Abstract: Apparatus and methods of abating the objectionable emissions of volatile hydrocarbons generated during the preheating cycle of a twin vessel electric arc furnace steelmaking operation wherein the vessels cycle between a powered or melting state and an unpowered state. During the unpowered state, scrap charged to the non-powered vessel is preheated. The spent off-gases from the non-powered vessel may contain toxic and/or noxious hydrocarbons therein by virtue of certain plastics and/or grease/oils mixed with the scrap being preheated. The spent off-gas from the preheat vessel is delivered to a combustion chamber to be mixed with a hot off-gas diverted from the powered vessel. The temperature of the mixed off-gases in the combustion chamber is raised to a critical temperature to burn/crack the objectionable hydrocarbons, which may include dioxins and furans.