such a law with 51.4% of voters casting ballots against it.

The U.S. Department of Agriculture Food Safety and Inspection Service approved a non-GMO label for meat and liquid egg products in June, the first time the department has approved such a label from a third party. GMO foods were approved for human consumption in 1995, but the Food and Drug Administration never required any labels pointing them out as such.

CNN's Greg Botelho contributed to this report.