Hydrofluoric acid is a very toxic acid and penetrates the skin and tissues deeply ifnot treated immediately. Injury occurs in two stages; first, by hydration that induces tissuenecrosis and then by penetration of fluoride ions deep into the tissue and by reaction withcalcium. Boric acid and other complexing reagents and appropriate treatment agents should beadministered immediately. Consult appropriate safety literature and have the appropriatetreatment materials readily available prior to working with this acid. See Method 3052 forspecific suggestions for handling hydrofluoric acid from a safety and an instrument standpoint.