By demonstrating the impact of atmospheric emissions from municipal waste incinerators on the risk of certain cancers between 1990 and 1999, this study confirms the effectiveness of the measures to reduce pollutant emissions that have been imposed on these industrial facilities since the late 1990s. We can therefore expect a decrease in cancer risk among populations exposed to current emission levels. However, given the uncertainty regarding the latency periods for cancer onset, we cannot rule out the possibility that past exposures dating back to the 1970s may still contribute to the development of cancer today. (R.A.)