Prevention Guidance for Isocyanate-Induced Asthma Using Occupational Surveillance Data

BACKGROUND:  Data from Washington State’s work-related asthma surveillance system were used to characterize isocyanate-induced asthma cases occurring from 1999 through 2010.

METHODS:  Injured worker interviews and medical records were used to describe the industry, job title, work process, workers’ compensation cost and exposure trends associated with 27 cases of isocyanate-induced asthma.

RESULTS:  

The majority (81%) of cases were classified within the surveillance system as new-onset asthma while 19% were classified as work-aggravated asthma. The workers’ compensation cost for isocyanate-induced asthma cases was $1.7 million; this was 14% of the total claims cost for all claims in the asthma surveillance system. The majority of cases (48%) occurred from paint processes, followed by foam application or foam manufacturing (22%).  Nine of the asthma cases associated with spray application occurred during application to large or awkward-shaped objects.  Six workers who did not directly handle isocyanates (indirect exposure) developed new-onset asthma. Two cases suggest that skin contact and processes secondary to the isocyanate spray application, such as clean-up, contributed to immune sensitization.

CONCLUSIONS:  

Surveillance data provides insight for the prevention of isocyanate-induced respiratory disease.  Key observations are made regarding the development of work-related asthma in association with a) paint application on large objects difficult to ventilate, b) indirect exposure to isocyanates, c) exposure during secondary or clean-up processes, and d) reports of dermal exposure.