Bronchial asthmatic reactivity isocyanate

Persons who have developed a bronchial asthmatic reactivity to one isocyanate may show bronchial asthmatic reactivity to other isocyanates according to studies reported by O Brien et al. (16). 

The mechanism for the development of the bronchial asthmatic reactivity from exposure to isocyanates has not been clearly defined, although there has been and continues to be considerable research on this effect. Bruchner (V7)> Scheel Q8), Nava et. 

The primary respiratory irritancy and bronchial asthmatic reactivity discussed above are generally accepted as occupational health problems that can occur from excessive exposure to isocyanates either as vapor or as inhalable particles in workplace air. 

In summary, the major potential occupational health problem from excessive exposure to isocyanates is primary respiratory irritation. A fraction of workers exposed may develop a bronchial asthmatic reaction to isocyanates and there appears to be some cross reactivity. The most extensive study, including preexposure baseline respiratory function measurements, has provided data indicating that keeping exposures to TDI below 0.02 ppm (0.14 ug/ m3) appears to prevent decrement in respiratory function. There are less data on exposures and respiratory function of workers using other isocyanates. Isocyanates such as MDI are less volatile than TDI. There is less potential for exposure to vapors of the lower volatility isocyanates, but exposures to vapor and to particulates can occur and exposures to all isocyanates do need to be controlled in order to protect workers. 

Munn A (1965) Hazards of isocyanates. Ann Occup Hyg 8 163-169 Newman-Taylor AJ, Davies RJ, Hendrick DJ, Pepys J (1979) Recurrent nocturnal asthmatic reactions to bronchial provocation tests. Clin Allergy 9 213-220 O Brien IM, Harries MG, Burge PS, Pepys J (1979 a) Toluene di-isocyanate-induced asthma. 1 Reactions to TDI, MDI, HDI, and histamine. Chn Allergy 9 1-6 O Brien IM, Newman-Taylor AJ, Burge PS, Harries MG, Fawcett IW, Pepys J (1979b) Toluene di-isocyanate-induced asthma. 2 Inhalation challenge tests and bronchial reactivity studies. Clin Allergy 9 7-15... 

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See also in sourсe #XX -- [ ]

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