With the state of Vermont on the cusp of passing a bill mandating the labeling of food and beverage products containing bioengineered ingredients, groups are aligning to test the constitutionality of the bill in court.

The Vermont Senate passed the bill, H.B. 112, by a vote of 28 to 2 on April 15, and the state’s House of Representatives passed the bill as amended by the Senate on April 23 by a vote of 114 to 30.

Labeling advocates were ecstatic, but the bill, whose requirements would take effect July 1, 2016, may face legal challenges. The Vermont bill also fueled food industry efforts to secure federal legislation asserting the authority of the U.S. Food and Drug Administration to determine under what conditions bioengineered foods might be required to carry a label and to preempt any labeling laws enacted by individual states.

Mr. Shumlin left no doubt about his intent to sign H.B. 112.

“I am proud of Vermont for being the first state in the nation to ensure that Vermonters will know what is in their food,” the governor said. “The legislature has spoken loud and clear through the passage of this bill. I wholeheartedly agree with them and look forward to signing this bill into law.”

The Vermont legislation was similar to bioengineered foods labeling laws passed in two other northeastern states, Connecticut and Maine, with a critical difference: it contained no “trigger clause.” The Maine and Connecticut laws stated their labeling requirements would not be triggered until specified numbers of neighboring states adopted similar laws. The Vermont legislation contained no such stipulation.

H.B. 112 requires that food produced or manufactured, wholly or in part, via bioengineering and offered for sale in Vermont be labeled.

In the case of a packaged raw agricultural commodity, the manufacturer will be required to label the package offered for retail sale with the clear and conspicuous words “produced with genetic engineering.” In the case of any raw agricultural commodity that is not separately packaged, the retailer shall be required to post a label appearing on the retail store shelf or bin in which the commodity is displayed for sale the words “produced with genetic engineering.”

In the case of any processed food that contains a product or products of bioengineering, the manufacturer shall be required to label the package in which the processed food is offered for sale with the words: “partially produced with genetic engineering,” “may be produced with genetic engineering,” or “produced with genetic engineering.”

H.B. 112 also states a manufacturer of a food produced entirely or in part from bioengineering shall not label the product on the package, in signage, or in advertising as “natural,” “naturally made,” “naturally grown,” “all natural,” or any words of similar import “that would have a tendency to mislead a consumer.”

There were exemptions to the labeling requirements. Food consisting of or derived entirely from an animal that itself was not a product of bioengineering but that may have been fed a food or injected with a drug manufactured via bioengineering will not have to be labeled. Additionally, food served for immediate consumption, including in restaurants, would be exempt.

In anticipation of a challenge to the law in court, H.B. 112 authorized a Genetically Engineered Food Labeling Special Fund to pay costs or liabilities that may be incurred by the state in defending implementation of the legislation. The fund would include bequests, grants or donations of any amount from any public or private sources. Additionally, H.B. 112 directed that “except for those recoveries that by law are appropriated for other uses, up to $1.5 million of settlement monies collected by the Office of the Attorney General” will be made available to the attorney general to defend the law in court should that be necessary.

The Grocery Manufacturers Association in a statement issued April 23 asserted H.B. 112 was “critically flawed and not in the best interests of consumers.” The G.M.A. said the bill sets the nation on a costly and misguided path toward a 50-state patchwork of bioengineering labeling policies that will do nothing to advance the safety of consumers.

“We are currently in the process of evaluating the legislation to determine the best course of action in response to its passage,” the G.M.A. said.

The G.M.A. further stated, “Genetically modified crops are safe and have important benefits for people and our planet. They use less water and fewer pesticides, reduce crop prices by 15% to 30% and can help us feed a growing global population of seven billion people. The Food and Drug Administration, World Health Organization, American Medical Association and U.S. National Academy of Science have all found that foods and beverages that contain G.M. ingredients are safe and materially no different than conventionally produced products. Consumers who prefer to avoid G.M. ingredients have the option to choose from an array of products already in the marketplace labeled ‘certified organic.’

“The government, therefore, has no compelling interest in warning consumers about foods containing genetically modified ingredients, making H.B. 112’s legality suspect at best. As we continue to evaluate the impacts of H.B. 112, we will make a determination about whether litigation is the appropriate response to this misguided legislation.”

In an interview with Vermont Public Radio, in advance of the passage of H.B. 112, Vermont Attorney General Bill Sorrell said, “I’ll be very surprised if we are not sued if the legislature goes ahead and enacts the mandatory G.M.O. labeling statute. A lot of people might not realize that this is arguably a free speech issue.”

Mr. Sorrell said required labeling may be construed as “compelled speech” as the food industry would be required to convey certain information on its labeling. He said should the state be sued over the implementation of H.B. 112, a court would have to decide whether the state’s interest in requiring food manufacturers to advise people whether the products they sell are bioengineered overrides the food industry’s right not to speak through labeling on that issue.