Isocyanates are skin sensitizing chemicals and workers handling them need affordable but adequate skin protection to minimize the risk of developing allergic contact dermatitis. Current standardized permeation and penetration test methods are mainly designed for liquid chemicals of low to medium toxicity. The breakthrough time in the EN 374-3:2003 and FprEN 16523-1 standards does not represent safe limits for sensitizing chemicals. Clothing materials cannot usually be tested with this standard procedure. Hence, two sensitive test methods, one permeation and one penetration, were developed and validated at the FIOH by using the commonly used isocyanate MDI as an example. MDI-polyol formulations undergoing hardening into polyurethane were also successfully used in the penetration test.
Dose per unit area is considered the most important factor in skin sensitization.
Therefore the test results are reported as cumulative permeation and penetration (µg/cm2) for a certain time period. With this approach different test results can also be compared to each other and to the proposed safe limit, 1 µg/cm2. Affordable glove and clothing material that can provide adequate protection during short contact with MDI were found. These new test procedures should be standardized or included into the present EN ISO standards.
The studies were funded by the Finnish Work Environment Fund and the International Isocyanate Institute.
Permeation Tests of Glove and Clothing Materials Against Sensitizing Chemicals Using Diphenylmethane Diisocyanate as an Example, Ann Occup Hyg (2014) 58 (7): 921-930 first published online June 16, 2014 doi:10.1093/annhyg/meu040: http://annhyg.oxfordjournals.org/content/58/7/921.abstract
A New Penetration Test Method: Protection Efficiency of Glove and Clothing Materials Against Diphenylmethane Diisocyanate (MDI), Ann Occup Hyg first published online October 16, 2014 doi:10.1093/annhyg/meu078