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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 degradation 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.

OSHA Standards

Isocyanates hazards are addressed in specific standards for general industry, shipyard employment, and the construction industry. This section highlights OSHA standards and standard interpretations (official letters of interpretation of the standards) related to isocyanates. 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)


  • newNational Emphasis Program - Occupational Exposure to Isocyanates [322 KB PDF, 48 pages]. OSHA Directive CPL 03-00-017, (June 20, 2013). Describes policies and procedures for implementing a National Emphasis Program to identify and reduce or eliminate the incidence of adverse health effects associated with occupational exposure to isocyanates.

Standard Interpretations

Hazard Recognition

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.

Exposure Evaluation

Analytical Methods


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

National Institute for Occupational Safety and Health (NIOSH)

  • NIOSH Manual of Analytical Methods (NMAM). US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 2003-154, (2003). Provides individual analytical methods, listed by chemical name or method number.


  • U.K. Health and Safety Executive Method 25/2

  • The following are analysis methods for specific isocyanate compounds. It is often desirable to determine the amount of free isocyanate, not just the specific compound. Several methods have been suggested to accomplish this. However, all have had serious problems when applied to field sampling.
    • Streicher, RP, et al. Investigation of the ability of MDHS method 25 to determine urethane-bound isocyanate groups. American Industrial Hygiene Association Journal. 1995;56(5):437-42.
    • Key-Schwartz, RJ. Analytical problems encountered with NIOSH method 5521 for total isocyanates. American Industrial Hygiene Association Journal. 1995;56(5):474-9.
    • Maitre, A., et al. Biological monitoring of occupational exposure to toluene diisocyanate. Int. Arch. Occup. Environ. Health. 1993;65:97-100.
    • Documentation of the threshold limit values and biological exposure indices. American Conference for Government Industrial Hygienists (ACGIH). 1991;6:1581-9.

Possible Solutions

Additional Information

Related Safety and Health Topics Pages


  • Isocyanates in Paints [193 KB PDF, 2 pages]. 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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