SUBSIDIARIES OF MDU RESOURCES GROUP, INC. December 31, 1996 State or Other Jurisdiction in Which Incorporated Alaska Basic Industries, Inc. Alaska Anchorage Sand and Gravel Company, Inc. Alaska Baldwin Contracting Company, Inc. California Centennial Energy Holdings, Inc. Delaware Concrete, Inc. California Customer One, Inc. Delaware Fidelity Oil Co. Delaware Fidelity Oil Holdings, Inc. Delaware KRC Aggregate, Inc. Delaware KRC Holdings, Inc. Delaware Knife River Corporation Minnesota Knife River Hawaii, Inc. Delaware Knife River Marine, Inc. Delaware LTM, Incorporated Oregon Medford Ready Mix, Inc. Delaware Prairie Propane, Inc. Delaware Prairielands Energy Marketing, Inc. Delaware Rogue Aggregates, Inc. Oregon WBI Canadian Pipeline, Ltd. Canada Williston Basin Interstate Pipeline Company Delaware