In addition to quitting Iwould write a letter (kind of an exit interview) explaining your reason for lieving and then mail it to the company to the insurance company that provides the liability and workers compensation and also to the authority having jurisdiction, (city, county or other appropriate governing body that has an agency that inforces safe work regulations).
By doing that you would be taking the next step (doing all you could) to protect the new employee from the hazards that he can't possibly be aware of which is mostly a stupid boss.
