FDA has approved the first genetically engineered animal intended for food in the U.S.—an Atlantic salmon that is engineered to grow faster than nonmodified salmon. Produced by Massachusetts-based AquaBounty Technologies under the name AquAdvantage Salmon, the modified fish have been awaiting approval in the U.S. for more than a decade. FDA has determined that all regulatory requirements have been met, “including that food from the fish is safe to eat,” says Bernadette Dunham, director of FDA’s Center for Veterinary Medicine. Environmental groups and some members of Congress are questioning FDA’s decision, saying the agency neglected to address concerns that the engineered salmon could escape and outcompete wild salmon. “The fallout from this decision will have enormous impact on the environment,” says Andrew Kimbrell, executive director of the Center for Food Safety. The advocacy group plans to sue FDA to block the agency’s approval. Dozens of grocery store chains, including Safeway, Kroger, Target, Trader Joe’s, Whole Foods Market, and Aldi, have already said they will not sell the modified salmon.