Exhibit 21 - Subsidiaries of the Registrant Advance Petroleum, Inc., a Florida corporation (1) Advance Aviation Services, Inc., a Florida corporation (10) AirData Limited, a United Kingdom corporation (2) Air Terminaling, Inc., a Florida corporation (10) Baseops Europe Ltd., a United Kingdom corporation (3) Baseops International, Inc., a Texas corporation Casa Petro S.A., a Costa Rica corporation Cherokee Group, Inc., a Florida corporation International Environmental Services, Inc., a Florida corporation International Petroleum Corporation, a Florida corporation (4) International Petroleum Corporation of LA, a Louisiana corporation (4) International Petroleum Corporation of Lafayette, a Louisiana corporation International Petroleum Corporation of Maryland, a Maryland corporation (4) International Petroleum Corp. of Delaware, a Delaware corporation (4) International Petroleum Corp. of Georgia, a Georgia corporation (10) International Petroleum Corp. of Pennsylvania, a Pennsylvania corporation (10) Pacific Horizon Petroleum Corporation, a Delaware corporation PetroServicios de Costa Rica S.A., a Costa Rica corporation (5) PetroServicios de Mexico S.A. de C.V., a Mexico corporation (6) PetroServicios WFS del Peru, S.A., a Peru corporation (9)(10) Resource Recovery Atlantic, Inc., a Delaware corporation (7)(10) Resource Recovery Mid South, Inc., a Virginia corporation (7)(10) Resource Recovery of America, Inc., a Florida corporation (10) Servicios Auxiliares de Mexico S.A. de C.V., a Mexico corporation (6) Trans-Tec Argentina S.A., an Argentina corporation (10) Trans-Tec International S.A., a Costa Rica corporation Trans-Tec Services, Inc., a Delaware corporation Trans-Tec Services (UK) Ltd., a United Kingdom corporation Trans-Tec Services (Singapore) PTE. Ltd., a Singapore corporation (8) World Fuel International S.A., a Costa Rica corporation World Fuel Miami, Inc., a Florida corporation (10) World Fuel Services, Inc., a Texas corporation World Fuel Services, Ltd., a United Kingdom corporation World Fuel Services (Singapore) PTE. Ltd., a Singapore corporation World Fuel Services of Chile S.A., a Chile corporation (6)(10) World Fuel Services del Peru, S.A., a Peru corporation (9)(10) (1) Advance Petroleum, Inc., operates under the name "World Fuel Services of FL. (2) This corporation is a wholly-owned subsidiary of Baseops Europe Ltd. (3) This corporation is a wholly-owned subsidiary of Baseops International, Inc. (4) These corporations collect and purchase used oil under the name "International Oil Service." (5) This corporation is owned 55% by Casa Petro S.A. and 45% by World Fuel Services Corporation. (6) This corporation is owned 50% by Advance Aviation Services, Inc. and 50% by Air Terminaling, Inc. (7) These corporations are wholly-owned subsidiaries of Resource Recovery of America, Inc. (8) This corporation is a wholly-owned subsidiary of Trans-Tec Services (UK) Ltd. (9) These corporations are owned 99% by World Fuel Services Corporation and 1% by Advance Aviation Services, Inc. 10) Inactive.