Communities across the United States are examining the manufacture, use, transport, and storage of hydrogen fluoride (HF) near residential areas as a consequence of a major release of HF in Texas in 1987. Reference exposure levels for routine and accidental HF emissions are calculated using existing animal and human data. The approach employs a logprobit extrapolation of concentration‐response data to the 95 lower confidence limit on the toxic concentration producing a “benchmark dose” of 1 response (TC01), called a practical threshold. Species‐specific and chemical‐specific adjustment factors are applied to develop exposure levels applicable to the general public. Using this method, the 1‐hr reference exposure level to protect the public against any irritation from a routine emission (REL‐1) is 0.7 ppm and the level to protect against severe irritation from a once‐in‐a‐lifetime (REL‐2) release is 2 ppm. This approach is compared to a modified “uncer
展开▼
