**Exhibit 21.1**

**Subsidiaries(1)**
| **Subsidiaries of Lone Star Technologies. Inc.**  | ** ** | **Jurisdiction of Incorporation/Organization** |
|---------------------------------------------------|------------|------------------------------------------------|
|                                              |       |                                           |
| Environmental Holdings, Inc.                      |       | Delaware                                       |
| Zinklahoma, Inc.                                  |       | Delaware                                       |
| Zinkanada, Inc.                                   |       | Canada                                         |
| Fintube Technologies, Inc.                        |       | Oklahoma                                       |
| Lone Star Steel Company, L.P.                     |       | Delaware                                       |
| Star Capital Funding, Inc.                        |       | Delaware                                       |
| Star Energy Group, LLC                            |       | Delaware                                       |
| Star TC Holdings, LLC                             |       | Texas                                          |
| Apolo Tubulars S.A. (50%)                         |       | Brazil                                         |
|                                              | ** ** | ** **                                     |
| **Subsidiaries of Lone Star Steel Company, L.P.** | ** ** | ** **                                     |
|                                              |       |                                           |
| Lone Star Logistics, Inc.                         |       | Texas                                          |
| Lone Star Steel International, L.P.               |       | Delaware                                       |
| Lone Star Steel Mexico, LLC                       |       | Texas                                          |
| Lone Star Steel International de Mexico,          |       | Mexico                                         |
| S. de R.L. de  C.V. (65%)                         |       |                                           |
| Lone Star Steel Sales Company                     |       | Delaware                                       |
| Rotac, Inc.                                       |       | Texas                                          |
| Star Tubular Services, Inc.                       |       | Texas                                          |
| Texas & Northern Railway Company              |       | Texas                                          |
| ** **                                        |       |                                           |
| **Subsidiaries of Fintube Technologies, Inc.**    |       |                                           |
|                                              |       |                                           |
| Fintube Canada, Inc.                              |       | Delaware                                       |
| Fintube (Thailand) Limited                        |       | Thailand                                       |
| Aletas y Birlos Mexicana, S.A. de C.V.            |       | Mexico                                         |
| Aletas y Birlos, S.A. de C.V.                     |       | Mexico                                         |
| ** **                                        | ** ** | ** **                                     |
| **Subsidiaries of Star Energy Group, LLC**        | ** ** | ** **                                     |
|                                              |       |                                           |
| Bellville Tube Company, L.P.                      |       | Texas                                          |
| Delta Tubular International, L.P.                 |       | Texas                                          |
| Delta Tubular Processing, L.P.                    |       | Texas                                          |
| Wheeling Machine Products, L.P.                   |       | Texas                                          |

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(1)             Includesboth direct and in direct subsidiaries.

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