A questionnaire survey was carried out among electron microscopy (EM) laboratory technicians in Finland. The questionnaire was returned by 18 out of the total of 45 to 50 EM workers, covering 13 laboratories. Epoxy resins, especially glycidyl ethers of glycerol, anhydride hardeners, amine accelerators, and propylene oxide, where used for embedding. On average, the technicians had been exposed to unpolymerized epoxy resins for 3 h a week over a 10-year period. Ten workers reported skin symptoms. Seventeen used protective gloves when working with unpolymerized resins.
In gas chromatography, the epoxy resins were found to contain many skin sensitizing compounds, that is, diglycidyl ether of bisphenol A (molecular weight 340) and epoxy reactive diluents. This potential allergenic capacity of the epoxy resins emphasizes the importance of preventing skin contact.
Selection of glove material for the handling of tissue specimens in electron microscopy laboratories was based on the results of permeation tests with propylene oxide, because the chemical construction of propylene oxide is similar to that of sensitizing epoxy compounds. Because it is a low viscosity compound, however, propylene oxide penetrates glove material more rapidly than the resin compounds.
Thin polyethylene gloves provide better protection against propylene oxide, and thus also against embedding resins, than disposable polyvinyl chloride (PVC) or natural rubber gloves.