ACUTE EFFECTS OF 10-MINUTE EXPOSURE TO HYDROGEN-FLUORIDE IN RATS AND DERIVATION OF A SHORT-TERM EXPOSURE LIMIT FOR HUMANS

A series of acute inhalation exposures of female rats was conducted wi th hydrogen fluoride (HF) to establish a concentration-response curve for nonlethal exposures. Durations of 2 and 10 min were used to simula te possible short-term exposures. Concentrations of HF ranged from 593 to 8621 ppm for a-min exposures and from 135 to 1764 ppm for 10-min e xposures, Additional exposures were performed for 60 min at 20 and 48 ppm HF for comparison to existing Emergency Response Planning Guidelin es. Animals were evaluated on the day after exposure for changes in pa rameters of bronchoalveolar lavage, pulmonary function, hematology, se rum chemistry, body weight, organ weights, and histopathology, Most ex posures were performed with orally cannulated animals to bypass absorp tion of HF in the nose and achieve maximum delivery of HF to the lower airways. One of the primary uses of the resulting data was to estimat e a concentration to which most people could be exposed for 10 min wit hout severe or irreversible health effects, This level was 130 ppm. It was predicted that irritation would occur at this concentration, but the effects on the respiratory tract would not be ''serious'' and woul d be expected to be reversible, The results of this experiment and the subsequent analysis of the data provide an important aid in the plann ing of responses to an accidental release of HF. (C) Academic Press.