Exhibit 21

Subsidiaries of Esmark Incorporated



|                                             |  |                                   
|-------------------------------------------- |  | ----------------------------------
|Name of Subsidiary                           |  | State/Jurisdiction of Organization
|                                             | 
|Wheeling-Pittsburgh Corporation              |  | Delaware                          
|                                             | 
|WP Steel Venture Corporation                 |  | Delaware                          
|                                             | 
|Consumers Mining Company                     |  | Pennsylvania                      
|                                             | 
|Monessen Southwestern Railway Company        |  | Pennsylvania                      
|                                             | 
|Wheeling-Pittsburgh Steel Corporation        |  | Delaware                          
|                                             | 
|Metal Centers LLC                            |  | Delaware                          
|                                             | 
|Esmark Steel Service Group, Inc.             |  | Delaware                          
|                                             | 
|Century Steel Company LLC                    |  | Illinois                          
|                                             | 
|North American Steel LLC                     |  | Illinois                          
|                                             | 
|Electric Coating Technologies LLC            |  | Delaware                          
|                                             | 
|Electric Coating Technologies Bridgeview LLC |  | Illinois                          
|                                             | 
|Great Western Steel Company LLC              |  | Illinois                          
|                                             | 
|Great Western Realty LLC                     |  | Illinois                          
|                                             | 
|Independent Steel Company LLC                |  | Illinois                          
|                                             | 
|Miami Valley Steel Service, Inc.             |  | Ohio                              
|                                             | 
|Premier Resource Group LLC                   |  | Illinois                          
|                                             | 
|Sun Steel Company LLC                        |  | Illinois                          
|                                             | 
|U.S. Metals & Supply LLC                     |  | Illinois                          
|                                             | 
|Esmark Realty LLC                            |  | Illinois                          
|                                             | 
|Century Steel Realty LLC                     |  | Illinois                          
|                                             | 
|ISCO Realty LLC                              |  | Illinois                          
|                                             | 
|Miami Valley Realty LLC                      |  | Illinois                          
|                                             | 
|Sun Steel Realty LLC                         |  | Illinois                          
|                                             | 
|U.S. Metals Realty LLC                       |  | Illinois                          
|                                             | 
|E2Acquisition Corporation                    |  | Delaware                          
|                                             | 
|BIP Acquisition Sub, Inc.                    |  | Delaware