Comparison of two-phase decontamination sequences after hydrofluoric acid exposure: Evidence from a viable human skin model

Background Exposure to hydrofluoric acid (HF) can cause systemic poisoning due to transdermal fluoride penetration (TFP). Therefore, accidents involving HF demand immediate first-aid measures. We investigated different skin-decontamination sequences and their impact on TFP in an ex-vivo human skin model. Methods Viable human skin was exposed to 30% HF for 1 min in a static diffusion-cell model, and TFP was observed for 72 h. We compared the efficiency of different decontamination sequences, consisting of a first acute decontamination phase and a second subacute decontamination phase, using various acute and subacute decontamination agents at different skin temperatures (26°C and 32°C). Results Despite quick decontamination, significant fluoride penetration was observed within the first hours of exposure across all decontamination scenarios. Acute phase: The choice of decontamination agent had minimal effect on TFP, while reducing the skin temperature from ∼32°C to ∼26°C significantly decreased fluoride absorption. Subacute phase: Decontamination with a calcium gluconate gel, with or without HEPES, significantly reduced TFP by 25% and 28%, respectively (at 32°C), compared to no additional intervention. The combination of calcium gluconate–HEPES gel and reduced skin temperature achieved a significant 52% reduction in TFP at 72 h compared to no subacute decontamination at 32°C (when primary decontamination was kept identical). Conclusion The findings from our ex-vivo experiments indicate that removal of HF by any possible means is vital in the acute phase, and that subsequent gel decontamination during the subacute phase may offer an additional benefit by reducing systemic absorption from the intradermal fluoride depot.