EXHIBIT 21 SPARTECH CORPORATION SUBSIDIARIES OF REGISTRANT Legal Entity DBA Incorporation Atlas Alchem Plastics, Inc. Spartech Plastics DE Spartech Compounding The Resin Exchange, Inc. Spartech Compounding MO Resin Exchange Franklin-Burlington Plastics, Inc. Spartech Compounding DE Spartech Vy-Cal Plastics Alchem Plastics, Inc. Spartech Plastics DE Alchem Plastics Corporation Spartech Plastics GA Spartech Plastics, Inc. Spartech Plastics DE Portage Industries Preferred Plastics Spartech Industries, Inc. Hamelin Industries DE Spartech Canada, Inc. GM Plastics New Brunswick, Genpak Canada Spartech Enterprises Korlin