The U.S. Food and Drug Administration (FDA) has published a proposed standard of 1 µg/g (dry weight) N-nitrosonornicotine (NNN) in finished smokeless tobacco products. FDA’s rationale for the standard is that NNN is a potent carcinogen, NNN is a major contributor to the elevated cancer risks associated with smokeless tobacco use, and establishing such a limit is appropriate for the protection of public health. However, a public health benefit associated with the proposed NNN limit is not supported by the available scientific evidence, which includes toxicological and epidemiological data, results of quantitative risk assessment (QRA), and modeling projections of population mortality based on potential changes in use behaviors. Specifically, animal experimental designs, including tested exposure concentrations and observed outcomes, are not relevant to humans. Historical levels of NNN in Swedish products used to estimate health risks, and which demonstrate no meaningful risk of oral cancer, were well above the proposed standard. FDA’s QRA approaches do not conform with US Environmental Protection Agency recommendations in risk assessment practice, and results are implied to be representative of oral cancer risk in humans when they are not. Finally, changes in use behaviors likely to be associated with the proposed standard - and the resulting impact on overall population health - are not appropriately considered by FDA. Realistic scenarios for use behaviors likely to result from the proposed standard (e.g. increased use of cigarettes) suggest an increase in mortality that offsets the benefits proposed. Based on an independent evaluation of the epidemiological and toxicological evidence, QRA results, and likely effect on population health, the proposed limit of NNN in smokeless tobacco products would not benefit, or otherwise be protective of, public health.