On Thursday afternoon, the U.S. House of Representatives passed H.R. 1599 which, if enacted into law, would prohibit state and local governments from mandating the labeling of foods made with genetically engineered crops. Significantly, the law would invalidate GMO labeling laws that have already been enacted, although are not yet in effect, in Vermont, Connecticut, and Maine. Vermont’s law is scheduled to go into effect next year, while the laws passed in both Connecticut and Maine include clauses that prevent the laws from being triggered until additional states begin to require similar labeling.

Opponents of the bill object to the limitation that the law would place on states’ rights to regulate the issue – something that states themselves seem to show little consensus on, as it seems for every state that has implemented a GMO-labeling law, there is a state where a similar measure has been voted down. Proponents argue that GMOs have been deemed safe and that mandatory labeling would unnecessarily increase food costs.

The bill would create new, voluntary labels under a National Genetically Engineered Food Certification Program, to be established by the Secretary of Agriculture. It would also allow the Food and Drug Administration (FDA) to require GMO foods to be labeled if “there is a material difference in the functional, nutritional, or compositional characteristics, allergenicity, or other attributes” of the GMO version compared with the “natural” version of the food.

Along these lines, the bill would require FDA to establish regulations that set requirements for foods with labels that contain an express or implied claim that the product is “natural.” FDA has long stated that the agency has “not developed a definition for the use of the term natural or its derivatives,” explaining that “[f]rom a food science perspective, it is difficult to define a food product that is ‘natural’ because the food has probably been processed and is no longer the product of the earth.”

The measure was approved in the House by a vote of 275 to 150, with 45 Democrats voting in favor. Supporters, including many food and agricultural companies, have lobbied fiercely for the bill, which is cited as the Safe and Accurate Food Labeling Act of 2015. Opponents of the bill, who prefer the nickname “Deny Americans the Right to Know,” or DARK Act, are hopeful that it will stall in the Senate.

Last year, over $60 million was spent in lobbying for or against legislation that makes reference to GMO labeling. Such lobbying efforts will undoubtedly kick into an even higher gear as the bill approaches a Senate vote.