I work with someone who usually  wears polo shirts that he receives from a trade show with another company's name on it.  We were wondering if we could force him to actually dress more appropriately for the office.  I believe so after checking out the New York Department of Labor website. In their Frequently Asked Questions they had the following question

Q. Can employers require their employees to wear uniforms?

A: Yes, however, the cost of purchasing and/or maintaining a uniform must not bring the employee below the minimum wage. If workers at the minimum wage rate must wear a uniform, their employers must clean and maintain them or pay the employees to do so. Ordinary clothing (such as black trousers and white shirts) are generally not considered "uniforms."

I assume that their are other rules relating to appropriate attire and such (so it is not an absolute right).

So not only can we require him to wear dress shirts, we can dictate the color.  So the question will be, what color should we make Chris wear?