Epidemiologic research is intended to advance scientific understanding and is one of the possible actions in responding to an episode of industrial contamination. However, it is important to recognize that such studies are not a substitute for public health measures to identify the source of exposure, reduce or eliminate it, and take measures to prevent future events. The merits of initiating an epidemiological study that directly examines the relationship between exposure and disease in the affected population need to be carefully considered. There may be benefits in responding directly to the community’s concerns, providing information to help generate resources to address the problem, and offering an opportunity to learn more about the pollutant health effects. However, there are also costs in the form of financial burdens of the research and prolonged period required to conduct studies, raising unrealistic expectations about what a study will provide, and not utilizing quantitative risk assessment as a more rapid and potentially more informative alternative to a new study. Where data systems are in place, risk assessment combined with health surveillance may often be the most efficient, informative response to the exposure event. New epidemiological studies are most likely to be valuable:

  • when there is little prior knowledge about the pollutant; 
  • when exposure and health outcome can be accurately measured;
  • when there is not strong confounding;
  • when the size of the exposed population is adequate; 
  • when the health consequences of the exposure are observable soon after the exposure occurs.

The balance between costs and benefits of research may vary across settings, depending in part on the economic resources available to pursue new knowledge versus managing a threat to public health and in part on the nature of available environmental health surveillance data collection systems. Before initiating an epidemiological study, it is important to be certain that the goals are attainable for the research and that the research itself will support – rather than interfere with – pursuit of needed public health actions.