The U.S. Food and Drug Administration is banning artificial trans fat from the food supply, a step expected to reduce heart disease and prevent thousands of fatal heart attacks each year.

Two years ago, the FDA made a preliminary determination that partially hydrogenated oils, found in many processed foods, were no longer “generally recognized as safe.” The FDA is now finalizing that action, saying that partially hydrogenated oils are not generally recognized as safe for any use in human food. Manufacturers have three years to phase out the use of the oils.

“We made this determination based on the available scientific evidence and the findings of expert panels,” says Susan Mayne, director of FDA’s Center for Food Safety and Applied Nutrition.

Partially hydrogenated oils are the primary source of industrially produced trans fat. The oils have been widely used since the 1950s to extend the shelf life of processed foods. But studies have consistently linked trans fat consumption to heart disease.