RESPIRATORY EFFECTS OF A SYNTHETIC METALWORKING FLUID AND ITS COMPONENTS

A synthetic metalworking fluid, MWF ''A'', and its major components we re evaluated using a previously developed mouse bioassay. This fluid a nd its components evoked sensory (S) and pulmonary (P) irritation in m ice. For MWF ''A'' and each of its components, a concentration-respons e relationship was developed on the basis of respiratory frequency (f( R)) responses. From such relationships, the concentration capable of e voking a 50% decrease in mean f(R) was determined for MWF ''A'' and ea ch component (RD(50)). RD(50)S or RD(50)P was used to distinguish decr eases in f(R) that were due to sensory irritation (S) from those due t o pulmonary irritation (P). From RD(50)P values, it was concluded that the fatty acid alkanolamide condensates, tolutriazole, and triazine-t ype biocide components were similar in potency to one another and simi lar in potency to MWF ''A''. By examining potency and fractional compo sition, it was concluded that the fatty acid alkanolamide condensates and the triazine-type biocide largely contributed to the irritancy of MWF ''A''. From RD(50)P values, occupational exposure limits were prop osed for MWF ''A'' and each of its components. The current Threshold L imit Value of 10 mg/m(3) established by the American Conference of Gov ernmental Industrial Hygienists for ''particulates not otherwise class ified'' (PNOC) would be inadequate to protect workers from the irritat ing properties of MWF ''A'' and most of its components.