Abstract: Complexly-shaped articles of EPDM material are treated with benzophenone by cleaning the article, coating it with benzophenone and irradiating the benzophenone-coated article with ultraviolet light. The complexly-shaped articles are uniformly treated by exposure within a reflective enclosure that bathes the article in light by transporting it while rotating around an ultraviolet source and between the source and the reflective enclosure.