Exhibit 21 EQUITABLE RESOURCES, INC. SUBSIDIARY COMPANIES Andex Energy, Inc. EQT Capital Corporation Equitable Pipeline Company Equitable Power Services Company Equitable Resources (Argentina) Company Equitable Resources Energy Company Equitable Storage Company, L.L.C. Equitrans, L.P. EREC Canada Ltd. EREC Nevada, Inc. ERI Enterprises, L.L.C. ERI Global Partners, Inc. ERI Holdings ERI Holdings II ERI Investments, Inc. ERI JAM, LLC ERI Power Services Canada Ltd. ERI Services Canada Ltd. ERI Services, Inc. ERI Services (St. Lucia) Limited ERI Trading Company ET Avoca Company ET Blue Grass Company ET Development Company, L.L.C. 420 Energy Investments, Inc. IEC Hunterdon, Inc. IEC Management Services, Inc. IEC Montclair, Inc. IEC Plymouth, Inc. Independent Energy Corporation Independent Energy Finance Corporation Independent Energy Operations, Inc. Kentucky West Virginia Gas Company, L.L.C. LIG Chemical Company LIG, Inc. LIG Liquids Company L.L.C. Louisiana Intrastate Gas Company L.L.C. Nora Transmission Company Northeast Energy Services, Inc. Three Rivers Pipeline Corporation Three Rivers UtiliCom, Inc. Tuscaloosa Pipeline Company