Hair restraints must be worn. The ultimate power is always up to the local board of health. You really dont have the power to make them cut it but you absolutely have the power to require a hair restraint. The local in my area allows hats but for anyone with more hair or longer hair he requires a hair net in addition to the hat. If you are a cook you should absolutely know this and expect it. Some of the cooking shows that feature profesiionals make some of these young bucks think they are superstars and dont need hair restraints. It is crazy. If they dont like it then they can walk away. I have a beard. Not super long and kept clean. I worked in one district that made me wear a bra over it (beard restraint) and turned down a job because the local agent did not allow facial hair at all. My current one allows it as long as it is trimmed and clean. Being in the industry it is part of the proper food safety protocol. It is the same reason in this industry we have to enforce and address cleanliness. You must shower and be clean and wear a proper hair restraint. You absolutely can tsell someone this is a condition of employment.