Following allegations of environmental contamination, a scheme for the surveillance of animal health on dairy farms in the vicinity of a large complex of chemical industries in the region of Cork harbour was initiated in 1991. Multidisciplinary investigations were undertaken as a result of unusual incidents of animal ill-health or decreased productivity, and an explosion and fire at one of the industrial plants. There was no evidence that exposure to environmental pollutants caused variations in either productivity or the incidence of disease. Many incidents which might have been linked with environmental pollution were found to have other causes. A broad database of animal disease incidence, productivity and blood composition has been established, and a bank of tissues taken from animals submitted for routine slaughter has been frozen, so that they may be analysed for toxins if required. The main difficulty encountered during the study was inadequate disclosure of information by some herd owners.