Employees who express concerns of unethical or illegal behavior within their companies to outside authorities, after attempting to go through normal channels at work, are known as

They are known as whistleblower.
Whistleblower is anyone that disclose secret information from any establishment that are pretty much illecal/unethical in nature.
In united states, the OSHA ensure that the right and safety of the whistleblowers will always be assured assuming the information is accurate