Any state health agency would fall under the executive branch of government. The power of creating laws is under the legislative branch (like the Senate). Executive agencies have the authority to enforce laws and under Chevron Deference the authority to interpret laws where vague, but not form new laws.
For example, if a bill was passed saying cars can’t be louder than 110 dBs an executive agency could decide the proper way of measuring volume, if not prescribed by law.