| Business | Phone |
| Bae Systems 879 Autumn Grove Dr, O Fallon 63366 | (636) 978-1355 |
| Herman Engineering Svc 166 Royallprairie Ln, O Fallon 63368 | (636) 281-3666 |
| Gettemeyer Engineering 2588 Highway K, O Fallon 63368 | (636) 978-1954 |
| Entec Consulting 2481 Trudy Rose Cir, O Fallon 63366 | (636) 272-2284 |