using the same classification system that has been applied to chemicals (Basketter et al., 1994). Formulas that showed statistically significantly less irritation than 20% SDS (based on Fishers exact test analysis of cumulative incidences of positive irritation reactions) were considered non-irritating under these acute exposure conditions. Those statistically
significantly more irritating than (or not statistically different than) 20% SDS were considered irritating. The calculation of a TR50 value for each formulation (Figs. 1B–7B) also facilitated within and cross-study comparisons of irritation potential and enabled the assessment of the consistency of results for similar-type formulations across studies. The profile of responses to the 24 formulations is summarized in Table 3. Except for a seasonal effect ob- served for similar formulations tested under widely dif- ferent seasonal conditions (see below), there was a high degree of consistency in the results obtained for formulations of similar type. All liquid soap/detergent/ shampoo formulas tested in spring/summer/early autumn had very comparable TR50 values. All powder formulas (3 automatic dishwashing and 1 laundry) were non-irritating, although one of the automatic dish detergents was pre-designated a high irritant formula and it had the lowest TR50 value of the four.
The liquid fabric