under the Dangerous Substances Directive of the European Communities (EEC, 1992).
Hence, by definition, any chemical (or formulation) showing equal or greater skin irritation than 20% SDS (by statistical analysis), should be classified as irritating to skin under the acute exposure conditions used. Using the conve- nient calculation of TR50 (time of exposure required for 50% of subjects to show positive skin irritation response), it has been reported that the range of response for 20% SDS across multiple studies is approx- imately 1.5–3 h (Robinson et al., 1998). Testing under