| Business | Phone |
| Taj Engineering 1 Olde North Rd # 201, Chelmsford 1824 | (978) 250-8173 |
| Flaherty Associates Inc 4 Courthouse Ln # 14, Chelmsford 1824 | (978) 250-1400 |
| Phelan Engineering 12 Sleigh Rd, Chelmsford 1824 | (978) 256-4014 |
| H-Star Engineering Inc 9 Acton Rd # 17, Chelmsford 1824 | (978) 256-9216 |