In an article published on April 1, 2020 by the Environmental Defense Fund (EDF), authors Tom Neltner and Maricel Maffini discuss new research describing the toxicity of per- and polyfluoroalkyl substance (PFAS) 6:2 fluorotelomer (6:2 FTOH) and the bioaccumulation potential of one of its breakdown products known as 5:3 fluorotelomer carboxylic acid (5:3 acid). The EDF article explains that 6:2 FTOH is commonly used as a starting substance to produce PFAS polymers, which includes many of the liners applied to greaseproof paper and paperboard used as food contact materials (FCMs).

In 2018, scientists at the U.S. Food and Drug Administration (FDA) published findings showing that 5:3 acid was eliminated from the body slowly (FPF reported), and the study, therefore, argued that it could be used as a biomarker for assessing the long-term exposure to 6:2 FTOH. In two recently published studies, the same FDA scientists have confirmed their initial findings and also generated additional evidence showing that (i) the risk posed by the toxicity of 6:2 FTOH may be greater than previously estimated and (ii) that 5:3 acid bioaccumulates and has greater bioaccumulation with lower exposure to 6:2 FTOH. The new research is reported to have been carried out after review of additional data received on both substances as well as a set of additional reports on oral toxicity studies submitted by industry in support of FCM applications. Importantly, the FDA scientists concluded “that 6:2 FTOH is significantly more toxic than [perfluorohexanoic acid] PFHxA” and therefore “the dataset for PFHxA is not appropriate for assessing the potential human health effects associated with 6:2 FTOH exposure.”

EDF argues that these two new studies “highlight weaknesses in the [FDA’s] current chemical safety assessment program,” including that (i) companies are not required to provide new information to the FDA that call into question health risks of food contact chemicals (including their impurities and degradation products), and (ii) there is currently no systematic reassessment of safety decisions once chemical uses are approved. However, the organization sees these two new studies also as a step forward in the FDA’s ongoing re-evaluation of PFAS use in food contact applications (FPF reported). “We look forward to FDA wrapping up its reassessment of the safety of these substances in a transparent manner consistent with its responsibilities.”

Read more

Tom Neltner and Maricel Maffini (April 1, 2020). “FDA scientists push back on an industry-funded analysis about bioaccumulation and toxicity of short-chain PFAS.”


Kabadi, S. et al. (January 7, 2020). “Characterizing biopersistence potential of the metabolite 5:3 fluorotelomer carboxylic acid after repeated oral exposure to the 6:2 fluorotelomer alcohol.” Toxicology and Applied Pharmacology.

Rice, P. et al. (February 19, 2020). “Comparative analysis of the toxicological databases for 6:2 fluorotelomer alcohol (6:2 FTOH) and perfluorohexanoic acid (PFHxA).” Food and Chemical Toxicology.