Virtual Paint Mixing Room

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Hardeners, also called catalysts or activators, contain diisocyanates and organic solvents. Diisocyanates (also called isocyanates) can cause serious health effects at very low levels. Many solvents are also very toxic. Painters should know what chemicals are in the paints they are using, their health effects, and safe handling procedures to protect themselves, their co-workers, and their families.

Hardeners may contain the following diisocyanates:

  • Hexamethylene Diisocyanate (HDI) Polyisocyanate
  • Isophorone (IPDI) Diisocyanate Polyisocyanates
  • Aliphatic Polyisocyanates (generic name)
  • Hexamethylene Diisocyanate (HDI)
  • Isophorone Diisocyanate (IPDI)

    They are reactive chemicals that provide coatings with their quick drying properties and durability. The specific types of isocyanates in refinish hardeners used in your shop can be determined from the supplier MSDS for the hardener.

    Because isocyanates are highly reactive, worker exposure to the lungs, skin, eyes, and nervous system through inhalation, or direct contact, can be quite harmful:

    As a result, in most jurisdictions in Canada, the use of isocyanates is regulated. For example, in Ontario, isocyanates are regulated by Designated Substance - Isocyanates R.R.O. 1990, Reg. 842 (as amended by: O. Reg. 518/92; 108/04). Collision repair facilities are subject to the requirements of this regulation.

    Exposure in paint mixing rooms must be minimized by:

    * Proper local and general ventilation
    * Best working practices, and
    * The use of proper personal equipment.

    For example, proper NIOSH approved respirators as specified by supplier MSDS or local codes or regulations must be used when handling or spraying. Full coveralls must be worn for skin protection, splash proof face shields or goggles to protect eyes, and long-sleeve, impervious gloves (synthetic or natural rubber, PVC, or nitrile are specified) to protect hands.

    More information on the potential effects of isocyanates and safe handling practices can be obtained from the following Canadian sources:


    The isocyanates found in body fillers, base coats and clear coats are polymeric isocyanates. The term isocyanate refers to these and to monomeric isocyanates such as HDI and IPDI,

    Inhalation of mists or vapours containing isocyanates can cause serious health effects. Workers may become sensitized to isocyanates either by breathing in the vapours or through skin contact. Sensitization, after an initial exposure to isocyanates, results in acute allergic reactions to further exposure. Once a person is sensitized, exposure of even very low levels can result in severe breathing difficulties. Apart from sensitization, exposure to isocyanates can also result in irritation of the respiratory tract, skin and eyes and in some cases loss of lung function.

    Workers may be exposed to isocyanates materials when applying isocyanate-based body fillers, base coats and clear coats. Spraying is especially hazardous because the mist produced can easily be inhaled if proper respiratory protection is not worn.

    The isocyanates regulation, Ontario Regulation 455/83, applies to all auto body shops where isocyanate materials are used, the shop is therefore required to have a joint health and safety committee and an isocyanate control program if the assessment discloses that workers' health may be affected by exposure. This hazard alert summarizes the measures and procedures that must be included in the control program.


    1. Employers shall obtain the material safety data sheets from suppliers for all the isocyanate materials used in the shop.

    2. All spraying with materials containing isocyanates shall be done inside a booth designed for paint spraying and equipped with adequate mechanical ventilation. Body filling with materials containing isocyanate should also be done inside the booth whenever practical. If body filling is done outside the booth it should be done in a well-ventilated area. The booth fan should be left running after spraying has ended until all over-spray has been removed. Only this is it safe to remove the respirator.

    3. While spraying, the worker must always wear a NIOSH Type C air line respirator with a full face-piece or hood operated in positive pressure mode or a self-contained breathing apparatus with a full face-piece operated in positive pressure mode. Half-mask air supplied respirators, even if operated in positive pressure mode, organic vapor cartridge respirators and all types of air supplied respirators operated in demand mode do not provide adequate protection and must not be used.

    4. The air supply system must be suitable for supplying breathing air and must provide sufficient capacity to maintain a positive pressure and required flow in each respirator and hood.

    5. Air supplied to respirators must be taken from a clean air area. If there is any doubt regarding the quality of the air, it should be tested. If compressed air is used it must meet the CSA standard for compressed air (CSA Standard Z180.1-M1978)

    6. Isocyanate materials should be handled in a well-ventilated area and the worker shall wear eye protection such as safety glasses, splash goggles, face shield or full-face respirator or hood. Workers must also use gloves and should use coveralls or clothing that helps prevent isocyanate contact with the skin.

    7. If hardener gets in the eyes, flush with clean, lukewarm, low-pressure water for 15 minutes, occasionally lifting the eyelids. Obtain medical attention immediately.

    8. If hardener gets on the skin, wash the affected area with soap and water and, if possible, rub with half-and-half mixture of isopropyl alcohol (rubbing alcohol) and water. Do not use this mixture to flush the eyes! Remove contaminated clothing immediately.

    9. In case of inhalation, move close to a clean air area and obtain medical help immediately.

    10. In case on ingestion, give lots of water or milk. Get medical attention immediately. DO NOT INDUCE VOMITING.

    11. The ventilation equipment such as booth fan and filters shall be maintained and operated in such a manner that the face velocity and ventilation rates in the booth meet booth specifications.

    12. Spills may be neutralized by covering with an absorbent material such as sawdust or vermiculite and soaked for several hours with a mixture of 9 parts water and 1 part isopropyl alcohol. Then disposal can be carried out. Water alone can be used but it takes longer to neutralize the isocyanate.

    13. Do not wear contaminated clothing even if it is dry. Decontaminate clothing by soaking it in a mixture of 9 parts water and 1 part isopropyl alcohol and some liquid detergent. Contaminated equipment, including respirators, should be thoroughly decontaminated with the same mixture. Water alone can be used but it takes longer to neutralize the isocyanates.

    14. All workers working with isocyanate materials should be under the supervision of a doctor who should be familiar with isocyanates. The health of workers must be monitored as indicated in the medical surveillance program specified in the isocyanates regulation.


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    The Virtual Collision / Paint Shop is only a graphic representation of a conceptual service and repair facility. The Virtual Collision / Paint Shop only illustrates subjects which call for environmental program management and not as an illustration of good facility layout and design practices.

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