Chemical pneumonitis by prolonged hydrogen fluoride inhalation.

Hydrogen Fluoride (HF) inhalation is one of the industrial accidents. It causes serious damage, although it is quickly recognized. Since hydrofluoric acid leaks are under surveillance by the alarm system, and low concentrations of gas also have a distinctive smell, most accidents occur from exposure in a short period to a large amount of HF. Thus, prolonged exposure to HF is exceedingly rare in a developed country. We report seven cases of chemical pneumonitis due to HF inhalation to share clinical course and prognosis.