Provided is a continuous process for converting waste plastic into recycle for polyethylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene and preparing a stable blend of petroleum and the selected plastic. The amount of plastic in the blend comprises no more than 20 wt. % of the blend. The blend is passed to a refinery FCC unit. A liquid petroleum gas LPG olefin/paraffin mixture and naphtha are recovered from the FCC unit and passed to a steam cracker to make ethylene.