Metalworking fluids are used in industrial machining and grinding operations to reduce heat and friction and to remove metal particles. There are numerous formulations, ranging from pure oils (such as petroleum oils) to water-based fluids, including soluble oils and semi-synthetic/synthetic fluids. Metalworking oils can be complex blends of emulsifiers, anti-welding agents, corrosion inhibitors, extreme pressure additives, buffers (alkaline reserve), biocides and other additives.

Yes, it definitely changes. Nitrosamines can form when metalworking oils are stored for long periods of time. Nitrosamines form slowly in water-based oils and can be the result of the interaction of nitrites in the liquid, nitrogen oxides in the lining of the cans used for storage or in the air. Recycling metalworking oils can compound the problem if more reactants are added. The formation of nitrosamines in metalworking fluids is of concern, as many nitrosamines are classified as carcinogens. When using metalworking oils, the primary concern is the presence of contaminants in water-based oils that promote the growth of bacteria and fungi. Bacteria can degrade emulsions and change the properties of oils. While biocides are added to reduce the amount of microbial growth, biocide products themselves have hazardous properties. Other sources of contamination include “stray” oil – oil used to lubricate machinery such as hydraulic oil, gearbox oil and other lubricants. Stray oils leaking into metalworking oils can contribute to microbial growth in many ways, including being a food source for bacteria and creating a variety of conditions for anaerobic microbial growth. Metalworking oils are also contaminated by small particles of metal or alloy objects (e.g. fines, chips, shavings) that are ejected from parts during machining. Common metals include steel or alloys containing nickel, cobalt and chromium. In addition, although the extent of the problem is not clear, there is the potential for oils to heat up directly during use (usually where the cutting tool is working on the metal workpiece) and the temperature may be high enough to cause problems. Metalworking oils can also be contaminated by water, cleaning products used for routine cleaning, or other products at the work site. Improper recycling of materials or the addition of fluids not specified with the lubricant (such as old lubricating oils) will also change the composition of the fluid.

Metalworking fluids can generally contain any number and concentration of hazardous components. The risk of exposure to these chemicals varies depending on the manufacturing process, as well as changes and potential reactions between components, such as refining, recycling, degradation, or use of recovered chemicals. Because there are many types of metalworking lubricants, no matter what type is used, it is best to work safely and keep exposures as low as possible. To do this, you can follow the steps below. Obtain Material Safety Data Sheets (MSDS) from the supplier to find out exactly what type of metalworking lubricant you are working with and what precautions you should take. Obtain technical bulletins that may provide additional health and safety information. Use exposure control measures.

Metalworking oil refers to a range of oils and other fluids used to cool and/or lubricate metal workpieces while they are being machined, ground, milled, etc. Metalworking fluids reduce heat and friction between the cutting tool and the workpiece and help prevent burning and fumes. The use of metalworking fluids also helps to improve the quality of the workpiece by continuously removing fines, chips and shavings from the tool being used and from the surface of the workpiece.