A one-part epoxy structural adhesive comprising an epoxy resin, a toughening agent, a reactive liquid modifier present in an amount ranging from about 5% to about 15% by weight structural adhesive, and a latent amine curing agent. The structural adhesive may optionally include reactive diluents, synthetic mineral fibers, fillers, pigments and combinations th The structural adhesive may be used to form bonded joints between metal parts having clean surfaces, as well as those having surfaces contaminated with hydrocarbon-containing materials, such as oils, processing aids and lubricating agents.