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Synthetic Mineral Fibers

Synthetic mineral fibers are fibrous inorganic substances made primarily from rock, clay, slag, or glass. These fibers are classified into three general groups: fiberglass (glass wool and glass filament), mineral wool (rock wool and slag wool), and refractory ceramic fibers (RCF). There are more than 225,000 workers in the US exposed to synthetic mineral fibers in manufacturing and end-use applications.

OSHA Standards

Exposures to synthetic mineral fibers are addressed in specific standards for general industry and shipyard employment. This section highlights OSHA standards and standard interpretations (official letters of interpretation of the standards) related to synthetic mineral fibers. 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)

Shipyard Industry (29 CFR 1915)

Standard Interpretations

Health Effects

There is insufficient evidence that synthetic mineral fibers cause respiratory disease in humans. Results from animal experiments have led to conservative classifications of certain synthetic mineral fibers as possible human carcinogens. Specifically, insulation glass wool, continuous glass filament, rock (stone) wool, and slag wool are not classifiable as to their carcinogenicity to humans. The following resources aid in recognizing synthetic mineral fiber hazards in the workplace.

  • Criteria for a Recommended Standard: Occupational Exposure to Fibrous Glass. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 77-152, (1977, April). Includes health effects, exposures, work practices, sampling, and control information for fibrous glass. Included as an historical reference.

  • Criteria for a Recommended Standard: Occupational Exposure to Refractory Ceramic Fibers. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 2006-123, (2006, May). Describes the potential health effects of occupational exposure to airborne fibers of refactory ceramic fibers.

  • TOXNET for Synthetic Vitreous Fibers. The National Library of Medicine.

  • 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 health hazard due to 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 [43 KB PDF, 11 pages]. World Health Organization (WHO). IARC Classification: Possibly carcinogenic to humans (Group 2B) and Not classifiable as to their carcinogenicity to humans (Group 3).
  • Toxicological Profile for Synthetic Vitreous Fibers. Agency for Toxic Substances and Disease Registry (ATSDR), (2004, September). Includes links to information on health effects, chemical and physical information, potential for human exposure, and more.

  • ToxFAQs™ for Synthetic Vitreous Fibers. Agency for Toxic Substances and Disease Registry (ATSDR), (2004, September). Provides a fact sheet which answers the most frequently asked health questions about synthetic vitreous fibers.

  • Refractory ceramic fibers (CASRN Not found). Environmental Protection Agency (EPA), Integrated Risk Information System (IRIS). Discusses the health effect information for refractory ceramic fibers.

  • Fine Mineral Fibers. Environmental Protection Agency (EPA). Lists fine mineral fibers as a Hazardous Air Pollutant (HAP) under the National Emissions Standard Hazardous Air Pollutants section of its Clean Air Act.

  • Fibrous Glass [358 KB PDF, 6 pages]. New Jersey Department of Health and Senior Services, Hazardous Substance Fact Sheet. Provides a summary source of information of all potential and most severe health hazards that may result from fibrous glass exposure.

  • Marsh, G.M, J.M. Buchanic, and A.O. Youk. "Historical Cohort Study of US Man-Made Vitreous Fiber Production Workers." Journal of Occupational and Environmental Medicine 43.9(2001, September): 803-808. Includes an overview of exposure assessment and exposure-specific job analysis.

  • International Chemical Safety Cards: Glass Wool. National Institute for Occupational Safety and Health (NIOSH), (1997, September 10). Summarizes essential health and safety information on glass wool.

Exposure Evaluation

The following resources aid in evaluating exposures to synthetic mineral fibers in the workplace. Typically, employee exposures are determined from breathing zone air samples that are representative of the 8-hour work day.

  • Chemical Sampling Information. OSHA. Presents, in concise form, data on a large number of chemical substances that may be encountered in industrial hygiene investigations. Basic reference for industrial hygienists engaged in OSHA field activity.
  • Occupational Chemical Database. OSHA maintains this chemical database as a convenient reference for the occupational safety and health community. It compiles information from several government agencies and organizations. This database originally was developed by OSHA in cooperation with EPA.
  • Exposure Limits for Synthetic Mineral Fibers. OSHA shows the time weighted average (TWA) exposure limits for synthetic mineral fibers suggested by OSHA, the American Conference of Governmental Industrial Hygienists (ACGIH), the National Institute of Occupational Safety and Health (NIOSH), the Health and Safety Partnership Program (HSPP), the National Academy of Sciences, and the State of California.

  • Marchant, G.E., et al. "A Synthetic Vitreous Fiber (SVF) Occupational Exposure Database: Implementing the SVF Health and Safety Partnership Program." Applied Occupational and Environmental Hygiene 17.4(2002): 276-285. Describes one element of this Partnership Program, the development of an occupational exposure database that characterizes exposures by fiber type, industry sector, product type, and job description.

Analytical Methods


For additional information, see OSHA's Sampling and Analysis Safety and Health Topics Page.

National Institute for Occupational Safety and Health (NIOSH)

  • Asbestos and Other Fibers by PCM [948 KB PDF, 15 pages]. Method 7400, (1994, August 15). Includes sampling for fibrous glass and refractory ceramic fibers. (Note: Use NIOSH B rules for synthetic mineral fibers.)

  • Particulates Not Otherwise Regulated, Total [186 KB PDF, 3 pages]. Method 0500, (1994, August 15). This method is nonspecific and determines the total dust concentration to which a worker is exposed.

Possible Solutions

Controlling the exposure to synthetic mineral fibers can be done through engineering controls, administrative actions, and personal protective equipment (PPE). Engineering controls include such things as isolating the source and using ventilation systems. Administrative actions include limiting the worker's exposure time and providing showers. Personal protective equipment includes wearing the proper respiratory protection and clothing. The following resources contain information to help control and prevent exposures.

  • NIOSH Pocket Guide to Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 2005-149, (2007, September). Provides a physical description, exposure limits, measurement method, personal protection and sanitation, first aid, respirator recommendations, exposure routes, symptoms, target organs, and cancer sites.
  • Occupational Health Guidelines for Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 81-123, (1981, January). Contains information on identification, physical and chemical properties, health hazards, exposure limits, exposure sources and control methods, monitoring, personal hygiene, storage, spills and leaks, and personal protective equipment.

  • Synthetic Inorganic Fibers [117 KB PDF, 11 pages]. National Aeronautics and Space Administration (NASA), Glenn Research Center, Occupational Health Programs Manual, Chapter 19. Establishes requirements and describes methods for controlling exposures to synthetic mineral fibers.

  • Protect Your Family; Reduce Contamination at Home. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 97-125, (1997). Summarizes a NIOSH study of contamination of workers' homes by hazardous substances transported from the workplace, including fibrous glass. A summary of the Report to Congress is also available.

  • Hazards of fiberglass layup and sprayup [884 KB PDF, 15 pages]. Minnesota Department of Labor and Industry, Occupational Safety and Health Division. Adpated from US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 76-148, (1976). Discusses some recommended work practices, presents case studies from several plants, and provides information on OSHA standards that apply to these industries.

  • Fiberglass Layup and Sprayup. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 76-158, (1976). Contains occupational health and safety information for workers in the reinforced plastics layup and sprayup industry. Identifies common hazards and suggests safe work practices.

Additional Information

Related Safety and Health Topics Pages

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