| Business | Phone |
| Crawford Engineering Assoc 3120 Ne Us Grant Pl, Portland 97212 | (503) 282-6831 |
| Darden Engineering Inc 5319 Sw Westgate Dr # 32, Portland 97221 | (503) 297-8400 |
| Du Pont Engineering Corp 621 Sw Morrison St # 1125, Portland 97205 | (503) 274-0908 |
| Perteet Engineering 121 Sw Salmon St # 950, Portland 97204 | (503) 225-1500 |