Approaches and considerations for setting occupational exposure limits for, sensory irritants: Report of recent symposia

Over the past 50 years significant strides have been made in reducing occup ational exposure to airborne chemicals. To a large extent, the impetus behi nd the reductions has been the identification of presumably safe levels of exposure, or occupational exposure limits (OELs). Most of the reduction in exposure has been to chemicals such as hepatotoxins, neurotoxins, nephrotox ins, and carcinogens that cause frank toxic effects. Recently, however, a n umber of industrial hygiene and occupational medicine initiatives have soug ht to identify acceptable levels of exposure to sensory irritants and reduc e exposure to this class of chemicals. This article presents an overview of the field with emphasis on the work presented at two symposia sponsored by the Chemical Manufacturers Association: "How Do We Set an Occupational Exp osure Limit (OEL) for Irritation?" (1998) at the American Industrial Hygien e Conference and Exposition and "Respiratory Tract Irritation and Olfaction Conference" (1997). The two symposia reviewed clinical and experimental me thods used to assess odor and sensory irritation, to increase understanding of the research needed to establish OELs for sensory irritants, and to dis cuss how to use this information to identify appropriate values. The sympos ia illustrated that research in this area is evolving quickly and that ther e is already sufficient understanding to permit scientists to identify chem icals likely to be sensory irritants. Further, there appears to be an ample number of research methods for identification of airborne concentrations t hat should protect most workers. This article summarizes some of the key po ints raised at these symposia and suggests areas deserving of future study.