| Business | Phone |
| Zambrana Engineering Inc 225 W Main St, Collinsville 62234 | (618) 344-3300 |
| Volkert & Assoc Inc 2 Eastport Plaza Dr, Collinsville 62234 | (618) 345-8918 |
| Geotechnology Inc 850 Vandalia St 230, Collinsville 62234 | (618) 345-4811 |
| Oates Associates Inc 100 Lanter Ct, Collinsville 62234 | (618) 345-2200 |