In an editorial published on March 11, 2016 in the peer-reviewed journal Science, Arlene Blum of the Green Science Policy Institute, Berkeley, U.S., presents her institute’s campaign “Six Classes Challenge.” This offensive aims to promote a 50% decrease in the everyday use of the most hazardous chemicals of concern (COCs) over the next 5 years, and focuses on entire classes of chemicals rather than on individual substances.

Such an approach is expected to prevent so-called “regrettable substitutions” – situations when a banned substance is replaced by its close ‘relative’, which later on is found to possess essentially similar hazardous properties. Such may be the case with perfluorooctanoic acid (PFOA, CAS 335-67-1), also called C8, which has been widely used as a polymerization aid during the production of Teflon. This persistent and highly hazardous substance (FPF reported) is now commonly substituted by e.g. perfluorohexanoic acid compounds (PFHxA or C6). These are faster excreted by humans but still show high persistence in the environment. Moreover, their toxicity is likely to be similar to that of C8 (FPF reported)

The six classes of chemicals of concern outlined by the Green Science Policy Institute are: Highly fluorinated chemicals, antimicrobials, flame retardants, bisphenols and phthalates, organic solvents, and some metals. Of note, many chemicals belonging to these classes are commonly used in food contact materials. The chemical class approach has already been adopted by several large companies, including IKEA and Levi Strauss & Co. Blum hopes that many other companies will soon follow these pioneering initiatives.


Blum, A. (2016). “Tackling toxics.Science 351:1117.