| Business | Phone |
| Ardmore Associates 33 N Dearborn St # 2323, Chicago 60602 | (312) 795-1400 |
| Black & Veatch 101 N Wacker Dr 1100, Chicago 60606 | (312) 346-3775 |
| Bowman Barrett O'Hare 5600 N Mannheim Rd, Chicago 60666 | (773) 686-1070 |
| Camp Dresser & Mc Kee Inc 125 S Wacker Dr 600, Chicago 60606 | (312) 346-5000 |
| Feinstein Glaser Olney & Co 555 W Jackson Blvd 301, Chicago 60661 | (312) 629-8401 |
| Eyring & Assoc 1149 W Farwell Ave, Chicago 60626 | (773) 743-1635 |
| Carter & Burgess Inc 30 S Wacker Dr 2200, Chicago 60606 | (312) 466-5723 |
| Eventive Llc 203 N La Salle St 2100, Chicago 60601 | (312) 558-1390 |
| Eln Inc 36 S Wabash Ave, Chicago 60603 | (312) 236-7909 |
| Drs Technologies Inc 410 S Michigan Ave, Chicago 60605 | (312) 957-1529 |
| Earth Tech Inc 111 N Canal St # 305, Chicago 60606 | (312) 902-6903 |
| Commonsense Consulting 6351 W Montrose Ave, Chicago 60634 | (773) 736-3660 |
| Cosentini Associates 1 E Wacker Dr, Chicago 60601 | (312) 670-1800 |