(Created 12/02)
UNL Environmental Health and Safety · (402) 472-4925 · http://ehs.unl.edu
Limitations/Restrictions of Exposure Guideline Use
The exposure guidelines discussed in this part are based on industrial experience, experimental
human studies, experimental animal studies, or a combination of the three. The guidelines were
developed for workers in the industrial environment. Thus, they are not meant to be used for
other purposes. ACGIH in its
Threshold Limit Values and Biological Exposure Indices for 1992-
1993 states:
These limits are intended for use in the practice of industrial hygiene as guidelines or
recommendations in the control of potential health hazards and for no other use, e.g., in the
evaluation or control of community air pollution nuisances, in estimating the toxic potential
of continuous, uninterrupted exposures or other extended work periods, as proof or disproof
of an existing disease or physical condition, or adoption by countries whose working
conditions differ from those in the United States of America and where substances and
processes differ. These limits are not fine lines between safe and dangerous concentration nor
are they a relative index of toxicity, and should not be used by anyone untrained in the
discipline of industrial hygiene.
As can be seen from this qualifier, these exposure limits are not intended as exposure limits for
exposure by the public.
There is the limitation on the use of the exposure guideline as a relative index of toxicity. This is
because the exposure limits are based on different effects for different chemicals. For example,
the TLV-TWA for acetone is chosen to prevent irritation to the eyes and respiratory system. The
TLV- TWA for acrylonitrile is chosen to reduce the risk to cancer. Exposures to these chemicals
at other concentration levels could lead to other effects. Thus, when evaluating the risk of
chemical exposure, all toxicological data should be consulted.
