[Investigation and analysis of the etiology of suspected occupational asthma caused by toluene diisocyanate].

Objective: To conduct an occupational hygiene investigation and simulated sampling and testing on welding positions in a company in a certain province, and to perform a simulated analysis of the concentration of occupational hazard factors in workers suspected of occupational asthma. Methods: In November 2023, the investigation and analysis of workers' exposure to occupational hazard factors were carried out through occupational hygiene surveys, laboratory simulated sampling and testing, and a combination of qualitative and quantitative detection methods. Results: Toluene diisocyanate (TDI) was present in the workplace air of the employer. TDI was detected in the raw materials provided by the workers. Laboratory simulations of the production process and working conditions at the position were conducted with sampling at different distances, revealing a maximum TDI concentration of 0.49 mg/m(3) and a minimum concentration of 0.01 mg/m(3). The results showed that the closer the sampling distance was to the breathing zone, the more significantly the TDI concentration increased. The laboratory simulated sampling and testing results were highly consistent with the on-site sampling and testing results from a testing agency in Beijing. Conclusion: The occupational hazard factor TDI is present in the workers' workplace, and TDI may be the cause of the suspected occupational asthma in the workers.