Exhibit 21. Subsidiaries of the Registrant Percentage State or country of voting in which securities incorporated owned Registrant: Dravo Corporation Pennsylvania -- Subsidiaries of Dravo Corporation: Dravo Basic Materials Company, Inc. Alabama 100% Dravo Equipment Delaware 100 Dravo Lime Company Delaware 100 Princeton Ridge, Inc. New Jersey 100 Subsidiary of Dravo Basic Materials Company, Inc.: Dravo Natural Resources Company Delaware 50 Subsidiary of Dravo Lime Company: Dravo Natural Resources Company Delaware 50 21-1