In a selected group of detergent industry workers, a close relationship was observed between cutaneous sensitivity and respiratory symptoms from exposure to air borne B. subtilis enzyme containing products. In intracutaneous tests with comparatively high concentrations of two B. subtilis products used commercially, prolonged responses which were generally maximal in diameter at 6 to 8 hours were present at the sites of 75 per cent of 35 “immediate” wheal and flare responses but not at skin test-negative sites. Precipitin reactions with human sera were nonspecific. Antibodies of the IgA and IgM classes were not detectable in the sera of most subjects with the responses observed at 6 to 8 hours. Antibodies of the IgG class were present in most of these sera but were also present in the sera of some subjects with immediate reactions without ensuing responses. Apart from the obligatory preceding “immediate” wheal and flare reaction, responses which evolved over 6 to 8 hours could not be related to any immunologic finding. Evidence is presented which illustrates that reactions observed at 6 to 8 hours did not have a necessary dependence upon the presence of proteinase activity in antigen preparations. Prausnitz-Küstner reactions to B. subtilis antigens and to reagreed antigen E evolved over a period of hours and were similar to gross appearance to those seen in actively sensitized industrial workers. In the discussion, these results are considered in relation to mechanisms underlying prolonged cutaneous allergic responses.