[Human biomonitoring after a severe chemical accident--results of a study after the Hoechst AG chemical spill 22 February 1993].

A major industrial chemical accident occurred on 22 February 1993 at Hoechst AG Frankfurt/Germany. Approximately 11.8 tons of a chemical mixture (mostly chlorinated nitroarenes) were emitted, resulting in heavy contamination of Schwanheim, a nearby housing area. Urine samples were collected from the inhabitants of the affected area a few days after the accident and were analyzed for o-nitrophenol (ONP) as a representative metabolite to assess the actual uptake of the pollutants. As a result, ONP was found in urines of control subjects from elsewhere, an observation hitherto not described in the literature. Mean ONP excretion was about three times higher in the Schwanheim population than in the controls. The results show not only a higher accident-related but also a higher permanent ONP-excretion of the population of Schwanheim, pointing to a permanent environmental pollution in Schwanheim. Both results, the hitherto unknown ONP excretion in controls and regional differences in ONP excretion, require further investigation.