The U.S. Food and Drug Administration Thursday declared trans fat - found in frozen, fried and other processed foods - to be no longer "generally recognized as safe," marking a move toward banning the substance from restaurants and grocery stores entirely. "While consumption of potentially harmful artificial trans fat has declined over the last two decades in the United States, current intake remains a significant public health concern," said Margaret Hamburg, a commissioner with the FDA, in a statement. "The FDA's action today is an important step toward protecting more Americans from the potential dangers of trans fat. Further reduction in the amount of trans fat in the American diet could prevent an additional 20,000 heart attacks and 7,000 deaths from heart disease each year - a critical step in the protection of Americans' health." The proposal is currently open to public comment for 60 days. Trans fat - the source of which is partially hydrogenated oil - is artificial and was initially considered to be a healthier substitute for saturated fat. Scientific evidence has since proven, however, that there is no safe level of consumption for trans fat at all. In 2006, the FDA began requiring food manufacturers to list trans fat on nutritional labels. In 2007, New York City became the first place to ban trans fat from restaurants.