A peer-reviewed study has determined that the amount of chlorinated wastes burned in a combustor is not related to dioxin emissions from these facilities. While the waste burned in each of these facilities contained various levels of chlorinated products, the amount of dioxin these facilities emitted was found to be unrelated to the amount of chlorine products in the waste stream. A wide range of chlorinated wastes were burned in these facilities, and chlorine content in the waste stream ranged from 0.1 percent to 80 percent. These factors include air pollution control system temperature, fly ash chemistry and combustion conditions, among others. A variety of factors are thought to contribute to dioxin formation in flue gases.
Many scientists believe dioxin is formed through a catalyzed reaction on fly ash surfaces.
In this hypothesis, specific sites must be activated in order for dioxin to be produced, and activating more sites increases dioxin levels. But since the number of active sites is limited on the fly ash, the pathways for these reactions are soon in full use, so the formation of dioxin is limited regardless of how much chlorine is present. This catalyzed reaction concept explains why the amount of chlorine in does not correlate to the amount of dioxin out. When the pathways are full, dioxin production reaches its peak, and the rate of production remains the same, despite the fact that the amount of available chlorine in the combustor gases may increase. The ASME study uncovered some other factors that affect dioxin output.