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Page last reviewed: 11/22/2006
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Isocyanates

Isocyanates are compounds containing the isocyanate group (-NCO). They react with compounds containing alcohol (hydroxyl) groups to produce polyurethane polymers, which are components of polyurethane foams, thermoplastic elastomers, spandex fibers, and polyurethane paints. Isocyanates are the raw materials that make up all polyurethane products. Jobs that may involve exposure to isocyanates include painting, foam-blowing, and the manufacture of many Polyurethane products, such as chemicals, polyurethane foam, insulation materials, surface coatings, car seats, furniture, foam mattresses, under-carpet padding, packaging materials, shoes, laminated fabrics, polyurethane rubber, and adhesives, and during the thermal degredation of polyurethane products. Health effects of isocyanate exposure include irritation of skin and mucous membranes, chest tightness, and difficult breathing. Isocyanates include compounds classified as potential human carcinogens and known to cause cancer in animals. The main effects of hazardous exposures are occupational asthma and other lung problems, as well as irritation of the eyes, nose, throat, and skin.

Isocyanates hazards are addressed in specific standards for the general industry, shipyard employment, and the construction industry.

OSHA Standards

This section highlights OSHA standards, preambles to final rules (background to final rules), and standard interpretations (official letters of interpretation of the standards) related to isocyanates.

Note: 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 Employment (29 CFR 1915)

Construction Industry (29 CFR 1926)

  • 1926 Subpart D, Occupational health and environmental controls
    • 1926.55, Gases, vapors, fumes, dusts, and mists
    • 1926.64, Process safety management of highly hazardous chemicals
      • Appendix A, List of highly hazardous chemicals, toxics and reactives (Mandatory)

Preambles to Final Rules

Standard Interpretations

Hazards and Solutions

Many workers are unaware of the potential hazards that chemicals present in their work environment, which makes them more vulnerable to injury. The following references aid in recognizing and evaluating hazards associated with isocyanates in the workplace.

  • Right to Know Hazardous Substance Fact Sheets. New Jersey Department of Health and Senior Services. These fact sheets include 1,055 individual hazardous chemicals with information about acute and chronic health hazards. At least 100 fact sheets are revised every year and 235 have been translated into Spanish. The following fact sheets cover isocyanate compounds.
  • OSHA Technical Manual (OTM). OSHA Directive TED 01-00-015 [TED 1-0.15A], (1999, January 20).
  • Chemical Hazard Communication. OSHA Publication 3084, (1998). Also available as a 248 KB PDF, 31 pages. Addresses the need for chemical hazard communication and explains why a standard is necessary to minimize workplace hazards.

  • Evaluation of the Effectiveness of Air-Purifying Respirator Cartridges in Removing MDI Aerosols from Air. The Dow Chemical Company, (1997). Shows that organic vapor cartridges without a particulate filter were not effective at removing Methylene bisphenyl isocyanate (MDI) aerosols from air, while organic vapor cartridges with dust/mist (DM) or high efficiency (HEPA) filters effectively removed greater than 99 percent of MDI aerosol and vapor in all test atmospheres.

  • Preventing Asthma and Death from Diisocyanate Exposure. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 96-111, (1996). Discusses the recognition, evaluation, and control of diisocyanate exposures.

  • Documentation for Immediately Dangerous to life or Health Concentrations (IDLHs). National Institute for Occupational Safety and Health (NIOSH) Chemical Listing and Documentation of Revised IDLH Values, (1994, March).
  • The Environmental Protection Agency (EPA) has prepared four Health Effects Fact Sheets for specific isocyanates.
  • The following studies indicate that respiratory sensitivity to isocyanates may be related to previous dermal exposure.
    • Kimber, I. "The Role of the Skin in Development of Chemical Respiratory Hypersensitivity." Toxicology Letters 86(1996): 89-92.
    • Bickis, U., and  K. Nakatsu. "A Single Skin Contact with Toluene Diisocyanate (TDI) Causes a One-Year Persistence of Airway Sensitization, Demonstrable in Vivo and in Vitro." (1996). Abstract of platform presentation No. 310 presented at the 1996 American Industrial Hygiene Conference and Exposition.
    • Bickis, U. "Investigation of Dermally Induced Airway Hyperreactivity to Toluene Diisocyanate in Guinea Pigs." Ph.D. thesis, Department of Pharmacology and Toxicology, Queen’s University, Kingston, Canada, (1994).
    • Karol, M. H., et al. "Dermal Contact With Toluene Diisocyanate (TDI) Produced Respiratory Tract Hypersensitivity in Guinea Pigs." Toxicol. Appl. Pharmacol 58(1981): 221-230.
    • Rattray, N. J., et al. "Induction of Respiratory Hypersensitivity to Diphenylmethane-4,4’-Diisocyanate (MDI) in Guinea Pigs; Influence of route of exposure." Toxicology 88(1994): 15-30.
    • Deschamps, F., et al. "Mechanisms of Occupational Asthma Induced by Isocyanate." Ann. Occup. Hyg. 42(1998): 33-36.
    • Cole, K. C., et al. "Flexible Polyurethane Foam. I. FTIR Analysis of Residual Isocyanate." Applied Polymer Science 34(1987): 395-407.

Possible Solutions for Workplace Hazards

Sampling and Analysis

Additional Information

Related Safety and Health Topics Pages

Training

  • Isocyanates in Paints [193 KB PDF, 1 page]. Workplace Safety and Health Division of the Manitoba Labour and Immigration, Bulletin 143, (2008, December). Includes a short summary of hazards and protective measures for workers spraying isocyanate-containing paints.

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