Incidence of Occupational Asthma and Exposure to Toluene Diisocyanate in the United States Toluene Diisocyanate Production Industry

J Occup Environ Med. 2017 Dec;59 Suppl 12(Suppl 12):S22-S27. doi: 10.1097/JOM.0000000000000890.


Objective: This study examines asthma risk in facilities producing toluene diisocyanate (TDI).

Methods: A total of 197 workers were monitored from 2007 to 2012. TDI air concentrations were used to estimate exposures.

Results: The incidence of cases consistent with TDI-induced asthma was 0.009 per person-years (seven cases) or consistent with TDI-induced asthma or asthma indeterminate regarding work-relatedness was 0.012 (nine cases). Increased risk of cases consistent with TDI asthma was observed for cumulative (odds ratio [OR] = 2.08, 95% confidence interval [CI] 1.07 to 4.05) per logarithm parts per billion-years and peak TDI exposures (OR = 1.18, 95% CI 1.06 to 1.32) (logarithm parts per billion). There was a weak association with cumulative and peak exposures for decline of short-term forced expiratory volume in one second (FEV1). Asthma symptoms were associated with workers noticing an odor of TDI (OR 6.02; 95% CI 1.36 to 26.68).

Conclusions: There is evidence that cumulative and peak exposures are associated with TDI-induced asthma.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Air Pollutants, Occupational / adverse effects
  • Air Pollutants, Occupational / analysis
  • Asthma, Occupational / chemically induced
  • Asthma, Occupational / epidemiology*
  • Asthma, Occupational / physiopathology
  • Chemical Industry
  • Female
  • Forced Expiratory Volume
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Occupational Exposure / adverse effects*
  • Occupational Exposure / analysis
  • Odds Ratio
  • Odorants
  • Time Factors
  • Toluene 2,4-Diisocyanate / adverse effects*
  • Toluene 2,4-Diisocyanate / analysis
  • United States / epidemiology
  • Young Adult


  • Air Pollutants, Occupational
  • Toluene 2,4-Diisocyanate