| Business | Phone |
| Conti Environmental Inc 5210 Chairmans Ct, Frederick 21703 | (301) 624-0034 |
| Heinemann's Environmental 1569 Saint Lawrence Ct, Frederick 21701 | (301) 668-2614 |
| Lagus Applied Technology 201 Broadway St # A, Frederick 21701 | (301) 774-4012 |
| Rad Electric Inc 5714 Industry Ln # C, Frederick 21704 | (301) 694-0011 |