| Business | Phone |
| Baltimore Local 19 Merriweather Post Pavilion, Columbia 21044 | (410) 730-2848 |
| Local 669 Jatc Cmplnce 7050 Oakland Mills Rd, Columbia 21046 | (410) 309-6580 |
| Local Union 669 Sprinkler 7050 Oakland Mills Rd, Columbia 21046 | (410) 381-4301 |
| Professional Staff Nurses Assn 10630 Little Patuxent Pkwy, Columbia 21044 | (301) 596-1142 |
| Sprinkler Fitters Joint 7050 Oakland Mills Rd, Columbia 21046 | (410) 312-5202 |