Isocyanates Profile

Overview:

Diagnostic information: Exposure to isocyanates may cause chemical bronchitis with initial symptoms of throat irritation, laryngitis, coughing, and chest pain or tightness.1 Asthma (with symptoms of wheezing, coughing, and shortness of breath) may also follow exposure to isocyanates.1 Other effects associated with isocyanate exposure are hypersensitive pneumonitis, chronic pulmonary disease, and contact dermatitis (following direct skin contact).1

Clinical significance: Between 2% and 15% of all asthma associated with industry attributed to occupational exposure to chemicals.2 Quantitative allergen-specific IgE testing offers the capability of monitoring workplace exposure to isocyanates through the measurement of acid isocyanate-specific IgE levels. Increases in acid specific IgE levels are correlated with elevations in exposure.1

Sources of exposure: TDI, MDI, and HDI are three of the most frequently used isocyanates in industry.3 The isocyanates are used primarily as starting materials for a variety of manufacturing processes, including the production of plastics, polyurethane, foams, and electrical wire insulation.1 Isocyanates are also common components of paints and other durable and protective finishes, adhesives, and elastomers in automobile bumpers, printing rolls, and coated fabrics.1 Exposure can occur at any stage from the initial manufacturer of the isocyanates to their final use in various production processes.1 Exposure can also occur from the application of paints and polyurethanes, from the handling and machining of foams, and from the combustion of these materials.1
1. Phillips KK, Peters JM. Isocyanates. In: Sullivan JB, Krieger GR, eds. Hazardous Materials Toxicology, Clinical Principles of Environmental Health. Baltimore, Md: Williams & Wilkins;1992:946-949.

2. Brooks BO, Sullivan JB. Immunotoxicology. In: Sullivan JB, Krieger GR, eds.Hazardous Material Toxicology: Clinical Principles of Environmental Health. Baltimore, Md: Williams & Wilkins;1992:209-210.

3. Montanaro A. Isocyanate asthma. In: Bardana EJ, Montanaro A, O'Hollaren MT, eds. Occupational Asthma. Philadelphia, Pa: Hanley & Belfus Inc;1992:145-147.