FDA announced on June 16, 2015 its final determination that there is no longer a consensus among qualified experts that partially hydrogenated oils (PHOs) are "generally recognized as safe" (GRAS) for any use in human food. In effect, PHOs will now be regulated as food additives, which – unlike GRAS substances – require premarket approval by FDA prior to use in food. FDA has provided a compliance date of June 18, 2018, which means that the food industry will have three years to remove PHOs from food products or seek regulatory clearance for low level uses of PHOs, either through food additive petitions or food contact notifications.
PHOs are the primary dietary source of industrially-produced or artificial trans fatty acids (trans fats). FDA's determination applies specifically to PHOs defined as "those fats and oils that have been hydrogenated, but not to complete or near complete saturation, and with an iodine value (IV) greater than 4." The determination does not apply to ingredients that contain only naturally occurring trans fats, such as those ingredients derived from ruminant sources. The determination also does not apply to the use of conjugated linoleic acid (CLA) or partially hydrogenated methyl ester of rosin as food ingredients, as neither substance fits the definition of a PHO.
FDA announced in November 2013 its tentative determination that PHOs are not GRAS based on the link between trans fats and health risks, as identified by scientific evidence and expert scientific panels, such as the Institute of Medicine (IOM) and the Centers for Disease Control and Prevention (CDC). The Agency received over 6,000 comments (including over 4,500 form letters) on its tentative determination. After considering the comments received, FDA affirmed its earlier conclusion and further stated that the available science does not support the establishment of any "threshold" level below which PHOs may be safely used in the food supply.