back to OSHA Safety and Health Topics

Contents

Page last reviewed: 03/27/2012

Highlights
  • Metalworking Fluids: Safety and Health Best Practices Manual. OSHA. Assists employers in providing a safe and healthful workplace for workers exposed to MWFs through effective prevention programs adapted to the needs and resources of each place of employment.
  • Metalworking Fluids in Small Business: A Health and Safety "QUICKSTART" Guide. OSHA and Independent Lubricant Manufacturers Association (ILMA) Alliance, (2005, December). Provides a step-by-step outline on how to work safely with metalworking fluids (MWFs) and to help small business workers effectively manage the health, safety and environmental impacts of MWFs.
  • Dermal Assessment Guide [5 MB PDF*, 15 pages]. OSHA and Independent Lubricant Manufacturers Association (ILMA) Alliance. Helps small businesses understand the possible connection between instances of employee dermatitis and facility operations that use metal removal fluids.
Metalworking Fluids - Copyright WARNING: Not all materials on this Web site were created by the federal government. Some content — including both images and text — may be the copyrighted property of others and used by the DOL under a license. Such content generally is accompanied by a copyright notice. It is your responsibility to obtain any necessary permission from the owner's of such material prior to making use of it. You may contact the DOL for details on specific content, but we cannot guarantee the copyright status of such items. Please consult the U.S. Copyright Office at the Library of Congress — http://www.copyright.gov — to search for copyrighted materials.
Metalworking Fluids

Metalworking fluids (MWFs) can cause adverse health effects through skin contact with contaminated materials, spray, or mist and through inhalation from breathing MWF mist or aerosol. Millions of workers engaged in the manufacture of automobiles, farm equipment, aircraft, heavy machinery,and other hardware are exposed to machining fluids.

OSHA Standards

Metalworking fluids (MWFs) hazards are addressed in specific standards for general industry, shipyard employment, and the construction industry. This section highlights OSHA standards, Federal Registers (rules, proposed rules, and notices), and standard interpretations (official letters of interpretation of the standards) related to MWFs. Twenty-five states, Puerto Rico and the Virgin Islands have OSHA-approved State Plans and have adopted their own standards and enforcement policies. For the most part, these States adopt standards that are identical to Federal OSHA. However, some States have adopted different standards applicable to this topic or may have different enforcement policies.

General Industry (29 CFR 1910)

  • 1910 Subpart Z, Toxic and hazardous substances [related topic page]
    • 1910.1000, Air contaminants
      • Table Z-1, Limits for air contaminants
        • Oil Mist, mineral: 5 mg/m³
        • Particulates not otherwise regulated, total dust: 15 mg/m³
        • Particulates not otherwise regulated (PNOR), respirable fraction: 5 mg/m³

Shipyard Employment (29 CFR 1915)

  • 1915 Subpart Z, Toxic and hazardous substances
    • 1915.1000, Air contaminants
      • Oil Mist, mineral: 5 mg/m³
      • Particulates not otherwise regulated (PNOR), total dust organic and inorganic: 15 mg/m³

Construction Industry (29 CFR 1926)

  • 1926 Subpart D, Occupational health and environmental controls
    • 1926.55, Gases, vapors, fumes, dusts, and mists
      • Appendix A, Gases, vapors, fumes, dusts, and mists
        • Oil Mist, mineral: 5 mg/m³
        • Particulates not otherwise regulated (PNOR), total dust organic and inorganic: 15 mg/m³

Federal Registers

Standard Interpretations

Health Effects

Metalworking fluids (MWFs) is the name given to a range of oils and other liquids that are used to cool and lubricate metalwork when being machined. MWFs are classified as either "Straight Oil" or "neat" oils (not meant to be diluted with water, and may contain highly refined petroleum, animal, marine, vegetable or synthetic oils); Soluble Oil (highly refined petroleum oils, and emulsifiers); Semi-synthetic fluids; and Synthetic fluids (which may include detergent-like components). The last three classes are diluted with water before use. All MWF classes may contain additives such as stabilizers, biocides, dispersants, dyes, and odorants. When MWFs are used, a primary concern is the presence of contaminants that encourage the growth of bacteria and fungi. Also, there is a potential for oils to be heated high enough where the cutting tool works on metal workpiece to form polynuclear hydrocarbons (PAH's).

While MWFs are used by hundreds of thousands of workers safely, problems can develop when good hygiene practices are not followed or when fluids are not properly managed or maintained. Major health concerns of improperly managed fluids or when good hygiene practices are not followed include skin irritation, allergic contact dermatitis, irritation of the eyes, nose and throat, and, occasionally, breathing difficulties such as bronchitis and asthma. Although rare, some workers have contacted hypersensitivity pneumonitis (HP) from improperly managed fluids. HP is an allergic type reaction in the lungs that may be caused by exposure to certain microbial products. HP is marked by chills, fever, shortness of breath and a deep cough - similar to a cold that will not go away. Prior to 1985, the use of poorly refined mineral oils had been associated with an increase risk of cancers of the larynx, rectum, pancreas, skin, scrotum, and bladder. The following metalworking fluid references provide more hazard identification and health effects.

  • Oil mist (mineral). National Institute for Occupational Safety and Health (NIOSH), (1994, May). Provides an Immediately Dangerous to Life or Health (IDLH) document that includes acute toxicity data for oil mist.

  • Criteria for a Recommended Standard: Occupational Exposure to Metalworking Fluids. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 98-102, (1998, January). Reviews available information about the adverse health effects associated with occupational exposure to metalworking fluids and aerosols.

  • TOXNET for Mineral Oil. The National Library of Medicine Hazardous Substance Database.

  • Report on Carcinogens (RoC). US Department of Health and Human Services (DHHS), National Toxicology Program (NTP). Identifies and discusses agents, substances, mixtures, or exposure circumstances that may pose a hazard to human health by virtue of their carcinogenicity. The listing of substances in the RoC only indicates a potential hazard and does not establish the exposure conditions that would pose cancer risks to individuals.
  • International Agency for Research on Cancer (IARC) Monographs on the Evaluation of Carcinogenic Risks for Humans [1 MB PDF, 454 pages]. World Health Organization, International Agency for Research on Cancer. IARC Classification: Carcinogenic to humans (Group 1).

  • N-Nitroso Compounds in Industry. OSHA Hazard Information Bulletin (HIB), (1990, March 15). Alerts field personnel of the potential for amine compounds, used in many industrial processes, to be nitrosated with nitrogen oxides from the air.

Exposure Evaluation

Basic options to control hazards from metalworking fluids (MWFs) include the following:

  • Obtain Material Safety Data Sheets (MSDSs) from the supplier to know what precautions are recommended.
  • 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 splashguards 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.

The following resources contain information to help evaluate and control MWF exposures. MWF exposures are measured either as mineral oil mist or nuisance dust. Sampling information and appropriate analytical methods include:

Analytical Methods

OSHA

OSHA has developed and validated methods for use by the Salt Lake Technical Center (SLTC) laboratory. The following method has been adopted by many laboratories for the analysis of chemical compounds. Exposures should be evaluated with standard total dust sampling techniques for comparison to the OSHA permissible exposure limits (PEL).

National Institute for Occupational Safety and Health (NIOSH)

Possible Solutions

Additional Information

Related Safety and Health Topics Pages

Other Resources

  • Dermal Assessment Guide [5 MB PDF*, 15 pages]. OSHA and ILMA Alliance. Helps small businesses understand the possible connection between instances of employee dermatitis and facility operations that use metal removal fluids.

Accessibility Assistance: Contact the OSHA Directorate of Technical Support and Emergency Management at (202) 693-2300 for assistance accessing PDF materials.

*These files are provided for downloading.