Adverse events are localized at the site of application

When inhaled or ingested, QACs interact with cell membranes at the point of contact. Most important, no apparent metabolism or [systemic] distribution is involved in QAC action.

Osimitz TG, W Droege W Adverse Outcome Pathway for Antimicrobial Quaternary Ammonium Compounds. Journal of Toxicology and Environmental Health, Part A 2022 Feb 22;1-17.

Do Quats Get Absorbed?

…Systemic exposure to BAC in antimicrobial soap is very low and below the level of concern identified by the U.S. Food and Drug Administration (500 ng/L) even under maximal use conditions.

• DeLeo PC et al. Systemic Absorption of Benzalkonium Chloride after Maximal Use of a Consumer Antiseptic Wash Product Regulatory Toxicology and Pharmacology. 2021 Jun 23;104978

Human Health Impact Study

• “Quaternary ammonium compounds (Quats) are a large class of … chemicals that are used in a variety of consumer and industrial products for their antimicrobial properties.”
• “[Quats] are poorly absorbed via the oral and dermal exposure routes, are not systemically distributed....”
• “European Chemicals Agency (ECHA) concluded that oral and dermal absorption … is limited, and does not exceed 10%.”
• “..Collectively, available guideline studies indicate that [Quats] are not specific or primary reproductive or developmental toxicants, which is consistent with the conclusions of the Environmental Protection Agency (EPA) (2006a,b) and ECHA (2015a,b).”
• “EPA’s Cancer Assessment Review Committee classified [Quats] as 'not likely to be carcinogenic to humans' and 'Group E – evidence of non-carcinogenicity for humans,' respectively (EPA 2018).”
• “[Biocidal Quats] are not dermal sensitizers, are not specific developmental or reproductive toxicants, are not carcinogenic or genotoxic, and do not cause systemic toxicity.”
• “When conducting their risk assessments for [biocidal quats], EPA (2006a,b) determined that a FQPA [Food Quality Protection Act of 1996] Safety Factor was not needed to protect sensitive human subpopulations (i.e., infants and children) from exposure ….”
• “The EPA’s Hazard and Science Policy Council (HASPOC) reviewed the toxicology database [biocidal quats] and waived the requirements for immunotoxicity and acute and subchronic neurotoxicity testing based on the weight of evidence that strongly suggests that these studies would not result in a lower point of departure for use in risk assessment (EPA 2016a,b).”

Luz, A et al. Human health hazard assessment of quaternary ammonium compounds: Didecyl dimethyl ammonium chloride and alkyl (C12–C16) dimethyl benzyl ammonium chloride Regulatory Toxicology and Pharmacology, Oct, 2020.