This paper presents the establishment of a parametric model describing the amount of metalcutting fluid departing from the machining area and permeating into the shop floor environment. The analysis focuses on the process of horizontal turning with overhead fluid jet application. The portion of fluid that leaves the machining area and does not land on the fluid pen is considered as the permeating cutting fluid that contributes to environmental contamination. The quantitative model developed in this analysis accounts for three primary mechanisms of which metalworking fluid enters into and endangers the shop floor environment. The three primary mechanisms are the evaporation of fluid resulting from high temperature in the cutting zone, spin-off of fluid from the workpiece due to rotational motion and the splash due to kinetic energy from fluid-workpiece impact. Process parameters and fluid properties found to affect these mechanisms include part diameter, rotation speed, fluid velocity, fluid viscosity and tool temperature. The validity of the model has been evaluated experimentally under both conditions of stationary and rotational work-piece.Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Toronto, Ontario, Canada, October 26–28, 1998