Can Isocyanates Cause Occupational Asthma?

Occupational asthma is a lung condition induced by chemicals or substances used in the workplace. These chemicals can be paints, glues, pesticides, rubbers, etc. These substances cause inflammation or irritation in the airways resulting in temporary constriction and relaxation of the windpipes. This type of asthma has similar symptoms of other forms of asthma, such as difficulty in breathing, coughing, shortness of breath, and tightness in the chest. It gets better when one is away from the exposure. Thus, the best way to treat occupational asthma is to leave the workplace and avoid exposure to the causative substances.

Can Isocyanates Cause Occupational Asthma?

Occupational asthma is a type of lung disease marked by reversible narrowing of the windpipes due to exposure to a particular substance in the workplace.(1) Isocyanates are the commonest cause of occupational asthma. They are found in 2-pack paints, foams, glues, pesticides, rubbers, and dyes. They usually affect people who are involved in welding, soldering, assembling, molding, core making, printing, and anyone who is working in an occupation where Isocyanates are used.(1)

The conditions at which isocyanates can induce asthma-

  • Isocyanates can cause asthma even if an individual has never experienced it before.
  • An individual may only have asthma attacks when he is exposed to isocyanates.

If the affected person leaves the environment where he is exposed to isocyanate, or if the exposures are controlled satisfactorily, the symptoms of asthma may disappear. If the exposure continues, the affected person may develop regular asthma. He may have asthma attacks even in many environments, triggered by substances other than isocyanates. If it happens, this person has to leave working with isocyanate paints forever.(3)

The Way By Which Isocyanates Induce Asthma: According to an old practice, it was believed that breathing in isocyanates would trigger isocyanate asthma. However, in recent studies, it was found that isocyanate can cause “sensitivity” even through skin exposure in the animals. It is also true for humans. Thus, it is essential not to touch isocyanates to avoid skin exposure. It isn’t very easy because dry paint can also cause sensitivity to isocyanates even the paint is more than a month old.(3)

The Effects Of Isocyanates On The Body: When exposed to isocyanates, they irritate the respiratory tract or the skin similar to other substances do in the body such as acids, dust, ammonia, and solvents. If an individual is a patient of asthma, and he comes in contact with respiratory irritants like isocyanate, then he may have an asthma attack. Even if an individual has asthma, he may develop a cough or a catch in the throat after a day he was exposed, due to these irritants.(3)

Symptoms Of Isocyanate Asthma: Asthma symptoms due to isocyanate involve difficulty in breathing, shortness of breath, coughing, wheezing, and tightness in the chest. Isocyanate asthma is difficult to differentiate from regular asthma until there is a relationship between the attacks, and exposure to isocyanate is explored. During asthma attacks, the body constricts the airways to keep away the isocyanates. It is observed that the asthma attacks can appear in a few minutes of the exposure or four or more hours later, or both.(3)

Diagnosis And Treatment Of Isocyanate Asthma: The diagnosis of Isocyanate induced occupational asthma is similar to other types of asthma. Blood tests, X-rays, pulmonary function tests, allergy, or skin prick tests similar to other forms of asthma. Medications can re-open the airways and help to reverse the attack. But the ultimate solution is to avoid the exposure to get rid of this asthma.(3)


Isocyanates can cause occupational asthma when a person inhales air containing isocyanates or touches the paints containing them. It irritates either respiratory tract or skin, resulting in symptoms of asthma. This type of asthma induce by isocyanate is also called isocyanate asthma.


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