Characteristics of Hazardous Waste - Toxicity

Toxicity Characteristic Leaching Procedure (TCLP) is the test used to determine if wastes exhibit the toxicity characteristic. The TCLP is designed to identify wastes likely to leach hazardous concentrations of particular toxic constituents in simulated landfill conditions. Wastes leaching contaminants above the designated levels exhibit the toxicity characteristic and must be assigned the appropriate EPA hazardous waste number.

Liquid wastes (less than 0.5% filterable solids) exhibit the toxicity characteristic if the waste itself contains contaminants above the designated levels (the TCLP does not need to be performed).

Wastes generated in metals labs and pesticide labs (i.e., excess samples and standards) often exhibit the characteristic of toxicity and thus are hazardous.

The TCLP replaces the Extraction Procedure (EP) Toxicity Test. TCLP is considered more "vigorous" than the EP. Wastes that were previously characterized using the EP should be retested using the TCLP.

§261.24 Toxicity Characteristic