Construction hazardous substances: Isocyanates

You can find isocyanates in a number of construction products including polyurethane paints, coatings, foams, glues and flooring. Certain tasks, such as spraying, can produce very high exposure to isocyanates. This page tells you how to control these risks and why.

What you must do

The Control of Substances Hazardous to Health (COSHH) Regulations says you must protect against the risks from isocyanates. Follow the Assess, Control and Review model. Pay particular attention to:


Identify and assess: Identify tasks where you will be using products containing isocyanates. Consider:

Use this information to identify the level of risk. Workers are generally at lower risk of inhaling isocyanates if they are applying the products with hand tools like brushes or trowels. In contrast, spraying is a higher risk task. Seek specialist help if you are unsure.


Where the risks are judged to be low, simple and inexpensive controls will suffice.  For other tasks, like spraying, you will have to do more. The range of isocyanate containing products and the tasks you can use these for mean that you must decide on the specific controls you need based upon your assessment of the risks. Take specialist help if you unsure about this. Give priority to the greatest risks first.

Prevent: Where possible think about eliminating or reducing isocyanate risks. Consider:

Control: Even if you minimise some of the risk this way, you may still need to control isocyanate risks. Control this by using the appropriate measures below:

Train: Workers need to know how to use the controls properly. They also need to be aware of the signs and symptoms of ill-health from isocyanate exposure.


Supervise: Ensure that controls such as work methods, PPE and welfare are effective and used by the workers.

Monitor: You may need to do health surveillance if there is a reasonable likelihood of getting dermatitis from your work. It could be done by a 'responsible person'. This can be an employee with suitable training. They should:

A competent person should perform annual lung function testing and a questionnaire for asthma if your work involves generating aerosols containing isocyanates.

What you should know

There are a number of different isocyanates. The most common are:

Other types of isocyanates include HDI and IPDI.

Isocyanates can affect your health in a number of ways. They can cause:

Updated 2023-04-25