Oil is a great catalyst for fire.  Though water soluble metalworking fluids may not have that risk, straight oils are a HIGH risk element for fire.  See the photo on the left.  In SAFETY MONTH we are trying to look at all aspects and risks associated with metalworking fluids.  According to the article:  "Depending on the type of machining, violent reactions of the MWF/oil-air mixture may occur in the interior of the machine tool which can be followed by a fire and severe accidents with burns and high material damages due to fire propagation."  The linked article is from The Fachbereich Holz und Metall.  It is a committee composed of representatives of the German Social Accident Insurance Institutions, federal authorities, social partners, manufacturers and users. It is based on experience gathered by the Expert Committee Woodworking and Metalworking.