Isocyanates

Control Measures

Occupational exposure to isocyanates can occur in many industries including motor vehicle repair, printing, furniture manufacture and paint and adhesive manufacture.

As isocyanates are respiratory sensitisers (asthmagens) it is necessary to reduce exposure so far as is reasonably practicable.

If the material you are using contains isocyanates you should first consider if it is possible to complete the task by using products that do not contain isocyanates or have less volatile forms. One method of preventing exposure may involve avoiding unnecessary spraying of products containing isocyanates. Spraying causes more isocyanate to get into the air compared to other methods of application such as using a brush or roller.

Where exposure cannot be avoided it must be adequately controlled.

In some cases control measures may be very straightforward such as ensuring adequate ventilation and airflow which may be sufficient to prevent any build-up of vapours. Other examples may include the use of spray booths or rooms for spraying activities. Engineering controls including spray booths and rooms are referred to as local exhaust ventilation (LEV) systems which are designed to take harmful vapours, aerosols and mists away from a person’s breathing zone.

Where LEV is used, employers should ensure that employees are trained on how to operate the equipment and that it has been suitably maintained and thoroughly examined so as to ensure it is performing as intended. Further information on LEV systems is available within HSE guidance entitled Controlling airborne contaminants at work: A guide to local exhaust ventilation (LEV) HSG258.

Where ventilation systems do not provide enough control, particularly where aerosol may be created in enclosed spaces, respiratory protective equipment (RPE) may also be required. One example of this may be a worker spraying isocyanate based paints in a dedicated spray booth who would also require additional respiratory protection.

Where a respirator is needed:

Ensure the right type of respirator is provided for the task to provide protection against spray mist and vapours. Certain spraying activities may require the use of a higher level of protection e.g. air-fed breathing apparatus.
Workers must have had a face-fit test to ensure tight-fitting respirators fit properly and be clean shaven for this type of respirator to work effectively.
Workers should be trained to use, check and clean the respirator.
The filters or disposable respirators should be changed regularly.
The equipment should be stored in a clean, dust-free place such as a container.
If any defects are found, or the respirator does not fit, is dirty or its filter is old, it should be replaced.

Detailed industry guidance on controlling the risks associated with isocyanates for a range of industries is available at the following links: