Toluene diisocyanate concentration investigation among TDI-related factories in Taiwan and their relations to the type of industry

Abstract

Objectives: To determine nationwide 2,4 -and 2,6 -toluene diisocyanates ( TDI ) concentrations among polyurethane ( PU ) resin, PU foam, and other TDIrelated industries in Taiwan. The ratios of 2,4 -/ 2,6 -TDI and the noncarcinogenic risk among these three industries were also investigated. Method: Personal and fixed -area monitoring of TDI concentrations as well as questionnaires were performed for 26 factories in Taiwan. The modified OHSA 42 method was applied in sampling and analysis. Noncarcinogenic hazard index was estimated for these three industries based on the average concentration measurements. Results: Significant differences of TDI concentrations were found among the three industry categories. For personal monitoring, PU foam was found to have the highest TDI levels [ 18.6 ( ± 33.6 ) and 22.1 ( ± 42.3 ) ppb for 2,4 -and 2,6 -TDI ], Others average [ 8.3 ( ± 18.9 ) and 10.2 ( ± 17.2 ) ppb ], and PU resin lowest [ 2.0 ( ± 3.5 ) and 0.7 ( ± 1.2 ) ppb ]. The estimated average hazard indices were found to be 310 -3310. Conclusion: A substantial percentage of airborne TDI concentrations among in Taiwan industries exceeded current TDI occupational exposure limit, and significant difference of TDI levels were found among the three industry categories. The control remedy for the tasks of charging and foaming should be enforced with the highest priority. A separate 2,6 -TDI exposure standard is warranted.

Urinary excretion of toluene diisocyanates in rats following dermal exposure

“…The discrepancy between skin exposure application and urinary concentration might be attributed to the greater reactivity of 2,4-TDI, possibly related to higher self-polymerization to form polyurea polymers. The findings of higher reactivity for 2,4-than 2,6-TDI resulting from a faster decay of 2,4-TDI were also consistent with our previous finding (Yeh et al, 2002) and those of others (Rando et al, 1984, Lind et al, 1996. Bello and colleagues (2006) exposed hairless guinea pig skin in vitro to several isocyanate compounds including octyl isocyanate, polymeric hexamethylene diisocyanate (pHDI), polymeric isophorone diisocyanate isocyanurate (pIPDI) and methylenediphenyl diisocyanate (MDI) using attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR) to measure the absorbance decrease on skin over 60 min.…”

“…On the other hand, in the human field observation study performed by Liu and colleagues (2000), they concluded that skin exposure to isocyanates in the workplace could be very common by using calorimetric skin pads to evaluate HDI exposure. Our previous field investigations on TDI-related industries in a nationwide surveillance found the workers in the manufacturing processes could be easily exposed to TDI via skin contact (Yeh et al, 2002). Up to the present, no absorption and elimination information on kinetics regarding dermal exposure to TDI have ever been presented in the literature.…”

“…Most of the TDI commercial forms in industry are a mixture of 80%:20% (w:w) 2,4-and 2,6-TDI (Timchalk et al, 1994;Yeh et al, 2002). Five to ten percent of the workers exposed to TDI will suffer from occupational asthma, which makes TDIs the leading cause (Baur, 1996;Bernstein, 1996;Deschamps et al, 1998;Mapp et al, 1988;Ott et al, 2003;Wang et al, 1998).…”

UHPLC-MS/MS Method for the Analysis of 2,6 Toluene Diisocyanate and 2,4 Toluene Diisocyanate Released from Microa-gglomerated Corks in Wine

“…Several methods for the analysis of 2,4-TDI and 2,6-TDI have been reported in literature to detect the levels in air or in material which can release these compounds in the environment. Most of them uses liquid chromatography UVQDa or MS/MS technique after derivatization (Donchenko et al 2020;Gagné et al 2003); others used HPLC-FL (Yeh et al 2002), or gas chromatography coupled with flame ionization detector (FID) or electron capture detector (ECD) (Yun et al 2006).…”