| Business | Phone |
| Apwu Columbia Area Local 2001 Dixiana Rd, West Columbia 29172 | (803) 791-7402 |
| Communications Workers-America 566 Chris Dr, West Columbia 29169 | (803) 791-3706 |
| Mail Handlers Local 334 1625 Charleston Hwy, West Columbia 29169 | (803) 791-7219 |
| Unite 1625 Charleston Hwy # E, West Columbia 29169 | (803) 926-8686 |