Isocyanate-Based Paints-May 2013

Monthly Round Up of Important Ideas and Standards in
Industrial Hygiene and Safety 

May 2013

IN THIS ISSUE: Isocyanate-Based Paints

Modern paints often come in two parts: the paint and the hardener. Isocyanates are used in these paints to create a unique chemical bond that sets it apart from other coatings. When mixed, a odorless and invisible material is produced creating more durable and high gloss coatings with great aesthetic properties that cure quickly. Although the quantity of isocyanate generated may be small, over time, it may still be harmful to employees.

Isocyanates may sensitize workers after contact, and if repeated, even at concentrations below occupational standards,   employees can become susceptible to respiratory irritation, bronchitis, and severe asthma attacks. According to NIOSH, “death from severe asthma attacks in sensitized subjects has been reported.” The major route of occupational exposure is inhalation of the vapor or aerosol although exposure may also occur through skin contact during mixing or painting.  Workers may also be exposed to other isocyanate-containing products such as polyurethane foam.

There is no safe level of exposure for a person sensitized to isocyanate. The objective should be keep exposure as low as possible. A number of steps may be taken to control the hazard:

  • Substitute a less hazardous material when feasible.
  • Install and maintain engineering controls such as closed systems and ventilation minimizing Isocyanate exposure. Exhaust ventilation systems should be designed to capture and contain vapors and particulates.
  • Install ventilation in paint mixing rooms. The pickup vent should be located low in the room, since Isocyanate vapors are heavier than air.
  • Require the use of appropriate personal protective clothing and equipment such as coveralls, footwear, chemical-resistant gloves and goggles, full face shields, and suitable respiratory equipment.
  • Only the most protective respirators, such as airline respirators or SCBA, should be used, although not as the primary control for routine operations.
  • Educate employees on the hazards of isocyanate exposure and how to use the controls that are in place.
  • Conduct periodic medical monitoring of exposed employees under the direction of a physician.
  • Conduct periodic air sampling to ensure that employee exposure is low as feasible.

Isocyanate-based paints are used in many coating applications and they are probably here to stay. Since Isocyanates are sensitizers with potentially severe effects, employers should provide the best controls, personal protective equipment, training, and monitoring available. For more information on this topic and to discuss your company’s safety and industrial hygiene needs call OccuSafe at (214) 662-6005 or contact us at

OccuSafe Industrial Hygiene & Safety, Inc. provides skills and expertise to recognize, evaluate and control hazards and injuries in the areas of industrial hygiene, occupational safety and health.   OccuSafe services companies of all sizes in a range of industries.

This newsletter is published monthly by OccuSafe Industrial Hygiene & Safety Services, Inc. Feel free to forward it to friends and colleagues. 

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