Published by Oxford University Press doi:10.1093/annhyg/mei016 Commentary Metalworking Fluids—Clearing Away the Mist?

Metalworking fluids (MWFs) are a vital component of a vital process—the machining of metals. They cool and lubricate the metal and tools, carry away waste and swarf and sometimes provide protection against corrosion for the workpiece surface. They have been in use for a century and a half, but the 73 cases of alveolitis and asthma at a British car engine manufacturer in Longbridge, last year, illus-trate that the health risks are still with us (BBC News, 2004). MWFs formulated using vegetable oils have been introduced in the hope of further reducing tox-icity and increasing biodegradability of waste. This issue includes a paper, by a team from the University of Minnesota, looking at the mist generation of some of these formulations (Raynor et al., 2005). The use of MWFs grew with the automobile and aircraft industries. Changes in the composition of fluids have been driven by the need to improve performance as well as reduce hazards. Straight oils became available in the middle of the 19th century. Use of crude synthetics began as early as 1883. Soluble oils (oil and water emulsions) came into use around 1915, semisynthetics (containing a small amount of oil) in 1947 and modern synthetic