To facilitate evaluation of the overall contributions of incinerators to pollutants in the environment, estimates of dispersion of incinerator emissions into the environment should be gathered. The additional information would allow conversion of emissions estimates into environmental concentration estimates.
Government agencies should link emissions and facility-specific data from all incineration facilities to characterize better the contributions of incinerators to environmental concentrations. Existing databases should be linked to provide easy access to specific operating conditions of an incinerator, height and diameter of the emission stack, flow rate and temperature of the gases leaving the stack, local meteorological conditions, air-dispersion coefficients as a function of distance from a facility, and precise geographic location of the emission point. Data should be standardized for uniform reporting.
Few epidemiologic studies have attempted to assess whether adverse health effects have actually occurred near individual incinerators, and most of them have been unable to detect any effects. The studies of which the committee is aware that did report finding health effects had shortcomings and failed to provide convincing evidence. That result is not surprising given the small populations typically available for study and the fact that such effects, if any, might occur only infrequently or take many years to appear. Also, factors such as emissions from other pollution sources and variations in human activity patterns often decrease the likelihood of determining a relationship between small contributions of pollutants from incinerators and observed health effects. Lack of evidence of such relationships might mean that adverse health effects did not occur, but it could also mean that such relationships might not be detectable using available methods and data sources.
Pollutants emitted by incinerators that appear to have the potential to cause the largest health effects are particulate matter, lead, mercury, and dioxins and furans. However, there is wide variation in the contributions that incinerators can make to environmental concentrations of those contaminants. Although emissions from newer, well-run facilities are expected to contribute little to environmental concentrations and to health risks, the same might not be true for some older or poorly run facilities.
Studies of workers at municipal solid-waste incinerators show that workers are at much higher risk for adverse health effects than individual residents in the surrounding area. In the past, incinerator workers have been exposed to high concentrations of dioxins and toxic metals, particularly lead, cadmium, and mercury.