The halogenated solvents, which include vinyl chloride, trichloroethylene,1,2 dichloroethane and chloroform, are a significant source of contamination at Superfund Sites. Among the most important of the halogenated solvents is trichloroethylene (TCE). TCE is a commodity solvent; production levels in the United States alone have been as high as 300,000 tons per year. The pharmacology and toxicology of TCE have been extensively studied. TCE is a carcinogen and a hepatic toxin. TCE is also a ubiquitous environmental contaminant. The primary sources of human exposure to TCE are in the workplace and through contaminated soil, sediment and groundwater, especially near hazardous waste sites. The currently available methods for TCE determination are typically based on gas chromatographic analysis. These methods require dedicated instrumentation and are not readily adapted to field or quick response applications. Enzyme ImmunoAssay (EIA) has repeatedly been demonstrated to have significant advantages over instrument-based methods in terms of simplicity, speed and cost for field, high throughput and/or worksite monitoring. The goal of this program is the development of immunoassays for the environmentally-important and Superfund-critical halogenated solvents. The goal of this project is the development of a TCE bait-and-switch immunoassay which will: (1) be used for hazardous waste site monitoring, and (2) serve as the proof-of-concept prototype for the development of bait-and-switch strategy immunoassays for the halogenated solvent class of environmental contaminants.