The stage has been set for renewed debate over G.M.O. labeling.

WASHINGTON — Senator Barbara Boxer of California and Representative Peter DeFazio of Oregon on Feb. 12 introduced in the U.S. Senate and the House of Representatives, respectively, the Genetically Engineered Food Right-to-Know Act of 2015. The bill was similar to legislation introduced by Ms. Boxer and Mr. DeFazio in the 113th Congress, which would have required labeling of retail food manufactured through genetic engineering or whose ingredients were manufactured by genetic engineering. Those bills never came to a vote.

“Consumers have a right to know what is in the foods they eat, and parents have a right to know what they are feeding their families,” Ms. Boxer said. “This legislation will direct the Food and Drug Administration to require clear information for food that has been genetically engineered.”

Mr. DeFazio said, “We cannot continue to keep Americans in the dark about the food they eat. More than 60 other countries make it easy for consumers to choose. Why should the United States be any different? If food manufacturers stand by their product and the technology they use to make it, they should have no problem disclosing that information to consumers.”

Senator Richard Blumenthal of Connecticut joined Ms. Boxer and Mr. DeFazio at a press briefing announcing the introduction of the bills. Mr. Blumenthal added, “As a consumer and dad, I want to know whether my family is eating food that has been altered artificially in genetics — and the American public wants and deserves to know as well, This measure is about the right to know — disclosure of critical information about the most widely consumed products. Consumers demand disclosure and truth-telling about food, and they’re right.”

The bills would require labels for bioengineered foods intended for human consumption, including whole foods, processed foods, seafood and animal-based foods. Manufacturers of a bioengineered food would have to declare the fact in the food’s ingredients label. Also, any product that has been bioengineered would not be allowed to identify itself with a “natural” claim.

The bills would exempt from their labeling requirements food served in restaurants or similar eating establishments, medical food, food (meat) produced using a bioengineered vaccine, and a food or processed food whose manufacture included the use of a bioengineered processing aid (including yeast) or enzyme.

Ms. Boxer and Mr. DeFazio said the legislation also would resolve concerns about the emerging patchwork of state labeling standards by directing the F.D.A. to implement a federal labeling standard for all bioengineered foods. They noted three states — Connecticut, Maine and Vermont — have mandatory bioengineered food labeling laws, and in 2013 and 2014, more than 60 bills and ballot initiatives requiring labeling were introduced in more than 30 states.

Thirteen other senators, all Democrats, joined Ms. Boxer in sponsoring the Senate bill, S. 511. Twenty-two other representatives, 21 Democrats and 1 Republican, joined Mr. DeFazio in sponsoring the House bill, H.R. 913.

At the press briefing, Ms. Boxer and Mr. DeFazio released a list of more than 120 businesses and farm and consumer advocate organizations that support the bills.

Most major food companies and food industry associations favored a different legislative response to actions in several states aimed at requiring labeling of bioengineered foods. They supported the Safe and Accurate Food Labeling Act, which was introduced last year by Representative Mike Pompeo of Kansas. It was expected that Mr. Pompeo will reintroduce that bill or similar legislation in the 114th Congress.

The centerpiece of Mr. Pompeo’s bill was a mandatory premarket biotechnology notification program, which would have required food manufacturers to notify the F.D.A. at least 210 days before a bioengineered organism or ingredient was to be released into interstate commerce. The F.D.A., in turn, would be required to respond promptly to such a notification by stating whether the agency accepted or rejected the submitting company’s assertion that the bioengineered organism was safe for use by humans or other animals.

The Safe and Accurate Food Labeling Act would have preempted labeling measures approved in the various states.

With regard to labeling, Mr. Pompeo’s bill would require labeling of a bioengineered food or food ingredient only if the F.D.A. determined that there “is a material difference between a food produced from, containing or consisting of a bioengineered organism and its comparable marketed food and that disclosure of such difference is necessary to protect health and safety or prevent the label or labeling of such from food from being false or misleading.” Only in that instance would the F.D.A. be required to specify labeling “that would adequately inform consumers of such material difference.” The bill added, “The use of biotechnology does not, by itself, constitute a material difference.”

With that exception, labeling of bioengineered foods would remain voluntary under the Pompeo bill.

To that point, the F.D.A. itself stands by its longstanding determination that bioengineered foods introduced thus far do not differ “materially” from foods manufactured by means of more traditional technologies.