[Excerpt] The metalworker can be exposed to cutting oils during application by two basic routes of entry: skin contact and inhalation. The higher risk jobs tend to be those with high cutting speeds, heavy oil flow, and continuous contact, which may result in the worker being splashed with oil on the skin or clothing. The oil may remain on the skin for some time and oil-soaked clothing may be worn all shift.
Cutting oils may be applied manually, by an air-carried mist, or by a continuous flood. When flooding is used, the oil is delivered by a pump, piping, and nozzle to the cutting zone. With this method the tool, work, and chip are flooded. (Used fluid is then collected in the chip pan and returned by gravity to the pump sump.)
Inhalation of cutting oil mists may occur because of the nature of coolant delivery or because of the high temperatures and speeds generated at the cutting tool's working edge. When the mist stream method of coolant delivery is used, much of it evaporates on contact with the hot tool, workpiece or chip. In addition to the intentional production of oil mists, vaporized oil can also be generated by the forces of the rapidly spinning workpiece or tool, or by the vaporization of the fluid from the heat of the cutting process.