Evaluation of Self-Reported Skin Problems Among Workers Exposed to Toluene Diisocyanate (TDI) at a Foam Manufacturing Facility

Abstract

Toluene diisocyanate, or TDI (CAS 584-84-9) is a well-known asthmagen and respiratory irritant. TDI is also known for its ability to irritate the skin and mucous membranes. To further investigate the dermal effects of TDI, NIOSH investigators conducted a cross-sectional study at a flexible foam manufacturing plant. A total of 114 workers participated in the study. Participants completed a medical questionnaire, provided blood for antibody testing to TDI and other allergens, and a subset of participants reporting skin symptoms underwent skin patch testing to a standard diisocyanate panel. Production line workers were more than twice as likely to report skin problems as those working in nonproduction areas (PRR = 2.66; 95% CI = 1.14-16.32; P = 0.02). Age, gender and duration of employment at the plant were comparable among participants working in production and nonproduction areas. Of the 100 participants who provided blood samples for antibody testing, specific IgG antibody to TDI was detected in two individuals, and none of the samples demonstrated specific IgE antibody to TDI. Of the 26 workers who underwent skin patch testing, none developed reactions to the diisocyanate allergens. These results suggest that the skin symptoms among study participants represent an irritant rather than an immunologic reaction to TDI, or to an unidentified allergen present in the foam.

Issues in Diisocyanate Antibody Testing

“…While, in general, 2-3 standard deviations above the control mean has been used in defining a positive response (Cartier et al, 1989;Bernstein et al, 1993;Lushniak et al, 1998;Park et al, 1999;Daftarian et al, 2002), some investigators have utilized OD ratios of 2+ or 3+ calculated in a similar fashion as RAST ratios (Patterson et al, 1987;Grammer et al, 1988;Liss et al, 1988;, and others have used the highest observed control value (Welinder et al, 1988;Skarping et al, 1996;Jakobsson et al, 1997). Available data comparing different criteria for classifying responses as positive or negative are limited, but do indicate that some of the heterogeneity in the prevalence of positive responses to antibody tests across laboratories could be due to differences in classification algorithms.…”

Dermal, inhalation, and internal exposure to 1,6-HDI and its oligomers in car body repair shop workers and industrial spray painters

“…Yet, allergic contact dermatitis as well as skin irritation as a result of dermal exposure have been reported by isocyanate workers. [31][32][33][34][35][36] To summarise, task based external exposure estimates indicate that in car body repair shops and industrial painting companies, mainly (spray) painters are exposed to HDI and its oligomers through inhalation as well as dermal contact. Interpretation of these short term exposure levels with respect to a total internal dose is complicated by large variability in levels within tasks, PPE use, and the lack of knowledge on the relevance of dermal exposure.…”

Risk assessment for consumer exposure to toluene diisocyanate (TDI) derived from polyurethane flexible foam

“…Studies in humans (Daftarian et al, 2002;Huang et al, 1991) have reported skin effects associated with occupational exposures to TDI. While it is often unclear if the skin effects are attributable to primary irritation or sensitization, there is a suggestion that irritant dermatitis is more common than allergic contact dermatitis (Daftarian et al, 2002).…”

“…While it is often unclear if the skin effects are attributable to primary irritation or sensitization, there is a suggestion that irritant dermatitis is more common than allergic contact dermatitis (Daftarian et al, 2002). In subjects with occupational skin disease, approximately 2% of the 360 patients investigated showed evidence of skin irritation when 15 mg of a 1.5% or 2% TDI solution was applied to the skin for two days (Kanerva et al, 1999).…”

“…In a flexible foam plant, 26 TDI exposed workers reporting skin symptoms underwent patch testing with a 2% TDI solution, none developed a reaction to the TDI antigen (Daftarian et al, 2002). In addition, only 1% of dermatology patients with a suspected sensitivity to diisocyanates demonstrated an allergic skin reaction to TDI (Liippo and Lammintausta, 2008).…”