CEO's should do a variety of things to stop sexual harassment in the work place. The most important thing is senior management makes it clear to workers that harassment in any form won't be tolerated. If top managers don' take the issues seriously, employees won't either. Managers must also understand they are responsible for their employees. Companies need an explicit written policy on sexual harassment that is widely available in the workplace.
Most consultants advise companies to do more than just post the policy on bulletin boards.
They should distribute it company wide, repeatedly. Copies should be included in new employee orientation packets. Employees should have clear definitions of what sexual harassment is and isn't. Many companies are now offering employee training sessions on sexual harassment, and many say that follow up training is a good idea. Training programs should include all employees, rather than just managers.