Note that, given the precision of the curve fitting method, all formulations with average TR50 values between 4 and 7 h were essentially equivalent. The powdered formulations (average TR50 values > 16 h) produced few or no skin reactions. The consistent pattern of results obtained, by product class, for these 24 detergent formulations across 7 studies conducted over a 4 year period attest to the utility of this human test method as a suitable and ethical approach for screening the acute irritation potential of these product types. Although conducted on generic prototype formulations, the test results are certainly relevant to marketed formulations within the distinct