Your problem is two-fold here. One problem is as you know the carry concealed laws are very very restrictive in DC so firearms are likely not going to be an option for you unless laws change significantly in favor of gun owners. You may know that the Supreme Court just this year ruled that DC residents could have guns in their homes. With regard to other non-lethal means of protecting yourself, ask your local police jurisdiction specifically what itmes can and cannot be concealed, and then ask a loca criminal defense attorney to confirm what the police tell you. Your second issue is that even if your method of self defense is legal in the District and surrounding VA or MD you still may be in violation of company policy by carrying into your workplace. Check your employee manual. I would not recommend that you ask HR as they may interpret your desire for self defense as a threat to create an unsafe work environment. You should research what non-concealed weapons you can carry in the district. A weapon that can be seen is a greater deterent to a criminal than a weapon that is hidden away. On a more practical note, a self defense class or several may serve you better. Most persons who are attacked are attacked by surprise and have no opportunity to get their hands on concealed weapons to avoid attack. Additionally, if your attacker discovers that you have a weapon his violence against you may escalate and the very weapon that you intended to use against him may be used against you.