Regrettable for whom? GenX chemicals as a case study in detrimental chemical substitution

Numerous examples exist of widely-used chemicals with known or suspected health and environmental risks being replaced with chemicals with uncertain, unknown, or different hazards. This process where one harmful chemical is replaced by another is often referred to as "regrettable substitution," suggesting an unfortunate but unintended outcome. Examining the case of per- and polyfluoroalkyl substances (PFAS) used in fluoropolymer production, we conducted qualitative interviews and content analysis of newspaper articles, lawsuits, regulatory documents, advocacy websites, and chemical industry documents. We identify the structurally produced data gaps that facilitated years of toxic chemical emissions with little regulatory oversight or public knowledge. This harmful chemical substitution process results from structurally produced knowledge gaps related to three main factors: the capitalist growth imperative that incentivizes harmful corporate behavior, statutory limitations and loopholes, and self-imposed regulatory reticence. Rather than being regrettable, we argue that the substitution of GenX for perfluorooctanoic acid (PFOA) is a foreseeable product of structural factors, including corporate influence on science and regulation, that lead to favorable outcomes for industry to the detriment of the broader public. Avoiding this process of detrimental substitution requires vigorous implementation of laws and regulations that ensure greater transparency, accountability, and prioritization of public health.