A new employee's first exposure to a real hazard usually happens before their direct deposit form gets filed. They signed the handbook at 8:00, watched a video at 8:45, and by 9:30, they're on the floor, shadowing someone who's worked there for 11 years and has stopped noticing what's dangerous about the job.
That gap is what new hire safety training exists to close. And it's why a signature on an orientation packet isn't the same thing as a trained employee.