Respiratory diseases caused by occupational exposure to 1,5-naphthalene-diisocyanate (NDI): Results of workplace-related challenge tests and antibody analyses.

BACKGROUND: 1,5-naphthalene-diisocyanate (NDI) is an aromatic diisocyanate with a very low vapor pressure which is mainly used in the automotive industry.
METHODS: In the present study we described five cases with workplace-related asthma and one case with extrinsic allergic alveolitis associated with pulmonary hemorrhage after NDI exposure.
RESULTS: Corresponding to case histories, extrinsic alveolitis on asthmatic reactions in three subjects and a rhinitis reaction in one patient could be reproduced by inhalative challenge tests to NDI at a concentration of 10 ppb. Preliminary IgE and IgG antibody analyses in patients' sera did not produce significantly positive results.
CONCLUSIONS: According to the outcome of our tests and in comparison with several other studies, we conclude that NDI should be classified as potent airway-sensitizing substance. Improved workplace conditions and decrease in threshold limit values should therefore be recommended.