| Business | Phone |
| Affiliated Engineers Inc 671 S Bryan St, Elmhurst 60126 | (630) 993-1004 |
| American Engineering Conslnts 188 W Industrial Dr 203, Elmhurst 60126 | (630) 941-7750 |
| Armstrong Aerospace 111 N Addison Ave, Elmhurst 60126 | (630) 782-6400 |
| Blm Engineers Inc 410 E Schiller St, Elmhurst 60126 | (630) 766-9200 |
| Edgecon Environmental Inc 475 W Wrightwood Ave, Elmhurst 60126 | (630) 832-5904 |
| Claude H Hurley Co 175 W 1st St, Elmhurst 60126 | (630) 279-7762 |
| Delta Control Design 384 Schiller St, Elmhurst 60126 | (630) 941-1232 |
| Gouwens Engineering Consultant 520 S York St, Elmhurst 60126 | (630) 834-0330 |