Cross-Sectional Survey of Workers Exposed to Aliphatic Diisocyanates Using Detailed Respiratory Medical History and Questions Regarding Accidental Skin and Respiratory Exposures

Abstract

Consistent with a previous study, no cases of occupational asthma were identified from exposure to 1,6-hexamethylene diisocyanate, isophorone diisocyanate, methylene bis(4-cyclohexyl isocyanate), or their polyisocyanates even though many employees reported detection of odors (93%) or skin exposures (53%).

Is Isocyanate Exposure and Occupational Asthma Still a Major Occupational Health Concern? Systematic Literature Review

“…In two studies conducted in companies where air measurements did not show a reading above the exposure limits, no occupational asthma cases were identified after 20 years of retrospective follow-up [16,17]. This finding was confirmed by a shorter inception cohort study (18).…”

“…The risk of occupational asthma would seem to be highest for di-isocyanates (two groups on the same molecule), while the risk is not clearly established for mono-isocyanates [48]. In 2012, a literature review reported that long-term, low-intensity exposures did not appear to be more of a risk for occupational asthma as short, high exposures [49], whereas other studies reported that it is the duration of daily exposure that is predictive for the risk of occupational asthma [17,50]. However, it appears that exposures at undetectable levels may result in pulmonary symptoms such as tightness of the chest [23].…”

“…Six studies reported results for chemical industry employees: five cohort studies and one case series, covering the period from 1999 to 2017 (Table 2). TDI and HDI are the main isocyanates used in this industry [14][15][16][17][18][19].…”

“…The proportion of employees with respiratory symptoms suggestive of occupational asthma (without a formal diagnosis) was 15% among exposed individuals, even if the exposure limits were not exceeded. In the absence of biomonitoring, the possibility that the employees were exposed to occasional peaks of isocyanates, without thus causing asthma cannot be excluded [17].…”

Detection techniques for air-borne isocyanates based on fluorescent derivatizing agents

“…[20][21][22][23][24][25][26][27][28][29][30][31][32][33] Due to the severe physiological adverse effect of inhalation of isocyanates, regulatory organizations such as the National Institute for Occupational Safety and Health (NIOSH), Occupational Safety and Health Administration (OSHA) and American Conference of Governmental Industrial Hygienists (ACGIH) have set occupational exposure limits (OELs) for these compounds at 5 ppb (Time-Weighted Average TWA) for a full work shi and 20 ppb (TWA) for a short-range exposure limit. [34][35][36] However, the estimation of isocyanate concentration in the working atmosphere is critical due to its high reactivity, volatile nature and instability. Hence, various research activities have been carried out to develop rapid and sensitive analytical techniques for the detection of airborne organic isocyanates.…”