In general, toxic combustion byproducts (TCBs) are the unwanted residues remaining in flue gases, combustion ashes, and wastewaters from the operation of an incineration or combustion facility. The issue of TCBs has been one of the major technical and sociological issues surrounding the implementation of incineration as a waste treatment alternative. Because of the complexity and controversy, EPA's Dr. C.C. Lee in 1989 conceived of and initiated the International Congress on Toxic Combustion Byproducts (ICTCB) to provide a forum for scientists to discuss the issues of controls for TCBS. This Paper focuses on the review of the 1989 ICTCB (the First ICTCB) activities. The objective of these reviews is to discuss: (1) What have we learned from the ICTCB conferences; (2) What can we use from what we have learned; and (3) What improvement in the ICTCBs is needed.