On April 22, 2026, the U.S. Food and Drug Administration announced a long-overdue update to its list of harmful and potentially harmful constituents (HPHCs). This marks a step in the right direction, one that will help the agency be able to use the latest evidence in assessing tobacco products for commercial sale. Still, it remains to be seen how impactful the update will be.

The Family Smoking Prevention and Tobacco Control Act, passed in 2009, requires that the FDA “establish, and periodically revise as appropriate” a list of HPHCs contained in or produced by use of tobacco products. Among other functions, the list informs the FDA’s scientific evaluation of tobacco products during premarket review. Manufacturers are also required to conduct testing and report all HPHCs found in their products to the agency.

The FDA followed through on its duty to establish this list in 2012, taking comments from the public and recommendations from the Tobacco Product Scientific Advisory Committee before publishing a list of 93 constituents. The list focused on constituents linked to five major health effects of tobacco use: cancer, cardiovascular disease, respiratory effects, reproductive harm, and addiction. When the FDA compiled the original HPHC list, the agency’s authority over tobacco products was limited to cigarettes, cigarette tobacco, roll-your-own tobacco, and smokeless tobacco products. That likely limited the scope of HPHCs that the agency included on the list. The agency later exercised its authority to regulate e-cigarettes and other tobacco products, but it continued to assess them using the original list that emphasized harmful combustion products produced by burning tobacco. Consequently, the FDA was likely evaluating products like e-cigarettes and heated tobacco products without fully accounting for some harmful constituents not captured by the 2012 list.

Appearing to recognize this problem, the FDA issued a notice of its intent to add 19 constituents to the list in 2019. The proposed additions included flavorants, solvents, and byproducts of thermal degradation, and many of them, such as propylene glycol and glycerol, are found in e-cigarette liquids and aerosols. Despite receiving only 40 comments about the proposed new constituents (by comparison, the menthol rule received over 175,000 comments), the FDA did not finalize these additions for years. That delay was notable, especially given that the Tobacco Control Act requires that the FDA periodically revise the HPHC list.

The agency’s recent action is the first revision to the list since 2012. It announced that it finalized 18 additions and is proposing to add 3 further constituents. The finalized additions are acetic acid, acetoin, acetyl propionyl, benzyl acetate, butyraldehyde, diacetyl, diethylene glycol, ethyl acetate, ethylene glycol, furfural, glycerol, glycidol, isoamyl acetate, isobutyl acetate, methyl acetate, n-butanol, propionic acid, and propylene glycol. Most of these are identified as respiratory toxicants, though they also include reproductive or developmental toxicants and carcinogens. The additional 3 constituents that the FDA is considering are pulegone, furfuryl alcohol, and methyl eugenol, and the agency is accepting public comments about those proposed additions until May 26.

Promisingly, this update will help the FDA better account for the harms posed by products like e-cigarettes and heated tobacco products. Yet it is important to note that nothing in the Tobacco Control Act directly requires the FDA to reject a tobacco product application because the product contains or emits HPHCs. Rather, the level of HPHCs in a tobacco product is only one part of the agency’s overall assessment of whether authorizing a product would be “appropriate for the protection of public health.” The FDA’s finalization of 18 additions to the HPHC list is progress, but the agency’s future actions—especially how rigorously it reviews and authorizes products like e-cigarettes—will determine whether this progress translates into meaningful public health gains.

Luke Haqq, Staff Attorney
April 27, 2026