Workers in the electrical apparatus industry probably needn't be too concerned about it, but we can't be certain. Nationwide publicity during this past year has highlighted possible risks in exposure to a chemical that's an important epoxy resin ingredient: Bisphenol-A, or BPA. Whatever the danger, how does exposure occur? Besides epoxy resins used in VPI processing of electrical apparatus, BPA is a common ingredient in hard plastic polycarbonate containers -- notably baby bottles -- and as a liner in food cans. Tests show that over time the chemical leaches out into the contents of such containers. Meanwhile, manufacturers are looking at ways to eliminate BPA from their products. Minimizing contact with BPA-based resins would seem to be prudent behavior.