Metal Working Fluids-June 2017

Monthly Round Up of Important Ideas and Standards in
Industrial Hygiene and Safety

June 2017

IN THIS ISSUE: Metal Working Fluids

Metal working fluids (MWFs) are used in machining and grinding operations to reduce heat and friction. The health effects of MWFs may include respiratory conditions, skin effects, and an increased risk for some types of cancer.

Composition of MWFs

MWFs are made up of petroleum oils and water-based solutions including soluble oils and synthetic or semi-synthetic fluids. Biocides, corrosion inhibitors, dyes, and other additives may be included in the mixture. Contaminants such as oils, metals, hydraulic oils, and particulates may also be added during use and bacterial growth may add biological byproducts such as endotoxins, exotoxins, and mycotoxins. Workers can be exposed to the fluids by breathing mists generated in the machining process and by skin contact when they handling parts, tools, and equipment.

Health Effects of MWFs
MWFs are known to impact workers’ health.

  • Respiratory conditions include chronic bronchitis, impaired lung function, work related asthma, and  hypersensitivity pneumonitis (HP), an allergic-type reaction in the lungs that may be caused by exposure to certain microbial products. HP, although rare, has been linked to improperly managed fluids.
  • Skin effects of MWFs may include allergic and irritant dermatitis (skin rash).
  • There is also significant evidence that past exposures to some metalworking fluids are associated with increased risk of some types of cancer.

Precautions for MWFs
Although there have been improvements in the management of MWFs, it is not known if these actions have reduced the risk. Despite these effects, OSHA has not developed an exposure standard for MWFs. However, the National Institute of Occupational Safety & Health has set a Recommended Exposure Limit of 0.4 milligrams per cubic meter (mg/m3) respirable exposure and 0.5 mg/m3 for total particulate mass. The following precautions should be implemented:

  • Obtain Safety Data Sheets (SDSs) from the supplier to know recommended precautions .
  • Choose MWFs with the least toxic materials when possible
  • Maintain proper use of biocides.
  • Keep machines clean and change MWFs as necessary.
  • Use properly designed MWF delivery systems, which minimize the amount of fluid mist generated.
  • Some machines require a cooling system for the metalworking fluid. Use cutting machine coolant with a visual coolant filling point and level indicator. The coolant capacity should be suitable for the correct function of the machine tool.
  • Use splash guards to prevent unnecessary spray and splashing.
  • Minimize the number of pipework bends and kinks.
  • Use nozzles that optimize coolant distribution.
  • Use exhaust and local exhaust ventilation to prevent accumulation and recirculation of airborne contaminants.
  • Use proper personal protective equipment (PPE) if engineering controls are not adequate. Employees using PPE must be trained to follow all OSHA PPE requirements.
  • Ensure employees are aware of and promptly report skin or chest symptoms, which may be related to MWFs.
For more information on this topic and to discuss your company’s safety and industrial hygiene needs call OccuSafe at (214) 662-6005 or visit us at

OccuSafe Industrial Hygiene & Safety, Inc. provides skills and expertise to recognize, evaluate and control hazards and injuries in the areas of industrial hygiene, occupational safety and health. OccuSafe services companies of all sizes in a range of industries.

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