| SMW Local 17 JATC | Related tax-exempt org | Training fund | MA | 222562168 |
| SMW Local 17 Union | Related tax-exempt org | Union | MA | 046133804 |
| SMW Local 17 Annuity Fund | Related tax-exempt org | Employee benefit fund | MA | 046394579 |
| SMW Local 17 Equality | Related tax-exempt org | Employee benefit fund | MA | 042740831 |
| SMW Local 17 Supplemental Pension Fund | Related tax-exempt org | Employee benefit fund | MA | 200845880 |
| Advance AIR & HEAT | Related taxable corporation/trust | — | MA | — |
| AERO Mechanical INC | Related taxable corporation/trust | — | RI | — |
| Aerodyne Mechanical Contractor | Related taxable corporation/trust | — | MA | — |
| AIR Distribution Corp | Related taxable corporation/trust | — | MA | — |
| Alliance Sheet Metal (boston) | Related taxable corporation/trust | — | MA | — |
| APEX Corporation | Related taxable corporation/trust | — | MA | — |
| Atlantic Contracting & Special | Related taxable corporation/trust | — | NH | — |
| Bennett CAD Systems INC | Related taxable corporation/trust | — | MA | — |
| Blouin Service LLC | Related taxable corporation/trust | — | NH | — |
| CCB INC | Related taxable corporation/trust | — | ME | — |
| Boston AIR Systems | Related taxable corporation/trust | — | MA | — |
| Architectural Sheet Metal | Related taxable corporation/trust | — | MA | — |
| Kleeberg Sheet Metal INC | Related taxable corporation/trust | — | MA | — |
| Bryant Sheet Metal | Related taxable corporation/trust | — | MA | — |
| BTEA | Related taxable corporation/trust | — | MA | — |
| Buckley Associates | Related taxable corporation/trust | — | MA | — |
| Charles P Blouin INC | Related taxable corporation/trust | — | MA | — |
| Commonwealth BLDG Systems | Related taxable corporation/trust | — | MA | — |
| Commonwealth Ventilation | Related taxable corporation/trust | — | MA | — |
| COX Engineering Company | Related taxable corporation/trust | — | MA | — |