| Business | Phone |
| Kudrna & Assoc 203 N Cass Ave, Westmont 60559 | (630) 969-3060 |
| Middough Associates Inc 999 Oakmont Plaza Dr 400, Westmont 60559 | (630) 734-7000 |
| Parsons Engineering Science 999 Oakmont Plaza Dr 420, Westmont 60559 | (630) 371-1800 |
| Rimkus Consulting Group Inc 999 Oakmont Plaza Dr, Westmont 60559 | (630) 321-1846 |
| Siemens Westinghouse 601 Oakmont Ln 180, Westmont 60559 | (630) 850-4800 |