Attacked by another employee but the board will not take action

[ke5noi]

I was recently attacked by another employee for asking that the tv be muted while i was giving an ambulance crew response times for their report. The attack was verbal but it included many insulting and vulgar remarks including sexual insults and insults about disibilities i have worked hard to live with and overcome. At the first meeting 2 other employees came forth with written letters stating that the employee that attacked me had been planning for weeks to pick a fight with me and then drive the streets looking for me and physically attack me if she got fired for it. at a second meeting the board took no action other than to warn her to behave and that was their final decision. her plan to pick a fight was to play BET (black entertainment television) and rap music untill i couldent stand it any more and then teach me a lesson if i said anything about it. This was a preplanned attack on me by another employee and the board chooses not to take any action. What should i do. There is a history of these incidents with her and other employees. Would i have grounds to sue the board for not providing a safe work enviroment. The sad part this is taking place in a E911 center where things like this could have adverse effects on the quality of service provided to the residents we serve and also the fire police and ems units that depend on us.