In a clinical department, personnel and patients complained about irritation of the eyes in connection with cognition disorders and headache. Therefore initiated measurements could demonstrate high values for volatile organic compounds and could identify 2-phenoxyethanol, butoxyethanol, hexanal, and nonanal in the indoor air. Toxicological information on the indoor air contaminants showed, in principle on a qualitative basis, the possibility of such effects; a scientifically derived extrapolation of any induction concentration was not possible. A derivation of health complaints from existing toxicological studies was hampered by missing experiments on inhalation toxicity and the inadequate knowledge on the neurotoxicity of the chemicals concerned; it was also influenced by additive effects of contaminants. In this case, exposed persons reported clear symptoms although only a slightly increased total pollution could be measured and concentrations of merely some pollutants exceeded limits. Based on this situation the authors discussed the need of explicit regulations on indoor immission limits and scientific guidelines for risk evaluation of indoor contaminants to enable consumers to succeed in getting preventive consumer protection. Experts involved in regulatory toxicology should more strongly introduce the precautionary principle when interpreting toxicological animal studies for the definition of indoor contamination limits.
