| SMW Local Union 218 | Related tax-exempt org | To organize workers for their economic, moral and social advancement | IL | 371220876 |
| EL Pruitt | Related taxable corporation/trust | — | IL | — |
| Designed ROOF | Related taxable corporation/trust | — | IL | — |
| Prairie State PLBG & HTG | Related taxable corporation/trust | — | IL | — |
| MIKE Williams INC | Related taxable corporation/trust | — | IL | — |
| Dixon's Heating AC | Related taxable corporation/trust | — | IL | — |
| Leach Remmers INC | Related taxable corporation/trust | — | IL | — |
| Henson Robinson CO | Related taxable corporation/trust | — | IL | — |
| HRI Jacksonville | Related taxable corporation/trust | — | IL | — |
| Lincoln HTG & Cooling INC | Related taxable corporation/trust | — | IL | — |
| Airmaster HTG & Cooling | Related taxable corporation/trust | — | IL | — |
| Brennan Htg & AC | Related taxable corporation/trust | — | IL | — |
| Crown Corr Inc | Related taxable corporation/trust | — | IL | — |
| King LAR | Related taxable corporation/trust | — | IL | — |
| Roofing Associates LLC | Related taxable corporation/trust | — | IL | — |
| A&R Mechanical | Related taxable corporation/trust | — | IL | — |
| Advanced Commerical | Related taxable corporation/trust | — | IL | — |
| Airtech Test & Balance | Related taxable corporation/trust | — | IL | — |
| BEC Mechanical | Related taxable corporation/trust | — | IL | — |
| Bennett & Brosseau | Related taxable corporation/trust | — | IL | — |
| Certified Testing | Related taxable corporation/trust | — | IL | — |
| Davis HOUK Mechancial | Related taxable corporation/trust | — | IL | — |
| EAST Coast Metal Systems | Related taxable corporation/trust | — | IL | — |
| EAST Moiline Sheet Metal | Related taxable corporation/trust | — | IL | — |
| Industrial Services of Illinois | Related taxable corporation/trust | — | IL | — |