EPA research on toxics control in wastewater treatment involves three approaches: (1) specific toxics treatability to determine the respective contribution of the three removal mechanisms in conventional wastewater treatment; (2) toxicity detection and reduction in treatment and pretreatment; and (3) innovative concepts to enhance control of toxics in biological treatment. The goal of the treatability research is to develop predictive procedures to estimate the fate of specific toxics in conventional wastewater treatment. Progress in developing the data on the removal mechanisms of partitioning, volatilization and biodegradation is described. Toxicity reduction evaluation (TRE) studies are being used to isolate and trace the causes of toxicity pass-through in treatment, to identify the specific toxics, and to evaluate treatment and pretreatment approaches to reduce toxicity pass-through. Innovative concepts to enhance toxic control include control of the toxic discharge rates into treatment; use of additives such as clays, binding proteins, carbons, enzymes, etc.; use of anaerobic-aerobic treatment combinations, use of bioengineered organisms, and the use of special reactors and operational approaches at central treatment plants to improve toxics removals.