These results may have important public health implications, since the general population is also exposed to these viruses. Elevated risks were observed for non-poultry-related occupational exposures such as working in a stockyard, working in a chemical plant, use of chemicals to kill moulds, and working in plants where plastic products were manufactured. These preliminary findings indicate that full scale epidemiological studies of adequate statistical power are needed to examine the role of occupational exposures in cancer occurrence in poultry workers.