Consumer groups formally petitioned the U.S. Food and Drug Administration Tuesday to switch gears and evaluate genetically engineered (GE) salmon as a food additive, not a veterinary drug, as the agency has been for several years.

Though the political fight over GE salmon has primarily focused on the potential environmental impact of the technology–a fight fueled by environmental groups and lawmakers with constituent salmon interests–the petition, brought by Consumers Union, Food & Water Watch and the Center for Food Safety is focused primarily on food safety concerns.

Developed by Massachusetts-based AquaBounty Technologies, the engineered AquAdvantage Salmon are essentially Atlantic salmon with an inserted growth gene from a Chinook salmon and an antifreeze gene from an ocean pout. They grow twice as fast as typical Atlantic salmon and require approximately 10 percent less feed to achieve the same weight.

If cleared by FDA, the fish would be the first GE animal approved for human consumption.

“Atlantic salmon is a substance traditionally regarded as safe. [AquaBounty’s] GE process significantly alters the salmon’s composition, however, in a way that is reasonably expected to alter its nutritive value or concentration of constituents, and the new substance raises safety concerns,” reads the petition. “Under the Agency’s regulations and guidelines, such a substance must be treated as a food additive and the Agency must make a closer inquiry into the safety of its consumption, including, but not limited to, subjecting it to extensive pre-market testing.”

The petition also asks that the agency not designate the GE salmon as generally recognized as safe (GRAS). As the petition notes, food additives are presumed to be unsafe, and therefore the company seeking approval for an additive “carries the burden to prove that a food additive is GRAS.

The groups blasted the data supplied by the company to FDA’s Center for Veterinary Medicine and said it “cannot be relied upon to show that AquAdvantage salmon is safe to consume.”

“The data FDA has on GE salmon, which were supplied by Aquabounty, are incomplete, biased, and cannot be relied upon to show that the GE salmon is safe to consume,” said Food & Water Watch executive director Wenonah Hauter. “Aquabounty’s own study showed that GE salmon may contain increased levels of IGF-1, a hormone that helps accelerate the growth of the transgenic fish and is linked to breast, colon, prostate, and lung cancer.”

In the petition, consumer groups warn that the potential health risks of GE salmon are no “different from a number of food additives the FDA has banned in the past, including those that are cancer causing.”

“FDA’s choice to allow the first proposed transgenic animal for food to somehow only be review as a drug is contrary to law, science and common sense,” said George Kimbrell, senior attorney for the Center for Food Safety. “Public health and transparency should be championed, not skirted, particularly when contemplating such an unprecedented approval.”

Aquabounty did not respond to requests for comment on the petition.

The company maintains that the GE salmon are biologically and nutritionally identical to non-GE salmon and pose no threat to human health.